Latest Publications

@article{simkova_dual_2016,

title = {The dual role of asporin in breast cancer progression.},

author = {Dana Simkova and Gvantsa Kharaishvili and Gabriela Korinkova and Tomas Ozdian and Tereza Suchánková-Kleplová and Tomas Soukup and Michal Krupka and Adela Galandakova and Petr Dzubak and Maria Janikova and Jiri Navratil and Zuzana Kahounova and Karel Soucek and Jan Bouchal},

doi = {10.18632/oncotarget.10471},

issn = {1949-2553},

year  = {2016},

date = {2016-08-01},

journal = {Oncotarget},

volume = {7},

number = {32},

pages = {52045–52060},

abstract = {Asporin has been reported as a tumor suppressor in breast cancer, while asporin-activated invasion has been described in gastric cancer. According to our in silico search, high asporin expresion associates with significantly better relapse free survival (RFS) in patients with low-grade tumors but RFS is significantly worse in patients with grade 3 tumors. In line with other studies, we have confirmed asporin expression by RNA scope in situ hybridization in cancer associated fibroblasts. We have also found asporin expression in the Hs578T breast cancer cell line which we confirmed by quantitative RT-PCR and western blotting. From multiple testing, we found that asporin can be downregulated by bone morphogenetic protein 4 while upregulation may be facilited by serum-free cultivation or by three dimensional growth in stiff Alvetex scaffold. Downregulation by shRNA inhibited invasion of Hs578T as well as of CAFs and T47D cells. Invasion of asporin-negative MDA-MB-231 and BT549 breast cancer cells through collagen type I was enhanced by recombinant asporin. Besides other investigations, large scale analysis of aspartic acid repeat polymorphism will be needed for clarification of the asporin dual role in progression of breast cancer.},

note = {Place: United States},

keywords = {3D cultivation, asporin, Breast cancer, Breast Neoplasms/metabolism/mortality/*pathology, Disease-Free Survival, Extracellular Matrix Proteins/*metabolism, Female, Fibroblasts/metabolism/pathology, grade, Humans, Kaplan-Meier Estimate, Prognosis, stiffness, Tumor Microenvironment/physiology},

pubstate = {published},

tppubtype = {article}

}

@article{brenerova_pure_2016,

title = {Pure non-dioxin-like PCB congeners suppress induction of AhR-dependent endpoints in rat liver cells.},

author = {Petra Brenerová and Timo Hamers and Jorke H. Kamstra and Jan Vondráček and Simona Strapáčová and Patrik L. Andersson and Miroslav Machala},

doi = {10.1007/s11356-015-4819-6},

issn = {1614-7499 0944-1344},

year  = {2016},

date = {2016-02-01},

journal = {Environmental science and pollution research international},

volume = {23},

number = {3},

pages = {2099–2107},

abstract = {The relative potencies of non-ortho-substituted coplanar polychlorinated biphenyl (PCB) congeners to activate the aryl hydrocarbon receptor (AhR) and to cause the AhR-dependent toxic events are essential for their risk assessment. Since some studies suggested that abundant non-dioxin-like PCB congeners (NDL-PCBs) may alter the AhR activation by PCB mixtures and possibly cause non-additive effects, we evaluated potential suppressive effects of NDL-PCBs on AhR activation, using a series of 24 highly purified NDL-PCBs. We investigated their impact on the model AhR agonist-induced luciferase reporter gene expression in rat hepatoma cells and on induction of CYP1A1/1B1 mRNAs and deregulation of AhR-dependent cell proliferation in rat liver epithelial cells. PCBs 128, 138, and 170 significantly suppressed AhR activation (with IC50 values from 1.4 to 5.6 μM), followed by PCBs 28, 47, 52, and 180; additionally, PCBs 122, 153, and 168 showed low but still significant potency to reduce luciferase activity. Detection of CYP1A1 mRNA levels in liver epithelial cells largely confirmed these results for the most abundant NDL-PCBs, whereas the other AhR-dependent events (CYP1B1 mRNA expression, induction of cell proliferation in confluent cells) were less sensitive to NDL-PCBs, thus indicating a more complex regulation of these endpoints. The present data suggest that some NDL-PCBs could modulate overall dioxin-like effects in complex mixtures.},

note = {Place: Germany},

keywords = {Animals, Aryl hydrocarbon receptor, Aryl Hydrocarbon/genetics/*metabolism, Cell Line, Cell Proliferation/drug effects, Cytochrome P-450 CYP1A1/genetics/metabolism, Cytochrome P450, Disruption of contact inhibition, DR-CALUX® assay, Epithelial Cells/cytology/drug effects/metabolism, Gene Expression/drug effects, Hepatocytes/cytology/drug effects/metabolism, Liver/*drug effects/metabolism, NDL-PCBs, Polychlorinated Biphenyls/*chemistry/*toxicity, Rats, Receptors, Relative effect potency, Signal Transduction/drug effects},

pubstate = {published},

tppubtype = {article}

}

@article{vondracek_environmental_2016,

title = {Environmental Ligands of the Aryl Hydrocarbon Receptor and Their Effects in Models of Adult Liver Progenitor Cells.},

author = {Jan Vondráček and Miroslav Machala},

doi = {10.1155/2016/4326194},

issn = {1687-966X 1687-9678},

year  = {2016},

date = {2016-01-01},

journal = {Stem cells international},

volume = {2016},

pages = {4326194},

abstract = {The toxicity of environmental and dietary ligands of the aryl hydrocarbon receptor (AhR) in mature liver parenchymal cells is well appreciated, while considerably less attention has been paid to their impact on cell populations exhibiting phenotypic features of liver progenitor cells. Here, we discuss the results suggesting that the consequences of the AhR activation in the cellular models derived from bipotent liver progenitors could markedly differ from those in hepatocytes. In contact-inhibited liver progenitor cells, the AhR agonists induce a range of effects potentially linked with tumor promotion. They can stimulate cell cycle progression/proliferation and deregulate cell-to-cell communication, which is associated with downregulation of proteins forming gap junctions, adherens junctions, and desmosomes (such as connexin 43, E-cadherin, β-catenin, and plakoglobin), as well as with reduced cell adhesion and inhibition of intercellular communication. At the same time, toxic AhR ligands may affect the activity of the signaling pathways contributing to regulation of liver progenitor cell activation and/or differentiation, such as downregulation of Wnt/β-catenin and TGF-β signaling, or upregulation of transcriptional targets of YAP/TAZ, the effectors of Hippo signaling pathway. These data illustrate the need to better understand the potential role of liver progenitors in the AhR-mediated liver carcinogenesis and tumor promotion.},

note = {Place: United States},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{kremserova_lung_2016,

title = {Lung Neutrophilia in Myeloperoxidase Deficient Mice during the Course of Acute Pulmonary Inflammation.},

author = {Silvie Kremserova and Tomas Perecko and Karel Soucek and Anna Klinke and Stephan Baldus and Jason P. Eiserich and Lukas Kubala},

doi = {10.1155/2016/5219056},

issn = {1942-0994 1942-0900},

year  = {2016},

date = {2016-01-01},

journal = {Oxidative medicine and cellular longevity},

volume = {2016},

pages = {5219056},

abstract = {Systemic inflammation accompanying diseases such as sepsis affects primarily lungs and induces their failure. This remains the most common cause of sepsis induced mortality. While neutrophils play a key role in pulmonary failure, the mechanisms remain incompletely characterized. We report that myeloperoxidase (MPO), abundant enzyme in neutrophil granules, modulates the course of acute pulmonary inflammatory responses induced by intranasal application of lipopolysaccharide. MPO deficient mice had significantly increased numbers of airway infiltrated neutrophils compared to wild-type mice during the whole course of lung inflammation. This was accompanied by higher levels of RANTES in bronchoalveolar lavage fluid from the MPO deficient mice. Other markers of lung injury and inflammation, which contribute to recruitment of neutrophils into the inflamed lungs, including total protein and other selected proinflammatory cytokines did not significantly differ in bronchoalveolar lavage fluid from the wild-type and the MPO deficient mice. Interestingly, MPO deficient neutrophils revealed a decreased rate of cell death characterized by phosphatidylserine surface expression. Collectively, the importance of MPO in regulation of pulmonary inflammation, independent of its putative microbicidal functions, can be potentially linked to MPO ability to modulate the life span of neutrophils and to affect accumulation of chemotactic factors at the inflammatory site.},

note = {Place: United States},

keywords = {Acute Disease, Acute Lung Injury/complications/genetics, Animals, Inborn Errors/*complications, Inbred C57BL, Knockout, Leukocyte Disorders/*complications/*genetics, Lipopolysaccharides, Male, metabolism, Mice, Neutrophils/*pathology, Peroxidase/deficiency/genetics, Pneumonia/chemically induced/*complications/genetics},

pubstate = {published},

tppubtype = {article}

}

@article{dvorak_exacerbation_2015,

title = {Exacerbation of substrate toxicity by IPTG in Escherichia coli BL21(DE3) carrying a synthetic metabolic pathway.},

author = {Pavel Dvorak and Lukas Chrast and Pablo I. Nikel and Radek Fedr and Karel Soucek and Miroslava Sedlackova and Radka Chaloupkova and Víctor Lorenzo and Zbynek Prokop and Jiri Damborsky},

doi = {10.1186/s12934-015-0393-3},

issn = {1475-2859},

year  = {2015},

date = {2015-12-01},

journal = {Microbial cell factories},

volume = {14},

pages = {201},

abstract = {BACKGROUND: Heterologous expression systems based on promoters inducible with isopropyl-β-D-1-thiogalactopyranoside (IPTG), e.g., Escherichia coli BL21(DE3) and cognate LacI(Q)/P(lacUV5)-T7 vectors, are commonly used for production of recombinant proteins and metabolic pathways. The applicability of such cell factories is limited by the complex physiological burden imposed by overexpression of the exogenous genes during a bioprocess. This burden originates from a combination of stresses that may include competition for the expression machinery, side-reactions due to the activity of the recombinant proteins, or the toxicity of their substrates, products and intermediates. However, the physiological impact of IPTG-induced conditional expression on the recombinant host under such harsh conditions is often overlooked. RESULTS: The physiological responses to IPTG of the E. coli BL21(DE3) strain and three different recombinants carrying a synthetic metabolic pathway for biodegradation of the toxic anthropogenic pollutant 1,2,3-trichloropropane (TCP) were investigated using plating, flow cytometry, and electron microscopy. Collected data revealed unexpected negative synergistic effect of inducer of the expression system and toxic substrate resulting in pronounced physiological stress. Replacing IPTG with the natural sugar effector lactose greatly reduced such stress, demonstrating that the effect was due to the original inducer's chemical properties. CONCLUSIONS: IPTG is not an innocuous inducer; instead, it exacerbates the toxicity of haloalkane substrate and causes appreciable damage to the E. coli BL21(DE3) host, which is already bearing a metabolic burden due to its content of plasmids carrying the genes of the synthetic metabolic pathway. The concentration of IPTG can be effectively tuned to mitigate this negative effect. Importantly, we show that induction with lactose, the natural inducer of P lac , dramatically lightens the burden without reducing the efficiency of the synthetic TCP degradation pathway. This suggests that lactose may be a better inducer than IPTG for the expression of heterologous pathways in E. coli BL21(DE3).},

note = {Place: England},

keywords = {Escherichia coli/*metabolism, Isopropyl Thiogalactoside/*adverse effects/genetics, Metabolic Engineering, Metabolic Networks and Pathways/*genetics},

pubstate = {published},

tppubtype = {article}

}

@article{slabakova_opposite_2015,

title = {Opposite regulation of MDM2 and MDMX expression in acquisition of mesenchymal phenotype in benign and cancer cells.},

author = {Eva Slabáková and Gvantsa Kharaishvili and Monika Smějová and Zuzana Pernicová and Tereza Suchánková and Ján Remšík and Stanislav Lerch and Nicol Straková and Jan Bouchal and Milan Král and Zoran Culig and Alois Kozubík and Karel Souček},

doi = {10.18632/oncotarget.5392},

issn = {1949-2553},

year  = {2015},

date = {2015-11-01},

journal = {Oncotarget},

volume = {6},

number = {34},

pages = {36156–36171},

abstract = {Plasticity of cancer cells, manifested by transitions between epithelial and mesenchymal phenotypes, represents a challenging issue in the treatment of neoplasias. Both epithelial-mesenchymal transition (EMT) and mesenchymal-epithelial transition (MET) are implicated in the processes of metastasis formation and acquisition of stem cell-like properties. Mouse double minute (MDM) 2 and MDMX are important players in cancer progression, as they act as regulators of p53, but their function in EMT and metastasis may be contradictory. Here, we show that the EMT phenotype in multiple cellular models and in clinical prostate and breast cancer samples is associated with a decrease in MDM2 and increase in MDMX expression. Modulation of EMT-accompanying changes in MDM2 expression in benign and transformed prostate epithelial cells influences their migration capacity and sensitivity to docetaxel. Analysis of putative mechanisms of MDM2 expression control demonstrates that in the context of defective p53 function, MDM2 expression is regulated by EMT-inducing transcription factors Slug and Twist. These results provide an alternative context-specific role of MDM2 in EMT, cell migration, metastasis, and therapy resistance.},

note = {Place: United States},

keywords = {Animals, Breast Neoplasms/genetics/*metabolism/pathology, Cell Cycle Proteins, Cell Line, Epithelial-Mesenchymal Transition, Epithelial-Mesenchymal Transition/*physiology, Female, Heterografts, Humans, Male, MDM2/MDMX, Mice, Nuclear Proteins/*biosynthesis, Nude, Phenotype, prostate/breast cancer, Prostatic Neoplasms/genetics/*metabolism/pathology, Proto-Oncogene Proteins c-mdm2/*biosynthesis, Proto-Oncogene Proteins/*biosynthesis, Snai2/Slug, Transfection, Tumor, TWIST},

pubstate = {published},

tppubtype = {article}

}

@article{kratochvilova_tumor_2015,

title = {Tumor suppressor candidate 3 (TUSC3) prevents the epithelial-to-mesenchymal transition and inhibits tumor growth by modulating the endoplasmic reticulum stress response in ovarian cancer cells.},

author = {Kateřina Kratochvílová and Peter Horak and Milan Ešner and Karel Souček and Dietmar Pils and Mariam Anees and Erwin Tomasich and František Dráfi and Veronika Jurtíková and Aleš Hampl and Michael Krainer and Petr Vaňhara},

doi = {10.1002/ijc.29502},

issn = {1097-0215 0020-7136},

year  = {2015},

date = {2015-09-01},

journal = {International journal of cancer},

volume = {137},

number = {6},

pages = {1330–1340},

abstract = {Ovarian cancer is one of the most common malignancies in women and contributes greatly to cancer-related deaths. Tumor suppressor candidate 3 (TUSC3) is a putative tumor suppressor gene located at chromosomal region 8p22, which is often lost in epithelial cancers. Epigenetic silencing of TUSC3 has been associated with poor prognosis, and hypermethylation of its promoter provides an independent biomarker of overall and disease-free survival in ovarian cancer patients. TUSC3 is localized to the endoplasmic reticulum in an oligosaccharyl tranferase complex responsible for the N-glycosylation of proteins. However, the precise molecular role of TUSC3 in ovarian cancer remains unclear. In this study, we establish TUSC3 as a novel ovarian cancer tumor suppressor using a xenograft mouse model and demonstrate that loss of TUSC3 alters the molecular response to endoplasmic reticulum stress and induces hallmarks of the epithelial-to-mesenchymal transition in ovarian cancer cells. In summary, we have confirmed the tumor-suppressive function of TUSC3 and identified the possible mechanism driving TUSC3-deficient ovarian cancer cells toward a malignant phenotype.},

note = {Place: United States},

keywords = {Animals, Cell Line, Endoplasmic Reticulum Stress, Endoplasmic Reticulum Stress/*genetics, Epithelial-Mesenchymal Transition/*genetics, epithelial-to-mesenchymal transition, Female, Genes, Heterografts, Humans, Inbred NOD, Membrane Proteins/*genetics, Mice, N33, ovarian cancer, Ovarian Neoplasms/*genetics, SCID, Tumor, Tumor Suppressor, Tumor Suppressor Proteins/*genetics, Tumor Suppressor/physiology, TUSC3},

pubstate = {published},

tppubtype = {article}

}

@article{svobodova_aryl_2015,

title = {The aryl hydrocarbon receptor-dependent disruption of contact inhibition in rat liver WB-F344 epithelial cells is linked with induction of survivin, but not with inhibition of apoptosis.},

author = {Jana Svobodová and Markéta Kabátková and Lenka Šmerdová and Petra Brenerová and Zdeněk Dvořák and Miroslav Machala and Jan Vondráček},

doi = {10.1016/j.tox.2015.04.001},

issn = {1879-3185 0300-483X},

year  = {2015},

date = {2015-07-01},

journal = {Toxicology},

volume = {333},

pages = {37–44},

abstract = {Inhibition of apoptosis by the ligands of the aryl hydrocarbon receptor (AhR) has been proposed to play a role in their tumor promoting effects on liver parenchymal cells. However, little is presently known about the impact of toxic AhR ligands, such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on apoptosis in other liver cell types, such as in liver epithelial/progenitor cells. In the present study, we focused on the effects of TCDD on apoptosis regulation in a model of liver progenitor cells, rat WB-F344 cell line, during the TCDD-elicited release from contact inhibition. The stimulation of cell proliferation in this cell line was associated with deregulated expression of a number of genes known to be under transcriptional control of the Hippo signaling pathway, a principal regulatory pathway involved in contact inhibition of cell proliferation. Interestingly, we found that mRNA and protein levels of survivin, a known Hippo target, which plays a role both in cell division and inhibition of apoptosis, were significantly up-regulated in rat liver epithelial cell model, as well as in undifferentiated human liver HepaRG cells. Using the short interfering RNA-mediated knockdown, we confirmed that survivin plays a central role in cell division of WB-F344 cells. When evaluating the effects of TCDD on apoptosis induction by camptothecin, a genotoxic topoisomerase I inhibitor, we observed that the pre-treatment of WB-F344 cells with TCDD increased number of cells with apoptotic nuclear morphology, and it potentiated cleavage of both caspase-3 and poly(ADP-ribose) polymerase I. This indicated that despite the observed up-regulation of survivin, apoptosis induced by the genotoxin was potentiated in the model of rat liver progenitor cells. The present results indicate that, unlike in hepatocytes, AhR agonists may not prevent induction of apoptosis elicited by DNA-damaging agents in a model of rat liver progenitor cells.},

note = {Place: Ireland},

keywords = {AhR, Animals, Apoptosis, Apoptosis/*drug effects, Aryl Hydrocarbon/*agonists/metabolism, Basic Helix-Loop-Helix Transcription Factors/*agonists/metabolism, BIRC5/survivin, Camptothecin/*toxicity, Caspase 3/metabolism, Cell Line, Contact inhibition, Contact Inhibition/*drug effects, Epithelial Cells/*drug effects/metabolism/pathology, Genetic/drug effects, Hippo signaling, Humans, Inbred F344, Inhibitor of Apoptosis Proteins/genetics/metabolism, Liver/*drug effects/metabolism/pathology, Microtubule-Associated Proteins/genetics/*metabolism, Poly (ADP-Ribose) Polymerase-1, Poly(ADP-ribose) Polymerases/metabolism, Polychlorinated Dibenzodioxins/*toxicity, Rats, Receptors, RNA Interference, Signal Transduction/drug effects, Survivin, TCDD, Time Factors, Topoisomerase I Inhibitors/*toxicity, Transcription, Transfection, Up-Regulation},

pubstate = {published},

tppubtype = {article}

}

@article{kabatkova_inhibition_2015,

title = {Inhibition of β-catenin signalling promotes DNA damage elicited by benzo[a]pyrene in a model of human colon cancer cells via CYP1 deregulation.},

author = {Markéta Kabátková and Ondřej Zapletal and Zuzana Tylichová and Jiří Neča and Miroslav Machala and Alena Milcová and Jan Topinka and Alois Kozubík and Jan Vondráček},

doi = {10.1093/mutage/gev019},

issn = {1464-3804 0267-8357},

year  = {2015},

date = {2015-07-01},

journal = {Mutagenesis},

volume = {30},

number = {4},

pages = {565–576},

abstract = {Deregulation of Wnt/β-catenin signalling plays an important role in the pathogenesis of colorectal cancer. Interestingly, this pathway has been recently implicated in transcriptional control of cytochrome P450 (CYP) family 1 enzymes, which are responsible for bioactivation of a number of dietary carcinogens. In the present study, we investigated the impact of inhibition of Wnt/β-catenin pathway on metabolism and genotoxicity of benzo[a]pyrene (BaP), a highly mutagenic polycyclic aromatic hydrocarbon and an efficient ligand of the aryl hydrocarbon receptor, which is known as a primary regulator of CYP1 expression, in cellular models derived from colorectal tumours. We observed that a synthetic inhibitor of β-catenin, JW74, significantly increased formation of BaP-induced DNA adducts in both colorectal adenoma and carcinoma-derived cell lines. Using the short interfering RNA (siRNA) targeting β-catenin, we then found that β-catenin knockdown in HCT116 colon carcinoma cells significantly enhanced formation of covalent DNA adducts by BaP and histone H2AX phosphorylation, as detected by (32)P-postlabelling technique and immunocytochemistry, respectively, and it also induced expression of DNA damage response genes, such as CDKN1A or DDB2. The increased formation of DNA adducts formed by BaP upon β-catenin knockdown corresponded with enhanced production of major BaP metabolites, as well as with an increased expression/activity of CYP1 enzymes. Finally, using siRNA-mediated knockdown of CYP1A1, we confirmed that this enzyme plays a major role in formation of BaP-induced DNA adducts in HCT116 cells. Taken together, the present results indicated that the siRNA-mediated inhibition of β-catenin signalling, which is aberrantly activated in a majority of colorectal cancers, modulated genotoxicity of dietary carcinogen BaP in colon cell model in vitro, via a mechanism involving up-regulation of CYP1 expression and activity.},

note = {Place: England},

keywords = {*DNA Damage, Apoptosis, Aryl Hydrocarbon/genetics/metabolism, Benzo(a)pyrene/*adverse effects, beta Catenin/*antagonists & inhibitors/genetics/metabolism, Blotting, Carcinogens, Cell Proliferation, Colonic Neoplasms/drug therapy/*etiology/*pathology, Cultured, Cytochrome P-450 CYP1A1/antagonists & inhibitors/genetics/*metabolism, DNA Adducts/*adverse effects, Environmental/adverse effects, Enzymologic/*drug effects, Gene Expression Regulation, Humans, Immunoenzyme Techniques, Messenger/genetics, Neoplastic/*drug effects, Real-Time Polymerase Chain Reaction, Receptors, Reverse Transcriptase Polymerase Chain Reaction, RNA, Small Interfering/genetics, Tumor Cells, Western},

pubstate = {published},

tppubtype = {article}

}

@article{nahta_mechanisms_2015,

title = {Mechanisms of environmental chemicals that enable the cancer hallmark of evasion of growth suppression.},

author = {Rita Nahta and Fahd Al-Mulla and Rabeah Al-Temaimi and Amedeo Amedei and Rafaela Andrade-Vieira and Sarah N. Bay and Dustin G. Brown and Gloria M. Calaf and Robert C. Castellino and Karine A. Cohen-Solal and Annamaria Colacci and Nichola Cruickshanks and Paul Dent and Riccardo Di Fiore and Stefano Forte and Gary S. Goldberg and Roslida A. Hamid and Harini Krishnan and Dale W. Laird and Ahmed Lasfar and Paola A. Marignani and Lorenzo Memeo and Chiara Mondello and Christian C. Naus and Richard Ponce-Cusi and Jayadev Raju and Debasish Roy and Rabindra Roy and Elizabeth P. Ryan and Hosni K. Salem and A. Ivana Scovassi and Neetu Singh and Monica Vaccari and Renza Vento and Jan Vondráček and Mark Wade and Jordan Woodrick and William H. Bisson},

doi = {10.1093/carcin/bgv028},

issn = {1460-2180 0143-3334},

year  = {2015},

date = {2015-06-01},

journal = {Carcinogenesis},

volume = {36 Suppl 1},

number = {Suppl 1},

pages = {S2–18},

abstract = {As part of the Halifax Project, this review brings attention to the potential effects of environmental chemicals on important molecular and cellular regulators of the cancer hallmark of evading growth suppression. Specifically, we review the mechanisms by which cancer cells escape the growth-inhibitory signals of p53, retinoblastoma protein, transforming growth factor-beta, gap junctions and contact inhibition. We discuss the effects of selected environmental chemicals on these mechanisms of growth inhibition and cross-reference the effects of these chemicals in other classical cancer hallmarks.},

note = {Place: England},

keywords = {Animals, Environmental Exposure/*adverse effects, Hazardous Substances/*adverse effects, Humans, Neoplasms/*chemically induced/*etiology, Signal Transduction/drug effects},

pubstate = {published},

tppubtype = {article}

}

@article{larsson_consensus_2015,

title = {Consensus toxicity factors for polychlorinated dibenzo-p-dioxins, dibenzofurans, and biphenyls combining in silico models and extensive in vitro screening of AhR-mediated effects in human and rodent cells.},

author = {Malin Larsson and Martin Berg and Petra Brenerová and Majorie B. M. Duursen and Karin I. Ede and Christiane Lohr and Sandra Luecke-Johansson and Miroslav Machala and Sylke Neser and Kateřina Pěnčíková and Lorenz Poellinger and Dieter Schrenk and Simona Strapáčová and Jan Vondráček and Patrik L. Andersson},

doi = {10.1021/tx500434j},

issn = {1520-5010 0893-228X},

year  = {2015},

date = {2015-04-01},

journal = {Chemical research in toxicology},

volume = {28},

number = {4},

pages = {641–650},

abstract = {Consensus toxicity factors (CTFs) were developed as a novel approach to establish toxicity factors for risk assessment of dioxin-like compounds (DLCs). Eighteen polychlorinated dibenzo-p-dioxins, dibenzofurans (PCDD/Fs), and biphenyls (PCBs) with assigned World Health Organization toxic equivalency factors (WHO-TEFs) and two additional PCBs were screened in 17 human and rodent bioassays to assess their induction of aryl hydrocarbon receptor-related responses. For each bioassay and compound, relative effect potency values (REPs) compared to 2,3,7,8-tetrachlorodibenzo-p-dioxin were calculated and analyzed. The responses in the human and rodent cell bioassays generally differed. Most notably, the human cell models responded only weakly to PCBs, with 3,3',4,4',5-pentachlorobiphenyl (PCB126) being the only PCB that frequently evoked sufficiently strong responses in human cells to permit us to calculate REP values. Calculated REPs for PCB126 were more than 30 times lower than the WHO-TEF value for PCB126. CTFs were calculated using score and loading vectors from a principal component analysis to establish the ranking of the compounds and, by rescaling, also to provide numerical differences between the different congeners corresponding to the TEF scheme. The CTFs were based on rat and human bioassay data and indicated a significant deviation for PCBs but also for certain PCDD/Fs from the WHO-TEF values. The human CTFs for 2,3,4,7,8-pentachlorodibenzofuran, 1,2,3,4,7,8-hexachlorodibenzofuran, 1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin, and 1,2,3,4,7,8,9-heptachlorodibenzofuran were up to 10 times greater than their WHO-TEF values. Quantitative structure-activity relationship models were used to predict CTFs for untested WHO-TEF compounds, suggesting that the WHO-TEF value for 1,2,3,7,8-pentachlorodibenzofuran could be underestimated by an order of magnitude for both human and rodent models. Our results indicate that the CTF approach provides a powerful tool for condensing data from batteries of screening tests using compounds with similar mechanisms of action, which can be used to improve risk assessment of DLCs.},

note = {Place: United States},

keywords = {Animals, Aryl Hydrocarbon/*physiology, Benzofurans/chemistry/*toxicity, Computer Simulation, Dibenzofurans, Humans, In Vitro Techniques, Polychlorinated, Polychlorinated Biphenyls/chemistry/*toxicity, Polychlorinated Dibenzodioxins/*analogs & derivatives/chemistry/toxicity, Quantitative Structure-Activity Relationship, Rats, Receptors, Rodentia},

pubstate = {published},

tppubtype = {article}

}

@article{palkova_aryl_2015,

title = {The aryl hydrocarbon receptor-mediated and genotoxic effects of fractionated extract of standard reference diesel exhaust particle material in pulmonary, liver and prostate cells.},

author = {Lenka Pálková and Jan Vondráček and Lenka Trilecová and Miroslav Ciganek and Kateřina Pěnčíková and Jiří Neča and Alena Milcová and Jan Topinka and Miroslav Machala},

doi = {10.1016/j.tiv.2014.12.002},

issn = {1879-3177 0887-2333},

year  = {2015},

date = {2015-04-01},

journal = {Toxicology in vitro : an international journal published in association with BIBRA},

volume = {29},

number = {3},

pages = {438–448},

abstract = {Diesel exhaust particles (DEP) and the associated complex mixtures of organic pollutants, such as polycyclic aromatic hydrocarbons (PAHs), or their derivatives, have been suggested to exert deleterious effects on human health. We used a set of defined cellular models representing liver, lung and prostate tissues, in order to compare non-genotoxic and genotoxic effects of crude and fractionated extract of a standard reference DEP material - SRM 1650b. We focused on the aryl hydrocarbon receptor (AhR)-mediated activity, modulation of cell proliferation, formation of DNA adducts, oxidative DNA damage, and induction of DNA damage responses, including evaluation of apoptosis, and phosphorylation of p53 tumor suppressor and checkpoint kinases (Chk). Both PAHs and the polar aromatic compounds contributed to the AhR-mediated activity of DEP-associated organic pollutants. The principal identified AhR agonists included benzo[k]fluoranthene, indeno[1,2,3-c,d]pyrene, chrysene and several non-priority PAHs, including benzochrysenes and methylated PAHs. In contrast to PAHs, polar compounds contributed more significantly to overall formation of DNA adducts associated with phosphorylation of p53, Chk1 or Chk2, and partly with apoptosis. Therefore, more attention should be paid to identification of DEP-associated polar organic compounds, contributing to the AhR activation and cytotoxic/genotoxic effects of complex airborne mixtures of organic contaminants produced by diesel engines.},

note = {Place: England},

keywords = {Air Pollutants/*toxicity, Air pollution, Animals, Apoptosis, Apoptosis/drug effects, Aryl Hydrocarbon/*drug effects, Cell Cycle/drug effects, Cell Death/drug effects, Cell Proliferation, DNA adducts, DNA Damage, DNA damage response, Liver/*pathology, Lung/*pathology, Male, Mutagens/*toxicity, PAHs, Particulate Matter/*toxicity, Prostate/*pathology, Rats, Receptors, SRM 1650b, Vehicle Emissions/*toxicity},

pubstate = {published},

tppubtype = {article}

}

@article{kollar_flavonoid_2015,

title = {Flavonoid 4'-O-Methylkuwanon E from Morus alba Induces the Differentiation of THP-1 Human Leukemia Cells.},

author = {Peter Kollar and Tomáš Bárta and Stanislava Keltošová and Pavlína Trnová and Veronika Müller Závalová and Karel Šmejkal and Jan Hošek and Radek Fedr and Karel Souček and Aleš Hampl},

doi = {10.1155/2015/251895},

issn = {1741-427X 1741-4288},

year  = {2015},

date = {2015-01-01},

journal = {Evidence-based complementary and alternative medicine : eCAM},

volume = {2015},

pages = {251895},

abstract = {Aims. In this work we studied cytodifferentiation effects of newly characterized prenyl flavonoid 4'-O-methylkuwanon E (4ME) isolated from white mulberry (Morus alba L.). Main Methods. Cell growth and viability were measured by dye exclusion assay; cell cycle and surface antigen CD11b were monitored by flow cytometry. For the cytodifferentiation of cells the NBT reduction assay was employed. Regulatory proteins were assessed by western blotting. Key Findings. 4ME induced dose-dependent growth inhibition of THP-1 cells, which was not accompanied by toxic effect. Inhibition of cells proliferation caused by 4ME was associated with the accumulation in G1 phase and with downregulation of hyperphosphorylated pRb. Treatment with 4ME led to significant induction of NBT-reducing activity of PMA stimulated THP-1 cells and upregulation expression of differentiation-associated surface antigen CD11b. Our results suggest that monocytic differentiation induced by 4ME is connected with up-regulation of p38 kinase activity. Significance. Our study provides the first evidence that 4ME induces the differentiation of THP-1 human monocytic leukemia cells and thus is a potential cytodifferentiating anticancer agent.},

note = {Place: United States},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{kabatkova_interactive_2015,

title = {Interactive effects of inflammatory cytokine and abundant low-molecular-weight PAHs on inhibition of gap junctional intercellular communication, disruption of cell proliferation control, and the AhR-dependent transcription.},

author = {Markéta Kabátková and Jana Svobodová and Kateřina Pěnčíková and Dilshad Shaik Mohatad and Lenka Šmerdová and Alois Kozubík and Miroslav Machala and Jan Vondráček},

doi = {10.1016/j.toxlet.2014.09.023},

issn = {1879-3169 0378-4274},

year  = {2015},

date = {2015-01-01},

journal = {Toxicology letters},

volume = {232},

number = {1},

pages = {113–121},

abstract = {Polycyclic aromatic hydrocarbons (PAHs) with lower molecular weight exhibit lesser genotoxicity and carcinogenicity than highly carcinogenic PAHs with a higher number of benzene rings. Nevertheless, they elicit specific effects linked with tumor promotion, such as acute inhibition of gap junctional intercellular communication (GJIC). Although inflammatory reaction may alter bioactivation and toxicity of carcinogenic PAHs, little is known about the impact of pro-inflammatory cytokines on toxic effects of the low-molecular-weight PAHs. Here, we investigated the impact of a pro-inflammatory cytokine, tumor necrosis factor-α (TNF-α), on the effects associated with tumor promotion and with induction of the aryl hydrocarbon receptor (AhR)-dependent gene expression in rat liver epithelial cells. We found that a prolonged incubation with TNF-α induced a down-regulation of GJIC, associated with reduced expression of connexin 43 (Cx43), a major connexin isoform found in liver epithelial cells. The Cx43 down-regulation was partly mediated by the activity of the mitogen-activated protein (MAP) p38 kinase. Independently of GJIC modulation, or p38 activation, TNF-α potentiated the AhR-dependent proliferative effect of a model low-molecular-weight PAH, fluoranthene, on contact-inhibited cells. In contrast, this pro-inflammatory cytokine repressed the fluoranthene-induced expression of a majority of model AhR gene targets, such as Cyp1a1, Ahrr or Tiparp. The results of the present study indicate that inflammatory reaction may differentially modulate various toxic effects of low-molecular-weight PAHs; the exposure to pro-inflammatory cytokines may both strengthen (inhibition of GJIC, disruption of contact inhibition) and repress (expression of a majority of AhR-dependent genes) their impact on toxic endpoints associated with carcinogenesis.},

note = {Place: Netherlands},

keywords = {Animals, Aryl hydrocarbon receptor, Aryl Hydrocarbon/*agonists/genetics/metabolism, Basic Helix-Loop-Helix Transcription Factors/*agonists/genetics/metabolism, Cell Communication/*drug effects, Cell Line, Cell Proliferation, Cell Proliferation/*drug effects, Cell Transformation, Connexin 43/genetics/metabolism, Dose-Response Relationship, Drug, Enzyme Activation, Epithelial Cells/*drug effects/metabolism/pathology, Fluorenes/*toxicity, Gap junctions, Gap Junctions/*drug effects/metabolism/pathology, Gene Expression Regulation/drug effects, Genetic/*drug effects, Inflammation, Inflammation/chemically induced/genetics/metabolism/pathology, Liver Neoplasms/chemically induced/metabolism/pathology, Liver/*drug effects/metabolism/pathology, Molecular Weight, Neoplastic/chemically induced/metabolism/pathology, p38 Mitogen-Activated Protein Kinases/metabolism, PAHs, Rats, Receptors, Signal Transduction/drug effects, Time Factors, Transcription, Tumor Necrosis Factor-alpha/*toxicity},

pubstate = {published},

tppubtype = {article}

}

@article{libalova_analysis_2014,

title = {Analysis of gene expression changes in A549 cells induced by organic compounds from respirable air particles.},

author = {Helena Líbalová and Simona Krčková and Kateřina Uhlířová and Jiří Kléma and Miroslav Ciganek and Pavel Jr Rössner and Radim J. Šrám and Jan Vondráček and Miroslav Machala and Jan Topinka},

doi = {10.1016/j.mrfmmm.2014.10.002},

issn = {1873-135X 0027-5107},

year  = {2014},

date = {2014-12-01},

journal = {Mutation research},

volume = {770},

pages = {94–105},

abstract = {A number of toxic effects of respirable ambient air particles (genotoxic effects, inflammation, oxidative damage) have been attributed to organic compounds bound onto the particle surface. In this study, we analyzed global gene expression changes caused by the extractable organic matters (EOMs) from respirable airborne particles <2.5μm (PM2.5), collected at 3 localities from heavily polluted areas of the Czech Republic and a control locality with low pollution levels, in human lung epithelial A549 cells. Although the sampled localities differed in both extent and sources of air pollution, EOMs did not induce substantially different gene expression profiles. The number of transcripts deregulated in A549 cells treated with the lowest EOM concentration (10μg/ml) ranged from 65 to 85 in 4 sampling localities compared to the number of transcripts deregulated after 30μg/ml and 60μg/ml of EOMs, which ranged from 90 to 109, and from 149 to 452, respectively. We found numerous commonly deregulated genes and pathways related to activation of the aryl hydrocarbon receptor (AhR) and metabolism of xenobiotics and endogenous compounds. We further identified deregulation of expression of the genes involved in pro-inflammatory processes, oxidative stress response and in cancer and developmental pathways, such as TGF-β and Wnt signaling pathways. No cell cycle arrest, DNA repair or pro-apoptotic responses were identified at the transcriptional level after the treatment of A549 cells with EOMs. In conclusion, numerous processes and pathways deregulated in response to EOMs suggest a significant role of activated AhR. Interestingly, we did not observe substantial gene expression changes related to DNA damage response, possibly due to the antagonistic effect of non-genotoxic EOM components. Moreover, a comparison of EOM effects with other available data on modulation of global gene expression suggests possible overlap among the effects of PM2.5, EOMs and various types of AhR agonists.},

note = {Place: Netherlands},

keywords = {A549 Cells, Adenocarcinoma of Lung, Adenocarcinoma/genetics/pathology, Ah receptor, Cultured, gene expression profile, Gene Expression Profiling, Gene Expression Regulation, Gene Expression/*drug effects, Humans, Lung Neoplasms/genetics/pathology, Microarray Analysis, Neoplastic/drug effects, Organic Chemicals/*pharmacology, PAHs, Particulate Matter/*pharmacology, PM2.5, Respiratory Mucosa/drug effects/metabolism, Signal Transduction/drug effects/genetics, Tumor Cells},

pubstate = {published},

tppubtype = {article}

}

@article{smerdova_upregulation_2014,

title = {Upregulation of CYP1B1 expression by inflammatory cytokines is mediated by the p38 MAP kinase signal transduction pathway.},

author = {Lenka Smerdová and Jana Šmerdová and Markéta Kabátková and Jiří Kohoutek and Dalibor Blažek and Miroslav Machala and Jan Vondráček},

doi = {10.1093/carcin/bgu190},

issn = {1460-2180 0143-3334},

year  = {2014},

date = {2014-11-01},

journal = {Carcinogenesis},

volume = {35},

number = {11},

pages = {2534–2543},

abstract = {Cytochrome P450 1B1 (CYP1B1) is an enzyme that has a unique tumor-specific pattern of expression and is capable of bioactivating a wide range of carcinogenic compounds. We have reported previously that coordinated upregulation of CYP1B1 by inflammatory cytokines, such as tumor necrosis factor-α (TNF-α) and the aryl hydrocarbon receptor ligands, may increase bioactivation of promutagens, such as benzo[a]pyrene (BaP) in epithelial cells. Here, we extend those studies by describing a novel mechanism participating in the regulation of CYP1B1 expression, which involves activation of the p38 mitogen-activated protein kinase (p38) and mitogen- and stress-activated protein kinase 1 (MSK1). Using inhibitors of p38 and MSKs, as well as mouse embryonic cells derived from p38α-deficient and MSK1/2 double knockout mice, we show here that TNF-α potentiates CYP1B1 upregulation via the p38/MSK1 kinase cascade. Effects of this inflammatory cytokine on CYP1B1 expression further involve the positive transcription elongation factor b (P-TEFb). The inhibition of the P-TEFb subunit, cyclin-dependent kinase 9 (CDK9), which phosphorylates RNA polymerase II (RNAPII), prevented the enhanced CYP1B1 induction by a combination of BaP and inflammatory cytokine. Furthermore, using chromatin immunoprecipitation assays, we found that cotreatment of epithelial cells with TNF-α and BaP resulted in enhanced recruitment of both CDK9 and RNAPII to the Cyp1b1 gene promoter. Overall, these results have implications concerning the contribution of inflammatory factors to carcinogenesis, since enhanced CYP1B1 induction during inflammation may alter metabolism of exogenous carcinogens, as well as endogenous CYP1B1 substrates playing role in tumor development.},

note = {Place: England},

keywords = {Animals, Carcinogenesis/drug effects/*genetics, Carcinogens/toxicity, Cyclin-Dependent Kinase 9/genetics, Cytochrome P-450 CYP1B1/*biosynthesis/genetics, Cytokines/metabolism, Gene Expression Regulation, Humans, Mice, Neoplasms/chemically induced/*genetics/pathology, Neoplastic/drug effects, p38 Mitogen-Activated Protein Kinases/antagonists & inhibitors/*genetics/metabolism, Positive Transcriptional Elongation Factor B/genetics, RNA Polymerase II/genetics, Signal Transduction/drug effects, Tumor Necrosis Factor-alpha/metabolism},

pubstate = {published},

tppubtype = {article}

}

@article{uhlik_bacterial_2014,

title = {Bacterial acquisition of hexachlorobenzene-derived carbon in contaminated soil.},

author = {Ondrej Uhlik and Michal Strejcek and Jan Vondracek and Lucie Musilova and Jakub Ridl and Petra Lovecka and Tomas Macek},

doi = {10.1016/j.chemosphere.2014.04.110},

issn = {1879-1298 0045-6535},

year  = {2014},

date = {2014-10-01},

journal = {Chemosphere},

volume = {113},

pages = {141–145},

abstract = {Pesticides are a class of xenobiotics intentionally released into the environment. Hexachlorobenzene (HCB) was used as a fungicide from 1945, leaving behind many contaminated sites. Very few studies have examined the biodegradation of HCB or the fate of HCB-derived carbon. Here we report that certain bacterial populations are capable of deriving carbon from HCB in contaminated soil under aerobic conditions. These populations are primarily Proteobacteria, including Methylobacterium and Pseudomonas, which predominated as detected by stable isotope probing (SIP) and 16S rRNA gene amplicon pyrosequencing. Due to the nature of SIP, which can be used as a functional method solely for assimilatory processes, it is not possible to elucidate whether these populations metabolized directly HCB or intermediates of its metabolism produced by different populations. The possibility exists that HCB is degraded via the formation of pentachlorophenol (PCP), which is further mineralized. With this in mind, we designed primers to amplify PCP 4-monooxygenase-coding sequences based on the available pcpB gene sequence from Methylobacterium radiotolerans JCM 2831. Based on 16S rRNA gene analysis, organisms closely related to this strain were detected in (13)C-labeled DNA. Using the designed primers, we were able to amplify pcpB genes in both total community DNA and (13)C-DNA. This indicates that HCB might be transformed into PCP before it gets assimilated. In summary, this study is the first report on which bacterial populations benefit from carbon originating in the pesticide HCB in a contaminated soil.},

note = {Place: England},

keywords = {*Soil Microbiology, 16S rRNA genes, 16S/genetics, Amplicon pyrosequencing, Biodegradation, Bioremediation, Carbon Isotopes/metabolism, Czech Republic, DNA, DNA Primers, Environmental, Hexachlorobenzene/chemistry/*metabolism, Isotope Labeling, Methylobacterium/*metabolism, Mixed Function Oxygenases/metabolism, Molecular Structure, Pentachlorophenol 4-monooxygenase, Pentachlorophenol/chemistry/metabolism, Pesticides, Pseudomonas/*metabolism, Real-Time Polymerase Chain Reaction, Ribosomal, RNA, Sequence Analysis, Soil Pollutants/*metabolism, Stable isotope probing},

pubstate = {published},

tppubtype = {article}

}

@article{ghorbanzadeh_vitro_2014,

title = {In vitro and in silico derived relative effect potencies of ah-receptor-mediated effects by PCDD/Fs and PCBs in rat, mouse, and guinea pig CALUX cell lines.},

author = {Mehdi Ghorbanzadeh and Karin I. Ede and Malin Larsson and Majorie B. M. Duursen and Lorenz Poellinger and Sandra Lücke-Johansson and Miroslav Machala and Kateřina Pěnčíková and Jan Vondráček and Martin Berg and Michael S. Denison and Tine Ringsted and Patrik L. Andersson},

doi = {10.1021/tx5001255},

issn = {1520-5010 0893-228X},

year  = {2014},

date = {2014-07-01},

journal = {Chemical research in toxicology},

volume = {27},

number = {7},

pages = {1120–1132},

abstract = {For a better understanding of species-specific relative effect potencies (REPs), responses of dioxin-like compounds (DLCs) were assessed. REPs were calculated using chemical-activated luciferase gene expression assays (CALUX) derived from guinea pig, rat, and mouse cell lines. Almost all 20 congeners tested in the rodent cell lines were partial agonists and less efficacious than 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). For this reason, REPs were calculated for each congener using concentrations at which 20% of the maximal TCDD response was reached (REP20TCDD). REP20TCDD values obtained for PCDD/Fs were comparable with their toxic equivalency factors assigned by the World Health Organization (WHO-TEF), while those for PCBs were in general lower than the WHO-TEF values. Moreover, the guinea pig cell line was the most sensitive as indicated by the 20% effect concentrations of TCDD of 1.5, 5.6, and 11.0 pM for guinea pig, rat, and mouse cells, respectively. A similar response pattern was observed using multivariate statistical analysis between the three CALUX assays and the WHO-TEFs. The mouse assay showed minor deviation due to higher relative induction potential for 2,3,7,8-tetrachlorodibenzofuran and 2,3,4,6,7,8-hexachlorodibenzofuran and lower for 1,2,3,4,6,7,8-heptachlorodibenzofuran and 3,3',4,4',5-pentachlorobiphenyl (PCB126). 2,3,7,8-Tetrachlorodibenzofuran was more than two times more potent in the mouse assay as compared with that of rat and guinea pig cells, while measured REP20TCDD for PCB126 was lower in mouse cells (0.05) as compared with that of the guinea pig (0.2) and rat (0.07). In order to provide REP20TCDD values for all WHO-TEF assigned compounds, quantitative structure-activity relationship (QSAR) models were developed. The QSAR models showed that specific electronic properties and molecular surface characteristics play important roles in the AhR-mediated response. In silico derived REP20TCDD values were generally consistent with the WHO-TEFs with a few exceptions. The QSAR models indicated that, e.g., 1,2,3,7,8-pentachlorodibenzofuran and 1,2,3,7,8,9-hexachlorodibenzofuran were more potent than given by their assigned WHO-TEF values, and the non-ortho PCB 81 was predicted, based on the guinea-pig model, to be 1 order of magnitude above its WHO-TEF value. By combining in vitro and in silico approaches, REPs were established for all WHO-TEF assigned compounds (except OCDD), which will provide future guidance in testing AhR-mediated responses of DLCs and to increase our understanding of species variation in AhR-mediated effects.},

note = {Place: United States},

keywords = {Animals, Aryl Hydrocarbon/agonists/*metabolism, Benzofurans/*pharmacology, Biological, Biological Assay, Cell Line, Computer Simulation, Dibenzofurans, Dose-Response Relationship, Drug, Guinea Pigs, Luciferases/metabolism, Mice, Models, Polychlorinated, Polychlorinated Biphenyls/*pharmacology, Polychlorinated Dibenzodioxins/*analogs & derivatives/pharmacology, Quantitative Structure-Activity Relationship, Rats, Receptors, Tumor},

pubstate = {published},

tppubtype = {article}

}

@article{pernicova_role_2014,

title = {The role of high cell density in the promotion of neuroendocrine transdifferentiation of prostate cancer cells.},

author = {Zuzana Pernicová and Eva Slabáková and Radek Fedr and Šárka Šimečková and Josef Jaroš and Tereza Suchánková and Jan Bouchal and Gvantsa Kharaishvili and Milan Král and Alois Kozubík and Karel Souček},

doi = {10.1186/1476-4598-13-113},

issn = {1476-4598},

year  = {2014},

date = {2014-05-01},

journal = {Molecular cancer},

volume = {13},

pages = {113},

abstract = {BACKGROUND: Tumor heterogeneity and the plasticity of cancer cells present challenges for effective clinical diagnosis and therapy. Such challenges are epitomized by neuroendocrine transdifferentiation (NED) and the emergence of neuroendocrine-like cancer cells in prostate tumors. This phenomenon frequently arises from androgen-depleted prostate adenocarcinoma and is associated with the development of castration-resistant prostate cancer and poor prognosis. RESULTS: In this study, we showed that NED was evoked in both androgen receptor (AR)-positive and AR-negative prostate epithelial cell lines by growing the cells to a high density. Androgen depletion and high-density cultivation were both associated with cell cycle arrest and deregulated expression of several cell cycle regulators, such as p27Kip1, members of the cyclin D protein family, and Cdk2. Dual inhibition of Cdk1 and Cdk2 using pharmacological inhibitor or RNAi led to modulation of the cell cycle and promotion of NED. We further demonstrated that the cyclic adenosine 3', 5'-monophosphate (cAMP)-mediated pathway is activated in the high-density conditions. Importantly, inhibition of cAMP signaling using a specific inhibitor of adenylate cyclase, MDL-12330A, abolished the promotion of NED by high cell density. CONCLUSIONS: Taken together, our results imply a new relationship between cell cycle attenuation and promotion of NED and suggest high cell density as a trigger for cAMP signaling that can mediate reversible NED in prostate cancer cells.},

note = {Place: England},

keywords = {*Cell Transdifferentiation/drug effects, Androgen/metabolism, Androgens/pharmacology, CDC2 Protein Kinase, Cell Count, Cell Cycle Checkpoints/drug effects, Cell Line, Cyclic AMP/metabolism, Cyclin-Dependent Kinase 2/metabolism, Cyclin-Dependent Kinases/metabolism, Epithelial Cells/drug effects/enzymology/pathology, Humans, Immunohistochemistry, Male, Neuroendocrine Cells/drug effects/*pathology, Prostatic Neoplasms/*pathology, Protein Kinase Inhibitors/pharmacology, Receptors, Signal Transduction/drug effects, Tumor},

pubstate = {published},

tppubtype = {article}

}

@article{jirik_blind_2014,

title = {Blind deconvolution in dynamic contrast-enhanced MRI and ultrasound.},

author = {Radovan Jiřík and Karel Souček and Martin Mézl and Michal Bartoš and Eva Dražanová and František Dráfi and Lucie Grossová and Jiří Kratochvíla and Ondřej Macíček and Kim Nylund and Aleš Hampl and Odd Helge Gilja and Torfinn Taxt and Zenon Jr Starčuk},

doi = {10.1109/EMBC.2014.6944569},

issn = {2694-0604 2375-7477},

year  = {2014},

date = {2014-01-01},

journal = {Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual International Conference},

volume = {2014},

pages = {4276–4279},

abstract = {This paper is focused on quantitative perfusion analysis using MRI and ultrasound. In both MRI and ultrasound, most approaches allow estimation of rate constants (Ktrans, kep for MRI) and indices (AUC, TTP) that are only related to the physiological perfusion parameters of a tissue (e.g. blood flow, vessel permeability) but do not allow their absolute quantification. Recent methods for quantification of these physiological perfusion parameters are shortly reviewed. The main problem of these methods is estimation of the arterial input function (AIF). This paper summarizes and extends the current blind-deconvolution approaches to AIF estimation. The feasibility of these methods is shown on a small preclinical study using both MRI and ultrasound.},

note = {Place: United States},

keywords = {Animals, Cell Line, Contrast Media/*pharmacokinetics, Experimental/diagnostic imaging/metabolism, Gadolinium DTPA/*pharmacokinetics, Humans, Inbred BALB C, Magnetic Resonance Imaging/methods, Mice, Neoplasm Transplantation, Neoplasms, Tissue Distribution, Tumor, Ultrasonography},

pubstate = {published},

tppubtype = {article}

}

@article{steinmetz_oncogene_2014,

title = {The oncogene EVI1 enhances transcriptional and biological responses of human myeloid cells to all-trans retinoic acid.},

author = {Birgit Steinmetz and Hubert Hackl and Eva Slabáková and Ilse Schwarzinger and Monika Smějová and Andreas Spittler and Itziar Arbesu and Medhat Shehata and Karel Souček and Rotraud Wieser},

doi = {10.4161/15384101.2014.946869},

issn = {1551-4005 1538-4101},

year  = {2014},

date = {2014-01-01},

journal = {Cell cycle (Georgetown, Tex.)},

volume = {13},

number = {18},

pages = {2931–2943},

abstract = {The product of the ecotropic virus integration site 1 (EVI1) gene, whose overexpression is associated with a poor prognosis in myeloid leukemias and some epithelial tumors, regulates gene transcription both through direct DNA binding and through modulation of the activity of other sequence specific transcription factors. Previous results from our laboratory have shown that EVI1 influenced transcription regulation in response to the myeloid differentiation inducing agent, all-trans retinoic acid (ATRA), in a dual manner: it enhanced ATRA induced transcription of the RARβ gene, but repressed the ATRA induction of the EVI1 gene itself. In the present study, we asked whether EVI1 would modulate the ATRA regulation of a larger number of genes, as well as biological responses to this agent, in human myeloid cells. U937 and HL-60 cells ectopically expressing EVI1 through retroviral transduction were subjected to microarray based gene expression analysis, and to assays measuring cellular proliferation, differentiation, and apoptosis. These experiments showed that EVI1 modulated the ATRA response of several dozens of genes, and in fact reinforced it in the vast majority of cases. A particularly strong synergy between EVI1 and ATRA was observed for GDF15, which codes for a member of the TGF-β superfamily of cytokines. In line with the gene expression results, EVI1 enhanced cell cycle arrest, differentiation, and apoptosis in response to ATRA, and knockdown of GDF15 counteracted some of these effects. The potential clinical implications of these findings are discussed.},

note = {Place: United States},

keywords = {*Oncogenes, acute myeloid leukemia, acute promyelocytic leukemia, all-trans retinoic acid, AML, APL, Apoptosis, Apoptosis/drug effects, Ar, ATRA, ATRA regulation, Cell Cycle, Cell Cycle Checkpoints/drug effects, Cell Differentiation/drug effects, dimethyl sulfoxide, DMSO, DNA-Binding Proteins/genetics/*metabolism, Down-Regulation/drug effects, Em, Epithelial Cells/drug effects/metabolism, Er, EVI1, EVI1 modulation, EVI1 regulation, false discovery rate, FBS, FC, FDR, fetal bovine serum, fold change, GDF15, Gene Expression Profiling, Gene Knockdown Techniques, Genetic/*drug effects, GFP, green fluorescent protein, Growth Differentiation Factor 15/genetics/metabolism, HL-60 Cells, Humans, mcoEvi1, MDS, MDS1 and EVI1 Complex Locus Protein, murine codon optimized Evi1, myelodysplastic syndrome, Myeloid Cells/drug effects/*metabolism, myeloid differentiation, penicillin streptomycin glutamine, Proto-Oncogenes/genetics, PSG, RAR, RARE, Real-Time Polymerase Chain Reaction, Reproducibility of Results, retinoic acid receptor, retinoic acid response element, SE, standard error, Transcription, Transcription Factors/genetics/*metabolism, Tretinoin/*pharmacology},

pubstate = {published},

tppubtype = {article}

}

@article{smerdova_inflammatory_2013,

title = {Inflammatory mediators accelerate metabolism of benzo[a]pyrene in rat alveolar type II cells: the role of enhanced cytochrome P450 1B1 expression.},

author = {Lenka Smerdová and Jiří Neča and Jana Svobodová and Jan Topinka and Jana Schmuczerová and Alois Kozubík and Miroslav Machala and Jan Vondráček},

doi = {10.1016/j.tox.2013.09.001},

issn = {1879-3185 0300-483X},

year  = {2013},

date = {2013-12-01},

journal = {Toxicology},

volume = {314},

number = {1},

pages = {30–38},

abstract = {Long-term deregulated inflammation represents one of the key factors contributing to lung cancer etiology. Previously, we have observed that tumor necrosis factor-α (TNF-α), a major pro-inflammatory cytokine, enhances genotoxicity of benzo[a]pyrene (B[a]P), a highly carcinogenic polycyclic aromatic hydrocarbon, in rat lung epithelial RLE-6TN cells, a model of alveolar type II cells. Therefore, we analyzed B[a]P metabolism in RLE-6TN cells under inflammatory conditions, simulated using either recombinant TNF-α, or a mixture of inflammatory mediators derived from activated alveolar macrophage cell line. Inflammatory conditions significantly accelerated BaP metabolism, as evidenced by decreased levels of both parent B[a]P and its metabolites. TNF-α altered production of the metabolites associated with dihydrodiol-epoxide and radical cation pathways of B[a]P metabolism, especially B[a]P-dihydrodiols, and B[a]P-diones. We then evaluated the role of cytochrome P450 1B1 (CYP1B1), which is strongly up-regulated in cells treated with B[a]P under inflammatory conditions, in the observed effects. The siRNA-mediated CYP1B1 knock-down increased levels of B[a]P and reduced formation of stable DNA adducts, thus confirming the essential role of CYP1B1 in B[a]P metabolism under inflammatory conditions. TNF-α also reduced expression of aldo-keto reductase 1C14, which may compete with CYP1B1 for B[a]P-7,8-dihydrodiol and divert it from the formation of ultimate B[a]P dihydrodiol epoxide. Together, the present data suggests that the CYP1B1-catalyzed metabolism of polycyclic aromatic hydrocarbons might contribute to their enhanced bioactivation and genotoxic effects under inflammatory conditions.},

note = {Place: Ireland},

keywords = {Animals, Aryl Hydrocarbon Hydroxylases/*biosynthesis/genetics, ATP Binding Cassette Transporter, Benzo(a)pyrene/*metabolism, Blotting, Cell Line, Conditioned, Culture Media, CYP1B1, Cytochrome P-450 CYP1B1, Cytokines/metabolism, DNA adducts, Inflammation, Inflammation Mediators/*pharmacology, metabolism, Oxidoreductases Acting on Aldehyde or Oxo Group Donors/biosynthesis/genetics, Polycyclic aromatic hydrocarbons, Pulmonary Alveoli/cytology/drug effects/*metabolism, Rats, Real-Time Polymerase Chain Reaction, RNA, Small Interfering, Subfamily B/biosynthesis/genetics, Tandem Mass Spectrometry, Transfection, Western},

pubstate = {published},

tppubtype = {article}

}

@article{prochazkova_aryl_2013,

title = {Aryl hydrocarbon receptor negatively regulates expression of the plakoglobin gene (jup).},

author = {Jiřina Procházková and Markéta Kabátková and Lenka Šmerdová and Jiří Pacherník and Dominika Sykorová and Jiří Kohoutek and Pavlína Šimečková and Eva Hrubá and Alois Kozubík and Miroslav Machala and Jan Vondráček},

doi = {10.1093/toxsci/kft110},

issn = {1096-0929},

year  = {2013},

date = {2013-08-01},

journal = {Toxicological sciences : an official journal of the Society of Toxicology},

volume = {134},

number = {2},

pages = {258–270},

abstract = {Plakoglobin is an important component of intercellular junctions, including both desmosomes and adherens junctions, which is known as a tumor suppressor. Although mutations in the plakoglobin gene (Jup) and/or changes in its protein levels have been observed in various disease states, including cancer progression or cardiovascular defects, the information about endogenous or exogenous stimuli orchestrating Jup expression is limited. Here we show that the aryl hydrocarbon receptor (AhR) may regulate Jup expression in a cell-specific manner. We observed a significant suppressive effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a model toxic exogenous activator of the AhR signaling, on Jup expression in a variety of experimental models derived from rodent tissues, including contact-inhibited rat liver progenitor cells (where TCDD induces cell proliferation), rat and mouse hepatoma cell models (where TCDD inhibits cell cycle progression), cardiac cells derived from the mouse embryonic stem cells, or cardiomyocytes isolated from neonatal rat hearts. The small interfering RNA (siRNA)-mediated knockdown of AhR confirmed its role in both basal and TCDD-deregulated Jup expression. The analysis of genomic DNA located textasciitilde2.5kb upstream of rat Jup gene revealed a presence of evolutionarily conserved AhR binding motifs, which were confirmed upon their cloning into luciferase reporter construct. The siRNA-mediated knockdown of Jup expression affected both proliferation and attachment of liver progenitor cells. The present data indicate that the AhR may contribute to negative regulation of Jup gene expression in rodent cellular models, which may affect cell adherence and proliferation.},

note = {Place: United States},

keywords = {Animals, Aryl hydrocarbon receptor, Aryl Hydrocarbon/*physiology, Base Sequence, cardiomyocytes., Cell Adhesion, Cell Line, Cell Proliferation, Cloning, desmosomes, dioxin, DNA Primers, Down-Regulation, gamma Catenin/*genetics, Gene Expression Regulation/*physiology, Genetic, Inbred F344, liver progenitor cells, Molecular, plakoglobin, Polychlorinated Dibenzodioxins/pharmacology, Promoter Regions, Rats, Real-Time Polymerase Chain Reaction, Receptors},

pubstate = {published},

tppubtype = {article}

}

@article{fedr_automatic_2013,

title = {Automatic cell cloning assay for determining the clonogenic capacity of cancer and cancer stem-like cells.},

author = {Radek Fedr and Zuzana Pernicová and Eva Slabáková and Nicol Straková and Jan Bouchal and Michal Grepl and Alois Kozubík and Karel Souček},

doi = {10.1002/cyto.a.22273},

issn = {1552-4930 1552-4922},

year  = {2013},

date = {2013-05-01},

journal = {Cytometry. Part A : the journal of the International Society for Analytical Cytology},

volume = {83},

number = {5},

pages = {472–482},

abstract = {The clonogenic assay is a well-established in vitro method for testing the survival and proliferative capability of cells. It can be used to determine the cytotoxic effects of various treatments including chemotherapeutics and ionizing radiation. However, this approach can also characterize cells with different phenotypes and biological properties, such as stem cells or cancer stem cells. In this study, we implemented a faster and more precise method for assessing the cloning efficiency of cancer stem-like cells that were characterized and separated using a high-speed cell sorter. Cell plating onto a microplate using an automatic cell deposition unit was performed in a single-cell or dilution rank mode by the fluorescence-activated cell sorting method. We tested the new automatic cell-cloning assay (ACCA) on selected cancer cell lines and compared it with the manual approach. The obtained results were also compared with the results of the limiting dilution assay for different cell lines. We applied the ACCA to analyze the cloning capacity of different subpopulations of prostate and colon cancer cells based on the expression of the characteristic markers of stem (CD44 and CD133) and cancer stem cells (TROP-2, CD49f, and CD44). Our results revealed that the novel ACCA is a straightforward approach for determining the clonogenic capacity of cancer stem-like cells identified in both cell lines and patient samples.},

note = {Place: United States},

keywords = {*Cell Proliferation, AC133 Antigen, Antigens, Biomarkers, CD/metabolism, Cell Adhesion Molecules/metabolism, Cell Line, Cell Survival, Colonic Neoplasms/metabolism/*pathology, Flow Cytometry/*methods, Glycoproteins/metabolism, Humans, Hyaluronan Receptors/metabolism, In Vitro Techniques, Integrin alpha6/metabolism, Male, Neoplasm/metabolism, Neoplastic Stem Cells/metabolism/*pathology, Peptides/metabolism, Prostatic Neoplasms/metabolism/*pathology, Tumor, Tumor Stem Cell Assay/*methods, Tumor/metabolism},

pubstate = {published},

tppubtype = {article}

}

@article{vanhara_mutual_2013,

title = {Mutual cytokine crosstalk between colon cancer cells and microenvironment initiates development of distant metastases.},

author = {Petr Vaňhara and Karel Souček},

doi = {10.4161/jkst.23810},

issn = {2162-3988 2162-3996},

year  = {2013},

date = {2013-04-01},

journal = {JAK-STAT},

volume = {2},

number = {2},

pages = {e23810},

abstract = {Tumor growth and cancer development are considered clear examples of Darwinian selection, whereby random mutational events in heterogeneous cancer cell populations that best fit the selective microenvironment are preferred.(1) As a result, cancer cells evolve resistance to apoptosis, hide from immune surveillance and acquire the ability to invade other organs. Cancer cells, however, are not necessarily passive subjects of selection; they can actively subvert the host tissue to provide a favorable habitat for their growth. Recent findings by Calon et al. convincingly demonstrate that transforming growth factor-β-induced secretion of interleukin 11 by tumor stromal fibroblasts is a necessary prerequisite for the development of distant metastases in colorectal carcinoma. Thus, understanding the complex molecular feedback loops between cancer cells and the surrounding microenvironment (i.e., the tumor-associated stroma or invaded host tissue) should aid the identification of useful molecular targets for improving clinical management of advanced metastatic cancers.},

note = {Place: United States},

keywords = {dissemination, interleukin 11, Metastasis, metastatic niche, microenvironment, transforming growth factor-β, tumor stroma},

pubstate = {published},

tppubtype = {article}

}

@article{faust_ahr-mediated_2013,

title = {AhR-mediated changes in global gene expression in rat liver progenitor cells.},

author = {Dagmar Faust and Jan Vondráček and Pavel Krčmář and Lenka Smerdová and Jiřina Procházková and Eva Hrubá and Petra Hulinková and Bernd Kaina and Cornelia Dietrich and Miroslav Machala},

doi = {10.1007/s00204-012-0979-z},

issn = {1432-0738 0340-5761},

year  = {2013},

date = {2013-04-01},

journal = {Archives of toxicology},

volume = {87},

number = {4},

pages = {681–698},

abstract = {Although the tumor-promoting effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), coplanar polychlorinated biphenyls (PCBs), and related compounds in liver tissue are primarily attributed to the activation of the aryl hydrocarbon receptor (AhR), the underlying molecular mechanisms are still unclear. Liver progenitor (oval) cells have been suggested to constitute a potential target for hepatocarcinogenic chemicals. To better understand AhR-driven pathways, we analyzed the transcriptional program in response to coplanar PCB 126 in contact-inhibited rat liver progenitor WB-F344 cells using high-density microarrays. After 6-h treatment, we identified 145 significantly deregulated genes considered to be direct AhR-dependent target genes. The number of differentially regulated genes increased to 658 and 968 genes after 24 and 72 h, respectively. Gene ontology analysis revealed that these genes were primarily involved in drug and lipid metabolism, cell cycle and growth control, cancer developmental processes, cell-cell communication, and adhesion. Interestingly, the Wnt and TGF-β signaling pathways, both being involved in developmental and tumorigenic processes, belonged to the most affected pathways. AhR- and ARNT-dependent regulation of selected target genes of interest was then confirmed using TCDD as a model AhR agonist, together with pharmacological inhibition of the AhR and by RNA-interference techniques. We demonstrated AhR-dependent regulation of emerging and novel AhR target genes, such as Fst, Areg, Hbegf, Ctgf, Btg2, and Foxq1. Among them, the transcription factor Foxq1, recently suggested to contribute to tumor promotion and/or progression, was found to be regulated at both mRNA and protein levels by AhR/ARNT activation.},

note = {Place: Germany},

keywords = {Animals, Aryl Hydrocarbon/*genetics/metabolism, Cell Line, Epithelial Cells/drug effects/*metabolism/pathology, Estrogen Antagonists/toxicity, Gene Expression Regulation/drug effects/*genetics, Gene Knockdown Techniques, Liver/drug effects/*metabolism/pathology, Oligonucleotide Array Sequence Analysis, Polychlorinated Biphenyls/toxicity, Rats, Receptors, Stem Cells/drug effects/*metabolism/pathology},

pubstate = {published},

tppubtype = {article}

}

@article{andrysik_aryl_2013,

title = {Aryl hydrocarbon receptor-mediated disruption of contact inhibition is associated with connexin43 downregulation and inhibition of gap junctional intercellular communication.},

author = {Zdeněk Andrysík and Jiřina Procházková and Markéta Kabátková and Lenka Umannová and Pavlína Simečková and Jiří Kohoutek and Alois Kozubík and Miroslav Machala and Jan Vondráček},

doi = {10.1007/s00204-012-0963-7},

issn = {1432-0738 0340-5761},

year  = {2013},

date = {2013-03-01},

journal = {Archives of toxicology},

volume = {87},

number = {3},

pages = {491–503},

abstract = {The aryl hydrocarbon receptor (AhR) contributes to the control of cell-to-cell communication, cell adhesion, migration or proliferation. In the present study, we investigated the regulation of connexin43 (Cx43) and Cx43-mediated gap junctional intercellular communication (GJIC) during the AhR-dependent disruption of contact inhibition in non-tumorigenic liver epithelial cells. The contact inhibition of cell proliferation is a process restricting the cell division of confluent non-transformed cells, which is frequently abolished in cancer cells; however, the mechanisms contributing to its disruption are still only partially understood. Disruption of contact inhibition, which was induced by toxic AhR ligands 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) or polycyclic aromatic hydrocarbons in epithelial WB-F344 cells, reduced Cx43 protein levels, possibly via enhanced proteasomal degradation, significantly decreased the amount of gap junction plaques and downregulated GJIC, in an AhR-dependent manner. Although both intracellular and membrane Cx43 pools were markedly reduced in cells released from contact inhibition by TCDD, siRNA-mediated Cx43 knock-down was not sufficient to stimulate proliferation in contact-inhibited cells. Our data suggest that downregulation of Cx43/GJIC in non-transformed epithelial cells is an inherent part of disruption of contact inhibition, which occurs at the post-transcriptional level. This process runs in parallel with alterations of other forms of cell-to-cell communication, thus suggesting that toxic AhR agonists may simultaneously abrogate contact inhibition and reduce GJIC, two essential mechanisms linked to deregulation of cell-to-cell communication during tumor promotion and progression.},

note = {Place: Germany},

keywords = {Animals, Aryl Hydrocarbon/*agonists/genetics/metabolism, Benz(a)Anthracenes/toxicity, Carcinogens/*toxicity, Cell Communication/*drug effects, Cell Line, Cell Proliferation, Cell Transformation, Connexin 43/genetics/*metabolism, Contact Inhibition/*drug effects, Dose-Response Relationship, Down-Regulation, Drug, Epithelial Cells/*drug effects/metabolism/pathology, Fluorenes/toxicity, Gap Junctions/*drug effects/metabolism/pathology, Gene Knockdown Techniques, Indoles/pharmacology, Ligands, Liver Neoplasms/chemically induced/metabolism/pathology, Liver/*drug effects/metabolism/pathology, Neoplastic/chemically induced/metabolism/pathology, Phloroglucinol/analogs & derivatives/pharmacology, Phosphorylation, Polychlorinated Dibenzodioxins/toxicity, Proteasome Endopeptidase Complex/metabolism, Rats, Receptors, RNA Interference, Signal Transduction/*drug effects, Time Factors, Transfection},

pubstate = {published},

tppubtype = {article}

}

@article{kollar_prenylated_2013,

title = {Prenylated Flavonoids from Morus alba L. Cause Inhibition of G1/S Transition in THP-1 Human Leukemia Cells and Prevent the Lipopolysaccharide-Induced Inflammatory Response.},

author = {Peter Kollar and Tomáš Bárta and Jan Hošek and Karel Souček and Veronika Müller Závalová and Shushan Artinian and Rabih Talhouk and Karel Smejkal and Pavel Jr Suchý and Aleš Hampl},

doi = {10.1155/2013/350519},

issn = {1741-427X 1741-4288},

year  = {2013},

date = {2013-01-01},

journal = {Evidence-based complementary and alternative medicine : eCAM},

volume = {2013},

pages = {350519},

abstract = {Morus alba L. (MA) is a natural source of many compounds with different biological effects. It has been described to possess anti-inflammatory, antioxidant, and hepatoprotective activities. The aim of this study was to evaluate cytotoxicity of three flavonoids isolated from MA (kuwanon E, cudraflavone B, and 4'-O-methylkuwanon E) and to determine their effects on proliferation of THP-1 cells, and on cell cycle progression of cancer cells. Anti-inflammatory effects were also determined for all three given flavonoids. Methods used in the study included quantification of cells by hemocytometer and WST-1 assays, flow cytometry, western blotting, ELISA, and zymography. From the three compounds tested, cudraflavone B showed the strongest effects on cell cycle progression and viability of tumor and/or immortalized cells and also on inflammatory response of macrophage-like cells. Kuwanon E and 4'-O-methylkuwanon E exerted more sophisticated rather than direct toxic effect on used cell types. Our data indicate that mechanisms different from stress-related or apoptotic signaling pathways are involved in the action of these compounds. Although further studies are required to precisely define the mechanisms of MA flavonoid action in human cancer and macrophage-like cells, here we demonstrate their effects combining antiproliferative and anti-inflammatory activities, respectively.},

note = {Place: United States},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{starsichova_tgf-1_2012,

title = {TGF-β1 signaling plays a dominant role in the crosstalk between TGF-β1 and the aryl hydrocarbon receptor ligand in prostate epithelial cells.},

author = {Andrea Staršíchová and Eva Hrubá and Eva Slabáková and Zuzana Pernicová and Jiřina Procházková and Kateřina Pěnčíková and Václav Seda and Markéta Kabátková and Jan Vondráček and Alois Kozubík and Miroslav Machala and Karel Souček},

doi = {10.1016/j.cellsig.2012.04.008},

issn = {1873-3913 0898-6568},

year  = {2012},

date = {2012-08-01},

journal = {Cellular signalling},

volume = {24},

number = {8},

pages = {1665–1676},

abstract = {Crosstalk between the aryl hydrocarbon receptor (AhR) and transforming growth factor-β1 (TGF-β1) signaling has been observed in various experimental models. However, both molecular mechanism underlying this crosstalk and tissue-specific context of this interaction are still only partially understood. In a model of human non-tumorigenic prostate epithelial cells BPH-1, derived from the benign prostatic hyperplasia, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) persistently activates the AhR signaling pathway and induces expression of xenobiotic metabolizing enzymes, such as CYP1A1 or CYP1B1. Here we demonstrate that TGF-β1 suppresses the AhR-mediated gene expression through multiple mechanisms, involving inhibition of AhR expression and down-regulation of nuclear AhR, via a SMAD4-dependent pathway. In contrast, TCDD-induced AhR signaling does not affect either TGF-β1-regulated gene expression or epithelial-to-mesenchymal transition. These observations suggest that, in the context of prostate epithelium, TGF-β1 signaling plays a dominant role in the crosstalk with AhR signaling pathway. Given the importance of TGF-β1 signaling in regulation of prostate epithelial tissue homeostasis, as well as the recently revealed role of AhR in prostate development and tumorigenesis, the above findings contribute to our understanding of the mechanisms underlying the crosstalk between the two signaling pathways in the prostate-specific context.},

note = {Place: England},

keywords = {Aryl Hydrocarbon/antagonists & inhibitors/genetics/metabolism, Cells, Cultured, Epithelial Cells/*drug effects/*metabolism, Humans, Ligands, Male, Polychlorinated Dibenzodioxins/*pharmacology, Prostate/*cytology, Receptors, Recombinant Proteins/metabolism, Signal Transduction/*drug effects, Transforming Growth Factor beta1/genetics/*metabolism},

pubstate = {published},

tppubtype = {article}

}

@article{knopfova_c-myb_2012,

title = {c-Myb regulates matrix metalloproteinases 1/9, and cathepsin D: implications for matrix-dependent breast cancer cell invasion and metastasis.},

author = {Lucia Knopfová and Petr Beneš and Lucie Pekarčíková and Markéta Hermanová and Michal Masařík and Zuzana Pernicová and Karel Souček and Jan Smarda},

doi = {10.1186/1476-4598-11-15},

issn = {1476-4598},

year  = {2012},

date = {2012-03-01},

journal = {Molecular cancer},

volume = {11},

pages = {15},

abstract = {BACKGROUND: The c-Myb transcription factor is essential for the maintenance of stem-progenitor cells in bone marrow, colon epithelia, and neurogenic niches. c-Myb malfunction contributes to several types of malignancies including breast cancer. However, the function of c-Myb in the metastatic spread of breast tumors remains unexplored. In this study, we report a novel role of c-Myb in the control of specific proteases that regulate the matrix-dependent invasion of breast cancer cells. RESULTS: Ectopically expressed c-Myb enhanced migration and ability of human MDA-MB-231 and mouse 4T1 mammary cancer cells to invade Matrigel but not the collagen I matrix in vitro. c-Myb strongly increased the expression/activity of cathepsin D and matrix metalloproteinase (MMP) 9 and significantly downregulated MMP1. The gene coding for cathepsin D was suggested as the c-Myb-responsive gene and downstream effector of the migration-promoting function of c-Myb. Finally, we demonstrated that c-Myb delayed the growth of mammary tumors in BALB/c mice and affected the metastatic potential of breast cancer cells in an organ-specific manner. CONCLUSIONS: This study identified c-Myb as a matrix-dependent regulator of invasive behavior of breast cancer cells.},

note = {Place: England},

keywords = {Animals, Breast Neoplasms/genetics/*metabolism, Cathepsin D/genetics/*metabolism, Cell Line, Cell Movement/genetics/physiology, Electrophoresis, Female, Humans, Immunoblotting, Inbred BALB C, Matrix Metalloproteinase 1/genetics/*metabolism, Matrix Metalloproteinase 9/genetics/*metabolism, Mice, Neoplasm Metastasis/genetics/physiopathology, Polyacrylamide Gel, Proto-Oncogene Proteins c-myb/genetics/*metabolism, Real-Time Polymerase Chain Reaction, RNA, Small Interfering, Tumor},

pubstate = {published},

tppubtype = {article}

}

@article{valovicova_genotoxicity_2012,

title = {Genotoxicity of 7H-dibenzo[c,g]carbazole and its methyl derivatives in human keratinocytes.},

author = {Zuzana Valovičová and Monika Mesárošová and Lenka Trilecová and Eva Hrubá and Soňa Marvanová and Pavel Krčmář and Alena Milcová and Jana Schmuczerová and Jan Vondráček and Miroslav Machala and Jan Topinka and Alena Gábelová},

doi = {10.1016/j.mrgentox.2011.12.030},

issn = {0027-5107},

year  = {2012},

date = {2012-03-01},

journal = {Mutation research},

volume = {743},

number = {1-2},

pages = {91–98},

abstract = {Differences between tissues in the expression of drug-metabolizing enzymes may substantially contribute to tissue-specificity of chemical carcinogens. To verify this hypothesis, the spontaneously immortalized human keratinocytes HaCaT were used, in order to evaluate the genotoxic potential of 7H-dibenzo[c,g]carbazole (DBC), a known hepatocarcinogen and sarcomagen, and its synthetic tissue-specific derivatives, 5,9-dimethyl-DBC (DiMeDBC) and N-methyl-DBC (N-MeDBC), which manifest specific tropism to the liver and skin, respectively. HaCaT cells mainly express cytochrome P4501A1 (CYP1A1), which is involved in metabolism of DBC and N-MeDBC, but not DiMeDBC [10]. Both DBC and the sarcomagen N-MeDBC induced significant levels of DNA strand-breaks, micronuclei, and DNA adducts followed by the phosphorylation of the p53 protein and histone H2AX in HaCaT cells. In contrast, the specific hepatocarcinogen DiMeDBC was devoid of any significant genotoxic activity in this cell line. Our study demonstrates that the absence of drug-metabolizing enzyme(s) involved in DiMeDBC metabolism may contribute substantially to the tissue-specific genotoxicity of this hepatocarcinogen.},

note = {Place: Netherlands},

keywords = {Carbazoles/chemistry/*toxicity, Carcinogens/*toxicity, Cell Line, Cytochrome P-450 CYP1A1/metabolism, DNA Breaks, Humans, Keratinocytes/*drug effects/metabolism, Mutagenicity Tests, Mutagens/*toxicity, Organ Specificity, Single-Stranded},

pubstate = {published},

tppubtype = {article}

}

@article{torricelli_alternative_2012,

title = {Alternative Pathways of Cancer Cell Death by Rottlerin: Apoptosis versus Autophagy.},

author = {Claudia Torricelli and Sara Salvadori and Giuseppe Valacchi and Karel Souček and Eva Slabáková and Michela Muscettola and Nila Volpi and Emanuela Maioli},

doi = {10.1155/2012/980658},

issn = {1741-4288 1741-427X},

year  = {2012},

date = {2012-01-01},

journal = {Evidence-based complementary and alternative medicine : eCAM},

volume = {2012},

pages = {980658},

abstract = {Since the ability of cancer cells to evade apoptosis often limits the efficacy of radiotherapy and chemotherapy, autophagy is emerging as an alternative target to promote cell death. Therefore, we wondered whether Rottlerin, a natural polyphenolic compound with antiproliferative effects in several cell types, can induce cell death in MCF-7 breast cancer cells. The MCF-7 cell line is a good model of chemo/radio resistance, being both apoptosis and autophagy resistant, due to deletion of caspase 3 gene, high expression of the antiapoptotic protein Bcl-2, and low expression of the autophagic Beclin-1 protein. The contribution of autophagy and apoptosis to the cytotoxic effects of Rottlerin was examined by light, fluorescence, and electron microscopic examination and by western blotting analysis of apoptotic and autophagic markers. By comparing caspases-3-deficient (MCF-7(3def)) and caspases-3-transfected MCF-7 cells (MCF-7(3trans)), we found that Rottlerin induced a noncanonical, Bcl-2-, Beclin 1-, Akt-, and ERK-independent autophagic death in the former- and the caspases-mediated apoptosis in the latter, in not starved conditions and in the absence of any other treatment. These findings suggest that Rottlerin could be cytotoxic for different cancer cell types, both apoptosis competent and apoptosis resistant.},

note = {Place: United States},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{gabelova_genotoxicity_2011,

title = {Genotoxicity of 7H-dibenzo[c,g]carbazole and its tissue-specific derivatives in human hepatoma HepG2 cells is related to CYP1A1/1A2 expression.},

author = {Alena Gábelová and Zuzana Valovičová and Monika Mesárošová and Lenka Trilecová and Eva Hrubá and Soňa Marvanová and Pavel Krčmár and Alena Milcová and Jana Schmuczerová and Jan Vondráček and Miroslav Machala and Jan Topinka},

doi = {10.1002/em.20664},

issn = {1098-2280 0893-6692},

year  = {2011},

date = {2011-10-01},

journal = {Environmental and molecular mutagenesis},

volume = {52},

number = {8},

pages = {636–645},

abstract = {The goal of this study was to investigate the genotoxicity of 7H-dibenzo[c,g]carbazole (DBC), a ubiquitous environmental pollutant, and its methyl derivatives, 5,9-dimethylDBC (DiMeDBC), a strict hepatocarcinogen, and N-methylDBC (N-MeDBC), a specific sarcomagen in human hepatoma HepG2 cells, and to infer potential mechanisms underlying the biological activity of particular carcinogen. All dibenzocarbazoles, regardless the tissue specificity, induced significant DNA strand break levels and micronuclei in HepG2 cells; though a mitotic spindle dysfunction rather than a chromosome breakage was implicated in N-MeDBC-mediated micronucleus formation. While DBC and N-MeDBC produced stable DNA adducts followed with p53 protein phosphorylation at Ser-15, DiMeDBC failed. A significant increase in DNA strand breaks following incubation of exposed cells with a repair-specific endonuclease (Fpg protein) suggested that either oxidative DNA damage or unstable DNA-adducts might underlie DiMeDBC genotoxicity in human hepatoma cells. DiMeDBC and N-MeDBC increased substantially also the amount of CYP1A1/2 expression in HepG2 cells. Pretreatment of cells with substances affecting AhR-mediated CYP1A family of enzymes expression; however, diminished DiMeDBC and N-MeDBC genotoxicity. Our data clearly demonstrated differences in the mechanisms involved in the biological activity of DiMeDBC and N-MeDBC in human hepatoma cells; the genotoxicity of these DBC derivatives is closely related to CYP1A1/2 expression.},

note = {Place: United States},

keywords = {Base Sequence, Blotting, Carbazoles/*toxicity, Cell Survival/drug effects, Chromosome-Defective/chemically induced/statistics & numerical data, Comet assay, Cytochrome P-450 CYP1A1/*genetics, Cytochrome P-450 CYP1A2/*genetics, DNA adducts, DNA Breaks, Dose-Response Relationship, Drug, Hep G2 Cells, Histones/metabolism, Humans, Micronuclei, Micronucleus Tests, Mitotic Index, Molecular Sequence Data, Mutagens/*toxicity, Phosphorylation, Real-Time Polymerase Chain Reaction, Tumor Suppressor Protein p53/metabolism, Western},

pubstate = {published},

tppubtype = {article}

}

@article{hruba_gene_2011,

title = {Gene expression changes in human prostate carcinoma cells exposed to genotoxic and nongenotoxic aryl hydrocarbon receptor ligands.},

author = {Eva Hrubá and Jan Vondráček and Helena Líbalová and Jan Topinka and Vítězslav Bryja and Karel Souček and Miroslav Machala},

doi = {10.1016/j.toxlet.2011.07.011},

issn = {1879-3169 0378-4274},

year  = {2011},

date = {2011-10-01},

journal = {Toxicology letters},

volume = {206},

number = {2},

pages = {178–188},

abstract = {Carcinogenic polycyclic aromatic hydrocarbons (PAHs) are known as efficient mutagens and ligands of the aryl hydrocarbon receptor (AhR), which has been suggested to play an important role in prostate carcinogenesis. In order to evaluate the complex relationship between the genotoxicity and the AhR-mediated activity of PAHs in prostate cells, we selected benzo[a]pyrene (BaP) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), as model genotoxic and nongenotoxic AhR ligands, respectively, to explore global changes in gene expression in LNCaP cells by microarray analysis. We identified 112 genes that were differentially expressed in cells treated for 24h with BaP, TCDD or both compounds. Our data indicated that the impacts of BaP and TCDD on transcriptome of LNCaP cells significantly overlap, since over 64% of significantly up-regulated genes and 47% of down-regulated genes were similarly affected by both AhR ligands. This suggested that the activation of AhR played a prominent role in the nongenotoxic effects of BaP in the prostate carcinoma cell model LNCaP. Both AhR ligands suppressed expression of genes associated with cell cycle progression, DNA replication, spindle assembly checkpoint or DNA repair, which probably occurred secondary to inhibition of cell cycle progression. In contrast, we identified Wnt5a, an important regulator of prostate cancer progression, to be induced as early as 6h after exposure to both AhR ligands. The AhR ligand-induced Wnt5a upregulation, together with other observed alterations of gene expression, may further contribute to enhanced cell plasticity of prostate carcinoma cells.},

note = {Place: Netherlands},

keywords = {Aryl Hydrocarbon/*agonists, Benzo(a)pyrene/*toxicity, Carcinogens, Carcinoma/metabolism, Cell Cycle/drug effects, Cell Line, DNA Repair/drug effects, DNA Replication/drug effects, Environmental/*toxicity, Gene Expression Profiling, Gene Expression Regulation, Humans, Ligands, Male, Mutagens/*toxicity, Neoplastic/*drug effects, Oligonucleotide Array Sequence Analysis, Polychlorinated Dibenzodioxins/*toxicity, Prostatic Neoplasms/*metabolism, Proto-Oncogene Proteins/genetics/metabolism, Receptors, Spindle Apparatus/drug effects, Time Factors, Tumor, Wnt Proteins/genetics/metabolism, Wnt-5a Protein},

pubstate = {published},

tppubtype = {article}

}

@article{umannova_benzopyrene_2011,

title = {Benzo[a]pyrene and tumor necrosis factor-α coordinately increase genotoxic damage and the production of proinflammatory mediators in alveolar epithelial type II cells.},

author = {Lenka Umannová and Miroslav Machala and Jan Topinka and Jana Schmuczerová and Pavel Krčmář and Jiří Neča and Klára Šujanová and Alois Kozubík and Jan Vondráček},

doi = {10.1016/j.toxlet.2011.06.029},

issn = {1879-3169 0378-4274},

year  = {2011},

date = {2011-10-01},

journal = {Toxicology letters},

volume = {206},

number = {2},

pages = {121–129},

abstract = {Alveolar type II epithelial (AEII) cells regulate lung inflammatory response and, simultaneously, they are a target of environmental carcinogenic factors. We employed an in vitro model of rat AEII cells, the RLE-6TN cell line, in order to analyze the interactive effects of tumor necrosis factor-α (TNF-α), a cytokine which plays a key role in the initiation of inflammatory responses in the lung, and benzo[a]pyrene (BaP), a highly carcinogenic polycyclic aromatic hydrocarbon. TNF-α strongly augmented the formation of stable BaP diol epoxide-DNA adducts in AEII cells, which was associated with enhanced p53-Ser15 phosphorylation and decreased cell survival. The increased genotoxicity of BaP was associated with altered expression of cytochrome P450 (CYP) enzymes involved in its bioactivation, a simultaneous suppression of CYP1A1 and enhancement of CYP1B1 expression. Importantly, BaP and TNF-α acted synergistically to upregulate key inflammatory regulators in AEII cells, including the expression of inducible NO synthase and cyclooxygenase-2 (COX-2), and enhanced prostaglandin E2 production and expression of proinflammatory cytokines, such as TNF-α, interleukin-1β and interleukin-6. We observed that BaP and TNF-α together strongly activated p38 kinase, a principal regulator of inflammatory response. SB202190, a specific p38 inhibitor, prevented induction of both COX-2 and proinflammatory cytokines, thus confirming that p38 activity was crucial for the observed inflammatory reaction. Taken together, our data demonstrated, for the first time, that a proinflammatory cytokine and an environmental PAH may interact to potentiate both DNA damage and the inflammatory response in AEII cells, which may occur through coordinated upregulation of p38 activity.},

note = {Place: Netherlands},

keywords = {Alveolar Epithelial Cells/*drug effects/immunology/*metabolism, Animals, Apoptosis/drug effects, Aryl Hydrocarbon Hydroxylases/genetics/metabolism, Benzo(a)pyrene/metabolism/*toxicity, Carcinogens, Cell Line, Cell Proliferation/drug effects, Cytochrome P-450 CYP1A1/genetics/metabolism, Cytochrome P-450 CYP1B1, DNA Adducts/*metabolism, Environmental/toxicity, Enzyme Activation/drug effects, Gene Expression Regulation/drug effects, Inflammation Mediators/*metabolism, Messenger/metabolism, Mutagens/*toxicity, p38 Mitogen-Activated Protein Kinases/antagonists & inhibitors/metabolism, Phosphorylation/drug effects, Post-Translational/drug effects, Protein Kinase Inhibitors/pharmacology, Protein Processing, Rats, RNA, Tumor Necrosis Factor-alpha/*metabolism, Tumor Suppressor Protein p53/metabolism},

pubstate = {published},

tppubtype = {article}

}

@article{andrysik_activation_2011,

title = {Activation of the aryl hydrocarbon receptor is the major toxic mode of action of an organic extract of a reference urban dust particulate matter mixture: the role of polycyclic aromatic hydrocarbons.},

author = {Zdeněk Andrysík and Jan Vondráček and Soňa Marvanová and Miroslav Ciganek and Jiří Neča and Kateřina Pěnčíková and Brinda Mahadevan and Jan Topinka and William M. Baird and Alois Kozubík and Miroslav Machala},

doi = {10.1016/j.mrfmmm.2011.06.011},

issn = {0027-5107},

year  = {2011},

date = {2011-09-01},

journal = {Mutation research},

volume = {714},

number = {1-2},

pages = {53–62},

abstract = {Many of the toxic and carcinogenic effects of urban air pollution have been linked to polycyclic aromatic hydrocarbons (PAHs) adsorbed to airborne particulate matter (PM). The carcinogenic properties of PAHs in complex organic mixtures derived from PM have been chiefly attributed to their mutagenicity. Nevertheless, PAHs are also potent activators of the aryl hydrocarbon receptor (AhR), which may contribute to their nongenotoxic effects, including tumor promotion. As the genotoxicity of carcinogenic PAHs in complex mixtures derived from urban PM is often inhibited by other mixture constituents, the AhR-mediated activity of urban PM extracts might significantly contribute to the carcinogenic activity of such mixtures. In the present study, we used an organic extract of the urban dust standard reference material, SRM1649a, as a model mixture to study a range of toxic effects related to DNA damage and AhR activation. Both the organic extract and its neutral aromatic fraction formed a low number of DNA adducts per nucleotide in the liver epithelial WB-F344 cells model, without inducing DNA damage response, such as tumor suppressor p53 activation and apoptosis. In contrast, we found that this extract, as well as its neutral and polar fractions, were potent inducers of a range of AhR-mediated responses, including induction of the AhR-mediated transcription, such as cytochrome P450 1A1/1B1 expression, and the AhR-dependent cell proliferation. Importantly, these toxic events occurred at doses one order of magnitude lower than DNA damage. The AhR-mediated activity of the neutral fraction was linked to PAHs and their derivatives, as polychlorinated dibenzo-p-dioxins, dibenzofurans and biphenyls were only minor contributors to the overall AhR-mediated activity. Taken together, our data suggest that more attention should be paid to the AhR-dependent nongenotoxic events elicited by urban PM constituents, especially PAHs and their derivatives.},

note = {Place: Netherlands},

keywords = {Animals, Apoptosis/drug effects, Aryl Hydrocarbon/*metabolism, Cell Line, Cell Proliferation/drug effects, Cytochrome P-450 CYP1A1/metabolism, DNA Adducts/drug effects, DNA Damage/*drug effects, Dose-Response Relationship, Drug, Genes, Liver/drug effects, Mutagens/*toxicity, Organic Chemicals/*toxicity, p53/drug effects, Particulate Matter/*toxicity, Polycyclic Aromatic Hydrocarbons/*toxicity, Rats, Receptors},

pubstate = {published},

tppubtype = {article}

}

@article{slabakova_tgf-1-induced_2011,

title = {TGF-β1-induced EMT of non-transformed prostate hyperplasia cells is characterized by early induction of SNAI2/Slug.},

author = {Eva Slabáková and Zuzana Pernicová and Eva Slavíčková and Andrea Staršíchová and Alois Kozubík and Karel Souček},

doi = {10.1002/pros.21350},

issn = {1097-0045 0270-4137},

year  = {2011},

date = {2011-09-01},

journal = {The Prostate},

volume = {71},

number = {12},

pages = {1332–1343},

abstract = {BACKGROUND: Epithelial-mesenchymal transition (EMT) underlying cancer cell invasion and metastasis has been thoroughly studied in prostate cancer. Although EMT markers have been clinically observed in benign prostate hyperplasia, molecular events underlying the onset and progression of EMT in benign prostate cells have not been described. METHODS: EMT in BPH-1 cells was induced by TGF-β1 treatment and the kinetics of expression of EMT markers, regulators, and selected miRNAs was assessed by western blotting and quantitative RT-PCR. RESULTS: EMT in BPH-1 cells was accompanied by rapid up-regulation of SNAI2/Slug and ZEB1 transcription factors, while changes in expression levels of ZEB2 and miR-200 family members were observed after extended time intervals. Invasive phenotype with EMT hallmarks, characterizing tumorigenic clones derived from BPH-1 cells, was associated with increased mRNA levels of SNAI2, ZEB1, and ZEB2, but was not associated with significant changes in basal levels of miR-200 family members. RNA interference revealed that SNAI2/Slug is crucial for TGF-β1-induced vimentin up-regulation and migration of BPH-1 cells. CONCLUSIONS: This study suggests that in BPH-1 cells the transcription factor SNAI2/Slug is important for EMT initiation, while the ZEB family of transcription factors in cooperation with the miR-200 family may oppose the reversal of the EMT phenotype.},

note = {Place: United States},

keywords = {*Epithelial-Mesenchymal Transition/genetics, Biomarkers/metabolism, Cell Line, Cell Movement, Homeodomain Proteins/genetics, Humans, Kinetics, Male, Messenger/metabolism, MicroRNAs/metabolism, Neoplasm Invasiveness/genetics, Phenotype, Prostatic Hyperplasia/*physiopathology, Repressor Proteins/genetics, RNA, Snail Family Transcription Factors, Transcription Factors/*biosynthesis/genetics, Transforming Growth Factor beta1/*pharmacology, Up-Regulation/drug effects, Vimentin/metabolism, Zinc Finger E-box Binding Homeobox 2, Zinc Finger E-box-Binding Homeobox 1},

pubstate = {published},

tppubtype = {article}

}

@article{prochazkova_interplay_2011,

title = {The interplay of the aryl hydrocarbon receptor and β-catenin alters both AhR-dependent transcription and Wnt/β-catenin signaling in liver progenitors.},

author = {Jirina Procházková and Markéta Kabátková and Vítezslav Bryja and Lenka Umannová and Ondrej Bernatík and Alois Kozubík and Miroslav Machala and Jan Vondrácek},

doi = {10.1093/toxsci/kfr129},

issn = {1096-0929},

year  = {2011},

date = {2011-08-01},

journal = {Toxicological sciences : an official journal of the Society of Toxicology},

volume = {122},

number = {2},

pages = {349–360},

abstract = {β-catenin is a key integrator of cadherin-mediated cell-cell adhesion and transcriptional regulation through the Wnt/β-catenin pathway, which plays an important role in liver biology. Using a model of contact-inhibited liver progenitor cells, we examined the interactions of Wnt/β-catenin signaling with the aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor, which mediates the toxicity of dioxin-like compounds, including their effects on development and hepatocarcinogenesis. We found that AhR and Wnt/β-catenin cooperated in the induction of AhR transcriptional targets, such as Cyp1a1 and Cyp1b1. However, simultaneously, the activation of AhR led to a decrease of dephosphorylated active β-catenin pool, as well as to hypophosphorylation of Dishevelled, participating in regulation of Wnt signaling. A sustained AhR activation by its model ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), led to a downregulation of a number of Wnt/β-catenin pathway target genes. TCDD also induced a switch in cytokeratin expression, where downregulation of cytokeratins 14 and 19 was accompanied with an increased cytokeratin 8 expression. Together with a downregulation of additional markers associated with stem-like phenotype, this indicated that the AhR activation interfered with differentiation of liver progenitors. The downregulation of β-catenin was also related to a reduced cell adhesion, disruption of E-cadherin-mediated cell-cell junctions and an increased G1-S transition in liver progenitor cell line. In conclusion, although β-catenin augmented the expression of selected AhR target genes, the persistent AhR activation may lead to downregulation of Wnt/β-catenin signaling, thus altering differentiation and/or proliferative status of liver progenitor cells.},

note = {Place: United States},

keywords = {Animals, Aryl Hydrocarbon Hydroxylases/genetics/metabolism, Aryl Hydrocarbon/genetics/*metabolism, beta Catenin/genetics/*metabolism, Cadherins/genetics, Cell Adhesion, Cell Differentiation, Cell Line, Cytochrome P-450 CYP1A1/genetics/metabolism, Cytochrome P-450 CYP1B1, Down-Regulation/drug effects, Hepatocytes/drug effects, Inbred F344, Liver/*drug effects, Polychlorinated Dibenzodioxins/toxicity, Rats, Receptors, Wnt Proteins/genetics/*metabolism, Wnt Signaling Pathway},

pubstate = {published},

tppubtype = {article}

}

@article{pernicova_androgen_2011,

title = {Androgen depletion induces senescence in prostate cancer cells through down-regulation of Skp2.},

author = {Zuzana Pernicová and Eva Slabáková and Gvantsa Kharaishvili and Jan Bouchal and Milan Král and Zuzana Kunická and Miroslav Machala and Alois Kozubík and Karel Souček},

doi = {10.1593/neo.11182},

issn = {1476-5586 1522-8002},

year  = {2011},

date = {2011-06-01},

journal = {Neoplasia (New York, N.Y.)},

volume = {13},

number = {6},

pages = {526–536},

abstract = {Although the induction of senescence in cancer cells is a potent mechanism of tumor suppression, senescent cells remain metabolically active and may secrete a broad spectrum of factors that promote tumorigenicity in neighboring malignant cells. Here we show that androgen deprivation therapy (ADT), a widely used treatment for advanced prostate cancer, induces a senescence-associated secretory phenotype in prostate cancer epithelial cells, indicated by increases in senescence-associated β-galactosidase activity, heterochromatin protein 1β foci, and expression of cathepsin B and insulin-like growth factor binding protein 3. Interestingly, ADT also induced high levels of vimentin expression in prostate cancer cell lines in vitro and in human prostate tumors in vivo. The induction of the senescence-associated secretory phenotype by androgen depletion was mediated, at least in part, by down-regulation of S-phase kinase-associated protein 2, whereas the neuroendocrine differentiation of prostate cancer cells was under separate control. These data demonstrate a previously unrecognized link between inhibition of androgen receptor signaling, down-regulation of S-phase kinase-associated protein 2, and the appearance of secretory, tumor-promoting senescent cells in prostate tumors. We propose that ADT may contribute to the development of androgen-independent prostate cancer through modulation of the tissue microenvironment by senescent cells.},

note = {Place: United States},

keywords = {Androgen Antagonists/*pharmacology, Androgen/metabolism, beta-Galactosidase/metabolism, Blotting, Cathepsin B/metabolism, Cell Line, Cellular Senescence/*drug effects, Confocal, Down-Regulation/*drug effects, Flow Cytometry, Humans, Insulin-Like Growth Factor Binding Protein 3/metabolism, Male, Microscopy, Prostatic Neoplasms/genetics/metabolism/pathology, PTEN Phosphohydrolase/metabolism, Receptors, RNA Interference, S-Phase Kinase-Associated Proteins/genetics/*metabolism, Signal Transduction/drug effects, Tumor, Vimentin/metabolism, Western},

pubstate = {published},

tppubtype = {article}

}

@article{trilecova_toxic_2011,

title = {Toxic effects of methylated benzo[a]pyrenes in rat liver stem-like cells.},

author = {Lenka Trilecová and Simona Krčková and Soňa Marvanová and Kateřina Pĕnčíková and Pavel Krčmář and Jiří Neča and Petra Hulinková and Lenka Pálková and Miroslav Ciganek and Alena Milcová and Jan Topinka and Jan Vondráček and Miroslav Machala},

doi = {10.1021/tx200049x},

issn = {1520-5010 0893-228X},

year  = {2011},

date = {2011-06-01},

journal = {Chemical research in toxicology},

volume = {24},

number = {6},

pages = {866–876},

abstract = {The methylated benzo[a]pyrenes (MeBaPs) are present at significant levels in the environment, especially in the sediments contaminated by petrogenic PAHs. However, the existing data on their toxic effects in vitro and/or in vivo are still largely incomplete. Transcription factor AhR plays a key role in the metabolic activation of PAHs to genotoxic metabolites, but the AhR activation may also contribute to the tumor promoting effects of PAHs. In this study, the AhR-mediated activity of five selected MeBaP isomers was estimated in the DR-CALUX reporter gene assay performed in rat hepatoma cells. Detection of other effects, including induction of CYP1A1, CYP1B1, and AKR1C9 mRNAs, DNA adduct formation, production of reactive oxygen species, oxidation of deoxyguanosine, and cell cycle modulation and apoptosis, was performed in the rat liver epithelial WB-F344 cell line, a model of liver progenitor cells. We identified 1-MeBaP as the most potent inducer of AhR activation, stable DNA adduct formation, checkpoint kinase 1 and p53 phosphorylation, and apoptosis. These effects suggest that 1-MeBaP is a potent genotoxin eliciting a typical sequence of events ascribed to carcinogenic PAHs: induction of CYP1 enzymes, formation of high levels of DNA adducts, activation of DNA damage responses (including p53 phosphorylation), and cell death. In contrast, 10-MeBaP, representing BaP isomers substituted with the methyl group in the angular ring, elicited only low levels DNA adduct formation and apoptosis. Other MeBaPs under study also elicited strong apoptotic responses associated with DNA adduct formation as the prevalent mode of toxic action of these compounds in liver cells. MeBaPs induced a weak production of ROS, which did not lead to significant oxidative DNA damage. Importantly, 1-MeBaP and 3-MeBaP were found to be potent AhR agonists, one order of magnitude more potent than BaP, thus suggesting that the AhR-dependent modulations of gene expression, deregulation of cell survival mechanisms, and further nongenotoxic effects associated with AhR activation may further contribute to their tumor promotion and carcinogenicity.},

note = {Place: United States},

keywords = {Animals, Apoptosis/drug effects, Aryl Hydrocarbon/*metabolism, Benzo(a)pyrene/*chemistry/*toxicity, Cell Cycle/drug effects, Cell Line, Checkpoint Kinase 1, DNA Adducts/metabolism, Epithelial Cells/drug effects/metabolism, Gene Expression Regulation/drug effects, Liver/*cytology, Methylation, Mutagens/*chemistry/*toxicity, Oxidative Stress/drug effects, Protein Kinases/metabolism, Rats, Receptors, Stem Cells/drug effects/metabolism, Tumor, Tumor Suppressor Protein p53/metabolism},

pubstate = {published},

tppubtype = {article}

}

@article{hamers_vitro_2011,

title = {In vitro toxicity profiling of ultrapure non-dioxin-like polychlorinated biphenyl congeners and their relative toxic contribution to PCB mixtures in humans.},

author = {Timo Hamers and Jorke H. Kamstra and Peter H. Cenijn and Katerina Pencikova and Lenka Palkova and Pavlina Simeckova and Jan Vondracek and Patrik L. Andersson and Mia Stenberg and Miroslav Machala},

doi = {10.1093/toxsci/kfr043},

issn = {1096-0929},

year  = {2011},

date = {2011-05-01},

journal = {Toxicological sciences : an official journal of the Society of Toxicology},

volume = {121},

number = {1},

pages = {88–100},

abstract = {The toxic equivalency concept used for the risk assessment of polychlorinated biphenyls (PCBs) is based on the aryl hydrocarbon receptor (AhR)-mediated toxicity of coplanar dioxin-like (DL) PCBs. Most PCBs in the environment, however, are non-dioxin-like (NDL) PCBs that cannot adopt a coplanar structure required for AhR activation. For NDL-PCBs, no generally accepted risk concept is available because their toxicity is insufficiently characterized. Here, we systematically determined in vitro toxicity profiles for 24 PCBs regarding 10 different mechanisms of action. Prior to testing, NDL-PCB standards were purified to remove traces of DL compounds. All NDL-PCBs antagonized androgen receptor activation and inhibited gap junctional intercellular communication (GJIC). Lower chlorinated NDL-PCBs were weak estrogen receptor (ER) agonists, whereas higher chlorinated NDL-PCBs were weak ER antagonists. Several NDL-PCBs inhibited estradiol-sulfotransferase activity and bound to transthyretin (TTR) but with much weaker potencies than reported for hydroxylated PCB metabolites. AhR-mediated expression of uridine-glucuronyl transferase isozyme UGT1A6 was induced by DL-PCBs only. Hierarchical cluster analysis of the toxicity profiles yielded three separate clusters of NDL-PCBs and a fourth cluster of reference DL-PCBs. Due to small differences in relative potency among congeners, the highly abundant indicator PCBs 28, 52, 101, 118, 138, 153, and 180 also contributed most to the antiandrogenic, (anti)estrogenic, antithyroidal, tumor-promoting, and neurotoxic potencies calculated for PCB mixtures reported in human samples, whereas the most potent AhR-activating DL-PCB-126 contributed at maximum 0.2% to any of these calculated potencies. PCB-168 is recommended as an additional indicator congener, given its relatively high abundance and antiandrogenic, TTR-binding, and GJIC-inhibiting potencies.},

note = {Place: United States},

keywords = {Humans, In Vitro Techniques, Polychlorinated Biphenyls/administration & dosage/*toxicity},

pubstate = {published},

tppubtype = {article}

}

@article{benes_inhibition_2011,

title = {Inhibition of topoisomerase IIα: novel function of wedelolactone.},

author = {Petr Benes and Lucia Knopfova and Filip Trcka and Alice Nemajerova and Diana Pinheiro and Karel Soucek and Miroslav Fojta and Jan Smarda},

doi = {10.1016/j.canlet.2011.01.002},

issn = {1872-7980 0304-3835},

year  = {2011},

date = {2011-04-01},

journal = {Cancer letters},

volume = {303},

number = {1},

pages = {29–38},

abstract = {The naturally occurring coumestan wedelolactone has been previously shown to reduce growth of various cancer cells. So far, the growth-suppressing effect of wedelolactone has been attributed to the inhibition of the NFκB transcription factor and/or androgen receptors. We found that wedelolactone suppressed growth and induced apoptosis of androgen receptor-negative MDA-MB-231 breast cancer cells at concentrations that did not inhibit the NFκB activity. The cells responded to wedelolactone by the S and G2/M phase cell cycle arrest and induction of the DNA damage signaling. Wedelolactone interacted with dsDNA and inhibited the activity of DNA topoisomerase IIα. We conclude that wedelolactone can act as growth suppressor independently of NFκB and androgen receptors.},

note = {Place: Ireland},

keywords = {Antigens, Antineoplastic Agents/pharmacology, Apoptosis/drug effects, Breast Neoplasms/*drug therapy/enzymology/pathology, Cell Cycle/drug effects, Cell Growth Processes/drug effects, Cell Line, Cell Survival/drug effects, Coumarins/*pharmacology, DNA Damage, DNA Topoisomerases, DNA-Binding Proteins/*antagonists & inhibitors/metabolism, Enzyme-Linked Immunosorbent Assay, Female, Humans, Immunoblotting, Neoplasm/metabolism, Signal Transduction, Topoisomerase Inhibitors/*pharmacology, Tumor, Type II/metabolism},

pubstate = {published},

tppubtype = {article}

}

@article{lubcke-von_varel_polar_2011,

title = {Polar compounds dominate in vitro effects of sediment extracts.},

author = {Urte Lübcke-von Varel and Miroslav Machala and Miroslav Ciganek and Jiri Neca and Katerina Pencikova and Lenka Palkova and Jan Vondracek and Ivonne Löffler and Georg Streck and Georg Reifferscheid and Sini Flückiger-Isler and Jana M. Weiss and Marja Lamoree and Werner Brack},

doi = {10.1021/es103381y},

issn = {1520-5851 0013-936X},

year  = {2011},

date = {2011-03-01},

journal = {Environmental science & technology},

volume = {45},

number = {6},

pages = {2384–2390},

abstract = {Sediment extracts from three polluted sites of the river Elbe basin were fractionated using a novel online fractionation procedure. Resulting fractions were screened for mutagenic, aryl hydrocarbon receptor (AhR)-mediated, transthyretin (TTR)-binding, and estrogenic activities and their potency to inhibit gap junctional intercellular communication (GJIC) to compare toxicity patterns and identify priority fractions. Additionally, more than 200 compounds and compound classes were identified using GC-MS/MS, LC-MS/MS, and HPLC-DAD methods. For all investigated end points, major activities were found in polar fractions, which are defined here as fractions containing dominantly compounds with at least one polar functional group. Nonpolar PAH fractions contributed to mutagenic and AhR-mediated activities while inhibition of GJIC and estrogenic and TTR-binding activities were exclusively observed in the polar fractions. Known mutagens in polar fractions included nitro- and dinitro-PAHs, azaarenes, and keto-PAHs, while parent and monomethylated PAHs such as benzo[a]pyrene and benzofluoranthenes were identified in nonpolar fractions. Additionally, for one sample, high AhR-mediated activities were determined in one fraction characterized by PCDD/Fs, PCBs, and PCNs. Estrone, 17β-estradiol, 9H-benz[de]anthracen-7-one, and 4-nonylphenol were identified as possible estrogenic and TTR-binding compounds. Thus, not only nonpolar compounds such as PAHs, PCBs, and PCDD/Fs but also the less characterized and investigated more polar substances should be considered as potent mutagenic, estrogenic, AhR-inducing, TTR-binding, and GJIC-inhibiting components for future studies.},

note = {Place: United States},

keywords = {Animals, Aryl Hydrocarbon/analysis/chemistry, Biological Assay, Chemical Fractionation, Chemical/*analysis/chemistry/toxicity, Endocrine Disruptors/analysis/chemistry/toxicity, Environmental Monitoring, Geologic Sediments/*chemistry, Germany, Humans, Mutagens/analysis/chemistry/toxicity, Prealbumin/analysis/chemistry, Rats, Receptors, Toxicity Tests, Water Pollutants},

pubstate = {published},

tppubtype = {article}

}

@article{vondracek_interactions_2011,

title = {Interactions of the aryl hydrocarbon receptor with inflammatory mediators: beyond CYP1A regulation.},

author = {Jan Vondrácek and Lenka Umannová and Miroslav Machala},

doi = {10.2174/138920011795016827},

issn = {1875-5453 1389-2002},

year  = {2011},

date = {2011-02-01},

journal = {Current drug metabolism},

volume = {12},

number = {2},

pages = {89–103},

abstract = {The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor, which plays a major role in toxic effects of environmental pollutants. It is a pivotal regulator of several xenobiotic-metabolizing enzymes (XMEs), and is now considered to play an important role also in control of cell cycle, apoptosis and cell differentiation. The accumulating evidence suggests that there exists a multiple crosstalk between AhR activation and the signaling pathways activated by inflammatory mediators, such as nuclear factor-κB, a pleiotropic transcription factor controlling the immune/inflammatory responses. In this review, we summarize the current knowledge about the interactions of AhR with inflammatory mediators leading to deregulation of the AhR-dependent XMEs, as well as the evidence pointing to the role of AhR in modulation of inflammatory signals. These include altered expression of proinflammatory cytokines, such as tumor necrosis factor-alpha or interleukin-6, and deregulation of expression/activity of principle enzymes producing inflammatory mediators, such as cyclooxygenase-2. Recent studies also indicate that various classes of AhR ligands may differentially modulate AhR-dependent toxic responses and inflammation, which opens an interesting opportunity for a targeted synthesis of AhR ligands with anti-inflammatory properties. Although the role of activated AhR in the regulation of inflammation is still far from being completely understood, the close interactions between AhR and inflammatory signaling evidently can play a significant role in immune dysfunctions, metabolism of xenobiotics or carcinogenesis. The current review will focus mostly on the interaction of AhR and inflammation relative to mechanisms associated with the pathology of carcinogenesis.},

note = {Place: Netherlands},

keywords = {Animals, Anti-Inflammatory Agents/pharmacology, Aryl Hydrocarbon Hydroxylases/*genetics/metabolism/*physiology, Aryl Hydrocarbon/drug effects/*physiology, Enzymologic/*physiology, Gene Expression Regulation, Humans, Inflammation Mediators/metabolism/*physiology, Inflammation/drug therapy/metabolism/physiopathology, Receptors, Signal Transduction/*physiology, Xenobiotics/metabolism},

pubstate = {published},

tppubtype = {article}

}

@article{vondalova_blanarova_cisplatin_2011,

title = {Cisplatin and a potent platinum(IV) complex-mediated enhancement of TRAIL-induced cancer cells killing is associated with modulation of upstream events in the extrinsic apoptotic pathway.},

author = {Olga Vondálová Blanárová and Iva Jelínková and Arpád Szöor and Belma Skender and Karel Soucek and Viktor Horváth and Alena Vaculová and Ladislav Andera and Petr Sova and János Szöllosi and Jirina Hofmanová and György Vereb and Alois Kozubík},

doi = {10.1093/carcin/bgq220},

issn = {1460-2180 0143-3334},

year  = {2011},

date = {2011-01-01},

journal = {Carcinogenesis},

volume = {32},

number = {1},

pages = {42–51},

abstract = {TRAIL (tumor necrosis factor-related apoptosis-inducing ligand) can selectively trigger apoptosis in various cancer cell types. However, many cancer cells are resistant to death receptor-mediated apoptosis. Combination therapy with platinum complexes may affect TRAIL-induced signaling via modulation of various steps in apoptotic pathways. Here, we show that cisplatin or a more potent platinum(IV) complex LA-12 used in 20-fold lower concentration enhanced killing effects of TRAIL in human colon and prostate cancer cell lines via stimulation of caspase activity and overall apoptosis. Both platinum complexes increased DR5 surface expression in colon cancer cells. Small interfering RNA-mediated DR5 silencing rescued cells from sensitizing effects of platinum drugs on TRAIL-induced caspase-8 activation and apoptosis, showing the functional importance of DR5 in the effects observed. In addition, both cisplatin and LA-12 triggered the relocalization of DR4 and DR5 receptors to lipid rafts and accelerated internalization of TRAIL, which may also affect TRAIL signaling. Collectively, modulations of the initial steps of the extrinsic apoptotic pathway at the level of DR5 and plasma membrane are important for sensitization of colon and prostate cancer cells to TRAIL-induced apoptosis mediated by LA-12 and cisplatin.},

note = {Place: England},

keywords = {Amantadine/*analogs & derivatives/pharmacology, Apoptosis/*drug effects/physiology, Blotting, Cell Line, Cell Separation, Cisplatin/*pharmacology, Confocal, Flow Cytometry, Fluorescent Antibody Technique, Humans, Microscopy, Neoplasms/*metabolism, Organoplatinum Compounds/*pharmacology, Protein Transport/drug effects, Receptors, Reverse Transcriptase Polymerase Chain Reaction, RNA Interference, Signal Transduction/*drug effects/physiology, TNF-Related Apoptosis-Inducing Ligand/*metabolism, TNF-Related Apoptosis-Inducing Ligand/metabolism, Tumor, Western},

pubstate = {published},

tppubtype = {article}

}

@article{prochazkova_differential_2011,

title = {Differential effects of indirubin and 2,3,7,8-tetrachlorodibenzo-p-dioxin on the aryl hydrocarbon receptor (AhR) signalling in liver progenitor cells.},

author = {Jiřina Procházková and Alois Kozubík and Miroslav Machala and Jan Vondráček},

doi = {10.1016/j.tox.2010.10.003},

issn = {1879-3185 0300-483X},

year  = {2011},

date = {2011-01-01},

journal = {Toxicology},

volume = {279},

number = {1-3},

pages = {146–154},

abstract = {In the present study, we investigated the effects of potential endogenous ligand indirubin on the aryl hydrocarbon receptor (AhR) signalling, with a focus on the AhR-dependent gene expression and cell cycle progression in rat liver progenitor cells, and compared them with the effects of a model toxic AhR ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The low (picomolar and nanomolar) doses of indirubin, corresponding to expected endogenous levels, induced a transient translocation of AhR to the nucleus, while high (micromolar) doses induced a long-term AhR nuclear translocation, followed by its degradation, similar to the effects of TCDD. Whereas high doses of indirubin recruited AhR/ARNT1 dimer to rat Cyp1a1 promoter, the low doses did not induce its DNA binding, as revealed by the chromatin immunoprecipitation assay. This corresponded with the fact that the micromolar doses of indirubin significantly increased Cyp1a1/1b1 mRNA in a way similar to TCDD, while the low doses of indirubin were only poor inducers of Cyp1a1/1b1 expression. Comparable patterns of expression were observed also for other AhR gene targets, such as Nqo1 and Nrf2. Also, only micromolar doses of indirubin were able to mimic the effects of TCDD on cell cycle and proliferation of liver progenitor cells or hepatoma cells. Nevertheless, indirubin at low concentrations may have unique effects on gene expression in non-tumorigenic cells. Although both TCDD and the high doses of indirubin repressed plakoglobin (Jup) expression, the picomolar doses of indirubin, unlike the equimolar doses of TCDD, increased mRNA levels of this important desmosomal and adherens junctions constituent. These present data suggest that the outcome of AhR activation induced by indirubin at concentrations expected in vivo may differ from the AhR signalling triggered by exogenous toxic ligands, such as TCDD.},

note = {Place: Ireland},

keywords = {Animals, Aryl Hydrocarbon/*drug effects/metabolism, Carcinoma, Cell Cycle/drug effects, Cell Nucleus/metabolism, Cell Proliferation/drug effects, Cells, Chromatin Immunoprecipitation, Cultured, Dose-Response Relationship, Drug, Gene Expression Regulation/*drug effects, Hepatocellular/pathology, Indoles/administration & dosage/metabolism/pharmacology, Liver Neoplasms/pathology, Liver/cytology/drug effects/metabolism, Polychlorinated Dibenzodioxins/*toxicity, Protein Transport, Rats, Receptors, Signal Transduction/drug effects, Stem Cells/drug effects/metabolism},

pubstate = {published},

tppubtype = {article}

}

@article{soucek_growthdifferentiation_2010,

title = {Growth/differentiation factor-15 is an abundant cytokine in human seminal plasma.},

author = {Karel Soucek and Eva Slabáková and Petra Ovesná and Alice Malenovská and Alois Kozubík and Ales Hampl},

doi = {10.1093/humrep/deq264},

issn = {1460-2350 0268-1161},

year  = {2010},

date = {2010-12-01},

journal = {Human reproduction (Oxford, England)},

volume = {25},

number = {12},

pages = {2962–2971},

abstract = {BACKGROUND: Transforming growth factor-β cytokines have various biological effects in female reproductive tissue, including modulation of inflammatory response and induction of immune tolerance to seminal antigens in the reproductive tract. However, no studies have analyzed the presence of growth/differentiation factor-15 (GDF-15/macrophage inhibitory cytokine-1) in seminal fluid or demonstrated the quantity and form of GDF-15, its possible role or the relationship between its concentration and semen quality. METHODS: The form and the concentration of GDF-15 were determined in 53 seminal plasma samples of both fertile and infertile men by ELISA and western blot. The sperm cells of three volunteers were treated with recombinant GDF-15, and cell viability and apoptosis were assessed by flow cytometry. The effect of GDF-15 on vaginal epithelial cells and peripheral blood mononuclear cells (PBMCs) was analyzed by quantitative RT-PCR. RESULTS: The GDF-15 concentration in seminal plasma ranged from 0.2 to 6.6 μg/ml as determined by ELISA. Western blot analysis revealed that GDF-15 is present in the active form. In vitro cultivation of sperm cells with GDF-15 did not affect their viability or rates of apoptosis; however, it did inhibit proliferation of PBMCs and induce expression of FOXP3 in CD4+CD25+ cells. CONCLUSIONS: To the best of our knowledge, this is the first demonstration that GDF-15 is an abundant cytokine in seminal plasma, although its concentration is not associated with semen quality or the fertility/infertility status of the donors. Moreover, our data show that GDF-15 displays immunosuppressive characteristics.},

note = {Place: England},

keywords = {Adult, Apoptosis/drug effects, CD4-Positive T-Lymphocytes/metabolism, Cell Proliferation/drug effects, Cell Survival/drug effects, Epithelial Cells/metabolism, Female, Forkhead Transcription Factors/biosynthesis, Growth Differentiation Factor 15/*physiology, Humans, Interleukin-2 Receptor alpha Subunit/metabolism, Leukocytes, Male, Middle Aged, Mononuclear/drug effects, Semen Analysis, Semen/*metabolism, Spermatozoa},

pubstate = {published},

tppubtype = {article}

}

@article{starsichova_tgf-beta1_2010,

title = {TGF-beta1 suppresses IL-6-induced STAT3 activation through regulation of Jak2 expression in prostate epithelial cells.},

author = {Andrea Starsíchová and Eva Lincová and Zuzana Pernicová and Alois Kozubík and Karel Soucek},

doi = {10.1016/j.cellsig.2010.06.014},

issn = {1873-3913 0898-6568},

year  = {2010},

date = {2010-11-01},

journal = {Cellular signalling},

volume = {22},

number = {11},

pages = {1734–1744},

abstract = {Chronic inflammation plays an important role in the initiation and progression of various human diseases including benign prostatic hyperplasia or prostate cancer. Here we show that the proinflammatory cytokine interleukin-6 (IL-6) has prosurvival effects and chronically activates the Jak2/STAT3 signalling pathway in a model of benign prostatic hyperplasia (BPH-1). We demonstrate that the antiinflammatory cytokine transforming growth factor-beta1 (TGF-beta1), which also permanently activates its canonical signalling pathway through SMAD proteins in BPH-1 cells, modifies the effects of IL-6 on cell proliferation. Importantly, TGF-beta1 inhibits IL-6 signal transduction by decreasing the phosphorylation levels of STAT3. This effect is associated with decreased expression of Jak2 at both mRNA and protein levels. Moreover, we showed that TGF-beta1 inhibits IL-6-induced expression of the cancer-associated gene MUC1. These observations demonstrated a novel interaction between TGF-beta1 and IL-6 signalling and suggested another mechanism of how defects in TGF-beta signalling, frequently associated with prostate pathologies, can contribute to the disruption of tissue homeostasis.},

note = {Place: England},

keywords = {Cell Line, Cell Proliferation, Epithelial Cells/*metabolism, Humans, Interleukin-6/*antagonists & inhibitors/pharmacology, Janus Kinase 2/genetics/*metabolism, Male, Mucin-1/metabolism, Phosphorylation, Prostate/cytology/enzymology/*metabolism, Prostatic Hyperplasia/enzymology/*metabolism, RNA, RNA Interference, Signal Transduction, Smad Proteins/metabolism, Small Interfering/metabolism, STAT3 Transcription Factor/*metabolism, Transforming Growth Factor beta1/*pharmacology},

pubstate = {published},

tppubtype = {article}

}

@article{hruba_genotoxic_2010,

title = {Genotoxic polycyclic aromatic hydrocarbons fail to induce the p53-dependent DNA damage response, apoptosis or cell-cycle arrest in human prostate carcinoma LNCaP cells.},

author = {Eva Hrubá and Lenka Trilecová and Sona Marvanová and Pavel Krcmár and Lenka Vykopalová and Alena Milcová and Helena Líbalová and Jan Topinka and Andrea Starsíchová and Karel Soucek and Jan Vondrácek and Miroslav Machala},

doi = {10.1016/j.toxlet.2010.06.004},

issn = {1879-3169 0378-4274},

year  = {2010},

date = {2010-09-01},

journal = {Toxicology letters},

volume = {197},

number = {3},

pages = {227–235},

abstract = {Exposure to polycyclic aromatic hydrocarbons (PAHs) has been positively associated with prostate cancer, but knowledge of the formation of PAH-DNA adducts and related genotoxic events in prostatic cells is limited. In the present study, benzo[a]pyrene (BaP), a potent mutagenic PAH, formed significant levels of DNA adducts in cell lines derived from human prostate carcinoma. When analyzing the effect of BaP on the induction of CYP1 enzymes participating in the metabolic activation of PAHs in LNCaP cells, we found that BaP induced expression of CYP1A1 and CYP1A2, but not CYP1B1 enzyme. Despite a significant amount of DNA adducts being formed by BaP and, to a lesser extent also by another strong genotoxin, dibenzo[a,l]pyrene, neither apoptosis nor cell-cycle arrest were induced in LNCaP cells. LNCaP cells were not sensitized to the induction of apoptosis by PAHs even through inhibition of the phosphoinositide-3-kinase/Akt pro-survival pathway. The lack of apoptosis was not due a disruption of expression of pro-apoptotic and pro-survival members of the Bcl-2 family of apoptosis regulators. In contrast to other genotoxic stimuli, genotoxic PAHs failed to induce DNA double-strand breaks, as illustrated by the lack of phosphorylation of histone H2AX or checkpoint kinase-2. BaP did not activate p53, as evidenced by the lack of p53 accumulation, phosphorylation at Ser15, or induction of p53 transcriptional targets. Taken together, although genotoxic PAHs produced significant levels of DNA adducts in a model of human prostate carcinoma cells, they did not activate the mechanisms leading to elimination of cells with significant damage to DNA, presumably due to their failure to activate the p53-dependent DNA damage response.},

note = {Place: Netherlands},

keywords = {Animals, Apoptosis/*drug effects, Carcinoma/*metabolism, Cell Line, DNA Damage/*drug effects, Environmental Pollutants/toxicity, Gene Expression Regulation, Male, Neoplastic/drug effects, Polycyclic Aromatic Hydrocarbons/*toxicity, Prostatic Neoplasms/*metabolism, Tumor, Tumor Suppressor Protein p53/*metabolism},

pubstate = {published},

tppubtype = {article}

}

@article{svihalkova-sindlerova_-12_2010,

title = {LA-12 overcomes confluence-dependent resistance of HT-29 colon cancer cells to Pt (II) compounds.},

author = {Lenka Svihálková-Sindlerová and Vendula Foltinová and Alena Vaculová and Viktor Horváth and Karel Soucek and Petr Sova and Jirina Hofmanová and Alois Kozubík},

issn = {1791-7530 0250-7005},

year  = {2010},

date = {2010-04-01},

journal = {Anticancer research},

volume = {30},

number = {4},

pages = {1183–1188},

abstract = {BACKGROUND: LA-12 is a new platinum (IV) drug with promising cytotoxic effects in a wide range of cancer cell lines. Its confluence-dependent effects were compared with cisplatin (CDDP) and oxaliplatin (L-OHP) in HT-29 cells. MATERIALS AND METHODS: Cytotoxicity was determined by MTT test, eosin exclusion assay, and cell number quantification. The cell cycle was analysed using propidium iodide DNA staining (flow cytometry), apoptosis by phosphatidylserine externalisation (annexin-V assay), mitochondrial membrane potential by flow cytometry, nuclear morphology by means of fluorescence microscopy, and PARP cleavage by Western blotting. RESULTS: While L-OHP and CDDP were practically inactive in the subconfluent cell population, LA-12 showed a similar toxicity in both subconfluent and growing populations. All compounds induced apoptosis, although with different potentials. CONCLUSION: LA-12 was able to overcome confluence-dependent resistance of HT-29 cells observed for other platinum compounds, which may have potential therapeutic use in slowly growing tumours.},

note = {Place: Greece},

keywords = {Adenocarcinoma/*drug therapy, Amantadine/*analogs & derivatives/pharmacology, Antineoplastic Agents/*pharmacology, Apoptosis/drug effects, Cell Adhesion/drug effects, Cisplatin/pharmacology, Colonic Neoplasms/*drug therapy/pathology, Dose-Response Relationship, Drug, Drug resistance, HT29 Cells, Humans, Neoplasm, Organoplatinum Compounds/*pharmacology, Oxaliplatin},

pubstate = {published},

tppubtype = {article}

}