Latest Publications

@article{nemec_discovery_2024,

title = {Discovery of Two Highly Selective Structurally Orthogonal Chemical Probes for Activin Receptor-like Kinases 1 and 2.},

author = {Václav Němec and Marek Remeš and Petr Beňovský and Michael C. Böck and Eliška Šranková and Jong Fu Wong and Julien Cros and Eleanor Williams and Lap Hang Tse and David Smil and Deeba Ensan and Methvin B. Isaac and Rima Al-Awar and Regina Gomolková and Vlad-Constantin Ursachi and Bohumil Fafílek and Zuzana Kahounová and Ráchel Víchová and Ondřej Vacek and Benedict-Tilman Berger and Carrow I. Wells and Cesear R. Corona and James D. Vasta and Matthew B. Robers and Pavel Krejci and Karel Souček and Alex N. Bullock and Stefan Knapp and Kamil Paruch},

doi = {10.1021/acs.jmedchem.4c00629},

issn = {1520-4804 0022-2623},

year  = {2024},

date = {2024-08-01},

journal = {Journal of medicinal chemistry},

volume = {67},

number = {15},

pages = {12632–12659},

abstract = {Activin receptor-like kinases 1-7 (ALK1-7) regulate a complex network of SMAD-independent as well as SMAD-dependent signaling pathways. One of the widely used inhibitors for functional investigations of these processes, in particular for bone morphogenetic protein (BMP) signaling, is LDN-193189. However, LDN-193189 has insufficient kinome-wide selectivity complicating its use in cellular target validation assays. Herein, we report the identification and comprehensive characterization of two chemically distinct highly selective inhibitors of ALK1 and ALK2, M4K2234 and MU1700, along with their negative controls. We show that both MU1700 and M4K2234 efficiently block the BMP pathway via selective in cellulo inhibition of ALK1/2 kinases and exhibit favorable in vivo profiles in mice. MU1700 is highly brain penetrant and shows remarkably high accumulation in the brain. These high-quality orthogonal chemical probes offer the selectivity required to become widely used tools for in vitro and in vivo investigation of BMP signaling.},

note = {Place: United States},

keywords = {*Activin Receptors, Activin Receptors, Animals, Bone Morphogenetic Proteins/metabolism, Drug Discovery, Humans, Mice, Molecular Probes/chemistry, Protein Kinase Inhibitors/pharmacology/chemistry, Pyrazoles/chemistry/pharmacology/chemical synthesis, Signal Transduction/drug effects, Structure-Activity Relationship, Type I/antagonists & inhibitors/metabolism, Type II/metabolism/antagonists & inhibitors},

pubstate = {published},

tppubtype = {article}

}

@article{prochazkova_adaptive_2018,

title = {Adaptive changes in global gene expression profile of lung carcinoma A549 cells acutely exposed to distinct types of AhR ligands.},

author = {Jiřina Procházková and Simona Strapáčová and Lucie Svržková and Zdeněk Andrysík and Martina Hýžďalová and Eva Hrubá and Kateřina Pěnčíková and Helena Líbalová and Jan Topinka and Jiří Kléma and Joaquín M. Espinosa and Jan Vondráček and Miroslav Machala},

doi = {10.1016/j.toxlet.2018.04.024},

issn = {1879-3169 0378-4274},

year  = {2018},

date = {2018-08-01},

journal = {Toxicology letters},

volume = {292},

pages = {162–174},

abstract = {Exposure to persistent ligands of aryl hydrocarbon receptor (AhR) has been found to cause lung cancer in experimental animals, and lung adenocarcinomas are often associated with enhanced AhR expression and aberrant AhR activation. In order to better understand the action of toxic AhR ligands in lung epithelial cells, we performed global gene expression profiling and analyze TCDD-induced changes in A549 transcriptome, both sensitive and non-sensitive to CH223191 co-treatment. Comparison of our data with results from previously reported microarray and ChIP-seq experiments enabled us to identify candidate genes, which expression status reflects exposure of lung cancer cells to TCDD, and to predict processes, pathways (e.g. ER stress, Wnt/β-cat, IFNɣ, EGFR/Erbb1), putative TFs (e.g. STAT, AP1, E2F1, TCF4), which may be implicated in adaptive response of lung cells to TCDD-induced AhR activation. Importantly, TCDD-like expression fingerprint of selected genes was observed also in A549 cells exposed acutely to both toxic (benzo[a]pyrene, benzo[k]fluoranthene) and endogenous AhR ligands (2-(1H-Indol-3-ylcarbonyl)-4-thiazolecarboxylic acid methyl ester and 6-formylindolo[3,2-b]carbazole). Overall, our results suggest novel cellular candidates, which could help to improve monitoring of AhR-dependent transcriptional activity during acute exposure of lung cells to distinct types of environmental pollutants.},

note = {Place: Netherlands},

keywords = {A549 Cells, Aryl hydrocarbon receptor, Aryl Hydrocarbon/*agonists/metabolism, Azo Compounds/toxicity, Basic Helix-Loop-Helix Transcription Factors/*agonists/metabolism, Benzo(a)pyrene/toxicity, Carbazoles/toxicity, Dioxins, Environmental Pollutants/*toxicity, Fluorenes/toxicity, Gene Expression Profiling/methods, Gene Expression Regulation, Gene Regulatory Networks/drug effects, Genetic/drug effects, Global gene expression profiling, Humans, Indoles/toxicity, Ligands, Lung cancer, Lung Neoplasms/*genetics/metabolism, Neoplastic/*drug effects, Oligonucleotide Array Sequence Analysis, Polychlorinated Dibenzodioxins/toxicity, Pyrazoles/toxicity, Receptors, Signal Transduction/drug effects, Thiazoles/toxicity, Time Factors, Transcription, Transcriptional Activation/drug effects, Transcriptome/*drug effects},

pubstate = {published},

tppubtype = {article}

}

@article{pencikova_vitro_2018,

title = {In vitro profiling of toxic effects of prominent environmental lower-chlorinated PCB congeners linked with endocrine disruption and tumor promotion.},

author = {Kateřina Pěnčíková and Lucie Svržková and Simona Strapáčová and Jiří Neča and Iveta Bartoňková and Zdeněk Dvořák and Martina Hýžďalová and Jakub Pivnička and Lenka Pálková and Hans-Joachim Lehmler and Xueshu Li and Jan Vondráček and Miroslav Machala},

doi = {10.1016/j.envpol.2018.02.067},

issn = {1873-6424 0269-7491},

year  = {2018},

date = {2018-06-01},

journal = {Environmental pollution (Barking, Essex : 1987)},

volume = {237},

pages = {473–486},

abstract = {The mechanisms contributing to toxic effects of airborne lower-chlorinated PCB congeners (LC-PCBs) remain poorly characterized. We evaluated in vitro toxicities of environmental LC-PCBs found in both indoor and outdoor air (PCB 4, 8, 11, 18, 28 and 31), and selected hydroxylated metabolites of PCB 8, 11 and 18, using reporter gene assays, as well as other functional cellular bioassays. We focused on processes linked with endocrine disruption, tumor promotion and/or regulation of transcription factors controlling metabolism of both endogenous compounds and xenobiotics. The tested LC-PCBs were found to be mostly efficient anti-androgenic (within nanomolar - micromolar range) and estrogenic (at micromolar concentrations) compounds, as well as inhibitors of gap junctional intercellular communication (GJIC) at micromolar concentrations. PCB 8, 28 and 31 were found to partially inhibit the aryl hydrocarbon receptor (AhR)-mediated activity. The tested LC-PCBs were also partial constitutive androstane receptor (CAR) and pregnane X receptor (PXR) agonists, with PCB 4, 8 and 18 being the most active compounds. They were inactive towards other nuclear receptors, such as vitamin D receptor, thyroid receptor α, glucocorticoid receptor or peroxisome proliferator-activated receptor γ. We found that only PCB 8 contributed to generation of oxidative stress, while all tested LC-PCBs induced arachidonic acid release (albeit without further modulations of arachidonic acid metabolism) in human lung epithelial cells. Importantly, estrogenic effects of hydroxylated (OH-PCB) metabolites of LC-PCBs (4-OH-PCB 8, 4-OH-PCB 11 and 4'-OH-PCB 18) were higher than those of the parent PCBs, while their other toxic effects were only slightly altered or suppressed. This suggested that metabolism may alter toxicity profiles of LC-PCBs in a receptor-specific manner. In summary, anti-androgenic and estrogenic activities, acute inhibition of GJIC and suppression of the AhR-mediated activity were found to be the most relevant modes of action of airborne LC-PCBs, although they partially affected also additional cellular targets.},

note = {Place: England},

keywords = {Air Pollutants/*toxicity, Airborne polychlorinated biphenyls, Cell Line, Constitutive Androstane Receptor, Cytoplasmic and Nuclear/metabolism, Endocrine disruption, Endocrine Disruptors/metabolism/*toxicity, Epithelial Cells/drug effects, Humans, HydroxyLated PCBs, Hydroxylation, Metabolism of xenobiotics, Neoplasms/metabolism, Polychlorinated Biphenyls/metabolism/*toxicity, Pregnane X receptor, Receptors, Signal Transduction/drug effects, Steroid/metabolism, Tumor promotion},

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{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{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{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{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{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{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{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{takacova_role_2009,

title = {Role of aryl hydrocarbon receptor in modulation of the expression of the hypoxia marker carbonic anhydrase IX.},

author = {Martina Takacova and Tereza Holotnakova and Jan Vondracek and Miroslav Machala and Katerina Pencikova and Katarina Gradin and Lorenz Poellinger and Jaromir Pastorek and Silvia Pastorekova and Juraj Kopacek},

doi = {10.1042/BJ20080952},

issn = {1470-8728 0264-6021},

year  = {2009},

date = {2009-04-01},

journal = {The Biochemical journal},

volume = {419},

number = {2},

pages = {419–425},

abstract = {Tumour-associated expression of CA IX (carbonic anhydrase IX) is to a major extent regulated by HIF-1 (hypoxia-inducible factor-1) which is important for transcriptional activation and consists of the oxygen-regulated subunit HIF-1alpha and the partner factor ARNT [AhR (aryl hydrocarbon receptor) nuclear translocator]. We have previously observed that HIF-1alpha competes with the AhR for interaction with ARNT under conditions when both conditionally regulated factors are activated. We have therefore investigated whether TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin)-induced activation of the AhR pathway might interfere with CA IX expression. The results from the present study suggest that TCDD treatment reduces hypoxic induction of both CA IX mRNA and protein expression. Moreover, the transcriptional activity of the CA9 promoter was significantly reduced by expression of CAAhR (constitutively active AhR), which activates transcription in a ligand-independent manner. Finally, we found that ARNT is critical for both hypoxic induction and the TCDD-mediated inhibition of CA9 expression.},

note = {Place: England},

keywords = {alpha Subunit, Animals, Antigens, Aryl Hydrocarbon/genetics/metabolism/*physiology, Binding Sites, Blotting, Carbonic Anhydrase IX, Carbonic Anhydrases/genetics/*metabolism, Cell Hypoxia/genetics/*physiology, Cell Line, Chromatin Immunoprecipitation, Genetic/genetics, Humans, Hypoxia-Inducible Factor 1, Mice, Neoplasm/genetics, Polychlorinated Dibenzodioxins/pharmacology, Polymerase Chain Reaction, Promoter Regions, Protein Binding/drug effects, Receptors, Reverse Transcriptase Polymerase Chain Reaction, Signal Transduction/drug effects, Tumor, Western},

pubstate = {published},

tppubtype = {article}

}

@article{ondrouskova_heavy_2009,

title = {Heavy metals induce phosphorylation of the Bcl-2 protein by Jun N-terminal kinase.},

author = {Eva Ondrousková and Jana Slovácková and Vendula Pelková and Jirina Procházková and Karel Soucek and Petr Benes and Jan Smarda},

doi = {10.1515/BC.2009.007},

issn = {1431-6730},

year  = {2009},

date = {2009-01-01},

journal = {Biological chemistry},

volume = {390},

number = {1},

pages = {49–58},

abstract = {The Bcl-2 protein is one of the key components of biochemical pathways controlling programmed cell death. The function of this protein can be regulated by posttranslational modifications. Phosphorylation of Bcl-2 has been considered to be significantly associated with cell cycle arrest in the G2/M phase of the cell cycle, and with cell death caused by defects of microtubule dynamics. This study shows that phosphorylation of Bcl-2 can be induced by heavy metals due to activation of the Jun N-terminal kinase pathway that is not linked to the G2/M cell cycle arrest. Furthermore, we demonstrate that hyperphosphorylated Bcl-2 protein is a more potent inhibitor of zinc-induced cell death than its hypophosphorylated mutant form. These data suggest that regulation of Bcl-2 protein function by phosphorylation is an important part of cell responses to stress.},

note = {Place: Germany},

keywords = {Animals, Apoptosis/drug effects, Cell Line, Electrophoresis, Gene Expression Regulation, Heavy/*pharmacology, Humans, JNK Mitogen-Activated Protein Kinases/*metabolism, Metals, Neoplastic/drug effects, Phosphorylation/drug effects, Physiological/drug effects, Post-Translational/drug effects, Protein Processing, Proto-Oncogene Proteins c-bcl-2/*metabolism, Signal Transduction/drug effects, Stress, Tumor, Zinc/pharmacology},

pubstate = {published},

tppubtype = {article}

}