Latest Publications

@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{prochazkova_monocytic_2009,

title = {Monocytic differentiation of leukemic HL-60 cells induced by co-treatment with TNF-alpha and MK886 requires activation of pro-apoptotic machinery.},

author = {Jirina Procházková and Lenka Stixová and Karel Soucek and Jirina Hofmanová and Alois Kozubík},

doi = {10.1111/j.1600-0609.2009.01240.x},

issn = {1600-0609 0902-4441},

year  = {2009},

date = {2009-07-01},

journal = {European journal of haematology},

volume = {83},

number = {1},

pages = {35–47},

abstract = {The block of hematopoietic differentiation program in acute myeloid leukemia cells can be overcome by differentiating agent like retinoic acid, but it has several side effects. A study of other differentiation signaling pathways is therefore useful to predict potential targets of anti-leukemic therapy. We demonstrated previously that the co-treatment of HL-60 cells with Tumor necrosis factor-alpha (TNF-alpha) (1 ng/mL) and inhibitor of 5-lipoxygenase MK886 (5 microm) potentiated both monocytic differentiation and apoptosis. In this study, we detected enhanced activation of three main types of mitogen-activated protein kinases (MAPKs) (p38, c-Jun amino-terminal kinase [JNK], extracellular signal-regulated kinase [ERK]), so we assessed their role in differentiation using appropriate pharmacologic inhibitors. The inhibition of pro-apoptotic MAPKs (p38 and JNK) suppressed the effect of MK886 + TNF-alpha co-treatment. On the other hand, down-regulation of pro-survival ERK pathway led to increased differentiation. Those effects were accompanied by increased activation of caspases in cells treated by MK886 + TNF-alpha. Pan-caspase inhibitor ZVAD-fmk significantly decreased both number of apoptotic and differentiated cells. The same effect was observed after inhibition of caspase 9, but not caspase 3 and 8. To conclude, we evidenced that the activation of apoptotic processes and pathways supporting apoptosis (p38 and JNK MAPKs) is required for the monocytic differentiation of HL-60 cells.},

note = {Place: England},

keywords = {Acute/*drug therapy/metabolism/*pathology, Amino Acid Chloromethyl Ketones/pharmacology, Apoptosis/*drug effects/physiology, Caspase Inhibitors, Caspases/metabolism, Cell Differentiation/drug effects, Cysteine Proteinase Inhibitors/pharmacology, Enzyme Activation/drug effects, HL-60 Cells, Humans, Indoles/*pharmacology, Leukemia, Lipoxygenase Inhibitors/pharmacology, MAP Kinase Signaling System/drug effects, Monocytes/*drug effects/pathology, NF-kappa B/antagonists & inhibitors, Promyelocytic, Tumor Necrosis Factor-alpha/*pharmacology},

pubstate = {published},

tppubtype = {article}

}

@article{vaculova_different_2006,

title = {Different modulation of TRAIL-induced apoptosis by inhibition of pro-survival pathways in TRAIL-sensitive and TRAIL-resistant colon cancer cells.},

author = {Alena Vaculová and Jirina Hofmanová and Karel Soucek and Alois Kozubík},

doi = {10.1016/j.febslet.2006.11.004},

issn = {0014-5793},

year  = {2006},

date = {2006-12-01},

journal = {FEBS letters},

volume = {580},

number = {28-29},

pages = {6565–6569},

abstract = {Epithelial cells can be manipulated to undergo apoptosis depending on the balance between pro-survival and apoptotic signals. We showed that TRAIL-induced apoptosis may be differentially regulated by inhibitors of MEK ERK (U0126) or PI3K/Akt (LY294002) pathway in TRAIL-sensitive (HT-29) and TRAIL-resistant (SW620) human epithelial colon cancer cells. U0126 or LY294002 significantly enhanced TRAIL-induced apoptosis in HT-29 cells, but not in SW620 cells. We report a different regulation of the level of an anti-apoptotic Mcl-1 protein under MEK/ERK or PI3K/Akt pathway inhibition and suggest the mechanisms involved. A special attention was paid to the role of the ERK1/2, Akt, and glycogen synthase kinase 3beta.},

note = {Place: England},

keywords = {Apoptosis/*drug effects, Caspase 8/metabolism, Cell Survival/drug effects, Colonic Neoplasms/*pathology, Enzyme Activation/drug effects, Enzyme Inhibitors/pharmacology, Extracellular Signal-Regulated MAP Kinases/antagonists & inhibitors, Glycogen Synthase Kinase 3 beta, Glycogen Synthase Kinase 3/metabolism, HT29 Cells, Humans, Keratin-18/metabolism, Mitogen-Activated Protein Kinase 1/antagonists & inhibitors, Mitogen-Activated Protein Kinase 3/antagonists & inhibitors, Mitogen-Activated Protein Kinase Kinases/antagonists & inhibitors, Myeloid Cell Leukemia Sequence 1 Protein, Neoplasm Proteins/metabolism, Phosphoinositide-3 Kinase Inhibitors, Phosphorylation/drug effects, Poly(ADP-ribose) Polymerases/metabolism, Proto-Oncogene Proteins c-akt/antagonists & inhibitors, Proto-Oncogene Proteins c-bcl-2/metabolism, TNF-Related Apoptosis-Inducing Ligand/*pharmacology},

pubstate = {published},

tppubtype = {article}

}

@article{soucek_transforming_2006,

title = {Transforming growth factor-beta1 inhibits all-trans retinoic acid-induced apoptosis.},

author = {Karel Soucek and Jirí Pacherník and Lukás Kubala and Jan Vondrácek and Jirina Hofmanová and Alois Kozubík},

doi = {10.1016/j.leukres.2005.09.007},

issn = {0145-2126},

year  = {2006},

date = {2006-05-01},

journal = {Leukemia research},

volume = {30},

number = {5},

pages = {607–623},

abstract = {The interaction between retinoids and transforming growth factor-beta1 (TGF-beta1) leading to regulation of proliferation, differentiation and apoptosis is not still fully understood. In this study, we demonstrated that a combination treatment with all-trans retinoic acid (ATRA) and TGF-beta1 led to the enhancement of ATRA-induced suppression of cell proliferation, which is accompanied by inhibition of ATRA-induced apoptosis in human leukemia HL-60 cells. This effect was preceded by the arrest of cells in G0/G1 cell cycle phase linked with pRb protein dephosphorylation, continuous accumulation of p21 and transiently increased level of p27, inhibitors of cyclin-dependent kinases. Inhibition of ATRA-induced apoptosis by TGF-beta1 was associated with an increased level of Mcl-1 protein, an anti-apoptotic member of Bcl-2 family, but not with inhibition of mitochondrial membrane depolarization. Levels of other Bcl-2 family proteins (Bcl-2, Bcl-X(L), Bad, Bak, Bax) were unaffected by simultaneous ATRA and TGF-beta1 treatment, when compared to ATRA alone. Upregulation of c-FLIP(L) protein, an inhibitor of apoptosis induced by tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), correspond with inhibition of ATRA-induced (autocrine TRAIL-mediated) caspase-8 activation and apoptosis. These results suggest that apoptosis inhibition associated with proliferation block could depend on modulation of the TRAIL apoptotic pathway and regulation of the Mcl-1 protein level. In summary, we demonstrate that the balance of processes leading to regulation of proliferation and differentiation of myeloid cells can modulate cell sensitivity to apoptosis-inducing stimuli.},

note = {Place: England},

keywords = {Apoptosis Regulatory Proteins/metabolism/pharmacology, Apoptosis/*drug effects/physiology, bcl-2-Associated X Protein/drug effects/metabolism, CASP8 and FADD-Like Apoptosis Regulating Protein, Caspase 3, Caspase 8, Caspases/drug effects/metabolism, CD11b Antigen/biosynthesis/drug effects, Cell Cycle/drug effects, Cell Differentiation/drug effects, Cell Proliferation/drug effects, Cell Survival/drug effects, Cultured, Cyclin-Dependent Kinase Inhibitor p21/biosynthesis/drug effects, Drug Synergism, Enzyme Activation/drug effects, G1 Phase/drug effects, Granulocytes/drug effects/physiology, HL-60 Cells, Humans, Intracellular Signaling Peptides and Proteins/drug effects/metabolism, Membrane Glycoproteins/metabolism/pharmacology, Mitochondrial Membranes/drug effects/physiology, Myeloid Cell Leukemia Sequence 1 Protein, Neoplasm Proteins/drug effects/metabolism, Phosphorylation, Proto-Oncogene Proteins c-bcl-2/drug effects/metabolism, Reactive Oxygen Species/metabolism, Resting Phase, Retinoblastoma Protein/drug effects/metabolism, TNF-Related Apoptosis-Inducing Ligand, Transforming Growth Factor beta/*pharmacology, Transforming Growth Factor beta1, Tretinoin/*antagonists & inhibitors/pharmacology, Tumor Cells, Tumor Necrosis Factor-alpha/metabolism/pharmacology},

pubstate = {published},

tppubtype = {article}

}

@article{andrysik_activation_2006,

title = {Activation of ERK1/2 and p38 kinases by polycyclic aromatic hydrocarbons in rat liver epithelial cells is associated with induction of apoptosis.},

author = {Zdenek Andrysík and Miroslav Machala and Katerina Chramostová and Jirina Hofmanová and Alois Kozubík and Jan Vondrácek},

doi = {10.1016/j.taap.2005.06.007},

issn = {0041-008X},

year  = {2006},

date = {2006-03-01},

journal = {Toxicology and applied pharmacology},

volume = {211},

number = {3},

pages = {198–208},

abstract = {Deregulation of various signaling pathways, linked either to induction of cell proliferation or to modulation of cellular differentiation and apoptosis, has been proposed to contribute to carcinogenicity of polycyclic aromatic hydrocarbons (PAHs). In the present study, we investigated effects of the PAHs previously shown to induce cell proliferation and/or apoptosis in contact-inhibited rat liver epithelial WB-F344 cells, with an aim to define the role of mitogen-activated protein kinases in both events. We found that only strong genotoxin dibenzo[a,l]pyrene (DBalP) activated extracellular signal-regulated kinases 1 and 2 (ERK1/2) and p38 kinase, but not c-Jun N-terminal kinases (JNKs), at concentrations inducing both apoptosis and phosphorylation of p53 tumor suppressor at serine 15 residue. In contrast, the PAHs stimulating cell proliferation in WB-F344 cell line had no effect on activation of ERK1/2, p38 or JNKs. Synthetic inhibitors of ERK1/2 activation (U0126) or p38 kinase activity (SB203580) prevented both apoptosis and induction of p53 phosphorylation by DBalP. Pifithrin-alpha, inhibitor of p53 transcriptional activity, prevented induction of apoptosis and activation of ERK1/2 and p38. Taken together, our data suggest that both ERK1/2 and p38 are activated in response to DBalP and that they might be involved in regulation of cellular response to DNA damage induced by DBalP, while neither kinase is involved in the release from contact inhibition induced by PAHs.},

note = {Place: United States},

keywords = {*Epithelial Cells/cytology/drug effects/enzymology, *Liver/cytology/drug effects/enzymology, Animals, Apoptosis/*drug effects, Cell Cycle/drug effects, Cell Line, Cell Proliferation/drug effects, Enzyme Activation/drug effects, Enzyme Inhibitors/pharmacology, Extracellular Signal-Regulated MAP Kinases/*metabolism, JNK Mitogen-Activated Protein Kinases/metabolism, p38 Mitogen-Activated Protein Kinases/*metabolism, Phosphorylation, Polycyclic Aromatic Hydrocarbons/*toxicity, Rats},

pubstate = {published},

tppubtype = {article}

}