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{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}

}

@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{vondracek_modulation_2002,

title = {Modulation of estrogen receptor-dependent reporter construct activation and G0/G1-S-phase transition by polycyclic aromatic hydrocarbons in human breast carcinoma MCF-7 cells.},

author = {Jan Vondrácek and Alois Kozubík and Miroslav Machala},

doi = {10.1093/toxsci/70.2.193},

issn = {1096-6080 1096-0929},

year  = {2002},

date = {2002-12-01},

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

volume = {70},

number = {2},

pages = {193–201},

abstract = {It has been suggested that the estrogenicity of PAHs could contribute to their carcinogenic effects via increased tissue-specific cell proliferation. Both benzo[a]pyrene (BaP) and benz[a]anthracene (BaA) are known to weakly activate estrogen receptor (ER)-dependent reporter constructs. In this study, several other PAHs, including fluorene, fluoranthene, pyrene, chrysene, phenanthrene and anthracene, were found to act as very weak inducers of ER-mediated activity in the MCF-7 cell line stably transfected with a luciferase reporter gene. The effects of PAHs were time-dependent and they were not completely inhibited by antiestrogen ICI 182,780. In addition, BaP and BaA, as well as weakly estrogenic fluoranthene, significantly potentiated the maximum ER-mediated activity of 17beta-estradiol. Therefore, the effects of inhibitors of several types of protein kinases known to activate ERalpha in a ligand-independent manner were investigated. However, neither inhibitors nor inducers of extracellular signal-regulated kinases 1 and 2 (ERK1/2), phosphatidylinositol-3 kinase, protein kinase C, c-Src, or protein kinase A modified ER-mediated activity in this model. Neither estradiol nor BaA activated ERK1/2, two kinases suggested to play significant roles in ER signaling, suggesting that another kinase is involved in the observed phosphorylation of ERalpha. Similar to 17beta-estradiol, BaA stimulated G(0)/G(1)-S-phase transition in MCF-7 cells, which was fully suppressed by ICI 182,780. In conclusion, some PAHs can potentiate 17beta-estradiol-induced ER activation and stimulate cell cycle entry in vitro. However, their exact mode(s) of action and whether this phenomenon is of in vivo relevance remains to be elucidated.},

note = {Place: United States},

keywords = {Breast Neoplasms/*metabolism, Cell Cycle/*drug effects/genetics, Cell Cycle/drug effects/genetics, Cultured, Estrogen Receptor alpha, Estrogen Receptor Modulators/pharmacology, Estrogen/genetics/*metabolism, G1 Phase/drug effects/genetics, Genes, Genetic/drug effects, Humans, Phosphorylation/drug effects, Polycyclic Aromatic Hydrocarbons/metabolism/*toxicity, Receptors, Reporter/*genetics, Resting Phase, S Phase/drug effects/genetics, Transcription, Tumor Cells},

pubstate = {published},

tppubtype = {article}

}