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{stika_mk-886_2006,

title = {MK-886 enhances tumour necrosis factor-alpha-induced differentiation and apoptosis.},

author = {Jirí Stika and Jan Vondrácek and Jirina Hofmanová and Vladimír Simek and Alois Kozubík},

doi = {10.1016/j.canlet.2005.06.012},

issn = {0304-3835},

year  = {2006},

date = {2006-06-01},

journal = {Cancer letters},

volume = {237},

number = {2},

pages = {263–271},

abstract = {We investigated the role of the 5-lipoxygenase (5-LOX) pathway of arachidonic acid metabolism in tumour necrosis factor-alpha (TNF-alpha)-induced differentiation of human leukemic HL-60 cells using MK-886, an inhibitor of 5-LOX activating protein. MK-886 augmented cell cycle arrest and differentiation induced by TNF-alpha; however, both effects were probably 5-LOX-independent, because a general LOX inhibitor, NDGA, had no effect. Apoptosis was significantly elevated after combined TNF-alpha and MK-886 treatment, which could be partially associated with changes of Mcl-1 protein expression. NF-kappaB signalling or activation of JNKs were not modulated by MK-886. Thus, in addition to apoptosis, MK-886 can enhance TNF-alpha-induced differentiation.},

note = {Place: Ireland},

keywords = {*Apoptosis, Arachidonate 5-Lipoxygenase/metabolism, Cell Cycle, Cell Differentiation, Cell Line, Cell Survival, HL-60 Cells, Humans, Indoles/*pharmacology, Lipoxygenase Inhibitors/*pharmacology, Signal Transduction, Time Factors, Tumor, Tumor Necrosis Factor-alpha/*metabolism},

pubstate = {published},

tppubtype = {article}

}

@article{vondracek_dimethyl_2006,

title = {Dimethyl sulfoxide potentiates death receptor-mediated apoptosis in the human myeloid leukemia U937 cell line through enhancement of mitochondrial membrane depolarization.},

author = {Jan Vondrácek and Karel Soucek and Michael A. Sheard and Katerina Chramostová and Zdenek Andrysík and Jirina Hofmanová and Alois Kozubík},

doi = {10.1016/j.leukres.2005.05.016},

issn = {0145-2126},

year  = {2006},

date = {2006-01-01},

journal = {Leukemia research},

volume = {30},

number = {1},

pages = {81–89},

abstract = {Dimethyl sulfoxide (DMSO) is a widely used prototypical chemical inducer of cell differentiation. In the present study, the effects of DMSO on susceptibility of human myeloid leukemia U937 cells towards ligation of distinct death receptors (DRs) were investigated. DMSO sensitized cells towards induction of apoptosis by anti-Fas antibody, tumour necrosis factor-alpha or Apo2 ligand/TNF-related apoptosis-inducing ligand (TRAIL). Apart from increasing Fas levels, DMSO did not affect expression of proteins in death signal transduction, such as Bcl-2 family proteins, FADD, caspase-3 and -8, the inhibitor of apoptosis proteins (IAPs) or cFLIP(L). However, DMSO significantly potentiated mitochondrial membrane depolarization, suggesting that this mechanism might be involved in sensitisation of myeloid cells to DR-mediated apoptosis.},

note = {Place: England},

keywords = {Adaptor Proteins, Apoptosis Regulatory Proteins/*metabolism, Apoptosis/*drug effects, CASP8 and FADD-Like Apoptosis Regulating Protein, Caspase 3, Caspase 8, Caspases/metabolism, Cryoprotective Agents/*pharmacology, Dimethyl Sulfoxide/*pharmacology, fas Receptor/*metabolism, Fas-Associated Death Domain Protein, Humans, Intracellular Signaling Peptides and Proteins, Leukemia, Membrane Glycoproteins/*metabolism, Mitochondria/metabolism/pathology, Mitochondrial Membranes/*metabolism/pathology, Myeloid/*metabolism/pathology, Proto-Oncogene Proteins c-bcl-2/metabolism, Signal Transducing/metabolism, TNF-Related Apoptosis-Inducing Ligand, Tumor Necrosis Factor-alpha/*metabolism, U937 Cells},

pubstate = {published},

tppubtype = {article}

}