Latest Publications

@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{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}

}