2015
Kabátková, Markéta; Zapletal, Ondřej; Tylichová, Zuzana; Neča, Jiří; Machala, Miroslav; Milcová, Alena; Topinka, Jan; Kozubík, Alois; Vondráček, Jan
Inhibition of β-catenin signalling promotes DNA damage elicited by benzo[a]pyrene in a model of human colon cancer cells via CYP1 deregulation. Journal Article
In: Mutagenesis, vol. 30, no. 4, pp. 565–576, 2015, ISSN: 1464-3804 0267-8357, (Place: England).
Abstract | Links | BibTeX | Tags: *DNA Damage, Apoptosis, Aryl Hydrocarbon/genetics/metabolism, Benzo(a)pyrene/*adverse effects, beta Catenin/*antagonists & inhibitors/genetics/metabolism, Blotting, Carcinogens, Cell Proliferation, Colonic Neoplasms/drug therapy/*etiology/*pathology, Cultured, Cytochrome P-450 CYP1A1/antagonists & inhibitors/genetics/*metabolism, DNA Adducts/*adverse effects, Environmental/adverse effects, Enzymologic/*drug effects, Gene Expression Regulation, Humans, Immunoenzyme Techniques, Messenger/genetics, Neoplastic/*drug effects, Real-Time Polymerase Chain Reaction, Receptors, Reverse Transcriptase Polymerase Chain Reaction, RNA, Small Interfering/genetics, Tumor Cells, Western
@article{kabatkova_inhibition_2015,
title = {Inhibition of β-catenin signalling promotes DNA damage elicited by benzo[a]pyrene in a model of human colon cancer cells via CYP1 deregulation.},
author = {Markéta Kabátková and Ondřej Zapletal and Zuzana Tylichová and Jiří Neča and Miroslav Machala and Alena Milcová and Jan Topinka and Alois Kozubík and Jan Vondráček},
doi = {10.1093/mutage/gev019},
issn = {1464-3804 0267-8357},
year = {2015},
date = {2015-07-01},
journal = {Mutagenesis},
volume = {30},
number = {4},
pages = {565–576},
abstract = {Deregulation of Wnt/β-catenin signalling plays an important role in the pathogenesis of colorectal cancer. Interestingly, this pathway has been recently implicated in transcriptional control of cytochrome P450 (CYP) family 1 enzymes, which are responsible for bioactivation of a number of dietary carcinogens. In the present study, we investigated the impact of inhibition of Wnt/β-catenin pathway on metabolism and genotoxicity of benzo[a]pyrene (BaP), a highly mutagenic polycyclic aromatic hydrocarbon and an efficient ligand of the aryl hydrocarbon receptor, which is known as a primary regulator of CYP1 expression, in cellular models derived from colorectal tumours. We observed that a synthetic inhibitor of β-catenin, JW74, significantly increased formation of BaP-induced DNA adducts in both colorectal adenoma and carcinoma-derived cell lines. Using the short interfering RNA (siRNA) targeting β-catenin, we then found that β-catenin knockdown in HCT116 colon carcinoma cells significantly enhanced formation of covalent DNA adducts by BaP and histone H2AX phosphorylation, as detected by (32)P-postlabelling technique and immunocytochemistry, respectively, and it also induced expression of DNA damage response genes, such as CDKN1A or DDB2. The increased formation of DNA adducts formed by BaP upon β-catenin knockdown corresponded with enhanced production of major BaP metabolites, as well as with an increased expression/activity of CYP1 enzymes. Finally, using siRNA-mediated knockdown of CYP1A1, we confirmed that this enzyme plays a major role in formation of BaP-induced DNA adducts in HCT116 cells. Taken together, the present results indicated that the siRNA-mediated inhibition of β-catenin signalling, which is aberrantly activated in a majority of colorectal cancers, modulated genotoxicity of dietary carcinogen BaP in colon cell model in vitro, via a mechanism involving up-regulation of CYP1 expression and activity.},
note = {Place: England},
keywords = {*DNA Damage, Apoptosis, Aryl Hydrocarbon/genetics/metabolism, Benzo(a)pyrene/*adverse effects, beta Catenin/*antagonists & inhibitors/genetics/metabolism, Blotting, Carcinogens, Cell Proliferation, Colonic Neoplasms/drug therapy/*etiology/*pathology, Cultured, Cytochrome P-450 CYP1A1/antagonists & inhibitors/genetics/*metabolism, DNA Adducts/*adverse effects, Environmental/adverse effects, Enzymologic/*drug effects, Gene Expression Regulation, Humans, Immunoenzyme Techniques, Messenger/genetics, Neoplastic/*drug effects, Real-Time Polymerase Chain Reaction, Receptors, Reverse Transcriptase Polymerase Chain Reaction, RNA, Small Interfering/genetics, Tumor Cells, Western},
pubstate = {published},
tppubtype = {article}
}
Deregulation of Wnt/β-catenin signalling plays an important role in the pathogenesis of colorectal cancer. Interestingly, this pathway has been recently implicated in transcriptional control of cytochrome P450 (CYP) family 1 enzymes, which are responsible for bioactivation of a number of dietary carcinogens. In the present study, we investigated the impact of inhibition of Wnt/β-catenin pathway on metabolism and genotoxicity of benzo[a]pyrene (BaP), a highly mutagenic polycyclic aromatic hydrocarbon and an efficient ligand of the aryl hydrocarbon receptor, which is known as a primary regulator of CYP1 expression, in cellular models derived from colorectal tumours. We observed that a synthetic inhibitor of β-catenin, JW74, significantly increased formation of BaP-induced DNA adducts in both colorectal adenoma and carcinoma-derived cell lines. Using the short interfering RNA (siRNA) targeting β-catenin, we then found that β-catenin knockdown in HCT116 colon carcinoma cells significantly enhanced formation of covalent DNA adducts by BaP and histone H2AX phosphorylation, as detected by (32)P-postlabelling technique and immunocytochemistry, respectively, and it also induced expression of DNA damage response genes, such as CDKN1A or DDB2. The increased formation of DNA adducts formed by BaP upon β-catenin knockdown corresponded with enhanced production of major BaP metabolites, as well as with an increased expression/activity of CYP1 enzymes. Finally, using siRNA-mediated knockdown of CYP1A1, we confirmed that this enzyme plays a major role in formation of BaP-induced DNA adducts in HCT116 cells. Taken together, the present results indicated that the siRNA-mediated inhibition of β-catenin signalling, which is aberrantly activated in a majority of colorectal cancers, modulated genotoxicity of dietary carcinogen BaP in colon cell model in vitro, via a mechanism involving up-regulation of CYP1 expression and activity.
2007
Umannová, Lenka; Zatloukalová, Jirina; Machala, Miroslav; Krcmár, Pavel; Májková, Zuzana; Hennig, Bernhard; Kozubík, Alois; Vondrácek, Jan
In: Toxicological sciences : an official journal of the Society of Toxicology, vol. 99, no. 1, pp. 79–89, 2007, ISSN: 1096-6080 1096-0929, (Place: United States).
Abstract | Links | BibTeX | Tags: Animals, Aryl Hydrocarbon Hydroxylases/genetics/*metabolism, Aryl Hydrocarbon/*drug effects/metabolism, Carcinogens/metabolism/toxicity, Cell Proliferation/drug effects, Cells, Cultured, Cytochrome P-450 CYP1A1/genetics/metabolism, Cytochrome P-450 CYP1B1, Dose-Response Relationship, Drug, Drug Combinations, Drug Interactions, Enzymologic/*drug effects, Epithelial Cells/drug effects/enzymology, Gene Expression Regulation, Inbred F344, Ligands, Liver/cytology, Polychlorinated Biphenyls/metabolism/*toxicity, Polychlorinated Dibenzodioxins/metabolism/*toxicity, Rats, Receptors, Stem Cells/*drug effects/enzymology, Tumor Necrosis Factor-alpha/*pharmacology
@article{umannova_tumor_2007,
title = {Tumor necrosis factor-alpha modulates effects of aryl hydrocarbon receptor ligands on cell proliferation and expression of cytochrome P450 enzymes in rat liver "stem-like" cells.},
author = {Lenka Umannová and Jirina Zatloukalová and Miroslav Machala and Pavel Krcmár and Zuzana Májková and Bernhard Hennig and Alois Kozubík and Jan Vondrácek},
doi = {10.1093/toxsci/kfm149},
issn = {1096-6080 1096-0929},
year = {2007},
date = {2007-09-01},
journal = {Toxicological sciences : an official journal of the Society of Toxicology},
volume = {99},
number = {1},
pages = {79–89},
abstract = {Various liver diseases lead to an extensive inflammatory response and release of a number of proinflammatory cytokines, such as tumor necrosis factor-alpha (TNF-alpha). This cytokine is known to play a major role in liver regeneration as well as in carcinogenesis. We investigated possible interactions of TNF-alpha with ligands of the aryl hydrocarbon receptor (AhR) and known liver carcinogens, such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and coplanar 3,3',4,4',5-pentachlorobiphenyl (PCB 126). These compounds have been previously found to disrupt cell cycle control in contact-inhibited rat liver WB-F344 cells, an in vitro model of adult liver progenitor cells. TNF-alpha itself had no significant effect on the proliferation/apoptosis ratio in the WB-F344 cell line. However, it significantly potentiated proliferative effects of low picomolar range doses of both TCDD and PCB 126, leading to an increase in cell numbers, as well as an increased percentage of cells entering the S-phase of the cell cycle. The combination of TNF-alpha with low concentrations of AhR ligands increased both messenger RNA (mRNA) and protein levels of cyclin A, a principle cyclin involved in disruption of contact inhibition. TNF-alpha temporarily inhibited AhR-dependent induction of cytochrome P450 1A1 (CYP1A1). In contrast, TNF-alpha significantly enhanced induction of CYP1B1 at both mRNA and protein levels, by a mechanism, which was independent of nuclear factor-kappaB activation. These results suggest that TNF-alpha can significantly amplify effects of AhR ligands on deregulation of cell proliferation control, as well as on expression of CYP1B1, which is involved in metabolic activation of a number of mutagenic compounds.},
note = {Place: United States},
keywords = {Animals, Aryl Hydrocarbon Hydroxylases/genetics/*metabolism, Aryl Hydrocarbon/*drug effects/metabolism, Carcinogens/metabolism/toxicity, Cell Proliferation/drug effects, Cells, Cultured, Cytochrome P-450 CYP1A1/genetics/metabolism, Cytochrome P-450 CYP1B1, Dose-Response Relationship, Drug, Drug Combinations, Drug Interactions, Enzymologic/*drug effects, Epithelial Cells/drug effects/enzymology, Gene Expression Regulation, Inbred F344, Ligands, Liver/cytology, Polychlorinated Biphenyls/metabolism/*toxicity, Polychlorinated Dibenzodioxins/metabolism/*toxicity, Rats, Receptors, Stem Cells/*drug effects/enzymology, Tumor Necrosis Factor-alpha/*pharmacology},
pubstate = {published},
tppubtype = {article}
}
Various liver diseases lead to an extensive inflammatory response and release of a number of proinflammatory cytokines, such as tumor necrosis factor-alpha (TNF-alpha). This cytokine is known to play a major role in liver regeneration as well as in carcinogenesis. We investigated possible interactions of TNF-alpha with ligands of the aryl hydrocarbon receptor (AhR) and known liver carcinogens, such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and coplanar 3,3',4,4',5-pentachlorobiphenyl (PCB 126). These compounds have been previously found to disrupt cell cycle control in contact-inhibited rat liver WB-F344 cells, an in vitro model of adult liver progenitor cells. TNF-alpha itself had no significant effect on the proliferation/apoptosis ratio in the WB-F344 cell line. However, it significantly potentiated proliferative effects of low picomolar range doses of both TCDD and PCB 126, leading to an increase in cell numbers, as well as an increased percentage of cells entering the S-phase of the cell cycle. The combination of TNF-alpha with low concentrations of AhR ligands increased both messenger RNA (mRNA) and protein levels of cyclin A, a principle cyclin involved in disruption of contact inhibition. TNF-alpha temporarily inhibited AhR-dependent induction of cytochrome P450 1A1 (CYP1A1). In contrast, TNF-alpha significantly enhanced induction of CYP1B1 at both mRNA and protein levels, by a mechanism, which was independent of nuclear factor-kappaB activation. These results suggest that TNF-alpha can significantly amplify effects of AhR ligands on deregulation of cell proliferation control, as well as on expression of CYP1B1, which is involved in metabolic activation of a number of mutagenic compounds.