title: Deregulation of cancer-related pathways in primary hepatocytes derived from DNA repair-deficient Xpa-/-p53+/- mice upon exposure to benzo[a]pyrene.
abstract: The current method to predict carcinogenicity of chemicals or drugs is the chronic 2-year rodent bioassay, which has disadvantages in duration, animal use, and specificity. An attractive alternative is the DNA repair-deficient Xpa(-/-)p53(+/-) mouse model that is sensitive to both genotoxic and nongenotoxic carcinogens. A next step in alternative carcinogenicity testing is the development of reliable in vitro systems. We investigated the use of primary hepatocytes, isolated from wild-type (WT) and Xpa(-/-)p53(+/-) mice, in combination with transcriptome analyses for their usefulness to predict carcinogenic features of compounds. As a proof of principle, we studied the response of hepatocytes to the genotoxic carcinogen benzo[a]pyrene (B[a]P). Upon treatment, both WT and Xpa(-/-)p53(+/-) hepatocytes appeared to be metabolically active. However, Xpa(-/-)p53(+/-) hepatocytes were more sensitive than WT hepatocytes to B[a]P treatment in terms of cell survival. In B[a]P-treated WT hepatocytes, DNA repair and cell cycle control genes were transcriptionally activated. Xpa(-/-)p53(+/-) hepatocytes were more responsive to B[a]P exposure, resulting in the downregulation of cancer-related pathways. Deregulation of mitogen-activated protein kinase signaling seems to play an essential role in this and might be the underlying reason for the increased susceptibility of Xpa(-/-)p53(+/-) mice toward carcinogens. Our conclusion is that primary hepatocytes combined with transcriptomics are promising to identify the carcinogenic features of chemicals. Furthermore, these cells seem suitable to gain further insight into the molecular mechanisms of the increased sensitivity of Xpa(-/-)p53(+/-) mice toward both genotoxic and nongenotoxic carcinogens.
authors.affiliation: Laboratory for Health Protection Research, National Institute for Public Health and the Environment, 3720 BA Bilthoven, The Netherlands.
authors.forename: Petra C E
authors.initials: PC
authors.lastname: van Kesteren
authors.forename: P Edwin
authors.initials: PE
authors.lastname: Zwart
authors.forename: Jeroen L A
authors.initials: JL
authors.lastname: Pennings
authors.forename: W H Ralph
authors.initials: WH
authors.lastname: Gottschalk
authors.forename: Jos C S
authors.initials: JC
authors.lastname: Kleinjans
authors.forename: Joost H
authors.initials: JH
authors.lastname: van Delft
authors.forename: Harry
authors.initials: H
authors.lastname: van Steeg
authors.forename: Mirjam
authors.initials: M
authors.lastname: Luijten
mesh_terms: D000818:Animals; D001564:Benzo(a)pyrene / Q000633:toxicity*; D015197:Carcinogenicity Tests / Q000379:methods; D002273:Carcinogens / Q000633:toxicity*; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D019363:Cytochrome P-450 CYP1A1 / Q000378:metabolism; D004260:DNA Repair / Q000187:drug effects / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D016158:Genes, p53 / Q000187:drug effects*; D022781:Hepatocytes / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D043922:Toxicogenetics; D051760:Xeroderma Pigmentosum Group A Protein / Q000187:drug effects* / Q000235:genetics
chemical_list: D002273:Carcinogens; D051760:Xeroderma Pigmentosum Group A Protein; C497315:Xpa protein, mouse; D001564:Benzo(a)pyrene; D019363:Cytochrome P-450 CYP1A1