title: Comparison of the metabolic activation of environmental carcinogens in mouse embryonic stem cells and mouse embryonic fibroblasts.
abstract: We compared mouse embryonic stem (ES) cells and fibroblasts (MEFs) for their ability to metabolically activate the environmental carcinogens benzo[a]pyrene (BaP), 3-nitrobenzanthrone (3-NBA) and aristolochic acid I (AAI), measuring DNA adduct formation by (32)P-postlabelling and expression of xenobiotic-metabolism genes by quantitative real-time PCR. At 2 μM, BaP induced Cyp1a1 expression in MEFs to a much greater extent than in ES cells and formed 45 times more adducts. Nqo1 mRNA expression was increased by 3-NBA in both cell types but induction was higher in MEFs, as was adduct formation. For AAI, DNA binding was over 450 times higher in MEFs than in ES cells, although Nqo1 and Cyp1a1 transcriptional levels did not explain this difference. We found higher global methylation of DNA in ES cells than in MEFs, which suggests higher chromatin density and lower accessibility of the DNA to DNA damaging agents in ES cells. However, AAI treatment did not alter DNA methylation. Thus mouse ES cells and MEFs have the metabolic competence to activate a number of environmental carcinogens, but MEFs have lower global DNA methylation and higher metabolic capacity than mouse ES cells.
authors.affiliation: Analytical and Environmental Sciences Division, MRC-PHE Centre for Environment and Health, King's College London, London, United Kingdom.
authors.forename: Annette M
authors.initials: AM
authors.lastname: Krais
authors.affiliation: Research Group Genetic Alterations in Carcinogenesis, German Cancer Research Center (DKFZ), Heidelberg, Germany.
authors.forename: Karl-Rudolf
authors.initials: KR
authors.lastname: Mühlbauer
authors.affiliation: Analytical and Environmental Sciences Division, MRC-PHE Centre for Environment and Health, King's College London, London, United Kingdom.
authors.forename: Jill E
authors.initials: JE
authors.lastname: Kucab
authors.affiliation: Analytical and Environmental Sciences Division, MRC-PHE Centre for Environment and Health, King's College London, London, United Kingdom.
authors.forename: Helena
authors.initials: H
authors.lastname: Chinbuah
authors.affiliation: Research Group Genetic Alterations in Carcinogenesis, German Cancer Research Center (DKFZ), Heidelberg, Germany.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Cornelius
authors.affiliation: Research Group Genetic Alterations in Carcinogenesis, German Cancer Research Center (DKFZ), Heidelberg, Germany.
authors.forename: Quan-Xiang
authors.initials: QX
authors.lastname: Wei
authors.affiliation: Research Group Genetic Alterations in Carcinogenesis, German Cancer Research Center (DKFZ), Heidelberg, Germany; Molecular Mechanisms and Biomarkers Group, International Agency for Research on Cancer, Lyon, France.
authors.forename: Monica
authors.initials: M
authors.lastname: Hollstein
authors.affiliation: Analytical and Environmental Sciences Division, MRC-PHE Centre for Environment and Health, King's College London, London, United Kingdom.
authors.forename: David H
authors.initials: DH
authors.lastname: Phillips
authors.affiliation: Analytical and Environmental Sciences Division, MRC-PHE Centre for Environment and Health, King's College London, London, United Kingdom.
authors.forename: Volker M
authors.initials: VM
authors.lastname: Arlt
authors.affiliation: Research Group Genetic Alterations in Carcinogenesis, German Cancer Research Center (DKFZ), Heidelberg, Germany.
authors.forename: Heinz H
authors.initials: HH
authors.lastname: Schmeiser
mesh_terms: D000818:Animals; D034341:Aristolochic Acids / Q000378:metabolism / Q000494:pharmacology; D001551:Benz(a)Anthracenes / Q000378:metabolism / Q000494:pharmacology; D001564:Benzo(a)pyrene / Q000378:metabolism / Q000494:pharmacology; D015153:Blotting, Western; D002274:Carcinogens, Environmental / Q000378:metabolism / Q000494:pharmacology*; D018736:DNA Adducts / Q000032:analysis / Q000378:metabolism; D019175:DNA Methylation / Q000187:drug effects; D053595:Embryonic Stem Cells / Q000187:drug effects* / Q000378:metabolism; D005347:Fibroblasts / Q000187:drug effects* / Q000378:metabolism; D020869:Gene Expression Profiling; D051379:Mice; D008810:Mice, Inbred C57BL; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D034341:Aristolochic Acids; D001551:Benz(a)Anthracenes; D002274:Carcinogens, Environmental; D018736:DNA Adducts; D001564:Benzo(a)pyrene; C000228:aristolochic acid I; C117220:3-nitrobenzanthrone
keywords: Carcinogen activation; Cytochrome P450; DNA adduct formation; Mouse embryonic fibroblasts; Mouse embryonic stem cells; NADP(H)quinone oxidoreductase