title: Double base lesions of DNA by a metabolite of carcinogenic benzo[a]pyrene.
abstract: Carcinogenic benzo[a]pyrene (BP) is generally considered to show genotoxicity by forming DNA adducts of its metabolite, BP-7,8-diol-9,10-epoxide. We investigated oxidative DNA damage and its sequence specificity induced by BP-7,8-dione, another metabolite of BP, using (32)P-5'-end-labeled DNA. Formamidopyrimidine-DNA glycosylase treatment induced cleavage sites mainly at G residues of 5'-TG-3' sequence and at poly(C) sequences, in DNA incubated with BP-7,8-dione in the presence of NADH and Cu(II), whereas piperidine treatment induced cleavage sites at T mainly of 5'-TG-3'. BP-7,8-dione strongly damaged the G and C of the ACG sequence complementary to codon 273 of the p53 gene. Catalase and a Cu(I)-specific chelator attenuated the DNA damage, indicating the involvement of H(2)O(2) and Cu(I). BP-7,8-dione with NADH and Cu(II) also increased 8-oxo-7,8-dihydro-2'-deoxyguanosine formation. We conclude that oxidative DNA damage, especially double base lesions, may participate in the expression of carcinogenicity of BP in addition to DNA adduct formation.
authors.affiliation: Department of Hygiene, Mie University School of Medicine, 2-174, Edobashi, Tsu, Mie, 514-8507, Japan.
authors.forename: Shiho
authors.initials: S
authors.lastname: Ohnishi
authors.forename: Shosuke
authors.initials: S
authors.lastname: Kawanishi
mesh_terms: D000080242:8-Hydroxy-2'-Deoxyguanosine; D000447:Aldehydes / Q000737:chemistry / Q000494:pharmacology; D000818:Animals; D001580:Benzopyrenes / Q000737:chemistry* / Q000494:pharmacology; D001665:Binding Sites / Q000187:drug effects; D002273:Carcinogens / Q000737:chemistry* / Q000494:pharmacology; D002417:Cattle; D003300:Copper / Q000737:chemistry; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000235:genetics; D004247:DNA / Q000737:chemistry* / Q000187:drug effects; D004249:DNA Damage; D043382:DNA-Formamidopyrimidine Glycosylase; D003849:Deoxyguanosine / Q000031:analogs & derivatives / Q000032:analysis; D016166:Free Radical Scavengers / Q000737:chemistry; D016158:Genes, p53 / Q000187:drug effects; D011905:Genes, ras / Q000187:drug effects; D006801:Humans; D009699:N-Glycosyl Hydrolases / Q000737:chemistry; D009243:NAD / Q000737:chemistry; D010084:Oxidation-Reduction / Q000187:drug effects; D010880:Piperidines / Q000737:chemistry
chemical_list: D000447:Aldehydes; D001580:Benzopyrenes; D002273:Carcinogens; D019941:Cyclin-Dependent Kinase Inhibitor p16; D016166:Free Radical Scavengers; D010880:Piperidines; C008390:methional; D009243:NAD; C076588:benzo(a)pyrene-7,8-dione; C032727:piperidine; D003300:Copper; D000080242:8-Hydroxy-2'-Deoxyguanosine; D004247:DNA; D009699:N-Glycosyl Hydrolases; D043382:DNA-Formamidopyrimidine Glycosylase; D003849:Deoxyguanosine