Carcinogenic 3-nitrobenzanthrone induces oxidative damage to isolated and cellular DNA.
3-Nitrobenzanthrone (3-NBA) is an extremely potent mutagen in diesel exhaust. It is a lung carcinogen to rats, and therefore a suspected carcinogen to human. In order to clarify the mechanism of carcinogenicity of 3-NBA, we investigated oxidative DNA damage by N-hydroxy-3-aminobenzanthrone (N-OH-ABA), a metabolite of 3-NBA, using 32P-labeled DNA fragments from the human p53 tumor-suppressor gene. N-OH-ABA caused Cu(II)-mediated DNA damage, and endogenous reductant NADH dramatically enhanced this process. Catalase and a Cu(I)-specific chelator decreased DNA damage, suggesting the involvement of hydrogen peroxide (H2O2) and Cu(I). N-OH-ABA induced DNA damage at cytosine and guanine residues of ACG sequence complementary to codon 273, a well-known hot spot of the p53 gene. N-OH-ABA dose dependently induced 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) formation in the presence of Cu(II) and NADH. Treatment with N-OH-ABA increased amounts of 8-oxodG in HL-60 cells compared to the H2O2-resistant clone HP100, supporting the involvement of H2O2. The present study has demonstrated that the N-hydroxy metabolite of 3-NBA induces oxidative DNA damage through H2O2 in both a cell-free system and cultured human cells. We conclude that oxidative DNA damage may play an important role in the carcinogenic process of 3-NBA in addition to previously reported DNA adduct formation.
Department of Environmental and Molecular Medicine, Mie University Graduate School of Medicine, Edobashi 2-174, Tsu, Mie 514-8507, Japan.
Mariko
M
Murata
Taro
T
Tezuka
Shiho
S
Ohnishi
Takeji
T
Takamura-Enya
Yoshiharu
Y
Hisamatsu
Shosuke
S
Kawanishi
D000080242:8-Hydroxy-2'-Deoxyguanosine; D001551:Benz(a)Anthracenes / Q000633:toxicity*; D002273:Carcinogens / Q000633:toxicity*; D002374:Catalase / Q000494:pharmacology; D002614:Chelating Agents / Q000494:pharmacology; D003300:Copper / Q000494:pharmacology; D004249:DNA Damage / Q000187:drug effects*; D003849:Deoxyguanosine / Q000031:analogs & derivatives / Q000378:metabolism; D016158:Genes, p53 / Q000187:drug effects; D011905:Genes, ras / Q000187:drug effects; D018922:HL-60 Cells; D006801:Humans; D009243:NAD / Q000378:metabolism; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000187:drug effects*; D010101:Oxygen Consumption / Q000187:drug effects; D010618:Phenanthrolines / Q000494:pharmacology; D013056:Spectrophotometry, Ultraviolet
D001551:Benz(a)Anthracenes; D002273:Carcinogens; D002614:Chelating Agents; C511206:N-hydroxy-2-aminobenzanthrone; D010618:Phenanthrolines; D009243:NAD; D003300:Copper; D000080242:8-Hydroxy-2'-Deoxyguanosine; C002478:bathocuproine; D002374:Catalase; D003849:Deoxyguanosine; C117220:3-nitrobenzanthrone