Nelson G, Ross JA, Pimentel M, Desai D, Sharma AK, Amin S, Nesnow S. Characterization of naphtho[1,2-a]pyrene and naphtho[1,2-e]pyrene DNA adducts in C3H10T1/2 fibroblasts.
Cancer Lett 2007;
247:309-17. [PMID:
16814461 DOI:
10.1016/j.canlet.2006.05.011]
[Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2006] [Revised: 05/19/2006] [Accepted: 05/22/2006] [Indexed: 10/24/2022]
Abstract
Polycyclic aromatic hydrocarbons (PAHs) are a class of carcinogenic chemicals that are ubiquitous in the environment. Fjord-region naphthopyrene isomers are structurally similar to the potent fjord-region PAH carcinogen dibenzo[a,l]pyrene and thus have the potential to be potent carcinogens. Naphtho[1,2-a]pyrene (N[1,2-a]P) exhibited similar bacterial mutagenicity and morphological cell transforming activity when compared to benzo[a]pyrene (B[a]P), whereas the structural isomer, naphtho[1,2-e]pyrene (N[1,2-e]P) was inactive is these bioassays. In this study, we examined the formation of DNA adducts in C3H10T1/2Cl8 (C3H10T1/2) mouse embryo fibroblasts exposed to N[1,2-a]P or N[1,2-e]P and their respective dihydrodiols. The DNA adducts were characterized by co-chromatography with reaction products from anti-N[1,2-a]P diol epoxide (DE) or anti-N[1,2-e]PDE and polydeoxyadenosine (dAdo) or oligodeoxyguanosine (dGuo). C3H10T1/2 fibroblasts exposed to N[1,2-a]P or N[1,2-a]P-9,10-diol produced both anti-N[1,2-a]P-DE-dAdo and -dGuo adducts with total DNA adduction levels of 22.2 to 33.3 pmol DNA adducts/mug DNA. C3H10T1/2 fibroblasts exposed to N[1,2-e]P produced 2 major and 1 minor adducts. C3H10T1/2 fibroblasts exposed to N[1,2-e]P-11,12-diol produced 2 major adducts. All of the identified adducts were anti-N[1,2-e]PDE-dGuo and -dAdo adducts. While the total DNA adduct level in N[1,2-e]P-11,12-diol-treated fibroblasts was extremely high, 105.9 pmol DNA adducts/mug DNA, the level in N[1,2-e]P-treated fibroblasts was 1.47 pmol DNA adducts/microg DNA. We conclude that lack of biological activity of N[1,2-e]P may be related to its inability to form sufficient amounts of N[1,2-e]P-11,12-diol, which would then be metabolized to sufficient amounts of anti-N[1,2-e]PDE needed to transform these fibroblasts.
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