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Quantification of benzo[ a ]pyrene diol epoxide DNA‐adducts by stable isotope dilution liquid chromatography/tandem mass spectrometry
Author(s) -
Ruan Qian,
Kim HyeYoung H.,
Jiang Hao,
Penning Trevor M.,
Harvey Ronald G.,
Blair Ian A.
Publication year - 2006
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.2457
Subject(s) - chemistry , isotope dilution , chromatography , benzo(a)pyrene , epoxide , adduct , mass spectrometry , tandem mass spectrometry , liquid chromatography–mass spectrometry , diol , pyrene , organic chemistry , catalysis
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental pollutants found in car exhausts, charbroiled food, and tobacco smoke. Three pathways for the metabolic activation of B[ a ]P to ultimate carcinogens have been proposed. The most widely accepted pathway involves cytochrome‐P450 (CYP) 1A1‐ and/or 1B1‐mediated formation of B[ a ]P‐7,8‐oxide, which undergoes epoxide hydrolase‐mediated metabolism to the proximate carcinogen B[ a ]P‐7,8‐dihydro‐7,8‐diol. Further CYP1A1‐ and/or CYP1B1‐mediated activation of the dihydrodiol results in the formation of 7,8‐dihydroxy‐9,10‐epoxy‐7,8,9,10‐tetrahydrobenzo[ a ]pyrene (B[ a ]PDE), the ultimate carcinogen. In previous studies, it was demonstrated that (+)‐ anti‐ B[ a ]PDE was the most potent tumorigen of the CYP‐derived B[ a ]PDE diastereomers. We have developed a stable isotope dilution, liquid chromatography multiple reaction monitoring/mass spectrometry (LC‐MRM/MS) assay for all eight (±)‐ anti ‐B[ a ]PDE‐derived dGuo and dAdo DNA‐adducts. The LC‐MRM/MS assay was rigorously validated and used to show that (+)‐ anti‐trans ‐B[ a ]PDE‐dGuo was the major adduct formed when naked DNA and human bronchoalveolar adenocarcinoma H358 cells were treated with (±)‐ anti ‐B[ a ]PDE. The preference for DNA‐adducts derived from (+)‐ anti ‐B[ a ]PDE was even more apparent in cellular DNA. Thus, the increased potency of (+)‐ anti ‐B[ a ]PDE as a tumorigen is most likely due its ability to preferentially form DNA‐adducts when compared with (−)‐ anti ‐B[ a ]PDE. Also, the adduct profile suggests that this occurs by binding of (+)‐ anti ‐B[ a ]PDE to DNA in a manner that facilitates covalent binding to dGuo rather than dAdo residues. Copyright © 2006 John Wiley & Sons, Ltd.