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CHARACTERIZATION OF STABLE BENZOLALPYRENE-7,8-QUINONE-DNA ADDUCTS IN CALF THYMUS DNA AND POLYDEOXYNUCLEOTIDES
Ross, J A., G B. Nelson, W. T. Padgett, N Balu, G. R. Lambert, AND S Nesnow. CHARACTERIZATION OF STABLE BENZOLALPYRENE-7,8-QUINONE-DNA ADDUCTS IN CALF THYMUS DNA AND POLYDEOXYNUCLEOTIDES. Presented at American Association for Cancer Research, Anaheim, CA, April 16-20, 2005.
Bcnzo[a]pyrene-7,8-dione (BPQ) is a reactive aldo-keto reductase-mediated product of B[a]P-7,8-diol, a major P450/epoxide hydrolase metabolite of the multi-species carcinogen, B[a]P. The role of BPQ in B[a]P's genotoxicity and carcinogenesis is evolving. Toxicity pathways involving BPQ include the formation of both stable and unstable DNA adducts and the generation of ROS via redox cycling. To investigate the stable DNA adduct pathway, we have synthesized nucleotide-3'-phosphate-BPQ DNA adduct standards and applied these to the characterization of BPQ-DNA adducts in calf thymus DNA
(CT-DNA) using 32P-postlabeling analyses. Previously, we reported the full characterization of four BPQ-dGuo and two BPQ-dAdo nucleoside adducts [Balu et al. (2004) Chem. Res. Tox, 17, 827-838]. Using similar methods of syntheses and analyses we prepared the analogous BPQ-nucleotide adducts. BPQ was incubated with CT-DNA for 24 h at 37 ?C. 32P-Postlabeling analysis showed the formation of 5 major and 7 minor DNA adducts. Adducts were also observed following the postlabeling of synthesized 3'-dGMP-BPQ and 3'-dAMP-BPQ standards. The 3'-dGMP-BPQ1.2 standard exhibited 2 major adducts. The 3'-dGMP-BPQ3,4 standard exhibited 2 major and one minor adduct. One major and one minor adduct were observed in both the 3'dAMP-BPQ1 and the 3'-dAMP-BPQ2 standards. One adduct from the 3'-dGMP-BPQ3,4 standard co-chromatographed with a major CT-DNA adduct. Adducts from the 3'-dAMP-BPQI and 3'-dAMP-BPQ2 standards appear to co-chromatograph with several of the minor CT-DNA DNA adducts. Additional reactions of BPQ with poly-dA, poly-dC, and poly dG each resulted in detectable adducts, some of which were also formed in CT-DNA. This is the first reported example of the characterization of stable BPQ-DNA adducts in mammalian DNA and will serve as the foundation for future BPQ-DNA adduct studies in vivo.
Record Details:Record Type: DOCUMENT (PRESENTATION/ABSTRACT)
Organization:U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF RESEARCH AND DEVELOPMENT
NATIONAL HEALTH AND ENVIRONMENTAL EFFECTS RESEARCH LABORATORY
ENVIRONMENTAL CARCINOGENESIS DIVISION
CANCER BIOLOGY BRANCH