This application requests support for a Research Career Development Award for continuation of a systematic study of the role of dihydrodiol dehydrogenase in the detoxification of proximate and ultimate carcinogens of polycyclic aromatic hydrocarbons (PAH). The research programs includes chemical, biochemical, cellular and human studies designed to provide information on the role of this enzyme in PAH metabolism. We have shown that the homogeneous dihydrodiol dehydrogenase from rat liver cytosol oxidizes a variety of non-K-region-trans dihydrodiols of carcinogenic PAH to the corresponding ortho- quinones which can be trapped as mercaptoethanol adducts. To obtain information on this alternative pathway of proximate carcinogen metabolism, the reactivity of non-K-region ortho- quinone products towards cellular nucleophiles will be examined, the influence of bay-region methylation on reactivity will be determined, the ability of glutathione to enhance enzymatic rates of trans-dihydrodiol oxidation by trapping the ortho-quinone products will be assessed, structures of putative quinone- glutathione adducts will be elucidated, and the ability of these ortho-quinone products to act as substrates for highly purified preparations of rat liver glutathione transferases will be determined. The involvement of the homogeneous dihydrodiol dehydrogenase in ultimate carcinogen metabolism will be explored by using the stable anti-diol-epoxides of naphthalene and phenanthrene and the anti-diol epoxide of benzo(a)pyrene (BP) as substrates. Cellular studies will exploit the findings that the rat hepatoma cell line (H-4II-e) contains dihydrodiol dehydrogenase that is exquisitely sensitive to inhibition by indomethacin and 6- medroxyprogesterone acetate. By studying the metabolism of the (3H)-7,8-trans-dihydrodiol of BP in these cells, in the presence and absence of these drugs, the contribution of dihydrodiol dehydrogenase to the detoxification of PAH in whole cells will be assessed. If this enzyme plays a significant role these drugs should evaluate levels of anti-diol epoxides and BP-DNA adducts. To determine if dihydrodiol dehydrogenase plays a role in PAH metabolism in humans, liver autopsy samples will b analyzed for this enzyme activity, activities will be separated by chromatography and isozymes which oxidize the trans-7,8- dihydrodiol of BP will be characterized.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Modified Research Career Development Award (K04)
Project #
5K04CA001335-05
Application #
3071850
Study Section
Chemical Pathology Study Section (CPA)
Project Start
1988-02-01
Project End
1993-01-31
Budget Start
1992-04-03
Budget End
1993-01-31
Support Year
5
Fiscal Year
1992
Total Cost
Indirect Cost
Name
University of Pennsylvania
Department
Type
Schools of Medicine
DUNS #
042250712
City
Philadelphia
State
PA
Country
United States
Zip Code
19104
Flowers-Geary, L; Harvey, R G; Penning, T M (1993) Cytotoxicity of polycyclic aromatic hydrocarbon o-quinones in rat and human hepatoma cells. Chem Res Toxicol 6:252-60
Penning, T M (1993) Dihydrodiol dehydrogenase and its role in polycyclic aromatic hydrocarbon metabolism. Chem Biol Interact 89:1-34
Shou, M; Harvey, R G; Penning, T M (1993) Reactivity of benzo[a]pyrene-7,8-dione with DNA. Evidence for the formation of deoxyguanosine adducts. Carcinogenesis 14:475-82
Murty, V S; Penning, T M (1992) Polycyclic aromatic hydrocarbon (PAH) ortho-quinone conjugate chemistry: kinetics of thiol addition to PAH ortho-quinones and structures of thioether adducts of naphthalene-1,2-dione. Chem Biol Interact 84:169-88
Flowers-Geary, L; Harvey, R G; Penning, T M (1992) Examination of diols and diol epoxides of polycyclic aromatic hydrocarbons as substrates for rat liver dihydrodiol dehydrogenase. Chem Res Toxicol 5:576-83
Murty, V S; Penning, T M (1992) Characterization of mercapturic acid and glutathionyl conjugates of benzo[a]pyrene-7,8-dione by two-dimensional NMR. Bioconjug Chem 3:218-24
Penning, T M; Isaacson, K; Lyttle, C R (1992) Hormonal regulation of 3 alpha-hydroxysteroid/dihydrodiol dehydrogenase in rat liver cytosol. Biochem Pharmacol 43:1148-51
Shou, M; Harvey, R G; Penning, T M (1992) Contribution of dihydrodiol dehydrogenase to the metabolism of (+/-)-trans-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene in fortified rat liver subcellular fractions. Carcinogenesis 13:1575-82
Penning, T M; Ricigliano, J W (1991) Mechanism based inhibition of hydroxysteroid dehydrogenases. J Enzyme Inhib 5:165-98
Pawlowski, J; Huizinga, M; Penning, T M (1991) Isolation and partial characterization of a full-length cDNA clone for 3 alpha-hydroxysteroid dehydrogenase: a potential target enzyme for nonsteroidal anti-inflammatory drugs. Agents Actions 34:289-93

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