ADVANCED BIOMONITORING TECHNIQUES FOR CARCINOGENESIS

University Of Nebraska Medical Center, Omaha NE

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Abstract

There are two long-term objectives of the proposed research. The first is to use existing high resolution/sensitivity laser-induced fluorescence and separation techniques and new methodologies being developed to arrive at a firm, molecular level understanding of the mutagenic and tumorigenic activity of carcinogens (whether endogenous or exogenous) initiated by DNA adduct formation. Here, the study of DNA repair would also be important. The second is the development of clinically useful biomarker-technologies for risk assessment. There are four specific aims, all of which are related to the carcinogenic activity of metabolites formed from estrogens and/or polycyclic aromatic hydrocarbons (PAH). Aim 1: Development of monoclonal antibody-gold biosensor chips for detection and quantitation of biomarkers produced by covalent binding of catechol estrogen and PAH metabolites to DNA. Detection limits will be established with urine samples spiked with selected PAH- and catechol- estrogen quinone (CEQ)-derived DNA adducts and/or conjugates. Aim 2: Characterization and determination of DNA adducts formed from catechol estrogens of particular interest are 4-hydroxyesterone carcinogens (4-OHE1) and 4-hydroxyestradiol (4-OHE2) since they have been proposed to be potent endogenous carcinogens. The corresponding glutathione (GSH)- conjugates produced by a major detoxification pathway (and their breakdown products (e.g. 4-OHE2-N-acetylated cysteine [4-OHE2-2-(NAcCys]) will also be studied since they may serve as surrogates for DNA damage from depurination of the CEQ-DNA adducts. Urine of rodents and humans will be analyzed for the presence of 4-OHE2-2-NAcCys that is stable in urine. When possible, natural luminescence at cryogenic temperatures coupled with separation techniques will be used for analysis. Weakly luminescent adducts will e detected and identified by tagging with strong fluorophores. Aim 3: Develop and evaluate fluorescence affinity probe capillary electrophoresis (FAPCE) for the detection and quantitation of non- or weakly fluorescent CEQ-DNA adducts and 4-OPHE2-2-NAcCys. In principle, FAPCE is a simpler, more practical and more sensitive approach than derivatization of adducts with fluorescent tags. Aim 4: Provide analytical support for studies related to the effect of bulky sequence specific stable DNA adducts on the repair of apurinic (AP) sites produced by adducts formed by the one-electron oxidation pathway for PAH (Project 3).