The objective of this research is to evaluate cell energy status and redox status, as predictors of cellular response to heat, radiation (oxygen enhancement ratio), and the bioreductively activated drug, mitomycin C. Knowledge of these indices of metabolic status should be of use not only for predicting response to a particular therapeutic agent, but also for choosing treatment approaches, for a variety of human neoplasms. Energy and redox status will be determined by measuring the content of ATP, ADP, AMP, CrP, and NAD+, NADH, NADP+, NADPH, on a single extract of cells or tissue by high pressure liquid chromatography. Biochemical considerations and experimental evidence suggest that changes in tumor energy and redox status occur secondary to hypoxia, or hypoglycemia, or inadequate carbon sources for oxidative phosphorylation. In the proposed study, the relationship between variable oxygen, glucose, and amino acid concentration, and cell energy and redox status, will be evaluated. Simultaneously, the radiation oxygen enhancement ratio and cell sensitivity to fixed doses of heat, and mitomycin C will be evaluated. Specifically, the radiation oxygen enhancement ratio (OER) and parameters of metabolic status will be determined at 6-8 oxygen concentrations. Subsequently, the effect of prolonged oxygen depreviation, 100 PPM 02, on the OER, energy status, and redox status, will be determined. Cellular response to fixed doses of heat, radiation, and mitomycin C will be evaluated under restricted glucose and amino acid conditions. The relationship between energy and redox status and sensitivity of cells to these agents will be determined. It is anticipated that specific changes in energy and redox status will occur in response to each unique nutrient condition, and that these metabolic indices will be predictors of heat, radiation and drug sensitivity. In addition to these in vitro analyses on two cell lines, the murine FSa-II and human glioblastoma U87, both lines will be employed as poorly oxygenated FSa-II and well oxygenated U87 tumor models in C3H/Sed and NCr/Sed (nu/nu) mice. In these in vivo studies, redox status, energy status, hypoxic cell fraction and tumor sensitivity will be evaluated as a function of tumor volume. These studies will establish the utility of these parameters as predictors of heat, radiation (tumor hypoxia), and sensitivity to bioreductively activated drugs.
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