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Structure-function dependence and allopurinol inhibition of ratiosensitizer/nitroreductase interaction: approaches to improving therapeutic rations

Journal Article · · Cancer Clin. Trials; (United States)
OSTI ID:5298358
Normal tissue toxicity of nitroaromatic radiosensitizers may originate in radiosensitizer/nitroreductase interaction. A study of two mammalian cell nitroreductases, xanthine oxidase and NADH cytochrome c reductase, shows that the efficiency of electron transfer is dependent on sensitizer electron affinity and not lipid solubility. Misonidazole and its demethylated metabolite (RO-05-9963), for example, are equally efficient as electron acceptors from xanthine oxidase. The only exception to the electron affinity correlation is m-nitrobenzamidine hydrochloride xanthine oxidase from its cofactor, xanthine. Allopurinol inhibits electron transfer and might be a useful adjuvant to the nitroreductases in vivo is deduced from the observation that allopurinol significantly alters the serum lifetimes in mice of misonidazole and RO-05-9963.
Research Organization:
Cross Cancer Inst., Edmonton, Canada
OSTI ID:
5298358
Journal Information:
Cancer Clin. Trials; (United States), Journal Name: Cancer Clin. Trials; (United States) Vol. 3:1; ISSN CCTRD
Country of Publication:
United States
Language:
English