Protection against Radiation-Induced Carcinogenesis

Division Of Basic Sciences - Nci

Investigators

Linked publications, trials & patents

Abstract

We have finished a study exploring the influence of the gut microflora on radiation-induced carcinogenesis. The animal's gut microflora composition was modulated by use of an antibiotic cocktail in the drinking water prior to whole body radiation. We found that reducing the gut microflora 3 weeks before total body radiation (TBI) resulted in shortened lifespan of mice compared to TBI alone, demonstrating the importance of the gut microflora in radiation-induced carcinogenesis. Two life span studies in mice exposed to non-lethal 3 Gy TBI with and without rapamycin in their chow. The chow was administered after the TBI. Three different concentrations (14, 40, and 140 mg/kg) of rapamycin were placed in the chow. The number of mice receiving control chow was 50 and those receiving TBI had 100 mice per group. The results clearly show that all three concentrations rapamycin protected against TBI-induced carcinogenesis and prolonged life. The data show that rapamycin treatment extended the life span of mice compared to TBI alone by in large part decreasing the induction of hepatocellular carcinomas. Since rapamycin is FDA approved for use in humans, the protection it provides to radiation-induced carcinogenesis makes it a reasonable candidate for humans exposed to non-lethal TBI.