Ji Su Park, Brigham Young University
Nutrition, Dietetics, and Food Science
Selenium (Se) and soy have each been shown to reduce risk for prostate cancer when consumed at high levels. The purpose of this project was to define the molecular mechanisms of prostate cancer chemoprevention by Se and soy, and to describe how timing of dietary treatment modifies those effects. [C57BL/6 X FVB] F1 TRAMP (TRansgenic Adenocarcinoma of Mouse Prostate) male mice were fed stock diets high or low in soy, with or without a supplement of Se (4.0 mg Se/kg BW as Se-meth- ylselenocysteine) by gavage 5 d/wk in a 2 X 2 factorial design. Mice were exposed to different diets starting from conception, 6 weeks, or 12 weeks of age and were sacrificed at 18 weeks. Three-way ANOVA showed that supplemental Se increased serum and liver Se, with significant interactions with both time and soy intake. Selenium dosing decreased BW independent of soy intake and time of dietary intervention. Both Se and soy decreased epididymal fat pad weights, with Se’s effects being more pronounced in mice exposed to diets from conception than from 6 wk. Urogenital tract weights, a measure of prostate proliferation and tumor volume, were significantly reduced by Se supplementation (P<0.001) and soy (p=0.044), independent of time of dietary intervention. Histological examination of mouse prostates is in progress to determine dietary effects on disease progression. These data suggest that, in this model, chemopreventive efficacy of Se and soy does not differ between prenatal and early post-natal introduction.