Prenatal exposure to soy and selenium reduces prostate cancer risk factors in TRAMP mice more than exposure beginning at six weeks.

Background: Diets high in soy and selenium (Se) decrease prostate cancer risk factors in healthy rats. The purpose of this study was to determine whether treatment with high levels of soy and/or supplemental Se would decrease prostate cancer risk factors in the Transgenic Adenocarcinoma of Mouse Prostate (TRAMP) mouse, and whether timing of the introduction of these nutrients would affect risk reduction.

Methods: Male hemizygous [C57BL/6 × FVB]F1 TRAMP mice were exposed to stock diets high or devoid of soy, with or without a supplement of Se-methylselenocysteine (MSC) starting at conception (10 mg Se/L in drinking water of pregnant/nursing dams; daily bolus of 4 mg Se/kg body weight to pups after weaning) or at 6 weeks of age in a 2 × 2 factorial design.

Combination effects of dietary soy and methylselenocysteine in a mouse model of prostate cancer.

Background: High dietary intake of soy or selenium (Se) is associated with decreased risk of prostate cancer. Soy constituents and various chemical forms of Se have each been shown to downregulate expression of the androgen receptor (AR) and AR-regulated genes in the prostate. We hypothesized that downregulation of AR and AR-regulated genes by the combination of these dietary components would inhibit tumorigenesis in the TRansgenic Adenocarcinoma of Mouse Prostate (TRAMP) mouse.

Soy content of basal diets determines the effects of supplemental selenium in male mice.

The effects of supplemental Se in rodent models may depend upon composition of the basal diet to which it is added. Wild-type male littermates of Transgenic Adenocarcinoma of Mouse Prostate mice were fed until 18 wk of age 1 of 2 Se-adequate stock diets high in soy (HS) or low in phytoestrogens (LP) or the same diets supplemented with 3.0 mg Se/kg diet as seleno-methylselenocysteine.