title: Prenatal exposure to soy and selenium reduces prostate cancer risk factors in TRAMP mice more than exposure beginning at six weeks.
abstract: 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. Mice were killed at 12 weeks (n per dietary treatment = 20-30).
  
  
  RESULTS
  Liver and serum Se concentrations were increased by MSC supplementation (P < 0.001), high-soy diet (P < 0.05), and initiation of dietary treatments at conception (P < 0.05). MSC supplementation had greater effects in mice fed the zero-soy basal diet, compared to the high-soy formulation (Pinteraction  < 0.01). These same three interventions, individually and interactively, decreased body weight and epididymal fat pad weights, and steady state levels of mRNA for Cyp19a1 (aromatase) and Srd5a1 (5α-reductase). In contrast, MSC was the only treatment that decreased urogenital tract weights (P < 0.001), serum IGF-1 levels (P < 0.002), and Gleason scores (P < 0.05).
  
  
  CONCLUSIONS
  Supplemental MSC reduces risk of prostate cancer in TRAMP mice. Basal diet composition (zero- vs. high-soy) can modify MSC's chemopreventive effects. Initiation of dietary treatments from conception maximizes chemopreventive effects of MSC. Prenatal Se status may have long-lasting effects on development and progression of prostate cancer.
authors.affiliation: Department of Nutrition, Dietetics, and Food Science, Brigham Young University, Provo, Utah.
authors.forename: Heather L
authors.initials: HL
authors.lastname: Nakken
authors.affiliation: Department of Physiology and Developmental Biology, Brigham Young University, Provo, Utah.
authors.forename: Edwin D
authors.initials: ED
authors.lastname: Lephart
authors.affiliation: Department of Nutrition, Dietetics, and Food Science, Brigham Young University, Provo, Utah.
authors.forename: Tyler J
authors.initials: TJ
authors.lastname: Hopkins
authors.affiliation: Department of Nutrition, Dietetics, and Food Science, Brigham Young University, Provo, Utah.
authors.forename: Brett
authors.initials: B
authors.lastname: Shaw
authors.affiliation: Utah Valley Regional Medical Center, Provo, Utah.
authors.forename: Paul M
authors.initials: PM
authors.lastname: Urie
authors.affiliation: Department of Nutrition, Dietetics, and Food Science, Brigham Young University, Provo, Utah.|Simmons Center for Cancer Research, Brigham Young University, Provo, Utah.
authors.forename: Merrill J
authors.initials: MJ
authors.lastname: Christensen
mesh_terms: D000818:Animals; D016588:Anticarcinogenic Agents / Q000494:pharmacology; D018890:Chemoprevention / Q000379:methods; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D005260:Female; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D011471:Prostatic Neoplasms / Q000178:diet therapy / Q000473:pathology / Q000517:prevention & control; D065840:Protective Factors; D012643:Selenium / Q000494:pharmacology*; D045730:Soy Foods
chemical_list: D016588:Anticarcinogenic Agents; D012643:Selenium
keywords: TRAMP; prenatal; prostate cancer; selenium; soy