title: Nutritional and supranutritional levels of selenate differentially suppress prostate tumor growth in adult but not young nude mice.
abstract: The inhibitory effect of oral methylseleninic acid or methylselenocysteine administration on cancer cell xenograft development in nude mice is well characterized; however, less is known about the efficacy of selenate and age on selenium chemoprevention. In this study, we tested whether selenate and duration on diets would regulate prostate cancer xenograft in nude mice. Thirty-nine homozygous NU/J nude mice were fed a selenium-deficient, Torula yeast basal diet alone (Se-) or supplemented with 0.15 (Se) or 1.0 (Se+) mg selenium/kg (as Na₂SeO₄) for 6 months in Experiment 1 and for 4 weeks in Experiment 2, followed by a 47-day PC-3 prostate cancer cell xenograft on the designated diet. In Experiment 1, the Se- diet enhanced the initial tumor development on days 11-17, whereas the Se+ diet suppressed tumor growth on days 35-47 in adult nude mice. Tumors grown in Se- mice were loosely packed and showed increased necrosis and inflammation as compared to those in Se and Se+ mice. In Experiment 2, dietary selenium did not affect tumor development or histopathology throughout the time course. In both experiments, postmortem plasma selenium concentrations in Se and Se+ mice were comparable and were twofold greater than those in Se- mice. Taken together, dietary selenate at nutritional and supranutritional levels differentially inhibit tumor development in adult, but not young, nude mice engrafted with PC-3 prostate cancer cells.
authors.affiliation: Department of Nutrition and Food Science, University of Maryland, College Park, MD 20742, USA.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Holmstrom
authors.forename: Ryan T Y
authors.initials: RT
authors.lastname: Wu
authors.forename: Huawei
authors.initials: H
authors.lastname: Zeng
authors.forename: K Y
authors.initials: KY
authors.lastname: Lei
authors.forename: Wen-Hsing
authors.initials: WH
authors.lastname: Cheng
mesh_terms: D000375:Aging; D000818:Animals; D016588:Anticarcinogenic Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D045744:Cell Line, Tumor; D019587:Dietary Supplements; D006801:Humans; D008297:Male; D051379:Mice; D008819:Mice, Nude; D009336:Necrosis; D011471:Prostatic Neoplasms / Q000209:etiology / Q000276:immunology / Q000473:pathology / Q000517:prevention & control*; D011897:Random Allocation; D064586:Selenic Acid; D012643:Selenium / Q000097:blood / Q000172:deficiency; D018036:Selenium Compounds / Q000008:administration & dosage / Q000627:therapeutic use*; D013997:Time Factors; D047368:Tumor Burden; D015431:Weight Loss; D023041:Xenograft Model Antitumor Assays
chemical_list: D016588:Anticarcinogenic Agents; D018036:Selenium Compounds; D012643:Selenium; D064586:Selenic Acid