nium - Responsive Proteins in the Sera of Selenium - iched Yeast – Supplemented Healthy African B & P erican and Caucasian

nloaded kground: Studies have shown that supplementation of adult men with selenium-enriched yeast (SY) rotective against prostate cancer (PCa) and also reduced oxidative stress and levels of prostatec antigen. Here, we determined the effect of SY supplementation on global serum protein expresn healthy men to provide new insights into the mechanism of selenium chemoprevention; such ns may also serve as biomarkers of disease progression. thods: Serum samples from 36 adult men were obtained from our previous SY clinical trial, 9 s after supplementation with either SY (247 μg/d; n = 17) or placebo (nonenriched yeast; n = 19). ults: Proteomic profiling using two-dimensional difference in gel electrophoresis followed by liquid atography-tandem mass spectrometry revealed a total of 1,496 candidate proteins, of which, 11 ifferentially expressed in the SY group as compared with placebo. Eight proteins were upregulated rin isoform 1 (CLU), transthyretin, α-1B-glycoprotein, transferrin, complement component 4B pron, isocitrate dehydrogenase, haptoglobin, and keratin 1] and three proteins were downregulated [α-1 psin (AAT), angiotensin precursor, and albumin precursor] by SY. All of the identified proteins edox-sensitive or involved in the regulation of redox status. Because both AAT and CLU have been usly linked to PCa development, their identities were confirmed by two-dimensional Western blot is. clusions: We identified AAT and CLU as potential candidate proteins involved in the mechanism of revention by SY. Collectively, proteins identified in this study might serve as potential new biomaror monitoring and comparing responses to selenium-based chemopreventive agents. kers f Impact: Proteomic analysis of serum might be useful for the early detection and monitoring efficacy of chemopreventive agents. Cancer Epidemiol Biomarkers Prev; 19(9); 2332–40. ©2010 AACR.