Physical activity and prostate gene expression in men with low-risk prostate cancer.

189 Background: Physical activity (PA), in particular longer duration or higher intensity, may reduce the risk of PCa progression and PCa-specific mortality in men diagnosed with clinically localized PCa. However, the molecular mechanism(s) by which PA exerts its protective effect in the prostate remains unknown. We examined the correlation of PA and gene expression patterns in men with low risk prostate cancer who elected to undergo active surveillance. Methods: Morphologically normal prostate tissue was obtained from men who subsequently participated in a clinical trial focused on nutritional supplements (previously published microarray dataset #GSE27140). Of the original sample (n=84), 70 completed a brief PA questionnaire and were dichotomized based usual PA [e.g. any vigorous PA (yes/no), 3+ h/wk vigorous PA (yes/no)]. Differential expression and pathway (gene set) analyses between groups were performed using Significance Analysis of Microarrays. Genes and gene sets with a false discovery rate ≤0.10 and 0.20 were considered significant, respectively. Results: Gene expression analysis detected 184 significant genes that were differentially expressed between men who performed vigorous PA for 3+ h/wk (n=23) and those who did not (n= 47). Up-regulated genes included the known tumor suppressors, BRCA1 and BRCA2. Furthermore, pathway analysis revealed that cell cycle and DNA repair pathways were positively modulated in men who participated in 3+h/wk vigorous PA vs. not. Consistent with the data on vigorous PA and clinical outcomes in men with PCa, the duration of vigorous PA was important; there were no significant genes detected when comparing men who participated in any vigorous PA to men who did none. Conclusions: Prostate gene expression and pathway analyses revealed candidate genes and in vivo pathways that may be modulated by participating in 3+ h/wk of vigorous PA. These data provide mechanistic insight into how 3+ h/wk of vigorous PA may offer PCa-specific benefits. Furthermore, understanding the molecular mechanisms by which such PA affects normal prostate gene expression may aid the development of strategies to prevent or delay PCa progression.