Trace Elements and the Development of Prostate Cancer

Abstract : Selenium is an essential nutrient that may have an important preventive action in prostate cancer. We have identified a human gene in prostate cells, designated hSP56, the mouse homologue of which may mediate selenium's growth inhibitory effect in vitro and anti-cancer effect in vivo. hSP56 is expressed by LNCaP but not by PC-3 and is reversibly downregulated by androgen. We hypothesize that hSP56 protein may play a role in the anti-cancer effects of selenium in the prostate gland. To test this hypothesis we will: 1) study the molecular properties of hSP56 protein, including its binding of selenium, 2) study the role of hSP56 in the prostate cancer phenotype in vitro using gain-of-function and low-of-function approaches, 3) investigate the effect of overexpression or downregulation of hSP56 on in vivo tumor growth in SCID mice and 4) determine the distribution of hSP56 expression in primary human tumors and in adjacent normal prostate cancer cells. This work will lead to a new understanding of prostate cancer regulation and the role of selenium in normal and malignant prostate growth and spread.