Expression of resistin in the prostate and its stimulatory effect on prostate cancer cell proliferation

OBJECTIVES To determine whether resistin, a novel adipokine, induces prostate cancer cell proliferation. To identify the mechanisms underlying the activation of prostate cancer cells by resistin. MATERIALS AND METHODS Semi-quantitative reverse transcriptase-polymerase chain reaction and immunohistochemical staining were performed to investigate the intensity of prostate epithelial resistin expression. Human full-length resistin gene (RETN) was transfected into the PC-3 cells using the pEGFP-N1 vector to assess the effect of overexpression of resistin in prostate cancer cell line PC-3. Various concentrations of human recombinant protein resistin were added to the hormone-insensitive prostate cancer cell lines PC-3 and DU-145 for 48 h, and cell proliferation was assessed by a water-soluble tetrazolium salt assay. RESULTS Human prostate cancer cell lines PC-3 and DU-145 were found to express the human resistin mRNA. Resistin protein was strongly detected in high-grade prostate cancer tissue, whereas BPH or low-grade prostate cancer tissue revealed fainter expression of resistin. Cell proliferation was stimulated by both the full-length resistin gene overexpression and resistin treatment. Akt phosphorylation occurred after addition of resistin to PC-3 and DU-145 cells. LY294002, a pharmacological inhibitor of phosphatidylinositol 3-kinase (PI3K), significantly inhibited PC-3 and DU-145 cell proliferation after resistin treatment. CONCLUSIONS Resistin is expressed in human prostate cancers. Resistin induces prostate cancer cell proliferation through PI3K/Akt signalling pathways. The proliferative effect of resistin on prostate cancer cells may account in part for prostate cancer progression.