Knockdown of lipocalin-2 suppresses the growth and invasion of prostate cancer cells

BACKGROUND. Lipocalin-2 (LCN2) is a member of the lipocalin superfamily, and it has an important role in the regulation of cellular oncogenesis and apoptosis. However, the role for LCN2 in prostate cancer remains unclear. METHOD. LCN2 expression has been determined by Western blotting, qRT-PCR, and immunohistochemistry in the human prostate cell lines PC3, DU145, LNCaP, and 22Rv, and in human prostate tissue array. In this study, we identified shRNA-LCN2 to determine the role of LCN2 in prostate-cancer cell proliferation, migration, and invasion. Cell proliferative ability was measured by MTT, colony-formation, and cell-cycle analysis. The role of LCN2 in prostate-cancer cell migration and invasion was analyzed by cell-migration assay and Matrigel invasion assay. The effect of LCN2 knockdown on prostate tumor growth was assessed in a subcutaneous xenograft model. RESULTS. LCN2 protein and mRNA expression are higher in PC3 and DU145 cells than in LNCaP and 22Rv cells, and prostate cancer tissue correlated significantly with tumor differentiation (P<0.017) and Gleason's grade (P<0.02). LCN2 knockdown in PC3 and DU145 cells decreased cell proliferation, colony formation, cell cycle arrest, migration, and invasion. Conversely, LCN2 overexpression in 22Rv cells produced the opposite effect. Subcutaneous xenografts in mice models showed decreased tumor growth in the LCN2-knockdown mice. CONCLUSIONS. Our results suggest that LCN2 might play an important role in regulation of proliferation and invasion of human prostate cancer, and that it can be a valuable marker of prostate cancer progression. Prostate 73: 1281-1290, 2013. (c) 2013 Wiley Periodicals, Inc.