Regulation of prostate cancer cell migration toward bone marrow stromal cell-conditioned medium by Wnt5a signaling

Bone is a major site of metastasis for several types of malignant tumor. Specific interactions between tumor cells and the bone microenvironment contribute to the tendency of tumors to metastasize to bone. Furthermore, Wnt5a participates in the progression of several types of malignant tumor. This study investigates the role of Wnt5a in the migration of the prostate cancer (PCa) cell line PC3 toward bone marrow stromal cell (BMSC)-conditioned medium (CM). The expression of 22 genes associated with bone metastasis was measured in three PCa cell lines (LNCaP, PC3 and DU145). Subsequently, the proliferation and migration capacities of PC3 cells treated either with small interfering RNA (siRNA) against Wnt5a or with recombinant mouse (rm) Wnt5a were analyzed with alamarBlue and transwell assays. BMSC-CM was collected to evaluate its effect on PC3 cell migration. Also, the expression of Wnt5a in BMSCs was knocked down prior to collection of the CM to evaluate its effects on the migration of PC3 cells. Significantly higher levels of Wnt5a mRNA expression were identified in the PC3 cells, compared with those in LNCaP and DU145 cells. Silencing Wnt5a expression with siRNA reduced the migration capacity of PC3 cells by 50%. The addition of rmWnt5a improved the migration capacity of PC3 cells in a concentration-dependent manner. PC3 cells preferred to migrate toward BMSC-CM than toward the control. CM from Wnt5a siRNA-treated BMSCs significantly reduced PC3 cell migration. Wnt5a promotes PC3 cell migration toward BMSC-CM, indicating that Wnt5a is a potential therapeutic target for the treatment of advanced PCa.