Influence of suppression of CapG gene expression by siRNA on the growth and metastasis of human prostate cancer cells.

This study investigated CapG gene expression in prostate cancer cell lines; in addition, we explored the effects of CapG suppression on DU145 cell growth, and the underlying mechanism with which CapG affects DU145 cell growth and invasiveness. The expression of CapG and 18 related genes in DU145 cells was analyzed by flow cytometry, quantitative polymerase chain reaction (qPCR), CCK8 assay, western blot, and the trans-well assay. DU145 cells were transfected with designed small interfering RNA (siRNA). CapG expression was quantified by qPCR and western blot. DU145 cell proliferation and invasiveness was analyzed using the CCK8, flow cytometric, and trans-well assays. CapG, TMPRSS1, EGFR, ETS-1, ERBB2, AKT, Cyclin D1, P21, Bcl-2, and Bak1 gene and Bcl-2, Cyclin D1, and CapG protein expressions were significantly lower in the siRNA group compared to the negative control group (P < 0.05). The proliferation of CapG siRNA DU145 cells was lower than that of the two control groups, 48 h after transfection. The cell inhibition rate was 24.5, 35.4, and 16,5% at 24, 48, and 72 h, respectively. The growth curve indicated that CapG siRNA DU145 cells showed a significantly slower proliferation rate (P < 0.05). The trans-well assay showed a significant decrease in the migratory and invasive capacities of DU145 cells in the siRNA group (P < 0.05). The suppression of CapG expression caused a significant decrease in the proliferation, invasiveness, and metastasis of DU145 cells. The mechanism with which CapG, with other oncogenes, influences cancer cell cycle remains to be elucidated.