ObjectiveTo investigate the potential role of the RhoA/Rock signaling pathway in the formation of prostate cancer and the effects of the Rock inhibitor fasudil on the invasion, migration and apoptosis of human prostate cancer cells.

METHODSHuman prostate cancer cell lines PC3 and DU145 were treated with fasudil at the concentrations of 5, 10, 20, 40, 80, and 160 μmol/L, respectively, and those as negative controls cultured in the Ham's-F12 medium, all for 24 hours. Then, MTT assay was used to measure the cell inhibition rate and half maximal inhibitory concentration (IC50) value of fasudil, with 1/4 of IC50 as the medication dose for further investigation. The expressions of RhoA, RockⅠ, and RockⅡ proteins in the PC3 and DU145 cells were detected by Western blot and immunohistochemistry, and the invasion, migration and apoptosis of the cells were determined using the Transwell chamber, scratch wound healing assay and flow cytometry.

RESULTSFasudil inhibited the proliferation of the PC3 cells from (9.29±1.23)% at 5 μmol/L to (81.37±3.97)% at 160 μmol/L and that of DU145 from (7.59±1.54)% to (76.53±2.67)%, both in a dose-dependent manner (P<0.05 ). Significantly fewer PC3 and DU145 cells migrated into the lower compartment in the experimental group (39.2±8.4 and 34.2±6.7) than in the negative control (116.8±9.3 and 112.5±10.8) (P<0.05 ). The wound healing rates of the PC3 and DU145 cells were remarkably lower in the former (［37.26±1.17］% and ［32.38±2.73］%) than in the latter (［78.12±4.16］% and ［69.47±6.71］%) (P<0.05 ). Annexin V-FITC/PI double staining showed markedly increased apoptosis rates of PC3 and DU145 cells treated with fasudil (［31.88±2.49］% and ［28.65±2.99］%) as compared with the negative controls (［7.51±2.28］% and ［7.13±1.61］%) (P<0.05 ). The expressions of RockⅠ and RockⅡ were significantly reduced in the fasudil-treated cells in comparison with those of the control group (P<0.05 ) while that of RhoA showed no significant difference between the two groups (P>0.05 ).

CONCLUSIONSThe RhoA/Rock signaling pathway may play an important role in the formation of prostate cancer. Fasudil can significantly inhibit the proliferation, migration, and invasion and promote the apoptosis of human prostate cancer PC3 and DU145 cells by reducing RhoA/Rho kinase activity.