Effects of Silencing EZH2 Gene Expression on Proliferation and Apoptosis of Human Renal Carcinoma Cell Lines

Objective To explore the effect of silencing EZH2 expression on the proliferation and apoptosis of human ACHN renal cell carcinoma(RCC) cell lines by RNA interference. Methods The expression profiles of EZH2 protein in normal human proximal kidney tubular epithelial cell line HK-2, RCC cell line 786-0 and ACHN were detected by Western blot. The small interfering RNA(siRNA) was synthesized and mtransfected into ACHN cell line with Lipofectamin2000 for silencing the expression of EZH2. Western blot was used to detect the validity of RNAi on downregulating protein expression of EZH2 in transfected cells. Then the CCK-8 assay was performed for assessing cell proliferation and flow cytometry assay was used to detect cell cycle and apoptosis. Results EZH2 protein expression in 786-0 and ACHN cell lines were in higher levels than those in normal human kidney HK-2 cell line. The protein expression level of EZH2 was effectively downregulated by siRNA. The proliferation rate of ACHN cell transfected with siEZH2 was significantly decreased, especially at 48 and 72h post-transfection(P＜0.05). The flow cytometry analysis showed that there was an increase of cell number at G1 phase and a decrease of cell number at S and G2 phases in ACHN cells transfected with siEZH2, especially at 48h after transfection(P＜0.05). Further apoptosis analysis showed that there was an increase of apoptosis rate of siEZH2-transfected ACHN cells in a timedependent manner, especially at 48 and 72h post-transfection(P＜0.05). Conclusion Knockdown of EZH2 expression by RNAi could inhibit cell cycle progress by arresting cell cycle at G1/S checkpoint, and led to reduced proliferation and increased apoptosis of ACHN RCC cells.