EZH2 Regulates The Growth Of Renal Cell Carcinoma Cells And Influences The Prognosis Of Renal Cancer

Partâ… Correlation of EZH2 and E-cadherin Gene Expression and its Clinical Prognostic SignificanceObjective:To investigate the expression and significance of EZH2 and E-cadherin in renal cell carcinoma (RCC) and ascertain whether its expression profiles are impact on the outcome in patients with RCC.Methods:EZH2 mRNA and protein in RCC tissue were detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot methods, respectively. Immunohistochemistry was performed to detect the EZH2 and E-cadherin protein expression in the RCC tumor tissues. The impact of EZH2 and E-cadherin expression on RCC clinicopathological tumor features was analyzed. The significance of EZH2 and E-cadherin expression for prognosis was investigated by Kaplan-Meier curves and Cox proportional hazards analysis in a multivariate model.Results:EZH2 mRNA and protein expression in normal renal tissue were in a very low level, the positive expression rate was 16.67%, whereas its expression in RCC tissue was upregulated and the positive expression rate was 78.12%. Meanwhile, the EZH2 expression was strongly associated with clinical stage, pathological grade and lymph node metastasis status of RCC. There were significant differences in E-cadherin expression between normal renal and RCC tissues, with positive rate of 75.0% and 26.56%, respectively. The expression level of E-cadherin showed a statistically significant difference in RCC groups with different clinical stage, pathological grade and lymph node metastasis status. The expression of EZH2 was negatively correlated with E-cadherin expression level. The Univariate analysis resulted showed that high EZH2 levels predicted a shorter median disease-free survival (DFS) and lower DFS rate, whereas high E-cadherin levels predicted a longer median DFS and higher DFS rate. It implicated that EZH2 and E-cadherin expression were significant prognostic factors for RCC. However, multivariate analysis showed that EZH2 and E-cadherin were not the independent risk factors for RCC.Conclusion:The abnormal expression of EZH2 and E-cadherin may play a crucial impact on RCC tumorigenesis and tumor clinical progression. While EZH2 and E-cadherin were significant prognostic factors for RCC, they were not the independent parameter for outcome prediction in patient with RCC. Accordingly, we should perform further investigation to identify the prognostic value of EZH2 and E-cadherin for renal cell carcinoma. Partâ…¡Silencing of EZH2 Gene in Human RCC Cell by RNAi and its Effect on Cell Proliferation and ApoptosisObjective:To determine the expression pattern of EZH2 in human RCC cells and to explore the effect on the proliferation and apoptosis of human ACHN RCC cell line after silencing of EZH2 by RNA interference.Methods:The expression profiles of EZH2 mRNA and protein on HK-2,786-0 and ACHN cell lines were detected by RT-PCR and Western blot methods, respectively. The small interfering RNA (siRNA) was synthesized and transfected into human ACHN RCC 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 cell apoptosis.Results:EZH2 mRNA and protein expression on human RCC 786-0 and ACHN cell lines were in higher levels versus 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 48h and 72h post-transfection (P<0.05). The flow cytometric analysis showed that there was an increase of cell number at G1 phase and a decrease of cell number at S and G2 phase in ACHN cells transfected with siEZH2, especially at 48h after transfection (P<0.05). Further apoptosis analysis showed that EZH2 silence by RNAi enhanced cell apoptosis remarkably, there was an increase of apoptosis rate in transfected ACHN cells (P<0.05). Thus, inhibition of EZH2 expression by RNAi inhibited cell cycle progress by arresting cell cycle at G1/S checkpoint, and led to reduced proliferation and increased apoptosis in ACHN RCC cell.Conclusion:Knockdown of EZH2 expression can inhibit cell proliferation by arresting cell cycle progression at G1/S restriction point and enhance cell apoptosis. Therefore, targeted silence of EZH2 expression may represent a novel promising strategy for the gene therapy of RCC.