Objective To clarify the significance of RNF180 expression in carcinogenesis and progression of prostate cancer by detection of RNF180 promoter methylation. Methods RNF180 expression was detected in human prostate cancer cell lines(PC3,LNCap,and DU145)and normal prostate cells(RWPE?1)via Western blotting,RT?PCR,methylation?specific PCR(MSP),bisulfite?sequeneing PCR(BSP),respectively, while RNF180 expression in human prostate cancer tissues and paired adjacent non?tumor tissue was detected via immunohistochemistry. Results The expressions of RNF180 mRNA and protein in prostate cancer cells were significantly lower than those in normal prostate cells(P<0.05),op?posite to what was observed for the methylation level of the RNF180 promoter. Additionally,the RNF180 expression in prostate cancer tissue was significantly lower than that in paired adjacent non?tumor tissue. Conclusion The RNF180 promoter is incompletely methylated in prostate can?cer cells,which may be a reason for the decline or silencing of RNF180 expression in cancer cells and tissues.

Objective To investigate the mechanism and cause of the inactivation of tumor suppressor gene RNF180 in prostate cancer cell line by observing the effect of 5-Aza-CdR on the RNF180 gene in prostate cancer cell line DU145. Methods MTT method was adopted to study the effect of 5-Aza-CdR(0,1,2,5,10,15 and 20μmoI/L)on the proliferation of prostate cancer cells. Western blotting,real-time PCR,and methyla-tion specific PCR(MSP)were separately used to detect the expression of RNF180 in prostate cancer cells before and after the treatment of the most suitable drug concentration(5μmoI/L). Results In a certain range,the effect of 5-Aza-CdR on the proliferation of prostate cancer cell line DU145 was increased with the increase of drug concentration and the time of drug treatment(P<0.05). After the treatment of the most suitable drug concentration,the protein and mRNA expression of RNF180 in prostate cancer cells was significantly increased(P<0.05),but the methyla-tion of the promoter region was obviously decreased. Conclusion 5-Aza-CdR can reverse the methylation status of RNF180 gene in DU145 pros-tate cancer cell line,and relieve the silencing status of RNF180gene expression.