乳腺癌患者血清miR-29c与miR-200a表达相关性及其机制研究

Correlation of miR-29c and miR-200a Expression and Mechanism Exploration in Breast Cancer

目的探究miR-29c与miR-200a表达的相关性及其机制,为乳腺癌早期诊断及预防提供新的分子标志物及治疗靶点.方法通过荧光定量PCR检测乳腺癌患者miR-29c、miR-200a的表达并分析其相关性;同时将人工合成的miR-29c模拟体转染到乳腺癌细胞MCF-7内,应用实时荧光定量PCR检测两种微小RNA表达量的变化,重亚硫酸氢盐测序法检测miR-29c转染组、阴性对照组、DNA甲基化抑制剂5-Aza-CdR处理组的miR-200a启动子区甲基化水平.结果实时荧光定量PCR结果显示,乳腺癌患者血清中miR-29c与miR-200a的表达存在正相关关系(r=0.63,P<0.01).与阴性对照组比较,miR-29c模拟体转染组的miR-200a的相对表达量显著增高(P<0.05);重亚硫酸盐测序结果显示,与NC组比较,miR-29c模拟体转染组miR-200a基因的甲基化程度明显降低,与5-Aza-CdR处理组的甲基化水平相近.结论miR-29c与miR-200a的表达具有相关性,miR-29c通过影响DNA甲基化水平而增加miR-200a的表达.

Objective To explore the relationship of miR-29c and miR-200a expression in the serum of the breast cancer patients and its mechanism,and provide new molecular markers and therapeutic targets for breast cancer.Method The expression of miR-29c and miR-200a were detected with real time PCR.At the same time,the miR-29c mimics were transfected into MCF-7 cells,the miR-200a promoter methylation levels of the cells transfected with/without miR-29c mimics and 5-Aza-CdR were evaluated with bisulfite PCR sequencing method,respectively.Results Real-time PCR results showed that the expression of miR-200a is correlated with the expression of miR-29c in the serum of the patients with breast cancer(r=0.63,P<0.01).Compared with the negative control group,miR-29c mimics increased the expression of miR-200a significantly(P<0.05),then bisulfite sequencing PCR result showed that the methylation level of miR-200a promoter was significantly lower in the MCF-7 cells transfected with miR-29c mimics comparing with negative control group,which was near to that of the cells treated with 5-Aza-CdR,DNA methyltransferase inhibitor.Conclusion miR-29c expression associated with miR-200a,miR-29c affected the expression of miR-200a by altering the level of DNA methylation of its promoter.