胃癌中miR-148a通过DNMT1调控E-cadherin的表达

目的:研究胃癌中miR-148a与E-钙黏蛋白(E-cadherin)表达的相关性,并进一步探索miR-148a对E-cadherin的内在调控机制?方法:通过qRT-PCR或Western blot检测胃癌组织中E-cadherin及miR-148a的表达,使用Pearson相关分析检测E-cadherin与miR-148a表达的相关性;通过去甲基化药物处理,研究启动子异常甲基化与E-cadherin表达的关系;通过转染miR-148a mimics 提高miR-148a的表达水平,转染DNA化转移酶1(DNMT1)siRNA干扰DNMT1的表达水平,进一步研究miR-148a对E-cadherin的调控机制?结果:与正常胃黏膜相比,E-cadherin的mRNA及蛋白表达水平在胃癌组织中显著下调,并与miR-148a的表达呈正相关?去甲基化药物5-aza-dC处理后,胃癌细胞MGC-803及SGC-7901中E-cadherin的mRNA及蛋白表达水平显著上升?胃癌细胞转染miR-148a mimics后,E-cadherin的蛋白表达水平明显提高,并且干扰DNMT1的表达后,E-cadherin的蛋白表达水平也显著上调?结论:miR-148a能通过DNMT1进一步调控E-cadherin的表达?

miR-148a modulates E-cadherin in gastric cancer by targeting DNA methyltransferase

Objective:To investigate the correlation between E-cadherin and miR-148a,and explore the underlying mechanism of miR-148a regulating E-cadherin expression in gastric cancer. Methods:The mRNA levels of E-cadherin and miR-148a were detected by qRT-PCR,and protein expression of E-cadherin was assayed by Western blot;A correlation between E-cadherin mRNA levels and that of miR-148a in gastric cancer was investigated by Pearson correlation analyses;The relationship between aberrant methylation and E-cadherin expression was evaluated by treatment of gastric cancer cells with demethylation drug;The regulatory mechanism of miR-148a modulating E-cadherin was analyzed by transfection of gastric cancer cells with miR-148a mimics or DNA methyltransferase 1 (DNMT1) siRNA. Results:The mRNA and protein levels of E-cadherin were significantly downregulated in gastric cancer tissues compared with corresponding normal tissues,and were positively correlated with miR-148a expression. After treatment of MGC-803 and SGC-7901 cells with 5-aza-dC, a significant increase in E-cadherin mRNA and protein levels was observed. Moreover,overexpression of miR-148a,which had been verified to modulate DNMT1 expression, could reactivate the expression of E-cadherin. Knockdown of DNMT1 by DNMT1 siRNA could also increase the mRNA and protein levels of E-cadherin. Conclusion:The enforced expression of miR-148a may contribute to the reactivation of E-cadherin by suppression of DNMT1.