miRNA-186靶向Twist-1促胃癌侵袭、迁移的机制研究

目的检测miRNA-186在胃癌中的表达情况，观察miRNA-186表达改变对人胃癌细胞株侵袭、迁移能力的影响并分析可能的分子机制。方法RT-PCR法检测40例胃癌患者胃癌及配对的正常胃黏膜组织中miRNA-186的表达水平，同时检测miRNA-186在胃癌细胞株和正常胃黏膜上皮细胞中的表达水平。在胃癌细胞中分别转染miRNA-186模拟物（mimic）、抑制物（inhibitor）以上调、下调miRNA-186的表达，应用Transwell试验观察其对胃癌细胞侵袭、迁移能力的影响。应用生物信息学软件预测miRNA-186可能的靶基因，并经双荧光素酶试验及Westernblot试验验证靶基因，分析其促转移的分子机制。结果胃癌组织相较于正常胃黏膜组织、胃癌细胞株相较于正常胃黏膜上皮细胞株的miRNA-186表达水平均降低（均P＜0.05）。在胃癌细胞中，分别上调、下调miRNA-186的表达水平，能够抑制、促进胃癌细胞的侵袭、迁移能力。miRNA-186与Twist-1之间存在反向调控的关系，Twist-1是miRNA-186的靶基因。同时发现，下调miRNA-186的表达时，Twist-1和N-cadherin表达上调，E-cadherin表达下调，而当上调miRNA-186的表达时，Twist-1和N-cadherin表达下调，E-cadherin表达上调。结论在胃癌组织中miRNA-186的表达水平降低，可能通过靶向调控Twist-1的表达，改变E-cadherin和N-cadherin的表达水平，导致胃癌细胞上皮间质转化，进而促进胃癌细胞的侵袭、迁移。

miRNA-186 promotes invasion and migration of gastric cancer cells by targeting Twist-1

Objective To investigate the effects of miRNA-186 on invasion and migration of gastric cancer cells and its possible mechanism. Methods The expression of miRNA-186 in gastric cancer tissue and gastric cancer cell line was detected by qPCR method. A mimic or an inhibitor of miRNA-186 was transfected into the gastric cancer MKN-28 and 7901 cells, respectively and the migration and invasion capacity of transfected cells were investigated using Transwell assays. The target genes of miRNA-186 and corresponding molecules were predicted according to miRBase Targets, TargetScan Release 5.0 and PicTar databases, and indentified by dual luciferase reporter assay and Western-blot assay. Results Among 40 gastric cancer tissue samples and 6 gastric cancer cell lines, the miRNA-186 expression levels were significant decreased compared with normal gastric tissue or cell lines. Transwell assay results indicated that inhibitor the expression of miRNA-186 in 7901 cells by transfecting the miRNA-186 inhibitors, the migration and invasion capacity of the cells was significantly increased, but that in MKN-28 cells transfected with miRNA-186 mimics was significantly decreases. Target gene prediction database and dual luciferase reporter assay indentified that Twist-1 was the target gene of miRNA-186. Western blot showed that the Twist-1 expression level was significantly increased, the cancer epithelial-mesenchymal transformation (EMT) markers E-cadherin was decreased, and the N-cadherin was increased when the expression of miRNA-186 was decreased in transfected 7901 cells. The contrast results were observed when the expression of miRNA-186 was increase in transfected MKN-28 cells. Conclusion MiRNA-186 is down-regulated in gastric cancer tissues, it may promote migration and invasion of gastric cancer cells by targeting Twist-1 and inducing EMT.