Objective:To explore the role of microRNA-650(miR-650) in the development and prognosis of gastric cancer and its clinical significance. Methods:Real-time quantitative reverse transcription-polymerase chain reaction was used to detect miR-650 expression levels in five gastric cancer cell lines and gastric cancer tissues. After the miR-650 mimic and inhibitor were transfected into gastric cancer cells,the cellular growth activity was estimated by CCK-8 kit; the apoptosis activity was tested by flow cytometry; the candidate targets of miR-650 were analysed using the LC-MS/MS-based techniques; western blot was used to test the expression levels of reglator of G-protein signaling 7(RGS7) which acted as a target of miR-650 in gastric cancer cells. Nude mouse xenograft model was used to explore the biological effect of miR-650 in gastric cancer cells and the curative effect of miR-650 inhibitor. Results: High levels of miR-650 have been detected in KATO III,NUGC4 and SGC-7901 gastric cancer cell lines,while NCI-N87 and MKN-45 gastric cancer cell lines only displayed low expression levels of miR-650. After transfection of LNA inhibitor,gastric cancer cell lines proliferation was significantly inhibited,while apoptosis was promoted. RGS7 was one of the functional downstream targets of miR-650,and the expression level of RGS7 was inversely correlated with the expression level of miR-650. MiR-650 inhibitor can suppress tumor growth. Conclusions: The up-regulation of miR-650 promotes proliferation,metastasis and inhibits apoptosis of gastric cancer cells,and possibly through suppressing the expression of RGS7.%目的:研究microRNA-650(miR-650)在胃癌组织中的表达及其与胃癌细胞增殖、凋亡及转移的关系.方法:采用逆转录聚合酶链式反应(reverse transcription-polymerase chain reaction,RT-PCR)检测miR 650在胃癌组织标本及胃癌细胞株中的表达量,胃癌细胞株转染miR-650模拟剂以及miR-650抑制剂-LNA寡核苷酸后采用CCK-8试剂盒检测细胞增殖情况,采用流式细胞仪检测细胞凋亡情况,采用LC-MS/MS系统定量分析筛选miR-650靶蛋白,采用蛋白质印迹检测miR-650靶蛋白RGS7的表达水平.采用裸鼠异种移植模型验证miR 650对胃癌细胞的生物学作用及其抑制剂的生物疗效.结果:胃癌细胞株KATO Ⅲ、NUGC4及SGC-7901高表达miR-650,而NCI-N87及MKN 45仅微量表达miR-650.在转染miR-650抑制剂-LNA寡核苷酸后胃癌细胞增殖水平显著下降,凋亡水平显著上升.G-蛋白信号调节因子7(regulator of G-protein signaling-7,RGS7)是miR-650下游靶点之一,靶蛋白RGS7表达水平与miR-650表达水平呈负相关,miR-650抑制剂可抑制肿瘤生长.结论:胃癌细胞株中miR 650的高表达可促进胃癌细胞增殖及转移并抑制其凋亡,机制可能是通过抑制靶蛋白RGS7的表达.
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