MicroRNA-155对人肺癌95D细胞生长的影响

摘要

Background and objective Recent studies suggest that miR-155 is involved in lung tumorgenesis, whereas the precise mechanism has not yet been characterized. The aim of this study is to investigate the effects of over-expression of miR-155 on the growth of human lung cancer 95D cells in vitro and its possible mechanism, and thus to provide experimental evidence for further researching on the role of miR-155 in the pathogenesis and development of lung cancer. Methods miR-155 mimics control and miR-155 mimics were tranfected into human lung cancer 95D cells by FuGENE* HD Transfection Reagent respectively in vitro. The relative expression level of miR-155 in 95D cells was determined using specific probe of real-time PCR after transfection. The proliferation of 95D cells was detected by MTT assay. The cell cycle was analyzed by flow cytometry. The expression of SOS 1 protein was measured by Western blot. Results Compared with control groups, the expression level of miR-155 was significantly increased in miR-155 mimics transfected group (P<0.05). The proliferation of miR-155-transfected 95D cells was significantly inhibited (P<0.05). The percentage of G0/G, phase cells was increased significantly in miR-155-transfected 95D cells, while the percentage of S phase was remarkably reduced (P<0.05). Furthermore, the expression of SOS1 in miR-155-transfected 95D cells was significantly down-regulated (P<0.05). Conclusion miR-155 could significantly inhibit the growth of human lung cancer 95D cells in vitro, which might be closely related to miR-155 induced G0/ G, phase arrest.%背景与目的近年来的研究发现miRNAs(microRNAs)家族成员miR-155与肺癌的发生相关,然而具体机制不明.本研究拟探讨上调miR-155表达对人肺癌95D细胞体外生长的影响及其可能的作用机制,为后续深入研究miR-155在肺癌发生、发展中的作用提供新的实验依据.方法人肺癌95D细胞分为空白对照组、miR-155阴性对照组和miR-155转染组,分别作加入转染试剂、转染miR-155阴性对照和转染miR-155处理.Real-time PCR特异性探针法检测转染后95D细胞中miR-155的表达水平；应用MTT法检测miR-155对95D细胞增殖的抑制作用；流式细胞术检测95D细胞周期的分布；Westernblot检测95D细胞SOS1蛋白的表达变化.结果Real-time PCR结果显示,与对照组相比,转染组95D细胞miR-155的表达水平明显增加(P＜0.05)；镜下可见转染miR-155的95D细胞生长减缓,形态发生改变；MTT结果表明miR-155转染后,95D细胞增殖受到抑制,转染组和对照组存在明显差异(P＜0.05)；流式细胞术分析显示,与对照组相比,转染miR-155的95D细胞周期发生改变,G0/G1期细胞明显增多,而S期则明显减少(P＜0.05):Western blot结果显示转染组95D细胞SOSI蛋白的表达明显降低(P＜0.05).结论miR-155能明显抑制人肺癌95D细胞的体外生长,这可能与miR-155下凋SOS1表达及诱导95D细胞G0/G1期阻滞相关.