miR-134靶向EGFR对非小细胞肺癌增殖的影响

目的 探讨微小RNA-134（miR-134）对非小细胞肺癌（NSCLC）细胞增殖和凋亡的影响及可能的机制。方法 采用实时荧光定量PCR（QPCR）检测miR 134在NSCLC细胞株（A549、H252）和正常胚肺细胞株WI38中的表达情况；将A549和H252细胞分为3组，分别为空白对照组（不转染）、miR-NC组（转染不相关siRNA）和miR-134组（转染miR-134 mimics）。分别于转染后24、48、72、96h收集细胞，采用MTS法检测细胞的增殖情况；转染后96h用流式细胞仪检测细胞的凋亡情况；双荧光素酶报告基因实验检测miR-134与表皮生长因子受体（EGFR）3’UTR的结合情况，QPCR检测过表达miR-134的A549和H252细胞中EGFR的表达情况。结果 与WI38 细胞相比，miR-134在A549细胞中的表达下调85.91％，在H252细胞中下调78.13％（P＜0.05）。MTS检测显示，miR-134能显著降低A549和H252细胞的增殖能力，并呈时间依赖性。流式细胞仪检测显示，与空白对照组比较，miR-134组A549细胞的凋亡比例提高226.31％，H252细胞提高47.85％（P＜0.05）。双荧光素酶报告基因实验显示miR 134能与EGFR3’UTR结合，显著降低荧光值（P＜0.05）。QPCR检测显示，与空白对照组比较，转染miR-134 mimics 后，EGFR在A549细胞中的相对表达量下调57.0％，在H252中下调35.0％，差异均有统计学意义（P＜0.01）。结论 miR-134在NSCLC中低表达，能通过靶向EGFR抑制NSCLC细胞增殖，并诱导凋亡。

The influence of miR-134 on cell growth by targeting epidermal growth factor receptor in non-small cell lung cancer

Objective To investigate the effect of microRNA-134 (miR-134) on suppressing the proliferation of non-small cell lung cancer (NSCLC) and the possible mechanism.Methods The expression levels of miR-134 in NSCLC cell lines (A549,H252) and human embryo lung WI38 cells were detected by real-time quantitative-PCR (QPCR).A549 and H252 cell lines were divided into miR-NC group,miR-134 group and blank control group,which were transfected with control-siRNA,miR-134 mimics and none,respectively.The proliferation in the three groups of A549 and H252 cells was detected by MTS assays 24,48,72,96 h after transfect.Cell apoptosis were detected by flow cytometry after 96 h.A luciferase reporter assay was performed to confirm whether epidermal growth factor receptor (EGFR) was a direct target of miR-134.The expression level of EGFR was detected by QPCR.Results The level of miR-134 was found down-regulated 85.91％ in A549 cells and 78.13％ in H252 cells comparing with it in WI38 cells (P＜ 0.05).MTS assays showed that miR-134 suppressed A549 and H252 cells proliferation significantly in a time-depended manner.Flow cytometry showed that the apoptotic rate of A549 and H252 cells increased to 226.31％ and 47.85％ respectively compared with blank control group (P＜0.05).A dual-luciferase reporter assay confirmed that EGFR was a direct target of miR-134 by reducing the activity of luciferase (P＜0.05).QPCR showed that after the transfect of miR-134 mimics,the expression of EGFR down-regulated 57.0％ in A549 cells and 35.0％ in H252 cells compared with blank control group (P＜ 0.01).Conclusion miR-134 is down-regulated in NSCLC and inhibitcs cells growth,as well as induces cell apoptosis by targeting EGFR in NSCLC.