Abstract:

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 inhibites cells growth，as well as induces cell apoptosis by targeting EGFR in NSCLC.