Down-regulation of miR-4500 promoted non-small cell lung cancer growth.

BACKGROUND Lung cancer is the lead cause of cancer-related mortality around the world. Non-small cell lung cancer (NSCLC) accounts for nearly 85% of all case of lung cancer. Accumulating evidence revealed the importance of miRNAs in the pathogenesis of NSCLC. Whether miR-4500 promotes NSCLC or not is still unknown. The potential targeted genes needed to be investigated. METHODS The level of miR-4500 was measured by qRT-PCR. The role of miR-4500 in patient survival was revealed by the Kaplan-Meier plot of overall survival of NSCLC patients. miR-4500 was up or down regulated by miRNAs mimics or ASO transfection. Cell proliferation and apoptosis were assayed by the MTT assay and FACS analysis separately. Targeted genes were predicted by a bioinformatic algorithm and confirmed by the Dual Luciferase reporter assay system. RESULTS NSCLC cell lines and tissues showed lower level of miR-4500. High miR-4500 expression was correlated with high patient survival rate. MiR-4500 overexpression inhibited NSCLC proliferation and induced apoptosis and vice versa. LIN28B and NRAS were targeted by miR-4500. CONCLUSIONS Low expression of miR-4500 in NSCLC promoted tumor growth by targeting LIN28B and NRAS. MiR-4500 may be a prognosis predictor and potential target for NSCLC therapy.