MicroRNA-494 promotes tumor growth by targeting PTEN in non-small cell lung cancer

Lung cancer is the most common cause of cancer-related deaths worldwide. Non-small cell lung cancer (NSCLC) accounts for 80% of all cases of lung cancer patients. MicroRNA-494 (miR-494) has been reported to play important roles in tumorigenesis of various human cancers. However, the roles and underlying molecular mechanism of miR-494 in NSCLC have not been totally elucidated. Therefore, the purpose of this study was to investigate the possible regulatory mechanisms of miR-494 in NSCLC. Herein, we demonstrated that miR-494 as oncogene MicroRNA in NSCLC progression was significantly up-regulated in NSCLC tissue samples and cell lines compared with normal lung tissues and cell line. The further research shows that down-regulation of miR-494 significantly delayed cell proliferation, increased apoptosis and pro-apoptotic related protein expression in NSCLC cell lines. Moreover, PTEN (phosphatase and tensin homolog), a unique tumor suppressor gene, was confirmed as a direct target of miR-494. We also found that the messenger RNA (mRNA) expression was decreased in NSCLC tissues and was inversely correlated with miR-494. Further study showed that knockdown of PTEN by siRNA could reverse the inhibitory effect of miR-494 inhibitor on proliferation and apoptosis of NSCLC cells. Thus, miR-494 may be a potential prognostic marker and of treatment relevance for NSCLC progression intervention.