MicroRNA-21 regulates non-small cell lung cancer cell proliferation by affecting cell apoptosis via COX-19.

AIMS This study is to investigate the regulatory effect of microRNA-21 (miR-21) on bone metastasis of non-small cell lung cancer (NSCLC). METHODS In this study, 18 patients were diagnosed with vertebral column metastasis of NSCLC. MiR-21 or small interfering RNAs were transfected into H2170 cells using Lipofectamine 2000. Real-time PCR was performed to detect miR-21 expression. Western blotting was used to measure the expression of COX-19 protein. Enzymatic activity tests were performed to measure the activity of cytochrome C oxidase. Flow cytometry was used to monitor changes in cell apoptotic rate. MTT assay was used to determine the capability of cell proliferation. RESULTS Bone metastasis of NSCLC enhanced the levels of miR-21 in NSCLC patients. Proliferation capability of cells with high expression of miR-21 was greater than that of cells with the inhibition of miR-21 expression. High expression of miR-21 promoted cell proliferation by inhibiting cell apoptosis. COX-19 was a key factor in the inhibition of apoptosis by miR-21. Inhibition of COX-19 expression reduced cell proliferation by enhancing cell apoptosis. CONCLUSIONS This study demonstrates that inhibition of miRNA-21 suppresses NSCLC cell proliferation by promoting cell apoptosis via the decrease of COX-19 expression.