miR‐21‐5p/SMAD7 axis promotes the progress of lung cancer

BACKGROUND: Lung cancer is one of the most common malignant tumors threatening human health. The aim of this study was to investigate the function of miR‐21‐5p in lung cancer progression. METHODS: We analyzed the expression levels of miR‐21‐5p in lung cancer tissues and cell lines. The qRT‐PCR and MTT assays were performed after transfection with miR‐21‐5p mimic, inhibitor and negative control into lung cancer cells. RESULTS: Luciferase reporter assays showed miR‐21‐5p directly target SMAD7. The miR‐21‐5p inhibitor significantly suppressed lung cancer cell proliferation, invasion and migration. We found that SMAD7 was upregulated in lung cancer tissue. In addition, we found that SMAD7 inhibited lung cancer cell proliferation and miR‐21‐5p mimic damaged the inhibitory effect of SMAD7. CONCLUSIONS: miRNA‐21‐5p may promote cell proliferation, migration and invasion by spoiling SMAD7 expression in lung cancer cells.