Evaluation of microRNA-203 in bone metastasis of patients with non-small cell lung cancer through TGF-β/SMAD2 expression.

This study investigated the regulatory effect of microRNA-203 on bone metastasis of non-small cell lung cancer (NSCLC). Quantitative real-time PCR was used to examine microRNA-203 in tissue specimens of bone metastasis of patients with NSCLC. In bone metastasis of patients with NSCLC, microRNA-203 expression was decreased, compared with control group. We also surveyed overall survival (OS) and disease-free survival (DFS), microRNA-203 high expression in bone metastasis of patients with NSCLC was higher than in those with microRNA-203 low expression. Furthermore, we overexpressed microRNA-203 with microRNA-203 mimics and observed the effects of microRNA-203 overexpression on cell proliferation, apoptosis and migration of NSCLC cells. We found that microRNA-203 overexpression reduced cell proliferation and migration, induced apoptosis, Bax, caspase-3 and p53 protein expressions, repressed p-SMAD2 and TGF-β1 protein expression of NSCLC cells. Knockdown of TGF-β1 by LY364947 (10 nM) reduced cell proliferation and migration, induced apoptosis, expression of Bax, caspase-3 and p53 protein and suppressed TGF-β1 and p-SMAD2 protein expression of NSCLC cells transfected with miR-124 mimics. In conclusion, our data suggest that microRNA-203/TGF-β/SMAD2 expression plays an important role as a tumor suppressor gene in bone metastasis of patients with NSCLC, and may reveal novel perspectives for clinical treatments against bone metastasis of patients with NSCLC.