The effect of miR-203 on the migration and invasion of lung adenocarcinoma cells via targeting Bmi-1

XU Lei; JIANG Feng; YANG Xin; DA Liangshan; QIAN Yichun; WANG Jie; YIN Rong; XU Lin

Abstract：Objective To investigate the expression of miR-203 in lung adenocarcinoma and analyze the relationship between miR-203 and migration and invasion of lung adenocarcinoma cells. The involved molecular mechanisms are also initially explored. Methods miR-203 was detected in lung tissues of 40 patients with lung adenocarcinoma by real time PCR. The expression of miR-203 was detected in lung adenocarcinoma cell lines H1650, A549, H1975, SPC-A-1 by real time PCR. The potential target gene of miR-203 was predicted by online bioinformatic softwares. Pre-miR-203 mimics, Bmi-1 gene and Bmi-1 siRNA were transfected into H1975 cell line by lipofectamine 2000. The Bmi-1 protein level was analyzed by Western blotting. The predicted miR-203 binding site in Bmi-1 3’-untranslated region( UTR) was validated by dual-luciferase reporter gene assay. The migration ability of H1975 cells was determined by Transwell assay. Results The relative expression of miR-203 in lung adenocarcinoma tissues was 0?065 ± 0?013. The expression level of miR-203 in the lymph node metastasis group was lower than those in the non-metastasis group. The relative expression of miR-203 in H1650, A549, H1975 and SPC-A-1 cell lines were 0?280 ± 0?102, 0?308 ± 0?168, 0?167 ± 0?073 and 0?287 ± 0?096, respectively. Bmi-1 was a potential target gene of miR-203 predicted by miRanda and TargetScan. The Bmi-1 protein level was remark-ably decreased in the pre-miR-203 mimics group. Dual-luciferase reporter gene assay validated the predicted miR-203 binding site of Bmi-1 3’ UTR. Overexpression of miR-203 significantly inhibited the migration and invasion of H1975 cells, whereas the cell migration and invasion ability could be restored by overexpression of Bmi-1. Conclusion miR-203 can suppress the migration of lung adenocar-cinoma cell line H1975 via down-regulating Bmi-1 expression. miR-203 might be a potential tumor metastasis suppressor miRNA.