miR-137 inhibits the proliferation of human non-small cell lung cancer cells by targeting SRC3.

Non-small cell lung cancer (NSCLC) is the most common type of lung cancer. The results of the present study demonstrate that high expression of microRNA (miR)-137 and low expression of steroid receptor coactivator-3 (SRC3) had a significant negative correlation in 40 NSCLC tissue samples. In addition, cell colony formation and proliferation was significantly reduced in miR-137-transfected A549 and NCI-H838 cells compared with scramble-transfected NSCLC cell lines. miR-137 was identified to induce G1/S cell cycle arrest and dysregulate the mRNA expression of cell cycle-associated proteins (proliferating cell nuclear antigen, cyclin E, cyclin A1, cyclin A2 and p21) in NSCLC cells. Notably, miR-137 could significantly suppress SRC3 3' untranslated region (UTR) luciferase-reporter activity, an effect that was not detectable when the putative 3'-UTR target-site was mutated, further clarifying the molecular mechanisms underlying the role of miR-137 in NSCLC. In conclusion, the results of the present study suggest that miR-137 suppresses NSCLC cell proliferation by partially targeting SRC3.