MicroRNA-124 suppresses Slug-mediated lung cancer metastasis

OBJECTIVE: Non-small cell lung cancer (NSCLC) is the most common type of lung cancer but its carcinogenesis remains not completely elucidated. Dysregulation of microRNAs (miRNAs) is involved in the development of various cancers, including NSCLC, whereas a role of miR-124 in the pathogenesis of NSCLC has not been reported. Here we addressed these questions. PATIENTS AND METHODS: We examined the levels of Slug and miR-124 in NSCLC tissue, compared to the adjacent non-tumor tissue. We also examined the relationship between miR-124 and Slug. The levels of miR-124 were then modified in NSCLC cells, and then the effects on cell invasion were evaluated. RESULTS: We detected significantly higher levels of Slug and significantly lower levels of miR-124 in NSCLC tissue, compared to the adjacent non-tumor tissue, and the values of miR-124 and Slug were inversely correlated. Moreover, the low miR-124 levels in NSCLC specimens were associated with poor survival of the patients. In vitro, overexpression of miR-124 significantly inhibited cell invasion, while depletion of miR-124 increased cell invasion in NSCLC cells. The effects of miR-124 on cell growth appeared to result from its regulation of Slug. CONCLUSIONS: Our study highlights miR-124 as a previously unrecognized factor that controls NSCLC invasiveness, and the findings here may be important for developing the innovative therapeutic treatment for NSCLC.