miR-518b is down-regulated, and involved in cell proliferation and invasion by targeting Rap1b in esophageal squamous cell carcinoma.

MicroRNAs (miRNAs) represent a class of small non-coding RNAs that regulate gene expression at the post-transcriptional levels. Recent studies show that miRNAs may function as oncogenes or tumor suppressor genes. In this study, we demonstrated that miR-518b was down-regulated in esophageal squamous cell carcinoma (ESCC) tissues and correlated with metastasis and survival. miR-518b suppressed the proliferation by inducing apoptosis and repressed the invasion in ESCC cells, but had no effect on the cell cycle. Furthermore, Rap1b was revealed to be directly regulated by miR-518b. These findings indicate that miR-518b may function as a tumor suppressor by targeting Rap1b in the development of ESCC and has important clinical and prognostic value.