miR-615-3p promotes proliferation and migration and inhibits apoptosis through its potential target CELF2 in gastric cancer.

Gastric cancer incidence is relatively higher in China than that in developed countries; however, molecular mechanisms considering the initiation and progression of gastric cancer are still unclear. For decades, numerous microRNAs have been found to regulate a wide range of biological functions in gastric cancer. However, the oncogenic function of miR-615-3p in gastric cancer has not been reported to date. With the help of gene and microRNA chips in 10 patients, we were able to screen differential expressed genes and microRNAs compared with normal gastric tissues. After that, online bioinformatics analysis tools were used to predict microRNAs' potential targets. As a result, miR-615-3p and its potential target, CELF2, were selected for further experiments. QRT-PCR and western blot results indicated the aberrant high expression of miR-615-3p and low expression of CELF2 in gastric cancer both in vivo and in vitro. Moreover, miR-615-3p expression correlated to T and M stage. Up regulation of miR-615-3p inhibited the apoptosis, promoted proliferation and migration and led to the down-regulation of CELF2. Meanwhile, down-regulation of miR-615-3p resulted in anti-tumor effects. Immunochemistry staining of CELF2 showed its association with T, N and M stage. In addition, overexpression of CELF2 could reverse miR-615-3p's oncogenic functions stated before. These findings indicate that miR-615-3p promotes gastric cancer proliferation and migration by suppressing CELF2 expression for the first time, providing clues for future clinical practices.