MiR-140-5p suppresses retinoblastoma cell growth via inhibiting c-Met/AKT/mTOR pathway.

MiR-140-5p is low expression and acts as a tumor suppressor in various types of human cancers. However, the potential role of miR-140-5p in retinoblastoma (RB) remains unknown. In the present study, we performed the miRNA microarray analysis to investigate whether miRNAs expression are associated with RB tumorigenesis in RB tissues. We found that a large set of miRNAs were ectopic expressions and miR-140-5p is most significantly down-regulated in human RB tissues compared with normal retinas. In addition, low miR-140-5p expression is associated with clinicopathological features (differentiation, invasion, T classification, N classification, cTNM stage, and largest tumor base) and poor survival in RB patients. Furthermore, our results showed that overexpression of miR-140-5p suppresses proliferation and induces apoptosis and cell cycle arrest in RB cell. Meanwhile, we confirmed that c-Met is the functional target of miR-140-5p in RB cell, and miR-140-5p expression is negatively correlated with c-Met in RB tissues. We also found that inhibition of c-Met also suppresses proliferation and induces apoptosis and cell cycle arrest in RB cell. Interestingly, c-Met can rescue the suppressive effects of miR-140-5p on RB cell growth and cell cycle arrest. More importantly, our findings indicated that miR-140-5p may inhibit cell growth via blocking c-Met/AKT/mTOR signaling pathway. Collectively, these results suggested that miR-140-5p might be a potential biomarker and target in the diagnosis and treatment of RB.