Overexpression of miR-770 indicates a favorable prognosis and suppresses tumorigenesis by modulating PI3K-AKT pathway in glioma.

Abstract

Previous studies showed that miR-770 expression was deregulated in many tumors. However, the effect of miR-770 function on glioma remains as a mystery. The present study aimed to explore its expression, cellular function and clinic features in glioma. We analyzed RNA sequencing data to explore abnormally expressed miRNAs in glioma. Glioma tissue specimens and their matched normal tissues were collected to test miR-770 expression using quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) analysis. The correlation between miR-770 and the clinicopathological factors and the prognostic value of miR-770 was statistically analyzed. We then investigated alterations in a series of cancer-related phenotypes, including cell viability, apoptosis, colony formation and metastasis capacities. Western blot analysis was performed to examine the expression changes of EMT-related proteins and PI3K/Akt signaling pathway proteins. We identified a novel glioma-related miRNA miR-770, which was significantly down-regulated in human glioma tissues. The results of RT-PCR further showed that miR-770 expression was significantly down-regulated in both glioma tissues and cell lines. Furthermore, decreased miR-770 expression was significantly associated with advanced WHO grade, KPS score and shorter five-year overall survival. Then, functional assays indicated that overexpression of miR-770 suppressed proliferation, migration, invasion and EMT pathway, and induced the apoptosis of glioma cells in vitro. Moreover, we further illustrated that the up-regulation of miR-770 suppressed the PI3K-AKT signaling pathway. Our present findings firstly reported the roles and mechanisms associated with miR-770 in glioma progression, highlighting miR-770 as a potential therapeutic target for glioma patients.