MicroRNA-367 directly targets PIK3R3 to inhibit proliferation and invasion of oral carcinoma cells

Recently, microRNA-367 (miR-367) has been reported to function as both tumor suppressor and oncogene in several cancer types, including gastric cancer, hepatocellular cancer and lung cancer. However, the biological function of miR-367 and its precise mechanisms in oral squamous cell carcinoma (OSCC) have not been well clarified. The aim of the present study was to study the roles of miR-367/PIK3R3 axis in OSCC. The levels of PIK3R3 and miR-367 were detected by quantitative PCR assay in OSCC tissues and cell lines. Moreover, the biological roles of miR-367 and PIK3R3 in OSCC cells were assessed by cell proliferation and invasion. The mRNA and protein levels of PIK3R3 were determined by using quantitative PCR and Western blotting assays. Luciferase assays were used to confirm that PIK3R3 was one target of miR-367. In the present study, the miR-367 level was dramatically reduced in OSCC tissues and cell lines, and the PIK3R3 expression was significantly enhanced. What’s more, the PIK3R3 expression was negatively related to the miR-367 level in OSCC tissues. Furthermore, up-regulation of miR-367 obviously restrained OSCC cells proliferation and invasion. We confirmed that miR-367 could directly target PIK3R3 by luciferase reporter assay. Besides, knockdown of PIK3R3 also could markedly inhibit the proliferation and invasion of OSCC cells. Finally, overexpression of miR-367 in OSCC cells partially reversed the promoted effects of PIK3R3 up-regulation. Overexpression of miR-367 restrained OSCC cells proliferation and invasion via regulation of PIK3R3.