Abstract:

Background and purpose: miR-22 has been reported to be down-regulated in gastric cancer, lung cancer, colorectal cancer, and breast cancer. However, its expression in glioma was still poorly known. This study aimed to explicit whether miR-22 suppresses cell proliferation by targeting MTDH, thus to reveal molecular mechanism that miR-22 functions as a tumor suppressor in glioma. Methods: Quantitative real-time polymerase chain reaction (qRTPCR) was conducted for detecting the expression of miR-22 in gliomas and normal brain tissues. MTDH 3’UTRluciferase vector was constructed and dual-luciferase reporter gene assay was employed to examine the effect of miR-22 on luciferase activity. U251 cells were transfected with miR-22 mimics, and MTDH siRNA as for postive control, then Western blot was performed to detect the expressions of MTDH protein. The proliferation ability of U251 cells was evaluated by MTT assay. Results: miR-22 was down-regulated in glioma tissues. Glioma patients with relatively high expression of miR-22 showed lower mortality compared with low expression of miR-22 by using Kaplan-Meier survival curves. We demonstrated miR-22 could bind to the 3’ untranslated region (UTR) of MTDH and inhibited the luciferase activity. Western blot showed that the expression of MTDH protein was inhibited by restored miR-22 or siR MTDH in U251 cells. Overexpression of miR-22 or siR MTDH inhibited the proliferation of U251 cells. Conclusion: miR-22 suppresses cell proliferation by targeting MTDH in glioma.

Key words: miR-22, Glioma, MTDH, Growth