miR-543 functions as a tumor suppressor in glioma in vitro and in vivo.

Gliomas are the most common primary central nervous system tumors and account for approximately 80% of malignant brain tumors. MicroRNAs (miRNAs) are a class of small non-coding, regulatory RNA molecules that mediate the expression levels of specific proteins. As a member of the miRNA family, miR-543 plays a tumor suppressive or an oncogenic role in different types of tumors. However, the expression and role of miR-543 in glioma remain unknown. In the present study, the expression level of miR-543 in glioma cell lines and tissues was investigated. A series of in vitro and in vivo experiments was then performed to elucidate the function of miR-543 in glioma. Moreover, proteomic profiling was applied in this study to determine the landscape of differentially expressed proteins associated with miR-543-mediated carcinogenesis in glioma. We found that the expression level of miR-543 was greatly downregulated in glioma cell lines and tissues. Furthermore, the expression level of miR-543 was negatively associated with high-grade glioma. Functional studies demonstrated that miR-543 in glioma cells induced apoptosis and inhibited growth, the cell cycle, migration and invasion. In addition, the in vivo study showed that miR-543 suppressed tumorigenicity of glioma cells. In the present study, a label-free quantitative proteomic approach was performed and 339 proteins were identified as dysregulated after miR-543 was overexpressed. Among these dysregulated proteins, 165 were upregulated and 174 were downregulated. Moreover, multiple pathways were significantly enriched and were probably involved in miR-543-mediated tumorigenesis, including RNA degradation and the inositol phosphate metabolism pathway. In conclusion, miR-543 may function as a tumor suppressor in glioma and may serve as a future therapeutic target in therapy for patients with glioma.