MiR-449b-5p inhibits human glioblastoma cell proliferation by inactivating WNT2B/Wnt/β-catenin signaling pathway

W.-Z. Hou, X.-L. Chen, L.-S. Qin, Z.-J. Xu, G.-M. Liao, D. Chen, L.-J. Hu, Z.-M. Mao, J.-S Huang, Q. Yuan, C. Liao, Q.-M. Yao

Department of Neurosurgery, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan City People’s Hospital, Guangdong Province, China. qmyao005@sohu.com

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• Oncology

OBJECTIVE: As the most common primary brain cancer in adults, glioblastoma shows an extremely poor prognosis. Glioblastoma-associated deaths account for approximately 3%-4% of all malignancy-associated deaths. Numerous microRNAs (miRNAs) play important roles in the occurrence and progression of solid tumors. Herein, identifying functional miRNAs and the central molecular mechanisms would provide novel proofs for the development of targeted cancer therapies. In this study, we described the role of miR-449b-5p in restraining ontogenesis and progression of glioblastoma.

PATIENTS AND METHODS: Human glioblastoma tissues were provided by our hospital. Human U251 glioblastoma cells were infected with lentivirus induced miR-449b-5p mimics or miR-449b-5p siRNA. Real-time qPCR was carried out to determine miRNA expression. Tumor spheres formation, MTT assay, and BrdU cell proliferation assay were used to evaluate the growth ability of U251 cells. Western blot assay was performed to measure protein expression. ChIP was used to detect the capacity of β-catenin to recruit its downstream genes. Dual-Luciferase assay was conducted to detect the ability of miR-449b-5p to regulate the 3’UTR (untranslated regions) of WNT2B. TOP/FOP ratio was used to evaluate the activity of Wnt/β-catenin signaling pathway.

RESULTS: Down-regulation of miR-449b-5p expression was found in both human glioblastoma tissues and cell lines, which was negatively associated with the clinical stages. Up-regulation of miR-449b-5p inhibited tumor spheres formation, cell viability and proliferation ability of glioblastoma cells. The expression levels of WNT2B and nuclear β-catenin were negatively associated with miR-449b-5p levels in glioblastoma cells. MiR-449b-5p inhibited Wnt/β-catenin signaling by targeting WNT2B.

CONCLUSIONS: MiR-449b-5p acts as a tumor suppressor and retards the oncogenesis of glioblastoma, which is achieved via inactivation of Wnt/β-catenin signaling by directly targeting WNT2B.

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