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

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 ß-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/ß-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 ß-catenin were negatively associated with miR-449b-5p levels in glioblastoma cells. MiR-449b-5p inhibited Wnt/ß-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/ß-catenin signaling by directly targeting WNT2B.

MicroRNA-370-3p inhibits human vascular smooth muscle cell proliferation via targeting KDR/AKT signaling pathway in cerebral aneurysm.

OBJECTIVE: Cerebral aneurysm is a common vascular disease with high morbidity and mortality. Vascular smooth muscle deletion or dysplasia is an important reason for the development of cerebral aneurysm. MiRNAs participate in a variety of biological functions through inhibiting target gene translation. The aim of the present study was to evaluate the role of miRNAs in the regulation of vascular smooth muscle cell proliferation. MATERIALS AND METHODS: MiRNA and mRNA expressions were tested by Real-time PCR. Cell cycle was detected by flow cytometry. Cell viability was evaluated by MTT assay. HUASMC cell proliferation was determined by BrdU assay. Protein expressions were determined using Western blot. MiRNA target gene was confirmed by luciferase assay. RESULTS: MiR-370-3p expression was increased in cerebral aneurysm tissues. Ectopic expression of miR-370-3p suppressed proliferation of vascular smooth muscle cells and blocked cell cycle. Numerous cell proliferation and apoptosis-related factors were down-regulated by miR-370-3p. Results of target prediction database and dual-luciferase assay revealed that KDR is a direct target of miR-370-3p. Importantly, FOXO1 activity and AKT and FOXO1 phosphorylation were inhibited by miR-370-3p. We suggest that miR-370-3p directly targets KDR, resulting in the activation of AKT signaling pathway. CONCLUSIONS: MiR-370-3p was involved in the development of cerebral aneurysm by targeting KDR and blocking AKT/FOXO1 signaling pathway. The results provide theoretical basis for further investigation of potential clinical prevention and treatment of cerebral aneurysm.