miR-218 is downregulated and directly targets SH3GL1 in childhood medulloblastoma.

An increasing number of studies have suggested that microRNAs (miRNAs) are aberrantly expressed in numerous types of tumors and that a deregulation in miRNA expression may lead to carcinogenesis. Although miR-218 has been demonstrated to be downregulated in several types of cancer, including medulloblastoma (MB), its involvement in MB is unclear. In the present study, the expression of miR-218 and SH3GL1 were assessed in four MB cell lines and normal cerebellum by qPCR. The ectopic expression of miR-218 induced by lentiviral transfection in MB cells on proliferation was evaluated by MTT assay, and cell migration and invasion were determined by transwell assays. Analysis of the target protein expression and related protein expression was determined by western blot analysis. The targeting of SH3GL1 by miR-218 was identified using a luciferase reporter assay. The results demonstrated that miR-218 was significantly downregulated in MB cell lines. MiR-218 significantly inhibited SH3GL1 mRNA and protein expression and reduced the luciferase activity of a SH3GL1 3' untranslated region-based reporter. Furthermore, overexpression of miR-218 induced by transfection with lentivirus significantly suppressed MB cell growth, migration and invasion in vitro. Small interfering RNA-mediated SH3GL1 downregulation partially phenocopied the effect of miR-218 overexpression in the MB cell lines. The results indicated that miR-218 was significantly downregulated in MB cancer cell lines. Furthermore, miR-218 functioned as a tumor suppressor by regulating SH3GL1 expression in MB cancer cells.