MicroRNA-421 enhances cell migration and invasion by down-regulating TIMP-2 in glioblastoma

MicroRNA-421 (miR-421) has been identified to play critical roles in various cancers, but the roles of miR-421 in migration and invasion of glioblastoma (GBM) remains unknown. The aim of this study was to investigate biological functions and its molecular mechanisms of miR-421 in GBM cells. Real-time PCR was applied to assess the expression of miR-421. Migration and invasion of GBM cells were analyzed by transwell migration and invasion assays. Luciferase reporter assay was employed to detect cell target genes of miR-421, while and expression of TIMP-2 were verified by western blot analysis. The results showed that miR-421 expression levels were increased in GBM tissues and GBM cell lines compared to normal brain tissues. Then, transwell migration and transwell invasion assays showed that transfection of miR-421 inhibitor significantly inhibited migration and invasion capacity of U87 and U251 cells, while the miR-421 inhibition-induced migratory and invasive abilities of the GBM cell lines were abolished by TIMP-2 downregulation. Further studies indicated that miR-421 negatively regulates TIMP-2 expression via direct binding to putative binding site in the TIMP-2 3' untranslated region. Therefore, we concluded that miR-421 could enhance tumor migration and invasion in GBM by targeting TIMP-2 and may be identified as a potential therapeutic target of GBM.