miR-25 promotes glioblastoma cell proliferation and invasion by directly targeting NEFL.

Glioblastoma multiforme (GBM) is the most malignant and common brain tumor; it is aggressive growth pattern means that GBM patients face a poor prognosis even when receiving the best available treatment modalities. In recent years, an increasing number of reports suggest that the discovery of microRNAs (miRNAs) might provide a novel therapeutic target for human cancers, including GBM. One miRNA in particular, microRNA-25 (miR-25), is overexpressed in several cancers, wherein accumulating evidence indicates that it functions as an oncogene. However, the function of miR-25 in GBM has not been totally elucidated. In this study, we demonstrated that miR-25 was significantly up-regulated in astrocytoma tissues and glioblastoma cell lines. In vitro studies further demonstrated that overexpressed miR-25 was able to promote, while its antisense oligos inhibited cell proliferation and invasion in U251 cells. Moreover, we identified neurofilament light polypeptide (NEFL) as a novel target molecule of miR-25. Also of note was the fact that NEFL was down-regulated with increased levels of miR-25 expression in human astrocytoma clinical specimens. In addition, via the mTOR signaling pathway, NEFL-siRNA could significantly attenuate the inhibitory effects of knockdown miR-25 on the proliferation and invasion of U251 cells. Overall, our results showed an important role for miR-25 in regulating NEFL expression in GBM, and suggest that miR-25 could be a potential target for GBM treatment.