miR-125b regulates the proliferation of glioblastoma stem cells by targeting E2F2.

microRNAs (miRNAs) play important role in regulating cancer stem cell self-renewal and differentiation, but the expression prolife of miRNAs in glioma stem cells (GSCs) has not been addressed. Here, we found that CD133 positive GSCs possess a unique miRNAs profile compared to CD133 negative glioblastoma cells. miR-125b, as one of neuronal miRNAs, is the most significantly down-regulated miRNAs and overexpression of miR-125b inhibits the proliferation of CD133 positive GSCs and reduces the expression of "stem" marker. Furthermore, two binding sites for miR-125b are identified in the 3'UTR of E2F2 and overexpression of miR-125b in CD133 positive GSCs represses the endogenous level of E2F2 protein. This study demonstrated that miR-125b plays important roles in regulating the proliferation of GSCs by directly targeting E2F2.