MicroRNA-34a Suppresses Cell Proliferation and Induces Apoptosis in U87 Glioma Stem Cells

Tumor stem cells (TSCs) have been identified in many malignant tumors and are unique in their self-renewal, multi-differentiation and tumor growth maintenance capabilities. Micro-RNAs (miRNAs) are small endogenous, non-coding RNAs that predominately modulate target gene expression at the post-transcriptional level. Accumulating evidence suggests that some miRNAs have an essential role in TSC proliferation, growth, apoptosis, and differentiation. In particular, miR-34a has been found to inhibit proliferation and induce apoptosis in stem cells. The insensitivity of glioma to standard therapies combined with the hypothesis that glioma stem cells (GSCs) are responsible for this chemorefractory nature suggests that investigations exploring the function and mechanism of miR-34a in GSCs would be of value. In our study, we found that miR-34a is down-regulated in CD133-positive U87 cells. Furthermore, miR-34a could significantly suppress cell proliferation and induce apoptosis in GSCs. These findings suggest that miR-34a acts as a tumor suppressor in U87 GSCs. Therefore, this observation highlights a new potential therapeutic agent for GSC-based glioma treatment.