JPBS

Background: Brain glioma is a common primary intracranial tumor with unfavorable prognosis. MicroRNA-21 (miR-21) is a small RNA molecule involved in post-transcriptional modulation and is closely associated with cell growth and differentiation. Recent studies have shown that miR-21 expression affects tumor proliferation and growth via the PI3K/AKT signaling pathway. This study investigated the expression of miR-21 in glioma and its effects on the PI3K/AKT pathway and cell proliferation. Methods: A total of 35 brain glioma patients were recruited from March 2013 to November 2014 at our hospital. In situ hybridization (ISH) and RT-PCR were used to detect the expression of miR-21 in both tumors and adjacent brain tissues. Human brain U251 glioma cells were transfected with anti-miR-21 to suppress miR-21 expression, followed by immunofluorescent assay of PI3K and AKT expression profiles. Flow cytometry was employed to detect the change between different stages of the cell cycle. Results: ISH results showed significantly elevated miR-21 expression level in glioma tissues compared to normal brain tissues. RT-PCR analysis revealed a 3.5-fold increase in miR-21 in the anti-miR-21 transfected glioma cells compared to untransfected cells. After silencing miR-21 in U251 cells, immunofluorescent assay indicated that the expression of PI3K and AKT significantly decreased. Flow cytometry revealed an increased number of cells at G0/G1 phase in anti-miR-21 transfected U251 cells, suggesting suppressed cell division ability. Conclusion: MiR-21 expression was found to be increased in brain glioma tissues, accompanied with over-activation of PI3K/AKT signaling and proliferation of glioma cells.

Brain glioma; MicroRNA-21; PI3K/AKT signal pathway; Cell proliferation