The Study On MiR-27a Expression And Malignant Phenotype In Glioma In Vitro

Background:Glioma is the most common primary tumor in the central nervous system. Owing to the invasive growth and rapid cell proliferation, though the malignant glioma is to be cured by the currently available therapeutic approaches, such as surgical resection, postoperative radiotherapy, chemotherapy, immunotherapy, comprehensive therapy, the prognosis is poor with a median survival of12months. High grade glioma is highly heterogeneous, and it is believed that loss control of many signaling pathways induced by genetic mutations or epigenetic changes plays an important role. Wnt/beta-catenin signaling pathways and its upstream miRNA had been focused on.Wnt/beta-catenin signaling has been proved to be associated with various disease pathologies, especially in glioma-genesis. The pathway activates downstream targets and thereby regulates many biological processes through a complex of beta-catenin and T cell factor/lymphoid-enhancer factor1(TCF/LEF-1) family. Wnt stabilizes cytosolic beta-catenin, which then binds to TCF/LEF-1in the nucleus and recruits transcription factors Brg1and CREB-binding protein to initiate Wnt-targeted gene expression It was showed that SFRP1, as an inhibitor of Wnt/beta-catenin signaling, can induce apoptosis. We searched several microRNA target prediction database, such as TARGETSCAN and MIRANDA and several different miRNAs were predicted to have SFRP1as putative target, including miR-27a. We study miR-27a inhibitor suppress proliferation, apoptosis, cycle and invasion/migration and its mechanism.MethodsMiR-27a expression was examined in8malignant glioma cell lines and9freshly resected glioma samples by qRT-PCR. It was found that these microRNAs were upregulated in gliomas. We transfected miR-27a inhibitor to the human glioma cell lines LN229and U251. QRT-PCR was conducted to detect the expression of miR-27a in transfected cells. The cell proliferation rate was determined by MTS assay and cell cycle kinetics was detected by Propidium staining assay. The cell apoptosis was examined by Annexin V assay and invasive/migration ability was evaluated by Transwell assay.ResultsThe results showed that the expression of miR-27a in glioma cells and samples were significantly upregulated. The expression of miR-27a in the cells transfected with miR-27a inhibitor was significantly downregulated. The cell proliferation activity and invasive ability were reduced, cells were arrested in G0/G1phase, and apoptosis was induced in cell transfected with miR-27a inhibitor as compared to those of the cells transfected with control cells. The express of PCNA、Bcl2、CyclinD1、MMP-9decreased after miR-27a inhibitor treated. These findings showed that miR-27a is an oncomiR which can promote the growth of glioma.ConclusionThe results demonstrate that miR-27a expression increased significantly. Transfection of miR-27a inhibitor into the glioma cells is able to inhibit the glioma cell proliferation activity, invasive ability, arrest the cells in G0/G1phase, and induce cell apoptosis. Thus, miR-27a is identified as an oncomiR which implicate that they can be candidate targets for gene therapy of glioma. Our study on the expression and the potential mechanism of miR-27a in glioma-genesis can provide the molecular pathologic mechanism and a new class of targeted therapeutic strategy for human gliomas.