Glioblastoma cell-derived extracellular vesicle miR-27a-3p facilitates M2 macrophage polarization

Abstract Background: M2 macrophage polarization has been found to be correlated with malignancy of glioblastoma. In this study, we investigated the potential role of microRNA (miRNA) derived from extracellular vesicles of glioblastoma (glioblastoma-EVs) in M2 macrophage polarization.Methods: After isolation of human glioblastoma-EVs, transmission electron microscopy (TEM) and Nano-particle tracking analysis (NTA) were performed to identify the EVs. Besides, the proliferation, migration and invasion of glioma cells were analyzed by CCK8 and Transwell assays, respectively. The target genes of miR-27a-3p were predicted through bioinformatics analysis and verified by dual-luciferase reporter gene assay. ChIP assay was applied to detect the binding of enhancer of zeste homologue 1 (EZH1) to lysine-specific demethylase 3A (KDM3A) promoter region and the interaction between KDM3A and connective tissue growth factor (CTGF). Glioblastoma mouse models were established followed by the implement of hematoxylin-eosin (HE) and ELISA staining on pathological changes of mouse brain tissues.Results: Human glioblastoma-EVs were successfully isolated. The high expression of miR-27a-3p was found in glioblastoma tissues as well as glioblastoma-EVs, which could induce M2 polarization, thus promoting glioblastoma cell proliferation, migration and invasion. It was also shown that miR-27a-3p targeted EZH1 and promoted KDM3A expression to elevate the expression of CTGF. Glioblastoma-EVs delivered miR-27a-3p to promote the KDM3A-upregulated CTGF by downregulating EZH1, thereby promoting M2 macrophage polarization and development of glioblastoma in vivo.Conclusion: These findings highlight that EV miR-27a-3p may promote M2 macrophage polarization, which is associated with the progression of tumors.