Targeting miR-9 in Glioma Stem Cell-Derived Extracellular Vesicles: A Novel Diagnostic and Therapeutic Biomarker

Abstract Background Glioblastoma, the lethal brain tumor with undesirable prognosis, still has no effective strategies in early diagnosis and treatment. Extracellular vesicles (EVs) isolated from cerebrospinal fluid (CSF) are a potential liquid biopsy source. This study was performed to assess the miRNA expression profiles in EVs from CSF and tissue of GBM patients to identify significantly upregulated miRNAs and investigate the underlying neoplastic mechanisms.Methods EVs were measured by TEM and NTA assays. Differentially regulated miRNAs were measured using RNA sequencing in GBM CSF EVs and in GBM tissues compared with controls. RT-qPCR was employed to analyze certain miRNA and gene expression. Luciferase report assay was used in investigate downstream gene target of miR-9. The proliferation ability was detected by EdU and CCK-8 experiment while cell migration was measured by transwell and wound healing assay.Results The expression level of miR-9 was significantly higher in GBM CSF EVs and tissues than controls (p = 0.038). The area under curve for CSF EV miR-9 was 0.080 (95% CI: 0.583–1.000, p = 0.033). The expression of miR-9 was significantly higher in GSCs and GSC-derived EVs compared with glioblastoma cells. GSC culture medium, which contained the GSC-derives EVs, could promote GBM growth and migration after administration to GBM cells. Moreover, inhibition of miR-9 in GSCs showed the reverse anti-tumor effects. MiR-9 could bind to the 3’UTR region of DACT3 and suppress its expression. The miR-9/DACT3 axis might attribute to GBM malignant phenotype.Conclusion MiR-9 in CSF EVs might act as a novel diagnostic biomarker for GBM and targeting miR-9 by GSC-derived EVs may be a specific and efficient strategy for GBM biotherapy.