Exosomes derived from hypoxia-exposed glioma cells promotes glioma stem cell migration by JAK/STAT3 signalling pathway

Abstract

Objective To investigate the effect of exosomes secreted by hypoxia-exposed glioma cells on the migration ability of glioma stem cells in vitro. Methods Exosomes were isolated from glioma cells with hypoxia exposure or in normoxic culture by ultracentrifugation and identified by transmission electron microscopy, dynamic light scattering and Western blotting. The exosomes were labeled with DIO to allow observation of their intake by glioma stem cells under fluorescent microscope. The glioma stem cells were co-cultured with the exosomes or PBS for 24, 48, or 72 h, and CCK-8 assay and Transwell assay were performed to assess the changes in the proliferation and migration ability of the cells. The changes in the phosphorylation levels of the proteins in the JAK/STAT3 pathway were detected using Western blotting. Results Fluorescence signals were detected in the glioma stem cells co-cultured with the DIO-labeled exosomes. The results of CCK-8 assay showed that the glioma stem cells showed no significant changes in their proliferative activity after co-culture with the exosomes from the glioma cells with or without hypoxic treatment. Co-culture with the exosomes from hypoxia-exposed glioma cells enhanced the migration ability of glioma stem cells, as compared with treatment with PBS or exosomes derived from normally cultured glioma cells (P < 0.05). The exosomes from hypoxia-exposed glioma cells also significantly increased the phosphorylation levels of the proteins in the JAK/STAT3 pathway. Conclusion Co-culture with exosomes from hypoxia-exposed glioma cells can enhance the migration ability of glioma stem cells partly by increasing the phosphorylation levels of the JAK/STAT3 pathway proteins.

Keywords

• exosomes
• glioma stem cell
• hypoxia
• cell migration
• jak/stat3