Fig. 1
Temozolomide-resistant GBM cells transmit resistance to sensitive cells through exosomes. A Schematic model. Process to acquire Temozolomide-resistant cells. B Confirm the drug resistance of TMZ-resistant LN229 cells in vivo. Left, IVIS detects bioluminescence signals. Right, quantification of bioluminescent imaging signal intensities. C The expression of CD63 in TMZ-R cells and parental cells was detected by fusion expression of CD63-GFP protein. Nuclei were counterstained with DAPI. Scale bar, 10 μm. D Secretion of exosomes were detected by nanoparticle tracking analysis. E GFP mean fluorescence intensity (MFI; left y axis) and concentration by NTA (right y axis) of exosomes released by sensitive or resistant GBM cells. F Fluorescence images of Brain frozen section of brain from orthotopic GBM xenograft mice. Nuclei were counterstained with DAPI. Scale bar, 10 μm. G TMZ resistant cells (GFP) co-cultured with parental cells (mCherry) at a ratio of 1:1 with TMZ treatment (100uM) for 4 days. H TMZ-resistant cells expressed CD63-GFP fusion protein co-cultured with parental cells (mCherry) at a ratio of 1:1 for 4 days. Scale bar, 10 μm. I GBM cells were co-cultured with Res-exo or Sen-exo and TMZ (100 μM), and apoptosis was detected by caspase3/7 assay. Scale bar, 10 μm. J Patient-derived organoids was to confirm TMZ resistant after treated with Sen-exo / Res-exo. Scale bar, 50 μm. K–N Schematic model. Process of animal study. Nude mice were orthotopically xenografted with GBM cells (2 × 106 cells) and treated intravenously with Res-exo or Sen-exo (200 μg per mouse) and intraperitoneally with TMZ (40 mg/kg) daily. IVIS detects bioluminescence signals. Quantification of tumor size (L), and quantification of bioluminescent imaging signal intensities (M), and survival rate (N) of mice in indicated groups are shown. Results are presented as mean ± SD. *p < 0.05, and **p < 0.01. NS, not significant