Fig. 2: GRP78-induced macrophage-derived exosomes modulate chemoresistance and stemness in CRC cells.

A Transmission electron microscope (TEM) micrographs of M0-exos and GRP78-exos. B Measurement of particle size of M0-exos and GRP78-exos by nanoparticle tracking analysis (NTA). C Expression of exosome marker proteins TSG101, CD63, and CD81 in THP-1 cells, M0-exos and GRP78-exos was detected by western blot. THP-1 cells served as a control. D Internalization of M0-exos and GRP78-exos was observed by fluorescence microscopy, and the proportion of them entering cells was counted. DAPI: nucleus. Phalloidin: representing cytoskeleton. Scale bar: 5 μm. E The effects of M0-exos and GRP78-exos on the viability of HCT-8 and DLD1 cells were detected by MTT and IC₅₀ values were calculated. F The effects of M0-exos and GRP78-exos on 5-FU-induced apoptosis in HCT-8 and DLD1 cells were detected by flow cytometry. G Statistical plots of apoptosis rates of HCT-8 and DLD1 cells for (F). H The effects of M0-exos and GRP78-exos on the expression of pro-apoptotic proteins cleaved-PARP and cleaved-caspase 3 and anti-apoptotic protein Bcl-2 in the presence of 5-FU by western blot. I The effects of M0-exos and GRP78-exos on the protein expression of stemness markers CD133, CD44 and ALDH1A1 in HCT-8 and DLD1 cells were examined by western blot. J The effects of M0-exos and GRP78-exos on the expression of stemness markers CD133, CD44 and ALDH1A1 mRNA in HCT-8 and DLD1 cells were detected by qRT-PCR. Data are expressed as SD ± mean, n = 3. *p < 0.05, **p < 0.01, ***p < 0.001.