Fig. 2

CAF-derived exosomes increase HNC cell proliferation and cisplatin resistance. a CAL 27 and HN4 cells were grown in CAF-CM or control CM for 6 days, and cell viability was examined. b CAL 27 and HN4 cells were grown in CAF-CM or control CM for 6 days, and then MTT assays were performed to detect the cisplatin response of these cells. c CAL 27 and HN4 cells were grown in control CM, CAF-CM, or exosome-depleted CAF-CM for 6 days, and cell viability was examined. MTT assays were performed to assess the tolerance of these cells to cisplatin. d HNC cells were co-cultured with DMSO-treated HNC cells, DMSO-treated CAFs, or GW4869-treated CAFs for 6 days, and then HNC cell viability was assessed. The survival percentage of co-cultured HNC cells was measured by MTT assay upon cisplatin treatment. e NanoSight particle-tracking analysis of size distribution and the number of exosomes from CAFs or cisplatin-treated CAFs (10 μM). f NanoSight particle-tracking analysis of the number of exosomes from NFs, CAFs, or HNC cells with or without cisplatin treatment (10 μM). g Exosomal protein concentration in CM from NFs, CAFs, or HNC cells with or without cisplatin treatment (10 μM). h CAL 27 and HN4 cells were incubated with DiO-labeled exosomes (25 μg/mL) from CAFs for 24 h, and the green exosome signal was detected by confocal microscopy (scale bar, 20 μm). i Flow cytometric analysis of DiO-positive CAL 27 or HN4 cells after incubating with DiO-labeled exosomes (25 μg/mL) from CAFs for the indicated time. j HNC cells were treated with exosomes (25 μg/mL) from HNC cells, CAFs, or cisplatin-treated (10 μM) CAFs for 6 days. Cell viability was measured, and MTT assays were performed to evaluate the cisplatin response of these cells. k HNC cells were treated with exosomes (25 μg/mL) from HNC cells, cisplatin-treated (10 μM) HN4-res cells, or cisplatin-treated (10 μM) CAFs for 6 days. The viability and survival percentage of these cells were measured by MTT assays. (NT, without cisplatin treatment; CT, cisplatin treatment; ns, no significant difference; *p < 0.05; **p < 0.01; ***p < 0.001; ****p < 0.0001)