Fig. 2

a Fluorescence image of PKH26-labeled MG63 cell-derived exosomes co-cultured with MG63 cells. b Fluorescence image of PKH26-labeled MG63/CDDP cell-derived exosomes co-cultured with MG63 cells. c Fluorescence image of PKH26-labeled HOS cell-derived exosomes co-cultured with HOS cells. d Fluorescence image of PKH26-labeled HOS/CDDP cell-derived exosomes co-cultured with HOS cells (e and g). The fluorescence of Cy3 in MG63 cells was observed under a confocal microscope. The mRNA expression level of miR-199a in MG63 cells in the lower compartment of the Transwell chamber (f and h). The fluorescence of Cy3 in HOS cells was observed under a confocal microscope. The mRNA expression level of miR-199a in HOS cells in the lower compartment of the Transwell chamber. **P < 0.01 versus the control group. CDDP, cisplatin