Exosome Isolation, Labeling

The detailed protocol of continuous ultracentrifugation for extracting exosomes can be shown in our previous work (Bao et al., 2018). The exosomes were labeled with a PKH-67 labeling kit (Sigma-Aldrich) to observe the uptake of exosomes. After CNE2 cells were cocultured with the labeled exosomes for 1 h, CNE2 cells were fixed, and the nuclei were stained with DAPI. Finally, images were collected with a Leica TCS-SP5 LSM microscope. In the subsequent uptake experiment of co-cultured exosomes, we added 80 ug of exosomes per 1 × 10^6 cells.