The normal human liver cell line LO2 was acquired from the American Type Culture Collection (ATCC). Hepatocellular carcinoma cell lines HepG2 and MMC-7721 were acquired from the China Center for Type Culture Collection. Cells were cultured in Dulbecco’s Modified Eagle Medium (DMEM) complemented with 10% fetal bovine serum (FBS) and 100 IU/mL penicillin-streptomycin at 37°C with 5% CO2. To create the sorafenib-resistant cells (HepG2-R), HepG2 cells were treated with incremental concentrations of sorafenib (Selleck, Houston, TX, USA); starting with 0.5 μM, the concentration was doubled every 2 weeks until it reached 8 μM. Then, the HepG2-R cells were treated with 8 μM of sorafenib biweekly to maintain the resistant ability [14 (link)].
To obtain exosomes, cells were cultured in 15-cm dishes with 30 mL of the whole culture. After reaching 70% confluence, cells were washed with phosphate-buffered saline (PBS) and cultured in DMEM complemented with 10% exosome-depleted FBS for 48 hours. The exosome depleted FBS was obtained by ultracentrifugation at 100 000×g for 12 hours.
To obtain exosomes, cells were cultured in 15-cm dishes with 30 mL of the whole culture. After reaching 70% confluence, cells were washed with phosphate-buffered saline (PBS) and cultured in DMEM complemented with 10% exosome-depleted FBS for 48 hours. The exosome depleted FBS was obtained by ultracentrifugation at 100 000×g for 12 hours.
