The human neuroblastoma SH-SY5Y and human liver carcinoma HepG2 cell lines were purchased from American Type Culture Collection (Manassas, VA, USA). Cells were cultured in Advanced Dulbecco's modified Eagle's medium (Gibco, Thermo Fisher Scientific, Waltha m, MA, USA) supplemented with 10% fetal bovine serum (FBS, Gibco), 2 mM L-glutamine, 50 U/mL penicillin and 50 μg/mL streptomycin (Sigma, St. Louis, MO, USA) in a humidified atmosphere of 95% air and 5% CO 2 at 37 °C, and grown to 80% confluence. Prior to cell treatment, complete medium was replaced with serum-reduced medium (i.e., with 2% FBS).