Hhl 5 cells

Human laryngeal cancer cell lines, TU212 and M4e, human normal larynx epithelial HBE cells, and human normal liver HHL-5 cells, were purchased from the American Type Culture Collection (ATCC; Manassas, VA USA). The mouse normal larynx epithelial RTE cells, and human laryngeal cancer HEP-2 cells were purchased from the Nanjing KeyGen Biotech, Co., Ltd. (Nanjing, China). TU212, HEP-2 and RTE cells were routinely cultured in RPMI-1640 medium (Gibco, Carlsbad, CA, USA), containing 10% fetal bovine serum (FBS; Gibco), 1% penicillin/streptomycin. The cell lines M4e, HBE and HHL-5 were cultured in Dulbeccos modified Eagles medium (DMEM; Gibco) supplemented with 10% FBS, 100 U/ml penicillin and 100 µg/ml streptomycin. All cells were kept in a humidified atmosphere with 5% CO₂ and 95% humidity at 37°C in an incubator. Galangin (>98% purity), purchased from the Hangzhou DayangChem, Co., Ltd., (Hangzhou, China) was used for the treatment of human laryngeal cancer dissolved in dimethyl sulfoxide (DMSO) and then stored at −20°C for experimental treatment use. The final DMSO concentration in cells is <0.1% (v/v) in each treatment.