The LM3 cells were a gift received from Prof. Zheng Shusen [24 (link)], and the SK-Hep1 was obtained from ATCC (Manassas, VA). Both cell lines were maintained in DMEM cell culture medium (Invitrogen, Grand Island, NY) with 10% fetal bovine serum (FBS), 1% penicillin/streptomycin and 1% glutamine. All cell lines were cultured in a 5% (v/v) CO2 humidified incubator at 37oC.