Cell lines and culture

Human esophageal squamous cancer cell lines TE-1 and ECA-109 purchased from the American Type Culture Collection (ATCC; Manassas, VA, USA) were maintained in Dulbecco's modified Eagle's medium (DMEM; HyClone, Logan, UT, USA) supplemented with 10% fetal bovine serum (FBS; ScienCell, Carlsbad, CA, USA). Reagents for cell culture were purchased from Gibco (Grand Island, NY, USA). The cells were incubated at 37°C with 5% CO₂.