ZF4 cell line

The ZF4 cell line was purchased from American Type Culture Collection (Manassas, VA, USA), and cultured according to established protocols (Driever and Rangini, 1993). The medium (DMEM/F12) was obtained from Corning Inc. (New York, USA). Penicillin-Streptomycin solution were purchased from Sigma (St. Louis, MO, USA). Fetal bovine serum was purchased from Corning Inc. (New York, USA). Cells were kept in a cell incubator with 5% CO₂ at 28°C.