2.1 Cell culture
BGM cells purchased from the American Type Culture Collection (ATCC, USA) were maintained in Roswell Park Memorial Institute (RPMI) 1640 medium (Gibco, USA) supplemented with 10% fetal bovine serum (FBS, Gibco, USA) and 1% penicillin/streptomycin (Gibco, USA) at 37°C in a 5% CO2 incubator. Mycoplasma testing was performed, and cell cultures were confirmed to be negative.