2.1. Cell culture

Human pancreatic cancer cell lines (SW1990, Panc1, and AsPC1) were obtained from the Cell Bank of the China Academy of Sciences (Shanghai, China). Panc1 cells and SW1990 cells were cultured as previously described [28]. The AsPC1 cell line, derived from metastatic human pancreatic carcinoma, was maintained in RPMI 1640 medium supplemented with 10% fetal bovine serum (FBS), 100 U/mL penicillin and 100 U/mL streptomycin. The cells were maintained in a humidified atmosphere with 5% CO₂ at 37 °C and passaged with 0.25% trypsin/EDTA every 3 days. The cells used in this study were passaged for <2 months after recovery.