2.1. Cell culture

NCI–H292 cells were purchased from the American Type Culture Collection (Manassas, Virginia, USA). NCI–H292 cells were cultured in RPMI-1640 (Sigma-Aldrich, Tokyo, Japan) supplemented with 10% fetal bovine serum (FBS, Cansera International, Etobicoke, Canada), 100 units/ml penicillin (Gibco Oriental, Tokyo, Japan), and 100 μg/ml streptomycin (Gibco Oriental) in a 5% CO₂ incubator (ShinMaywa, Tokyo, Japan). The adherent cells were subcultured every 3–4 days via treatment with a trypsin-EDTA solution (Gibco Oriental). Cells were seeded on two types of culture plates: a 96-well adhesive plate (MS-8096F, Sumilon, Tokyo, Japan) and a 96-well low-adhesive plate (MS8096R, Sumilon).