*4.1. Cell Culture*

Human lung cancer cells (A549, H1299, H460, and H1650) were obtained from American Type Culture Collection (ATCC, Manassas, VA, USA). Cells were maintained in Roswell Park Memorial Institute (RPMI) 1640 medium (Welgene, Gyeongsangbuk-do, Korea) supplemented with 10% fetal bovine serum (Welgene) and 100 units/mL penicillin–streptomycin solution (Gibco, Grand Island, NY, USA) at 37 ◦C in a humidified 5% CO<sup>2</sup> atmosphere.
