MTT assay

Cell growth/viability inhibitory effect of drug (FL118, gemcitabine, Abraxane, cisplatin) alone and in combination, respectively, on cell growth was determined by MTT cell viability assay. Viable cells (2500 cells per well) were plated in each well in 96-well plates. After an overnight incubation, cells were treated with and without relevant drugs alone and in combination, respectively, at various concentrations and incubated for 72 h. MTT, a colorimetric substrate, was added to a final concentration of 0.4 mg/mL to each well. Cells in 96-well plates were further incubated in a 5% CO₂ incubator at 37 °C for 4 h, and then the medium was aspirated. The MTT metabolic product formazan was solubilized by adding 200ul of DMSO to each well. Absorbance in the relevant wells was measured at 570 nm using an Ultra Microplate Reader (Bio-Tek Instruments).