Cell Viability Assay

Cell viability was quantitated using a colorimetric MTT assay according to the procedures described previously. Briefly, 100 μL of target cell suspension (1 X 10⁴ cells) were added to each well of 96-well plate, and the plate was incubated for 24 h at 37 °C in a humidified 5% CO₂ atmosphere. Following incubation, 10 μM of MTT working solution was added to each well, and the plates were incubated for 3 h at 37 °C. After addition of inhibitor, the absorbance values were measured with a microplate reader at 570 nm. The percentage of survival was calculated using the following formula: survival percentage = (absorbance of CRL1101 treated wells – blank wells/absorbance of untreated wells – blank wells) X 100. The inhibition constant (IC₅₀) of the inhibitor was obtained by regression analysis using Excel.