Cell Viability Assay

Cell proliferation was measured using the MTT assay. Cells were seeded in 96-well plates at 6 × 10³ cells per well and incubated overnight to achieve 80% confluency. The indicated drugs were added to achieve final concentrations of 0–100 μM. Cells were incubated for the indicated times prior to the determination of cell viability using the MTT reagent according to the manufacturer's protocol (Roche, Basel, Switzerland; 11,465,007,001). Absorbance was measured at 550 nm. Viable cells were counted by trypan blue exclusion. Data were expressed as a percentage of the signal observed in vehicle-treated cells and are shown as the means ± SEM of triplicate experiments.