4.5. Cell Viability Assay

Cell viability inhibition effect of O-acetyl RT on NSCLC cells was determined by MTT assay. In brief, cells were seeded into 96-well plate at 1 × 10⁴ cells/well, allowed to adhere overnight and then treated with different concentration of O-acetyl RT (0, 0.01, 0.05, 0.1, 1, 5, 10, 25 µM) for 24 h. After that, 100 μL of MTT solution (400 µg/ml) was added, incubated for another 4 h at 37 °C. The formazan crystal product was dissolved in 100 μL of DMSO. The optical density was measured at 570 nm using a microplate reader (Anthros, Durham, NC, USA). For O-acetyl RT sensitization in H292 cells, the cells were exposed to O-acetyl RT for 24 h, and then after washout of O-acetyl RT, cells were incubated in medium with or without cisplatin (50 µM) for an additional 24 h.