MTT assay

The 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay was performed to measure the viability of osteosarcoma cells using the Cell Proliferation Kit I (Sigma), following the procedure described in the kit manual. Cells were grown in 96-wells in a final volume of 100 µl of culture medium per well in a humidified 37°C incubator. MTT labeling reagent was added to each well to obtain a final concentration of 0.5 mg/ml. Samples were incubated for 4 h in a humidified atmosphere. Then, 100 µl of solubilization solution was added to each well, followed by incubation (37°C) overnight. Absorbance of the samples was measured spectrophotometrically using a microplate reader.