4.8. In Vitro Cytotoxicity Assay

Cells (with a density around 6 × 10³ per well) were seeded in the 96-well plate 24 h prior to the drug treatment. Cells were then treated with sorafenib or foretinib with the indicated dosage for 48 h. Cell viability was determined using the CellTiter96^® cell proliferation assay kit (Promega, CA, USA) according to the instructions from the manufacturer. The IC₅₀ value of cells treated with or without sorafenib or foretinib was calculated using GraphPad Prism software (San Diego, CA, USA). All the experiments were performed in triplicate and repeated three times.