Determination of the Half-maximal Inhibitory Concentration (IC50)

Cells treated with shRNA or plasmid were seeded in 96-well plates (5,000 cells/well). Three multiple parallel wells were set up in each group. The cells were treated with different concentrations of cisplatin (32, 16, 8, 4, 2, and 1 μg/mL) (Sigma) for 24 h or temozolomide (TMZ) (160, 80, 40, 20, 10, and 5 μg/mL) (MCE, Shanghai, China) for 48 h, and then the CCK8 assay was used to determine the cell viability in each well. The IC₅₀ was calculated using the regression model in SPSS 17.0 (SPSS Inc., Chicago, USA).