Fig. 3
IL-18 promotes TMZ resistance in glioma by promoting proliferation and inhibiting apoptosis. (A) U87 and U118 cells were incubated with human IL-18 protein at doses from 0 to 105 ng/mL for 48 h, and then treated with TMZ at different concentrations (0, 100, 200, 300, 400, and 500 µg/mL) for 48 h. The TMZ sensitivity of U87 and U118 treated with different IL-18 doses were indicated through a Cell Counting Kit-8 assay. **P < 0.01 vs. 0 ng/mL. (B) Cell viability of U87 and U118 incubated with 75 ng/mL IL-18 for 24, 48, 72, and 96 h. *P < 0.05 compared with control groups. (C) U87 and U118 cells were incubated with DMSO, IL-18, or IL-18 + LY294002 (PI3K inhibitor) for 48 h. The rate of EdU-positive cells in these groups was determined via an EdU staining assay. Scale bar = 100 μm. (D) EdU-positive cell rate. (E) Apoptosis rate. (F) U87 and U118 cells were incubated with DMSO, IL-18, or IL-18 + LY294002 (PI3K inhibitor) for 48 h. Apoptosis rate after TMZ (50 µg/mL) treatment for 48 h measured by the Annexin V-FITC/PI double staining. **P < 0.01. Data are presented as means ± S.D. of three independent experiments. IC50, the half maximal inhibitory concentration; IL, interleukin; TMZ, temozolomide; PI, Propidium Iodide