Figure 4

Synergistic effect of celastrol on GA-induced cytotoxicity. a: Inhibitory effects of combined treatment with GA and celastrol on three oral squamous cell carcinoma cell lines. Cells were treated with different doses of GA (0, 2, 3 and 4 μM) and celastrol (0, 0.5 and 1 μM) for 72 hours. The interaction effects of GA and celastrol on all three cell lines were highly significant (P < 0.01, factorial ANOVA). b: Annexin V and PI staining of Tca8113 cells after treatment with 4 μM GA and 0.5 μM celastrol for 72 hours. The increase in apoptotic cells in combined treatment group was significant (P < 0.05, Student's t-test), compared with cells treated with GA alone. c: Inhibitory effects of Tca8113 cells after transient transfection with the dominant mutant pBabe-SR-IκBα (specific NF-Kappa B inhibitor) for 24 hours and treatment with 4 μM GA for 72 hours. Images are representative of three independent experiments.