Figure 2. Rapamycin and PD0325901 display strong synergism in cell culture.
(A–D) Analyses of IC50 plots for the single agents (A and B) and the combination agents (C and D). (E) Graphic representation of the CI for rapamycin and PD0325901. These data are shown for CASP 1.1 cells; similar results were obtained for CASP 2.1 cells (not shown). Note that CI values were well below 0.1, indicating strong synergism of the drugs. (F and G) Bim is upregulated in response to drug treatment. CASP 1.1 or CASP 2.1 cells were transfected with a control or Bim siRNAi, followed by treatment with vehicle or the indicated compounds in the medium for 48 hours. (F) Western blot analyses done on whole cell extracts using the indicated antibodies or a control for protein loading (Ponceau S staining). (G) Results of MTT assays, indicating the enhanced cell survival in the drug-treated cells following treatment with Bim siRNAi. The P values compare the control (siCont) and the Bim siRNAi (siBim) in each group. Data are expressed as mean ± SEM.