Figure 5. Troglitazone inhibits 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced activator protein-1 (AP-1) activation in MCF-7 cells. (A) Phosphorylation of c-Jun, a major subunit of AP-1, was determined by western blots with proliferating cell nuclear antigen (PCNA) as the loading control for nuclear proteins. (B) AP-1-luc reporters and a Renilla luciferase thymidine kinase reporter vector were co-transfected into MCF-7 cells. Cells were treated with troglitazone with TPA and AP-1 promoter activity was measured with dual-luciferase reporter assays. (C) Cells were treated with troglitazone with TPA and nuclear extracts were prepared after 3 hours. AP-1 DNA binding was analyzed by electrophoretic mobility shift assay. Values are mean±standard error of the mean of three independent experiments.

^*p<0.01 vs. TPA.