Figure 2. Troglitazone inhibits 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced matrix metalloproteinase-9 (MMP-9) expression in MCF-7 cells. MCF-7 cells were pretreated with troglitazone and then TPA was added for 24 hours. (A) MMP-9 secretion by gelatin zymography (top). MMP-9 protein expression was determined by western blot. β-Actin was the internal control (bottom). (B) MMP-9 mRNA was analyzed by real-time polymerase chain reaction with glyceraldehyde 3-phosphate dehydrogenase (GAPDH) as the internal control. (C) Wild type MMP-9-luc reporters and a Renilla luciferase thymidine kinase reporter vector were co-transfected into MCF-7 cells. Cells were treated with troglitazone and TPA and MMP-9 promoter activity was measured with dual-luciferase reporter assays. (D) Peroxisome proliferator-activated receptor γ antagonist GW9662 was added to cells for 30 minutes before troglitazone treatment. Lysates were analyzed by western blot with anti-MMP-9. β-Actin was the loading control. Values are mean±standard error of the mean of three independent experiments.

^*p<0.01 vs. TPA.