Fig. 8. Transcriptional regulation of Vegfa and Tgfb promoter activity by KLF5. (A) JEG cells were transfected with promoter plasmid pGL2-Vegfa-Luc and increasing amounts of the expression plasmid pcDNA-Klf5. The plasmid pcDNA was used as an empty control. KLF5 increased the Vegfa promoter activity in a dose-responsive manner. (B) H441 cells were transfected with promoter plasmid pGL2-Vegfa-Luc and Klf5-targeting siRNA, with or without an HIF2 expression vector. A control negative siRNA was used as empty control. Inhibition of KLf5 expression moderately, but significantly inhibited Vegfa promoter activity. Klf5 siRNA significantly inhibited HIF2-dependent activity of the Vegfa promoter. (C) H441 cells were transfected with the promoter plasmid pGL3-3TP-Luc and the Klf5 expression vector, with or without TGFβ1 (2 ng/ml). Expression of Klf5 inhibited pGL3-3TP luciferase activity and inhibited TGFβ1-dependent activity of pGL3-3TP. The plasmid pcDNA was used as a control. (D) H441 cells were transfected with the promoter plasmid pGL3-3TP-Luc and Klf5-targeting siRNA, with or without TGFβ1 (2 ng/ml). A control negative siRNA was used as empty control. Inhibition of Klf5 expression moderately, but significantly enhanced 3TP promoter activity. Inhibition of Klf5 expression significantly enhanced TGFβ1-dependent activity of 3TP promoter (^*P<0.05).