Figure 3: Effect of SKIP knockdown on TGF-β1-induced PAI-1 expression. (a) Expression of PAI-1 mRNA transcripts evaluated by RT-PCR in PC-3 cells transfected with either control siRNA (siR-C) or siRNA-SKIP (siR-SKIP) before and after stimulation (24 h) with TGF-β1. GAPDH was amplified as a control for the amount of cDNA present in each sample. (b) Transactivation of PAI-1 promoter in PC-3 cells is transiently transfected with empty vector (EV) as a control or SKIP-Ha tagged expressing vector (SKIP-V). MMP-9 promoter activity was assayed in cells unstimulated and stimulated with TGF-β1 for 48 h. β-Galactosidase was used as an internal control of transfection.