Figure 4: Effect of SKIP knockdown on TGF-β1-induced MMP-9 production. (a) MMP-9 zymography assay and RT-PCR analysis in PC-3 cells transfected with either siR-C or siR-SKIP and treated with TGF-β1 for 24 h. GAPDH was amplified as RT-PCR control for the amount of cDNA present in each sample. (b) Transactivation of MMP-9 promoter in PC-3 cells is transiently transfected with empty vector (EV) 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.