Figure 6. TNF-α upregulates VEGF by mediating ROS-dependent transcriptional activation of β-catenin. Representative western blots of (A) β-catenin and (B) vascular endothelial growth factor (VEGF) in RPE cells pretreated with JW67 (20 µM) or XAV939 (1 µM) or control dimethyl sulfoxide (DMSO) for 30 min before incubation with tumor necrosis factor alpha (TNF-α; 20 ng/ml) for an additional 1, 3, or 6 h. C: Coimmunoprecipitation of β-catenin and T cell factor 1 (TCF1) in RPE cells pretreated with apocynin (APO, 100 µM) or XAV939 or control DMSO for 30 min (representative blot). D: Coimmunoprecipitation of β-catenin and TCF1 in RPE cells transfected with p22phox siRNA and incubated with TNFα (20 ng/ml) for 2 h (representative blot).