Figure 4.

ROS accumulation leads to TGFβ activation in IKKβ-null cells. (A) Wild type and Ikkβ ^−/− cells and (B) wild type and p65 ^−/− cells were examined for mRNA of oxidative stress marker Hmox-1 and/or redox scavenger gene Sod2. (C) The wild type and Ikkβ ^−/− cells with or without Ad-IKKβ infection were examined for p65 binding of the Sod2 enhancer and RNA Pol II occupancy of the Sod2 promoter. (D) The Ikkβ ^−/− cells were transfected with luciferase reporters for AP-1, SMAD and Tgfβ2 promoter, together with either an empty vector or SOD2 expression plasmids. The luciferase activities in SOD2 transfected cells were compared to those in empty vector transfected cells, designated as 1. (E) The wild type cells were either un-transfected or transfected with Tgfβ2 promoter reporter, and treated with pro-oxidant BSO. The Tgfβ2 mRNA expression and promoter activity were examined. The Ikkβ ^−/− cells were either un-transfected or treanfected with the luciferase reporter plasmids for Tgfβ2 promoter or SMAD (SEB-luc). The cells were treated with anti-oxidant NAC, and were examined for (F) Tgfβ2 mRNA expression and luciferase activity, and (G) migration by the in vitro wound healing assays. Results represent the mean values ± SD from at least three independent experiments. *P < 0.05, **P < 0.01 and ***P < 0.001 were considered significantly different from the wild type or control samples