Fig. 3.

Transfection of a dominant negative mutant construct of IκB-α (IκB-αM, a superrepressor of NF-κB) reverses TGF-β-induced pNF-κB-luc reporter gene activity. To further confirm whether TGF-β could activate the NF-κB pathway, cells were transfected with NF-luc with (+) or without (−) cotransfection with IκB-αM 24 h before TGF-β treatment. Twenty-four hours after TGF-β treatment, cells were lysed and subjected to luciferase assay. TGF-β induces pNF-κB-luc reporter gene activity, suggesting activation of NF-κB. However, IκB-αM transfection inhibited TGF-β-induced activation of NF-κB.