Constitutive NF-κB activity in SCCHN cell lines. (a) Western blot analysis of phosphorylated IκBα (serine 32) and phosphorylated NF-κB p65 (serine 536). (b) Constitutive NF-κB promoter activity. The asterisk (*) denotes p < 0.01 compared to untreated cells. The data shown are from one representative experiment out of three independent experiments. The bars indicate the standard deviation. (c) Western blot analysis of IκBα degradation and phosphorylated NF-κB p65 (serine 536) expression following treatment with TNFα for the indicated time. (d) NF-κB binding activity. Nuclear protein was extracted from HNSCC cells, and an EMSA was performed as described previously. The image is representative of three independent experiments.