I3C suppresses activities of nuclear NF-κB and AP-1 in HTLV-1-infected T-cell lines. (A) Effects of 12-h treatment of HUT-102 cells with I3C (100 μM) on activation of NF-κB, AP-1 and Oct-1 assessed by EMSA using oligonucleotide probe for NF-κB, AP-1 or Oct-1. (B) Effects of I3C on the level of IκBα, phosphorylated IκBα (p-IκBα) and JunD by Western blot analysis. HUT-102 and TL-OmI cells were treated with I3C (100 μM) for the indicated periods, followed by protein extraction. Whole cell extracts (20 μg per lane) of treated cells were immunoblotted with specific antibodies. The arrowhead and arrow point to 38 kDa phosphorylated IκBα and 36 kDa IκBα protein, respectively. Representative data of three experiments with similar results. (C) Inhibition of nuclear translocation of NF-κB p65 by I3C. Representative results of immunofluorescence analyses in HUT-102 cells treated with I3C (100 μM) for 12 h using antibody against NF-κB p65. Original magnification, ×1,000.