Fig. 3.

Modulation of heregulin-induced activation of NF-κB by herceptin and NBD peptide in SKBr3 cells. Nuclear extracts from SKBr3 cells were prepared and NF-κB–³²P–DNA-binding activity was determined by EMSA. (a) Binding of ³²P-labeled oligonucleotides to NF-κB at the indicated times after treatment of the cells with 1 nM heregulin is shown in duplicate (lanes 1–4). The identities of the NF-κB components were determined by supershift assays with antibodies to rel-family proteins p50 and p65 (data not shown). (b) NF-κB–³²P–DNA-binding activity was inhibited by simultaneous treatment of SKBr3 cells with the indicated concentrations of heregulin and herceptin, measured at 18 h after application. (c) Heregulin-stimulated NF-κB–³²P–DNA-binding activity in SKBr3 cells and simultaneous treatment with WT NBD (lanes 2–4) and mutant NBD (lanes 5–7). The DMSO concentration at the highest NBD concentration was 1%, and the control reaction (lane 1) contained the same amount of DMSO.