Fig. 6

NF-κB is activated in mammary adenocarcinomas but not squamous cancers. a p65, p52 and RelB NF-κB immunofluorescence in microacinar (MA) and squamous (S) tumors from the indicated mice. Note the strong nuclear staining for p52 in WT MA versus bcl-3^−/− MA, the presence of cytoplasmic p65 and p52 and absence of RelB in squamous tumors. b Anti-Bcl-3 immunofluorescence in S and MA tumors from WT and bcl-3^−/− mice. All bars = 100µ. Pixels from expanded boxed areas show overlap between chromatin (DAPI) and anti-Bcl-3 IF within WT MA tumor cells positive for Bcl-3. c EMSA analysis of nuclear extracts from the indicated tumor subtypes. S/MA > 70% squamous; MA/S > 70% microacinar; Ap, anaplastic. The NF-κB consensus sequence was used as a DNA probe. Com: cold probe was incubated with labeled probe and WT (MA tumor) nuclear extract prior to gel loading. d Supershift analysis using normal serum (NS), anti-p50 or anti-p52 incubated with nuclear extracts from MA and Ap tumors and labeled NF-κB probe. NF-κB complexes are indicated. White arrows indicate supershifted complexes. n.s. non-specific bound probe