Figure 5
Interaction of the endogenous ERβ with BRCA1. A: A549, H1793 and H1792 cells were treated with 10 nM E2, 10 ng/ml EGF, or the combination for 1 h. 300 μg WCE were incubated with rabbit polyclonal ERβ antibody (Millipore), immunoprecipitated using a Protein G beads or rabbit IgG (negative control), and immunobloted using BRCA1 ab. The membranes were stripped and reprobed for ERβ. BRCA1 bands were identified in the IP from E2-, EGF-, E2+EGF- treated A549 cells and E2- and EGF- treated 1944 cells, but not in H1793 and H1792 cell. B: A549 cells were treated with 10 nM E2 for 1 h. 300 μg NE were incubated with ERβ (H150) ab, immunoprecipitated, and immunobloted using BRCA1 ab. BRCA1 bands were identified in the NE from E2-treated A549 cells. C: 300 μg WCE from normal human lung tissue (N) or tumor human lung tissue (T) were incubated with ERβ (H150) ab, immunoprecipitated, and immunoblotted with BRCA1 ab. BRCA1 bands were identified only in the IP from two tumor samples from patients #1002800 and 1003775. The membranes were stripped and reprobed with β-actin (ACTB) as a loading control and then stripped and re-probed for ERβ. ERβ bands were identified in the WCE from normal or tumor lung tissue. IgG bands overlapped with ERβ in IP samples.