FIG. 6.
The nuclear Stat3/ErbB-2 complex regulates in vitro breast cancer proliferation. (A) Endogenous ErbB-2 expression was silenced by transfection with ErbB-2 siRNAs, and expressions of either hErbB-2WT or hErbB-2ΔNLS were restored by cotransfection with the respective plasmids. Cells were treated with MPA for 48 h, and the incorporation of [3H]thymidine was used as a measure of DNA synthesis. Data are presented as means ± standard deviations (P < 0.001 for b versus a). (B) C4HD cells were transfected with control siRNA (top) and cotransfected with hErbB-2ΔNLS (bottom) before MPA stimulation for 48 h and were then stained with PI and analyzed for cell cycle distribution by flow cytometry. The data from the experiments shown are representative of data from a total of three experiments.