Figure 3
Effect of fulvestrant on heregulin β1 (HRGβ1) signalling in MCF-7 and T47D cells. (A) Western blots showing the effect of increasing concentrations of heregulin β1 (HRGβ1) (0.1 to 10 ng/ml for five minutes) on total and phosphorylated ErbB3, ErbB4, AKT and extracellular signal-regulated kinases 1 and 2 (ERK1/2) protein expression in MCF-7 and T47D cells, maintained for 7 days in the presence of either fulvestrant (100 nM) of vehicle control (ethanol). (B) Graphs showing cyclin D1 protein expression in MCF-7 and T47D cells maintained for seven days in the presence of either fulvestrant or vehicle control and subsequently exposed to either HRGβ1 or vehicle control for five minutes. β-actin was used as a loading control. (C) Western blots showing the effect of HRGβ1 (10 ng/ml) on growth of MCF-7 and T47D cells maintained for seven days in the presence of either fulvestrant or vehicle control (ethanol). The results are expressed as means ± SEM of triplicate wells and are representative of three separate experiments. **P < 0.01 versus control, ***P < 0.001 versus control, †††P < 0.001 versus fulvestrant.