Figure 5
Effect of heregulin β1 (HRGβ1) on growth of fulvestrant-treated MCF-7, T47D, BT474 and MDAMB361 cells. (A) Effect of heregulin β1 (HRGβ1) (0.1-10 ng/ml) on growth of MCF-7, T47D, BT474 and MDAMB361 cells maintained for seven days in the presence of either fulvestrant (100 nM) or vehicle control (ethanol). *P < 0.05 versus control (0), **P < 0.01 versus control (0), ***P < 0.001 versus control (0). (B) Effect of HRGβ1 (10 ng/ml) on growth of MCF-7, T47D, BT474 and MDAMB361 cells maintained for seven days in the presence of fulvestrant alone (100 nM), fulvestrant in combination wither either gefitinib (1 µM) or trastuzumab (100 nM) or appropriate vehicle control. The results are expressed as means ± SEM of triplicate wells and are representative of three separate experiments. ***P < 0.001 versus no treatment, ††P < 0.01 versus fulvestrant + herceptin, †††P < 0.001 versus fulvestrant + gefitinib.