Figure 4

Overlay plots and column graphs comparing the relative Her-2 receptor density in SK-Br-3 cells. A) Overlay plots of the unstained (black), stained (green) and the positive control, geldanamycin (red) with the associated geometric mean; B) Overlay plots of the unstained (black), stained (green) and cells exposed to trastuzumab (blue) with the associated geometric mean; C) Overlay plots of the unstained (black), stained (green) and cells exposed to heregulin-β1 (pink) or the heregulin-β1-trastuzumab combination (purple) with the associated geometric mean; D) Fluorescence (x-mean) intensity of triplicate runs, expressed as a percentage of untreated control (standardised to 100%). Concurrent heregulin-β1 abrogated relative Her-2 receptor density observed for trastuzumab. Trastuzumab, heregulin-β1 and the heregulin-β1-trastuzumab combination illustrated a progressive decrease in Her-2 receptor density at 24 hours. Similar significance trends were observed in SK-Br-3 cells exposed to EGF [56.82% (± 2.82)] and the EGF-trastuzumab combination [45.01% (± 1.06)].