Figure 4
Normalized HER2 bound QD fluorescence intensity distribution. Shown is the difference in trastuzumab induced HER2 removal from the membrane between bulk cells, characterized by more than one membrane ruffle per cell (upper graphs), and flat cells, with no or only one membrane ruffle per cell (lower graphs). The main data set (left side) depicts the early reactions after 2 min (orange), and 5 min (green) of drug incubation, compared to control cells without drug incubation (blue). The validation dataset (right), determined after 60 min of drug incubation, shows a marked shift of the median of the ruffled bulk cell population towards median values of the flat cell population, indicating a more than 50% reduction of membrane-bound HER2 within the bulk subpopulation. The mean HER2 signal distribution of the control flat cells started at already lower mean intensity values, compared to the ruffled cells. At early time points these cells exhibited only small, negligible shifts towards lower intensity values, after 60 min this subpopulation completely failed to show a difference towards the untreated flat cell population.
