Figure 3

Potentiation to doxorubicin-induced Akt phosphorylation in MCF7 cells after expressing high levels of HER2. Control vector-transfected MCF7 cells (MCF7neo) and MCF7 transfectants expressing high levels of human epidermal growth factor receptor-2 (MCF7HER2) were left untreated or were treated with 0.5 or 1 μM doxorubicin (Doxo) for 24 hours. Separate dishes of MCF7neo and MCF7HER2 cells were pretreated with 20 nM trastuzumab (Herceptin) 24 hours before treatment with doxorubicin. After treatment the cells were harvested, lysed and subjected to Western blot analyses with antibodies against HER2, Ser473-phosphorylated Akt (p-Akt) and total Akt. The densitometric levels of p-Akt were normalized to the respective levels of total Akt in each lane and are shown in the bar graph.