Figure 2

Dual inhibition of ErbB-2/ErbB-3 is required to fully inhibit Akt activity. (a) ErbB-3 and ErbB-2 surface expression level was monitored by fluorescence-activated cell sorting in ErbB-3-silenced (shErbB-3) and control (sh4Mut) cells. MFI (mean fluorescence intensity) is expressed as fold change over control (cells stained with secondary antibody alone). (b) Cell proliferation assay by MTT; cells were serum starved for 24 h and then stimulated with NRG-1β or serum for 72 h. The values represents mean±s.d. of quadruplicate measurements from one of two independent experiments. *P<0.05. (c) Cells were serum starved for 24 h, incubated with trastuzumab for 2 h as indicated and then stimulated with 10 ng/ml NRG-1β for 5 min. Lysates were then immunoblotted as indicated.