Fig. 3

Response of knockin derivative cells to AKT inhibition alone or in combination with lapatinib. Drug response after 72 h shows minimal differential sensitivity to AKT inhibition with GSK690693 (red) among all cell lines. Equimolar combination of both GSK690693 and lapatinib (green) shows synergistic growth inhibition in cells overexpressing PIK3CA mutations or with knockin of the H1047R mutation but not the E545K mutation. Points at which significant synergistic interactions as measured by the combination index between lapatinib and GSK690693 are indicated with an *. Lapatinib monotherapy data from Fig. 1B is repeated here in each graph for comparison (blue)