Effect of NVP-AEW541 and lapatinib combined treatment on the growth of pancreatic cancer cell lines. (A) Dose–response curves and CDI values for NVP-AEW541 and lapatinib combinations. Twenty-four hours after seeding, cells were treated with increasing concentrations of lapatinib alone (●) or combined with a fixed concentration of NVP-AEW541 (▲) equivalent to its IC20. Data are presented as means ± standard deviation of a representative experiment (n = 3). (B) Molecular effects of NVP-AEW541 and lapatinib treatments. Cells were treated 24 h after seeding with a concentration equivalent to the IC20 of NVP-AEW541, lapatinib, or their combination. After 72 h, 50 ng/ml of IGF-I, EGF or both were added for 20 min, and expression of IGF-IR and EGFR pathway components was analyzed by Western blot. (C) Schematic representation of the molecular mechanism involved in NVP-AEW541 and lapatinib synergistic effect.