Fig. 6

Synergy between pertuzumab and lapatinib in vitro. a Cell viability assays performed on a panel of ERBB2+ breast cancer lines with lapatinib at the concentrations indicated for 5 days (n = 6, mean ± SD). b Western blotting showing the co-immunoprecipitation of GRB2 and SHC with ERBB2 from AU565 cells treated with pertuzumab (100 nM) or lapatinib (100 nM) as indicated, for 30 min. Immunoprecipitation was performed with either a mouse IgG control or ERBB2 monoclonal antibody. Blots are representative of three experiments. c BT474 cells and d AU565 cells were treated with pertuzumab (100 nM) or lapatinib (100 nM) as indicated, for 30 min. Western blotting was performed with the antibodies indicated. Blots are representative of three experiments. e BT474 cells and f AU565 cells were used to perform combinatorial cytotoxicity assays with lapatinib and pertuzumab at the concentrations indicated for 5 days (n = 6, mean). Raw data is presented in Additional file 2: Figure S6C, D. Synergy was calculated as a Combination Index (CI), using Compusyn (v1)