Neratinib combination with MEK or PI3K inhibitors induces synergistic growth inhibition in HER2-L755S mutant cells. (a) Cell proliferation of HER2-L755S treated with neratinib (100nM), AZD6244 (1uM), or in combination as indicated. Representative data are expressed as log2-fold change normalized to day 0 of three technical replicates. (b) Cell proliferation of HER2-L755S treated with neratinib (100nM), GDC0941 (1uM), or in combination as indicated. Representative data are expressed as log2-fold change normalized to day 0 of three technical replicates. (c) Western blotting showing the expression of HER2, EGFR, AKT, p70S6K, MEK1/2 and p42/44 MAPK in MCF10A bearing HER2-L755S treated with MEK inhibitor neratinib (30nM) and AZD6244 (1uM) (left) or PI3K inhibitor GDC0941 (1uM) for 4 h (right).