ERK reactivation following EGFR TKI treatment. ERK reactivation following EGFR TKI treatment. A, cells were treated with DMSO (media), 100 nmol/L WZ4002, 1 μmol/L of WZ4002, or 1 μmol/L gefitinib weekly (mean ± SD, n = biologic triplicates, 60 wells each). B, PC9 cells were treated with 1 μmol/L WZ4002 or 1 μmol/L gefitinib, and AKT and ERK1/2 phosphorylation (p) was assessed. HSP90 was assessed as a loading control. Image is representative of three independent experiments. C, cell lines were treated with 100 nmol/L WZ4002 (W), 30 nmol/L trametinib (T), or a combination thereof (C) for the indicated time, and phosphorylation of AKT and ERK1/2 was assessed by immunoblotting. Image is representative of two independent experiments. Erin M. Tricker et al. Cancer Discovery 2015;5:960-971 ©2015 by American Association for Cancer Research