Activation of the IGF-1R, PI3K, or MAPK pathway is sufficient for conferring resistance to the EZH2 inhibitor GSK126. (A) SU-DHL-10 cells expressing the specified genes or an empty vector were analyzed for the indicated proteins by immunoblotting. (B) SU-DHL-10 cells expressing the specified genes or an empty vector (control) were analyzed for their sensitivity to GSK126 using an MTT assay after treatment with GSK126 at the indicated concentrations for 72 hours. The cell viability relative to DMSO-treated cells is shown. (C) SU-DHL-10 cells expressing the specified genes or an empty vector as a control (Vector) were treated with GSK126 (5 μM) for 3 or 10 days and analyzed for apoptosis induction by annexin V–FITC staining. (D) SU-DHL-10 cells expressing the designated constructs were treated with the EZH2 inhibitor GSK126 (1 μM) for 48 hours and analyzed by immunoblotting for H3K27me3, H3, and ACTINB. AUC was calculated to allow for the comparison between the 2 curves and the P values were calculated using a Student t test. Data are presented as mean ± SEM. *P < .05; ***P <.001.