(A) Cell death was evaluated after staining with propidium iodide in HuCCT1 and SB1 cells treated with dasatinib (1 µM, 24hrs). *p<0.05 (B) HuCCT-1 and SB1 cells were incubated with vehicle or the indicated concentration of dasatinib for 3 days. Cell proliferation was evaluated by cell counting after staining with Hoechst 33342 and was normalized to vehicle treatment. *p<0.01 (C) Cell lysates from HuCCT-1 cell lines incubated +/− dasatinib (1µM, 2hrs) were subjected to immunoblot for MCL-1. GAPDH were used as loading control. (D) Tumor bearing NOD/SCID mice from PDX42, PDX115, and PDX 135 were treated with daily gavage of vehicle or dasatinib (15 mg/kg, 14 days)(n=7/treatment) and tumor volumes recorded daily. Day 14 tumor volumes are displayed for all three PDX. *p<0.05 ***p<0.001 (E) Representative images following TUNEL staining in tumors from vehicle and dasatinib treated animals (upper panel), with quantification of TUNEL positive cells (lower panel). Original magnification 10×. Scale bar = 50 microns.