Dp44mT and DpC overcome resistance to the clinically used EGFR inhibitor, erlotinib. PANC-1 (A), HT-29 (B), MIAPaCa-2 (C), and HCT-116 (D) cancer cells were incubated with either Dp2mT, DFO, Dp44mT, DpC, or the EGFR inhibitor erlotinib for 72 h/37 °C at a range of concentrations (0–80 μm), and cell proliferation was examined via an MTT assay (see “Experimental Procedures”). Data are presented are mean ± S.D. of three experiments.