EGFR inhibitor AG1478 suppresses growth of human pancreatic cancer cells in vitro and constitutive STAT3Tyr705phosphorylation is not suppressed by EGFR inhibitor AG1478 in PDAC cells. A, Exponentially growing PDAC cells were treated with indicated concentrations of EGFR inhibitor AG1478 for 96 h and MTT assays were performed to measure cell growth. Data are presented as % growth of control. Bars represent SD of eight replicates, and experiments repeated for three times. (*) = highly significant with a p < 0.001. B, PDAC cells were serum deprived for 48 h and pre-treated with EGFR inhibitor, AG1478 (10 μM) for 4 h followed by stimulation with EGF (50 ng/mL) for indicated periods of time in the presence or absence of EGFR inhibitor. Vehicle DMSO was used where EGFR inhibitor was not used. Equal amounts of proteins were loaded and the blots were probed for phosphorylated and total forms of EGFR, STAT3, AKT and ERKs. As a loading control, human β-actin levels are shown.