Fig. 4

ARNTL2 highly expressed PC cells are sensitive to erlotinib in vitro. Cell proliferation of HPNE cells (A), CFPAC-1 (B), AsPC-1 (C), PANC-1 (D), BxPC-3 (E) and PATU-8988 T (F) treated for 72 h with erlotinib at 2.5 μM, 5 μM and 10 μM, respectively; G-H Colony-formation assay of 5 pancreatic cancer cell lines and one normal pancreatic duct cells were grown in the absence or presence of erlotinib at the indicated concentrations for 7–10 days, fixed and stained; I ARNTL2 expression levels across the PC cell lines; J IC50 assay of erlotinib in pancreatic cancer cell lines and normal pancreatic duct cells (K) Synergistic response to erlotinib treatment in pancreatic cancer cell lines and normal pancreatic duct cells. All data are presented as the mean ± SEM of triplicate experiments. *p < 0.05; **p < 0.01; ***p < 0.001 by repeated measures with Student’s t test