Fig. 1

IGF-1R increase in resistant cells upon exposure to anti-EGFR antibody cetuximab. a UMSCC6 cetuximab resistant and sensitive cell lines at passage 17 were exposed to increasing concentration of cetuximab to measure cell viability by absorbance in a crystal violet assay (■) Resistant cells in the absence of cetuximab, (●) sensitive cells in the presence of cetuximab (▲) resistant cells in the presence of cetuximab. b Representative blot of total EGFR and IGF-1R show increased levels in cetuximab resistant cells relative to parental cells. c, d Quantitation of total EGFR and IGF-1R levels normalized to GAPDH from four independent experiments