Fig. 1
Establishment and characterization of cetuximab-MEKi-resistant (CM-RES) human colorectal cancer cell lines. a, sensitivity of parental and resistant cell clones to the combination of cetuximab and the MEK-inhibitor BAY-86-9766 (refametinib) at fixed ratio 1 μg/ml:1 μmol/L after 96-h treatment, evaluated for proliferation by MTT assay, as described in the Materials and Methods. All the results are average ± SD of 3 independent experiments, each done in triplicate. The table summarizes the values of the IC50 and the relative fold-change in resistant versus parental cell lines. *: p < 0.05. b, morphologic changes in resistant cell lines compared to parental cell lines. Magnification 200X, reference bar: 20 μm. c, western blot analysis of protein involved in epithelial-mesenchymal transition in baseline condition. d, Transwell migration assay at 48 h of parental cells compared to resistant clones. Bars indicate fold-change ± SD compared to parental control. Each assay was performed in triplicate. Magnification: 10X. ***: p < 0.001. e, Transwell matrigel invasion assay at 72 h of parental cells compared to resistant clones. Bars indicate fold-change ± SD compared to parental control. Each assay was performed in triplicate. Magnification: 10X. ***: p < 0.001