Fig. 1

Establishing mitogen activated protein kinase inhibitor-resistant melanoma models. a A mitogen activated protein kinase BRAF inhibitor-resistant (BRAFi-R) model was established using SK-MEL-28 and A375 malignant melanoma cell lines. Schedule of administered concentrations of mitogen activated kinase inhibitor, vemurafenib. b Phase contrast images of control SK-MEL-28 parental melanoma cell lines and (c) BRAF inhibitor-resistant SK-MEL-28-BRAFi-R melanoma cell line 1. Black bar indicates 1.0 μm. White arrows in image of resistant cell lines point to cellular structures typical for differentiated melanocytes. d and e Cell viability assay on melanoma cell lines at 10 μM vemurafenib. Absorption in XTT assay is measured at 570 nm. White squares indicate control melanoma cell lines, red triangles and diamonds show melanoma BRAFi-R model. f IC50 concentrations of vemurafenib of control and drug-resistant cancer cell lines