Figure 1.

Development and characterisation of TKI-R CALU-3 cancer cells. (A) Inhibitory concentration 50 values (IC₅₀) for treatment with erlotinib, gefitinib, vandetanib or sorafenib in parental human lung adenocarcinoma CALU-3 cells (P) and in their TKI-R derivatives (ERL-R, GEF-R, VAN-R and SOR-R). Cell proliferation was measured with the MTT assay. The drug concentrations required to inhibit cell growth by 50% (IC₅₀) were determined by interpolation from the dose-response curves. Results represent the average of three separate experiments each performed in quadruplicate. (B) Western blotting analysis of selected growth factor receptors (EGFR, IGF-1R and MET) and of down-stream signalling pathways in parental human lung adenocarcinoma CALU-3 cells (P) and in their TKI-R derivatives (ERL-R, GEF-R, VAN-R and SOR-R). β-Actin was included as a loading control.