Figure 1.

Upregulation of AXL confers acquired resistance to erlotinib in HCC827-ER3 cells. (A) HCC827 and HCC827-ER3 cells were treated with indicated concentrations of erlotinib for 72 hours and viability was measured by MTS cell viability assay. Results are from three independent experiments and are expressed as percent viability of vehicle-treated cells. Data are shown as the mean ± SD. (B) Cells were treated with or without indicated dose of erlotinib for 6 hours, after which cell lysates were prepared and subjected to immunoblot analysis with antibodies to phosphorylated (p) or total forms of AXL, EGFR and GAPDH (loading control). EGFR, epidermal growth factor receptor.