Effect of anti-EGFR-targeted therapies on MDA-MB-231 cell migration and viability.

<p>(A) Cells were treated with 75 µg/mL cetuximab (cx), 10 µg/mL lapatinib (lp) or 10 µg/mL gefitinib (gf) and allowed to migrate through inserts (8 µm) under normoxia and hypoxia (1% O2) for 24 H. Cell migration is expressed as the percentage of unmigrated cells. Only gefitinib inhibited MDA-MB-231 cell migration under both conditions. (B) Cells were treated with increasing concentrations of cetuximab (C0:0, C1:25, C2:75, C3:100, C4:150 µg/mL), lapatinib and gefitinib (C0:0, C1:3, C2:10, C3:20, C4:40 µg/mL) under normoxic conditions. Viability was assessed using green calcein-AM labeling and fluorometry (ex: 490/em: 520 nm). Cetuximab and lapatinib did not affect cell viability, whereas gefitinib induced mortality in a dose-dependent manner. (C) A viability assay was performed in a 96-well plate by measuring drug effects under hypoxia in a CMV-GFP cell model that constitutively expressed EGFP. The fluorescence of each well was measured by fluorometry (ex: 488/em: 507 nm), and the signal intensity was proportional to the number of viable cells. Gefitinib strongly induced mortality. The results are representative of at least three independent experiments. Statistical significance was determined by unpaired t-test between treated cells and controls (* p<0.05).