ECM-detachment sensitizes ErbB2-overexpressing cells to EGFR therapy.
A, 10:ErbB2 cells were treated with indicated concentrations of AG1478, and caspase activation was measured at 48 h of ECM-attachment or detachment (top). EGFR inhibition was confirmed by immunoblot for phospho-EGFR (Y1173) and β-actin (loading control) (bottom). a.u. is defined as fold change over DMSO. B, 10:ErbB2 cells were treated with indicated concentrations of gefitinib, and caspase activation was measured at 48 h in ECM-attachment or detachment (top). EGFR inhibition was confirmed by immunoblot for phospho-EGFR (Y1173) and β-actin (loading control) (bottom). a.u. is defined as fold change over DMSO. All error bars represent S.D., and p values were determined using a two-tailed Student's t test.