Specific inhibition of EGFR by AG1478 or IGF-1R by AG1024. (a-b) Under basal growth conditions, whole-cell extracts obtained from MDA-MB-468 and MCF-7 cells were analyzed for EGFR (a) and IGF-1R (b) expressions. (c-d) Cellular viability was measured by MTT assay. MDA-MB-468 and MCF-7 cells were treated with the indicated concentrations of AG1478 (c) (Students’ t-test, p = 0.022 at concentration of 50 μM) or AG1024 (d) for 48 h. (e-f) MDA-MB-468 cells were treated with 10 μM AG1478 or 10 μM AG1024 for 24 h. Western blot analysis was done on MDA-MB-468 cell lysates using antibodies specific for IGF-1R, p-IGF-1R (e) and EGFR, p-EGFR (f). * p < 0.05, MDA-MB-468 cells vs. MCF-7 cells.