A, Antiproliferative activities of eCF506, dasatinib, bosutinib, and saracatinib across 16 breast cancer cell lines. Calculated GI50 values are ranked by sensitivity to eCF506. Error bars, ±SD (n = 3). B, Cell-cycle analysis after treating MDA-MB-231 and MCF7 cells with eCF506 or dasatinib for 48 hours. Error bars, ± SD (n = 3). Changes in G1 phase compared by one-way ANOVA (Dunnett correction for multiple comparison); *, P < 0.05; ****, P < 0.0001; ns, nonsignificant. C, Representative Western blots after treating MDA-MB-231 for 3 and 24 hours with eCF506, dasatinib, bosutinib, and saracatinib. Plots of normalized SRC-pY419 levels after each treatment are shown at the bottom. Error bars, ±SD (n = 3). D, Analysis of total and phosphorylated FAK from the RPPA study in MCF7 (top) and MDA-MB-231 (bottom) cells after 3 hours (left) and 24 hours (right) treatment with eCF506 and dasatinib at 0.3 to 300 nmol/L. Arrows, FAK-pY397.