Fig. 2.

EpCAM targeting increases the potency of MM-131. (A) Computational simulation comparing the potency of MM-131 with that of huOA-5D5. For each level of Met expression (x axis) and EpCAM expression (y axis), the IC₉₀ for inhibition of Akt phosphorylation was calculated at 10 min following HGF stimulation. The values in the heat map indicate the fold change between MM-131 and huOA-5D5 (values >1 indicate that MM-131 is favorable). Dots represent a panel of cell lines with different cell surface levels of Met and EpCAM measured by quantitative fluorescence-activated cell sorting. (B) Testing model predictions in cell lines with low and high ratios of EpCAM/Met (0.33 for A549 and 28.9 for NCI-H747). (C) Testing model predictions in an isogenic cell line in which EpCAM was stably knocked down by RNAi. The EpCAM/Met ratio in NCI-H747 shEpCAM is 1.74. Antibodies were incubated with the indicated cell lines for 2 h before 10 min of stimulation with 1 nM HGF. Lysates were analyzed by pAkt ELISA; the dotted lines indicate the pAkt level in the absence of HGF and antibodies (media control). Plots in B and C reflect mean (n = 4) and SEM.