Figure 11.

HER-3 vaccine antibodies produce synergistic antitumor effects when used in combination with HER-1 vaccine antibodies. Cancer cells (JIMT-1, BXPC3 and MDA-MB-468) were treated for 1 h with either HER-3 461 vaccine antibodies, HER-1 418 vaccine antibodies or combination of antibodies prior to ligand stimulation with both EGF and HRG (50 ng/mL). Cells were analyzed for proliferation via MTT inhibition assay as described above (A) and inhibition of phosphorylation of both HER-3 (B) and HER-1 (C) via ELISA kits from R+D Systems as described above. In all experiments, normal rabbit IgG (Pierce) was used as a negative control, and Cetuximab was used as a positive control. Results display averages of two independent experiments with triplicate samples (n = 3). Error bars represent SD of the average. In both assays, combination treatment HER-1 and HER-3 vaccine antibodies showed a better significant effect (**p < 0.02 for proliferation and HER-1 phosphorylation and **p < 0.03 for HER-3 phosphorylation respectively) while single treatment with the HER-1 and HER-3 inhibitors showed a lesser significant value (*p < 0.05) or was not significant in some of the cell lines.