Figure 3.

HER-3 peptide mimics inhibit phosphorylation of HER-3 positive cancer cell lines (MDA-MB-468). Cancer cells were treated for 1 h prior to ligand stimulation with 10 ng/mL HRG for 15 min. After treatment, cells were lysed 1X in RIPA lysis buffer (Santa Cruz) and phosphorylated HER-3 was measured via a phosphor-HER-3 ELISA kit from R+D Systems (A). Percent inhibition was calculated by taking absorbance (abs) readings at 450 nm and using the following equation: (abs. untreated-abs. treated)/abs. untreated × 100. Results displayed are representative of two independent experiments with duplicate samples. Error bars represent SD of the mean. To confirm ELISA results, cell lysates were also subjected to western blotting. Lysates were solved in SDS-PAGE, transferred to PVDF membrane and probed for expression of pHER-3with a commercial phosphor-tyr-HER-3 antibody from cell signaling (B). Results displayed are representative of two independent experiments (n = 2). In all experiments, an irrelevant peptide was used as a negative control.