Characterization of Interactions Between Taspine Derivate TPD7 and EGF Receptor by Cell Membrane Chromatography with Zonal Elution and Frontal Analysis

In this study, a high epidermal growth factor receptor (EGFR) expression cell membrane chromatography method was established to investigate the interactions between ligands and EGFR. The affinity of ligands for EGFR was evaluated by frontal analysis. Competition study using afatinib as the marker was used to evaluate the interactions that occurred at specific binding sites on EGFR. The results indicated that TPD7, HMQ1611 and afatinib may have direct competition at a single common binding site on EGFR. From the model of frontal analysis, the dissociation equilibrium constants (K_D) were 6.05 × 10⁻⁷ M for afatinib, 6.91 × 10⁻⁷ M for TPD7, and 9.68 × 10⁻⁷ M for HMQ1611. In cells, HMQ1611 and TPD7 could both inhibit the growth of HEK293/EGFR cells and significantly decrease EGFR phosphorylation in HEK293/EGFR cells in a dose-dependent manner. The studies showed that TPD7 and HMQ1611 could bind EGFR as afatinib. TPD7 exhibited higher inhibitory effect than HMQ1611 while TPD7 and HMQ1611 had a similar effect in HEK293/EGFR cells, thus indicating that TPD7 might be the novel blocker for cancer with high-EGFR expression.