Anti-Proliferative Effect of Specific Anti-EGFR Single Chain Antibody on Triple Negative Breast Cancer Cells

Background: Targeted therapy is an important treatment strategy that is widely used for cancer therapy. Epidermal growth factor receptor (EGFR) is overexpressed in a significant percentage of Triple-negative breast cancer (TNBC) patients. Although Cetuximab, which targets EGFR, has shown some inhibitory effects on TNBC cells, Cetuximab resistance cases due to ligand-independent activating mutations in the EGFR gene limit its application. Due to various benefits of single chain antibodies (scFvs), the use of these antibodies in cancer targeted therapy is increasing. In this study, a specific anti-EGFR antibody was isolated and evaluated. Methods: Panning procedure was used against an immunodominant epitope of EGFR in its dimerization arm using a diverse phage library. Polymerase Chain Reaction (PCR) and fingerprinting were applied to identify the specific clones. The MTT tetrazolium assay was performed to evaluate the inhibitory effects of selected anti-EGFR scFv phage antibody on MDA-MB-468, a TNBC cell line. Results: After four round of panning, one dominant pattern was observed in DNA fingerprinting with frequency of 85%. The growth of MDA-MB-468 cells was decreased dose-dependently after treatment with anti-EGFR scFv phage antibody. No significant inhibitory effect of M13KO7 helper phage as negative control on the cell growth of MDA-MB-468 was observed (p> 0.05). Conclusions:The selected anti-EGFR scFv with high anti proliferative effect on TNBC cells offers an effective alternative for TNBC targeted therapy. The antibody, which binds to the dimerization arm of EGFR and inhibits EGFR dimerization, could also overcome TNBC cases with Cetuximab resistance due to ligand-independent activating mutations.