Effective Therapeutic Approach for Head and Neck Cancer by an Engineered Minibody Targeting the EGFR Receptor

Abstract

Cetuximab, a chimeric monoclonal antibody developed for targeting the Epidermal Growth Factor Receptor (EGFR), has been intensively used to treat cancer patients with metastatic colorectal cancer and head and neck cancer. Intact immunoglobulin G (IgG) antibody like cetuximab, however, has some limitations such as high production cost and low penetration rate from vasculature into solid tumor mass due to its large size. In attempt to overcome these limitations, we engineered cetuximab to create single chain variable fragments (scFv-CH3; Minibody) that were expressed in bacterial system. Among three engineered minibodies, we found that MI061 minibody, which is composed of the variable heavy (VH) and light (VL) region joined by an 18-residue peptide linker, displays higher solubility and better extraction properties from bacterial lysate. In addition, we validated that purified MI061 significantly interferes ligand binding to EGFR and blocks EGFR's phosphorylation. By using a protein microarray composed of 16,368 unique human proteins covering around 2,400 plasma membrane associated proteins such as receptors and channels, we also demonstrated that MI061 only recognizes the EGFR but not other proteins as compared with cetuximab. These results indicated that engineered MI061 retains both binding specificity and affinity of cetuximab for EGFR. Although it had relatively short half-life in serum, it was shown to be highly significant anti-tumor effect by inhibiting ERK pathway in A431 xenograft model. Taken together, our present study provides compelling evidence that engineered minibody is more effective and promising agent for in vivo targeting of solid tumors.

HIV Protease Inhibitors Sensitize Human Head and Neck Squamous Carcinoma Cells to Radiation by Activating Endoplasmic Reticulum Stress

“…Recent advances in the understanding of the molecular mechanisms of disease initiation and progression have led to the development of more specific therapies, such as Cetuximab, a monoclonal antibody against the epidermal growth factor receptor (EGFR). Cetuximab has been approved for combinational therapy with radiation in patients with unresectable HNSCC [ 6 ]. Overexpression of EGFR was often associated with a poor prognosis in HNSCC [ 7 ].…”

Anti-HIV Humoral Response Induced by Different Anti-Idiotype Antibody Formats: An In Silico and In Vivo Approach

“…The minibody format allows one to overcome some limitations inherent in monovalent antibody-derived molecules, such as the Fab and scFv formats. To design the minibody P1, we added a hinge region to the scFvs to obtain a flexible protein [ 18 ] and the CH3 portion of the constant region of a murine immunoglobulin (as P1). For the murine CH3 sequence, we used the MAK33 sequence, which guarantees the homodimerization of the protein produced in a prokaryotic system [ 19 ], increasing the functional affinity and avidity of this molecule.…”

Targeted therapy for head and neck cancer: signaling pathways and clinical studies

“…Cetuximab is the only FDA-approved EGFR-targeted therapy in HNSCC. [249][250][251] Many compounds targeting EGFR have been developed in preclinical models, with promising response and tolerability profiles. Referencing the current knowledge that multimodality treatment provides new hope for aggressive HNSCC, many studies have investigated the response of combination treatment regimens, either with conventional surgery, radiotherapy and cytotoxic chemotherapy, or in novel precision medicine targeted or immunotherapy combinatorial regimens.…”