A Bispecific Enediyne-Energized Fusion Protein Containing Ligand-Based and Antibody-Based Oligopeptides against Epidermal Growth Factor Receptor and Human Epidermal Growth Factor Receptor 2 Shows Potent Antitumor Activity

Abstract

Purpose: The cooverexpression of epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 (HER2) observed in many human tumors and their synergistic interaction in the transformation of cells make these receptors important targets for the development of new targeted therapeutics. Targeting of EGFR and HER2 simultaneously has been pursued as a strategy with which to potentially increase efficiency and selectivity in therapy of certain cancers. This study was set to construct a bispecific energized fusion protein (Ec-LDP-Hr-AE) consisting of two oligopeptides against EGFR and HER2, and lidamycin, and investigate its antitumor efficacy.Experimental Design: In vitro experiments measured the binding and internalization of bispecific Ec-LDP-Hr fusion protein. The potency of energized fusion proteins was also done in which the bispecific Ec-LDP-Hr-AE was compared with lidamycin (LDM) and its monospecific counterparts, Ec-LDP-AE and LDP-Hr-AE. In vivo, Ec-LDP-Hr-AE was given i.v. to nude mice bearing human ovarian carcinoma SK-OV-3 xenografts.Results: Binding and internalization studies showed that bispecific fusion protein Ec-LDP-Hr bound to carcinoma cells specifically and then were internalized into the cytoplasm. Bispecific Ec-LDP-Hr-AE was more potent and selective in its cytotoxicity against different carcinoma cell lines than corresponding momospecific agents and LDM in vitro. In addition, Ec-LDP-Hr-AE significantly inhibited the growth of SK-OV-3 xenografts in nude mouse model. In vivo imaging study showed that FITC-labeled Ec-LDP-Hr was targeted and accumulated in the tumors.Conclusion: A ligand-based and an antibody-based oligopeptide fused to the enediyne antibiotic LDM created a new bispecific fusion protein with low molecular weight and more potent in vitro and in vivo antitumor activity (than momospecific fusion proteins). Clin Cancer Res; 16(7); 2085-94. ©2010 AACR.The ErbB family (ErbB1/EGFR, ErbB2/HER2, ErbB3/ HER3, and ErbB4/HER4) of receptor tyrosine kinases is known to drive both formation and progression of several commonly occurring cancers (1). Ligand binding to the receptors results in receptor homodimerization and heterodimerization, then initiated a series of intracellular events that ultimately promote cell growth, proliferation, differentiation, and migration (2-4). Human epidermal growth factor receptor 2 (HER2) has no identified ligand but it is the preferred binding partner for the other three family members (5). The cooverexpression of epidermal growth factor receptor (EGFR) and HER2 observed in many human tumors and their synergistic interaction in the transformation of cells make these receptors important targets for the development of new targeted therapeutics (6-8). Several monoclonal antibodies (e.g., cetuximab, trastuzumab, and pertuzumab) and tyrosine kinase inhibitors (e.g., gefitinib, erlotinib, and lapatinib) targeting EGFR and HER2 or both have been approved by the U.S. Food and Drug Administration for therapeutic use and several more are in ...

Antitumor efficacy of the scFv-based fusion protein and its enediyne-energized analogue directed against epidermal growth factor receptor

“…Expression levels of EGFR in various cell lines were analyzed by western blot as described by Guo et al [14]. Immunofluorescence assay was applied to compare the binding activity of ER(Fv-LDP) to four cell lines that express EGFR at different levels.…”

Lidamycin inhibits tumor growth and pulmonary metastasis in murine breast carcinoma and shows synergy with paclitaxel

“…LDM (C1027) also showed antiangiogenesis and antimetastatic activity, preferentially targeting hypoxic cells [14]. In the previous study, it has been studied for cancer treatment, enhancement of its targeting, selectivity and efficiency, and drug combination therapy of certain cancers [33][34][35]. As reported, LDM induced unusual DNA double-strand breaks [36].…”

A ligand-based and enediyne-energized bispecific fusion protein targeting epidermal growth factor receptor and insulin-like growth factor-1 receptor shows potent antitumor efficacy against esophageal cancer

“…The fusion protein EGF-LDP-IGF, EGF-LDP and LDP-IGF were constructed, extracted and purified according to our previous approach (26). The enediyne-energized analogues of fusion proteins EGF-LDP-IGF-AE, EGF-LDP-AE and LDP-IGF-AE were generated after the active chromophore (AE) of LDM was assembled into fusion proteins.…”