EGFR-targeting, β-defensin-tailored fusion protein exhibits high therapeutic efficacy against EGFR-expressed human carcinoma via mitochondria-mediated apoptosis

摘要

Defensins play an essential role in innate immunity.In this study,a novel recombinant β-defensin that targets the epidermal growth factor receptor (EGFR) was designed and prepared.The EGFR-targeting β-defensin consists of an EGF-derived oligopeptide (Ec),a β-defensin-1 peptide (hBD1) and a lidamycin-derived apoprotein (LDP),which serves as the "scaffold" for the fusion protein (Ec-LDP-hBD1).Ec-LDP-hBD1 effectively bound to EGFR highly expressed human epidermoid carcinoma A431 cells.The cytotoxicity of Ec-LDP-hBD1 to EGFR highly expressed A431 cells was more potent than that to EGFR low-expressed human lung carcinoma A549 and H460 cells (the IC50 values in A431,A549,and H460 cells were 1.8 + 0.55,11.9 + 0.51,and 5.19 + 1.21 μmol/L,respectively);in addition,the cytotoxicity of Ec-LDP-hBD1 was much stronger than that of Ec-LDP and hBD1.Moreover,Ec-LDP-hBD1 suppressed cancer cell proliferation and induced mitochondria-mediated apoptosis.Its in vivo anticancer action was evaluated in athymic mice with A431 and H460 xenografts.The mice were administered Ec-LDP-hBD1 (5,10 mg/kg,i.v.) two times with a weekly interval.Administration of Ec-LDP-hBD1 markedly inhibited the tumor growth without significant body weight changes.The in vivo imaging further revealed that Ec-LDP-hBD1 had a tumor-specific distribution with a clear image of localization.The results demonstrate that the novel recombinant EGFR-targeting β-defensin Ec-LDP-hBD1 displays both selectivity and enhanced cytotoxicity against relevant cancer cells by inducing mitochondria-mediated apoptosis and exhibits high therapeutic efficacy against the EGFR-expressed carcinoma xenograft.This novel format of β-defensin,which induces mitochondrial-mediated apoptosis,may play an active role in EGFR-targeting cancer therapy.