Strengthened binding affinity of bispecific antibody nanoplatforms improved the anti-tumor efficacy

Dual receptor targeting (DRT) strategies use bispecific antibodies to simultaneously target two distinct disease mediators and thereby overcome major escape mechanisms evident in mono-targeted therapy. DRT enhances the binding affinity between the ligand and receptors and the specific targeted delivery of nanoparticles (NPs) into cancer cells. In this study we developed anti-EGFR cetuximab (CTX) and Herceptin (HER) decorated poly(lactic-co-glycolic acid) (PLGA) NPs for the targeted delivery of docetaxel (DTX), which we call DRT-DTX-PLGA-NPs, and we quantified their binding affinity with EGFR and HER2 positive cancer cells. The binding affinity assay indicated that dual conjugation of CTX and HER on PLGA-NPsenhanced the binding affinity between the NPs and cells additively in terms of affinity and synergistically in terms of adhesion energy, compared with PLGA-NPs conjugated with CTX and HER. Furthermore, the DRT-DTX-PLGA-NPs exhibited higher cellular uptake and higher cancer cell cytotoxicity than the single receptor-targeted NPs. In SW480 xenograft mice, the DRT-DTX-PLGA-NPs were more concentrated and retained at the tumor site due to their enhanced binding affinity, and as a result, tumor volume and tumor weight were significantly inhibited compared with tumors treated with the single-ligand targeted NPs. Therefore, DRT-NPs have the potential to improve cancer therapy by providing high affinity between NPs and cells and improving selectivity compared with single-ligand-targeted NPs.