Covalent Conjugation of Extracellular Vesicles with Peptides and Nanobodies for Specific Delivery of Anticancer Drugs


Student thesis: Doctoral Thesis

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Award date2 Sep 2020


Delivery vehicles are required for anticancer hydrophobic drugs and RNA therapeutics because these molecules are not able to penetrate cancer cells. Nanoparticles are commonly used drug delivery systems to improve drug effects. However, most of the nano delivery systems rise some safety concerns, urging the search for alternative vehicles. Extracellular vesicles (EVs) are the most promising candidate for drug carriers due to their remarkable biocompatibility as natural carriers of bioactive molecules. Their therapeutic potential can be further improved by conjugation with targeting ligands, thereby allowing antigen-specific targeting. However, existing methods to engineer target specific EVs are tedious and inefficient. Here, we describe a new method for covalent conjugation of EVs with specific peptides or nanobodies using protein ligases. OaEAP1 ligase is particularly efficient and consistent, with the ability to conjugate more than 380 copies of peptides to each EV. The ligase can also conjugate various nanobodies to EVs in a two-step ligation mediated by a linker peptide. Conjugation with either the EGFR-targeting peptide or anti-EGFR nanobody facilitates the accumulation of EVs in EGFR-positive lung cancer cells, both in vitro and in vivo. EGFR-targeted delivery of paclitaxel (PTX) at a low dose using RBCEVs suppresses the tumor growth significantly by increasing the efficacy and solubility of PTX in a xenografted mouse model of EGFR-positive lung cancer. The method is a simple, yet efficient and gentle method for the stable surface modification of EVs that bypasses the need for genetic alterations, thereby avoiding the risk of oncogenesis.

    Research areas

  • Extracellular vesicles, drug delivery system, red blood cell, OaEAP1 ligase, EGFR-targeted delivery, peptide, nanobody, paclitaxel, mRNA, lung cancer