Abstract P171: Ligand-displaying-exosomes using RNA nanotechnology for targeted delivery of multispecific drugs for liver cancer regression

Liver cancer such as hepatocellular carcinoma (HCC) poorly responds to chemotherapeutics as there are no effective means to deliver drugs to liver cancer due to the intrinsic drug effluxion and detoxification properties of the liver. Exosomes are extracellular vesicles that deliver payload via a fusion mechanism to cell cytosol without endosome trapping. Here we report the use of GalNAc as ligands to decorate exosomes that loaded with anticancer therapeutics Paclitaxel (PTX) and miR122 that silence both the drug efflux pump MDR1 (multidrug-resistant protein-1) and the oncogenic gene ADAM10 (A Disintegrin and metalloproteinase domain-containing protein 10). GalNAc is the ligand that provides exosome targeting ability to bind the hepatocyte surface receptor ASGP-R (asialoglycoprotein-receptor) usually express on liver cancer cell surface abundantly. PTX is highly hydrophobic, when it is conjugated to a polymeric hydrophilic RNA as a prodrug, its water solubility increases 32000-fold. No toxicity was detected. The PTX conjugated RNA strands assembled into a 4-way junction RNA nanoparticle to harbor 24-copies of PTX and 1-copy of miR122. The 4WJ RNA nanoparticles are loaded into the exosome and are decorated with GalNAc as a targeting ligand using RNA nanotechnology. Binding studies demonstrated that the multispecific exosome selectively binds and internalizes into the HepG2 liver cancer cells, and delivers the PTX and miR122 into the cell cytosol, exhibiting the highest efficacy in killing the targeted cancer cells due to the multispecific effect comes from miR122, PTX, GalNAc, and Exos. The liver cancer tumor regressed significantly after systemic injection of the multispecific exosomes to mice xenograft-bearing liver cancer. The results demonstrate that exosomes can serve as a multivalent vector to carry ligands, RNAi, and chemical drugs as a multispecific strategy to treat incurable liver cancers.Citation Format: Xin Li, Satheesh Ellipilli, Hongzhi Wang, Wen-Jui Lee, Yuan Soon Ho, Peixuan Guo. Ligand-displaying-exosomes using RNA nanotechnology for targeted delivery of multispecific drugs for liver cancer regression [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr P171.