Abstract 372: Biodistribution and tumor targeting of exosomes using mouse models
Authors: Moholkar Disha Nagesh , Kandimalla Raghuram , Aqil Farrukh , Gupta Ramesh 
Published: June 2022

Abstract
Biodistribution studies are relevant models for understanding the fundamental preclinical information of the distribution of drugs to the potential target organs, which provide insight on which on-target or off-target effects might be expected. One of our research focuses is the study of uptake and distribution of bovine milk- and colostrum-derived exosomes, functionalized exosomes and exosomes in polyethyleneimine (PEI) matrix (EPM) using near-infrared fluorescent dye in rodents. Previously, when DiR dye was loaded onto milk exosomes, biodistribution studies showed that route of administration had a significant influence on the tissue distribution with somewhat uniform biodistribution with oral gavage while predominated liver accumulation with the i.v. route. In this study, we show biodistribution of colostrum exosomes, EPM and tumor targeting by attaching tumor targeting ligand, folic acid (FA). We studied the biodistribution of these formulations using exosomes labeled with Alexa Fluor 750 (AF750) in wild-type mice and subcutaneous lung tumor-bearing mice. In various studies we tested: i) biodistribution of exosomes vs EPM, ii) effect of different administration routes such as intravenous (i.v.), oral (p.o.), subcutaneous (s.c.), intranasal (i.n.) and intramuscular (i.m.) on biodistribution, and iii) tumor targeting using FA-functionalized exosomes and EPM. Uniform tissue distribution was observed upon oral administration of exosomes while predominant hepatic accumulation was observed with i.v. administration. The i.n. route resulted in pre-dominant accumulation in lung, whereas i.m. and s.c. delivery had almost similar distribution as observed with i.v. route. The distribution of exosomes and EPM matrix was largely similar. We observed that the fluorescent signals from AF750-labeled FA-Exo and FA-EPM treatment revealed higher tumor accumulation of exosomes as compared to non-functionalized exosomes and EPM, respectively due to overexpression of folate receptors. Time-dependent distribution showed accumulation of EPM in tumors at later time point. The EPM formulations could be detected at the sites otherwise difficult to target such as brain and lymph nodes after systemic administration, thus indicating suitability of these formulations to cross physiological barriers. To validate the therapeutic potential, FA-EPM was loaded with 15 μg siKRAS and injected intravenously to orthotopic A549 lung tumor-bearing mice. Significant reduction in tumor volume (67%; p &lt;0.001) and tumor weight (76%; p &lt;0.001) was observed which corroborated the significant knockdown of KRAS protein (p &lt;0.01). Thus, this novel approach can be used as a nano ‘platform’ for drug delivery due to its increased circulating half-life, high uptake by target cells, and ability to load a diverse range of pharmaceutical therapeutics including biologics such as siRNA. (Supported from Duggan Endowment and 3P biotechnologies, Inc.)
Citation Format: Disha Nagesh Moholkar, Raghuram Kandimalla, Farrukh Aqil, Ramesh Gupta. Biodistribution and tumor targeting of exosomes using mouse models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 372.