Abstract 5407: Milk derived exosomes: Scalable source of biologically active drug delivery nanoparticles

Abstract

Abstract Exosomes are biological nanoparticles and found in almost all the body fluids. They shuttle in and out of cells, are comprised of lipid bilayers, and carry a cargo of macromolecules. Because of the nano size (30-100 nm) these natural vesicles are being explored as nanodevices for the development of new therapeutic applications. Here we show bovine milk as a scalable source of exosomes and as a drug delivery vehicle for small molecules - both lipophilic and hydrophilic. The exosomes were isolated by differential centrifugation with the size generally ranging from 30-100 nm as analyzed by NanoSight and confirmed by electron microscopy and atomic force microscopy. The identity of exosomes was confirmed by surface protein markers (CD63, CD81), buoyant floatation density (1.12 g/ml) determined by sucrose density gradient, and high content of immune-related miRNAs and mRNA as determined by PCR. Exosomes, suspended in PBS, and stored frozen (-80°C) were found to be stable in terms of their size and biological activities. Milk exosomes loaded with fluorescent dye were readily taken up by macrophages and human cancer cells in vitro and distributed in the various tissues of nude mice following treatment with gavage and i.v. routes. Imaging of various tissues collected after euthanasia showed a broad tissue distribution of the exosomes delivered via the oral route, whereas exosome concentration predominated in the liver when administered by the i.v. route. Both lipophilic and hydrophilic chemopreventive (curcumin, withaferin A, anthocyanidins, and punicalagins, etc.) and chemotherapeutic (paclitaxel and docetaxel) agents could be loaded onto exosomes with 8%-60% drug load with respect to exosomal protein content. Drug-exosomal formulations showed significantly higher antiproliferative activity against lung, breast and ovarian cancer cells versus the free drugs. The drug formulation also showed significantly higher tissue drug levels, and enhanced anti-inflammatory and antitumor activity versus the free drug. Intriguingly, in the absence of any drug, the milk exosomes showed anti-proliferative and anti-inflammatory activities in cancer cells, suggesting the presence of protective factors in the milk exosomes (e.g., miRNAs); this notion corroborates the epidemiological and experimental findings of the presence of built-in immune factors in milk. (Supported from USPHS grants CA-118114 and CA-125152, Kentucky Lung Cancer Research Program, Agnes Brown Duggan Endowment, and Helmsley Funds). Citation Format: Farrukh Aqil, Radha Munagala, Jeyaprakash Jeyabalan, Ramesh C. Gupta. Milk derived exosomes: Scalable source of biologically active drug delivery nanoparticles. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5407. doi:10.1158/1538-7445.AM2014-5407