Exosomes have recently come into focus as “natural nanoparticles” for use as drug delivery vehicles. Researchers at the University of North Carolina at Chapel Hill set out to assess the feasibility of an exosome-based drug delivery platform for a potent chemotherapeutic agent, paclitaxel (PTX), to treat MDR cancer. Herein, they developed and compared different methods of loading exosomes released by macrophages with PTX (exoPTX), and characterized their size, stability, drug release, and in vitro antitumor efficacy. Reformation of the exosomal membrane upon sonication resulted in high loading efficiency and sustained drug release. Importantly, incorporation of PTX into exosomes increased cytotoxicity more than 50 times in drug resistant MDCKMDR1 (Pgp +) cells. Next, the studies demonstrated a nearly complete co-localization of airway-delivered exosomes with cancer cells in a model of murine Lewis Lung Carcinoma pulmonary metastases, and a potent anticancer effect in this mouse model. The researchers conclude that exoPTX holds significant potential for the delivery of various chemotherapeutics to treat drug resistant cancers.
Kim MS et al. (2015) Development of Exosome-encapsulated Paclitaxel to Overcome MDR in Cancer cells. Nanomedicine [Epub ahead of print]. [abstract]