Loading And Molecular Labeling Of Cell-Specific Exosomes By Hdl-Like Aunps

Proceedings: AACR 106th Annual Meeting 2015; April 18-22, 2015; Philadelphia, PAExosomes are 30-100 nm diameter lipid vesicles produced by most cells. Exosomes carry diverse cargo, such as RNA and proteins. Cancer cells produce an abundant amount of exosomes, which are released from cells of the primary tumor into the tumor microenvironment and the circulation. Data show that exosomes can promote cancer progression and metastasis by delivering, for instance, pro-metastatic factors to pre-metastatic sites. It is not currently possible to specifically separate tumor-derived exosomes from complex matrices. This ability would provide a better understanding of their contribution to tumorigenesis and cancer progression. Furthermore, the targeting properties of exosomes make them appealing vehicles for encapsulating and delivering therapeutic cargo. However, it is challenging to isolate and then load exosomes with specific drugs. Uniquely, our data reveal that synthetic high-density lipoprotein nanoparticles (HDL NPs) can be tailored to achieve cell-specific exosome labeling and loading of therapeutic cargo. HDL NPs are synthesized using a 5 nm diameter spherical gold nanoparticle. The gold NP serves as a template to control size and shape. Apolipoprotein A-I and phospholipids are conjugated to the gold surface, yielding a synthetic HDL NP similar in size, shape, surface chemistry, and function to some natural HDLs. Our data demonstrate that, upon addition of HDL NPs to cultured CWR 22Rv1 prostate cancer cells, they are packaged into exosomes that are secreted from these cells. Furthermore, HDL NPs made using phospholipids functionalized with either biotin or fluorophore molecules leads to the incorporation of the phospholipids into the exosomes. Thus, the specific cell-derived exosomes are labeled with gold, a molecular fluorophore label, and/or biotin. In each case, the specific exosomes are easy to isolate using methods such as fluorescent isolation or by the robust streptavidin-biotin interaction. Isolated exosomes retain the same size and molecular markers as exosomes from untreated cells. Overall, this unique method may provide control over exosomes for a myriad of diagnostic and therapeutic uses.Citation Format: Nicholas L. Angeloni, Kaylin M. McMahon, C. Shad Thaxton. Loading and molecular labeling of cell-specific exosomes by HDL-like AuNPs. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3671. doi:10.1158/1538-7445.AM2015-3671