Abstract 3030: An exosome isolation system for serum-based cancer biomarker discovery

Abstract Exosomes are 40-100 nm membrane vesicles secreted by most cell types, including all cancer cells. While the exact biological functions of exosomes remain unclear, exosomes can mediate communication between cells, facilitating processes such as antigen presentation and in trans signaling to neighboring cells. The abundance of exosomes present in the circulation of cancer patients increases with tumor grade. Studies identifying protein and microRNA biomarkers in these circulating exosomes can reveal the tumor type and origin. These recent studies highlight the growing use and need of standardized exosome enrichment. What is missing in this research area is a method for simple, rapid and reproducible exosome purification to facilitate research into the role of exosome in both physiological and pathological process, as well as possible diagnostic and therapeutic potentials. In this study, SBI utilizes proprietary polymer mixture (ExoQuick) to precipitate exosome from human serum samples. Using ExoQuick, we successfully observe small RNAs in the exosome pellets and detect microRNAs by qPCR. Exosome precipitation from serum samples was verified using Western blot analysis on the ExoQuick supernatant and pellet fractions and probed with antibodies against two commonly found exosome biomarker proteins, CD63 and CD9. Robust signals for CD63 and for CD9 were observed only in the exosome pellet fractions but not in the serum supernatant. These preliminary data provide proof-of-concept for our approach in using polymer-based, one-step exosome purification method from human serum samples. The technologies developed in this study will advance the exosome research field by providing a simple and standardized exosome isolation method that will allow high-throughput exosome analysis to enable major strides forward in serum-based microRNA biomarker discoveries for cancer diagnostics and prognostics tools. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3030.