Circulating Extracellular Vesicles for Early-disease Thernostics (CEVET)

There is a growing body of evidence showing that extracellular vesicles (EVs) play a critical role on pathological and physiological processes including inflammation, tumor growth and immune responses. Intensified research interest has been drawn to explore the potential medical applications of EVs, for instances as biomarkers for early disease diagnosis and monitoring since they contain ample disease related nucleic acids and proteins. EVs can be easily accessible from body fluids, such as blood, cerebral spinal fluid, saliva and urine; Among the EVs, exosomes (40-200 nm in size) are secreted after mutivesicular and subsequent membrane fusion. These small vesicles carry rich information of the biological functions including cell-cell communication, signaling, inflammation, tumor metastasis etc. However the understandings on exosome signal proteins and nucleic acids (in particular mRNA and microRNA) are still very limited due to the lack of accurate and fast isolation and purification of the exosomes of interest. Existing isolation and detection methods of exosomes are mainly based differential centrifugation, flow cytometry, dynamic light scattering, immunoblotting, and ELISA techniques. However, detection of EVs with high sensitivity still remains a great challenge. Highly sensitive, reliable and simple assays for exosome quantification and analysis will surely facilitate the mechanism studies of disease development.

Based on our rich experiences on developing sensors for biomarkers quantification, here we propose to develop a highly promising platform for direct, high-throughput expression profiling of circulating cancer-derived exosomes in body fluids. The detection is based on the specific immuno-interaction between the antibody probe and the surface proteins on the target disease-derived exosomes. The captured exosomes will be collected for further analysis including surface proteins profiling and miRNAs profiling for disease diagnosis; as well as drug responses for the therapeutics screening and development. Neither offline sample enrichment nor purification is required for such a sensitive and selective detection and analysis. As a proof-of-concept, urine samples and serum of prostate cancer (PCa) associated exosomes will be our focus. We anticipate the proposed assay will be rapid, simple, highly specific and sensitive. The assay will not only be useful for the isolation and detection of exosomes, but also readily feasible for analysis of other EVs, including microvesicles and apoptotic bodies. The success of the project would provide a tool for exosome extraction and novel insight for EV based molecular diagnosis, cancer signaling pathways and therapeutic opportunities of EVs.