Abstract

In situ Detection of Exosomal Biomarkers for Cancer Diagnosis

Won Jong Rhee, Associate professor, Division of Bioengineering, Incheon National University

Exosomes are small extracellular vesicles that contain biomolecules produced from their originating cells and known to travel through the circulatory system. They are biomarker reservoirs that provide disease information with a high accuracy, especially when specific markers, including miRNAs and proteins, are combined. Since the tumor is extremely heterogeneous, a single biomarker cannot reflect the exact symptoms of the disease or its stage. These make exosomal biomarkers from the body fluids attractive biomarkers that can lead to a paradigm shift in the diagnosis of disease including cancer. However, currently available exosomal miRNA and protein detection methods are time consuming, expensive, and laborious. Meanwhile, simultaneous detection of an exosomal miRNA and protein in a single reaction is even more challenging. Thus, the development of an efficient method for detecting multiple miRNAs and proteins in a single exosomal reaction is highly needed. Herein, to increase the value of using exosomes over other circulating biomarkers for cancer liquid biopsy, a method for simultaneous multiplexed in situ detection of exosomal miRNAs and proteins was developed. Exosomal miRNAs and surface proteins were simultaneously detected in captured exosomes with a high specificity, using nano-sized molecular beacons and fluorescent dye-conjugated antibodies. The method allowed the quantitative analysis of various disease-specific miRNAs and surface proteins in cancer cell line-derived exosomes in a single exosomal reaction. Overall, simultaneous multiplexed in situ detection of exosomal miRNAs and surface proteins can be developed as a simple, cost-effective, non-invasive liquid biopsy method for diagnosing cancer.