Exosome-Encapsulated MicroRNAs As Potential Circulating Biomarkers In Colon Cancer

Colorectal cancer (CRC) is third leading cause of cancer related death worldwide. Despite advancesin detection of prognostic and diognostic biomarker, only a very small number of markers have beenlaunched. Recently microRNAs (miRNA) are emerged as a potential markers in different tumortypes, including CRC. Exosome-encapsulated microRNAs are being suggested as a new class novelbiomarkers as diagnostic and predictive markers in colorectal cancer. These particles are releasedfrom many cell types into the extracellular space upon fusion of multivesicular bodies (MVB) withthe plasma membrane. MVBs are in fact late endosomes that carry intraluminal endosomalvesicles. They contain a wide variety of information, including proteins, lipids, RNAs, nontranscribedRNAs, miRNAs, which can be circulated in various body fluids (e.g., blood, salvia,ascites, urine). Exosomes can be taken up by neighbouring or distant cells and thereby modulate thefunction of recipient cells and play a key role in disease progression or facilitate metastasis incancers. The aim of current review is to give an overview about origin and trafficking of exosomesbetween cells, techniques to isolate exosomal microRNAs as well as the potential applications ofexosome-encapsulated microRNAs as diagnostic markers in clinical settings in colorectal cancer.Therefore, exosomes may consider a house of disease-specific miRNA signature that can controlmany aspects of human physiological status and are therefore potentially provides a usefullinformation for prognosis of patients than other circulating miRNAs. There is growing body ofevidence showing the prognostic and diagnostic value of some exosomal miRNAs in colon cancer(e.g., miR-150, miR-21, miR-192, let-7a, miR-223, and miR-23a). These findings provide a novelinsight on novel application of these markers as novel non-invasive biomarkers for early detectionand risk assessment patients with colorectal cancer, although further investigations in largerpopulation are required to explore the clinical utility of exosomal miRNAs in CRC patients.