Emerging role of exosomes and exosomal microRNA in cancer: pathophysiology and clinical potential

Background Exosomes are extracellular nanometric vesicles used by cells to communicate with each other. They are responsible for many pathological conditions, including tumors by transferring regulatory biomolecules that impact target cell activity. Because of their high concentration in exosomes compared with parental cells and the rest of exosomal content, specificity to the cell of origin, and their well-organized sorting mechanism, microRNAs (miRNAs) are thought to be the most potent exosomes cargo and used by scientists to track exosomes and to detect cell activity changes and prognosis in cancer early. Purpose In this review, the results of studies examining the role of exosomes in cancer pathophysiology and their clinical potential are discussed in detail. Summary of the Findings Tumor-derived exosomes (TDEs) mediate the dynamic changes of cancer growth and invasion, including local microenvironment remodeling, distance metastasis, angiogenesis, and tumor-associated immunosuppression. They also contribute to hypoxia-induced tumor progression and cancer cell drug resistance. As a result of exosomes being present in all body fluids, it is possible to have early accessible and less-invasive diagnostic and prognostic measures by forming a table for each cancer type and its matched specific miRNAs. Under testing, available therapeutic uses of exosomes include interference of exosomes biogenesis, secretion, or uptake, and recruitment of exosomes as target-specific drug delivery vehicles, and immunostimulatory agents for both cancer patients and healthy population to avoid cancer development from the start. Conclusion These data suggest that exosomes and exosomal microRNA are directly related to cancer progression mechanisms, and could be used in cancer early diagnosis, prognosis, and therapy.