Urinary Exosomes: The Potential for Biomarker Utility, Intercellular Signaling and Therapeutics in Urological Malignancy.

PURPOSE: Exosomes are small secreted vesicles that contain proteins, mRNA and miRNA with the potential to alter signaling pathways in recipient cells. While exosome research has flourished, few publications have specifically considered the role of genitourinary cancer shed exosomes in urine, their implication in disease progression and their usefulness as noninvasive biomarkers. In this review we examined the current literature on the role of exosomes in intercellular communication and as biomarkers, and their potential as delivery vehicles for therapeutic applications in bladder, prostate and renal cancer.
MATERIALS AND METHODS: We searched PubMed® and Google® with the key words prostate cancer, bladder cancer, kidney cancer, exosomes, microvesicles and urine. Relevant articles, including original research studies and reviews, were selected based on contents. A review of this literature was generated.
RESULTS: Cancer exosomes can be isolated from urine using various techniques. Cancer cells have been found to secrete more exosomes than normal cells. These exosomes have a role in cellular communication by interacting with and depositing their cargo in target cells. Bladder, prostate and renal cancer exosomes have been shown to enhance migration, invasion and angiogenesis. These exosomes have also been shown to increase proliferation, confer drug resistance and promote immune evasion.
CONCLUSIONS: Urinary exosomes can be isolated from bladder, kidney and prostate cancer. They serve as a potential reservoir for biomarker identification. Exosomes also have potential for therapeutics as siRNA or pharmacological agents can be loaded into exosomes.