Prostate cancer exosomes as modulators of the tumor microenvironment

Abstract

Researchers are currently trying to understand why some men with prostate cancer go on to develop aggressive disease whilst others maintain slow growing tumors. Although endogenous genetic anomalies within the tumor cell are important, the prevailing view is that the tissue microenvironment as a whole is the determinant factor. Many studies have focussed on the role of soluble factors in modulating the nature of the tumor microenvironment. There is however a growing interest in the role of extracellular vesicles, including exosomes, as regulators of disease progression. A variety of resident cells, as well as infiltrating cells, all contribute to a heterogeneous population of exosomes within the tumor microenvironment. Studies focussing on the role of exosomes in prostate cancer are however relatively rare. In this review, evidence from various cancers, including prostate, is used to present numerous potential roles of exosomes in prostate cancer. Whilst further validation of some functions may remain necessary it is clear that exosomes play a major role in intercellular communication between various cell types within the tumor microenvironment and are necessary for driving disease progression.