Tumor-derived exosomes in metastasis signaling and implications

Abstract

Genome-wide studies for decoding molecular mechanisms of tumor cell-host interactions associated with cancer progression have revealed a determinant role for exosome-mediated intercellular communications in metastasis signaling. Exosomes are specialized plasma membrane-bound nanovesicles secreted under physiological conditions by various cells to regulate tissue homeostasis and immune response. In cancer, overproduction of exosomes and/or changes in their contents are common features of many cancer cell types and can bear unique molecular signatures reminiscent to the cancer phenotype. Exosomes mediate paracrine signaling required for cross-talks between tumor cells and the host stromal and infiltrating inflammatory and immune cells within the tumor tissue microenvironment as well as distant metastatic niches. Exosomes promote cancer invasiveness at multiple levels of the metastatic cascades favoring a permissive environment for cell survival and growth. This review focuses specifically on the implication of cancer-associated exosomes for cell signaling that promotes metastasis development. For detailed biochemical and molecular studies addressing exosome biology, we refer the reader to selected seminal studies in the field.