Exosomes: New players in cancer

Abstract

The past decade has witnessed an exponential increase in research on exosomes. For many years considered to be extracellular debris, exosomes are now considered important mediators in intercellular communication. The capability of exosomes to transfer proteins, DNA, mRNA, as well as non-coding RNAs has made them an attractive focus of research into the pathogenesis of different diseases, including cancer. Increasing evidence suggests that tumor cells release a large sum of exosomes, which may not only influence proximal tumor cells and stromal cells in local microenvironment, but also can exert systemic effects when participating in blood circulation. In this study, we review the current understanding on this topic. The literature outlines two broad facets of exosomes in cancer: 1) promotion of tumor growth, tumorigenesis, tumor angiogenesis, tumor immune escape, drug resistance, and metastasis and 2) their role as promising biomarkers for cancer diagnosis and even as potential treatment targets for cancer patients.

Exosomes for Non‐Invasive Cancer Monitoring

“…We feel that this technique has the potential to be employed to analyze exosomes derived from different cancers. Once developed, this method should enable early diagnosis of specific cancers in the absence of any prior knowledge about biomarkers . Consequently, the diagnostic and prognostic value of exosomes will be enhanced (Figure ).…”

Roles of microRNAs in mammalian reproduction: from the commitment of germ cells to peri‐implantation embryos

“…Exosomes and cell‐membrane‐derived micro‐ and nano‐vesicles could be the main medium for this embryo–maternal crosstalk (Diehl et al, ; Saadeldin et al, ), however, miRNAs could also be carried through the circulatory system by apoptotic bodies, RNA‐binding lipoproteins and Argonaute protein complex (Ling, Bao‐feng, & Jing, ; Sohel, ). These circulating miRNAs originating from one cell or organ could be transported to and absorbed by neighbouring or distant cells, for example, miRNAs originating from tumour cells could be absorbed by other healthy cells leading to their transformation to malignancy (Guo et al, ). Thus, it could be assumed that each cell of the embryonic ICM randomly absorbs different maternal miRNAs delivered through the circulatory system; this variation in miRNA intake among the cells of the embryonic ICM may lead the cells towards different lineages.…”

Exosomes in Prostate Cancer Diagnosis, Prognosis and Therapy

“…Those naturally occurring membrane particles mediate intercellular communication by delivering molecular information between cancer and stromal cells, especially cancer-associated fibroblast (CAFs) [14]. Cancer cell-derived EVs cause very diverse effects and may depend on their target cells, which appear to take them up in several ways, such as receptor/lipid raft endocytosis, phagocytosis, micropinocytosis or fusion with the plasma membrane [17]. Some exosomes can reduce the anti-cancer immune response, interact with specific membrane receptors [9] and promote a suitable microenvironment, while others may cause drug resistance and the failure of antibody therapy involving RNA species and protein delivery [21].…”