Exosomes in tumor microenvironment: novel transporters and biomarkers

Abstract

Tumor microenvironment (TME) plays an integral part in the biology of cancer, participating in tumor initiation, progression, and response to therapy. Exosome is an important part of TME. Exosomes are small vesicles formed in vesicular bodies with a diameter of 30–100 nm and a classic “cup” or “dish” morphology. They can contain microRNAs, mRNAs, DNA fragments and proteins, which are shuttled from a donor cell to recipient cells. Exosomes secreted from tumor cells are called tumor-derived (TD) exosomes. There is emerging evidence that TD exosomes can construct a fertile environment to support tumor proliferation, angiogenesis, invasion and premetastatic niche preparation. TD exosomes also may facilitate tumor growth and metastasis by inhibiting immune surveillance and by increasing chemoresistance via removal of chemotherapeutic drugs. Therefore, TD-exosomes might be potential targets for therapeutic interventions via their modification or removal. For example, exosomes can serve as specific delivery vehicles to tumors of drugs, small molecules, or agents of prevention and gene therapy. Furthermore, the biomarkers detected in exosomes of biological fluids imply a potential for exosomes in the early detection and diagnosis, prediction of therapeutic efficacy, and determining prognosis of cancer. Although exosomes may serve as cancer biomarkers and aid in the treatment of cancer, we have a long way to go before we can further enhance the anti-tumor therapy of exosomes and develop exosome-based cancer diagnostic and therapeutic strategies.

Upregulation of IGF1 by tumor-associated macrophages promotes the proliferation and migration of epithelial ovarian cancer cells

“…Additionally, these results provide evidence that IGF1 may be a key factor in the promotion of EOC progression through TAMs, explaining its high expression in EOC. Finally, we propose that the mechanism of the upregulation of IGF1 in ID8 cells through TAMs may involve exosomes, which could transfer microRNAs, mRNAs, DNA fragments and proteins, particularly miRNA, from donor cells to recipient cells (42) or secrete cytokines, which also play an important role in the communication between different cells (43). However, these hypotheses need further experimental validation.…”

Expanding the Paracrine Hypothesis of Stem Cell–Mediated Repair in the Heart

“…Moreover, exosome cargo varies, depending on the health status of the tissue of origin, thus serving as biomarkers of specific tissue health status. This was first discovered in cancer studies, where it was shown that plasma levels of substances peculiar to cancer cells could serve as biomarkers of disease progression 5 . Since then, identifying the contents of exosomes from plasma has revealed molecular signatures of numerous pathologies, including heart failure and myocardial infarction.…”

WITHDRAWN: Lack of miR-216b-5p, miR-33a-5p or miR-122-5p in MSCs exosomes promotes breast cancer glycolysis by targeting HK2, LDHA and PKM2

“…Exosomes are small membrane-bound nanovesicles with the characteristic size of 30-120 nm in diameter [5]. Exosomes are generated from endosomal origins constitutively, released by various cells, and more frequently by tumor cells [6][7][8].…”