Epithelial-to-mesenchymal transition (EMT) is a dynamic program of cell plasticity aberrantly reactivated in cancer. The crosstalk between tumor cells and the tumoral microenvironment (TME) has a pivotal importance for the induction of the EMT and the progression toward a malignant phenotype. Notably, exosomes are key mediators of this crosstalk as vehicles of specific molecular signals that include the class of circular RNAs (circRNAs). This review specifically focuses on the role of exosome-associated circRNAs as key regulators of EMT in cancer. The relevance of these molecules in regulating the intercellular communication in TME and tumor progression is highlighted. Moreover, the here-presented evidence indicates that exosome-associated circRNA modulation should be taken in account for cancer diagnostic and therapeutic approaches.
Keywords: circular RNAs; epithelial tumor progression; epithelial-to-mesenchymal transition; extracellular vesicles; tumor microenvironment (TME).