Fig. 1
From: Functional roles of circular RNAs during epithelial-to-mesenchymal transition
CircRNA plays an important role in tumor metastasis. During EMT, circRNA absorbing miRNA attenuates the inhibition of the miRNA on EMT-related genes, such as EMT-TF/E-cad, N-cad, vimentin and cdc42. As a result, epithelial cells lose their characteristics, such as cell-to-cell adhesion and cell polarity. Instead, the cells gain motility, migratory potential, and invasive properties, becoming mesenchymal stem cells. In addition, EMT triggers primary tumor cells to enter the circulatory or lymphatic system. Then, circulating tumor cells are transported to distant tissues or organs to form secondary metastatic deposits through EMT. Of note, circRNAs secreted as exosomes are detected in serum/urine, which provides a novel strategy for the diagnosis and treatment of cancer