Exosomes released by k562 chronic myeloid leukemia cells promote endothelial cell tubular differentiation through uptake and cell-to-cell transfer

Exosomes, microvesicles of endocytic origin released by normal and tumor cells, play an important role in cell-to-cell ommunication. Angiogenesis has been shown to regulate progression of chronic myeloid leukemia (CML). The mechanism through which this happens has not been elucidated. We isolated and characterized exosomes from K562 CML cells and evaluated their effects on human umbilical endothelial cells (HUVECs). Fluorescent-labeled exosomes were nternalized by HUVECs during tubular differentiation on Matrigel. Exosome localization was perinuclear early in differentiation, moving peripherally in cells undergoing elongation and connection. Exosomes move within and between nanotubular stru…