CD133-containing microvesicles promote colorectal cancer progression by inducing tumor angiogenesis

Angiogenesis is an indispensable mechanism in cancer progression, as cancer cells need to establish blood vessels to supply oxygen and nutrients. Extracellular vesicles (EVs) derived from cancer cells act as messengers in the tumor microenvironment and induce resistance to anti-angiogenic cancer treatment. EVs can be classified into two categories: exosomes and microvesicles (MVs). Although exosomes are involved in angiogenesis, the role of MVs in angiogenesis and cancer progression remains unclear. CD133 plays a key role in MV formation and oncoprotein trafficking. In this study, we investigated the role of CD133-containing MVs derived from colorectal cancer (CRC) in angiogenesis and cancer progression. CRC-derived MVs were incorporated into endothelial cells and increased the mesh area and tube length of endothelial cells. CD133-containing MVs also stimulate vessel sprouting in endothelial cell spheroids and mouse thoracic aortas. However, MVs derived from CD133-knockdown CRC cells exerted a limited effect on tube formation and vessel sprouting. CD133-containing MVs induced angiogenesis through p38 activation and angiogenesis induced by CD133-containing MVs was insensitive to the anti-vascular endothelial growth factor antibody bevacizumab. Survival analysis revealed that high expression level of CD133 correlated with poor prognosis in patients with metastatic CRC. These findings suggest that CD133-containing MVs act as key regulators of angiogenesis and are related to the prognosis of CRC patients.