Plasma exosomes from Head and Neck Cancer patients: pro- or anti-angiogenic mediators?

Introduction Angiogenesis is a key regulatory mechanism in the carcinogenesis of head and neck cancer (HNC). While exosomes derived from HNC cell lines (TEX) have shown to reprogram endothelial cells (ECs) and thus promote angiogenesis, the role of plasma exosomes still remains unclear.

Methods Plasma exosomes were isolated from 18 HNC patients and 12 normal donors (NDs) by size exclusion chromatography. The morphology of the exosomes was analyzed by transmission electron microscopy (TEM) and the interaction of fluorescently labeled exosomes with ECs was visualized by confocal microscopy (CM). Angiogenesis-associated proteins were detected using antibody arrays. Functional assays (MTS assay, wound healing assay, tube formation assay) were performed to analyze the effect of exosomes on the proliferation, migration and tubulogenesis of human umbilical vein ECs.

Results Plasma exosomes appeared typical in shape and size in TEM and CM demonstrated their internalization by ECs. Antibody arrays showed an enrichment of anti-angiogenic proteins rather than pro-angiogenic proteins in HNC exosomes. In functional assays, HNC plasma exosomes inhibited proliferation, migration and tubulogenesis of ECs in comparison to untreated cells.

Conclusion In contrast to TEX, plasma HNC exosomes show rather anti-angiogenic effects. Since TEX comprise only a small portion of all plasma exosomes, further investigation of non-TEX and TEX within the plasma is required to evaluate their angiogenic potential in HNC.

Deutsche Forschungsgemeinschaft (DFG), Stiftung für Krebs- und Scharlachforschung der Universität Heidelberg

 

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Conflict of Interest

The author declares that there is no conflict of interest.

Publication History

Article published online:
24 May 2022