Mouse Tumor Tissue-Derived Extracellular Vesicles Induce Angiogenesis Through VEGF Production From Macrophages

Area of Science:

• Oncology
• Cell Biology
• Biochemistry

Background:

• Extracellular vesicles (EVs) mediate intercellular communication and are implicated in various diseases.
• Angiogenesis is crucial for tumor growth, supplying nutrients and oxygen.
• The angiogenic role of EVs directly from in vivo tumor tissues remains largely unexplored.

Purpose of the Study:

• To investigate the angiogenic potential of EVs isolated directly from in vivo mouse primary tumor tissues (tEVs).
• To elucidate the mechanisms underlying tEV-mediated angiogenesis in the tumor microenvironment.

Main Methods:

• Isolation of high-purity EVs from mouse primary tumor tissues.
• Characterization of isolated tEVs for EV-like features and protein markers.
• In vivo Matrigel plug assay to assess neovascularization and macrophage infiltration.
• Analysis of macrophage-derived vascular endothelial growth factor (VEGF) production.

Main Results:

• Purified tEVs exhibited typical nano-sized, spherical, and lipid bilayered structures, enriched with EV markers.
• In vivo assays demonstrated that tEVs significantly promoted neovascularization and macrophage infiltration.
• Tumor tEV-induced angiogenesis was mediated by infiltrated macrophages producing VEGF.

Conclusions:

• In vivo tumor tissue-derived EVs possess potent angiogenic activity.
• tEVs directly promote macrophage recruitment and activation, leading to VEGF production.
• This study provides the first direct evidence for macrophage VEGF production in tEV-mediated tumor neovascularization.