An in vitro cord formation assay identifies unique vascular phenotypes associated with angiogenic growth factors

Area of Science:

• Biomedical Engineering
• Cell Biology
• Cancer Research

Background:

• Vascular endothelial growth factor (VEGF) pathway inhibitors are used in cancer therapy but face resistance.
• Resistance mechanisms involve upregulation of other pro-angiogenic factors like fibroblast growth factor (FGF) and epidermal growth factor (EGF).
• Existing in vitro angiogenesis assays often use complex media or are VEGF-dependent, limiting the study of other factors.

Purpose of the Study:

• To develop a novel in vitro co-culture system for studying angiogenesis driven by factors other than VEGF.
• To characterize unique angiogenic phenotypes induced by different growth factors.
• To screen for novel pro-angiogenic molecules using a minimal medium assay.

Main Methods:

• Development of a basal medium co-culture system using adipose-derived stem cells (ADSCs) and endothelial colony-forming cells (ECFCs).
• Analysis of cord formation phenotypes induced by VEGF, bFGF, and EGF.
• Multiparametric analysis of growth factor combinations to determine dominant phenotypes.
• Screening of potential pro-angiogenic molecules in the minimal medium assay.

Main Results:

• Different angiogenic factors (VEGF, bFGF, EGF) induced distinct cord formation phenotypes (e.g., smooth muscle actin coverage, node thickness, branching).
• Epidermal growth factor (EGF) exhibited a dominant phenotype in combination studies.
• The assay identified an inhibitor that promoted cord formation, which showed efficacy in in vivo tumor models.

Conclusions:

• The developed assay system allows for the study of angiogenesis driven by specific growth factors.
• Understanding unique growth factor-driven phenotypes can inform combination therapies.
• The assay facilitates the discovery of novel pro-angiogenic molecules with potential therapeutic applications in angiogenesis.