Cell invasion in the spheroid sprouting assay: a spatial organisation analysis adaptable to cell behaviour

Area of Science:

• * Cell biology
• * Angiogenesis research
• * In vitro modeling

Background:

• * The endothelial cell spheroid assay is a standard in vitro model for studying (lymph) angiogenesis.
• * Current methods typically measure overall cell invasion, potentially missing localized changes.
• * Accurate assessment of angiogenic factors and drug efficacy requires detailed analysis of cellular responses.

Purpose of the Study:

• * To introduce and validate a novel method for analyzing the spatial distribution of migrated cells in endothelial spheroids.
• * To characterize local spheroid structure and monitor both single and collective cell invasion.
• * To provide a more sensitive and accurate descriptor of the (lymph) angiogenic response.

Main Methods:

• * Development of a new analytical method focusing on the spatial distribution of migrated endothelial cells within spheroids.
• * Application of the method to 2D images from optical microscopy and 3D images from confocal microscopy.
• * Validation through evaluation of endothelial cell invasion under various experimental conditions.

Main Results:

• * The spatial distribution analysis provides a detailed, local characterization of spheroid structure and cell invasion.
• * This method captures dynamic changes within the spheroid core and surrounding cell migration.
• * Comparison with global parameters demonstrates the proposed method's ability to prevent misinterpretation of results.

Conclusions:

• * Analyzing spatial cell distribution offers a superior method for evaluating (lymph) angiogenic responses in vitro.
• * The technique enhances the understanding of both single and collective cell invasion dynamics.
• * This novel approach improves the reliability of in vitro angiogenesis assays for drug screening and basic research.