Bidirectional Endothelial Feedback Drives Turing-Vascular Patterning and Drug-Resistance Niches: A Hybrid...

Area of Science:

• Computational Biology
• Mathematical Oncology
• Biophysics

Background:

• Tumor growth and treatment efficacy are significantly impacted by tumor microenvironment heterogeneity, particularly vascularization.
• Perfusion heterogeneity in tumors leads to variable oxygen and drug distribution, fostering treatment resistance.
• Understanding the interplay between tumor angiogenic factor (TAF) and endothelial cell behavior is crucial for developing effective therapies.

Purpose of the Study:

• To develop and analyze a multiscale hybrid partial differential equation-agent-based model (PDE-ABM) integrating tumor cells, endothelial cells, and molecular signaling.
• To investigate how endothelial cell feedback mechanisms, specifically TAF secretion and chemotaxis, drive vascular pattern formation.
• To identify key parameters that influence vascular heterogeneity and drug penetration, and to propose strategies for mitigating treatment resistance.

Main Methods:

• Development of a coupled PDE-ABM framework simulating TAF, oxygen, and drug dynamics alongside discrete endothelial and tumor cell behaviors.
• Linear stability analysis of a reduced endothelial-TAF reaction-diffusion subsystem to identify conditions for Turing instability.
• Simulation of emergent vascular patterns and assessment of their impact on drug penetration and hypoxic region formation.

Main Results:

• Bidirectional coupling between endothelial cell migration along TAF gradients and TAF secretion is necessary and sufficient for generating spatially periodic vascular clusters.
• These emergent vascular patterns create inter-cluster hypoxic regions, resulting in heterogeneous drug penetration and the development of resistant cell niches.
• TAF clearance, chemotactic sensitivity, and endothelial motility were identified as critical parameters for homogenizing tumor perfusion.

Conclusions:

• The hybrid PDE-ABM effectively captures multiscale dynamics driving tumor vascularization and heterogeneity.
• Targeting the endothelial-TAF feedback loop offers a potential strategy to improve drug delivery and overcome treatment resistance.
• The study provides a foundation for future extensions to 3D and saturable kinetics for quantitative clinical applications.