A Hybrid Multiscale Model for Predicting CAR-T Therapy Outcomes in Solid Tumors
Abstract:
T cell distribution within tumors ("tumor hotness") critically determines immunotherapy success. However, despite numerous strategies to enhance intratumoral T cell accumulation-such as multi-target CAR-Ts and combinatorial approaches-limited mechanistic understanding of T cell-microenvironment interactions has constrained progress. To address this, we developed a physiological mechanistic model of the 3D tumor microenvironment (TME) to evaluate CAR-T performance under environmental fluctuations and different infusion strategies. The model integrates key vascular (rolling, adhesion, endothelial suppression) and interstitial (ECM density, metabolic competition, chemokine sensitivity) barriers. Our simulations reveal that collagen density and metabolic competition dominate CAR-T efficacy. Enhancing vascular adhesion improves infiltration but remains limited by collagen and metabolism. Endothelial suppression markedly reduces tumor hotness, while its alleviation enhances response. Systemic infusion yields higher tumor hotness than intratumoral delivery, but combined routes or reduced collagen restore efficacy even in dense tumors. This mechanistic framework enables rational optimization of CAR-T strategies.
Significance Statement:
The success of immunotherapies such as CAR-T cells depends on their ability to infiltrate and persist within solid tumors, yet the mechanisms that govern this process remain poorly understood. Using a mechanistic 3D model of the tumor microenvironment, we quantitatively dissected how vascular and interstitial barriers-including endothelial suppression, collagen density, metabolic competition, and chemokine cues-shape CAR-T distribution ("tumor hotness"). Our results reveal that stromal and metabolic constraints, rather than vascular adhesion alone, dominate CAR-T efficacy. This framework bridges molecular, cellular, and tissue-scale mechanisms, providing a quantitative foundation for optimizing CAR-T design and delivery strategies to overcome resistance in solid tumors.
Insights
Optimizing CAR-T cell therapy requires understanding tumor microenvironment barriers. A 3D model reveals collagen density and metabolic competition significantly impact CAR-T cell efficacy in solid tumors.
Area of Science:
- Immunology
- Biomedical Engineering
- Computational Biology
Background:
- CAR-T cell therapy success hinges on T cell infiltration into tumors, termed 'tumor hotness'.
- Limited understanding of T cell-tumor microenvironment interactions hinders immunotherapy progress.
- Existing strategies for enhancing T cell accumulation face challenges due to complex microenvironmental barriers.
Purpose of the Study:
- To develop a physiological mechanistic model of the 3D tumor microenvironment (TME).
- To evaluate CAR-T cell performance under varying environmental conditions and infusion strategies.
- To identify key barriers limiting CAR-T cell efficacy and inform optimization strategies.
Main Methods:
- Developed a 3D mechanistic model integrating vascular (rolling, adhesion, endothelial suppression) and interstitial (ECM density, metabolic competition, chemokine sensitivity) barriers.
- Simulated CAR-T cell distribution and performance within the TME under different conditions.
- Quantitatively analyzed the impact of specific microenvironmental factors on CAR-T cell infiltration and efficacy.
Main Results:
- Collagen density and metabolic competition were identified as dominant factors limiting CAR-T cell efficacy.
- Enhanced vascular adhesion improved infiltration but was ultimately constrained by collagen and metabolism.
- Endothelial suppression significantly reduced tumor hotness; its alleviation improved response.
- Systemic infusion resulted in higher tumor hotness than intratumoral delivery, with combined routes or reduced collagen restoring efficacy in dense tumors.
Conclusions:
- The developed mechanistic framework enables a quantitative understanding of CAR-T cell-TME interactions.
- Stromal and metabolic constraints are more critical than vascular adhesion for CAR-T cell efficacy.
- This model provides a foundation for rational optimization of CAR-T cell design and delivery strategies to overcome resistance in solid tumors.
