Matrix reboot: IL-17 signals CAFs to create a second tumor T cell checkpoint

Area of Science:

• Immunology
• Oncology
• Cell Biology

Background:

• Checkpoint inhibitor therapies are limited by excessive collagen deposition around tumors.
• This dense extracellular matrix creates an immune-excluded tumor microenvironment, reducing treatment effectiveness.

Purpose of the Study:

• To investigate the role of IL-17 in promoting collagen deposition by cancer-associated fibroblasts.
• To explore targeting IL-17 signaling as a strategy to overcome immune exclusion and enhance immunotherapy.

Main Methods:

• Analysis of tumor microenvironments and fibroblast activity.
• Investigating the signaling pathways involving IL-17, cancer-associated fibroblasts, and collagen production.
• Evaluating the impact of targeting IL-17-triggered HIF1α expression on immune cell infiltration.

Main Results:

• Interleukin-17 (IL-17) was identified as a key driver of collagen deposition by cancer-associated fibroblasts.
• This IL-17-induced matrix deposition leads to immune exclusion, limiting checkpoint inhibitor efficacy.
• Targeting the IL-17-triggered HIF1α pathway reversed matrix-mediated immune exclusion in preclinical models.

Conclusions:

• IL-17 plays a critical role in establishing an immune-excluded tumor microenvironment through fibroblast activation and collagen synthesis.
• Modulating the IL-17/HIF1α axis presents a promising therapeutic strategy to enhance anti-tumor immunity and improve responses to immunotherapy.