Disrupting CD38-driven T cell dysfunction restores sensitivity to cancer immunotherapy

Area of Science:

• Immunology
• Cancer Biology
• Metabolic pathways

Background:

• Immune checkpoint blockade (ICB) therapy is limited by resistance in approximately 50% of metastatic melanoma patients.
• T cell exhaustion, driven by the tumor microenvironment, is a key mechanism of ICB resistance.
• CD38, an enzyme degrading nicotinamide adenine dinucleotide (NAD+), is implicated in T cell dysfunction.

Approach:

• Investigated CD38 expression in exhausted CD8+ T cells within melanoma.
• Assessed the impact of genetic and pharmacological CD38 blockade in murine and patient-derived tumor models.
• Analyzed the effects of CD38 inhibition on T cell NAD+ metabolism, mitochondrial function, and anti-tumor immunity.

Key Points:

• High CD38 expression on exhausted CD8+ T cells correlates with ICB resistance in melanoma.
• CD38 blockade in tumor models restored T cell proliferation, effector functions, and mitochondrial bioenergetics.
• Disrupting the CD38-NAD+ axis rejuvenated exhausted T cells and sensitized tumors to ICB.

Conclusions:

• The CD38-NAD+ axis plays a critical role in promoting T cell exhaustion and ICB resistance.
• Targeting CD38 represents a promising therapeutic strategy to enhance cancer immunotherapy efficacy.
• Clinically relevant, patient-derived 3D tumor models demonstrate the potential of CD38-directed therapies.