DGKζ exerts greater control than DGKα over CD8⁺ T cell activity and tumor inhibition

Area of Science:

• Immunology
• Molecular Biology
• Cancer Research

Background:

• Diacylglycerol kinases (DGKs) regulate T cell signaling pathways crucial for immune responses.
• DGKα and DGKζ isoforms are key in terminating DAG-mediated activation of Ras and PKCθ pathways in T cells.
• Direct comparative studies on tumor growth in mice lacking specific DGK isoforms were lacking.

Purpose of the Study:

• To compare the effects of DGKα and DGKζ deficiency on tumor growth.
• To evaluate the combined impact of DGK isoform deficiency and anti-PD1 therapy on tumor control.
• To investigate the functional and molecular differences between DGKα- and DGKζ-deficient T cells.

Main Methods:

• Syngeneic tumor models in mice lacking DGKα or DGKζ.
• Treatment with anti-PD1 immunotherapy.
• Tumor growth assessment.
• Functional assays and RNA-sequencing of stimulated T cells.

Main Results:

• Mice deficient in DGKζ exhibited enhanced tumor control compared to those deficient in DGKα.
• DGKζ deficiency demonstrated an additive effect with anti-PD1 therapy in controlling tumor growth.
• DGKζ-deficient T cells showed more significant functional and transcriptomic changes than DGKα-deficient T cells.
• DGKζ demonstrated greater regulatory capacity than DGKα in both mouse and human T cells.

Conclusions:

• Targeting the DGKζ isoform offers a promising therapeutic strategy to enhance T cell-mediated anti-tumor immunity.
• DGKζ plays a more critical role than DGKα in regulating T cell responses against tumors.
• Combined targeting of DGKζ and PD-1 blockade may represent an effective approach for cancer immunotherapy.