CAR-adapted PIK3CD base editing enhances T cell anti-tumor potency.

Area of Science:

• Immunology
• Cell Biology
• Biotechnology

Background:

• Chimeric antigen receptor (CAR) T cell therapy shows promise but is limited by insufficient T cell persistence.
• T cell function, metabolism, and fate are regulated by phosphatidylinositol-3-kinase delta (PI3Kδ).

Purpose of the Study:

• To identify beneficial point mutations in PIK3CD for enhancing CAR T cell function and persistence using a base-editing screen.
• To investigate the impact of PI3Kδ signaling modulation on distinct CAR T cell types (4-1BBz and 28z).

Main Methods:

• Conducted a CAR-adapted base-editing screen targeting PIK3CD.
• Introduced specific PIK3CD point mutations (E81K and L32P) into CAR T cells.
• Assessed CAR T cell proliferation, metabolism, effector function, and memory formation.

Main Results:

• The PI3Kδ-activating mutation E81K enhanced proliferation, metabolic fitness, and effector function in 4-1BBz CAR T cells, improving in vivo efficacy and persistence.
• The PI3Kδ-attenuating mutation L32P improved memory formation and functionality in 28z CAR T cells.
• Demonstrated CAR design-specific fine-tuning of T cell signaling through targeted allelic reprogramming (ROADSTAR).

Conclusions:

• Base editing can be used to optimize CAR T cell properties for enhanced therapeutic outcomes.
• Tailoring PI3Kδ signaling through specific mutations improves distinct CAR T cell functionalities.
• The ROADSTAR approach offers a powerful strategy for developing next-generation cellular therapies.