Cell-autonomous control of CAR signaling and receptor shedding via ADAM17-mediated proteolysis

Area of Science:

• Immunology
• Molecular Biology
• Biotechnology

Background:

• T cell therapies require precise control over cell surface protein expression.
• Current methods for regulating T cell function can be limited in scope and speed.
• Autonomous regulation mechanisms are needed to enhance T cell persistence and efficacy.

Purpose of the Study:

• To engineer a T cell autonomous regulatory system for cell surface protein expression.
• To develop a novel switch based on ADAM17 proteolytic activity.
• To enhance the therapeutic potential of T cell-based cancer therapies.

Main Methods:

• Screening of ADAM17 substrates to identify a regulatory motif.
• Development of the activation-induced release (AIR) system.
• Integration of AIR into chimeric antigen receptor (CAR) T cells and endogenous genes (FAS, TGFBR2) via CRISPR.
• Evaluation of AIR's impact on T cell function, including expression, exhaustion, expansion, and antitumor activity.

Main Results:

• A 15-amino acid CD62L-derived motif, termed activation-induced release (AIR), was identified for rapid and reversible receptor cleavage upon T cell activation.
• Embedding AIR into tonic-signaling CARs reduced basal CAR expression, curtailed exhaustion, and improved antitumor potency.
• In non-tonic signaling CARs, AIR decreased activation-induced cell death and enhanced T cell expansion.
• AIR enabled antigen-dependent logic-gating for CAR unmasking and enhanced tumor clearance when knocked into endogenous FAS or TGFBR2.
• AIR demonstrated modularity for higher-order logic-gating and activation-induced shedding.

Conclusions:

• AIR is a compact and versatile switch for fast, autonomous regulation of surface proteins in T cells.
• This technology holds significant promise for next-generation cell therapies, particularly in oncology.
• AIR enhances T cell function and therapeutic efficacy by controlling cell surface protein expression dynamically.