(106c) Rewiring T Cell Fate: A Systems and Computational Approach to Engineering a Master Regulator of Exhaustion and Metabolic Dysfunction in T Cell Therapy for Cancer

Adoptive T cell immunotherapy as a “living drug” has brought cures to many previous untreatable cancers. A major challenge in adoptive T cell therapy is overcoming the multifaceted dysfunction that limits its efficacy—chiefly, T cell exhaustion and mitochondrial failure. While previous strategies have attempted to address these barriers individually, a more powerful approach lies in engineering master regulators that simultaneously reprogram multiple dysfunctions. Through a Systems-Immunology guided CRISPR-Cas9 screen targeting protein homeostasis pathways, we identified a key E3 ubiquitin ligase as an orchestrator of T cell fate. Chronic antigen stimulation suppresses its expression, driving two interlinked failures: accumulation of exhaustion-inducing transcription factors and severe mitochondrial impairment. Our study reveals that reinstating this E3 ligase in engineered T cells rewires metabolic fitness, restores mitochondrial integrity, and recalibrates exhaustion dynamics, leading to significantly enhanced persistence and anti-tumor efficacy across multiple solid tumor models. Single-cell transcriptomics of tumor-infiltrating lymphocytes from over 300 patients further underscore its role as a central node linking proteostasis, metabolism, and T cell immunity. By leveraging this multi-functional regulator, we introduce a next-generation T cell engineering strategy—one that goes beyond checkpoint blockade and single-gene modifications to holistically reprogram T cell fate. This approach represents a potential paradigm shift in immunotherapy, offering a transformative blueprint for engineering resilient, long-lived T cells that can sustain potent anti-tumor responses in the face of persistent immune suppression in cancer.