Epigenetic reprogramming of T cell metabolism restores function and enhances anti-tumor immunity in lung cancer.

T cell exhaustion represents a critical target for immunotherapy in cancer. Nevertheless, T cells exhibit diminished responsiveness to immune checkpoint inhibitors once they transition to a terminally exhausted state. Here we used an epigenetic drug screen and identified bromodomain and extra-terminal motif inhibitors (BETis) as enhancers of effector functions in primary exhausted T cells (TEX) from malignant pleural effusions in patients with lung cancer. Transcriptomics, metabolomics and ATAC-seq analyses revealed that BETis reinvigorate TEX cells by activating the polyamine biosynthesis pathway, expanding intracellular polyamine pools and altering chromatin accessibility. Genetic and pharmacological inhibition of ornithine decarboxylase (ODC1), a key enzyme in this pathway, abolished BETi-mediated immunopotentiation. Single-cell RNA-seq demonstrated that BETis reduced terminal TEX while promoting progenitor TEX through activation of the MYC-ODC axis. BETi treatment or adoptive transfer of BETi-treated T cells suppressed malignant pleural effusion formation in a syngeneic lung cancer model. These findings highlight an epigenetic-metabolic approach to enhance TEX plasticity and offer insights for novel cancer immunotherapies.