Sirt2 Inhibition Reprograms T Cell Metabolism to Confer Superior Anti-Tumor Immunity

Dysregulated metabolism is a key driver of maladaptive tumor-reactive T lymphocytes within the tumor microenvironment (TME). Actionable mechanisms that rescue the effector activity of anti-tumor T cells in a metabolically restricted TME remain elusive. Here, we report that the Sirtuin-2 (Sirt2) protein deacetylase functions as a master metabolic checkpoint that inhibits T cell metabolic fitness and impairs T cell effector functions and anti-tumor immunity. Mechanistically, Sirt2 suppresses glycolysis and oxidative-phosphorylation (OxPhos) by deacetylating key enzymes involved in glycolysis, tricarboxylic acid (TCA)-cycle, fatty acid oxidation (FAO) and glutaminolysis. Accordingly, Sirt2-deficient T cells exhibit a hyper-metabolic activity with increased glycolysis and OxPhos, resulting in enhanced proliferation and effector functions at tumor beds and subsequently exhibiting superior anti-tumor activity. Importantly, pharmacologic inhibition of Sirt2 endows human lung tumor-infiltrating lymphocytes (TILs) with these superior metabolic fitness and enhanced effector functions. Furthermore, upregulation of Sirt2 expression in human TILs negatively correlates with response to Nivolumab and TIL therapy in non-small cell lung cancer (NSCLC). Our findings unveil Sirt2 as an unexpected actionable target for reprogramming T cell metabolism to augment a broad spectrum of cancer immunotherapies.