Exercise-induced microbiota metabolite enhances CD8 T cell antitumor immunity promoting immunotherapy efficacy

Exercise improves immune checkpoint inhibitor (ICI) efficacy in cancers like melanoma, however, the mechanisms through which exercise mediates this antitumor effect remain obscure. Here we identify the gut microbiota as playing a previously unrecognized, critical role in how exercise improves ICI efficacy in preclinical melanoma. Our study demonstrates that exercise stimulates microbial one-carbon metabolism, increasing levels of the metabolite formate, which subsequently enhances Tc1-mediated ICI efficacy. We further establish that microbiota-derived formate is both sufficient and required to enhance Tc1 cell fate in vitro and promote tumor antigen-specific Tc1 immunity in vivo. Mechanistically, we identified the transcription factor nuclear factor erythroid 2-related factor-2 (Nrf2) as a crucial mediator of formate-driven Tc1 function enhancement in vitro and a key player in the exercise-mediated antitumor effect in vivo. Finally, we identify human microbiota-derived formate as a potential biomarker of enhanced Tc1-mediated antitumor immunity and support its functional role in driving melanoma suppression.