Metformin-dependent metabolic reprogramming contributes to efficient anti-tumor immunity.

The rate of cancer incidence and mortality of Type 2 diabetes patients who were taking metformin seem to be decreased, comparing with those taking other drugs. We recently pro- vided compelling evidence showing that the effect might be mediated by immune system, thus, the reversion of exhausted tumor infiltrating CD8T lymphocytes (CD8TIL). Glycolysis is essential in CD8T cell function. However, the metabolism of CD8TIL is locked in a state of oxidative phosphorylation (OxPhos) dominant over glycolysis because of interaction between immune checkpoints and their ligands, and because of extremely low concentration of glu- cose in tumor microenvironment. Metformin increases the glycolysis efficiency, resulting in the conversion of CD8TIL to more active effector memory to fight against cancers.