Alternating current pre-treatment enhances multi-enzymatic activity of high-entropy alloy nanozymes that regulate metabolism for effective tumor immunotherapy

Nanozymes capable of inducing metabolic reprogramming and activating the immune response without external stimuli in vivo are highly pursued for malignant tumor therapy. In this paper, a PtIrFeMoZn high-entropy alloy (HEA) nanozyme is designed and synthesized via a simple one-step hydrothermal method. The HEA nanozymes not only trigger apoptosis and ferroptosis via cascade biocatalysis, thereby enhancing immunogenicity, but also enhance the immune effect by targeting the glycolytic pathway. It is worth mentioning that a simple pre-treatment of nanozymes by alternating current (AC) yielded much better therapeutic and immuno-effect. The 'AC-treated' nanozymes exhibit an excellent synergy of peroxidase-like (POD-like), myeloperoxidase-like (MPO-like), and glutathione peroxidase-like (GPx-like) activities, generating a sufficient reactive oxygen species (ROS) storm. Additionally, two immune pathways (ICD and the cGAS-STING) are activated simultaneously. Furthermore, the production of HClO and the depletion of NADH can regulate metabolism, further disrupting the equilibrium of the glycolysis process. This not only increases the cell death but also enhances the immune response in female tumor-bearing mice. This study proposes a multi-pronged therapeutic strategy that can significantly activate anti-tumor immunotherapeutic effects through ROS storm, GSH/NADH oxidation, and lactate/ATP depletion, triggering apoptosis/ferroptosis/immunotherapy. These findings hold significant promise for inspiring the development of HEA nanozymes for tumor immunotherapy.