Nanomedicine for combination of chemodynamic therapy and immunotherapy of cancers.

Chemodynamic therapy (CDT), as a new type of therapy, has received more and more attention in the field of tumor therapy in recent years. By virtue of the characteristics of weak acidity and excess H 2 O 2 in the tumor microenvironment, CDT uses the Fenton or Fenton-like reactions to catalyze the transformation of H 2 O 2 into strongly oxidizing ˙OH, resulting in increased intracellular oxidative stress for lipid oxidation, protein inactivation, or DNA damage, and finally inducing apoptosis of cancer cells. In particular, CDT has the advantage of tumor specificity. However, the therapeutic efficacy of CDT frequently depends on the catalytic efficiency of the Fenton reaction, which needs the presence of sufficient H 2 O 2 and catalytic metal ions. Relatively low concentrations of H 2 O 2 and the lack of catalytic metal ions usually limit the final therapeutic effect. The combination of CDT with immunotherapy will be an effective means to improve the therapeutic effect. In this review paper, the recent progress related to nanomedicine for the combination of CDT and immunotherapy is summarized. Immunogenic death of tumor cells, immune checkpoint inhibitors, and stimulator of interferon gene (STING) activation as the main immunotherapy strategies to combine with CDT are discussed. Finally, the challenges and prospects for the clinical translation and future development direction are discussed.