Nanotransferrin-Based Programmable Catalysis Mediates Three-Pronged Induction of Oxidative Stress to Enhance Cancer Immunotherapy.

Current oxidative stress amplifying strategies for immunogenic cell death (ICD) promotion are mainly restricted to immune tolerance induced by adaptive cellular antioxidation, limited tumor-selectivity, and tumoral immunosuppression. Herein, a facile and efficient scenario of genetically engineering transferrin-expressing cell membrane nanovesicle encapsulated IR820-dihydroartemisinin nanomedicine (Tf@IR820-DHA) was developed to boost a-PD-L1-mediated immune checkpoint blocking (ICB) via synergetic triple stimuli-activated oxidative stress-associated ICD. We demonstrate that the engineered transferrin of Tf@IR820-DHA has excellent tumor targeting and Fe(III)-loading properties and thus delivered Fe(III) and IR820-DHA nanoparticles (NPs) to the lesion location effectively. We found that the self-carrying Fe(III)-mediated programmable catalysis of DHA and glutathione (GSH) depletion generated plenty of reactive oxygen species (ROS). Moreover, DHA also acted as an immunomodulator to decrease the number of T regulatory cells, thereby remodeling the tumor immune microenvironment and achieving double T cell activation. Furthermore, the IR820 molecule served as a competent sonosensitizer to produce ROS under ultrasound activation and guide precise immunotherapy via fluorescent/photoacoustic (FL/PA) imaging. Through its three-pronged delivery of stimuli-activated oxidative stress (DHA-induced chemodynamic therapy, catalysis-conferred GSH depletion, and IR820-mediated sonodynamic therapy), Tf@IR820-DHA caused high levels of targeted ICD. This significantly increased the proportions of IFN-γ-secreting T cells (CD4+ T and CD8+ T) and enhanced a-PD-L1-mediated ICB against primary and distant tumors, which represents a promising approach for cancer nanoimmunotherapy.