Sonodynamic-immunomodulatory nanostimulators activate pyroptosis and remodel tumor microenvironment for enhanced tumor immunotherapy

Rationale: Spatiotemporal control of pyroptosis has a profound impact on cancer immunotherapy. Owing to the precise spatiotemporal control and reduction in the side effects of ultrasound (US), sonodynamic therapy (SDT) is expected to be a promising mean to activate pyroptosis. Furthermore, the pyroptosis-initiated immune response can be amplified by enhanced lymphocyte infiltration occurring due to extracellular matrix (ECM) depletion. Therefore, it is highly desirable to develop a sonodynamic-immunomodulatory strategy to amplify pyroptosis-mediated tumor immunotherapy by remodeling of the tumor microenvironment, thereby enhancing tumor immunotherapy. Methods: We reported a potent strategy based on a sonosensitizer, which is composed of LY364947-loaded porous coordination network (PCN-224) camouflaged with a red blood cell (RBC) membrane and evaluated pyroptosis activation, collagen depletion, immunocyte infiltration, and adaptive immune response during the pyroptosis-initiated immune response in vitro and in vivo. Results: The sonosensitizer generated reactive oxygen species (ROS) under US irradiation and initiated the caspase-3 apoptotic signaling pathway, which is regarded as the key upstream activator of gasdermin E (GSDME)-mediated pyroptosis. During the subsequent anti-tumor immune response mediated by pyroptosis, LY364947 loosened the ECM structure via collagen depletion, resulting in enhanced T-lymphocyte infiltration and nearly complete eradication of tumors in a mouse model with the formation of immunological memory. Conclusion: Our findings indicate that sonodynamic-immunomodulatory pyroptotic strategy exhibits robust anti-tumor immune efficacy as well as provides novel insights into the role of pyroptosis in cancer immunology.