Precise In Situ Delivery of a Photo-enhanceable Inflammasome-Activating Nanovaccine Activates Anti-cancer Immunity

Abstract

A variety of state-of-the-art nanovaccines (NVs) combined with immunotherapies have recently been developed to treat malignant tumors, showing promising results. However, immunosuppression in the tumor microenvironment (TME) restrains cytotoxic T cells infiltration and limits the efficacy of immunotherapies in solid tumors. Therefore, tactics for enhancing antigen cross-presentation and reshaping the TME need to be explored to enhance the activity of NV. Here, we developed a photo-enhanceable inflammasome-activating NV (PIN) to achieve precise in situ delivery of a tumor antigen and a hydrophobic small molecule activating the NLRP3-inflammasome pathway. Near-infrared light irradiation promoted PIN accumulation in tumor sites through photo-triggered charge reversal of the nanocarrier. Systematic PIN administration facilitated intratumoral NLRP3 inflammasome activation and antigen cross-presentation in antigen-presenting cells upon light irradiation at tumor sites. Furthermore, PIN treatment triggered immune responses by promoting the production of proinflammatory cytokines and activated of anti-tumor immunity without significant systematic toxicity. Importantly, the PIN enhanced the efficacy of immune checkpoint blockade and supported the establishment of long-term immune memory in mouse models of melanoma and hepatocellular carcinoma. Collectively, this study reports a safe and efficient photoresponsive system for co-delivery of antigens and immune modulators into tumor tissues with promising therapeutic potential.