pH-triggered Mn-ZIF8 nanoreactor enhances tumor immunotherapy by amplifying the cGAS-STING pathway through a self-reinforcing gas-metal synergy strategy
摘要
Although conventional immunotherapies have significantly transformed cancer treatment, their efficacy is still fundamentally limited by the immunosuppressive tumor microenvironment and systemic toxicity. In this study, we propose a Gas-Metal Synergy Strategy, which integrates immune activation and biosafety, by engineering a pH-responsive manganese-based zeolitic imidazolate framework (named MRPH) nanoplatform co-loaded with the nitric oxide (NO) donor RRX-001. MRPH selectively dissociates in the acidic TME, releasing Mn²⁺ and NO, which together amplify the activation of the cGAS-STING pathway through a synergistic mechanism: NO induces mitochondrial damage and the cytosolic release of mtDNA, while Mn²⁺ enhances the sensitivity of cGAS to mtDNA. Simultaneously, PEG-HA-modified nanoparticles enable tumor-targeted delivery, and this spatiotemporal coordination triggers immunogenic cell death, dendritic cell maturation, and CD8⁺ T cell infiltration, while inhibiting CD47-mediated immunosuppression and promoting tumor vascular normalization. Furthermore, our findings indicate that manganese-related genes are linked to immune modulation and tumor microenvironment remodeling in osteosarcoma patients. Both in vitro and in vivo studies demonstrate that MRPH significantly enhances gas-amplified metalloimmunotherapy. This work pioneers a low-toxicity paradigm that integrates gas therapy and metal-based immunotherapy, offering a transformative approach to solid tumor immunotherapy.