A trinity STING-activating nanoparticle harnesses cancer cell STING machinery for enhanced immunotherapy

The cGAS-STING axis is a promising therapeutic target against cancer. However, most activators require STING signaling in the host, especially within antigen-presenting cells, which are rare in a cold tumor microenvironment. The cGAS-STING cascade is also present within cancer cells but with suppressed activity. Such a paradoxical situation may account for the clinical failures. Herein, we develop a trinity STING-activating nanoparticle (CMTP) coordinated with cGAMP, Mn³⁺, and porphyrin to awaken autologous STING signaling in cancer cells. CMTP disintegrates into Mn²⁺ and TCPP upon elevated glutathione in cancer cells, where TCPP triggers mitochondrial DNA leakage, enhancing cGAS enzymatic activity in coordination with Mn²⁺, while concurrent cGAMP release from framework synergizes to amply STING activity. Consequently, CMTP exploits cancer cells as reservoirs for cGAS-STING signaling to promote DC maturation and T cell priming. A single administration of CMTP demonstrates robust efficacy in both hot MC38 and cold 4 T1 murine tumors. Genetic knockout studies confirm that STING in cancer cells, rather than in the host, is critical for antitumor performance. The feasibility of immune modulation is further validated in resected human patient tissues. This work presents a potent STING-activating nanomedicine based on coordination chemistry and underscores the potential of harnessing cancer cells' autologous cGAS-STING machinery in immunotherapy.