A Programmable Nanoreactor Orchestrates Cascade of DNA Sensing to Amplify cGAS-STING Activation for Cancer Immunotherapy.

The cGAS-STING pathway, a critical cytosolic DNA-sensing mechanism in innate immunity, holds significant promise for cancer immunotherapy. However, conventional DNA-damaging therapies lack tumor specificity and cause damage to normal tissue. Furthermore, dendritic cells (DCs), central to the STING-mediated immune response, exhibit extrinsic immunosuppression via inhibitory receptors such as T-cell immunoglobulin and mucin-domain containing-3 (TIM-3), which impairs DNA internalization and subsequent pathway activation. Herein, we engineered a telomere stress-induced nanoreactor composed of a pH-responsive zeolitic imidazolate framework-8 encapsulating telomerase-targeted 6-thio-2'-deoxyguanosine (6-thio-dG), with TIM-3 antibodies (αTIM-3) adsorbed onto its surface. Following accumulation in the tumor, the nanoreactor degrades within the acidic tumor microenvironment, releasing 6-thio-dG to induce tumor cell-specific telomeric DNA damage. Concurrently, the αTIM-3 blocks TIM-3 receptors on DCs, thereby enhancing their internalization of the released DNA. This dual-action strategy drives robust cGAS-STING activation, enhancing type I interferon production and DCs maturation. In murine models of immunogenic and poorly immunogenic tumors, the nanoreactor significantly suppresses tumor growth and prolongs survival. By coupling tumor-intrinsic telomere stress with DC-extrinsic checkpoint inhibition, this work establishes a precision platform for cGAS-STING pathway activation, presenting a promising therapeutic strategy for telomerase-positive malignancies.