Biomimetic self-assembled copper nanoadjuvant potentiates hepatocellular carcinoma immunotherapy via...

Immunotherapy has reshaped cancer treatment, yet its efficacy in many solid tumors remains limited by an immunosuppressive microenvironment and insufficient antigen presentation. As a central gatekeeper of antitumor immunity, the cGAS-STING pathway represents a key axis for converting tumor-intrinsic stress into productive immune priming. Here, we propose an integrated strategy that couples immunogenic tumor cell death with tumor-restricted cGAS-STING activation and adjuvant-amplified innate signaling. Cuproptosis, a recently identified copper-dependent cell-death program, can act as an endogenous trigger of tumor-intrinsic cGAS-STING activation, providing a promising avenue to link cytotoxicity with immune stimulation. We engineered a biomimetic, tumor-responsive nanoplatform (Cu-R837@CM) by co-assembling Cu²⁺ with the TLR7 agonist R837 and cloaking the core with homologous tumor cell membranes to enhance tumor targeting and intratumoral retention. In vitro, Cu-R837@CM released Cu²⁺ under acidic conditions, inducing glutathione depletion and ROS accumulation, promoting DLAT aggregation and mitochondrial dysfunction, increasing intracellular 2'3'-cGAMP, and activating cGAS-STING signaling. Concurrently, R837 enhanced dendritic-cell maturation and cytokine production, thereby improving antigen presentation. In vivo, Cu-R837@CM markedly inhibited tumor growth, increased CD4⁺/CD8⁺ T-cell infiltration, and remodeled the tumor immune microenvironment toward an antitumor phenotype. Notably, combining Cu-R837@CM with PD-L1 blockade achieved complete tumor regression and significantly prolonged survival. Collectively, Cu-R837@CM offers a clinically translatable nanoadjuvant paradigm that integrates cuproptosis-driven cGAS-STING activation with TLR7 co-stimulation for hepatocellular carcinoma immunotherapy.