Biomimetic self-assembled copper nanoadjuvant potentiates hepatocellular carcinoma immunotherapy via cuproptosis-driven cGAS-STING activation

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 Cu 2+ 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 Cu 2+ 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.