"Threefold dual" copper homeostasis regulation strategy: Targeted copper surge for enhanced cancer immunotherapy

ABSTRACT Copper-based therapeutics disrupting intracellular copper homeostasis hold immense promise for cancer immunotherapy, yet their efficacy is severely limited by inadequate copper accumulation, intratumoral antioxidant defenses, and nonspecific drug release. To surmount these limitations, we engineered CuTF-DC_AC50, an innovative copper homeostasis nanomodulator implementing a "threefold dual" strategy to maximize therapeutic outcomes. Specifically, the nanomodulator drives massive copper overload through a dual-channel influx and efflux regulation mechanism, concurrently delivering exogenous Cu 2+ and inhibiting ATOX1-mediated copper efflux via its DC_AC50 component. Simultaneously, it dismantles the intracellular antioxidant barrier through dual-mechanism glutathione (GSH) depletion, mediated by disulfide bond cleavage within the TPH scaffold alongside Cu 2+ reduction. Furthermore, CuTF-DC_AC50 undergoes dual-responsive degradation triggered by the acidic and GSH-abundant tumor microenvironment (TME), enabling precise drug release and spatial-temporal orchestration of the therapeutic cascade. This targeted copper surge synergistically triggers cuproptosis and pyroptosis, thereby robustly activating immunogenic cell death (ICD). Consequently, in vivo investigations demonstrate that this nanomodulator profoundly remodels the immunosuppressive TME, promotes robust immune cell infiltration, and substantially suppresses tumor growth. By exploiting the CuTF-DC_AC50-induced PD-L1 upregulation, its combination with αPD-L1 markedly amplifies therapeutic efficacy in CT26 tumor-bearing mice, establishing a highly programmable and clinically translatable combinatorial strategy for potentiated cancer immunotherapy.