A powerful agonist for metal ion interference therapy: Multiple programs of cell death to amplify tumor metalloimmunotherapy.

Metal ion interference therapy (MIIT), which induces multiple programs of cell death, has emerged as a promising approach for combatting cancer. However, the efficient delivery of multiple metal ions and ion resistance by cellular metabolism present challenges, thereby impeding its progress. Herein, a novel MIIT initiator, layered double hydroxides composite, disulfiram (DSF)-loaded ZnCuAl-LDH, was constructed to efficiently co-deliver multiple metal ions and enhance the retention ability of metal ions within the cells. In an acidic environment, the ZCA-LDH@DSF initiator enabled pH-responsive release of Zn2+/Cu2+ and the DSF drug. On the one hand, Cu2+ and DSF in situ combined to form highly toxic CuET, inducing DNA damage and cell apoptosis. On the other hand, intracellular Cu2+ overload disrupted tricarboxylic acid cycle (TCA), leading to significant cuproptosis. Concurrently, intracellular Zn2+ inhibited the expression of the copper transport proteins ATP7A and ATP7B, reducing Cu2+ efflux and promoting intracellular Cu2+ accumulation, thereby further amplifying cuproptosis. Moreover, intracellular Zn2+ also induced pyroptosis via the caspase-1/gasdermin D (GSDMD)-dependent pathway, synergizing with CuET-induced cell apoptosis and cuproptosis to significantly enhance immunogenic cell death (ICD), which is favorable for MIIT in tumors. Therefore, ZCA-LDH@DSF demonstrated a remarkable ability to induce MIIT, thereby triggering multiple programs of cell death and inhibiting tumor growth and metastasis. Overall, the good biological safety and application prospect of ZCA-LDH@DSF initiator provide a new treatment model for combating tumor.