Copper Oxide-Loaded Graphdiyne Nanocomposites with Hyperthermia-Enhanced Nanozyme Activity for Cuproptosis-Apoptosis Anticancer Therapy.

Cuproptosis is an emerging copper-dependent form of regulated cell death, mechanistically distinct from apoptosis, pyroptosis, and other canonical cell-death pathways, and holds considerable potential for tumor therapeutic applications. In the present study, graphdiyne (GDY) serves as an ideal substrate for the firm immobilization and homogeneous dispersion of CuO nanoparticles. Subsequent polyethylene glycol (PEG) functionalization further enhances the biocompatibility of the hybrid system, yielding CuO/GDY-PEG nanocomposites. The catalase and peroxidase-like activities of CuO nanozymes alleviate hypoxia in the tumor microenvironment (TME) and generate cytotoxic reactive oxygen species, which inducing tumor-cell apoptosis. In addition, this nanocomposite can sustainably deplete glutathione in the TME, disrupt the oxidative balance of the TME, and improve therapeutic efficiency. Photothermal therapy is introduced to facilitate hyperthermia-enhanced tumor nanocatalytic therapy synergistically. More importantly, the intracellular copper overload of tumor cells is caused by the entry of CuO/GDY-PEG nanocomposites into cells. After internalization into tumor cells, CuO/GDY-PEG nanocomposites release Cu2+, which accumulates intracellularly in a mitochondrial-respiration-dependent manner. FDX1 mediates the reduction of Cu2+ to toxic Cu+. The generated Cu+ then binds to lipoylated DLAT and triggers DLAT oligomerization. The formation of insoluble DLAT aggregates elevates cytotoxicity and ultimately drives cuproptosis-mediated cell death. This may synergize with apoptosis to fight tumors systemically.