Self-Boosting Cuproptosis-Based Synergistic Antitumor Therapy by GSH-Enhanced Cocatalysis and Copper Efflux Inhibition

Cuproptosis efficiency is severely limited by insufficient Cu+ contents in tumors due to the easy oxidation of Cu+ into Cu2+ and the copper efflux mechanism. Herein, we develop a copper nanocarrier (MoSe2/CuO2) that can significantly enhance intracellular Cu+ for self-boosting cuproptosis-based synergistic antitumor therapy. Upon endocytosis by cancer cells, the acidic tumor microenvironment (TME) triggers the degradation of MoSe2/CuO2 to release Cu2+. MoSe2 then acts as a cocatalyst that promotes the reduction of released Cu2+ to Cu+, while oxidizing active Mo4+ to Mo6+, thereby triggering cuproptosis. Importantly, the produced Mo6+ is further returned to Mo4+ by endogenous glutathione (GSH) depletion, enhancing the cocatalytic effects of MoSe2 and resulting in a continuous Cu+ generation for self-boosting cuproptosis. Meanwhile, GSH-enhanced cocatalysis and MoSe2-mediated photothermal effect can significantly promote Cu-Fenton reactions, which not only downregulate Cu-ATPase to reduce Cu+ efflux and aggravate cuproptosis with higher efficacy but also activate caspase-3 to promote cell apoptosis. MoSe2/CuO2 exhibits excellent antitumor effects (94.9% tumor growth inhibition) and biosafety effects in vitro and in vivo. This work presents a strategy that enables high levels of Cu+ delivery by enhancing generation and reducing efflux for self-boosting cuproptosis-apoptosis synergistic therapy.