Antineoplastic Enzyme As Drug Carrier with Activatable Catalytic Activity for Efficient Combined Therapy

The delivery of glucose oxidase (GOx) requires extra carriers, which suffers from early leakage and exposure of GOx. These issues will be of less concern if GOx itself acts as a drug carrier. However, the catalytic activity of GOx in the blood still needs to be inhibited. Herein, we found that GOx could self-assemble with hydrophobic molecules into uniform and stable nanoparticles (NPs), including sorafenib, 4'-(amino-methyl phenyl)-2,2' : 6',2''-terpyridine modified cyanin and paclitaxel. The catalytic activity of GOx in NPs was significantly inhibited due to the binding of small molecules with its hydrophobic pockets. After dissociation in the tumor acidic microenvironment, the enzyme activity of GOx could be largely recovered. This acidity-triggered "OFF-to-ON" process ensured safe intravenous administration of GOx-based NPs. In vivo experiments showed that the combined starvation therapy and ferroptosis/photothermal therapy/chemotherapy effectively inhibited 4T1 breast tumor growth.