Multienzymatic Hybrid Metalloenzymes Triggering Cascade Reactions-Regulated Tumor Redox Homeostasis and Immunosuppressive Microenvironment for Catalytic Immunotherapy.

Artificial multienzyme systems hold promise for tumor catalytic immunotherapy by a cascade catalyzing the generation of reactive oxygen species (ROS). However, the intricate redox homeostasis restricts ROS accumulation coupled with the immunosuppressive tumor microenvironment (TME), resulting in unsatisfactory therapeutic efficacy. Developing multienzyme systems that can overcome multifaceted TME limitations for effective catalytic immunotherapy is still a significant challenge. Inspired by natural metalloenzymes, herein, a synergistic multienzyme nanoplatform (Co3S4@LOx/HA) is constructed by integrating mixed-valent cobalt sulfide (Co3S4) nanozymes as artificial cofactors and lactate oxidase (LOx) as protein scaffolds, encapsulated with hyaluronic acid (HA). Through self-cyclic cascade catalysis involving multienzyme activities (LOx, catalase-like, peroxidase-like, and glutathione peroxidase-like activities), Co3S4@LOx/HA can concurrently facilitate H2O2 and •OH generation and deplete intracellular glutathione (GSH). Moreover, Co3S4@LOx/HA can also inhibit endogenous thioredoxin reductase (TrxR) activity by the acidic TME-responsive release of hydrogen sulfide (H2S), further disrupting intracellular redox homeostasis. As a result, the significantly amplified ROS increased double-stranded DNA damage and leakage, thereby activating the stimulator of interferon genes (STING)-related immune responses. Additionally, lactate consumption and O2 generation during catalytic processes remodeled the immunosuppressive TME. Overall, Co3S4@LOx/HA is the first multienzyme nanoplatform that can simultaneously modulate multiple redox homeostasis and the immunosuppressive TME for precise and efficient tumor catalytic immunotherapy. This biomimetic metalloenzyme strategy will inspire more innovative designs of multienzyme nanoplatforms for ROS-mediated tumor therapies.