Remodeling of Tumor Microenvironment by Nanozyme Combined cGAS-STING Signaling Pathway Agonist for Enhancing Cancer Immunotherapy.

Nanozymes and cyclic GMP-AMP synthase (cGAS) the stimulator of interferon genes (STING) signaling pathway, as powerful organons, can remodel the tumor microenvironment (TME) to increase efficacy and overcome drug resistance in cancer immunotherapy. Nanozymes have the potential to manipulate the TME by producing reactive oxygen species (ROS), which lead to positive oxidative stress in tumor cells. Cyclic dinucleotide (2',3'-cGAMP), as a second messenger, exists in the TME and can regulate it to achieve antitumor activity. In this work, Co,N-doped carbon dots (CoNCDs) were used as a model nanozyme to evaluate the properties of the anti-tumor mechanism, and effective inhibition of S180 tumor was achieved. Based on CoNCDs' good biocompatibility and therapeutic effect on the tumor, we then introduced the cGAS-STING agonist, and the combination of the CoNCDs and STING agonist significantly inhibited tumor growth, and no significant systemic toxicity was observed. The combined system achieved the enhanced tumor synergistic immunotherapy through TME reprogramming via the peroxidase-like activity of the CoNCDs and cGAS-STING signaling pathway agonist synergistically. Our work provides not only a new effective way to reprogram TME in vivo, but also a promising synergic antitumor therapy strategy.