Conclusion
Our strategy highlights the potency of AUG as a neoadjuvant paradigm for presurgical tumor debulking and as a preventive measure against postoperative tumor recurrence and metastasis.
Methods
We devise a hierarchically unlocking nanoSTING stimulant liposome (AUG) as a neoadjuvant chemoimmunotherapy agent in the debulking of tumors prior to surgery and prevention of postoperative tumor recurrence and metastasis by simultaneously activating innate and adaptive antitumor immune responses. In the weakly acidic tumor microenvironment, the hydrazone bond within AUG is initially cleaved, leading to the release of a cyclic seven-membered ring containing tertiary amine that serve to activate the stimulator of interferon genes (STING) pathway. Following this, AUG undergoes degradation within lysosomes, facilitating the release of doxorubicin and ultimately inducing immunogenic cell death along with leakage of double-stranded DNA into the cytoplasm.
Results
The hierarchically acidity-unlocking pattern enables cascaded STING activation, achieving over 90% tumor growth inhibition in subcutaneous xenograft model and preventing 75% of mice from postsurgical metastasis or recurrence when combined with immune checkpoint inhibitors.