Co-delivery of SN38 and SR717 activates cGAS-STING for near-infrared II image-guided chemoimmunotherapy

DNA-targeting chemotherapies can activate the stimulator of interferon genes (STING) pathway but elicit limited immune responses. We engineered 3P-SN38, a long-circulating nanoplatform enabling sustained, tumor-targeted SN38 delivery and NIR-II imaging. To further potentiate immune activation and minimize STING agonist toxicity, SR717 was co-encapsulated, forming 3P-SN38@SR717. 3P-SN38@SR717 induced immunogenic cell death and dendritic cell maturation in vitro, with combination therapy showing superior effects. In vivo, 3P-SN38@SR717 effectively activated the cGAS-STING pathway, enhancing anti-tumor immunity. Significant increases in the populations of CD8⁺ T cells, mature dendritic cells, and M1-type macrophages were observed, along with elevated levels of cytokines, including IL-6 and TNF-α. This integrated nanoplatform offers a promising approach for chemoimmunotherapy, enabling durable tumor control with reduced dosing and improved safety.