In situ delivery of Gasdermin E mRNA promotes antitumor immunity via creatine-elicited type Ⅰ interferon signaling in monocytes

Abstract Local immunotherapy stimulates immune responses against tumors while avoiding adverse effects associated with systemic administration. However, current strategies for tumor-targeted in situ immunotherapy are still limited. mRNA-based gene therapy represents a promising strategy. Gasdermin E (GSDME)-mediated pyroptosis is reported to exert anti-tumor immunity. Here, we synthetized mRNA encoding GSDME encapsulated by lipid nanoparticles (LNP-Gsdme). In situ delivery of LNP-Gsdme through intratumoral injection suppressed tumor growth, boosted monocyte infiltration and activated CD8+T cells. LNP-Gsdme induced immunogenic cell death (ICD) in tumor cells, releasing creatine as a metabolic damage-associated molecular pattern. Creatine elicited cGAMP-STING-type I interferon signaling pathway in monocytes and reprogrammed intratumoral monocytes toward an immunostimulatory phenotype, consequently potentiating CD8+T cell-mediated anti-tumor immune responses. Furthermore, creatine supplementation enhanced the antitumor efficacy of LNP-Gsdme. Our study uncovers creatine as an important metabolic biomarker of pyroptosis-induced ICD in tumors, providing new insights and a promising therapeutic approach for in vivo mRNA-based immunotherapies for cancer.