Administration of lipid nanoparticle-encapsulated mRNA encoding CCR7, CXCL16 and GITRL effectively mobilizes antitumor T cell immunity.

The insufficient activation, infiltration, and functional suppression of tumor-killing cells in the tumor microenvironment (TME) collectively hinder antitumor immunity. CCR7, CXCL16, and GITRL are well-established immune modulators with potential to enhance immunotherapy efficacy. Herein, we developed lipid nanoparticle-encapsulated mRNA (LNP-mRNA) encoding these three targets with the aim of enhancing dendritic cell (DC) immunogenicity and improving the immunosuppressive TME. DCs were stimulated in vitro with LNP-mRNA to evaluate its effects on DC function. The systemic immune response of LNP-mRNA was characterized. To assess the antitumor effect of LNP-mRNA, B16-OVA tumor-bearing mouse models were constructed. Humanized Raji-engrafted mouse models were constructed to investigate the synergistic effect of LNP-mRNA and anti-PD-1 antibody. Results demonstrated that LNP-mRNA enhanced the function of DCs. Furthermore, LNP-mRNA promoted T cell activation and effector differentiation while suppressing regulatory T cell infiltration. Intratumoral administration of LNP-mRNA elicited potent immune response and induced regression of established tumors. In humanized Raji-engrafted mouse models, the combination use of LNP-mRNA and anti-PD-1 antibody synergistically amplified antitumor immunity. Overall, our research demonstrates that the synthesized LNP-mRNA enables durable tumor control through coordinated enhancement of DC functionality, T cell priming, and immunosuppressive TME remodeling. This multi-functional strategy marks a transformative advancement in tumor immunotherapy.