Cd73-LNPs promotes antitumor T-cell immunity via amplifying Tlr3-mediated immunostimulatory dendritic cell activation

Background: mRNA vaccines have emerged as highly promising therapeutic agents in the field of cancer immunotherapy. Nevertheless, the current limited immunogenicity of target antigens, along with a lack of systemic immune response, poses significant challenges to the effective implementation of mRNA vaccines. This study sought to evaluate the immunogenicity of the Cd73 protein and elucidate the mechanisms through which the Cd73 mRNA vaccines mediated its antitumor immune effects in murine models. Methods: In vitro transcription synthesis of Cd73 mRNA was employed to prepare a Cd73 mRNA vaccine based on lipid nanoparticles (Cd73-LNPs) using a microfluidic device. The immunogenicity of Cd73 was assessed via ELISPOT assays. The capability of Cd73-LNPs to activate anti-tumor immune responses was investigated via flow cytometry. The therapeutic efficacy of Cd73-LNPs was tested in models of melanoma, cervical cancer, ovarian cancer, and prostate cancer. Furthermore, the mechanism of action of Cd73-LNPs was elucidated through single-cell transcriptomics sequencing and RNA transcriptomics sequencing. Results: The Cd73 protein exhibited potent immunogenicity. In vitro, Cd73-LNPs have been observed to promote the maturation and activation of primary dendritic cells. In vivo, they have been observed to activate both humoral and cellular immune responses, stimulating secretion of Ifn-γ and granzyme B, effectively suppressing tumor growth in models of melanoma, cervical cancer, ovarian cancer, and prostate cancer. Mechanistically, Cd73-LNPs activate dendritic cells through toll-like receptor 3 signaling, enhancing their activation and upregulating chemokine receptor expression on Cd8 ⁺ T cells, which promotes Cd8 ⁺ T cell infiltration into the tumor microenvironment. Safety evaluations revealed that Cd73-LNPs do not produce toxic side effects on vital organs. Conclusion: Cd73 mRNA vaccines have been demonstrated to safely and effectively induce antitumor immunity through toll-like receptor 3 signaling, indicating considerable potential for clinical application.