Engineered Cryo-Shocked Cancer Cells Deliver Dual-Function Gene Medicines for Melanoma Immunotherapy

Immunotherapies for melanoma are frequently hindered by resistance to immune checkpoint blockade and poor infiltration of T cells into the tumor microenvironment (TME). To overcome these limitations, a novel dual-function plasmid is designed, termed CXCL9-ABE_PCSK9, that combines adenine base editing to knock down PCSK9 (a newly identified immunosuppressive factor that impairs CD8⁺ T cell activity) with overexpression of the chemokine CXCL9, known for its role in recruiting T cells. The plasmid is first encapsulated into a liposome and then loaded on the liquid nitrogen-treated (LNT) tumor cells, generating LNT@LipoC9AP particles. These LNT cells maintain structural integrity and tumor-homing properties, functioning as a "Trojan horse" delivery system, while losing pathogenicity. It is find that LNT@LipoC9AP effectively increased CD8⁺ T cell tumor infiltration and exhibited potent antitumor effects in vitro and in vivo. To further improve tumor targeting, LNT@LipoC9AP is engineered by decorating the LNT cell surface with RGD4C peptides, yielding R-LNT@LipoC9AP, which targets αvβ3 integrins commonly overexpressed in melanoma. R-LNT@LipoC9AP demonstrated superior tumor accumulation, enhanced therapeutic efficacy, and a favorable safety profile. Altogether, the LNT cell-based co-delivery system for CXCL9 and ABE_PCSK9 overcomes the limitations of current tumor immunotherapy and may serve as a promising gene therapy strategy for solid tumors treatment.