Genetically modified extracellular vesicles loaded with activated gasdermin D potentially inhibit prostate-specific membrane antigen-positive prostate carcinoma growth and enhance immunotherapy

Prostate cancer (PCa) is associated with poor immunogenicity and lymphocytic infiltration, and immunotherapy effective against PCa remains unavailable. Pyroptosis, a novel immunotherapeutic modality for cancer, promotes systemic immune responses leading to immunogenic cell death in solid tumors. This paper describes the preparation and analysis of PSMA_scFv-EV^N-GSDMD; this genetically engineered recombinant extracellular vesicle (EV) expresses a single-chain variable antibody fragment (scFv) with high affinity for prostate-specific membrane antigen (PSMA) on their surfaces and is loaded with the N-terminal domain of gasdermin D (GSDMD). Both in vitro and in vivo, PSMA_scFv-EV^N-GSDMD effectively targeted PSMA-positive PCa cells and induced pyroptosis through the carrier properties of EVs and the specificity of PSMA_scFv. In the 22RV1 and PSMA-transfected RM-1-inoculated PCa mouse models, PSMA_scFv-EV^N-GSDMD efficiently inhibited tumor growth and promoted tumor immune responses. In conclusion, PSMA_scFv-EV^N-GSDMD can convert the immunosuppressive "cold" tumor microenvironment of PCa into an immunogenic "hot" tumor microenvironment.