Delivery of IL-12 by neoantigen-reactive T cells promotes antitumor immunity in murine osteosarcoma mode.

Purpose: Despite the proven clinical benefits of cytokine therapy in cancer treatment, systemic administration of cytokines such as IL-12 is constrained by dose-limiting toxicities and short half-lives. To address these challenges, we explored a localized cytokine delivery strategy using engineered neoantigen-reactive T (NRT) cells as carriers in a murine model of osteosarcoma.

Materials and methods: We used a neoantigen from K7M2 osteosarcoma cells to retrovirally transduce NRT cells to express an inducible form of IL-12. We evaluated the engineered NRT cells' antitumor activity and the production of IL-12 and IFN-γ upon in vitro co-culture with tumor cells. We systemically administered NRT-IL-12 cells in a mouse model of osteosarcoma to assess their impact on tumor growth and survival.

Results: In vitro assays demonstrated that the engineered NRT cells exhibited enhanced antitumor activity and produced elevated levels of IL-12 and IFN-γ. In the mouse model of osteosarcoma, systemic administration of NRT-IL-12 cells resulted in a significant reduction in tumor growth and an increase in survival rates compared to the administration of control NRT cells. Further analysis revealed that NRT-IL-12 cells induced a profound increase in CD8+ T-cell infiltration and a decrease in Treg cells within the tumor microenvironment.

Conclusion: Our study presents a novel and efficacious strategy for osteosarcoma immunotherapy by harnessing NRT cells as targeted cytokine delivery vehicles.