Abstract LB278: IL-12 immunotherapy prevents hepatocellular carcinoma in a murine NAFLD induced cirrhosis model

• Published in: Cancer research (Chicago, Ill.) Ill.), 2023-04, Vol.83 (8_Supplement), p.LB278-LB278
• Main Authors: Sojoodi, Mozhdeh, Barrett, Stephen C., Erstad, Derek J., Jordan, Veronica Clavijo, Gale, Eric M., Salloum, Shadi, Wang, Yongtao, Lanuti, Michael, Zukerberg, Lawrence, Caravan, Peter, Lauer, Georg M., Tanabe, Kenneth K.
• Format: Article
• Language: English
• ISSN: 1538-7445; 1538-7445
• DOI: 10.1158/1538-7445.AM2023-LB278

Introduction: Interleukin 12 (IL-12) is an important bridge between the innate and adaptive immune systems. It is mainly produced by macrophages and can bind to its receptor (IL12R) on T cells. It affects several aspects of T cell activation, including IFN-γ and perforin production. Tumor-infiltrating CD8+ T cells perform important anti-tumoral actions, which need to be overcome to allow cancer cell growth. This work studied IL-12 administration as an HCC preventive strategy in cirrhotic mice. We investigated whether IL-12 can boost the recruitment of macrophages to the liver, increase their antigen-presenting ability, and activate cytolytic T cells to inhibit HCC development in cirrhotic livers. Method: 8 weeks old mice were fed a choline-deficient High fat diet (CDAHFD) for 16 weeks to create NAFLD-induced HCC. A subset of CDAHFD mice was injected intravenously with IL-12 (0.5mg/gr) weekly from 12 to 16 weeks. Mice were euthanized after 16 weeks, and liver and serum were collected for further analysis. Results: After tissue collection, we observed that 50% of untreated animals developed HCC lesions, while IL-12-treated mice did not have any HCC. After treatment with IL12, qPCR and western blot on total liver tissue showed up-regulation in the IL12 receptor and activation of the IL-12 pathway, evidenced by the increase in Stat4 expression and phosphorylation. Additionally, we detected an increase in IFN-γ expression by qPCR in IL-12-treated mice. Histological analysis showed a significant decrease in fat and collagen deposition in IL-12-treated livers compared to untreated livers. IL-12-treated mice had lower serum aminotransferase enzymes (AST & ALT), indicating improved liver function. Immunostaining and flow cytometry of F4/80 (macrophage marker) showed an increase in the number of macrophages in the livers treated with IL-12. Flow cytometry data showed that the majority of macrophages present in the IL-12 livers were CCR2+, a marker for recruited macrophages. Notably, IL-12-treated macrophages expressed more MHCII (antigen presentation marker) and less B7H4 (inhibitory marker). In addition, we observed a significant increase in the number of cytolytic T cells (CD8+) in the IL-12 treated livers, which had higher expression of the T cell activation marker (CD25) and elevated levels of perforin and IFN-γ that are nessacery for their cytotoxic activity. Conclusion: There is a lack of substantial evidence to describe the underlying mechanisms supporting th