Tumor-associated macrophage-derived itaconic acid contributes to nasopharyngeal carcinoma progression by promoting immune escape via TET2.

Nasopharyngeal carcinoma (NPC) is a malignant tumor of epithelial origin in head and neck with high incidence rate in South China, Southeast Asia and North Africa. The intervention of tumor-associated macrophages (Mφs) (TAMs)-mediated immunosuppression is a potential therapeutic strategy against tumor metastasis, but the exact mechanisms of TAM-mediated immunosuppression in nasopharyngeal carcinoma are unclear. Furthermore, how TAM affects the occurrence and development of nasopharyngeal carcinoma through metabolism is rarely involved. In this work, we revealed that NPC cells promoted M2-type Mφ polarization and elevated itaconic acid (ITA) release. Also, TAMs facilitated NPC cell proliferation, migration, and invasion through immune response gene 1 (IRG1)-catalyzed ITA production. Then, IRG1-mediated ITA production in TAMs repressed the killing of CD8 T cells, induced M2-type polarization of TAMs, and reduced the phagocytosis of TAMs. Moreover, we demonstrated ITA played a tumor immunosuppressive role by binding and dampening ten-eleven translocation-2 (TET2) expression. Finally, we proved that ITA promotes NPC growth by facilitating immune escape in CD34 hematopoietic stem cell humanized mice. In Conclusion, TAM-derived ITA facilitated NPC progression by enhancing immune escape through targeting TET2, highlighting that interfering with the metabolic pathway of ITA may be a potential strategy for NPC treatment.