Clinically, oral fungating lesions frequently occur in cancer patients following radiation and chemotherapy. However, their role in carcinogenesis has not been fully understood. Our previous finding showed that defective IKKα-mediated autoreactive T cells promote fungal infection and esophageal malignancy, but whether IKKα-mediated altered epithelial properties regulate fungal colonization and carcinogenesis remains to be tested. To investigate whether IKKα-mediated altered epithelial properties regulate fungal colonization and carcinogenesis, we orally infected mice lacking Ikkα (IkkαΔSOE) or both Ikkα and Stat3 (IkkαΔSOEStat3ΔSOE) in the stem cells of the skin and mouth with fungi. We found that oral fungal infection enhanced Ikkα ablation-mediated skin and oral carcinogenesis in association with increased oral and skin bacteria counts and altered oral bacteria phylum from gram-positive to gram-negative. Enhanced oral fungal/bacterial infection increased inflammasome activities and systemic IL-17A/IL-1β signals. Surprisingly, Stat3 ablation rescued these phenotypes in IkkαΔSOEStat3ΔSOE mice. In addition, amoxicillin treatment inhibited skin carcinogenesis and oral/skin bacteria counts and reversed oral bacteria phyla in fungal-inoculated IkkαΔSOE mice. These findings highlight that cancer cell IKKα/STAT3 antagonizing pathways determine susceptibility to fungal and bacterial colonization, which impacts carcinogenesis. Human head and neck squamous cell carcinomas also share oncogenic pathways and bacteria sequences/counts with mice, suggesting that oral fungating/ulcerating lesions enhance local and distal tumorigenesis in humans.

Citation Format: Na-Young Song, Xin Li, Jonathan H. Badger, Jami Willette Brown, Xhonghe Sun, Gongping Shi, Feng Zhu, Chengfei Jiang, Colum O'hUigin, Xiaolin Wu, Giorgio Trinchieri, Yinling Hu. IKKα/STAT3 antagonistic signaling regulates fungi-bacteria endosymbiosis-associated carcinogenesis [abstract]. In: Proceedings of the AACR Special Conference on the Microbiome, Viruses, and Cancer; 2020 Feb 21-24; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2020;80(8 Suppl):Abstract nr B17.