Abstract IA25: Tumors alter gut microbiota to suppress immunity and foster progression

Abstract

Abstract Immune dysfunction is commonly observed in patients with cancer contributing to tumor progression. While previous work established a connection between the gut microbiota and the immune system, the mechanisms by which microbiotas contribute to cancer-associated immune dysfunction are not well understood. Using multiple mouse cancer models, we demonstrated robust alterations of gut microbiota in tumor-bearing mice and a substantial change in antimicrobial peptides produced by the gut epithelium. We identified an overall reduction in IFN-γ T cells in tumor-bearing mice, which was rescued with antibiotics treatment or by co-housing tumor-bearing mice with healthy mice. Similar to mouse, we observed changes in gut microbiota and antimicrobial peptides levels of patients diagnosed with ovarian or lung cancer. We identify Firmicutes Ruminococcus members as key promoters of immune dysfunctions and tumor development. These findings identify a new mechanism of immune modulation utilized by tumors to undermine the immune responses and promote tumor progression. Citation Format: Mireia Hribe-Herranz, Kyle Bittinger, Ceylan Tanes, Stavros Rafail, Stefano Pierini, Edgar Ben-Joseph, Janos Tanyi, Andrea Facciabene. Tumors alter gut microbiota to suppress immunity and foster progression [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 IA25.