Infection-induced colitis in mice causes dynamic and tissue-specific changes in stress response and DNA damage leading to colon cancer

• Main Authors: Mangerich, Aswin (Contributor), Knutson, Charles G. F. (Contributor), Parry, Nicola Maria Anne (Contributor), Muthupalani, Sureshkumar (Contributor), Ye, Wenjie (Contributor), Prestwich, Erin (Contributor), Cui, Liang (Contributor), McFaline, Jose Luis (Contributor), Mobley, Melissa W. (Contributor), Ge, Zhongming (Contributor), Taghizadeh, Koli (Contributor), Wishnok, John S. (Contributor), Wogan, Gerald N. (Contributor), Fox, James G. (Contributor), Tannenbaum, Steven Robert (Contributor), Dedon, Peter C. (Contributor)
• Other Authors: Massachusetts Institute of Technology. Center for Environmental Health Sciences (Contributor), Massachusetts Institute of Technology. Department of Biological Engineering (Contributor), Massachusetts Institute of Technology. Department of Chemistry (Contributor), Massachusetts Institute of Technology. Division of Comparative Medicine (Contributor), Singapore-MIT Alliance in Research and Technology (SMART) (Contributor)
• Format: Article
• Language: English
• Published: National Academy of Sciences (U.S.), 2013-02-04T20:16:34Z.
• Subjects: Article
• Online Access: Get fulltext

This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1207829109/-/DCSupplemental
Helicobacter hepaticus-infected Rag2-/- mice emulate many aspects of human inflammatory bowel disease, including the development of colitis and colon cancer. To elucidate mechanisms of inflammation-induced carcinogenesis, we undertook a comprehensive analysis of histopathology, molecular damage, and gene expression changes during disease progression in these mice. Infected mice developed severe colitis and hepatitis by 10 wk post-infection, progressing into colon carcinoma by 20 wk post-infection, with pronounced pathology in the cecum and proximal colon marked by infiltration of neutrophils and macrophages. Transcriptional profiling revealed decreased expression of DNA repair and oxidative stress response genes in colon, but not in liver. Mass spectrometric analysis revealed higher levels of DNA and RNA damage products in liver compared to colon and infection-induced increases in 5-chlorocytosine in DNA and RNA and hypoxanthine in DNA. Paradoxically, infection was associated with decreased levels of DNA etheno adducts. Levels of nucleic acid damage from the same chemical class were strongly correlated in both liver and colon. The results support a model of inflammation-mediated carcinogenesis involving infiltration of phagocytes and generation of reactive species that cause local molecular damage leading to cell dysfunction, mutation, and cell death. There are strong correlations among histopathology, phagocyte infiltration, and damage chemistry that suggest a major role for neutrophils in inflammation-associated cancer progression. Further, paradoxical changes in nucleic acid damage were observed in tissue- and chemistry-specific patterns. The results also reveal features of cell stress response that point to microbial pathophysiology and mechanisms of cell senescence as important mechanistic links to cancer.
Cancer Research Institute (CA026731)
National Institute of Environmental Health Sciences (5T32-ES007020-34, Training Grant in Toxicology)
National Institute of Environmental Health Sciences (ES002109)
Massachusetts Institute of Technology (Merck-MIT Fellowship)
German Academic Exchange Service