title: Chlorinated Water Modulates the Development of Colorectal Tumors with Chromosomal Instability and Gut Microbiota in Apc-Deficient Mice.
abstract: The gastrointestinal tract is continuously exposed to a variety of chemicals and commensal bacteria. Recent studies have shown that changes in gut microbial populations caused by chlorine or other chemicals in the drinking water influence the development of human colorectal cancer, although the mechanism of tumorigenesis in the gut epithelium is obfuscated by the diversity of microflora and complexity of the tumor microenvironment. In this regard, mouse models that recapitulate human colorectal cancer are an invaluable tool. In this study, we used two conditional adenomatous polyposis coli (Apc) knockout mouse models to investigate the effect of chlorinated water on tumorigenesis in the digestive tract. Mice with colon-specific carcinoma--caused by either chromosomal (CDX2P 9.5-NLS Cre;Apc(+/flox), abbreviated to CPC;Apc) or microsatellite (CDX2P9.5-G19Cre;Apc(flox/flox) and CDX2P9.5-G22Cre;Apc(flox/flox)) instability, respectively--were administered chlorinated (10.0 mg/L chlorine) or tap (0.7 mg/L chlorine) water and evaluated for colon polyp formation. In CPC;Apc mice given chlorinated drinking water, tumors tended to develop in the colon, whereas in those that drank tap water, tumors were mostly observed in the small intestine. There was no difference in the rate of tumor formation of CDX2P9.5-G19Cre;Apc(flox/flox) and CDX2P9.5-G22Cre;Apc(flox/flox) mice consuming chlorinated as compared to tap water, suggesting that microsatellite instability in the Apc gene does not significantly affect tumorigenesis. Chlorinated water altered the enteric environment by reducing the fecal populations of the obligatory anaerobes Clostridium perfringens and C. difficile, as well as species belonging to the Atopobium cluster, including Enterobacteriaceae and Staphylococcus sp., which was associated with colon tumorigenesis in CPC;Apc mice. These results suggest that differences in tumorigenesis among CPC;Apc mice consuming chlorinated versus tap water may be due to differences in gastrointestinal commensal populations.
authors.affiliation: Department of Gastroenterological and Transplant Surgery, Applied Life Science, Institute of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan.
authors.forename: Tatsunari
authors.initials: T
authors.lastname: Sasada
authors.affiliation: Department of Gastroenterological and Transplant Surgery, Applied Life Science, Institute of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan.
authors.forename: Takao
authors.initials: T
authors.lastname: Hinoi
authors.affiliation: Department of Gastroenterological and Transplant Surgery, Applied Life Science, Institute of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan.
authors.forename: Yasufumi
authors.initials: Y
authors.lastname: Saito
authors.affiliation: Department of Gastroenterological and Transplant Surgery, Applied Life Science, Institute of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Adachi
authors.affiliation: Department of Gastroenterological and Transplant Surgery, Applied Life Science, Institute of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Takakura
authors.affiliation: Department of Gastroenterological and Transplant Surgery, Applied Life Science, Institute of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan.
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Kawaguchi
authors.affiliation: Natural Science Center for Basic Research and Development, Hiroshima University, Hiroshima, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Sotomaru
authors.affiliation: Department of Molecular Pathology, Hiroshima University Institute of Biomedical and Health Sciences, Hiroshima, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Sentani
authors.affiliation: Department of Molecular Pathology, Hiroshima University Institute of Biomedical and Health Sciences, Hiroshima, Japan.
authors.forename: Naohide
authors.initials: N
authors.lastname: Oue
authors.affiliation: Department of Molecular Pathology, Hiroshima University Institute of Biomedical and Health Sciences, Hiroshima, Japan.
authors.forename: Wataru
authors.initials: W
authors.lastname: Yasui
authors.affiliation: Department of Gastroenterological and Transplant Surgery, Applied Life Science, Institute of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Ohdan
mesh_terms: D025601:Adenomatous Polyposis Coli Protein / Q000172:deficiency* / Q000235:genetics; D000818:Animals; D063646:Carcinogenesis / Q000187:drug effects* / Q000235:genetics / Q000473:pathology; D002713:Chlorine / Q000494:pharmacology*; D043171:Chromosomal Instability; D016360:Clostridioides difficile / Q000187:drug effects / Q000254:growth & development; D003016:Clostridium perfringens / Q000187:drug effects / Q000254:growth & development; D003106:Colon / Q000187:drug effects / Q000382:microbiology / Q000473:pathology; D003110:Colonic Neoplasms / Q000139:chemically induced* / Q000235:genetics / Q000382:microbiology / Q000473:pathology; D004195:Disease Models, Animal; D060766:Drinking Water / Q000737:chemistry*; D004755:Enterobacteriaceae / Q000187:drug effects / Q000254:growth & development; D005260:Female; D000069196:Gastrointestinal Microbiome / Q000187:drug effects* / Q000502:physiology; D015870:Gene Expression; D054879:Halogenation; D006801:Humans; D007421:Intestine, Small / Q000187:drug effects / Q000382:microbiology / Q000473:pathology; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D018895:Microsatellite Repeats; D013210:Staphylococcus / Q000187:drug effects / Q000254:growth & development
chemical_list: D025601:Adenomatous Polyposis Coli Protein; D060766:Drinking Water; D002713:Chlorine