title: Inflammation enhanced X-irradiation-induced colonic tumorigenesis in the Min mouse.
abstract: Inflammation is potential risk factor of various human malignancies. Inflammatory bowel syndromes such as ulcerative colitis are well known as risk factors for colon cancer. Here, we examined enhancing effects of dextran sulfate sodium (DSS)-associated inflammation on X-irradiation induced colonic tumorigenesis in Min and wild-type (WT) mice. Animals were X-irradiated at 1.5 Gy at 5 weeks of age (at 0 experimental week) and 2% DSS in drinking water was administered at 5 or 11 experimental weeks. Mice were sacrificed at 16 weeks and incidence and multiplicity of colonic tumors were assessed. Incidence of colonic tumors in Min mouse was increased from 33.3% to 100% (p<0.05) with X-irradiation alone, whereas no tumors were developed in WT mice. In DSS-treated Min mice, X-irradiation increased the number of colonic tumors. Total number of colonic tumors was increased 1.57 times to 30.7±3.83 tumors/mouse with X-irradiation+DSS at 5 weeks comapared to 19.6±2.9 in corresponding DSS alone group (p<0.05). When the duration of inflammation was compared, longer period of DSS effect promoted more colonic tumorigenesis. Collectively, we conclude that X-irradiation and DSS-induced inflammation act synergistically for colonic tumorigenesis.
authors.affiliation: Division of Oncological Pathology, Aichi Cancer Center Research Institute, Nagoya, Japan.
authors.forename: Ayumi
authors.initials: A
authors.lastname: Nojiri
authors.forename: Takeshi
authors.initials: T
authors.lastname: Toyoda
authors.forename: Takuji
authors.initials: T
authors.lastname: Tanaka
authors.forename: Toshimichi
authors.initials: T
authors.lastname: Yoshida
authors.forename: Masae
authors.initials: M
authors.lastname: Tatematsu
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Tsukamoto
mesh_terms: D000230:Adenocarcinoma / Q000209:etiology* / Q000473:pathology; D025601:Adenomatous Polyposis Coli Protein / Q000502:physiology*; D000818:Animals; D002471:Cell Transformation, Neoplastic / Q000187:drug effects / Q000473:pathology* / Q000528:radiation effects; D003092:Colitis / Q000150:complications* / Q000473:pathology; D003110:Colonic Neoplasms / Q000209:etiology* / Q000473:pathology; D016264:Dextran Sulfate / Q000633:toxicity; D004195:Disease Models, Animal; D005260:Female; D006801:Humans; D007249:Inflammation / Q000150:complications* / Q000473:pathology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D014965:X-Rays / Q000009:adverse effects*
chemical_list: D025601:Adenomatous Polyposis Coli Protein; D016264:Dextran Sulfate