title: Linking inflammation to tumorigenesis in a mouse model of high-fat-diet-enhanced colon cancer.
abstract: Many observational epidemiologic studies suggest an association between high-fat-diet (HFD) and colon cancer risk. However, the lack of controlled experimental studies that examine this relationship and the mechanisms involved weaken the basis for inferring a causal relationship. Inflammation plays a role in colon cancer progression and HFDs have been reported to increase inflammation; however, the inflammatory effects of HFD in colon cancer have yet to be firmly established. We examined the effects of a novel HFD that closely mimics the standard American diet (12% and 40% of total caloric intake from saturated fat and total fat, respectively) on macrophage markers and inflammatory mediators in a mouse model of intestinal tumorigenesis and relate this to polyp characteristics as well as measures of adiposity. Male Apc(Min/+) mice (7-8/group) were fed a Control Diet (Con) or novel high-fat-diet (HFD) from 4 to 12weeks of age. Body weight and body composition were measured weekly and monthly, respectively. Intestinal tissue was analyzed for polyp burden (number and size). Gene expression of macrophage markers and inflammatory mediators were examined in the adipose tissue and polyps. The HFD increased the expression of macrophage markers and inflammatory mediators in the adipose tissue (F4/80, CD11c, TLR-4 and MCP-1) and tumor microenvironment (IL-12, MCP-1, IL-6 and TNF-α). As expected, the HFD increased body weight, body fat percent, fat mass and blood glucose (P<0.05), and was associated with an increase in the number of large polyps (P<0.05) but not total polyps. In summary, consumption of a HFD, similar in macronutrient composition to the standard American diet, altered the expression of macrophage phenotypic markers and inflammatory mediators in adipose tissue and intestinal polyps and this was associated with increased tumorigenesis.
authors.affiliation: Department of Pathology, Microbiology & Immunology, School of Medicine, University of South Carolina, Columbia, SC 29209, USA. Electronic address: sgilmer@erskine.edu.
authors.forename: Stani D
authors.initials: SD
authors.lastname: Day
authors.forename: Reilly T
authors.initials: RT
authors.lastname: Enos
authors.forename: Jamie L
authors.initials: JL
authors.lastname: McClellan
authors.forename: J L
authors.initials: JL
authors.lastname: Steiner
authors.forename: Kandy T
authors.initials: KT
authors.lastname: Velázquez
authors.forename: E A
authors.initials: EA
authors.lastname: Murphy
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism; D000818:Animals; D000943:Antigens, Differentiation / Q000378:metabolism; D015415:Biomarkers / Q000378:metabolism; D001786:Blood Glucose; D001823:Body Composition; D001835:Body Weight; D039521:CD11c Antigen / Q000378:metabolism; D063646:Carcinogenesis / Q000276:immunology*; D018932:Chemokine CCL2 / Q000378:metabolism; D003110:Colonic Neoplasms / Q000209:etiology*; D003111:Colonic Polyps / Q000378:metabolism*; D004032:Diet; D059305:Diet, High-Fat; D015870:Gene Expression; D007249:Inflammation / Q000276:immunology*; D018836:Inflammation Mediators / Q000378:metabolism; D018664:Interleukin-12 / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D008264:Macrophages / Q000276:immunology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D051197:Toll-Like Receptor 4 / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D000943:Antigens, Differentiation; D015415:Biomarkers; D001786:Blood Glucose; D039521:CD11c Antigen; C491768:Ccl2 protein, mouse; D018932:Chemokine CCL2; D018836:Inflammation Mediators; D015850:Interleukin-6; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; D014409:Tumor Necrosis Factor-alpha; C036763:monocyte-macrophage differentiation antigen; D018664:Interleukin-12
keywords: High-fat-diet; Inflammation; Intestinal tumorigenesis; Macrophages; Obesity