title: Curcumin ameliorates the tumor-enhancing effects of a high-protein diet in an azoxymethane-induced mouse model of colon carcinogenesis.
abstract: An increasing number of reports suggest that a high-protein diet (HPD) is associated with an increased risk for colorectal cancer (CRC). One of the proposed mechanisms is that an HPD increases the delivery of protein to the colon and generates various toxic metabolites that contribute to colon carcinogenesis. Curcumin was shown to exert significant preventive properties against CRC. We therefore hypothesized that curcumin can reverse the tumor-enhancing effects of an HPD. This study examined the effects of curcumin on the development of azoxymethane (AOM)-induced colorectal tumors in HPD-fed mice. A total of 30 female Balb/c mice were randomly divided into 3 groups: those fed a normal diet (20% casein), those fed an HPD (HPD; 50% casein), and those fed an HPD supplemented with curcumin (HPDC; 0.02% curcumin). The mice were subjected to an AOM-dextran sodium sulfate colon carcinogenesis protocol. Mice in the HPDC group exhibited a significant (40%) reduction in colorectal tumor multiplicity when compared with those in the HPD group. The expression of colonic inflammatory proteins (cyclooxygenase-2 and inducible nitric oxide synthase), the levels of plasma inflammatory markers (nitric oxide and tumor necrosis factor-α), fecal ammonia, short- and branched-chain fatty acid levels, and the rate of colonocyte proliferation were significantly lower in the HPDC than the HPD group. In conclusion, curcumin inhibited the development of colorectal tumors in an AOM-induced mouse model of colon carcinogenesis by attenuating colonic inflammation, proliferation, and toxic metabolite production. Curcumin might be useful in the chemoprevention of CRC in individuals consuming an HPD.
authors.affiliation: Department of Food Science and Nutrition, Catholic University of Daegu, Gyeongsan, Korea.
authors.forename: So-Young
authors.initials: SY
authors.lastname: Byun
authors.affiliation: Department of Food Science and Nutrition, Catholic University of Daegu, Gyeongsan, Korea.
authors.forename: Dan-Bi
authors.initials: DB
authors.lastname: Kim
authors.affiliation: Department of Food Science and Nutrition, Catholic University of Daegu, Gyeongsan, Korea. Electronic address: kimeunj@cu.ac.kr.
authors.forename: Eunjung
authors.initials: E
authors.lastname: Kim
mesh_terms: D000641:Ammonia / Q000378:metabolism; D000818:Animals; D001397:Azoxymethane; D063646:Carcinogenesis / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D003106:Colon / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D003110:Colonic Neoplasms / Q000139:chemically induced / Q000188:drug therapy*; D003474:Curcumin / Q000494:pharmacology*; D051546:Cyclooxygenase 2 / Q000235:genetics / Q000378:metabolism; D004032:Diet; D004044:Dietary Proteins / Q000009:adverse effects*; D005227:Fatty Acids / Q000032:analysis; D005243:Feces / Q000737:chemistry; D005260:Female; D051379:Mice; D008807:Mice, Inbred BALB C; D009569:Nitric Oxide / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000235:genetics / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D004044:Dietary Proteins; D005227:Fatty Acids; D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide; D000641:Ammonia; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; C077623:Ptgs2 protein, mouse; D051546:Cyclooxygenase 2; D003474:Curcumin; D001397:Azoxymethane
keywords: Colorectal cancer; Curcumin; Dietary protein; Inflammation; Mouse