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Polymethoxyflavones prevent benzo[ a ]pyrene/dextran sodium sulfate‐induced colorectal carcinogenesis through modulating xenobiotic metabolism and ameliorate autophagic defect in ICR mice
Author(s) -
Wu JiaChing,
Tsai MeiLing,
Lai ChingShu,
Lo ChihYu,
Ho ChiTang,
Wang YingJan,
Pan MinHsiung
Publication year - 2017
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.31190
Subject(s) - carcinogen , benzo(a)pyrene , carcinogenesis , chemistry , cancer research , gut flora , biochemistry , pharmacology , biology , gene
Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental carcinogenic pollutants and they have become an important issue in food contamination. Dietary intake of PAHs has been recognized as a major route of human exposure. However, the mechanisms behind dietary PAH‐induced colorectal cancer (CRC) remain unclear. Several studies have shown that polymethoxyflavones (PMFs) are effective in preventing carcinogen‐induced CRC or colitis. In this study, we investigated the preventive effect of PMFs on benzo[ a ]pyrene/dextran sulfate sodium (B a P/DSS)‐induced colorectal tumorigenesis in ICR mice. We found that PMFs significantly prevented B a P/DSS‐induced colorectal tumor formation. B a P mutagenic metabolite and DNA adducts were found to be reduced in colonic tissue in the PMFs‐treated groups through the modulation of B a P metabolism. At the molecular level, the results of RNA‐sequencing indicated that PMFs ameliorated B a P/DSS‐induced abnormal molecular mechanism change including activated inflammation, downregulated anti‐oxidation targets, and induced metastasis genes. The autophagic defect caused by B a P/DSS‐induced tumorigenesis was improved by pretreatment with PMFs. We found B a P/DSS‐induced CRC may be a Wnt/β‐catenin independent process. Additionally, consumption of PMFs extracts also altered the composition of gut microbiota and made it similar to that in the control group by increasing butyrate‐producing probiotics and decreasing CRC‐related bacteria. B a P in combination with DSS significantly induced colorectal tumorigenesis through induced DNA adduct formation, abnormal gene expression, and imbalanced gut microbiota composition. PMFs were a powerful preventive agent that suppressed B a P/DSS‐induced CRC via modulating multiple pathways as well as ameliorating autophagic defect. These results demonstrated for the first time the chemopreventive efficacy and comprehensive mechanisms of dietary PMFs for preventing B a P/DSS‐induced colorectal carcinogenesis.