Polymethoxyflavones prevent benzo[a]pyrene/dextran sodium sulfate‐induced colorectal carcinogenesis through modulating xenobiotic metabolism and ameliorate autophagic defect in ICR mice |
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| Authors: | Jia‐Ching Wu Mei‐Ling Tsai Ching‐Shu Lai Chih‐Yu Lo Chi‐Tang Ho Ying‐Jan Wang Min‐Hsiung Pan |
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| Affiliation: | 1. Department of Environmental and Occupational Health, College of Medicine, National Cheng Kung University, Tainan, Taiwan;2. Department of Seafood Science, National Kaohsiung Marine University, Kaohsiung, Taiwan;3. Department of Food Science, National Chiayi University, no. 300 Syuefu Road, Chiayi, Taiwan;4. Department of Food Science, Rutgers University, New Brunswick, NJ;5. Department of food safety/Hygiene and risk management, College of Medicine, National Cheng Kung University, Tainan, Taiwan;6. Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan;7. Department of Medical Research, China Medical University Hospital, China Medical University, Taichung, Taiwan;8. Department of Health and Nutrition Biotechnology, Asia University, Taichung, Taiwan;9. Institute of Food Science and Technology, National Taiwan University, Taipei, Taiwan |
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| Abstract: | 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 (BaP/DSS)‐induced colorectal tumorigenesis in ICR mice. We found that PMFs significantly prevented BaP/DSS‐induced colorectal tumor formation. BaP mutagenic metabolite and DNA adducts were found to be reduced in colonic tissue in the PMFs‐treated groups through the modulation of BaP metabolism. At the molecular level, the results of RNA‐sequencing indicated that PMFs ameliorated BaP/DSS‐induced abnormal molecular mechanism change including activated inflammation, downregulated anti‐oxidation targets, and induced metastasis genes. The autophagic defect caused by BaP/DSS‐induced tumorigenesis was improved by pretreatment with PMFs. We found BaP/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. BaP 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 BaP/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 BaP/DSS‐induced colorectal carcinogenesis. |
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| Keywords: | polycyclic aromatic hydrocarbons polymethoxyflavones colorectal cancer autophagic defect microbiota |
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