Purpose: Walnuts (Juglans regia) are known to have anti-cancer and immunomodulatory effects. However, little information is available on the effects of walnut phenolic extract (WPE) on intestinal inflammation and colitis-associated colon cancer. Methods: COLO205 cells were pretreated with WPE and then stimulated with tumor necrosis factor (TNF)-α. In the acute colitis model, wild type mice (C57BL/6) were administered 4% dextran sulfate sodium (DSS) for 5 days. In the chronic colitis model, interleukin (IL)-10−/− mice were administered with either the vehicle or WPE (20 mg/kg) by oral gavage daily for 2 weeks. In an inflammation-associated tumor model, wild type mice were administered a single intraperitoneal injection of azoxymethane followed by three cycles of 2% DSS for 5 days and 2 weeks of free water consumption. Results: WPE significantly inhibited IL-8 and IL-1α expression in COLO205 cells. WPE attenuated both the TNF-α-induced IκB phosphorylation/degradation and NF-κB DNA binding activity. The administration of oral WPE significantly reduced the severity of colitis in both acute and chronic colitis models, including the IL-10−/− mice. In immunohistochemical staining, WPE attenuated NF-κB signaling in the colons of both colitis models. Finally, WPE also significantly reduced tumor development in a murine model of colitis-associated colon cancer (CAC). Conclusions: WPE ameliorates acute and chronic colitis and CAC in mice, suggesting that WPE may have potentials for the treatment of inflammatory bowel disease.
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Fig. 6 WPE attenuates tumor growth by inhibiting IKK activity and β-catenin signaling independent of inducing apoptosis in a CAC model. a Immunohistochemistry for phospho-IKK-α/β and representative colon samples of colonic epithelium in a murine model of CAC, treated with or without WPE. AOM/DSS exposure resulted in a significant increase in immunoreactivity for phospho-IKK-α/β staining. However, administration of WPE (20 mg/kg/day) significantly reduced the degree of phospho-IKK-α/β immunoreactivity in Acknowledgements This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education [Grant Number. NRF-2014R1A1A2057695(S-JK)], [2016-R1D1A1B03931961(S-JK)], by a multidisciplinary research grant-in-aid from the Seoul Metropolitan Government Seoul National University (SMG-SNU) Boramae Medical Center (02-2015-01) and by a Grant from California Walnut Commission.
© 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
- Colon cancer
- Inflammatory bowel disease
- Nuclear factor kappaB