Microbial carcinogenic toxins and dietary anti-cancer protectants

Stone, T. W. and Darlington, L. G. (2017) Microbial carcinogenic toxins and dietary anti-cancer protectants. Cellular and Molecular Life Sciences, 74(14), pp. 2627-2643. (doi: 10.1007/s00018-017-2487-z) (PMID:28238104) (PMCID:PMC5487888)

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Several toxins are known which account for the ability of some bacteria to initiate or promote carcinogenesis. These ideas are summarised and evidence is discussed for more specific mechanisms involving chymotrypsin and the bacterial chymotryptic enzyme subtilisin. Subtilisin and Bacillus subtilis are present in the gut and environment and both are used commercially in agriculture, livestock rearing and meat processing. The enzymes deplete cells of tumour suppressors such as deleted in colorectal cancer (DCC) and neogenin, so their potential presence in the food chain might represent an important link between diet and cancer. Over-eating increases secretion of chymotrypsin which is absorbed from the gut and could contribute to several forms of cancer linked to obesity. Inhibition of these serine proteases by Bowman–Birk inhibitors in fruit and vegetables could account for some of the protective effects of a plant-rich diet. These interactions represent previously unknown non-genetic mechanisms for the modification of tumour suppressor proteins and provide a plausible explanation contributing to both the pro-oncogenic effects of meat products and the protective activity of a plant-rich diet. The data suggest that changes to farming husbandry and food processing methods to remove these sources of extrinsic proteases might significantly reduce the incidence of several cancers.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Stone, Professor Trevor
Authors: Stone, T. W., and Darlington, L. G.
College/School:College of Medical Veterinary and Life Sciences > School of Psychology & Neuroscience
Journal Name:Cellular and Molecular Life Sciences
ISSN (Online):1420-9071
Published Online:25 February 2017
Copyright Holders:Copyright © 2017 The Authors
First Published:First published in Cellular and Molecular Life Sciences 74(14): 2627-2643
Publisher Policy:Reproduced under a Creative Commons license

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