Brief Article
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World J Gastroenterol. Sep 28, 2013; 19(36): 6020-6025
Published online Sep 28, 2013. doi: 10.3748/wjg.v19.i36.6020
Disparities of conjugating protective enzyme activities in the colon of patients with adenomas and carcinomas
Harald P Hoensch, Hennie MJ Roelofs, Lutz Edler, Wilhelm Kirch, Wilbert HM Peters
Harald P Hoensch, Internal Medicine, Marien Hospital, D-64285 Darmstadt, Germany
Hennie MJ Roelofs, Wilbert HM Peters, Department of Gastroenterology, Radboud University Nijmegen Medical Center, 6525 GA Nijmegen, The Netherlands
Lutz Edler, Division of Biostatistics, German Cancer Research Center, D-69120 Heidelberg, Germany
Wilhelm Kirch, Department of Clinical Pharmacology, Technical University of Dresden, D-01307 Dresden, Germany
Author contributions: Hoensch HP is responsible for the study design, analysis and writing of the manuscript; Peters WHM and Roelofs HMJ performed the enzyme assays; Edler L analysed the data; Kirch W acts as guarantor for this article.
Supported by The Technical University of Dresden/Germany
Correspondence to: Harald P Hoensch, Professor, Internal Medicine, Marien Hospital, Martinspfad 72, Darmstadt D-64285, Germany. h.p.hoensch@t-online.de
Telephone: +49-6152-56768 Fax: +49-6152-56742
Received: April 9, 2013
Revised: June 26, 2013
Accepted: July 30, 2013
Published online: September 28, 2013
Processing time: 170 Days and 17.1 Hours
Abstract

AIM: To investigate the metabolic enzymatic capacity of the colon mucosa to detoxify noxious carcinogenic compounds.

METHODS: We investigated the activity of 2 conjugating enzymes-the microsomal uridine glucuronosyltransferase (UGT) and the cytosomal glutathione S-transferase (GST) in the uninvolved mucosa of the colon transversum and sigmoideum in patients with adenomatous polyps and colorectal cancer. Biopsies were taken from the mucosa during colonoscopies which were done for clinical (diagnostic) reasons. After storage, the biopsy material was homogenized and after differential centrifugation the enzyme assays were performed with 4-nitrophenol (UGT) and 1-chloro 2,4-dinitrobenzene (GST) as substrates.

RESULTS: About 48 patients were included of which 28 had adenomas and 20 had colorectal carcinomas confirmed by histopathology. Enzyme activities were expressed as nmol/mg per minute protein for the GST and as pmol/mg per minute protein for the UGT. Analysis of variance (F-test) indicated that both enzymes were more widely distributed in adenoma than in cancer patients. The means ± SD were smaller for cancer patients: GST for adenomas 268 ± 152 vs 241 ± 69 for carcinomas and UGT for adenomas 197 ± 200 vs 150 ± 86 for carcinomas.

CONCLUSION: Compared to patients with adenomatous colon polyps those with colorectal carcinoma exhibited a lower capacity of detoxifying enzyme metabolism and their activities clustered over a smaller range.

Keywords: Glutathione S-transferase; UDP-glucuronosyltransferase; Detoxification; Colon adenoma; Colon carcinoma

Core tip: Protective enzymes can conjugate carcinogenic chemicals. The functional capacity of these enzymes is diminished in patients with colorectal cancer and in some patients with colon adenomas.