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Metallothionein crypt-restricted immunopositivity indices (MTCRII) correlate with aberrant crypt foci (ACF) in mouse colon.

ABSTRACT: Metallothionein (MT) crypt-restricted immunopositivity indices (MTCRII) are colonic crypt stem cell mutation markers that may be induced early and in abundance after mutagen treatment. Metallothionein is the endogenous reporter gene for MTCRII, but is not typically implicated in the classical pathway of colorectal tumorigenesis. Hence, the oncological relevance of MTCRII is unclear. This study tests the hypothesis that MTCRII induced by N-methyl-N-nitrosourea (MNU) and lambda carrageenan (lambdaCgN) associate with aberrant crypt foci (ACF) in mouse colon. Undegraded lambdaCgN and MNU were tested alone and in combination against MTCRII and ACF in Balb/c mice, at 20 weeks after the start of treatment. MTCRII were unaffected by lambdaCgN alone. Combined lambdaCgN/MNU treatments induced greater MTCRII (P < 0.01) as well as greater number (P < 0.001) and crypt multiplicity (P < 0.01) of ACF than MNU alone. MTCRII were approximately 10-fold more numerous than ACF, although linear correlations were observed between these parameters (r = 0.732; P < 0.01). MTCRII are induced by lambdaCgN/MNU interactions in sufficient numbers to provide statistical power from relatively small sample sizes and correlate with ACF formation. MTCRII could thus provide the basis for a novel medium-term murine bioassay relevant to early-stage colorectal tumorigenesis.

SUBMITTER: Donnelly ET

PROVIDER: S-EPMC2361830 | biostudies-other | 2005 Jun

REPOSITORIES: biostudies-other

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Project description:BackgroundAcanthus ilicifolius, a mangrove medicinal plant, is traditionally used to treat a variety of diseases. The aim of this research is to assess the chemoprotective outcomes of A. ilicifolius ethanolic extract against azoxymethane (AOM) induced colonic aberrant crypt foci (ACF) in rats.Methodology/principal findingsIn our study, rats were arranged in to five groups. Rats in the normal control group were given subcutaneous injections of normal saline once weekly for 2 weeks. The AOM control, reference and treatment groups were given subcutaneous injection of AOM, 15 mg/kg body weight, once weekly for 2 weeks each. The reference group was treated with 35 mg/kg 5-Fluorouracil via intraperitoneal injection once weekly for 8 weeks, and the treatment groups were administered by gavage with 250 and 500 mg/kg A. ilicifolius extract daily for 8 weeks. Both normal and AOM control groups received the vehicle; 10% Tween-20 only. Rats treated with 250 mg/kg and 500 mg/kg of A. ilicifolius extracts showed a decrease in the mean number of ACF by 65% and 53%, respectively. Those fed with A. ilicifolius showed significantly decreased multiplicity of ACF formations when compared with the results from the AOM control group. The 250 mg/kg A. ilicifolius treatment group showed significant decreases in lipid peroxidation MDA levels when compared with the AOM control group. In immunohistochemistry staining, the proliferating nuclear cell antigen (PCNA)-positive cells were significantly higher in the AOM control group than in the A. ilicifolius-treated groups. RT-PCR showed that A. ilicifolius caused a change in the regulation of apoptosis-related genes expression.Conclusion/significanceThe results of the current study show that AOM-treated rats receiving oral exposure to A. ilicifolius demonstrated a significant decrease in the number of ACF in the colon when compared to AOM-treated rats receiving vehicle only. A ilicifolius may be an effective herbal approach for the prevention of AOM-induced ACF in the rat colon.

Project description:Aberrant crypt foci (ACF) are the earliest morphologically identifiable lesion found within the human colon. Despite their relatively high frequency in the distal colon, few studies have examined the molecular characteristics of ACF within the proximal colon. In the following study, clinical participants (n = 184) were screened for ACF using high-definition chromoendoscopy with contrast dye-spray. Following pathologic confirmation, ACF biopsies were subjected to laser capture microdissection (LCM), and epithelial cells were evaluated for somatic mutations with a customized colorectal cancer mutation panel using DNA-mass spectrometry. Samples were further characterized for microsatellite instability (MSI). Logistic models were used to associate proximal ACF with synchronous (detected during the same procedure) neoplasia. Thirty-nine percent of participants had at least one histologically confirmed proximal ACF. Individuals with a proximal ACF were significantly more likely to present with a synchronous neoplasm (P = 0.001), and specifically, a proximal, tubular, or tubulovillous adenoma (multivariable OR = 2.69; 95% confidence interval, 1.12-6.47; P = 0.027). Proximal ACF were more likely to be dysplastic (52%) compared with distal ACF (13%; P < 0.0001). Somatic mutations to APC, BRAF, KRAS, NRAS, and ERBB2 were detected in 37% of proximal ACF. Hyperplastic ACF were more often MSI-high, but there were no differences in MSI status observed by colonic location. In summary, ACF are identified in the proximal colons of approximately 40% of individuals undergoing chromoendoscopy and more often in patients with synchronous proximal adenomas.Implications: This study provides the most complete set of data, to date, that ACF represent the earliest step in the adenoma-carcinoma sequence but remain below the detection limit of conventional endoscopy.Visual Overview: http//mcr.accrjournals.org/content/molcanres/16/3/486/F1.large.jpg Mol Cancer Res; 16(3); 486-95. ©2017 AACR.

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Metallothionein crypt-restricted immunopositivity indices (MTCRII) correlate with aberrant crypt foci (ACF) in mouse colon.

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