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Objective: Colorectal cancer remains the fourth most common cause of cancer-related mortality worldwide. Here we investigate the role of nuclear factor-κB (NF-κB) co-factor B-cell CLL/lymphoma 3 (BCL-3) in promoting colorectal tumour cell survival., Design: Immunohistochemistry was carried out on 47 tumour samples and normal tissue from resection margins. The role of BCL-3/NF-κB complexes on cell growth was studied in vivo and in vitro using an siRNA approach and exogenous BCL-3 expression in colorectal adenoma and carcinoma cells. The question whether BCL-3 activated the AKT/protein kinase B (PKB) pathway in colorectal tumour cells was addressed by western blotting and confocal microscopy, and the ability of 5-aminosalicylic acid (5-ASA) to suppress BCL-3 expression was also investigated., Results: We report increased BCL-3 expression in human colorectal cancers and demonstrate that BCL-3 expression promotes tumour cell survival in vitro and tumour growth in mouse xenografts in vivo, dependent on interaction with NF-κB p50 or p52 homodimers. We show that BCL-3 promotes cell survival under conditions relevant to the tumour microenvironment, protecting both colorectal adenoma and carcinoma cells from apoptosis via activation of the AKT survival pathway: AKT activation is mediated via both PI3K and mammalian target of rapamycin (mTOR) pathways, leading to phosphorylation of downstream targets GSK-3β and FoxO1/3a. Treatment with 5-ASA suppressed BCL-3 expression in colorectal cancer cells., Conclusions: Our study helps to unravel the mechanism by which BCL-3 is linked to poor prognosis in colorectal cancer; we suggest that targeting BCL-3 activity represents an exciting therapeutic opportunity potentially increasing the sensitivity of tumour cells to conventional therapy., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/)

Objective: Enteric glia activation has been reported to amplify intestinal inflammation via the enteroglial-specific S100B protein. This neurotrophin promotes macrophage recruitment in the mucosa, amplify colonic inflammation and interacts with toll-like receptors (TLR). Molecules inhibiting S100B-driven enteric activation might mitigate the course of ulcerative colitis (UC). This study aims to investigate the effects of palmitoylethanolammide (PEA), a drug able to counteract astroglial activation in the central nervous system, on intestinal inflammation, in humans and mice., Design: Mouse models of dextran sodium sulphate (DSS)-induced colitis, colonic biopsies deriving from UC patients and primary cultures of mouse and human enteric glial cells (EGC), have been used to assess the effects of PEA, alone or in the presence of specific PPARα or PPARγ antagonists, on: macroscopic signs of UC (DAI score, colon length, spleen weight, macrophages/neutrophils infiltration); the expression and release of proinflammatory markers typical of UC; TLR pathway in EGCs., Results: PEA treatment improves all macroscopic signs of UC and decreases the expression and release of all the proinflammatory markers tested. PEA anti-inflammatory effects are mediated by the selective targeting of the S100B/TLR4 axis on ECG, causing a downstream inhibition of nuclear factor kappa B (NF-kB)-dependent inflammation. Antagonists at PPARα, but not PPARγ, abolished PEA effects, in mice and in humans., Conclusions: Because of its lack of toxicity, its ability in reducing inflammation and its selective PPARα action, PEA might be an innovative molecule to broaden pharmacological strategies against UC., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)

Background and Aims: Folate has been implicated as a potential aetiological factor for colorectal cancer. Previous research has not adequately exploited concentrations of folate in normal colonic mucosal biopsies to examine the issue., Methods: Logistic regression models were used to estimate ORs and 95% CIs of adenoma according to the tissue concentration of folate using asymptomatic average-risk women (40-70 years) in a colorectal cancer screening study. Of the 1593 eligible women who were offered enrolment, 1483 (93%) participated. Colonoscopy was complete to the caecum in 98.7% (1463/1483) of the subjects, and normal colonic tissue biopsies were obtained from 813 (56%) of these, of whom 170 had at least one adenoma., Results: A marginal reduction in risk for proximal adenomas (OR 0.56, 95% CI 0.29 to 1.09) but not distal adenomas (OR 1.01, 95% CI 0.43 to 2.37) was observed among women in the highest quintile of tissue folate concentration. A significant reduction in risk for advanced adenoma was observed for women in the highest quintile of tissue folate concentration (OR 0.24, 95% CI 0.06 to 0.93). Defining the outcome as proximal adenomatous and/or hyperplastic polyps, statistically significant inverse associations with tissue concentrations of folate were also observed (OR 0.54, 95% CI 0.31 to 0.95 for quintile 5 vs quintile 1)., Conclusions: These findings are consistent with the hypothesis that folate status of colonic mucosa is an exposure that is aetiologically important in determining the risk of particular molecular subtypes of colorectal cancer.

Background and Aims: Monocyte chemoattractant protein 1 (MCP-1) is increased transmurally in inflammatory bowel disease (IBD). Although MCP-1 is considered to play an important role in fibrotic disease in other organs, the role of MCP-1 in gut fibrosis is unknown. We investigated the fibrotic potential of MCP-1 in the gut by overexpressing this chemokine in the mouse colorectal wall., Methods: Intramural gene transfer by direct injection of adenovector into the mouse rectal wall was established. C57BL/6 and Rag2(-/-) (B and T cell deficient) mice received 2.5 x 10(9) plaque forming units of an adenovector encoding murine MCP-1 (AdMCP-1) or control virus (AdDL70) via intramural injection. Mice were killed at various time points and tissues were obtained for histopathological and biochemical analysis., Results: AdMCP-1 significantly increased collagen production in the colorectum and this was associated with significant elevation of transforming growth factor beta (TGF-beta) and tissue inhibitor of metalloproteinase (TIMP-1) protein. Transmural collagen deposition was observed after AdMCP-1 administration, and was accompanied by CD3+ T cells, F4/80+ macrophages, and vimentin+ cell infiltrates. Collagen was differentially distributed, with type I deposited in the muscularis mucosa and muscularis propria and type III in the submucosa and myenteric plexus. AdMCP-1 failed to induce collagen overproduction in immunodeficient Rag2(-/-) mice., Conclusion: These findings suggest that MCP-1 can induce fibrosis in the gut and that this process involves interaction between T cells and vimentin positive fibroblasts/myofibroblasts, as well as the subsequent upregulation of TGF-beta and TIMP-1 production. This model provides a basis for considering MCP-1 in the pathogenesis of strictures in IBD.

The colorectal biopsy specimens from 30 patients with chronic watery diarrhoea but normal endoscopic and radiographic findings were studied by light microscopy, morphometry, immunohistochemistry, and two patients with electron microscopy. The histological changes in the colorectum were originally diagnosed in six patients as lymphocytic colitis and in 24 patients as collagenous colitis. The analysis of the specimens for this study could delineate three distinct groups of microscopic colitis: lymphocytic colitis (six patients), collagenous colitis without lymphocytic attack on the surface epithelium (seven patients), and a mixed form presenting with both thickening of the collagen plate and increased number of intraepithelial lymphocytes (17 patients). No transformation was seen from one type to another during follow up of six patients for four to seven years. Increased numbers of active pericryptal myofibroblasts were found with the electron microscope in one patient with mixed microscopic colitis showing also myofibroblasts entrapped within the collagen layer. Hitherto undescribed flat mucosa of the ileum was found in one patient with lymphocytic colitis and both flat mucosa and thickening of the collagen plate in the ileum were seen in one patient with the mixed form of the disease. In another patient with mixed microscopic colitis, normalisation of the colorectal morphology occurred after temporary loop ileostomy, followed by the reappearance of both diarrhoea, inflammation, and thickening of the collagen plate after the ileostomy was reversed. No association was found between non-steroid anti-inflammatory drug (NSAID) consumption and collagenous or mixed microscopic colitis. The primary cause of microscopic colitis is probably an immunological reaction to luminal antigen/s, perhaps of ileal origin. The engagement of the pericryptal myofibroblasts in the disease process might result in the development of the various forms of microscopic colitis. An inverse relation between intraepithelial lymphocyte count and collagen thickness may indicate that microscopic colitis is a spectral disease.

Immunohistochemistry of the S phase related proliferating cell nuclear antigen (PCNA) was studied as an alternative to ex-vivo bromodeoxyuridine (BrdU) immunohistochemistry for assessment of human colonic cell proliferation. From 16 subjects without colonic disease biopsy specimens were collected from five different sites along the colorectum and processed for BrdU and PCNA immunohistochemistry. The mean proliferation index of PCNA was significantly higher at 133% of the value obtained with BrdU. There was, however, a good correlation between the results from both techniques (r = 0.6275; p < 0.05). Decrease in proliferation index along the colorectum was seen with both staining methods but was clearer with PCNA immunohistochemistry (caecum/ascending colon v rectum: 12.0 v 7.2; p < 0.004). The total number of crypt cells also decreased from proximal to distal (134 to 128; p < 0.06) but at no site correlated significantly with the proliferation index. It is concluded that in clinical cell kinetic studies staining for PCNA may serve as an attractive alternative to the BrdU incorporation assay.

To study changes in rectal mucosa that might be attributable to the effects of gluten, rectal biopsy specimens from untreated and treated gluten sensitised subjects were analysed morphometrically and by immunohistochemical techniques and were compared with a series of disease control mucosae. Although morphometry showed increased populations of plasma cells, lymphocytes, and mast cells in the mucosae of untreated patients, which were reduced (except for mast cells) by dietary gluten restriction, immunohistochemical techniques were far more sensitive in defining these changes. There were highly significant increases in CD3+ and gamma delta+ lymphocytes within both the lamina propria and the epithelium while neutrophils (CD15+ cells) were not at all prominent. Activated (CD25+) lymphocytes expressing interleukin (IL)-2 receptors were increased in lamina propria, usually subjacent to basal lamina, although a few IL-2R+ intraepithelial lymphocytes were found: other IL-2R+ cells were deemed to be macrophages (CD68+). These results clearly indicate that in untreated, gluten sensitised subjects the rectal mucosa shows a lymphoplasmacytoid reaction that is responsive to gluten restriction. The absence of neutrophilia suggests that this lesion is not a conventional inflammatory type proctitis, but rather one presumed to be induced by gluten antigen(s) present in the faecal stream--that is, a cell mediated form of response.

Previous reports of a selective mucin subclass defect in ulcerative colitis have been reassessed using high performance chromatography (Superose 6 and Mono Q) for mucin purification and fractionation coupled with analysis of the fractions obtained using a combination of enzyme linked lectin and mucin antibody assays. Mucin samples purified from snap frozen rectal biopsy specimens obtained from patients with ulcerative colitis (n = 12), Crohn's disease (n = 5), and non-inflammatory bowel disease control subjects (n = 9) were subject to ion exchange chromatography using a continuous 0-0.35 mol/l NaCl salt gradient with a final 2.5 mol/l NaCl step. In all samples the major proportion (mean (SD) 86.7 (8.9)%) of the mucin detectable by wheat germ agglutinin binding eluted between 0.15 and 0.35 mol/l NaCl with no significant difference in elution profile between ulcerative colitis and control subjects. Significant elution of glycoprotein at less than 0.15 mol/l NaCl did occur, however, when a lower molecular weight mucin containing fraction which contained concanavalin A positive (glucose or mannose containing) material was analysed similarly. Similar ion exchange profiles were obtained when (3H)N-acetylglucosamine labelled mucins were studied after tissue culture of rectal biopsy specimens. No significant alteration in the ion exchange profile of purified mucins in ulcerative colitis has been shown in these studies. It is possible that the previously reported relative depletion of mucin subclass IV (eluting with 0.20 mol/l NaCl) may simply have reflected mucin depletion.