Neutrophil Extracellular Trap Production in Patients with Colorectal Cancer In Vitro.

PURPOSE: Neutrophil Extracellular Traps (NETs) are extracellular neutrophil derived DNA webs which have been implicated in cancer progression and in the development of metastases. NETs production in patients with colorectal cancer was investigated to elucidate their role and prognostic significance. METHODS: Systemic neutrophils were isolated from consecutive patients with colorectal cancer and from age-matched healthy volunteers. Neutrophils were stimulated to produce NETs which were quantified by a measure of the fluorescence of the extracellular DNA. The impact of cancer location, tumour stage, and patient outcomes (complications, length of stay, and mortality) on NET production was investigated. RESULTS: Quantification of NET formation was performed in patients with colorectal cancer (n = 45) and in well-matched healthy individuals (n = 20). Significant increases in NETs production in response to no stimulant (9,735 AFU versus 11347 AFU, p = 0.0209), IL-8 (8,644 AFU versus 11,915 AFU, p = 0.0032), and LPS (10,576 AFU versus 12,473 AFU, p = 0.0428) were identified in patients with colorectal cancer. A significant increase in NETs production in response to fMLP was detected in patients who developed significant postoperative complications (11,760 AFU versus 18,340 AFU, p = 0.0242) and who had a prolonged hospital recovery (9,008 AFU versus 12,530 AFU, p = 0.0476). An increase in NETs production was also observed in patients who died, but this did not reach statistical significance. Cancer location and tumour stage did not appear to affect preoperative NETs production. CONCLUSIONS: Patients with colorectal cancer have significantly increased NETs production in vitro when compared to healthy volunteers, possibly implicating them in cancer development. Adverse patient outcomes were associated with increased preoperative NETs production, which highlights them as potential therapeutic targets.

Necrotizing fasciitis of chest wall complicating empyema thoracis.

Necrotizing fasciitis affecting the chest wall is a rare condition and carries high mortality. It spreads rapidly, requiring early diagnosis and immediate extensive surgical debridement. The case of a 32 year old man afflicted with this uncommon condition following tube thoracostomy for empyema thoracis is described and literature reviewed.

Glutathione S-transferase GSTT1 genotypes and susceptibility to cancer: studies of interactions with GSTM1 in lung, oral, gastric and colorectal cancers.

Allelism in glutathione S-transferase GSTM1 and GSTT1 has been suggested as a risk factor in various cancers. Accordingly, we describe a group of case-control studies carried out to identify associations between GSTT1 genotypes and susceptibility to lung, oral, gastric and colorectal cancers. The frequencies of the putatively high risk GSTT1 null genotype were not increased in the lung, oral or gastric cancer cases compared with controls but the frequency of this genotype was significantly increased (P = 0.0011, odds ratio = 1.88) in the colorectal cancer cases. No significant interactions between the GSTT1 and GSTM1 null genotypes types were identified in the cancer groups studied. Indeed, no significant associations between GSTM1 genotypes and susceptibility were identified though further evidence was obtained that the protective effect of GSTM1*A and GSTM1*B is not equal. The data complement studies showing that GSTT1 null is associated with an increased susceptibility to total ulcerative colitis and suggests that this enzyme is important in the detoxification of unidentified xenobiotics in the large intestine.

Polyadenylation polymorphism in the acetyltransferase 1 gene (NAT1) increases risk of colorectal cancer.

Exposure to carcinogens present in the diet, cigarette smoke, or the environment may be associated with increased risk of colorectal cancer. Aromatic amines (aryl- and heterocyclic) are a class of carcinogens that are important in these exposures. These compounds can be N- or O-acetylated by the NAT1 or NAT2 enzymes, resulting in activation or in some cases detoxification. Recent studies have shown that both NAT2 and NAT1 genes exhibit variation in human populations and that rapid acetylation by the NAT2 enzyme may be a risk factor for colorectal cancer. In this study we have analyzed for genetic polymorphism in both NAT1 and NAT2 in a group of 202 colorectal cancer patients and 112 control subjects from Staffordshire, England. We find significantly increased risk (odds ratio, 1.9; 95% confidence interval, 1.2-3.2; P = 0.009) associated with the NAT1*10 allele of NAT1, an allele that contains a variant polyadenylation signal. Individuals with higher stage tumors (Duke's C) were more likely to inherit this variant allele (odds ratio, 2.5; 95% confidence interval, 1.3-4.7; P = 0.005). In contrast, rapid acetylation genotypes of NAT2 were not a significant risk factor in this English population. However, we found that the risk associated with the NAT1 variant allele (NAT1*10) was most apparent among NAT2 rapid acetylators (odds ratio, 2.8; 95% confidence interval, 1.4-5.7; P = 0.003), suggesting a possible gene-gene interaction between NAT1 and NAT2 (test for interaction; P = 0.12). This is the first study to test for cancer risk associated with the NAT1 gene, and these positive findings suggest that NAT1 alleles may be important genetic determinents of colorectal cancer risk.

Dietary omega-3 fats reduce proliferation and tumor yields at colorectal anastomosis in rats.

BACKGROUND & AIMS: Colorectal anastomoses show increased mucosal crypt cell proliferation rates (CCPRs) and often form the site for tumor recurrence after resection of colorectal cancer. The aim of this study was to assess the effects of a 20% omega-3 fat diet on CCPRs and anastomotic tumor formation compared with an isocaloric 20% saturated fat diet in experimental colorectal cancer. METHODS: One hundred sixty male Wistar rats were administered azoxymethane or saline for 6 weeks, after which a colonic anastomosis or sham operation was performed. CCPR, mucosal fatty acids, and tumor yield were analyzed at the anastomosis and proximal and distal colon sites at 15 and 23 weeks. RESULTS: Diet, carcinogen treatment, and surgery all had significant effects on CCPR with omega-3 fats producing the lowest CCPR at all sites. There were fewer tumors (P < 0.02), including a marked reduction of anastomotic tumors in omega-3 fat-fed animals that was associated with a significant reduction of arachidonic acid in mucosal and tumor lipids. CONCLUSIONS: Dietary omega-3 fat significantly reduced colonic CCPR and tumor yield, including at the site of anastomosis. Dietary omega-3 fats may be of value to patients after colorectal resection and anastomosis for cancer and warrant further testing.

Activities of phospholipase A2 and diacylglycerol lipase are increased in human colorectal cancer.

Experimental, clinical and epidemiological studies have implicated arachidonic acid and its metabolites as important mediators in colorectal carcinogenesis. Although arachidonic acid levels are increased in tumour membrane lipids, its availability for metabolic processes is not known. The activities of phospholipase A2 (PLA2) and diacylglycerol lipase therefore were assessed in tumour and normal mucosal specimens from 20 patients with colorectal cancer using 14C-radiolabelled substrates. The median (interquartile range) PLA2 activity was increased in tumour tissue (10.5 (6.0, 18.5) pmol arachidonic acid mg-1 h-1) compared with that in normal mucosa (5.6 (2.5, 8.5) pmol arachidonic acid mg-1 h-1) (P < 0.001, Wilcoxon signed rank test). Activity of diacylglycerol lipase was also greater in tumoral tissue (47.4 (21.6, 82.1) pmol arachidonic acid mg-1 h-1) than in mucosa (19.1 (9.4, 42.9) pmol arachidonic acid mg-1 h-1) (P < 0.005). There was no correlation between either PLA2 or diacylglycerol lipase activity and myeloperoxidase activity, suggesting that these increases were not directly attributable to tumour inflammatory cell infiltrate. Augmentation of arachidonic acid release in colorectal tumours may have implications for therapy.

Lipid peroxidation and prostaglandins in colorectal cancer.

Dietary fat, arachidonic acid metabolism and lipid peroxidation have all been implicated in colorectal carcinogenesis. Fatty acids, prostaglandins (PGE2, PGF2 alpha) and malondialdehyde (MDA), the stable end-product of lipid peroxidation of polyunsaturated fatty acids (PUFAs), were studied in paired tumour and normal mucosa of 20 patients with colorectal cancer. Levels of arachidonic acid and total PUFAs were increased in the phospholipid fraction of tumours (P < 0.05). Levels of PGE2 and MDA were also higher in tumours (P < 0.001) and there was a significant correlation between MDA and PGE2 concentrations (rs = 0.69, P < 0.01). In contrast to previously reported in vitro studies, this work suggests that lipid peroxidation may be enhanced in human colorectal tumours. As PGE2 and MDA have been shown to be involved in carcinogenesis, these may be considered potential therapeutic targets for preventing or treating colorectal carcinoma.

Enteric alpha-1-antitrypsin loss and comparison with Okokit II and Haemoccult for the detection of colorectal cancer.

Faecal samples from patients with symptomatic colorectal cancer (n = 19) and from control subjects (n = 54) were analysed for alpha-1-antitrypsin (A1AT) and compared with Haemoccult and Okokit II. A1AT was also measured in paired samples of normal colonic mucosa and cancer tissue (n = 16) and in media from four human colorectal cell lines (COLO 320 DM, SW620, HT29, LS 174T). Faecal A1AT concentrations were greater than controls (P < 0.0001) and detected 12 (63%) patients with cancer compared to 10 (53%) by Okokit II and 7 (37%) by Haemoccult (P > 0.05). A1AT concentrations from colonic mucosa (median, range: 0.46, 0.17-0.79 mg/g wet wt) were greater (P = 0.01) than cancer tissue (0.29, 0.13-0.74 mg/g wt wt). Adjusting for albumin, A1AT concentrations from mucosa (12.0, 3.8-32.2 mg/g albumin) remained greater (P = 0.003) than for cancer tissue (5.9, 2.4-21.4 mg/g albumin). A1AT was not detected in any of the cell-line media. The most likely mechanisms for increased faecal A1AT concentrations, apart from increased blood loss, are increased cell turnover or leakage from epithelial tight junctions. The use of faecal A1AT measurement for the detection of colorectal cancer deserves further assessment.

Oestrogen and progesterone receptors in colorectal cancer and human colonic cancer cell lines.

Receptors for oestrogen (ER) and progesterone (PR) were assayed in tissue from 17 patients with colorectal cancer and five colonic cancer cell lines using enzyme immunoassays. ERs and PRs were detected in 15 and 17 cancers respectively, although the levels detected were low: median (range) ER 1.3 (0-11.3) and PR 3.9 (0.3-10.2) fmol per mg protein. These values were not significantly different from median (range) levels of ER (1.1 (0.6-3.0) fmol/mg) and PR (1.9 (0.5-3.2) fmol/mg) detected in normal mucosa. There were significant positive correlations between the levels of ER and PR for cancer tissue (tau = 0.56, P < 0.005; r(log transform) = 0.68, P < 0.003; n = 17) but not for mucosa, and between levels of ER in cancer tissue and mucosa (tau = 0.55, P < 0.05; r(log transform) = 0.70, P < 0.025; n = 10) but not between the corresponding PR values. In maintenance media, which contained phenol red and unstripped fetal calf serum, the median (range) concentration of ER was 1.9 (1.2-10.4) fmol/mg and that for PR 24.3 (9.1-63.2) fmol/mg in the five cell lines studied (HT-29, LS174T, SW620, LoVo, COLO 320DM). The addition of oestradiol (10 nmol/l) to phenol red-free medium containing 5 per cent dextran-coated charcoal-treated fetal calf serum had little effect on the concentration of ERs or PRs in SW620, LoVo and COLO 320DM cells after 7 days' culture. It is concluded that ERs and PRs are expressed in malignant and normal colonic mucosa. ERs appear to be a feature of the colonic mucosa rather than the malignant process, but in carcinoma may regulate synthesis of PRs, suggesting a degree of oestrogen responsiveness.

Faecal unconjugated bile acids in patients with colorectal cancer or polyps.

The unconjugated faecal bile acid profiles of 14 patients with colorectal cancer, nine patients with polyps and 10 controls were compared using gas liquid chromatography, controlling for such confounding variables as cholecystectomy, gall stones and hepatic function. Patients with adenomatous polyps had a higher concentration of faecal bile acids (5.23 mumol/g, 2.16-13.67 (median, range) v 1.96, 0.91-6.97; p = 0.016) lithocholic acid (2.41, 0.88-3.22 v 1.07, 0.38-2.03; p = 0.013) and total secondary bile acids (5.23, 2.16-13.4 v 1.96, 0.73-6.63; p = 0.02) compared with control subjects. Patients with colorectal cancer had an increased (p = 0.029) proportion of secondary faecal bile acids (mol%) compared with controls (100, 96.5-100 v 95.19, 81.73-100) and the ratios of the primary bile acids, cholic and chenodeoxycholic acid, to their respective derivatives (secondary bile acids) were significantly lower in cancer patients compared with control and patients with polyps (p = 0.034 to 0.004). This study lends further support to the theory that bile acids may play a role in the development of polyps and colorectal cancer.

Reduction of mucosal crypt cell proliferation in patients with colorectal adenomatous polyps by dietary calcium supplementation.

The crypt cell production rate was measured in 14 patients with adenomatous colorectal polyps, 17 patients with colorectal cancer and 12 control subjects. The median (interquartile range) rate (cells per crypt per hour) was found to be significantly higher (P less than 0.001) in the polyp (2.45 (1.94-3.20)) and cancer (3.01 (2.35-3.68)) groups compared with controls (1.25 (0.70-1.85)). A double-blind cross-over study was performed in patients with adenomatous polyps consisting of 2 months' treatment, 2 weeks' washout, followed by 2 months' treatment with dietary calcium supplementation (1.25 g day-1) versus placebo. A significant reduction in the crypt cell production rate occurred with calcium treatment compared with the placebo (1.25 (0.6-2.25) versus 2.15 (1.58-3.08) cells per crypt per hour, P = 0.035). This study demonstrates a significant reduction in mucosal cell proliferation by dietary calcium supplementation in patients with adenomatous polyps. Such treatment may be worthy of further investigation in patients at high risk of developing colorectal polyps.