Early carcinogenic events in HNPCC adenomas:Differences with sporadic adenomas

Background Tumorigenesis in hereditary nonpolyposis colorectal cancer (HNPCC) differs from that in sporadic colorectal cancer during the early stage. We examined the expression of proliferation- and apoptosis-regulating proteins in relation to proliferation and apoptosis in HNPCC and sporadic adenomas. Methods Proliferation and apoptosis were quantified, and the expression of cyclin B1, D3 and E, p21, p27, bcl-2, bax, p53 and cox-2 was determined by immunohistochemistry in 100 patients (42 with HNPCC and 48 with sporadic adenomas). Results No differences between the two groups of patients in terms of proliferation and apoptosis were detected. Low-grade dysplastic HNPCC adenomas differed from sporadic ones by expressing bcl-2 more often (69 vs. 42%) and bax less often (50 vs. 73%). In comparison to sporadic adenomas, fewer high-grade dysplastic HNPCC expressed cyclin B1 and E (50 and 38% vs. 87 and 87%, respectively), p21 (6% vs. 53%) and bax (31% vs. 80%). In addition, HNPCC adenomas had a lower overexpression of p53 (5 vs. 19%). Conclusion The expression of cell cycle- and apoptosis-related proteins differs between HNPCC and sporadic adenomas from early through to advanced stages although proliferation and apoptosis are not different. These differences may contribute to the different clinical behavior of HNPCC and sporadic adenomas

Sulindac treatment in hereditary non-pollyposis colorectal cancer

Non-steroidal anti-inflammatory drugs, e.g. sulindac have been extensively studied for chemoprevention in familial adenomatous polyposis, but not in hereditary non-polyposis colorectal cancer (HNPCC). We evaluated these effects in HNPCC using surrogate end-points for cancer risk. In a randomised double-blind cross-over study, 22 subjects (9 female; age 30-66 years, mean 44), all ascertained or probable mutation carriers for HNPCC, were included. Sulindac 150 mg b.i.d. and placebo were given for 4 weeks each, with 4 weeks in between, with biopsies taken from ascending, transverse and sigmoid colon and rectum by colonoscopy after both periods. Proliferation was determined by Ki-67 staining and apoptosis by staining of cytokeratin 18 cleavage products. Expression of cyclins B1, D3 and E and p21, p27, bax, bcl2 and cox-2 was studied immunohistochemically. Proliferation was higher during sulindac treatment than drug placebo treatment in ascending and transverse colon, but not in sigmoid and rectum. Apoptosis was not affected. Besides an increase in cyclin D3, no differences were found in expression of regulating proteins in the proximal colon. Conclusion: Sulindac induces an increase in epithelial cell proliferation in the proximal colon of subjects with HNPCC. Since colorectal cancer predominantly arises in the proximal colon in HNPCC, these results cast doubts on the potential chemopreventive effects of sulindac in HNPCC. (C) 2007 Elsevier Ltd. All rights reserved

GATA6 expression in Barrett's metaplasia development and malignant progression

26 Background: Barrett’s metaplasia is characterized by the presence of a columnar metaplastic epithelium in the esophagus. Barrett’s metaplasia can show malignant progression towards esophageal adenocarcinoma by a metaplasia-dysplasia-carcinoma sequence. The underlying mechanisms of Barrett’s metaplasia development and malignant progression are poorly understood. The transcription factor GATA-6 is known to be involved in columnar differentiation and carcinogenesis. GATA6 gene amplification was recently linked with aggressiveness in esophageal adenocarcinoma. Here, we studied GATA6 protein expression in normal squamous, metaplastic, dysplastic and esophageal adenocarcinoma tissues in order to identify a possible role of GATA-6 in the development and malignant progression of Barrett’s metaplasia. Methods: Samples of squamous epithelium (N=37), Barrett’s non-intestinal metaplasia (N=16), Barrett’s intestinal metaplasia (N=29), high-grade dysplasia (N= 39), in situ esophageal adenocarcinoma (N=29) and an esophageal adenocarcinoma tissue microarray (N=95) were stained with a polyclonal antibody against GATA6. Staining intensity was categorized as absent, weak, normal or strong. Scoring was performed by two independent observers and validated by a pathologist. Results: GATA6 expression was absent in squamous epithelium but expressed in all samples of Barrett’s metaplasia, preferentially in the lower half of the crypt. Expansion of GATA6-positive cells throughout the crypt was observed in high-grade dysplasia. While all cases of in situ esophageal adenocarcinoma showed GATA6 expression we observed complete loss of GATA6 expression in 17% of esophageal adenocarcinoma samples. Conclusions: GATA6 is absent in squamous epithelium but its expression increases along the metaplasia-dysplasia carcinoma sequence. GATA6 expression remains predominantly present in esophageal adenocarcinoma, however, its expression is lost in a subset of samples. Analysis of the relation between GATA6 expression and clinicopathological characteristics in esophageal adenocarcinoma is pending. </jats:p

TRAIL induces apoptosis in human colorectal adenoma cell lines and human colorectal adenomas

Purpose: Recombinant human (rh) tumor necrosis factor - related apoptosis-inducing ligand (TRAIL) is a potential new anticancer drug which can induce apoptosis in colorectal cancer cell lines. The aim of this study was to investigate whether it is possible to induce apoptosis in human adenoma cell lines and human adenomas using rhTRAIL. Experimental Design: Two human adenoma cell lines were exposed to 0.1 mu g/mL of rhTRAIL for 5 hours. Apoptosis and caspase activation in cell lines were evaluated using immunocytochemistry, fluorimetric caspase assays, and Western blotting. Short-term explant cultures were established from freshly removed human adenomas (n = 38) and biopsies of normal colon epithelium (n = 15), and these were incubated for 5 hours in the presence or absence of 1 mu g/mL of rhTRAIL. Apoptosis was determined in paraffin-embedded tissue using morphologic criteria and cleaved caspase-3 staining. Results: In the adenoma cell lines, rhTRAIL induced up to 55% apoptosis. This coincided with caspase-8 and caspase-3 activation and could be inhibited by a pan-caspase inhibitor. rhTRAIL induced caspase-dependent apoptosis in adenomas with high-grade dysplasia (n = 21) compared with the paired untreated counterparts (apoptotic index, 34 +/- 5% versus 17 +/- 2%, mean +/- SE; P = 0.002), but not in adenomas with low-grade dysplasia (n 17) or in normal colon epithelium (n = 15). Conclusions: Colorectal adenoma cell lines and adenomas with high-grade dysplasia are sensitive to rhTRAIL-induced apoptosis, whereas normal colon epithelium is not. This suggests the potential application of rhTRAIL in the treatment of adenomas with high-grade dysplasia

Circulating miRNAs in patients with Barrett's esophagus, high-grade dysplasia and esophageal adenocarcinoma

Background: Diagnostic screening of premalignant esophageal lesions is hampered by the absence of biomarkers indicative of metaplastic and/or malignant transformation. The aim of this exploratory study was to investigate the potential use of miRNAs as biomarkers capable of identifying patients with (pre)malignant lesions: Barrett's esophagus (BE) metaplasia, high-grade dysplasia (HGD) or esophageal adenocarcinoma (EAC). Methods: A total of 69 patients were included in the study. Six serum samples from each of four study groups, i.e., patients with normal squamous epithelium (SE), BE, HGD and EAC, were profiled using the Nanostring miRNA analysis platform. Differential miRNA expression patterns then were validated in 69 patient samples using qRT-PCR. Results: miRNA expression profiling revealed seven miRNAs with a 2-fold change in expression level. Validation by qRT-PCR confirmed that serum miR-320e levels were significantly decreased in the BE group compared to the SE (P Conclusions: The results of this study suggest that decreased serum miRNA levels of miR-199a-3p and miR-320e could help to identify patients with BE and HGD

GATA6 expression in Barrett's oesophagus and oesophageal adenocarcinoma

BACKGROUND: Barrett's oesophagus can progress towards oesophageal adenocarcinoma through a metaplasia-dysplasia-carcinoma sequence, but the underlying mechanisms are poorly understood. The transcription factor GATA6 is known to be involved in columnar differentiation and proliferation, and GATA6 gene amplification was recently linked with poor survival in oesophageal adenocarcinoma. AIM: To study the expression of GATA6 during Barrett's oesophagus development and malignant transformation. To determine the prognostic value of GATA6 in oesophageal adenocarcinoma. METHODS: Two retrospective cohorts were derived from the pathological archive of the University Medical Center Groningen. The first cohort contained 130 tissue samples of normal squamous epithelium, metaplasia, dysplasia and oesophageal adenocarcinoma. The second cohort consisted of a tissue microarray containing tissue from 92 oesophageal adenocarcinoma patients. Immunohistochemistry was used to examine GATA6 protein expression and to correlate GATA6 expression in oesophageal adenocarcinoma with overall and disease-free survival. RESULTS: The percentage of GATA6-positive cells was low in squamous epithelium (10%) but increased progressively in Barrett's oesophagus (30%, P<0.001) and high-grade dysplasia (82%, P=0.005). GATA6 expression was not associated with overall or disease-free survival in oesophageal adenocarcinoma patients (P=0.599 and P=0.700 respectively). CONCLUSION: GATA6 expression is progressively increased during Barrett's oesophagus development and its malignant transformation. However, no prognostic value of GATA6 expression could be found in oesophageal adenocarcinoma