A colorectal cell line with alterations in E-cadherin and epithelial biology may be an in vitro model of colitis

E-cadherin expression in colonic mucosa with and without fecal stream

The tissue content of E-cadherin changes in inflammatory bowel diseases; however, similar changes have not yet been evaluated in diversion colitis.

OBJECTIVE

The aim of this study was to evaluate the tissue expression of E-cadherin in the mucosa of the colon in both segments with and without a fecal stream.

METHODS

Sixty Wistar rats were subjected to deviation of fecal stream by proximal colostomy in left colon and a distal mucosal fistula. Animals were divided into three experimental groups that were sacrificed 6, 12, and 18 weeks after surgery. In each experimental group, five animals underwent laparotomy without intestinal deviation (control subgroup). Colitis was diagnosed based on the presence of three independent histological parameters: reduction of the crypt length, neutrophil infiltration of the mucosa and submucosa, and epithelial erosion or ulceration. The E-cadherin expression was evaluated by immunohistochemistry and the tissue levels by computerized morphometry. The Mann-Whitney and Kruskal-Wallis test were used to compare the groups adopting a significance level of 5% (p < .05).

RESULTS

Segments without fecal stream showed a reduction in E-cadherin content when compared with segments with fecal stream. In the segments with a fecal stream, E-cadherin was expressed at the apical surface of colon glands, while segments without fecal stream showed a decrease in the amount of apical E-cadherin. The content of E-cadherin was maintained over the entire time of the intestinal exclusion.

CONCLUSIONS

Diversion of the fecal stream decreases the expression of E-cadherin of the colon epithelium.

Cadherin switching dictates the biology of transitional cell carcinoma of the bladder: ex vivo and in vitro studies

Bladder cancer is the fifth most common malignancy in the UK. Clinically, the most important process in determining prognosis is the development of invasion, initially of the lamina propria and then beyond as these transitional cell carcinomas (TCCs) progress from stage pT1 to stages T2+. Cadherins and catenins are the main mediators of cell-cell interactions in epithelial tissues, and loss of membranous E-cadherin immunoreactivity is strongly correlated with high grade, advanced stage and poor prognosis in bladder cancer and other malignancies. However, the role of P-cadherin is yet to be fully elucidated in bladder TCC. The objectives of this study were to establish how the expression of cadherins and catenins determines clinical and in vitro behaviour in bladder TCC. Utilizing immunohistochemistry, immunofluorescence and western blotting, we demonstrated a significant reduction in the expression of E-cadherin and beta-catenin as grade and stage of bladder TCC progress, accompanied by a significant increase in P-cadherin expression (all p < 0.05, Pearson's chi2 test). Increased P-cadherin expression was also associated with a significantly worse bladder cancer-specific survival (log rank p = 0.008), with Cox regression showing P-cadherin to be an independent prognostic factor. Utilizing a variety of tissue culture models in a range of functional studies, we demonstrated that P-cadherin mediates defective cell-cell adhesion and enhances anchorage-independent growth. The results provide evidence that increased P-cadherin expression promotes a more malignant and invasive phenotype of bladder cancer, and appears to have a novel role late in the disease.

Met receptor signaling: a key effector in esophageal adenocarcinoma

PURPOSE

The incidence of esophageal adenocarcinoma is rising, and survival rates remain poor. The hepatocyte growth factor (HGF) receptor Met has been detected in esophageal cancer. The perturbation of cadherin/catenin complexes has also been shown. We sought to investigate a link among Met expression, cadherin/catenin biology, and cell growth. We assessed the prognostic significance of Met expression in esophageal adenocarcinoma.

EXPERIMENTAL DESIGN

Met and HGF expression in esophageal tissues were assessed using immunohistochemistry and ELISA. Met-positive cell lines (OE33 and SEG1) and a Met-negative cell line (TE7) were incubated with HGF. Real-time reverse transcription-PCR and Western blotting were used to assess levels of E-cadherin expression. Nuclear TCF/beta-catenin signaling was assessed following reporter construct transfection. Agar colony formation was used to assess anchorage-independent growth. A panel of 72 resected esophageal adenocarcinomas were assessed for Met expression by immunohistochemistry and correlated to survival data.

RESULTS

An increased expression of Met was seen along the metaplasia- adenocarcinoma sequence. Met-positive cells showed reductions in E-cadherin mRNA (37% and 69%) and protein expression following stimulation with HGF (P < 0.01). OE33 and SEG-1 showed up to a 2-fold increase in the levels of beta-catenin nuclear signaling (P < 0.01). TE7 only responded when transfected to express Met; E-cadherin expression decreased by 64% (P < 0.01). HGF stimulation led to increased agar colony formation (P < 0.01). Patients with Met-positive tumors showed lower 6-month survival rates after surgical resection than those with Met-negative tumors (P < 0.05).

CONCLUSIONS

Met activation induces changes consistent with early invasion, such as down-regulation of E-cadherin, increased nuclear TCF/beta-catenin signaling, and anchorage-independent growth. This is supported by ex vivo data associating Met with reduced short-term survival. Inhibitors of Met may be effective treatment for esophageal adenocarcinoma.

Assessment of differential gene expression patterns in human colon cancers

OBJECTIVE

To use a novel genomic approach to determine differential gene expression patterns in colon cancers of different metastatic potential.

SUMMARY BACKGROUND DATA

Colorectal cancer is the third leading cause of cancer deaths in the United States; despite aggressive treatment strategies, the 5-year survival rate for metastatic cancer has not changed in 50 years. The analysis of changes in gene expression patterns associated with metastasis may provide new treatment strategies.

METHODS

Human colon cancer cells KM12C (derived from a Dukes B colon cancer), KML4A (a metastatic variant derived from KM12C), and KM20 (derived from a Dukes D colon cancer) were extracted for RNA. In addition, RNA was extracted from normal colon, primary cancer, and liver metastasis in a patient with metastatic colon cancer. Gene expression patterns for approximately 1,200 human genes were analyzed and compared by cDNA array techniques.

RESULTS

Of the roughly 1,200 genes assessed in the KM cell lines, 9 genes were noted to have a more than threefold change in expression (either increased or decreased) in the more metastatic KML4A and KM20 cells compared with KM12C. Assessment of tissues from a patient with metastatic colon cancer demonstrated a more than threefold change in the expression of 14 genes in the primary cancer and liver metastasis compared with normal mucosa.

CONCLUSIONS

Using cDNA expression array technology, the authors identified genes with expression levels that are altered with metastasis. The ability to analyze and compare the expression patterns of multiple genes simultaneously provides a powerful technique to identify potential molecular targets for novel therapeutic strategies.