Miniprobe CLM showed a high negative predictive value for the diagnosis of endoscopically invisible neoplasia in Barrett's oesophagus; sensitivity, however, has still to be improved.

The human coxsackievirus and adenovirus receptor (CAR) represents the primary cellular site of adenovirus attachment during infection. An understanding of the mechanisms regulating its expression could contribute to improving efficacy and safety of adenovirus-based therapies. We characterized regulation of CAR expression in a 3D cell culture model of human breast cancer progression, which mimics aspects of the physiological tissue context in vitro. Phenotypically normal breast epithelial cells (S1) and their malignant derivative (T4-2 cells) were grown either on tissue culture plastic (2D) or 3D cultures in basement membrane matrix. S1 cells grown in 3D showed low levels of CAR, which was expressed mainly at cell-cell junctions. In contrast, T4-2 cells expressed high levels of CAR, which was mainly in the cytoplasm. When signaling through the epidermal growth factor receptor was inhibited in T4-2 cells, cells reverted to a normal phenotype, CAR protein expression was significantly reduced, and the protein relocalized to cell-cell junctions. Growth of S1 cells as 2D cultures or in 3D in collagen-I, a nonphysiological microenvironment for these cells, led to up-regulation of CAR to levels similar to those in T4-2 cells, independently of cellular growth rates. Thus, expression of CAR depends on the integrity and polarity of the 3D organization of epithelial cells. Disruption of this organization by changes in the microenvironment, including malignant transformation, leads to up-regulation of CAR, thus enhancing the cell's susceptibility to adenovirus infection.

pCLE can be regarded as non-inferior to endoscopic biopsy in excluding neoplasia of Barrett's esophagus mucosa. However, due to its low PPV and sensitivity, pCLE may currently not replace standard biopsy techniques for the diagnosis of Barrett's esophagus and associated neoplasia. Further technical development of pCLE and a better understanding of its role in relation to other imaging technologies are necessary.

Loss of the coxsackie and adenovirus receptor (CAR) has previously been observed in gastric cancer. The role of CAR in gastric cancer pathobiology, however, is unclear. We therefore analysed CAR in 196 R 0 -resected gastric adenocarcinomas and noncancerous gastric mucosa samples using immunohistochemistry and immunofluorescence. Coxsackie and adenovirus receptor was found at the surface and foveolar epithelium of all non-neoplastic gastric mucosa samples (n ¼ 175), whereas only 56% of gastric cancer specimens showed CAR positivity (Po0.0001). Loss of CAR correlated significantly with decreased differentiation, increased infiltrative depths, presence of distant metastases, and was also associated with reduced carcinoma-specific survival. To clarify whether CAR impacts the tumorbiologic properties of gastric cancer, we subsequently determined the role of CAR in proliferation, migration, and invasion of gastric cancer cell lines by application of specific CAR siRNA or ectopic expression of a human full-length CAR cDNA. These experiments showed that RNAi-mediated CAR knock down resulted in increased proliferation, migration, and invasion of gastric cancer cell lines, whereas enforced ectopic CAR expression led to opposite effects. We conclude that the association of reduced presence of CAR in more severe disease states, together with our findings in gastric cancer cell lines, suggests that CAR functionally contributes to gastric cancer pathogenesis, showing features of a tumour suppressor.

Purpose: To establish xenograft mouse models of metastatic and nonmetastatic human prostate cancer and to apply these models to the search for aberrant glycosylation patterns associated with tumor progression in vivo and in patients.Experimental Design: Prostate cancer cells (LNCaP, PC-3, LuCaP 23.1, and DU-145) were xenografted subcutaneously into immunodeficient pfpÀ/À mice. Tumor growth and metastasis formation were quantified and as altered glycosylation patterns have been associated with metastasis formation in several other malignancies, prostate cancer cells were profiled by a quantitative real-time PCR (qRT-PCR) glycosylation array and compared with normal human prostate cells. The activity of upregulated glycosyltransferases was analyzed by their sugar residues end products using lectin histochemistry on primary tumors and metastases in the animal experiments and on 2,085 clinical samples.Results: PC-3 cells produced the largest number of spontaneous lung metastases, followed by LNCaP and LuCaP 23.1, whereas DU-145 was nonmetastatic. qRT-PCR revealed an upregulation of b1,6-Nacetylglucosaminyltransferase-5b (Mgat5b) in all prostate cancer cell lines. Mgat5b products [b(1,6)-branched oligosaccharides] were predominantly detectable in metastatic xenografts as shown by increased binding of Phaseolus vulgaris leukoagglutinin (PHA-L). The percentage of prostate cancer patients who were PHA-L positive was 86.5. PHA-L intensity correlated with serum prostate-specific antigen and a cytoplasmic staining negatively affected disease-free survival.Conclusion: We show a novel xenograft mouse model for human prostate cancer respecting the complete metastatic cascade. Specific glycosylation patterns reveal Mgat5b products as relevant markers of both metastatic competence in mice and disease-free survival in patients. This is the first description of Mgat5b in prostate cancer indicating a significant biologic importance of b(1,6)-branched oligosaccharides for prostate cancer progression.

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Expression of the Coxsackie and Adenovirus Receptor (CAR) is frequently reduced in carcinomas, resulting in decreased susceptibility of such tumors to infection with therapeutic adenoviruses. Because CAR participates physiologically in the formation of tight-junction protein complexes, we examined whether molecular mechanisms known to down-regulate cellcell adhesions cause loss of CAR expression. Transforming growth factor-B (TGF-B)-mediated epithelial-mesenchymal transition (EMT) is a phenomenon associated with tumor progression that is characterized by loss of epithelial-type cell-cell adhesion molecules (including E-cadherin and the tight junction protein ZO-1), gain of mesenchymal biochemical markers, such as fibronectin, and acquisition of a spindle cell phenotype. CAR expression is reduced in tumor cells that have undergone EMT in response to TGF-B. This downregulation results from repression of CAR gene transcription, whereas altered RNA stability and increased proteasomal protein degradation play no role. Loss of CAR expression in response to TGF-B is accompanied by reduced susceptibility to adenovirus infection. Indeed, treatment of carcinoma cells with LY2109761, a specific pharmacologic inhibitor of TGF-B receptor types I and II kinases, resulted in increased CAR RNA and protein levels as well as improved infectability with adenovirus. This was observed in cells induced to undergo EMT by addition of exogenous TGF-B and in those that were transformed by endogenous autocrine/paracrine TGF-B. These findings show down-regulation of CAR in the context of EMT and suggest that combination of therapeutic adenoviruses and TGF-B receptor inhibitors could be an efficient anticancer strategy. (Cancer Res 2006; 66(3): 1648-57)

Background:The Coxsackie- and Adenovirus Receptor (CAR) has been assigned two crucial attributes in carcinomas: (a) involvement in the regulation of growth and dissemination and (b) binding for potentially therapeutic adenoviruses. However, data on CAR expression in cancer types are conflicting and several entities have not been analysed to date.Methods:The expression of CAR was assessed by immunohistochemical staining of tissue microarrays (TMA) containing 3714 specimens derived from 100 malignancies and from 273 normal control tissues.Results:The expression of CAR was detected in all normal organs, except in the brain. Expression levels, however, displayed a broad range from being barely detectable (for example, in the thymus) to high abundance expression (for example, in the liver and gastric mucosa). In malignancies, a high degree of variability was notable also, ranging from significantly elevated CAR expression (for example, in early stages of malignant transformation and several tumours of the female reproductive system) to decreased CAR expression (for example, in colon and prostate cancer types).Conclusion:Our results provide a comprehensive insight into CAR expression in neoplasms and indicate that CAR may offer a valuable target for adenovirus-based therapy in a subset of carcinomas. Furthermore, these data suggest that CAR may contribute to carcinogenesis in an entity-dependent manner.