In epithelial tissue, cell-matrix and cell-cell adhesive interactions have important roles in the normal organization and stabilization of the cell layer. The malignant conversion of epithelial cells involves alterations in the expression and function of these adhesion systems that enable a switch to a migratory phenotype in tumor invasion and metastasis. Fascin is an actin-crosslinking protein that is found in the core actin bundles of cell-surface spikes and projections that are implicated in cell motility. We demonstrate that fascin is not detectable in normal colonic epithelium, but is dramatically up-regulated in colorectal adenocarcinoma. To test the hypothesis that fascin could participate in tumor invasive behavior, we developed a cell culture model to examine the effect of fascin expression on the adhesive interactions, invasiveness, and differentiation of colonic epithelial cells. We report marked effects on the organization of cell-surface protrusions, actin cytoskeleton, and focal adhesions in the absence of alterations in the protein levels of the major components of these structures. These effects correlate with alterations in cell movements on two-dimensional matrix, and increased invasiveness in three-dimensional matrix. The cells also show increased proliferation and decreased capacity for normal glandular differentiation in collagen gels. We propose that up-regulation of fascin, by promoting the formation of protrusive, actin-based, cell-motility structures, could be a significant component in the acquisition of invasive phe- Epithelial cell differentiation is fundamentally influenced by cell-matrix and cell-cell interactions. [1][2][3] In colonic epithelial cells, both the integrin and cadherin superfamilies of adhesion molecules are important contributors to the establishment of cell polarity and epithelial cell differentiation, and have been shown to play a role in the control of colorectal differentiation in tumor cells. 4,5 This is partly achieved through the formation of intracellular protein assemblies that anchor cytoskeletal actin filaments at defined areas within the cell membrane. In epithelial cells, these zones correspond to integrin-dependent focal adhesions and cadherin-containing adherens junctions and desmosomes. 6 These assemblies also function as important links in the integration of multiple cell signaling pathways. 3 Cell-matrix and cell-cell adhesive interactions normally stabilize the epithelial cell layer and maintain the cells in a nonmigratory state. However, the malignant conversion of epithelial cells involves a phenotypic switch to a migratory state that enables tumor invasion beyond the basement membrane and metastasis. The process of cell migration is poorly understood in epithelial cells, but studies in many types of carcinoma cells have documented increased formation of cell protrusions at cell margins, release of cell-cell contacts, and group movement of sheets of cells. In the models of cell motility that have been developed from studies of fibroblasts, protru...

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Pike C, Rio M-C, Chambon P. Trefoil peptide gene expression in gastrointestinal epithelial cells in inflammatory bowel disease. Scand J Gastroenterol 1992;27 Suppl 193:76-82. Trefoil peptides are a growing group of proteins with interesting structural and functional properties. We have defined the pattern of trefoil peptide gene expression in the ulceration-associated cell lineage (UACL) and in the nearby mucosa in Crohn's disease. In the UACL, human spasmolytic polypeptide (hSP) mRNA is expressed in the acinar and proximal duct cells. while pS2 mRNA and peptide are found in the distal duct cells and in the surface cells. In adjacent mucosa, pS2 mRNA and protein are expressed by goblet cells, with the pS2 peptide concentrated in the area of the Golgi and also in the theca. Ultrastructural immunolocalisation showed the pS2 to be co-packaged in the mucous cell granules before being secreted into the intestinal lumen. In addition, pS2 peptide was demonstrated in local neuroendocrine cells and was also co-packaged with the neuroendocrine granules. The crypts associated with the UACL also showed marked neuroendocrine cell hyperplasia. We conclude that pS2 peptide is secreted locally into the viscoelastic coat covering the intestinal mucosa which surrounds Crohn's disease ulcers. In addition, it is clear that intestinal goblet cells. in addition to producing mucins. are a rich source of regulatory peptides. Moreover, pS2 is clearly co-packaged with ncurosecretory granules. which are released through basal and lateral membranes so that the contained peptides can act in a paracrine manner. These findings are interpreted in terms of the epidermal growth factor/urogastrone released by the UACL. stimulating pS2 gene expression in surrounding cells. The co-packaging of the same secretory protein i n both mucous and neuroendocrine granules, which have markedly different functions, is highly unusual and indicates an important role for pS2 in the secretory process itself, or as a ligand delivered to its receptor via quite different routes. We conclude that the trefoil peptides are widely distributed in the intestine in inflammatory bowel disease. and are thus of considerable potential functional importance. Scand J GastroenterolDownloaded from informahealthcare.com by McMaster University on 11/19/14 For personal use only. Scand J Gastroenterol Downloaded from informahealthcare.com by McMaster University on 11/19/14 For personal use only. Scand J Gastroenterol Downloaded from informahealthcare.com by McMaster University on 11/19/14 For personal use only. 40. 36. Tschopp J, Conselmann A. Proteoglycans and cytolysins in secretory granules of NK cells. Immunol Today 1986;7: 1 3 H . Scand J Gastroenterol Downloaded from informahealthcare.com by McMaster University on 11/19/14 For personal use only.

When hepatocyte regeneration after a two-thirds partial hepatectomy (PH) in rats is blocked by oral gavage of acetylaminofluorene, a proliferation of ductular cells ensues that results in a profusion of neoductules radiating from each portal tract. To examine the possibility that this population of newly emerging cells harbors cells capable of differentiating into hepatocytes, we have looked in these cells for expression of functional markers of hepatocyte commitment at both the RNA and protein levels. Expression of albumin and a-fetoprotein (a-FPI messenger RNA (mRNA) transcripts were sought in situ using antisense riboprobes, and the expression of a number of cytochrome P450 enzymes was examined immunohistochemically. Before any signs of differentiation the ductular cells strongly expressed cytokeratins 7, 8, 18, and 19 in the same manner as authentic bile ducts, but unlike the latter also expressed vimentin. In situ hybridization studies showed that small bile ducts close to the limiting plate, as well as the newly formed ducts, expressed albumin and a-fetoprotein messenger RNAs, and immunocytochemistry showed that the distribution of the respective proteins was similar. Beginning at 1 week after partial hepatectomy, areas of differentiation could be found in the new ducts, with cells resembling either columnar intestinal-type epithelia or hepatocytes. Intestinal-like cells expressed neither albumin, a-FP, nor cytochrome P450 enzymes, whereas ductular cells appearing like hepatocytes with the typical membranous distribution of cytokeratin 8 strongly expressed a variety of cytochrome P450 enzymes normally associated with functional hepatocytes. These observations further support the belief that reactive ductules, sprouted from small ducts, can represent an adaptive response of the liver to replenish lost hepatocytes, al-