The adenomatous polyposis coli tumour suppressor gene regulates c-MYC transcription in colon cancer cells.
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Colonic Neoplasms↗
Biomedical subjects
M Pignatelli
Publications and source records attributed to M Pignatelli.
Vicia faba agglutinin, the lectin present in broad beans, stimulates differentiation of undifferentiated colon cancer cells.
BACKGROUND: Dietary lectins can alter the proliferation of colonic cells. Differentiation is regulated by adhesion molecules which, being glycosylated, are targets for lectin binding. AIMS: To examine the effects of dietary lectins on differentiation, adhesion, and proliferation of colorectal cancer cells. METHODS: Differentiation was assessed in three dimensional gels, adhesion by aggregation assay, and proliferation by 3H thymidine incorporation. The role of the epithelial cell adhesion molecule (epCAM) was studied using a specific monoclonal antibody in blocking studies and Western blots. The human colon cancer cell lines LS174T, SW1222, and HT29 were studied. RESULTS: The cell line LS174T differentiated in the presence of Vicia faba agglutinin (VFA) into gland like structures. This was inhibited by anti-epCAM monoclonal antibody. Expression of epCAM itself was unaffected. VFA as well as wheat germ agglutinin (WGA) and the edible mushroom lectin (Agaricus bisporus lectin, ABL) significantly aggregated LS174T cells but peanut agglutinin (PNA) and soybean agglutinin (SBA) did not. All lectins aggregated SW1222 and HT29 cells. Aggregation was blocked by the corresponding sugars. Aggregation of cells by VFA was also inhibited by anti-epCAM. VFA, ABL, and WGL inhibited proliferation of all the cell lines; PNA stimulated proliferation of HT29 and SW1222 cells. In competition studies all sugars blocked aggregation and proliferation of all cell lines, except that the addition of mannose alone inhibited proliferation. CONCLUSION: VFA stimulated an undifferentiated colon cancer cell line to differentiate into gland like structures. The adhesion molecule epCAM is involved in this. Dietary or therapeutic VFA may slow progression of colon cancer.
Adenocarcinoma↗
Gastrointestinal responses to a panel of lectins in rats maintained on total parenteral nutrition.
Total parenteral nutrition (TPN) causes atrophy of gastrointestinal epithelia, so we asked whether lectins that stimulate epithelial proliferation can reverse this effect of TPN. Two lectins stimulate pancreatic proliferation by releasing CCK, so we asked whether lectins that stimulate gastrointestinal proliferation also release hormones that might mediate their effects. Six rats per group received continuous infusion of TPN and a once daily bolus dose of purified lectin (25 mg. rat-1. day-1) or vehicle alone (control group) for 4 days via an intragastric cannula. Proliferation rates were estimated by metaphase arrest, and hormones were measured by RIAs. Phytohemagglutinin (PHA) increased proliferation by 90% in the gastric fundus (P < 0.05), doubled proliferation in the small intestine (P < 0.001), and had a small effect in the midcolon (P < 0.05). Peanut agglutinin (PNA) had a minor trophic effect in the proximal small intestine (P < 0.05) and increased proliferation by 166% in the proximal colon (P < 0.001) and by 40% in the midcolon (P < 0.001). PNA elevated circulating gastrin and CCK by 97 (P < 0.05) and 81% (P < 0.01), respectively, and PHA elevated plasma enteroglucagon by 69% and CCK by 60% (both P < 0.05). Only wheat germ agglutinin increased the release of glucagon-like peptide-1 by 100% (P < 0.05). PHA and PNA consistently reverse the fall in gastrointestinal and pancreatic growth associated with TPN in rats. Both lectins stimulated the release of specific hormones that may have been responsible for the trophic effects. It is suggested that lectins could be used to prevent gastrointestinal atrophy during TPN. Their hormone-releasing effects might be involved.
Animals↗
E-cadherin and catenins: molecules with versatile roles in normal and neoplastic epithelial cell biology.
E-cadherin and its associated cytoplasmic proteins alpha-, beta-, and gamma-catenin, play a crucial role in epithelial cell-cell adhesion and in the maintenance of tissue architecture. Perturbation in the expression or function of any of these molecules results in loss of intercellular adhesion, with possible consequent cell transformation and tumour progression. The catenins are connected to many structural and functional proteins, which in turn influence their functions. Among these molecules are type 1 growth factor receptors, which along with other molecules are believed to alter the function of catenins through tyrosine phosphorylation. A recent finding is the association between the catenins and the adenomatous polyposis coli gene product (APC). APC mutation is an early event in colorectal carcinogenesis. It may possibly do so through perturbation of the critical cadherin/catenin complex. Further studies of the cadherin/catenin complex and its connections may give insight into the early molecular interactions critical to the initiation and progression oftumours, which should aid in the development of novel therapeutic strategies for both prevention and treatment.
Adenomatous Polyposis Coli Protein↗
Intestinal trefoil factor controls the expression of the adenomatous polyposis coli-catenin and the E-cadherin-catenin complexes in human colon carcinoma cells.
Intestinal trefoil factor 3 (TFF3) is a member of the trefoil family of peptides, small molecules constitutively expressed in epithelial tissues, including the gastrointestinal tract. TFF3 has been shown to promote migration of intestinal epithelial cells in vitro and to enhance mucosal healing and epithelial restitution in vivo. In this study, we evaluated the effect of recombinant TFF3 (rTFF3) stimulation on the expression and cellular localization of the epithelial (E)-cadherin-catenin complex, a prime mediator of Ca2+ dependent cell-cell adhesion, and the adenomatous polyposis coli (APC)-catenin complex in HT29, HCT116, and SW480 colorectal carcinoma cell lines. Stimulation by rTFF3 (10(-9) M and 10(-8) M) for 20-24 hr led to cell detachment and to a reduction in intercellular adhesion in HT29 and HCT116 cells. In both cell lines, E-cadherin expression was down-regulated. The expression of APC, alpha-catenin and beta-catenin also was decreased in HT29 cells, with a translocation of APC into the nucleus. No change in either cell adhesion or in the expression of E-cadherin, the catenins, and APC was detected in SW480 cells. In addition, TFF3 induced DNA fragmentation and morphological changes characteristic of apoptosis in HT29. Tyrphostin, a competitive inhibitor of protein tyrosine kinases, inhibited the effects of TFF3. Our results indicate that by perturbing the complexes between E-cadherin, beta-catenin, and associated proteins, TFF3 may modulate epithelial cell adhesion, migration, and survival.
Adenomatous Polyposis Coli Protein↗
Expression of catenins and E-cadherin during epithelial restitution in inflammatory bowel disease.
Catenins are cytoplasmic proteins associated with E-cadherin, the prime mediator of cell-cell adhesion. Perturbation in any of these molecules results in altered intercellular adhesion, cell differentiation, and increased migration. In this study, the expression and cellular localization of catenins and E-cadherin in inflammatory bowel disease were examined. The expression of E-cadherin; alpha-, beta-, and gamma-catenin; and p120 was evaluated immunohistochemically in 31 paraffin-embedded colonic specimens from 21 patients with ulcerative colitis and Crohn's disease. Loss of normal membranous E-cadherin and alpha-catenin staining was detected at the mucosal edges around epithelial ulcerations in all cases of active ulcerative colitis and in 50 per cent of cases with active Crohn's disease. Reduced expression of p120 protein was also found at the margins of ulcerated mucosa in all cases of active ulcerative colitis and in 75 per cent of those with active Crohn's disease. There was a statistically significant correlation between the expression of E-cadherin, alpha-catenin and p120 and disease activity. There were no changes in beta- and gamma-catenin expression in either ulcerative colitis on Crohn's disease. These findings indicate that altered expression of E-cadherin, alpha-catenin, and p120 occurs during mucosal ulceration in inflammatory bowel disease. These changes may be involved in promoting cell migration during epithelial restitution of the gastrointestinal mucosa.
Cadherins↗
Integrins, cadherins, and catenins: molecular cross-talk in cancer cells.
In the past decade, there have been major advances in the understanding of some of the mechanisms underlying tumour differentiation, invasion, and metastasis, in which cell-cell and cell-matrix adhesion molecules play a critical role. Cadherin/catenin complex and the integrins are the prime mediators of cell adhesion in normal and transformed cells, cadherin/catenin being largely responsible for intercellular adhesion and integrins for cell-extracellular matrix interactions. Intercellular and cell-matrix adhesion mediated by cadherin/catenin and integrins is likely to play a role in the control of both structural morphology and functional differentiation; hence, any loss of this control mechanism may well facilitate the neoplastic process. Indeed, in cancer cells, there is a co-ordinated down-regulation of both integrins and cadherins which correlates with tumour dedifferentiation. However, the expression and cellular localization of catenins do not always correlate with cadherin expression, since the catenins are rather promiscuous molecules which interact not only with E-cadherin, but also with growth regulatory and signalling molecules such as epidermal growth factor receptor and the adenomatous polyposis coli gene product.
Cadherins↗
E-cadherin/catenin complex in benign and malignant melanocytic lesions.
E-cadherin is a calcium-dependent cell-cell adhesion molecule expressed by melanocytes and responsible for their adhesion to keratinocytes in vitro. In this study, the expression of E-cadherin and its associated cytoplasmic proteins alpha-, beta-, and gamma-catenin was evaluated in melanocytic lesions by immunohistochemistry. E-cadherin expression was evaluated in 70 malignant melanomas and the catenins in 35 of these specimens. Twenty benign melanocytic naevi were also evaluated for E-cadherin and catenin expression. In normal epidermis, E-cadherin/catenin immunostaining was localized at the intercellular borders. In melanomas, a differential loss of E-cadherin expression was observed. Membranous E-cadherin staining was absent in dermal nests of melanomas in their radial growth phase and in Clark level II and III lesions, whereas it was present in a high proportion of melanomas in their vertical growth phase, in Clark level IV and V lesions and in metastasizing melanomas. In contrast, superficial compartments of naevi showed membranous E-cadherin immunoreactivity and junctional naevus cell nests displayed heterogeneous or diffuse cytoplasmic staining. Cytoplasmic alpha- and beta-catenin, but not gamma-catenin staining were detected in all benign and malignant lesions. These findings indicate that qualitative changes in the expression and cellular localization of E-cadherin and of alpha-, beta-, and gamma-catenin occur in melanocytic lesions and may reflect different stages in their progression.
Adult↗
Modulation of epithelial cell adhesion in gastrointestinal homeostasis.
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Animals↗
Abnormal expression of p120 correlates with poor survival in patients with bladder cancer.
p120 is a cytoplasmic molecule closely associated with the Ca(2+)-dependent cell-cell adhesion molecule E-cadherin, by forming complexes between the cytoplasmic domain of E-cadherin and the cytoskeleton. Although it has been shown that loss or downregulation of E-cadherin is associated with an invasive and poorly differentiated phenotype in several tumours, there is very little information available concerning p120 expression in malignant disease. We used an avidin-biotin immunoperoxidase technique to examine the immunoreactivity and cellular localisation of p120 and E-cadherin in 68 transitional cell carcinomas (TCC) and 14 normal bladder biopsies and correlated these results with pathological and clinical parameters. E-cadherin and p120 were expressed in a normal membranous pattern in all normal bladder epithelium specimens. Loss of normal surface E-cadherin and p120 expression was found in 52/68 (76%) and 57/68 (84%) tumours, respectively. There was a significant correlation between the loss of normal membranous expression of p120 and increased grade (P < 0.001) and T stage (P < 0.001). The abnormal expression of p120 was correlated with poor survival (P < 0.05). Our data indicate that the E-cadherin-p120 complex may be a useful prognostic marker in bladder cancer.
Aged↗
p53 mutation is a poor prognostic indicator for survival in patients with hepatocellular carcinoma undergoing surgical tumour ablation.
Forty-two patients with hepatocellular carcinoma (HCC) were resected and their tumours were analysed for p53 mutations by GC-clamped denaturing gradient gel electrophoresis (DGGE), single-strand conformation polymorphism (SSCP) and gene sequencing. All the exons have been analysed in this study. Eight of 12 HCCs with cirrhosis due to viral hepatitis and the two patients with sarcomatoid changes displayed p53 mutations. In contrast, no mutation was observed in the fibrolamellar variant (n = 9), non-cirrhotics (n = 13) and alcoholic cirrhosis (n = 6). The mutations observed were in exons 5-8. Two mutations were observed in codons 136 and 213 as well as a T insertion between residues 156 and 157 (exon 5) and these are reported for the first time in HCC. Likewise, the silent mutation polymorphism in codon 213 was noticed in 3 of the 42 patients. Survival analysis of these patients after surgery showed the mean and median survival in patients with wild-type p53 to be 60 and 43 months respectively. In the group with p53 mutations, the mean and median survival was 15 and 12 months. The difference was statistically significant (P= 0.003).
Adolescent↗
Lectins: from basic science to clinical application in cancer prevention.
Many physiological functions are attributable to lectin-carbohydrate interactions. Lectins are currently being studied for their ability to destroy tumour growth by binding to specific carbohydrate motifs on cancer cells. Cell-surface molecules, including growth factor receptors are often glycosylated, and lectins may act by binding to these. Certain lectins effect the proliferation of intestinal epithelial cells. This effect is cell-type and lectin specific and occurs in the intestine of intact animals, in human colonic explants and colorectal cancer cell lines. Lectins present in mammalian tissue are involved in cell-matrix adhesion, differentiation, lymphocyte circulation and immunomodulation. Mammalian lectins contribute to detection, diagnosis and prognosis of tumour cells, and can be targeted for therapy. New lectins of plant and mammalian origin that have one or more of these functions are currently being developed as tools that could be used to target tumour cells.
Journal Article↗
Altered gamma-catenin expression correlates with poor survival in patients with bladder cancer.
PURPOSE: We studied the expression of alpha-, beta-, gamma- catenin and E-cadherin in transitional cell carcinoma (TCC) and normal bladder epithelium and correlated these results with pathological and clinical parameters. MATERIALS AND METHODS: We used an avidin-biotin immunoperoxidase technique to examine the cellular localization of alpha-catenin, beta-catenin, gamma-catenin and E-cadherin in 68 TCC and 14 normal bladder biopsies. RESULTS: E-cadherin, alpha-catenin, beta-catenin and gamma-catenin were expressed in a normal membranous pattern in all normal bladder epithelium specimens. Loss of normal surface E-cadherin, alpha-catenin, beta-catenin and gamma-catenin expression was found in 52/68 (76.4%) tumors, 57/68 (83.8%) tumors, 54/68 (79.4%) tumors and 54/68 (79.4%) tumors (p <0.001). There was a significant correlation between the loss of normal membranous expression of catenins and E-cadherin and increased grade (p <0.05). A highly significant correlation was observed between the loss of expression of E-cadherin, alpha-catenin and gamma-catenin, but not beta-catenin, with increased TNM stage (p <0.05). The abnormal expression of gamma-catenin as well as E-cadherin was correlated with poor survival (p <0.05). CONCLUSIONS: E-cadherin-gamma-catenin complex may be a useful prognostic marker in bladder cancer. Work is in progress to establish whether normal membranous catenin expression can be enhanced by gene transfer or biological therapy to induce a less invasive and metastatic phenotype.
Aged↗
Beta-catenin mutations in cell lines established from human colorectal cancers.
beta-catenin has functions as both an adhesion and a signaling molecule. Disruption of these functions through mutations of the beta-catenin gene (CTNNB1) may be important in the development of colorectal tumors. We examined the entire coding sequence of beta-catenin by reverse transcriptase-PCR (RT-PCR) and direct sequencing of 23 human colorectal cancer cell lines from 21 patients. In two cell lines, there was apparent instability of the beta-catenin mRNA. Five different mutations (26%) were found in the remaining 21cell lines (from 19 patients). A three-base deletion (codon 45) was identified in the cell line HCT 116, whereas cell lines SW 48, HCA 46, CACO 2, and Colo 201 each contained single-base missense mutations (codons 33, 183, 245, and 287, respectively). All 23 cell lines had full-length beta-catenin protein that was detectable by Western blotting and that coprecipitated with E-cadherin. In three of the cell lines with CTNNB1 mutations, complexes of beta-catenin with alpha-catenin and APC were detectable. In SW48 and HCA 46, however, we did not detect complexes of beta-catenin protein with alpha-catenin and APC, respectively. These results show that selection of CTNNB1 mutations occurs in up to 26% of colorectal cancers from which cell lines are derived. In these cases, mutation selection is probably for altered beta-catenin function, which may significantly alter intracellular signaling and intercellular adhesion and may serve as a complement to APC mutations in the early stages of tumorigenesis.
Amino Acid Sequence↗
Aberrant E-cadherin and alpha-catenin expression in prostate cancer: correlation with patient survival.
E-cadherin maintains the normal differentiated phenotype in epithelial cells; this function is partly mediated by alpha-catenin, which links E-cadherin to the cell cytoskeleton. Dysfunction of E-cadherin in vitro and in vivo is associated with an invasive phenotype. However, the role of alpha-catenin is largely undetermined. We analyzed the expression of E-cadherin and alpha-catenin in prostate cancer to assess the relationship of abnormal expression to stage, grade and survival. E-cadherin expression was evaluated in 99 prostate cancers. In 79 of those specimens, alpha-catenin was also assessed. In benign prostatic epithelium, both E-cadherin and alpha-catenin were expressed uniformly at the cell membrane. Abnormal E-cadherin expression was found in 56% of cancer specimens, whereas alpha-catenin expression was abnormal in 42%. Abnormal expression of each molecule was significantly correlated with Gleason score (P < 0.0001) and the ratio of resection chippings infiltrated by tumor (P < 0.0001). E-cadherin expression was also associated with the extent of disease on the initial bone scan (P = 0.017). Univariate analysis showed significantly lower survival rate for patients with abnormal E-cadherin (P = 0.0003) or alpha-catenin expression (P = 0.031). Multivariate regression analysis showed that the prognostic value of E-cadherin was independent of tumor grade but not of metastasis. These results suggest that perturbation of cell-cell adhesion is involved in the progression of prostate cancer and that analysis of E-cadherin expression may be clinically useful.
Aged↗
Inhibition of growth and enhancement of differentiation of colorectal carcinoma cell lines by MAb MR6 and IL-4.
We have previously shown that expression of gp200-MR6, a molecule that is functionally associated with the interleukin-4 receptor (IL-4R), is lost from breast carcinoma cells as malignancy increases. Here we have analysed a series of colorectal carcinoma cell lines and show a similar decrease with increasing malignancy. Moreover, analysis of the HRA-19 cell line, which can exhibit a poorly or a well-differentiated phenotype according to culture conditions, shows that gp200-MR6 is weakly expressed on the former but strongly expressed on the latter. Functional analysis using either IL-4 or monoclonal antibody (MAb) MR6 and the well-differentiated cell line SW1222 revealed that MAb MR6 acts as an agonist for IL-4, with both reagents causing a dose-dependent inhibition of cell division, but greatly enhancing the glandular differentiation of SW1222 in three-dimensional collagen gels. These observations suggest that the gp200-MR6 molecule may act as the product of a tumour suppressor gene and that its loss may be a primary event in tumourigenesis.
Antibodies, Monoclonal↗
Fibroblast growth factor 1 and fibroblast growth factor 2 immunoreactivity in gastrointestinal tumours.
Acidic and basic fibroblast growth factors (FGF-1 and FGF-2) are mitogenic polypeptides that may play a role in autocrine and paracrine growth control of malignant tumours. We have examined the expression of FGF-1 and FGF-2 in a series of 41 colorectal tumours (24 adenomas, 17 adenocarcinomas) and 50 gastric adenocarcinomas (23 intestinal, 27 diffuse), using immunohistochemistry. Whereas the FGF-1 distribution was cytoplasmic, FGF-2 was restricted to the nuclei of the epithelial cells. FGF-1 immunoreactivity was detected in all samples (100 per cent), whereas FGF-2 immunoreactivity was seen in 17 adenomas (71 per cent), 13 colorectal carcinomas (76 per cent), and 29 gastric carcinomas (58 per cent). Compared with the normal mucosa, FGF-1 was overexpressed in 42 per cent of colorectal adenomas, 76 per cent of colorectal cancers, and 54 per cent of gastric cancers. Conversely, FGF-2 expression was reduced in 16 (66 per cent), 8 (47 per cent), and 40 (80 per cent) adenomas and colorectal and gastric samples, respectively. We found a significant correlation only between reduced FGF-2 and gastric tumour grade. These data indicate that FGF-1 overexpression occurs in a large proportion of human colorectal and gastric cancers. This may play a role in the progression of these tumours. The topographic variation in FGF-2 expression between normal (nuclear) and tumour (cytoplasmic) cells implies a corresponding functional change that may in turn facilitate tumour growth.
Adenoma↗
E-cadherin (E-cad) expression in duct carcinoma in situ (DCIS) of the breast.
E-cadherin (E-cad) is an epithelial cell-cell adhesion molecule whose loss or reduced expression is associated with a more invasive tumour phenotype. Ninety-six cases of screen detected pure ductal carcinoma in situ (DCIS) were analysed immunocytochemically for expression of E-cad using the HECD-1 mouse monoclonal antibody. The in situ component in each case was classified on the basis of cytonuclear grade, extent of necrosis, Van Nuys classification and a newly devised Cardiff classification. The amount of E-cad expression was assessed semi-quantitatively using an intensity distribution method. There is significantly more expression of E-cad in well-differentiated DCIS when compared with poorly differentiated DCIS and this finding is highly significant (P < 0.001) irrespective of the classification system used. These findings suggest that progressive loss of E-cad expression may occur at an early stage of breast cancer development.
Breast Neoplasms↗