Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.3.1 (alkaline phosphatase)
47,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The expression of cell-surface peptidases was examined in two human colon carcinoma cell lines, Caco-2 and HT-29. Enzymic assays revealed the presence of eight cell-surface peptidases on a Caco-2 cell line (passage number 82-88), namely aminopeptidase N, dipeptidyl peptidase IV, peptidyl dipeptidase A (angiotension-converting enzyme), aminopeptidase P, aminopeptidase W, endopeptidase-24.11, gamma-glutamyl transpeptidase and membrane dipeptidase. The presence of dipeptidyl peptidase IV and endopeptidase-24.11 was also confirmed immunochemically. After 15 days culture, the activities of aminopeptidase P, peptidyl dipeptidase A and alkaline phosphatase activities on Caco-2 cells reached a plateau, and that of membrane dipeptidase began to decline. In contrast, aminopeptidase N, dipeptidyl peptidase IV and endopeptidase-24.11 activities were still rising after 26 days in culture. Caco-2 cells of passage number 181-183 were found to lack endopeptidase-24.11, but maintained dipeptidyl peptidase IV expression. Two populations of HT-29 cells were surveyed. Both the standard, undifferentiated population and a differentiated population expressed only three peptidases: dipeptidyl peptidase IV, aminopeptidase W and carboxypeptidase M. In the differentiated HT-29 cells the activity of dipeptidyl peptidase IV after 14-21 days was beginning to plateau whereas aminopeptidase W activity was still rising and that of carboxypeptidase M had begun to decline. These differences in activity profiles observed among this group of cell-surface peptidases indicate that these cell lines, especially Caco-2, are useful models to study the regulation of their expression.
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PMID:A survey of membrane peptidases in two human colonic cell lines, Caco-2 and HT-29. 131 37

HT-29 Human colonic adenocarcinoma cells when grown on a plastic substratum were anaplastic in appearance and failed to express any morphological or biochemical features that were characteristic of intestinal differentiation. Growth of HT-29 cells subcutaneously in the flank of immune deprived mice gave rise to morphologically heterogeneous tumors which were poorly differentiated but contained approximately 11% of cells with an intestinal phenotype: these showed features typical of cell polarization with well-developed microvilli, tight junctional complexes and desmosomes between adjacent cells. The transfer of cells from plastic onto either a fixed (designated 'non-released') or floating (designated 'released') type I collagen gel induced some morphological features typical of intestinal differentiation; for example goblet-like cells were observed after 9 days, but biochemical markers of differentiation were expressed only modestly. The continued subculture of HT-29 cells on collagen type I gels, which were either attached to the plastic or floating in the medium, induced some morphological features of intestinal differentiation and changes in the activity of brush border-associated enzymes. Alkaline phosphatase activity was enhanced from 1.3 x 10(-3) mumoles/mg/min for cells cultured on plastic substrata to 2.1 x 10(-3) mumoles/mg/min when gels were non-released, and 2.9 x 10(-3) mumoles/mg/min when gels were released after 12 days of culture. This was confirmed by electron microscopical visualization of alkaline phosphatase activity. Elevated levels of aminopeptidase activity were also observed on day 12 (plastic = 26 milliunits/mg; non-released gel = 41 milliunits/mg; released gel = 36 milliunits/mg). Similarly, changes occurred in the secretion of carcinoembryonic antigen from 0.96 x 10(-2) micrograms/mg/48 hours by cells cultured on plastic to 2.3 x 10(-2) micrograms/mg/48 hours by cells cultured on floating collagen gels. The effects of permitting HT-29 cells to undergo polarization were tested by culture on inert filter inserts: morphological features of intestinal differentiation were observed although this did not occur until after 21 days. These studies show that optimization of the growth conditions of anaplastic cells in vitro may provide cultures more representative of the tumor in vivo. This model system may be useful for cell biological and pharmacological studies of colon carcinoma.
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PMID:The influence of type I collagen on the growth and differentiation of the human colonic adenocarcinoma cell line HT-29 in vitro. 142 2

The effects of sodium butyrate (NaB) on the response of the RCA human colon carcinoma cell line to transforming growth factor-beta 1 (TGF-beta 1) were examined. NaB induced differentiation, as judged by an increase in cellular alkaline phosphatase, in the RCA cells and this differentiation was accompanied by a decreased growth rate. TGF-beta 1 did not significantly alter the growth or state of differentiation of the RCA cells. The growth rate of cells treated simultaneously with NaB and TGF-beta 1 was similar to that of control untreated cells while the alkaline phosphatase levels remained comparable to cells treated with NaB. Addition of TGF-beta 1 to cells grown in the presence of NaB resulted in a stimulation of growth. Cells pretreated with TGF-beta 1 remained sensitive to the growth inhibitory and differentiation inducing effects of NaB. These results suggest that NaB may alter the expression of proteins responsible for a stimulatory signal response to TGF-beta 1 in RCA cells.
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PMID:Sodium butyrate alters the response of a human colon carcinoma cell line to transforming growth factor-beta 1. 155 5

To investigate the biosynthetic basis for the mosaic expression of brush border enzymes in confluent Caco-2 cells, a human colon carcinoma cell line exhibiting characteristics of adult small intestinal enterocytes, we have obtained a series of clones differing markedly in their growth rates, amounts of transforming growth factor-alpha/epidermal growth factor-like activity released into the culture medium, and sucrase-isomaltase (SI) activity. Other intestinal markers (aminopeptidase N, dipeptidylpeptidase IV, lactase, alkaline phosphatase and 'crypt cell antigen') displayed a much more limited variability in expression, suggesting that the Caco-2 cell clones we have obtained did not differ in their overall ability to differentiate. Immunofluorescence staining, metabolic labelling with radioactive methionine and hybridization analysis of SI mRNA abundance were used to investigate SI synthesis and its regulation in clones endowed with low, intermediate or high sucrase activity. The results obtained have demonstrated heterogeneous SI expression, even in clonal cell lines, and a negative correlation between SI expression and growth factor concentrations in the culture medium, suggesting an autocrine regulation of cell proliferation and differentiation in confluent Caco-2 cells. Pulse-chase experiments using the two clones endowed with the lowest and highest levels of SI activity, followed by immunoprecipitation of labelled SI with epitope-specific antibodies and SDS/PAGE analysis, suggested that both transcriptional and post-translational mechanisms play a role in the regulation of SI expression in intestinal cells.
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PMID:Clonal analysis of sucrase-isomaltase expression in the human colon adenocarcinoma Caco-2 cells. 176 23

The authors have used two immunoalkaline phosphatase methods to study nonhematopoietic tumor tissues of four patients, one each with alveolar cell carcinoma of the lung, renal cell carcinoma, gastric adenocarcinoma, and colon carcinoma. They found, regardless of specific antibodies used, definite enzyme activity in the tumor cells of these four patients. Although it was possible to determine that the tumor cells were epithelial in origin because of their intense staining with antibodies to epithelial cell antigens, control slides labeled with nonimmune mouse ascites also contained cells with definite enzyme activity. In two of these cases, unlabeled smears were stained for alkaline phosphatase and showed that the tumor cells contained endogenous levamisole-resistant enzyme activity. This endogenous enzyme activity is not demonstrable in either the benign cells of these cases or the benign or malignant cells of other control cases. The findings suggest that the immunoalkaline phosphatase methods also have their inherent endogenous enzymic problems. They also suggest that cytochemical demonstration of levamisole-resistant alkaline phosphatase may be a useful cell marker for the identification of tumor cells in serous effusions.
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PMID:Diagnostic significance of levamisole-resistant alkaline phosphatase in cytochemistry and immunocytochemistry. 246 83

The effects of butyrate-mediated differentiation of human colon carcinoma cells on the expression of src-related tyrosine protein kinases were analyzed. The results demonstrate that treatment of a variety of colon carcinoma cell lines with 2 mM sodium butyrate resulted in diminished population doubling rates, altered morphology, decreased anchorage-independent growth, and increased expression of colon epithelial differentiation marker enzymes such as alkaline phosphatase. In butyrate-treated cells, significantly diminished protein kinase activities and abundance of pp60c-src and p56lck were found to parallel the butyrate-induced phenotypic alterations. For the lck gene, the decreased levels in p56lck abundance were found to coincide with diminished levels of steady-state lck mRNAs. In contrast, treatments which arrested the growth of the colon carcinoma cells without inducing differentiation had no effect on the level of expression of these proteins. Furthermore, colon carcinoma cell lines which were found to be resistant to butyrate-induced differentiation showed no change in the kinase activity or abundance of either protein following butyrate treatment. These results indicate that the expression of several src-related kinases in human colon carcinoma can be influenced by the differentiation state of the cells.
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PMID:Alterations in the expression of pp60c-src and p56lck associated with butyrate-induced differentiation of human colon carcinoma cells. 247 6

The inhibitory action of orellanine (3,3',4,4'-tetrahydroxy-2,2'-dipyridyl-1,1'-dioxide), a fungal toxin of Cortinarius orellanus Fr. and C. orellanoides R. Hry., on alkaline phosphatase isoenzymes was studied. Orellanine specifically inhibited alkaline phosphatase activity in LLC-PK1 renal epithelial cell cultures and in the colon carcinoma cell line Caco-2 without affecting gamma-glutamyl transpeptidase activity. Kinetic studies revealed that orellanine acts on renal alkaline phosphatase as a noncompetitive inhibitor, whereas the intestinal and placental isoforms are inhibited competitively.
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PMID:Differential inhibitory action of the fungal toxin orellanine on alkaline phosphatase isoenzymes. 256 29

LoVo, a continuous cell line derived from a human colon carcinoma produces two alkaline phosphatases: the heat-labile, L-homoarginine-insensitive, intestinal form, characteristic of its tissue of origin and the heat-stable, term-placental form, ectopically produced by a variety of tumors. Under basal conditions the activity levels of both enzymes are similar. Hyperosmolality and sodium butyrate induce increased levels of activity of the two alkaline phosphatases in a disparate fashion; whereas hyperosmolality augments the activity of both to the same extent, the effect of butyrate is more pronounced on the activity of the intestinal enzyme. When the two inducers are combined, induction of term-placental alkaline phosphatase is additive and that of the intestinal enzyme is synergistic. The effect of hyperosmolality is blocked by cycloheximide, and induction by sodium butyrate is inhibited by thymidine, cordycepin and cycloheximide. The known alkaline phosphatase inducer, prednisolone, has no effect on the enzymes of LoVo cells. Our results suggest that in these tumor cells the activity levels of the closely homologous term-placental and intestinal alkaline phosphatases appear to be independently controlled.
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PMID:Modulation of alkaline phosphatases in LoVo, a human colon carcinoma cell line. 280 87

HLA class I and II antigen expression was studied in normal mucosa, adenoma and colon carcinoma. Alkaline phosphatase anti-alkaline phosphatase (APAAP) staining techniques were used in cryostatic sections with anti-HLA-ABC and DR,DP,DQ monoclonal antibodies. All normal mucosa were intensely positive for HLA class I antigen expression, while failing to express class II molecules, except in mucosa adjacent to tumors (15/19 cases). All adenomatous polyps expressed HLA class I antigen, while the intensity of class II expression (DR greater than DQ greater than DP) was paralleled by the degree of dysplasia. In colon carcinoma, the loss of class I expression was seen in 4 out of 32 cases, and class II expression was found to be heterogeneous in 16 of these 32 cases (DR greater than DP greater than DQ). No relationship was noted between class II expression and degree of differentiation. However a correlation was seen between HLA-DR antigen expression and degree of invasiveness, mononuclear infiltrate and prognosis, according to Jass's criteria.
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PMID:Class I and II HLA antigen distribution in normal mucosa, adenoma and colon carcinoma: relation with malignancy and invasiveness. 285 3

Twenty human colon carcinoma cell lines were studied for their ability to develop some of the characteristics of the normal intestinal epithelium, e.g., epithelial polarity, presence of the actin-binding protein villin, or the occurrence of an enterocytic differentiation either when cultured under standard conditions, as for Caco-2 cells, or when grown in a glucose-free medium, as for HT-29 cells. Except for the regular presence of villin, which can be considered a marker of the colonic origin of the cells, the cell lines of this study could be classified into four types with regard to their differentiation characteristics. In type 1 (only one cell line, i.e., Caco-2) the cells undergo spontaneously an enterocytic differentiation characterized by a polarization of the cell layer with the formation of domes and the presence of an apical brush border the membrane of which is endowed with hydrolases such as sucrase-isomaltase, lactase, amino-peptidase N, dipeptidylpeptidase IV and alkaline phosphatase. In type 2 (three cell lines: HT-29, HCT-EB, and HCT-GEO) the cells are undifferentiated when grown in the presence of glucose but undergo an enterocytic differentiation when grown in the absence of glucose. In type 3 (eight cell lines: HCT-GLY, HCT-FET, HCT-FRI, HCT-CBS, HCT-ALA, Co-115, HRT-18, and SW-1116) the cells are organized into a polarized monolayer with the formation of domes but without any enterocytic differentiation characteristics, whatever the culture conditions. In type 4 (eight cell lines: HCT-116a, HCT-R, HCT-RCA, HCT-Moser, HCT-8R, SW-480, LS-174T, and Vaco-9P) the cells are organized into a multilayer without any feature of epithelial polarity or enterocytic differentiation, whatever the culture conditions.
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PMID:Epithelial polarity, villin expression, and enterocytic differentiation of cultured human colon carcinoma cells: a survey of twenty cell lines. 334 66


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