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:3.2.1.26 (invertase)
4,927 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Adenocarcinoma of the colon is one of the most prevalent and lethal of all human malignancies. The early diagnosis and management of this disease could be improved if biological markers, whose expression was restricted to malignant colon cells, were identified. Sucrase-isomaltase is a glycoprotein hydrolase expressed throughout the small intestine and fetal colon but not in the normal adult colon. This study shows that the expression of enzymatically active sucrase-isomaltase is a ubiquitous property of primary and metastatic colon adenocarcinoma. Significant sucrase enzyme activity (i.e., greater than 5 mU/mg protein) was observed in 16 colon carcinomas but not in adjacent normal colon mucosa. Sucrase-isomaltase messenger RNA was identified in all tumors using reverse transcriptase polymerase chain reaction. Using a quantitative polymerase chain reaction analysis, this study shows that the amount of sucrase-isomaltase messenger RNA in tumors examined (3.4 x 10(-8) to 3.19 x 10(-7) micrograms/micrograms total RNA) was greater than in adjacent mucosa (0 to 3.4 x 10(-8) micrograms/micrograms total RNA). This induction of sucrase-isomaltase messenger RNA and enzyme activity was corroborated by immunostaining. Of 30 colon adenocarcinomas examined, 80% were positive for sucrase-isomaltase. In addition, all colon carcinoma metastases examined were positive for sucrase-isomaltase. The staining pattern was distinct and demarcated tumor cells from the surrounding histologically normal tissue. No sucrase-isomaltase staining was seen in normal mucosa from the same patients. With the exception of lung, no sucrase-isomaltase immunostaining was observed in a variety of examined noncolonic adenocarcinomas. Thus, the specificity and ubiquity of sucrase-isomaltase expression in adenocarcinomas of the colon can be exploited to improve the clinical management of this disease. In addition, studies on the structure of the sucrase-isomaltase gene and its regulatory elements should contribute toward understanding the alteration of gene expression by oncogenic transformation of the colonic mucosa.
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PMID:Expression of enzymatically active sucrase-isomaltase is a ubiquitous property of colon adenocarcinomas. 170 85

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

This report describes a technique for studying the adherence and growth of Giardia intestinalis trophozoites (strains PARIS/86/LCF/1, PARIS/86/LCF/2 and PARIS/88/LCF/8) using the human colon carcinoma cell line Caco2. Giardia trophozoites were cultured with Caco2 cells in a modified HSP3 culture medium. The biochemical differentiation of Caco2 cells was established by an increase in sucrase isomaltase activities to values of 4.51 +/- 0.90 and 10.39 +/- 3.00 milliunits/mg protein for 8- and 12-day-old cultures, respectively. Giardia, adherence to 8- and 12-day-old Caco2 cells reached a value of greater than 75% after 60 and 30 min, respectively. Adherence diminished significantly at 24 degrees C and was almost undetectable at 4 degrees C. Depletion of divalent cations reduced the proportion of adherent trophozoites by up to 46%. Adherence was pH-independent between pH 6.0 and 7.6. Parasite growth increased when Caco2 cell monolayers were used instead of axenic cultures. This in vitro human cell model may contribute to the study of the mechanisms and factors involved in the host-parasite interaction.
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PMID:Adherence and multiplication of Giardia intestinalis on human enterocyte-like differentiated cells in vitro. 221 20

The purpose of this work was to investigate whether sucrase-isomaltase from enterocyte-like differentiated human colon carcinoma cell lines carries blood group antigens of the ABH system. Six cultured lines of blood group A (HT-29, SW-480, Co-115) or O phenotype (Caco-2, HRT-18, HCT-8R) were studied. Only HT-29 cells grown in the absence of glucose (HT-29 Glc-) and Caco-2 cells express an enterocytic differentiation with the presence of sucrase-isomaltase on the apical surface of the cells. Binding of anti-A antibodies to HT-29 Glc- and of UEA-I to Caco-2 cells gave the same apical immunofluorescence pattern of staining as did anti-sucrase-isomaltase antibodies, whereas only a membrane binding was observed in nondifferentiated cells. Sucrase-isomaltase immunoisolated from HT-29 Glc- and Caco-2 cells reacted with anti-A antibodies and Ulex europaeus agglutinin-I (UEA-I), respectively, at sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblot. Immunoprecipitation of solubilized brush border-enriched fractions from the same cells with UEA-I or anti-A antibodies resulted in an inhibition of sucrase activity which reached congruent to 80% for Caco-2 cells with UEA-I and approximately equal to 50% for HT-29 cells with anti-A antibodies. Similar results were obtained in the corresponding tumors in nude mice: anti-A antibodies in HT-29 and UEA-I in Caco-2 tumors bound to the same apical structures as did anti-sucrase-isomaltase antibodies; sucrase-isomaltase immunoisolated from the tumors bound anti-A antibodies (HT-29) or UEA-I (Caco-2). These results support the hypothesis that sucrase-isomaltase from enterocyte-like differentiated human colon cancer cells carries blood group antigens of the ABH system. These findings suggest that colon cancers which have been shown to display an apical pattern of expression of ABH antigens should be screened for their possible enterocytic differentiation.
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PMID:A and H blood group antigens as markers of sucrase-isomaltase from the enterocyte-like differentiated human colon carcinoma cell lines HT-29 and Caco-2. 243 17

The human colon carcinoma cell line CaCo-2, grown in vitro under standard culture conditions and in the absence of differentiation inducers, spontaneously exhibits structural and functional characteristics of mature small bowel enterocytes. Differentiation is complete at late confluency. High activities of ornithine decarboxylase and diamine oxidase are present in enterocytes. Although these enzymes are involved in polyamine metabolism and therefore in cell replication, their function in small bowel epithelium remains to be defined. In this study ornithine decarboxylase and diamine oxidase activities were assessed in CaCo-2 cells at different stages of proliferation and differentiation. Diamine oxidase was also assayed in spent culture media to assess its spontaneous release by CaCo-2 cells. The trigger effect of medium replacement on ornithine decarboxylase activity was also investigated. Cell growth and cell cycle kinetics were determined by hemocytometric cell count and [3H]thymidine labeling index. Sucrase activity was assayed to evaluate brush-border functional maturation. Elevated ornithine decarboxylase activity was recorded during the replication phase (highest value 0.3 +/- 0.02 U/mg) characterized by high thymidine labeling index (43%), and was greatly enhanced by medium replacement (2.1 +/- 0.3 U/mg). Diamine oxidase activity was low in both cells and medium during the active phase of cell growth, and during the differentiation period it progressively increased (highest value 499 +/- 78 U/mg) along with sucrase activity. The high diamine oxidase activity recorded in the medium (highest value 1292 +/- 310 U/ml) and the evidence of diamine oxidase secretion through the basolateral membrane of the cells cultured on porous filters support the hypothesis of an extracellular role of intestinal diamine oxidase. The CaCo-2 cell line, which shows several analogies with small bowel enterocytes, can be proposed as an interesting in vitro model for studying many aspects of cell replication and differentiation depending on polyamine metabolism.
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PMID:Ornithine decarboxylase and diamine oxidase in human colon carcinoma cell line CaCo-2 in culture. 250

Human colon carcinoma (HT-29) cells were examined for their capacity to bind and respond to 1,25-dihydroxycholecalciferol [1,25-(OH)2D3]. These cells are known to differentiate and increase their population doubling time when galactose is substituted for glucose in their media. High-affinity and specific binding of 1,25-(OH)2[3H]D3 was observed in extracts of these cells grown in glucose. The binder sedimented in sucrose gradients and eluted from DEAE-cellulose columns in a manner indistinguishable from rabbit intestinal 1,25-(OH)2D3-receptor. Smaller amounts of this binder were seen in HT-29 cells grown in galactose. Both glucose-fed and galactose-fed cells exhibited a dose-dependent decrease in growth rate on exposure to 10(-12) to 10(-6) mol/L 1,25-(OH)2D3. Ultrastructural examination of galactose-fed and glucose + 1,25-(OH)2D3-treated cells showed enterocytic differentiation and features that were not distinguishable between these groups. Sucrase activity was higher in galactose-fed cells and did not change with 1,25-(OH)2D3 treatment. However, the lower sucrase activity in glucose-fed cells increased after exposure to 10(-8) mol/L 1,25-(OH)2D3. These results indicate receptor content and bioresponsivity to 1,25-(OH)2D3 in a human enterocytic cell line, suggesting that it will be a useful model for the study of the mechanisms of action of this sterol.
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PMID:Receptors for and bioresponses to 1,25-dihydroxyvitamin D in a human colon carcinoma cell line (HT-29). 255 92

Although sucrase-isomaltase appears in the small intestine at quite different stages of development in man as compared with most mammals, we find that in human embryo also the appearance of sucrase-isomaltase mRNA closely parallels that of sucrase and isomaltase activities, as we have previously found to be the case in baby rabbits. Also, in the proximal-distal gradient of human embryonic intestine (proximal small intestine greater than distal small intestine greater than colon) the levels of these enzyme activities and those of the corresponding mRNA correlate closely. Finally, glucocorticosteroid treatment of a human colon carcinoma cell line (Caco-2) in vitro or of baby rabbits in vivo leads to a parallel increase of both sucrase and isomaltase activities and of sucrase-isomaltase mRNA. We conclude that in man also, in spite of the different timing in development, the biosynthesis of sucrase-isomaltase is most likely to be controlled at the level of transcription or perhaps of the mRNA stability.
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PMID:The biosynthesis of intestinal sucrase-isomaltase in human embryo is most likely controlled at the level of transcription. 342 4

The aim of the study was to ascertain whether the exposure to ethanol of human colon carcinoma CaCo-2 and HT-29 cell lines affects the differentiation process. As an index of enterocytic differentiation, the expression of sucrase, alkaline phosphatase, alpha 2,6-sialyltransferase toward the N-acetyllactosaminic sequence, and beta 1,4-N-acetylgalactosaminyltransferase (beta 1,4GalNAc-transferase) was examined. The latter enzyme is responsible for the biosynthesis of Sda carbohydrate histo-blood antigen, which mainly occurs in human colonic cells; its expression in CaCo-2 cells depends strictly on the enterocytic differentiation. The addition of ethanol in the culture medium resulted in a significant increment of sucrase and alpha 2,6-sialyltransferase activities in both cell lines, as well as the beta 1,4GalNAc-transferase activity in CaCo-2 cells and alkaline phosphatase activity in HT-29 cells. The increment was dose-dependent in the range between 50 and 200 mM ethanol and evident after 2 days of exposure in both cell systems. These results support the notion that, as occurs for cell lines of different origin, the ethanol in vitro positively affects the differentiation of intestinal cells, namely along the enterocytic lineage. The putative mechanism by which ethanol interferes with the maturation process of colonic cells is discussed.
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PMID:Effect of ethanol on human colon carcinoma CaCo-2 and HT-29 cell lines during the maturation process. 769 34

We have investigated the expression of protein kinase C (PKC) and protein kinase A (PKA) during the phases of growth and differentiation of the human colon carcinoma Caco-2 cells. We studied whether differentiation correlated with the responsiveness to cAMP and with an increased transport of the catalytic subunit of PKA into the nucleus. Also, we evaluated whether this phenomenon was affected by PKC activity. High levels of activated PKC were found in the plasma membranes of replicating cells. When the cells began to differentiate, plasma membrane-activated PKC decreased, while the cytosolic fraction increased. On the contrary, PKA holoenzyme increased during differentiation, along with the transport of its catalytic subunit into the nucleus. Both types I and II kinase A holoenzymes increased during differentiation, with maximal type II activity found when cells were fully differentiated. In replicating preconfluent cells, the inhibition of PKC by high dose phorbol 12-myristate 13-acetate or sphingosine increased the amount of both PKA catalytic subunit in the nucleus and sucrase activity. During differentiation, 8-Bromo-cAMP increased PKA catalytic subunit in the nucleus and apoliprotein A1 mRNA levels. These effects were inhibited by low-dose phorbol 12-myristate 13-acetate, which activates PKC in the plasma membranes. Our data suggest that PKC is activated in proliferating Caco-2 cells. The inhibition of PKC induces the transport of PKA catalytic subunit into the nucleus and the expression of the differentiation markers. Differentiated Caco-2 cells show a lower activation of PKC and an increased transport of the catalytic subunit of PKA into the nucleus.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The enterocyte-like differentiation of the Caco-2 tumor cell line strongly correlates with responsiveness to cAMP and activation of kinase A pathway. 781 34

In this study we have examined the role of insulin-like growth factor-II (IGF-II) in the differentiation of the CaCo-2 human colon carcinoma cell line. We have shown previously that IGF-II is an autocrine growth factor for CaCo-2 cells. IGF-II expression is high in proliferating, undifferentiated CaCo-2 cells and markedly decreases when cells become confluent and start to differentiate. To evaluate whether differentiation of CaCo-2 cells depends on an IGF-II related pathway, we treated cells with a blocking antibody to the IGF-I receptor that mediates most IGF-II biological effects. Treatment of preconfluent CaCo-2 cells with this antibody decreased by 40% autonomous cell proliferation and induced differentiation as shown by an increase in sucrase isomaltase activity and apolipoprotein A-I (apoA-I) mRNA levels. To examine the significance of autocrine IGF-II production in CaCo-2 cell differentiation, we generated stable CaCo-2 cell lines that constitutively express rat IGF-II under the control of a Rous sarcoma virus promoter. Sustained expression of IGF-II resulted in: (a) increased proliferative rate; (b) high IGF-I receptor number, even after reaching confluence; (c) increased capability of anchorage-independent growth; (d) inhibition of the expression of apoA-I and SI mRNAs. Analysis of several independent IGF-II-transfected clones showed an inverse correlation between IGF-II mRNA levels and expression of the differentiation markers, the cells expressing the higher levels of the transfected IGF-II being the less differentiated ones. Our data suggest that perturbation of IGF-II-mediated cell proliferation interferes with the enterocyte-like differentiation pathway of CaCo-2 cells.
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PMID:Constitutive insulin-like growth factor-II expression interferes with the enterocyte-like differentiation of CaCo-2 cells. 862 97


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