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 growth hormone receptor (GHR), a cytokine receptor superfamily member, requires the JAK2 tyrosine kinase for signaling. We now examine functional interactions between growth hormone (GH) and epidermal growth factor (EGF) in 3T3-F442A fibroblasts. Although EGF enhanced ErbB-2 tyrosine phosphorylation, GH, while causing retardation of its migration on SDS-polyacrylamide gel electrophoresis, decreased ErbB-2's tyrosine phosphorylation. GH-induced retardation was reversed by treatment of anti-ErbB-2 precipitates with both alkaline phosphatase and protein phosphatase 2A, suggesting that GH induced serine/threonine phosphorylation of ErbB-2. Both GH-induced shift in ErbB-2 migration and GH-induced MAP kinase activation were unaffected by a protein kinase C inhibitor but were blocked by the mitogen-activated protein kinase/extracellular signal-regulated kinase kinase 1 (MEK1) inhibitor, PD98059. Notably, leukemia inhibitory factor, but not interferon-gamma, also promoted ErbB-2 shift and mitogen-activated protein kinase activation. Cotreatment with EGF and GH versus EGF alone resulted in a 35% decline in acute ErbB-2 tyrosine 1248 autophosphorylation, a marked decline (approximately 50%) in DNA synthesis, and substantially decreased cyclin D1 expression. We conclude that in 3T3-F442A cells, 1) the GH-induced decrease in ErbB-2 tyrosine phosphorylation correlates with MEK1/mitogen-activated protein kinase activity and 2) GH antagonizes EGF-induced DNA synthesis and cyclin D1 expression in a pattern consistent with its alteration in ErbB-2 phosphorylation status.
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PMID:Growth hormone-induced alteration in ErbB-2 phosphorylation status in 3T3-F442A fibroblasts. 1058 92

We studied the effect of two members of the epidermal growth factor (EGF) family--amphiregulin and heparin-binding EGF-like growth factor (HB-EGF)-on cell proliferation, growth factor and growth factor receptor expression, and cell differentiation in two human colon cell lines of varying liver-colonizing potential. The effect of amphiregulin and HB-EGF was assessed both in cells grown on plastic, as well as on cells grown on hepatocyte-derived extracellular matrix (ECM). We found that both colon cell lines were sensitive to HB-EGF stimulation of cell proliferation. Amphiregulin inhibited cell proliferation in KM12 cells and stimulated the strongly metastatic cell line KM12SM to a slight extent. When the cells were cultured on hepatocyte-derived ECM, amphiregulin inhibited the weakly metastatic KM12 and stimulated the growth of KM12SM. HB-EGF synergistically acted with hepatocyte-derived ECM to enhance cell proliferation in both colon cell lines. Expression of ligands of the EGF family, such as transforming growth factor-alpha (TGF-alpha) and amphiregulin, was decreased in both cell lines when cultured on ECM. Hepatocyte-derived ECM decreased expression of cripto in KM12 and increased it in KM12SM cells. Neither cripto nor TGF-alpha mRNA levels was affected by growing the cells in the presence of amphiregulin. However, amphiregulin increased expression of its own mRNA in the weakly metastatic KM12 and decreased it in the strongly metastatic KM12SM when the cells were cultured on plastic. Amphiregulin and HB-EGF stimulated expression of erb-B2 in both cell lines cultured on plastic. Surprisingly, when the cells were grown on hepatocyte-derived ECM, amphiregulin inhibited erb-B2 expression in both cell lines. We observed no effect of amphiregulin on cell differentiation as assessed by alkaline phosphatase expression. Our studies demonstrate one mechanism that could play a role in site-specific metastasis. We found an inhibitory response to an autocrine growth factor in the context of hepatocyte-derived ECM in a weakly metastatic cell and a stimulatory effect of the same growth factor when strongly metastatic cells were cultured on the same ECM.
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PMID:Amphiregulin and hepatocyte-derived extracellular matrix regulate proliferation and autocrine growth factor expression in colon cancer cell lines of varying liver-colonizing capability. 1061 49

We have previously shown that when human umbilical cord blood (UCB) cells are cultured in standard Dexter-type long-term cultures (D-LTC), adherent cells develop forming a discrete net on the bottom of the culture flask. The identity of such cells, however, has not been defined. Accordingly, the major goal of the present study was to characterize the adherent cells developed in standard UCB D-LTC. Cultures were established from 14 UCB samples and from nine bone marrow (BM) samples, as controls. Both UCB and BM cultures were initiated with the same number of mononuclear cells (MNC) (2.5 x 10(6) MNC/ml). After three weeks in culture, adherent cell numbers in UCB D-LTC were 24%-30% of the numbers found in BM cultures. More than 90% of the adherent cells in UCB D-LTC expressed the acid phosphatase enzyme, whereas no alkaline phosphatase-positive cells were observed. This was in contrast to BM D-LTC, in which alkaline and acid phosphatase were expressed by 60%-75% and 20%-45% of the adherent cells, respectively. Immunochemical analysis showed that CD61 (osteoclast marker) and Factor VIII (endothelial cell marker) were not expressed by the adherent cells developed in UCB cultures. Interestingly, the majority of such cells expressed CD1a (dendritic cell marker), CD14, CD68 and CD115 (antigens mainly expressed by macrophagic cells). When the cultures were supplemented with the recombinant cytokines epidermal growth factor, basic fibroblast growth factor, platelet-derived growth factor or granulocyte-macrophage colony-stimulating factor (GM-CSF), only GM-CSF had a significant positive effect on adherent cell number. In order to test for some functional properties of the adherent cells developed in culture, production of stem cell factor (SCF), interleukin 6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) was assessed. IL-6 and TNF-alpha showed elevated levels in UCB D-LTC, whereas SCF levels were always below detection. Finally, analysis of fibroblast progenitors (fibroblast colony-forming units [CFU-F]) showed that these cells were present in BM samples (6 CFU-F/10(5) MNC) and were totally absent in UCB samples. Taken together, the results of the present study indicate that the vast majority of the adherent cells developed in standard UCB D-LTC belong to the macrophage lineage and that fibroblasts seem to be absent. Interestingly, the high proportion of CD1a+ cells suggests that dendritic cells are also present in these cultures.
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PMID:Characterization of the adherent cells developed in Dexter-type long-term cultures from human umbilical cord blood. 1066 71

The role of epidermal growth factor receptors (EGF-R) in osteogenic cell differentiation was investigated using preosteoblastic MC3T3-E1 (MC3T3) cells and osteoblast-like ROS 17/2.8 (ROS) cells. When cultured in the presence of beta-glycerophosphate (GP) and ascorbic acid (AA), MC3T3 cells underwent spontaneous differentiation into osteoblasts which was confirmed as they expressed osteoblast markers such as alkaline phosphatase (ALP), bone sialoprotein (BSP) and osteocalcin (OC). Interestingly, the number of EGF-binding sites decreased during their differentiation into osteoblasts, and the osteogenic protein-1 (OP-1) treatment, which accelerated their differentiation, lowered the number of EGF-binding sites even further. On the other hand, ROS cells with high expression levels of osteoblast markers and no EGF-R, after being transfected with human EGF-R cDNA (EROS cells), expressed numerous EGF-binding sites as well as EGF-R mRNA and protein; in the process, they ceased to express osteoblast markers, indicating their dedifferentiation into osteoprogenitor cells. Both MC3T3 and EROS cells showed increased cell growth in response to EGF, whereas ROS cells did not. These results imply that the EGF/EGF-R system in osteogenic cells has a crucial function in osteoblast phenotype suppression and osteogenic cell proliferation.
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PMID:Down-regulation of osteoblastic cell differentiation by epidermal growth factor receptor. 1092 Feb 19

Akt, when activated by IGF/insulin, can phosphorylate forkhead transcription factors. We undertook this study to determine whether epidermal growth factor (EGF) treatment could produce a signaling cascade resulting in phosphorylation of the forkhead transcription factor FKHR in a breast cancer cell line, MDA-MB-231. After establishing ErbB1, cbl, PI3 kinase and Akt were activated in EGF treated MDA-MB-231, we determined by immunoblot with FKHR antiserum that the electrophoretic mobility of FKHR was retarded after EGF treatment. This mobility retardation was reversible by treatment with alkaline phosphatase, and immunoblot with phospho-Ser256 FKHR antibody further confirmed phosphorylation on an Akt consensus site after EGF treatment. EGF stimulated FKHR phosphorylation was blocked by the PI3 kinase inhibitor LY294002, and the ErbB1 inhibitor AG1478. FKHR immunoblotting after purification of nuclear and cytoplasmic proteins showed that EGF induced a simultaneous increase of FKHR in the cytoplasm and decrease in the nucleus. This finding was confirmed by immunofluorescence staining. Treatment of cells with pharmacological inhibitors of PI3 kinase or ErbB1 blocked this effect. Thus, these results demonstrate the phosphorylation and nuclear exclusion of FKHR after EGF treatment by a PI3 kinase dependent mechanism, and represent the first report of growth factor regulation of endogenous FKHR localization.
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PMID:Phosphorylation and nuclear exclusion of the forkhead transcription factor FKHR after epidermal growth factor treatment in human breast cancer cells. 1103 Jan 46

We produced an immortalized colonic epithelial cell line, MCE301, using fetal mice transgenic for the temperature-sensitive simian virus 40 large T-antigen gene. MCE301 cells showed epithelial-like morphology and maintained tight connections with neighboring cells. The cells grew at a permissive temperature (33 degrees C), but the growth of the cells was significantly prevented at the nonpermissive temperature (39 degrees C). The cells expressed large T-antigen at 33 degrees C but not at 39 degrees C. MCE301 cells were not transformed, as judged by the absence of anchorage-independent growth in soft agar gel and lack of tumor formation in nude mice. Electron microscopic studies showed that the cells formed microvilli-like structures on the cell surface and junctional complexes such as tight junctions and desmosomes between the cells. The cells expressed cytosketal (acidic cytokeratins and actin), basement membrane (laminin and collagen type IV) and junctional complex proteins (ZO-1 and desmoplakin I + II), as judged by specific antibodies. Fetal bovine serum, epidermal growth factor, insulin-like growth factor and insulin significantly increased the cell growth at 33 degrees C. Moreover, MCE301 cells expressed colonic mucin Muc2 mRNA as demonstrated by reverse transcriptase-polymerase chain reaction, indicating that the cells originate from mucus-secreting cells. Alkaline phosphatase, a brush border-associated enzyme, was detected in the cells. Sodium butyrate (2 mM), an inducer of cellular differentiation, markedly elevated alkaline phosphatase activity. Thus, the present mouse colonic epithelial cell line MCE301 possessing these unique characteristics should provide a useful in vitro model of colonic epithelium.
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PMID:Establishment and characterization of a colonic epithelial cell line MCE301 from transgenic mice harboring temperature-sensitive simian virus 40 large T-antigen gene. 1123 98

In mammals, the midportion of the soft tissue of Meckel's cartilage at the degenerating stage forms a ligament known as the sphenomandibular ligament. To clarify the mechanism of formation of this ligament by Meckel's cartilage in mouse, we examined the effects of epidermal growth factor (EGF) on the chondrocytes in terms of the proliferation and differentiation of cells and calcification of the matrix in vivo and in vitro. The effects of EGF were examined by immunohistochemical staining, with EGF-soaked beads, by electron microscopy, and by general histochemical analysis of proteoglycans and calcification. Analysis of labeling with bromodeoxyuridine (BrdU) and the rate of cell growth revealed that EGF enhanced DNA synthesis and the proliferation of Meckel's chondrocytes. Histological findings in organ culture and in cell culture, with and without the application of EGF-soaked beads, revealed that EGF inhibited the differentiation of cells to chondrocytes and induced phenotypic changes in fibroblastic cells. The inhibition of alkaline phosphatase activity that resulted from exposure to EGF was accompanied by prolonged calcification of the matrix. Whole-mount staining revealed that subcutaneous injection of EGF enhanced the disappearance of Meckel's cartilage. Our results suggest a possible mechanism whereby the midportion of Meckel's cartilage remains uncalcified and is rapidly transformed into the sphenomandibular ligament.
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PMID:Formation of the sphenomandibular ligament by Meckel's cartilage in the mouse: possible involvement of epidermal growth factor as revealed by studies in vivo and in vitro. 1138 88

Bone marrow stromal cells (BMSCs) for osteoblast differentiation studies can be obtained by gradient isolation techniques or by directly plating a filtered cell suspension. We compared these two procedures to evaluate whether this step is critical in order to obtain a high number of differentiated colonies. Isolated primary rat BMSCs were cultured in vitro with or without insulin-like growth factor II (IGFII), basic fibroblast growth factor (b-FGF), epidermal growth factor (EGF) or transforming growth factor beta 1 (TGF beta 1), and histochemically and biochemically analysed at different time points. The gradient procedure produced a significantly higher number of colonies capable of osteoblastic differentiation. The growth factors had different effects. In particular, b-FGF and EGF significantly increased the number of Alizarin red S positive colonics, while IGFII and TGF beta I exerted inhibitory effects. Nodules obtained on day 21 showed some alkaline phosphatase positive cells and were Von Kossa-positive. These data demonstrate that more differentiated colonies are obtainable from BMSCs isolated by the gradient procedure.
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PMID:An elevated number of differentiated osteoblast colonies can be obtained from rat bone marrow stromal cells using a gradient isolation procedure. 1169 88

The stromal cell population in bone marrow has been the focus of much attention since it has been shown that this cell population can be expanded and differentiated into cells with the phenotype of bone, cartilage, muscle, stroma, neural, and fat cells. We evaluated umbilical cord blood (UCB) for the presence of these cells. From the mononuclear fraction of UCB, we demonstrated the presence of a subset of cells that have been maintained in continuous culture for more than 6 months (>10 passages). These adherent cell populations express adhesion molecules CD13+, CD29+, and CD44+, but not antigens of hematopoietic differentiation. Exposure of these cells to osteogenic agents resulted in an increase in expression of alkaline phosphatase and the appearance of hydroxyapatite nodules by Von Kossa staining. Incubation with adipogenic agents resulted in morphological change and staining with Oil Red O. In addition, when exposed to basic fibroblast growth factor and human epidermal growth factor the cells underwent changes consistent with cells of neural origin. These changes were demonstrated by a combination of immunofluorescent labeling and Western immunoblots for neural-specific markers. Thus, similar to what has been previously reported with bone marrow, cord blood contains a population of cells that can be expanded in culture and are able to express the phenotype of multiple lineages. Cord blood multilineage cells are slower to establish in culture, have a lower precursor frequency and a lower level of bone antigen expression, and lack constitutive expression of neural antigens when compared to bone marrow, suggesting a more primitive population. Cord blood may prove to be a new source of cells for cellular therapeutics for stromal, bone, and, potentially, neural repair.
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PMID:Multilineage differentiation activity by cells isolated from umbilical cord blood: expression of bone, fat, and neural markers. 1176 Jan 45

Apocrine and eccrine sweat glands are distinct in function, although they are closely related to each other developmentally and morphologically. In certain sweat gland tumors, it is difficult to differentiate between eccrine or apocrine sweat glands. Therefore, this paper reviews histochemical and immunohistochemical markers to differentiate apocrine and eccrine sweat glands with the aim of better understanding the structural and functional characteristics of these sweat glands. Specific markers for apocrine sweat glands are as follows: neuraminidase sensitive anionic sites detected by cationic colloidal gold at pH 2.0, and mitochondrion-like secretory granules that have epidermal growth factor-like antigenicity. The following antibodies react with apocrine sweat glands but not with eccrine sweat glands; the antibodies raised against 70 kDa glycoprotein purified from human milk fat globule membranes, and HMFG-1 (1.10.F3) monoclonal antibody produced by immunizing mice with defatted human milk fat globule membranes. Markers for eccrine sweat glands are as follows: dark cell granules that have chondroitinase ABC sensitive anionic sites detected by cationic gold at pH 2.0 after pretreatment with EGTA, and intercellular canaliculi with high activity of alkaline phosphatase. CEA and GCDFP-15 are expressed in both eccrine and apocrine sweat glands. Anti-EMA monoclonal antibody (E29) stains both eccrine and apocrine sweat glands.
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PMID:Histochemical and immunohistochemical markers for human eccrine and apocrine sweat glands: an aid for histopathologic differentiation of sweat gland tumors. 1176 85


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