Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0017638 (glioma)
 30,880 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A novel human glioma-associated extracellular matrix (ECM) glycoprotein has been identified by murine monoclonal antibody 81C6. The glycoprotein, designated GMEM, is expressed in the ECM of glioma and mesenchymal cell cultures, in the perivascular matrix of endothelial proliferations of human gliomas, and in the stroma of human glioma xenografts in athymic mice, where it has been used as a target antigen for monoclonal antibody tumor localization and radioimaging. We report here on the immunochemical and biochemical characterization of GMEM. Polyacrylamide gel analysis of immunoprecipitated [3H]-leucine- and [3H]-glucosamine-labeled ECM from the human glioma cell line U-251MG has shown that GMEM is a high-molecular-weight macromolecule (Mr approximately 1,000,000) composed of Mr approximately 230,000 disulfide-bonded glycoprotein subunits. Immunoprecipitation, immunoblot, and one-dimensional peptide map analysis have shown that GMEM is distinct from human fibroblast and plasma fibronectin. These results support previous immunohistology and absorption analysis findings, indicating that GMEM is distinct from fibronectin, laminin, and glycosaminoglycans secreted by U-251MG.
 ...
PMID:Immunochemical and biochemical characterization of a glioma-associated extracellular matrix glycoprotein. 406 74

A Mr 58 000 subunit of the opiate receptor has been identified using tritiated fentanyl isothiocyanate, a potent opiate alkylating reagent with specificity for the delta-opiate receptor subclass. The subunit is alkylated in the presence of dextrorphan but not levorphanol. The specifically labelled protein was retained on columns of immobilized wheat germ agglutinin and is therefore presumably a glycoprotein. Partial purification of the Mr 58 000 opiate receptor subunit from neuroblastoma X glioma NG108-15 hybrid cell membranes is described.
 ...
PMID:Identification of a Mr 58 000 glycoprotein subunit of the opiate receptor. 629 66

The murine antiglioma monoclonal antibody 81C6 has been shown to specifically localize in U-251 MG and D-54 MG human glioma subcutaneous and intracranial athymic mouse xenografts expressing the human gliomamesenchymal extracellular matrix glycoprotein GMEM. In paired-label studies 81C6 reached peak levels of localization in subcutaneous and intracranial xenografts in 24 to 48 hours and persisted there for an additional 5 to 7 days before declining. The percent localized 81C6 in U-251 MG subcutaneous xenografts was tumor size dependent ranging from 2% in 200-300 mg tumors to 15% in 1 gram tumors. Subcutaneous xenografts of U-251 MG were readily radioimaged from 1 up to 6 days following administration of 131-I-81C6. The specificity of 81C6 localization has also been demonstrated by tissue autoradiography, elution of radiolabeled 81C6 from tumor xenografts, and in vivo inhibition of radiolabeled 81C6 localization by unlabeled 81C6. D-54 MG intracranial xenografts were permeable to 81C6 and control immunoglobulin but specific localization occurred only with 81C6. Radiolabeled 81C6 monoclonal antibody and U-251 MG and D-54 MG human glioma xenografts provide a useful operationally tumor specific monoclonal antibody tumor localization model for the examination of monoclonal antibody pharmacokinetics, radioimaging, radioimmunotherapy and combined modality therapy in intracranial human glioma xenografts.
 ...
PMID:Monoclonal antibody localization in subcutaneous and intracranial human glioma xenografts: paired-label and imaging analysis. 646 51

With [3H]fucose as a marker, C6 glioma cells in culture released an 85,000 molecular weight molecule into the medium as the major extracellular glycoprotein. The quantity and extracellular/cytoplasmic ratio of this glycoprotein suggest that its cellular processing is different from that of five other released glycoproteins of molecular weights 55,000, 115,000, 130,000, 150,000, and 170,000. Nearly 40% of newly synthesized glycoproteins in the cells was released into the culture medium. Major glycoproteins retained by the cells migrated electrophoretically to molecular weight positions of 82,000, 110,000, 120,000, 140,000, and 160,000, and approximately one-third of these returned glycoproteins were labile to trypsinization. Both synthesis and release of these macromolecules were inhibited more than 95% with cycloheximide treatment, demonstrating that nearly all fucosylation was linked to protein synthesis. Since 40% of all glycoproteins was released under conditions of more than 99% cellular viability, it is likely that these extracellular glycoproteins are physiological products of membrane turnover and secretion, but not of cell lysis. The results provide a basis for the further study of glial differentiation and of shed glioma antigens.
 ...
PMID:Products of cultured neuroglial cells. III. Release of an 85,000 molecular weight glycoprotein by C6 glioma cells in vitro. 711 94

Two normal and seven malignant human glia lines grown in vitro wer labelled by lactoperoxidase catalysed iodination. The labelled cell surface glycoproteins were isolated by lectin affinity chromatography and compared by SDS gel electrophoresis. The glia and the glioma lines possess a common characteristic glycoprotein pattern. Seven glycoproteins in the molecular weight range between 70,000 and 220,000 daltons and several minor components of low molecular weight could be distinguished. The expression of the glycoproteins was independent of the passage number or the growth conditions although the expression of the different glycoproteins showed quantitative differences for the individual cell lines. The differences found in the tumor lines were either due to an amplification or decrease in the expression of the different glycoproteins and/or their accessibility to the lactoperoxidase-catalysed labelling.
 ...
PMID:Surface glycoproteins of normal and neoplastic glia cells in culture. 739 45

Exposure of rat glioma C6 cells to dolichyl phosphate resulted in cell shrinkage followed by nuclear fragmentation and internucleosomal cleavage of genomic DNA, yielding ladder patterns of oligonucleosomal fragments, all characteristics of apoptosis. This phenomenon occurred in a dose and time dependent manner. Dolichol and prenol failed to induce apoptosis. The inhibitors of N-glycosylation, tunicamycin and swainsonine had no apparent effect on dolichyl phosphate-induced apoptosis. Apoptotic changes were also observed in HL-60 cells, SIRC cells and HeLa cells. Thus, dolichyl phosphate functions as a potential apoptosis inducer as well as an essential carrier lipid in the biosynthesis of N-linked glycoprotein.
 ...
PMID:Dolichyl phosphate, a potent inducer of apoptosis in rat glioma C6 cells. 748 3

Tenascin, an extracellular matrix glycoprotein, has been reported to be expressed predominantly on glioma tissue in the CNS, both in a cell associated and an excreted form. Recently, a highly sensitive sandwich type enzyme immunoassay for quantitative determination of tenascin was developed. In the present study, the amount of tenascin in CSF was measured. An increase of tenascin in CSF (> 100 ng/ml) was found in patients with an astrocytic tumour. The concentration was significantly higher (> 300 ng/ml) in high grade astrocytoma (anaplastic astrocytoma and glioblastoma) and a further increase (> 1000 ng/ml) was found in cases of CSF dissemination of high grade astrocytoma. On the other hand, tenascin concentrations were less than 100 ng/ml in non-astrocytic tumours and non-neoplastic neurological diseases, except meningeal dissemination of tumour cells, meningeal stimulation by infection, and subarachnoid haemorrhage. In cases of treated astrocytomas in remission, tenascin was negligible (< 100 ng/ml) in the CSF. The measurement of tenascin in CSF is useful for differential diagnosis of brain tumours and monitoring of astrocytic tumours.
 ...
PMID:Tenascin in cerebrospinal fluid is a useful biomarker for the diagnosis of brain tumour. 752 4

We raised an anti-glioma monoclonal antibody, named G-22, that specifically recognizes a human glioma-associated surface antigen. Proven to be useful for target imaging of malignant gliomas after radioisotope labeling and cerebrospinal fluid diagnosis by enzyme-linked immunospecific assay, G-22 was found to immunoprecipitate an 85-kDa glycoprotein of the human glioma U-251MG cell. We purified this antigen by G-22-coupled cyanogenbromide-activated Sepharose affinity chromatography, and sequence analysis demonstrated that the 54 amino acid residues were identical to positions 55-108 of human CD44. The results show that the smallest spliced form (85 kDa) of CD44 is strongly expressed in glioma cells.
 ...
PMID:Anti-(glioma surface antigen) monoclonal antibody G-22 recognizes overexpressed CD44 in glioma cells. 752 1

Phosphacan is a chondroitin sulfate proteoglycan produced by glial cells in the central nervous system, and represents the extracellular domain of a receptor-type protein tyrosine phosphatase (RPTP zeta/beta). We previously demonstrated that soluble phosphacan inhibited the aggregation of microbeads coated with N-CAM or Ng-CAM, and have now found that soluble 125I-phosphacan bound reversibly to these neural cell adhesion molecules, but not to a number of other cell surface and extracellular matrix proteins. The binding was saturable, and Scatchard plots indicated a single high affinity binding site with a Kd of approximately 0.1 nM. Binding was reduced by approximately 15% after chondroitinase treatment, and free chondroitin sulfate was only moderately inhibitory, indicating that the phosphacan core glycoprotein accounts for most of the binding activity. Immunocytochemical studies of embryonic rat spinal phosphacan, Ng-CAM, and N-CAM have overlapping distributions. When dissociated neurons were incubated on dishes coated with combinations of phosphacan and Ng-CAM, neuronal adhesion and neurite growth were inhibited. 125I-phosphacan bound to neurons, and the binding was inhibited by antibodies against Ng-CAM and N-CAM, suggesting that these CAMs are major receptors for phosphacan on neurons. C6 glioma cells, which express phosphacan, adhered to dishes coated with Ng-CAM, and low concentrations of phosphacan inhibited adhesion to Ng-CAM but not to laminin and fibronectin. Our studies suggest that by binding to neural cell adhesion molecules, and possibly also by competing for ligands of the transmembrane phosphatase, phosphacan may play a major role in modulating neuronal and glial adhesion, neurite growth, and signal transduction during the development of the central nervous system.
 ...
PMID:Interactions of the chondroitin sulfate proteoglycan phosphacan, the extracellular domain of a receptor-type protein tyrosine phosphatase, with neurons, glia, and neural cell adhesion molecules. 752 21

Tenascin glycoproteins constitute a growing family of extracellular matrix molecules that are transiently expressed by astrocytes during the development of the central nervous system (CNS). In some areas, tenascin distribution is discrete and tenascin boundaries delineate emerging functional processing units, for example, in the somatosensory cortex. The intact adult CNS displays low levels of expression and up-regulation of tenascin after lesion or in glial tumors. In vitro studies using the purified glycoprotein, bacterially expressed tenascin fusion proteins, monoclonal antibodies, and defined cell culture models have established that tenascin glycoproteins possess cell-binding sites for neural cells, support neuronal migration and the formation of neurites. On the other hand, tenascin also embodies repulsive, inhibitory properties that could serve to conceal neuronal assemblies and to segregate emerging fiber tracts. These functional properties are encoded by distinct domains of the molecule and suggest that tenascin glycoproteins are involved in neural pattern formation and regeneration. This interpretation is discussed with reference to a recent report that the elimination of the tenascin gene does not cause obvious abnormalities of neural tissues.
 ...
PMID:Tenascin glycoproteins in developing neural tissues: only decoration? 753 Jan 44


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>