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)

The immunolocalization of type I, III and IV collagens and fibronectin in two rat glioma cell lines in vitro (BT4C and BT4Cn) is described. In addition, antibodies against denatured type I and III collagens were used to study breakdown products of native type I and III collagens. For the BT4C cells, the extracellular matrix expression in monolayer cultures and in multicellular tumor spheroids was compared. Type IV collagen was strongly expressed in BT4C tumor spheroids but was negative in the corresponding monolayer cultures. Denatured type I collagen was found both in monolayers and in spheroids of BT4C, suggesting either a rapid turnover (i.e., synthesis and immediate breakdown) of type I collagen or an altered collagen gene transcription. Both cell lines were negative for native type I and III and denatured type III collagen. Fibronectin was strongly expressed in both cell lines. Supporting the immunofluorescence data, the hydroxyproline content in the tumor spheroids was twice the amount found in monolayer cultures. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis combined with immunoblotting also verified the immunostaining experiments, showing that glioma spheroids and injected tumor cells have the potential for fibronectin and collagen production, given the appropriate growth conditions.
 ...
PMID:Immunocytochemical characterization of extracellular matrix proteins expressed by cultured glioma cells. 267 Feb 3

Adult injured optic nerves of mammals show an increased distribution of laminin in the extracellular matrix after application of soluble substances in the form of conditioned media originating from growing nerves (Zak, et al., 1987). This increase could result from direct or an indirect activation of glial cells or from activation of other cellular elements. In the present study, we show that the conditioned media derived from regenerating fish optic nerves contain factors that directly modulate the level of laminin in C-6 glioma cells. The identity of the laminin was confirmed by metabolic labeling of the treated cells with [35S]methionine and by subsequent immunoprecipitation and gel electrophoresis. The level of other extracellular matrix proteins, such as fibronectin, is also increased. The significance of the presence of glial-activating substances in the conditioned media of regenerating nerves for the process of regeneration is discussed.
 ...
PMID:Conditioned media of regenerating fish optic nerves modulate laminin levels in glial cells. 270 45

Neurite promoting activities (NPFs) are essential factors in neuronal differentiation. Some of them are associated with proteins of the extracellular matrix (ECM). C6 cells, a rat glioma cell line, release NPF activities into the cell culture medium. We used antibodies against ECM-proteins for enrichment and partial characterization of these activities. Results show that, (1) C6 cells express and release laminin; (2) the C6-laminin consists of 260 kD chains only and is therefore different from typical basal lamina laminin (220 and 440 kD chains), but comparable to other laminins of glial origin (chains in the 200 kD range only); (3) C6-laminin partially purified by affinity chromatography shows NPF-activity; (4) laminin concentration in C6 cell-conditioned medium is not sufficient to account for the total neurite promoting activity of the medium, and (5) in addition to laminin C6 cells express and release fibronectin and possibly type IV collagen.
 ...
PMID:Laminin and other basal lamina proteins with neurite promoting activity in medium conditioned by C6 glioma cells. 271 77

Immunohistochemical studies of astrocytoma tissue have predominantly shown fibronectin (FN) positivity restricted to vessels and glial fibrillary acidic protein (GFAP) positivity in the parenchyma. Cultured glioma cell lines, however, express both FN and GFAP. We measured the DNA content of explants of gliomas to determine if the ploidy of the FN-positive and GFAP-positive cells differed. Thirty-three explants from four high grade gliomas were cultured on slides. FN and GFAP markers were determined by double immunofluorescence. The slides were stained by the Feulgen method, the explants relocated and the DNA content measured by microdensitometry using the CAS-100 instrument. Human leukocytes applied to the slides were used as a diploid standard. Eleven GFAP-positive explants were hyperdiploid and one hypodiploid. Five FN-positive explants were diploid, three hypodiploid and ten hyperdiploid. One FN-positive explant was biclonal with aneuploid subpopulations. Two hyperdiploid explants, each of which had monoclonal histogram patterns, expressed both FN and GFAP. We conclude that most FN-positive cells, in addition to GFAP-positive cells, from cultured gliomas represent neoplastic cells. These may be present in the tumor in low numbers or may result from marker switching in culture.
 ...
PMID:DNA content and marker expression in human glioma explants. 282 64

We established and characterized five cell lines derived from human malignant gliomas (four glioblastomas multiforme and one highly anaplastic astrocytoma). All cell lines exhibited tumor cell morphology and growth kinetics, and anchorage-independent growth in soft agar. Cytogenetic analysis revealed significant aneuploidy in all five cases as well as clonal chromosomal alterations unique to each cell line. No cell line was tumorigenic in athymic mice. Two of the cell lines were sensitive to carmustine (BCNU) in monolayer and soft-agar cultures. Electron microscopy showed marked variability between cell lines in the number and structure of intracytoplasmic organelles; SF-126 formed collagen fibers in vitro. Immunohistochemical analysis of the surgical specimens showed variable expression of glial fibrillary acidic protein (GFAP) in malignant astrocytes; positive immunostaining for glycoproteins of the extracellular matrix was found predominantly in perivascular regions. In early-passage cultures, only cell line SF-295 expressed GFAP; at establishment, none of the cell lines expressed GFAF or glutamine synthetase. Fibronectin and laminin were expressed by all cell lines in early-passage culture, but expression of these glycoproteins at establishment was variable. Only SF-126 was positively identified by immunostains for procollagen III; this was also the only cell line in which DEAE-cellulose chromatography and SDS-PAGE demonstrated interstitial collagen synthesis. These well-characterized glioma-derived cell lines may now serve as useful tools with which to study the cell biology of gliomas. The synthesis of interstitial collagen by a glioma-derived cell line may suggest a derivation from vascular mesenchymal elements, either reactive or transformed, in the original heterogeneous malignant glioma, rather than from a glial precursor cell.
 ...
PMID:Establishment and characterization of five cell lines derived from human malignant gliomas. 282 96

A potential mechanism for valproate (VPA)-induced increases in glial cell-substratum adhesivity has been demonstrated. Metabolically labelled glioma (C6) and primary astrocytes showed a statistically significant accumulation of protein when cultured in the presence of therapeutic concentrations of VPA (1 mM). This was mainly accounted for by a 10-fold increase in the production of a single polypeptide of 43 kDa molecular weight. Fractionation studies and metabolic labelling with N-acetyl-D-mannosamine showed this to be a sialoglycoprotein which was plasma membrane-bound. VPA-induction of the polypeptide was apparently specific to glioma and primary astrocytes and was not observed in neuroblastoma (neuro-2a), fibroblasts (3T3), pituicytes (GH3) and epithelial cells (NCTC). The 43 kDa component of glia was demonstrated to be the receptor for type IV collagen by binding metabolically labelled and solubilised cells to Sepharose beads which had been individually coated with laminin, fibronectin and type IV collagen. The protein has also been shown to be a heat shock product as metabolically labelled glioma showed a 10-fold increase in its expression when cultured at 42 degrees C. This heat shock induced expression was transient and was in marked contrast to that seen with VPA where it increased with time and was sustained. The expression of 43 kDa is suggested to arise by VPA and heat shock induced delays in cell cycle progression and this is discussed in relation to teratogenic action.
 ...
PMID:The anticonvulsant sodium valproate specifically induces the expression of a rat glial heat shock protein which is identified as the collagen type IV receptor. 284 60

A comparative immunocytochemical study was carried out on intracerebral and extracranial gliomas of the rat produced by intracerebral injection of low (10th) and high (40th) in vitro passages of neoplastic glial cells. The cells injected were a neoplastic astrocytic clone-A15 A5-derived from a mixed glioma induced transplacentally by N-ethyl-N-nitrosourea (ENU) in a BD-IX rat. An inverse relationship was seen between the expression of the astrocytic markers glial fibrillary acidic protein (GFAP) and glutamine synthetase (GS) at low and high passage: GFAP decreased with increasing passage while GS increased. The distribution of vimentin, the major cytoskeletal component of immature glia, was constant, irrespective of passage--a feature consistent with previous in vitro findings. The expression of laminin by both reactive and neoplastic astrocytes increased with increasing passage, while high magnification examination revealed the presence of the glycoprotein fibronectin on the cell-surfaces of A15 A5-derived tumour cells. Both neoplastic and reactive astrocytes expressed S-100 protein with a higher proportion of positive cells in extracranial tumours. Occasional cells, probably actively phagocytizing populations of reactive astrocytes and macrophages, were positive for alpha-1-antitrypsin. None of the neoplastic cells expressed the oligodendrocyte marker carbonic anhydrase II. This immunocytochemical study supports previous morphological findings in differences in differentiation between the cells of tumours produced by high and low passage cells.
 ...
PMID:Immunocytochemical characterization of the A15 A5 transplantable brain tumour model in vivo. 287 14

The interaction of tumour cells with basement membrane components is thought to be important in influencing their invasive and metastatic properties. This paper describes the effect of laminin on the attachment of radiolabelled glioma and B16 murine melanoma cells to tissue culture plastic and type IV collagen. With the exception of the non-metastatic B16 F1 variant, laminin (and fibronectin) stimulated cell attachment to tissue culture plastic. Although laminin stimulated the attachment of the B16 BL6 metastatic variant to type IV collagen, it consistently inhibited the attachment of the glioma cells under the same conditions. Laminin appeared to exert its effect by adsorption to the collagen and was not cytotoxic to the glioma cells. In contrast, fibronectin had very little effect on cell attachment to type IV collagen. One of the most unusual features of glioma is the rarity of metastasis to extraneural sites. However, the effect of laminin observed here may not be the only factor involved in the metastatic inefficiency of this tumour type.
 ...
PMID:Effects of laminin on the attachment of glioma cells to type IV collagen. 292 51

Two continuous human glioma-derived cell lines, UC-11MG and UC-302MG were established in our laboratory. Both cell lines persistently showed cytologic features similar to those of their respective original tumors. UC-11MG expressed glial fibrillary acidic protein (GFAP) and S-100 protein. The cell lines were negative for factor VIII related antigen (FVIII/RAg) and positive for fibronectin and neuronal specific enolase (NSE). Electron microscopic studies of UC-11MG revealed intermediate filament; filopodia and pinocytic vesicles were present in both lines. Dibutyryl cAMP (dB-cAMP) caused inhibition of growth and marked shift in the morphology of UC-302MG toward spindle cells. The cytologic appearance of UC-11MG treated with dB-cAMP was altered less, but cells showed a stronger GFAP expression, with 'cable' formation. Doubling time was 41.0 +/- 6.4 hours for UC-11MG and 43.7 +/- 6.6 hours for UC-302MG. The karyotypes of both cell lines were aneuploid with chromosomal derangement and markers characteristic for each line.
 ...
PMID:Continuous human glioma-derived cell lines UC-11MG and UC-302MG. Morphologic, immunocytochemical and chromosomal characterization. 300 88

Explants of cells of a human glioma were evaluated with the nuclear fluorochrome 4',6-diamidino-2-phenylindole, by phase-contrast illumination, and by Giemsa staining correlated with double immunofluorescence for glial fibrillary acidic protein (GFAP) and fibronectin (FN). FN-positive (FN+) cells lacked GFAP detectable by immunofluorescence. Their mean nuclear-to-cytoplasmic ratio was large (0.192). Actual mean areas of nuclei (1,252 microns2) and cytoplasm (8,376 microns2) of FN+ cells compared with mean areas of fibroblasts suggested that the high nuclear-to-cytoplasmic ratio of FN+ cells was due to their microscopically evident reduced cytoplasmic spreading rather than to larger nuclei. Some FN+ cells showed marked variation in nuclear and nucleolar size and shape. Others had abnormal mitoses or hyperchromatic nuclei. GFAP-positive (GFAP+) cells lacked FN detectable by immunofluorescence. GFAP+ cells were smaller and less round than FN+ cells. Their usual location was growing on a layer of FN+ cells. The mean nuclear-to-cytoplasmic ratio (0.245) of GFAP+ cells was the highest in the study, surpassing the ratio of the continuous glioma line LM (0.176). Mean areas of nuclei (289 microns2) and of cytoplasm (1,350 microns2) of GFAP+ cells suggested that their high nuclear-to-cytoplasmic ratio was due to their microscopically evident reduced cytoplasmic spreading. Reduced spreading was associated with extension of long, thin cytoplasmic processes. The majority of GFAP+ cells showed marked cytoplasmic basophilia, nuclear hyperchromasia, and clumped chromatin. Features observed in both FN+ and GFAP+ cells from this high-grade astrocytoma are features associated with malignant transformation in more thoroughly studied tumor systems.
 ...
PMID:Products of cells cultured from gliomas. V. Cytology and morphometry of two cell types cultured from glioma. 302 5


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