Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0017636 (glioblastoma)
 18,345 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This report describes the preparation of polylysine-diethylene triamine pentaacetic acid (DTPA)-metal ion complexes and of iodinated polylysine derivatives and the preferential binding of these polymers to glioblastomas in culture. Synthetic polylysines (DP88 and DP299) were modified covalently either with the chelator DTPA or with 125I-Bolton Hunter reagent. The polylysine (DP88) was modified initially with fluorescein to permit fluorescence cytological studies and quantitative measurements of polylysine concentrations. The polylysines contained an average of one DTPA per 16 lysyl moieties. The polylysine-DTPA derivatives were then modified with a mixture of 153Gd and stable Gd. A copolymer (DP120) of lysine and tyrosine (4:1) was modified with 125I using chloramine T as catalyst. C6 (rat) and U87 MG (human) glioblastoma cells, in culture, bound six to seven times more polylysine-DTPA-Gd than endothelial cells from either aorta or brain. Each of the tumor cell types bound 10(8) molecules of the modified polylysine per cell when 2.5 x 10(5) cells were reacted with 50 micrograms or greater of the polylysine-DTPA-nuclide complex. The higher molecular weight polylysines delivered more radionuclide to the cells in culture. Although the tumor cells bound more [125I]polylysine and [125I]poly(lysine HBr,tyrosine) than they bound polylysyl-DTPA-Gd, the endothelial cells and the plastic culture dish also bound more of the iodinated polymers. The stoichiometry of polylysine bound per cell suggests that the sialic acid moieties on the cell surface are the primary binding sites for polylysine derivatives. Fluorescence microscopy studies revealed that the fluorescein polylysine (DP88) and the fluorescein polylysine-DTPA nuclide complex bound the tumor cells primarily at branch points along the neuritic processes, at the edge of the perikaryon and at the terminal regions of the outgrowth process. The polylysyl-DTPA-Gd can be used, with magnetic resonance imaging, to provide measurable contrast of the margin between C6 glioblastomas and normal brain in vivo in Wistar Furth rats.
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PMID:Preferential binding of radiolabeled poly-L-lysines to C6 and U87 MG glioblastomas compared with endothelial cells in vitro. 280 85

Differentiated oligodendrocytes and central nervous system (CNS) myelin are nonpermissive substrates for neurite growth and for cell attachment and spreading. This property is due to the presence of membrane-bound inhibitory proteins of 35 and 250 kD and is specifically neutralized by monoclonal antibody IN-1 (Caroni, P., and M. E. Schwab. 1988. Neuron. 1:85-96). Using rat optic nerve explants, CNS frozen sections, cultured oligodendrocytes or CNS myelin, we show here that highly invasive CNS tumor line (C6 glioblastoma) was not inhibited by these myelin-associated inhibitory components. Lack of inhibition was due to a specific mechanism as the metalloenzyme blocker 1,10-phenanthroline and two synthetic dipeptides containing metalloprotease-blocking sequences (gly-phe, tyr-tyr) specifically impaired C6 cell spreading on CNS myelin. In the presence of these inhibitors, C6 cells were affected by the IN-1-sensitive inhibitors in the same manner as control cells, e.g., 3T3 fibroblasts or B16 melanomas. Specific blockers of the serine, cysteine, and aspartyl protease classes had no effect. C6 cell spreading on inhibitor-free substrates such as CNS gray matter, peripheral nervous system myelin, glass, or poly-D-lysine was not sensitive to 1,10-phenanthroline. The nonpermissive substrate properties of CNS myelin were strongly reduced by incubation with a plasma membrane fraction prepared from C6 cells. This reduction was sensitive to the same inhibitors of metalloproteases. In our in vitro model for CNS white matter invasion, cell infiltration of optic nerve explants, which occurred with C6 cells but not with 3T3 fibroblasts or B16 melanomas, was impaired by the presence of the metalloprotease blockers. These results suggest that C6 cell infiltrative behavior in CNS white matter in vitro occurs by means of a metalloproteolytic activity, which probably acts on the myelin-associated inhibitory substrates.
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PMID:Glioblastoma infiltration into central nervous system tissue in vitro: involvement of a metalloprotease. 319 88

Human cytomegalovirus (HCMV) glycoprotein B (gB) promotes virion entry into cells by fusing the virion envelope with the cellular membrane. We recently reported that UB cells (U373 glioblastoma cells constructed to produce HCMV gB constitutively) form multinucleate syncytia that are dependent on the density of gB in the plasma membrane. In this report, we describe the properties of a clonal cell line, UB31-B3, that expressed a spontaneously mutated form of gB which lacked the fusion-inducing function of the wild-type molecule, and three UB cell lines that were constructed to investigate the effect of specific mutations in gB on syncytium formation. Flow cytometry analysis with a pool of monoclonal antibodies (mAbs) showed that the UB cells contained a high density of gB, which was associated with the cell surface. Immune precipitation experiments with UB31-B3 cells showed that the mutant gB reacted with all of the mAbs to the ectodomain of gB but with none of those to the cytoplasmic carboxy terminus, and that it was 35 kDa smaller than wild-type gB. Nucleotide sequence analysis showed that a termination codon had been introduced after amino acid lysine at position 669 in the ectodomain of UB31-B3 gB, generating a truncated glycoprotein. UB31-B3 gB was not secreted into the medium and was stably anchored in the plasma membrane, which suggested that a hydrophobic stretch of amino acids from 629 to 652 in the ectodomain may serve as a membrane anchor for this truncated form. Analysis of the UB cell lines expressing deleted forms of gB showed that deletion of all or part of the cytoplasmic and transmembrane domains reduced or abolished syncytium formation. In contrast, deletion of a major neutralizing region in the ectodomain of gB did not alter syncytium formation. Results of these studies indicate that different regions of the gB molecule participate in syncytium formation.
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PMID:Mutated forms of human cytomegalovirus glycoprotein B are impaired in inducing syncytium formation. 777 90

Astrocytoma (WHO grade II, III), glioblastoma, malignant melanoma, and normal glial cell cultures, established from biopsies, were investigated by 1H MRS. At a 1H resonance frequency of 500 MHz (11.75 T) a high spectral resolution was achieved in 1D 1H spectra; in conjunction with 2D shift-correlated (COSY) MRS, resonances of alanine, aspartate, choline, creatine, glutamate, glutamine, hypotaurine, myo-inositol, phosphocreatine, phosphoryl-ethanolamine, phosphoryl-choline, lactate, lysine, N-acetylaspartate, taurine, threonine and valine could be identified. T1 relaxation times for the most prominent compounds are presented. T1 values of lactate ranged between 450 ms and 850 ms. The intensity of the lactate signal revealed differences between individual spectra, but exhibited no correlation between different tumor specimens or degree of malignancy. It was shown that the lactate signal at 1.3 ppm is covered by peaks arising from threonine and fatty acids. The choline signal level varied among spectra of different tumors, among tumors with similar degree of malignancy, and within the same tumor. Further preliminary differences due to aspartate, inositol and glutamine/glutamate were found in 1D and 2D COSY spectra between normal glial cells as well as different tumors. These results indicate that some differences observed in in vivo spectra may be attributable to secondary macroscopic structural changes (hypoxia, necrosis) and not to tumor inherent characteristics. Further correlation between in vivo and in vitro spectroscopy is therefore required.
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PMID:High-resolution one- and two-dimensional 1H MRS of human brain tumor and normal glial cells. 808 Jul 12

Glioblastoma multiforme is a highly invasive primary brain tumor with a disappointingly high local recurrence rate and mortality despite intensive multimodality treatment programs. Therefore, new agents that are capable of inhibiting the infiltration of normal brain parenchyma by glioblastoma cells are urgently needed. Here, we show that the novel quinazoline derivatives 4-(4'-hydroxylphenyl)-amino-6,7-dimethoxyquinazoline (WHI-P131) and 4-(3'-bromo-4'hydroxylphenyl)-amino-6,7-dimethoxyquinazoline (WHI-P154) are potent inhibitors of glioblastoma cell adhesion and migration. Specifically, both compounds inhibited at micromolar concentrations: (a) integrin-mediated glioblastoma cell adhesion to the extracellular matrix proteins laminin, type IV collagen, and fibronectin; (b) integrin-independent epidermal growth factor-induced adhesion of glioblastoma cells to poly-L-lysine-coated tissue culture plates; (c) fetal bovine serum-induced polymerization of actin and actin stress fiber formation as well epidermal growth factor-stimulated formation of focal adhesion plaques in serum-starved glioblastoma cells; and most importantly, (d) glioblastoma cell migration in in vitro assays of tumor cell invasiveness using tumor cell spheroids and/or Matrigel-coated Boyden chambers. Further preclinical development of WHI-P131 and WHI-P154 may provide the basis for the design of more effective adjuvant chemotherapy programs for glioblastoma multiforme.
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PMID:Inhibition of human glioblastoma cell adhesion and invasion by 4-(4'-hydroxylphenyl)-amino-6,7-dimethoxyquinazoline (WHI-P131) and 4-(3'-bromo-4'-hydroxylphenyl)-amino-6,7-dimethoxyquinazoline (WHI-P154). 979 79

A trypsin-like serine proteinase was purified from the incubation medium of rat brain slices by gelatin zymography. The purification consisted of ammonium sulfate precipitation, benzamidine-Sepharose 6B affinity chromatography, and carboxymethyl-cellulose and gel filtration chromatographies. The gelatinolytic activity, identified at 22 kDa (P22) by sodium dodecyl sulfate-polyacrylamide gel electrophoresis under nonreducing conditions, was eluted as one active peak throughout the purification, and the final preparation gave a single protein peak on reverse-phase HPLC. Diisopropyl fluorophosphate, benzamidine, p-toluenesulfonyl-L-lysine chloromethyl ketone, and aprotinin completely inhibited the activity of P22, whereas phenanthroline, p-toluene-sulfonyl-L-phenylalanine chloromethyl ketone, and elastinal did not. P22 efficiently digested the extracellular matrix proteins laminin and type IV collagen. P22 produced an increase in intracellular Ca2+ concentration in A172 glioblastoma, which was desensitized through prior stimulation with protease-activated receptor-2 agonist peptide SLIGKV, indicating that P22 can stimulate protease-activated receptor-2. Rat brain penetration injury induced gelatinolytic activity in the lesioned area whose molecular size was consistent with that of P22. These results indicated that on incubation of rat brain slices, a trypsin-like serine proteinase was secreted into the medium that was capable of digesting extracellular matrix and stimulating protease-activated receptor-2. It is suggested that the gelatinolytic activity induced by brain injury might be that of P22.
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PMID:Purification and characterization of a trypsin-like serine proteinase from rat brain slices that degrades laminin and type IV collagen and stimulates protease-activated receptor-2. 1073 32

Research studies suggest that tumor-related angiogenesis contributes to the phenotype of malignant gliomas. We assessed the effect of local delivery of the angiogenesis inhibitor endostatin on human glioma cell line (U-87MG) xenografts. Baby hamster kidney (BHK) cells were stably transfected with a human endostatin (hES) expression vector and were encapsulated in alginate-poly L-lysine (PLL) microcapsules for long-term delivery of hES. The release of biologically active endostatin was confirmed using assays of bovine capillary endothelial (BCE) proliferation and of tube formation. Human endostatin released from the microcapsules brought about a 67. 2% inhibition of BCE proliferation. Furthermore, secreted hES was able to inhibit tube formation in KDR/PAE cells (porcine aortic endothelial cells stably transfected with KDR, a tyrosine kinase) treated with conditioned U-87MG medium. A single local injection of encapsulated endostatin-secreting cells in a nude mouse model resulted in a 72.3% reduction in subcutaneous U87 xenografts' weight 21 days post treatment. This inhibition was achieved by only 150.8 ng/ml human endostatin secreted from 2 x 10(5) encapsulated cells. Encapsulated endostatin-secreting cells are effective for the treatment of human glioblastoma xenografts. Continuous local delivery of endostatin may offer an effective therapeutic approach to the treatment of a variety of tumor types.
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PMID:Continuous release of endostatin from microencapsulated engineered cells for tumor therapy. 1113 44

Little is known about the genetic and molecular events leading to the early stages of human astrocytoma formation. To examine this issue, we analyzed the significance of sequential accumulation of two somatic point mutations (R267W and E258D) in the TP53 gene during the initiation of astrocytoma in a patient born with a single germ-line p53 point mutation (R283H). We adapted a p53 transcriptional assay in yeast to establish the temporal occurrence and allelic distribution of the p53 mutations present in the patient and characterized these mutations through functional assays and structural modeling. Our results show that the first somatic mutation occurred at codon 267 on the p53 allele harboring the germ-line mutation R283H, whereas the second somatic mutation occurred in the remaining wild-type (wt) allele at codon 258. These two mutations induced the formation of tumor cells with the genotype p53(267W+283H/258D), which comprised 70% of the cells in the primary WHO grade II astrocytoma. Another 8% of cells within the tumor had the partially mutated genotype p53(267W+283H/WT) and represented the remnants of a clinically undetectable intermediate stage of astrocytic neoplastic transformation. The remaining 22% of cells had the constitutive p53(283H/WT) genotype and likely consisted of nontumor cells. Functional analysis of the p53 alleles present in the patient's tumor indicated that the germ-line p53(R283H) could transactivate the CDKN1A((p21, WAF1, cip1, SDI1)) but not the BAX gene and retained the ability to induce growth arrest of human glioblastoma cells. The p53(R267W+R283H) and p53(E258D) were incapable of transactivating either promoter or inducing growth arrest. Modeling of p53 interaction with DNA suggests that R283H mutation may weaken the sequence-specific interaction of p53 lysine 120 with the BAX gene but not the CDKN1A p53-responsive elements. Taken together, these results have characterized, for the first time, the genetic events defining a clinically undetectable precursor lesion leading to a grade II astrocytoma. They also suggest that astrocytoma initiation in this patient resulted from monoclonal evolution driven by a sequential loss of proapoptotic and growth arrest functions of p53.
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PMID:Initiation of human astrocytoma by clonal evolution of cells with progressive loss of p53 functions in a patient with a 283H TP53 germ-line mutation: evidence for a precursor lesion. 1201 70

As little is known about the role of cadherin-mediated cell-cell adhesion in astrocytes and its alteration in migrating and invasive glioblastomas, we investigated its molecular composition and organisation in primary cultured astrocytes and the T98G and U373MG glioblastoma cell lines. Biochemical and morphological analysis indicated that all three cell types express all of the structural components of the adhesion system, including the LIN-7 PDZ protein, a novel component involved in the organisation of the junctional domain in epithelia and neurons. However, only the astrocytes and T98G cells generated and maintained mature adhesive junctional domains to which LIN-7 was recruited. Alterations in the junctional domain of U373MG cells were associated with higher motility in a poly-L-lysine migration assay. When the T98G cells were cultured on Matrigel matrix, they acquired invasive properties but, despite unchanged cadherin adhesion system protein levels, the invasive T98G cell-cell contacts failed to accumulate LIN-7 and failed to mature. These results identify the LIN-7 PDZ protein as a marker of cell adhesion maturity and cell invasion and indicate that instability and disorganisation of cadherin-mediated junctions rather than reduced expression of cadherin-catenin system components are required to promote migration and invasiveness in glioblastoma cell lines.
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PMID:Invasive behaviour of glioblastoma cell lines is associated with altered organisation of the cadherin-catenin adhesion system. 1214 Feb 64

We previously showed that enhanced expression of MMP-9, an endopeptidase that digests basement-membrane type IV collagen, is related to tumor progression in vitro and in vivo; antisense-MMP-9 stably transfected clones were less invasive than untransfected parental cells and did not form tumors in nude mice. In this study, we examined the role of ERK-1 in the regulation of MMP-9 production and the invasive behavior of the human glioblastoma cell line SNB19, in which ERK1 is constitutively activated. SNB19 cells were stably transfected with mt-ERK, a vector encoding ERK-1 cDNA in which the conserved lysine at codon 71 was changed to arginine, thus impairing the catalytic efficiency of this enzyme. Gelatin zymography showed reduced levels of MMP-9 in the mt-ERK-transfected cell lines relative to those in vector-transfected and parental control cells. Reductions in MMP-9 protein mRNA levels were also detected in the mt-ERK-transfected cells by Western and Northern blotting. The mt-ERK-transfected cells were much less invasive than parental or vector control cells in a Matrigel invasion assay and in a spheroid coculture assay. Thus an ERK-dependent signaling pathway seems to regulate MMP-9 mediated glioma invasion in SNB19 cells; interfering with this pathway could be developed into a therapeutic approach, which aims at a reduction of cancer cell invasion.
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PMID:Downregulation of MMP-9 in ERK-mutated stable transfectants inhibits glioma invasion in vitro. 1216 59


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