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)

5'-Nucleotidase has been purified from rat glioblastoma cells (Rugli cells). The enzyme has been solubilized from plasma membranes by using Triton X-100 and CHAPS. Two affinity chromatographies on concanavalin A and 5'-AMP-Sepharose render the purified enzyme with a high specific activity (76.36 mumol AMP.min-1.mg-1). The purified enzyme gives a single polypeptide band on SDS-PAGE with an apparent molecular mass of 74 kDa. Active forms with an apparent molecular mass of 135 kDa and 268 kDa are observed when the purified enzyme is analyzed by gel filtration in the presence of either 0.6% sodium deoxycholate or 0.1% Triton X-100, respectively. The purified 5'-nucleotidase presents optimum activity at pH 7.8-8.1 either in the presence or in the absence of Mg2+. A linear Arrhenius plot is observed in the 25-46 degrees C temperature range and an activation energy of 33.7 KJ/mol is calculated. The enzyme is inhibited by EDTA; the activity is partially restored by different divalent cations as Zn2+, Mn2+, and Co2+. The hydrolysis of nucleosides 5'-monophosphate shows Michaelis kinetic. The enzyme is inhibited by nucleosides di- and triphosphate. 5'-Nucleotidase is a glycoprotein, being its activity inhibited at different extent by various lectins.
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PMID:Isolation and characterization of the ecto-5'-nucleotidase from a rat glioblastoma cell line. 148 Jan 62

A large-animal model was developed to facilitate the noninvasive investigation of the effect on the human glioma-derived D-54 MG (glioblastoma multiforme) continuous cell line of a variety of therapeutic regimens. Twenty random-bred male cats were inoculated intracerebrally with 1 x 10(7) D-54 MG tumor cells after being initiated on one of three preparatory regimens of cyclosporin A p.o. Reproducible success of D-54 MG xenotransplantation (100%, 6 of 6 cats) was achieved only after pretreatment with 120 mg cyclosporin A p.o. (24-30 mg/kg) daily for greater than or equal to 10 days prior to tumor implantation. High-performance liquid chromatography-derived whole blood cyclosporin A 12-h trough levels of greater than or equal to 640 ng/ml were seen in successful implants. Lesions ranging from 2 to 20 mm in diameter were seen in cats sacrificed 27-44 days after implantation with no growth seen in control animals. Histopathological examination revealed the tumors to be well-circumscribed anaplastic intracerebral tumors with some invasion into surrounding host parenchyma. Perivascular lymphocytic cuffing was observed, but intratumoral lymphocytic infiltration was minimal. Gadolinium-EDTA-enhanced nuclear magnetic resonance imaging provided accurate tumor localization in T1-weighted images (TE 26 ms; TR 600 ms). Biochemical tests of kidney, liver, and hematological function were within normal limits, although 10% (2 of 20) of the animals developed gingival hyperplasia, and 5% (1 of 20) developed intussusception. The reproducible growth of the D-54 MG human glioblastoma cell line in a large-animal model eliminates many of the limitations associated with the standard nude mouse/rat model, thereby providing a novel test bed for a variety of imaging modalities as well as for drug immunoconjugate localization and toxicity studies.
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PMID:Development of a large-animal human brain tumor xenograft model in immunosuppressed cats. 201 4

The effects of chelation of divalent cations in the interaction of platelets and tumor cells has been studied in a homologous human system using human platelet-rich plasma and two tumor cell lines of human origin: SKNMC (neuroblastoma) cells, which cause platelet aggregation by an adenosine diphosphate-dependent mechanism, and U87MG (glioblastoma) cells, which function by a thrombin-dependent mechanism. When added at zero time, citrate 14 mmol/L completely abolished aggregation in heparinized (5 U/ml) platelet-rich plasma by either cell line, but the degree of inhibition was reduced by later addition of the chelating agent. Calcium citrate 8 mmol/L reduced by only 10%, indicating that citrate anion was not responsible for the inhibition. Addition of Ca++ or Mg++ alone or in combination at concentrations up to 1.5 mmol/L did not reverse the inhibition. Addition of higher concentrations of Ca++ (2 mmol/L) caused immediate clotting, whereas concentrations of Mg++ up to 6 mmol/L were without effect. Inhibition could be reversed by washing the platelets free of citrate and resuspending in heparinized platelet-rich plasma. Aggregation by either cell line was inhibited by EDTA and EGTA. In the Baumgartner perfusion apparatus, platelet interaction with subendothelium was increased about 50-fold in the presence of SKNMC cells, but this effect was also abolished after addition of citrate. After addition of U87MG cells to heparinized PRP, there was a 400-fold increase in platelet interaction with subendothelium, and complex thrombi containing red cells, white cells, and fibrin were formed. This stimulation was reduced to control levels by addition of citrate.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of divalent cations on the interaction of platelets with tumor cells: aggregation and perfusion studies with two homologous human systems. 400 24

The nature of the refractoriness of C6 glioblastoma cells to herpes simplex virus type I (HSV-I) infection has been studied. The cells were restricted in susceptibility to HSV-I since only a small proportion of the cells could be infected by HSV-I and the virus yield per cell was low. The susceptibility to infection was increased by treating the cells with trypsin-EDTA prior to infection. The cells so treated recovered resistance to the virus when incubated at 37 degrees C, their resistance being restored to the initial level in 2 days. This restoration was inhibited by addition of cycloheximide or puromycin. Trypsin-EDTA treatment of C6 cells increased the efficiency of adsorption of HSV-I and the formation of stable cell-virus complexes from which the virus could not be dissociated by heparin.
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PMID:Stimulation of herpes simplex type I infection of C6 cells by trypsin-EDTA. 624 84

Monoclonal antibodies ( MCAs ) have been derived from a fusion of P3-NS1/1-Ag 4-1 (NS1) myeloma cells and splenocytes immunized to human glioma cell line D-54 MG. MCAs 2F3 , 4C7 , and 5B7 were analyzed by cell surface radioimmunoassay (CS-RIA), quantitative absorption, indirect immunofluorescence, and peroxidase-anti-peroxidase (PAP) immunohistology of unfixed tissue samples. MCA 2F3 exhibits the most highly restricted pattern of reactivity we have observed, reacting only with 5/12 glioblastoma cell lines and 1/4 fetal skin lines by CS-RIA, and to 9/11 glioblastoma tissue samples by PAP and absorption analysis; this MCA is totally nonreactive with melanomas, neuroblastomas, meningiomas, and control non-central nervous system tumors, and to adult and fetal tissues including brain, thymus, spleen, liver, lung, heart, gut, skin, and muscle by PAP analysis. MCAs 4C7 and 5B7 demonstrate neuroectodermal tumor cross-reactivity profiles, reacting with either melanomas ( 5B7 ) or melanomas and neuroblastomas ( 4C7 ); both are reactive with fetal skin, brain, and thymus of less than or equal to 16 weeks of gestational age. Other than this latter fetal antigen reactivity, these MCAs share the same negative reactivity profile described above for MCA 2F3 . Data from experiments using control or 0.02% EDTA-treated confluent cell monolayers of D-54 MG as antibody absorbents showed that the antigens detected are present in the extracellular matrix material remaining following cell removal. The data presented here establish that these highly restrictive anti-human glioma cell line MCAs are expressed in primary human gliomas; that the markers defined are developmental in nature, in that they are expressed by human fetal tissue, but not by adult tissue; and that in conjunction with previously characterized specificities, these markers of antigenic heterogeneity will be valuable in model system studies of therapeutic response heterogeneity.
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PMID:Characterization of three restricted specificity monoclonal antibodies raised against the human glioma cell line D-54 MG. 637 21

Local invasive growth is one of the key features of primary malignant brain tumors accompanied by remodeling of the vasculature and destruction of normal brain tissue. Tissue invasiveness is an essential biological function used by a tumor to overcome the various barriers to its progression. The expression of metalloproteases has been shown to play a critical role in the invasive process in a number of tumors; however, their expression in human brain tumors has not been previously reported. In this study we showed metalloprotease activities at M(r) 240,000, 123,000, 92,000, 72,000, and 67,000 in brain tumor extracts. These enzyme activities were inhibited by EDTA, an inhibitor of metalloproteases. Significant increases in levels of protease bands at M(r) 92,000, 123,000, and 240,000 were observed in glioblastoma and metastatic lung tumors. Enzymatic inhibition and Western blotting with M(r) 92,000 type IV collagenase antibody confirmed the presence of M(r) 92,000 type IV collagenase in all samples. Quantitative analysis by densitometry showed 8-10-fold and 6-8-fold increases in M(r) 92,000 type IV collagenase activity in glioblastoma and metastatic lung carcinoma samples, respectively, when compared with normal brain, meningioma, astrocytoma, metastatic colon, and breast carcinoma samples. These findings provide evidence for elevated levels of metalloproteases in glioblastomas and suggest a therapeutic target for minimizing the invasive propensity of gliomas using protease inhibitors.
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PMID:Elevated levels of M(r) 92,000 type IV collagenase in human brain tumors. 848 4

Part of the neurodegenerative cascade in AIDS dementia may involve overexpression of matrix metalloproteinases (MMPs). Here, we examined the possible effect of HIV-1 gp41, which has been shown as a key determinant associated with pathogenesis of AIDS dementia, on the activity of MMPs using human neuronal and glial cell lines. Zymographic analysis revealed that treatment with the gp41 peptide (aa 583-599) for 24 h markedly elevated the activity of MMP with Mr 66 kDa in the cultured media of glioblastoma cell line T98G in a concentration-dependent manner as well as of neuroblastoma cell line SK-N-SH despite of lower magnitude of the activity. In contrast, the immediately adjacent gp41 peptide (aa 598-613) as well as the reverse peptide (aa 598-583) had a little effect. Recombinant gp41 protein containing extracellular domain also elicited a similar effect, although with a lesser extent. This 66 kDa MMP was confirmed as gelatinase A (MMP-2) based on the results of its activity dependent on Ca2+ and inhibited in the presence of 1,10-phenanthroline or EDTA, as well as its specific immunoreactivity on the Western blot. N-acetyl cysteine (NAC) downregulated this gp41 peptide-induced MMP-2 activity in T98G. The soluble form of amyloid precursor protein (sAPP), which is synthesized in the Escherichia coli system, also inhibited the MMP-2 activity in vitro. Taken together, these results implicate that high production of HIV-1 gp41 or its metabolites containing aa 583-599 within central nervous system (CNS) could result in the increased activity of MMP-2 and that the extracellular deficiency of reducing agent or decreased level of sAPP within CNS could exacerbate this gp41-induced MMP-2 activity.
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PMID:Increased activity of matrix metalloproteinase-2 in human glial and neuronal cell lines treated with HIV-1 gp41 peptides. 969 54

Differences on 5'-nucleotidase activity in intact Rugli and BCS-TC2 cells (rat glioblastoma and human colon adenocarcinoma cell lines, respectively) are not due to differences in the characteristics of the ectoenzyme. A membrane-bound 5'-nucleotidase from BCS-TC2 cells has been purified to homogeneity with a high specific activity (130 U/mg), yielding a single 72-kDa band on SDS-PAGE. It is a metalloenzyme and, after inhibition by EDTA, its activity can be partially restored by divalent cations. The hydrolysis of the nucleosides 5'-monophosphate used as substrate follows Michaelis-Menten kinetics; ADP and concanavalin A are competitive and non-competitive inhibitors of the AMPase activity, respectively. This ecto-5'-nucleotidase is a high-mannose glycoprotein; deglycosylation converts the 72-kDa into a 59-kDa protein with a concomitant activity loss. The enzyme purified from BCS-TC2 cells shows similar characteristics from that previously isolated from Rugli cells; differences between them are mainly due to glycosylation. Polyclonal antibodies against 5'-nucleotidase from BCS-TC2 cells also show cross-reactivity with the enzyme from Rugli cells. When the ectoenzyme activity is measured in cells in culture, Rugli cells present a higher activity than BCS-TC2 cells however, they express very low amounts of ecto-5'-nucleotidase. Our results also show a reduction in protein level and enzyme activity associated with a decrease in the differentiation degree and an increase in tumorigenicity of human colon adenocarcinoma BCS-TC2 sublines.
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PMID:Ecto-5'-nucleotidase from a human colon adenocarcinoma cell line. Correlation between enzyme activity and levels in intact cells. 978 49

Cytokines play important roles in the growth and growth arrest of cancer cells. IL-13 via an IL-4R alpha/IL-13R alpha 1 heterocomplex receptor inhibits the growth of renal cell carcinoma cells (RCC). However, it does not inhibit the growth of glioblastoma cells that express the IL-13R alpha 2 chain. In the present studies we investigated whether melanoma cells express IL-13R alpha 1 and IL-13R alpha 2 chains as well as whether they respond to IL-13. Membrane IL13R alpha 2 was co-expressed with IL-4R alpha and IL-13R alpha 1 chains in three of six tested melanoma cell lines. Furthermore, the IL-13R alpha 2 positive cell lines, release a soluble form of IL-13R alpha 2, specifically under IL-13 but not IL-4 stimulation. The release of soluble IL-13R alpha 2 was inhibited by various metalloproteinase inhibitors and EDTA inhibits the biological response to IL-13.
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PMID:Human melanoma cells release soluble and functional receptors. 1868 68

Glioblastoma multiforme (GBM) is the most common malignant and resistant tumor of the central nervous system in humans and new therapeutic strategies are urgently required. Recently, we have shown that the potential chemotherapeutic polyphenol xanthohumol (XH), isolated from Humulus Lupulus, induces apoptosis of human T98G glioblastoma cells by increasing reactive oxygen species and activating MAPK pathways. Then we have found, by western blotting and microscopic analysis, that XH up-regulates cytosolic levels of ANXA1 and induces translocation of the protein on the cell membrane of T98G cells in a time-dependent manner with significant effects observed after 24 h. On the basis of the above evidence, the aim of this work was to investigate the role of intracellular and cell membrane localized ANXA1 in GBM cells. RT-PCR analysis has shown that XH up-regulates mRNA levels of ANXA1 after 16 h treatment. To demonstrate the involvement of ANXA1 in apoptosis of GBM cells we down-regulated ANXA1 expression with small interfering RNA (siRNA) and then analysed apoptosis in the presence and absence of apoptotic stimuli. Importantly, apoptosis induced by XH was reduced in siRNA-ANXA1 transfected cells where western blot analysis shows a significant reduction of ANXA1 protein levels. To investigate the role of ANXA1 expression on the cell membrane of T98G cells as potential "eat-me" signal we studied phagocytosis of apoptotic cells by human macrophages. We incubated apoptotic T98G cells with human blood monocyte derived macrophages (M=). After co-incubation period we analysed the percentage of M= phagocytosing the apoptotic cells by cytofluorimetric FACS analysis and by confocal microscopy. Our results show that XH induces phagocytosis of apoptotic T98G cells by human M= in a concentration-effect manner, a processes that is dependent on caspase mediated apoptosis. ANXA1 acts as an "eat-me" signal on the cell membrane of T98G cells, and interestingly, apoptotic siRNA-ANXA1 transfected cells are not completely ingested by M=. These results were confirmed by incubating apoptotic cells with a neutralizing anti-ANXA1 antiboby and ANXA1 membrane depletion by EDTA washing. ANXA1 was also detected in supernatants of apoptotic cells and the incubation of enriched supernatants enhanced the percentage of phagocytosis by M=. These results demonstrated that ANXA1 is involved both in the apoptosis and phagocytosis of glioblastoma cells. This study shows a possible role of ANXA1 in maintenance of brain homeostasis and may lead to novel therapeutic approaches for neuro-inflammatory diseases and chemotherapy targets in the treatment of glioblastoma multiforme.
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PMID:The involvement of xanthohumol in the expression of annexin in human malignant glioblastoma cells. 2340 60


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