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)

Using a model of doxorubicin-resistant rat glioblastoma cells, we have studied the relationship between the reversal of multi-drug resistance by verapamil and calcium fluxes into the cells. Although it is known to be a voltage-dependent calcium channel blocker, verapamil exerted no effect on calcium entry into the cells. In the absence of calcium in the medium, drug resistance was not affected and verapamil was still active. It was possible to modify calcium fluxes into the cells by using manganese ions (decreasing calcium uptake) or the calcium ionophore A23187 (increasing calcium uptake). These agents had only a marginal effect on the expression of drug resistance by the cells and did not prevent the action of verapamil on its reversal.
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PMID:The reversal of doxorubicin resistance by verapamil is not due to an effect on calcium channels. 244 53

Human glioblastoma cells secrete a peptide termed glioblastoma-derived T cell suppressor factor (G-TsF) which inhibits T cell activation. Recently, purification and cloning of G-TsF revealed that G-TsF is identical to transforming growth factor-beta 2. As shown here, G-TsF suppresses the growth of an ovalbumin-specific mouse T helper cell clone (OVA-7T) independently of the stimulus used being either (a) antigen in the presence of antigen-presenting cells, or (b) interleukin 2 (IL2) or (c) phorbol ester and calcium ionophore. Furthermore, in the presence of antibodies against IL2 receptors, G-TsF was able to suppress the residual proliferation still observed when OVA-7T were stimulated with phorbol ester/ionophore. G-TsF failed to inhibit the release of IL3 from OVA-7T activated with IL2. Taken together, the data provide evidence that G-TsF does not directly interfere with interactions of IL2 with its receptor but rather inhibits T cell activation by interfering with an as yet unidentified pathway used by both IL2 and phorbol ester/ionophore. When analyzing different monokines and lymphokines for its effect on G-TsF-induced suppression of T cell growth the only factor found to partially neutralize the effect of G-TsF was tumor necrosis factor-alpha.
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PMID:The glioblastoma-derived T cell suppressor factor/transforming growth factor-beta 2 inhibits T cell growth without affecting the interaction of interleukin 2 with its receptor. 245 45

Bombesin/gastrin-releasing peptide receptors were characterized in human glioblastoma cell lines. [125I]Gastrin-releasing peptide or ([125I]Tyr4)bombesin bound with high affinity to these cell lines. Binding to cell line U-118 was time dependent, reversible, and specific. ([125I]Tyr4)Bombesin bound with high affinity (Kd = 1.6 nM) to a single class of sites (Bmax = 30,000/cell). The C-terminal of bombesin- or gastrin-releasing peptide was essential for high-affinity binding. Bombesin- or gastrin-releasing peptide elevated the cytosolic Ca2+ levels in a dose-dependent manner. Because gastrin-releasing peptide, but not gastrin-releasing peptide, increased the cytosolic Ca2+ levels, the C-terminal but not the N-terminal of GRP is essential for biological activity. These data indicate that biologically active bombesin receptors are present in human glioblastoma cell lines.
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PMID:Human glioblastoma cell lines have neuropeptide receptors for bombesin/gastrin-releasing peptide. 256 55

The effects of 2 specific calcium channel blockers, verapamil and nimodipine, on the proliferation of human glioma tumour cells were investigated in vitro. Tumour tissues for primary cell cultures were obtained bioptically from 3 patients with the histopathological diagnosis of glioblastoma. The [3H]-thymidine incorporation into glioma tumour cells DNA was used as a sensitive index of the cell proliferation. It was found that verapamil (10(-4)-10(-5) M) and nimodipine (10(-4)-10(-6) M) significantly inhibited the [3H]-thymidine uptake in a dose-related manner. The inhibitory effect of both calcium channel antagonists was reversed by simultaneous addition of calcium chloride (5 x 10(-3) M). These results indicate that verapamil and nimodipine may exert an antiproliferative effect on glioma cells growth acting through a blockade of specific voltage-dependent calcium channels.
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PMID:Inhibitory effect of calcium channel blockers on proliferation of human glioma cells in vitro. 271 24

The authors investigated the immunohistochemical localization of S-100 protein in normal human brain and glioblastoma tissues by the peroxidase anti-peroxidase method of Sternberger. In normal human brain the positive immunoperoxidase reaction for S-100 protein was observed in astrocytes, oligodendrocytes, ependymal cells, Bergmann's glial cells and epithelial cells of choroid plexus. No positive staining was revealed in any cortical neurons. Immunoelectron-microscopically, the electron dense positive reaction for S-100 protein was seen throughout the cytoplasm, nucleoplasm and cell processes of astrocyte as well as oligodendrocyte. The positive reaction for S-100 protein was demonstrated occasionally in association with cytoplasmic membrane or the membrane constituting cell organelles. We suspect that this observation indicates the existence of membrane-bound form of S-100 protein. In glioblastoma cells, the positive reaction for S-100 protein was relatively weak in intensity as compared with astrocytes, and the degree of positive staining varied from cell to cell. Subcellular localization of S-100 protein in glioblastoma seemed to be essentially similar to that of normal astrocyte. There are some recent reports concerning immunohistochemical localization of alpha and beta subunits of S-100 protein. As compared with these reports, the present immunohistochemical results indicate that the rabbit anti-S-100 antibody embloyed in the present study is mainly against beta subunit of S-100 protein. Although there have been many reports concerning immunohistochemical localization of S-100 protein, the biological role of S-100 protein is still speculative. Some hypotheses are advocated in connection with the possible biological role of S-100 protein. For example, the modulation of synaptic transmission by S-100 protein, the participation of S-100 protein in hormonal secretion and in transport of cations through lipid membrane, the activation of protein kinase and the promotion of disassembly of microtubules by S-100 protein are postulated. It is hard to assume the biological role of S-100 protein based on the immunohistochemical results alone. The present study clearly indicates that S-100 protein exists widely in the cytoplasm, nucleoplasm, cytoplasmic membrane, outer membranes of cell organelles and cell processes of glial cells as well as glioblastoma cells. From these results we assume that S-100 protein plays an important role of intracellular transport of cations as one of the calcium binding proteins.
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PMID:[Immunohistochemical study of S-100 protein in the normal human brain and glioblastoma]. 391 99

Intracellular recordings were performed in a primary astrocyte culture from rat brain and in a human glioblastoma cell line, 138 MG. The technique proved insufficient to verify the heterogeneous composition of the primary astrocyte culture, since this study shows most cells present in the culture to have similar resting membrane potential, membrane impedance, membrane potential/impedance relationship and K+-sensitivity. With the exception of macrophages, identified by their response to externally applied yeast particles, the results do not allow the identification of different cells that are known to be present. The membrane potential of the primary astrocyte was -68 +/- 14 mV, and the membrane potential of the 138 MG cells -37 +/- 15 mV. The membrane potential of cells in the primary culture have a K+-sensitivity resembling that of astrocytes in situ, whereas the K+-sensitivity of 138 MG more resemble that of a dedifferentiated cell. A reduction of 0.95 mm Ca2+ to o mM depolarizes the astrocyte with 9.6 mV and hyperpolarizes the glioma cell 2.6 mV.
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PMID:Some observations made by intracellular recordings in a primary astrocyte culture and a glioblastoma '138 MG'. 396 87

Twenty-five neonatal beagles were used for this study. Gliosarcoma was injected into the cerebral hemisphere of 7 neonatal beagles (Group I). These animals were then treated by boron neutron capture therapy. The response of the tumor to therapy was evaluated by serial CT scans and 3 times magnification of cerebral angiography. The animals were sacrificed at varying post-therapy periods for histological study. Fifteen neonatal beagles implanted gliosarcoma without therapy (Group II) and 3 normal controls without tumor (Group III) were subjected to the same follow-up studies. (Results) (1) Neonatal beagles with implanted tumor showed moderate degree of ventricular dilatation within a short period. The finding of communicating hydrocephalus was interpreted as initial growth of tumor. (2) Animals after therapy had variable cavitation in the hemisphere that had contained calcium deposit on CT. Moderate dilatation of the lateral ventricle was present without any significant midline shift and there was an area of porencephaly extending out from the right lateral ventricle on CT (Fig. 1, Case 2). Cerebral angiography demonstrated hydrocephalus with an avascular region in the right cerebral hemisphere, compatible with the previously described porencephalic cyst (Fig. 2, Case 2). (3) Three cases out of 7 showed neurological symptoms after tumor implantation (Cases 3, 5 and 6). Carotid angiography showed large temporal lobe tumor with some tumor stain and also some involvement of the right frontal lobe after therapy (Fig. 7, Case 3). In postmortem examination, there was tumor seen coating the right lateral ventricle as well as the left temporal horn. The right cerebral hemisphere was slightly smaller than the left. The left lateral ventricle was remarkably enlarged (Fig. 9). (4) Four out of 7 treated animals with injected gliosarcoma showed no evidence of tumor at postmortem examination. CT demonstrated moderate dilatation of the lateral ventricle without any significant midline shift, an area of porencephaly and definite decrease in size of the right cerebral hemisphere and calvarium (Fig. 4). (5) Fifteen neonatal beagles implanted gliosarcoma without therapy (Group II) developed symptomatic and died within two weeks. (6) Control animals showed no ventricular dilatation or other abnormalities. (7) Microscopic examinations showed no similarities between implanted gliosarcoma and human glioblastoma. (Conclusion) Serial CT scans and magnification cerebral angiography in this experimental model appear extremely helpful in following the effects of therapy and important tool for the evaluation of a tumor growth or regression.
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PMID:[Neuroradiological Evaluation of an experimentally implanted tumor into cerebral hemisphere of neonatal beagles (author's transl)]. 709 78

Just as the average value of the attenuation coefficient can be represented by the brightness of the pixel, the energy structure of the attenuation coefficient determines its hue. This can be measured by filtering the x-ray beam with W, Pb, and Sn at 100, 120, adn 140 kVp, respectively. The color differences seen in (a) CT images of phantom materials such as iodine and calcium, (b) brain specimens containing hemorrhage, meningioma, glioblastoma, or metastases, and (c) preliminary in vivo head and body scans represent variations in chemical composition across the tissue section. Measurements show that energy-selective filtration increases the separation between effective energies while reducing the dose for the same number of transmitted x rays.
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PMID:Increased tissue differentiation using color display of multiple-energy CT scans. 735 28

Interleukin-11 (IL-11) is a pleiotropic cytokine with important effects on hematopoietic and other cells. IL-11 was originally described as a product of stromal cell lines and fibroblasts. Using RT-PCR, Northern blotting, and ELISA we demonstrated that the human U373 and U87 glioblastoma cell lines expressed IL-11 and its encoding mRNA when stimulated with IL-1 beta, phorbol ester, and calcium ionophore. The neuroblastoma cell line SH-SY5Y did not express IL-11 mRNA in response to these agents. Cerebral expression of IL-11 by glial cells is important because IL-11 has been shown to have effects on neuronal electrophysiology, has overlapping functions with the neuroactive cytokine interleukin-6, and is part of the gp130-associated neuropoietic family of cytokines.
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PMID:Expression of interleukin-11 and its encoding mRNA by glioblastoma cells. 750 Dec 71

We examined levels of mRNA and protein for N-cadherin, the predominant cadherin in neural tissues, and mRNA levels for the cadherin-associated protein, alpha-catenin, in a series of gliomas and in glioblastoma cell lines. mRNA levels for N-cadherin and alpha-catenin were significantly higher in glioblastomas than in low-grade astrocytomas or normal brain, while the levels of intact N-cadherin protein were similar in glioblastomas, low-grade astrocytomas and brain. In addition, there was no consistent relationship between invasiveness and expression of N-cadherin and alpha-catenin in highly invasive vs minimally invasive tumours within the same histopathological grade. To assess further the relationship between cadherin expression and neural tumour invasion, we measured N-cadherin expression, calcium-dependent cell adhesion and motility of several glioblastoma cell lines. While all N-cadherin-expressing lines were adhesive, no correlation was seen between the level of N-cadherin expression and cell motility. Together, these findings imply that, in contrast to the role played by E-cadherin in carcinomas, N-cadherin does not restrict the invasion of glioblastomas.
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PMID:Expression of N-cadherin and alpha-catenin in astrocytomas and glioblastomas. 766 72


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