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Query: UMLS:C0017638 (glioma)
 30,880 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In vitro model systems in neurobiology are available to detect and help characterize various intercellular development signals. The presence of such active substances in conditioned medium (CM) from rat C6 glioma cells (2BD clone) was examined using the pheochromocytoma-derived clonal cell lines PC12 and PCG2. Conditioned medium from C6 monolayers induces neurite outgrowth in PC12 cells and extensive alteration in PCG2 cell morphology by 24 h. This ability of CM was found (1) to remain after dialysis and lyophilization, (2) to be modulated by steroid treatment of C6 monolayers (PC12 cells only) and (3) to be distinct from the influence of NGF. Combinations of CM, nerve growth factor (NGF) and dibutyryl cyclic AMP when given together in pairs to PC12 or PCG2 cells revealed facilitation of neurite formation and cell morphology, respectively. These results suggest possible synergistic interaction between the three factors in the neuroglial regulation of neuronal morphological differentiation.
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PMID:Glial-released proteins: III. Influence on neuronal morphological differentiation. 626 4

The nerve growth factor protein (NGF) stimulates neurite outgrowth form embryonic sensory ganglia and sympathetic ganglia at all stages of development. In addition, NGF is required for the maintenance of the differentiated state in adult sympathetic ganglia. A clonal cell line, IMR-32, derived from a human neuroblastoma was found to contain a population of cells that respond to NGF by exhibiting morphological differentiation. The effect of NGF on these cells is compared with that of other agents known to induce differentiation of IMR-32, including glioma-conditioned media.
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PMID:Induction of neurite outgrowth in the IMR-32 human neuroblastoma cell line by nerve growth factor. 627 84

The precise role of the nerve growth factor protein (NGF) during the growth and development of the human nervous system is not determined. Although it appears to influence a number of neural functions, its mechanism of action is poorly understood. A number of researchers have proposed that NGF may be involved in several pathological conditions including cancer. It has been shown that NGF is secreted by certain sarcoma (23), neuroblastoma (113), and glioma (7,102,136) cell lines and can bind to neuroblastoma and metastatic melanoma cell lines (42). Neuroblastoma (136,181) and pheochromocytoma (165) cells in vitro can be induced by NGF to differentiate toward a morphologically "more benign" state and appropriate NGF treatment of rats can reduce the number of chemically induced gliomas and neurinomas (174,178). NGF can also reduce the growth of intracerebrally inoculated anaplastic glioma cells (172). Anti-NGF treatment of rats (178) and mice (179) can alter the tumor distribution observed following ethylnitrosourea or benzo(a)pyrene treatment (10). In humans, it has been reported that serum levels of NGF are usually elevated in persons "at risk" for neurofibromatosis (156). The precise nature of the NGF role is not known in these instances. Further understanding of the action of NGF could be of clinical importance.
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PMID:Nerve growth factor and neural oncology. 630 Apr 14

A trypsin-degradable nerve growth factor (NGF) receptor associated with the phospholipid component of the surface membrane has been detected on F98 anaplastic glioma cells. NGF also bound to the nucleus of F98 cells. Bound NGF was not displaceable by insulin, cytochrome C, growth hormone, or bovine serum albumin. Specific binding of NGF occurred with a Kd of 8.79 X 10(-12) M as determined by Scatchard analysis with approximately 34,000 receptors per cell. Specific NGF binding was also evident to C6 rat glioma cells and IMR-32 human neuroblastoma cells, but not to 3T3 mouse fibroblasts. These observations coupled with previous findings suggest that the NGF receptor may be a marker found on cells of neural derivation. As little as 1 ng/ml NGF caused an increase in the adhesiveness of F98 cells to culture flasks. Increased adhesiveness could be observed in as little as 5 min and was apparent for at least 45 min. At 25 min in NGF-containing medium, 24 +/- 3% of the cells adhered to the flasks compared to 13 +/- 1% of control cells. The NGF-induced increase in adhesiveness was not duplicated by epidermal growth factor, insulin, cytochrome c, bovine serum albumin, dibutyryl cyclic AMP, or sodium butyrate. Oxidized NGF blocked the effect of native NGF, but had little or no adhesion-promoting activity itself. Pretreatment of the cells with NGF was also effective in promoting adhesion, even though nerve growth factor was not added to the binding medium. The effect of this pretreatment was reversible; when NGF-pretreated cells were grown in medium without supplemental NGF, the adhesiveness of the cells returned to control levels or lower.
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PMID:Increased adhesion response of anaplastic glioma cells to nerve growth factor and the presence of specific receptors. 631 24

Tetanus toxin (TT) binding to cultured rat and bovine adrenal medullary cells has been investigated using indirect immunofluorescence and anti-dopamine-beta-hydroxylase (DBH) antibodies as a probe to identify catecholaminergic cells. TT binds to all rat adrenal medullary cells which display a neuronal phenotype induced by treatment with nerve growth factor and/or medium conditioned by C6 glioma cells. In contrast, 90-95% of the rounded DBH-positive cells are TT-negative, suggesting that in vitro-transdifferentiation of rat chromaffin cells alternates the expression of membrane properties. Cultured bovine chromaffin cells have no TT binding sites independent of their morphological phenotype.
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PMID:Tetanus toxin binding to different morphological phenotypes of cultured rat and bovine adrenal medullary cells. 635 5

A serum-free culture of dissociated neurons from embryonic rat hippocampus has been established as a rapid and quantitative in vitro test system for neurotrophic signals in the mammalian brain. By means of this cell culture bioassay, a novel low molecular weight neurotrophic factor (NTF) could be identified. NTF is essential for in vitro brain neuron development, promoting survival and neurite outgrowth. The diffusible factor is synthesized and secreted into serum-free defined medium by cultured astrocytes from rat cerebral hemispheres. The number of viable neurons responding to NTF by neurite outgrowth is dependent on the concentration of the factor. Fractionation of astroglial conditioned medium by gel filtration on columns of Sephadex G-10 recovered biological activity of NTF in a single sharp peak corresponding to an apparent molecular weight of approximately equal to 500. NTF is stable to heat and cold and resistant to trypsin and pronase. Unlike nerve growth factor, NTF has no apparent effect on the neurite outgrowth of peripheral neurons. NTF-like activity is present in situ in the mammalian brain, in certain other nonneural tissues, and in C6 and B12 glioma cell conditioned media.
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PMID:Neurotrophic factor for central neurons. 636

The effects of medium conditioned by rat C6 glioma cells (C6-CM) on the survival, neurite formation, and catecholamine content of adrenal medullary cells in culture were investigated and compared with the effects of nerve growth factor (NGF). Adrenal medullary cells were isolated from 10-day-old rats and the proportions of surviving and neurite-extending cells were determined after 8 days in culture. In the presence of C6-CM virtually all seeded cells survived and 50% developed neuritic processes. In contrast, NGF did not support survival above control levels (30%) and induced neurite formation from approximately one-third of the surviving cells. C6-CM and NGF had no additive effects on neurite outgrowth. C6-CM-mediated fiber outgrowth was not inhibited by physiological concentrations of glucocorticoids which abolished the NGF-induced neurite formation. Both C6-CM and NGF increased the catecholamine content of the cultures and reduced the relative content of epinephrine. However, in view of its substantial effect on cell survival as compared to NGF, C6-CM caused a reduction of the catecholamine content per cell. We conclude that adrenal medullary cells, like other members of the sensory-sympathetic cell lineage of the neural crest, respond to glial-conditioned medium. This response differs both quantitatively and qualitatively from that mediated by NGF.
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PMID:C6 glioma cell-conditioned medium induces neurite outgrowth and survival of rat chromaffin cells in vitro: comparison with the effects of nerve growth factor. 637 11

Known and unknown host factors determine the individual susceptibility to carcinogenic agents. Such factors may interact with either the phase of transformation (initiation) or with the phase of proliferation (promotion). Some of these factors have been recognized as potential determinants of the degree of susceptibility or resistance to cancer. Transformation may be impeded by a low rate of absorption of carcinogenic agents (barrier effect), by the availability of deactivating enzymes operative at several steps of the metabolism of carcinogenic agents, and by a high repair capability of DNA damage. Proliferation of transformed cells may be impeded or prevented by immune defense mechanisms and by maturation factors such as nerve growth factor (NGF), glia maturation factor, fibroblast growth factor, and others. NGF has already been shown to be capable of maturing anaplastic glioma cells (clone F98) and reducing their rate of growth. Rats treated with NGF following implantation of anaplastic glioma cells had a significantly decreased tumor growth rate and increased survival time. NGF administration to pregnant rats preceding exposure to ethylnitrosourea (ENU) (50 mg/kg, 21st day of gestation) or to offspring transplacentally exposed to ENU resulted in reduction of neurinoma development. The importance of NGF as a suppressing agent of neoplastic proliferation and as a prospective tumor therapeutic needs further exploration.
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PMID:Potential factors in carcinogenesis and tumor regression. 685 28

The effect of nerve growth factor (NGF) and medium conditioned by glioma cells (GCM) on the survival of chicken sensory neurons in culture was investigated. Neurons were isolated from embryos 8 days (E8) to 16 days (E16) old and the proportion of surviving neurons was determined after 2 days in culture. In the absence of NGF or GCM, essentially no neurons survived at any age. In the presence of NGF, survival increased from 25% of the neurons at E8 to 40% between E10 and E12 and then decreased to background level (5%) at E16. In contrast, in the presence of GCM, survival increased continuously from 10% of the neurons at E8 to 75% at E16. At early developmental stages, the effect of NGF and GCM together was greater than the sum of their individual effects: at E8, about 80% of the neurons survived, double the number expected for a simple additive effect. Thus, a significant proportion of chicken neurons from dorsal root ganglia require both NGF and GCM for survival, and this may well include neurons from the ventro-lateral population, which do not respond to NGF alone. As neurons matured, the double requirement progressively decreased and, by E16, NGF no longer increased the number of neurons over that surviving in response to GCM alone. The facts that rat brain extracts mimicked the effect of GCM and that the potency of the brain extracts of rat in the postnatal period increased in parallel with the development of the glial cells suggest that glial cells produce a factor(s) both immunologically and functionally different from NGF which supports the survival of sensory neurons.
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PMID:Sensory neurons in culture: changing requirements for survival factors during embryonic development. 692 68

The effect of rat submaxillary extract on the growth of rat C6 glioma cells in serum-free culture has been examined. Extracts (10-15 microgram/ml) of submaxillary glands from both male and female rats markedly enhanced the growth of serum-deprived C6 cells and, in combination with insulin, transferrin, and NIH-LH (a source of fibroblast growth factor), were able to stimulate C6 cell growth to an extent comparable to that achieved with an optimal amount of fetal calf serum. The mitogenic activity of rat submaxillary extracts was found to be heat-labile, acid-stable, and partially inactivated by protease and 2-mercaptoethanol. Under our assay conditions, biologically active preparations of purified mouse submaxillary gland epidermal growth factor (EGF) or nerve growth factor (NGF) were not mitogenic for C6 cells, nor was the mitogenic activity of rat submaxillary extracts inhibited by antiserum to these mouse submaxillary gland growth factors. These results suggest that the active component(s) of rat submaxillary extracts is unrelated to either EGF or NGF. The growth-enhancing effect also appears unrelated to esteropeptidase activity present in these extracts since the mitogenic activity was unaffected by several protease inhibitors. Moreover, two purified mouse submaxillary gland arginylesteropeptidases, EGF-binding protein and gamma-subunit of 7 S NGF, were unable to elicit a comparable growth response even when added to cell culture medium at unreasonably high concentrations. The C6 cell mitogenic activity of crude submaxillary extracts could be separated into two biologically similar components by either gel filtration on Sephadex G-100, preparative isoelectric focusing in a pH gradient of 3-10, or adsorption to DEAE-cellulose followed by elution with a sodium chloride gradient. One of the active components was acidic in nature and had an apparent molecular weight of 40,000, while the other was near neutral in charge and possessed a molecular weight of approximately 20,000. The relationship between these two C6 cell mitogenic components and the rat submaxillary gland component responsible for stimulating Balb/c-3T3 cell growth in serum-free, factor supplemented medium (McClure et al., 1979, J. Cell Biol. 83:96a) is also discussed.
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PMID:Factors in the rat submaxillary gland that stimulate growth of cultured glioma cells: identification and partial characterization. 697 45


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