Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0017638 (glioma)
 30,880 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have explored the potential for cloning novel neurotrophic factor cDNAs via assay of neurotrophic activities following expression in Xenopus oocytes. In this report, we describe the successful application of the method to tract rat ciliary neurotrophic factor (CNTF) activity from mRNA purified from cultured cells and from mRNA synthesized by in vitro transcription of a cDNA library. Rat C6 glioma cells, which had been previously shown to have CNTF-like activity (Westermann et al., 1988), were used as source material. We tested protein extracts of C6 cells using an in vitro assay of primary neurons from the chick ciliary ganglion (CCG assay) and detected a CNTF-like activity. RNA isolated from C6 cells was shown to direct the synthesis of the activity following microinjection into Xenopus oocytes and one-step fractionation of Xenopus extract. C6 mRNA was size-fractionated, and fractions encoding CNTF-like activity were cloned into a lambda phage vector at a site distal to a T7 promoter. Synthetic RNA transcribed from total library DNA was injected into Xenopus oocytes, and a CNTF-like activity in the oocyte extract was detected by the CCG assay. Further fractionation of library clones narrowed the presence of the clone encoding the CNTF-like activity to a pool containing 20,000 members. The presence of a full-length CNTF cDNA clone in this pool and partial clones in other pools was confirmed by Polymerase Chain Reaction (PCR) using oligonucleotides from the rabbit CNTF cDNA (Lin et al., 1989) as primers.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Expression cloning of neurotrophic factors using Xenopus oocytes. 162 43

Amitotic [3H]thymidine-labeled C6 glioma cells, which are known to produce neurotrophic factor(s), were grafted alone and with adrenal chromaffin cells in an attempt to improve chromaffin cell survival and phenotypic differentiation. Long-Evans rats with unilateral 6-hydroxydopamine-induced lesions of the nigrostriatal pathway were divided into four groups: (1) those receiving adrenal medullary cells co-transplanted with C6 glioma cells; (2) those receiving adrenal medullary graft alone; (3) those receiving C6 glioma grafts alone; and (4) those serving as a vehicle control group. All rats were killed one month after transplantation. Immunohistochemical, neurochemical, and autoradiographic methods were used to identify and characterize the grafted cells. Tyrosine hydroxylase-immunoreactive cells were found in all animals that received grafts of the adrenal medulla alone or of adrenal medulla co-transplanted with C6 glioma cells. The cograft recipients had more tyrosine hydroxylase-immunoreactive cells than the hosts receiving just adrenal chromaffin cells (P less than 0.05). Additionally, more grafted chromaffin cells formed processes in the former group. All three tissue recipient groups (adrenal medullary, C6 glioma cell, and cografted animals) had a significant reduction (P less than 0.05) in ipsilateral rotations after amphetamine (0.5 mg/kg i.p.) injections as compared to the control vehicle recipient group. Moreover, the reduction in rotation was more marked in the cografted hosts than in the other two implanted groups (P less than 0.05). Significantly higher dopamine levels were found in the transplant sites of both cograft and adrenal medullary graft recipients than in sham grafted control animals.
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PMID:Cografts of adrenal medulla with C6 glioma cells in rats with 6-hydroxydopamine-induced lesions. 197 69

A cDNA encoding a novel human neurotrophic factor (designated nerve growth factor-2; NGF-2) was cloned from a human glioma cDNA library using a synthetic DNA corresponding to human nerve growth factor (NGF). The cloned cDNA encodes a polypeptide composed of 257 amino acid residues including a prepro-sequence of 138 residues and a mature region of 119 residues. The amino acid sequence of human NGF-2 exhibits 58% similarity with that of human NGF. Conditioned medium of COS-7 cells transfected with an expression plasmid for human NGF-2 cDNA supported the survival of sensory neurons isolated from dorsal root ganglia of embryonic chicks. A 1.5 kb of NGF-2 mRNA can be detected from an early development stage in rat brain, by Northern blotting analysis.
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PMID:Cloning and expression of a cDNA encoding a novel human neurotrophic factor. 236 67

When nerve-growth factor (NGF) was added to 17-day fetal rat central nervous system (CNS) septal neurons in culture using a defined medium, choline acetyltransferase (ChAT) activity was greatly induced. However, glioma-conditioned medium (GCM), which is expected to contain cholinergic neurotrophic factor(s) different from NGF, did not affect the ChAT activity of the cultured septal neurons. On the contrary, ChAT activity of 19-day fetal rat hippocampal neurons in culture was increased by the addition of GCM but not by NGF. These phenomena were confirmed in septal and hippocampal neuronal cultures obtained from the same embryonic day, i.e., 18-day fetal rat. The NGF-mediated increase in ChAT activity of cultured septal neurons was culture-time dependent (2.3-fold increase after 3 and 3.5-fold increase after 6 days in culture) and NGF-dose dependent (the ED50 value was 0.8 ng/ml). The effect of NGF was completely abolished by the addition of specific anti-NGF antibodies. The differential effects of NGF and GCM on several other cultured cholinergic neurons from 17-day fetal rat spinal cord, striatum, brainstem and amygdala were measured. NGF tended to increase ChAT activities of cultured striatal and amygdala neurons but not cultured spinal cord and brainstem neurons. GCM increased ChAT activities in the latter two cultures, while having no effect on the former cultures. Although the extent of increase of NGF-mediated ChAT activities of cultured striatal and amygdala neurons were low, NGF-mediated increase of the striatal ChAT activity showed the pattern resembling that of cultured septal neurons as to time-course, dose-dependency and anti-NGF antibody sensitivity. NGF did not affect the tyrosine hydroxylase activity in the cultured brainstem catecholaminergic neurons.
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PMID:Differential effects of nerve-growth factor and glioma-conditioned medium on neurons cultured from various regions of fetal rat central nervous system. 377 32

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 monosialoganglioside GM1 has been shown to possess neurotrophic activity in vitro and in vivo and is now used as an experimental treatment for a variety of neurological disorders and trauma. Little is known about the mechanism of action used by GM1. Because GM1 appears to enhance nerve growth factor (NGF) activity, we have used C6trk+ cells, a derivative of C6-2B glioma cells that express the high-affinity receptor for NGF trkA, to determine whether the neurotrophic effects of GM1 occurs through induction of trkA activity. Exposure of C6trk+ cells to NGF (10-50 ng/ml) resulted in a five- to 10-fold increase in trkA tyrosine phosphorylation within 5 min. Incubation of cells with GM1 resulted in a threefold increase in trkA phosphorylation beginning within 1 h and peaking between 3 and 6 h. Optimal responses to GM1 were obtained using 80-100 microM concentrations. Moreover, tyrosine phosphorylation of known trkA target proteins, such as extracellular signal-regulated kinases, and suc-associated neurotrophic factor-induced tyrosine-phosphorylated target, were activated upon stimulation of C6trk+ cells with GM1. In addition, GM1 potentiated the NGF-mediated activation of tyrosine phosphorylation of trkA. GM1 failed to induce phosphorylation of trkA and target proteins in mock transfected cells. Thus, our data demonstrate that GM1 mimics some of the effects of NGF and suggest that the neurotrophic properties of GM1 may be attributed to its activation of trkA signal transduction.
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PMID:GM1 ganglioside activates the high-affinity nerve growth factor receptor trkA. 779 Aug 79

Cells that lack the high affinity receptor component (trkA) for nerve growth factor (NGF) are unresponsive to NGF. We investigated whether C6-2B cells, a rat glioma derived cell line, express trkA and, as a consequence, are responsive to NGF. In these cells, NGF (100 ng/ml) failed to induce the mRNA encoding for c-fos protooncogene and the low affinity NGF receptor p75NGFR, two NGF-responsive genes. In contrast, both mRNAs were induced in PC12 cells by NGF. Using a RNase protection assay with a cRNA probe for rat trkA, the expected trkA RNA protected fragment was detected in PC12 but not in C6-2B glioma cells, indicating that C6-2B cells either do not express the gene or express it only in low amounts. Cross-linking of 125I-labeled NGF to PC12 cells identified two major bands with an apparent molecular weight of 158 kDa and 100 kDa corresponding to trkA and p75NGFR, respectively. In contrast, only the 100 kDa band could be detected in C6-2B cells by cross-linking analysis. In C6-2B cells stably transfected with the rat trkA cDNA, NGF increased c-fos mRNA, induced tyrosine phosphorylation of gp140trk, and SNT (suc-associated neurotrophic factor-induced tyrosine-phosphorylated target), and caused morphological changes within 72 h. All of these effects of NGF were blocked by the protein kinase inhibitor K-252a suggesting that NGF signal transduction was restored by trkA expression. Most important, in C6trk+ cells, NGF was a weaker (2-fold) inducer of [3H]thymidine incorporation when compared to bFGF (5-fold), suggesting that expression of trkA fails to confer to NGF a strong mitogenic effect. Our findings indicate that C6-2B glioma cells do not possess high affinity NGF receptor and thus are unresponsive to NGF and that expression of trkA in neuroectoderm derived cells elicits some of the NGF responses characteristic of neuronal cells.
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PMID:Induction of nerve growth factor responsiveness in C6-2B glioma cells by expression of trkA proto-oncogene. 786 85

Glia cell line-derived neurotrophic factor (GDNF), a recently cloned member of the transforming growth factor-beta (TGF-beta) superfamily, has been implicated in the survival, morphological and functional differentiation of midbrain dopaminergic neurons and motoneurons in vitro and in vivo. The factor may thus have utility in the treatment of various human neurodegenerative disorders. Mechanisms regulating expression of GDNF in normal and diseased brain as a possible means to increase the local availability of GDNF are only beginning to be explored. We have established and employed a competitive reverse transcriptase-polymerase chain reaction (RT-PCR) to study and compare levels of expression of GDNF mRNA in several cell types and to investigate its regulation. GDNF expression was clearly evident in primary cultured astrocytes, the glioma B49 and C6 cell, but less pronounced in the Schwannoma RN22 cell lines. Little or no signal could be observed in neuroblastoma cell lines (IMR32, LAN-1) or the pheochromocytoma cell line PC12, emphasizing the glial character of this factor. Using the C6 cell line we found that fibroblast growth factor-2 (FGF-2; bFGF) can increase GDNF mRNA levels, whereas FGF-1, platelet-derived growth factor (PDGF), and vasoactive intestinal polypeptide (VIP) are apparently ineffective. Several other factors (forskolin, kainic acid, triiodothyronine dexamethasone, GDNF, TGF-beta 1, and interleukin-6) appear to have slightly negative effects on GDNF mRNA levels at the concentrations tested. To further explore the relationship between FGF-2 and GDNF, we also addressed the question whether GDNF, like FGF-2, may have an effect on C6 cell proliferation. We conclude that (1) glial and glial tumor cells, rather than neuronal cell lines, express GDNF, (2) that FGF-2 has a prominent inductive effect on GDNF expression and (3) that GDNF stimulates C6 cell proliferation. Finally, these data suggest that neurotrophic actions of FGF-2 in mixed glial-neuronal cell cultures might be mediated in part by GDNF.
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PMID:GDNF mRNA levels are induced by FGF-2 in rat C6 glioblastoma cells. 888 50

Persephin (PSP) is the most recently discovered member of the GDNF family of neurotrophic factors. We have used an RT-PCR approach to start addressing the putative functional significance of PSP by determining sites of its synthesis in the neonatal rat brain. Generally, two transcripts were found. Sequence analysis of the transcripts identifies an 88 bp intronic sequence. Neural tissues analysed included cortex, hippocampus, striatum, diencephalon, mesencephalon, cerebellum, hindbrain and spinal cord as well as superior cervical, dorsal root ganglia, adrenal gland, and PC12 pheochromocytoma cells. As non-neuronal tissues, sciatic nerve, optic nerve, primary astroglial, oligodendroglial, O2A progenitor, and glioma cells (C6, B49) were also included. All tissues/cells except oligodendrocytes and O2A progenitor cells were strongly positive for PSP mRNA. To test the hypothesis of whether PSP might act as a target-derived factor, as suggested for GDNF, the motoneuron-muscle axis has been analysed. PSP is synthesized in skeletal muscle and, to a higher extent, in the spinal cord. Moreover, PSP is synthesized in purified embryonic motoneurons. Together, these data do not support a role for PSP as a typical target-derived neurotrophic factor for motoneurons. We conclude that PSP is synthesized throughout the nervous system and that it is presumably of both astroglial and neuronal origin, in contrast to GDNF and neurturin, which seem to be predominantly of neuronal origin.
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PMID:GDNF-related factor persephin is widely distributed throughout the nervous system. 971 Feb 70

Perineural invasion is a prominent clinical feature of pancreatic cancer which causes difficulty in curative resection. In the present study, the human pancreatic cancer cell lines, PaCa-2, AsPC-1, SW1990 and Capan-2, were all found to express abundant c-ret proto-oncogene mRNA and RET protein, a member of the receptor-tyrosine-kinase superfamily, identified as being a receptor for glial-cell-line-derived neurotrophic factor (GDNF). In an invasion assay, the migration of pancreatic cancer cells was markedly induced by co-cultivation with human glioma cells, T98G or A172, capable of producing and secreting GDNF. Anti-GDNF antibody in conditioned media of glioma cells suppressed much of the migratory activity. Checkerboard analysis of the migration showed both chemotactic and chemokinetic activity of GDNF. There was no detectable expression of another GDNF receptor component, a glycosyl-phosphatidylinositol-linked receptor (GFR alpha-1), in pancreatic-cancer cell lines, suggesting that the neural invasion of pancreatic-cancer cells spreads along a concentration gradient of GDNF produced from peripheral ganglions through direct interaction of GDNF with its receptor, the c-ret proto-oncogene product. Immunochemical localization of GDNF in human celiac ganglionic tissue supported this contention.
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PMID:Experimental implication of celiac ganglionotropic invasion of pancreatic-cancer cells bearing c-ret proto-oncogene with reference to glial-cell-line-derived neurotrophic factor (GDNF). 1007 55


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