Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.2.1.23 (beta-galactosidase)
14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Inositol 1,4,5-trisphosphate receptor (IP3R) is an inositol 1,4,5-trisphosphate (InsP3)-gated Ca2+ release channel. Type 1 IP3R (IP3R1) is the neuronal member of the IP3R family in the CNS and is predominantly expressed in cerebellar Purkinje cells. To elucidate the molecular mechanisms responsible for coupling gene expression to neuronal InsP3/Ca2+ signaling, we have studied the structure and function of the 5'-flanking region of the mouse IP3R1 gene. The cloned 5'-flanking region has several sequences sharing identity with motifs for known transcriptional regulation. We have fused 5'-flanking regions 1N from -528 to +169 and 4N from -4,187 to +169 to a beta-galactosidase gene (lacZ) as a reporter marker and have characterized their in vivo gene expression. Both 1N and 4N fusion genes functioned as a strong promoter in a neuroblastoma-glioma hybrid cell line NG108-15. Moreover, both 1N and 4N transgenic mouse lines carrying these 1N and 4N fusion genes showed characteristic patterns of beta-galactosidase activity in the CNS that are almost consistent with that of the endogenous IP3R1 protein, thereby suggesting that the 1N region from -528 to +169 contains sequence elements responsible for regulating gene expression in neurons and for specifying predominant expression in cerebellar Purkinje cells.
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PMID:Functional expression of the type 1 inositol 1,4,5-trisphosphate receptor promoter-lacZ fusion genes in transgenic mice. 878 3

The use of whole immunoglobulin G (IgG) and F(ab')2 of the G-22 monoclonal antibody associated with cationic liposomes (immunoliposomes) and the effect of repeated exposure were investigated for the transfection of the LacZ gene to various glioma cell lines. Immunoliposomes associated with either whole IgG or F(ab')2 monoclonal antibody caused an about 2-fold increase in beta-galactosidase activity compared with liposomes associated with no antibody in glioma cell lines expressing the CD44 antigen. beta-Galactosidase activity was further increased by about 2-fold by repeated exposure compared with single exposure. A glioma cell line not expressing the CD44 antigen showed no such increase in beta-galactosidase activity. These results indicate that repeated exposure of cationic immunoliposomes achieves a higher transfection efficiency and is a potentially effective method of gene therapy for patients with malignant glioma.
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PMID:Repeated exposure to cationic immunoliposomes activates effective gene transfer to human glioma cells. 886 48

The efficacy of gene therapy for glioma was examined using adeno-associated virus (AAV)-based vectors to deliver genes to experimental tumors in mice. Stereotactic injection of 2 x 10(5) U-251SP human glioma cells into the brains of nude mice produced tumors of 19.06 +/- 1.79 mm2 17 days after injection. Employing a high titer preparation of AAV vector containing the gene for beta-galactosidase (AAV-lacZ), dose-dependent transduction of U-251SP cells was seen in vitro. When 1.6 x 10(10) AAV-lacZ particles were directly injected into tumors in vivo, 30-40% of the cells along the needle track expressed beta-galactosidase. Transduction of U-251SP cells in vitro with an AAV vector containing a bicistronic gene encoding both herpes simplex thymidine kinase and human interleukin-2 (AAV-tk-IRES-IL2) rendered them sensitive to the cytocidal effects of ganciclovir (GCV) and IL-2 was produced in a dose-dependent manner. Cocultures of AAV-tk-IRES-IL2 transduced cells and nontransduced cells proved highly sensitive to GCV indicating the contribution of the bystander effect. Stereotactic delivery of 6 x 10(10) AAV-tk-IRES-IL2 particles into day 7 tumors in nude mice followed by administration of GCV for 6 days, resulted in a 35-fold reduction in the mean volume of tumors compared with controls. Normal brains did not suffer from any toxic effect of the administration of AAV-tk-IRES-IL2 and GCV. These results indicate that high titer AAV vector treatment may be safe and effective for in vivo gene therapy of human brain tumors.
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PMID:Gene therapy against an experimental glioma using adeno-associated virus vectors. 894 Jun 35

Diffuse invasion of brain tissue by single tumor cells is a characteristic feature of gliomas and a major reason why these tumors cannot be completely resected. The molecular basis of brain invasion is poorly understood. We regulated the expression of beta 1 integrins, the major group of extracellular matrix receptors, in astrocytic tumor cells by using a tetracycline-dependent transcription control system. Rat C6 glioma cells were stably transfected with (a) the tetracycline-controlled transactivator (tTA) gene, (b) antisense beta 1 cDNA under the control of a tTA/tetracycline-responsive promoter, and (c) the beta-galactosidase (lacZ) gene for histochemical identification. In one clone, C6TL beta, beta 1 protein levels were unaffected in the presence of tetracycline, but they were reduced by 60% in the absence of tetracycline because of production of antisense mRNA. C6TL beta cells were transplanted into the striatum of nude mice. After 14 days in the presence of tetracycline in the drinking water, tumors showed diffuse brain invasion, mainly along vascular basement membranes. In the absence of tetracycline, however, tumor cells were compact and generally well delineated from the surrounding brain tissue. These data, ie, blocking of brain invasion by antisense beta 1 mRNA, either because of disturbed interaction of beta 1 with brain extracellular matrix components or interference with beta 1-dependent signaling pathways, strongly suggest that beta 1 integrins are required for diffuse brain invasion of gliomas.
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PMID:Diffuse brain invasion of glioma cells requires beta 1 integrins. 897 77

Increased metabolic activity represented by an increase in both anabolism and catabolism in tumours, including gliomas, is a well known phenomenon and utilised in positron emission tomography imaging of tumours. In this study lysosomal enzyme activities of some glycohydrolases were investigated in glioma tissue from human brain. Tumour tissue (ten cases) and brain tissue surrounding the tumour tissue (seven cases) from patients with a histopathological diagnosis of glioblastoma multiforme or anaplastic astrocytoma were analysed for activity of the lysosomal enzymes galactosylceramidase, glucosylceramidase, beta-galactosidase, beta-N-acetyl-glucosaminidase, beta-glucuronidase and acid phosphatase. All of the investigated lysosomal enzymes except galactosylceramidase showed increased activity compared with that in normal brain tissue. Moreover, despite sparsity of tumour cells the specimens taken from surrounding areas showed elevated activities of the same enzymes. The findings indicate an upregulation of the activity not only in tumour but also in normal cells of the surrounding area.
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PMID:Increased activity of lysosomal glycohydrolases in glioma tissue and surrounding areas from human brain. 908 73

Glioma tumour growth is associated with the expression of insulin-like growth factors I and II (IGFs) and of both type I and type II IGF receptors. It has also been shown that IGFs can stimulate proliferation of cultured glioma cells. We previously reported that histamine too can stimulate the growth of glioma cells in vitro. In this report, we study whether the histamine-induced growth of G47 glioma cells is mediated by the IGFs. We found that histamine stimulates the expression of both IGF-I and IGF-II mRNAs, as determined by a semiquantitative in situ hybridization analysis. Furthermore, incubation of G47 cells with histamine also induced cellular immunostaining for IGF-II. It could be shown that IGF-I-stimulated proliferation is inhibited by IGFBP-3, which decreases the availability of IGFs for binding to the IGF receptors, and by beta-galactosidase, which may decrease IGF binding to the type II IGF receptor, but is not inhibited by the anti-type I IGF receptor monoclonal antibody alphaIR3. However, neither IGFBP-3 nor beta-galactosidase nor alphaIR3 inhibited the histamine-induced proliferation. These results show that the growth-stimulatory effect of histamine is accompanied by the induction of IGFs. This histamine-induced growth stimulation is not mediated by activation of cell surface IGF receptors, although intracrine activation of type II IGF receptors may be involved.
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PMID:Histamine-stimulated expression of insulin-like growth factors in human glioma cells. 909 54

In order to realize a novel vaccination treatment for malignant gliomas using tumor cells genetically modified to express certain cytokines, it is essential to achieve an efficient gene transduction into primary cultured cells. We investigated the feasibility of preparing a glioma vaccine through retrovirus-mediated gene transduction. Glioma cells were cultured primarily from surgically resected tumor tissues of six patients. We obtained more than 1000-fold proliferation of cultures within eight weeks in all six cases. In vitro infection with a recombinant retrovirus GKlacZ carrying an Escherichia coli beta-galactosidase marker gene resulted in over 65% gene transfer to the primary cultured glioma cells. Further enrichment (approximately 90%) of transduced cells was possible by employing repeated infections or using vectors with neo' marker gene. Two cytokine genes, granulocyte-macrophage colony-stimulating factor and interleukin-4, were introduced into glioma cells by sequential transduction with two single-expression GK vectors. The transduced glioma cells produced high levels of both cytokines. We also evaluated simultaneous introduction of two genes with double-expression GK vectors containing internal ribosomal entry site (IRES) or internal promoter (PGK). Although the cells transduced with double-expression vectors secreted both cytokines, the level of the gene product following IRES or PGK was 10 times lower than that of the upstream gene product. The transduced cells retained cytokine secretion in vitro for 14 days after 100 Gy irradiation. Our data indicate the feasibility of retrovirus-mediated preparation of gene-modified tumor vaccines from clinical glioma materials, which could be useful for potentiating antitumor immunity in glioma patients.
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PMID:Efficient retrovirus-mediated cytokine-gene transduction of primary-cultured human glioma cells for tumor vaccination therapy. 914 Jan 15

A reporter gene (lac-z) was introduced into rat (BT4C) and human (D-54 MG) proliferating glioma cell lines by means of liposomal transfection. Lac-z-transfected glioma cells were first cultured as multicellular spheroids and then confronted with fetal brain aggregates. After various intervals the lac-z reporter gene product, bacterial beta-galactosidase, was histochemically detected in the cocultures. beta-Galactosidase was only detected in the glioma cells which showed an intense blue staining, which made them easily distinguishable from fetal tissue. Both glioma cell lines showed a clear pattern of migration and increasing invasion with time as the tumor cells infiltrated and destroyed the brain aggregates. Spheroid growth curves showed no significant differences between transfected and nontransfected cell lines. Likewise, flow cytometry measurements revealed no significant changes in ploidy between transfected and nontransfected rat glioma cells. In comparison, a shift in ploidy was observed in the human glioma cells after lac-z transfection. Stable integration of the lac-z gene into tumor cells was verified by Southern blot analysis. The results indicate that transfection of the lac-z reporter gene into glioma cells lines does not affect their growth or invasion potential in vitro. The lac-z reporter gene can thus be exploited to facilitate visualization of single migrating tumor cells and quantification of tumor invasion in in vitro coculture systems.
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PMID:The lac-z reporter gene: a tool for in vitro studies of malignant glioma cell invasion. 918 46

p16INK4A is a G1-specific cell cycle inhibitor which maps to human chromosome 9p21, a region frequently mutated or deleted in cancer cell lines and primary tumors. In glioblastomas the frequency of homozygous deletions is 40-70% making it one of the most common mutations in this tumor type. We have analysed the significance of the loss of this gene in gliomas by introducing the cDNA for p16INK4A into the human glioma cell line U-1242 MG which has a deleted CDKN2 locus. We used the tetracycline repressible vector system and obtained two stably transfected clones that expressed p16INK4A upon induction. p16INK4A expression caused a G1 arrest and enlargement of the cells similar to that of senescent cells. When staining for Senescence-Associated beta-galactosidase activity, described to be specific for senescent cells, we could show that the enlarged cells specifically gave a positive staining reaction. This senescence phenotype was dependent on the continuous expression of p16INK4A since it was reversed upon reintroduction of tetracycline suppression. Thus, the induced expression of p16INK4A in these glioma cells reverted their immortal phenotype and caused an immediate cellular senescence.
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PMID:Induction of senescence in human malignant glioma cells by p16INK4A. 924 4

Up-regulation of vascular endothelial growth factor (VEGF) expression is a major event leading to neovascularization in malignant gliomas. Hypoxia is believed to be the crucial environmental stimulus for this up-regulation. To critically assess this hypothesis, we asked whether the mechanisms defined previously for hypoxia-induced VEGF expression in vitro are similarly involved and sufficient for up-regulation of VEGF gene expression in vivo, using a lacZ reporter gene under the control of VEGF regulatory sequences in an experimental glioma model. Inclusion of the binding site for hypoxia-inducible factor 1 (HIF 1) in the 5' regulatory sequences used in the hybrid gene produced weak beta-galactosidase staining in a special tumor cell subtype, the so-called perinecrotic palisading (PNP) cells that flank necrotic regions within the tumor. Deletion of the HIF 1 binding site abolished reporter gene expression in the PNP cells, indicating that transcriptional activation of VEGF expression in gliomas is mediated by HIF 1. Inclusion of 3' untranslated sequences from the VEGF gene in the reporter constructs resulted in an increased beta-galactosidase staining in the PNP cells, suggesting that mRNA stabilization also contributes to VEGF up-regulation in glioblastoma cells growing as solid tumors. Combination of the 5' flanking region including the HIF 1 site along with 3' untranslated sequences produced increased levels of beta-galactosidase expression in PNP cells. EF 5 immunostaining for regions of low oxygen partial pressure covered the same PNP cells that were stained for beta-galactosidase. Collectively, the data provide experimental evidence that VEGF gene expression is activated in a distinct tumor cell subpopulation, the perinecrotic palisading cells of gliomas, by two distinct hypoxia-driven regulatory mechanisms.
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PMID:Up-regulation of vascular endothelial growth factor expression in a rat glioma is conferred by two distinct hypoxia-driven mechanisms. 928


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