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)

Malignant brain tumors are characterized by extensive tumor-cell infiltration into the normal brain tissue. The present work describes the migratory behavior of human glioma cells transplanted into the adult rat brain with the aim of exploiting the extent of active cell migration and passive cell displacement within the central nervous system. To detect every transplanted tumor cell, a stably bacterial beta-galactosidase (lac-z) transfected human glioma cell line was used. To distinguish between an active cell migration process and passive cell displacement, rat brains were also implanted with inert fluorescent polystyrene microspheres and the distribution of tumor cells and microspheres was studied 1 hr and 3 days after implantation. One hour after implantation the tumor cells were strictly localized at the implantation site. However, 3 days after implantation, both tumor cells and microspheres showed an extensive distribution within the brain. Confirming earlier neuropathological and experimental studies, it is shown that the lac-z-transfected glioma cells had the capacity to move within the Virchow-Robin and subarachnoid spaces. However, since fluorescent microspheres were also found in these areas, this spread of tumor cells may be primarily mediated by the extensive cerebrospinal fluid flow that exists within the brain. Three days after implantation, the glioma cells also showed an active migration over the corpus callosum. In comparison, the fluorescent microspheres showed only limited spread along the callosal body. It is concluded that the bacterial lac-z gene can be stably transfected into human glioma cells and, since every tumor cell can be visualized within the brain, this model provides a tool for studying the mechanisms behind tumor-cell invasion of the brain.
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PMID:Migratory patterns of lac-z transfected human glioma cells in the rat brain. 755 28

Bacterial beta-galactosidase, coded by lacZ, is a widely used reporter for studies of transcriptional activity of eukaryotic promoters at the single cell level. Unfortunately, current detection methods, like X-gal cytochemistry, are slow, have suboptimal sensitivity, and are incompatible with cell survival. By a novel approach based on microinjection into cells of the fluorogenic substrate 5-chloromethylfluorescein di-beta-D-galactopyranoside lacZ gene expression was detected without affecting cell viability or proliferative capacity. The method was far more sensitive than the conventional X-gal cytochemistry in all cell systems tested (primary hepatocytes, fibroblasts, and glioma cells). Results were obtained within seconds to minutes after injection, and cells remained fluorescent for hours.
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PMID:Sensitive and rapid detection of beta-galactosidase expression in intact cells by microinjection of fluorescent substrate. 764 87

Adenoviral vectors have recently been shown to effectively deliver genes into a variety of tissues. Since these vectors have some advantages over the more extensively investigated retroviruses, we studied the effect of two replication-defective adenovectors bearing human wild type tumor suppressor gene p53 (Adp53) and Escherichia coli beta-galactosidase gene (AdLacZ) on 9L glioma cells. Successful in vitro gene transfer was shown by DNA polymerase chain reaction (PCR), and expression was confirmed by reverse transcriptase RNA PCR and Western blot analyses. Transduction of 9L cells with the Adp53 inhibited cell growth and induced phenotypic changes consistent with cell death at low titers, while AdLacZ caused cytopathic changes only at high titers. Stereotactic injection of AdLacZ (10(7) plaque forming units) into tumor bed stained 25 to 30% of tumor cells at the site of vector delivery. Injection of Adp53 (10(7) plaque forming units), but not AdLacZ (controls), into established 4-day old 9L glioma brain tumors decreased tumor volume by 40% after 14 days. As a step toward gene therapy of brain tumors using replication-defective adenoviruses, these data support the use of tumor suppressor gene transfer for in vivo treatment of whole animal brain tumor models.
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PMID:Adenovirus-mediated p53 gene delivery inhibits 9L glioma growth in rats. 764 77

Among the appealing features of adenoviruses as vectors for transfer of genes into the central nervous system (CNS) are that they are not neurotoxic, they can accommodate the insertion of several large genes, they are not associated with the hazards of insertional mutagenesis, and they can be concentrated to a high-titer preparation. The authors evaluated the feasibility of using adenovirally mediated gene transfer into cultured human glioma cells and in rat models of solid brain tumors and meningeal cancer. Replication-deficient adenoviral vector particles carrying a nuclear-localizing lacZ gene were injected into established 9L cerebral gliomas in Fischer rats. In addition, the adenoviral vector was injected into the subarachnoid space, either simultaneously with intrathecal tumor inoculation or after establishing leptomeningeal cancer. The brains and spinal cords were removed at various intervals for histochemical evaluation for beta-galactosidase activity using X-Gal staining. Additional rats received a stereotactic intracerebral injection of the vector into normal brain. No clinical abnormalities were observed in the injected rats. Injection of the adenoviral vector into normal brain resulted in diffuse transduction of astrocytes, microglia, neurons, and endothelial cells at the injection site. Injection of a high-concentration vector preparation into cerebral gliomas resulted in effective tumor transduction. Intrathecal injection of the vector in rats with meningeal cancer resulted in transduction of the infiltrating tumor in the subarachnoid space when injections were given simultaneously with, or 7 days after, tumor inoculation. Transduction rates of both solid and leptomeningeal tumors correlated with the number of injected particles. These results suggest that adenoviral vectors can efficiently transduce solid brain tumors and that the vectors survive in the cerebrospinal fluid for a sufficient period of time to allow leptomeningeal tumor transduction. Adenoviral vector should be evaluated for its potential use in therapeutic gene transfer approaches in malignancies of the CNS.
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PMID:Adenovirally mediated gene transfer into experimental solid brain tumors and leptomeningeal cancer cells. 781 37

The dismal results of conventional therapy for primary malignant brain tumors has justified exploring gene therapy approaches for this disease. Transduction of animal brain tumor models in vivo has been reported previously with retroviruses and herpes viruses. Because adenoviruses have the advantage of transducing quiescent and actively dividing tumor cells, they may prove to be more effective in such therapy. We used a replication-deficient recombinant adenovirus bearing the Escherichia coli beta-galactosidase gene in a rat C6 glioma tumor model. Transduced cells were detected by X-5-bromo-4-chloro-3-indolyl beta-D-galactoside staining to reveal beta-galactosidase activity. Initial experiments in vitro showed 50% and 90% transduction at vector titers of approximately 10(7) and 10(8) plaque-forming units/ml, respectively. Although no cytopathic effects were seen at 10(7) plaque-forming units/ml, more than 50% reduction in tumor cell growth was noted at 10(8) plaque-forming units/ml both in vitro and in vivo. Stereotactic delivery of the recombinant adenovirus into the frontal lobe of normal rat brains resulted in intense staining of all cell types, that is, neurons, astrocytes, and ependymal cells. Stereotactic injection into C6 glioma brain tumors in rats stained 25 to 30% of the tumor cells. We conclude that adenovirus vectors can be used to transfer genes to central nervous system tumors in vivo. Using stereotactic delivery, adenovirus vectors can transfer genes into the central nervous system intended for tumor therapy.
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PMID:Stereotactic delivery of a recombinant adenovirus into a C6 glioma cell line in a rat brain tumor model. 783 41

The efficacy of adenovirus (ADV)-mediated gene therapy to treat brain tumors was tested in a syngeneic glioma model. Tumor cells were transduced in situ with a replication-defective ADV carrying the herpes simplex virus thymidine kinase (HSV-tk) gene controlled by the Rous sarcoma virus promoter. Expression of the HSV-tk gene enables the transduced cell to convert the drug ganciclovir to a form that is cytotoxic to dividing cells. Tumors were generated in Fischer 344 rats by stereotaxic implantation of 9L gliosarcoma cells into the caudate nucleus. Eight days later, the tumors were injected either with the ADV carrying the HSV-tk (ADV-tk) gene or a control ADV vector containing the beta-galactosidase (ADV-beta gal) gene and the rats were treated with either ganciclovir or saline. Tumor size was measured 20 days after implantation of 9L cells or at death. Rats treated with ADV-beta gal and ganciclovir or with ADV-tk and saline had large tumors. No tumors were detected in animals treated with ADV-tk and with ganciclovir at doses > or = 80 mg/kg. An infiltrate of macrophages and lymphocytes at the injection site in animals treated with ADV-tk and ganciclovir indicated an active local immune reaction. In survival studies, all animals treated with ADV-tk and ganciclovir have remained alive longer than 80 and up to 120 days after tumor induction whereas all untreated animals died by 22 days. These results demonstrate that ADV-mediated transfer of HSV-tk to glioma cells in vivo confers sensitivity to ganciclovir, and represents a potential method of treatment of brain tumors.
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PMID:Adenovirus-mediated gene therapy of experimental gliomas. 788 26

Murine RSV-M glioma cells were genetically labeled with a retroviral BAG vector carrying the Escherichia coli beta-galactosidase gene. The X-gal-positive stable cell line RSV-M/BAG was obtained by the FDG-FACS method. To examine the behavior of glioma cells in the brain, we homografted RSV-M/BAG cells into the brain of C3H/HeN mice as cell suspensions. Individual grafted glioma cells were easily detected by histochemical staining for B-galactosidase (beta-gal). Three days after grafting, the beta-gal-positive cells were mainly found in the subependymal zone of the lateral ventricle. In addition, some solitary labeled cells were found at locations distant from the injection sites. On the seventh day after implantation, tumor masses were observed and graft-derived glioma cells were migrating bilaterally along the fibers in the corpus callosum. Other labeled cells extended into the brain parenchyma via the perivascular (Virchow-Robin) spaces. Rapid and extensive migration of individual glioma cells was thus clearly demonstrated by intracerebral transplantation of RSV-M/BAG cells.
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PMID:Migration of genetically labeled glioma cells after implantation into murine brain. 793 73

The delivery of therapeutic genes to primary brain neoplasms opens new opportunities for treating these frequently fatal tumors. Efficient gene delivery to tissues remains an important obstacle to therapy, and this problem has unique characteristics in brain tumors due to the blood-brain and blood-tumor barriers. The presence of endothelial mitogens and vessel proliferation within solid tumors suggests that genetically modified endothelial cells might efficiently transplant to brain tumors. Rat brain endothelial cells immortalized with the adenovirus E1A gene and further modified to express the beta-galactosidase reporter were examined for their ability to survive implantation to experimental rat gliomas. Rats received 9L, F98, or C6 glioma cells in combination with endothelial cells intracranially to caudate/putamen or subcutaneously to flank. Implanted endothelial cells were identified by beta-galactosidase histochemistry or by polymerase chain reaction in all tumors up to 35 days postimplantation, the latest time examined. Implanted endothelial cells appeared to cooperate in tumor vessel formation and expressed the brain-specific endothelial glucose transporter type 1 as identified by immunohistochemistry. The proliferation of implanted endothelial cells was supported by their increased number within tumors between postimplantation days 14 and 21 (P = 0.015) and by their expression of the proliferation antigen Ki67. These findings establish that genetically modified endothelial cells can be stably engrafted to growing gliomas and suggest that endothelial cell implantation may provide a means of delivering therapeutic genes to brain neoplasms and other solid tumors. In addition, endothelial implantation to brain may be useful for defining mechanisms of brain-specific endothelial differentiation.
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PMID:Endothelial cell implantation and survival within experimental gliomas. 793 75

Immunoliposomes were constructed with an antibody specific to glial cells. They were used to examine the specificity and efficacy of cell type plasmid transfection. Liposomes contained a beta-galactosidase gene under control of an SV-40 promotor. Two different monoclonal antibodies of a different subclass, IgM and IgG, were examined for their targeting ability using immunoliposomes. Cultured C6 glioma (specific target cell type) and NIH 3T3 (control cell type, fibroblast) cells were transfected using these immunoliposomes. Results indicate a three-fold increase in transfection by the glial specific immunoliposomes, "gliasomes", in glial cell culture over control liposomes. Gliasomes were exposed to NIH 3T3 cells and showed no enhanced transfection over control liposomes. Gliasomes were tested for their specificity by the addition of excess antibody to the cell culture in order to saturate specific receptors on C6 glioma cells. Results indicate a reduced transfection, nearly three-fold, in cells that were saturated with excess antibody prior to exposure to the immunoliposomes.
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PMID:Delivery of plasmid DNA to glial cells using pH-sensitive immunoliposomes. 800 28

Gene transfer with vectors derived from murine retroviruses is restricted to cells which are proliferating and synthesizing DNA at the time of infection. This suggests that retroviral-mediated gene transfer might permit targeting of gene integration into malignant cells in organs composed mainly of quiescent nonproliferating cells, such as in the brain. Accordingly, selective introduction of genes encoding for susceptibility to otherwise nontoxic drugs ("suicide" genes) into proliferating brain tumors may be used to treat this cancer. We investigated the efficacy and dynamics of in vivo transduction of growing brain tumors with the herpes simplex-thymidine kinase gene followed by administration of the antiviral drug ganciclovir. Ganciclovir is phosphorylated by thymidine kinase to toxic triphosphates that interfere with DNA synthesis, resulting in the preferential death of the transduced tumor cells. Rats inoculated with 4 x 10(4) 9L gliosarcoma cells into the frontal lobe were treated 7 days later with an intratumoral stereotaxic injection of murine fibroblasts (NIH 3T3 cells) that were producing a retroviral vector containing the herpes simplex-thymidine kinase gene. Controls received vector producer and nonproducer NIH 3T3 cell lines containing the Escherichia coli lacZ (beta-galactosidase) gene as well as nonproducer NIH 3T3 cells containing the thymidine kinase gene. The animals were rested for 7 days to allow time for in situ transduction of the proliferating tumor cells with the herpes-thymidine kinase retroviral vector. The animals were then treated with ganciclovir, 15 mg/kg i.p. twice a day for 14 days. Gliomas receiving an injection of 3-5 x 10(6) thymidine kinase producer cells regressed completely in 23 of 30 rats given ganciclovir therapy, while 25 of 26 control rats developed large tumors. Intratumoral injection of a lower concentration of thymidine kinase vector producer cells (1.8 x 10(6)) resulted in a lower frequency of tumor regression (5 of 13 rats). To estimate the efficiency of in vivo gene transfer, 9L brain tumors were given injections of 5 x 10(6) beta-galactosidase vector producer cells. 5-Bromo-4-chloro-3-indolyl-beta-D-galactopyranaside staining revealed maximal staining of beta-galactosidase within the tumor 7-14 days after injection of the vector producer cells. In vivo transduction rates in harvested tumors ranged from 10 to 70%. There was no evidence of transduction of the surrounding normal neural tissue. Occasional blood vessel endothelial cells within or adjacent to the tumor were observed to be 5-bromo-4- chloro-3-indolyl-beta-D-galactopyranaside positive.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:In situ retroviral-mediated gene transfer for the treatment of brain tumors in rats. 803 19


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