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)

The growth and metastatic behavior of three human tumor cell lines and a human colon carcinoma previously passaged in vivo were compared between nude mice and scid mice after xenotransplantation. The three human tumor lines included a bladder carcinoma (T24B), a melanoma (RPMI 7931) and a lacZ gene-transduced breast cancer (MDA-MB-435 BAG). The lacZ gene codes for beta-galactosidase, which can be stained blue with chromogenic substrate X-gal, thus allowing the highly sensitive detection and quantitative examination of human cancer metastasis in host mice. Adult (7-14 weeks) NMRI nude and C.B-17 SCID mice were inoculated with 0.5-5 x 10(6) tumor cells s.c. Comparable take rate, latent period and growth rate of implanted tumors were observed in nude and scid mice for each of the cell lines tested. At the time of autopsy, which varied from 6 to 11 weeks after inoculation, a significantly higher incidence of spontaneous lung metastasis was discovered in scid mice (96%) than in age-matched nude mice (27%, total P less than 0.001). In vitro assays for NK cell-mediated cytotoxicity revealed no significant differences between the two strains of mice. Our results suggest that nude and scid mice are equally suitable for propagating human tumors. However, the metastatic capacity of human tumor cells appears to be better expressed in scid mice. Scid mice may therefore provide an advantageous model for the study of human tumor metastasis.
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PMID:Comparative studies between nude and scid mice on the growth and metastatic behavior of xenografted human tumors. 158 90

Human fetal lung rudiments (8-12 weeks of development) undergo considerable growth upon microsurgical ectopic implantation in the xenograft-tolerant SCID mouse, and differentiate into a lung-like tissue that includes: (i) bronchial structures lined with pseudostratified, secretory, ciliated epithelium surrounded by smooth muscle and cartilage rings, (ii) submucosal glands, and (iii) alveolar sacs. Normal expression of the cystic fibrosis transmembrane conductance regulator (CFTR) protein was detected by immunostaining in those grafts, and similar differentiation was observed from either normal or cystic fibrosis (CF) fetal lung rudiments. Upon microinjection into human CF or normal lung grafts in SCID mice, beta-galactosidase-adenovirus gene constructs were efficiently transduced into epithelial and glandular cells. Such an in vivo replica of the human respiratory tissue may be a useful experimental model to study normal and pathologic lung development, and to assay candidate therapeutic gene constructs preclinically.
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PMID:Gene transfer to human fetal pulmonary tissue developed in immunodeficient SCID mice. 753 Apr 95

In man, deficiency of ADA activity is associated with an autosomal recessive form of severe combined immunodeficiency (SCID), a disease with profound defects both cellular and humoral immunity. Current treatments of ADA deficient patients include bone marrow transplantation, enzyme replacement and somatic gene therapy. The mechanism of the selective immune cell pathogenesis in ADA-SCIDS is, however, still poorly understood. Thus, the generation of an ADA deficient mouse model will be of considerable benefit to understand better the pathophysiology of the disorder and to improve the gene therapy treatments. We have disrupted the adenosine deaminase (ADA) gene in embryonic stem cells using a new efficient promoter trap gene-targeting approach. To this end, a dicistronic targeting construct containing a promoterless IRES beta geo cassette was used. This cassette allows, via the internal ribosomal entry site (IRES), the direct cap-independent translation of the beta geo reporter gene which encodes a protein with both beta-galactosidase and neomycin activities. After indentification of targeted clones by Southern blot, successful inactivation of the ADA gene was first confirmed by producing, from our heterozygote clones, an homozygote cell line. This line shows no ADA activity as judged by zymogram analysis. Second, we have been able to detect in the targeted clones, a specific beta galactosidase activity using a sensitive fluorogenic assay. The targeted ES cell clones are currently being injected into blastocysts to create an ADA deficient mouse model.
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PMID:Disruption of the adenosine deaminase (ADA) gene using a dicistronic promoterless construct: production of an ADA-deficient homozygote ES cell line. 765 14

Epstein-Barr virus (EBV) is a herpesvirus that transforms B-cells (B-LCL) and has undergone intense scrutiny owing to its association with Burkitt's lymphoma, nasopharyngeal carcinoma, and immunoblastic lymphomas. B-LCL have also proven useful in the study of human immunology. We describe a novel system for inducing efficient foreign gene expression in B-LCL using biotinylated adenovirus as an endosome-disrupting agent. Plasmid DNA is coupled to the exterior of viral particles by streptavidin-polylysine chimeric proteins. Up to 67% of B-LCL may be induced to express foreign genes in vitro in transient expression systems, and gene expression lasts for at least 17 days. We have expressed firefly luciferase, beta-galactosidase (beta-gal), chloramphenicol acetyltransferase, HIV gag, and env genes, as well as infectious HIV, and the EBV-specific BZLF gene in B-LCL with this system. In vivo delivery of a beta-gal reporter gene to B-LCL was documented in a SCID mouse model. Potential applications include study of genetic regulation of EBV infection and transformation events, study of potential gene therapies for EBV-related B-cell tumors, and production of antigen-presenting cells for use in immunologic assays. Because of the high percentage of cells transformed and the length of foreign gene expression, the possibility of examining foreign gene expression in transient assays, without selection for clonal populations, exists.
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PMID:Efficient foreign gene expression in Epstein-Barr virus-transformed human B-cells. 829 Dec 40

Five commonly used cationic liposome formulations were tested for their ability to deliver DNA to established subcutaneous human tumor xenografts in SCID mice. Liposomes were complexed with a mammalian expression plasmid containing the bacterial beta-galactosidase gene and delivered to tumors by direct injection. The optimal lipid to DNA ratios in vivo were markedly different than those observed in vitro for each liposome formulation. Tumor size at the time of inoculation also effected transfection efficiency significantly. Of the five liposome formulations tested, DC-Cholesterol was found to be superior to all others in vivo. Even under optimal conditions however, the efficiency of in vivo transfection was low in our system (approximately 0.3%). Implications of these results for in vivo gene therapy of tumors are discussed.
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PMID:Evaluation and optimization of different cationic liposome formulations for in vivo gene transfer. 866 Mar 30

The human interleukin-2 (IL-2) gene was successfully delivered into established human tumor xenografts in SCID (severe combined immunodeficient) mice by cationic liposome-mediated DNA delivery. A bicistronic mammalian expression vector containing a reporter gene (beta-galactosidase) and human IL-2 cDNA was complexed with either lipofectin or DC-cholesterol liposomes and transferred to tumor xenografts by direct intratumoral injection. Transfection of tumors was confirmed by staining of tumor sections for beta-galactosidase activity and by reverse transcription-polymerase chain reaction (RT-PCR) for the presence of IL-2 mRNA. Growth suppression of tumor xenografts was observed in animals injected with plasmid-liposome complexes but not in animals that received liposomes or naked plasmid only. Complete tumor regression, mediated by the mouse natural killer cells, was observed in 50-80% of the mice treated with the plasmid containing the IL-2 cDNA. The effectiveness of the treatment was dependent on the transfection efficiency and the tumor size at the start of therapy. An initial IL-2 independent suppression of tumor growth was also observed with a plasmid carrying only the beta-galactosidase gene but this effect was temporary and did not lead to tumor regression. These results establish that human tumor xenografts growing in SCID mice can be transfected in vivo by liposome mediated gene delivery and that both IL-2-dependent and IL-2-independent factors may contribute to the tumor suppression observed here.
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PMID:In vivo cytokine gene therapy of human tumor xenografts in SCID mice by liposome-mediated DNA delivery. 881 48

The herpes simplex virus thymidine kinase gene is the most widely utilized toxin for selective killing of carcinoma cells. Expression of the viral thymidine kinase gene renders cells sensitive to the toxic effects of nucleoside analogs such as ganciclovir. An advantage of this system is the "bystander effect" whereby thymidine kinase transduced tumor cells elicit a toxic effect on surrounding nontransduced tumor cells. Ovarian carcinoma appears to be an ideal candidate for gene therapy as the majority of women present with advanced stage disease, have poor prognosis for long-term survival and have the disease confined within the peritoneal cavity. Therefore the utility of an adenoviral vector to elicit an in vitro bystander effect in ovarian carcinoma cells and the therapeutic efficacy of such a system in vivo was undertaken. Immunocompetent animals were utilized to determine the maximum dose of adenovirus that could be administered without any undesirable side effects and that preimmunization had no effects on subsequent challenge. SCID mice were orthotopically transplanted with human ovarian carcinoma cells and, after establishment of tumor, given a recombinant adenovirus expressing either the herpes simplex virus thymidine kinase or the Escherichia coli beta-galactosidase gene. Half the animals from each viral group were treated with either a ganciclovir regiment (50 mg/kg daily for 14 days) or an equal volume of serum-free media. A subset of mice were killed following drug treatment and analyzed for tumor reduction. The remaining animals were followed daily for survival. The animals treated with the recombinant adenovirus expressing the herpes simplex virus thymidine kinase gene and ganciclovir had significant reduction in overall tumor burden and demonstrated statistically significant prolongation in overall survival.
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PMID:Adenoviral-mediated delivery of herpes simplex virus thymidine kinase results in tumor reduction and prolonged survival in a SCID mouse model of human ovarian carcinoma. 887 59

The expression of exogenous genes in long-lived primary T cells is potentially beneficial for the treatment of various diseases including cancer, AIDS, genetic defects of the lymphoid compartment, and systemic enzyme deficiencies such as hemophilia. One approach for genetic modification of T cells is to introduce therapeutic genes into hematopoietic stem cells that would give rise to cells of the lymphoid lineage. Efficient gene transfer and expression in stem cells is often problematic, however. A more direct approach is to introduce the genes into mature primary T lymphocytes since the transferred genes can be maintained and expressed for long periods by long-lived peripheral T cells. In this report, we describe the adoptive transfer into SCID mice of both murine and human primary T cells that have been efficiently transduced with exogenous genes. Primary murine T cells transduced with a retroviral vector containing the human adenosine deaminase (ADA) gene persisted for at least 5 months in lymphoid organs of SCID mice, continuously expressing the exogenous gene. Primary human T cells were also used as target cells for transfer of the beta-galactosidase (lacZ) gene. Expression of the lacZ gene could be detected in over 20% of the transduced primary T cells before adoptive transfer into SCID mice. Transduced human T cells were injected into SCID mice intraperitoneally (ip), and the beta-galactosidase activity could be detected in cells collected from peritoneal exudate washes of recipient mice 6 weeks post-injection. These results demonstrate the availability of a murine model in which the long-term effects of expression of exogenous genes in both murine and human T cells can be tested.
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PMID:A murine model for genetic manipulation of the T cell compartment. 891 90

Herpes simplex virus type 1 (HSV-1) represents a promising new viral vector capable of efficient transduction of myofibers in vivo. Here we report on the use of a replication-defective HSV-1 mutant vector (DZ) deleted for the essential immediate early (IE) gene ICP4 for studies of reporter gene transfer and expression following direct inoculation of mouse skeletal muscle. The recombinant vector was engineered to contain the Escherichia coli lacZ gene under transcriptional control of the strong human cytomegalovirus (HCMV) IE promoter. The effect of vector cytotoxicity on the durability of transgene expression following infection of muscle cells in culture and myofibers in vivo revealed that this first-generation HSV vector was cytopathic, limiting the persistence of vector-transduced cells. UV irradiation of vector preparations reduced viral cytotoxicity for myoblasts in culture without reducing significantly beta-galactosidase production. Moreover, muscle cell viability and the durability of transgene expression was enhanced by several days following UV inactivated-vector infection in vivo. Nevertheless, the viral DNA was subsequently lost from vector-inoculated muscle tissue within 2 weeks. This observation indicated that vector toxicity alone did not account for the lack of persistent transgene expression. Longer-term vector transduction and transgene expression was observed, however, following inoculation of immunodeficient SCID mice, indicating that host immunocompetence played an important role in determining the duration of transgene expression in animals. To support this hypothesis, cells expressing CD4 and CD8 antigens have been found in the HSV-1 injected muscle of immunocompetent mice. These data demonstrated that both vector toxicity and vector-induced immunity are significant obstacles to the use of HSV-1 vectors for muscle gene transfer. These impediments must be overcome to further develop HSV vectors for muscle gene therapy applications.
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PMID:LacZ gene transfer to skeletal muscle using a replication-defective herpes simplex virus type 1 mutant vector. 905 19

DNA-based immunization of mice by intramuscular injection of antigen-encoding plasmid DNA results in immune responses which may be sustained for extended periods of time without an antigen boost. For example, we have previously shown that a strong humoral response against hepatitis B virus surface antigen (HBsAg) will persist for up to 74 weeks following a single intramuscular administration of DNA. It has been proposed that the longevity of the response is due to sustained expression of antigen in transfected muscle cells. However, here we show by immunohistochemistry and electron microscopy that HBsAg-expressing muscle fibers are destroyed around 10 days after injection of DNA in mice. We have also evaluated destruction of the transfected muscle fibers indirectly, by measurement of luciferase activity in muscles at different times after injection of a luciferase reporter gene construct, alone or in combination with HBsAg-expressing DNA. Control muscles injected with luciferase-expressing DNA alone maintain expression of high levels of luciferase for at least 60 days. In contrast, muscles co-injected with DNAs expressing luciferase and a secreted form of HBsAg show high levels of luciferase activity at 5 days but > 99% of this is lost by 20 days. Similar results are obtained with co-expression of luciferase and beta-galactosidase, a non-secreted antigen. Loss of luciferase expression does not occur in muscles of mice with severe combined immunodeficiency, indicating that the myofiber destruction is immunologically mediated.
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PMID:Immune-mediated destruction of transfected muscle fibers after direct gene transfer with antigen-expressing plasmid DNA. 913 31


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