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)

Recent studies have demonstrated that ectopic glycoprotein hormones only partially bind Con A. To investigate the basis for these findings, the Con A binding of ectopic hCG beta from DoT cervical carcinoma cells was examined after digestion with various glycosidases. Ectopic hCG beta only partially bound Con A, as was the case after digestion with neuraminidase and beta-galactosidase. However, subsequent digestion with N-acetylhexosaminidase increased Con A binding to 96%. It is apparent that Con A binding of ectopic hCG can be inhibited by a residue removed by N-acetylhexosaminidase, probably extra beta-N-acetylglucosamine linked to beta-mannose on N-linked oligosaccharides. The method used involved the glycosidase digestion of glycoprotein alkylated under denaturing conditions and was first validated with milligram amounts of standard hCG beta.
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PMID:Use of glycosidase digested human chorionic gonadotropin beta-subunit to explain the partial binding of ectopic glycoprotein hormones to Con A. 679 92

We report on an in vivo delivery system that attenuates the growth, in nude mice, of a malignant human breast cancer cell line containing a p53 mutation. Nude mice, inoculated with breast carcinoma cells, were injected every 10-12 days with a liposome-p53 complex via the tail vein. A significant reduction of greater than 60% in primary tumor volume was observed as compared to the control groups. Furthermore, when individual growth patterns of the tumors were assessed, we found that primary tumor size regressed in the majority of p53-treated animals (8/15), whereas only one tumor in the control groups (1/22) regressed. The eight tumors that regressed with the liposome-p53 complex showed no evidence of relapse for 1 month after the cessation of treatment. We also determined that the administration of the liposome-p53 complex reduced the incidence of metastases. The MDA-MB-435 tumor cells, transduced with the lacZ gene, facilitated quantitation of beta-galactosidase activity and tumor burden in the lungs. The number of metastatic cells in the lung was significantly lower in the p53-treated group (0.53 +/- 0.43 x 10(6), p < 0.01) than in either the vector-treated (8.1 +/- 3.7 x 10(6)) or untreated control groups (15.8 +/- 5.9 x 10(6)). Thus, systemic administration of the liposome-p53 complex reduced not only the size of the primary tumors but, more importantly, prevented the relapse and metastases of these tumors.
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PMID:Systemic gene therapy with p53 reduces growth and metastases of a malignant human breast cancer in nude mice. 761 97

The human breast carcinoma cell line T47D is known to express high-affinity calcitonin receptors (CTRs). PCR amplification of the CTR cDNA from T47D mRNA resulted in the identification of two different cDNAs that encode distinct receptor isoforms, h alpha CTR and h beta CTR. The two cDNAs are identical except that the h alpha CTR cDNA contains a 48 bp insert sequence that encodes a 16 amino acid domain in the first cytosolic loop of the receptor. Stable transfection of each receptor cDNA into murine erythroleukaemia (MEL) cells resulted in the expression of receptors with high affinity for radiolabelled salmon calcitonin (h alpha CTR Kd 0.09 nM, h beta CTR Kd 0.12 nM). Ligand competition binding studies did not reveal any significant pharmacological difference between the receptor isoforms. In transfected MEL cells and COS-1 cells the h beta CTR isoform was expressed at tenfold higher levels than the h alpha CTR. A reporter gene assay that monitored the coupling of CTR to adenylate cyclase by increases in beta-galactosidase activity indicated that both receptors were able to stimulate cyclic AMP production in response to ligand binding.
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PMID:Identification of multiple human calcitonin receptor isoforms: heterologous expression and pharmacological characterization. 761 7

Endo-beta-galactosidase from Escherichia freundii cleaves linear polylactosamine structure as follows: R-GlcNAc-beta 1-3Gal-beta 1-4GlcNAc-beta 1-R' + H2O-->R-GlcNAc-beta 1-3Gal + GlcNAc-beta 1-R'. Staining with Griffonia simplicifolia agglutinin II (GSA-II) following enzyme digestion reveals the distribution of R-GlcNac-beta 1-3Gal-beta 1-4GlcNAc-beta 1-R' structures in tissue sections. In this study, the procedure was applied to formalin-fixed, paraffin-embedded tissue sections from 26 cases of papillary carcinomas including 2 follicular variants, 8 follicular carcinomas, 7 adenomas, 1 anaplastic carcinoma and 1 medullary carcinoma in order to investigate whether different types of polyactosamine-containing structure are produced in these thyroid neoplasms. Simultaneously, the susceptibility of the ABH antigens expressed in these neoplastic cells to endo-beta-galactosidase digestion was examined. Most of the papillary carcinoma cells from all the individuals examined were strongly stained by GSA-II following enzyme digestion. Without enzyme digestion, little or no reactivity with GSA-II was observed. Among other types of neoplasms, only one case of follicular carcinoma exhibited reactivity with GSA-II following enzyme digestion. ABH antigens were expressed in 22 cases of papillary carcinomas, 2 adenomas, 5 follicular carcinomas and 1 anaplastic carcinoma, and their expression was dependent on the ABO blood group of the patients. Endo-beta-galactosidase digestion resulted in the elimination of these antigens not only in papillary carcinomas but also in other neoplasms.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Histochemical differences of the lectin affinities of backbone polylactosamine structures carrying the ABO blood group antigens in papillary carcinoma and other types of thyroid neoplasm. 777 98

A MAb 9F6 was capable of staining HPV16 E7 in a human cervical carcinoma line, CaSki, and rat 3Y1 cells stably expressing HPV16 E7 gene. Contrary to the current understanding of E7 as a nuclear protein, the site of staining was clearly cytoplasmic. The subcellular localization of E7 was further studied by using the beta-galactosidase (beta-gal) receptor method. A fusion protein composed of E7 and beta-gal was stably expressed in rat 3Y1 cells. The beta-gal activity in these cells was detected mostly in the nucleus, even though 9F6 still stained the cytoplasm of these cells. The fusion protein was also found to be oncogenic since transfected 3Y1 cells acquired transformed phenotypes such as increased saturation density and anchorage-independent growth. These results indicate that biologically active E7 exists mostly in the nucleus, but nuclear E7 is masked from 9F6. A series of deletion mutants of E7 further demonstrated that the amino acid sequence from 16 to 41 was enough to transport beta-gal into the nucleus. A mutation either at amino acid 24 or 26 which is known to disrupt the binding of E7 to RB, the retinoblastoma gene product, did not strongly affect the nuclear localization of the fusion protein, suggesting that the nuclear transportation of E7 is mostly independent of RB binding.
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PMID:Nuclear localization and transforming activity of human papillomavirus type 16 E7-beta-galactosidase fusion protein: characterization of the nuclear localization sequence. 794 47

The immunohistochemical reactivity of a second generation murine monoclonal antibody (LU-BCRU-G7), raised against a novel fucosylated glycoprotein of M(r) 2300,000, has shown a significant association with prognosis of early stage carcinomas. Staining was observed in 72% of the 190 breast carcinomas tested. No relationship with steroid receptor status, stage or node status was found. An association with grade was observed (chi 2 7.83, 2 degrees of freedom, P = 0.02) only when the negative cut-off level was raised from < 10% cells staining to < 25%. Antibody reactivity was always cytoplasmic. Immunoblotting shows the antibody is reactive with a component of M(r) 230,000 not detected by HMFG 2. A significant association was found between lack of reactivity and improved disease-free interval (0.005 > P > 0.001) and survival (0.02 > P > 0.01). Subdivision of cases on the basis of node status showed that staining could refine survival data. A decreased reactivity of LU-BCRU-G7 was observed after pretreatment with beta-galactosidase but not a sialidase or beta-N-acetylhexosaminodase indicating that non-reducing terminal galactose residues in beta 1-3 or beta 1-4 linkages may be involved in the antibody binding site. This approach has identified a useful and novel prognostic marker in early stage human breast carcinoma.
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PMID:Prognostic value of a breast cancer-associated glycoprotein detected by monoclonal antibody LU-BCRU-G7. 794 64

To better understand the events occurring during immunotherapy of liver metastases with effector cells, we have developed a clinically relevant animal model in which both effector-tumor cell interactions and survival can be evaluated. A cell line of human gastric carcinoma (HR) metastatic to the liver has been established from a patient's liver biopsy. HR cells (10 x 10(6)) injected intrasplenically metastasize into the liver of immunosuppressed nude mice, with micrometastases detectable histologically by day 4 and macrometastases by day 7. The animals subsequently develop ascites and die between days 30 and 40 after tumor injection. To investigate early metastatic events in the liver, HR cells were transduced with a plasmid containing both the lacZ gene under the control of the CMV promoter and NeoR gene. Transfectants selected for neomycin resistance were lacZ gene positive and stained blue in the presence of a beta-galactosidase substrate, 5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside (X-Gal). These transfectants (HRLZ) remained lacZ gene positive for at least 25 passages in vitro. Injected intrasplenically, an HRLZ clone grew invasively in nude mice and formed liver metastases comparably to parental tumor cells. The number and localization of blue X-Gal-positive tumor cells were followed in liver tissues of animals sacrificed at various times, from 1 h to 28 days postinjection of HRLZ cells. HRLZ cells were seen in liver blood vessels and sinusoids within 1 h after injection, and the progressive growth of micrometastases and macrometastases could be followed with precision by X-Gal staining. On day 3 after injection of HRLZ cells, numerous micrometastases were established containing 12-16 tumor cells. When these 3-day established HRLZ micrometastases were treated by the intrasplenic infusion of interleukin 2 (IL2)-activated human natural killer (NK) cells selected by IL2-induced adherence to plastic (A-NK) and systemic IL2, nearly all liver micrometastases were eliminated within 24 h after a single transfer of A-NK cells (P < 0.001). This xenogeneic model was also used for adoptive immunotherapy of 7-day established liver macrometastases with human A-NK cells injected intrasplenically and exogenous IL2 given i.p. A significant decrease in the number of hepatic metastases and the weight of livers (P < 0.003) in comparison with those of control mice was observed.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Immunotherapy of liver metastases of human gastric carcinoma with interleukin 2-activated natural killer cells. 803

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

The potential efficacy and clinical feasibility of gene therapy for prostate cancer were tested. Efficacy was tested using the Dunning rat prostate carcinoma model. Rats with anaplastic, hormone refractory prostate cancer treated with irradiated prostate cancer cells genetically engineered to secrete human granulocyte-macrophage colony-stimulating factor (GM-CSF) showed longer disease-free survival compared to either untreated control rats or rats receiving prostate cancer cell vaccine mixed with soluble human GM-CSF. A gene modified prostate cancer cell vaccine thus provided effective therapy for anaplastic, hormone refractory prostate cancer in this animal model. An evaluation of the clinical feasibility of gene therapy for human prostate cancer based on these findings was then undertaken. Prostate cancer cells from patients with stage T2 prostate cancer undergoing radical prostatectomy were first transduced with MFG-lacZ, a retroviral vector carrying the beta-galactosidase reporter gene. Efficient gene transfer was achieved in each of 16 consecutive cases (median transduction efficiency 35%, range 12 to 65%). Cotransduction with a drug-selectable gene was not required to achieve high yield of genetically modified cells. Histopathology confirmed malignant origin of these cells and immunofluorescence analysis of cytokeratin 18 expression confirmed prostatic luminal-epithelial phenotype in each case tested. Cell yields (2.5 x 10(8) cells per gram of prostate cancer) were sufficient for potential entry into clinical trials. Autologous human prostate cancer vaccine cells were then transduced with MFG-GM-CSF, and significant human GM-CSF secretion was achieved in each of 10 consecutive cases. Sequential transductions increased GM-CSF secretion in each of 3 cases tested, demonstrating that increased gene dose can be used to escalate desired gene expression in individual patients. These studies show a preclinical basis for proceeding with clinical trials of gene therapy for human prostate cancer.
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PMID:Demonstration of a rational strategy for human prostate cancer gene therapy. 830 72

Successful antiestrogen treatment in patients with tamoxifen-responsive breast tumors is often followed by an outgrowth of tumors cells that are antiestrogen resistant, implying that estrogen-dependent tumors can become estrogen-independent. In an effect to mimic this progression, we have transfected fibroblast growth factor 4 into MCF-7 cells, a human breast carcinoma cell line that is estrogen-dependent for growth in nude mice. This transfection results in cell lines that form progressively growing, metastatic tumors when injected s.c. into untreated or tamoxifen-treated ovariectomized nude mice. In contrast to the parental cell line, growth of transfected cells in ovariectomized nude mice is stimulated by tamoxifen treatment and inhibited by estrogen treatment of the mice. Parental MCF-7 cells were transfected with an expression vector for beta-galactosidase, conferring the ability to convert the chromogenic substrate, 5-bromo-4-chloro-3-indoyl-beta-galactoside, to a blue color and allowing the detection of their presence within tumors developing after coinoculation with fibroblast growth factor 4-transfected cells. The fibroblast growth factor 4-transfected cells could support growth and metastasis of the beta-galactosidase-expressing parental cell line when both lines were coinjected into the same site in untreated or tamoxifen-treated, ovariectomized mice. These data suggest a possible role for fibroblast growth factors in the progression of breast tumors to an estrogen-independent, antiestrogen-resistant, metastatic phenotype. They also support a role for paracrine factors in mixed populations of tumor cells of differing states of malignant progression.
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PMID:Fibroblast growth factor 4 transfection of MCF-7 cells produces cell lines that are tumorigenic and metastatic in ovariectomized or tamoxifen-treated athymic nude mice. 848 20


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