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Berlin Brandenburg

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  • 1
    Language: English
    In: International Journal of Cancer, 01/03/1996, Vol.65(1), pp.90-96
    Description: Human neuroblastoma cell line UKF-NB-4 persistently infected with human cytomegalovirus (HCMV) strain AD169 was established to study the effects of long-term HCMV infection on virus production and phenotypic characteristics of tumour cells. The cells designated UKF-NB-4 super(AD169) were subcultured (80 subcultures) over a period of more than 2 years after initiation of infection. UKF-NB-4 super(AD169) cells continued to produce infectious virus in successive passages, with a titre ranging from 9 x 10 super(3) to 1 x 10 super(5) and from 2 x 10 super(1) to 2 x 10 super(2) plaque-forming units per 10 super(6) cells and 1 ml culture medium, respectively; 10-20% of the cells produced HCMV-specific antigens, while 6-13% produced infectious virus progeny. The number of HCMV-specific DNA copies ranged from 9 x 10 super(4) to 9 x 10 super(6) per 10 super(6) cells. Transmission electron microscopy confirmed the productive nature of HCMV infection. UKF-NB-4 super(AD169) cultures proliferated, with population doubling time ranging from 24.5 to 26.6 hr (19.5 to 20.3 hr for UKF-NB-4) and cell viability from 79% to 85% (91-96% for UKF-NB-4). Significantly lower amounts of tyrosine hydroxylase and decreased activity for dopamine- beta -hydroxylase than in uninfected cells were observed in UKF-NB-4 super(AD169) cells. However, the expression of N-myc oncoprotein was significantly increased in persistently infected cultures. Our results show that long-term productive HCMV infection of UKF-NB-4 cell line is associated with the modulation of phenotypic properties, which may be related to the biological behaviour of neuroblastoma cells.
    Keywords: Cytomegalovirus ; Cytomegalovirus ; Neuroblastoma Cells ; Man ; Tumor Cells ; Phenotyping ; Neuroblastoma Cells ; Man ; Tumor Cells ; Phenotyping ; Neurovirology ; Virus Behavior in Cell Culture ; Tyrosine 3-Monooxygenase ; Dopamine Beta -Monooxygenase ; N-Myc Protein ; Tyrosine 3-Monooxygenase ; Dopamine Beta -Monooxygenase ; N-Myc Protein ; N-Myc Protein ; Dopamine Beta -Monooxygenase ; Tyrosine 3-Monooxygenase;
    ISSN: 00207136
    E-ISSN: 10970215
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  • 2
    In: Transplantation, 1996, Vol.62(9), pp.1371-1374
    Description: In this study, we investigated the effects of the intracellular metal chelator desferrioxamine (DFO) and the extracellular metal chelator diethylenetriamine penta-acetic acid (DTPA), which were previously shown to have strong anticytomegalovirus potencies, on their ability to elicit immunomodulatory effects in vitro[fcn,3]. The results showed that nontoxic and in vivo attainable concentrations of both DFO and DTPA inhibited mitogen- and allogen-induced proliferation of peripheral blood lymphocytes. The immunomodulatory effects of DFO/DTPA seem to be due to the impaired expression of interleukin-2 receptor and the reduced secretion of interleukin-2. However, metal chelators were more effective than cyclosporine or tacrolimus (FK506) in our in vitro experiments. Moreover, cytotoxicity mediated by lymphokine-activated killer cells and natural killer cells and the expression of HLA and adhesion molecules on cytokine-stimulated endothelial cells were differentially impaired by DFO/DTPA. These results warrant further study of the immunological effects of metal chelators in vivo.
    Keywords: Immunopharmacology ; Immunoregulation ; Metal Chelators ; Desferrioxamine ; Diethylenetriamine Penta-Acetic Acid ; Desferrioxamine ; Diethylenetriamine Penta-Acetic Acid ; Immunoregulation ; Metal Chelators;
    ISSN: 0041-1337
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  • 3
    Language: English
    In: Intervirology, 1996, Vol.39(4), pp.259-269
    Description: Although there is no definitive evidence of the association of human cytomegalovirus (HCMV) infection with human cancers, the oncogenic potential of HCMV has been well established by in vitro studies demonstrating the ability of UV-irradiated or infectious virus to transform a variety of cells. After prolonged passaging the transformed cell type was maintained while HCMV DNA sequences were no more detectable. Three morphological transforming regions (mtr) of HCMV have been identified. The effects of HCMV on cellular functions which may be associated with the malignant phenotype include the expression of oncogenes and transcriptional activation of growth factors and interleukin synthesis. In infected cells, HCMV induces cytoskeletal alterations and changes in expression of cell surface receptors for extracellular matrix proteins which could result in increased motility and dissemination of cancer cells. Several human neuroblastoma cell lines undergo maturation in different neural crest derived cell types upon treatment with oncogenic potential agents, i. e. retinoic acid. The persistent HCMV infection of neuroblastoma cells (〉1 year) is accompanied by the increased expression of oncoproteins (i.e. N-myc) and decreased expression of tyrosine hydroxylase and dopamine-β-hydroxylase. The activation of the cellular metabolism is due to HCMV binding to cellular receptors (prior to virus gene expression) and to the activity of HCMV immediate early (IE) gene products. IE proteins act directly as transcriptional activators or their activity is mediated by a variety of cellular transcription factors. HCMV infection may result in activation of promoters of cellular genes coding for cytokines, replication enzymes, protooncogenes and viral promoters. Recently it has been demonstrated that HCMV IE proteins block apoptosis probably by suppressing the ability of the antioncogene p53 to activate a reporter gene. The interactions of HCMV with tumor suppressor proteins such as p53 or retinoblastoma (pRb) susceptibility protein are reminiscent of those mediated by the oncoproteins of DNA tumor viruses. The acquisition of a fully malignant phenotype by normal cells is thought to require several mutations in a number of cellular genes. In this connection, HCMV may play the role of a nonobligate either direct or indirect cofactor for tumor genesis, e.g. by blocking apoptosis, which may be an essential requirement for tumor progression. Due to the stimulation of growth factors and/or inhibition of antioncogenes by its gene products, HCMV may modulate the malignant potential of tumor cells.
    Keywords: Original Paper ; Cytomegalovirus, Human ; Neuroblastoma ; Oncogenic Potential ; Differentiation ; Biology
    ISSN: 0300-5526
    E-ISSN: 1423-0100
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  • 4
    In: Anti-Cancer Drugs, 1996, Vol.7(7), pp.766-773
    Description: Valproic acid (VPA) is a simple branched-chain fatty acid that has anticonvulsant activity and is widely used in the treatment of epilepsy. VPA was found to effect growth and differentiation of human neuroblastoma (NB) cells in vitro at concentrations that have been achieved in humans with no significant adverse effects. Treatment of UKF-NB-2 and UKF-NB-3 NB cell lines with VPA at concentrations ranging from 0.5 to 2 mM resulted in neuronal morphological differentiation characterized by extension of cellular processes without significant effects on cell viability. Ultra-structural features of VPA-treated cells were consistent with the neuronal type of differentiation. VPA treatment of NB cells was associated with decreased expression of N-myc oncoprotein and increased expression of neural cell adhesion molecule in their membrane. Treatment of NB cells with 0.5 mM VPA increased their sensitivity to lymphokine-activated killer lysis. The results indicate that VPA, at non-toxic pharmacological concentrations, arrests the growth, induces differentiation and increases immunogenicity of NB cells through non-toxic mechanisms.
    Keywords: Antibiotics ; Miscellaneous, Reviews ; Sodium Valproate ; Neuroblastoma ; Neuroblastoma ; Sodium Valproate;
    ISSN: 0959-4973
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