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  • 1
    In: Nature Medicine, 2011, Vol.17(4), p.504
    Description: We simultaneously transduced cells with three lentiviral gene ontology (LeGO) vectors encoding red, green or blue fluorescent proteins. Individual cells were thereby marked by different combinations of inserted vectors, resulting in the generation of numerous mixed colors, a principle we named red-green-blue (RGB) marking. We show that lentiviral vector-mediated RGB marking remained stable after cell division, thus facilitating the analysis of clonal cell fates in vitro and in vivo. Particularly, we provide evidence that RGB marking allows assessment of clonality after regeneration of injured livers by transplanted primary hepatocytes. We also used RGB vectors to mark hematopoietic stem/progenitor cells that generated colored spleen colonies. Finally, based on limiting-dilution and serial transplantation assays with tumor cells, we found that clonal tumor cells retained their specific color-code over extensive periods of time. We conclude that RGB marking represents a useful tool for cell clonality studies in tissue regeneration and pathology. [PUBLICATION ]
    Keywords: Animals–Methods ; Cell Tracking–Cytology ; Clone Cells–Metabolism ; Clone Cells–Genetics ; Color–Metabolism ; Genetic Vectors–Cytology ; Green Fluorescent Proteins–Metabolism ; Green Fluorescent Proteins–Genetics ; Hepatocytes–Metabolism ; Hepatocytes–Genetics ; Liver Regeneration–Metabolism ; Luminescent Proteins–Metabolism ; Luminescent Proteins–Pathology ; Mice–Pathology ; Mice, Inbred C57bl–Pathology ; Mice, Inbred Nod–Pathology ; Mice, Scid–Pathology ; Mice, Transgenic–Pathology ; Neoplasm Transplantation–Pathology ; Recombinant Proteins–Pathology ; Recombinant Proteins–Pathology ; Transduction, Genetic–Pathology ; Tumor Cells, Cultured–Pathology ; Tumor Cells, Cultured–Pathology ; Cell Division ; Cloning ; Cell Growth ; Gene Expression ; Proteins ; Scientific Method ; Luminescent Proteins ; Recombinant Proteins ; Red Fluorescent Protein ; Green Fluorescent Proteins;
    ISSN: 1078-8956
    E-ISSN: 1546170X
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  • 2
    Language: English
    In: 2012, Vol.7(8), p.e43468
    Description: Glioblastomas are highly aggressive brain tumors of adults with poor clinical outcome. Despite a broad range of new and more specific treatment strategies, therapy of glioblastomas remains challenging and tumors relapse in all cases. Recent work demonstrated that the posttranslational hypusine modification of the eukaryotic initiation factor 5A (eIF-5A) is a crucial regulator of cell proliferation, differentiation and an important factor in tumor formation, progression and maintenance. Here we report that eIF-5A as well as the hypusine-forming enzymes deoxyhypusine synthase (DHS) and deoxyhypusine hydroxylase (DOHH) are highly overexpressed in glioblastoma patient samples. Importantly, targeting eIF-5A and its hypusine modification with GC7, a specific DHS-inhibitor, showed a strong antiproliferative effect in glioblastoma cell lines in vitro , while normal human astrocytes were not affected. Furthermore, we identified p53 dependent premature senescence, a permanent cell cycle arrest, as the primary outcome in U87-MG cells after treatment with GC7. Strikingly, combined treatment with clinically relevant alkylating agents and GC7 had an additive antiproliferative effect in glioblastoma cell lines. In addition, stable knockdown of eIF-5A and DHS by short hairpin RNA (shRNA) could mimic the antiproliferative effects of GC7. These findings suggest that pharmacological inhibition of eIF-5A may represent a novel concept to treat glioblastomas and may help to substantially improve the clinical course of this tumor entity.
    Keywords: Research Article ; Biology ; Medicine ; Oncology
    E-ISSN: 1932-6203
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  • 3
    In: Nature Protocols, 2012, Vol.7(5), p.839
    Description: Cells transduced with lentiviral vectors are individually marked by a highly characteristic pattern of insertion sites inherited by all their progeny. We have recently extended this principle of clonal cell marking by introducing the method of RGB marking, which makes use of the simultaneous transduction of target cells with three lentiviral gene ontology (LeGO) vectors encoding red, green or blue fluorescent proteins. In accordance with the additive color model, individual RGB-marked cells display a large variety of unique and highly specific colors. Color codes remain stable after cell division and can thus be used for clonal tracking in vivo and in vitro. Our protocol for efficient RGB marking is based on established methods of lentiviral vector production (3-4 d) and titration (3 d). The final RGB-marking step requires concurrent transduction with the three RGB vectors at equalized multiplicities of infection (1-12 h). The initial efficiency of RGB marking can be assessed after 2-4 d by flow cytometry and/or fluorescence microscopy.
    Keywords: Flow Cytometry ; Cell Division ; Titration ; Progeny ; Multiplicity of Infection ; Color ; Cell Division ; Color ; Flow Cytometry ; Multiplicity of Infection ; Progeny ; Titration ; Animal Diseases;
    ISSN: 1754-2189
    E-ISSN: 17502799
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  • 4
    In: Nature Protocols, 2015, Vol.10(6), p.939
    ISSN: 1754-2189
    E-ISSN: 17502799
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  • 5
    Language: English
    In: Journal of Molecular Medicine, Nov, 2011, Vol.89(11), p.1113(12)
    Description: Byline: Ellen Preuss (1,2), Alexander Muik (3,4), Kristoffer Weber (1), Jurgen Otte (2), Dorothee Laer (4), Boris Fehse (1) Keywords: Suicide gene; HSVtk; Cancer gene therapy; Bystander effect Abstract: Suicide gene therapy is a promising concept in oncology. We have recently introduced a novel suicide gene, TK.007, which was shown to excel established herpes simplex virus thymidine kinase (HSVtk) variants when used for donor-lymphocyte modification in adoptive immunotherapy models. Here, the potential of TK.007 in killing cancer cells was studied. Initially, we transduced tumour cell lines derived from different neoplasias (glioblastoma, melanoma, lung cancer, colon cancer) with lentiviral LeGO vectors encoding TK.007 or the splice-corrected (sc)HSVtk together with an eGFP/Neo-marker. Based on direct in vitro comparison, we found that TK.007 facilitates more efficient tumour cell killing at significantly lower ganciclovir doses in all tumour cell lines tested. Also, using different readout systems, we found a significantly stronger bystander effect of TK.007 as compared to scHSVtk. Importantly, in vitro data were confirmed in vivo using a subcutaneous G62 glioblastoma model in NOD/SCID mice. In mice transplanted with scHSVtk-positive tumours, treatment with low (10 mg/kg) or standard (50 mg/kg) ganciclovir doses resulted only in short-term growth inhibition or transient tumour remission, respectively. In striking contrast, in the TK.007 group, all animals achieved continuous complete remission after both standard and low-dose ganciclovir. Finally, a substantial bystander effect for TK.007 was also confirmed with the G62 model in vivo, where significantly prolonged survival for mice bearing tumours containing only 10% or 50% TK.007-expressing cells was observed. In summary, our data indicate strongly improved anti-tumour activity of TK.007 as compared to conventional HSVtk. We therefore suppose that TK.007 is an excellent candidate for cancer suicide gene therapy. Author Affiliation: (1) Research Department Cell and Gene Therapy, Clinic for Stem Cell Transplantation, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany (2) Frankfurter Stiftung fur krebskranke Kinder, Frankfurt am Main, Germany (3) Georg Speyer Haus, Frankfurt am Main, Germany (4) Virology Section, Medical University Innsbruck, Innsbruck, Austria Article History: Registration Date: 10/06/2011 Received Date: 17/02/2011 Accepted Date: 07/06/2011 Online Date: 23/06/2011
    Keywords: Cancer -- Care And Treatment ; Cancer -- Genetic Aspects ; Cancer -- Research ; Gene Therapy -- Health Aspects ; Gene Therapy -- Research
    ISSN: 0946-2716
    Source: Cengage Learning, Inc.
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  • 6
    Language: English
    In: Journal of Molecular Medicine, 2011, Vol.89(11), pp.1113-1124
    Description: Suicide gene therapy is a promising concept in oncology. We have recently introduced a novel suicide gene, TK.007, which was shown to excel established herpes simplex virus thymidine kinase (HSVtk) variants when used for donor-lymphocyte modification in adoptive immunotherapy models. Here, the potential of TK.007 in killing cancer cells was studied. Initially, we transduced tumour cell lines derived from different neoplasias (glioblastoma, melanoma, lung cancer, colon cancer) with lentiviral LeGO vectors encoding TK.007 or the splice-corrected (sc)HSVtk together with an eGFP/Neo-marker. Based on direct in vitro comparison, we found that TK.007 facilitates more efficient tumour cell killing at significantly lower ganciclovir doses in all tumour cell lines tested. Also, using different readout systems, we found a significantly stronger bystander effect of TK.007 as compared to scHSVtk. Importantly, in vitro data were confirmed in vivo using a subcutaneous G62 glioblastoma model in NOD/SCID mice. In mice transplanted with scHSVtk-positive tumours, treatment with low (10 mg/kg) or standard (50 mg/kg) ganciclovir doses resulted only in short-term growth inhibition or transient tumour remission, respectively. In striking contrast, in the TK.007 group, all animals achieved continuous complete remission after both standard and low-dose ganciclovir. Finally, a substantial bystander effect for TK.007 was also confirmed with the G62 model in vivo, where significantly prolonged survival for mice bearing tumours containing only 10% or 50% TK.007-expressing cells was observed. In summary, our data indicate strongly improved anti-tumour activity of TK.007 as compared to conventional HSVtk. We therefore suppose that TK.007 is an excellent candidate for cancer suicide gene therapy.
    Keywords: Suicide gene ; HSVtk ; Cancer gene therapy ; Bystander effect
    ISSN: 0946-2716
    E-ISSN: 1432-1440
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  • 7
    Language: English
    In: Human gene therapy, August 2010, Vol.21(8), pp.929-41
    Description: Conditional elimination of infused gene-modified alloreactive T cells, using suicide gene activation, has been shown to be an efficient strategy to abrogate severe graft-versus-host disease (GvHD) in the context of adoptive immunotherapy. To overcome shortcomings of the most widely used suicide gene, wild-type (splice-corrected) herpes simplex virus thymidine kinase (scHSVtk), we generated two new variants: the codon-optimized coHSVtk and, by introducing an additional mutation (A168H), the novel TK.007. We transduced human hematopoietic cell lines and primary T cells with retroviral "sort-suicide vectors" encoding combinations of selection markers (tCD34 and OuaSelect) with one of three HSVtk variants. In vitro we observed higher expression levels and sustained long-term expression of TK.007, indicating lower nonspecific toxicity. Also, we noted significantly improved kinetics of ganciclovir (GCV)-mediated killing for TK.007-transduced cells. In an experimental (murine) allogeneic transplantation model, TK.007-transduced T cells mediated severe GvHD, which was readily abrogated by application of GCV (10 mg/kg). Last, we established a modified allotransplantation model that allowed quantitative comparison of the in vivo activities of TK.007 versus scHSVtk. We found that TK.007 mediates both significantly faster and higher absolute killing at low GCV concentrations (10 and 25 mg/kg). In summary, we demonstrate that the novel TK.007 suicide gene combines better killing performance with reduced nonspecific toxicity (as compared with the frequently used splice-corrected wild-type scHSVtk gene), thus representing a promising alternative for suicide gene therapy.
    Keywords: Genes, Transgenic, Suicide ; Genetic Vectors ; Genetic Therapy -- Methods ; Graft Vs Host Disease -- Therapy ; Thymidine Kinase -- Metabolism
    ISSN: 10430342
    E-ISSN: 1557-7422
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  • 8
    Language: English
    In: STEM CELLS, May 2010, Vol.28(5), pp.928-938
    Description: The mammary gland represents a unique model system to study gene functions in adult stem cells. Mammary stem cells (MaSCs) can regenerate a functional epithelium on transplantation into cleared fat pads. We studied the consequences of distinct genetic modifications of MaSCs on their repopulation and differentiation ability. The reconstitution of ductal trees was used as a stem cell selection procedure and the nearly quantitative lentiviral infection efficiency of the primary mammary epithelial cells (MECs) rendered the enrichment of MaSCs before their transplantation unnecessary. The repopulation frequency of transduced MaSCs was nearly 100% in immunodeficient recipients and the resulting transgenic ducts homogeneously expressed the virally encoded fluorescent marker proteins. Transplantation of a mixture of MECs, expressing different fluorescent proteins, resulted in a distinct pattern of ductal outgrowths originating from a small number of individually transduced MaSCs. We used genetically modified MECs to define multiple functions of Stat5 during mammary gland development and differentiation. Stat5‐downregulation in MaSCs did not affect primary ductal outgrowth, but impaired side branching and the emergence of mature alveolar cells from luminal progenitors during pregnancy. Conversely, the expression of a constitutively active variant of Stat5 (cS5‐F) caused epithelial hyperproliferation, thickening of the ducts and precocious, functional alveoli formation in virgin mice. Expression of cS5‐F also prevented involution and caused the formation of estrogen and progesterone receptor positive (ERPR) adenocarcinomas. The tumors expressed activated Stat5 and Stat3 and contained a small fraction of CD44 cells, possibly indicative of cancer stem cells. S C 2010;28:928–938
    Keywords: Tissue‐Specific Stem Cells ; Tissue Regeneration ; Gene Delivery Systems In Vivo Or In Vitro ; Breast Cancer
    ISSN: 1066-5099
    E-ISSN: 1549-4918
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  • 9
    In: Blood Coagulation & Fibrinolysis, 2010, Vol.21(5), pp.464-473
    Description: Postnatal vasculogenesis has been implicated as an important mechanism for neovascularization via bone marrow-derived endothelial progenitor cells (EPCs) circulating in peripheral blood. In preparation of the utilization of EPCs in clinical protocols, we have generated blood-derived EPCs according to two established protocols by culturing either nonadherent mononuclear cells on fibronectin or adherent mononuclear cells on collagen. To explore the feasibility of these EPCs for their potential clinical use as target cells for genetic transduction to enhance their thromboresistance, newly designed retroviral and lentiviral gene ontology expression vectors were tested. Whereas cell clusters derived from the nonadherent cells demonstrated an only limited proliferative potential, cell colonies derived from collagen-adherent cells expanded more than a million-fold. Characterization of the exponentially growing cells by surface antigen and gene expression profiling revealed a consistently strong expression of characteristic endothelial markers, whereas expression of leukocyte markers was gradually lost. Using a single-step transduction protocol, we were able to achieve gene transfer efficiency of up to 99%. Our results suggest that the generated blood-derived EPC population might be attractive target cells for tissue engineering and gene therapy protocols due to their well defined phenotype, extensive proliferative potential, and efficient genetic transducibility, three important qualities that need to be defined prior to any clinical use.
    Keywords: Transduction, Genetic ; Endothelial Cells -- Cytology ; Lentivirus -- Genetics ; Stem Cells -- Metabolism;
    ISSN: 0957-5235
    E-ISSN: 14735733
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  • 10
    Language: English
    In: Neoplasia, December 2010, Vol.12(12), pp.1023,IN10-1030,IN17
    Description: The human immunodeficiency virus (HIV) protease inhibitor saquinavir shows anticancer activity. Although its nitric oxide-modified derivative saquinavir-NO (saq-NO) was less toxic to normal cells, it exerted stronger inhibition of B16 melanoma growth in syngeneic C57BL/6 mice than saquinavir did. Saq-NO has been shown to block proliferation, upregulate p53 expression, and promote differentiation of C6 glioma and B16 cells. The anticancer activity of substances is frequently hampered by cancer cell chemoresistance mechanisms. Therefore, we here investigated the roles of p53 and the ATP-binding cassette (ABC) transporters P-glycoprotein (P-gp), multidrug resistance-associated protein 1 (MRP1), and breast cancer resistance protein 1 (BCRP1) in cancer cell sensitivity to saq-NO to get more information about the potential of saq-NO as anticancer drug. Saq-NO exerted anticancer effects in lower concentrations than saquinavir in a panel of human cancer cell lines. Neither p53 mutation or depletion nor expression of P-gp, MRP1, or BCRP1 affected anticancer activity of saq-NO or saquinavir. Moreover, saq-NO sensitized P-gp-, MRP1-, or BCRP1-expressing cancer cells to chemotherapy. Saq-NO induced enhanced sensitization of P-gp- or MRP1-expressing cancer cells to chemotherapy compared with saquinavir, whereas both substances similarly sensitized BCRP1-expressing cells. Washout kinetics and ABC transporter ATPase activities demonstrated that saq-NO is a substrate of P-gp as well as of MRP1. These data support the further investigation of saq-NO as an anticancer drug, especially in multidrug-resistant tumors.
    Keywords: Medicine
    ISSN: 1476-5586
    E-ISSN: 1476-5586
    Source: ScienceDirect Journals (Elsevier)
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