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1
Rothenberg, S. Michael, Mari N. Olsen, Louise Chang Laurent, Rachel Adams Crowley, and Patrick O. Brown. "Comprehensive Mutational Analysis of the Moloney Murine Leukemia Virus Envelope Protein." Journal of Virology 75, no. 23 (December 1, 2001): 11851–62. http://dx.doi.org/10.1128/jvi.75.23.11851-11862.2001.
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ABSTRACT The envelope (Env) protein of Moloney murine leukemia virus is the primary mediator of viral entry. We constructed a large pool of insertion mutations in the env gene and analyzed the fitness of each mutant in completing two critical steps in the virus life cycle: (i) the expression and delivery of the Env protein to the cell surface during virion assembly and (ii) the infectivity of virions displaying the mutant proteins. The majority of the mutants were poorly expressed at the producer cell surface, suggesting folding defects due to the presence of the inserted residues. The mutants with residual infectivity had insertions either in the amino-terminal signal sequence region, two disulfide-bonded loops in the receptor binding domain, discrete regions of the carboxy-terminal region of the surface subunit (SU), or the cytoplasmic tail. Insertions that allowed the mutants to reach the cell surface but not to mediate detectable infection were located within the amino-terminal sequence of the mature Env, within the SU carboxy-terminal region, near putative receptor binding residues, and throughout the fusion peptide. Independent analysis of select mutants in this group allowed more precise identification of the defect in Env function. Mapping of mutant phenotypes to a structural model of the receptor-binding domain provides insights into the protein's functional organization. The high-resolution functional map reported here will be valuable for the engineering of the Env protein for a variety of uses, including gene therapy.
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Diaz, R. M., T. Eisen, I. R. Hart, and R. G. Vile. "Exchange of Viral Promoter/Enhancer Elements with Heterologous Regulatory Sequences Generates Targeted Hybrid Long Terminal Repeat Vectors for Gene Therapy of Melanoma." Journal of Virology 72, no. 1 (January 1, 1998): 789–95. http://dx.doi.org/10.1128/jvi.72.1.789-795.1998.
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ABSTRACT To generate transcriptionally targeted vectors, tissue-specific elements of the human tyrosinase promoter were exchanged with corresponding viral elements in the Moloney murine leukemia virus long terminal repeat (LTR). From these experiments, a vesicular stomatitis virus type G pseudotyped, hybrid LTR vector that contained three tyrosinase enhancer elements and gave high-level, tightly tissue-specific expression at high titers (3 × 107CFU/ml) was constructed.
3
Hock, RA, AD Miller, and WR Osborne. "Expression of human adenosine deaminase from various strong promoters after gene transfer into human hematopoietic cell lines." Blood 74, no. 2 (August 1, 1989): 876–81. http://dx.doi.org/10.1182/blood.v74.2.876.876.
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Abstract Adenosine deaminase (ADA) deficiency is associated with a fatal severe combined immunodeficiency. Because most patients do not have a suitable marrow donor, the introduction of a normal ADA gene into the patient's marrow cells is a potentially useful alternative therapy. To identify vectors that provide optimal gene expression in human hematopoietic cells, we investigated retroviral vectors containing the ADA gene under the transcriptional control of the promoter/enhancers of Moloney murine leukemia virus, the simian virus 40 early region, the cytomegalovirus immediate-early gene, the lymphotropic papovavirus, and the human beta- globin gene. ADA expression from these vectors was monitored in the ADA- human histiocytic lymphoma cell line DHL-9, and in the multipotential chronic myeloid leukemia cell line K562. ADA expression in infected K562 cells was also measured after induction of megakaryoblastic differentiation by phorbol ester, and after induction of erythroid differentiation by sodium n-butyrate or hemin. In these hematopoietic cell lines, the vectors that contained ADA controlled by either the Moloney murine leukemia virus promoter (LASN) or the cytomegalovirus promoter (LNCA) expressed ADA at much higher levels than the other vectors tested. Furthermore, in K562 cells infected with LASN and LNCA vectors, induction of terminal differentiation resulted in the same or higher level expression of ADA. These cell lines have permitted the evaluation of transduced gene expression in proliferating and differentiating hematopoietic cells that provide a model for bone marrow-targeted gene therapy.
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Hock, RA, AD Miller, and WR Osborne. "Expression of human adenosine deaminase from various strong promoters after gene transfer into human hematopoietic cell lines." Blood 74, no. 2 (August 1, 1989): 876–81. http://dx.doi.org/10.1182/blood.v74.2.876.bloodjournal742876.
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Adenosine deaminase (ADA) deficiency is associated with a fatal severe combined immunodeficiency. Because most patients do not have a suitable marrow donor, the introduction of a normal ADA gene into the patient's marrow cells is a potentially useful alternative therapy. To identify vectors that provide optimal gene expression in human hematopoietic cells, we investigated retroviral vectors containing the ADA gene under the transcriptional control of the promoter/enhancers of Moloney murine leukemia virus, the simian virus 40 early region, the cytomegalovirus immediate-early gene, the lymphotropic papovavirus, and the human beta- globin gene. ADA expression from these vectors was monitored in the ADA- human histiocytic lymphoma cell line DHL-9, and in the multipotential chronic myeloid leukemia cell line K562. ADA expression in infected K562 cells was also measured after induction of megakaryoblastic differentiation by phorbol ester, and after induction of erythroid differentiation by sodium n-butyrate or hemin. In these hematopoietic cell lines, the vectors that contained ADA controlled by either the Moloney murine leukemia virus promoter (LASN) or the cytomegalovirus promoter (LNCA) expressed ADA at much higher levels than the other vectors tested. Furthermore, in K562 cells infected with LASN and LNCA vectors, induction of terminal differentiation resulted in the same or higher level expression of ADA. These cell lines have permitted the evaluation of transduced gene expression in proliferating and differentiating hematopoietic cells that provide a model for bone marrow-targeted gene therapy.
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Seamon, Jennifer A., Kathryn S. Jones, Christina Miller, and Monica J. Roth. "Inserting a Nuclear Targeting Signal into a Replication-Competent Moloney Murine Leukemia Virus Affects Viral Export and Is Not Sufficient for Cell Cycle-Independent Infection." Journal of Virology 76, no. 16 (August 15, 2002): 8475–84. http://dx.doi.org/10.1128/jvi.76.16.8475-8484.2002.
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ABSTRACT The effects of inserting reported nuclear localization signals (NLSs) into the Moloney murine leukemia virus (Mo-MuLV) integrase (IN) protein, within a replication-competent viral construct, were studied. In contrast to the virus harboring IN fused to the simian virus 40 (SV40) large T antigen NLS (SV40 NLS) (J. A. Seamon, M. Adams, S. Sengupta, and M. J. Roth, Virology 274:412-419, 2000), a codon-modified SV40 NLS was stably expressed during viral propagation. Incorporation of the codon-modified SV40 NLS into IN, however, altered the packaging of the Gag-Pol precursor in the virus; viral particles contained decreased levels of reverse transcriptase (RT) and IN. In addition, the virus showed delayed kinetics of viral DNA synthesis upon infection. A panel of infectious MuLVs containing alternative IN-NLS fusions was generated and assayed for cell cycle-independent infection. Viral infection with the NLS-tagged proteins, however, remained dependent on passage of the cells through mitosis. This finding has direct implications for engineering murine-based retroviral vectors for gene therapy.
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Eckert, HG, M. Stockschlader, U. Just, S. Hegewisch-Becker, M. Grez, A. Uhde, A. Zander, W. Ostertag, and C. Baum. "High-dose multidrug resistance in primary human hematopoietic progenitor cells transduced with optimized retroviral vectors." Blood 88, no. 9 (November 1, 1996): 3407–15. http://dx.doi.org/10.1182/blood.v88.9.3407.bloodjournal8893407.
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Retroviral transfer of the multidrug-resistance 1 (mdr1) cDNA into primary human hematopoietic progenitor cells (HPC) of cancer patients undergoing high-dose chemotherapy has been proposed to protect the bone marrow from the dose-limiting cytotoxicity of cytostatic agents. Preclinical studies performed with vectors derived from the Moloney murine leukemia virus (MoMuLV) or the related Harvey murine sarcoma virus have established that chemoprotection of HPC is feasible. The efficacy of vector-mediated multidrug-resistance under high doses of cytostatic agents, however, remained unclear. We report here that this goal can only be achieved with improved vector design. Novel vectors termed SF-MDR and MP-MDR, which are based on the spleen focus-forming virus or the myeloproliferative sarcoma virus for the enhancer and the murine embryonic stem cell virus for the leader, significantly elevate survival of transduced primary human HPC under moderate doses of colchicine and paclitaxel in vitro when compared with a conventional MoMuLV-based vector. Importantly, SF-MDR and also MP-MDR confer an absolute advantage at high doses of paclitaxel in vitro corresponding to peak plasma levels achieved in patients during chemotherapy. This observation has important consequences for a variety of ongoing and planned gene therapy trials.
7
Sharkey, C. Matthew, Cynthia L. North, Richard J. Kuhn, and David Avram Sanders. "Ross River Virus Glycoprotein-Pseudotyped Retroviruses and Stable Cell Lines for Their Production." Journal of Virology 75, no. 6 (March 15, 2001): 2653–59. http://dx.doi.org/10.1128/jvi.75.6.2653-2659.2001.
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ABSTRACT Pseudotyped retroviruses have important applications as vectors for gene transfer and gene therapy and as tools for the study of viral glycoprotein function. Recombinant Moloney murine leukemia virus (Mo-MuLV)-based retrovirus particles efficiently incorporate the glycoproteins of the alphavirus Ross River virus (RRV) and utilize them for entry into cells. Stable cell lines that produce the RRV glycoprotein-pseudotyped retroviruses for prolonged periods of time have been constructed. The pseudotyped viruses have a broadened host range, can be concentrated to high titer, and mediate stable transduction of genes into cells. The RRV glycoprotein-pseudotyped retroviruses and the cells that produce them have been employed to demonstrate that RRV glycoprotein-mediated viral entry occurs through endocytosis and that membrane fusion requires acidic pH. Alphavirus glycoprotein-pseudotyped retroviruses have significant advantages as reagents for the study of the biochemistry and prevention of alphavirus entry and as preferred vectors for stable gene transfer and gene therapy protocols.
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Viejo-Borbolla, A., P. Thomas, E. D. Blair, and T. F. Schulz. "Increase in infectivity of targeted Moloney murine leukemia virus-based gene-delivery vectors through lowering the threshold for fusion." Journal of General Virology 86, no. 9 (September 1, 2005): 2469–80. http://dx.doi.org/10.1099/vir.0.81057-0.
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Many research groups have developed targeted vectors for gene therapy based on Moloney murine leukemia virus (MoMLV). Despite proper binding of the targeted vector to the target molecule, little or no infectivity of human cells expressing the target molecule has been achieved in most studies. One of the reasons for this lack of infectivity may be steric hindrance within the targeted envelope glycoprotein (Env), impeding the conformational changes required for fusion and infection. Here, attempts were made to solve this problem by mutating key residues within Env of two targeted MoMLV-based vectors, MoMLV–E-Sel and MoMLV–FBP. Selection of key residues was based on an Env with reduced threshold for fusion, that of the CD4-independent human immunodeficiency virus type 2 isolate ROD/B. It was shown here that vectors bearing MoMLV–FBP Env with a V512M substitution had higher titres and faster kinetics of entry than vectors bearing parental targeted Env proteins. This could be due to the partial release of steric constraints that result in an Env with a reduced threshold for fusion.
9
van Beusechem, V. W., A. Kukler, M. P. Einerhand, T. A. Bakx, A. J. van der Eb, D. W. van Bekkum, and D. Valerio. "Expression of human adenosine deaminase in mice transplanted with hemopoietic stem cells infected with amphotropic retroviruses." Journal of Experimental Medicine 172, no. 3 (September 1, 1990): 729–36. http://dx.doi.org/10.1084/jem.172.3.729.
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Amphotropic recombinant retroviruses were generated carrying sequences encoding human adenosine deaminase (ADA). Transcription of the human ADA gene was under control of a hybrid long terminal repeat in which the enhancer from the Moloney murine leukemia virus was replaced by an enhancer from the F101 host-range mutant of polyoma virus. Hemopoietic stem cells in murine bone marrow were infected with this virus under defined culture conditions. As a result, 59% of day-12 colony forming unit spleen (CFU-S) stem cells became infected without any in vitro selection. Infected CFU-S were shown to express human ADA before transplantation and this expression sustained upon in vivo maturation. Mice transplanted with infected bone marrow exhibited human ADA expression in lymphoid, myeloid, and erythroid cell types. Moreover, human ADA expression persisted in secondary and tertiary transplanted recipients showing that human ADA-expressing cells were derived from pluripotent stem cells. These characteristics of our amphotropic viruses make them promising tools in gene therapy protocols for the treatment of severe combined immunodeficiency caused by ADA deficiency. In this respect it is also relevant that the viral vector that served as backbone for the ADA vector was previously shown to be nonleukemogenic.
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Barrette, Stephane, Janet L. Douglas, Nancy E. Seidel, and David M. Bodine. "Lentivirus-based vectors transduce mouse hematopoietic stem cells with similar efficiency to Moloney murine leukemia virus–based vectors." Blood 96, no. 10 (November 15, 2000): 3385–91. http://dx.doi.org/10.1182/blood.v96.10.3385.
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Abstract The low levels of transduction of human hematopoietic stem cells (HSCs) with Moloney murine leukemia virus (MLV) vectors have been an obstacle to gene therapy for hematopoietic diseases. It has been demonstrated that lentivirus vectors are more efficient than MLV vectors at transducing nondividing cell lines as well as human CD34+ cells and severe combined immunodeficiency disease repopulating cells. We compared transduction of cell lines and Lin− bone marrow cells, using a vesicular stomatitis virus G (VSV-G)-pseudotyped lentivirus or MLV vectors carrying a green fluorescent protein marker gene. As predicted, the lentivirus vector was more efficient at transducing mouse and human growth-inhibited cell lines. The transduction of mouse HSC by lentivirus vectors was compared directly to MLV vectors in a co-transduction assay. In this assay, transduction by ecotropic MLV is a positive internal control for downstream steps in retrovirus transduction, including cell division. Both the VSV-G lentivirus and MLV vectors transduced mouse HSCs maintained in cytokine-free medium at very low frequency, as did the ecotropic control. The lentivirus vector and the MLV vector were equally efficient at transducing bone marrow HSCs cultured in interleukin 3 (IL-3), IL-6, and stem cell factor for 96 hours. In conclusion, although lentivirus vectors are able to transduce growth-inhibited cell lines, the cell cycle status of HSCs render them resistant to lentivirus-mediated transduction, and it is hypothesized that entry into cycle, not necessarily division, may be a requirement for efficient lentivirus-mediated transduction.
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Barrette, Stephane, Janet L. Douglas, Nancy E. Seidel, and David M. Bodine. "Lentivirus-based vectors transduce mouse hematopoietic stem cells with similar efficiency to Moloney murine leukemia virus–based vectors." Blood 96, no. 10 (November 15, 2000): 3385–91. http://dx.doi.org/10.1182/blood.v96.10.3385.h8003385_3385_3391.
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The low levels of transduction of human hematopoietic stem cells (HSCs) with Moloney murine leukemia virus (MLV) vectors have been an obstacle to gene therapy for hematopoietic diseases. It has been demonstrated that lentivirus vectors are more efficient than MLV vectors at transducing nondividing cell lines as well as human CD34+ cells and severe combined immunodeficiency disease repopulating cells. We compared transduction of cell lines and Lin− bone marrow cells, using a vesicular stomatitis virus G (VSV-G)-pseudotyped lentivirus or MLV vectors carrying a green fluorescent protein marker gene. As predicted, the lentivirus vector was more efficient at transducing mouse and human growth-inhibited cell lines. The transduction of mouse HSC by lentivirus vectors was compared directly to MLV vectors in a co-transduction assay. In this assay, transduction by ecotropic MLV is a positive internal control for downstream steps in retrovirus transduction, including cell division. Both the VSV-G lentivirus and MLV vectors transduced mouse HSCs maintained in cytokine-free medium at very low frequency, as did the ecotropic control. The lentivirus vector and the MLV vector were equally efficient at transducing bone marrow HSCs cultured in interleukin 3 (IL-3), IL-6, and stem cell factor for 96 hours. In conclusion, although lentivirus vectors are able to transduce growth-inhibited cell lines, the cell cycle status of HSCs render them resistant to lentivirus-mediated transduction, and it is hypothesized that entry into cycle, not necessarily division, may be a requirement for efficient lentivirus-mediated transduction.
12
De Angioletti, Maria, Ana Rovira, Michel Sadelain, Lucio Luzzatto, and Rosario Notaro. "Frequency of Missense Mutations in the Coding Region of a Eukaryotic Gene Transferred by Retroviral Vectors." Journal of Virology 76, no. 4 (February 15, 2002): 1991–94. http://dx.doi.org/10.1128/jvi.76.4.1991-1994.2002.
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ABSTRACT A relatively high mutation rate is probably a major factor in the evolutionary success of retroviruses, because it generates the genetic diversity that helps them to cope with changes in the environment. When using recombinant retroviruses as vectors for gene transfer and gene therapy, it is important to consider the implications of this biological characteristic. Until now, the mutation rate has been studied by using noneukaryotic genes as reporters. Here we report point mutations in the human glucose-6-phosphate dehydrogenase (hG6PD) gene transferred by Moloney murine leukemia virus-based vectors into murine bone marrow cells and NIH 3T3 murine fibroblasts. After bone marrow transplantation, we observed an hG6PD with abnormal electrophoretic mobility for 2 out of 34 mice. Next, we studied this phenomenon quantitatively and found 1 electrophoretically abnormal hG6PD variant among 93 independently isolated NIH 3T3 clones, from which we estimate a mutation rate of 1.4 × 10−5 per base pair per replication cycle. Mutations in the transferred gene can thus contribute to the impairment of the effectiveness of retrovirus-mediated gene transfer.
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Nishida, Yuki, Aya Maeda, Dhruv Chachad, Jo Ishizawa, Yi Hua Qiu, Steven M. Kornblau, Shinya Kimura, Michael Andreeff, and Kensuke Kojima. "Preclinical activity of the novel B‐cell‐specific Moloney murine leukemia virus integration site 1 inhibitor PTC ‐209 in acute myeloid leukemia: Implications for leukemia therapy." Cancer Science 106, no. 12 (November 20, 2015): 1705–13. http://dx.doi.org/10.1111/cas.12833.
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Tan, Peng H., Sven C. Beutelspacher, Shao-An Xue, Yao-He Wang, Peter Mitchell, James C. McAlister, D. Frank P. Larkin, et al. "Modulation of human dendritic-cell function following transduction with viral vectors: implications for gene therapy." Blood 105, no. 10 (May 15, 2005): 3824–32. http://dx.doi.org/10.1182/blood-2004-10-3880.
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AbstractGenetic modification of dendritic-cell (DC) function is an attractive approach to treat disease, either using mature DCs (mDCs) to immunize patients, or immature DCs (iDCs) to induce tolerance. Viral vectors are efficient at transducing DCs, and we have investigated the effect of transduction with a variety of viral vectors on the phenotype and function of DCs. Adenovirus (Ad), human immunodeficiency virus (HIV), equine anemia virus (EIAV), and Moloney murine leukemia virus (MMLV) all up-regulate costimulatory molecules and major histocompatibility complex (MHC) class II expression on DCs, as well as, in the case of Ad and lentiviral vectors, inducing production of Th1 and proinflammatory cytokines. Following transduction there is activation of double-stranded (ds) RNA-triggered pathways resulting in interferon (IFN) α/β production. In addition, the function of virally infected DCs is altered; iDCs have an increased, and mDCs a decreased, ability to stimulate a mixed lymphocyte reaction (MLR). Viral transduction of mDCs results in up-regulation of the indoleamine 2,3-dioxygenase (IDO) enzyme, which down-regulates T-cell responsiveness. Inhibition of IDO restores the ability of mDCs to stimulate an MLR, indicating that IDO is responsible for the modulation of mDC function. These data have important implications for the use of viral vectors in the transduction of DCs.
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Dardalhon, Valérie, Sara Jaleco, Cosette Rebouissou, Christophe Ferrand, Nadia Skander, Louise Swainson, Pierre Tiberghien, Hergen Spits, Nelly Noraz, and Naomi Taylor. "Highly efficient gene transfer in naive human T cells with a murine leukemia virus-based vector." Blood 96, no. 3 (August 1, 2000): 885–93. http://dx.doi.org/10.1182/blood.v96.3.885.
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Abstract Retroviral vectors based on the Moloney murine leukemia virus (MuLV) have become the primary tool for gene delivery into hematopoietic cells, but clinical trials have been hampered by low transduction efficiencies. Recently, we and others have shown that gene transfer of MuLV-based vectors into T cells can be significantly augmented using a fibronectin-facilitated protocol. Nevertheless, the relative abilities of naive (CD45RA+) and memory (CD45RO+) lymphocyte subsets to be transduced has not been assessed. Although naive T cells demonstrate a restricted cytokine profile following antigen stimulation and a decreased susceptibility to infection with human immunodeficiency virus, it was not clear whether they could be efficiently infected with a MuLV vector. This study describes conditions that permitted gene transfer of an enhanced green fluorescent protein-expressing retroviral vector in more than 50% of naive umbilical cord (UC) blood and peripheral blood (PB) T cells following CD3/CD28 ligation. Moreover, treatment of naive T cells with interleukin-7 resulted in the maintenance of a CD45RA phenotype and gene transfer levels approached 20%. Finally, it was determined that parameters for optimal transduction of CD45RA+ T cells isolated from PB and UC blood differed: transduction of the UC cells was significantly increased by the presence of autologous mononuclear cells (24.5% versus 56.5%). Because naive T cells harbor a receptor repertoire that allows them to respond to novel antigens, the development of protocols targeting their transduction is crucial for gene therapy applications. This approach will also allow the functions of exogenous genes to be evaluated in primary nontransformed naive T cells.
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Dardalhon, Valérie, Sara Jaleco, Cosette Rebouissou, Christophe Ferrand, Nadia Skander, Louise Swainson, Pierre Tiberghien, Hergen Spits, Nelly Noraz, and Naomi Taylor. "Highly efficient gene transfer in naive human T cells with a murine leukemia virus-based vector." Blood 96, no. 3 (August 1, 2000): 885–93. http://dx.doi.org/10.1182/blood.v96.3.885.015k22_885_893.
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Retroviral vectors based on the Moloney murine leukemia virus (MuLV) have become the primary tool for gene delivery into hematopoietic cells, but clinical trials have been hampered by low transduction efficiencies. Recently, we and others have shown that gene transfer of MuLV-based vectors into T cells can be significantly augmented using a fibronectin-facilitated protocol. Nevertheless, the relative abilities of naive (CD45RA+) and memory (CD45RO+) lymphocyte subsets to be transduced has not been assessed. Although naive T cells demonstrate a restricted cytokine profile following antigen stimulation and a decreased susceptibility to infection with human immunodeficiency virus, it was not clear whether they could be efficiently infected with a MuLV vector. This study describes conditions that permitted gene transfer of an enhanced green fluorescent protein-expressing retroviral vector in more than 50% of naive umbilical cord (UC) blood and peripheral blood (PB) T cells following CD3/CD28 ligation. Moreover, treatment of naive T cells with interleukin-7 resulted in the maintenance of a CD45RA phenotype and gene transfer levels approached 20%. Finally, it was determined that parameters for optimal transduction of CD45RA+ T cells isolated from PB and UC blood differed: transduction of the UC cells was significantly increased by the presence of autologous mononuclear cells (24.5% versus 56.5%). Because naive T cells harbor a receptor repertoire that allows them to respond to novel antigens, the development of protocols targeting their transduction is crucial for gene therapy applications. This approach will also allow the functions of exogenous genes to be evaluated in primary nontransformed naive T cells.
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Sung, Pamela J., Mayumi Sugita, Holly Koblish, Alexander E. Perl, and Martin Carroll. "Hematopoietic cytokines mediate resistance to targeted therapy in FLT3-ITD acute myeloid leukemia." Blood Advances 3, no. 7 (April 3, 2019): 1061–72. http://dx.doi.org/10.1182/bloodadvances.2018029850.
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Abstract Activating mutations in Fms-like tyrosine kinase 3 (FLT3) occur in ∼30% of adult cases of acute myeloid leukemia (AML). Selective second- and third-generation FLT3 inhibitors have shown significant clinical activity in patients with relapsed FLT3-mutant AML. However, clearance of FLT3-mutant clones does not consistently occur, and disease will progress in most patients after an initial response. This scenario challenges the model of FLT3-mutant AML being oncogene addicted, and it suggests that redundant signaling pathways regulate AML cell survival after FLT3 inhibition. We show that primary FLT3-mutant AML cells escape apoptosis induced by FLT3 inhibition in vitro in the presence of cytokines produced normally in the bone marrow, particularly granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-3 (IL-3). Despite reactivating canonical FLT3-signaling pathways, GM-CSF and IL-3 maintain cell survival without rescuing proliferation. Cytokine-mediated resistance through GM-CSF and IL-3 is dependent on JAK kinase, STAT5, and proviral integration site of Moloney murine leukemia virus (PIM) but not MAPK or mammalian target of rapamycin signaling. Cotreatment with FLT3 inhibitors and inhibitors of JAK or PIM kinases blocks GM-CSF and IL-3 rescue of cell survival in vitro and in vivo. Altogether, these data provide a strong rationale for combination therapy with FLT3 inhibitors to potentially improve clinical responses in AML.
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Paar, Matthias, Sonja Schwab, Doris Rosenfellner, Brian Salmons, Walter H. Günzburg, Matthias Renner, and Daniel Portsmouth. "Effects of Viral Strain, Transgene Position, and Target Cell Type on Replication Kinetics, Genomic Stability, and Transgene Expression of Replication-Competent Murine Leukemia Virus-Based Vectors." Journal of Virology 81, no. 13 (April 18, 2007): 6973–83. http://dx.doi.org/10.1128/jvi.02470-06.
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ABSTRACT The limited efficiency of in vivo gene transfer by replication-deficient retroviral vectors remains an obstacle to achieving effective gene therapy for solid tumors. One approach to circumvent this problem is the use of replication-competent retroviral vectors. However, the application of such vectors is at a comparatively early stage and the effects which virus strain, transgene cassette position, and target cell can exert on vector spread kinetics, genomic stability, and transgene expression levels remain to be fully elucidated. Thus, in this study a panel of vectors allowing the investigation of different design features on an otherwise genetically identical background were analyzed with respect to these readout parameters in cultures of both murine and human cells and in preformed tumors in nude mice. The obtained data revealed that (i) Moloney murine leukemia virus (Mo-MLV)-based vectors spread with faster kinetics, drive higher levels of transgene expression, and are more stable than equivalent Akv-MLV-based vectors; (ii) vectors containing the transgene cassette directly downstream of the envelope gene are genomically more stable than those containing it within the 3′-long terminal repeat U3 region; and (iii) the genomic stability of both strains seems to be cell line dependent.
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Crooks, GM, and DB Kohn. "Growth factors increase amphotropic retrovirus binding to human CD34+ bone marrow progenitor cells." Blood 82, no. 11 (December 1, 1993): 3290–97. http://dx.doi.org/10.1182/blood.v82.11.3290.3290.
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Abstract Gene transfer into human cells using murine amphotropic retroviral vectors is the basic technique used in most current gene therapy studies. The identity of the cell surface receptor for the amphotropic envelope remains unknown and thus its importance in gene transfer is poorly understood. We have measured specific retrovirus binding to cells to study amphotropic virus receptor regulation in human CD34+ bone marrow (BM) progenitors and primitive CD34+CD38- human hematopoietic cells. The rat monoclonal antibody 83A25 recognizes an epitope common to the envelope glycoprotein of all classes of Moloney murine leukemia virus. Indirect fluorescent labeling of 83A25 allows flow cytometric analysis of specific virus-cell interactions and is an indirect measure of specific receptors. Using this assay, amphotropic virus binding to fresh CD34+ cells was minimal. However, when CD34+ cells were cultured with or without growth factors for 4 days, specific binding of amphotropic retrovirus was readily shown. Inclusion of interleukin-3 (IL-3), IL-6, and Steel factor in cultures increased the fluorescence associated with amphotropic virus binding by twofold to four-fold (mean fold increase 2.7 +/- 0.84). Virus binding to CD34+CD38- cells was shown only in those cells culture in IL-3, IL-6, and Steel factor. These results suggest that certain cytokines may cause an increase in the number and/or affinity of amphotropic receptors on primitive human hematopoietic cells. Upregulation of viral receptor expression may be one of the mechanisms by which cytokines enhance gene transfer into primitive BM cells.
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Crooks, GM, and DB Kohn. "Growth factors increase amphotropic retrovirus binding to human CD34+ bone marrow progenitor cells." Blood 82, no. 11 (December 1, 1993): 3290–97. http://dx.doi.org/10.1182/blood.v82.11.3290.bloodjournal82113290.
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Gene transfer into human cells using murine amphotropic retroviral vectors is the basic technique used in most current gene therapy studies. The identity of the cell surface receptor for the amphotropic envelope remains unknown and thus its importance in gene transfer is poorly understood. We have measured specific retrovirus binding to cells to study amphotropic virus receptor regulation in human CD34+ bone marrow (BM) progenitors and primitive CD34+CD38- human hematopoietic cells. The rat monoclonal antibody 83A25 recognizes an epitope common to the envelope glycoprotein of all classes of Moloney murine leukemia virus. Indirect fluorescent labeling of 83A25 allows flow cytometric analysis of specific virus-cell interactions and is an indirect measure of specific receptors. Using this assay, amphotropic virus binding to fresh CD34+ cells was minimal. However, when CD34+ cells were cultured with or without growth factors for 4 days, specific binding of amphotropic retrovirus was readily shown. Inclusion of interleukin-3 (IL-3), IL-6, and Steel factor in cultures increased the fluorescence associated with amphotropic virus binding by twofold to four-fold (mean fold increase 2.7 +/- 0.84). Virus binding to CD34+CD38- cells was shown only in those cells culture in IL-3, IL-6, and Steel factor. These results suggest that certain cytokines may cause an increase in the number and/or affinity of amphotropic receptors on primitive human hematopoietic cells. Upregulation of viral receptor expression may be one of the mechanisms by which cytokines enhance gene transfer into primitive BM cells.
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Oliveira, Hugo V. C., Spartaco Astolfi-Filho, and Edmar V. Andrade. "Constructing a DNAzyme Delivery and Expression System for Escherichia coli: A Prototype for Phage Therapy." European Journal of Biology and Biotechnology 2, no. 2 (March 18, 2021): 19–25. http://dx.doi.org/10.24018/ejbio.2021.2.2.158.
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Antisense oligonucleotides exhibit high potential for use as therapeutic agents. '10-23' DNAzymes are antisense molecules with a high chemical stability and catalytic efficiency. In the present study, we developed a phagemid containing a DNAzyme expression system regulated by two promoters. One of these promoters, pA1, promotes constitutive expression of Moloney murine leukemia virus reverse transcriptase (MoMuLV-RT). The other promoter, plac, regulates transcription of the RNA substrate from which MoMuLV-RT produces the DNAzyme by reverse transcription. The ftsZ DNAzyme was used to validate this expression system in the phagemid, named pDESCP. ftsZ DNAzyme expression altered the morphological pattern of Escherichia coli from a bacillary to filamentous form. In E. coli FtsZ is the primary component of the cell division apparatus, forming a structure known as Z-ring, which is the place of division. It is suggested that the DNAzyme ftsZ is decreasing the translation of this protein. Delivery of pDESCP into F+ strain of E. coli cells, using VCSM13, and the possible insertion of other DNAzymes into the cassette makes this phagemid an important prototype for phage therapy.
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Lothrop, CD Jr, ZS al-Lebban, GP Niemeyer, JB Jones, MG Peterson, JR Smith, HJ Baker, RA Morgan, MA Eglitis, and WF Anderson. "Expression of a foreign gene in cats reconstituted with retroviral vector infected autologous bone marrow." Blood 78, no. 1 (July 1, 1991): 237–45. http://dx.doi.org/10.1182/blood.v78.1.237.237.
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Abstract A Moloney murine leukemia virus based retroviral vector was used to transfer the bacterial neomycin resistance gene (neoR) into feline hematopoietic cells. We reconstituted four cats that had been lethally irradiated with autologous bone marrow that had been infected with the N2 or SAX retroviral vector. Bone marrow cells from all four cats expressed the neoR gene 30 days posttransplant and three of four cats still had the neoR gene and a low level of drug resistant colony- forming unit granulocyte-macrophage after more than 200 days. Two of the four cats unexpectedly developed diabetes mellitus 90 days posttransplantation. The expression of a foreign gene in cats, albeit at a low level, demonstrates that retroviral vectors can be used for gene transfer in noninbred large animal species and may be useful for gene therapy of humans. The development of diabetes mellitus in two of the subjects emphasizes the value of animal models for the study of possible deleterious effects of retroviral vector-mediated gene transfer.
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Lothrop, CD Jr, ZS al-Lebban, GP Niemeyer, JB Jones, MG Peterson, JR Smith, HJ Baker, RA Morgan, MA Eglitis, and WF Anderson. "Expression of a foreign gene in cats reconstituted with retroviral vector infected autologous bone marrow." Blood 78, no. 1 (July 1, 1991): 237–45. http://dx.doi.org/10.1182/blood.v78.1.237.bloodjournal781237.
Full textAbstract:
A Moloney murine leukemia virus based retroviral vector was used to transfer the bacterial neomycin resistance gene (neoR) into feline hematopoietic cells. We reconstituted four cats that had been lethally irradiated with autologous bone marrow that had been infected with the N2 or SAX retroviral vector. Bone marrow cells from all four cats expressed the neoR gene 30 days posttransplant and three of four cats still had the neoR gene and a low level of drug resistant colony- forming unit granulocyte-macrophage after more than 200 days. Two of the four cats unexpectedly developed diabetes mellitus 90 days posttransplantation. The expression of a foreign gene in cats, albeit at a low level, demonstrates that retroviral vectors can be used for gene transfer in noninbred large animal species and may be useful for gene therapy of humans. The development of diabetes mellitus in two of the subjects emphasizes the value of animal models for the study of possible deleterious effects of retroviral vector-mediated gene transfer.
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Takamiya, Yoshiaki, M. Priscilla Short, Frederick L. Moolten, Christina Fleet, Toshihiro Mineta, Xandra O. Breakefield, and Robert L. Martuza. "An experimental model of retrovirus gene therapy for malignant brain tumors." Journal of Neurosurgery 79, no. 1 (July 1993): 104–10. http://dx.doi.org/10.3171/jns.1993.79.1.0104.
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✓ Recent research using rodent models of central nervous system gliomas indicates that a combination of gene transfer and drug treatment may be successful in killing tumor cells. In the present study, a mouse fibroblast-derived packaging cell line, psi 2, which releases a replication-defective retrovirus vector bearing the herpes simplex virus type 1 (HSV)-thymidine kinase (TK) gene, was grown with rat C6 tumor cells in the presence and absence of wild type Moloney murine leukemia virus (MoMLV). Consequently, tumor cells became sensitive to ganciclovir, which is selectively converted to a toxic nucleotide analog by HSV-TK. This killing effect was more effective in the presence than in the absence of wild type retrovirus both in culture and in subcutaneous tumors in nude mice. Tumors regressed in vivo and failed to regrow over a subsequent 10-day observation period after combined treatment with packaging cells, wild type MoMLV, and ganciclovir. This killing effect may be augmented by the ability of the helper retrovirus to package the vector in tumor cells and thus extend delivery of the HSV-TK gene to more tumor cells. This represents significant improvement in tumor therapy in this model system as compared with helper-free systems previously reported by the authors and others. Although additional improvements in the therapy can be envisioned, this approach may prove useful in combination with current modes of therapy for these insidious and lethal tumors.
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Gough, Peter J., and Elaine W. Raines. "Gene therapy of apolipoprotein E–deficient mice using a novel macrophage-specific retroviral vector." Blood 101, no. 2 (January 15, 2003): 485–91. http://dx.doi.org/10.1182/blood-2002-07-2131.
Full textAbstract:
The use of retroviral gene transfer into hematopoietic stem cells for human gene therapy has been hampered by the absence of retroviral vectors that can generate long-lasting, lineage-specific gene expression. We developed self-inactivating retroviral vectors that incorporate gene-regulatory elements from the macrophage-restricted human CD68 gene. Through the transplantation of transduced murine hematopoietic stem cells (HSCs), we show that a vector incorporating a 342–base pair (bp) fragment of 5′ flanking sequence from the CD68 gene, in addition to the CD68 first intron, was able to direct macrophage-specific expression of an enhanced green fluorescent protein (EGFP) reporter gene in inflammatory cell exudates and lymphoid organs in vivo. Levels of EGFP expression generated by this vector were greater than those generated by a standard Moloney murine leukemia retroviral vector, and they were stable for at least a year after transplantation of transduced HSCs. To evaluate the ability of this vector to generate therapeutically useful levels of gene expression, we transplanted apolipoprotein E (ApoE)–deficient HSCs transduced with a virus encoding ApoE into ApoE-deficient mice. Macrophages from these mice expressed levels of ApoE that were comparable to those from wild-type mice, and vector-driven expression of ApoE in macrophages was sufficient to reverse both hypercholesterolemia and atherosclerotic lesion development. The future application of this retroviral vector should provide a powerful tool to further elucidate macrophage function and for human gene therapy.
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Verhasselt, Bruno, Magda De Smedt, Rita Verhelst, Evelien Naessens, and Jean Plum. "Retrovirally Transduced CD34++ Human Cord Blood Cells Generate T Cells Expressing High Levels of the Retroviral Encoded Green Fluorescent Protein Marker In Vitro." Blood 91, no. 2 (January 15, 1998): 431–40. http://dx.doi.org/10.1182/blood.v91.2.431.
Full textAbstract:
Abstract Human umbilical cord blood (UCB) hematopoietic stem cells (HSC) receive increased attention as a possible target for gene-transfer in gene therapy trials. Diseases affecting the lymphoid lineage, as adenosine deaminase (ADA) deficiency and acquired immunodeficiency syndrome (AIDS) could be cured by gene therapy. However, the T-cell progenitor potential of these HSC after gene-transfer is largely unknown and was up to now not testable in vitro. We show here that highly purified CD34++ Lineage marker-negative (CD34++Lin−) UCB cells generate T, natural killer (NK), and dendritic cells in a severe combined immunodeficient mouse fetal thymus organ culture (FTOC). CD34++Lin− and CD34++CD38−Lin− UCB cells express the retroviral encoded marker gene Green Fluorescent Protein (GFP) after in vitro transduction with MFG-GFP retroviral supernatant. Transduced cells were still capable of generating T, NK, and dendritic cells in the FTOC, all expressing high levels of GFP under control of the Moloney murine leukemia virus (MoMuLV) long terminal repeat promotor. We thus present an in vitro assay for thymic T-cell development out of transduced UCB HSC, using GFP as a marker gene.
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Verhasselt, Bruno, Magda De Smedt, Rita Verhelst, Evelien Naessens, and Jean Plum. "Retrovirally Transduced CD34++ Human Cord Blood Cells Generate T Cells Expressing High Levels of the Retroviral Encoded Green Fluorescent Protein Marker In Vitro." Blood 91, no. 2 (January 15, 1998): 431–40. http://dx.doi.org/10.1182/blood.v91.2.431.431_431_440.
Full textAbstract:
Human umbilical cord blood (UCB) hematopoietic stem cells (HSC) receive increased attention as a possible target for gene-transfer in gene therapy trials. Diseases affecting the lymphoid lineage, as adenosine deaminase (ADA) deficiency and acquired immunodeficiency syndrome (AIDS) could be cured by gene therapy. However, the T-cell progenitor potential of these HSC after gene-transfer is largely unknown and was up to now not testable in vitro. We show here that highly purified CD34++ Lineage marker-negative (CD34++Lin−) UCB cells generate T, natural killer (NK), and dendritic cells in a severe combined immunodeficient mouse fetal thymus organ culture (FTOC). CD34++Lin− and CD34++CD38−Lin− UCB cells express the retroviral encoded marker gene Green Fluorescent Protein (GFP) after in vitro transduction with MFG-GFP retroviral supernatant. Transduced cells were still capable of generating T, NK, and dendritic cells in the FTOC, all expressing high levels of GFP under control of the Moloney murine leukemia virus (MoMuLV) long terminal repeat promotor. We thus present an in vitro assay for thymic T-cell development out of transduced UCB HSC, using GFP as a marker gene.
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Kung, Sam K. P., Dong Sung An, and Irvin S. Y. Chen. "A Murine Leukemia Virus (MuLV) Long Terminal Repeat Derived from Rhesus Macaques in the Context of a Lentivirus Vector and MuLVgag Sequence Results in High-Level Gene Expression in Human T Lymphocytes." Journal of Virology 74, no. 8 (April 15, 2000): 3668–81. http://dx.doi.org/10.1128/jvi.74.8.3668-3681.2000.
Full textAbstract:
ABSTRACT We constructed human immunodeficiency virus type 1 (HIV-1) vectors that will allow higher levels of gene expression in T cells. Gene expression under the control of an internal cytomegalovirus (CMV) immediate-early promoter in a self-inactivating lentiviral vector (CSCG) is 4- to 15-fold lower in T-cell lines (SUPT1 and CEMX174) than in non-lymphoid-cell lines (HeLa and 293T). This is in contrast to a Moloney murine leukemia virus (MoMLV)-based retrovirus vector (SRαLEGFP). We therefore replaced the internal CMV promoter of CSCG with three different murine oncoretroviral long terminal repeat (LTR) promoters—murine sarcoma virus (MSV), MoMLV (MLV), and the LTR (termed Rh-MLV) that is derived from the ampho-mink cell focus-forming (AMP/MCF) retrovirus in the serum of one rhesus macaque monkey that developed T-cell lymphoma following autologous transplantation of enriched bone marrow stem cells transduced with a retrovirus vector preparation containing replication-competent viruses (E. F. Vanin, M. Kaloss, C. Broscius, and A. W. Nienhuis, J. Virol. 68:4241–4250, 1994). We found that the combination of Rh-MLV LTR and a partial gag sequence of MoMLV (Δgag 871–1612) in CS-Rh-MLV-E gave the highest level of enhanced green fluorescent protein (EGFP) gene expression compared with MLV, MSV LTR, phosphoglycerate kinase, and CMV promoters in T-cell lines, as well as activated primary T cells. Interestingly, there was a further two- to threefold increase in EGFP expression (thus, 10-fold-higher expression than with CMV) when the Rh-MLV promoter and Δgag 871–1612 were used in a self-inactivating-vector setting that has a further deletion in the U3 region of the HIV-1 LTR. These hybrid vectors should prove useful in gene therapy applications for T cells.
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Wu, Chengxiang, and Yuanan Lu. "High-titre retroviral vector system for efficient gene delivery into human and mouse cells of haematopoietic and lymphocytic lineages." Journal of General Virology 91, no. 8 (August 1, 2010): 1909–18. http://dx.doi.org/10.1099/vir.0.020255-0.
Full textAbstract:
Genetically modified cells of haematopoietic and lymphocytic lineages could provide potentially curative treatments for a wide range of inherited and acquired diseases. However, this application is limited in mouse models by the low efficiency of lentiviral vectors. To facilitate the rapid production of high-titre helper-free retroviral vectors for enhanced gene delivery, multiple modifications to a prototype moloney murine leukemia virus (MoMLV)-derived vector system were made including adaptation of the vector system to simian virus 40 ori/T antigen-mediated episomal replication in packaging cells, replacement of the MoMLV 5′ U3 promoter with a series of stronger composite promoters and addition of an extra polyadenylation signal downstream of the 3′ long terminal repeat. These modifications enhanced vector production by 2–3 logs. High-titre vector stocks were tested for their ability to infect a variety of cells derived from humans and mice, including primary monocyte-derived macrophage cultures. Whilst the lentiviral vector was significantly restricted at the integration level, the MoMLV-based vector showed effective gene transduction of mouse cells. This high-titre retroviral vector system represents a useful tool for efficient gene delivery into human and mouse haematopoietic and lymphocytic cells, with particular application in mice as a small animal model for novel gene therapy tests.
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Puglia, Jennifer, Tan Wang, Christine Smith-Snyder, Marie Cote, Michael Scher, Joelle N. Pelletier, Sinu John, Colleen B. Jonsson, and Monica J. Roth. "Revealing Domain Structure through Linker-Scanning Analysis of the Murine Leukemia Virus (MuLV) RNase H and MuLV and Human Immunodeficiency Virus Type 1 Integrase Proteins." Journal of Virology 80, no. 19 (October 1, 2006): 9497–510. http://dx.doi.org/10.1128/jvi.00856-06.
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ABSTRACT Linker-scanning libraries were generated within the 3′ terminus of the Moloney murine leukemia virus (M-MuLV) pol gene encoding the connection-RNase H domains of reverse transcriptase (RT) as well as the structurally related M-MuLV and human immunodeficiency virus type 1 (HIV-1) integrase (IN) proteins. Mutations within the M-MuLV proviral vectors were Tn7 based and resulted in 15-bp insertions. Mutations within an HIV-1 IN bacterial expression vector were based on Tn5 and resulted in 57-bp insertions. The effects of the insertions were examined in vivo (M-MuLV) and in vitro (HIV-1). A total of 178 individual M-MuLV constructs were analyzed; 40 in-frame insertions within RT connection-RNase H, 108 in-frame insertions within IN, 13 insertions encoding stop codons within RNase H, and 17 insertions encoding stop codons within IN. For HIV-1 IN, 56 mutants were analyzed. In both M-MuLV and HIV-1 IN, regions are identified which functionally tolerate multiple-linker insertions. For MuLV, these correspond to the RT-IN proteolytic junction, the junction between the IN core and C terminus, and the C terminus of IN. For HIV-1 IN, in addition to the junction between the IN core and C terminus and the C terminus of IN, insertions between the N terminus and core domains maintained integration and disintegration activity. Of the 40 in-frame insertions within the M-MuLV RT connection-RNase H domains, only the three C-terminal insertions mapping to the RT-IN proteolytic junction were viable. These results correlate with deletion studies mapping the domain and subdomain boundaries of RT and IN. Importantly, these genetic footprints provide a means to identify nonessential regions within RT and IN for targeted gene therapy applications.
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Correll, PH, S. Colilla, HP Dave, and S. Karlsson. "High levels of human glucocerebrosidase activity in macrophages of long- term reconstituted mice after retroviral infection of hematopoietic stem cells." Blood 80, no. 2 (July 15, 1992): 331–36. http://dx.doi.org/10.1182/blood.v80.2.331.331.
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Abstract Gaucher disease is a leading candidate for somatic gene therapy using bone marrow (BM) cells as target tissue. Towards this end, we have constructed a retroviral vector (LG) in which the human glucocerebrosidase (GC) cDNA is driven by the Moloney murine leukemia virus (MoMLV) long terminal repeat (LTR). Day 12 to 14 colony-forming unit-spleen progenitor cells were infected by the LG virus with a 100% efficiency, and GC messenger RNA (mRNA) and protein were detected in the progeny of these cells. Tissues from long-term reconstituted mice analyzed 8 months posttransplantation with LG-infected BM contained the intact provirus at greater than 1 copy per cell, indicating effective infection of hematopoietic stem cells. Human GC mRNA generated by the viral LTR was detected in macrophages as well as other hematopoietic cells. Enzyme activity was increased fivefold and twofold in macrophages from BM and spleen, respectively, and could be precipitated with an antibody specific for human GC. Immunohistochemical analysis detected the human GC protein in 81% of the macrophages from five recipient mice. These data indicate that, after transduction of hematopoietic stem cells, the LG vector is capable of directing expression of human GC in the majority of macrophages from long-term reconstituted mice and producing enzyme levels comparable with endogenous mouse activity, suggesting that this virus may be useful in the treatment of Gaucher disease.
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Correll, PH, S. Colilla, HP Dave, and S. Karlsson. "High levels of human glucocerebrosidase activity in macrophages of long- term reconstituted mice after retroviral infection of hematopoietic stem cells." Blood 80, no. 2 (July 15, 1992): 331–36. http://dx.doi.org/10.1182/blood.v80.2.331.bloodjournal802331.
Full textAbstract:
Gaucher disease is a leading candidate for somatic gene therapy using bone marrow (BM) cells as target tissue. Towards this end, we have constructed a retroviral vector (LG) in which the human glucocerebrosidase (GC) cDNA is driven by the Moloney murine leukemia virus (MoMLV) long terminal repeat (LTR). Day 12 to 14 colony-forming unit-spleen progenitor cells were infected by the LG virus with a 100% efficiency, and GC messenger RNA (mRNA) and protein were detected in the progeny of these cells. Tissues from long-term reconstituted mice analyzed 8 months posttransplantation with LG-infected BM contained the intact provirus at greater than 1 copy per cell, indicating effective infection of hematopoietic stem cells. Human GC mRNA generated by the viral LTR was detected in macrophages as well as other hematopoietic cells. Enzyme activity was increased fivefold and twofold in macrophages from BM and spleen, respectively, and could be precipitated with an antibody specific for human GC. Immunohistochemical analysis detected the human GC protein in 81% of the macrophages from five recipient mice. These data indicate that, after transduction of hematopoietic stem cells, the LG vector is capable of directing expression of human GC in the majority of macrophages from long-term reconstituted mice and producing enzyme levels comparable with endogenous mouse activity, suggesting that this virus may be useful in the treatment of Gaucher disease.
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Liu, Liqiong, Ling Liu, W. French Anderson, Robert W. Beart, Erlinda M. Gordon, and Frederick L. Hall. "Incorporation of Tumor Vasculature Targeting Motifs into Moloney Murine Leukemia Virus Env Escort Proteins Enhances Retrovirus Binding and Transduction of Human Endothelial Cells." Journal of Virology 74, no. 11 (June 1, 2000): 5320–28. http://dx.doi.org/10.1128/jvi.74.11.5320-5328.2000.
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ABSTRACT Adhesion receptors expressed on the surfaces of tumor-activated endothelial cells provide an advantageous locus for targeting gene therapy vectors to angiogenic tissues and/or tumor vasculature. In this study, we engineered a series of Asn-Gly-Arg (NGR)-containing congeners of the presumptive cell binding motif contained within the ninth type III repeat of fibronectin and displayed these tumor vasculature targeting motifs (TVTMs) within the context of Moloney murine leukemia envelope “escort” proteins. Comparative studies of envelope incorporation into viral particles and evaluation of the cell binding properties of the targeted vectors revealed critical structural features, thus identifying a subset of optimal TVTMs. Utilizing a modified ELISA to evaluate viral binding to target cells, we observed a significant down-regulation of TVTM-virion binding to human endothelial cells following sustained (48-h) exposure to VEGF. Normalized for equivalent titers (106 CFU/ml), as assayed on NIH 3T3 cells, vectors displaying TVTM escort proteins significantly enhanced the transduction efficiency from 12.2 to 37.4% in human KSY-1 endothelial cell cultures (P < 0.001) and from 0.4 to 4.1% in human umbilical vein endothelial cell (HUVEC) cultures (P < 0.001). In summary, these studies utilized an engineering approach to identify a subset of TVTMs that are stably incorporated as envelope “escort” proteins into retroviral vectors and that, by functioning to improve the binding efficiency and transduction of both HUVEC and KSY1 endothelial cells, may have therapeutic potential for targeting gene delivery to the tumor-associated vasculature.
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Yates, Frank, Michèle Malassis-Séris, Daniel Stockholm, Cécile Bouneaud, Frédérique Larousserie, Patricia Noguiez-Hellin, Olivier Danos, et al. "Gene therapy of RAG-2−/− mice: sustained correction of the immunodeficiency." Blood 100, no. 12 (December 1, 2002): 3942–49. http://dx.doi.org/10.1182/blood-2002-03-0782.
Full textAbstract:
Patients with mutations of either RAG-1 or RAG-2 genes suffer from severe combined immunodeficiency (SCID) characterized by the lack of T and B lymphocytes. The only curative treatment today consists of hematopoietic stem cell (HSC) transplantation, which is only partially successful in the absence of an HLA genoidentical donor, thus justifying research to find an alternative therapeutic approach. To this end, RAG-2–deficient mice were used to test whether retrovirally mediated ex vivo gene transfer into HSCs could provide long-term correction of the immunologic deficiency. Murine RAG-2−/−Sca-1+ selected bone marrow cells were transduced with a modified Moloney leukemia virus (MLV)–based MND (myeloproliferative sarcoma virus enhancer, negative control region deleted, dl587rev primer-binding site substituted) retroviral vector containing the RAG-2 cDNA and transplanted into RAG-2−/− sublethally irradiated mice (3Gy). Two months later, T- and B-cell development was achieved in all mice. Diverse repertoire of T cells as well as proliferative capacity in the presence of mitogens, allogeneic cells, and keyhole limpet hemocyanin (KLH) were shown. B-cell function as shown by serum Ig levels and antibody response to a challenge by KLH also developed. Lymphoid subsets and function were shown to be stable over a one-year period without evidence of any detectable toxicity. Noteworthy, a selective advantage for transduced lymphoid cells was evidenced by comparative provirus quantification in lymphoid and myeloid lineages. Altogether, this study demonstrates the efficiency of ex vivo RAG-2 gene transfer in HSCs to correct the immune deficiency of RAG-2−/− mice, constituting a significant step toward clinical application.
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Cattoglio, Claudia, Danilo Pellin, Ermanno Rizzi, Giulietta Maruggi, Giorgio Corti, Francesca Miselli, Daniela Sartori, et al. "High-definition mapping of retroviral integration sites identifies active regulatory elements in human multipotent hematopoietic progenitors." Blood 116, no. 25 (December 16, 2010): 5507–17. http://dx.doi.org/10.1182/blood-2010-05-283523.
Full textAbstract:
Abstract Integration of retroviral vectors in the human genome follows nonrandom patterns that favor insertional deregulation of gene expression and increase the risk of their use in clinical gene therapy. The molecular basis of retroviral target site selection is still poorly understood. We used deep sequencing technology to build genomewide, high-definition maps of > 60 000 integration sites of Moloney murine leukemia virus (MLV)– and HIV-based retroviral vectors in the genome of human CD34+ multipotent hematopoietic progenitor cells (HPCs) and used gene expression profiling, chromatin immunoprecipitation, and bioinformatics to associate integration to genetic and epigenetic features of the HPC genome. Clusters of recurrent MLV integrations identify regulatory elements (alternative promoters, enhancers, evolutionarily conserved noncoding regions) within or around protein-coding genes and microRNAs with crucial functions in HPC growth and differentiation, bearing epigenetic marks of active or poised transcription (H3K4me1, H3K4me2, H3K4me3, H3K9Ac, Pol II) and specialized chromatin configurations (H2A.Z). Overall, we mapped 3500 high-frequency integration clusters, which represent a new resource for the identification of transcriptionally active regulatory elements. High-definition MLV integration maps provide a rational basis for predicting genotoxic risks in gene therapy and a new tool for genomewide identification of promoters and regulatory elements controlling hematopoietic stem and progenitor cell functions.
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Veres, Gabor, Uwe Junker, Jenny Baker, Carmen Barske, Creton Kalfoglou, Heini Ilves, Sonia Escaich, Hideto Kaneshima, and Ernst Böhnlein. "Comparative Analyses of Intracellularly Expressed Antisense RNAs as Inhibitors of Human Immunodeficiency Virus Type 1 Replication." Journal of Virology 72, no. 3 (March 1, 1998): 1894–901. http://dx.doi.org/10.1128/jvi.72.3.1894-1901.1998.
Full textAbstract:
ABSTRACT The antiviral activities of intracellularly expressed antisense RNAs complementary to the human immunodeficiency virus type 1 (HIV-1) pol, vif, and env genes and the 3′ long terminal repeat (LTR) sequence were evaluated in this comparative study. Retroviral vectors expressing the antisense RNAs as part of the Moloney murine leukemia virus LTR promoter-directed retroviral transcript were constructed. The CD4+ T-cell line CEM-SS was transduced with retroviral constructs, and Northern blot analyses showed high steady-state antisense RNA expression levels. The most efficient inhibition of HIV-1 replication was observed with theenv antisense RNA, followed by the polcomplementary sequence, leading to 2- to 3-log10 reductions in p24 antigen production even at high inoculation doses (4 × 104 50% tissue culture infective doses) of the HIV-1 strain HXB3. The strong antiviral effect correlated with a reduction of HIV-1 steady-state RNA levels, and with intracellular Tat protein production, suggesting that antisense transcripts act at an early step of HIV-1 replication. A lower steady-state antisense RNA level was detected in transduced primary CD4+ lymphocytes than in CEM-SS cells. Nevertheless, replication of the HIV-1 JR-CSF isolate was reduced with both the pol and envantisense RNA. Intracellularly expressed antisense sequences demonstrated more pronounced antiviral efficacy than thetrans-dominant RevM10 protein, making these antisense RNAs a promising gene therapy strategy for HIV-1.
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Mardiney, Michael, Sharon H. Jackson, S. Kaye Spratt, Fei Li, Steven M. Holland, and Harry L. Malech. "Enhanced Host Defense After Gene Transfer in the Murine p47phox-Deficient Model of Chronic Granulomatous Disease." Blood 89, no. 7 (April 1, 1997): 2268–75. http://dx.doi.org/10.1182/blood.v89.7.2268.
Full textAbstract:
Abstract The p47phox−/− mouse exhibits a phenotype similar to that of human chronic granulomatous disease (CGD) and, thus, is an excellent model for the study of gene transfer technology. Using the Moloney murine leukemia virus–based retroviral vector MFG-S encoding the human form of p47phox, we performed ex vivo gene transfer into Sca-1+ p47phox−/− marrow progenitor cells without conditioning of donors with 5-fluorouracil. Transduced progenitors were transplanted into moderately irradiated (500 cGy), G-CSF preconditioned sibling p47phox−/− mice. Using the fluorescent probe dihydrorhodamine 123 (DHR), in vivo biochemical correction of the superoxide-generating NADPH oxidase system was detected by flow cytometry in 12.3% ± 0.9% of phorbol myristate acetate–stimulated peripheral blood neutrophils at 4 weeks and 2.6% ± 1.0% at 14 weeks after transplantation. Following gene therapy, mice were challenged with the CGD pathogen Burkholderia (formerly Pseudomonas) cepacia and bacteremia levels were assessed at 24 hours and 7 days after inoculation. At both time points, bacteremia levels in gene corrected p47phox−/− mice were significantly lower than untreated p47phox−/− mice (0.89 ± 0.30 colonies v 237.7 ± 83.6 colonies at 24 hours, P < .02; 4.0 ± 2.0 colonies v 110.2 ± 26.5 colonies at 7 days, P < .0014). More importantly, Kaplan-Meier survival analysis showed a significant survival advantage of gene corrected versus untreated p47phox−/− mice (P < .001). Thus, stem-cell–directed ex vivo gene therapy is capable of restoring phagocyte oxidant-dependent host-defense function in this mouse model of a human immune-system disorder.
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Whitwam, Todd, Mark E. Haskins, Paula S. Henthorn, Jennifer N. Kraszewski, Sandra E. Kleiman, Nancy E. Seidel, David M. Bodine, and Jennifer M. Puck. "Retroviral Marking of Canine Bone Marrow: Long-Term, High-Level Expression of Human Interleukin-2 Receptor Common Gamma Chain in Canine Lymphocytes." Blood 92, no. 5 (September 1, 1998): 1565–75. http://dx.doi.org/10.1182/blood.v92.5.1565.
Full textAbstract:
Abstract Optimization of retroviral gene transfer into hematopoietic cells of the dog will facilitate gene therapy of canine X-linked severe combined immunodeficiency (XSCID) and in turn advance similar efforts to treat human XSCID. Both canine and human XSCID are caused by defects in the common γ chain, γc, of receptors for interleukin-2 and other cytokines. In this study, normal dogs were given retrovirally transduced bone marrow cells with and without preharvest mobilization by the canine growth factors granulocyte colony-stimulating factor (G-CSF) and stem cell factor (SCF). Harvey sarcoma virus and Moloney murine leukemia virus constructs were used, both containing cDNA encoding human γc. The Harvey-based vector transduced into cytokine-primed marrow yielded persistent detectable provirus in bone marrow and blood and expression of human γc on peripheral lymphocytes. In three dogs, human γc expression disappeared after 19 to 34 weeks but reappeared and was sustained, in one dog beyond 16 months posttransplantation, upon immunosuppression with cyclosporin A and prednisone, with up to 25% of lymphocytes expressing human γc. The long-term expression of human γc in a high proportion of normal canine lymphocytes predicts that retrovirus-mediated gene correction of hematopoietic cells may prove to be of clinical benefit in humans affected with this XSCID. This is a US government work. There are no restrictions on its use.
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Whitwam, Todd, Mark E. Haskins, Paula S. Henthorn, Jennifer N. Kraszewski, Sandra E. Kleiman, Nancy E. Seidel, David M. Bodine, and Jennifer M. Puck. "Retroviral Marking of Canine Bone Marrow: Long-Term, High-Level Expression of Human Interleukin-2 Receptor Common Gamma Chain in Canine Lymphocytes." Blood 92, no. 5 (September 1, 1998): 1565–75. http://dx.doi.org/10.1182/blood.v92.5.1565.417k12_1565_1575.
Full textAbstract:
Optimization of retroviral gene transfer into hematopoietic cells of the dog will facilitate gene therapy of canine X-linked severe combined immunodeficiency (XSCID) and in turn advance similar efforts to treat human XSCID. Both canine and human XSCID are caused by defects in the common γ chain, γc, of receptors for interleukin-2 and other cytokines. In this study, normal dogs were given retrovirally transduced bone marrow cells with and without preharvest mobilization by the canine growth factors granulocyte colony-stimulating factor (G-CSF) and stem cell factor (SCF). Harvey sarcoma virus and Moloney murine leukemia virus constructs were used, both containing cDNA encoding human γc. The Harvey-based vector transduced into cytokine-primed marrow yielded persistent detectable provirus in bone marrow and blood and expression of human γc on peripheral lymphocytes. In three dogs, human γc expression disappeared after 19 to 34 weeks but reappeared and was sustained, in one dog beyond 16 months posttransplantation, upon immunosuppression with cyclosporin A and prednisone, with up to 25% of lymphocytes expressing human γc. The long-term expression of human γc in a high proportion of normal canine lymphocytes predicts that retrovirus-mediated gene correction of hematopoietic cells may prove to be of clinical benefit in humans affected with this XSCID. This is a US government work. There are no restrictions on its use.
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Donahue, R. E., S. W. Kessler, D. Bodine, K. McDonagh, C. Dunbar, S. Goodman, B. Agricola, E. Byrne, M. Raffeld, and R. Moen. "Helper virus induced T cell lymphoma in nonhuman primates after retroviral mediated gene transfer." Journal of Experimental Medicine 176, no. 4 (October 1, 1992): 1125–35. http://dx.doi.org/10.1084/jem.176.4.1125.
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Moloney Murine Leukemia Virus (MoMuLV) causes T cell neoplasms in rodents but is not known to be a pathogen in primates. The core protein and enzyme genes of the MoMuLV genome together with an amphotropic envelope gene are utilized to engineer the cell lines that generate retroviral vectors for use in current human gene therapy applications. We developed a producer clone that generates a very high concentration of retroviral vector particles to optimize conditions for gene insertion into pluripotent hematopoietic stem cells. This producer cell line also generates a much lower concentration of replication-competent virus that arose through recombination. Stem cells from rhesus monkeys were purified by immunoselection with an anti-CD34 antibody, incubated in vitro for 80-86 h in the presence of retroviral vector particles with accompanying replication-competent virus and used to reconstitute recipients whose bone marrow had been ablated by total body irradiation. The retroviral vector genome was detected in circulating cells of five of eight transplant recipients of CD34+ cells and in the circulating cells of two recipients of infected, unfractionated bone marrow mononuclear cells. Three recipients of CD34+ cells had a productive infection with replication-competent virus. Six or seven mo after transplantation, each of these animals developed a rapidly progressive T cell neoplasm involving the thymus, lymph nodes, liver, spleen, and bone marrow. Lymphoma cells contained 10-50 copies of the replication-competent virus, but lacked the retroviral vector genome. We conclude that replication-competent viruses arising from producer cells making retroviral vectors can be pathogenic in primates, which underscores the importance of carefully screening retroviral producer clones used in human trials to exclude contamination with replication-competent virus.
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Xu, Lingfei, Cuihua Gao, Mark S. Sands, Shi-Rong Cai, Timothy C. Nichols, Dwight A. Bellinger, Robin A. Raymer, Stephanie McCorquodale, and Katherine Parker Ponder. "Neonatal or hepatocyte growth factor–potentiated adult gene therapy with a retroviral vector results in therapeutic levels of canine factor IX for hemophilia B." Blood 101, no. 10 (May 15, 2003): 3924–32. http://dx.doi.org/10.1182/blood-2002-10-3050.
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AbstractHemophilia B is a bleeding disorder resulting from factor IX (FIX) deficiency that might be treated with gene therapy. Neonatal delivery would correct the disease sooner than would transfer into adults, and could reduce immunological responses. Neonatal mice were injected intravenously with a Moloney murine leukemia virus–based retroviral vector (RV) expressing canine FIX (cFIX). They achieved 150% to 280% of normal cFIX antigen levels in plasma (100% is 5 μg/mL), which was functional in vitro and in vivo. Three newborn hemophilia B dogs that were injected intravenously with RV achieved 12% to 36% of normal cFIX antigen levels, which improved coagulation tests. Only one mild bleed has occurred during 14 total months of evaluation. This is the first demonstration of prolonged expression after neonatal gene therapy for hemophilia B in mice or dogs. Most animals failed to make antibodies to cFIX, demonstrating that neonatal gene transfer may induce tolerance. Although hepatocytes from newborns replicate, those from adults do not. Adult mice therefore received hepatocyte growth factor to induce hepatocyte replication prior to intravenous injection of RV. This resulted in expression of 35% of normal cFIX antigen levels for 11 months, although all mice produced anti-cFIX antibodies. This is the first demonstration that high levels of FIX activity can be achieved with an RV in adults without a partial hepatectomy to induce hepatocyte replication. We conclude that RV-mediated hepatic gene therapy is effective for treating hemophilia B in mice and dogs, although the immune system may complicate gene transfer in adults.
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Lagresle-Peyrou, Chantal, Frank Yates, Michele Malassis-Seris, Christophe Hue, Estelle Morillon, Alexandrine Garrigue, Allen Liu, et al. "Retroviral Gene Therapy of RAG-1-/- Mice: Balance between Efficiency and Toxicity." Blood 106, no. 11 (November 16, 2005): 460. http://dx.doi.org/10.1182/blood.v106.11.460.460.
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Abstract Patients affected by severe combined immunodeficiency (SCID) have a profound defect in T cell development and the only curative treatment is hematopoietic stem cell transplantation (HSCT). When an HLA-identical family related donor exists, the success rate of HSCT is 90% while in all others cases, it ranges between 40 and 70%. In SCID patients also presenting B cell differentiation defects, such as in RAG-1 and RAG-2 deficiencies, the survival rate is significantly reduced. We have thus been interested in the development of a potential alternative treatment by using retroviral gene transfer of a normal copy of RAG-1 cDNA. To this end, murine RAG-1 deficient hematopoietic stem cells were transduced with a retroviral modified Moloney leukemia virus vector containing the RAG-1cDNA and transplanted into RAG-1-deficient mice. B and T cell development was achieved in all the recipient mice and the reconstitution is stable over time, attesting for a selective advantage of transduced progenitors. The T cell compartment was found to be diverse and functional as shown by Va and Vb TCR immunoscope analysis as well as proliferation assays in the presence of mitogens. The mature circulating B lymphocytes were not abundant but functional as the serum immunoglobulin levels and specific antibody response against the T cell dependent KLH antigen were always within normal range. Noteworthy, a high transgene copy number was detected in all lymphoid organs and this was associated with a risk of insertional mutagenesis as observed in one mouse. Altogether, these results demonstrate that RAG-1 gene transfer can correct immunodeficiency associated with RAG-1 defect but that human application would require the use of lentivirus vectors with self inactivating long terminal repeats in order to decrease the risk of lymphoproliferative diseases.
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Phelan, James D., Cyrus Khandanpour, Shane Horman, Marie-Claude Gaudreau, Jinfang Zhu, William E. Paul, Ulrich Dührsen, H. Leighton Grimes, and Tarik Moroy. "Growth Factor Independent-1 (Gfi1) Is Critically Required for T-Cell Acute Lymphoblastic Leukemia (T-ALL) Tumor Initiation and Maintenance." Blood 116, no. 21 (November 19, 2010): 3156. http://dx.doi.org/10.1182/blood.v116.21.3156.3156.
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Abstract Abstract 3156 T cell acute lymphoblastic leukemia (T-ALL) is one of the most common childhood cancers associated with mutations in NOTCH1. The Growth factor independent-1 (Gfi1) transcriptional repressor gene was originally discovered as a common target of Moloney murine leukemia virus (MMLV) proviral insertion in murine T-ALL. In fact, the Gfi1 locus is the most frequently activated gene in MMLV-induced T cell leukemia. Therefore, we investigated whether the most commonly activated gene in MMLV-induced murine T-ALL, Gfi1, could collaborate with the most commonly activated gene in human T-ALL, NOTCH1. Here, we show that GFI1 expression is associated with Notch signaling in human T-ALL (p'0.0003). Functionally, Gfi1 collaborates with Notch-induced murine T-ALL by accelerating an already rapid disease model (p=0.03) without altering the lymphoblastic nature of the disease. Furthermore, inducible deletion of Gfi1 is counter-selected in both Notch-driven retroviral and transgenic mouse models of T-ALL; whereas, constitutive absence of Gfi1 completely prevents transgenic Notch-induced T-ALL (p≤0.04). However, T-ALL tumors can form in Gfi1-/- animals using either ENU-mutagenesis or MMLV-infection, yet tumor formation is delayed (p≤0.02, p≤0.03 respectively). This suggests that Gfi1 deletion does not prevent the formation of the T-ALL initiating cell and that Gfi1 might be absolutely required for Notch-induced T-ALL. Most striking is that Gfi1 is required for T-ALL maintenance in vitro and in vivo. Using three separate Tal1-initiated murine T-ALL cell lines, the overexpression of the Gfi1 dominant-negative, Gfi1N382S, was quickly and completely counter-selected. As Gfi1 has previously been found to regulate pro-apoptotic genes in T cells, we attempted to rescue the above loss of function phenotype by overexpressing the anti-apoptotic factor Bcl2. Notably, counter-selection of Gfi1N382 is not observed or is significantly delayed in all three cell lines. In vivo, inducible deletion of Gfi1 leads to both mutagen- or Notch-induced tumor regression as measured by ultrasound. In fact, levels of Gfi1 expression directly correlate to tumor regression and disease free survival of T-ALL. Finally, targeting Gfi1 enhances the efficacy of radiation therapy and bone marrow transplantation. Deletion of Gfi1 sensitizes T-ALL tumors and T cells to p53-dependent apoptosis after exposure to DNA-damaging agents such as radiation, Etoposide or Daunorubicin by de-repression of the pro-apoptotic Gfi1 target gene Bax. These data extend the role of Gfi1 to human T-ALL and suggest that T-ALL is dependent upon Gfi1 to repress pro-apoptotic genes for tumor survival, ultimately highlighting a new therapeutic target in the fight against lymphoid malignancies. Disclosures: No relevant conflicts of interest to declare.
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Segura, María Mercedes, Alain Garnier, Marcos Rafael Di Falco, Gavin Whissell, Angélica Meneses-Acosta, Normand Arcand, and Amine Kamen. "Identification of Host Proteins Associated with Retroviral Vector Particles by Proteomic Analysis of Highly Purified Vector Preparations." Journal of Virology 82, no. 3 (November 21, 2007): 1107–17. http://dx.doi.org/10.1128/jvi.01909-07.
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ABSTRACT The Moloney murine leukemia virus (MMLV) belongs to the Retroviridae family of enveloped viruses, which is known to acquire minute amounts of host cellular proteins both on the surface and inside the virion. Despite the extensive use of retroviral vectors in experimental and clinical applications, the repertoire of host proteins incorporated into MMLV vector particles remains unexplored. We report here the identification of host proteins from highly purified retroviral vector preparations obtained by rate-zonal ultracentrifugation. Viral proteins were fractionated by one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis, in-gel tryptic digested, and subjected to liquid chromatography/tandem mass spectrometry analysis. Immunogold electron microscopy studies confirmed the presence of several host membrane proteins exposed at the vector surface. These studies led to the identification of 27 host proteins on MMLV vector particles derived from 293 HEK cells, including 5 proteins previously described as part of wild-type MMLV. Nineteen host proteins identified corresponded to intracellular proteins. A total of eight host membrane proteins were identified, including cell adhesion proteins integrin β1 (fibronectin receptor subunit beta) and HMFG-E8, tetraspanins CD81 and CD9, and late endosomal markers CD63 and Lamp-2. Identification of membrane proteins on the retroviral surface is particularly attractive, since they can serve as anchoring sites for the insertion of tags for targeting or purification purposes. The implications of our findings for retrovirus-mediated gene therapy are discussed.
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Hammer, Markus H., Grit Schröder, Kirsten Risch, Alexander Flügel, Hans-Dieter Volk, Manfred Lehmann, and Thomas Ritter. "Antigen-Dependent Transgene Expression in Kidney Transplantation: A Novel Approach Using Gene-Engineered T Lymphocytes." Journal of the American Society of Nephrology 13, no. 2 (February 2002): 511–18. http://dx.doi.org/10.1681/asn.v132511.
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ABSTRACT. So far, gene therapy in transplantation mainly focuses on the expression of therapeutic proteins in the graft itself. Insufficient transfection and inflammatory responses that are due to the immunogenicity of multiple vector systems are often limiting factors in these approaches. The potential of genetically modified T lymphocytes was investigated as a delivery system for therapeutic transgenes to transplanted organs as a way to circumvent immunogenicity and efficiency problems in a rat transplant model. Gene-engineering of alloantigen-specific rat T cell lines was performed by using a Moloney murine leukemia virus (MoMuLV)–based enhanced green fluorescence protein (EGFP) encoding retroviral transduction system. The ex vivo gene-modified lymphocytes were adoptively transferred into syngeneic rats carrying allogeneic, syngeneic, or third party kidneys. Homing behavior, activation level, and transgene expression of the adoptively given cells were monitored. The TEGFP lymphocytes infiltrated the transplanted kidneys in an antigen-specific manner. High numbers of alloantigen-specific T lymphocytes accumulated exclusively in allografts but not in syngeneic or third party grafts. Flow cytometric analysis revealed that only TEGFP lymphocytes found in allografts had an activated phenotype that resulted in higher transgene expression. Alloantigen-specific homing, activation, and transgene expression are important prerequisites for the guarantee of localized delivery and expression of transgenic proteins by gene-engineered T lymphocytes. Antigen-specific gene-targeting strategies using ex vivo modified T lymphocytes with donor specificity are a novel approach to the delivery of therapeutic transgenes in transplantation.
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Li, Jian, Yunchao Wang, Jiayun Ge, Wenhua Li, Liangyu Yin, Zhiping Zhao, Songsong Liu, et al. "Doublecortin-Like Kinase 1 (DCLK1) Regulates B Cell-Specific Moloney Murine Leukemia Virus Insertion Site 1 (Bmi-1) and is Associated with Metastasis and Prognosis in Pancreatic Cancer." Cellular Physiology and Biochemistry 51, no. 1 (2018): 262–77. http://dx.doi.org/10.1159/000495228.
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Background/Aims: Cancer stem cells (CSCs) are largely responsible for tumor relapse and metastatic behavior. Doublecortin-like kinase 1 (DCLK1) was recently reported to be a biomarker for gastrointestinal CSCs and involved in the epithelial-mesenchymal transition (EMT) and tumor progression. B cell-specific Moloney murine leukemia virus insertion site 1 (Bmi-1) is a crucial regulator of CSC self-renewal, malignant transformation and EMT, and a previous study from our group showed that Bmi-1 is upregulated in pancreatic cancer progression and participates in EMT. However, it remains unclear whether DCLK1 is involved in pancreatic cancer or whether DCLK1 is associated with the altered level of Bmi-1 expression. Methods: The correlation of DCLK1 expression and clinical features of pancreatic cancer was analyzed in 210 paraffin-embedded archived pancreatic cancer specimens by immunohistochemical analysis. The biological effects of DCLK1 siRNA on cells were investigated by examining cell proliferation using a cell counting kit and cell colony assays, cell migration by wound healing assay and cell invasion by Transwell invasion assay. We further investigated the effect of therapeutic siRNA targeting DCLK1 on pancreatic cancer cell growth in vivo. Moreover, the molecular mechanism by which DCLK1 upregulates Bmi-1 expression was explored using real-time PCR, western blotting and Co-immunoprecipitation assay. Results: DCLK1 is overexpressed in pancreatic cancer and is related to metastasis and prognosis. Knockdown of DCLK1 markedly suppressed cell growth in vitro and in vivo and also inhibited the migration and invasion of pancreatic cancer cells. Furthermore, we found that DCLK1 silencing could inhibit EMT in cancer cells via downregulation of Bmi-1 and the mesenchymal markers Snail and Vimentin and upregulation of the epithelial marker E-cadherin. Moreover, high DCLK1 expression in human pancreatic cancer samples was associated with a mesenchymal phenotype and increased cell proliferation. Further co-immunoprecipitation indicated that DCLK1 did not interact with Bmi-1 directly. Conclusion: Our data suggest that upregulation of DCLK1 may contribute to pancreatic cancer metastasis and poor prognosis by increasing Bmi-1 expression indirectly. The findings indicate that inhibiting DCLK1 expression might be a novel strategy for pancreatic cancer therapy.
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Khandanpour, Cyrus, James D. Phelan, Riyan Chen, Shane Horman, Lothar Vassen, Marie-Claude Gaudreau, Joseph Krongold, et al. "Growth Factor Independent-1 (Gfi1) As a New Target for Human Leukemia Therapy." Blood 118, no. 21 (November 18, 2011): 560. http://dx.doi.org/10.1182/blood.v118.21.560.560.
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Abstract Abstract 560 More than 50% of patients diagnosed with B or T-cell leukemia and lymphoma will fail current treatment protocols. This highlights the urgent need for new and improved therapies. Since the transcription factor Growth factor independent-1 (Gfi1) plays an important role in lymphoid differentiation, we explored whether it might be a suitable target for therapy. Using mouse models in which T-cell leukemia can be induced by transgenic expression of mutated forms of Notch1, by injection of the carcinogen N-Ethyl–nitrosourea (ENU) or infection with a Murine Moloney Leukemia Virus, we found that Gfi1 knockout mice had a significantly lower incidence and a longer latency period of T-ALL. To verify whether targeting Gfi1 would be a novel approach to treat B- or T-cell lymphoma, we used Mx1Cre Gfi1fl/fl mice. In these mice, injection of polyinosinic-polycytidylic acid (pIpC) activates the Mx1 promoter driven Cre expression, which ultimately leads to the deletion of the floxed Gfi1 alleles. As controls, we used Gfi1fl/fl mice, which lack the Cre recombinase and thus still express Gfi1 after pIpC injection. To elicit a T- or B-cell lymphoma, we used ENU injection combined with expression of a mutated Notch1 transgene for T-ALL, or transgenic over-expression of c-Myc for B-cell leukemia (Eμ-Myc). Using in-vivo ultrasound supported imaging, we observed complete regression of tumour masses when Gfi1 was eliminated in Mx1Cre Gfi1fl/fl mice, curing the mice of the either the T or B-cell malignancies. Strikingly, this effect was observed in the absence of any other treatment regimen. To explore the mechanisms underlying this phenomenon, we explanted tumor samples from mice, in which Gfi1 expression was either maintained or deleted and performed gene expression arrays. A comparative analysis of the array data demonstrated that loss of Gfi1 affects pathways of key importance for leukemia such as metabolism, cell cycle progression, basal transcription and apoptosis but also the response to DNA damage. It has been shown previously for non hematological malignancies that oncogenic transformation in conjuction with dysregulated cell cycle induces DNA strand breaks (DSBs), which leads to an increased p53 dependent apoptotic response in tumours compared to non-transformed cells. This forces the tumor cells to counteract this effect – for instance by selection for the loss of p53. Consistent with this concept, we noted that leukemic cells from our tumor models displayed a greater amount of DSBs and also higher rates of spontaneous apoptosis than normal cells. Interestingly, the number of apoptotic cells was further increased in those tumors where Gfi1 had been deleted. We hypothesized that Gfi1 protects leukemia cells against DSB induced apoptosis. To test this hypothesis, we irradiated in Gfi1+/+ and Gfi1−/− thymocytes, which induces DSB in thymocytes. In line with our hypothesis we found that Gfi1−/− thymocytes showed increased rates of apoptosis compared to irradiated Gfi1+/+ thymocytes and that loss of Gfi1 led to an increased induction of pro-apoptotic genes such as Bax, Noxa and Puma after irradiation. Since Bax, Noxa and Puma are all p53 target genes, we investigated a possible link between Gfi1 and p53 and found that (I) Gfi1 binds to p53, (II) that Gfi1 inhibits the transcription of p53 target genes and (III) that Gfi1 occupies p53 target gene at the same sites as p53. In summary, Gfi1 antagonizes p53 function and loss of Gfi1 sensitizes cells to p53-mediated apoptosis. Next, we used different human T-ALL cell lines and treated these cells either with sh-RNA lentivirus or morpholinos to abrogate GFI1 expression. In all cases, down-regulation of GFI1 expression led to increased apoptosis and impeded growth of human leukemia cells. Finally, we transplanted leukemic cells of T-ALL patients into NOD-Scid, IL2Rnull (NSG) mice, waited for the leukemic cells to engraft, and then injected GFI1 specific- or control morpholinos. While mice treated with control morpholino died of leukemia, the animals treated with GFI1-specific morpholinos survived showing a significant reduction of human leukemic cells in the blood, bone marrow and spleen, even with samples from patients who did not respond to first line therapy. Since morpholinos have received approval for use in humans, our data suggest that targeting GFI1 in human T-ALL patients may be a promising therapeutic target and a feasible way to complement current T-ALL treatment regimens. Disclosures: No relevant conflicts of interest to declare.
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Malik, P., WJ Krall, XJ Yu, C. Zhou, and DB Kohn. "Retroviral-mediated gene expression in human myelomonocytic cells: a comparison of hematopoietic cell promoters to viral promoters." Blood 86, no. 8 (October 15, 1995): 2993–3005. http://dx.doi.org/10.1182/blood.v86.8.2993.2993.
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Abstract Gene transfer into human hematopoietic stem cells with expression targeted to the maturing myelomonocytic progeny has applications for gene therapy of genetic diseases affecting granulocytes and macrophages. We hypothesized that promoters of myeloid-specific genes that are upregulated with myelomonocytic differentiation would also upregulate expression of an exogenous gene in a retroviral vector. Moloney murine leukemia virus (MoMuLV)-based retroviral vectors using promoters from hematopoietic genes (CD11b, CD18, and CD34) were compared with vectors with viral promoters (MoMuLV long terminal repeat [LTR], cytomegalovirus [CMV], and simian virus 40 [SV40]). Human glucocerebrosidase (GC) cDNA was the reporter gene. HL60 cells were transduced with these vectors and vector-derived GC activity was compared in undifferentiated HL-60 cells and the same cells differentiated into granulocytes using dimethyl sulfoxide or monocyte/macrophages using phorbol myristate acetate. In undifferentiated HL-60 cells, vector-derived GC activity was the highest when it was controlled by the MoMuLV LTR. In HL-60 cells differentiated into granulocytes, vector-derived GC activity transcribed from the CD11b, MoMuLV LTR, and CMV promoters was equivalent to 1.7, 1.5, and 1.5 times the normal endogenous GC activity, respectively, and 0.8, 2.0, and 3.6 times the normal GC activity, respectively, in those differentiated into macrophages. With granulocytic differentiation, the CD11b promoter showed maximal induction in GC activity (8-fold); with macrophage differentiation, the CD11b promoter showed a fourfold induction in GC expression. The CD11b promoter also generated significant levels of GC activity in the myelomonocytic progeny of transduced CD34+ cells. Expression from the CD11b promoter, unlike that from the CMV or the MoMuLV LTR promoters, was relatively myelomonocyte-specific, with minimal expression observed in Jurkat T cells or HeLa carcinoma cells. The induction of expression from the CD11b promoter with differentiation in HL-60 cells correlates with the developmental regulation of the CD11b gene. Retroviral vectors using the CD11b promoter have potential utility for gene therapy of disorders affecting the myelomonocytic lineage.
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Malik, P., WJ Krall, XJ Yu, C. Zhou, and DB Kohn. "Retroviral-mediated gene expression in human myelomonocytic cells: a comparison of hematopoietic cell promoters to viral promoters." Blood 86, no. 8 (October 15, 1995): 2993–3005. http://dx.doi.org/10.1182/blood.v86.8.2993.bloodjournal8682993.
Full textAbstract:
Gene transfer into human hematopoietic stem cells with expression targeted to the maturing myelomonocytic progeny has applications for gene therapy of genetic diseases affecting granulocytes and macrophages. We hypothesized that promoters of myeloid-specific genes that are upregulated with myelomonocytic differentiation would also upregulate expression of an exogenous gene in a retroviral vector. Moloney murine leukemia virus (MoMuLV)-based retroviral vectors using promoters from hematopoietic genes (CD11b, CD18, and CD34) were compared with vectors with viral promoters (MoMuLV long terminal repeat [LTR], cytomegalovirus [CMV], and simian virus 40 [SV40]). Human glucocerebrosidase (GC) cDNA was the reporter gene. HL60 cells were transduced with these vectors and vector-derived GC activity was compared in undifferentiated HL-60 cells and the same cells differentiated into granulocytes using dimethyl sulfoxide or monocyte/macrophages using phorbol myristate acetate. In undifferentiated HL-60 cells, vector-derived GC activity was the highest when it was controlled by the MoMuLV LTR. In HL-60 cells differentiated into granulocytes, vector-derived GC activity transcribed from the CD11b, MoMuLV LTR, and CMV promoters was equivalent to 1.7, 1.5, and 1.5 times the normal endogenous GC activity, respectively, and 0.8, 2.0, and 3.6 times the normal GC activity, respectively, in those differentiated into macrophages. With granulocytic differentiation, the CD11b promoter showed maximal induction in GC activity (8-fold); with macrophage differentiation, the CD11b promoter showed a fourfold induction in GC expression. The CD11b promoter also generated significant levels of GC activity in the myelomonocytic progeny of transduced CD34+ cells. Expression from the CD11b promoter, unlike that from the CMV or the MoMuLV LTR promoters, was relatively myelomonocyte-specific, with minimal expression observed in Jurkat T cells or HeLa carcinoma cells. The induction of expression from the CD11b promoter with differentiation in HL-60 cells correlates with the developmental regulation of the CD11b gene. Retroviral vectors using the CD11b promoter have potential utility for gene therapy of disorders affecting the myelomonocytic lineage.
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Kurre, Peter, Ponni Anandakumar, Michael A. Harkey, and Hans-Peter Kiem. "Multi-Copy Integration after HIV-Derived Lentivirus Vector Transduction of Murine Hematopoietic Stem Cells Does Not Promote Clonal Proliferation in Primary or Secondary Recipients." Blood 104, no. 11 (November 16, 2004): 2105. http://dx.doi.org/10.1182/blood.v104.11.2105.2105.
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Abstract Replication competent Moloney murine leukemia virus (MLV) retrovirus is used experimentally in murine models to identify potential oncogenes by repeat infection and resultant insertion of multiple proviral copies into the target cell genome. Mutagenicity in this system relies on proviral insertion in proximity of oncogenes, or their regulatory sequences leading to subsequent activation and clonal expansion. Replication incompetent MLV-derived vector particles are attractive vehicles for gene therapy strategies, and have been shown to retain these mutagenic properties after transduction of highly enriched murine and human hematopoietic progenitor and stem cells. Work by others suggests that this may in part occur in a vector particle dose and copy number dependent, transgene independent fashion (Modlich et al., Blood 2003 Suppl., abstract 699; Brugman et al., Molecular Therapy 2004 Suppl., abstract 1046). It is unclear if the same properties of mutagenic potential and copy number dependence apply to the insertion of HIV-derived lentivirus vectors. To address this question we have used VSV-G pseudotyped lentiviral vector (VSV-G/RRLsin-cPPThPGK-EGFPwpre) particles to transduce non-enriched mouse hematopoietic stem cells at escalating vector particle concentrations for subsequent repopulation of myeloablated murine recipients. Cells were transduced in culture with a single round of infection at a multiplicity of 1, 3, 10, or 30 in the presence of multiple cytokines and fibronectin fragment. Recipient animals readily reconstituted their hematopoietic system and demonstrated GFP marking in myeloid, B- and T- lymphoid cells. Peripheral blood counts, kinetics of GFP marking and flow-cytometric light scatter profiles showed no evidence of clonal proliferation. Primary recipients (n=23) were sacrificed between 5 and 7 months from transplantation to examine their marrow, peripheral blood and (in part) spleen for proviral marking by flow cytometry and real-time PCR. Results show a predicted increase in average proviral copy number ranging from 1.8 (range 1.2 – 2.8) after low MOI (1) infection to 17.5 (range 2.9 – 46.8) after high MOI (30) infection. Further, PCR amplification of genomic-proviral junction sites from progenitor colonies obtained at sacrifice of primary recipients showed no evidence of clonal restriction in the cohort of animals with an average of 7.9 proviral copies per GFP-marked cell (MOI 10 cohort). Secondary recipients (n=71) in all dose groups were followed for gene marking and, to date, have shown no signs of vector-driven clonal evolution. Our results suggest that HIV-derived lentivirus vector does not appear to have the same mutagenic properties at similar genomic copy numbers that others report for MLV-derived vectors in a comparable murine model system. This observation is consistent with distinct genomic insertion site preferences reported for HIV-derived vectors. We herein propose that, based on these and other advantageous features, lentivirus vectors are ideally suited for further pre-clinical and clinical exploration.