101
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Ellis J. Silencing and Variegation of Gammaretrovirus and Lentivirus Vectors. Hum Gene Ther 2005. [DOI: 10.1089/hum.2005.16.ft-126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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102
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Dalle B, Rubin JE, Alkan O, Sukonnik T, Pasceri P, Yao S, Pawliuk R, Leboulch P, Ellis J. eGFP reporter genes silence LCRbeta-globin transgene expression via CpG dinucleotides. Mol Ther 2005; 11:591-9. [PMID: 15771961 DOI: 10.1016/j.ymthe.2004.11.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2004] [Accepted: 11/15/2004] [Indexed: 10/26/2022] Open
Abstract
beta-Globin transgenes regulated by the locus control region (LCR) are dominantly silenced by linked bacterial reporter genes in transgenic mice. Enhanced green fluorescent protein (eGFP) from jellyfish is an alternative reporter used in retrovirus vectors to transfer LCRbeta-globin genes into bone marrow. We show here that the eGFP coding sequence silences LCRbeta-globin in transgenic mice, but the PGK promoter did not provoke such silencing. As eGFP contains 60 CpG dinucleotides, which are targets of DNA methylation, we synthesized a novel CpG-free variant called dmGFP. Its utility was demonstrated in MSCV retrovirus vectors transcriptionally controlled by the viral 5'LTR or internal PGK or EF1alpha promoter. Specific fluorescence was detected from eGFP, and at lower levels from dmGFP, in transduced mouse CFU-S and embryonic stem cells. While eGFP was rarely silenced in CFU-S, dmGFP was not silenced in these progenitors. Moreover, the dmGFP coding sequence did not silence LCRbeta-globin in transgenic mice, showing that the eGFP silencing mechanism acts primarily via CpG dinucleotides. However, LCRbeta-globin expression remained suboptimal, indicating that other silencing pathways recognize dmGFP in the absence of CpG dinucleotides. We conclude that dmGFP ameliorates silencing, but optimal LCRbeta-globin expression is obtained in the absence of nonmammalian reporters.
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Affiliation(s)
- Bruno Dalle
- Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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103
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Abstract
The hemoglobin disorders of beta-thalassemia and sickle cell disease together constitute the most prevalent group of human monogenic diseases. Although curative allogeneic stem cell transplantation therapy and palliative therapies have been developed for these disorders, the majority of patients still suffer significant morbidity and early mortality. The development of therapeutic approaches based on genetic manipulation of autologous stem cells therefore remains an attractive alternative. In the past 4 years, significant advances have been made toward this goal using lentiviral vectors to obtain high-level expression of complex globin gene cassettes. Therapeutic correction in murine models of both beta-thalassemia and sickle cell anemia has been achieved using this approach. These advances, coupled with progress in the ability to achieve in vivo selection of genetically modified cells, can now be evaluated in the well-developed nonhuman primate autologous transplant model. The goal in these studies is to provide preclinical safety and efficacy data prior to human clinical trials in order to maximize the likelihood of success in the context of an acceptable risk to benefit ratio. Here we review progress in each of these areas.
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Affiliation(s)
- Derek A Persons
- Department of Hematology/Oncology, Division of Experimental Hematology, St. Jude Children's Research Hospital, Memphis, TN, USA.
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104
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Sadelain M. Globin gene transfer as a potential treatment for the beta-thalassaemias and sickle cell disease. Vox Sang 2005; 87 Suppl 2:235-42. [PMID: 15209924 DOI: 10.1111/j.1741-6892.2004.00495.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- M Sadelain
- Laboratory of Gene Transfer and Gene Expression, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.
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105
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Mohamedali A, Moreau-Gaudry F, Richard E, Xia P, Nolta J, Malik P. Self-inactivating lentiviral vectors resist proviral methylation but do not confer position-independent expression in hematopoietic stem cells. Mol Ther 2005; 10:249-59. [PMID: 15294172 DOI: 10.1016/j.ymthe.2004.05.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2003] [Accepted: 05/02/2004] [Indexed: 11/18/2022] Open
Abstract
Oncoretroviral expression is transcriptionally silenced in embryonic and hematopoietic stem cells (HSCs). This is associated with methylation of viral and internal promoters. We determined whether self-inactivating (SIN) lentiviral vectors (LV) would circumvent proviral silencing in HSCs. We studied long-term expression, methylation, and position effects (PE) from two GFP-encoding SIN-LV containing erythroid enhancers and the human ankyrin-1 promoter (h-Ank-P) using the murine secondary bone marrow (BM) transplant assay. Proviral expression was detected in RBC 6-11 months following transplant only in 28 of 49 secondary mice, with 0.9 +/- 0.2 copy/cell and oligoclonally integrated provirus in BM, spleen, and thymus. Twenty-one of 49 secondary mice lacked integrated provirus. Secondary mice containing provirus also had GFP-expressing RBCs, although proviral copy number did not always correlate with expression, suggesting either proviral methylation or chromatin PE. The endogenous h-Ank-P was partially methylated in nonerythroid cell lines and unmethylated in erythroid cell lines. However, h-Ank-P in the provirus was unmethylated in erythroid and nonerythroid cells within secondary murine BM. Despite lack of methylation, GFP expression was variable in secondary BFU-e and in single-copy mouse erythroleukemia cell clones. Taken together, these data show that erythroid-specific SIN-LV express long term and resist methylation-associated proviral silencing, but may require additional elements to confer position-independent expression.
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Affiliation(s)
- Azim Mohamedali
- Division of Hematology-Oncology, Children's Hospital Los Angeles and University of Southern California Keck School of Medicine, 90027, USA
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106
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Zielske SP, Lingas KT, Li Y, Gerson SL. Limited lentiviral transgene expression with increasing copy number in an MGMT selection model: lack of copy number selection by drug treatment. Mol Ther 2005; 9:923-31. [PMID: 15194059 DOI: 10.1016/j.ymthe.2004.02.017] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2004] [Accepted: 02/23/2004] [Indexed: 12/31/2022] Open
Abstract
Retroviral vector integration into the human genome carries increased risk of oncogenesis with increasing integrations. To boost transgene expression for gene therapy, multiple integrations are often sought. We studied the relationship between the number of vector integrations and transgene expression and the effect that drug selection in an MGMT-selection model would have on vector copy number. K562 cells were transduced using a lentiviral vector and a library of clones was generated. Median proviral copy number was 4 and a positive correlation with transgene expression was observed. Transgene expression increased at a linear rate between 1 and 4 vector copies/cell, but was unpredictable at >4 integrations/cell. When lentivirus MGMT(P140K)-transduced K562 cells were treated with O(6)-benzylguanine (BG)/BCNU, there was no selection for increased median copy number in colony-forming units, despite strong selection pressure and an increase in transgene expression and activity. These data show a direct and linear correlation between MGMT(P140K) transgene expression and vector copy number. Strong BG/BCNU selective pressure does not result in preferential survival of high-copy-number clones but does select for strong transgene expression. Thus drug selection would not be expected to increase the risk of oncogenesis due to exaggerated selection in favor of high-copy-number vector integration.
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Affiliation(s)
- Steven P Zielske
- Division of Hematology/Oncology, Case Comprehensive Cancer Center and Center for Stem Cell and Regenerative Medicine, Case School of Medicine, Case Western Reserve University and University Hospitals of Cleveland, Cleveland, OH 44106, USA
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107
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Malik P, Arumugam PI. Gene Therapy for beta-thalassemia. HEMATOLOGY. AMERICAN SOCIETY OF HEMATOLOGY. EDUCATION PROGRAM 2005:45-50. [PMID: 16304358 DOI: 10.1182/asheducation-2005.1.45] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Gene transfer for beta-thalassemia requires gene transfer into hematopoietic stem cells using integrating vectors that direct regulated expression of beta globin at therapeutic levels. Among integrating vectors, oncoretroviral vectors carrying the human beta-globin gene and portions of the locus control region (LCR) have suffered from problems of vector instability, low titers and variable expression. In recent studies, human immunodeficiency virus-based lentiviral (LV) vectors were shown to stably transmit the human beta-globin gene and a large LCR element, resulting in correction of beta-thalassemia intermedia in mice. Several groups have since demonstrated correction of the mouse thalassemia intermedia phenotype, with variable levels of beta-globin expression. These levels of expression were insufficient to fully correct the anemia in thalassemia major mouse model. Insertion of a chicken hypersensitive site-4 chicken insulator element (cHS4) in self-inactivating (SIN) LV vectors resulted in higher and less variable expression of human beta-globin, similar to the observations with cHS4-containing retroviral vectors carrying the human gamma-globin gene. The levels of beta-globin expression achieved from insulated SIN-LV vectors were sufficient to phenotypically correct the thalassemia phenotype from 4 patients with human thalassemia major in vitro, and this correction persisted long term for up to 4 months, in xeno-transplanted mice in vivo. In summary, LV vectors have paved the way for clinical gene therapy trials for Cooley's anemia and other beta-globin disorders. SIN-LV vectors address several safety concerns of randomly integrating viral vectors by removing viral transcriptional elements and providing lineage-restricted expression. Flanking the proviral cassette with chromatin insulator elements, which additionally have enhancer-blocking properties, may further improve SIN-LV vector safety.
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Affiliation(s)
- Punam Malik
- Children's Hospital Los Angeles, 4650 Sunset Blvd., M.S. #45, Los Angeles, CA 90027, USA.
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108
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Abstract
AbstractHLA-identical sibling hematopoietic cell transplantation (HCT) for sickle cell disease (SCD) has a strong track record of efficacy and there is growing appreciation that its benefits exceed its risks in selected individuals. In contrast, the clinical utility of replacement gene therapy for sickle cell disease remains unproven. Its challenge is to ensure viral transduction into hematopoietic stem cells (HSCs) and to generate safe, stable, erythroid-specific replacement gene expression at a level that is sufficient to have a clinical effect. The clinical necessity for fulfilling all these criteria may make this genetic disorder among the most complex to treat successfully by gene therapy. But the experience of HCT for SCD has proven that eliminating the βS-globin gene is curative when the transfer is stable. Thus replacement gene therapy for sickle cell disease remains a subject of intense interest and investigation.
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Affiliation(s)
- Mark C Walters
- Children's Hospital and Research Center - Oakland, 747 52nd Street, Oakland, CA 94609-1809, USA.
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109
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Imren S, Fabry ME, Westerman KA, Pawliuk R, Tang P, Rosten PM, Nagel RL, Leboulch P, Eaves CJ, Humphries RK. High-level beta-globin expression and preferred intragenic integration after lentiviral transduction of human cord blood stem cells. J Clin Invest 2004; 114:953-62. [PMID: 15467834 PMCID: PMC518665 DOI: 10.1172/jci21838] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2004] [Accepted: 07/20/2004] [Indexed: 11/17/2022] Open
Abstract
Transplantation of genetically corrected autologous hematopoietic stem cells is an attractive approach for the cure of sickle-cell disease and beta-thalassemia. Here, we infected human cord blood cells with a self-inactivating lentiviral vector encoding an anti-sickling betaA-T87Q-globin transgene and analyzed the transduced progeny produced over a 6-month period after transplantation of the infected cells directly into sublethally irradiated NOD/LtSz-scid/scid mice. Approximately half of the human erythroid and myeloid progenitors regenerated in the mice containing the transgene, and erythroid cells derived in vitro from these in vivo-regenerated cells produced high levels of betaA-T87Q-globin protein. Linker-mediated PCR analysis identified multiple transgene-positive clones in all mice analyzed with 2.1 +/- 0.1 integrated proviral copies per cell. Genomic sequencing of vector-containing fragments showed that 86% of the proviral inserts had occurred within genes, including several genes implicated in human leukemia. These findings indicate effective transduction of very primitive human cord blood cells with a candidate therapeutic lentiviral vector resulting in the long-term and robust, erythroid-specific production of therapeutically relevant levels of beta-globin protein. However, the frequency of proviral integration within genes that regulate hematopoiesis points to a need for additional safety modifications.
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Affiliation(s)
- Suzan Imren
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
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110
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Imren S, Fabry ME, Westerman KA, Pawliuk R, Tang P, Rosten PM, Nagel RL, Leboulch P, Eaves CJ, Humphries RK. High-level β-globin expression and preferred intragenic integration after lentiviral transduction of human cord blood stem cells. J Clin Invest 2004. [DOI: 10.1172/jci200421838] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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111
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Puthenveetil G, Scholes J, Carbonell D, Qureshi N, Xia P, Zeng L, Li S, Yu Y, Hiti AL, Yee JK, Malik P. Successful correction of the human beta-thalassemia major phenotype using a lentiviral vector. Blood 2004; 104:3445-53. [PMID: 15292064 DOI: 10.1182/blood-2004-04-1427] [Citation(s) in RCA: 143] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
beta-thalassemias are the most common single gene disorders and are potentially amenable to gene therapy. However, retroviral vectors carrying the human beta-globin cassette have been notoriously unstable. Recently, considerable progress has been made using lentiviral vectors, which stably transmit the beta-globin expression cassette. Thus far, mouse studies have shown correction of the beta-thalassemia intermedia phenotype and a partial, variable correction of beta-thalassemia major phenotype. We tested a lentiviral vector carrying the human beta-globin expression cassette flanked by a chromatin insulator in transfusion-dependent human thalassemia major, where it would be ultimately relevant. We demonstrated that the vector expressed normal amounts of human beta-globin in erythroid cells produced in in vitro cultures for unilineage erythroid differentiation. There was restoration of effective erythropoiesis and reversal of the abnormally elevated apoptosis that characterizes beta-thalassemia. The gene-corrected human beta-thalassemia progenitor cells were transplanted into immune-deficient mice, where they underwent normal erythroid differentiation, expressed normal levels of human beta-globin, and displayed normal effective erythropoiesis 3 to 4 months after xenotransplantation. Variability of beta-globin expression in erythroid colonies derived in vitro or from xenograft bone marrow was similar to that seen in normal controls. Our results show genetic modification of primitive progenitor cells with correction of the human thalassemia major phenotype.
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Affiliation(s)
- Geetha Puthenveetil
- Saban Research Institute, Division of Hematology-Oncology, Childrens Hospital Los Angeles, Mail Stop 54, 4650 Sunset Blvd, Los Angeles, CA 90027, USA
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112
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Bakkenist CJ, Drissi R, Wu J, Kastan MB, Dome JS. Disappearance of the telomere dysfunction-induced stress response in fully senescent cells. Cancer Res 2004; 64:3748-52. [PMID: 15172978 DOI: 10.1158/0008-5472.can-04-0453] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Replicative senescence is a natural barrier to cellular proliferation that is triggered by telomere erosion and dysfunction. Here, we demonstrate that ATM activation and H2AX-gamma nuclear focus formation are sensitive markers of telomere dysfunction in primary human fibroblasts. Whereas the activated form of ATM and H2AX-gamma foci were rarely observed in early-passage cells, they were readily detected in late-passage cells. The ectopic expression of telomerase in late-passage cells abrogated ATM activation and H2AX-gamma focus formation, suggesting that these stress responses were the consequence of telomere dysfunction. ATM activation was induced in quiescent fibroblasts by inhibition of TRF2 binding to telomeres, indicating that telomere uncapping is sufficient to initiate the telomere signaling response; breakage of chromosomes with telomeric associations is not required for this activation. Although ATM activation and H2AX-gamma foci were readily observed in late-passage cells, they disappeared once cells became fully senescent, indicating that constitutive signaling from dysfunctional telomeres is not required for the maintenance of senescence.
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Affiliation(s)
- Christopher J Bakkenist
- Department of Hematology/Oncology, St Jude Children's Research Hospital, Memphis, Tennessee 38105, USA
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113
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Hanawa H, Hargrove PW, Kepes S, Srivastava DK, Nienhuis AW, Persons DA. Extended beta-globin locus control region elements promote consistent therapeutic expression of a gamma-globin lentiviral vector in murine beta-thalassemia. Blood 2004; 104:2281-90. [PMID: 15198957 DOI: 10.1182/blood-2004-03-0863] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Since increased fetal hemoglobin diminishes the severity of beta-thalassemia and sickle cell anemia, a strategy using autologous, stem cell-targeted gene transfer of a gamma-globin gene may be therapeutically useful. We previously found that a gamma-globin lentiviral vector utilizing the beta-globin promoter and elements from the beta-globin locus control region (LCR) totaling 1.7 kb could correct murine beta-thalassemia. However, therapeutic consistency was compromised by chromosomal position effects on vector expression. In contrast, we show here that the majority of animals that received transplants of beta-thalassemic stem cells transduced with a new vector containing 3.2 kb of LCR sequences expressed high levels of fetal hemoglobin (17%-33%), with an average vector copy number of 1.3. This led to a mean 26 g/L (2.6 g/dL) increase in hemoglobin concentration and enhanced amelioration of other hematologic parameters. Analysis of clonal erythroid cells of secondary spleen colonies from mice that underwent transplantation demonstrated an increased resistance of the larger LCR vector to stable and variegating position effects. This trend was also observed for vector insertion sites located inside genes, where vector expression was often compromised, in contrast to intergenic sites, where higher levels of expression were observed. These data emphasize the importance of overcoming detrimental position effects for consistent therapeutic globin vector expression.
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Affiliation(s)
- Hideki Hanawa
- 332 North Lauderdale Dr, St Jude Children's Research Hospital, Memphis, TN 38105, USA
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114
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Stathopulos PB. Taking the good out of the bad: lentiviral-based gene therapy of the hemoglobinopathies. Biotechnol Adv 2004; 21:513-26. [PMID: 14499152 DOI: 10.1016/s0734-9750(03)00102-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Sickle cell disease and beta-thalassemia are excellent candidates for gene therapy since transfer of a single gene into hematopoietic stem cells should theoretically elicit a therapeutic response. Initial attempts at gene therapy of these hemoglobinopathies have proved unsuccessful due to limitations of available gene transfer vectors. With the extensive research on human immunodeficiency virus-1 due to the acquired immune deficiency syndrome pandemic, researchers have realized that this lentivirus, engineered to be devoid of any pathogenic elements, can be an effective gene transfer vector. This review discusses the gene therapy strategy for the hemoglobinopathies and outlines why lentiviral-derived vectors are particularly suited for this type of application, keeping past failures at gene therapy of these hemoglobinopathies in mind. Development, improvement, and methods for preparation of lentiviral-derived vectors are examined. Recently published results of successful gene therapy treatment of beta-thalassemic and sickle cell diseased mice using lentiviral-derived vectors are described. Finally, criticisms and future directions of lentiviral-based biotechnology are considered.
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Affiliation(s)
- Peter B Stathopulos
- Department of Biology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, Canada N2L 3G1.
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115
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Richard RE, Weinreich M, Chang KH, Ieremia J, Stevenson MM, Blau CA. Modulating erythrocyte chimerism in a mouse model of pyruvate kinase deficiency. Blood 2004; 103:4432-9. [PMID: 14988153 DOI: 10.1182/blood-2003-10-3705] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
In vivo selection may provide a means to increase the relative number of cells of donor origin in recipients with hemopoietic chimerism. We have tested whether in vivo selection using chemical inducers of dimerization (CIDs) can direct the expansion of transduced normal donor erythrocytes in recipients with chimerism using a mouse model of pyruvate kinase deficiency. Marrow cells from normal CBA/N mice were transduced with a vector (F36Vmpl(GFP)) that promotes cell growth in the presence of CIDs. Transduced cells were then transplanted into minimally conditioned, pyruvate kinase-deficient recipients (CBA-Pk-1(slc)/Pk-1(slc)) to establish stable chimerism. CID administration resulted in expansion of normal donor erythrocytes and improvement of the anemia. The preferential expansion of normal erythrocytes also resulted in a decrease in erythropoietin levels, reducing the drive for production of pyruvate kinase-deficient red blood cells. CID-mediated expansion of genetically modified erythrocytes could prove a useful adjunct to transplantation methods that achieve erythroid chimerism.
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Affiliation(s)
- Robert E Richard
- Department of Medicine, Mailstop 357710, Health Sciences Building, University of Washington, Seattle, WA 98195, USA.
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116
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Hanawa H, Hematti P, Keyvanfar K, Metzger ME, Krouse A, Donahue RE, Kepes S, Gray J, Dunbar CE, Persons DA, Nienhuis AW. Efficient gene transfer into rhesus repopulating hematopoietic stem cells using a simian immunodeficiency virus-based lentiviral vector system. Blood 2004; 103:4062-9. [PMID: 14976042 DOI: 10.1182/blood-2004-01-0045] [Citation(s) in RCA: 139] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
High-titer, HIV-1-based lentiviral vector particles were found to transduce cytokine-mobilized rhesus macaque CD34(+) cells and clonogenic progenitors very poorly (< 1%), reflecting the postentry restriction in rhesus cells to HIV infection. To overcome this barrier, we developed a simian immunodeficiency virus (SIV)-based vector system. A single exposure to a low concentration of amphotropic pseudotyped SIV vector particles encoding the green fluorescent protein (GFP) resulted in gene transfer into 68% +/- 1% of rhesus bulk CD34(+) cells and 75% +/- 1% of clonogenic progenitors. Polymerase chain reaction (PCR) analysis of DNA from individual hematopoietic colonies confirmed these relative transduction efficiencies. To evaluate SIV vector-mediated stem cell gene transfer in vivo, 3 rhesus macaques underwent transplantation with transduced, autologous cytokine-mobilized peripheral blood CD34(+) cells following myeloablative conditioning. Hematopoietic reconstitution was rapid, and an average of 18% +/- 8% and 15% +/- 7% GFP-positive granulocytes and monocytes, respectively, were observed 4 to 6 months after transplantation, consistent with the average vector copy number of 0.19 +/- 0.05 in peripheral blood leukocytes as determined by real-time PCR. Vector insertion site analysis demonstrated polyclonal reconstitution with vector-containing cells. SIV vectors appear promising for evaluating gene therapy approaches in nonhuman primate models.
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Affiliation(s)
- Hideki Hanawa
- Experimental Hematology Division, Department of Hematology/Oncology, St Jude Children's Research Hospital, 332 N Lauderdale, Memphis, TN 38105, USA
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117
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Levasseur DN, Ryan TM, Pawlik KM, Townes TM. Correction of a mouse model of sickle cell disease: lentiviral/antisickling beta-globin gene transduction of unmobilized, purified hematopoietic stem cells. Blood 2003; 102:4312-9. [PMID: 12933581 DOI: 10.1182/blood-2003-04-1251] [Citation(s) in RCA: 148] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Although sickle cell anemia was the first hereditary disease to be understood at the molecular level, there is still no adequate long-term treatment. Allogeneic bone marrow transplantation is the only available cure, but this procedure is limited to a minority of patients with an available, histocompatible donor. Autologous transplantation of bone marrow stem cells that are transduced with a stably expressed, antisickling globin gene would benefit a majority of patients with sickle cell disease. Therefore, the development of a gene therapy protocol that corrects the disease in an animal model and is directly translatable to human patients is critical. A method is described in which unmobilized, highly purified bone marrow stem cells are transduced with a minimum amount of self-inactivating (SIN) lentiviral vector containing a potent antisickling beta-globin gene. These cells, which were transduced in the absence of cytokine stimulation, fully reconstitute irradiated recipients and correct the hemolytic anemia and organ pathology that characterize the disease in humans. The mean increase of hemoglobin concentration was 46 g/L (4.6 g/dL) and the average lentiviral copy number was 2.2; therefore, a 21-g/L /vector copy increase (2.1-g/dL) was achieved. This transduction protocol may be directly translatable to patients with sickle cell disease who cannot tolerate current bone marrow mobilization procedures and may not safely be exposed to large viral loads.
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Affiliation(s)
- Dana N Levasseur
- Department of Biochemistry and Molecular Genetics, Schools of Medicine and Dentistry, University of Alabama at Birmingham, USA
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118
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Persons DA, Allay ER, Sawai N, Hargrove PW, Brent TP, Hanawa H, Nienhuis AW, Sorrentino BP. Successful treatment of murine beta-thalassemia using in vivo selection of genetically modified, drug-resistant hematopoietic stem cells. Blood 2003; 102:506-13. [PMID: 12663444 DOI: 10.1182/blood-2003-03-0677] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Successful gene therapy of beta-thalassemia will require replacement of the abnormal erythroid compartment with erythropoiesis derived from genetically corrected, autologous hematopoietic stem cells (HSCs). However, currently attainable gene transfer efficiencies into human HSCs are unlikely to yield sufficient numbers of corrected cells for a clinical benefit. Here, using a murine model of beta-thalassemia, we demonstrate for the first time that selective enrichment in vivo of transplanted, drug-resistant HSCs can be used therapeutically and may therefore be a useful approach to overcome limiting gene transfer. We used an oncoretroviral vector to transfer a methylguanine methyltransferase (MGMT) drug-resistance gene into normal bone marrow cells. These cells were transplanted into beta-thalassemic mice given nonmyeloablative pretransplantation conditioning with temozolomide (TMZ) and O6-benzylguanine (BG). A majority of mice receiving 2 additional courses of TMZ/BG demonstrated in vivo selection of the drug-resistant cells and amelioration of anemia, compared with untreated control animals. These results were extended using a novel gamma-globin/MGMT dual gene lentiviral vector. Following drug treatment, normal mice that received transduced cells had an average 67-fold increase in gamma-globin expressing red cells. These studies demonstrate that MGMT-based in vivo selection may be useful to increase genetically corrected cells to therapeutic levels in patients with beta-thalassemia.
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Affiliation(s)
- Derek A Persons
- Division of Experimental Hematology, Department of Hematology, St Jude Children's Research Hospital, Memphis, TN, USA.
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119
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Ramezani A, Hawley TS, Hawley RG. Performance- and safety-enhanced lentiviral vectors containing the human interferon-beta scaffold attachment region and the chicken beta-globin insulator. Blood 2003; 101:4717-24. [PMID: 12586614 DOI: 10.1182/blood-2002-09-2991] [Citation(s) in RCA: 124] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Retroviral vectors are the most efficient means of stable gene delivery to hematopoietic stem cells (HSCs). However, transgene expression from retroviral vectors is frequently subject to the negative influence of chromosomal sequences flanking the site of integration. Toward the development of autonomous transgene expression cassettes, we inserted the human interferon-beta scaffold attachment region (IFN-SAR) and the chicken beta-globin 5' DNase I hypersensitive site 4 (5'HS4) insulator both separately and together into a series of self-inactivating (SIN) lentiviral vector backbones. Transduced cells of the human CD34+ hematopoietic progenitor line KG1a-pooled populations as well as individual clones harboring single integrants--were analyzed for reporter expression during culture periods of up to 4 months. Vectors carrying both the 5'HS4 insulator and the IFN-SAR consistently outperformed control vectors without inserts as well as vectors carrying either element alone. The performance of a set of vectors containing the murine stem cell virus long terminal repeat as an internal promoter was subsequently assessed during in vitro monocytic differentiation of transduced primary human CD34+ cord blood cells. Similar to what was observed in the KG1a hematopoietic progenitor cell model, optimal reporter expression in primary monocytes was obtained with the vector bearing both regulatory elements. These findings indicate that the 5'HS4/IFN-SAR combination is particularly effective at maintaining open chromatin domains permissive for high-level transgene expression at early and late stages of hematopoietic development, and thus could be of utility in HSC-directed retroviral vector-mediated gene transfer applications.
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Affiliation(s)
- Ali Ramezani
- Hematopoiesis Department, Flow Cytometry Facility, American Red Cross, Rockville, MD 20855, USA
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120
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Brümmendorf TH, Orlic D, Fibbe WE, Sharkis S, Kanz L. Meeting summary: International Symposium and Workshop on Hematopoietic Stem Cells IV, University of Tübingen, Germany, September 19-21, 2002. Exp Hematol 2003; 31:475-82. [PMID: 12829022 DOI: 10.1016/s0301-472x(03)00073-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Tim H Brümmendorf
- Department of Hematology, Oncology and Immunology, University Medical Center II, Otfried-Müller-Strasse 10, 72076 Tübingen, Germany
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121
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Nienhuis AW, Hanawa H, Sawai N, Sorrentino BP, Persons DA. Development of gene therapy for hemoglobin disorders. Ann N Y Acad Sci 2003; 996:101-11. [PMID: 12799288 DOI: 10.1111/j.1749-6632.2003.tb03238.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The hemoglobin disorders, severe beta-thalassemia and sickle cell anemia, are prevalent monogenetic disorders which cause severe morbidity and mortality worldwide. Gene therapy approaches to these disorders envision stem cell targeted gene transfer, autologous transplantation of gene-corrected stem cells, and functional, phenotypically corrective globin gene expression in developing erythroid cells. Lentiviral vector systems potentially appear to afford adequately efficient gene transfer into stem cells and are capable, with appropriate genetic engineering, of transferring a globin gene with the regulatory elements required to achieve high-level, erythroid-specific expression. Herein are results obtained in use of lentiviral vectors to insert a gamma-globin gene into murine stem cells with phenotypic correction of the thalassemia phenotype. Further, we have developed a drug-selection system for genetically modified stem cells based on a mutant form of methylguanine, methyltransferase, which allows selective amplification of genetically modified stem cells with phenotypic correction even in the absence of myeloablation prior to stem cell transplantation. These advances provide essential preclinical data which build toward the development of effective gene therapy for the severe hemoglobin disorders.
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Affiliation(s)
- Arthur W Nienhuis
- Division of Experimental Hematology, Department of Hematology/Oncology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA.
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