| 1. |
- Baum, C, et al.
(author)
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Chance or necessity? Insertional mutagenesis in gene therapy and its consequences
- 2004
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In: Molecular Therapy. - : Elsevier BV. - 1525-0024 .- 1525-0016. ; 9:1, s. 5-13
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Research review (peer-reviewed)abstract
- Recently, unusual forms of leukemias have developed as complications following retroviral transfer of potentially therapeutic genes into hematopoietic cells. A crucial component in the pathogenesis of these complications was the upregulation of a cellular proto-oncogene by random insertion of the retroviral gene transfer vector. These findings have great implications for the genetic manipulation of somatic stem cells in medicine. This review discusses the extent to which the random oncogene activation may have required disease-specific stimuli of the transgene and the hematopoietic milieu to become leukemogenic. Based on these considerations, we propose approaches to risk prediction and prevention.
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| 2. |
- Cheng, Wing-Shing, et al.
(author)
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A novel TARP-promoter-based adenovirus against hormone-dependent and hormone-refractory prostate cancer
- 2004
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In: Molecular Therapy. - : Elsevier BV. - 1525-0016 .- 1525-0024. ; 10:2, s. 355-364
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Journal article (peer-reviewed)abstract
- TARP (T cell receptor gamma-chain alternate reading frame protein) is a protein that in males is uniquely expressed in prostate epithelial cells and prostate cancer cells. We have previously shown that the transcriptional activity of a chimeric sequence comprising the TARP promoter (TARPp) and the PSA enhancer (PSAe) is strictly controlled by testosterone and highly restricted to cells of prostate origin. Here we report that a chimeric sequence comprising TARPp and the PSMA enhancer (PSMAe) is highly active in testosterone-deprived prostate cancer cells, while a regulatory sequence comprising PSAe, PSMAe, and TARPp (PPT) has high prostate-specific activity both in the presence and in the absence of testosterone. Therefore, the PPT sequence may, in a gene therapy setting, be beneficial to prostate cancer patients that have been treated with androgen withdrawal. A recombinant adenovirus vector with the PPT sequence, shielded from interfering adenoviral sequences by the mouse H19 insulator, yields high and prostate-specific transgene expression both in cell cultures and when prostate cancer, PC-346C, tumors were grown orthotopically in nude mice. Intravenous virus administration reveals both higher activity and higher selectivity for the insulator-shielded PPT sequence than for the immediate-early CMV promoter. Therefore, we believe that an adenovirus with therapeutic gene expression controlled by an insulator-shielded PPT sequence is a promising candidate for gene therapy of prostate cancer.
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| 3. |
- Lindholm, L, et al.
(author)
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Genetic re-targeting of adenovirus using a hyperstable scFv domain and an affibody (R) molecule against Her2/neu
- 2004
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In: Molecular Therapy. - : Elsevier BV. - 1525-0016 .- 1525-0024. ; 9, s. S250-S250
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Journal article (peer-reviewed)abstract
- One important goal in gene therapy is to develop adenovirus (Ad) vectors that are genetically de-targeted as well as re-targeted. Genetic re-targeting of Ad using complex cell-binding ligands has previously not been possible. We have previously demonstrated that ligands for genetic re-targeting of adenoviruses must be able to fold correctly in the cytoplasm of virus producing cells, a milieu that is not conducive to the formation of disulphide bonds. Here, we describe functional Ad5 viruses with fibers and pIX capsid proteins genetically modified to contain two types of complex ligands. One is affibody® molecules, corresponding to small (6 kDa) binding proteins developed by combinatorial protein engineering using a single three-helix bundle staphylococcal protein A domain. The other type is hyperstable antibody scFv domains. The affibody molecule used here (ZH2N) is directed against Her2/neu. Recombinant viruses were constructed with ZH2N in three different positions: (i) at the C-terminus of shaft repeat 7 of de-knobbed fibers; (ii) at the C-terminus of pIX; and (iii) in the HI-loop of the fiber knob. Each of the viruses exhibited a characteristic phenotype regarding fiber content, growth and ability to infect Her2/neu expressing cells. In order to test the potentials of scFv liganded Ad vectors, a hyperstable antibody scFv against b-galactosidase was genetically incorporated into knobless fibers, in tandem with a mutated protein A domain reactive with IgG1 Fc that targeted the virus to Fc-expressing 293 cells. These fibers could be rescued into viable virions that retained the original antigen binding specificity of the scFv, demonstrating the basic potential of hyperstable scFvs for genetic re-targeting of Ad. Quite unexpectedly, the fiber content of Ad with knobless, scFv containing fibers was close to normal in contrast to other Ad with knobless fibers that generally has a much reduced fiber content. The hyperstable scFv was further fused to the C-terminus of the capsid protein pIX. The recombinant molecules could be rescued into viable viruses with wt fibers. The scFv retained its binding-specificity on the recombinant virions. The results demonstrate that, contrary to current beliefs, it is possible to construct Ad that genetically incorporates functional scFvs and other complex ligands into the virus fiber and pIX. The feasibility is demonstrated by the creation of different viruses that are re-targeted to Her2/neu. These viruses are currently in pre-clinical development.
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| 4. |
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| 5. |
- Relander, Thomas, et al.
(author)
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Overexpression of Gibbon Ape Leukemia Virus (GALV) Receptor (GLVR1) on Human CD34(+) Cells Increases Gene Transfer Mediated by GALV Pseudotyped Vectors.
- 2002
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In: Molecular Therapy. - : Elsevier BV. - 1525-0024 .- 1525-0016. ; 6:3, s. 400-406
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Journal article (peer-reviewed)abstract
- Retroviral transduction of CD34(+) cells on Retronectin using gibbon ape leukemia virus (GALV) pseudotyped vectors is inhibited by high concentrations of vector containing medium (VCM). Furthermore, this inhibitory activity is stable for at least 48 hours at 37 degrees C and partially blocks a second hit with a GALV pseudotyped vector. We hypothesized that this inhibition was due to interference at the receptor level between infectious and noninfectious vector particles and that it might be possible to overcome it by increasing receptor expression on target cells. Activation of protein kinase C in CD34(+) cells with the phorbol ester PMA (phorbol 12-myristate 13-acetate) increased the mRNA level of the GALV receptor (GLVR1) and the transduction efficiency (TE), and fully reversed the inhibition of transduction seen with high-titer GALV VCM. A murine stem cell virus (MSCV) vector with the GLVR1 receptor and green fluorescent protein cDNAs (MGLIG) was used to transduce fibroblasts, and clones expressing different levels of GLVR1 were isolated. The TE of these cells using a GALV vector correlated with the level of GLVR1 expression. When CD34(+) cells or K562 cells were first transduced with MGLIG and then with high-titer GALV VCM, no inhibition of transduction was seen. The low level of GLVR1 expression limits gene transfer to K562 and CD34(+) cells using GALV pseudotyped vectors, especially in the presence of high-titer VCMs.
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| 6. |
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| 7. |
- Hamaguchi, Isao, et al.
(author)
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Proliferation deficiency of multipotent hematopoietic progenitors in ribosomal protein S19 (RPS19)-deficient Diamond-Blackfan anemia improves following RPS19 gene transfer
- 2003
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In: Molecular Therapy. - 1525-0024. ; 7:5, s. 613-622
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Journal article (peer-reviewed)abstract
- Diamond-Blackfan anemia (DBA) is a congenital bone marrow failure syndrome characterized by a specific deficiency in erythroid progenitors. Since some patients with DBA develop a reduction in thrombocytes and granulocytes with age, we asked whether multipotent hematopoietic progenitors from DBA patients had normal proliferative capacity in liquid expansion cultures. CD34(+) cells derived from DBA patients showed deficient proliferation in liquid culture containing IL-3, IL-6, and SCF. Single CD34(+) CD38(-) cells from DBA patients exhibited deficient proliferation recruitment in a limiting dilution assay containing IL-3, IL-6, SCF, Tpo, FIL, and G-CSF or containing IL-3, IL-6, and SCF. Our findings suggest that the underlying hematopoietic defect in DBA may not be limited to the erythroid lineage. Since a fraction of DBA patients have a deficiency in ribosomal protein S19 (RPS19), we constructed lentiviral vectors containing the RPS19 gene for overexpression in hematopoietic progenitors from RPS19-deficient DBA patients. Enforced expression of the RPS19 transgene improved the proliferation of CD34(+) cells from DBA patients with RPS19 mutation. Similarly, enforced expression of RPS19 improved erythroid development of RPS19-deficient hematopoietic progenitors as determined by colony assays and erythroid differentiation cultures. These findings suggest that gene therapy for RPS19-deficient DBA is feasible.
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