Papapetrou, EP, Lee, G, Malani, N, Setty, M, Riviere, I, Tirunagari, LMS et al.. Genomic safe harbors permit high β-globin transgene expression in thalassemia induced pluripotent stem cells. Nat Biotechnol 29: 73-78

Center for Cell Engineering, Memorial Sloan-Kettering Cancer Center, New York, New York, USA.
Nature Biotechnology (Impact Factor: 41.51). 01/2011; 29(1):73-8. DOI: 10.1038/nbt.1717
Source: PubMed


Realizing the therapeutic potential of human induced pluripotent stem (iPS) cells will require robust, precise and safe strategies for genetic modification, as cell therapies that rely on randomly integrated transgenes pose oncogenic risks. Here we describe a strategy to genetically modify human iPS cells at 'safe harbor' sites in the genome, which fulfill five criteria based on their position relative to contiguous coding genes, microRNAs and ultraconserved regions. We demonstrate that ∼10% of integrations of a lentivirally encoded β-globin transgene in β-thalassemia-patient iPS cell clones meet our safe harbor criteria and permit high-level β-globin expression upon erythroid differentiation without perturbation of neighboring gene expression. This approach, combining bioinformatics and functional analyses, should be broadly applicable to introducing therapeutic or suicide genes into patient-specific iPS cells for use in cell therapy.

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Available from: Kyuichi Kadota
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    • "Generation and hematopoietic differentiation of human iPSCs were performed according to previous protocols (Papapetrou et al., 2011). "
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    • "The human iPSC line thal5.10 was generated with a single, excisable polycistronic vector expressing OCT4, KLF4, MYC, and SOX2 (Papapetrou et al., 2011). The media were changed 24 hr later and replaced every day thereafter with human ESC media supplemented with 6 ng/ml FGF2 (R&D Systems) and 0.5 mM valproic acid (Sigma). "
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    • "The chromosomal locations of the integration sites in clones possessing a single integration in an intergenic region are shown in Figure S2. To evaluate safety, we analyzed the distances to the nearest genes, to cancer genes, and to miRNAs (Fig. S2) to identify “safe harbor” integration sites [31]. For the purposes of this study, we focused on clones 1∶20 #9 (W9) and 1∶10 #13 (W13), the first two single-copy, intergenic mdx iPSC clones we obtained that appeared to have safe integration sites, to pursue further genomic engineering. "
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