title: Lack of genotoxicity due to foamy virus vector integration in human iPSCs.
abstract: Integrating vectors can lead to the dysregulation of nearby chromosomal genes, with important consequences for clinical trials and cellular engineering. This includes the retroviral and lentiviral vectors commonly used for deriving induced pluripotent stem cells (iPSCs). We previously used integrating foamy virus (FV) vectors expressing OCT4, SOX2, MYC and KLF4 to reprogram osteogenesis imperfecta mesenchymal stem cells (MSCs). Here, we have studied the effects of 10 FV vector proviruses on neighboring gene expression in four iPSC lines and their corresponding iPSC-derived MSC (iMSCs). Gene expression profiles in these iPSC lines showed that none of the 38 genes within 300 kb up- or downstream of integrated proviruses had a significant difference in mRNA levels, including five genes with proviruses in their transcription units. In the iMSCs derived from these iPSCs, the same type of analysis showed a single dysregulated transcript out of 46 genes found near proviruses. This frequency of dysregulation was similar to that of genes lacking nearby proviruses, so it may have been due to interclonal variation and/or measurement inaccuracies. While the number of integration sites examined in this paper is limited, our results suggest that integrated FV proviruses do not impact the expression of chromosomal genes in pluripotent human stem cells or their differentiated derivatives. This interpretation is consistent with previous reports that FV vectors have minimal genotoxicity, even when integrating near or within genes.
authors: Departments of Medicine, University of Washington, Seattle, WA 98195, USA.
authors: D R
authors: DR
authors: Deyle
authors: I F
authors: IF
authors: Khan
authors: G
authors: G
authors: Ren
authors: D W
authors: DW
authors: Russell
mesh_terms: D002454:Cell Differentiation / Q000235:genetics; D002460:Cell Line; D018507:Gene Expression Regulation, Developmental; D005822:Genetic Vectors; D006801:Humans; D057026:Induced Pluripotent Stem Cells / Q000166:cytology / Q000378:metabolism*; D000090062:Kruppel-Like Factor 4; D016092:Spumavirus / Q000235:genetics* / Q000472:pathogenicity; D016662:Virus Integration / Q000235:genetics
references: Proc Natl Acad Sci U S A. 2006 Jan 31;103(5):1457-62
references: 16432223
references: Mol Ther. 2009 Nov;17(11):1919-28
references: 19672245
references: J Virol. 2012 Sep;86(17):9088-95
references: 22696657
references: Science. 2009 May 8;324(5928):797-801
references: 19325077
references: Mol Ther. 2008 Mar;16(3):534-40
references: 18209733
references: Int J Cancer. 2006 Mar 15;118(6):1426-9
references: 16187281
references: Proc Natl Acad Sci U S A. 2008 Dec 30;105(52):20641-6
references: 19095799
references: Mol Ther. 2008 Mar;16(3):525-33
references: 18195719
references: Science. 2003 Oct 17;302(5644):415-9
references: 14564000
references: Nature. 2007 Mar 8;446(7132):153-8
references: 17344846
references: Proc Natl Acad Sci U S A. 2006 Jan 31;103(5):1498-503
references: 16428288
references: Nat Med. 2006 Apr;12(4):401-9
references: 16582916
references: Nucleic Acids Res. 1997 Sep 15;25(18):3745-6
references: 9278500
references: Mol Ther. 2009 May;17(5):851-6
references: 19293778
references: Mol Cell Biol. 1989 Nov;9(11):4670-6
references: 2601693
references: Gene Ther. 2011 Jul;18(7):674-81
references: 21368897
references: Mol Ther. 2010 Dec;18(12):2139-45
references: 20978477
references: Mol Ther. 2008 Jan;16(1):187-93
references: 17955022
references: Blood. 2006 Oct 15;108(8):2545-53
references: 16825499
references: Nat Genet. 2009 Oct;41(10):1127-32
references: 19718025
references: Nat Med. 2008 Jan;14(1):93-7
references: 18157138
references: Mol Ther. 2011 Jul;19(7):1273-86
references: 21386821
references: J Virol. 1999 Feb;73(2):1565-72
references: 9882362
references: Stem Cells. 2010 Apr;28(4):687-94
references: 20166152
references: Nature. 2008 Oct 23;455(7216):1069-75
references: 18948947
references: Blood. 2005 Dec 1;106(12):3932-9
references: 16109773
references: Hum Gene Ther. 2011 Feb;22(2):217-24
references: 20738155
references: J Clin Invest. 2008 Sep;118(9):3143-50
references: 18688286
references: Mol Ther. 2012 Jan;20(1):204-13
references: 22031238
references: J Virol. 1997 Oct;71(10):7305-11
references: 9311807
references: J Virol. 1996 Jan;70(1):217-22
references: 8523528
references: Nature. 2010 Sep 16;467(7313):318-22
references: 20844535
references: Nat Biotechnol. 2006 Jun;24(6):687-96
references: 16732270
references: EMBO Mol Med. 2011 Feb;3(2):89-101
references: 21243617
references: Mol Ther. 2008 Apr;16(4):718-25
references: 18334985
references: Mol Ther. 2009 Apr;17(4):716-24
references: 19240697
references: Mol Ther. 2009 Nov;17(11):1929-37
references: 19707188
references: Mol Ther. 2002 Sep;6(3):321-8
references: 12231167
references: J Clin Invest. 2012 May;122(5):1653-66
references: 22523069