A comparison of foamy and lentiviral vector genotoxicity in SCID-repopulating cells shows foamy vectors are less prone to clonal dominance
A comparison of foamy and lentiviral vector genotoxicity in SCID-repopulating cells shows foamy vectors are less prone to clonal dominance
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DOI：
10.1038/mtm.2016.48
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发表时间：
2016-01-01
影响因子：
4.7
通讯作者：
Trobridge, Grant D.
中科院分区：
文献类型：
--
作者：
Everson, Elizabeth M.;Olzsko, Miles E.;Trobridge, Grant D.
利用逆转录病毒载体进行造血干细胞（HSC）基因治疗具有巨大的潜力，但载体介导的遗传毒性限制了其在临床上的应用。慢病毒载体比γ逆转录病毒载体的遗传毒性小，已成为临床试验中的首选载体。泡沫状逆转录病毒载体具有有希望的整合特征，并且与γ逆转录病毒或慢病毒载体相比不易于通读转录。在这里，我们直接比较了泡沫载体和慢病毒载体在免疫缺陷小鼠中的人CD 34重建细胞中的安全性和有效性。为了增加其遗传毒性潜力，使用了具有相同转基因盒的泡沫和慢病毒载体，所述转基因盒具有已知的遗传毒性脾病灶形成病毒启动子。这两种载体导致有效的标记在体内和总共825个泡沫和460个慢病毒载体独特的整合位点被回收在移植后19周的再填充细胞。与慢病毒载体相比，在RefSeq基因和原癌基因转录起始位点附近较少观察到泡沫状载体前病毒。泡沫载体组也是多克隆的，具有比慢病毒载体组（8只小鼠中的8只）更少的显性克隆（6只小鼠中的2只），并且只有慢病毒载体在显性克隆中具有接近已知原癌基因的整合体。我们的数据进一步支持泡沫载体用于HSC基因治疗的相对安全性。
Hematopoietic stem cell (HSC) gene therapy using retroviral vectors has immense potential, but vector-mediated genotoxicity limits use in the clinic. Lentiviral vectors are less genotoxic than gammaretroviral vectors and have become the vector of choice in clinical trials. Foamy retroviral vectors have a promising integration profile and are less prone to read-through transcription than gammaretroviral or lentiviral vectors. Here, we directly compared the safety and efficacy of foamy vectors to lentiviral vectors in human CD34 - repopulating cells in immunodeficient mice. To increase their genotoxic potential, foamy and lentiviral vectors with identical transgene cassettes with a known genotoxic spleen focus forming virus promoter were used. Both vectors resulted in efficient marking in vivo and a total of 825 foamy and 460 lentiviral vector unique integration sites were recovered in repopulating cells 19 weeks after transplantation. Foamy vector proviruses were observed less often near RefSeq gene and proto-oncogene transcription start sites than lentiviral vectors. The foamy vector group were also more polyclonal with fewer dominant clones (two out of six mice) than the lentiviral vector group (eight out of eight mice), and only lentiviral vectors had integrants near known proto-oncogenes in dominant clones. Our data further support the relative safety of foamy vectors for HSC gene therapy.