Wake Forest Institute for Regenerative Medicine, Wake Forest University Health Sciences, Winston-Salem, NC 27157, USA.
Biomaterials. 2012 Oct;33(29):7261-71. doi: 10.1016/j.biomaterials.2012.06.038. Epub 2012 Jul 12.
Pluripotent stem cells provide an unlimited cell source for cell therapy. However, residual pluripotent stem cells after differentiation can form tumors. Modifying stem cells with suicide constructs through integrating plasmid DNA and viral vectors has been attempted to specifically eliminate residual pluripotent stem cells after differentiation. However, integration of foreign DNA has the potential of insertional mutagenesis, position effects and silencing. Scaffold/matrix attachment region (S/MAR)-based plasmid DNA can be maintained extra-chromosomally, offering a safer alternative to integrating vectors for this purpose. Here, we report the design of an S/MAR-based suicide construct capable of episomal maintenance and specifically killing pluripotent stem cells but not differentiated cells in the presence of ganciclovir. Treating cells differentiated from episomal suicide construct-modified stem cells with ganciclovir reduces the tumor formation risk after cell transplantation. Tumors formed by such modified pluripotent stem cells could be inhibited by ganciclovir administration. This episomal suicide construct enables negative selection of residual pluripotent stem cells in vitro and control of tumors formed from residual pluripotent stem cells in vivo.
多能干细胞为细胞治疗提供了无限的细胞来源。然而，分化后的残留多能干细胞可能会形成肿瘤。通过整合质粒 DNA 和病毒载体，用自杀构建物修饰干细胞，已尝试专门消除分化后残留的多能干细胞。然而，外源 DNA 的整合具有插入突变、位置效应和沉默的潜在风险。基于支架/基质附着区 (S/MAR) 的质粒 DNA 可以在染色体外维持，为该目的提供了比整合载体更安全的替代方案。在这里，我们报告了一种基于 S/MAR 的自杀构建物的设计，该构建物能够在存在更昔洛韦的情况下进行附加体维持，并特异性杀死多能干细胞，但不杀死分化细胞。用更昔洛韦处理来自附加体自杀构建物修饰的干细胞分化的细胞可降低细胞移植后形成肿瘤的风险。用更昔洛韦治疗可抑制此类修饰的多能干细胞形成的肿瘤。这种附加体自杀构建物可在体外进行残留多能干细胞的负选择，并控制体内由残留多能干细胞形成的肿瘤。
