Safer Vectors and Strategies For Gene Therapy

描述(由申请人提供)：逆转录病毒载体是将基因产品稳定地输送到有治疗意义的细胞中的极佳工具。然而，这些载体在临床环境中的使用最近被证明是有问题的。在一项纠正严重联合免疫缺陷(SCID)的基因治疗试验中，11名患者中有2名患者由于整合的逆转录病毒载体直接导致T细胞白血病。为了防止在未来的基因治疗试验中出现不良结果，本研究的一个主要目标是开发和测试新的载体和策略，目的是在不损失有效性的情况下提高安全性。将开发新的载体，这种载体不太可能导致插入突变，同时仍能保留治疗益处。这将需要设计具有增强子阻断活性的DMA元件，以抑制基因组DMA中相邻基因的反式激活。加入可调控的自杀基因将提供额外的安全功能，这种基因可以在出现不利结果的情况下被激活。最后，上面讨论的载体和策略，以及有限数量的转基因细胞的使用，将测试它们修复免疫缺陷小鼠模型中的遗传缺陷的能力。该项目的目的是在生产最安全、最有效的逆转录病毒载体用于人类基因治疗试验的过程中，以安全的方式提高疗效。

DESCRIPTION (provided by applicant): Retroviral vectors are excellent tools for the stable delivery of gene products into cells of therapeutic interest. However, use of these vectors in a clinical setting has recently been shown to be problematic. In a gene therapy trial for the correction of Severe Combined Immune Deficiency (SCID), two patients, out of eleven, developed T-cell leukemia as a direct result of an integrated retroviral vector. In an effort to prevent undesirable outcomes in future gene therapy trials, a primary goal of this study is the development and testing of novel vectors and strategies aimed at increased safety without the loss of effectiveness. New vectors will be developed that are less likely to lead to insertional mutagenesis while still retaining the therapeutic benefits. This will require the engineering of DMA elements with enhancer-blocking activity to inhibit transactivation of adjacent genes in genomic DMA. Incorporation of a regulatable suicide gene, which could be activated in the case of an adverse outcome, will provide an additional safety feature. Lastly, the vectors and strategies discussed above along with the use of limited numbers of genetically modified cells will be tested for their ability to rescue a genetic defect in a murine model of immunodeficiency. This project is aimed at tempering efficacy with safety in producing the safest, most potent retroviral vectors for use in human gene therapy trials.