Division of Infectious Diseases-Center for Human Virology, Department of Medicine, Thomas Jefferson University, Philadelphia, PA 19107, USA.
Gene Ther. 2013 Jun;20(6):581-8. doi: 10.1038/gt.2012.88. Epub 2012 Nov 22.
Replication-deficient retroviruses have been successfully utilized as vectors, offering an efficient, stable method of therapeutic gene delivery. Many examples exist proving this mode of integrative gene transfer is both effective and safe in cultured systems and clinical trials. Along with their success, severe side effects have occurred with early retroviral vectors causing a shift in the approach to vector design before further clinical testing. Several alternative delivery methods are available but lentiviral vectors (LV) are among the most favorable as they are already well understood. LV offer safer integration site selection profiles and a lower degree of genotoxicity, compared with γ-retroviral vectors. Following their introduction, development of the self-inactivating vector configuration was a huge step to this mode of therapy but did not confer full protection against insertional mutagenesis. As a result integration, modeling must be improved to eventually avoid this possibility. The cellular factor LEDGF/p75 seems to play an essential role in the process of LV site selection and its interactions with chromatin are being quickly resolved. LEDGF/p75 is at the center of one example directed integration effort where recombinant products bias the integration event, a step toward fully directed integration into pre-determined benign loci. A more accurate picture of the details of LEDGF/p75 in the natural integration process is emerging, including new binding specificities, chromatin interaction kinetics and additional cellular factors. Together with next-generation sequencing technology and bio-informatics to analyze integration patterns, these advancements will lead to highly focused directed integration, accelerating wide-spread acceptance of LV for gene therapy.
复制缺陷型逆转录病毒已成功用作载体，为治疗基因传递提供了一种高效、稳定的方法。许多例子证明，这种整合基因转移的模式在培养系统和临床试验中既有效又安全。随着它们的成功，早期逆转录病毒载体引起了严重的副作用，导致在进一步的临床测试之前，载体设计方法发生了转变。有几种替代的传递方法，但慢病毒载体（LV）是最受欢迎的，因为它们已经被很好地理解。与γ-逆转录病毒载体相比，LV 提供了更安全的整合位点选择谱和更低程度的遗传毒性。引入 LV 后，自我失活载体构型的开发是该治疗模式的一大步，但不能完全防止插入突变。因此，整合建模必须得到改进，最终避免这种可能性。细胞因子 LEDGF/p75 似乎在 LV 位点选择过程中起着至关重要的作用，其与染色质的相互作用正在迅速解决。LEDGF/p75 是定向整合努力的一个例子的核心，其中重组产物偏向整合事件，朝着完全定向整合到预先确定的良性基因座迈出了一步。对 LEDGF/p75 在自然整合过程中的细节有了更准确的了解，包括新的结合特异性、染色质相互作用动力学和其他细胞因子。与下一代测序技术和生物信息学分析整合模式相结合，这些进展将导致高度集中的定向整合，加速 LV 在基因治疗中的广泛接受。
