Almarza Elena, Río Paula, Meza Nestor W, Aldea Montserrat, Agirre Xabier, Guenechea Guillermo, Segovia José C, Bueren Juan A
Hematopoiesis and Gene Therapy Division, CIEMAT/CIBER-ER and Marcelino Botín Foundation, Madrid, Spain.
Mol Ther. 2007 Aug;15(8):1487-94. doi: 10.1038/sj.mt.6300213. Epub 2007 May 29.
Recent published data have shown the efficacy of gene therapy treatments of certain monogenic diseases. Risks of insertional oncogenesis, however, indicate the necessity of developing new vectors with weaker or cell-restricted promoters to minimize the trans-activation activity of integrated proviruses. We have inserted the proximal promoter of the vav proto-oncogene into self-inactivating lentiviral vectors (vav-LVs) and investigated the expression pattern and therapeutic efficacy of these vectors. Compared with other LVs frequently used in gene therapy, vav-LVs mediated a weak, though homogeneous and stable, expression in in vitro-cultured cells. Transplantation experiments using transduced mouse bone marrow and human CD34(+) cells confirmed the stable activity of the promoter in vivo. To investigate whether the weak activity of this promoter was compatible with a therapeutic effect, a LV expressing the Fanconi anemia A (FANCA) gene was constructed (vav-FANCA LV). Although this vector induced a low expression of FANCA, compared to the expression induced by a LV harboring the spleen focus-forming virus (SFFV) promoter, the two vectors corrected the phenotype of cells from a patient with FA-A with the same efficacy. We propose that self-inactivating vectors harboring weak promoters, such as the vav promoter, will improve the safety of gene therapy and will be of particular interest for the treatment of diseases where a high expression of the transgene is not required.
最近发表的数据显示了基因治疗某些单基因疾病的疗效。然而，插入性致癌的风险表明，有必要开发具有较弱或细胞限制性启动子的新型载体，以尽量减少整合前病毒的反式激活活性。我们已将vav原癌基因的近端启动子插入到自失活慢病毒载体（vav-LV）中，并研究了这些载体的表达模式和治疗效果。与基因治疗中常用的其他慢病毒载体相比，vav-LV在体外培养细胞中介导了一种微弱但均匀且稳定的表达。使用转导的小鼠骨髓和人CD34(+)细胞进行的移植实验证实了该启动子在体内的稳定活性。为了研究该启动子的弱活性是否与治疗效果兼容，构建了一种表达范可尼贫血A（FANCA）基因的慢病毒载体（vav-FANCA LV）。尽管与携带脾集落形成病毒（SFFV）启动子的慢病毒载体诱导的表达相比，该载体诱导的FANCA表达较低，但这两种载体对FA-A患者细胞表型的校正效果相同。我们提出，携带弱启动子（如vav启动子）的自失活载体将提高基因治疗的安全性，对于不需要高表达转基因的疾病治疗将特别有意义。
