title: Characteristics of lentiviral vectors harboring the proximal promoter of the vav proto-oncogene: a weak and efficient promoter for gene therapy.
abstract: 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.
authors.affiliation: Hematopoiesis and Gene Therapy Division, CIEMAT/CIBER-ER and Marcelino Botín Foundation, Madrid, Spain.
authors.forename: Elena
authors.initials: E
authors.lastname: Almarza
authors.forename: Paula
authors.initials: P
authors.lastname: Río
authors.forename: Nestor W
authors.initials: NW
authors.lastname: Meza
authors.forename: Montserrat
authors.initials: M
authors.lastname: Aldea
authors.forename: Xabier
authors.initials: X
authors.lastname: Agirre
authors.forename: Guillermo
authors.initials: G
authors.lastname: Guenechea
authors.forename: José C
authors.initials: JC
authors.lastname: Segovia
authors.forename: Juan A
authors.initials: JA
authors.lastname: Bueren
mesh_terms: D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured; D019175:DNA Methylation; D052217:Fanconi Anemia Complementation Group A Protein / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D005786:Gene Expression Regulation; D018014:Gene Transfer Techniques; D015316:Genetic Therapy; D005822:Genetic Vectors / Q000235:genetics*; D006801:Humans; D016086:Lentivirus / Q000235:genetics*; D051379:Mice; D010641:Phenotype; D011401:Promoter Regions, Genetic / Q000235:genetics*; D000090063:Proto-Oncogene Mas; D051567:Proto-Oncogene Proteins c-vav / Q000235:genetics / Q000378:metabolism*
chemical_list: D052217:Fanconi Anemia Complementation Group A Protein; C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D051567:Proto-Oncogene Proteins c-vav