title: Treatment of canine leukocyte adhesion deficiency by foamy virus vectors expressing CD18 from a PGK promoter.
abstract: Proto-oncogene activation caused by retroviral vector integration can cause malignancies in gene therapy trials. This has led investigators to search for less genotoxic vectors with minimal enhancer activity and a decreased risk of influencing neighboring chromosomal gene expression after integration. We previously showed that foamy virus (FV) vectors expressing the canine CD18 gene from an internal murine stem cell virus (MSCV) promoter could cure canine leukocyte adhesion deficiency (LAD). Here, we have repeated these studies using a FV vector expressing canine CD18 from a phosphoglycerate kinase (PGK) gene promoter. In vitro analysis showed that this vector did not contain an enhancer that activated neighboring genes, and it expressed CD18 efficiently in canine neutrophils and CD34+ cells. However, dogs that received hematopoietic stem cells transduced with the PGK-CD18 vector continued to suffer from LAD, and sometimes died prematurely of the disease. These studies show that the PGK promoter cannot effectively replace the MSCV promoter in CD18-expressing FV vectors, and they suggest that vectors containing a strong promoter-enhancer may be necessary for the treatment of human LAD.
authors.affiliation: Experimental Transplantation and Immunology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.
authors.forename: T R
authors.initials: TR
authors.lastname: Bauer
authors.forename: E M
authors.initials: EM
authors.lastname: Olson
authors.forename: Y
authors.initials: Y
authors.lastname: Huo
authors.forename: L M
authors.initials: LM
authors.lastname: Tuschong
authors.forename: J M
authors.initials: JM
authors.lastname: Allen
authors.forename: Y
authors.initials: Y
authors.lastname: Li
authors.forename: T H
authors.initials: TH
authors.lastname: Burkholder
authors.forename: D W
authors.initials: DW
authors.lastname: Russell
mesh_terms: D000818:Animals; D018821:CD18 Antigens / Q000235:genetics / Q000378:metabolism*; D004285:Dogs; D015316:Genetic Therapy; D005822:Genetic Vectors; D018380:Hematopoietic Stem Cell Transplantation / Q000379:methods; D018370:Leukocyte-Adhesion Deficiency Syndrome / Q000235:genetics / Q000628:therapy*; D007962:Leukocytes / Q000378:metabolism; D023421:Models, Animal; D009504:Neutrophils / Q000378:metabolism; D010735:Phosphoglycerate Kinase / Q000235:genetics; D011401:Promoter Regions, Genetic; D000090063:Proto-Oncogene Mas; D016092:Spumavirus / Q000235:genetics*
chemical_list: D018821:CD18 Antigens; C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D010735:Phosphoglycerate Kinase