title: Stem cell marking with promotor-deprived self-inactivating retroviral vectors does not lead to induced clonal imbalance.
abstract: Stable genetic modification of stem cells holds great promise for gene therapy and marking, but commonly used gamma-retroviral vectors were found to influence growth/survival characteristics of hematopoietic stem cells (HSCs) by insertional mutagenesis. In this article, we show that promoter-deprived gamma-retroviral self-inactivating (pd-SIN) vectors allow stable genetic marking of serially reconstituting murine HSC. In contrast to findings with gamma-retroviral long terminal repeat (LTR) vectors, serial transplantation of pd-SIN-marked HSC in a sensitive mouse model was apparently not associated with induced clonal imbalance of gene-marked HSC. Furthermore, insertions of pd-SIN into protooncogenes, growth-promoting and signaling genes occurred significantly less frequent than in control experiments with LTR vectors. Also, transcriptional dysregulation of neighboring genes potentially caused by the pd-SIN insertion was rarely seen and comparatively weak. The integration pattern of promotor-deprived SIN vectors in reconstituting HSC seems to depend on the transcriptional activity of the respective gene loci reflecting the picture described for LTR vectors. In conclusion, our data strongly support the use of SIN vectors for gene-marking studies and suggest an increased therapeutic index for vectors lacking enhancers active in HSC.
authors.affiliation: Experimental Pediatric Oncology and Hematology, Pediatric Clinic III, University Hospital of the Johann Wolfgang Goethe-University, Frankfurt am Main, Germany.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Cornils
authors.forename: Claudia
authors.initials: C
authors.lastname: Lange
authors.forename: Axel
authors.initials: A
authors.lastname: Schambach
authors.forename: Martijn H
authors.initials: MH
authors.lastname: Brugman
authors.forename: Regine
authors.initials: R
authors.lastname: Nowak
authors.forename: Michael
authors.initials: M
authors.lastname: Lioznov
authors.forename: Christopher
authors.initials: C
authors.lastname: Baum
authors.forename: Boris
authors.initials: B
authors.lastname: Fehse
mesh_terms: D000818:Animals; D005822:Genetic Vectors / Q000235:genetics*; D006412:Hematopoietic Stem Cells / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D016254:Mutagenesis, Insertional; D016133:Polymerase Chain Reaction; D012190:Retroviridae / Q000235:genetics*; D014158:Transcription, Genetic / Q000235:genetics