title: Improved retroviral vectors for hematopoietic stem cell protection and in vivo selection.
abstract: Therapeutic gene transfer into hematopoietic cells is critically dependent on the evolution of methods that allow ex vivo expansion, high-frequency transduction, and selection of gene-modified long-term repopulating cells. Progress in this area needs elaboration of defined culture and transduction conditions for long-term repopulating cells and improvement of gene transfer systems. We have optimized retroviral vector constructions based on murine leukemia viruses (MuLV) to overcome the transcriptional repression encountered with the use of conventional Moloney MuLV (MoMuLV) vectors in early hematopoietic progenitor cells (HPC). Novel retroviral vectors, termed FMEV (for Friend-MCF/MESV hybrid vectors), were cloned that mediate greatly improved gene expression in the myeloerythroid compartment. Transfer of the selectable marker multidrug resistance 1 (mdr1), FMEV, in contrast to conventional MoMuLV-related vectors currently in use for clinical protocols, mediated background-free selectability of transduced human HPC in the presence of myeloablative doses of the cytostatic agent paclitaxel in vitro. Furthermore, FMEV also greatly improved chemo-protection of hematopoietic progenitor cells in a murine model system in vivo. Finally, when a second gene was transferred along with mdr1 in an FMEV-backbone, close to 100% coexpression was observed in multidrug-resistant colonies. These observations have significant consequences for a number of ongoing and planned gene therapy trials, for example, stem cell protection to reduce the myelotoxic side effects of anticancer chemotherapy, correction of inherited disorders involving hematopoietic cells, and antagonism of HIV infection.
authors.affiliation: Abteilung Zell- und Virusgenetik, Heinrich-Pette-Institut für Experimentelle Virologie und Immunologie an der Universität Hamburg, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Baum
authors.forename: H G
authors.initials: HG
authors.lastname: Eckert
authors.forename: M
authors.initials: M
authors.lastname: Stockschläder
authors.forename: U
authors.initials: U
authors.lastname: Just
authors.forename: S
authors.initials: S
authors.lastname: Hegewisch-Becker
authors.forename: M
authors.initials: M
authors.lastname: Hildinger
authors.forename: A
authors.initials: A
authors.lastname: Uhde
authors.forename: J
authors.initials: J
authors.lastname: John
authors.forename: W
authors.initials: W
authors.lastname: Ostertag
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics*; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D001853:Bone Marrow / Q000187:drug effects; D002478:Cells, Cultured; D018432:Drug Resistance, Multiple / Q000235:genetics; D019008:Drug Resistance, Neoplasm / Q000235:genetics; D005622:Friend murine leukemia virus / Q000235:genetics; D017988:Gammaretrovirus / Q000235:genetics*; D015967:Gene Expression Regulation, Viral; D018014:Gene Transfer Techniques; D019450:Genes, MDR; D005822:Genetic Vectors; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells / Q000187:drug effects; D006801:Humans; D008780:Methyltransferases / Q000235:genetics*; D051379:Mice; D008810:Mice, Inbred C57BL; D008908:Mink Cell Focus-Inducing Viruses / Q000235:genetics; D008979:Moloney murine leukemia virus / Q000235:genetics; D019853:O(6)-Methylguanine-DNA Methyltransferase; D017239:Paclitaxel / Q000494:pharmacology; D012449:Safety; D012641:Selection, Genetic; D014158:Transcription, Genetic; D019172:Transplantation Conditioning
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000970:Antineoplastic Agents; D008780:Methyltransferases; D019853:O(6)-Methylguanine-DNA Methyltransferase; D017239:Paclitaxel