title: ABC transporter inhibitors that are substrates enhance lentiviral vector transduction into primitive hematopoietic progenitor cells.
abstract: High gene transfer efficiencies have been difficult to achieve in hematopoietic progenitor cells (HPCs) but are important to therapeutic success of HPC gene therapy. Efficient gene transfer is especially challenging with use of column-purified vector for clinical application, as opposed to centrifuged vector commonly used for research. We investigated novel approaches to increase transduction by using a clinically applicable protocol and quantities of column-purified lentiviral vector. Recognizing the association of adenosine 5'-triphosphate (ATP)-binding cassette (ABC) transporters with HPC biology, we investigated the effect of transporter inhibitors on transduction. We found the ABC transporter inhibitor verapamil improved transduction efficiency 2- to 6-fold into CD34(+) cells isolated from mobilized peripheral blood, bone marrow, and cord blood. Verapamil also improved transduction in human SCID (severe combined immunodeficient) repopulating cell (SRC) transduction 3- to 4-fold, resulting in 80% to 90% transduction levels in mice receiving primary and secondary transplants without alterations in multilineage reconstitution. Additional ABC transporter substrate inhibitors like quinidine, diltiazem, and ritonavir also enhanced transduction 2- to 3-fold, although ABC transporter inhibitors that are not substrates did not. Enhanced transduction was not observed in mature hematopoietic cells, neurospheres, mesenchymal stem cells, or hepatocytes. Enhancement of transduction in HPCs was observed with vesicular stomatitis virus-G (VSV-G)-pseudotyped lentiviral vector but not with vector pseudotyped with RD114. Thus, we present a new approach for efficient delivery to primitive HPCs by VSV-G-pseudotyped lentiviral vectors.
authors.affiliation: VIRxSYS Corp, 200 Perry Pky, Ste 1A, Gaithersburg, MD 20877, USA.
authors.forename: Brian M
authors.initials: BM
authors.lastname: Davis
authors.forename: Laurent
authors.initials: L
authors.lastname: Humeau
authors.forename: Vladimir
authors.initials: V
authors.lastname: Slepushkin
authors.forename: Gwendolyn
authors.initials: G
authors.lastname: Binder
authors.forename: Lauren
authors.initials: L
authors.lastname: Korshalla
authors.forename: Yajin
authors.initials: Y
authors.lastname: Ni
authors.forename: E Oluwakemi
authors.initials: EO
authors.lastname: Ogunjimi
authors.forename: Lan-Fei
authors.initials: LF
authors.lastname: Chang
authors.forename: Xiaobin
authors.initials: X
authors.lastname: Lu
authors.forename: Boro
authors.initials: B
authors.lastname: Dropulic
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000037:antagonists & inhibitors*; D000328:Adult; D000818:Animals; D018952:Antigens, CD34 / Q000032:analysis; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002498:Centrifugation; D004110:Diltiazem / Q000494:pharmacology; D015316:Genetic Therapy / Q000379:methods; D005822:Genetic Vectors; D006367:HeLa Cells; D006412:Hematopoietic Stem Cells / Q000737:chemistry / Q000502:physiology*; D006801:Humans; D016086:Lentivirus / Q000235:genetics*; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D011802:Quinidine / Q000494:pharmacology; D014161:Transduction, Genetic / Q000379:methods*; D014700:Verapamil / Q000494:pharmacology
chemical_list: D018528:ATP-Binding Cassette Transporters; D018952:Antigens, CD34; D002121:Calcium Channel Blockers; D014700:Verapamil; D004110:Diltiazem; D011802:Quinidine