title: Recurrent retroviral vector integration at the Mds1/Evi1 locus in nonhuman primate hematopoietic cells.
abstract: Recent reports linking insertional activation of LMO2 following gene therapy for X-linked severe combined immunodeficiency (X-SCID) have led to a re-evaluation of risks following gene therapy with retroviral vectors. In our analysis of 702 integration sites in rhesus macaques that underwent transplantation up to 7 years earlier with autologous CD34+ cells transduced with amphotropic murine leukemia virus (MLV)-derived retroviral vectors containing marker genes, we detected insertion into one locus, the Mds1/Evi1 region, a total of 14 times in 9 animals. Mds1/Evi1 integrations were observed stably long term, primarily in myeloid cells. We hypothesize that this over-representation likely results from an impact on the self-renewal and engraftment potential of CD34+ progenitor cells via insertional mutagenesis at this specific locus. There is no evidence of ongoing in vivo clonal expansion of the Mds1/Evi1 populations, and all animals are hematologically normal without evidence for leukemia. Characterization of integration sites in this relevant preclinical model provides critical information for gene therapy risk assessment as well as identification of genes controlling hematopoiesis.
authors.affiliation: Hematology Branch, National Heart, Lung, and Blood Institute, Bethesda, MD, USA.
authors.forename: Boris
authors.initials: B
authors.lastname: Calmels
authors.forename: Cole
authors.initials: C
authors.lastname: Ferguson
authors.forename: Mikko O
authors.initials: MO
authors.lastname: Laukkanen
authors.forename: Rima
authors.initials: R
authors.lastname: Adler
authors.forename: Marion
authors.initials: M
authors.lastname: Faulhaber
authors.forename: Hyeoung-Joon
authors.initials: HJ
authors.lastname: Kim
authors.forename: Stephanie
authors.initials: S
authors.lastname: Sellers
authors.forename: Peiman
authors.initials: P
authors.lastname: Hematti
authors.forename: Manfred
authors.initials: M
authors.lastname: Schmidt
authors.forename: Christof
authors.initials: C
authors.lastname: von Kalle
authors.forename: Keiko
authors.initials: K
authors.lastname: Akagi
authors.forename: Robert E
authors.initials: RE
authors.lastname: Donahue
authors.forename: Cynthia E
authors.initials: CE
authors.lastname: Dunbar
mesh_terms: D000818:Animals; D018952:Antigens, CD34 / Q000096:biosynthesis; D004268:DNA-Binding Proteins / Q000235:genetics*; D018450:Disease Progression; D015316:Genetic Therapy / Q000379:methods; D005822:Genetic Vectors; D006098:Granulocytes / Q000166:cytology; D006410:Hematopoiesis; D006412:Hematopoietic Stem Cells / Q000378:metabolism*; D006801:Humans; D007938:Leukemia / Q000235:genetics; D009052:Leukemia Virus, Murine / Q000235:genetics; D007963:Leukocytes, Mononuclear / Q000166:cytology; D000074008:MDS1 and EVI1 Complex Locus Protein; D008253:Macaca mulatta; D016254:Mutagenesis, Insertional; D011323:Primates; D011519:Proto-Oncogenes / Q000235:genetics*; D012190:Retroviridae / Q000235:genetics*; D012306:Risk; D013234:Stem Cells; D013997:Time Factors; D014157:Transcription Factors / Q000235:genetics*
chemical_list: D018952:Antigens, CD34; D004268:DNA-Binding Proteins; D000074008:MDS1 and EVI1 Complex Locus Protein; C063575:MECOM protein, human; D014157:Transcription Factors