Cyclophosphamide promotes engraftment of gene-modified cells in a mouse model of Fanconi anemia without causing cytogenetic abnormalities

J Mol Med (Berl). 2012 Nov;90(11):1283-94. doi: 10.1007/s00109-012-0905-0. Epub 2012 Jun 3.


A major hurdle for hematopoietic stem cell (HSC) gene therapy for inherited bone marrow disorders, including Fanconi anemia (FA), is adequate engraftment of gene-modified cells. A phenotypic defect in DNA repair renders FA patients sensitive to alkylating agents such as cyclophosphamide (Cy); however, at lower doses, Cy is well tolerated in the FA transplant setting. We tested whether non-alkylating agents could replace Cy for pretransplant conditioning to enhance engraftment of FANCA gene-modified hematopoietic cells. We compared Cy preconditioning with fludarabine (Flu) or cytarabine (AraC) or no conditioning as a control in fanca ( -/- ) mutant mice receiving gene-modified bone marrow cells. Only mice conditioned with Cy exhibited appreciable engraftment of gene-modified cells by PCR and resistance to mitomycin C (MMC). Cy administration following transplantation increased gene marking levels in all animals treated, but highest gene marking and corresponding MMC resistance were observed in mice receiving Cy pre- and posttransplantation. Importantly, no cytogenetic abnormalities were observed in Cy-treated mice. We conclude that Cy is an effective and superior preparative regimen with respect to engraftment of lentivirus-transduced cells and functional correction in fanca ( -/- ) mice. Thus, appropriately dosed Cy may provide a suitable conditioning regimen for FA patients undergoing HSC gene therapy.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Bone Marrow Cells
  • Cyclophosphamide / pharmacology*
  • Cytogenetics
  • Disease Models, Animal
  • Fanconi Anemia / genetics*
  • Fanconi Anemia / therapy
  • Flow Cytometry / methods
  • Genetic Therapy / methods
  • HEK293 Cells
  • Hematopoietic Stem Cell Transplantation / methods
  • Humans
  • Lentivirus / genetics
  • Methylcellulose / chemistry
  • Mice
  • Mice, Transgenic
  • Mitomycin / pharmacology
  • Myeloablative Agonists / pharmacology
  • Polymerase Chain Reaction / methods
  • Transplantation Conditioning / methods*


  • Myeloablative Agonists
  • Mitomycin
  • Cyclophosphamide
  • Methylcellulose