Resistance to cytarabine and gemcitabine and in vitro selection of transduced cells after retroviral expression of cytidine deaminase in human hematopoietic progenitor cells

Leukemia. 2005 Dec;19(12):2281-8. doi: 10.1038/sj.leu.2403977.


Overexpression of the detoxifying enzyme cytidine deaminase (CDD) renders normal and leukemic hematopoietic cells resistant to cytarabine (1-beta-D-arabinofuranosylcytosine), and studies on murine cells have suggested transgenic CDD overexpression as a way to reduce the substantial myelotoxicity induced by the deoxycytidine analogs cytarabine and gemcitabine (2',2'-difluorodeoxycytidine). We now have investigated CDD (over-)expression in the human hematopoietic system. Retroviral gene transfer significantly increased the resistance of CDD-transduced cord blood and peripheral blood-derived progenitor cells for doses ranging from 20-100 nM cytarabine and 8-10 nM gemcitabine. Protection was observed for progenitors of erythroid as well as myeloid differentiation, though the degree of protection varied for individual drugs. In addition, significant selection of CDD-transduced cells was obtained after a 4-day culture in 30-100 nM cytarabine. Thus, our data demonstrate that overexpression of CDD cDNA results in significant protection of human progenitors from cytarabine- as well as gemcitabine-induced toxicity, and allows in vitro selection of transduced cells. This strongly argues for a potential therapeutic role of CDD gene transfer in conjunction with dose-intensive cytarabine- or gemcitabine-containing chemotherapy regimen.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cells, Cultured
  • Cytarabine / pharmacology*
  • Cytidine Deaminase / genetics*
  • Cytidine Deaminase / pharmacology*
  • Deoxycytidine / analogs & derivatives*
  • Deoxycytidine / pharmacology
  • Dose-Response Relationship, Drug
  • Drug Resistance, Multiple / genetics*
  • Erythroid Precursor Cells / metabolism
  • Hematopoietic Stem Cells / metabolism*
  • Humans
  • Myeloid Progenitor Cells / metabolism
  • Retroviridae / genetics
  • Transduction, Genetic


  • Cytarabine
  • Deoxycytidine
  • gemcitabine
  • Cytidine Deaminase