Induction of gene expression by 5-Aza-2'-deoxycytidine in acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) but not epithelial cells by DNA-methylation-dependent and -independent mechanisms

Leukemia. 2005 Jan;19(1):103-11. doi: 10.1038/sj.leu.2403552.


The methylation inhibitor 5-Aza-2'-deoxycytidine (5-Aza-CdR, decitabine) has therapeutic efficacy in acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). Using microarray analysis, we investigated global changes in gene expression after 5-Aza-CdR treatment in AML. In the AML cell line OCI-AML2, Aza-CdR induced the expression of 81 out of 22 000 genes; 96 genes were downregulated (> or =2-fold change in expression). RT-PCR analysis of 10 randomly selected genes confirmed the changes of expression in AML cells. Similar results were obtained with primary AML and MDS cells after treatment with 5-Aza-CdR ex vivo and in vivo, respectively. In contrast, significantly fewer changes in gene expression and cytotoxicity were detected in normal peripheral blood mononuclear and bone marrow cells or transformed epithelial cells treated with 5-Aza-CdR. Interestingly, only 50.6% of the induced genes contain putative CpG islands in the 5' region. To further investigate the significance of promoter methylation in the induced genes, we analyzed the actual methylation status of randomly selected 5-Aza-CdR-inducible genes. We detected hypermethylation exclusively in the 5' region of the myeloperoxidase (MPO) gene. DNA methylation inversely correlated with MPO expression in newly diagnosed untreated AML patients (P< or =0.004). In contrast, all other analyzed 5-Aza-CdR-inducible genes revealed no CpG methylation in the promoter region, suggesting a methylation-independent effect of 5-Aza-CdR.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acute Disease
  • Apoptosis / drug effects
  • Azacitidine / analogs & derivatives*
  • Azacitidine / pharmacology*
  • Base Sequence
  • Cell Division / drug effects
  • DNA Methylation*
  • DNA Primers
  • Decitabine
  • Epithelial Cells / drug effects
  • Gene Expression Regulation, Neoplastic / drug effects*
  • Humans
  • Leukemia, Myeloid / genetics*
  • Leukemia, Myeloid / pathology
  • Myelodysplastic Syndromes / genetics*
  • Myelodysplastic Syndromes / pathology
  • Polymerase Chain Reaction


  • DNA Primers
  • Decitabine
  • Azacitidine