Combination of DNA methylation inhibitor 5-azacytidine and arsenic trioxide has synergistic activity in myeloma

Eur J Haematol. 2009 Mar;82(3):176-83. doi: 10.1111/j.1600-0609.2008.01189.x. Epub 2008 Dec 5.


XAF1 is a newly identified candidate tumour-suppressor gene that can antagonise XIAP and sensitise cells to cell death triggers. This study was undertaken to study the effect of 5-azacytidine (AZA) on XAF1 expression in myeloma cells and efficacy of 5-AZA and arsenic trioxide (ATO) combination treatment in myeloma in vivo and in vitro. XAF1 expression was analysed by semi-quantitative PCR and western blotting. Methylation specific PCR was used to detect methylation status of XAF1 promoter CpG islands. RPMI 8226 and XG-7 cells were treated with various concentrations of 5-AZA and ATO. Expression of XAF1 mRNA variants were confirmed by gel electrophoresis and sequencing. Untreated RPMI 8226 cell expresses two variants of XAF1 mRNA. Untreated XG-7 cell has no expression of XAF1. Hypermethylation of XAF1 promoter CpG islands was detected in both cell lines. Both cell lines express full-length XAF1 transcript after treated with 2.5 mumol/L 5-AZA for 72 h. Our studies demonstrated that 5-AZA exhibits anti-myeloma synergy with ATO. In addition, ATO alone, 5-AZA alone, or combination of 5-AZA and ATO was effective in slowing myeloma growth and prolonging survival of myeloma-loaded nude mice. The findings suggested that 5-AZA and ATO may be an effective combination in the therapy of myeloma patients.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing
  • Animals
  • Apoptosis / drug effects
  • Apoptosis Regulatory Proteins
  • Arsenic Trioxide
  • Arsenicals / pharmacology*
  • Azacitidine / pharmacology*
  • Base Sequence
  • Cell Line, Tumor
  • DNA Methylation / drug effects*
  • Disease Models, Animal
  • Drug Synergism
  • Female
  • Gene Expression Regulation, Neoplastic / drug effects
  • Gene Expression Regulation, Neoplastic / genetics
  • Humans
  • Intracellular Signaling Peptides and Proteins
  • Leukemia, Myeloid / drug therapy*
  • Leukemia, Myeloid / genetics
  • Leukemia, Myeloid / pathology*
  • Mice
  • Mice, Inbred BALB C
  • Mice, Nude
  • Molecular Sequence Data
  • Neoplasm Proteins / genetics
  • Neoplasm Proteins / metabolism
  • Oxides / pharmacology*
  • RNA, Messenger / genetics
  • Transcription, Genetic / drug effects
  • Transcription, Genetic / genetics
  • Xenograft Model Antitumor Assays


  • Adaptor Proteins, Signal Transducing
  • Apoptosis Regulatory Proteins
  • Arsenicals
  • Intracellular Signaling Peptides and Proteins
  • Neoplasm Proteins
  • Oxides
  • RNA, Messenger
  • XAF1 protein, human
  • Azacitidine
  • Arsenic Trioxide