Epigenetic dysregulation of the death-associated protein kinase/p14/HDM2/p53/Apaf-1 apoptosis pathway in multiple myeloma

J Clin Pathol. 2007 Jun;60(6):664-9. doi: 10.1136/jcp.2006.038331.

Abstract

Aim: To study the role of gene promoter hypermethylation of the putative tumour suppressor genes involved in the death-associated protein (DAP) kinase/p14/HDM2/p53/Apaf-1 apoptosis pathway in multiple myeloma (MM).

Method: DNAs from 55 primary MM marrow samples and myeloma cell lines were analysed for aberrant promoter methylation of DAP kinase, p14 and Apaf-1 genes by methylation-specific polymerase chain reaction (MSP).

Result: In the methylated positive control, the sensitivity of M-MSP for DAP kinase was 1 x 10(-3). Aberrant hypermethylation of DAP kinase was found in 29/55 (52.7%) primary MM samples, whereas hypermethylation of p14 or Apaf-1 was undetectable in any of the samples tested. 5-Azacytidine treatment of two myeloma cell lines, WL2 and HS-Sultan, led to de-methylation and re-expression of DAP kinase, thereby confirming gene silencing associated with promoter hypermethylation. Hypermethylation of DAP kinase did not correlate with age, sex, paraprotein subtype or Durie-Salmon stage, but negatively affected the overall survival.

Conclusion: Of the putative tumour suppressor genes in the DAP kinase/p14/HDM2/p53/Apaf-1 apoptosis pathway, only DAP kinase is frequently methylated in MM, which is associated with gene silencing and might be of prognostic significance. p14 and Apaf-1 were not methylated in MM.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Antimetabolites, Antineoplastic / pharmacology
  • Apoptosis Regulatory Proteins / genetics*
  • Apoptotic Protease-Activating Factor 1 / genetics
  • Azacitidine / pharmacology
  • Base Sequence
  • Biomarkers, Tumor / genetics*
  • Calcium-Calmodulin-Dependent Protein Kinases / genetics
  • DNA Methylation / drug effects
  • DNA, Neoplasm / genetics
  • Death-Associated Protein Kinases
  • Epigenesis, Genetic*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Molecular Sequence Data
  • Multiple Myeloma / genetics*
  • Multiple Myeloma / pathology
  • Multiple Myeloma / therapy
  • Neoplasm Proteins / genetics*
  • Polymerase Chain Reaction / methods
  • Prognosis
  • Proto-Oncogene Proteins c-mdm2 / genetics
  • Reverse Transcriptase Polymerase Chain Reaction / methods
  • Survival Analysis
  • Tumor Cells, Cultured
  • Tumor Suppressor Protein p53 / genetics

Substances

  • APAF1 protein, human
  • Antimetabolites, Antineoplastic
  • Apoptosis Regulatory Proteins
  • Apoptotic Protease-Activating Factor 1
  • Biomarkers, Tumor
  • DNA, Neoplasm
  • Neoplasm Proteins
  • Tumor Suppressor Protein p53
  • MDM2 protein, human
  • Proto-Oncogene Proteins c-mdm2
  • Death-Associated Protein Kinases
  • Calcium-Calmodulin-Dependent Protein Kinases
  • Azacitidine