Histone deacetylase 1 gene expression and sensitization of multidrug-resistant neuroblastoma cell lines to cytotoxic agents by depsipeptide

J Natl Cancer Inst. 2007 Jul 18;99(14):1107-19. doi: 10.1093/jnci/djm044. Epub 2007 Jul 10.


Background: Genes that are overexpressed in multidrug-resistant neuroblastomas relative to drug-sensitive neuroblastomas may provide targets for modulating drug resistance.

Methods: We used microarrays to compare the gene expression profile of two drug-sensitive neuroblastoma cell lines with that of three multidrug-resistant neuroblastoma cell lines. RNA expression of selected overexpressed genes was quantified in 17 neuroblastoma cell lines by reverse transcription-polymerase chain reaction (RT-PCR). Small-interfering RNAs (siRNAs) were used for silencing gene expression. Cytotoxicity of melphalan, carboplatin, etoposide, and vincristine and cytotoxic synergy (expressed as combination index calculated by CalcuSyn software, where combination index < 1 indicates synergy and > 1 indicates antagonism) were measured in cell lines with a fluorescence-based assay of cell viability. All statistical tests were two-sided.

Results: A total of 94 genes were overexpressed in the multidrug-resistant cell lines relative to the drug-sensitive cell lines. Nine genes were selected for RT-PCR analysis, of which four displayed higher mRNA expression in the multidrug-resistant lines than in the drug-sensitive lines: histone deacetylase 1 (HDAC1; 2.3-fold difference, 95% confidence interval [CI] = 1.0-fold to 3.5-fold, P = .025), nuclear transport factor 2-like export factor (4.2-fold difference, 95% CI = 1.7-fold to 7.6-fold, P = .0018), heat shock 27-kDa protein 1 (2.5-fold difference, 95% CI = 1.0-fold to 87.7-fold, P = .028), and TAF12 RNA polymerase II, TATA box-binding protein-associated factor, 20 kDa (2.2-fold, 95% CI = 0.9-fold to 6.0-fold, P = .051). siRNA knockdown of HDAC1 gene expression sensitized CHLA-136 neuroblastoma cells to etoposide up to fivefold relative to the parental cell line or scrambled siRNA-transfected cells (P<.001). Cytotoxicity of the histone deacetylase inhibitor depsipeptide was tested in combination with melphalan, carboplatin, etoposide, or vincristine in five multidrug-resistant neuroblastoma cell lines, and synergistic cytotoxicity was demonstrated at a 90% cell kill of treated cells (combination index < 0.8) in all cell lines.

Conclusion: High HDAC1 mRNA expression was associated with multidrug resistance in neuroblastoma cell lines, and inhibition of HDAC1 expression or activity enhanced the cytotoxicity of chemotherapeutic drugs in multidrug-resistant neuroblastoma cell lines. Thus, HDAC1 is a potential therapeutic target in multidrug-resistant neuroblastoma.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylation / drug effects
  • Antineoplastic Agents / pharmacology*
  • Cell Line, Tumor
  • Depsipeptides / pharmacology*
  • Drug Resistance, Multiple / drug effects
  • Drug Resistance, Multiple / genetics*
  • Drug Resistance, Neoplasm / drug effects
  • Drug Resistance, Neoplasm / genetics*
  • Enzyme Inhibitors / pharmacology*
  • Etoposide / pharmacology
  • Gene Expression
  • Gene Expression Profiling
  • Genes, Neoplasm
  • Histone Deacetylase 1
  • Histone Deacetylase Inhibitors
  • Histone Deacetylases / genetics*
  • Histones / metabolism
  • Humans
  • Neuroblastoma / genetics*
  • Oligonucleotide Array Sequence Analysis
  • RNA, Messenger / analysis
  • RNA, Small Interfering / pharmacology


  • Antineoplastic Agents
  • Depsipeptides
  • Enzyme Inhibitors
  • Histone Deacetylase Inhibitors
  • Histones
  • RNA, Messenger
  • RNA, Small Interfering
  • Etoposide
  • HDAC1 protein, human
  • Histone Deacetylase 1
  • Histone Deacetylases