HDAC inhibition is associated to valproic acid induction of early megakaryocytic markers

Exp Cell Res. 2006 May 15;312(9):1590-7. doi: 10.1016/j.yexcr.2006.01.017.


Valproic acid (VPA), a histone deacetylase inhibitor, causes differentiation in different cell lines and in a cell-specific manner; yet, its effect on megakaryocytic (MK) differentiation has not been studied. We evaluated whether VPA induces MK differentiation in a UT-7 cell line through histone acetylation in the GpIIIa gene region and activation of the ERK pathway. UT-7 cells, derived from megakaryoblastic leukemia, were treated with VPA at various concentrations, and the expression of differentiation markers as well as the gene expression profile was assessed. Flow cytometry, immunoblot analysis, and RT-PCR demonstrated that VPA induced the expression of the early MK markers GpIIIa (CD61) and GpIIb/IIIa (CD41) in a dose-dependent manner. The VPA-treated cells showed hyperacetylation of the histones H3 and H4; in particular, histone acetylation was found to have been associated with CD61 expression, in that the GpIIIa promoter showed H4 hyperacetylation, as demonstrated by the chromatin immunoprecipitation assay. Furthermore, activation of the ERK pathway was involved in VPA-mediated CD61/CD41 expression and in cell adhesion, as demonstrated by using the MEK/ERK inhibitor U0126. In conclusion, the capacity of VPA to commit UT-7 cells to MK differentiation is mediated by its inhibitory action on HDAC and the long-lived activation of ERK1/2.

MeSH terms

  • Acetylation / drug effects
  • Butadienes / pharmacology
  • Butyrates / pharmacology
  • Cell Adhesion / drug effects
  • Cell Cycle / drug effects
  • Cell Differentiation / drug effects
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Enzyme Inhibitors / pharmacology
  • Gene Expression / drug effects
  • Histone Deacetylase Inhibitors
  • Histone Deacetylases / metabolism*
  • Histones / metabolism
  • Humans
  • Hydroxamic Acids / pharmacology
  • Integrin beta3 / genetics
  • Integrin beta3 / metabolism
  • Megakaryocytes / cytology
  • Megakaryocytes / drug effects*
  • Megakaryocytes / metabolism
  • Mitogen-Activated Protein Kinase 1 / metabolism
  • Mitogen-Activated Protein Kinase 3 / metabolism
  • Nitriles / pharmacology
  • Phosphorylation / drug effects
  • Platelet Membrane Glycoprotein IIb / metabolism
  • Promoter Regions, Genetic / genetics
  • Valproic Acid / analogs & derivatives
  • Valproic Acid / pharmacology*
  • p38 Mitogen-Activated Protein Kinases / metabolism


  • Butadienes
  • Butyrates
  • Enzyme Inhibitors
  • Histone Deacetylase Inhibitors
  • Histones
  • Hydroxamic Acids
  • ITGB3 protein, human
  • Integrin beta3
  • Nitriles
  • Platelet Membrane Glycoprotein IIb
  • U 0126
  • trichostatin A
  • Valproic Acid
  • Mitogen-Activated Protein Kinase 1
  • Mitogen-Activated Protein Kinase 3
  • p38 Mitogen-Activated Protein Kinases
  • Histone Deacetylases