title: Mechanism for the decrease in the FIP1L1-PDGFRalpha protein level in EoL-1 cells by histone deacetylase inhibitors.
abstract: BACKGROUND
  Acetylation and deacetylation of proteins occur in cells in response to various stimuli, and are reversibly catalyzed by histone acetyltransferase and histone deacetylase (HDAC), respectively. EoL-1 cells have an FIP1L1-PDGFRA fusion gene that causes transformation of eosinophilic precursor cells into leukemia cells. The HDAC inhibitors apicidin and n-butyrate suppress the proliferation of EoL-1 cells and induce differentiation into eosinophils by a decrease in the protein level of FIP1L1-PDGFRalpha without affecting the mRNA level for FIP1L1-PDGFRA. In this study, we analyzed the mechanism by which the protein level of FIP1L1-PDGFRalpha is decreased by apicidin and n-butyrate.
  
  
  METHODS
  EoL-1 cells were incubated in the presence of the HDAC inhibitors apicidin, trichostatin A or n-butyrate. The protein levels of FIP1L1-PDGFRalpha and phosphorylated eIF-2alpha were determined by Western blotting. Actinomycin D and cycloheximide were used to block RNA synthesis and protein synthesis, respectively, in the chasing experiment of the amount of FIP1L1-PDGFRalpha protein.
  
  
  RESULTS
  When apicidin- and n-butyrate-treated EoL-1 cells were incubated in the presence of actinomycin D, the decrease in the protein level of FIP1L1-PDGFRalpha was significantly enhanced when compared with controls. In contrast, the protein levels were not changed by cycloheximide among these groups. Apicidin and n-butyrate induced the continuous phosphorylation of eIF-2alpha for up to 8 days.
  
  
  CONCLUSIONS
  The decrease in the level of FIP1L1-PDGFRalpha protein by continuous inhibition of HDAC may be due to the decrease in the translation rate of FIP1L1-PDGFRA.
authors.affiliation: Laboratory of Pathophysiological Biochemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan. ishihara@wadalab.mech.tohoku.ac.jp
authors.forename: Kenji
authors.initials: K
authors.lastname: Ishihara
authors.forename: Motoko
authors.initials: M
authors.lastname: Kaneko
authors.forename: Hajime
authors.initials: H
authors.lastname: Kitamura
authors.forename: Aki
authors.initials: A
authors.lastname: Takahashi
authors.forename: Jang Ja
authors.initials: JJ
authors.lastname: Hong
authors.forename: Toshio
authors.initials: T
authors.lastname: Seyama
authors.forename: Koji
authors.initials: K
authors.lastname: Iida
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Wada
authors.forename: Noriyasu
authors.initials: N
authors.lastname: Hirasawa
authors.forename: Kazuo
authors.initials: K
authors.lastname: Ohuchi
mesh_terms: D000107:Acetylation / Q000187:drug effects; D015153:Blotting, Western; D002087:Butyrates / Q000494:pharmacology*; D002454:Cell Differentiation / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D004804:Eosinophils / Q000187:drug effects* / Q000378:metabolism; D015852:Eukaryotic Initiation Factor-2 / Q000032:analysis / Q000187:drug effects / Q000378:metabolism*; D056572:Histone Deacetylase Inhibitors; D006655:Histone Deacetylases / Q000378:metabolism; D006801:Humans; D017681:Hypereosinophilic Syndrome / Q000188:drug therapy* / Q000378:metabolism; D015514:Oncogene Proteins, Fusion / Q000032:analysis* / Q000187:drug effects / Q000378:metabolism; D010456:Peptides, Cyclic / Q000494:pharmacology*; D020796:Receptor, Platelet-Derived Growth Factor alpha / Q000032:analysis* / Q000187:drug effects / Q000378:metabolism; D039221:mRNA Cleavage and Polyadenylation Factors / Q000032:analysis* / Q000187:drug effects / Q000378:metabolism
chemical_list: D002087:Butyrates; D004791:Enzyme Inhibitors; D015852:Eukaryotic Initiation Factor-2; D056572:Histone Deacetylase Inhibitors; D015514:Oncogene Proteins, Fusion; D010456:Peptides, Cyclic; C102351:apicidin; D039221:mRNA Cleavage and Polyadenylation Factors; C479819:FIP1L1-PDGFRA fusion protein, human; D020796:Receptor, Platelet-Derived Growth Factor alpha; D006655:Histone Deacetylases