title: Targeting AML1/ETO-histone deacetylase repressor complex: a novel mechanism for valproic acid-mediated gene expression and cellular differentiation in AML1/ETO-positive acute myeloid leukemia cells.
abstract: In t(8;21) acute myeloid leukemia (AML), the AML1/ETO fusion protein promotes leukemogenesis by recruiting class I histone deacetylase (HDAC)-containing repressor complex to the promoter of AML1 target genes. Valproic acid (VPA), a commonly used antiseizure and mood stabilizer drug, has been shown to cause growth arrest and induce differentiation of malignant cells via HDAC inhibition. VPA causes selective proteasomal degradation of HDAC2 but not other class I HDACs (i.e., HDAC 1, 3, and 8). Therefore, we raised the question of whether this drug can effectively target the leukemogenic activity of the AML1/ETO fusion protein that also recruits HDAC1, a key regulator of normal and aberrant histone acetylation. We report here that VPA treatment disrupts the AML1/ETO-HDAC1 physical interaction, stimulates the global dissociation of AML1/ETO-HDAC1 complex from the promoter of AML1/ETO target genes, and induces relocation of both AML1/ETO and HDAC1 protein from nuclear to perinuclear region. Furthermore, we show that mechanistically these effects associate with a significant inhibition of HDAC activity, histone H3 and H4 hyperacetylation, and recruitment of RNA polymerase II, leading to transcriptional reactivation of target genes (i.e., IL-3) otherwise silenced by AML1/ETO fusion protein. Ultimately, these pharmacological effects resulted in significant antileukemic activity mediated by partial cell differentiation and caspase-dependent apoptosis. Taken together, these data support the notion that VPA might effectively target AML1/ETO-driven leukemogenesis through disruption of aberrant HDAC1 function and that VPA should be integrated in novel therapeutic approaches for AML1/ETO-positive AML.
authors: Division of Hematology, The Ohio State University, 320 West 10th Avenue, Columbus, OH 43210, USA.
authors: Shujun
authors: S
authors: Liu
authors: Rebecca B
authors: RB
authors: Klisovic
authors: Tamara
authors: T
authors: Vukosavljevic
authors: Jianhua
authors: J
authors: Yu
authors: Peter
authors: P
authors: Paschka
authors: Lenguyen
authors: L
authors: Huynh
authors: Jiuxia
authors: J
authors: Pang
authors: Paolo
authors: P
authors: Neviani
authors: Zhongfa
authors: Z
authors: Liu
authors: William
authors: W
authors: Blum
authors: Kenneth K
authors: KK
authors: Chan
authors: Danilo
authors: D
authors: Perrotti
authors: Guido
authors: G
authors: Marcucci
mesh_terms: D000107:Acetylation / Q000187:drug effects; D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D053148:Caspase 3 / Q000378:metabolism; D053453:Caspase 9 / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects* / Q000235:genetics; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D042002:Chromatin Assembly and Disassembly / Q000187:drug effects; D047369:Chromatin Immunoprecipitation; D050676:Core Binding Factor Alpha 2 Subunit / Q000235:genetics* / Q000378:metabolism; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D004247:DNA / Q000378:metabolism; D015973:Gene Expression Regulation, Leukemic / Q000187:drug effects; D056284:Histone Deacetylase 1; D056464:Histone Deacetylase 2; D056572:Histone Deacetylase Inhibitors; D006655:Histone Deacetylases / Q000378:metabolism*; D006657:Histones / Q000378:metabolism; D006801:Humans; D007377:Interleukin-3 / Q000235:genetics; D015470:Leukemia, Myeloid, Acute / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D015514:Oncogene Proteins, Fusion / Q000235:genetics* / Q000378:metabolism; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011485:Protein Binding / Q000187:drug effects; D012319:RNA Polymerase II / Q000378:metabolism; D000075142:RUNX1 Translocation Partner 1 Protein; D012097:Repressor Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D014635:Valproic Acid / Q000494:pharmacology*
chemical_list: C107844:AML1-ETO fusion protein, human; D000590:Amino Acid Chloromethyl Ketones; D050676:Core Binding Factor Alpha 2 Subunit; D015853:Cysteine Proteinase Inhibitors; D056572:Histone Deacetylase Inhibitors; D006657:Histones; D007377:Interleukin-3; D015514:Oncogene Proteins, Fusion; D000075142:RUNX1 Translocation Partner 1 Protein; D012097:Repressor Proteins; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; D014635:Valproic Acid; D004247:DNA; C499320:PARP1 protein, human; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases; D012319:RNA Polymerase II; D053148:Caspase 3; D053453:Caspase 9; C110550:HDAC1 protein, human; D056284:Histone Deacetylase 1; D056464:Histone Deacetylase 2; D006655:Histone Deacetylases