title: Hydroxamide derivatives of short-chain fatty acids are potent inducers of human fetal globin gene expression.
abstract: OBJECTIVE
  To examine whether hydroxamic acids are inducers of fetal hemoglobin expression, we tested the effects on gamma gene expression of butyric and propionic hydroxamic acids and of two other hydroxamic acids (SBHA and SAHA), which are potent inhibitors of histone deacetylase (HDAC). We also investigated whether there is a correlation between HDAC inhibitory activity of the compounds and their ability to induce gamma-globin gene expression.
  
  
  METHODS
  Effects on gamma-globin expression were assessed by two methods: 1) a screening assay in which specific gamma-globin gene inducers are recognized by their ability to increase gamma firefly luciferase activity significantly more than beta-renilla luciferase activity; and 2) measurements of gamma-globin mRNA and the frequency of fetal hemoglobin-positive erythroblasts in cultures of burst-forming unit erythroid (BFU-E) from normal individuals. HDAC in vitro activity was measured with a partially purified rat liver HDAC and a fluorogenic substrate.
  
  
  RESULTS
  All compounds tested increased gamma firefly luciferase activity, gamma/gamma+beta mRNA ratios, and percentage of fetal hemoglobin-containing erythroblasts in BFU-E cultures, in a dose-dependent fashion. Butyryl-hydroxamic acid 100 microM increased the gamma/gamma+beta mRNA ratios by 5.8-fold and the frequency of fetal hemoglobin-containing erythroblasts by 4.1-fold. Propionyl-hydroxamic acid 150 microM increased the gamma/gamma+beta ratios by 6.3-fold and the fetal hemoglobin-containing erythroblasts by 3.9-fold. SBHA induced gamma-globin gene expression at very low concentrations, 5 to 20 microM in the luciferase system and 2 to 8 microM in BFU-E cultures; SAHA at 1 to 7.5 microM in the luciferase system and 1 to 2.5 microM in the BFU-E cultures. HDAC in vitro inhibition was observed in the millimolar range for propionate and butyrate. IC(50) determinations led to values of 384 microM for propionyl-hydroxamate, 47 microM for butyryl-hydroxamate, 0.93 microM for SBHA, and 0.26 microM for SAHA. CONCLUCION: Our data indicate that hydroxamic acid-based HDAC inhibitors are potent gamma-globin gene inducers and that the concentration range of their effects on gamma gene expression can be correlated roughly with their HDAC inhibitory potencies.
authors.affiliation: Division of Medical Genetics, University of Washington, Seattle, Wash 98195, USA.
authors.forename: Evangelia
authors.initials: E
authors.lastname: Skarpidi
authors.forename: Hua
authors.initials: H
authors.lastname: Cao
authors.forename: Birgit
authors.initials: B
authors.lastname: Heltweg
authors.forename: Brian F
authors.initials: BF
authors.lastname: White
authors.forename: Ronald L
authors.initials: RL
authors.lastname: Marhenke
authors.forename: Manfred
authors.initials: M
authors.lastname: Jung
authors.forename: George
authors.initials: G
authors.lastname: Stamatoyannopoulos
mesh_terms: D000818:Animals; D001773:Blood Cells; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000138:chemical synthesis / Q000494:pharmacology; D015672:Erythroid Precursor Cells / Q000378:metabolism; D005232:Fatty Acids, Volatile / Q000737:chemistry / Q000494:pharmacology*; D005319:Fetal Hemoglobin / Q000096:biosynthesis / Q000187:drug effects / Q000235:genetics; D005786:Gene Expression Regulation / Q000187:drug effects*; D005914:Globins / Q000096:biosynthesis / Q000187:drug effects* / Q000235:genetics; D056572:Histone Deacetylase Inhibitors; D006801:Humans; D006877:Hydroxamic Acids / Q000737:chemistry / Q000494:pharmacology*; D051379:Mice; D011401:Promoter Regions, Genetic / Q000187:drug effects; D014407:Tumor Cells, Cultured
chemical_list: D004791:Enzyme Inhibitors; D005232:Fatty Acids, Volatile; D056572:Histone Deacetylase Inhibitors; D006877:Hydroxamic Acids; D005914:Globins; D005319:Fetal Hemoglobin