Abstract
We have identified two new histone deacetylase (HDAC) inhibitors (9 and 24) capable of inducing the expression of γ-globin and/or β-globin promoter-driven reporter genes in a synthetic model of Hb switch. Both compounds also increased, with different mechanisms, the γ/(γ+β) ratio expressed in vitro by normal human erythroblasts. Compound 9 increased the levels of γ-globin mRNA and the γ/(γ+β) ratio (both by 2-fold). Compound 24 increased by 3-fold the level of γ-globin and decreased by 2-fold that of β-globin mRNA, increasing the γ/(γ+β) ratio by 6-fold, and raising (by 50%) the cell HbF content. Both compounds raised the acetylation state of histone H4 in primary cells, an indication that their activity was mediated through HDAC inhibition. Compounds 9 and 24 were also tested as γ/(γ+β) mRNA inducers in erythroblasts obtained from patients with β0 thalassemia. Progenitor cells from patients with β0 thalassemia generated in vitro morphologically normal proerythroblasts that, unlike normal cells, failed to mature in the presence of EPO and expressed low β-globin levels but 10 times higher-than-normal levels of the α hemoglobin-stabilizing protein (AHSP) mRNA. Both compounds ameliorated the impaired in vitro maturation in β0 thalassemic erythroblasts, decreasing AHSP expression to normal levels. In the case of two patients (of five analyzed), the improved erythroblast maturation was associated with detectable increases in the γ/(γ+β) mRNA ratio. The low toxicity exerted by compounds 9 and 24 in all of the assays investigated suggests that these new HDAC inhibitors should be considered for personalized therapy of selected patients with β0 thalassemia.
Footnotes
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This work was partially supported by grants from AIRC 2006 (to A.M.), PRIN 2006038137_005 (to A.M.), PRIN 2006052835_003 (to L.A.); Ministero per l'Università e la Ricerca Scientifica e Tecnologica grants RBNE0189JJ 006, RBNE01sp72 003 (to A.R.M.) and MM06103241 (to G.M.); National Cancer Institute grant P01-CA108671-01A2 (to the Myeloproliferative Disorders Research Consortium); and European Union grant LSHC-CT2005-518417) (to L.A.).
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This work was partially presented as a poster at the annual meeting of the American Society of Hematology in 2004 [Mai A, Massa S, Di Noia A, Jelicic K, Alfani E, Di Rico MC, Di Baldassarre A, Migliaccio AR, and Migliaccio G (2004) Blood104:1216] and as an oral presentation at the annual meeting of the European Hematology Association in 2005 [Di Noia A, Jelicic K, Mai A, Massa S, Di Rico MC, Di Baldassarre A, Alfani E, Migliaccio AR, and Migliaccio G (2005)].
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Article, publication date, and citation information can be found at http://molpharm.aspetjournals.org.
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doi:10.1124/mol.107.036772.
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ABBREVIATIONS: Hb, hemoglobin; HbF, fetal hemoglobin; EPO, erythropoietin; AHSP, α hemoglobin-stabilizing protein; HAT, histone acetyltransferase; HDAC, histone deacetylase; HDACI, histone deacetylase inhibitor; SAHA, suberoylanilide hydroxamic acid; MS-275, pyridin-3-ylmethyl N-[[4-[(2-aminophenyl)carbamoyl]phenyl]methyl]carbamate; APHA, aroyl pyrrolyl hydroxyamide; UBHA, uracil-based hydroxyamide; μLCR, micro locus control region; R, Renilla reniformi; F, firefly; DMSO, dimethyl sulfoxide; AFU, arbitrary fluorescence units; HBSS, Hanks' balanced salt solution; PCR, polymerase chain reaction; IP, immunoprecipitation; HEMA, human erythroblast massive amplification.
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↵ The online version of this article (available at http://molpharm.aspetjournals.org) contains supplemental material.
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↵1 Current affiliation: Mount Sinai School of Medicine, New York, New York.
- Received April 4, 2007.
- Accepted July 25, 2007.
- The American Society for Pharmacology and Experimental Therapeutics
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