title: Inhibitors of histone deacetylases in class I and class II suppress human osteoclasts in vitro.
abstract: Histone deacetylase inhibitors (HDACi) suppress cancer cell growth, inflammation, and bone resorption. The aim of this study was to determine the effect of inhibitors of different HDAC classes on human osteoclast activity in vitro. Human osteoclasts generated from blood mononuclear cells stimulated with receptor activator of nuclear factor kappa B (RANK) ligand were treated with a novel compound targeting classes I and II HDACs (1179.4b), MS-275 (targets class I HDACs), 2664.12 (targets class II HDACs), or suberoylanilide hydroxamic acid (SAHA; targets classes I and II HDACs). Osteoclast differentiation was assessed by expression of tartrate resistant acid phosphatase and resorption of dentine. Expression of mRNA encoding for osteoclast genes including RANK, calcitonin receptor (CTR), c-Fos, tumur necrosis factor (TNF) receptor associated factor (TRAF)6, nuclear factor of activated T cells (NFATc1), interferon-β, TNF-like weak inducer of apoptosis (TWEAK), and osteoclast-associated receptor (OSCAR) were assessed. Expression of HDACs 1-10 during osteoclast development was also assessed. 1179.4b significantly reduced osteoclast activity (IC(50)  < 0.16 nM). MS-275 (IC(50) 54.4 nM) and 2664.12 (IC(50)  > 100 nM) were markedly less effective. A combination of MS-275 and 2664.12 inhibited osteoclast activity similar to 1179.4b (IC(50) 0.35 nM). SAHA was shown to suppress osteoclast activity (IC(50) 12 nM). 1179.4b significantly (P < 0.05) reduced NFATc1, CTR, and OSCAR expression during the later stages of osteoclast development. Class I HDAC 8 and Class II HDAC5 were both elevated (P < 0.05) during osteoclast development. Results suggest that inhibition of both classes I and II HDACs may be required to suppress human osteoclastic bone resorption in vitro.
authors.affiliation: Discipline of Anatomy and Pathology, School of Medical Sciences, The University of Adelaide, Adelaide, South Australia, Australia.
authors.forename: M D
authors.initials: MD
authors.lastname: Cantley
authors.forename: D P
authors.initials: DP
authors.lastname: Fairlie
authors.forename: P M
authors.initials: PM
authors.lastname: Bartold
authors.forename: K D
authors.initials: KD
authors.lastname: Rainsford
authors.forename: G T
authors.initials: GT
authors.lastname: Le
authors.forename: A J
authors.initials: AJ
authors.lastname: Lucke
authors.forename: C A
authors.initials: CA
authors.lastname: Holding
authors.forename: D R
authors.initials: DR
authors.lastname: Haynes
mesh_terms: D000135:Acid Phosphatase / Q000235:genetics; D001549:Benzamides / Q000494:pharmacology; D001862:Bone Resorption / Q000201:enzymology / Q000473:pathology / Q000517:prevention & control*; D002454:Cell Differentiation / Q000187:drug effects*; D002478:Cells, Cultured; D000074049:Cytokine TWEAK; D003804:Dentin / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005786:Gene Expression Regulation / Q000187:drug effects; D056572:Histone Deacetylase Inhibitors / Q000494:pharmacology*; D006655:Histone Deacetylases / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology; D016899:Interferon-beta / Q000235:genetics; D007527:Isoenzymes / Q000235:genetics; D050778:NFATC Transcription Factors / Q000235:genetics; D010010:Osteoclasts / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D016760:Proto-Oncogene Proteins c-fos / Q000235:genetics; D011725:Pyridines / Q000494:pharmacology; D053245:RANK Ligand / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D053246:Receptor Activator of Nuclear Factor-kappa B / Q000235:genetics; D018003:Receptors, Calcitonin / Q000235:genetics; D011956:Receptors, Cell Surface / Q000235:genetics; D048029:TNF Receptor-Associated Factor 6 / Q000235:genetics; D000071681:Tartrate-Resistant Acid Phosphatase; D013997:Time Factors; D048069:Tumor Necrosis Factors / Q000235:genetics; D000077337:Vorinostat
chemical_list: D001549:Benzamides; D000074049:Cytokine TWEAK; D056572:Histone Deacetylase Inhibitors; D006877:Hydroxamic Acids; D007527:Isoenzymes; D050778:NFATC Transcription Factors; C494003:NFATC1 protein, human; C512828:OSCAR protein, human; D016760:Proto-Oncogene Proteins c-fos; D011725:Pyridines; D053245:RANK Ligand; D012333:RNA, Messenger; D053246:Receptor Activator of Nuclear Factor-kappa B; D018003:Receptors, Calcitonin; D011956:Receptors, Cell Surface; D048029:TNF Receptor-Associated Factor 6; C505686:TNFRSF11A protein, human; C109743:TNFSF12 protein, human; D048069:Tumor Necrosis Factors; C118739:entinostat; D000077337:Vorinostat; D016899:Interferon-beta; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase; D006655:Histone Deacetylases