Cited by 713Histone Deacetylase Inhibitors ResearchEnzyme Structure and FunctionEnzyme function and inhibition

The DOI matches its Crossref record; 23 of the 23 references it cites were found in a registry or an index; none of the 5 sources its claims cite is checked for support yet.

Crystal structure of a eukaryotic zinc-dependent histone deacetylase, human HDAC8, complexed with a hydroxamic acid inhibitor

Open access

Abstract

Histone deacetylases (HDACs) are a family of enzymes involved in the regulation of gene expression, DNA repair, and stress response. These processes often are altered in tumors, and HDAC inhibitors have had pronounced antitumor activity with promising results in clinical trials. Here, we report the crystal structure of human HDAC8 in complex with a hydroxamic acid inhibitor. Such a structure of a eukaryotic zinc-dependent HDAC has not be described previously. Similar to bacterial HDAC-like protein, HDAC8 folds in a single α/β domain. The inhibitor and the zinc-binding sites are similar in both proteins. However, significant differences are observed in the length and structure of the loops surrounding the active site, including the presence of two potassium ions in HDAC8 structure, one of which interacts with key catalytic residues. CD data suggest a direct role of potassium in the fold stabilization of HDAC8. Knockdown of HDAC8 by RNA interference inhibits growth of human lung, colon, and cervical cancer cell lines, highlighting the importance of this HDAC subtype for tumor cell proliferation. Our findings open the way for the design and development of selective inhibitors of HDAC8 as possible antitumor agents.

Overview

AI snapshot

Written from the paper’s full text.

TL;DR

The paper reports the crystal structure of human HDAC8, a eukaryotic zinc-dependent histone deacetylase, in complex with a hydroxamic acid inhibitor, revealing a single α/β domain, a pentacoordinated active-site Zn²⁺, and two bound K⁺ ions. It also shows that HDAC8 has a distinct inhibitor profile and that siRNA knockdown of HDAC8 inhibits proliferation of A549, HeLa, and HCT116 tumor cell lines.

Key findings

  • The HDAC8 monomer folds as a single compact α/β domain with a central eight-stranded parallel β-sheet and 11 α-helices; the crystal contains a head-to-head dimer burying ≈1,300 Ų, but size-exclusion chromatography and light scattering are compatible with a monomer in solution. The active-site Zn²⁺ is pentacoordinated by Asp-178, His-180, Asp-267, and the hydroxamate inhibitor.
  • Two K⁺ sites were identified: site 1 is 7.0 Å from the zinc site and site 2 is 15 Å from site 1, with peaks of 19σ and 13σ, respectively. K⁺ site 1 contacts backbone carbonyls of Asp-178 and His-180, whose side chains coordinate zinc. CD spectroscopy showed a melting midpoint of ≈35.5°C in NaCl versus ≈41°C in KCl.
  • HDAC8 inhibition differed from HDAC1 and HDAC3: IC₅₀ values for HDAC8/HDAC1/HDAC3 were TSA 490/1.5/0.6 nM, SAHA 4,000/119/106 nM, Compound 1 175.5/86.0/44 nM, MS27-275 >10,000/185/201 nM, and apicidin >1,000/2/0.7 nM. Compound 1 showed relatively similar potency across all three enzymes (<4-fold differences).
  • Two HDAC8 siRNAs inhibited proliferation in A549, HeLa, and HCT116 cells; an Eg5 siRNA gave comparable growth inhibition, whereas an unrelated Luc siRNA had no effect.

Methods

  • Human HDAC8 was expressed and purified, then crystallized after incubation of 130 μM HDAC8 with a 6.7 molar excess of inhibitor for 1 h at room temperature. Crystals were grown by sitting-drop vapor diffusion; data were collected at 100 K using synchrotron radiation.
  • The structure was solved by molecular replacement using a truncated homology model of HDAC8 residues 63–320 based on the HDLP–TSA structure (PDB 1C3R), and refined to 2.5 Å with final R and R_free of 0.21 and 0.25.
  • CD spectroscopy measured thermal unfolding in KCl- or NaCl-containing buffers. siRNA transfection and cell-growth assays were performed in A549, HeLa, and HCT116 cells; HDAC inhibition assays tested HDAC1, HDAC3, and HDAC8 against a panel of inhibitors.

Limitations

  • The paper states no formal limitations section. It notes that the crystal dimer is mediated by the inhibitor and is unlikely to occur in solution, and that the relevance of potassium-binding site 2 for catalytic activity is not obvious from the structure.
  • Evident from the text: the structural conclusions come from one 2.5-Å crystal form; potassium-binding site 1 was identified at 75 mM K⁺ in the crystallization drop, lower than the intracellular physiological value of ≈150 mM; and the RNAi proliferation data are limited to three human tumor cell lines with no in vivo results.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1073/pnas.0404603101

Cites

23 of 23 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Verification

Claims the paper makes

0 of 5 cited sources checked · 0 supported · 0 flagged

Show all 45 claims

  • Probably not a substantial claim. 6
  • It may state two separate claims as one. 22
  • The quote only partly states this claim. 1
27 of 27
  • The paper relies on this without support.

    No structure of a eukaryotic zinc-dependent HDAC had been described before this study.

    “Such a structure of a eukaryotic zinc-dependent HDAC has not be described previously.”
  • The paper relies on this without support.

    The dimeric arrangement seen in the crystal has not been found in solution.

    “given that the dimeric arrangement seen in the crystal has not been found in solution”
  • The paper relies on this without support.

    The intracellular physiological K+ concentration is approximately 150 mM.

    “a value lower than its intracellular physiological value of ≈150 mM”
3 of 3

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • HDAC8 is both described as having Ala and included among enzymes with Pro at the same position

    Minor

    The paper identifies Ala-32 in HDAC8 as equivalent to Pro-22 in HDLP, then says that all class I and II HDACs except HDAC10 have Pro at that position. HDAC8 is identified elsewhere in the paper as a class I HDAC.

1 of 1

Citations

Cites

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Show all 23 references

Research works printed but not linked: 1

  1. Somoza, J. R., Skene, R. J., Katz, B. A., Mol, C., Ho, J. D., Jennings, A. J., Luong, C., Arvai, A., Buggy, J. J., Chi, E., et al. (2004) Structure 7, 1325–1334.

Cited by

Sorted by citations

Items 401–500 of 713

Metadata

Authors
Vannini, A., Volpari, C., Filocamo, G., Casavola, E. C., Brunetti, M., Renzoni, D., Chakravarty, P., Paolini, C., De Francesco, R., Gallinari, P., Steinkühler, C., & Di Marco, S.
Affiliations
  • Merck & Co., Inc., Rahway, NJ, USA (United States) (US)
  • Department of Biochemistry, Istituto di Ricerche di Biologia Molecolare P. Angeletti, 00040 Pomezia, Rome, Italy; and Department of Medicinal Chemistry, Merck and Company, Inc., Rahway, NJ 07065
Venue
Proceedings of the National Academy of Sciences
Published
2004-10-11
Volume
101
Issue
42
Pages
15064-15069
ISSN
  • 0027-8424 (ISSN-L)
  • 1091-6490
OpenAlex
W2078454854
Cited by
638
References
23
Citations by year
2026: 19 · 2025: 13 · 2024: 25 · 2023: 17 · 2022: 18 · 2021: 19 · 2020: 23 · 2019: 27 · 2018: 20 · 2017: 27 · 2016: 34 · 2015: 37 · 2014: 30 · 2013: 34 · 2012: 40
FWCI
9.87
Type
journal article
Language
en
Open access
Locations
  • Proceedings of the National Academy of Sciences (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
  • Archivio Istituzionale della Ricerca (Universita Degli Studi Di Milano) (submittedVersion, other-oa)
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Histone Deacetylase Inhibitors Research
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Structural Biology › Enzyme Structure and Function
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Enzyme function and inhibition
Keywords
HDAC8, histone deacetylase, hydroxamate inhibitors, zinc metalloenzyme, crystal structure, potassium ions, active site, anticancer agents, histone deacetylase inhibitors, tumor cell proliferation, RNAi knockdown
MeSH terms
Amino Acid Sequence, Antineoplastic Agents, Circular Dichroism, Enzyme Inhibitors, Histone Deacetylases, Humans, Hydroxamic Acids, Models, Molecular, Molecular Sequence Data, Potassium, Protein Conformation, Recombinant Proteins, Repressor Proteins, Zinc, Drug Design, Sequence Homology, Amino Acid, Crystallography, X-Ray, Catalytic Domain, RNA Interference, Cell Line, Tumor, Histone Deacetylase Inhibitors, In Vitro Techniques

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