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Genes are often sheltered from the global histone hyperacetylation induced by HDAC inhibitors.

Halsall J, Gupta V, O'Neill LP, Turner BM, Nightingale KP - PLoS ONE (2012)

Bottom Line: Different gene populations respond to each inhibitor, with as many genes down- as up-regulated.Surprisingly, HDACi rarely induced increased histone acetylation at gene promoters, with most genes examined showing minimal change, irrespective of whether genes were up- or down-regulated.Many genes seem to be sheltered from the global histone hyperacetyation induced by HDACi.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biomedical Research, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom.

ABSTRACT
Histone deacetylase inhibitors (HDACi) are increasingly used as therapeutic agents, but the mechanisms by which they alter cell behaviour remain unclear. Here we use microarray expression analysis to show that only a small proportion of genes (∼9%) have altered transcript levels after treating HL60 cells with different HDACi (valproic acid, Trichostatin A, suberoylanilide hydroxamic acid). Different gene populations respond to each inhibitor, with as many genes down- as up-regulated. Surprisingly, HDACi rarely induced increased histone acetylation at gene promoters, with most genes examined showing minimal change, irrespective of whether genes were up- or down-regulated. Many genes seem to be sheltered from the global histone hyperacetyation induced by HDACi.

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Related in: MedlinePlus

Changes in bulk histone acetylation and cell cycle progression induced by HDACi.(A) Western blots, and (B) quantification of the changes induced in H3K9ac, H4K8ac, H4K16ac abundance upon VPA treatment (5 mM, 8 hours). (C) Triton-acid-urea gel of histones isolated from control (C), or VPA–treated cells over the same time course. Histone H4 associated with none, one or more acetyl residues are indicated. (D) HDACi treatment impacts on the cell cycle. Fluorescence activated cell sorting of untreated and VPA (5 mM), SAHA (2.5 µM) or TSA (165 nM) treated cells (8 hours). Cells associated with distinct stages of the cell cycle are indicated. Cells labelled Sub-G are either dead or apoptotic.
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pone-0033453-g001: Changes in bulk histone acetylation and cell cycle progression induced by HDACi.(A) Western blots, and (B) quantification of the changes induced in H3K9ac, H4K8ac, H4K16ac abundance upon VPA treatment (5 mM, 8 hours). (C) Triton-acid-urea gel of histones isolated from control (C), or VPA–treated cells over the same time course. Histone H4 associated with none, one or more acetyl residues are indicated. (D) HDACi treatment impacts on the cell cycle. Fluorescence activated cell sorting of untreated and VPA (5 mM), SAHA (2.5 µM) or TSA (165 nM) treated cells (8 hours). Cells associated with distinct stages of the cell cycle are indicated. Cells labelled Sub-G are either dead or apoptotic.

Mentions: As a model system for these experiments, we used the human promyeloid leukaemia cell line HL60 [21]. We have shown previously that HL60 cells exposed to HDACi exhibit a rapid increase in histone acetylation, which plateaus after ∼8 hours of treatment [15]. Western blotting with residue-specific antibodies confirmed these data – indicating a rapid response, and similar increases in H3 and H4 acetylation observed after eight hours of HDACi treatment (Fig. 1A,B). Subsequent triton-acid-urea gel analysis confirmed these changes are genome-wide (Fig. 1C), as the bulk of histone H4 is non or mono-acetylated in untreated cells, but ∼80% of histone H4 is acetylated after eight hours of treatment.


Genes are often sheltered from the global histone hyperacetylation induced by HDAC inhibitors.

Halsall J, Gupta V, O'Neill LP, Turner BM, Nightingale KP - PLoS ONE (2012)

Changes in bulk histone acetylation and cell cycle progression induced by HDACi.(A) Western blots, and (B) quantification of the changes induced in H3K9ac, H4K8ac, H4K16ac abundance upon VPA treatment (5 mM, 8 hours). (C) Triton-acid-urea gel of histones isolated from control (C), or VPA–treated cells over the same time course. Histone H4 associated with none, one or more acetyl residues are indicated. (D) HDACi treatment impacts on the cell cycle. Fluorescence activated cell sorting of untreated and VPA (5 mM), SAHA (2.5 µM) or TSA (165 nM) treated cells (8 hours). Cells associated with distinct stages of the cell cycle are indicated. Cells labelled Sub-G are either dead or apoptotic.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3316569&req=5

pone-0033453-g001: Changes in bulk histone acetylation and cell cycle progression induced by HDACi.(A) Western blots, and (B) quantification of the changes induced in H3K9ac, H4K8ac, H4K16ac abundance upon VPA treatment (5 mM, 8 hours). (C) Triton-acid-urea gel of histones isolated from control (C), or VPA–treated cells over the same time course. Histone H4 associated with none, one or more acetyl residues are indicated. (D) HDACi treatment impacts on the cell cycle. Fluorescence activated cell sorting of untreated and VPA (5 mM), SAHA (2.5 µM) or TSA (165 nM) treated cells (8 hours). Cells associated with distinct stages of the cell cycle are indicated. Cells labelled Sub-G are either dead or apoptotic.
Mentions: As a model system for these experiments, we used the human promyeloid leukaemia cell line HL60 [21]. We have shown previously that HL60 cells exposed to HDACi exhibit a rapid increase in histone acetylation, which plateaus after ∼8 hours of treatment [15]. Western blotting with residue-specific antibodies confirmed these data – indicating a rapid response, and similar increases in H3 and H4 acetylation observed after eight hours of HDACi treatment (Fig. 1A,B). Subsequent triton-acid-urea gel analysis confirmed these changes are genome-wide (Fig. 1C), as the bulk of histone H4 is non or mono-acetylated in untreated cells, but ∼80% of histone H4 is acetylated after eight hours of treatment.

Bottom Line: Different gene populations respond to each inhibitor, with as many genes down- as up-regulated.Surprisingly, HDACi rarely induced increased histone acetylation at gene promoters, with most genes examined showing minimal change, irrespective of whether genes were up- or down-regulated.Many genes seem to be sheltered from the global histone hyperacetyation induced by HDACi.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biomedical Research, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom.

ABSTRACT
Histone deacetylase inhibitors (HDACi) are increasingly used as therapeutic agents, but the mechanisms by which they alter cell behaviour remain unclear. Here we use microarray expression analysis to show that only a small proportion of genes (∼9%) have altered transcript levels after treating HL60 cells with different HDACi (valproic acid, Trichostatin A, suberoylanilide hydroxamic acid). Different gene populations respond to each inhibitor, with as many genes down- as up-regulated. Surprisingly, HDACi rarely induced increased histone acetylation at gene promoters, with most genes examined showing minimal change, irrespective of whether genes were up- or down-regulated. Many genes seem to be sheltered from the global histone hyperacetyation induced by HDACi.

Show MeSH
Related in: MedlinePlus