Lysine deacetylase inhibitors have low selectivity in cells and exhibit predominantly off‐target effects

Lysine deacetylases (KDACs or HDACs) are metal‐dependent enzymes that regulate lysine acetylation, a post‐translational modification that is present on thousands of human proteins, essential for many cellular processes, and often misregulated in diseases. The selective inhibition of KDACs would allo...

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Main Authors: Kiara E. Bornes, Marcus A. Moody, Thomas M. Huckaba, Megan C. Benz, Emily C. McConnell, Maryam Foroozesh, Van H. Barnes, Bridgette M. Collins‐Burow, Matthew E. Burow, Terry J. Watt, Tasha B. Toro
Format: Article
Language:English
Published: Wiley 2025-01-01
Series:FEBS Open Bio
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Online Access:https://doi.org/10.1002/2211-5463.13896
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author Kiara E. Bornes
Marcus A. Moody
Thomas M. Huckaba
Megan C. Benz
Emily C. McConnell
Maryam Foroozesh
Van H. Barnes
Bridgette M. Collins‐Burow
Matthew E. Burow
Terry J. Watt
Tasha B. Toro
author_facet Kiara E. Bornes
Marcus A. Moody
Thomas M. Huckaba
Megan C. Benz
Emily C. McConnell
Maryam Foroozesh
Van H. Barnes
Bridgette M. Collins‐Burow
Matthew E. Burow
Terry J. Watt
Tasha B. Toro
author_sort Kiara E. Bornes
collection DOAJ
description Lysine deacetylases (KDACs or HDACs) are metal‐dependent enzymes that regulate lysine acetylation, a post‐translational modification that is present on thousands of human proteins, essential for many cellular processes, and often misregulated in diseases. The selective inhibition of KDACs would allow for understanding of the biological roles of individual KDACs and therapeutic targeting of individual enzymes. Recent studies have suggested that purportedly specific KDAC inhibitors have significant off‐target binding, but the biological consequences of off‐target binding were not evaluated. We compared the effects of treatment with two of the reportedly most KDAC‐selective inhibitors, Tubastatin A and PCI‐34051, in HT1080 cells in which the endogenous KDAC6 or KDAC8 gene has been mutated to inactivate enzyme catalysis while retaining enzyme expression. Genetic inactivation results in much stronger deacetylation defects on known targets compared to inhibitor treatment. Gene expression analysis revealed that both inhibitors have extensive and extensively overlapping off‐target effects in cells, even at low inhibitor doses. Furthermore, Tubastatin A treatment led to increased histone acetylation, while inactivation of KDAC6 or KDAC8 did not. Genetic inactivation of KDAC6, but not KDAC8, impaired tumor formation in a xenograft model system, in contrast to previous reports with KDAC inhibitors suggesting the reverse. We conclude that the majority of observed biological effects of treatment with KDAC inhibitors are due to off‐target effects rather than the intended KDAC inhibition. Developing a truly specific KDAC6 inhibitor could be a promising therapeutic avenue, but it is imperative to develop new inhibitors that selectively mimic genetic inactivation of individual KDACs.
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spelling doaj-art-2b0a8d5f4aa142abbad2c69f8adc78082025-01-07T02:27:34ZengWileyFEBS Open Bio2211-54632025-01-011519410710.1002/2211-5463.13896Lysine deacetylase inhibitors have low selectivity in cells and exhibit predominantly off‐target effectsKiara E. Bornes0Marcus A. Moody1Thomas M. Huckaba2Megan C. Benz3Emily C. McConnell4Maryam Foroozesh5Van H. Barnes6Bridgette M. Collins‐Burow7Matthew E. Burow8Terry J. Watt9Tasha B. Toro10Department of Chemistry Xavier University of Louisiana New Orleans LA USATulane University School of Medicine New Orleans LA USADepartment of Biology Xavier University of Louisiana New Orleans LA USATulane University School of Medicine New Orleans LA USATulane University School of Medicine New Orleans LA USADepartment of Chemistry Xavier University of Louisiana New Orleans LA USATulane University School of Medicine New Orleans LA USATulane University School of Medicine New Orleans LA USATulane University School of Medicine New Orleans LA USADepartment of Chemistry Xavier University of Louisiana New Orleans LA USADepartment of Chemistry Xavier University of Louisiana New Orleans LA USALysine deacetylases (KDACs or HDACs) are metal‐dependent enzymes that regulate lysine acetylation, a post‐translational modification that is present on thousands of human proteins, essential for many cellular processes, and often misregulated in diseases. The selective inhibition of KDACs would allow for understanding of the biological roles of individual KDACs and therapeutic targeting of individual enzymes. Recent studies have suggested that purportedly specific KDAC inhibitors have significant off‐target binding, but the biological consequences of off‐target binding were not evaluated. We compared the effects of treatment with two of the reportedly most KDAC‐selective inhibitors, Tubastatin A and PCI‐34051, in HT1080 cells in which the endogenous KDAC6 or KDAC8 gene has been mutated to inactivate enzyme catalysis while retaining enzyme expression. Genetic inactivation results in much stronger deacetylation defects on known targets compared to inhibitor treatment. Gene expression analysis revealed that both inhibitors have extensive and extensively overlapping off‐target effects in cells, even at low inhibitor doses. Furthermore, Tubastatin A treatment led to increased histone acetylation, while inactivation of KDAC6 or KDAC8 did not. Genetic inactivation of KDAC6, but not KDAC8, impaired tumor formation in a xenograft model system, in contrast to previous reports with KDAC inhibitors suggesting the reverse. We conclude that the majority of observed biological effects of treatment with KDAC inhibitors are due to off‐target effects rather than the intended KDAC inhibition. Developing a truly specific KDAC6 inhibitor could be a promising therapeutic avenue, but it is imperative to develop new inhibitors that selectively mimic genetic inactivation of individual KDACs.https://doi.org/10.1002/2211-5463.13896HDAC6HDAC8HDACiimmunofluorescenceRNA‐seq
spellingShingle Kiara E. Bornes
Marcus A. Moody
Thomas M. Huckaba
Megan C. Benz
Emily C. McConnell
Maryam Foroozesh
Van H. Barnes
Bridgette M. Collins‐Burow
Matthew E. Burow
Terry J. Watt
Tasha B. Toro
Lysine deacetylase inhibitors have low selectivity in cells and exhibit predominantly off‐target effects
FEBS Open Bio
HDAC6
HDAC8
HDACi
immunofluorescence
RNA‐seq
title Lysine deacetylase inhibitors have low selectivity in cells and exhibit predominantly off‐target effects
title_full Lysine deacetylase inhibitors have low selectivity in cells and exhibit predominantly off‐target effects
title_fullStr Lysine deacetylase inhibitors have low selectivity in cells and exhibit predominantly off‐target effects
title_full_unstemmed Lysine deacetylase inhibitors have low selectivity in cells and exhibit predominantly off‐target effects
title_short Lysine deacetylase inhibitors have low selectivity in cells and exhibit predominantly off‐target effects
title_sort lysine deacetylase inhibitors have low selectivity in cells and exhibit predominantly off target effects
topic HDAC6
HDAC8
HDACi
immunofluorescence
RNA‐seq
url https://doi.org/10.1002/2211-5463.13896
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