Related Experiment Video
Updated: Jan 8, 2026
Assays for Validating Histone Acetyltransferase Inhibitors
Published on: August 6, 2020
Ortho-Hydroxyanilides: Slow-Acting, Selective Histone Deacetylase 1/2 Inhibitors Suitable for Photocaging
Irina Honin1, Tao Sun1, Nisha Setia1
1Department of Pharmaceutical and Cell Biological Chemistry, Pharmaceutical Institute, University of Bonn, An der Immenburg 4, 53121 Bonn, Germany.
Abstract:
Histone deacetylases (HDACs) regulate gene expression and are promising targets in oncology. Especially the class I isoforms HDAC1 and HDAC2 are overexpressed in cancer. However, while ortho-aminoanilides with a suitable (het)-aryl substitution are well-characterized HDAC1/HDAC2 inhibitors, the corresponding phenol analogs have not been sufficiently investigated so far. To this end, we compared the ortho-hydroxyanilide derivative ST13 with the pan-HDAC inhibitor vorinostat and Cpd-60, an ortho-aminoanilide with high HDAC1/HDAC2 selectivity. ST13 was further developed into a light-activatable prodrug (ST17) by masking its zinc-binding group with a photoremovable 4,5-dimethoxy-2-nitrobenzyl protecting group. Overall, we verified that ST13 is a selective, slow- and tight-binding HDAC1/HDAC2 inhibitor with antiproliferative activity. Furthermore, we demonstrated that the light-activatable prodrug ST17 readily releases ST13 upon irradiation, thereby allowing to precisely control its antiproliferative properties. These findings validate ortho-hydroxyanilides as effective HDAC1/HDAC2-selective inhibitors and highlight photocaging as a promising strategy to achieve spatiotemporal control of epigenetic therapies in cancer.
Insights
Researchers developed ST13, a selective inhibitor targeting histone deacetylases (HDACs) 1 and 2, showing antiproliferative effects. A light-activatable prodrug, ST17, precisely controls these effects, offering a new strategy for epigenetic cancer therapy.
Area of Science:
- Epigenetics and Molecular Oncology
- Drug Discovery and Development
Background:
- Histone deacetylases (HDACs) regulate gene expression and are key targets in cancer therapy.
- Class I HDACs, specifically HDAC1 and HDAC2, are frequently overexpressed in various cancers.
- While ortho-aminoanilides are known HDAC1/HDAC2 inhibitors, ortho-hydroxyanilides remain less explored.
Purpose of the Study:
- To investigate the potential of ortho-hydroxyanilide derivatives as selective HDAC1/HDAC2 inhibitors.
- To develop a light-activatable prodrug for spatiotemporal control of HDAC inhibition.
- To validate ortho-hydroxyanilides and photocaging strategies for epigenetic cancer therapy.
Main Methods:
- Comparison of the ortho-hydroxyanilide ST13 with known HDAC inhibitors (vorinostat, Cpd-60).
- Development of ST17, a photocaged prodrug of ST13 using a photoremovable protecting group.
- Assessment of ST13's binding kinetics (slow- and tight-binding) and antiproliferative activity.
- Evaluation of ST17's light-induced release of ST13 and its controlled antiproliferative effects.
Main Results:
- ST13 demonstrated selective, slow- and tight-binding inhibition of HDAC1 and HDAC2.
- ST13 exhibited significant antiproliferative activity.
- The prodrug ST17 successfully released ST13 upon light irradiation.
- ST17 allowed for precise spatiotemporal control over the antiproliferative effects of ST13.
Conclusions:
- Ortho-hydroxyanilides represent a validated class of selective HDAC1/HDAC2 inhibitors.
- Photocaging is a viable strategy for achieving spatiotemporal control in epigenetic cancer therapies.
- The developed compounds and strategy hold promise for targeted cancer treatment.
Related Concept Videos
01:18Indirect-Acting Cholinergic Agonists: Mechanism of Action
Reversible inhibitors like edrophonium bind to a specific part of the enzyme called the anionic catalytic site. They form noncovalent bonds, which means they are not strongly attached to the enzyme. This creates a temporary and less stable enzyme–inhibitor complex,...
01:29Indirect-Acting Cholinergic Agonists: Chemistry and Structure-Activity Relationship
Reversible inhibitors display short to medium durations of action. Short-acting agents include simple alcohols with...