Ortho-Hydroxyanilides: Slow-Acting, Selective Histone Deacetylase 1/2 Inhibitors Suitable for Photocaging...

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.