Discovery and Mechanism of Small Molecule Inhibitors Selective for the Chromatin-Binding Domains of Oncogenic UHRF1

Area of Science:

• Epigenetics and Molecular Biology
• Cancer Biology
• Drug Discovery

Background:

• Chromatin abnormalities and altered DNA methylation are hallmarks of cancer, often silencing tumor suppressor genes.
• UHRF1 (ubiquitin-like PHD and RING finger domain-containing protein 1) is crucial for establishing and maintaining epigenetic patterns by sensing and reinforcing DNA methylation.
• Existing UHRF1 inhibitors do not block interactions with histones in the full-length protein, limiting their utility.

Purpose of the Study:

• To discover and characterize small molecules that selectively inhibit the interaction between UHRF1 and histones.
• To elucidate the mechanism of action for these novel UHRF1-histone inhibitors.
• To validate the therapeutic potential of targeting the UHRF1-histone interaction.

Main Methods:

• High-throughput screening to identify UHRF1-histone interaction inhibitors.
• Biochemical assays to determine compound potency and mechanism of action.
• In vitro and cellular assays to assess the displacement of full-length UHRF1 from histones.

Main Results:

• Discovery of selective small molecule inhibitors of UHRF1-histone interaction with low micromolar potency.
• Identification of the PHD finger of UHRF1 as the specific target, disrupting histone H3 arginine 2 binding.
• Demonstration that these compounds effectively displace full-length UHRF1 binding to histones in vitro and in cellular models.

Conclusions:

• The PHD finger of UHRF1 plays a critical role in mediating histone interactions.
• Targeting a specific binding pocket within the UHRF1 PHD finger is a viable strategy for inhibiting UHRF1-histone interactions.
• These novel inhibitors provide valuable tools for cancer research and epigenetic studies.