Nucleosome acidic patch-targeting binuclear ruthenium compounds induce aberrant chromatin condensation

Area of Science:

• Biochemistry
• Molecular Biology
• Chemical Biology

Background:

• The nucleosome acidic patch is crucial for protein interactions and chromatin regulation.
• Targeting this site with drugs offers therapeutic potential but cellular effects are largely unknown.

Purpose of the Study:

• To characterize binuclear ruthenium compounds that selectively target the nucleosome acidic patch.
• To investigate the cellular impact and mechanism of action of these novel compounds.

Main Methods:

• Synthesis and characterization of binuclear ruthenium compounds.
• In vitro assays assessing nucleosome cross-linking, chromatin condensation, and protein binding.
• Cellular assays evaluating cell cycle progression, DNA damage response, and apoptosis induction.

Main Results:

• The ruthenium compounds selectively cross-link H2A-H2B within and between nucleosomes.
• These agents induce an irreversible, anomalous chromatin condensation state.
• Unlike cisplatin or RAPTA-C, they do not cause cell cycle arrest or DNA damage but lead to apoptosis.
• In vitro, they cause chromatin fiber misfolding and inhibit regulator of chromatin condensation 1 (RCC1) binding.

Conclusions:

• Binuclear ruthenium compounds represent a novel class of chromatin-modifying agents.
• Targeting the nucleosome acidic patch can induce apoptosis via chromatin condensation, independent of DNA damage.
• These compounds hold promise for anticancer drug development and as research tools for chromatin biology.