TOX4 and its binding partners recognize DNA adducts generated by platinum anticancer drugs

Area of Science:

• Biochemistry
• Molecular Biology
• Proteomics

Background:

• Platinum-based anticancer drugs, like cisplatin, damage DNA, initiating cellular responses.
• Understanding the proteins that interact with these DNA adducts is crucial for comprehending drug pharmacology and cellular mechanisms like DNA repair and cytotoxicity.

Purpose of the Study:

• To identify and characterize the subproteome of proteins that interact with DNA adducts induced by platinating agents.
• To expand the knowledge of cellular responses to DNA damage caused by chemotherapy.

Main Methods:

• Development of a ligand fishing trap using damaged plasmids attached to magnetic beads.
• Incubation of the trap with cell nuclear extracts and identification of retained proteins using nanoHPLC-tandem mass spectrometry.
• Validation of specific protein-DNA interactions using surface plasmon resonance imaging (SPRi).

Main Results:

• Identification of 38 proteins interacting with DNA adducts generated by cisplatin, oxaliplatin, and satraplatin.
• Confirmation of known interactors such as high mobility group protein 1 (HMGB1) and human upstream binding factor (hUBF).
• Discovery of novel interactors including TOX HMG box family member 4 (TOX4), phosphatase 1 nuclear targeting subunit (PNUTS), and WD repeat-containing protein 82 (WDR82).

Conclusions:

• The study successfully identified a comprehensive list of proteins that bind to DNA damaged by platinating agents.
• Novel protein interactions, particularly with members of a recently discovered complex, suggest new cellular pathways involved in response to chemotherapy-induced DNA damage.
• These findings provide critical insights into the molecular mechanisms underlying the efficacy and toxicity of platinum-based anticancer drugs.