Ophiobolin A Covalently Targets Complex IV Leading to Mitochondrial Metabolic Collapse in Cancer Cells

Area of Science:

• Biochemistry
• Molecular Biology
• Cancer Research

Background:

• Ophiobolin A (OPA) is a fungal sesterterpenoid with known anti-cancer properties.
• Its precise proteome-wide targets and anticancer mechanisms remain largely unelucidated.
• OPA's electrophilic nature suggests covalent interactions with proteins.

Approach:

• Utilized covalent chemoproteomic platforms to identify OPA's protein targets in lung cancer cells.
• Focused on HIG2DA (cysteine C53) and COX5A (lysine K72) as key OPA-binding proteins.
• Investigated the functional consequences of OPA engagement with these targets.

Key Points:

• OPA covalently binds to specific residues in HIG2DA and COX5A, components of mitochondrial Complex IV.
• OPA-mediated Complex IV activation initially boosts mitochondrial respiration and ATP production.
• Sustained activation leads to mitochondrial membrane potential collapse and subsequent ATP depletion.

Conclusions:

• Discovered a unique anti-cancer mechanism for Ophiobolin A involving mitochondrial Complex IV.
• OPA induces cell death through compromised mitochondrial energetics and ATP depletion.
• Chemoproteomics provides a powerful strategy for uncovering natural product mechanisms of action.