Rhodium metalloinsertor binding generates a lesion with selective cytotoxicity for mismatch repair-deficient cells

Area of Science:

• Molecular Biology
• Cancer Biology
• Medicinal Chemistry

Background:

• The DNA mismatch repair (MMR) pathway is crucial for genomic stability by correcting base pairing errors.
• MMR-deficient cancers are common and exhibit resistance to conventional chemotherapies like cisplatin.
• Targeting MMR-deficient tumors represents a significant clinical need.

Purpose of the Study:

• To elucidate the cellular mechanism of action of a novel rhodium metalloinsertor, Rh-PPO, in MMR-deficient cells.
• To assess the potential of Rh-PPO as a selective chemotherapeutic agent.

Main Methods:

• Characterization of Rh-PPO's interaction with DNA mismatches.
• Investigation of the DNA damage response (DDR) triggered by Rh-PPO.
• Assessment of Rh-PPO's cytotoxicity in MMR-deficient versus MMR-proficient cells.

Main Results:

• Rh-PPO binds specifically to DNA mismatches, inducing a cytotoxic lesion.
• Rh-PPO triggers a robust DDR, leading to cell-cycle arrest and inhibition of DNA/RNA synthesis.
• The induced lesion is unrepaired in MMR-deficient cells, causing selective cell death.

Conclusions:

• Rh-PPO exhibits potent and selective cytotoxicity against MMR-deficient cancer cells.
• Its unique mechanism, involving unrepaired DNA damage, differentiates it from existing chemotherapeutics.
• Rh-PPO holds promise as a targeted therapy for MMR-deficient cancers.