Monoketone analogs of curcumin, a new class of Fanconi anemia pathway inhibitors

Area of Science:

• Molecular Biology
• Cancer Research
• Drug Discovery

Background:

• The Fanconi anemia (FA) pathway is crucial for DNA repair and exhibits synthetic lethality with ATM mutations common in tumors.
• Inhibiting FANCD2 monoubiquitylation (FANCD2-Ub), a key FA pathway step, may selectively target ATM-deficient cancer cells.
• Curcumin is a known weak inhibitor of FANCD2-Ub, prompting the search for more potent derivatives.

Purpose of the Study:

• To identify curcumin derivatives with enhanced activity and specificity for inhibiting the FA pathway.
• To explore the potential of these derivatives as targeted anticancer agents, especially in the context of ATM deficiency.

Main Methods:

• Screening of monoketone curcumin analogs using a replication-free assay in Xenopus extracts.
• Mechanistic studies to elucidate the molecular targets of active compounds, including IKK inhibition.
• In vitro assays in HeLa cells to assess inhibition of FANCD2-Ub and foci formation.
• Cell survival assays using DNA crosslinking agents and ATM-deficient vs. wild-type cells.

Main Results:

• The curcumin analog EF24 was identified as a potent inhibitor of FANCD2-Ub.
• EF24 inhibits the FA pathway by targeting the NF-kB pathway kinase IKK and shows activity in HeLa cells at nanomolar concentrations.
• EF24 specifically sensitizes FA-competent cells to mitomycin C and demonstrates a synthetic lethal effect with ATM deficiency.
• A related compound, 4H-TTD, was also identified with similar inhibitory activities.

Conclusions:

• Monoketone curcumin analogs are effective inhibitors of the Fanconi anemia pathway.
• These compounds represent a promising new class of targeted anticancer therapeutics.
• The identified compounds offer potential for developing novel cancer treatments, particularly for ATM-mutated cancers.