Modulating Protein-Protein Interactions of the Mitotic Polo-like Kinases to Target Mutant KRAS

Area of Science:

• Oncology
• Molecular Biology
• Drug Discovery

Background:

• Activating mutations in KRAS are common drivers of various cancers.
• KRAS mutations present significant therapeutic challenges due to resistance to current treatments.

Purpose of the Study:

• To develop and evaluate Poloppin, a novel inhibitor targeting Polo-box domain (PBD) mediated protein-protein interactions of Polo-like kinases (PLKs).
• To assess Poloppin's efficacy as a monotherapy and in combination strategies against KRAS-mutant cancers.

Main Methods:

• Biochemical and cellular assays to evaluate Poloppin's target engagement and mechanism of action.
• Assessment of Poloppin's anti-cancer effects in vitro and in vivo using cancer xenograft models.
• Evaluation of resistance development and cross-sensitivity compared to ATP-competitive inhibitors.
• Investigation of Poloppin's sensitizing effects in combination with c-MET inhibitors.

Main Results:

• Poloppin effectively engages PLK PBD targets, inducing mitotic arrest and defective chromosome congression.
• Poloppin selectively kills KRAS-mutant cancer cells, particularly enhancing mitotic cell death.
• An optimized analog, Poloppin-II, demonstrated efficacy in KRAS-expressing cancer xenografts.
• Poloppin exhibited less resistance development and retained cross-sensitivity compared to an ATP-competitive PLK1 inhibitor.
• Poloppin sensitized KRAS-mutant cells to c-MET inhibitors, indicating potential for combination therapy.

Conclusions:

• Poloppin represents a promising therapeutic strategy targeting KRAS-mutant cancers by modulating PLK protein-protein interactions.
• Small molecules targeting PLK PBD interactions offer a viable approach for overcoming therapeutic resistance in KRAS-driven cancers.
• Combination strategies involving Poloppin and agents like c-MET inhibitors may enhance treatment outcomes for patients with KRAS-mutant cancers.