Highly Selective MERTK Inhibitors Achieved by a Single Methyl Group.

Area of Science:

• Medicinal Chemistry
• Oncology
• Pharmacology

Background:

• Kinase inhibitors target the ATP binding pocket, but selectivity remains a challenge due to conserved residues.
• MERTK and FLT3 are kinases implicated in various cancers, making them attractive therapeutic targets.

Purpose of the Study:

• To design and synthesize novel MERTK inhibitors with enhanced selectivity over FLT3.
• To evaluate the in vitro and in vivo efficacy of a lead compound (Compound 19) as a potential anti-cancer therapeutic.

Main Methods:

• Structure-based drug design incorporating a methyl group to modulate kinase selectivity.
• In vitro biochemical assays to determine inhibitor potency and selectivity (IC50 values).
• Cell-based assays using human cancer cell lines to confirm target engagement and efficacy.
• Pharmacokinetic studies in mice and in vivo assessment of MERTK phosphorylation in leukemia cells.

Main Results:

• A single methyl group significantly enhanced MERTK inhibitor selectivity over FLT3 by up to 1000-fold (Compound 31).
• Compound 19 exhibited subnanomolar activity against MERTK with 38-fold selectivity over FLT3 in vitro.
• Compound 19 demonstrated potent MERTK inhibition in cancer cell lines and favorable pharmacokinetic properties in mice.
• In vivo, Compound 19 treatment reduced MERTK phosphorylation by 75% in bone marrow leukemia cells.

Conclusions:

• Selective MERTK inhibition can be achieved through strategic modifications of ATP-competitive inhibitors.
• Compound 19 is a promising tool compound for further investigation in MERTK-driven cancers.
• The findings support the development of selective MERTK inhibitors for therapeutic applications in oncology.