Indazole-Based Covalent Inhibitors To Target Drug-Resistant Epidermal Growth Factor Receptor

Area of Science:

• Medicinal Chemistry
• Oncology
• Molecular Biology

Background:

• Targeted therapies against oncogenic epidermal growth factor receptor (EGFR) have transformed non-small cell lung cancer (NSCLC) treatment.
• Acquired resistance to existing EGFR inhibitors, particularly through gatekeeper mutations like L858R/T790M, necessitates the development of new therapeutic agents.

Purpose of the Study:

• To optimize a hit compound from a phenotypic screen into potent, selective inhibitors of drug-resistant EGFR mutants.
• To develop novel indazole-based chemical entities capable of overcoming EGFR-mediated resistance in NSCLC.

Main Methods:

• Phenotypic screening to identify hit compounds.
• Structure-activity relationship (SAR) studies and chemical optimization of indazole-based inhibitors.
• Biochemical assays including Western blot analysis, binding kinetics, and kinase selectivity profiling to characterize inhibitor activity and specificity.

Main Results:

• Optimization yielded conformationally constrained indazole-based inhibitors targeting EGFR-L858R/T790M mutations.
• These compounds were shown to covalently alkylate Cys797, a key residue in EGFR.
• Kinase selectivity profiling confirmed the targeted inhibition of drug-resistant EGFR forms.

Conclusions:

• Indazole-based compounds represent a viable chemical scaffold for developing inhibitors against drug-resistant EGFR mutations.
• The optimized inhibitors demonstrate potential as novel therapeutic agents for NSCLC patients with acquired resistance to existing targeted therapies.