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Updated: Jul 21, 2025
Deciphering the Structural Effects of Activating EGFR Somatic Mutations with Molecular Dynamics Simulation
Published on: May 20, 2020
Cell-active, irreversible covalent inhibitors that selectively target the catalytic lysine of EGFR by using
Guanghui Tang1, Wei Wang2, Xuan Wang2
1Department of Chemistry, National University of Singapore, Singapore, 117543, Singapore.
Abstract:
EGFR signaling is involved in multiple cellular processes including cell proliferation, differentiation and development, making this protein kinase one of the most valuable drug targets for the treatment of non-small cell lung carcinomas (NSCLC). Herein, we describe the design and synthesis of a series of potential covalent inhibitors targeting the catalytically conserved lysine (K745) of EGFR on the basis of Erlotinib, an FDA-approved first-generation EGFR drug. Different amine-reactive electrophiles were introduced at positions on the Erlotinib scaffold proximal to K745 in EGFR. The optimized compound 26 (as well as its close analog 30), possessing a novel arylfluorosulfate group (ArOSO2F), showed excellent in vitro potency (as low as 0.19 nM in independent IC50 determination) and selectivity against EGFR and many of its drug-resistant mutants. Both intact protein mass spectrometry (MS) and site-mapping analysis revealed that compound 26 covalently bound to EGFR at K745 through the formation of a sulfamate. In addition, compound 26 displayed good anti-proliferative potency against EGFR-overexpressing HCC827 cells by inhibiting endogenous EGFR autophosphorylation. The pharmacokinetic studies of compound 26 demonstrated the druggable potential of other ArOSO2F-containing compounds. Finally, competitive activity-based protein profiling (ABPP), cellular thermal shift assay (CETSA), as well as cellular wash-out experiments, all showed compound 26 to be the first cell-active, fluorosulfate-based targeted covalent inhibitor (TCI) of protein kinases capable of covalently engaging the catalytically conserved lysine of its target in live mammalian cells.
Insights
Researchers developed novel covalent inhibitors targeting EGFR (Epidermal Growth Factor Receptor) for non-small cell lung cancer. Compound 26, a fluorosulfate-based inhibitor, demonstrated potent and selective EGFR inhibition in vitro and in cells.
Area of Science:
- Medicinal Chemistry
- Molecular Biology
- Oncology
Background:
- Epidermal Growth Factor Receptor (EGFR) signaling is crucial for cell growth and is a key target in non-small cell lung cancer (NSCLC).
- Erlotinib is an FDA-approved EGFR inhibitor, but resistance mechanisms necessitate novel therapeutic strategies.
- Targeting the catalytically conserved lysine (K745) offers a unique approach for covalent inhibition of EGFR.
Purpose of the Study:
- To design and synthesize novel covalent inhibitors of EGFR based on the Erlotinib scaffold.
- To identify inhibitors that target the K745 residue of EGFR.
- To evaluate the in vitro and cellular activity of these novel compounds against EGFR and its mutants.
Main Methods:
- Structure-based drug design and chemical synthesis of Erlotinib analogs with amine-reactive electrophiles.
- In vitro biochemical assays to determine inhibitory potency (IC50) and selectivity against EGFR.
- Mass spectrometry (MS) for covalent binding confirmation and site-mapping.
- Cell-based assays to assess anti-proliferative effects and target engagement (autophosphorylation inhibition).
- Pharmacokinetic studies and cellular assays (ABPP, CETSA, wash-out) to evaluate drug-like properties and in vivo potential.
Main Results:
- A series of novel covalent inhibitors were synthesized, incorporating an arylfluorosulfate (ArOSO2F) group.
- Compound 26 exhibited potent in vitro activity (IC50 as low as 0.19 nM) and selectivity against EGFR and resistant mutants.
- Mass spectrometry confirmed covalent binding of compound 26 to K745 of EGFR, forming a sulfamate linkage.
- Compound 26 effectively inhibited EGFR autophosphorylation and proliferation in EGFR-overexpressing cancer cells (HCC827).
- Pharmacokinetic studies indicated druggable potential for ArOSO2F compounds.
Conclusions:
- Compound 26 is the first cell-active, fluorosulfate-based targeted covalent inhibitor (TCI) of protein kinases.
- It effectively targets the conserved K745 lysine of EGFR in live mammalian cells.
- This class of inhibitors holds promise for treating NSCLC, including cases with drug-resistant EGFR mutations.
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