Physical insights guided rational design of anti-EGFR antibody to reverse the acquired resistance

Area of Science:

• Biochemistry
• Molecular Biology
• Drug Discovery

Background:

• Cetuximab (Ctx) is an antibody therapy for colorectal cancer targeting the epidermal growth factor receptor (EGFR).
• Acquired resistance due to EGFR mutations diminishes Ctx efficacy.
• Understanding resistance mechanisms is crucial for developing effective treatments.

Purpose of the Study:

• To investigate molecular mechanisms of Ctx resistance driven by EGFR mutations.
• To design Ctx variants that restore binding affinity to resistant EGFR mutants.
• To validate the efficacy of designed Ctx variants in vitro.

Main Methods:

• Molecular dynamics simulations and free energy perturbation calculations to analyze binding interfaces.
• Rational design of Ctx variants using electrostatic compensation and steric hindrance adjustment.
• Surface plasmon resonance and western blot assays to assess binding affinity and cellular efficacy.

Main Results:

• EGFR mutations alter the electrostatic properties of the Ctx binding interface, causing resistance.
• Designed Ctx variants (CtxD103R and CtxD103E_E105D) showed improved binding to EGFR K489E and I491M mutants, respectively.
• CtxD103R effectively inhibited EGF-stimulated phosphorylation of EGFR K489E in cell-based assays.

Conclusions:

• A rational, mechanism-based design approach can overcome antibody resistance in cancer therapy.
• Detailed analysis of molecular interactions enables effective antibody engineering.
• This strategy offers a promising and cost-effective method to combat mutation-driven resistance in antibody therapies.