Phenotypic switching as a non-genetic mechanism of resistance predicts antibody therapy regimens

Area of Science:

• Immunology
• Cancer Biology
• Pharmacology

Background:

• Antibody therapy, including cetuximab, is effective but faces treatment resistance.
• Non-genetic mechanisms like epigenetic changes and phenotypic adaptations contribute to resistance, but are not fully understood.
• Understanding these mechanisms is crucial for overcoming resistance in antibody-dependent cellular cytotoxicity (ADCC).

Purpose of the Study:

• To investigate non-genetic resistance mechanisms in colorectal cancer cells against cetuximab-induced ADCC.
• To explore the phenotypic plasticity and reversibility of treatment resistance.
• To develop a predictive model for optimizing antibody therapy dosing strategies.

Main Methods:

• Colorectal cancer cell lines were exposed to cetuximab to select for resistant clones.
• Characterization of resistance mechanisms involved analyzing gene expression (EGFR/HER2) and NK cell activation.
• A mathematical model was developed to simulate phenotypic switching dynamics under therapeutic pressure.

Main Results:

• Resistant clones showed reduced EGFR/HER2 expression and impaired NK cell activation.
• Enrichment of interferon-related pathways was observed in resistant cells.
• Resistance was reversible upon withdrawal of cetuximab, indicating phenotypic plasticity.

Conclusions:

• Colorectal cancer cells can develop reversible, non-genetic resistance to ADCC via phenotypic adaptation.
• Mathematical modeling suggests intermittent dosing as a superior strategy to continuous dosing for delaying resistance.
• Findings offer insights for enhancing efficacy and circumventing resistance in targeted antibody therapies.