Circumventing the requirement of binding saturation for receptor quantification using interaction kinetic...

Area of Science:

• Biomedical imaging
• Molecular biology
• Biochemistry

Background:

• Accurate quantification of the number of receptors per cell (NRPC) is crucial for evaluating tumor surface biomarkers in medical imaging.
• Traditional binding saturation assays for NRPC are effective but are time-consuming and require substantial reagent quantities.

Purpose of the Study:

• To evaluate kinetic extrapolation (KEX) as an alternative method for NRPC quantification.
• To compare the KEX method with the classical manual saturation technique regarding accuracy, time, and reagent consumption.

Main Methods:

• Quantified epidermal growth factor receptor (EGFR) and HER2 receptor expression on five tumor cell lines.
• Utilized three radiolabeled ligands (cetuximab, EGF, trastuzumab) for both KEX and classical saturation techniques.
• Employed LigandTracer for interaction measurements, followed by KEX analysis for real-time interaction analysis and correction for cell nonsaturation.

Main Results:

• NRPC estimates for EGFR and HER2 using the KEX method were comparable to the classical saturation technique.
• The KEX method demonstrated a significant reduction in ligand consumption, using 26-46% of the amount required by the classical method.
• The KEX method radically reduced the overall workload.

Conclusions:

• The KEX method provides a fast, credible, and user-friendly approach for NRPC quantification.
• This method significantly reduces reagent consumption compared to traditional saturation assays.
• KEX is a promising alternative for assessing tumor biomarker suitability for medical imaging.