High Affinity Binders to EphA2 Isolated from Abdurin Scaffold Libraries; Characterization, Binding and Tumor...

Area of Science:

• Biotechnology
• Molecular Biology
• Oncology

Background:

• Abdurins are engineered antibody-like scaffolds with prolonged serum half-life due to FcRn binding.
• Ephrin receptor tyrosine kinase class A2 (EphA2) is a cancer target.
• Developing targeted therapies requires high-affinity binders with favorable pharmacokinetics.

Purpose of the Study:

• To construct and screen large libraries for Abdurin binders targeting EphA2.
• To characterize the binding affinity, specificity, and internalization of selected Abdurins.
• To evaluate the in vivo tumor targeting capability of radiolabeled EphA2-specific Abdurins.

Main Methods:

• Construction of phage-display and cell-free DNA display (CIS display) libraries.
• Selection and affinity maturation of Abdurin binders against EphA2.
• In vitro characterization of EphA2 binding and internalization.
• Preclinical in vivo imaging using 64Cu-labeled Abdurins in a prostate cancer xenograft model.

Main Results:

• Isolation of low nanomolar affinity Abdurin binders to human and murine EphA2.
• Demonstrated specific binding to EphA2-expressing cells and rapid internalization.
• PET/CT imaging showed significant tumor localization of 64Cu-labeled anti-EphA2 Abdurins within hours, persisting up to 48 hours.

Conclusions:

• The engineered Abdurin scaffold can yield high-affinity binders against cancer targets like EphA2.
• Abdurins possess favorable properties, including long serum half-life and specific tumor targeting.
• These findings support the potential of Abdurins as a therapeutic or diagnostic platform for EphA2-expressing cancers.