Preclinical Evaluation of an Anti-EphA2 Minibody-Based ImmunoPET Agent as a Diagnostic Tool For Cancer
- 19.09.2025
- Research Article
- Verfasst von
- Peggy A. Birikorang
- H. E. G. Wedaarachchi
- Jordan A. Smith
- Gary Kohanbash
- W. Barry Edwards
- Erschienen in
- Molecular Imaging and Biology
Abstract
Purpose
In this study, we report the development and characterization of a copper-64 (64Cu) radiolabeled anti-EphA2 minibody (Mb) for pre-treatment characterization of antigen expression via Positron Emission Tomography (PET). Minibodies, ≈85 kDa molecular weight antibody fragments, are advantageous as targeting molecules due to accelerated serum clearance which enables imaging at earlier time points relative to the parent IgG. As EphA2, a tyrosine kinase receptor, is overexpressed in various cancer types with minimal expression in normal tissue, rapid quantification of EphA2 expression could be beneficial for patient stratification.
Procedures.
Recombinantly produced anti-EphA2-Mb was evaluated for purity, stability, affinity, and in vivo target localization. Following bifunctional chelator conjugation, radiolabeling with 64Cu and evaluating purity, stability and immunoreactivity of resultant radioimmunoconjugate, [64Cu]Cu-NOTA-anti-EphA2-Mb, 11.1 MBq (300 μCi) and 0.2 MBq (5 μCi) doses were administered to HT1080-fibrosarcoma-bearing nude mice for in-vivo PET imaging and ex-vivo biodistribution analyses respectively at 4 and 24 h post-injection (p.i.). Antigen-specificity was assessed via a blocked control group which received the dose co-administered with non-radiolabeled anti-EphA2-Mb.
Results
Anti-EphA2-Mb produced via recombinant protein expression was pure, stable and had high binding affinity to human EphA2 antigen (KD = 0.63 ± 0.24 nM). When labeled with 64Cu via NOTA, [64Cu]Cu-NOTA-anti-EphA2-Mb had high purity, in-vitro stability in PBS and mouse serum up to 24 h, and high immunoreactivity. On administering to tumor-bearing mice, [64Cu]Cu-NOTA-anti-EphA2-Mb exhibited rapid tumor targeting with 25.53±2.92%ID/g at 4 h, and 22.13±7.68%ID/g at 24 h p.i. Competitive inhibition reduced tumor uptake (11.24±0.88%D/g, 24 h p.i., p = 0.0286). There was minimal uptake of the radiotracer in non-target tissues, except kidney and liver, and fast clearance from the blood, with high tumor to blood ratios. Tumor SUVmean values obtained from region of interest (ROI) Quantification of the PET images were 1.13±0.03 and 1.08±0.06 at 4 and 24 h respectively.
Conclusion
Our findings demonstrate that anti-EphA2-Mb is an excellent targeting molecule, and [64Cu]Cu-NOTA-anti-EphA2-Mb is a promising immunoPET agent with potential for use for other theranostic applications.
Anzeige
- Titel
- Preclinical Evaluation of an Anti-EphA2 Minibody-Based ImmunoPET Agent as a Diagnostic Tool For Cancer
- Verfasst von
-
Peggy A. Birikorang
H. E. G. Wedaarachchi
Jordan A. Smith
Gary Kohanbash
W. Barry Edwards
- Publikationsdatum
- 19.09.2025
- Verlag
- Springer International Publishing
- Erschienen in
-
Molecular Imaging and Biology
Print ISSN: 1536-1632
Elektronische ISSN: 1860-2002 - DOI
- https://doi.org/10.1007/s11307-025-02048-7
Dieser Inhalt ist nur sichtbar, wenn du eingeloggt bist und die entsprechende Berechtigung hast.
Dieser Inhalt ist nur sichtbar, wenn du eingeloggt bist und die entsprechende Berechtigung hast.
