Preclinical evaluation of a humanized NR-LU-10 antibody-streptavidin fusion protein for pretargeted cancer therapy.

Abstract

A humanized single chain Fv antibody fragment specific to the EGP40 antigen was genetically engineered as a streptavidin fusion (scFvSA) for use in pretargeted radioimmunotherapy. The scFvSA construct was expressed as a soluble, tetrameric species in the Escherichia coli periplasm at 110-140 mg/liter. The fusion protein was purified from crude lysates by iminobiotin affinity chromatography with an overall yield of 50-60%. Characterization of the purified protein by SDS-PAGE, light scattering, and size exclusion chromatography demonstrated that the fusion protein was tetrameric with a molecular weight of approximately 172,000. Competitive immunoreactivity assays showed a two-fold greater binding to the antigen than the comparable whole antibody. The purified protein had a biotin disassociation rate identical to recombinant streptavidin and bound an average of three of four possible biotins per molecule. The radiolabeled fusion protein showed a faster blood clearance rate in normal mice than the corresponding whole antibody-streptavidin chemical conjugate. Tumor-specific targeting of a subsequently administered radionuclidechelate/biotin molecule was demonstrated in nude mice bearing SW1222 human colon carcinoma xenografts. A single dose of 800 microCi of 90Y-DOTA-biotin produced cures in mice with established subcutaneous human small cell lung or colon cancer xenografts.

• Authors: S Goshorn, J Sanderson, D Axworthy, Y Lin, M Hylarides, J Schultz
• Journal: Cancer biotherapy & radiopharmaceuticals (Cancer Biother Radiopharm) Vol. 16 Issue 2 Pg. 109-23 (Apr 2001) ISSN: 1084-9785 [Print] United States
• PMID: 11385958 (Publication Type: Journal Article)

Chemical References

• Antigens, Neoplasm
• CD3 Complex
• Cell Adhesion Molecules
• Epithelial Cell Adhesion Molecule
• Immunoglobulin Fragments
• Iodine Radioisotopes
• Recombinant Fusion Proteins
• immunoglobulin Fv
• Streptavidin

Topics

• Animals
• Antigens, Neoplasm (genetics, immunology)
• CD3 Complex (genetics, immunology)
• Cell Adhesion Molecules (genetics, immunology)
• Colonic Neoplasms (drug therapy, metabolism)
• Drug Evaluation, Preclinical
• Electrophoresis, Polyacrylamide Gel
• Epithelial Cell Adhesion Molecule
• Escherichia coli (genetics, metabolism)
• Female
• Genetic Vectors
• Humans
• Immunoglobulin Fragments (therapeutic use)
• Iodine Radioisotopes (administration & dosage)
• Mice
• Mice, Inbred BALB C
• Mice, Nude
• Radioimmunotherapy
• Recombinant Fusion Proteins (pharmacokinetics, therapeutic use)
• Streptavidin (genetics, immunology)
• Tissue Distribution
• Xenograft Model Antitumor Assays