Samarium-153 and technetium-99m-labeled monoclonal antibodies in angiogenesis for tumor visualization and inhibition.

BACKGROUND

Angiogenesis is the development of new blood vessels from pre-existing ones. Vascular endothelial growth factor (VEGF) is one of the most important angiogenic activators. Our studies are focused on the detection of VEGF by use of radiolabeled anti-endothelial monoclonal antibodies, which have the ability to localize in newly-formed vasculature of a cancerous origin.

MATERIALS AND METHODS

The anti-endothelial monoclonal antibody VG76e was labeled with Samarium-153 and Technetium-99m. Biodistribution of the radiolabeled species was assessed in normal female Swiss mice, while tumor uptake was also evaluated.

RESULTS

VG76e was labeled with 99mTc and 153Sm, resulting in a single product with a labeling yield of over 95%. Biodistribution studies showed non-specific uptake in any organ, with elimination via the hepatobiliary system. Finally, satisfactory tumor uptake was observed for both radiolabeled derivatives.

CONCLUSION

Monoclonal antibodies raised against epithelial growth factors or their receptors, when labeled with appropriate radionuclides, may be a useful tool for early tumor detection and eventually for therapy.