Somatostatin receptor-binding peptides suitable for tumor radiotherapy with Re-188 or Re-186. Chemistry and initial biological studies.

Somatostatin derivative peptides previously designed for radiodiagnostic purposes (99mTc P829 or 99mTc depreotide) were reoptimized for radiotherapy of tumors with rhenium radioisotopes. An optimized pharmacophore peptide P1839 was derived by in vitro binding affinity assay to AR42J rat pancreatic tumor cell membranes. Peptides with chelating domains and their oxorhenium(V) complexes were tested in vitro for binding to NCI H69 human SCLC tumor membranes.

Localization of (99m)Tc-Labeled ApoB Synthetic Peptide in Arterial Lesions of an Experimental Model of Spontaneous Atherosclerosis.

We have previously shown that after administration of (123)I-SP-4 (a synthetic ApoB peptide fragment) to Watanabe heritable hyperlipidemic (WHHL) rabbits that foci of tracer uptake can be identified by external gamma camera imaging which correspond to regions of the aortas found to contain abundant atherosclerotic lesions at postmortem evaluation. Because (99m)Tc is preferred over (123)I for scintigraphic imaging, we prepared a (99m)Tc-labeled form of the SP-4 peptide, designated (99m)Tc-P199. To assess the feasibility of detecting atherosclerotic lesions using (99m)Tc-P199 and to compare the relative uptake of the (99m)Tc-labeled and radioiodinated peptides by such lesions, an admixture of (99m)Tc-199 and (125)I-SP-4 was administered to 11 WHHL and 2 normal rabbits.