title: Synthesis, radiolabeling and in vitro and in vivo characterization of a technetium-99m-labeled alpha-M2 peptide as a tumor imaging agent.
abstract: In an effort to develop a peptide-based radiopharmaceutical for the detection of breast cancer, we have prepared an analog of alphaM2 peptide, modified to incorporate an N3S chelate system. Mercaptoacetyltriglycine (MAG)(3)-derivatized alphaM2 peptide was prepared by solid-phase synthesis and radiolabeled with (99m)Tc by an exchange method. In vitro cell-binding on human breast cancer cell lines, MDA-MB-231 and MCF-7, indicated the affinity and specificity of (99m)Tc-MAG(3)-alphaM2 toward breast cancer cells. Additionally, the radiolabeled peptide showed rapid internalization into human breast cancer cells. In vivo biodistribution in mice showed that the radiolabeled peptide cleared rapidly from the blood and most non-target tissues and was excreted significantly via the kidneys. Uptake of (99m)Tc-MAG(3)-alphaM2 in the tumor was moderate. The radiochemical and in vitro and in vivo characterization indicates that the radiolabeled peptide has certain favorable properties and it might be a useful radiopharmaceutical for the detection of breast cancer in vivo.
authors.affiliation: Cyclotron and Radiopharmaceuticals Department, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia. sokarvi@kfshrc.edu.sa
authors.forename: S M
authors.initials: SM
authors.lastname: Okarvi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism; D045744:Cell Line, Tumor; D005260:Female; D006801:Humans; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D015609:Organotechnetium Compounds / Q000138:chemical synthesis* / Q000493:pharmacokinetics*; D010455:Peptides / Q000138:chemical synthesis* / Q000378:metabolism / Q000493:pharmacokinetics*; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000138:chemical synthesis* / Q000737:chemistry / Q000493:pharmacokinetics*; D013667:Technetium / Q000737:chemistry / Q000378:metabolism
chemical_list: D015609:Organotechnetium Compounds; D010455:Peptides; D019275:Radiopharmaceuticals; C495943:technetium-99m-labeled alpha-M2 peptide; D013667:Technetium