title: 3'-99mTc-labeling and biodistribution of a CAPL antisense oligodeoxynucleotide.
abstract: CAPL is a cancer-related gene shown to be overexpressed during tumor metastasis formation. A CAPL antisense oligodeoxynucleotide (ODN), GX-1, and a random control ODN (CTRL1) were 3'-conjugated to MAG3, labeled with technetium-99m, purified, and the biodistribution of the radiolabeled conjugates in normal mice was studied. A 99mTc-MAG3-GX-1 complex of >97% radiochemical purity was obtained and the product was stable for >6 h as determined by reversed phase high performance liquid chromatography (HPLC). Biodistribution studies of the 99mTc-MAG3-ODNs in groups of four normal mice, sacrificed 5 min and 60 min after injection, demonstrated that the radiolabeled ODNs were distributed in an unspecific manner. The excretion route was mainly urinary. At 60 min, 55.2% of the injected dose of 99mTc-MAG3-GX-1 and 72.4% of 99mTc-MAG3-CTRL1 was found in the urine. This finding is clearly different from previously reported data on tritiated 20-mer phosphodiester ODNs, as well as the unconjugated 99mTc-MAG3 chelate, suggesting that 99mTc-MAG3 coupled to the 3'-end of ODNs has an influence on the biodistribution of the oligo, and possibly has a protective function to enzymatic degradation in vivo.
authors.affiliation: Department of Pharmaceutics, University of Oslo, Norway. ole.hjelstuen@isopharma.no
authors.forename: O K
authors.initials: OK
authors.lastname: Hjelstuen
authors.forename: H H
authors.initials: HH
authors.lastname: Tønnesen
authors.forename: P O
authors.initials: PO
authors.lastname: Bremer
authors.forename: A M
authors.initials: AM
authors.lastname: Verbruggen
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid; D007267:Injections; D051379:Mice; D016376:Oligonucleotides, Antisense / Q000008:administration & dosage / Q000138:chemical synthesis* / Q000494:pharmacology*; D019275:Radiopharmaceuticals / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism; D000071999:S100 Calcium-Binding Protein A4; D009418:S100 Proteins / Q000235:genetics*; D013670:Sodium Pertechnetate Tc 99m / Q000737:chemistry; D013667:Technetium / Q000737:chemistry*; D017263:Technetium Tc 99m Mertiatide / Q000737:chemistry; D014018:Tissue Distribution
chemical_list: D016376:Oligonucleotides, Antisense; D019275:Radiopharmaceuticals; D000071999:S100 Calcium-Binding Protein A4; D009418:S100 Proteins; C470944:S100a4 protein, mouse; D017263:Technetium Tc 99m Mertiatide; D013667:Technetium; D013670:Sodium Pertechnetate Tc 99m