Synthesis and Characterization of 111In-DTPA-N-TIMP-2: A Radiopharmaceutical for Imaging Matrix Metalloproteinase Expression

Giersing, B.K. and Rae, M.T. and CarballidoBrea, M. and Williamson, R.A. and Blower, P.J. (2001) Synthesis and Characterization of 111In-DTPA-N-TIMP-2: A Radiopharmaceutical for Imaging Matrix Metalloproteinase Expression. Bioconjug Chemistry, 12 (6). pp. 964-971. ISSN 1043-1802 . (The full text of this publication is not available from this repository)

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Official URL
http://dx.doi.org/10.1021%2Fbc010028f

Abstract

The matrix metalloproteinases (MMPs) are enzymes involved in the turnover of the extracellular matrix. Their overexpression in tumors is implicated in the metastatic process and may provide a target for diagnostic tumor imaging by using a radiolabeled inhibitor. MMPs are inhibited by endogenous tissue inhibitors of metalloproteinases (TIMPs). Thus, TIMPs are potential targeting molecules which could be used as vehicles for selective radionuclide delivery by virtue of their binding to MMPs. The aim of this work was to produce a radiopharmaceutical with which to evaluate this potential. The 127 amino acid N-terminal domain of recombinant human TIMP-2 (N-TIMP-2) was conjugated with the bifunctional chelator diethylenetriamine pentaacetic acid (DTPA). Singly modified DTPA-N-TIMP-2 conjugate (identified by electrospray ionization mass spectrometry) was isolated by anion-exchange chromatography. The primary site of DTPA modification on N-TIMP-2 was mapped to lysine-116, which is distant from the site of MMP interaction. The conjugate was radiolabeled with indium-111 to give 111In-DTPA-N-TIMP-2 with a specific activity of at least 4 MBq/microg and a radiochemical yield and purity of >95%, by incubation with 111InCl3, without need for postlabeling purification. The product was sterile, pyrogen-free, and stable in serum over 48 h and retained full inhibitory activity in a fluorimetric binding assay. With these attributes, 111In-DTPA-N-TIMP-2 is a suitable radiopharmaceutical for in vivo biological and clinical investigation of the potential benefits of imaging MMP expression.

Item Type: Article
Uncontrolled keywords: Humans Indium Radioisotopes/*diagnostic use Matrix Metalloproteinases/*analysis/metabolism Neoplasm Proteins/analysis/metabolism Pentetic Acid/*chemistry Peptide Mapping Protein Binding Radiopharmaceuticals/*chemical synthesis/metabolism Tissue Inhibitor of Metalloproteinase-2/*chemistry
Subjects: Q Science
Divisions: Faculties > Science Technology and Medical Studies > School of Biosciences > Protein Science Group
Depositing User: Richard Williamson
Date Deposited: 30 Sep 2008 18:23
Last Modified: 14 Jan 2010 14:20
Resource URI: http://kar.kent.ac.uk/id/eprint/5305 (The current URI for this page, for reference purposes)
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