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Gallium-68 Complex of a Macrobicyclic Cage Amine Chelator Tethered to Two Integrin-Targeting Peptides for Diagnostic Tumor Imaging

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dc.contributor.authorMa, M.
dc.contributor.authorNeels, O.
dc.contributor.authorDenoyer, D.
dc.contributor.authorRoselt, P.
dc.contributor.authorKaras, J.
dc.contributor.authorScanlon, D.
dc.contributor.authorWhite, J.
dc.contributor.authorHicks, R.
dc.contributor.authorDonnelly, P.
dc.contributor.schoolSchool of Chemistry and Physics
dc.date.issued2011
dc.description.abstractTumor-targeting peptides radiolabeled with positron-emitting (68)Ga are promising candidates as new noninvasive diagnostic agents for positron emission tomography (PET). The targeting peptides are tethered to a chelator that forms a stable coordination complex with Ga(3+) that is inert to dissociation of Ga(3+)in vivo. Metal complexes of macrobicyclic hexaamine "sarcophagine" (sar = 3,6,10,13,16,19-hexaazabicyclo[6.6.6]icosane) ligands exhibit remarkable stability as a result of the encapsulating nature of the cage amine ligand. A Ga(3+) sarcophagine complex, [Ga-(1-NH(3)-8-NH(2)-sar)](4+), has been characterized using X-ray crystallography, demonstrating that Ga(3+) is coordinated to six nitrogen atoms in a distorted octahedral complex. A bifunctional derivative of (NH(2))(2)sar, possessing two aliphatic linkers with carboxylic acid functional groups has been attached to two cyclic-RGD peptides that target the α(v)β(3) integrin receptor that is overexpressed in some types of tumor tissue. This dimeric species can be radiolabeled with (68)Ga(3+) in >98% radiochemical yield and (68)Ga(3+) does not dissociate from the ligand in the presence of transferrin, an endogenous protein with high affinity for Ga(3+). Biodistribution and micro-PET imaging studies in tumor-bearing mice indicate that the tracer accumulates specifically in tumors with high integrin expression. The high tumor uptake is coupled with low nonspecific uptake and clearance predominantly through the kidneys resulting in high-quality PET images in animal models.
dc.description.statementofresponsibilityMichelle T. Ma, Oliver C. Neels, Delphine Denoyer, Peter Roselt, John A. Karas, Denis B. Scanlon, Jonathan M. White, Rodney J. Hicks, and Paul S. Donnelly
dc.identifier.citationBioconjugate Chemistry, 2011; 22(10):2093-2103
dc.identifier.doi10.1021/bc200319q
dc.identifier.issn1043-1802
dc.identifier.issn1520-4812
dc.identifier.urihttp://hdl.handle.net/2440/71354
dc.language.isoen
dc.publisherAmer Chemical Soc
dc.relation.grantARC
dc.relation.grantNHMRC
dc.rights© 2011 American Chemical Society
dc.source.urihttps://doi.org/10.1021/bc200319q
dc.subjectCell Line, Tumor
dc.subjectAnimals
dc.subjectMice, Inbred BALB C
dc.subjectHumans
dc.subjectMice
dc.subjectNeoplasms
dc.subjectGallium Radioisotopes
dc.subjectPeptides, Cyclic
dc.subjectDipeptides
dc.subjectIntegrin alphaVbeta3
dc.subjectRadiopharmaceuticals
dc.subjectPositron-Emission Tomography
dc.titleGallium-68 Complex of a Macrobicyclic Cage Amine Chelator Tethered to Two Integrin-Targeting Peptides for Diagnostic Tumor Imaging
dc.typeJournal article
pubs.publication-statusPublished

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