In vitro and in vivo characterization of three 68Ga- and 111In-labeled peptides for cholecystokinin receptor imaging.

Cholecystokinin (CCK) receptors are overexpressed in several human tumor types, such as medullary thyroid carcinomas and small cell lung cancers. Several ligands for the CCK2 receptor (CCK2R) have been developed for radionuclide targeting of these tumors. In this study, we evaluated whether radiolabeled DOTA-sCCK8 and its stabilized derivative, DOTA-sCCK8[Phe(2)(p-CH2SO3H), Nle(3,6)], are suitable for imaging of CCK2R-positive tumors, using DOTA-MG0 as a reference.

Comparative biodistribution of 12 ¹¹¹In-labelled gastrin/CCK2 receptor-targeting peptides.

Purpose: Cholecystokinin 2 (CCK-2) receptor overexpression has been demonstrated in various tumours such as medullary thyroid carcinomas and small-cell lung cancers. Due to this high expression, CCK-2 receptors might be suitable targets for radionuclide imaging and/or radionuclide therapy. Several CCK-2 receptor-binding radiopeptides have been developed and some have been tested in patients.

Stabilized (111)in-labeled sCCK8 analogues for targeting CCK2-receptor positive tumors: synthesis and evaluation.

Radiolabeled cholecystokinin-8 (CCK8) peptide analogues can be used for peptide receptor radionuclide imaging and therapy for tumors expressing CCK2/gastrin receptors. Earlier findings indicated that sulfated CCK8 (sCCK8, Asp-Tyr(OSO(3)H)-Met-Gly-Trp-Met-Asp-Phe-NH(2)) may have better characteristics for peptide receptor radionuclide therapy (PRRT) than gastrin analogues. However, sCCK8 contains an easily hydrolyzable sulfated tyrosine residue and two methionine residues which are prone to oxidation.

Radiolabeled CCK/gastrin peptides for imaging and therapy of CCK2 receptor-expressing tumors.

Cholecystokinin (CCK) receptors are overexpressed in numerous human cancers, like medullary thyroid carcinomas, small cell lung cancers and stromal ovarian cancers. The specific receptor-binding property of the endogenous ligands for these receptors can be exploited by labeling peptides with a radionuclide and using these as carriers to guide the radioactivity to the tissues that express the receptors. In this way, tumors can be visualized using positron emission tomography and single photon emission computed tomography imaging.

Targeting of a CCK(2) receptor splice variant with (111)In-labelled cholecystokinin-8 (CCK8) and (111)In-labelled minigastrin.

Purpose: Radiolabelled cholecystokinin (CCK) and gastrin-derived peptides potentially can be used for peptide receptor radionuclide therapy (PRRT). Recently, a splice variant version of the CCK2R has been identified, designated CCK2i4svR. Constitutive expression of this receptor has been demonstrated in human colorectal cancer and in pancreatic cancer, but not in normal tissue.