Send to

Choose Destination
See comment in PubMed Commons below



Leung K.


Molecular Imaging and Contrast Agent Database (MICAD) [Internet]. Bethesda (MD): National Center for Biotechnology Information (US); 2004-2013.
2011 Feb 05 [updated 2011 May 04].


The amphibian bombesin (BBN or BN, a peptide of 14 amino acids) is an analog of human gastrin-releasing peptide (GRP, a peptide of 27 amino acids) that binds to GRP receptor (GRPR) with high affinity and specificity (1). Both GRP and BBN share an amidated C-terminus sequence homology of seven amino acids, Trp-Ala-Val-Gly-His-Leu-Met-NH2. BBN-Like peptides have been shown to induce various biological responses in diverse tissues, including the central nervous system (CNS) and the gastrointestinal (GI) system. They also act as potential growth factors for both normal and neoplastic tissues (2). Specific BBN receptors have been identified on CNS and GI tissues, including the pancreas, and on a number of tumor cell lines. The BBN-receptor superfamily includes at least four different subtypes, namely neuromedin B (NMB or BB1), the GRPR subtype (BB2), the BB3 subtype, and the BB4 subtype (3). The findings of GRPR overexpression in various human tumors, such as breast, prostate, lung, colon, ovarian, and pancreatic cancers, provide opportunities for tumor imaging by designing specific molecular imaging agents to target the GRPR. Currently used targeting GRPR peptides are primarily agonists. Therefore, there is a need for GRPR antagonist radioligands. Llinares et al. (4) developed a series of GRPR peptide antagonists. One of them, d-Phe-Gln-Trp-Ala-Val-Gly-His-Sta-Leu-NH2 (RM26), has been found to be a selective GRPR antagonist. A DOTA-Gly-benzoyl group was added to the C-terminus to form DOTA-Gly-benzoyl-d-Phe-Gln-Trp-Ala-Val-Gly-His-Sta-Leu-NH2 (RM1). For evaluation as a single-photon emission computed tomography (SPECT) imaging agent for GRPR, 111In has been attached to RM1 to form 111In-RM1 (5). A new GRPR peptide antagonist, DOTA-4-amino-1-carboxymethyl-piperidine-d-Phe-Gln-Trp-Ala-Val-Gly-His-Sta-Leu-NH2 (RM2), has been found to have a higher affinity for GRPR than RM1 and has been labeled with 111In for single-photon emission computed tomography (SPECT) imaging (6).

PubMed Commons home

PubMed Commons

How to join PubMed Commons
    Support Center