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99m Tc-Diamine dioxime-Lys-Cys-Arg-Gly-Asp-Cyc-Phe-Cys-polyethylene glycol

Kam Leung

PMID: 20642000

Abstract:

Integrins are a family of heterodimeric glycoproteins on cell surfaces that mediate diverse biological events involving cell-cell and cell-matrix interactions (1). Integrins consist of an α and a β subunit and are important for cell adhesion and signal transduction. The αvβ3 integrin is the most prominent receptor affecting tumor growth, tumor invasiveness, metastasis, tumor-induced angiogenesis, inflammation, osteoporosis, and rheumatoid arthritis (2-7). Expression of the αvβ3 integrin is on tumor cells and activated endothelial cells, whereas expression is weak on resting endothelial cells and most normal tissues (6, 8, 9). The peptide sequence Arg-Gly-Asp (RGD) has been identified as a recognition motif used by extracellular matrix proteins (vitronectin, fibrinogen, laminin, and collagen) to bind to a variety of integrins, including αvβ3. Various radiolabeled antagonists have been introduced for imaging of tumors and tumor angiogenesis (10).
Most cyclic RGD peptides are composed of five amino acids. Various cyclic RGD peptides exhibit selective inhibition of binding to αvβ3 integrin (50% inhibition concentration (IC50), 7-40 nM) but no inhibition of binding to αvβ5 (IC50, 600-4,000 nM) or αIIbβ3 (IC50, 700-5,000 nM) integrins (11). Various radiolabeled cyclic RGD peptides and peptidominetics have been found to have high accumulation in tumors in mice (12, 13). Of these developments, [18F]galacto-c(RGDfK) has been evaluated in a number of clinical studies for imaging of αvβ3 integrin in cancer patients (14-19). Both αvβ3 and αvβ5 integrins bind to vitronectin (20). However, while the αvβ3 integrin is required for basic fibroblast growth factor-mediated angiogenesis, the αvβ5 integrin is required for vascular endothelial growth factor-induced angiogenesis (21, 22). The peptide Lys-Cys-Arg-Gly-Asp-Cyc-Phe-Cys (NC100717) was identified with phage display screening to be a potent and selective binder to both αvβ3 and αvβ5 integrins (23). A new peptide, NC100692, was derived from NC100717 with addition of diamine dioxime to the ε-amine of Lys and the N-terminal end modified with a short polyethylene glycol unit. Hua et al. (24) reported the development of 99mTc-NC100692 for single-photon emission computed tomography (SPECT) imaging of αvβ3 and αvβ5 integrins in mice with hindlimb ischemia. Bach-Gansmo et al. (25) has performed a preliminary study in patients with breast cancer.

Chemicals Related in the Paper:

Catalog Number Product Name Structure CAS Number Price
AP31961021-B O-Methyl-O′-succinylpolyethylene glycol 5′000 O-Methyl-O′-succinylpolyethylene glycol 5′000 31961-02-1 Price
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