The alpha(v)beta(3) integrin is expressed on proliferating endothelial cells such as those present in growing tumors, as well as on tumor cells of various origin. Tumor-induced angiogenesis can be blocked in vivo by antagonizing the alpha(v)beta(3) integrin with small peptides containing the Arg-Gly-Asp (RGD) amino acid sequence. This tripeptidic sequence, naturally present in extracellular mat...

UNLABELLED Peptides are useful tools for the targeted delivery of radionuclides or chemotherapeutic drugs to their site of action within an organism. Given that the peptide receptor is overexpressed at the tumor, therapeutically active doses can be delivered to the tumor with reduced side effects. Because currently known peptides are restricted to a small number of tumors, new molecules and the...

In patients with progressive metastatic (or recurrent) differentiated thyroid carcinoma that either do not take up radioiodine or are unresponsive to continued radioiodine therapy, staging is difficult and treatment options are few. However, in most of these patients uptake of radiolabeled somatostatin analogs is evident on somatostatin-receptor scintigraphy (SRS). Using SRS, patients with suff...

BACKGROUND Polybasic helical peptides, such as peptide p5, bind human amyloid extracts and synthetic amyloid fibrils. When radiolabeled, peptide p5 has been shown to specifically bind amyloid in vivo thereby allowing imaging of the disease. Structural requirements for heparin and amyloid binding have been studied using analogs of p5 that modify helicity and chirality. METHODS Peptide-ligand i...

UNLABELLED Activatable cell-penetrating peptides (ACPPs) are a new class of promising molecular imaging probes for the visualization of enzymes in vivo. The cell-penetrating function of a polycationic peptide is efficiently blocked by intramolecular electrostatic interactions with a polyanionic peptide. Proteolysis of a cleavable linker present between the polycationic cell-penetrating peptide ...

Radiolabeled cyclic RGD peptides targeting integrin αvβ3 are reported as promising agents for the early diagnosis of metastatic tumors. With an aim to improve tumor uptake and retention of the peptide, cyclic RGD peptide dimer E[c (RGDfK)] 2 (E = Glutamic acid, f = phenyl alanine, K = lysine) coupled to the bifunctional chelator DOTA was custom synthesized and radiolabelled with Ga. Radiolabell...

Angiogenesis plays a key role in cancer progression and correlates with disease aggressiveness and poor clinical outcomes. Affinity ligands discovered by screening phage display random peptide libraries can be engineered to molecularly target tumor blood vessels for noninvasive imaging and early detection of tumor aggressiveness. In this study, we tested the ability of a phage-display-selected ...

Cancer-specific targeting sparing normal tissues would significantly enhance cancer therapy outcomes and reduce cancer-related mortality. One approach is to target receptors or molecules that are specifically expressed on cancer cells. Peptides as cancer-specific targeting agents offer advantages such as ease of synthesis, low antigenicity, and enhanced diffusion into tissues. Glucose-regulated...