Depreotide is a peptide analogue of a somatostatin receptor that preferentially binds to somatostatin receptors 2, 3, and 5. Many lung tumors may express these receptors to a greater extent than normal tissue. Depreotide study is a noninvasive, receptor-specific imaging agent that is used to assess malignant versus benign single pulmonary nodules before biopsy.
CAT No: 10-101-102
CAS No:161982-62-3
Synonyms/Alias:NeoTec; P 829; P829; D03687; P-829
Chemical Name:(2S)-6-amino-2-[[(2R)-2-[[(2S)-6-amino-2-[[(2S)-2-amino-3-[[2-[2-[(2S,5S,8S,11R,14S,17S)-14-(4-aminobutyl)-5-benzyl-8-[(4-hydroxyphenyl)methyl]-11-(1H-indol-3-ylmethyl)-4-methyl-3,6,9,12,15,18-hexaoxo-17-propan-2-yl-1,4,7,10,13,16-hexazacyclooctadec-2-yl]ethylsulfanyl]acetyl]amino]propanoyl]amino]hexanoyl]amino]-3-sulfanylpropanoyl]amino]hexanamide;technetium
Depreotide is a synthetic peptide compound designed to mimic somatostatin analogs, exhibiting high affinity for specific somatostatin receptor subtypes. As a cyclic peptide, it features a stable structure that enhances its receptor-binding properties, making it a valuable tool for probing peptide-receptor interactions. Its unique biochemical profile has positioned it as an important research reagent for studies involving receptor targeting, peptide-based imaging, and the elucidation of somatostatin-mediated signaling pathways. With applications spanning molecular pharmacology and peptide engineering, Depreotide is frequently utilized in laboratories investigating receptor-ligand dynamics and peptide functionality.
Receptor Binding Studies: Depreotide serves as a robust model compound for characterizing somatostatin receptor subtypes, particularly SSTR2 and SSTR5, in vitro. Researchers employ it to assess binding affinities, receptor selectivity, and competitive displacement of endogenous ligands. By enabling precise quantification of peptide-receptor interactions, it supports the development of structure-activity relationship (SAR) models and the mapping of critical binding domains within target receptors. Such studies are instrumental in advancing the understanding of G protein-coupled receptor (GPCR) biology and the nuances of peptide-mediated signaling.
Peptide-Based Imaging Research: The compound's strong receptor affinity and metabolic stability render it a preferred scaffold for the development of novel imaging agents. In preclinical settings, Depreotide is conjugated with various reporter groups or radiolabels to create targeted molecular probes. These conjugates facilitate the visualization of somatostatin receptor expression in cell-based assays, tissue sections, and animal models. The resulting imaging data provide insights into receptor distribution, density, and dynamics, which are crucial for validating new imaging strategies and evaluating receptor-targeted delivery systems.
Ligand-Receptor Interaction Assays: In high-throughput screening and pharmacological profiling, Depreotide is widely used as a reference ligand to benchmark the activity of experimental peptides and small molecules. Its well-characterized interaction with somatostatin receptors allows for reliable comparison of agonist and antagonist activities in functional assays. This application is particularly valuable for drug discovery programs focused on modulating neuroendocrine signaling pathways, as it enables accurate assessment of candidate compound efficacy and selectivity.
Peptide Structure-Function Analysis: The cyclic nature and defined sequence of Depreotide make it an exemplary model for investigating the relationship between peptide conformation and biological activity. Researchers utilize it to study how specific amino acid substitutions, cyclization strategies, and structural modifications influence receptor binding and downstream signaling. These insights inform the rational design of next-generation peptide therapeutics and imaging agents, as well as the optimization of peptide stability and bioavailability for research applications.
Peptide Synthesis and Analytical Method Development: Depreotide is also employed as a standard in the optimization and validation of peptide synthesis protocols and analytical techniques. Its defined sequence and stability make it suitable for calibrating chromatographic systems, mass spectrometry platforms, and peptide purification workflows. By serving as a reliable reference compound, it enables laboratories to ensure reproducibility, accuracy, and quality control in peptide production and analytical assessment, supporting a wide range of research and development activities in peptide science.
99mTc-depreotide uptake was found in 62 out of 66 malignancies, including 57 of 58 primary lung cancer cases. Two cases of lung metastasis (one from a colon cancer and one from an adenoid cystic carcinoma originating in the palate) and one rib chondrosarcoma did not show depreotide uptake. There were 33 patients with benign lesions, of whom 16 displayed false-positive 99mTc-depreotide uptake, whereof 11 were pneumonias. Tc-99m-depreotide uptake was absent in 17 patients with benign lesions, including all 10 hamartomas. The sensitivity in detecting malignancy was 94%, and in detecting lung cancer 98%. The specificity was calculated based on two sets of data. When all cases were used, the specificity was 52%. If the 12 pneumonias are excluded, the specificity was 77%.
Axelsson, R., Herlin, G., Bååth, M., Aspelin, P., & Kölbeck, K. G. (2008). Role of scintigraphy with technetium-99m depreotide in the diagnosis and management of patients with suspected lung cancer. Acta Radiologica, 49(3), 295-302.
Of 21 patients who had a focal high uptake of Depreotide, 17 were malignancies. One patient had two lesions with high Depreotide uptake, lung cancer, and pneumonia in the contralateral lung. Two patients with sarcoidosis and one with bilateral round atelectasis also had high Depreotide uptake bilaterally. Seven of the 8 patients with no uptake were true negative: 5 hamartomas and 2 round atelectases. One small lung cancer in the pleura sinus did not have Depreotide uptake.
Bååth, M., Kölbeck, K. G., & Danielsson, R. (2004). Somatostatin receptor scintigraphy with 99mTc-Depreotide (NeoSpect) in discriminating between malignant and benign lesions in the diagnosis of lung cancer: a pilot study. Acta Radiologica, 45(8), 833-839.
Tc-depreotide imaging has low sensitivity but is useful in a one-third of OctreoScan-negative patients, displaying significantly better uptake than In-pentetreotide in this patient group. It aids diagnosis by highlighting lesions not seen by OctreoScan and/or CT/MRI imaging, and can possibly identify a group of patients amenable to therapy with radionuclide agents, such as SOM230, targeting somatostatin receptor subtypes 2, 3 and 5.
Shah, T., Kulakiene, I., Quigley, A. M., Warbey, V. S., Srirajaskanthan, R., Toumpanakis, C., ... & Caplin, M. E. (2008). The role of 99mTc-depreotide in the management of neuroendocrine tumours. Nuclear medicine communications, 29(5), 436-440.
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