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Peptide Receptor Radionuclide Therapy for Neuroendocrine Tumours
Published in Michael Ljungberg, Handbook of Nuclear Medicine and Molecular Imaging for Physicists, 2022
Anna Sundlöv, Katarina Sjögreen Gleisner
The somatostatin receptor (SSTR) is a transmembrane, G-protein-coupled receptor that is expressed by neuroendocrine cells present in most tissues and organs throughout the body. NETs, being tumours made up of neuroendocrine cells, have an especially high receptor density. There are five subtypes of the SSTR, and different tissues express different combinations of receptor subtypes. The natural ligand, somatostatin, is a hormone secreted by the hypothalamus, whose function is to inhibit the hormonal secretion from neuroendocrine cells [2]. The same effect can be achieved through injection of a synthetic analogue of somatostatin (SSA), which has been used since the 1980s to treat acromegaly (hypersecretion of growth hormone) and NETs.
Electroactive Polymers for Drug Delivery
Published in Inamuddin, Mohd Imran Ahamed, Rajender Boddula, Adil A. Gobouri, Electroactive Polymeric Materials, 2022
Mehdi Mogharabi-Manzari, Masoud Salehipour, Zahra Pakdin-Parizi, Shahla Rezaei, Roya Khosrokhavar, Ali Motaharian
Silva et al. (2018) reported polyaniline decorated by zif-8 nanoparticles was an efficient chemo and photothermal smart carrier for the delivery of 5-fluorouracil. Somatostatin receptors are overexpressed in some tumors and lanreotide (a synthetic analog of somatostatin) is used as a medication for the treatment of neuroendocrine tumors. Nguyen et al. (2018) designed a nanostructured hybrid polymer for the targeted delivery of chemotherapy drugs to cancer cells by conjugating polyaniline with lanreotide that presented a high tendency for binding to somatostatin receptors.
Arsenals of Pharmacotherapeutically Active Proteins and Peptides: Old Wine in a New Bottle
Published in Debarshi Kar Mahapatra, Swati Gokul Talele, Tatiana G. Volova, A. K. Haghi, Biologically Active Natural Products, 2020
The excessive synthesis of ST results in a condition called acromegaly. The major reasons behind the excessive synthesis of ST are somatotroph adenomas of the pituitary gland. The acromegaly can be treated by removing the adenomas surgically followed by radiation therapy and administering drugs. Somatostatin analogs like octreotide are used for the inhibition of growth hormone synthesis. These analogs also inhibit the secretion of insulin, glucagon, and several GI hormones and trigger cholelithiasis. Pegvisomant is a recombinant hGH analog which has an ST receptor antagonist [134].
Theranostic approaches in nuclear medicine: current status and future prospects
Published in Expert Review of Medical Devices, 2020
Luca Filippi, Agostino Chiaravalloti, Orazio Schillaci, Roberto Cianni, Oreste Bagni
NET are characterized by the overexpression of receptors for the endogenous peptide somatostatin, which exerts a pleitropic inhibiting effect on hormone releasing, gastrointestinal motility, and cellular growth [39]. Five subtypes of somatostin receptors (SSTRs 1–5) have been identified and belong to a distinct group within the superfamily of G-protein-coupled receptors with seven transmembrane domains. NET present high density of SSTRs 2, so the synthetic long-acting analogs octreotide and lanreotide were approved and extensively applied for the treatment of NET.
Nuclear Medicine in Oncology
Published in Computer Methods in Biomechanics and Biomedical Engineering: Imaging & Visualization, 2018
Carla Oliveira, Rui Parafita, Ana Canudo, Joana Correia Castanheira, Durval C. Costa
The main candidates for this therapy are the neuroendocrine tumours of a gastroenteropancreatic origin (typically those that are well differentiated). Apart from well or moderately differentiated gastroenteropancreatic neuroendocrine tumours (NET), other NET with an increased expression of somatostatin receptors may benefit from a treatment with radiolabelled peptides (such as NET of bronchial origin, tumours of the sympathetic-adrenal axis or medullary thyroid carcinoma).