Radiolabeled somatostatin analogs in prostate cancer

Thakur, Mathew L.; Kolan, H. R.; Li, J.; Wiaderkiewicz, Ryszard; Pallela, Venkat R.; Duggaraju, R.; Schally, Andrew V.

doi:10.1016/s0969-8051(96)00180-1

Cited by 44 publications

(18 citation statements)

References 26 publications

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“…In 8 of 31 biopsied patients with metastatic hormone-refractory PC, SST receptors were expressed both in vitro and in vivo, and visualized with the octreoscan technique [56]. SST analog RC-160 labeled with 99m Tc was shown to have a 400% higher 24-hour tumor uptake compared with 111 In-DTPA-octreotide due to specific tumor binding sites in nude mice bearing experimental human PCs [61]. In contrast, 111 In-DTPA-D-Phe1-octreotide scintigraphy identified only 3 of 7 patients with hormoneresistant PC who had the highest tumor to background ratio and responded to octreotide therapy [62].…”

Section: Presence Of Sstr In Pc Cellsmentioning

confidence: 99%

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Octreotide in the Management of Hormone-Refractory Prostate Cancer

Vainas

2001

Chemotherapy

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Patients with advanced or metastatic prostate cancer (PC), a partially hormone-resistant disease, will require some form of hormonal manipulations or some new therapeutic modalities. Octreotide, as somatostatin (SST) analogs, has been found to inhibit the growth of experimental PCs via several mechanisms, as indirect antihormonal and direct antimitogenic actions, mainly due to inhibition of SST receptor subtypes (SSTR-1–5). Sporadic clinical trials with octreotide (alone or with a complete antiandrogen blockade) treatment of patients with advanced stage D2 PC demonstrated promising results. Unfortunately, at present these clinical trials have some disadvantages and leave some uncertainty with regard to the trial design, the SSTR subtype determination and tumor localization with SSTR scintigraphy before the start of a selective SST analog, and finally the randomization in groups according to hormone resistance, dosage regimen and route of administration.

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Section: Presence Of Sstr In Pc Cellsmentioning

confidence: 99%

“…Fourth, somatostatin and its analogs inhibit ( fig. 3) the production of oncogene products or the overexpression of protooncogenes, which act in the tyrosine kinase stimulatory pathway [61]. Oncogene products are similar to GFs or are aberrant GF receptors, which promote tumor cell growth.…”

Section: Mechanisms Of Antiproliferative Actions Of Sst-14 and Sst Anmentioning

confidence: 99%

Octreotide in the Management of Hormone-Refractory Prostate Cancer

Vainas

2001

Chemotherapy

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“…Several somatostatin analogs have emerged carrying a variety of chelators utilized for efficient Tc labeling of biomolecules including small peptides [25][26][27][28], among them propylene amine oxime [29], open chain or cyclic tetraamines [30,31].…”

Section: Chelators For 99m Tc Labeling Of Somatostatin Analogsmentioning

confidence: 99%

Radiopharmaceuticals for somatostatin receptor imaging

Mikołajczak

Maecke

2016

Nucl. Med. Rev.

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“…Finally, the [O=Tc=O] + core, which forms octahedral Tc complexes with linear or macrocyclic tetraamines such as bifunctional cyclam-14 [27] and bifunctional 1,4,8,11-tetraazaundecane, [28][29][30][31] has been coupled to bioactive peptides as well as to biotin. [32] The monocationic unit [Tc(V)O 2 ](tetraamine) + shows high kinetic stability and confers high hydrophilicity to the peptides studied so far.…”

Section: Introductionmentioning

confidence: 99%

Tetraamine‐Derived Bifunctional Chelators for Technetium‐99m Labelling: Synthesis, Bioconjugation and Evaluation as Targeted SPECT Imaging Probes for GRP‐Receptor‐Positive Tumours

Abiraj¹,

Mansi²,

Tamma³

et al. 2010

Chemistry A European J

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Owing to its optimal nuclear properties, ready availability, low cost and favourable dosimetry, (99m)Tc continues to be the ideal radioisotope for medical-imaging applications. Bifunctional chelators based on a tetraamine framework exhibit facile complexation with Tc(V)O(2) to form monocationic species with high in vivo stability and significant hydrophilicity, which leads to favourable pharmacokinetics. The synthesis of a series of 1,4,8,11-tetraazaundecane derivatives (01-06) containing different functional groups at the 6-position for the conjugation of biomolecules and subsequent labelling with (99m)Tc is described herein. The chelator 01 was used as a starting material for the facile synthesis of chelators functionalised with OH (02), N(3) (04) and O-succinyl ester (05) groups. A straightforward and easy synthesis of carboxyl-functionalised tetraamine-based chelator 06 was achieved by using inexpensive and commercially available starting materials. Conjugation of 06 to a potent bombesin-antagonist peptide and subsequent labelling with (99m)Tc afforded the radiotracer (99m)Tc-N4-BB-ANT, with radiolabelling yields of >97% at a specific activity of 37 GBq micromol(-1). An IC(50) value of (3.7+/-1.3) nM was obtained, which confirmed the high affinity of the conjugate to the gastrin-releasing-peptide receptor (GRPr). Immunofluorescence and calcium mobilisation assays confirmed the strong antagonist properties of the conjugate. In vivo pharmacokinetic studies of (99m)Tc-N4-BB-ANT showed high and specific uptake in PC3 xenografts and in other GRPr-positive organs. The tumour uptake was (22.5+/-2.6)% injected activity per gram (% IA g(-1)) at 1 h post injection (p.i.). and increased to (29.9+/-4.0)% IA g(-1) at 4 h p.i. The SPECT/computed tomography (CT) images showed high tumour uptake, clear background and negligible radioactivity in the abdomen. The promising preclinical results of (99m)Tc-N4-BB-ANT warrant its potential candidature for clinical translation.

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Radiolabeled somatostatin analogs in prostate cancer

Cited by 44 publications

References 26 publications

Octreotide in the Management of Hormone-Refractory Prostate Cancer

Octreotide in the Management of Hormone-Refractory Prostate Cancer

Radiopharmaceuticals for somatostatin receptor imaging

Tetraamine‐Derived Bifunctional Chelators for Technetium‐99m Labelling: Synthesis, Bioconjugation and Evaluation as Targeted SPECT Imaging Probes for GRP‐Receptor‐Positive Tumours

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