Iodine-131 labelled octreotide: not an option for somatostatin receptor therapy

Bakker, Willem H.; Breeman, W. A. P.; Pluijm, Marcel E. van der; Jong, Marion de; Visser, Theo J.; Krenning, Eric P.

doi:10.1007/bf00843706

Cited by 23 publications

(15 citation statements)

References 20 publications

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“…188 Re-RC-160 also underwent radiolysis which was clearly evident by TLC analysis even 2.5 hours post-preparation. Recently, 131 I-octreotide was reported to exhibit a similar lack of stability [12] as observed in our studies, however, no stabilizers were evaluated.…”

Section: Stability Studiessupporting

confidence: 40%

Ascorbic Acid Stabilization of Re-188- and I-131-Radiolabeled Peptides for Radiotherapy

Guhlke¹,

Zamora²,

Sartor³

et al. 1997

Radiochimica Acta

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Re-188 labeled RC-160 [cyclic NH 2 -(D)-Phe-Cys-iyr-(D)-TrpLys-Val-Cys-Trp-NH 2 ] cyclic NH is a radiolabeled somatostatin analog which is being explored for its potential as a local/regionally administered radiotherapeutic agent targeting somatostatin-receptor-positive tumors. The stability of I88 Re-RC-160 towards radiolytic effects is a prerequisite for the success of such an approach. High radiation flux was found to result in radiolysis of the peptide, but addition of ascorbic acid to preparations of RC-160 and also somatostatin-14 was found to stabilize these peptides minimizing these radiolytic effects. Subsequent to ascorbic acid stabilization, ,88 Re-RC-160 was determined in vitro and in vivo to bind to somatostatin-receptor-positive cells (NCI-H69 human small cell lung carcinoma) but not to receptor-negative cells (Raji, Burkitt's lymphoma). The comparative binding of Re-188 labeled RC-160 or CTOP [cyclic NH 2 -(D)-PheCysTyr-(D)-Trp-Om-Thr-Pen-Thr-ol], a μ-opiod-receptor antagonist used as a negative control compound, was also determined in vitro and in vivo using NCI-H69 cells as targets. 188 Re-RC-160 demonstrated a higher amount of net binding in vitro and in vivo compared to ,88 ReCTOP.

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Section: Stability Studiessupporting

confidence: 40%

Ascorbic Acid Stabilization of Re-188- and I-131-Radiolabeled Peptides for Radiotherapy

Guhlke¹,

Zamora²,

Sartor³

et al. 1997

Radiochimica Acta

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“…Although one of the most important therapeutic radioisotopes used for several decades, the use of 131 octreotide for SSTR-targeted therapy, 28 possibly attributable to its radionuclidic decay properties. Yttrium-90 and 177 Lu are the most successfully used b -emitting radionuclides, whereas the Auger electron-emitting radionuclide, 111 In, is also explored, although with relatively less success for PRRT.…”

Section: Radionuclide Selectionmentioning

confidence: 99%

Peptide Receptor Radionuclide Therapy: An Overview

Dash

Chakraborty

Pillai³

et al. 2015

Cancer Biotherapy and Radiopharmaceuticals

102

101

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Peptide receptor radionuclide therapy (PRRT) is a site-directed targeted therapeutic strategy that specifically uses radiolabeled peptides as biological targeting vectors designed to deliver cytotoxic levels of radiation dose to cancer cells, which overexpress specific receptors. Interest in PRRT has steadily grown because of the advantages of targeting cellular receptors in vivo with high sensitivity as well as specificity and treatment at the molecular level. Recent advances in molecular biology have not only stimulated advances in PRRT in a sustainable manner but have also pushed the field significantly forward to several unexplored possibilities. Recent decades have witnessed unprecedented endeavors for developing radiolabeled receptor-binding somatostatin analogs for the treatment of neuroendocrine tumors, which have played an important role in the evolution of PRRT and paved the way for the development of other receptor-targeting peptides. Several peptides targeting a variety of receptors have been identified, demonstrating their potential to catalyze breakthroughs in PRRT. In this review, the authors discuss several of these peptides and their analogs with regard to their applications and potential in radionuclide therapy. The advancement in the availability of combinatorial peptide libraries for peptide designing and screening provides the capability of regulating immunogenicity and chemical manipulability. Moreover, the availability of a wide range of bifunctional chelating agents opens up the scope of convenient radiolabeling. For these reasons, it would be possible to envision a future where the scope of PRRT can be tailored for patient-specific application. While PRRT lies at the interface between many disciplines, this technology is inextricably linked to the availability of the therapeutic radionuclides of required quality and activity levels and hence their production is also reviewed.

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“…This accumulation compares favourably with the 10.5% ID/g of 125 I-FIAU and 0.15% ID/g of 18 F-FHPG [(3-fluoro-1-hydroxy-2-propoxy) methyl guanine] reported for a similar model using the TK expressing murine fibrosarcoma cell line CMS-STK in BALB/c mice [33]. The specific accumulation of radioactivity at 4 h is 22% ID/g (calculated by subtracting the non-specific accumulation of radioactivity in non-transduced 9L tumours from the total radioactivity measured in the 9L-TK tumours) and is higher than the specific accumulation obtained with either 125 I-FIAU (9.8% ID/g) or 18 F-FHPG (0.08% ID/g) [33]. Four hours after tracer injection, the ratios of 123 I-FIRU uptake in tumour to blood, muscle and brain were 19.4, 32.3 and 171.6 respectively.…”

Section: Discussionmentioning

confidence: 92%

“…Like other nucleoside analogues, FIRU can be labelled with radioactive iodine isotopes for single-photon emission tomography (SPET) or positron emission tomography (PET) imaging. Iodine-123 was chosen for imaging in these studies because of the 13.3-h half-life and favourable imaging characteristics [18]. In the present study we demonstrate that 123 I-labelled FIRU in combination with a gamma camera is a valuable tracer for imaging HSV1-tk gene expression.…”

Section: Introductionmentioning

confidence: 95%

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Imaging expression of adenoviral HSV1-tk suicide gene transfer using the nucleoside analogue FIRU

et al. 2002

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Substrates for monitoring HSV1-tk gene expression include uracil and acycloguanosine derivatives. The most commonly used uracil derivative to monitor HSV1-tk gene transfer is 1-(2-fluoro-2-deoxy--D-arabinofuranosyl)-5-[*I]iodouracil (fialuridine; I*-FIAU), where the asterisk denotes any of the radioactive iodine isotopes that can be used. We have previously studied other nucleosides with imaging properties as good as or better than FIAU, including 1-(2-fluoro-2-deoxy--D-ribofuranosyl)-5-[*I]iodouracil (FIRU). The first aim of this study was to extend the biodistribution data of 123I-labelled FIRU. Secondly, we assessed the feasibility of detecting differences in HSV1-tk gene expression levels following adenoviral gene transfer in vivo with 123I-FIRU. 9L rat gliosarcoma cells were stably transfected with the HSV1-tk gene (9L-tk+). 123I-FIRU was prepared by radioiodination of 1-(2-fluoro-2-deoxy--D-ribofuranosyl)-5-tributylstannyl uracil (FTMRSU; precursor compound) and purified using an activated Sep-Pak column. Incubation of 9L-tk+ cells and the parental 9L cells with 123I-FIRU resulted in a 100-fold higher accumulation of radioactivity in the 9L-tk+ cells after an optimum incubation time of 4 h. NIH-bg-nu-xid mice were then inoculated subcutaneously with HSV1-tk (-) 9L cells or HSV1-tk (+) 9L-tk+ cells into both flanks. Biodistribution studies and gamma camera imaging were performed at 15 min and 1, 2, 4 and 24 h p.i. At 15 min, the tumour/muscle, tumour/blood and tumour/brain ratios were 5.2, 1.0 and 30.3 respectively. Rapid renal clearance of the tracer from the body resulted in increasing tumour/muscle, tumour/blood and tumour/brain ratios, reaching values of 32.2, 12.5 and 171.6 at 4 h p.i. A maximum specific activity of 22%ID/g tissue was reached in the 9L-tk+ tumours 4 h after 123I-FIRU injection. Two Ad5-based adenoviral vectors containing the HSV1-tk gene were constructed: a replication-incompetent vector with the transgene in the former E1 region, driven by a modified CMV promoter, and a novel replication-competent vector with the HSV1-tk gene in E3 driven by the natural E3 promoter. The human glioma cell lines U87MG and T98G were infected with a multiplicity of infection (m.o.i.) of 10. Forty-eight hours later the cells were incubated with 123I-FIRU and radioactivity was measured in a gamma counter. We found significantly higher levels of radioactivity in both cell lines following infection with the replication-competent vector (P<0.001). NIH-bg-nu-xid mice were then inoculated subcutaneously with U87MG cells. Tumours (approximately 1,000 mm3) were injected with 108 and 109 Infectious Units (I.U.) of either vector. After 48 h, the tracer was injected, followed by gamma camera imaging and direct measurement of radioactivity in the tumours at 4 h p.i. Images and direct measurements indicated increased uptake of tracer with higher I.U. and also demonstrated increased accumulation of tracer in the tumours treated with the replication-competent adenoviral vector (P=0.03). These results demonstrate that 123I...

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Iodine-131 labelled octreotide: not an option for somatostatin receptor therapy

Cited by 23 publications

References 20 publications

Ascorbic Acid Stabilization of Re-188- and I-131-Radiolabeled Peptides for Radiotherapy

Ascorbic Acid Stabilization of Re-188- and I-131-Radiolabeled Peptides for Radiotherapy

Peptide Receptor Radionuclide Therapy: An Overview

Imaging expression of adenoviral HSV1-tk suicide gene transfer using the nucleoside analogue FIRU

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