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| 2. |
- Jakobsen, A M, et al.
(författare)
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Differential expression of vesicular monoamine transporter (VMAT) 1 and 2 in gastrointestinal endocrine tumours.
- 2001
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Ingår i: The Journal of pathology. - : Wiley. - 0022-3417. ; 195:4, s. 463-72
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Tidskriftsartikel (refereegranskat)abstract
- Neuroendocrine tumours are characterized by their capacity to produce hormones, which are stored in vesicles and secretory granules. Demonstration of granule/vesicle proteins in tumours is taken as evidence of neuroendocrine differentiation. Vesicular monoamine transporters (VMAT1 and VMAT2) mediate the transport of amines into vesicles of neurons and endocrine cells. The expression of VMAT1 and VMAT2 and the usefulness of VMAT1 and VMAT2 in the histopathological diagnosis of gastrointestinal endocrine tumours have not been fully explored. This study therefore investigated the expression of VMAT1 and VMAT2 in 211 human gastrointestinal tumours by immunocytochemistry and western blotting. VMAT1 and/or VMAT2 were demonstrated in the majority of amine-producing endocrine tumours of gastric, ileal, and appendiceal origin. Serotonin-producing endocrine tumours (ileal and appendiceal carcinoids) expressed predominantly VMAT1, while histamine-producing endocrine tumours (gastric carcinoids) expressed VMAT2 almost exclusively. In peptide-producing endocrine tumours such as rectal carcinoids and endocrine pancreatic tumours, only a small number of immunopositive tumour cells were observed. No labelling was found in non-endocrine tumours, including gastric, colorectal and pancreatic adenocarcinomas and gastrointestinal stromal tumours. In conclusion, VMAT1 and VMAT2 are differentially expressed by gastrointestinal endocrine tumours, with a pattern specific for each tumour type, reflecting their neuroendocrine differentiation and origin. VMAT1 and VMAT2 may therefore become valuable markers in the classification of neuroendocrine tumours and may also indicate patients suitable for radioisotope treatment operating via these transporter systems.
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| 3. |
- Kölby, Lars, 1963, et al.
(författare)
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A transplantable human carcinoid as model for somatostatin receptor-mediated and amine transporter-mediated radionuclide uptake.
- 2001
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Ingår i: The American journal of pathology. - 0002-9440. ; 158:2, s. 745-55
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Tidskriftsartikel (refereegranskat)abstract
- A human midgut carcinoid tumor was successfully transplanted into nude mice and propagated for five consecutive generations (30 months) with well-preserved phenotype. Tumor cells in nude mice expressed identical neuroendocrine markers as the original tumor, including somatostatin receptors (somatostatin receptors 1 to 5) and vesicular monoamine transporters (VMAT1 and VMAT2). Because of the expression of somatostatin receptors and VMAT1 and VMAT2 the grafted tumors could be visualized scintigraphically using the somatostatin analogue 111In-octreotide and the catecholamine analogue 123I-metaiodobenzylguanidine. The biokinetics of the somatostatin analogue 111In-octreotide in the tumors was studied and showed a high retention 7 days after administration. Cell cultures were re-established from transplanted tumors. Immunocytochemical and ultrastructural studies confirmed the neuroendocrine differentiation. The human origin of transplanted tumor cells was confirmed by cytogenetic and fluorescence it situ hybridization analyses. Spontaneous secretion of serotonin and its metabolite, 5-hydroxyindole acetic acid, from tumor cells was demonstrated. The tumor cells increased their [Ca2+]i in response to beta-adrenoceptor stimulation (isoproterenol) and K+-depolarization. All somatostatin receptor subtypes could be demonstrated in cultured cells. This human transplantable carcinoid tumor, designated GOT1, grafted to nude mice, will give unique possibilities for studies of somatostatin receptor- and VMAT-mediated radionuclide uptake as well as for studies of secretory mechanisms.
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| 4. |
- Kölby, Lars, 1963, et al.
(författare)
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Chromogranin A as a determinant of midgut carcinoid tumour volume
- 2004
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Ingår i: Regulatory peptides. - : Elsevier BV. - 0167-0115. ; 120:1-3, s. 269-73
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Tidskriftsartikel (refereegranskat)abstract
- Neuroendocrine (NE) tumours are characterized by their capacity to synthesize, store and release hormonal products. These substances are stored in neurosecretory vesicles together with chromogranin A (CgA). The concentration of plasma CgA in patients with NE tumours is thought to reflect the degree of NE differentiation, total tumour burden and effect of medical treatment. The aim of this study was to analyse the correlation between tumour weight and plasma CgA levels as well as the influence of treatment with a long-acting somatostatin analogue (octreotide) using nude mice with xenografted human ileal carcinoid tumours. There was a correlation between tumour weight and plasma CgA levels in all animals (p < 0.00001). In octreotide-treated mice, plasma CgA levels were significantly reduced versus untreated animals (p = 0.037). In conclusion, this study demonstrates that plasma CgA levels are closely correlated to tumour burden, and that plasma CgA is well suited for monitoring the clinical course and outcome of treatment in patients with NE tumours.
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| 5. |
- Kölby, Lars, 1963, et al.
(författare)
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Uptake of meta-iodobenzylguanidine in neuroendocrine tumours is mediated by vesicular monoamine transporters.
- 2003
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Ingår i: British journal of cancer. - : Springer Science and Business Media LLC. - 0007-0920 .- 1532-1827. ; 89:7, s. 1383-8
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Tidskriftsartikel (refereegranskat)abstract
- The radio-iodinated noradrenaline analogue meta-iodobenzylguanidine (MIBG) can be used for scintigraphy and radiation therapy of neuroendocrine (NE). The aim of the present study was to study the importance of vesicular monoamine transporters (VMATs) for the uptake of (123)I-MIBG in NE tumours. In nude mice, bearing the human transplantable midgut carcinoid GOT1, all organs and xenografted tumours accumulated (123)I after i.v. injection of (123)I-MIBG. A high concentration of (123)I was maintained in GOT1 tumours and adrenals, which expressed VMATs, but rapidly decreased in all other tissues. In the VMAT-expressing NE tumour cell lines GOT1 and BON and in VMAT-expressing primary NE tumour cell cultures (carcinoids, n=4 and pheochromocytomas, n=4), reserpine significantly reduced the uptake of (123)I-MIBG. The membrane pump inhibitor clomipramine had no effect on the uptake of (123)I-MIBG in GOT1 and BON cells, but inhibited the uptake in one out of four primary carcinoid cell cultures and three out of four primary pheochromocytoma cell cultures. In conclusion, VMATs and secretory granules are of importance for the uptake and retention of (123)I-MIBG in NE tumours. Information about the type and degree of expression of VMATs in NE tumours may be helpful in future to select patients suitable for radiation therapy with radio-iodinated MIBG.
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| 7. |
- Nilsson, Ola, 1957, et al.
(författare)
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GOT1 xenografted to nude mice: a unique model for in vivo studies on SSTR-mediated radiation therapy of carcinoid tumors
- 2004
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Ingår i: Annals of the New York Academy of Sciences. - 0077-8923. ; 1014, s. 275-9
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Tidskriftsartikel (refereegranskat)abstract
- Malignant carcinoid tumors express high numbers of somatostatin receptors. Radiation therapy using labeled somatostatin analogs is a novel treatment modality for these tumors. We have analyzed the biokinetics and therapeutic effect of radiolabeled somatostatin analog on a human midgut carcinoid grafted to nude mice. A transplantable human midgut carcinoid (GOT1) was grafted to the back of nude mice. Tumor-bearing mice were injected with (111)In-DTPA-D-Phe(1)-octreotide, followed by measurement of (111)In activity concentration ratios in tumor tissues. Tumor-bearing mice were also injected with (177)Lu-DOTA-Tyr(3)-octreotate and followed for 7 days. The concentration of (111)In-DTPA-D-Phe(1)-octreotide in tumor tissues was very high 4 hours postinjection with 0.4-13% of injected activity per gram. Injection of 30-120 MBq (177)Lu-DOTA-Tyr(3)-octreotate reduced tumor volume to 7-14% of the original tumor volume 7 days postinjection. Microscopic analysis of treated tumors revealed widespread areas of tumor cell necrosis and fibrosis. It was found that grafted GOT1 cells to nude mice represent an authentic model for studying human midgut carcinoids. Radiolabeled somatostatin analogs have a high selectivity for tumor tissue and can induce tumor cell necrosis. Radiotherapy of carcinoid tumors with (177)Lu-DOTA-Tyr(3)-octreotate appears to be a promising treatment modality for either palliative treatment or completion therapy after attempted surgical cure.
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| 8. |
- Nilsson, Ola, 1957, et al.
(författare)
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Importance of vesicle proteins in the diagnosis and treatment of neuroendocrine tumors.
- 2004
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Ingår i: Annals of the New York Academy of Sciences. - : Wiley. - 0077-8923 .- 1749-6632. ; 1014, s. 280-3
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Tidskriftsartikel (refereegranskat)abstract
- We have analyzed the expression of synaptic vesicle proteins in human neuroendocrine tumors and the potential use of vesicle proteins in the diagnosis and treatment of neuroendocrine tumors. Biopsies from endocrine and nonendocrine tumors of the gastrointestinal tract, pancreas, and adrenals were examined by immunocytochemistry using antibodies against synaptic vesicle protein 2 (SV2), vesicular monoamine transporter 1 and 2 (VMAT1 and 2), and neuroendocrine secretory protein 55 (NESP55). SV2 was expressed in all endocrine tumors of the gastrointestinal tract and pancreas as well as in gastrointestinal stromal tumors (GISTs). None of the adenocarcinomas expressed SV2. VMAT1 and 2 were expressed in amine-producing tumors of the gastrointestinal tract (ECL cell and EC cell carcinoids) and in a small number of peptide-producing pancreatic endocrine tumors. NESP55 was expressed in neuroblastomas and adrenal pheochromocytomas as well as in a subgroup of pancreatic endocrine tumors. The importance of VMAT1 and 2 for the uptake of 123I-MIBG in tumor cells was demonstrated. It was concluded that neuroendocrine tumors express multiple synaptic vesicle proteins that are useful in the histopathological diagnosis and classification of tumors. Vesicle proteins may prove to be useful for targeting tumor therapy.
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| 9. |
- Schmitt, Anneli, 1971, et al.
(författare)
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Radiation therapy of small cell lung cancer with 177Lu-DOTA-Tyr3-octreotate in an animal model
- 2004
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Ingår i: Journal of nuclear medicine. - 0161-5505. ; 45:9, s. 1542-8
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Tidskriftsartikel (refereegranskat)abstract
- Small cell lung cancer (SCLC) is a tumor of neuroendocrine (NE) origin with very low survival rate. Somatostatin receptor scintigraphy using 111In-DTPA-octreotide (DTPA is diethylenetriaminepentaacetic acid) is a well-established method for the visualization of somatostatin receptor-expressing NE tumors. Recently, new combinations of radionuclides and somatostatin analogs have been investigated for therapeutic purposes. In this study, the somatostatin analog DOTA-Tyr3-octreotate (DOTA is 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid), labeled with the medium-energy electron emitter 177Lu (maximal electron energy = 498 keV, half-life = 6.6 d), was used for radiation therapy of human SCLC in an animal model. METHODS: Nude mice, bearing tumors from the human SCLC cell line NCI-H69, were injected intravenously with 177Lu-DOTA-Tyr3-octreotate. Groups of animals (n = 5 or 6) were injected with 45-, 60-, and 120-MBq fractions and two 45-MBq fractions 48 h apart. Furthermore, 1 control group was treated with unlabeled DOTA-Tyr3-octreotate and another control group was not treated. RESULTS: In both control groups, the tumor volumes were increased 2-fold in approximately 5 d. Treatment with 177Lu-DOTA-Tyr3-octreotate resulted in marked tumor regression with statistically significant tumor volume reduction after 1 wk (P < 0.001). The tumor growth delay time was dependent on the amount of injected activity for the groups with single injections, 26 d for 60 MBq and 40 d for 120 MBq. The best therapeutic effect was obtained in mice injected with 2 fractions of 45 MBq. The relative tumor volume after 1 mo was 0.004 +/- 0.004. CONCLUSION: Radiation therapy with 177Lu-DOTA-Tyr3-octreotate on SCLC-bearing mice was successful. Since the experiments were performed on a human SCLC cell line xenografted to nude mice, the results may be clinically relevant and treatment with 177Lu-DOTA-Tyr3-octreotate could be a treatment alternative in this tumor disease that normally has a dismal prognosis.
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