Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P61278 (somatostatin)
 22,083 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The authors evaluated the presence of somatostatin (SRIF) in the plasma and in the tumor tissue of a total of 22 patients with medullary thyroid cancer (MTC) and studied the effect of exogenous SRIF administration on basal and pentagastrin (PG)-stimulated plasma calcitonin (CT) and carcinoembryonic antigen (CEA) levels. Mean plasma SRIF concentrations were significantly higher than those found in normal controls, with five of 15 patients having plasma SRIF levels above the mean + 2 SD of normal controls. High immunoreactive SRIF concentrations were found in the extract of three tumor tissues but not in one follicular thyroid cancer or in one toxic diffuse goiter. By immunoperoxidase staining seven of 11 (63.6%) primary MTC and five of 13 (38.5%) metastases expressed SRIF antigen in a low number of cells and with a weak degree of staining. As expected, CT was expressed in almost 100% of the cases with positivity in most of the cells and strong degree of staining. Patients with positive SRIF staining in the primary tumor had longer survival than SRIF negative patients. Infusion of synthetic SRIF (11 micrograms/minute/45 minutes) produced a significant reduction of plasma CT (but not CEA) levels in 12 of the 15 patients submitted to this test. Maximal percent decrease of plasma CT ranged from 10.8% to 72.7% of the basal value and was usually observed between 30 and 45 minutes from the beginning of the infusion. When infused together with the injection of PG, SRIF was able to significantly (P less than 0.05) inhibit the PG-induced CT release in five of six patients tested. These results demonstrate the following: SRIF is present in a few cells of many primary MTC and less frequently in their metastases; tentatively, the expression of SRIF antigen in the tumor seems to be associated with longer survival; increased SRIF concentrations are found in the plasma of some patients with metastatic involvement; and treatment with exogenous SRIF reduces the basal and PG-induced CT (but not CEA) release from the tumor.
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PMID:Somatostatin in medullary thyroid cancer. In vitro and in vivo studies. 256 68

Somatostatin and its analogs are antiproliferative in a wide range of normal and neoplastic tissues. In this study we investigated the effect of octreotide (SMS 201-995) on the invasion and growth of three follicular thyroid cancer (FTC) cell lines from one patient in vitro and in vivo. FTC133 was established from the primary tumor, FTC236 from a cervical lymph node metastasis, and FTC238 from a lung metastasis. Invasion was the ability of tumor cells to penetrate 8-microns pore polycarbonate membranes coated with Matrigel. Invasion and proliferation were analyzed using the MTT assay. For in vivo experiments, athymic nude mice were sc inoculated with 500,000 calls of FTC133. The animals were treated twice daily with octreotide sc (100-300 micrograms/kg). RIA studies yielded dose-dependent high plasma levels of octreotide (3.43-6.5 ng/mL). Octreotide had a biphasic effect, enhancing growth at low concentrations (1-10 nmol/mL) and inhibiting it at high concentrations (100 nmol to 1 mumol/mL). Octreotide had also a dose-dependent biphasic effect on the invasion of FTC, inhibiting the invasion of all follicular thyroid cancer lines at high concentrations. However, it affected invasion less than growth. Octreotide (10 nmol/mL) stimulated the invasion of FTC133 by 13%, whereas stimulation was lower in both FTC metastases (FTC236, 6%; FTC238, 7%; P < 0.01). At higher concentrations (100 nmol to 1 mumol/mL), octreotide inhibited invasion of FTC133 by 17% (FTC236, 15%; FTC238, 17%; P < 0.01). During a 3-week treatment period, octreotide had no antiproliferative effect on the growth of FTC133 cells in nude mice. In conclusion, octreotide at low concentrations stimulates and at high concentrations inhibits the growth and invasion of follicular thyroid cancer cells in culture. However, it has no effect on the growth of FTC cells in animal experiments. Thus, the value of octreotide as an antitumoral agent in follicular thyroid cancer must be critically questioned.
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PMID:Somatostatin analog octreotide inhibits the growth of differentiated thyroid cancer cells in vitro, but not in vivo. 867 90

Somatostatin receptors (SSTR) are expressed in various endocrine tumours. The expression of SSTR at the tumour cell surface confers the possibility for diagnostic imaging and therapy of tumours using radiolabeled somatostatin analogues. The majority of currently available somatostatin analogues show a higher binding affinity for the SSTR2 subtype. To date, the precise expression pattern of the SSTR subtypes 1-5 in thyroid epithelial tumours remains to be determined. We investigated the mRNA expression of SSTR1-5 in benign and malignant epithelial thyroid tumours [20 cold thyroid nodules (CTNs), 20 toxic thyroid nodules (TTNs), 20 papillary, 20 follicular, and 5 anaplastic carcinomas (PTCs, FTCs, ATCs, respectively)] and compared them to normal surrounding thyroid tissues. Four out of five SSTR subtypes were detected in malignant thyroid tumours, benign neoplasia, and normal surrounding tissue with a predominant expression of SSTR2 and SSTR5, and a weak expression of SSTR1 and SSTR3. Weak SSTR4 mRNA expression was detected in some PTCs. Compared to normal thyroid tissue, SSTR2 was significantly upregulated in PTC and ATC. In addition significant upregulation of SSTR3 was found in PTC. SSTR5 mRNA expression was increased in PTC and FTC and significantly decreased in CTN and TTN compared to normal thyroid tissue. SSTR2 is the predominant subtype in thyroid epithelial tumours with a high expression pattern, in particular, in PTC . Perspectively, the expression of distinct SSTR in thyroid epithelial tumours might represent a promising avenue for diagnostics and therapy of advanced thyroid cancer with somatostatin analogues.
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PMID:Somatostatin receptor subtype expression in human thyroid tumours. 2009 70