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

Somatostatin is a regulatory peptide implicated in the control of cellular proliferation in epithelial tissues and this regulation may occur directly via membrane bound receptor activation. The aim of this study was to investigate somatostatin binding in human gastrointestinal cancer and normal mucosa. Plasma membranes were prepared from specimens of tumour and normal mucosa from 51 patients undergoing surgical resection for malignancy (28 gastric, 23 colorectal). Using a competitive displacement assay, specific 125I-tyrosine-11-somatostatin-14 binding to plasma membranes was assessed and and characterised in terms of receptor affinity (Kd) and maximum binding capacity (Bmax) as determined by Scatchard analysis. Specific low affinity (Kd = 166 nM), high capacity (Bmax = 1.2 pmol mg-1 protein) somatostatin binding was demonstrated in 22 of the gastric cancers and 17 of the colorectal cancers (Kd = 140 nM, Bmax = 1.8 pmol mg-1 protein). Similar affinity and binding capacity was demonstrable in normal mucosal samples. High affinity receptors for somatostatin were expressed by one gastric carcinoma (Kd = 0.9 nM; Bmax = 0.23 pmol mg-1 protein). Thus, low affinity, high capacity binding is a common feature of gastrointestinal tumours and normal mucosa, and high affinity receptors may occasionally be demonstrated. The functional significance of these low affinity binding sites requires elucidation to determine whether long-acting somatostatin analogues may have therapeutic benefit in gastrointestinal malignancy.
 ...
PMID:Somatostatin binding in normal and malignant human gastrointestinal mucosa. 135 73

The hypothesis that somatostatin, a compound with antitrophic effects on the gastrointestinal tract, may affect beneficially the progression of advanced intestinal cancer has been tested in a small pilot study. Ten patients, four with advanced pancreatic cancer, four with advanced colorectal cancer and two with gastric cancer, were treated with a long-acting analogue of somatostatin, SMS 201-995, 50, 100 micrograms subcutaneously twice daily. There were no clinical, radiological or biochemical indicators of a response to this treatment. There are no indications from this study that hormonal manipulation alters the rate of growth of advanced gastrointestinal cancer.
 ...
PMID:SMS 201-995 treatment and advanced intestinal cancer: a pilot study. 297 16

Octreotide, a somatostatin analogue, has been shown to inhibit the growth of gastrointestinal cancers in vitro and in vivo. To assess the anti-tumour effect of octreotide, we performed a randomised trial comparing octreotide with best supportive care in advanced gastrointestinal cancer patients refractory to chemotherapy. A total of 107 patients with advanced gastrointestinal cancer refractory to chemotherapy were randomised to receive octreotide at the dose of 200 micrograms three times a day for 5 days a week, or the best supportive care only. The primary outcome variable was the survival duration. Response rate was an outcome variable of secondary importance. Fifty-five patients (15 stomach, 16 pancreas, 24 colon-rectum) received octreotide, while 52 (14 stomach, 16 pancreas, 22 colon-rectum) received the best supportive care. Patients treated with octreotide had a significant advantage in duration of survival with a median survival time of 20 weeks vs 11 in the control group (P < 0.0001). This advantage was present also considering the survival data for each tumour group. Twenty-five patients (45%) given octreotide showed stable disease vs only eight (15%) in the control group (P < 0.001). In conclusion, octreotide therapy seems to confer a survival benefit in advanced gastrointestinal cancer patients refractory to chemotherapy. Additional studies will be needed to confirm these results and to clarify other questions about dose and schedule of octreotide.
 ...
PMID:A randomised trial of octreotide vs best supportive care only in advanced gastrointestinal cancer patients refractory to chemotherapy. 781 50

This study characterises the somatostatin binding site in human gastrointestinal cancer and mucosa in terms of cationic specificity and relative affinity for three somatostatin analogues. Competitive displacement assays were performed on plasma membranes from human gastric and colonic tissues using radiolabelled somatostatin-14 as ligand. Comparison was made with the somatostatin binding site in rat cerebral cortex. In gastrointestinal tissue, magnesium decreased and sodium increased specific binding. By contrast, in rat cerebral cortex, the converse cationic effect was seen. These changes resulted from alterations in receptor density, with no change in receptor affinity. Displacement studies were then performed with somatostatin-14 and somatostatin analogues RC-160, somatuline, and octreotide. RC-160 and somatuline displaced radiolabel from binding sites in gastric and colonic cancer and mucosa with 10-fold lower affinity than the native peptide. Octreotide did not displace radioligand in gastric or colonic cancer at any concentration tested. By contrast, in rat cortex, although all three analogues displaced with a lower affinity than the native peptide, there was no difference between analogues. These data suggest a distinct somatostatin receptor subtype in gastrointestinal tissues.
 ...
PMID:Somatostatin binding in human gastrointestinal tissues: effect of cations and somatostatin analogues. 790 9

Surgical excision has been the mainstay of treatment for neuroendocrine tumors of the pancreas (PNET). Compounds like streptozocin and dacarbazin have been traditionally used in inoperable cases and somatostatin to treat syndromes deriving from functional tumors. However, a lot of progress has taken place in the area of molecular characterization of these tumors, revealing activation of mammalian target of rapamycin (mTOR) and VEGF pathways. Recent data from the 2010 ASCO Gastrointestinal Cancers Symposium demonstrate antitumor activity of everolimus, an mTOR inhibitor in combination with temozolomide in a phase I/II trial and of sunitinib versus placebo in a randomized double blinded phase III trial. The role of modern biologic compounds in the treatment of PNET is not clear yet. In addition, combination of resection and transarterial chemoembolization (TACE) has been proven effective over either modality alone in the treatment of PNET metastatic to the liver in a retrospective analysis. This comes to address the problem of selecting local intervention in a metastatic disease, which has been a reasonable choice for this group of tumors in the past. Last but not least the role of Ki-67 in decision-making in PNET is being discussed.
 ...
PMID:Neuroendocrine tumors of the pancreas: what's new. Highlights from the "2010 ASCO Gastrointestinal Cancers Symposium". Orlando, FL, USA. January 22-24, 2010. 2020 21

Somatostatin receptors of human gastrointestinal cancer specimens and cell lines were measured using in vitro film autoradiography. Four colon and one gastric cancer cell lines when grown as xenografts were receptor-positive. Of the 31 human colorectal cancers, forty percent were receptor-positive, and there was an association between advanced stage and poorer differentiation with receptor status. Biopsy specimens of two gastric, one pancreatic and one esophageal cancers were negative for somatostatin receptors.
 ...
PMID:Somatostatin receptors in human gastrointestinal cancer. 2157 94

Pancreatic cancer still is a significant, unresolved therapeutic challenge with nearly similar incidence and mortality rates. It is the most lethal type of digestive cancer with a 5-year survival rate of 5%. Adjuvant chemotherapy remains to be gemcitabine alone or combined with infusional 5-fluorouracil with radiation therapy. Nevertheless, only a few patients survive for at least 5 years after R0 resection and adjuvant therapy. Most patients need palliative treatment. Once pancreatic cancer becomes metastatic, it is uniformly fatal with an overall survival of typically 6 months from diagnosis. Chemotherapy is an important component of palliative care but must be administered as a part of a multidisciplinary approach, including palliation of pain, managing weight loss, and deterioration in functional status. Gemcitabine has been the standard in both locally advanced and metastatic disease. The addition of the tyrosine kinase inhibitor erlotinib prolongs median survival for only 2 weeks. While gemcitabine-based regimens are currently accepted as the standard first-line treatment of patients with locally advanced or metastatic pancreatic adenocarcinoma, there is no consensus regarding treatment in the second-line setting. It will not be untrue to say that there are no real medical breakthroughs with regards to improving the prognosis of pancreatic cancer as of 2011. On the other hand, we have made some progress in patients with advanced pancreatic neuroendocrine tumors. These patients have a 5-year survival that can range from 97% in benign insulinomas to as low as 30% in non-functional metastatic pancreatic neuroendocrine tumors. Treatment options may include surgery, transarterial chemoembolization of liver metastases, and cytotoxic therapy such as streptozotocin, 5-fluorouracil or doxorubicin. Somatostatin analogues, like octreotide, have been proven to prolong progression-free survival in patients with metastatic neuroendocrine tumors of midgut origin. In 2011, two targeted agents, a tyrosine kinase inhibitor sunitinib and mTOR inhibitor everolimus have been approved by FDA for pancreatic neuroendocrine tumors. With these approvals, U.S. physicians can now offer their patients with progressive pancreatic neuroendocrine tumors. Patients with any stage of pancreatic cancer should be considered candidates for clinical trials.
 ...
PMID:Pancreatic neoplasm in 2011: an update. 2173 86

Gastrin has been identified as the principal effector of gastric secretion, but several studies have demonstrated its role as a biomarker of cancer risk and as a growth factor for colorectal, stomach, liver, and pancreatic cancer. Hypergastrinemia characterizes autoimmune gastritis, with body and fundic gland atrophy and increased risk for both gastric adenocarcinoma and neuroendocrine tumors. Gastric type I carcinoids develop in the context of autoimmune gastritis because of the stimulus exerted by gastrin on enterochromaffin-like cells and remain gastrin-sensitive for long durations because the removal of hypergastrinemia leads to tumor regression. The treatment of gastric carcinoid is still open to debate, but when the disease frequently relapses, or is multicentric or infiltrating, surgery is advocated or, in the alternative, a costly and long-lasting treatment with long-acting somatostatin analogues is prescribed. A technology allowing the preparation of an immunogen eliciting an immune system response with generation of antibodies against G17 has been developed. This vaccine has been tested in patients with colorectal, pancreatic or advanced gastric cancer. The vaccine has also been used in the treatment of gastric type I carcinoids, and the administration of G17DT in patients harboring these lesions leads to carcinoid regression. Antigastrin vaccination in the treatment of gastrointestinal cancer obviously needs validation, but this immunotherapy may well represent a simple, inexpensive, and active 'adjuvant' treatment.
...
PMID:Gastrin: from pathophysiology to cancer prevention and treatment. 2446 63

Pancreatic neuroendocrine tumors (pNETs) are rare well-differentiated neoplasms which can be functional or non-functional. They tend to have a worse prognosis than their counterpart carcinoid tumors. Current systemic treatment options for advanced, unresectable disease include somatostatin analogs, everolimus and sunitinib. Low response rates and toxicity profiles have, thus far, limited the widespread use of cytotoxic chemotherapy in this setting. In this update, we review three abstracts from the 2014 ASCO Gastrointestinal Cancers Symposium that present outcomes of the use of combination capecitabine and temozolomide in patients with advanced pNET. We summarize their results and discuss the role of this regimen in treatment algorithms for metastatic pNET.
...
PMID:Pancreatic neuroendocrine tumors: does chemotherapy work? 2461 36

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are rare malignancies that originate in the gastrointestinal system. GEP-NETs are typically indolent, but tumors known as "functional" secrete hormones that can lead to a complex of symptoms, including flushing, diarrhea, bronchospasm, and valvular heart disease. Management of patients with GEP-NETs requires a multidisciplinary approach, as treatment modalities include surgery, radiology, and pharmacotherapy. The available pharmacologic agents have increased in recently, and now include cytotoxic chemotherapies, somatostatin analogues, multitargeted tyrosine kinase inhibitors, mammalian target of rapamycin inhibitors, and radioisotopic radiotherapies. The optimal sequencing of treatments is unknown. Advances in the management of GEP-NETs have been based on the results of recently completed clinical trials that have shown improvement in disease outcome and symptom management. The amount of positive data that has emerged from these studies is unprecedented in the GEP-NETs field. At the 2017 American Society of Clinical Oncology Gastrointestinal Cancers Symposium, several abstracts provided subanalyses of previous trials and new data for emerging treatments. Management will likely evolve as these therapies are incorporated into clinical care.
 ...
PMID:Recent advances in the management of gastroenteropancreatic neuroendocrine tumors: insights from the 2017 ASCO Gastrointestinal Cancers Symposium. 2865 22


1 2 Next >>