Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01189 (beta-endorphin)
 21,003 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The long-acting analogues of somatostatin have an established place in the medical treatment of patients with neuroendocrine tumours. They act through binding with specific, high-affinity membrane receptors. Somatostatin analogue therapy is an effective and safe treatment for most growth hormone and thyrothropin-secreting pituitary adenomas. The potential therapeutic consequences of the presence of somatostatin receptors on clinically 'nonfunctioning' pituitary tumours are still uncertain. Somatostatin analogues are not useful in the treatment of patients with prolactinomas, or adrenocorticotropin (ACTH)-secreting adenomas. However, the somatostatin analogue octreotide suppressed pathological ACTH release in some patients with Nelson's syndrome and ACTH and cortisol secretion in several patients with Cushing's syndrome caused by ectopic ACTH secretion. Somatostatin analogues are effective in the sympatomatic treatment of most (metastatic) pancreatic islet cell tumours and most (metastatic) carcinoids. In some of these patients, they also induce tumour stabilisation or reduction. In some patients with (metastatic) medullary thyroid carcinomas, continuous treatment with very high doses of octreotide can be of temporary relief. The clinical effectiveness of somatostatin analogues in patients with small cell lung cancer is currently under investigation. Long-term therapy with somatostatin analogues of catecholamine-secreting (malignant) paragangliomas and phaeochromocytomas has not shown clinical benefits.
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PMID:Somatostatin analogue treatment of neuroendocrine tumours. 893 99

Non-pituitary tumors that produce adrenocorticotropic hormone (ACTH) exhibit resistance to the normal feedback effects of glucocorticoids on proopiomelanocortin (POMC) gene expression. This glucocorticoid resistance is typically complete, although some tumors show only relative glucocorticoid resistance in the clinical setting. The molecular mechanisms responsible for these clinical pathophysiologic observations are unknown, but might include glucocorticoid receptor defects or aberrant expression of enzymes or transporters that exclude glucocorticoids from access to their intracellular receptors. We examined whether ACTH-producing non-pituitary tumor cells might express 11beta-hydroxysteroid dehydrogenase (11beta-HSD), the principal 'gatekeeper' enzyme known to metabolize glucocorticoids. 11Beta-HSD mRNA and enzyme activity were assessed in DMS-79 cells, a line derived from an ACTH-producing small cell lung cancer. RT-PCR studies showed expression of mRNA encoding 11beta-HSD2 but not 11beta-HSD1 in DMS-79 cells. Control human fibroblasts expressed predominantly 11beta-HSD1 but also had detectable 11beta-HSD2 mRNA, while HepG2 hepatoma cells also expressed only 11beta-HSD2 mRNA. Whole cell assays in DMS-79 cells revealed 11beta-HSD activity with a Km for cortisol of 26.1 +/- 9.0 nM and Vmax of 57.0 +/- 5.9 pmol/h/mg protein. HepG2 cells expressed a similar high affinity enzyme activity, while control fibroblasts expressed 11beta-HSD activity with a Km for cortisol of 652 nM. Conversion of cortisol to cortisone in DMS-79 cells was inhibited to 7% of baseline by addition of 10 microM glycyrrhetinic acid. Dexamethasone (20 nM) was converted to a single product in DMS-79 cells at a rate of 17.2 pmol/h/mg protein; this activity was also inhibited by glycyrrhetinic acid. We conclude that DMS-79 cells express 11beta-HSD2. While DMS-79 cells harbor additional defects in glucocorticoid signaling, these data suggest that expression of 11beta-HSD2 might contribute to the development of the glucocorticoid-resistant phenotype of some ACTH-producing tumors.
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PMID:Expression of 11beta-hydroxysteroid dehydrogenase type 2 in an ACTH-producing small cell lung cancer. 988 91

DNA microarray techniques were used to compare gene expression in an adrenocorticotropin (ACTH)-producing human small cell lung carcinoma line (DMS-79) with six other small cell lung cancer (SCLC) lines that do not produce ACTH. Twelve genes were expressed at more than five-fold higher levels in DMS-79 cells. Two transcription factors were the genes that exhibited the most remarkable over-expression: T-box 3 mRNA was detected at levels 19.37 +/- 3.78 times those observed in the SCLCs. Thyroid transcription factor (TTF-1, T/ebp, Nkx2.1) was expressed at 14.24 +/- 3.41-fold higher in DMS-79 cells. Seven genes were identified whose expression levels were at least five-fold lower in the ACTH-producing cell line. Variation in culture medium formulation did not significantly affect the gene expression profile of DMS-79 cells and expression data observed in microarray experiments were corroborated by northern blot analysis of RNA from the same cell lines. These experiments reveal new candidate genes that could be involved in the dysregulation of POMC gene expression manifested by ACTH-producing nonpituitary tumors.
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PMID:Gene expression phenotyping of an ACTH-producing small cell lung cancer line. 1514 32

N-Oct-3 is a neuronal transcription factor widely expressed in the developing mammalian central nervous system, and necessary to maintain neural cell differentiation. The key role of N-Oct-3 in the transcriptional regulation of a multiplicity of genes is primarily due to the structural plasticity of its so-called 'POU' (acronym of Pit, Oct, Unc) DNA-binding domain. We have recently reported about the unusual dual neuro-specific transcriptional regulation displayed by N-Oct-3 [Blaud,M., Vossen,C., Joseph,G., Alazard,R., Erard,M. and Nieto,L. (2004) J. Mol. Biol., 339, 1049-1058]. To elucidate the underlying molecular mechanisms, we have now made use of molecular modeling, DNA footprinting and electrophoretic mobility shift assay techniques. This combined approach has allowed us to uncover a novel mode of homodimerization adopted by the N-Oct-3 POU domain bound to the neuronal aromatic amino acids de-carboxylase and corticotropin-releasing hormone gene promoters and to demonstrate that this pattern is induced by a structural motif that we have termed 'NORE' (N-Oct-3 responsive element), comprising the 14 bp sequence element TNNRTAAATAATRN. In addition, we have been able to explain how the same structural motif can also induce the formation of a heterodimer in association with hepatocyte nuclear factor 3beta(/Forkhead box a2). Finally, we discuss the possible role of the NORE motif in relation to neuroendocrine lung tumor formation, and in particular the development of small cell lung cancer.
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PMID:Identification of the 'NORE' (N-Oct-3 responsive element), a novel structural motif and composite element. 1576 76

Endocrin paraneoplastic syndromes are characterized by an ectopic hormonal production. The ectopic adrenocorticotropic hormone (ACTH) secretion is often associated with small cell lung cancer. We report the case of 64-years-old man with persistent hypokalemia in Cushing's syndrome due to ectopic ACTH secretion. The patient was affected by small cell lung cancer and presented an hypothiroidism too. A proper chemotherapy resulted in remission of the hypokalemia, but the hypothiroidism was not influenced during our observation period.
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PMID:[Hypokalemia from ectopic ACTH secretion and hypothiroidism in patient affected by small cell lung cancer]. 1947 41

We present a case of a 60-year-old woman who initially presented with pneumonia and abdominal pain and was diagnosed with ectopic adrenocorticotropic hormone (ACTH) syndrome secondary to small cell lung cancer. We review published literature and summarize the typical challenges in the diagnosis and treatment of ectopic ACTH syndrome. Recent research has shed new light on the mechanism of ectopic ACTH production and provided a potential new target for treatment.
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PMID:Ectopic adrenocorticotropic hormone syndrome: a diagnostic challenge and review of the literature. 2124 Mar 27

Paraneoplastic Cushing's syndrome caused by ectopic adrenocorticotropin (ACTH) production has been reported. However, most cases of this syndrome are diagnosed before first-line chemotherapy or at the time of disease recurrence. Here, we present a 53-year-old man who gradually developed the symptoms of Cushing's syndrome during effective chemotherapy for small cell lung cancer. His symptoms were controlled using mitotane, but his primary cancer progressed and he died 5 months after the start of chemotherapy. This very rare case of Cushing's syndrome associated with small cell lung cancer during effective chemotherapy is presented here.
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PMID:Development of Cushing's syndrome during effective chemotherapy for small cell lung cancer. 2132 67

Small cell lung cancer (SCLC) with ectopic adrenocorticotropic hormone (ACTH) syndrome and resultant hypercortisolism carries a poor prognosis with a short median survival and high incidence of infective complications. The combination of etoposide with either carboplatin or cisplatin is the current standard chemotherapy used for the management of SCLC. Etoposide is metabolised by cytochrome P450 3A4. Ketoconazole is an imidazole derivative possessing antifungal properties and also causes inhibition of adrenal corticosteroid and androgen production. There is an additional increased risk of toxicity due to a potential interaction between etoposide and ketoconazole, which is a strong inhibitor of cytochrome P450 3A4, and theoretically can lead to greater myelosuppression. Metyrapone can be a safe alternative in such settings.
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PMID:Metyrapone: a management option for ectopic ACTH syndrome in small cell lung cancer treated with intravenous etoposide. 2268 64

Ectopic adrenocorticotropic hormone (ACTH) syndrome is caused most frequently by a bronchial carcinoid tumor or by small cell lung cancer. Medullary thyroid carcinoma (MTC) is a rare etiology of ectopic ACTH syndrome. We describe a case of Cushing syndrome due to ectopic ACTH production from MTC in a 48-year-old male. He was diagnosed with MTC 14 years ago and underwent total thyroidectomy, cervical lymph node dissection and a series of metastasectomies. MTC was confirmed by the pathological examination of the thyroid and metastatic mediastinal lymph node tissues. Two years after his last surgery, he developed Cushingoid features, such as moon face and central obesity, accompanied by uncontrolled hypertension and new-onset diabetes. The laboratory results were compatible with ectopic ACTH syndrome. A bilateral adrenalectomy improved the clinical and laboratory findings that were associated with Cushing syndrome. This is the first confirmed case of ectopic ACTH syndrome caused by MTC in Korea.
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PMID:Medullary thyroid carcinoma with ectopic adrenocorticotropic hormone syndrome. 2474 61

Small cell lung cancer (SCLC), which originated from neuroendocrine tissue, can develop into paraneoplastic endocrine syndromes, such as Cushing syndrome, because of an inappropriate secretion of ectopic adrenocorticotropic hormone (ACTH). This paraneoplastic syndrome is known to be a poor prognostic factor in SCLC. The reason for poor survival may be because of a higher risk of infection associated with hypercortisolemia. Therefore, early detection and appropriate treatment for this syndrome is necessary. But the diagnosis is challenging and the source of ACTH production can be difficult to identify. We report a 69-year-old male patient who had severe hypokalemia, metabolic alkalosis, and hypertension as manifestations of an ACTH-secreting small cell carcinoma of the lung. He was treated with ketoconazole and spironolactone to control the ACTH dependent Cushing syndrome. He survived for 15 months after chemotherapy, which is unusual considering the poor outcome of the ectopic ATH syndrome associated with SCLC.
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PMID:A Case of Ectopic Adrenocorticotropic Hormone Syndrome in Small Cell Lung Cancer. 2650 41


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