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)

We applied Southwestern and Western blotting and gel retardation techniques to investigate the changes that occur in the cyclic adenosine monophosphate (cAMP)-responsive element (CRE) binding (CREB) proteins in rapidly growing, chemically induced 5123tc and 5123D Morris hepatomas. Using the CRE sequences from the c-fos, E2A, and somatostatin gene promoters, we identified in the nuclear proteins from normal unstimulated or proliferating rat liver cells six different protein factors of Mr 34,000, 36,000, 40,000, 47,000, 56,000, and 72,000 capable of binding to the element. The Mr 47,000 protein had the highest specificity for the core CRE, suggesting its importance in cAMP-mediated gene expression. We could not find the Mr 47,000 CREB protein in the 5123tc and 5123D hepatomas. Our efforts to detect this protein in the tumors by (a) using the CRE sequence from different gene promoters, (b) altering the protocol for extracting nuclear proteins, or (c) attempting to restore its DNA-binding property by phosphorylation [with endogenous protein kinase(s), a catalytic subunit of cAMP-dependent protein kinase, and protein kinase C/dephosphorylation (with alkaline phosphatase)] were unsuccessful. The loss of tje Mr 47,000 CREB protein from solid tumors of the Morris hepatoma is likely to be related to the neoplastic properties of the tumor cell rather than to cell growth because the level of this protein remained unchanged during a 6-day period of liver regeneration. The nuclear extract from the Morris hepatoma that did not have the Mr 47,000 CRE-binding factor contained proteins immunologically related to the CREB, c-Jun, and c-Fos proteins. We conclude that the Mr 47,000 factor represents a distinct member of the CRE-binding protein family and that its absence from the hepatomas may lead to aberrant expression of cAMP-inducible genes.
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PMID:Changes in cyclic adenosine monophosphate-responsive element binding proteins in rat hepatomas. 182 83

Activation of neurons in the inferior mesenteric ganglion (IMG) was assessed using c-fos, JunB, and c-Jun expression in the guinea pig IMG and colonic myenteric plexus during mechanosensory stimulation and acute colitis in normal and capsaicin-treated animals. Intracolonic saline or 2% acetic acid was administered, and mechanosensory stimulation was performed by passage of a small (0.5 cm) balloon either 4 or 24 hr later. Lower doses of capsaicin or vehicle were used to activate primary afferent fibers during balloon passage. c-Jun did not respond to any of the stimuli in the study. c-fos and JunB were absent from the IMG and myenteric plexus of untreated and saline-treated animals. Acetic acid induced acute colitis by 4 hr, which persisted for 24 hr, but c-fos was found only in enteric glia in the myenteric plexus and was absent from the IMG. Balloon passage induced c-fos and JunB in only a small subset of IMG neurons and no myenteric neurons. However, balloon passage induced c-fos and JunB in IMG neurons (notably those containing somatostatin) and the myenteric plexus of acetic acid-treated animals. After capsaicin treatment, c-fos and JunB induction by balloon passage was inhibited in the IMG, but there was enhanced c-fos expression in the myenteric plexus. c-fos and JunB induction by balloon stimulation was also mimicked by acute activation of capsaicin-sensitive nerves. These data suggest that colitis enhances reflex activity of the IMG by a mechanism that involves activation of both primary afferent fibers and the myenteric plexus.
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PMID:Immediate-early gene expression in the inferior mesenteric ganglion and colonic myenteric plexus of the guinea pig. 1008 87

The proto-oncogene c-jun is involved in cellular proliferation by interfering with signals that lead to cellular differentiation. Moreover the induction of metalloproteinase gene appears to utilise the c-jun oncogene as intracellular messenger. The aims of this study were to evaluate a) the expression of c-jun oncogene in pancreatic cancer b) its relation with tumor histological features. Surgical specimens of pancreatic cancer were collected from 22 patients radically operated upon, and from 11 submitted to palliation. As a control group, 5 specimens of normal pancreas and 5 specimens of chronic pancreatitis were studied. C-jun staining was graded as follows: (-) positive cells < 10%, (+) from 10 to 30%, (+2), from 30 to 60%, (+3) from 60 to 90%. Glucagon and somatostatin staining was graded counting the positive cells of total numer of Langherans islet cells counted. c-Jun expression (low: < 30% and high: > 30%) was related to stage, architectural and cytological grading, vascular, lymph nodal, perineural invasion. Normal pancreas and chronic pancreatitis tissues appear to express the c-jun protein in less than 10% of ductal cells. The percentage of tumor cells stained for c-jun is increased as compared to the control group in 28/33 cases: in 13 (46%) it ranges from 10 to 30%; in 10 (36%) from 30 to 60% and in 5 (18%) from 60 to 90%. The frequency of high or low c-jun expression is not different in relation to the histological features of tumor. Moreover, c-jun protein is present in 40% of cells of Langherans islets in normal pancreas, chronic pancreatitis and pancreatic cancer. The Langherans islet cells stained for c-jun exhibit also a positivity for glucagon. In conclusion; a) in pancreatic cancer, the expression of c-jun is increased in tumour cells in majority of cases as compared to the control group, b) a c-jun positivity is also found in alpha cells with a pattern not different from control group, but the relation between the alpha cells and c-jun production is unknown, c) c-jun expression does not vary in relation to histological findings.
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PMID:The expression of proto-oncogene c-jun in human pancreatic cancer. 1021 7

The purpose of this study was to characterize changes in gene expression in the brain of a seasonal hibernator, the golden-mantled ground squirrel, Spermophilus lateralis, during the hibernation season. Very little information is available on molecular changes that correlate with hibernation state, and what has been done focused mainly on seasonal changes in peripheral tissues. We produced over 4000 reverse transcription-PCR products from euthermic and hibernating brain and compared them using differential display. Twenty-nine of the most promising were examined by Northern analysis. Although some small differences were observed across hibernation states, none of the 29 had significant changes. However, a more direct approach, investigating expression of putative hibernation-responsive genes by Northern analysis, revealed an increase in expression of transcription factors c-fos, junB, and c-Jun, but not junD, commencing during late torpor and peaking during the arousal phase of individual hibernation bouts. In contrast, prostaglandin D2 synthase declined during late torpor and arousal but returned to a high level on return to euthermia. Other genes that have putative roles in mammalian sleep or specific brain functions, including somatostatin, enkephalin, growth-associated protein 43, glutamate acid decarboxylases 65/67, histidine decarboxylase, and a sleep-related transcript SD464 did not change significantly during individual hibernation bouts. We also observed no decline in total RNA or total mRNA during torpor; such a decline had been previously hypothesized. Therefore, it appears that the dramatic changes in body temperature and other physiological variables that accompany hibernation involve only modest reprogramming of gene expression or steady-state mRNA levels.
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PMID:Gene expression in the brain across the hibernation cycle. 1023 10

The transcription factor CHOP (C/EBP homologous protein 10) is a bZIP protein induced by a variety of stimuli that evoke cellular stress responses and has been shown to arrest cell growth and to promote programmed cell death. CHOP cannot form homodimers but forms stable heterodimers with the C/EBP family of activating transcription factors. Although initially characterized as a dominant negative inhibitor of C/EBPs in the activation of gene transcription, CHOP-C/EBP can activate certain target genes. Here we show that CHOP interacts with members of the immediate-early response, growth-promoting AP-1 transcription factor family, JunD, c-Jun, and c-Fos, to activate promoter elements in the somatostatin, JunD, and collagenase genes. The leucine zipper dimerization domain is required for interactions with AP-1 proteins and transactivation of transcription. Analyses by electrophoretic mobility shift assays and by an in vivo mammalian two-hybrid system for protein-protein interactions indicate that CHOP interacts with AP-1 proteins inside cells and suggest that it is recruited to the AP-1 complex by a tethering mechanism rather than by direct binding of DNA. Thus, CHOP not only is a negative or a positive regulator of C/EBP target genes but also, when tethered to AP-1 factors, can activate AP-1 target genes. These findings establish the existence of a new mechanism by which CHOP regulates gene expression when cells are exposed to cellular stress.
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PMID:CHOP enhancement of gene transcription by interactions with Jun/Fos AP-1 complex proteins. 1052 47

The sst2 somatostatin receptor mediates the inhibitory effects of somatostatin on secretive and proliferative processes. We previously showed that sst2 is one of the major subtypes expressed in the rat pituitary, and its messenger RNA level is up-regulated by chronic treatment with estrogen. To investigate the molecular mechanisms regulating sst2 gene expression, we cloned the upstream region (9.5 kb) from the translation initiation codon of the rat sst2 gene. It contained a single intron (5.0 kb) at the 5'-untranslated region, lacked TATA and CCAAT boxes, and had multiple transcriptional start sites. Transient transfection analysis with deleted mutants of a luciferase reporter construct showed that the promoter activity was regulated negatively and positively in the distal and proximal promoter regions, respectively. The promoter activity of each construct was more efficient in GH(3) pituitary cells than in nonpituitary cells. The construct (-77/+172/luc) containing a cAMP response element (CRE; -54/-47) provided maximum promoter activity, but a further 5'-deleted construct dramatically reduced the activity. Competitive gel shift and supershift assays indicated that Sp2 and Sp3 were bound to an Sp1 site (-40/-31), and activating transcription factor-2 and c-Jun were bound to a CRE site. Both Sp1 and CRE sites were essential for the full promoter activity. Overexpression of the pituitary homeoprotein Pitx1 activated the promoter activity of the -4066/+172/luc construct, and mapping analysis indicated the existence of two Pitx1 response sites, including the CRE site. Estrogen also increased the promoter activity of -77/+172/luc in GH(3) cells or in HeLa cells overexpressing both the estrogen receptor and c-Jun. These studies demonstrated the nature of the rat sst2 gene and the functional importance of both Sp1 and CRE sites in regulating sst2 gene expression and suggest that the CRE site mediates, at least partly, the promoter activity activated by Pitx1 or estrogen.
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PMID:Characterization of 5'-flanking region of rat somatostatin receptor sst2 gene: transcriptional regulatory elements and activation by Pitx1 and estrogen. 1125 Sep 22

We previously demonstrated the presence of an enhancer that is located between nucleotides - 2264 and - 2495 in the 5' flanking region of the rat sodium/iodide symporter (NIS) gene (Ohno et al., 1999). When attached to NIS or heterologous promoters, this 232 bp fragment, which we call NUE, is able to stimulate transcription in a thyroid-specific and cAMP-dependent manner. A paired-domain transcription factor Pax8 binds to this enhancer and can stimulate the transcription in non-thyroid cells that do not normally support the NUE activities. Cotransfection of PKA, a downstream effector of cAMP, further potentiates the Pax8-mediated transactivation. However, this transcriptional machinery containing pax8 seems to require contributions from the neighboring cis-acting element that is similar to CRE/AP-1 consensus sequences. Modification of this putative CRE/AP-1 site not only represses the NUE transcriptional activities by 90% in FRTL-5 cells, but also nullifies the synergistic effect of PKA on pax8-mediated transactivation in HeLa cells. In this report, we have further characterized the putative CRE/AP-1 site within the NIS upstream enhancer using gel mobility shift assay. An oligonucleotide probe with NIS CRE/AP-1 sequence produced complex binding patterns in both FRTL-5 and HeLa cell, reflecting the presence of diverse classes of binding factors. When compared with CRE or AP-1 elements in other genes, the mobility shift pattern of NIS CRE/AP-1 was similar to those of collagenase TRE, c-Jun TRE, and somatostatin CRE, but the relative intensities of the binding complexes were quite different. This observation raises a possibility that the NIS CRE/AP-site is regulated by a novel mechanism.
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PMID:Characterization of the upstream enhancer of the rat sodium/iodide symporter gene. 1157 34

TT-232 is a somatostatin analogue containing a five-residue ring structure. The present report describes TT-232-induced signalling events in A431 cells, where a 4-h preincubation with the peptide irreversibly induced a cell death program, which involves DNA-laddering and the appearance of shrunken nuclei, but is unrelated to somatostatin signalling. Early intracellular signals of TT-232 include a transient two-fold activation of the extracellular signal-regulated kinase (ERK2) and a strong and sustained activation of the stress-activated protein kinases c-Jun NH(2)-terminal kinase (JNK)/SAPK and p38MAPK. Blocking the signalling to ERK or p38MAPK activation had no effect on the TT-232-induced cell killing. At the commitment time for inducing cell death, TT-232 decreased EGFR-tyrosine phosphorylation and prevented epidermial growth factor (EGF)-induced events like cRaf-1 and ERK2 activation. Signalling to ERK activation by FCS, phorbol 12-myristate 13-acetate (PMA) and platelet-derived growth factor (PDGF) was similarly blocked. Our data suggest that TT-232 triggers an apoptotic type of cell death, concomitant with a strong activation of JNK and a blockade of cellular ERK2 activation pathways.
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PMID:The somatostatin analogue TT-232 induces apoptosis in A431 cells: sustained activation of stress-activated kinases and inhibition of signalling to extracellular signal-regulated kinases. 1160 82

Transcriptional profiling (TP) offers a powerful approach to identify genes activated during memory formation and, by inference, the molecular pathways involved. Trace eyeblink conditioning is well suited for the study of regional gene expression because it requires the hippocampus, whereas the highly parallel task, delay conditioning, does not. First, we determined when gene expression was most regulated during trace conditioning. Rats were exposed to 200 trials per day of paired and unpaired stimuli each day for 4 days. Changes in gene expression were most apparent 24 h after exposure to 200 trials. Therefore, we profiled gene expression in the hippocampus 24 h after 200 trials of trace eyeblink conditioning, on multiple arrays using additional animals. Of 1,186 genes on the filter array, seven genes met the statistical criteria and were also validated by real-time polymerase chain reaction. These genes were growth hormone (GH), c-kit receptor tyrosine kinase (c-kit), glutamate receptor, metabotropic 5 (mGluR5), nerve growth factor-beta (NGF-beta), Jun oncogene (c-Jun), transmembrane receptor Unc5H1 (UNC5H1), and transmembrane receptor Unc5H2 (UNC5H2). All these genes, except for GH, were downregulated in response to trace conditioning. GH was upregulated; therefore, we also validated the downregulation of the GH inhibitor, somatostatin (SST), even though it just failed to meet criteria on the arrays. By during situ hybridization, GH was expressed throughout the cell layers of the hippocampus in response to trace conditioning. None of the genes regulated in trace eyeblink conditioning were similarly affected by delay conditioning, a task that does not require the hippocampus. These findings demonstrate that transcriptional profiling can exhibit a repertoire of genes sensitive to the formation of hippocampal-dependent associative memories.
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PMID:Transcriptional profiling reveals regulated genes in the hippocampus during memory formation. 1254 33

Somatostatin is a multifunctional hormone that modulates cell proliferation, differentiation and apoptosis. Mechanisms for somatostatin-induced apoptosis are at present mostly unsolved. Therefore, we investigated whether somatostatin receptor subtype 2 (sst2) induces apoptosis in the nontransformed murine fibroblastic NIH3T3 cells. Somatostatin receptor subtype 2 expression induced an executioner caspase-mediated apoptosis through a tyrosine phosphatase SHP-1 (Src homology domain phosphatase-1)-dependent stimulation of nuclear factor kappa B (NF-kappaB) activity and subsequent inhibition of the mitogen-activated protein kinase JNK. Tumor necrosis factor alpha (TNFalpha) stimulated both NF-kappaB and c-Jun NH2-terminal kinase (JNK) activities, which had opposite action on cell survival. Importantly, sst2 sensitized NIH3T3 cells to TNFalpha-induced apoptosis by (1) upregulating TNFalpha receptor protein expression, and sensitizing to TNFalpha-induced caspase-8 activation; (2) enhancing TNFalpha-mediated activation of NF-kappaB, resulting in JNK inhibition and subsequent executioner caspase activation and cell death. We have here unraveled a novel signaling mechanism for a G protein-coupled receptor, which directly triggers apoptosis and crosstalks with a death receptor to enhance death ligand-induced apoptosis.
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PMID:Novel synergistic mechanism for sst2 somatostatin and TNFalpha receptors to induce apoptosis: crosstalk between NF-kappaB and JNK pathways. 1664 35


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