Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01350 (gastrin)
 9,683 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Multiple endocrine neoplasia type 1 (MENI) is a promising model to understand endocrine and other tumors. Its most common endocrine expressions are tumors of parathyroids, entero-pancreatic neuro-endocrine tissue, and anterior pituitary. Recently, collagenomas and multiple angiofibromas of the dermis also have been recognized as very common. MEN1 can be characterized from different perspectives: (a) as a hormone (parathyroid hormone, gastrin, prolactin, etc.) excess syndrome with excellent therapeutic options; (b) as a syndrome with sometimes lethal outcomes from malignancy of entero-pancreatic neuro-endocrine or foregut carcinoid tissues; or (c) as a disorder than can give insight about cell regulation in the endocrine, the dermal, and perhaps other tissue systems. The MEN1 gene was identified recently by positional cloning, a comprehensive strategy of narrowing the candidate interval and evaluating all or most genes in that interval. This discovery has opened new approaches to basic and clinical issues. Germline MEN1 mutations have been identified in most MEN1 families. Germline MENI mutations were generally not found in families with isolated hyperparathyroidism or with isolated pituitary tumor. Thus, studies with the MENI gene helped establish that mutation of other gene(s) is likely causative of these two MEN1 phenocopies. MEN1 proved to be the gene most frequent L4 mutated in common-variety, nonhereditary parathyroid tumor, gastrinoma, insulinoma, or bronchial carcinoid. For example, in common-variety parathyroid tumors, mutation of several other genes (such as cyclin D1 and P53) has been found, but much less frequently than MEN1 mutation. The majority of germline and somatic MEN1 mutations predicted truncation of the encoded protein (menin). Such inactivating mutations strongly supported prior predictions that MEN1 is a tumor suppressor gene insofar as stepwise mutational inactivation of both copies can release a cell from normal growth suppression. Menin is principally a nuclear protein; menin interacts with junD. Future studies, such as discovery of menin's metabolic pathway, could lead to new opportunities in cell biology and in tumor therapy.
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PMID:The gene for multiple endocrine neoplasia type 1: recent findings. 1042 35

Enterochromaffin-like (ECL) cell hyperplasia and then irreversible neoplasia can be generated in the African rodent Mastomys natalensis using the H2 receptor blocker, loxtidine, for 8-16 wk. We used a GeneChip approach complemented by standard technologies to identify gene expression alterations in the gastric mucosa during gastrin-mediated ECL cell transformation. Gastric mucosa (mucosal scrapping) and ECL cell-enriched fractions were obtained from untreated Mastomys (controls) and from animals treated with loxtidine for 8 wk (hyperplasia). Tumor ECL cells were obtained by hand-dissection of gastric ECL cell nodules from animals treated with loxtidine for >16 wk and from a spontaneously developed ECL cell tumor. RNA was isolated, examined on rat U34A GeneChips, and comparison analysis was performed to identify altered gene expression. Alterations in gene expressions were examined further by immunohistochemistry, quantitative RT-PCR (Q-RT-PCR), sequencing and Western blot. GeneSpring analysis demonstrated alterations in few genes (<20) in hyperplastic and tumor mucosa. The histamine H1 receptor was consistently increased in proliferating mucosa. This gene change was confirmed by Q-RT-PCR. Other genes showing alterations included neural-(chromogranin A and somatostatin), cell-cycle-, and AP-1-associated genes. Immunostaining confirmed alterations in neural markers. Cluster analysis of ECL cell-enriched samples demonstrated that c-fos and junD were differently regulated. Q-RT-PCR and Western blot in prospectively collected gastric mucosal samples confirmed the differential expression of Fos and Jun. The negative regulators of AP-1, JunD, and Menin were decreased in tumor mucosa. A missense of unknown function was noted in the menin gene. Hypergastrinemia in an animal model of gastric carcinoids differentially altered the histamine type 1 receptor and gene expression and protein composition of AP-1. These results suggest that expression of this receptor and an altered composition of AP-1 with a loss of inhibition play a role in ECL cell transformation.
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PMID:Global expression analysis of ECL cells in Mastomys natalensis gastric mucosa identifies alterations in the AP-1 pathway induced by gastrin-mediated transformation. 1560 48

Somatostatin is a potent inhibitor of gastrin secretion and gene expression. Menin is a 67-kDa protein product of the multiple endocrine neoplasia type 1 (MEN1) gene that when mutated leads to duodenal gastrinomas, a tumor that overproduces the hormone gastrin. These observations suggest that menin might normally inhibit gastrin gene expression in its role as a tumor suppressor. Since somatostatin and ostensibly menin are both inhibitors of gastrin, we hypothesized that somatostatin signaling directly induces menin. Menin protein expression was significantly lower in somatostatin-null mice, which are hypergastrinemic. We found by immunohistochemistry that somatostatin receptor-positive cells (SSTR2A) express menin. Mice were treated with the somatostatin analog octreotide to determine whether activation of somatostatin signaling induced menin. We found that octreotide increased the number of menin-expressing cells, menin mRNA, and menin protein expression. Moreover, the induction by octreotide was greater in the duodenum than in the antrum. The increase in menin observed in vivo was recapitulated by treating AGS and STC cell lines with octreotide, demonstrating that the regulation was direct. The induction required suppression of protein kinase A (PKA) since forskolin treatment suppressed menin protein levels and octreotide inhibited PKA enzyme activity. Small-interfering RNA-mediated suppression of PKA levels raised basal levels of menin protein and prevented further induction by octreotide. Using AGS cells, we also showed for the first time that menin directly inhibits endogenous gastrin gene expression. In conclusion, somatostatin receptor activation induces menin expression by suppressing PKA activation.
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PMID:Somatostatin stimulates menin gene expression by inhibiting protein kinase A. 1875 9