Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P04626 (erbB-2)
 5,251 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

90 primary breast carcinomas and 18 metastases were immunostained for c-erbB-2 protein and neuron specific enolase. 30 tumours were c-erbB-2 negative and NSE positive, 23 tumours were NSE negative and c-erbB-2 positive. 1 tumour expressed focal immunoreactivity for both markers. 54 of the 108 tumours (50%) did not express either marker. Hormone immunoreactivity was present in single cells and in small groups of cells in 18 of the 31 NSE positive tumours. Bombesin, neurotensin and prealbumin were present in 4 cases each, followed by beta-endorphin and VIP in 3 cases each, leu-enkephalin in 2 cases and gastrin, serotonin, substance P, glucagon and somatostatin in 1 case each. None of 10 NSE negative breast carcinomas were comprised of cells expressing immunoreactivity for hormones. By immunoelectron microscopic examination the c-erbB-2 protein was shown to be present on the cell membrane, on smooth areas, microvilli and in coated pits. Immunoreactivity was also expressed in vesicles in cytoplasm and along rough endoplasmic reticulum. The study shows that c-erbB-2 protein expression and neuroendocrine activity are present in different tumour cell populations. This supports the hypothesis that the presence of c-erbB-2 protein, indicating an elevated cellular tyrosine kinase activity with stimulation of growth, intracellular Ca++, and phosphatidylinositol derivates, means that the same cell does not need regulation of the same factors by stimulation of peptide hormone receptors. Thus the production of autocrine and paracrine factors is switched off.
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PMID:C-erbB-2 protein and neuroendocrine expression in breast carcinomas. 167 29

This study investigated the mechanisms by which TAGH solution (a mixture of triiodothyronine, amino acids, glucagon, and heparin) induces DNA synthesis in hepatocytes in the liver of intact rats, with particular reference to events at the epidermal growth factor (EGF) receptor. Both partial hepatectomy and infusion of TAGH stimulated DNA synthesis at 24 hours and both procedures resulted in a reduction of EGF receptors assessed in plasma membranes isolated from rat liver at this time. In cell cultures, while EGF strongly stimulated DNA synthesis and started EGF receptor down regulation, TAGH had only a minor effect (1.5 x basal) on DNA synthesis and did not interact with or down regulate the EGF receptor. Membrane phosphorylation studies, however, showed that TAGH induced phosphorylation of tyrosine residues in the EGF receptor. The in vivo action of TAGH seems to entail recruitment of similar changes in the EGF receptor to those that occur after partial hepatectomy.
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PMID:Down regulation of epidermal growth factor receptors in liver proliferation induced by a mixture of triiodothyronine, amino acids, glucagon, and heparin (TAGH). 824 50

The neuregulin (NRG)/epidermal growth factor (EGF) family of growth factors consists of several ligands that specifically activate four erbB receptor-tyrosine kinases, namely erbB-1 (EGF-R), erbB-2 (neu), erbB-3, and erbB-4. We have previously shown that islet morphogenesis is impaired and beta-cell differentiation delayed in mice lacking functional EGF-R [EGF-R (-/-)]. The present study aims to clarify which erbB ligands are important for islet development. Pancreatic expression of EGF, TGF-alpha, heparin-binding EGF, betacellulin (BTC), and NRG-4 was detected as early as embryonic d 13 (E13). Effects of these ligands were studied in E12.5 pancreatic explant cultures grown for 5 d ex vivo. None of the growth factors affected the ratio of endocrine to exocrine cells. However, significant effects within the endocrine cell populations were induced by EGF, BTC, and NRG-4. beta-Cell development was augmented by BTC, whereas the development of somatostatin-expressing delta-cells was stimulated by NRG-4. Both ligands decreased the numbers of glucagon-containing alpha-cells. The effect of BTC was abolished in the EGF-R (-/-) mice. A soluble erbB-4 binding fusion protein totally inhibited the effects of NRG-4 but not of BTC. Neutralization of endogenous NRG-4 activity in the model system effectively inhibited delta-cell development, indicating that this erbB4-ligand is an essential factor for delineation of the somatostatin-producing delta-cells. Our results suggest that ligands of the EGF-R/erbB-1 and erbB-4 receptors regulate the lineage determination of islet cells during pancreatic development. BTC, acting through EGF-R/erbB-1, is important for the differentiation of beta-cells. This could be applied in the targeted differentiation of stem cells into insulin-producing cells.
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PMID:ErbB signaling regulates lineage determination of developing pancreatic islet cells in embryonic organ culture. 1239 41

We previously provided evidence that glucagon-like peptide 1 (GLP-1) induces pancreatic beta-cell growth nonadditively with glucose in a phosphatidylinositol (PI) 3-kinase- and protein kinase C zeta-dependent manner. However, the exact mechanism by which the GLP-1 receptor (GLP-1R), a member of the G protein-coupled receptor (GPCR) superfamily, activates the PI 3-kinase signaling pathway to promote beta-cell growth remains unknown. We hypothesized that the GLP-1R could activate PI 3-kinase and promote beta-cell proliferation through transactivation of the epidermal growth factor (EGF) receptor (EGFR), an event possibly linked to GPCRs via activation of c-Src and the production of putative endogenous EGF-like ligands. Both the c-Src inhibitor PP1 and the EGFR-specific inhibitor AG1478 blocked GLP-1-induced [(3)H]thymidine incorporation in INS(832/13) cells as well as in isolated rat islets, while only AG1478 inhibited the proliferative action of betacellulin (BTC), an EGFR agonist. Both compounds also suppressed GLP-1-induced PI 3-kinase activation. A time-dependent increase in tyrosine phosphorylation of the EGFR in response to GLP-1 was observed in INS(832/13) cells. This transactivation of the EGFR was sensitive to both the pharmacological agents PP1 and AG1478. The action of GLP-1 and BTC on INS cell proliferation was found to be not additive. Overexpression of a dominant-negative EGFR in INS cells with a retroviral expression vector curtailed GLP-1-induced beta-cell proliferation. GLP-1 treatment of INS cells caused a decrease in cell surface-associated BTC, as shown by FACS analysis. Also, the metalloproteinase inhibitor GM6001 and an anti-BTC neutralizing antibody suppressed the GLP-1 proliferative effect. Finally, coculturing the prostatic cancer cell line LNCaP that lacks GLP-1 responsiveness with INS cells increased LNCaP cell proliferation in the presence of GLP-1, thus revealing that INS cells secrete a growth factor in response to GLP-1. GM6001 and an anti-BTC neutralizing antibody suppressed increased LNCaP cell proliferation in the presence of GLP-1 in the coculture experiments. The results are consistent with a model in which GLP-1 increases PI 3-kinase activity and enhances beta-cell proliferation via transactivation of the EGFR that would require the proteolytic processing of membrane-anchored BTC or other EGF-like ligands.
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PMID:Glucagon-like peptide 1 induces pancreatic beta-cell proliferation via transactivation of the epidermal growth factor receptor. 1250 2

Antagonism of voltage-dependent K+ (Kv) currents in pancreatic beta-cells may contribute to the ability of glucagon-like peptide-1 (GLP-1) to stimulate insulin secretion. The mechanism and signaling pathway regulating these currents in rat beta-cells were investigated using the GLP-1 receptor agonist exendin 4. Inhibition of Kv currents resulted from a 20-mV leftward shift in the voltage dependence of steady-state inactivation. Blocking cAMP or protein kinase A (PKA) signaling (Rp-cAMP and H-89, respectively) prevented the inhibition of currents by exendin 4. However, direct activation of this pathway alone by intracellular dialysis of cAMP or the PKA catalytic subunit (cPKA) could not inhibit currents, implicating a role for alternative signaling pathways. A number of phosphorylation sites associated with phosphatidylinositol 3 (PI3)-kinase activation were up-regulated in GLP-1-treated MIN6 insulinoma cells, and the PI3 kinase inhibitor wortmannin could prevent antagonism of beta-cell currents by exendin 4. Antagonists of Src family kinases (PP1) and the epidermal growth factor (EGF) receptor (AG1478) also prevented current inhibition by exendin 4, demonstrating a role for Src kinase-mediated trans-activation of the EGF tyrosine kinase receptor. Accordingly, the EGF receptor agonist betacellulin could replicate the effects of exendin 4 in the presence of elevated intracellular cAMP. Downstream, the PKCzeta pseudosubstrate inhibitor could prevent current inhibition by exendin 4. Therefore, antagonism of beta-cell Kv currents by GLP-1 receptor activation requires both cAMP/PKA and PI3 kinase/PKCzeta signaling via trans-activation of the EGF receptor. This represents a novel dual pathway for the control of Kv currents by G protein-coupled receptors.
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PMID:Antagonism of rat beta-cell voltage-dependent K+ currents by exendin 4 requires dual activation of the cAMP/protein kinase A and phosphatidylinositol 3-kinase signaling pathways. 1456 57