Gastrin regulates the heparin-binding epidermal-like growth factor promoter via a PKC/EGFR-dependent mechanism

2004 ◽  
Vol 286 (6) ◽  
pp. G992-G999 ◽  
Author(s):  
Natalie F. Sinclair ◽  
Wandong Ai ◽  
Raktima Raychowdhury ◽  
Meixia Bi ◽  
Timothy C. Wang ◽  
...  
Keyword(s):  
Growth Factor ◽  
Egf Receptor ◽  
Gastric Cancer Cell Line ◽  
Cancer Cell Line ◽  
Luciferase Reporter ◽  
Human Gastric Cancer ◽  
Heparin Binding ◽  
Cis Acting ◽  
Signal Transduction Inhibitors ◽  
Egf Family

Gastrin is a known growth/differentiation factor for the gastric mucosa. Its effects are likely mediated by the induction of heparin-binding epidermal-like growth factor (HB-EGF), a member of the EGF family of growth factors that is expressed by gastric parietal cells. In this study, we investigated the regulation of the HB-EGF promoter by gastrin in a human gastric cancer cell line. Serial human HB-EGF promoter-luciferase reporter deletion constructs and heterologous promoter constructs were transfected into AGS-E cells and stimulated with gastrin (10−7M) with or without various signal transduction inhibitors. EMSA were also performed. Gastrin stimulation resulted in a fivefold increase in HB-EGF-luciferase activity. The cis-acting element mediating gastrin responsiveness was mapped to the −69 to −58 region of the HB-EGF promoter. Gastrin stimulation was PKC dependent and at least partially mediated by activation of the EGF receptor.

scholarly journals Gastrin regulates the TFF2 promoter through gastrin-responsive cis-acting elements and multiple signaling pathways

2007 ◽  
Vol 292 (6) ◽  
pp. G1726-G1737 ◽  
Author(s):  
Shuiping Tu ◽  
Alfred L. Chi ◽  
SeonHee Lim ◽  
Guanglin Cui ◽  
Zina Dubeykovskaya ◽  
...  
Keyword(s):  
Dna Binding ◽  
Promoter Activity ◽  
Growth Factor Receptor ◽  
Gastric Cancer Cell Line ◽  
Cancer Cell Line ◽  
Gastric Fundus ◽  
Luciferase Reporter ◽  
Dependent Manner ◽  
Mobility Shift ◽  
Cis Acting

Trefoil family factor 2 (TFF2) is expressed in gastrointestinal epithelial cells where it serves to maintain mucosal integrity and promote epithelial repair. The peptide hormone, gastrin, stimulates acid secretion but also induces proliferation of the acid-secreting mucosa. Because the relationship between these peptides of overlapping function is not understood, we chose to investigate the regulatory effect of gastrin on TFF2 expression. The expression of mRNA and protein of TFF2 was determined by RT-PCR and immunohistochemical staining, respectively. A series of truncated and mutant murine TFF2 promoter constructs was generated. Promoter activity was assessed using dual luciferase reporter assays. Gastrin-responsive DNA-binding sites in the TFF2 promoter were evaluated by electrophoretic mobility shift assay. Gastrin significantly increased the level of endogenous mRNA of TFF2 in the gastrin receptor-expressing AGS-E gastric cancer cell line in a time- and dose-dependent manner. TFF2 protein expression in the gastric fundus was elevated in hypergastrinemic (INS-GAS) transgenic mice and reduced in gastrin-deficient mice. Gastrin treatment increased TFF2 promoter activity through cis-acting regions, containing CCAATA- and GC-rich enhancers. Pretreatment with Y-F476, a gastrin/CCKB receptor antagonist, abolished gastrin-dependent promoter activity. Inhibitors of protein kinase C (PKC), mitogen/extracellular signal-regulated kinase (MEK1), and phosphatidylinositol 3-kinase (PI 3-kinase) reduced gastrin-dependent TFF2 promoter activity, whereas an epithelial growth factor receptor (EGFR) inhibitor had no effect. We found that gastrin regulates TFF2 transcription through a GC-rich DNA-binding site and a PKC-, MEK1- and PI 3-kinase-dependent but EGFR-independent pathway. Regulation of TFF2 by gastrin may play a role in the maintenance and repair of the gastrointestinal mucosa.

Heparin-binding EGF-like growth factor gene is induced in the mouse uterus temporally by the blastocyst solely at the site of its apposition: a possible ligand for interaction with blastocyst EGF-receptor in implantation

Development ◽  
1994 ◽  
Vol 120 (5) ◽  
pp. 1071-1083 ◽  
Author(s):  
S.K. Das ◽  
X.N. Wang ◽  
B.C. Paria ◽  
D. Damm ◽  
J.A. Abraham ◽  
...  
Keyword(s):  
Growth Factor ◽  
Egf Receptor ◽  
Heparan Sulphate ◽  
Luminal Epithelium ◽  
Heparin Binding ◽  
Mouse Uterus ◽  
Growth Factor Gene ◽  
Heparan Sulphate Proteoglycans ◽  
Egf Family

Heparin-binding EGF-like growth factor (HB-EGF) is a newly discovered member of the EGF family of growth factors. HB-EGF can bind to two loci on cell surfaces, heparan sulphate proteoglycans and EGF-receptor (EGF-R), and either one or both of these interactions could play a role in cell-cell interactions. In the rodent, increased endometrial vascular permeability at the site of blastocyst apposition is considered to be an earliest discernible prerequisite event in the process of implantation and this event coincides with the initial attachment reaction between the blastocyst trophectoderm and uterine luminal epithelium. This investigation demonstrates that the HB-EGF gene is expressed in the mouse uterine luminal epithelium surrounding the blastocyst 6–7 hours before the attachment reaction that occurs at 2200–2300 hours on day 4 of pregnancy. It was further demonstrated that this gene is not expressed in the luminal epithelium at the site of the blastocyst apposition during the progesterone-maintained delayed implantation, but is readily induced in the luminal epithelium surrounding an activated blastocyst after termination of the delay by an estrogen injection. In vitro studies showed that HB-EGF induced blastocyst EGF-R autophosphorylation, and promoted blastocyst growth, zona-hatching and trophoblast outgrowth. These results suggest possible interactions between the uterine HB-EGF and blastocyst EGF-R very early in the process of implantation, earlier than any other embryo-uterine interactions defined to date at the molecular level.

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