Identification of plasminogen activator inhibitor-2 as a gastrin-regulated gene: Role of Rho GTPase and menin.
OBJECTIVE
The gastric hormone gastrin regulates acid secretion, gene expression, and the functional development and cellular composition of the gastric mucosa. Using a gene array, we sought to identify major, novel, gastrin-regulated genes.


METHODS
A cancer gene array was probed with samples from the gastric cancer cell line AGS, expressing the gastrin-cholecystokinin(B) receptor and stimulated with gastrin. The expression of gastrin-regulated genes was further characterized by Western blots and enzyme-linked immunosorbent assay in tissue and blood of hypergastrinemic patients. Gene expression was studied using promoter-luciferase reporter constructs.


RESULTS
Plasminogen activator inhibitor 2 (PAI-2) was identified as a major, previously unknown target of gastrin in the gastric cancer cell line AGS. The relevance was confirmed by showing elevated tissue and plasma PAI-2 in hypergastrinemic patients (pernicious anemia and multiple endocrine neoplasia type 1). PAI-2 promoter-luciferase constructs showed that gastrin stimulated expression via pathways involving Galpha and Gbetagamma subunits, protein kinase C, RhoA, and the transcription factors CREB and AP1. The tumor suppressor menin inhibited transcription. In addition, gastrin stimulated expression in adjacent cells via a paracrine mechanism involving protein kinase C and RhoA but not CREB.


CONCLUSIONS
A gene array showed PAI-2 to be a novel gastrin-regulated gene, stimulated in part through CREB and AP-1 and inhibited by the tumor suppressor menin.
Varro
Andrea
A
Physiological Laboratory, University of Liverpool, Liverpool, England. avarro@liverpool.ac.uk
Hemers
Elaine
E
Archer
Debbie
D
Pagliocca
Adelina
A
Haigh
Chris
C
Ahmed
Suhail
S
Dimaline
Rod
R
Dockray
Graham J
GJ
D000368:Aged; D017362:Cyclic AMP Response Element-Binding Protein / Q000502:physiology; D005260:Female; D005753:Gastric Mucosa / Q000378:metabolism; D005755:Gastrins / Q000097:blood / Q000494:pharmacology / Q000502:physiology*; D005786:Gene Expression Regulation / Q000502:physiology*; D017930:Genes, Reporter; D006801:Humans; D008156:Luciferases / Q000235:genetics; D008297:Male; D008875:Middle Aged; D020928:Mitogen-Activated Protein Kinases / Q000502:physiology; D009363:Neoplasm Proteins / Q000502:physiology*; D020411:Oligonucleotide Array Sequence Analysis; D019899:Paracrine Communication; D017396:Plasminogen Activator Inhibitor 2 / Q000097:blood / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000502:physiology; D011493:Protein Kinase C / Q000502:physiology; D011518:Proto-Oncogene Proteins; D015398:Signal Transduction / Q000502:physiology; D018808:Transcription Factor AP-1 / Q000502:physiology; D014158:Transcription, Genetic / Q000502:physiology; D014407:Tumor Cells, Cultured; D020741:rho GTP-Binding Proteins / Q000502:physiology*
D017362:Cyclic AMP Response Element-Binding Protein; D005755:Gastrins; C105373:MEN1 protein, human; D009363:Neoplasm Proteins; D017396:Plasminogen Activator Inhibitor 2; D011518:Proto-Oncogene Proteins; D018808:Transcription Factor AP-1; D008156:Luciferases; D011493:Protein Kinase C; D020928:Mitogen-Activated Protein Kinases; D020741:rho GTP-Binding Proteins