Gastrin regulates the TFF2 promoter through gastrin-responsive cis-acting elements and multiple signaling pathways.
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/CCK(B) 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.
Tu
Shuiping
S
Division of Digestive and Liver Diseases, Dept. of Medicine, College of Physicians and Surgeons, Columbia Univ., 1130 St. Nicholas Ave., Rm. 925, 9th Fl., New York, NY 10032, USA.
Chi
Alfred L
AL
Lim
Seonhee
S
Cui
Guanglin
G
Dubeykovskaya
Zina
Z
Ai
Wandong
W
Fleming
John V
JV
Takaishi
Shigeo
S
Wang
Timothy C
TC
D000818:Animals; D001483:Base Sequence; D001570:Benzodiazepinones / Q000494:pharmacology; D045744:Cell Line, Tumor; D002867:Chromones / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005419:Flavonoids / Q000494:pharmacology; D020862:GC Rich Sequence; D005753:Gastric Mucosa / Q000378:metabolism*; D005755:Gastrins / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D017930:Genes, Reporter; D006801:Humans; D008156:Luciferases; D048369:MAP Kinase Kinase 1 / Q000037:antagonists & inhibitors / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D009025:Morpholines / Q000494:pharmacology; D009077:Mucins / Q000235:genetics / Q000378:metabolism*; D009124:Muscle Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D010455:Peptides / Q000235:genetics / Q000378:metabolism*; D010671:Phenylurea Compounds / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011401:Promoter Regions, Genetic / Q000187:drug effects; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D043887:Receptor, Cholecystokinin B / Q000187:drug effects / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D019311:Staurosporine / Q000494:pharmacology; D013270:Stomach / Q000187:drug effects / Q000473:pathology; D013997:Time Factors; D014158:Transcription, Genetic / Q000187:drug effects; D014162:Transfection; D000071164:Trefoil Factor-2
D001570:Benzodiazepinones; D002867:Chromones; D005419:Flavonoids; D005755:Gastrins; D008156:Luciferases; D048369:MAP Kinase Kinase 1; D009025:Morpholines; D009077:Mucins; D009124:Muscle Proteins; D010455:Peptides; D010671:Phenylurea Compounds; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011493:Protein Kinase C; D047428:Protein Kinase Inhibitors; D012333:RNA, Messenger; D043887:Receptor, Cholecystokinin B; D019311:Staurosporine; D000071164:Trefoil Factor-2; C000604007:TFF2 protein, human; C481546:TFF2 protein, mouse; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; C104428:YF 476; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one