Differential expression of prostaglandin endoperoxide H synthase-2 and formation of activated beta-catenin-LEF-1 transcription complex in mouse colonic epithelial cells contrasting in Apc.
Mutations in Apc underlie the intestinal lesions in familial adenomatous polyposis and are found in >85% of sporadic colon cancers. They are frequently associated with overexpression of prostaglandin endoperoxide H synthase-2 (PGHS-2) in colonic adenomas. It has been suggested that Apc mutations are linked mechanistically to increased PGHS-2 expression by elevated nuclear accumulation of beta-catenin-Tcf-LEF transcription complex. In the present study, we show that PGHS-2 is differentially expressed in mouse colonic epithelial cells with distinct Apc status. Cells with a mutated Apc expressed markedly higher levels of PGHS-2 mRNA and protein and produced significantly more prostaglandin E2 than cells with normal Apc. Using electrophoretic mobility shift assays, we demonstrate that DNA-beta-catenin-LEF-1 complex formation is differentially induced in these two cell lines in an Apc-dependent manner. Our data indicate that the differential induction of beta-catenin-LEF-1 complex correlates closely with differential expression of PGHS-2. These findings support the hypothesis that the differential expression of PGHS-2 is mediated through the proposed beta-catenin/Tcf-LEF signaling pathway.
Mei
J M
JM
Laboratory of Nutritional and Molecular Regulation, Division of Basic Sciences, National Cancer Institute, Frederick, MD 21702, USA.
Hord
N G
NG
Winterstein
D F
DF
Donald
S P
SP
Phang
J M
JM
D000483:Alleles; D000818:Animals; D000952:Antigens, Polyomavirus Transforming / Q000235:genetics / Q000502:physiology; D001667:Binding, Competitive; D002460:Cell Line; D002461:Cell Line, Transformed; D002467:Cell Nucleus / Q000378:metabolism; D002472:Cell Transformation, Viral; D003106:Colon / Q000166:cytology* / Q000378:metabolism; D003433:Crosses, Genetic; D051546:Cyclooxygenase 2; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D004247:DNA / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D015232:Dinoprostone / Q000096:biosynthesis; D004790:Enzyme Induction; D004847:Epithelial Cells / Q000378:metabolism; D017491:Genes, APC; D007527:Isoenzymes / Q000096:biosynthesis* / Q000235:genetics; D051821:Lymphoid Enhancer-Binding Factor 1; D046911:Macromolecular Substances; D051379:Mice; D008817:Mice, Mutant Strains; D009841:Oligonucleotides / Q000378:metabolism; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D013539:Simian virus 40 / Q000235:genetics; D013696:Temperature; D015534:Trans-Activators; D014157:Transcription Factors / Q000378:metabolism*; D051176:beta Catenin
D000952:Antigens, Polyomavirus Transforming; C495267:CTNNB1 protein, mouse; D003598:Cytoskeletal Proteins; D004268:DNA-Binding Proteins; D007527:Isoenzymes; D051821:Lymphoid Enhancer-Binding Factor 1; D046911:Macromolecular Substances; D009841:Oligonucleotides; D012333:RNA, Messenger; D015534:Trans-Activators; D014157:Transcription Factors; D051176:beta Catenin; D004247:DNA; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases; D015232:Dinoprostone