Expression of human TFF3 in relation to growth of HT-29 cell subpopulations: involvement of PI3-K but not STAT6.
The trefoil factor family (TFF) peptides 1 and 2 (TFF1 and 2) are expressed in mucus cells of the stomach, whereas TFF3 is localized in goblet cells of the intestine. In the present study, we aimed to determine whether phosphatidylinositol 3-kinase (PI3-K) or signal transducer and activator of transcription protein 6 (STAT6) is involved in the expression of goblet cell specific markers. TFF3 expression was analyzed by RT-PCR, Northern blot, and radioimmunoassay (RIA) in relation to cell growth in subclones of HT-29 cells including the CL.16E and methotrexate (MTX) cell lines, which both exhibit a phenotype of mucus-secreting intestinal cells. A 30-fold increase in TFF3 mRNA levels and a 10-fold increase in TFF3-cell content were observed between the early proliferative and the late confluency states. The levels of MUC2 and MUC3 mRNA were also increased in the course of the differentiation process. A three to fourfold increase in PI3-K and Akt activities was observed in early post-confluent cells as compared with pre-confluent cells. Exposure of pre- and post-confluent cells to LY294002, a specific PI3-K inhibitor, for 1-4 days profoundly reduced TFF3 and MUC2 expression. A marked reduction in mucin granules content was also observed in LY-treated cells. Inhibition of the mitogen-activated protein (MAP) kinase kinase (MEK) with PD98059 did not modify the course of differentiation of the goblet cell lines. Moreover, stable transfection of HT-29 CL.16E cells with a dominant negative form of STAT6 had no effect on TFF3 induction. Together, these data indicate that PI3-K promotes the expression of TFF3 and MUC2 and that the PI3-K/Akt pathway may play a pivotal role in intestinal goblet cell differentiation.
Durual
Stéphane
S
INSERM U45, Faculté de Médecine Laennec 7, rue G.Paradin, 69372 Lyon cedex 08, France.
Blanchard
Carine
C
Estienne
Monique
M
Jacquier
Marie-France
MF
Cuber
Jean-Claude
JC
Perrot
Valérie
V
Laboisse
Christian
C
Cuber
Jean-Claude
JC
D002454:Cell Differentiation / Q000187:drug effects / Q000235:genetics; D002867:Chromones / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D005786:Gene Expression Regulation; D005799:Genes, Dominant; D020397:Goblet Cells / Q000166:cytology / Q000502:physiology; D019073:HT29 Cells; D006801:Humans; D007422:Intestines / Q000166:cytology*; D020930:MAP Kinase Kinase Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D008727:Methotrexate / Q000494:pharmacology; D009025:Morpholines / Q000494:pharmacology; D055262:Mucin-2; D055263:Mucin-3; D009077:Mucins / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D009124:Muscle Proteins / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D010455:Peptides; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D050800:STAT6 Transcription Factor; D015398:Signal Transduction; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D000071165:Trefoil Factor-3
D002867:Chromones; D004791:Enzyme Inhibitors; D005419:Flavonoids; D020930:MAP Kinase Kinase Kinases; D008727:Methotrexate; D009025:Morpholines; D055262:Mucin-2; D055263:Mucin-3; D009077:Mucins; D009124:Muscle Proteins; D010455:Peptides; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D050800:STAT6 Transcription Factor; D015534:Trans-Activators; D000071165:Trefoil Factor-3; C524625:MUC2 protein, human; C494101:STAT6 protein, human; C082495:TFF3 protein, human; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; C494918:AKT1 protein, human; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one