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Expression of cyclooxygenase 2 by prostaglandin E(2) in human endometrial adenocarcinoma cell line HEC-1B
I Munir1, K Fukunaga, H Kanasaki
1Department of Pharmacology, Kumamoto University Schoolof Medicine, Kumamoto 860-0811, Japan.
Abstract:
The regulation of expression of cyclooxygenase 2 (COX-2) was investigated by treatment with PGE(2) in human endometrial adenocarcinoma cell line HEC-1B. One microM PGE(2) could stimulate the expression of COX-2 approximately twofold in this cell line. The same concentration of PGE(2) also stimulated activation of mitogen-activated protein kinase (MAP kinase) and protein kinase B (PKB). PGE(2)-induced MAP kinase activation was sensitive to a MAP kinase kinase (MEK) inhibitor, PD098059, and a protein kinase A inhibitor, H-89. PD098059 and H-89 also partially inhibited the expression of COX-2 stimulated by PGE(2). PGE(2) could stimulate the activation of PKB, which was sensitive to phosphatidylinositol-3-OH kinase (PI3K) inhibitor, wortmannin. Whereas wortmannin alone partially inhibited the expression of COX-2, a combination of wortmannin and PD098059 totally inhibited PGE(2)-mediated COX-2 expression. These results suggest that MAP kinase and PI3K pathways are stimulated with PGE(2), and that both of these pathways are involved in the expression of COX-2. In addition, they also suggest that protein kinase A remains upstream of PGE(2)-induced activation of MAP kinase in HEC-1B cells.
Insights
Prostaglandin E2 (PGE2) stimulates cyclooxygenase 2 (COX-2) expression in endometrial cancer cells. Both MAP kinase and PI3K pathways are crucial for this PGE2-induced COX-2 expression.
Area of Science:
- Molecular Biology
- Cell Biology
- Cancer Research
Background:
- Cyclooxygenase 2 (COX-2) plays a significant role in endometrial adenocarcinoma.
- Prostaglandin E2 (PGE2) is implicated in the regulation of COX-2 expression.
Purpose of the Study:
- To investigate the signaling pathways involved in PGE2-mediated COX-2 expression in the HEC-1B cell line.
- To elucidate the roles of MAP kinase and PI3K pathways in COX-2 regulation.
Main Methods:
- Treatment of HEC-1B cells with PGE2.
- Inhibition of MAP kinase (MEK inhibitor PD098059) and PI3K (wortmannin) pathways.
- Assessment of COX-2 expression levels.
- Analysis of MAP kinase and protein kinase B (PKB) activation.
Main Results:
- PGE2 treatment stimulated COX-2 expression approximately twofold in HEC-1B cells.
- PGE2 also activated MAP kinase and PKB.
- Inhibitors of MEK (PD098059) and PI3K (wortmannin) partially inhibited PGE2-induced COX-2 expression.
- Combined inhibition of MEK and PI3K completely blocked PGE2-mediated COX-2 expression.
- Protein kinase A (PKA) was found to be upstream of PGE2-induced MAP kinase activation.
Conclusions:
- Both MAP kinase and PI3K signaling pathways are activated by PGE2 and are involved in regulating COX-2 expression in HEC-1B cells.
- PKA acts upstream of PGE2-induced MAP kinase activation in this cellular model.