The effect of dexamethasone on expression of mitogen-induced cyclooxygenase-2 mRNA by amnion-derived (WISH) cells.
OBJECTIVE
It has been reported that prostaglandin E(2) (PGE(2)) is synthesized in the amnion and that this synthesis increases during labor. The purpose of this study was to clarify the mechanism for the expression of cyclooxygenase-2 (COX-2) mRNA and the PGE(2) synthesis of amnion-derived (WISH) cells.


METHODS
Cells were cultured and treated by 12-O-tetradecanoylphorbol-13-acetate (TPA) and dexamethasone (DEX). PGE(2) in the culture medium was measured by ELISA. Total RNA was extracted from the cells, and COX-2 mRNA expression was analyzed by Northern blot analysis.


RESULTS
During the time course of PGE(2) production in response to TPA stimulation, the PGE(2) production could not be detected until incubation had continued for 2h, but this production appeared to continue after 4h of incubation. PGE(2) production was significantly increased by TPA and suppressed by treatment with TPA and DEX. During the time course of COX-2 mRNA expression in response to treatment with TPA, the COX-2 mRNA band was detected after 1.5h. The strongest expression of COX-2 mRNA was observed at 2h incubation. After pre-treatment with TPA for 1h, the TPA-induced COX-2 mRNA was suppressed by treatment with DEX for 1 or 2h incubation in a dose-dependent manner.


CONCLUSIONS
These results suggest that COX-2 mRNA is induced by TPA which activate protein kinase C, and suppressed by DEX in WISH cells.
Kawano
Y
Y
Department of Obstetrics and Gynecology, Oita Medical University, Hasama, 879-5593, Oita, Japan.
Nakamura
S
S
Narahara
H
H
Miyakawa
I
I
D000650:Amnion / Q000201:enzymology* / Q000378:metabolism; D002461:Cell Line, Transformed; D017077:Culture Media, Conditioned; D051546:Cyclooxygenase 2; D003907:Dexamethasone / Q000494:pharmacology*; D015232:Dinoprostone / Q000096:biosynthesis; D004797:Enzyme-Linked Immunosorbent Assay; D004847:Epithelial Cells; D015870:Gene Expression / Q000187:drug effects*; D005938:Glucocorticoids / Q000494:pharmacology; D006801:Humans; D007527:Isoenzymes / Q000235:genetics*; D007700:Kinetics; D008565:Membrane Proteins; D008934:Mitogens / Q000494:pharmacology*; D011451:Prostaglandin-Endoperoxide Synthases / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D017077:Culture Media, Conditioned; D005938:Glucocorticoids; D007527:Isoenzymes; D008565:Membrane Proteins; D008934:Mitogens; D012333:RNA, Messenger; D003907:Dexamethasone; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D015232:Dinoprostone; D013755:Tetradecanoylphorbol Acetate