Inhibition of cyclooxygenase-1 and -2 expression by targeting the endothelin a receptor in human ovarian carcinoma cells.
OBJECTIVE
New therapies against cancer are based on targeting cyclooxygenase (COX)-2. Activation of the endothelin A receptor (ET(A)R) by endothelin (ET)-1 is biologically relevant in several malignancies, including ovarian carcinoma. In this tumor, the ET-1/ET(A)R autocrine pathway promotes mitogenesis, apoptosis protection, invasion, and neoangiogenesis. Because COX-1 and COX-2 are involved in ovarian carcinoma progression, we investigated whether ET-1 induced COX-1 and COX-2 expression through the ET(A)R at the mRNA and protein level in HEY and OVCA 433 ovarian carcinoma cell lines by Northern blot, reverse transcription-PCR, Western blot, and immunohistochemistry; we also investigated the activity of the COX-2 promoter by luciferase assay and the release of prostaglandin (PG) E(2) by ELISA.


RESULTS
ET-1 significantly increases the expression of COX-1 and COX-2, COX-2 promoter activity, and PGE(2) production. These effects depend on ET(A)R activation and involve multiple mitogen-activated protein kinase (MAPK) signaling pathways, including p42/44 MAPK, p38 MAPK, and transactivation of the epidermal growth factor receptor. COX-2 inhibitors and, in part, COX-1 inhibitor blocked ET-1-induced PGE(2) and vascular endothelial growth factor release, indicating that both enzymes participate in PGE(2) production to a different extent. Moreover, inhibition of human ovarian tumor growth in nude mice after treatment with the potent ET(A)R-selective antagonist ABT-627 is associated with reduced COX-2 and vascular endothelial growth factor expression.


CONCLUSIONS
These results indicate that impairing COX-1 and COX-2 and their downstream effect by targeting ET(A)R can be therapeutically advantageous in ovarian carcinoma treatment. Pharmacological blockade of the ET(A)R is an attractive strategy to control COX-2 induction, which has been associated with ovarian carcinoma progression and chemoresistance.
Laboratories of Molecular Pathology and Ultrastructure and Immunology, Regina Elena Cancer Institute, Rome, Italy.
Francesca
F
Spinella
Laura
L
Rosanò
Valeriana
V
Di Castro
Maria Rita
MR
Nicotra
Pier Giorgio
PG
Natali
Anna
A
Bagnato
D000818:Animals; D000077868:Atrasentan; D015152:Blotting, Northern; D015153:Blotting, Western; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D015232:Dinoprostone / Q000096:biosynthesis; D065130:Endothelin A Receptor Antagonists; D019332:Endothelin-1 / Q000494:pharmacology; D005260:Female; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D007213:Indomethacin / Q000494:pharmacology; D007527:Isoenzymes / Q000235:genetics* / Q000378:metabolism; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000187:drug effects; D008565:Membrane Proteins; D051379:Mice; D008819:Mice, Nude; D009578:Nitrobenzenes / Q000494:pharmacology; D010051:Ovarian Neoplasms / Q000201:enzymology / Q000473:pathology / Q000517:prevention & control; D011401:Promoter Regions, Genetic / Q000235:genetics; D011451:Prostaglandin-Endoperoxide Synthases / Q000235:genetics* / Q000378:metabolism; D011720:Pyrazoles / Q000494:pharmacology; D011759:Pyrrolidines / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D044022:Receptor, Endothelin A / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013449:Sulfonamides / Q000494:pharmacology; D014162:Transfection; D015854:Up-Regulation / Q000187:drug effects; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis; D023041:Xenograft Model Antitumor Assays
D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors; D065130:Endothelin A Receptor Antagonists; D019332:Endothelin-1; D007527:Isoenzymes; D008565:Membrane Proteins; D009578:Nitrobenzenes; D011720:Pyrazoles; D011759:Pyrrolidines; D012333:RNA, Messenger; D044022:Receptor, Endothelin A; D011993:Recombinant Fusion Proteins; D013449:Sulfonamides; D042461:Vascular Endothelial Growth Factor A; C080955:N-(2-cyclohexyloxy-4-nitrophenyl)methanesulfonamide; C090859:1-((4-methylsulfonyl)phenyl)-3-trifluoromethyl-5-(4-fluorophenyl)pyrazole; D008156:Luciferases; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; C496511:PTGS1 protein, human; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; C496512:Ptgs1 protein, mouse; D015232:Dinoprostone; D000077868:Atrasentan; D007213:Indomethacin