title: Peroxisome proliferator-activated receptor-gamma suppresses cyclooxygenase-2 expression in human prostate cells.
abstract: Recent studies have found that cyclooxygenase-2 (COX-2) protein expression was low and inducible with cytokines in prostate cancer cells (in the absence of serum) and that, in contrast, COX-2 expression was high in normal prostate epithelial cells (EC). Peroxisome proliferator-activated receptor-gamma (PPAR-gamma) was expressed at high levels in the prostate cancer cell line PC-3 but not in ECs. In contrast to previous findings by others, PPAR-gamma ligands did not induce PPAR-gamma expression in EC or PC-3. The present study examined the relationship between PPAR-gamma and COX-2 expression patterns in EC and PC-3 in the presence and absence of serum and/or the PPAR-gamma agonist 15-deoxy-Delta12,14-prostaglandin J(2) (15d-PGJ(2)). We also evaluated the effects that the forced expression of PPAR-gamma1 and PPAR-gamma2 had on COX-2 in ECs. We found that expression of PPAR-gamma and COX-2 protein was inversely correlated in ECs and PC-3. Low COX-2 expression in PC-3 was up-regulated by serum, and 15d-PGJ(2) blocked serum-induced COX-2 expression and activity in a dose-dependent manner. 15d-PGJ(2) had no effect on COX-2 expression in ECs or PPAR-gamma expression in either cell type. However, forced expression of PPAR-gamma1 or PPAR-gamma2 in ECs suppressed the high level of endogenous COX-2. This effect was not isoform specific and was augmented by 15d-PGJ(2). The present study showed that PPAR-gamma activation can be an important regulator of COX-2 in prostate cells and may be an important target for prostate cancer chemoprevention.
authors.affiliation: Department of Clinical Cancer Prevention, Unit 236, University of Texas M.D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA.
authors.forename: Anita L
authors.initials: AL
authors.lastname: Sabichi
authors.forename: Vemparala
authors.initials: V
authors.lastname: Subbarayan
authors.forename: Norma
authors.initials: N
authors.lastname: Llansa
authors.forename: Scott M
authors.initials: SM
authors.lastname: Lippman
authors.forename: David G
authors.initials: DG
authors.lastname: Menter
mesh_terms: D002478:Cells, Cultured; D051546:Cyclooxygenase 2; D015536:Down-Regulation / Q000187:drug effects; D004727:Endothelium / Q000187:drug effects / Q000201:enzymology; D006801:Humans; D007527:Isoenzymes / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D008297:Male; D008565:Membrane Proteins; D047495:PPAR gamma / Q000819:agonists / Q000494:pharmacology / Q000502:physiology*; D015230:Prostaglandin D2 / Q000031:analogs & derivatives* / Q000494:pharmacology*; D011451:Prostaglandin-Endoperoxide Synthases / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D011467:Prostate / Q000187:drug effects / Q000201:enzymology*; D014162:Transfection
chemical_list: C477819:15-deoxyprostaglandin J2; D007527:Isoenzymes; D008565:Membrane Proteins; D047495:PPAR gamma; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D015230:Prostaglandin D2