title: Induction of proliferation by 15-deoxy-delta12,14-prostaglandin J2 and the precursors in monocytic leukemia U937.
abstract: Peroxisome proliferator-activated receptor gamma (PPARgamma) is expressed in several human tumors including gastric, lung, colon, prostate and breast. However, the role of PPARgamma signals in leukemia is still unclear. The aim of this study is to evaluate the ability of 15-deoxy-Delta12,14-prostaglandin J2 (15dPGJ2), that is a ligand for PPARgamma, on proliferation of human leukemia cell line U937. 15dPGJ2 at 5 micromol/l stimulated the proliferation. In contrast, 15dPGJ2 at concentrations of >10 micromol/l inhibited the proliferation through the induction of apoptosis. PGD2, PGJ2 and Delta12-PGJ2 (DeltaPGJ2), those are precursors of 15dPGJ2, had similarly proliferative effects, whereas they showed antiproliferative effects at high concentrations. FACScan analysis revealed that PGD2 at 5 micromol/l, PGJ2 at 1 micromol/l, DeltaPGJ2 at 1 micromol/l and 15dPGJ2 at 5 micromol/l, all accelerated cell cycle progression. Immunoblotting analysis revealed that PGD2 at 5 micromol/l and 15dPGJ2 at 5 micromol/l inhibited the expression of phospho-p38, phospho-MKK3/MKK6 and phospho-ATF-2, and the expression of Cdk inhibitors including p18, p27. In contrast, PGJ2 at 1 micromol/l and DeltaPGJ2 at 1 micromol/l did not affect the expression of them. These results suggest that 15dPGJ2 and PGD2 may, through inactivation of the p38 MAPK pathway, inhibit the expression of Cdk inhibitors, leading to acceleration of proliferation.
authors.affiliation: Department of Pharmacology, Osaka Dental University, Hirakata, Osaka, Japan.
authors.forename: Yasutaka
authors.initials: Y
authors.lastname: Azuma
authors.forename: Kyoko
authors.initials: K
authors.lastname: Watanabe
authors.forename: Masataka
authors.initials: M
authors.lastname: Date
authors.forename: Michiharu
authors.initials: M
authors.lastname: Daito
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Ohura
mesh_terms: D017209:Apoptosis; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D018844:Cyclin-Dependent Kinases / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007948:Leukemia, Monocytic, Acute / Q000473:pathology*; D008024:Ligands; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors; D015230:Prostaglandin D2 / Q000031:analogs & derivatives / Q000494:pharmacology*; D018160:Receptors, Cytoplasmic and Nuclear / Q000819:agonists*; D014157:Transcription Factors / Q000819:agonists*; D020298:U937 Cells; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: C097240:15-deoxy-delta(12,14)-prostaglandin J2; D008024:Ligands; D018160:Receptors, Cytoplasmic and Nuclear; D014157:Transcription Factors; D018844:Cyclin-Dependent Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D015230:Prostaglandin D2