Raloxifene analogue LY117018 suppresses oxidative stress-induced endothelial cell apoptosis through activation of ERK1/2 signaling pathway.
A selective estrogen receptor modulator, raloxifene, has been shown to reduce cardiovascular events in relatively high-risk postmenopausal women with osteoporosis. However, the mechanisms by which raloxifene exerts a pharmacological effect on cardiovascular organs have not been fully elucidated. The present study was designed to examine whether the raloxifene analogue, 6-hydroxy-2-(p-hydroxyphenyl)-benzo(b) thien-3-yl-p-(2-(pyrrolidinyl)ethoxy phenyl ketone (LY117018), could inhibit apoptosis and to clarify the signaling pathway in vascular endothelial cells. LY117018 significantly inhibited hydrogen peroxide-induced apoptosis in bovine carotid artery endothelial cells. The anti-apoptotic effect of LY117018 was abolished by an estrogen receptor antagonist, 7alpha,7beta-(9[(4,4,5,5,5-Pentafluoropentyl)sulfinyl]nonyl) estra-1,3,5(10)-triene-3,17-diol (ICI 182,780). Mitogen-activated protein kinases (MAPK), including p38, c-Jun N-terminal kinase (JNK) and extracellular signal-regulated protein kinase1/2 (ERK1/2), and Akt, have been shown to act as apoptotic or anti-apoptotic signals. Phosphorylation of p38, JNK, ERK1/2 and Akt was examined. LY117018 increased ERK1/2 phosphorylation but did not enhance the phosphorylation of p38, JNK, or Akt. The anti-apoptotic effect of LY117018 was prevented by treatment with 2-[2'-amino-3'-methoxyphenyl]-oxanaphthalen-4-one (PD98059), an upstream inhibitor of ERK1/2. LY117018 stimulated an increase in ERK1/2 phosphorylation, which was diminished by ICI 182,780. The activation of ERK/1/2 by LY117018 was not inhibited by the transcription inhibitor, actinomycin D. These results suggest that estrogen receptors and the ERK1/2 signaling pathway are involved in the anti-apoptotic action of LY117018 in vascular endothelial cells.
Yu
Jing
J
Department of Geriatric Medicine, Graduate School of Medicine, University of Tokyo, Tokyo, Japan.
Eto
Masato
M
Kozaki
Koichi
K
Akishita
Masahiro
M
Okabe
Tetsuro
T
Ouchi
Yasuyoshi
Y
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D002417:Cattle; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D042783:Endothelial Cells / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D004789:Enzyme Activation; D004958:Estradiol / Q000031:analogs & derivatives / Q000633:toxicity; D004965:Estrogen Antagonists / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D000077267:Fulvestrant; D006861:Hydrogen Peroxide / Q000633:toxicity; D020935:MAP Kinase Signaling System / Q000187:drug effects; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D016877:Oxidants / Q000633:toxicity; D018384:Oxidative Stress / Q000187:drug effects*; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011759:Pyrrolidines / Q000494:pharmacology*; D020849:Raloxifene Hydrochloride / Q000031:analogs & derivatives / Q000494:pharmacology*; D011960:Receptors, Estrogen / Q000187:drug effects / Q000378:metabolism; D020845:Selective Estrogen Receptor Modulators / Q000494:pharmacology*; D013876:Thiophenes / Q000494:pharmacology*
D004965:Estrogen Antagonists; D005419:Flavonoids; D016877:Oxidants; D047428:Protein Kinase Inhibitors; D011759:Pyrrolidines; D011960:Receptors, Estrogen; D020845:Selective Estrogen Receptor Modulators; D013876:Thiophenes; D000077267:Fulvestrant; D020849:Raloxifene Hydrochloride; D004958:Estradiol; C025430:LY 117018; D006861:Hydrogen Peroxide; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one