Prostaglandin F(2alpha) is protective for apoptosis stimulated synergistically with 12-O-tetradecanoyl phorbol-beta-acetate and nordihydroguaiaretic acid in Madin-Darby canine kidney cells.
We recently found that 12-O-tetradecanoyl phorbol-beta-acetate (TPA) induced apoptosis in cultured Madin-Darby canine kidney (MDCK) cells. The present study shows that the apoptosis was mediated by the activation of caspases including caspase-3 and -7. Moreover, nordihydroguaiaretic acid (NDGA), a general lipoxygenase (LOX) inhibitor, synergistically stimulated the TPA-induced apoptosis despite no activation with NDGA alone. TPA preferentially increased the transcription of cyclooxygenase (COX)-2 in MDCK cells, whereas the expression of LOXs was almost negligible. These findings suggested that the effect of NDGA was independent of the inhibition of LOXs. The study using a cell-permeable 2',7'-dichlorofluorescin diacetate confirmed the more remarked production of reactive oxygen species at 6 h after the cells were treated with a mixture of TPA and NDGA. Calcium ionophore A23187 was markedly effective to attenuate the TPA-induced apoptosis, indicating that elevated endogenous prostaglandins (PGs) served as survival factors through not only the activation of phospholipase A(2) by A23187 but also the induction of COX-2 by TPA. Consistent with this indication, exogenous addition of PGF(2alpha), a predominant prostanoid in MDCK cells, was the most potent to protect the cells from the apoptosis induced by a mixture of TPA and NDGA.
Nishimura
Kohji
K
Department of Life Science and Biotechnology, Shimane University, Nishikawatsu-cho, Matsue, Shimane 690-8504, Japan. knishimura@life.shimane-u.ac.jp
Tsumagari
Hirohumi
H
Setoyama
Tsutomu
T
Morioka
Asami
A
Lu
Shan
S
Jisaka
Mitsuo
M
Nagaya
Tsutomu
T
Yokota
Kazushige
K
D000818:Animals; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D051546:Cyclooxygenase 2; D015237:Dinoprost / Q000494:pharmacology*; D004285:Dogs; D007527:Isoenzymes / Q000096:biosynthesis / Q000187:drug effects / Q000235:genetics; D007668:Kidney / Q000187:drug effects; D008084:Lipoxygenase / Q000096:biosynthesis / Q000187:drug effects / Q000235:genetics; D009637:Masoprocol / Q000494:pharmacology*; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis / Q000187:drug effects / Q000235:genetics; D017382:Reactive Oxygen Species / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D013997:Time Factors
D007527:Isoenzymes; D017382:Reactive Oxygen Species; D009637:Masoprocol; D015237:Dinoprost; D008084:Lipoxygenase; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases; D013755:Tetradecanoylphorbol Acetate