title: Mifepristone increases the cytotoxicity of uterine natural killer cells by acting as a glucocorticoid antagonist via ERK activation.
abstract: BACKGROUND
  Mifepristone (RU486), a potent antagonist of progesterone and glucocorticoids, is involved in immune regulation. Our previous studies demonstrated that mifepristone directly augments the cytotoxicity of human uterine natural killer (uNK) cells. However, the mechanism responsible for this increase in cytotoxicity is not known. Here, we explored whether the increased cytotoxicity in uNK cells produced by mifepristone is due to either anti-progesterone or anti-glucocorticoid activity, and also investigated relevant changes in the mitogen-activated protein kinase (MAPK) pathway.
  
  
  RESULTS
  Uterine NK cells were isolated from decidual samples and incubated with different concentrations of progesterone, cortisol, or mifepristone. The cytotoxicity and perforin expression of uNK cells were detected by mitochondrial lactate dehydrogenase-based MTS staining and flow cytometry assays, respectively. Phosphorylation of components of the MAPK signaling pathway was detected by Western blot. Cortisol attenuated uNK cell-mediated cytotoxicity in a concentration-dependent manner whereas progesterone had no effect. Mifepristone alone increased the cytotoxicity and perforin expression of uNK cells; these effects were blocked by cortisol. Furthermore, mifepristone increased the phosphorylation of ERK1/2 in a cortisol-reversible manner. Specific ERK1/2 inhibitor PD98059 or U0126 blocked cortisol- and mifepristone-induced responses in uNK cells.
  
  
  CONCLUSIONS
  These results suggest that mifepristone acts as a glucocorticoid antagonist to augment uNK cell-mediated cytotoxicity via ERK activation, which may be caused by increased perforin expression. These observations may reveal an important mechanism by which mifepristone upregulates the cytotoxicity of uNK cells.
authors.affiliation: Women's Reproductive Health Laboratory of Zhejiang Province, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, People's Republic of China.
authors.forename: Yuezhou
authors.initials: Y
authors.lastname: Chen
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.forename: Yaling
authors.initials: Y
authors.lastname: Zhuang
authors.forename: Feng
authors.initials: F
authors.lastname: Zhou
authors.forename: Lili
authors.initials: L
authors.lastname: Huang
mesh_terms: D000328:Adult; D015153:Blotting, Western; D002070:Butadienes / Q000494:pharmacology; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D003656:Decidua / Q000166:cytology; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D005419:Flavonoids / Q000494:pharmacology; D005938:Glucocorticoids / Q000037:antagonists & inhibitors*; D006727:Hormone Antagonists / Q000494:pharmacology; D006801:Humans; D006854:Hydrocortisone / Q000494:pharmacology; D020014:K562 Cells; D007694:Killer Cells, Natural / Q000187:drug effects* / Q000378:metabolism; D015735:Mifepristone / Q000494:pharmacology*; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009570:Nitriles / Q000494:pharmacology; D054353:Perforin / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D011247:Pregnancy; D015854:Up-Regulation / Q000187:drug effects; D055815:Young Adult
chemical_list: D002070:Butadienes; D004791:Enzyme Inhibitors; D005419:Flavonoids; D005938:Glucocorticoids; D006727:Hormone Antagonists; D009570:Nitriles; C113580:U 0126; D054353:Perforin; D015735:Mifepristone; C535150:MAPK1 protein, human; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one; D006854:Hydrocortisone