title: [Dexamethasone-induced apoptosis of murine MIN6 pancreatic beta-cells and its effect on AKT phosphorylation].
abstract: This study is to investigate the effect of dexamethasone on cell apoptosis of murine MIN6 pancreatic beta-cells, and to investigate the mechanism of dexamethasone-dependent cell apoptosis. The cell apoptosis model was established by choosing the murine MIN6 pancreatic beta-cells, which was cultured in vitro and induced by dexamethasone. The morphology of the cell apoptosis was observed through fluorescence microscopic analysis after Hochest/PI staining and flow cytometric assay after Annexin-V/PI staining. The expression of caspase-3 was detected with caspase-3 activity assay kit. The expressions of Cyt-c, Bcl-2, Bax, AKT and p-AKT were observed with Western blotting. The results indicated that after exposure to dexamethasone at a concentration ranging from 50-800 nmol x L(-1) for 48 h, the percentage of cell apoptosis was significantly increased with the concentration over 100 nmol x L(-1) of dexamethasone; after exposure to dexamethasone (100 nmol x L(-1)) for 72 h, the activity of caspase-3 increased significantly; after exposure to dexamethasone at a concentration ranging from 50-800 nmol x L(-1) for 48 h, the expression of Cyt-c increased, Bcl-2 and AKT phosphorylation decreased while Bax and T-AKT remained unchanged. It could be concluded that the effect of dexamethasone on murine MIN6 pancreatic beta-cells apoptosis is significant. The mechanism of dexamethasone-dependent cell apoptosis is probably related to down regulation of the Bcl-2 expression and reduction of AKT phosphorylation.
authors.affiliation: Fujian Endocrinology Institute, Affiliated Union Hospital, Fujian Medical University, Fuzhou 350001, China.
authors.forename: Lin-xi
authors.initials: LX
authors.lastname: Wang
authors.forename: Yan-ping
authors.initials: YP
authors.lastname: Wang
authors.forename: Xiao-ying
authors.initials: XY
authors.lastname: Liu
authors.forename: Liang
authors.initials: L
authors.lastname: Liu
authors.forename: Li-jing
authors.initials: LJ
authors.lastname: Wang
authors.forename: Wen-jia
authors.initials: WJ
authors.lastname: Chen
authors.forename: Xiao-hong
authors.initials: XH
authors.lastname: Liu
authors.forename: Li-bin
authors.initials: LB
authors.lastname: Liu
mesh_terms: D000818:Animals; D018931:Antineoplastic Agents, Hormonal / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3 / Q000378:metabolism; D002460:Cell Line; D045304:Cytochromes c / Q000378:metabolism; D003907:Dexamethasone / Q000494:pharmacology*; D015536:Down-Regulation; D050417:Insulin-Secreting Cells / Q000378:metabolism / Q000473:pathology*; D051379:Mice; D010766:Phosphorylation; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D051028:bcl-2-Associated X Protein / Q000378:metabolism
chemical_list: D018931:Antineoplastic Agents, Hormonal; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; D003907:Dexamethasone; D045304:Cytochromes c; D051057:Proto-Oncogene Proteins c-akt; D053148:Caspase 3