title: [Simvastatin-induced apoptosis of K562 cells is mediated by endoplasmic reticulum stress].
abstract: To explore the apoptotic effect of simvastatin on K562 cells through endoplasmic reticulum stress, morphological change of apoptotic cells was observed by Hoechst33258 fluorescent staining under fluorescent microscope. Apoptosis rate of cells was determined with annexinV-FITC/PI double staining by flow cytometry; Intracellular calcium concentration ([Ca2+]i) was measured by laser scanning confocal microscope (LSCM); The expression levels of glucose regulated protein 78 (GRP78) and calpain gene mRNA were determined by RT-PCR; The expression levels of caspase-3, -6, -7, -9, -12, calpain and GRP78 proteins were evaluated by Western blotting. In this study, K562 cells treated with simvastatin for 72 h exhibited typical morphological change of apoptosis cells. After 72 h exposed to 10, 20, 30 micromol x L(-1) simvastatin, the apoptotic rates of K562 cells were 12.41%, 19.08% and 23.41%, respectively. Simvastatin induced the increase of [Ca2+]i in K562 cells, fluorescent intensities were 43, 54, and 64, respectively. The expression levels of GRP78 and calpain gene mRNA were up-regulated. The cleavage and activation of caspase-3, -6, -7, -9, -12 and upregulation of GRP78 expression were determined by Western blotting. These findings suggest that endoplasmic reticulum is an important pathway of apoptosis in cells and participates simvastatin-induced apoptosis in K562 cells. It is implied that simvastatin may be suitable for clinical usage in the treatment of myeloma patients.
authors.affiliation: Department of Laboratory Medicine of Chongqing Medical University, Chongqing 400016, China.
authors.forename: Guo-Qiang
authors.initials: GQ
authors.lastname: Xu
authors.forename: Wen-Fang
authors.initials: WF
authors.lastname: Huang
authors.forename: Hua
authors.initials: H
authors.lastname: Liu
authors.forename: Yong-Chang
authors.initials: YC
authors.lastname: Yang
authors.forename: Wen
authors.initials: W
authors.lastname: Liu
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D002118:Calcium / Q000378:metabolism; D002154:Calpain / Q000235:genetics / Q000378:metabolism; D020169:Caspases / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism*; D000091342:Endoplasmic Reticulum Chaperone BiP; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D020014:K562 Cells; D012333:RNA, Messenger / Q000378:metabolism; D019821:Simvastatin / Q000494:pharmacology*; D019284:Thapsigargin / Q000494:pharmacology
chemical_list: D000091342:Endoplasmic Reticulum Chaperone BiP; D004791:Enzyme Inhibitors; C000717247:HSPA5 protein, human; D006360:Heat-Shock Proteins; D012333:RNA, Messenger; D019284:Thapsigargin; D019821:Simvastatin; D002154:Calpain; D020169:Caspases; D002118:Calcium