title: Mitotic catastrophe and cell death induced by depletion of centrosomal proteins.
abstract: Mitotic catastrophe, which refers to cell death or its prologue triggered by aberrant mitosis, can be induced by a heterogeneous group of stimuli, including chromosome damage or perturbation of the mitotic apparatus. We investigated the mechanism of mitotic catastrophe and cell death induced by depletion of centrosomal proteins that perturbs microtubule organization. We transfected cells harboring wild-type or mutated p53 with siRNAs targeting Aurora A, ninein, TOG, TACC3, γ-tubulin, or pericentriolar material-1, and monitored the effects on cell death. Knockdown of Aurora A, ninein, TOG, and TACC3 led to cell death, regardless of p53 status. Knockdown of Aurora A, ninein, and TOG, led to aberrant spindle formation and subsequent cell death, which was accompanied by several features of apoptosis, including nuclear condensation and Annexin V binding in HeLa cells. During this process, cleavage of poly(ADP-ribose) polymerase-1, caspase-3, and caspase-9 was detected, but cleavage of caspase-8 was not. Cell death, monitored by time-lapse imaging, occurred during both interphase and M phase. In cells depleted of a centrosomal protein (Aurora A, ninein, or TOG), the rate of cell death was higher if the cells were cotransfected with siRNA against BubR1 or Mad2 than if they were transfected with siRNA against Bub1 or a control siRNA. These results suggest that metaphase arrest is necessary for the mitotic catastrophe and cell death caused by depletion of centrosomal proteins. Knockdown of centrosomal proteins led to increased phosphorylation of Chk2. Enhanced p-Chk2 localization was also observed at the centrosome in cells arrested in M phase, as well as in the nuclei of dying cells. Cotransfection of siRNAs against Chk2, in combination with depletion of a centrosomal protein, decreased the amount of cell death. Thus, Chk2 activity is indispensable for apoptosis after mitotic catastrophe induced by depletion of centrosomal proteins that perturbs microtubule organization.
authors.affiliation: Department of Molecular Pathobiochemistry, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Kimura
authors.forename: T
authors.initials: T
authors.lastname: Yoshioka
authors.forename: M
authors.initials: M
authors.lastname: Saio
authors.forename: Y
authors.initials: Y
authors.lastname: Banno
authors.forename: H
authors.initials: H
authors.lastname: Nagaoka
authors.forename: Y
authors.initials: Y
authors.lastname: Okano
mesh_terms: D017209:Apoptosis; D064127:Aurora Kinases; D001324:Autoantigens / Q000235:genetics / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D002455:Cell Division; D045744:Cell Line, Tumor; D018385:Centrosome / Q000378:metabolism*; D064447:Checkpoint Kinase 2; D003598:Cytoskeletal Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D045325:HCT116 Cells; D006367:HeLa Cells; D006801:Humans; D007399:Interphase; D008869:Microtubule-Associated Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D008938:Mitosis; D009687:Nuclear Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D008941:Spindle Apparatus / Q000378:metabolism; D059008:Time-Lapse Imaging; D014404:Tubulin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism
chemical_list: D001324:Autoantigens; D018797:Cell Cycle Proteins; D003598:Cytoskeletal Proteins; D008869:Microtubule-Associated Proteins; C512806:NIN protein, human; D009687:Nuclear Proteins; C086074:PCM1 protein, human; D034741:RNA, Small Interfering; C120551:TACC3 protein, human; D014404:Tubulin; D016159:Tumor Suppressor Protein p53; D064447:Checkpoint Kinase 2; D064127:Aurora Kinases; C578634:CHEK2 protein, human; D017346:Protein Serine-Threonine Kinases