title: Caspase-independent mitotic death (CIMD).
abstract: The spindle checkpoint, which monitors kinetochore-microtubule attachment, is required for high fidelity of chromosome transmission. A failure in this mechanism causes aneuploidy, thereby promoting progression to tumorigenesis. However, the cell death mechanism that prevents the aneuploidy caused by failure of the spindle checkpoint is yet unknown. We have recently identified a novel type of mitotic cell death, which we term caspase-independent mitotic death (CIMD). In BUB1-deficient (but not MAD2-deficient) cells, CIMD is induced by conditions that activate the spindle checkpoint (i.e., cold shock or treatment with nocodazole, paclitaxel or 17-AAG [17-allylaminogeldanamycin]). CIMD depends on p73, a homolog of p53, but not on p53. It also depends on the apoptosis-inducing factor (AIF) and endonuclease G (Endo G), which are effectors of caspase-independent cell death. When BUB1 is completely depleted, aneuploidy occurs instead of CIMD. We propose that CIMD can be the cell death mechanism that protects cells from aneuploidy by inducing the death of cells prone to substantial chromosome missegregation. Our study also shows that previous evaluations of the spindle checkpoint activity in mutant or cancer cells by monitoring mitotic index could be misleading.
authors.affiliation: Department of Molecular Pharmacology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA. katsumi.kitagawa@stjude.org
authors.forename: Katsumi
authors.initials: K
authors.lastname: Kitagawa
authors.forename: Yohei
authors.initials: Y
authors.lastname: Niikura
mesh_terms: D000818:Animals; D051033:Apoptosis Inducing Factor / Q000378:metabolism; D016923:Cell Death / Q000502:physiology*; D020090:Chromosome Segregation / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000378:metabolism; D004706:Endodeoxyribonucleases / Q000378:metabolism; D006801:Humans; D018386:Kinetochores / Q000378:metabolism*; D051379:Mice; D008870:Microtubules / Q000378:metabolism*; D008954:Models, Biological; D009687:Nuclear Proteins / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000172:deficiency / Q000378:metabolism*; D008941:Spindle Apparatus / Q000502:physiology*; D000072160:Tumor Protein p73; D025521:Tumor Suppressor Proteins / Q000378:metabolism
chemical_list: D051033:Apoptosis Inducing Factor; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; C000606460:TP73 protein, human; C000606368:Trp73 protein, mouse; D000072160:Tumor Protein p73; D025521:Tumor Suppressor Proteins; C584277:BUB1 protein, human; C584281:Bub1 protein, mouse; C090464:Bub1 spindle checkpoint protein; D017346:Protein Serine-Threonine Kinases; D004706:Endodeoxyribonucleases; C052391:endonuclease G