title: Chromosomal breaks during mitotic catastrophe trigger γH2AX-ATM-p53-mediated apoptosis.
abstract: Although the cause and outcome of mitotic catastrophe (MC) has been thoroughly investigated, precisely how the ensuing lethality is regulated during or following this process and what signals are involved remain unknown. Moreover, the mechanism of the decision of cell death modalities following MC is still not well characterised. We demonstrate here a crucial role of the γH2AX-ATM-p53 pathway in the regulation of the apoptotic outcome of MC resulting from cells entering mitosis with damaged DNA. In addition to p53 deficiency, the depletion of ATM (ataxia telangiectasia mutated), but not ATR (ataxia telangiectasia and Rad3-related protein), protected against apoptosis and shifted cell death towards necrosis. Activation of this pathway is triggered by the augmented chromosomal damage acquired during anaphase in doxorubicin-treated cells lacking 14-3-3σ (also known as epithelial cell marker protein-1 or stratifin). Moreover, cells that enter mitosis with damaged DNA encounter segregation problems because of their abnormal chromosomes, leading to defects in mitotic exit, and they therefore accumulate in G1 phase. These multi- or micronucleated cells are prevented from cycling again in a p53- and p21-dependent manner, and subsequently die. Because increased chromosomal damage resulting in extensive H2AX phosphorylation appears to be a direct cause of catastrophic mitosis, our results describe a mechanism that involves generation of additional DNA damage during MC to eliminate chromosomally unstable cells.
authors: Division of Toxicology, Institute of Environmental Medicine, Karolinska Institutet, SE-17177 Stockholm, Sweden.
authors: Gabriela
authors: G
authors: Imreh
authors: Helin Vakifahmetoglu
authors: HV
authors: Norberg
authors: Stefan
authors: S
authors: Imreh
authors: Boris
authors: B
authors: Zhivotovsky
mesh_terms: D048948:14-3-3 Proteins / Q000172:deficiency / Q000235:genetics; D017209:Apoptosis / Q000235:genetics*; D064007:Ataxia Telangiectasia Mutated Proteins; D014408:Biomarkers, Tumor / Q000172:deficiency / Q000235:genetics; D020169:Caspases / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002842:Chromatids / Q000187:drug effects / Q000235:genetics; D002869:Chromosome Aberrations / Q000139:chemically induced; D019457:Chromosome Breakage; D004249:DNA Damage; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004317:Doxorubicin / Q000494:pharmacology; D005092:Exonucleases / Q000172:deficiency / Q000235:genetics; D005095:Exoribonucleases; D016193:G1 Phase / Q000235:genetics; D055786:Gene Knockout Techniques; D042822:Genomic Instability; D045325:HCT116 Cells; D006657:Histones / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008938:Mitosis / Q000235:genetics*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D016196:S Phase / Q000235:genetics; D015398:Signal Transduction; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D048948:14-3-3 Proteins; D014408:Biomarkers, Tumor; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; C468783:H2AX protein, human; D006657:Histones; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; D004317:Doxorubicin; C576324:ATM protein, human; C576597:ATR protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; D017346:Protein Serine-Threonine Kinases; D005092:Exonucleases; D005095:Exoribonucleases; C413442:SFN protein, human; D020169:Caspases