title: Paclitaxel-induced aberrant mitosis and mitotic slippage efficiently lead to proliferative death irrespective of canonical apoptosis and p53.
abstract: Spindle poisons elicit various cellular responses following metaphase arrest, but how they relate to long-term clonogenicity has remained unclear. We prepared several HeLa lines in which the canonical apoptosis pathway was attenuated, and compared their acute responses to paclitaxel, as well as long-term fate, with the parental line. Three-nanomolar paclitaxel induced brief metaphase arrest (<5 h) often followed by aberrant mitosis, and about 90% of the cells of each line had lost their clonogenicity after 48 h of the treatment. A combination of the same concentration of paclitaxel with the kinesin-5 inhibitor, S-trityl-L-cysteine (STLC), at 1 µM led to much longer arrest (∼20 h) and predominance of subsequent line-specific responses: mitochondrial outer membrane permeabilization (MOMP) in the apoptosis-prone line, or mitotic slippage without obvious MOMP in the apoptosis-reluctant lines. In spite of this, combination with STLC did not lead to a marked difference in clonogenicity between the apoptosis-prone and -reluctant lines, and intriguingly resulted in slightly better clonogenicity than that of cells treated with 3 nM paclitaxel alone. This indicates that changes in the short-term response within 3 possible scenarios - acute MOMP, mitotic slippage or aberrant mitosis - has only a weak impact on clonogenicity. Our results suggest that once cells have committed to slippage or aberrant mitosis they eventually undergo proliferative death irrespective of canonical apoptosis or p53 function. Consistent with this, cells with irregular DNA contents originating from mitotic slippage or aberrant mitosis were mostly eliminated from the population within several rounds of division after the drug treatment.
authors.affiliation: a Department of Tumor Biology , Institute of Biomedical Sciences, Iwate Medical University , Yahaba-cho, Shiwa-gun , Iwate , Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Yasuhira
authors.affiliation: a Department of Tumor Biology , Institute of Biomedical Sciences, Iwate Medical University , Yahaba-cho, Shiwa-gun , Iwate , Japan.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Shibazaki
authors.affiliation: a Department of Tumor Biology , Institute of Biomedical Sciences, Iwate Medical University , Yahaba-cho, Shiwa-gun , Iwate , Japan.
authors.forename: Masao
authors.initials: M
authors.lastname: Nishiya
authors.affiliation: a Department of Tumor Biology , Institute of Biomedical Sciences, Iwate Medical University , Yahaba-cho, Shiwa-gun , Iwate , Japan.
authors.forename: Chihaya
authors.initials: C
authors.lastname: Maesawa
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D059447:Cell Cycle Checkpoints / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002999:Clone Cells; D003545:Cysteine / Q000031:analogs & derivatives / Q000494:pharmacology; D004247:DNA / Q000378:metabolism; D017930:Genes, Reporter; D006367:HeLa Cells; D006801:Humans; D016547:Kinesins / Q000037:antagonists & inhibitors / Q000378:metabolism; D008545:Melanoma / Q000473:pathology; D051336:Mitochondrial Membranes / Q000187:drug effects / Q000378:metabolism; D008938:Mitosis / Q000187:drug effects*; D017239:Paclitaxel / Q000494:pharmacology*; D010539:Permeability; D010641:Phenotype; D015203:Reproducibility of Results; D059008:Time-Lapse Imaging; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
chemical_list: D016159:Tumor Suppressor Protein p53; C003724:3-tritylthio-L-alanine; D004247:DNA; D016547:Kinesins; D003545:Cysteine; D017239:Paclitaxel
keywords: Aberrant mitosis; apoptosis; metaphase arrest; mitotic catastrophe; mitotic slippage; paclitaxel; spindle assembly checkpoint; spindle poison