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Cell Biology International (2005) 29, 10051011 (Printed in Great Britain)
Segregation of genomes in polyploid tumour cells following mitotic catastrophe
Jekaterina Erenpreisaa*, M. Kalejsa, F. Ianzinibcd, E.A. Kosmacekc, M.A. Mackeybc, D. Emzinshe, M.S. Craggfg, A. Ivanovah and T.M. Illidgeh
aBiomedicine Centre of the Latvia University, Ratsupites 1, Riga LV-1067, Latvia
bDepartment Pathology, University of Iowa, Iowa City, IA, USA
cDepartment Biomedical Engineering, University of Iowa, Iowa City, IA, USA
dDepartment of Radiation Oncology, University of Iowa, Iowa City, IA, USA
eOncology Centre of Latvia, Riga, Latvia
fUniversity of Southampton, Southampton, UK
gWEHI, Melbourne, Australia
hPaterson Cancer Research Institute, Manchester, UK
Following irradiation p53-function-deficient tumour cells undergo mitotic catastrophe and form endopolyploid cells. A small proportion of these segregates nuclei, and give rise to viable descendants. Here we studied this process in five tumour cell lines. After mitotic failure, tumour cells enter the endocycle and form mono-nucleated or multi-nucleated giant cells (MOGC and MNGC). MNGC arise from arrested anaphases, MOGC, from arrested metaphases. In both cases the individual genomes establish a radial pattern by links to a single microtubule organizing centre. Segregation of genomes is also ordered. MNGC present features of mitosis being resumed from late anaphase. In MOGC the sub-nuclei retain arrangement of stacked metaphase plates and are separated by folds of the nuclear envelope. Mitosis then resumes in sub-nuclei directly from metaphase. The data presented indicate that endopolyploid tumour cells preserve the integrity of individual genomes and can potentially re-initiate mitosis from the point at which it was interrupted.
Key words: Radial arrangement of genomes, Link to microtubule-organising centre, De-polyploidisation, Resuming of mitosis, Mitotic catastrophe.
*Corresponding author. Tel.: +371 7 808 220; fax: +371 7 442 407.