Overexpression of EVI1 interferes with cytokinesis and leads to accumulation of cells with supernumerary centrosomes in G0/1 phase.
Ectopic viral integration site 1 (EVI1), a transcription factor frequently overexpressed in myeloid neoplasias, has been implicated in the generation of malignancy-associated centrosomal aberrations and chromosomal instability. Here, we sought to investigate the underlying cause of centrosome amplification in EVI1-overexpressing cells. We found that overexpression of EVI1-HA in U2OS cells induced supernumerary centrosomes, which were consistently associated with enlarged nuclei or binuclear cells. Live cell imaging experiments identified cytokinesis failure as the underlying cause of this phenotype. In accordance with previous reports, EVI1 overexpression induced a partial cell cycle arrest in G0/1 phase, accompanied by elevated cyclin D1 and p21 levels, reduced Cdk2 activity and activation of the p53 pathway. Supernumerary centrosomes predominantly occurred in resting cells, as identified by low levels of the proliferation marker Ki-67, leading to the conclusion that they result from tetraploidization after cytokinesis failure and are confined to G0/1-arrested tetraploid cells. Depletion of p53 using siRNA revealed that further polyploidization of these cells was inhibited by the p53-dependent tetraploidy checkpoint.
Clinical Cooperation Unit Molecular Hematology/Oncology, German Cancer Research Center (DKFZ) and Department of Internal Medicine V, University of Heidelberg; Heidelberg, Germany.
Kadin
K
Karakaya
Friederike
F
Herbst
Claudia
C
Ball
Hanno
H
Glimm
Alwin
A
Krämer
Harald
H
Löffler
D059447:Cell Cycle Checkpoints; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism; D049109:Cell Proliferation; D018385:Centrosome / Q000378:metabolism*; D019938:Cyclin D1 / Q000378:metabolism; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism; D048749:Cytokinesis; D004268:DNA-Binding Proteins / Q000378:metabolism*; D025461:Feedback, Physiological; D016193:G1 Phase; D006801:Humans; D019394:Ki-67 Antigen / Q000378:metabolism; D000074008:MDS1 and EVI1 Complex Locus Protein; D011123:Polyploidy; D011519:Proto-Oncogenes; D016192:Resting Phase, Cell Cycle; D015398:Signal Transduction; D014157:Transcription Factors / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
C530104:CCND1 protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D004268:DNA-Binding Proteins; D019394:Ki-67 Antigen; D000074008:MDS1 and EVI1 Complex Locus Protein; C063575:MECOM protein, human; D014157:Transcription Factors; D016159:Tumor Suppressor Protein p53; D019938:Cyclin D1