U2OS cells lacking Chk1 undergo aberrant mitosis and fail to activate the spindle checkpoint

Laura Carrassa, Yolanda Sanchez, Eugenio Erba, Giovanna Damia

Research output: Contribution to journalArticle

32 Citations (Scopus)

Abstract

Chk1 is a conserved protein kinase originally identified in fission yeast, required to delay entry of cells with damaged or unreplicated DNA into mitosis. The requirement of Chk1 for both S and G2/M checkpoints has been elucidated while only few studies have connected Chk1 to the mitotic spindle checkpoint. We used a small interference RNA strategy to investigate the role of Chk1 in unstressed conditions. Chk1 depletion in U2OS human osteosarcoma cells inhibited cell proliferation and raised the percentage of cells with a 4N DNA content, which correlated with accumulation of giant polynucleated cells morphologically distinct from apoptotic cells, while no increased number of cells in G2 or mitosis could be detected. Down-regulation of Chk1 also caused accumulation of cells in the last step of cytokinesis, and of tetraploid cells in G1 phase, which coincided with activation of p53 and increased levels of p21. In addition, Chk1-depleted U2OS cells failed to arrest in mitosis after spindle disruption by nocodazole and showed decreased protein levels of Mad2 and BubR1. These studies show that U2OS cells lacking Chk1 undergo abnormal mitosis and fail to activate the spindle checkpoint, suggesting a role of Chk1 in this checkpoint.

Original languageEnglish
Pages (from-to)1565-1576
Number of pages12
JournalJournal of Cellular and Molecular Medicine
Volume13
Issue number8 A
DOIs
Publication statusPublished - Aug 2009

Fingerprint

Mitosis
Mad2 Proteins
M Phase Cell Cycle Checkpoints
Nocodazole
Cytokinesis
Tetraploidy
Schizosaccharomyces
DNA
G1 Phase
Osteosarcoma
Giant Cells
RNA Interference
Protein Kinases
Down-Regulation
Cell Count
Cell Proliferation

Keywords

  • Cell cycle
  • Chk1
  • Mitosis
  • SiRNA
  • Spindle checkpoint
  • Tetraploidy

ASJC Scopus subject areas

  • Cell Biology
  • Molecular Medicine

Cite this

U2OS cells lacking Chk1 undergo aberrant mitosis and fail to activate the spindle checkpoint. / Carrassa, Laura; Sanchez, Yolanda; Erba, Eugenio; Damia, Giovanna.

In: Journal of Cellular and Molecular Medicine, Vol. 13, No. 8 A, 08.2009, p. 1565-1576.

Research output: Contribution to journalArticle

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