Document Detail

Human cancer cells require ATR for cell cycle progression following exposure to ionizing radiation.
MedLine Citation:
PMID:  17043640     Owner:  NLM     Status:  MEDLINE    
The vast majority of cancer cells have defective checkpoints that permit the cell cycle to progress in the presence of double-strand DNA breaks (DSBs) caused by ionizing radiation (IR) and radiomimetic drugs. ATR (ataxia telangiectasia-mutated and Rad3-related) has recently been shown to be activated by DSBs, although the consequences of this activity are largely unknown. In this report, we use advanced gene targeting methods to generate biallelic hypomorphic ATR mutations in human colorectal cancer cells and demonstrate that progression of the cancer cell cycle after IR treatment requires ATR. Cells with mutant ATR accumulated at a defined point at the beginning of the S phase after IR treatment and were unable to progress beyond that point, whereas cells at later stages of the S phase during the time of irradiation progressed and completed DNA replication. The prolonged arrest of ATR mutant cancer cells did not involve the ataxia telangiectasia mutated-dependent S-phase checkpoint, but rather closely resembled a previously characterized form of cell cycle arrest termed S-phase stasis. As ATR strongly contributed to clonogenic survival after IR treatment, these data suggest that blocking ATR activity might be a useful strategy for inducing S-phase stasis and promoting the radiosensitization of checkpoint-deficient cancer cells.
P J Hurley; D Wilsker; F Bunz
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2006-10-16
Journal Detail:
Title:  Oncogene     Volume:  26     ISSN:  0950-9232     ISO Abbreviation:  Oncogene     Publication Date:  2007 Apr 
Date Detail:
Created Date:  2007-04-19     Completed Date:  2007-05-24     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  8711562     Medline TA:  Oncogene     Country:  England    
Other Details:
Languages:  eng     Pagination:  2535-42     Citation Subset:  IM    
Department of Radiation Oncology and Molecular Radiation Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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MeSH Terms
Ataxia Telangiectasia
Cell Cycle Proteins / metabolism,  physiology*
Colorectal Neoplasms / metabolism,  pathology*
DNA Breaks, Double-Stranded
DNA Repair
DNA Replication
Protein-Serine-Threonine Kinases / physiology*
Radiation, Ionizing
S Phase / physiology*
Tumor Cells, Cultured / radiation effects
Grant Support
Reg. No./Substance:
0/Cell Cycle Proteins; EC 2.7.1.-/ATR protein, human; EC Kinases

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