Ethanol metabolism activates cell cycle checkpoint kinase, Chk2

Dahn L Clemens, Katrina J. Mahan Schneider, Robert F. Nuss

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Chronic ethanol abuse results in hepatocyte injury and impairs hepatocyte replication. We have previously shown that ethanol metabolism results in cell cycle arrest at the G2/M transition, which is partially mediated by inhibitory phosphorylation of the cyclin-dependent kinase, Cdc2. To further delineate the mechanisms by which ethanol metabolism mediates this G2/M arrest, we investigated the involvement of upstream regulators of Cdc2 activity. Cdc2 is activated by the phosphatase Cdc25C. The activity of Cdc25C can, in turn, be regulated by the checkpoint kinase, Chk2, which is regulated by the kinase ataxia telangiectasia mutated (ATM). To investigate the involvement of the regulators of Cdc2 activity, VA-13 cells, which are Hep G2 cells modified to efficiently express alcohol dehydrogenase, were cultured in the presence or absence of 25 mM ethanol. Immunoblots were performed to determine the effects of ethanol metabolism on the activation of Cdc25C, Chk2, and ATM. Ethanol metabolism increased the active forms of ATM and Chk2, as well as the phosphorylated form of Cdc25C. Additionally, inhibition of ATM resulted in approximately 50% of the cells being rescued from the G2/M cell cycle arrest and ameliorated the inhibitory phosphorylation of Cdc2. Our findings demonstrated that ethanol metabolism activates ATM. ATM can activate the checkpoint kinase Chk2, resulting in phosphorylation of Cdc25C and ultimately in the accumulation of inactive Cdc2. This may, in part, explain the ethanol metabolism-mediated impairment in hepatocyte replication, which may be important in the initiation and progression of alcoholic liver injury.

Original languageEnglish (US)
Pages (from-to)785-793
Number of pages9
JournalAlcohol
Volume45
Issue number8
DOIs
StatePublished - Dec 1 2011

Fingerprint

Cell Cycle Checkpoints
Metabolism
Ataxia Telangiectasia
Ethanol
Phosphotransferases
Cells
Phosphorylation
G2 Phase Cell Cycle Checkpoints
alcoholism
Hepatocytes
activation
abuse
alcohol
cdc25 Phosphatases
Cyclin-Dependent Kinases
Alcohol Dehydrogenase
Wounds and Injuries
Hep G2 Cells
Liver
Chemical activation

Keywords

  • Alcoholic liver disease
  • Ataxia telangiectasia mutated (ATM)
  • Cdc2
  • Checkpoint kinase
  • Ethanol metabolism
  • Liver regeneration

ASJC Scopus subject areas

  • Health(social science)
  • Biochemistry
  • Toxicology
  • Neurology
  • Behavioral Neuroscience

Cite this

Ethanol metabolism activates cell cycle checkpoint kinase, Chk2. / Clemens, Dahn L; Mahan Schneider, Katrina J.; Nuss, Robert F.

In: Alcohol, Vol. 45, No. 8, 01.12.2011, p. 785-793.

Research output: Contribution to journalArticle

Clemens, Dahn L ; Mahan Schneider, Katrina J. ; Nuss, Robert F. / Ethanol metabolism activates cell cycle checkpoint kinase, Chk2. In: Alcohol. 2011 ; Vol. 45, No. 8. pp. 785-793.
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