Involvement of poly(ADP-ribose) polymerase activity in regulating Chk1-dependent apoptotic cell death.

Abstract

The activity of poly(ADP-ribose) polymerase (PARP) is highly stimulated following DNA damage resulting in formation of DNA nicks and strand breaks. This leads to modification of numerous proteins, including itself, using NAD(+) as substrate and to exhaustion of intracellular ATP. A highly cytotoxic concentration of the DNA methylating agent methyl methanesulfonate (MMS) results in cellular ATP depletion and cell death primarily by necrosis in both wild-type and DNA polymerase beta null mouse fibroblasts. The loss of ATP can be prevented by the PARP inhibitor 4-amino-1,8-naphthalimide (4-AN), and now cells die by an energy-dependent apoptotic pathway. We find that inhibition of PARP activity transforms a sub-lethal exposure to MMS into a highly cytotoxic event. Under this condition, ATP is not depleted and cell death is by apoptosis. The caspase inhibitor, Z-VAD, shifts the mechanism of cell death to necrosis indicating a caspase-dependent component of the apoptotic cell death. Co-exposure to the Chk1 inhibitor UCN-01 also produces a decrease in apoptotic cell death, but now there is an increase in viable cells and an enhancement in long-term survival. Taken together, our results suggest that inhibition of PARP activity, induced as a result of low dose MMS exposure, signals via a Chk1-dependent pathway for cell death by apoptosis.

• Authors: Julie K Horton, Donna F Stefanick, Samuel H Wilson
• Journal: DNA repair (DNA Repair (Amst)) Vol. 4 Issue 10 Pg. 1111-20 (Sep 28 2005) ISSN: 1568-7864 [Print] Netherlands
• PMID: 16002346 (Publication Type: Journal Article)

Chemical References

• Amino Acid Chloromethyl Ketones
• Caspase Inhibitors
• Poly(ADP-ribose) Polymerase Inhibitors
• benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone
• Adenosine Triphosphate
• DNA
• Methyl Methanesulfonate
• Poly(ADP-ribose) Polymerases
• Protein Kinases
• Checkpoint Kinase 1
• Chek1 protein, mouse

Topics

• Adenosine Triphosphate (metabolism)
• Amino Acid Chloromethyl Ketones (pharmacology)
• Animals
• Apoptosis
• Caspase Inhibitors
• Cells, Cultured
• Checkpoint Kinase 1
• DNA (drug effects)
• Fibroblasts (drug effects, enzymology)
• Methyl Methanesulfonate (toxicity)
• Mice
• Mutation
• Necrosis
• Poly(ADP-ribose) Polymerase Inhibitors
• Poly(ADP-ribose) Polymerases (genetics, metabolism)
• Protein Kinases (metabolism)