Survival and proliferation of cells expressing caspase-uncleavable Poly(ADP-ribose) polymerase in response to death-inducing DNA damage by an alkylating agent.
To determine whether caspase-3-induced cleavage of poly(ADP-ribose) polymerase (PARP), a DNA damage-sensitive enzyme, alters the balance between survival and death of the cells following DNA damage, we created stable cell lines that express either caspase-uncleavable mutant or wild type PARP in the background of PARP (-/-) fibroblasts. The survival and apoptotic responses of these cells were compared after exposure to N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), a DNA-damaging agent that activates PARP, or to tumor necrosis factor-alpha, which causes apoptosis without initial DNA damage. In response to MNNG, the cells with caspase-uncleavable PARP were very resistant to loss of viability or induction of apoptosis. Most significantly, approximately 25% of these cells survived and retained clonogenicity at a level of DNA damage that eliminated the cells with wild type PARP or PARP (-/-) cells. Expression of caspase-uncleavable PARP could not protect the cells from death induced by tumor necrosis factor, although there was a slower progression of apoptotic events in these cells. Therefore, one of the functions for cleavage of PARP during apoptosis induced by alkylating agents is to prevent survival of the extensively damaged cells.
Halappanavar
S S
SS
Laboratory for Skin Cancer Research, Laval University Medical Research Center, Centre Hospitalier Universitaire de Québec, Faculty of Medicine, Laval University, Quebec G1V 4G2, Canada.
Rhun
Y L
YL
Mounir
S
S
Martins
L M
LM
Huot
J
J
Earnshaw
W C
WC
Shah
G M
GM
D000477:Alkylating Agents / Q000494:pharmacology*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D020169:Caspases / Q000378:metabolism*; D002455:Cell Division; D002460:Cell Line; D002470:Cell Survival; D004247:DNA / Q000187:drug effects*; D004249:DNA Damage; D020287:In Situ Nick-End Labeling; D008769:Methylnitronitrosoguanidine / Q000494:pharmacology*; D051379:Mice; D011065:Poly(ADP-ribose) Polymerases / Q000502:physiology*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D000477:Alkylating Agents; D014409:Tumor Necrosis Factor-alpha; D008769:Methylnitronitrosoguanidine; D004247:DNA; D011065:Poly(ADP-ribose) Polymerases; D020169:Caspases