Loss of the Fanconi anemia group C protein activity results in an inability to activate caspase-3 after ionizing radiation.
Fanconi anemia (FA) is a human genetic disease featuring cancer predisposition, genetic instability and DNA damage hypersensitivity. Although abnormalities in DNA repair and cell cycle checkpoint have been proposed as the underlying defect in this syndrome, these hypotheses did not provide full explanations of the complex phenotype. Although not exclusive of such possibilities, alterations in the control of apoptosis might account for the pleiotropic phenotype of this syndrome. We and others have previously reported a deregulation of the apoptotic response to mitomycin C, suggesting that the products of the Fanconi anemia group C protein (FANCC) contribute to the regulation of apoptosis. To explore the functional importance of the apoptotic alterations in FA we analyzed biochemical steps of the execution phase of apoptosis stimulated by another DNA damaging agent, the gamma-ray using FA cell lines derived from complementation group C (FA-C) independent patients. It is shown that the poly(ADP-ribose) polymerase, a target of caspase-3, is not cleaved in FA-C after ionizing radiation (IR). Moreover, caspase-3 is not processed in its active form and, its activity is not increased by IR in FA-C cells compared to normal cells. Altogether, these results demonstrate that loss of the FANCC activity results in a deficiency of the IR-induced apoptosis which is due to an inability to activate caspase-3. Our work suggests that apoptosis signaling induced by mitomycin C and IR is subject to common regulation involving the FANCC protein.
Guillouf
C
C
UMR 218 CNRS, Institut Curie Recherche, Paris, France.
Vit
J P
JP
Rosselli
F
F
D017209:Apoptosis / Q000528:radiation effects; D053148:Caspase 3; D061945:Caspase Inhibitors; D020169:Caspases / Q000378:metabolism* / Q000528:radiation effects; D018797:Cell Cycle Proteins; D016923:Cell Death / Q000528:radiation effects; D002460:Cell Line; D003374:Coumarins / Q000378:metabolism; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D004268:DNA-Binding Proteins; D004789:Enzyme Activation / Q000528:radiation effects; D005199:Fanconi Anemia / Q000235:genetics / Q000378:metabolism* / Q000532:radiotherapy*; D052218:Fanconi Anemia Complementation Group C Protein; D051856:Fanconi Anemia Complementation Group Proteins; D005720:Gamma Rays; D006801:Humans; D009687:Nuclear Proteins; D009842:Oligopeptides / Q000378:metabolism / Q000494:pharmacology; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism / Q000528:radiation effects; D011506:Proteins / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects; D011839:Radiation, Ionizing
D061945:Caspase Inhibitors; D018797:Cell Cycle Proteins; D003374:Coumarins; D015853:Cysteine Proteinase Inhibitors; D004268:DNA-Binding Proteins; C497651:FANCC protein, human; D052218:Fanconi Anemia Complementation Group C Protein; D051856:Fanconi Anemia Complementation Group Proteins; D009687:Nuclear Proteins; D009842:Oligopeptides; D011506:Proteins; C099158:acetyl-aspartyl-glutamyl-valyl-aspartal; C115495:aspartyl-glutamyl-valyl-aspartyl-7-amino-4-trifluoromethylcoumarin; D011065:Poly(ADP-ribose) Polymerases; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases