Fanconi anemia type C-deficient hematopoietic cells are resistant to TRAIL (TNF-related apoptosis-inducing ligand)-induced cleavage of pro-caspase-8.
OBJECTIVE
The pathophysiology of bone marrow failure in Fanconi anemia (FA) patients is thought to involve excessive apoptosis involving signaling triggered by fas ligation and tumor necrosis factor (TNF)-alpha, or interferon (IFN)-gamma exposure. We investigated whether a new member of the TNF family, TRAIL (TNF-related apoptosis-inducing ligand), would similarly trigger preferential apoptotic cell death in FA phenotype cells.


METHODS
Hematopoietic cells from FANCC(-/-) transgenic mice and human FA-C lymphoblasts (HSC536N) as well as their phenotypically corrected counterparts (FANCC(+/+), HSC536/FA-Cneo) were compared for their response to apoptosis induction by TRAIL and fas ligation in the presence or absence of IFN-gamma. Cells were also studied for the protein and gene expression of TRAIL-receptors, caspase-8 and its inhibitory protein, FLIP.


RESULTS
TRAIL exposure by itself or in combination with IFN-gamma did not lead to preferential apoptosis induction in human and murine FA-C phenotype hematopoietic cells. This resistance was unrelated to the expression of TRAIL receptors or FLIP isoforms, but correlated with absent cleavage of pro-caspase-8. Results were validated by those from gene expression profiling of relevant genes in the two lymphoblast cell lines.


CONCLUSIONS
TRAIL, in contrast to fas ligation, does not induce preferential apoptosis in FA-C phenotype cells despite shared downstream signaling described in non-FA models. These data provide further insight into the complexity of FA-C-regulated apoptotic signaling.
Platzbecker
Uwe
U
University Hospital Carl Gustav Carus, Dresden, Germany.
Kurre
Peter
P
Guardiola
Philippe
P
Ward
Jessica L
JL
Radich
Jerald P
JP
Kiem
Hans-Peter
HP
Deeg
H Joachim
HJ
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D051017:Apoptosis Regulatory Proteins; D053446:CASP8 and FADD-Like Apoptosis Regulating Protein; D002352:Carrier Proteins / Q000032:analysis; D053181:Caspase 8; D020169:Caspases / Q000378:metabolism*; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D005199:Fanconi Anemia / Q000150:complications / Q000473:pathology*; D052218:Fanconi Anemia Complementation Group C Protein; D051856:Fanconi Anemia Complementation Group Proteins; D020869:Gene Expression Profiling; D006412:Hematopoietic Stem Cells / Q000187:drug effects* / Q000473:pathology; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D008562:Membrane Glycoproteins / Q000494:pharmacology*; D051379:Mice; D009687:Nuclear Proteins; D011506:Proteins / Q000235:genetics / Q000502:physiology*; D015398:Signal Transduction; D053221:TNF-Related Apoptosis-Inducing Ligand; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
D051017:Apoptosis Regulatory Proteins; D053446:CASP8 and FADD-Like Apoptosis Regulating Protein; C506386:CFLAR protein, human; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; C506387:Cflar protein, mouse; D004268:DNA-Binding Proteins; C497651:FANCC protein, human; C497652:Fancc protein, mouse; D052218:Fanconi Anemia Complementation Group C Protein; D051856:Fanconi Anemia Complementation Group Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008562:Membrane Glycoproteins; D009687:Nuclear Proteins; D011506:Proteins; D053221:TNF-Related Apoptosis-Inducing Ligand; C505653:TNFSF10 protein, human; C505654:Tnfsf10 protein, mouse; D014409:Tumor Necrosis Factor-alpha; C505530:CASP8 protein, human; C505526:Casp8 protein, mouse; D053181:Caspase 8; D020169:Caspases