Resistance to CD95/Fas-induced and ceramide-mediated apoptosis of human melanoma cells is caused by a defective mitochondrial cytochrome c release.
Intracellular CD95/Fas-signaling pathways have not been investigated in melanoma yet. Two different CD95 receptor-induced apoptotic pathways are presently known in other cell types: (i) direct activation of caspase-8 and (ii) induction of ceramide-mediated mitochondrial activation, both leading to subsequent caspase-3 activation. In the present study, five of 11 melanoma cell populations were shown to release cytochrome c from mitochondria, which activates caspase-3 and finally results in DNA fragmentation upon treatment with the agonistic monoclonal antibody CH-11. In contrast, this apoptotic pathway was not activated in the remaining six melanoma cell populations. Interestingly, the susceptibility of melanoma cells to CD95L/FasL-triggered cell death was clearly correlated with N-acetylsphingosine-mediated apoptosis. Our results are in line with a defect upstream of mitochondrial cytochrome c release in resistant cells.
Raisova
M
M
Department of Dermatology, University Medical Center Benjamin Franklin, the Free University of Berlin, 12 200, Berlin, Germany.
Bektas
M
M
Wieder
T
T
Daniel
P
P
Eberle
J
J
Orfanos
C E
CE
Geilen
C C
CC
D048868:Adaptor Proteins, Signal Transducing; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D002352:Carrier Proteins / Q000235:genetics; D053148:Caspase 3; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases / Q000235:genetics / Q000378:metabolism; D003574:Cytochrome c Group / Q000378:metabolism*; D053938:DNA Fragmentation / Q000187:drug effects; D019008:Drug Resistance, Neoplasm; D004789:Enzyme Activation / Q000187:drug effects; D053222:Fas Ligand Protein; D053200:Fas-Associated Death Domain Protein; D015870:Gene Expression; D006801:Humans; D006868:Hydrolysis / Q000187:drug effects; D008545:Melanoma / Q000201:enzymology / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D008562:Membrane Glycoproteins / Q000235:genetics; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects; D013109:Sphingomyelins / Q000378:metabolism; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D019014:fas Receptor / Q000235:genetics / Q000276:immunology / Q000502:physiology*
D048868:Adaptor Proteins, Signal Transducing; D000911:Antibodies, Monoclonal; D002352:Carrier Proteins; D003574:Cytochrome c Group; C505533:FADD protein, human; C505661:FASLG protein, human; D053222:Fas Ligand Protein; D053200:Fas-Associated Death Domain Protein; D008562:Membrane Glycoproteins; C064769:N-acetylsphingosine; D012333:RNA, Messenger; D013109:Sphingomyelins; D019014:fas Receptor; C505407:CASP3 protein, human; C505530:CASP8 protein, human; C506433:CASP9 protein, human; D053148:Caspase 3; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases; D013110:Sphingosine