Involvement of protein kinase C-beta and ceramide in tumor necrosis factor-alpha-induced but not Fas-induced apoptosis of human myeloid leukemia cells.
The role of protein kinase C-beta (PKC-beta) in apoptosis induced by tumor necrosis factor (TNF)-alpha and anti-Fas monoclonal antibody (mAb) in the human myeloid HL-60 leukemia cell line was studied by using its variant HL-525, which is deficient in PKC-beta. In contrast to the parental HL-60 cells, HL-525 is resistant to TNF-alpha-induced apoptosis but sensitive to anti-Fas mAb-induced apoptosis. Both cell types expressed similar levels of the TNF-receptor I, whereas the Fas receptor was detected only in HL-525 cells. Transfecting the HL-525 cells with an expression vector containing PKC-beta reestablished their susceptibility to TNF-alpha-induced apoptosis. The apoptotic effect of TNF-alpha in HL-60 and the transfectants was abrogated by fumonisin, an inhibitor of ceramide generation, and by the peptide Ac-YVAD-BoMK, an inhibitor of caspase-1 and -4. Supplementing HL-525 cells with exogenous ceramides bypassed the PKC-beta deficiency and induced apoptosis, which was also restrained by the caspase-1 and -4 inhibitor. The apoptotic effect of anti-Fas mAb in HL-525 cells was abrogated by the antioxidants N-acetylcysteine and glutathione and by the peptide z-DEVD-FMK, an inhibitor of caspase-3 and -7. We suggest that TNF-alpha-induced apoptosis involves PKC-beta and then ceramide and, in turn, caspase-1 and/or -4, whereas anti-Fas mAb-induced apoptosis utilizes reactive oxygen intermediates and, in turn, caspase-3 and/or -7.
Laouar
A
A
Gene Expression and Function Group, Biochip Technology Center, Argonne National Laboratory, Argonne, Illinois 60439-4833, USA.
Glesne
D
D
Huberman
E
E
D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D002518:Ceramides / Q000378:metabolism*; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism*; D007951:Leukemia, Myeloid / Q000473:pathology*; D011493:Protein Kinase C / Q000378:metabolism*; D064546:Protein Kinase C beta; D051381:Rats; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D019014:fas Receptor / Q000276:immunology*
D000911:Antibodies, Monoclonal; D002518:Ceramides; D007527:Isoenzymes; D014409:Tumor Necrosis Factor-alpha; D019014:fas Receptor; D011493:Protein Kinase C; D064546:Protein Kinase C beta