Caspase-independent cell death induced by anti-CD2 or staurosporine in activated human peripheral T lymphocytes.
We examined the effects of the cell-permeable, broad spectrum peptide caspase inhibitors, benzyloxycarbonyl-Val-Ala-Asp(OMe)-fluoromethyl ketone (Z-VAD.fmk), and BOC-Asp(OMe)-fluoromethyl ketone (BOC-D.fmk), on apoptosis induced by anti-CD2, anti-Fas, and the protein kinase inhibitor staurosporine in activated human peripheral T lymphocytes. We monitored ultrastructural, flow cytometric, and biochemical apoptotic changes, including externalization of phosphatidylserine, cleavage of poly(ADP-ribose) polymerase (PARP) and lamins, activation of caspase-3 and caspase-7, decrease in mitochondrial membrane potential, and DNA fragmentation. Z-VAD.fmk and BOC-D.fmk completely inhibited all the biochemical and ultrastructural changes of apoptosis in anti-Fas-treated cells. In marked contrast, neither Z-VAD.fmk nor BOC-D.fmk inhibited CD2- or staurosporine-mediated cell shrinkage, dilatation of the endoplasmic reticulum (seen in anti-CD2-treated cells), externalization of phosphatidylserine, and loss of mitochondrial membrane potential that accompanied cell death. However, these inhibitors did inhibit the cleavage of PARP and lamins and the formation of hypodiploid cells, and partially inhibited chromatin condensation. These results demonstrate that in activated T cells, anti-CD2 and staurosporine induce a caspase-independent cell death pathway that exhibits prominent cytoplasmic features of apoptosis. However, caspase activation is required for the proteolytic degradation of nuclear substrates such as PARP and lamins together with the DNA fragmentation and extreme chromatin condensation that occur in apoptotic cells.
Centre National de la Recherche Scientifique, Unité Propre de Recherche (UPR) 420, Villejuif, France.
O
O
Déas
C
C
Dumont
M
M
MacFarlane
M
M
Rouleau
C
C
Hebib
F
F
Harper
F
F
Hirsch
B
B
Charpentier
G M
GM
Cohen
A
A
Senik
D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D000911:Antibodies, Monoclonal / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects / Q000276:immunology*; D018801:CD2 Antigens / Q000187:drug effects / Q000276:immunology*; D053143:Caspase 2; D053148:Caspase 3; D053179:Caspase 7; D020169:Caspases; D016923:Cell Death / Q000187:drug effects / Q000276:immunology; D003546:Cysteine Endopeptidases / Q000378:metabolism / Q000502:physiology*; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D004171:Diploidy; D004789:Enzyme Activation / Q000187:drug effects / Q000276:immunology; D006801:Humans; D006868:Hydrolysis / Q000187:drug effects; D034882:Lamins; D008213:Lymphocyte Activation / Q000187:drug effects; D009687:Nuclear Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D011506:Proteins / Q000378:metabolism; D019311:Staurosporine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D016176:T-Lymphocyte Subsets / Q000187:drug effects / Q000201:enzymology / Q000276:immunology* / Q000648:ultrastructure; D019014:fas Receptor / Q000187:drug effects / Q000276:immunology / Q000502:physiology
D000590:Amino Acid Chloromethyl Ketones; D000911:Antibodies, Monoclonal; D018801:CD2 Antigens; D015853:Cysteine Proteinase Inhibitors; D034882:Lamins; D009687:Nuclear Proteins; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D011506:Proteins; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; C103192:butyloxycarbonyl-O-methyl-aspartyl-fluoromethyl ketone; D019014:fas Receptor; D011065:Poly(ADP-ribose) Polymerases; C505407:CASP3 protein, human; C505520:CASP7 protein, human; D053143:Caspase 2; D053148:Caspase 3; D053179:Caspase 7; D020169:Caspases; D003546:Cysteine Endopeptidases; D019311:Staurosporine