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- Ferrari, D., et al.
(författare)
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Differential regulation and ATP requirement for caspase-8 and caspase-3 activation during CD95- and anticancer drug-induced apoptosis
- 1998
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Ingår i: Journal of Experimental Medicine. - : Rockefeller University Press. - 0022-1007 .- 1540-9538. ; 188:5, s. 979-984
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Tidskriftsartikel (refereegranskat)abstract
- Apoptosis is induced by different stimuli, among them triggering of the death receptor CD95, staurosporine, and chemotherapeutic drugs. In all cases, apoptosis is mediated by caspases, although it is unclear how these diverse apoptotic stimuli cause protease activation. Two regulatory pathways have been recently identified, but it remains unknown whether they are functionally independent or linked to each other. One is mediated by recruitment of the proximal regulator caspase-8 to the death receptor complex. The other pathway is controlled by the release of cytochrome c from mitochondria and the subsequent ATP-dependent activation of the death regulator apoptotic protease-activating factor 1 (Apaf-1). Here, we report that both pathways can be dissected by depletion of intracellular ATP. Prevention of ATP production completely inhibited caspase activation and apoptosis in response to chemotherapeutic drugs and staurosporine. Interestingly, caspase-8, whose function appeared to be restricted to death receptors, was also activated by these drugs under normal conditions, but not after ATP depletion. In contrast, inhibition of ATP production did not affect caspase activation after triggering of CD95. These results suggest that chemotherapeutic drug-induced caspase activation is entirely controlled by a receptor-independent mitochondrial pathway, whereas CD95-induced apoptosis can be regulated by a separate pathway not requiring Apaf-1 function.
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- Ferrari, D., et al.
(författare)
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P2Z purinoreceptor ligation induces activation of caspases with distinct roles in apoptotic and necrotic alterations of cell death
- 1999
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Ingår i: FEBS Letters. - : Elsevier. - 0014-5793 .- 1873-3468. ; 447:1, s. 71-75
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Tidskriftsartikel (refereegranskat)abstract
- Myeloic cells express a peculiar surface receptor for extracellular ATP, called the P2Z/P2X(7) purinoreceptor, which is involved in cell death signalling. Here, we investigated the role of caspases, a family of proteases implicated in apoptosis and the cytokine secretion. We observed that extracellular ATP induced the activation of multiple caspases including caspase-1, -3 and -8, and subsequent cleavage of the caspase substrates PARP and Iamin B. Using caspase inhibitors, it was found that caspases were specifically involved in ATP-induced apoptotic damage such as chromatin condensation and DNA fragmentation, In contrast, inhibition of caspases only marginally affected necrotic alterations and cell death proceeded normally whether or not nuclear damage was blocked. Our results therefore suggest that the activation of caspases by the P2Z receptor is required for apoptotic but not necrotic alterations of ATP-induced cell death. (C) 1999 Federation of European Biochemical Societies.
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