scholarly journals Apaf-1 and caspase-9 accelerate apoptosis, but do not determine whether factor-deprived or drug-treated cells die

2004 ◽  
Vol 165 (6) ◽  
pp. 835-842 ◽  
Author(s):  
Paul G. Ekert ◽  
Stuart H. Read ◽  
John Silke ◽  
Vanessa S. Marsden ◽  
Hitto Kaufmann ◽  
...  
Keyword(s):  
Cell Death ◽  
Growth Factor ◽  
Cytochrome C ◽  
Programmed Cell Death ◽  
Plasma Membranes ◽  
Mitochondrial Cytochrome ◽  
Caspase 9 ◽  
Cytochrome C Release ◽  
Caspase 2

Apoptosis after growth factor withdrawal or drug treatment is associated with mitochondrial cytochrome c release and activation of Apaf-1 and caspase-9. To determine whether loss of Apaf-1, caspase-2, and caspase-9 prevented death of factor-starved cells, allowing them to proliferate when growth factor was returned, we generated IL-3–dependent myeloid lines from gene-deleted mice. Long after growth factor removal, cells lacking Apaf-1, caspase-9 or both caspase-9 and caspase-2 appeared healthy, retained intact plasma membranes, and did not expose phosphatidylserine. However, release of cytochrome c still occurred, and they failed to form clones when IL-3 was restored. Cells lacking caspase-2 alone had no survival advantage. Therefore, Apaf-1, caspase-2, and caspase-9 are not required for programmed cell death of factor-dependent cells, but merely affect its rate. In contrast, transfection with Bcl-2 provided long-term, clonogenic protection, and could act independently of the apoptosome. Unlike expression of Bcl-2, loss of Apaf-1, caspase-2, or caspase-9 would therefore be unlikely to enhance the survival of cancer cells.

Caspase-dependent cytochrome c release and cell death in chick cardiomyocytes after simulated ischemia-reperfusion

2004 ◽  
Vol 286 (6) ◽  
pp. H2280-H2286 ◽  
Author(s):  
Yimin Qin ◽  
Terry L. Vanden Hoek ◽  
Kim Wojcik ◽  
Travis Anderson ◽  
Chang-Qing Li ◽  
...  
Keyword(s):  
Cell Death ◽  
Cytochrome C ◽  
Ischemia Reperfusion ◽  
Caspase 8 ◽  
Caspase 9 ◽  
Cytochrome C Release ◽  
Simulated Ischemia ◽  
Baseline Levels ◽  
Caspase 2 ◽  
Induced Apoptosis

We recently demonstrated that reperfusion rapidly induces the mitochondrial pathway of apoptosis in chick cardiomyocytes after 1 h of simulated ischemia. Here we tested whether ischemia-reperfusion (I/R)-induced apoptosis could be initiated by caspase-dependent cytochrome c release in this model of cardiomyocyte injury. Fluorometric assays of caspase activity showed little, if any, activation of caspases above baseline levels induced by 1 h of ischemia alone. However, these assays revealed rapid activation of caspase-2, yielding a 2.95 ± 0.52-fold increase (over ischemia only) within the 1st h of reperfusion, whereas activities of caspases-3, -8, and -9 increased only slightly from their baseline levels. The rapid and prominent activation of caspase-2 suggested that it could be an important initiator caspase in this model, and using specific caspase inhibitors given only at the point of reperfusion, we tested this hypothesis. The caspase-2 inhibitor benzyloxycarbonyl-Val-Asp(Ome)-Val-Ala-Asp(Ome)-CH2F was the only caspase inhibitor that significantly inhibited cytochrome c release from mitochondria. This inhibitor also completely blocked activation of caspases-3, -8, and -9. The caspase-3/7 inhibitor transiently and only partially blocked caspase-2 activity and was less effective in blocking the activities of caspases-8 and -9. The caspase-8 inhibitor failed to significantly block caspase-2 or -3, and the caspase-9 inhibitor blocked only caspase-9. Furthermore, the caspase-2 inhibitor protected against I/R-induced cell death, but the caspase-8 inhibitor failed to do so. These data suggest that active caspase-2 initiates cytochrome c release after reperfusion and that it is critical for the I/R-induced apoptosis in this model.

scholarly journals Bcr-Abl-Mediated Protection from Apoptosis Downstream of Mitochondrial Cytochrome c Release

2004 ◽  
Vol 24 (23) ◽  
pp. 10289-10299 ◽  
Author(s):  
Paula B. Deming ◽  
Zachary T. Schafer ◽  
Jessica S. Tashker ◽  
Malia B. Potts ◽  
Mohanish Deshmukh ◽  
...  
Keyword(s):  
Cell Death ◽  
Cytochrome C ◽  
Mitochondrial Cytochrome ◽  
Caspase Activation ◽  
Caspase 9 ◽  
Cytochrome C Release ◽  
Intact Cells ◽  
Caspase Recruitment Domain ◽  
Distinct Mechanism ◽  
Mitochondrial Cytochrome C

ABSTRACT Bcr-Abl, activated in chronic myelogenous leukemias, is a potent cell death inhibitor. Previous reports have shown that Bcr-Abl prevents apoptosis through inhibition of mitochondrial cytochrome c release. We report here that Bcr-Abl also inhibits caspase activation after the release of cytochrome c. Bcr-Abl inhibited caspase activation by cytochrome c added to cell-free lysates and prevented apoptosis when cytochrome c was microinjected into intact cells. Bcr-Abl acted posttranslationally to prevent the cytochrome c-induced binding of Apaf-1 to procaspase 9. Although Bcr-Abl prevented interaction of endogenous Apaf-1 with the recombinant prodomain of caspase 9, it did not affect the association of endogenous caspase 9 with the isolated Apaf-1 caspase recruitment domain (CARD) or Apaf-1 lacking WD-40 repeats. These data suggest that Apaf-1 recruitment of caspase 9 is faulty in the presence of Bcr-Abl and that cytochrome c/dATP-induced exposure of the Apaf-1 CARD is likely defective. These data provide a novel locus of Bcr-Abl antiapoptotic action and suggest a distinct mechanism of apoptosomal inhibition.

scholarly journals VANILLIN EXTRACTED FROM PROSO MILLET AND BARNYARD MILLET INDUCE APOPTOSIS IN HT-29 AND MCF-7 CELL LINE THROUGH MITOCHONDRIA MEDIATED PATHWAY

2017 ◽  
Vol 10 (12) ◽  
pp. 226 ◽  
Author(s):  
Deepa Priya Ramadoss ◽  
Nageswaran Sivalingam
Keyword(s):  
Cell Death ◽  
Cytochrome C ◽  
Apoptotic Cell ◽  
Apoptotic Cell Death ◽  
Caspase 9 ◽  
Cytochrome C Release ◽  
Barnyard Millet ◽  
Proso Millet ◽  
Ht 29 ◽  
Mcf 7

Objective: The main aim of the study was to investigate the bioactive compound vanillin extracted from proso millet (compound 1), and barnyard millet (compound 2) induces apoptotic cell death and whether it is mediated through mitochondrial pathway in HT-29 and MCF-7 cell line.Methods: The cells were treated with 250 μg/ml and 1000 μg/ml concentration of extracted vanillin for 48 hrs. Cytochrome c release and expression level of pro-apoptotic protein Bax and caspase-9 were detected by western blot analysis.Results: The results reveal that extracted compounds increased the release of cytochrome c and upregulating the expression of Bax and caspase-9 as concentration increases in a dose-dependent manner.Conclusion: The study suggests that the vanillin compound extracted from these millets induces apoptotic cell death through a mitochondria-dependent pathway.

Hypoxia induces apoptosis via two independent pathways in Jurkat cells: differential regulation by glucose

2001 ◽  
Vol 281 (5) ◽  
pp. C1596-C1603 ◽  
Author(s):  
Ricky Malhotra ◽  
Zhiwu Lin ◽  
Claudius Vincenz ◽  
Frank C. Brosius
Keyword(s):  
Cell Death ◽  
Cytochrome C ◽  
Glucose Uptake ◽  
Molecular Mechanisms ◽  
Death Receptor ◽  
Jurkat Cells ◽  
Caspase 9 ◽  
Cytochrome C Release ◽  
Extracellular Glucose ◽  
Uptake And Metabolism

Glucose uptake and metabolism inhibit hypoxia-induced apoptosis in a variety of cell types, but the underlying molecular mechanisms remain poorly understood. In the present study, we explore hypoxia-mediated cell death pathways in Jurkat cells in the presence and absence of extracellular glucose. In the absence of extracellular glucose, hypoxia caused cytochrome c release, caspase 3 and poly(ADP-ribose)polymerase cleavage, and DNA fragmentation; this apoptotic response was blocked by the caspase 9 inhibitor z-LEHD-FMK. The presence of extracellular glucose during hypoxia prevented cytochrome c release and activation of caspase 9 but did not prevent apoptosis in Jurkat cells. In these conditions, overexpression of the caspase 8 inhibitor v-FLIP prevented hypoxia-mediated cell death. Thus hypoxia can stimulate two apoptotic pathways in Jurkat cells, one dependent on cytochrome c release from mitochondria that is prevented by glucose uptake and metabolism, and the other independent of cytochrome c release and resulting from activation of the death receptor pathway, which is accelerated by glucose uptake and metabolism.

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