scholarly journals Bcl-2–regulated apoptosis and cytochrome c release can occur independently of both caspase-2 and caspase-9

2004 ◽  
Vol 165 (6) ◽  
pp. 775-780 ◽  
Author(s):  
Vanessa S. Marsden ◽  
Paul G. Ekert ◽  
Mark Van Delft ◽  
David L. Vaux ◽  
Jerry M. Adams ◽  
...  
Keyword(s):  
Cytochrome C ◽  
Embryonic Brain ◽  
Caspase 9 ◽  
Cytochrome C Release ◽  
Hematopoietic Development ◽  
Adult Mice ◽  
Perinatal Lethality ◽  
Caspase 2 ◽  
Apoptosis Initiation ◽  
Redundant Role

Apoptosis in response to developmental cues and stress stimuli is mediated by caspases that are regulated by the Bcl-2 protein family. Although caspases 2 and 9 have each been proposed as the apical caspase in that pathway, neither is indispensable for the apoptosis of leukocytes or fibroblasts. To investigate whether these caspases share a redundant role in apoptosis initiation, we generated caspase-2−/−9−/− mice. Their overt phenotype, embryonic brain malformation and perinatal lethality mirrored that of caspase-9−/− mice but were not exacerbated. Analysis of adult mice reconstituted with caspase-2−/−9−/− hematopoietic cells revealed that the absence of both caspases did not influence hematopoietic development. Furthermore, lymphocytes and fibroblasts lacking both remained sensitive to diverse apoptotic stimuli. Dying caspase-2−/−9−/− lymphocytes displayed multiple hallmarks of caspase-dependent apoptosis, including the release of cytochrome c from mitochondria, and their demise was antagonized by several caspase inhibitors. These findings suggest that caspases other than caspases 2 and 9 can promote cytochrome c release and initiate Bcl-2–regulated apoptosis.

scholarly journals Loss of Caspase-9 Reveals Its Essential Role for Caspase-2 Activation and Mitochondrial Membrane Depolarization

2007 ◽  
Vol 18 (1) ◽  
pp. 84-93 ◽  
Author(s):  
Ajoy K. Samraj ◽  
Dennis Sohn ◽  
Klaus Schulze-Osthoff ◽  
Ingo Schmitz
Keyword(s):  
Cytochrome C ◽  
Anticancer Drugs ◽  
Mitochondrial Membrane ◽  
Genotoxic Stress ◽  
Caspase 9 ◽  
Cytochrome C Release ◽  
Mitochondrial Outer Membrane Permeabilization ◽  
Mitochondrial Membrane Depolarization ◽  
Caspase 2 ◽  
Induced Apoptosis

Caspase-9 plays an important role in apoptosis induced by genotoxic stress. Irradiation and anticancer drugs trigger mitochondrial outer membrane permeabilization, resulting in cytochrome c release and caspase-9 activation. Two highly contentious issues, however, remain: It is unclear whether the loss of the mitochondrial membrane potential ΔΨMcontributes to cytochrome c release and whether caspases are involved. Moreover, an unresolved question is whether caspase-2 functions as an initiator in genotoxic stress-induced apoptosis. In the present study, we have identified a mutant Jurkat T-cell line that is deficient in caspase-9 and resistant to apoptosis. Anticancer drugs, however, could activate proapoptotic Bcl-2 proteins and cytochrome c release, similarly as in caspase-9–proficient cells. Interestingly, despite these alterations, the cells retained ΔΨM. Furthermore, processing and enzyme activity of caspase-2 were not observed in the absence of caspase-9. Reconstitution of caspase-9 expression restored not only apoptosis but also the loss of ΔΨMand caspase-2 activity. Thus, we provide genetic evidence that caspase-9 is indispensable for drug-induced apoptosis in cancer cells. Moreover, loss of ΔΨMcan be functionally separated from cytochrome c release. Caspase-9 is not only required for ΔΨMloss but also for caspase-2 activation, suggesting that these two events are downstream of the apoptosome.

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 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.

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.

LPA protects intestinal epithelial cells from apoptosis by inhibiting the mitochondrial pathway

2003 ◽  
Vol 284 (5) ◽  
pp. G821-G829 ◽  
Author(s):  
Wenlin Deng ◽  
De-An Wang ◽  
Elvira Gosmanova ◽  
Leonard R. Johnson ◽  
Gabor Tigyi
Keyword(s):  
Epithelial Cells ◽  
Cytochrome C ◽  
Protein Expression ◽  
Caspase 3 ◽  
Intestinal Epithelial Cells ◽  
Intestinal Epithelial ◽  
Caspase 9 ◽  
Cytochrome C Release ◽  
Apoptotic Pathway ◽  
Antiapoptotic Activity

We previously showed ( Gastroenterology 123: 206–216, 2002) that lysophosphatidic acid (LPA) protects and rescues rat intestinal epithelial cells (IEC-6) from apoptosis. Here, we provide evidence for the LPA-elicited inhibition of the mitochondrial apoptotic pathway leading to attenuation of caspase-3 activation. Pretreatment of IEC-6 cells with LPA inhibited campothecin-induced caspase-9 and caspase-3 activation and DNA fragmentation. A caspase-9 inhibitor peptide mimicked the LPA-elicited antiapoptotic activity. LPA elicited ERK1/ERK2 and PKB/Akt phosphorylation. The LPA-elicited antiapoptotic activity and inhibition of caspase-9 activity were abrogated by pertussis toxin, PD 98059, wortmannin, and LY 294002. LPA reduced cytochrome c release from mitochondria and prevented activation of caspase-9. LPA prevented translocation of Bax from cytosol to mitochondria and increased the expression of the antiapoptotic Bcl-2 mRNA and protein. LPA had no effect on Bcl-xl, Bad, and Bak mRNA or protein expression. These data indicate that LPA protects IEC-6 cells from camptothecin-induced apoptosis through Gi-coupled inhibition of caspase-3 activation mediated by the attenuation of caspase-9 activation due to diminished cytochrome c release, involving upregulation of Bcl-2 protein expression and prevention of Bax translocation.

JS-K, a Novel Nitric Oxide (NO) Generator, Induces Cytochrome c Release and Caspase Activation in HL-60 Myeloid Leukemia Cells.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 3415-3415
Author(s):  
Paul J. Shami ◽  
Vidya Udupi ◽  
Margaret Yu ◽  
Swati Malaviya ◽  
Joseph E. Saavedra ◽  
...  
Keyword(s):  
Cytochrome C ◽  
Caspase 3 ◽  
Myelogenous Leukemia ◽  
Leukemia Cells ◽  
Caspase 8 ◽  
Caspase 9 ◽  
Cytochrome C Release ◽  
Dose Dependent Fashion ◽  
Acute Myelogenous ◽  
Dose Dependent

Abstract NO induces differentiation and apoptosis in Acute Myelogenous Leukemia (AML) cells. Glutathione S-Transferases (GST) play an important role in multidrug resistance and are upregulated in 90% of AML cells. We have designed a novel prodrug class that releases NO on metabolism by GST. O2-(2,4-Dinitrophenyl) 1-[(4-ethoxycarbonyl)piperazin-1-yl]diazen-1-ium-1,2-diolate (JS-K, a member of this class) has potent antileukemic activity. We have previously shown that JS-K induces apoptosis in HL-60 cells by a caspase dependent mechanism (Molecular Cancer Therapeutics2:409-417,2003). The purpose of this study was to determine the pathway through which JS-K induces apoptosis. Western blot analysis showed that treatment of HL-60 cells with JS-K (0 – 1 μM) for 6 hours results in release of Cytochrome c from mitochondria in a dose dependent fashion. Treatment with JS-K resulted in a dose dependent activation of Caspase 9. Sixteen and 24 hours after exposure to 1 μM JS-K, Caspase 9 activity was induced by 393 ± 93% and 237 ± 13% of control, respectively (p = 0.03 at the 24 hours time point). Treatment with JS-K resulted in a dose dependent activation of Caspase 3. Twenty four hours after exposure to 1 μM JS-K, Caspase 3 activity was 208 ± 3.4 % of control (p = 0.02). Treatment with JS-K also resulted in a dose dependent activation of Caspase 8, but to a lesser extent than Caspase 9 and 3. Twenty four hours after exposure to 1 μM JS-K, Caspase 8 activity was 144 ± 5.3 % of control (p = 0.04). We conclude that JS-K activates the intrinsic pathway of apoptosis in leukemia cells by inducing the release of Cytochrome c from mitochondria. (NO1-CO-12400).

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.

Omi/HtrA2 and XIAP are components of platelet apoptosis signalling

2013 ◽  
Vol 109 (03) ◽  
pp. 532-539 ◽  
Author(s):  
Jeannine Winkler ◽  
Margaret Rand ◽  
Markus Schmugge ◽  
Oliver Speer
Keyword(s):  
Cytochrome C ◽  
Caspase 3 ◽  
Transmembrane Potential ◽  
Signalling Pathway ◽  
Ionophore A23187 ◽  
Caspase 9 ◽  
Cytochrome C Release ◽  
Thrombin Inhibition ◽  
Induction Of Apoptosis ◽  
Apoptotic Proteins

SummaryAlthough platelets possess the hallmarks of apoptosis such as activation of caspases, cytochrome c release and depolarisation of the mitochondrial transmembrane potential (ΔΨm), their entire apoptotic-signalling pathway is not totally understood. Therefore we studied the expression of various apoptotic proteins and found that platelets contain the pro-apoptotic proteins Omi/HtrA2 and Smac/Diablo, as well as their target the X-linked inhibitor of apoptosis XIAP. Omi/HtrA2 and Smac/Diablo were released from mitochondria into the platelet cytosol together with cytochrome c after induction of apoptosis by the Ca2+ ionophore A23187 or the BH3 mimetic ABT-737, and to a lesser extent, after platelet stimulation with collagen and thrombin. Inhibition of Omi/HtrA2 led to decreased levels of activated caspase-3/7 and caspase-9, but did not abolish loss of ΔΨm or prevent release of Omi/HtrA2 from mitochondria. These results indicate that platelets have a functional intrinsic apoptotic-signalling pathway including the pro-apoptotic protease Omi/HtrA2 and its target protein XIAP.

Sign in / Sign up

Export Citation Format

Share Document