Sensitization for γ-Irradiation-Induced Apoptosis by Smac.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 3392-3392
Author(s):  
Stavros Giagkousiklidis ◽  
Hubert Kasperczyk ◽  
Meike Vogler ◽  
Klaus-Michael Debatin ◽  
Simone Fulda
Keyword(s):  
Cell Death ◽  
Tumor Cell ◽  
Membrane Damage ◽  
Neuroblastoma Cells ◽  
Cellular Stress Response ◽  
Caspase Inhibitor ◽  
Cytochrome C Release ◽  
Γ Irradiation ◽  
Induced Apoptosis ◽  
First Time

Abstract Smac is released from mitochondria during the onset of apoptosis and promotes apoptosis via abrogating the binding of Inhibitor of Apoptosis Proteins (IAPs) to caspases. γ-irradiation is one of the most commonly used therapeutic approaches in clinical oncology, which triggers cell death in tumors via DNA and/or membrane damage. Since we recently found that Smac agonists sensitized even resistant tumors for apoptosis induced by death receptor ligation or anticancer drugs, we investigated the effect of Smac agonists on apoptosis following γ-irradiation in the present study. Here, we report for the first time that overexpression of mitochondrial or cytosolic Smac significantly increased radiosensitivity of various cancers. Transfection-enforced expression of Smac strongly enhanced apoptosis upon γ-irradiation in SH-EP neuroblastoma cells, which were resistant to g-irradiation in the absence of Smac. Importantly, Smac overexpression also reduced clonogenic tumor cell survival following γ-irradiation. Analysis of signaling pathways revealed that overexpression of Smac resulted in more rapid and more potent activation of caspase pathways, e.g caspase-2, -3,- 8, -9. The broad range caspase inhibitor zVAD.fmk abrogated apoptosis upon γ-irradiation indicating that apoptosis was mediated by caspases. In addition, overexpression of Smac promoted loss of mitochondrial membrane potential and cytochrome c release upon γ-irradiation. Interestingly, γ-irradiation-induced mitochondrial perturbations were blocked in the presence of the caspase inhibitor zVAD.fmk suggesting that caspase activity was required for mitochondrial alterations in response to γ-irradiation. Notably, cell cycle alterations and activation of NF-κB occured in a similar manner in vector control and Smac-transfected cells suggesting that Smac did not significantly alter the initial cellular stress response upon γ-irradiation. Importantly, Smac overexpression sensitized various tumor cell lines for γ-irradiation-induced apoptosis, indicating that the sensitization effect of Smac for γ-irradiation was not restricted to a particular cell type. By demonstrating that Smac can sensitize various tumor cells towards γ-irradiation-induced cell death, our findings provide for the first time evidence that Smac agonists may be a useful tool to enhance radiosensitivity in a variety of human cancers.

scholarly journals Ginkgo biloba Prevents Oxidative Stress-Induced Apoptosis Blocking p53 Activation in Neuroblastoma Cells

Antioxidants ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 279 ◽  
Author(s):  
Francesco Di Meo ◽  
Rossana Cuciniello ◽  
Sabrina Margarucci ◽  
Paolo Bergamo ◽  
Orsolina Petillo ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Death ◽  
Neurodegenerative Diseases ◽  
Ginkgo Biloba ◽  
Apoptotic Cell ◽  
Neuroblastoma Cells ◽  
Apoptotic Cell Death ◽  
Parp Cleavage ◽  
Egb 761 ◽  
Induced Apoptosis

Oxidative stress has been associated to neuronal cell loss in neurodegenerative diseases. Neurons are post-mitotic cells that are very sensitive to oxidative stress—especially considering their limited capacity to be replaced. Therefore, reduction of oxidative stress, and inhibiting apoptosis, will potentially prevent neurodegeneration. In this study, we investigated the neuroprotective effect of Ginkgo biloba extract (EGb 761) against H2O2 induced apoptosis in SK-N-BE neuroblastoma cells. We analysed the molecular signalling pathway involved in the apoptotic cell death. H2O2 induced an increased acetylation of p53 lysine 382, a reduction in mitochondrial membrane potential, an increased BAX/Bcl-2 ratio and consequently increased Poly (ADP-ribose) polymerase (PARP) cleavage. All these effects were blocked by EGb 761 treatment. Thus, EGb 761, acting as intracellular antioxidant, protects neuroblastoma cells against activation of p53 mediated pathway and intrinsic mitochondrial apoptosis. Our results suggest that EGb 761, protecting against oxidative-stress induced apoptotic cell death, could potentially be used as nutraceutical for the prevention and treatment of neurodegenerative diseases.

scholarly journals Naja atra Cardiotoxin 3 Elicits Autophagy and Apoptosis in U937 Human Leukemia Cells through the Ca2+/PP2A/AMPK Axis

Toxins ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 527 ◽  
Author(s):  
Jing-Ting Chiou ◽  
Yi-Jun Shi ◽  
Liang-Jun Wang ◽  
Chia-Hui Huang ◽  
Yuan-Chin Lee ◽  
...  
Keyword(s):  
Cell Death ◽  
Membrane Damage ◽  
Leukemia Cells ◽  
Human Leukemia ◽  
U937 Cells ◽  
Cell Membrane Damage ◽  
Human Leukemia Cells ◽  
Phosphatase 2A ◽  
Induced Apoptosis ◽  
Naja Atra

Cardiotoxins (CTXs) are suggested to exert their cytotoxicity through cell membrane damage. Other studies show that penetration of CTXs into cells elicits mitochondrial fragmentation or lysosome disruption, leading to cell death. Considering the role of AMPK-activated protein kinase (AMPK) in mitochondrial biogenesis and lysosomal biogenesis, we aimed to investigate whether the AMPK-mediated pathway modulated Naja atra (Taiwan cobra) CTX3 cytotoxicity in U937 human leukemia cells. Our results showed that CTX3 induced autophagy and apoptosis in U937 cells, whereas autophagic inhibitors suppressed CTX3-induced apoptosis. CTX3 treatment elicited Ca2+-dependent degradation of the protein phosphatase 2A (PP2A) catalytic subunit (PP2Acα) and phosphorylation of AMPKα. Overexpression of PP2Acα mitigated the CTX3-induced AMPKα phosphorylation. CTX3-induced autophagy was via AMPK-mediated suppression of the Akt/mTOR pathway. Removal of Ca2+ or suppression of AMPKα phosphorylation inhibited the CTX3-induced cell death. CTX3 was unable to induce autophagy and apoptosis in U937 cells expressing constitutively active Akt. Met-modified CTX3 retained its membrane-perturbing activity, however, it did not induce AMPK activation and death of U937 cells. These results conclusively indicate that CTX3 induces autophagy and apoptosis in U937 cells via the Ca2+/PP2A/AMPK axis, and suggest that the membrane-perturbing activity of CTX3 is not crucial for the cell death signaling pathway induction.

Honokiol Induces Autophagic Apoptosis in Neuroblastoma Cells through a P53-Dependent Pathway

2019 ◽  
Vol 47 (04) ◽  
pp. 895-912 ◽  
Author(s):  
Ming-Chung Lin ◽  
Yuan-Wen Lee ◽  
Yuan-Yun Tseng ◽  
Yung-Wei Lin ◽  
Jui-Tai Chen ◽  
...  
Keyword(s):  
Dna Damage ◽  
Cell Death ◽  
Cell Apoptosis ◽  
Caspase 3 ◽  
Therapeutic Option ◽  
Neuroblastoma Cells ◽  
Cytochrome C Release ◽  
Dependent Pathway ◽  
Dependent Mechanism ◽  
Stimulation Of

In children, neuroblastomas are the most common and deadly solid tumor. Our previous studies showed that honokiol can cross the blood–brain barrier and kill neuroblastoma cells. In this study, we further evaluated if exposure to honokiol for short periods could induce autophagy and subsequent apoptosis of neuroblastoma cells and possible mechanisms. Exposure of neuroblastoma neuro-2a cells to honokiol for 24[Formula: see text]h induced morphological shrinkage and cell death. As to the mechanisms, honokiol consecutively induced cytochrome c release from mitochondria, caspase-3 activation, DNA fragmentation and cell apoptosis. Separately, honokiol time-dependently augmented the proportion of autophagic cells and the ratio of light chain 3 (LC3)-II/LC3-I. Pretreatment of neuro-2a cells with 3-methyladenine, an inhibitor of autophagy, attenuated honokiol-induced cell autophagy, caspase-3 activation, DNA damage and cell apoptosis. In contrast, stimulation of autophagy by rapamycin, an inducer of autophagy, significantly enhanced honokiol-induced cell apoptosis. Furthermore, honokiol-induced autophagic apoptosis was confirmed in neuroblastoma NB41A3 cells. Knocking down translation of p53 using RNA interference attenuated honokiol-induced autophagy and apoptosis in neuro-2a and NB41A3 cells. Taken together, this study showed that at early periods, honokiol can induce autophagic apoptosis of neuroblastoma cells through activating a p53-dependent mechanism. Consequently, honokiol has the potential to be a therapeutic option for neuroblastomas.

scholarly journals BH3-only Protein Noxa Is a Mediator of Hypoxic Cell Death Induced by Hypoxia-inducible Factor 1α

2003 ◽  
Vol 199 (1) ◽  
pp. 113-124 ◽  
Author(s):  
Jee-Youn Kim ◽  
Hyun-Jong Ahn ◽  
Jong-Hoon Ryu ◽  
Kyoungho Suk ◽  
Jae-Hoon Park
Keyword(s):  
Cell Death ◽  
Hypoxia Inducible Factor ◽  
Subtractive Hybridization ◽  
Hypoxic Cell ◽  
Cytochrome C Release ◽  
Degenerative Disorders ◽  
Family Protein ◽  
Polymerase Chain ◽  
Induced Apoptosis ◽  
Candidate Molecule

Hypoxia is a common cause of cell death and is implicated in many disease processes including stroke and chronic degenerative disorders. In response to hypoxia, cells express a variety of genes, which allow adaptation to altered metabolic demands, decreased oxygen demands, and the removal of irreversibly damaged cells. Using polymerase chain reaction–based suppression subtractive hybridization to find genes that are differentially expressed in hypoxia, we identified the BH3-only Bcl-2 family protein Noxa. Noxa is a candidate molecule mediating p53-induced apoptosis. We show that Noxa promoter responds directly to hypoxia via hypoxia-inducible factor (HIF)-1α. Suppression of Noxa expression by antisense oligonucleotides rescued cells from hypoxia-induced cell death and decreased infarction volumes in an animal model of ischemia. Further, we show that reactive oxygen species and resultant cytochrome c release participate in Noxa-mediated hypoxic cell death. Altogether, our results show that Noxa is induced by HIF-1α and mediates hypoxic cell death.

scholarly journals High-Dialysate-Glucose-Induced Oxidative Stress and Mitochondrial-Mediated Apoptosis in Human Peritoneal Mesothelial Cells

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Kuan-Yu Hung ◽  
Shin-Yun Liu ◽  
Te-Cheng Yang ◽  
Tien-Ling Liao ◽  
Shu-Huei Kao
Keyword(s):  
Cell Death ◽  
Mitochondrial Dysfunction ◽  
Mesothelial Cells ◽  
Cytochrome C Release ◽  
Dialysis Adequacy ◽  
Peritoneal Mesothelial Cells ◽  
Functional Changes ◽  
Key Factor ◽  
Human Peritoneal Mesothelial Cells ◽  
Induced Apoptosis

Human peritoneal mesothelial cells (HPMCs) are a critical component of the peritoneal membrane and play a pivotal role in dialysis adequacy. Loss of HPMCs can contribute to complications in peritoneal dialysis. Compelling evidence has shown that high-dialysate glucose is a key factor causing functional changes and cell death in HPMCs. We investigated the mechanism of HPMC apoptosis induced by high-dialysate glucose, particularly the role of mitochondria in the maintenance of HPMCs. HPMCs were incubated at glucose concentrations of 5 mM, 84 mM, 138 mM, and 236 mM. Additionally, N-acetylcysteine (NAC) was used as an antioxidant to clarify the mechanism of high-dialysate-glucose-induced apoptosis. Exposing HPMCs to high-dialysate glucose resulted in substantial apoptosis with cytochrome c release, followed by caspase activation and poly(ADP-ribose) polymerase cleavage. High-dialysate glucose induced excessive reactive oxygen species production and lipid peroxidation as well as oxidative damage to DNA. Mitochondrial fragmentation, multiple mitochondrial DNA deletions, and dissipation of the mitochondrial membrane potential were also observed. The mitochondrial dysfunction and cell death were suppressed using NAC. These results indicated that mitochondrial dysfunction is one of the main causes of high-dialysate-glucose-induced HPMC apoptosis.

z-VAD-fmk augmentation of TNFα-stimulated neutrophil apoptosis is compound specific and does not involve the generation of reactive oxygen species

Blood ◽  
2005 ◽  
Vol 105 (7) ◽  
pp. 2970-2972 ◽  
Author(s):  
Andrew S. Cowburn ◽  
Jessica F. White ◽  
John Deighton ◽  
Sarah R. Walmsley ◽  
Edwin R. Chilvers
Keyword(s):  
Reactive Oxygen Species ◽  
Cell Death ◽  
Broad Spectrum ◽  
Reactive Oxygen ◽  
Cell Types ◽  
Ros Generation ◽  
Neutrophil Apoptosis ◽  
Oxygen Species ◽  
Caspase Inhibitor ◽  
Induced Apoptosis

Abstract In most cell types constitutive and ligand-induced apoptosis is a caspase-dependent process. In neutrophils, however, the broad-spectrum caspase inhibitor z-VAD-fmk enhances tumor necrosis factor-α (TNFα)-induced cell death, and this has been interpreted as evidence for caspase-dependent and -independent cell death pathways. Our aim was to determine the specificity of the effect of z-VAD-fmk in neutrophils and define the potential mechanism of action. While confirming that z-VAD-fmk (> 100 μM) enhances TNFα-induced neutrophil apoptosis, lower concentrations (1-30 μM) completely blocked TNFα-stimulated apoptosis. Boc-D-fmk, a similar broad-spectrum caspase inhibitor, and z-IETD-fmk, a selective caspase-8 inhibitor, caused a concentration-dependent inhibition of only TNFα-stimulated apoptosis. Moreover, the caspase-9 inhibitor, Ac-LEHD-cmk, had no effect on TNFα-induced apoptosis, and z-VAD-fmk and Boc-D-fmk inhibited TNFα-stimulated reactive oxygen species (ROS) generation. These data suggest that TNFα-induced apoptosis in neutrophils is fully caspase dependent and uses a mitochondrial-independent pathway and that the proapoptotic effects of z-VAD-fmk are compound specific and ROS independent.

scholarly journals Triptolide induces caspase-dependent cell death mediated via the mitochondrial pathway in leukemic cells

Blood ◽  
2006 ◽  
Vol 108 (2) ◽  
pp. 630-637 ◽  
Author(s):  
Bing Z. Carter ◽  
Duncan H. Mak ◽  
Wendy D. Schober ◽  
Teresa McQueen ◽  
David Harris ◽  
...  
Keyword(s):  
Cell Death ◽  
Anticancer Agents ◽  
Chinese Herb ◽  
Mitochondrial Pathway ◽  
Leukemic Cells ◽  
Cytochrome C Release ◽  
Knock Out ◽  
Dependent Cell ◽  
Induced Apoptosis

Triptolide, a diterpenoid isolated from the Chinese herb Tripterygium wilfordii Hook.f, has shown antitumor activities in a broad range of solid tumors. Here, we examined its effects on leukemic cells and found that, at 100 nM or less, it potently induced apoptosis in various leukemic cell lines and primary acute myeloid leukemia (AML) blasts. We then attempted to identify its mechanisms of action. Triptolide induced caspase-dependent cell death accompanied by a significant decrease in XIAP levels. Forced XIAP overexpression attenuated triptolide-induced cell death. Triptolide also decreased Mcl-1 but not Bcl-2 and Bcl-XL levels. Bcl-2 overexpression suppressed triptolide-induced apoptosis. Further, triptolide induced loss of the mitochondrial membrane potential and cytochrome C release. Caspase-9 knock-out cells were resistant, while caspase-8–deficient cells were sensitive to triptolide, suggesting criticality of the mitochondrial but not the death receptor pathway for triptolide-induced apoptosis. Triptolide also enhanced cell death induced by other anticancer agents. Collectively, our results demonstrate that triptolide decreases XIAP and potently induces caspase-dependent apoptosis in leukemic cells mediated through the mitochondrial pathway at low nanomolar concentrations. The potent antileukemic activity of triptolide in vitro warrants further investigation of this compound for the treatment of leukemias and other malignancies.

Ibuprofen-induced Walker 256 tumor cell death: cytochrome c release from functional mitochondria and enhancement by calcineurin inhibition

2004 ◽  
Vol 68 (11) ◽  
pp. 2197-2206 ◽  
Author(s):  
Claudia B.L. Campos ◽  
Giovanna R. Degasperi ◽  
Denise S. Pacífico ◽  
Luciane C. Alberici ◽  
Raquel S. Carreira ◽  
...  
Keyword(s):  
Cell Death ◽  
Cytochrome C ◽  
Tumor Cell ◽  
Tumor Cell Death ◽  
Cytochrome C Release ◽  
Walker 256 ◽  
Calcineurin Inhibition ◽  
Walker 256 Tumor

Abstract 1950: Role of Superoxide, Nitric Oxide and Peroxynitrite in Doxorubicin-induced Cell Death in vitro and in vivo

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Partha Mukhopadhyay ◽  
Mohanraj Rajesh ◽  
Sandor Bátkai ◽  
György Haskó ◽  
Csaba Szabo ◽  
...  
Keyword(s):  
Cell Death ◽  
Caspase 3 ◽  
Superoxide Generation ◽  
Cytochrome C Release ◽  
Mitochondrial Superoxide ◽  
Induced Apoptosis ◽  
Peroxynitrite Scavengers

Although doxorubicin (DOX) is one of the most potent antitumor agents available, its clinical use is limited because of the risk of severe cardiotoxicity often leading to irreversible congestive heart failure. Apoptotic cell death is a key component in DOX-induced cardiotoxicity, but its trigger(s) and mechanisms are poorly understood. Here, we explore the role of peroxynitrite (a reactive oxidant produced from the diffusion-controlled reaction between nitric oxide and superoxide anion) in DOX-induced cell death. Using a well-established in vivo mouse model of DOX-induced acute heart failure, we demonstrate marked increases in myocardial apoptosis (caspase-3 and 9 gene expression, caspase 3 activity, cytochrome-c release, and TUNEL), iNOS but not eNOS and nNOS expression, 3-nitrotyrosine formation and a decrease in myocardial contractility following DOX treatment. Pre-treatment of mice with peroxynitrite scavengers markedly attenuated DOX-induced myocardial cell death and dysfunction without affecting iNOS expression. DOX induced increased superoxide generation and nitrotyrosine formation in the mitochondria, dissipation of mitochondrial membrane potential, apoptosis (cytochrome-C release, annexin V staining, caspase activation, nuclear fragmentation), and disruption of actin cytoskeleton structure in cardiac-derived H9c2 cells. Selective iNOS inhibitors attenuated DOX-induced apoptosis, without affecting increased mitochondrial superoxide generation, whereas NO donors increased DOX-induced cell death in vitro . The peroxynitrite scavengers FeTMPyP and MnTMPyP markedly reduced both DOX- or peroxynitrite-induced nitrotyrosine formation and cell death in vitro , without affecting DOX-induced increased mitochondrial superoxide formation. Thus, peroxynitrite is a major trigger of DOX-induced apoptosis, and its effective neutralization can be of significant therapeutic benefit.

Radiosensitization of Human Cancers by Smac Agonists.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 1523-1523
Author(s):  
Stavros Giagkousiklidis ◽  
Meike Vogler ◽  
Andrew Westhoff ◽  
Hubert Kasperczyk ◽  
Klaus-Michael Debatin ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Control Point ◽  
Clonogenic Survival ◽  
Cellular Stress Response ◽  
Cytochrome C Release ◽  
Γ Irradiation ◽  
Human Cancers ◽  
Caspase 2

Abstract Resistance to current treatment regimens such as radiation therapy remains a major concern in oncology and may be caused by defects in apoptosis programs. Since “Inhibitor of apoptosis proteins” (IAPs), which are expressed at high levels in many tumors, block apoptosis at the core of the apoptotic machinery by inhibiting caspases, therapeutic modulation of IAPs could target a key control point in resistance. Here, we report for the first time that full length or mature Smac, an inhibitor of IAPs, significantly enhanced γ-irradiation-induced apoptosis and reduced clonogenic survival in neuroblastoma, glioblastoma or pancreatic carcinoma cells. Notably, Smac had no impact on DNA damage/DNA repair, activation of NF-κB, upregulation of p53 and p21 proteins or cell cycle arrest following γ-irradiation indicating that Smac did not alter the initial damage and/or cellular stress response. Smac enhanced activation of caspase-2, -3, -8 and -9, loss of mitochondrial membrane potential and cytochrome c release upon γ-irradiation. Inhibition of caspases also blocked γ-irradiation-induced mitochondrial perturbations, indicating that Smac facilitated caspase activation, which in turn triggered a mitochondrial amplification loop. Interestingly, mitochondrial perturbations were completely blocked by the broad range caspase inhibitor zVAD.fmk or the relatively selective caspase-2 inhibitor zVDVAD.fmk, whereas caspase-8 or caspase-3 inhibitors only inhibited the increased drop of mitochondrial membrane potential provided by Smac, suggesting that caspase-2 was acting upstream of mitochondria upon γ-irradiation. In conclusion, our findings provide evidence that targeting IAPs, e.g. by Smac agonists, is a promising strategy to enhance radiosensitivity in human cancers.

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