Cleavage by Caspase 8 and Mitochondrial Membrane Association Activate the BH3-only Protein Bid during TRAIL-induced Apoptosis

Photodynamic therapy (PDT) is a novel and promising antitumor treatment. Our previous study showed that hydrophilic/lipophilic tetra-α-(4-carboxyphenoxy) phthalocyanine zinc- (TαPcZn-) mediated PDT (TαPcZn-PDT) inhibits the proliferation of human hepatocellular carcinoma Bel-7402 cells by triggering apoptosis and arresting cell cycle. However, mechanisms of TαPcZn-PDT-induced apoptosis of Bel-7402 cells have not been fully clarified. In the present study, therefore, effect of TαPcZn-PDT on apoptosis, P38MAPK, p-P38MAPK, Caspase-8, Caspase-3, Bcl-2, Bid, Cytochrome c, and mitochondria membrane potential in Bel-7402 cells without or with P38MAPK inhibitor SB203580 or Caspase-8 inhibitor Ac-IEFD-CHO was investigated by haematoxylin and eosin (HE) staining assay, flow cytometry analysis of annexin V-FITC/propidium iodide (PI) double staining cells and 5,5′,6,6′-tetrachloro-1,1′,3,3′-tetraethylbenzimidazolylcarbocyanine iodide (JC-1), and immunoblot assay. We found that TαPcZn-PDT resulted in apoptosis induction, activation of P38MAPK, Caspase-8, Caspase-3, and Bid, downregulation of Bcl-2, release of Cytochrome c from mitochondria, and disruption of mitochondrial membrane potential in TαPcZn-PDT-treated Bel-7402 cells. In contrast, SB203580 or Ac-IEFD-CHO attenuated induction of apoptosis, activation of P38MAPK, Caspase-8, Caspase-3, and Bid, downregulation of Bcl-2, release of Cytochrome c from mitochondria, and disruption of mitochondrial membrane potential in TαPcZn-PDT-treated Bel-7402 cells. Taken together, we conclude that Caspase-3, Bcl-2, Bid, and mitochondria are involved in autoregulatory feedback of P38MAPK/Caspase-8 during TαPcZn-PDT-induced apoptosis of Bel-7402 cells.

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MiR-21 regulates the apoptosis of keloid fibroblasts by caspase-8 and the mitochondria-mediated apoptotic signaling pathway via targeting FasL

Biochemistry and Cell Biology ◽

10.1139/bcb-2017-0306 ◽

2018 ◽

Vol 96 (5) ◽

pp. 548-555 ◽

Cited By ~ 8

Author(s):

Ying Liu ◽

Lihong Ren ◽

Wenjing Liu ◽

Zhibo Xiao

Keyword(s):

Signaling Pathway ◽

Mitochondrial Membrane ◽

Caspase 8 ◽

Apoptotic Signaling ◽

Over Expression ◽

Mitochondrial Ros ◽

Proliferation And Apoptosis ◽

Induced Apoptosis ◽

Keloid Fibroblasts

MicroRNA-21 (miR-21) has been found to be upregulated in keloid tissue and to affect the proliferation and apoptosis of keloid fibroblasts; however, the possible mechanisms remain unclear. In this study, we aimed to evaluate the role of miR-21 in FasL-induced caspase-8 activation and the mitochondria-mediated apoptotic signaling pathway in keloid fibroblasts. Our study found that the protein level of FasL was decreased by miR-21 over-expression, while being enhanced by miR-21 inhibition in keloid fibroblasts. Subsequently, the mitochondria-mediated apoptosis of keloid fibroblasts was restrained by miR-21 over-expression, as evidenced by enhanced mitochondrial membrane potential and decreased production of mitochondrial ROS. Moreover, over-expression of miR-21 inhibited the activation of the caspase-8 and the mitochondria-mediated apoptotic signaling pathway. As expected, inhibition of miR-21 had the opposite effects. Finally, silencing of FasL suppressed miR-21 inhibition-induced apoptosis by inactivation of caspase-8 and the mitochondria-mediated apoptotic signaling pathway, which was comparable to Z-IETD-FMK, a caspase-8 inhibitor. Taken together, these results suggest that miR-21 regulates the apoptosis of keloid fibroblasts via targeting FasL, and caspase-8 and the mitochondria-mediated apoptotic signaling pathway is involved in this process. Our findings provide evidence that miR-21 may be considered to be a therapeutic target for keloids.

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N-(1-Pyrenyl) Maleimide Induces Bak Oligomerization and Mitochondrial Dysfunction in Jurkat Cells

BioMed Research International ◽

10.1155/2015/798489 ◽

2015 ◽

Vol 2015 ◽

pp. 1-10 ◽

Cited By ~ 2

Author(s):

Pei-Rong Huang ◽

Shu-Chen Hung ◽

Chia-Chu Pao ◽

Tzu-Chien V. Wang

Keyword(s):

Membrane Potential ◽

Cytochrome C ◽

Cancer Cells ◽

Mitochondrial Membrane ◽

Critical Role ◽

Jurkat Cells ◽

Caspase 8 ◽

Apoptosis Inhibition ◽

Induced Apoptosis ◽

Hematopoietic Cancer

N-(1-pyrenyl) maleimide (NPM) is a fluorescent reagent that is frequently used as a derivatization agent for the detection of thio-containing compounds. NPM has been shown to display a great differential cytotoxicity against hematopoietic cancer cells. In this study, the molecular mechanism by which NPM induces apoptosis was examined. Here, we show that treatment of Jurkat cells with NPM leads to Bak oligomerization, loss of mitochondrial membrane potential (Δψm), and release of cytochrome C from mitochondria to cytosol. Induction of Bak oligomerization appears to play a critical role in NPM-induced apoptosis, as downregulation of Bak by shRNA significantly prevented NPM-induced apoptosis. Inhibition of caspase 8 by Z-IETD-FMK and/or depletion of Bid did not affect NPM-induced oligomerization of Bak. Taken together, these results suggest that NPM-induced apoptosis is mediated through a pathway that is independent of caspase-8 activation.

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Vitamin C inhibits FAS-induced apoptosis in monocytes and U937 cells

Blood ◽

10.1182/blood-2002-11-3559 ◽

2003 ◽

Vol 102 (1) ◽

pp. 336-343 ◽

Cited By ~ 79

Author(s):

Isabel Perez-Cruz ◽

Juan M. Carcamo ◽

David W. Golde

Keyword(s):

Immune System ◽

Vitamin C ◽

Mitochondrial Membrane ◽

Caspase 3 ◽

Fas Ligand ◽

Membrane Integrity ◽

Caspase 8 ◽

Human Monocytes ◽

Fas Receptor ◽

Induced Apoptosis

Abstract The FAS receptor—FAS ligand system is a key apoptotic pathway for cells of the immune system. Ligation of the FAS-receptor (CD95) induces apoptosis by activation of pro—caspase-8 followed by downstream events, including an increase in reactive oxygen species (ROS) and the release of proapoptotic factors from the mitochondria, leading to caspase-3 activation. We investigated the role of vitamin C in FAS-mediated apoptosis and found that intracellular accumulation of pharmacologic concentrations of vitamin C inhibited FAS-induced apoptosis in the monocytic U937 cell line and in fresh human monocytes. Cells were loaded with vitamin C by exposure to dehydroascorbic acid (DHA), thereby circumventing in vitro artifacts associated with the poor transport and pro-oxidant effects of ascorbic acid (AA). Vitamin C inhibition of FAS-mediated apoptosis was associated with reduced activity of caspase-3, -8, and -10, as well as diminished levels of ROS and preservation of mitochondrial membrane integrity. Mechanistic studies indicated that the major effect of vitamin C was inhibition of the activation of caspase-8 with no effect on it enzymatic activity. An independent action of high intracellular concentrations of vitamin C on mitochondrial membrane stabilization was also detected. These studies illuminate the nature of redox-dependent signaling in FAS-induced apoptosis of human monocytes and suggest that vitamin C can modulate the immune system by inhibiting FAS-induced monocyte death. (Blood. 2003;102:336-343)

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Novel Subtilase Cytotoxin Produced by Shiga-Toxigenic Escherichia coli Induces Apoptosis in Vero Cells via Mitochondrial Membrane Damage

Infection and Immunity ◽

10.1128/iai.01510-08 ◽

2009 ◽

Vol 77 (7) ◽

pp. 2919-2924 ◽

Cited By ~ 24

Author(s):

Gen Matsuura ◽

Naoko Morinaga ◽

Kinnosuke Yahiro ◽

Reiko Komine ◽

Joel Moss ◽

...

Keyword(s):

Escherichia Coli ◽

Mitochondrial Membrane ◽

Caspase 3 ◽

Membrane Damage ◽

Annexin V ◽

Vero Cells ◽

Caspase 8 ◽

Caspase Inhibitors ◽

Induced Apoptosis ◽

Subtilase Cytotoxin

ABSTRACT Subtilase cytotoxin (SubAB) is an AB5 cytotoxin produced by some strains of Shiga-toxigenic Escherichia coli. The A subunit is a subtilase-like serine protease and cleaves an endoplasmic reticulum chaperone, BiP, leading to transient inhibition of protein synthesis and cell cycle arrest at G1 phase. Here we show that SubAB, but not the catalytically inactive mutant SubAB(S272A), induced apoptosis in Vero cells, as detected by DNA fragmentation and annexin V binding. SubAB induced activation of caspase-3, -7, and -8. Caspase-3 appeared earlier than caspase-8, and by use of specific caspase inhibitors, it was determined that caspase-3 may be upstream of caspase-8. A general caspase inhibitor blocked SubAB-induced apoptosis, detected by annexin V binding. SubAB also stimulated cytochrome c release from mitochondria, which was not suppressed by caspase inhibitors. In HeLa cells, Apaf-1 small interfering RNA inhibited caspase-3 activation, suggesting that cytochrome c might form an apoptosome, leading to activation of caspase-3. These data suggested that SubAB induced caspase-dependent apoptosis in Vero cells through mitochondrial membrane damage.

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CDDO induces apoptosis via the intrinsic pathway in lymphoid cells.

10.31234/osf.io/n462r ◽

2020 ◽

Author(s):

Lungwani Muungo

Keyword(s):

Mitochondrial Membrane ◽

Lymphoid Cells ◽

Jurkat Cells ◽

Caspase 8 ◽

Peroxisome Proliferator ◽

Caspase Inhibitor ◽

Intrinsic Pathway ◽

Caspase 9 ◽

Peroxisome Proliferator Activated Receptor ◽

Induced Apoptosis

The peroxisome-proliferator-activated receptor (PPAR) c agonist,CDDO, is under investigation for use in various malignancies.The mechanisms by which CDDO induces apoptosisare controversial. We have therefore sought to determine thesemechanisms using primary chronic lymphocyte leukemic (CLL)cells and Jurkat cell lines with defined apoptotic abnormalities.In these cells, CDDO induced-apoptosis involved caspaseindependentloss in mitochondrial membrane potential followedby caspase processing. The pattern of CDDO-inducedcaspase processing, defined by use of a caspase inhibitor,strongly suggested that caspase-9 was the apical caspase.Moreover, CDDO induced apoptosis in caspase-8 and FADDdeficientbut not in Bcl-xL overexpressing Jurkat cells. In CLLcells, CDDO induced an early release of mitochondrial cytochromec and Smac that preceded apoptosis. Thus, in both celltypes, CDDO induced apoptosis primarily by the intrinsicpathway with caspase-9 as the apical caspase. This hasimportant implications in the design of novel agents for thetreatment of CLL and other malignancies.

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