scholarly journals Cystine and Methionine Deficiency Promotes Ferroptosis by Inducing B-Cell Translocation Gene 1

Antioxidants ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1543
Author(s):  
Il-Je Cho ◽  
Doyeon Kim ◽  
Eun-Ok Kim ◽  
Kyung-Hwan Jegal ◽  
Jae-Kwang Kim ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Lipid Peroxidation ◽  
Cell Death ◽  
Transcription Factor ◽  
Stress Response ◽  
B Cell ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Integrated Stress Response ◽  
Methionine Deficiency

Ferroptosis is a type of programmed necrosis triggered by iron-dependent lipid peroxidation. We investigated the role of B-cell translocation gene 1 (BTG1) in cystine and methionine deficiency (CST/Met (–))-mediated cell death. CST/Met (–) depleted reduced and oxidized glutathione in hepatocyte-derived cells, increased prostaglandin-endoperoxide synthase 2 expression, and promoted reactive oxygen species accumulation and lipid peroxidation, as well as necrotic cell death. CST/Met (–)-mediated cell death and lipid peroxidation was specifically inhibited by pretreatment with ferroptosis inhibitors. In parallel with cell death, CST/Met (–) blocked global protein translation and increased the expression of genes associated with the integrated stress response. Moreover, CST/Met (–) significantly induced BTG1 expression. Using a BTG1 promoter-harboring reporter gene and siRNA, activating transcription factor 4 (ATF4) was identified as an essential transcription factor for CST/Met (–)-mediated BTG1 induction. Although knockout of BTG1 in human HAP1 cells did not affect the accumulation of reactive oxygen species induced by CST/Met (–), BTG1 knockout significantly decreased the induction of genes associated with the integrated stress response, and reduced lipid peroxidation and cell death in response to CST/Met (–). The results demonstrate that CST/Met (–) induces ferroptosis by activating ATF4-dependent BTG1 induction.

Complement-mediated cell death induced by rituximab in B-cell lymphoproliferative disorders is mediated in vitro by a caspase-independent mechanism involving the generation of reactive oxygen species

Blood ◽  
2001 ◽  
Vol 98 (9) ◽  
pp. 2771-2777 ◽  
Author(s):  
Beatriz Bellosillo ◽  
Neus Villamor ◽  
Armando López-Guillermo ◽  
Silvia Marcé ◽  
Jordi Esteve ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Cell Death ◽  
B Cell ◽  
Cytotoxic Effect ◽  
Reactive Oxygen ◽  
Lymphoproliferative Disorders ◽  
Oxygen Species ◽  
Independent Mechanism ◽  
In Cells

Abstract Mechanisms involving the in vitro effect of rituximab in cells from 55 patients with B-cell lymphoproliferative disorders were investigated. No cytotoxic effect was observed when cells were incubated with rituximab alone, but in the presence of human AB serum rituximab induced complement-dependent cell death (R-CDC). A cytotoxic effect was observed in cells from 9 of 33 patients with B-cell chronic lymphocytic leukemia, 16 of 16 patients with mantle-cell lymphoma, 4 of 4 patients with follicular lymphoma, and 2 of 2 patients with hairy-cell leukemia. R-CDC was observed in cells from patients expressing more than 50 × 103 CD20 molecules per cell, and directly correlated with the number of CD20 molecules per cell. Preincubation with anti-CD59 increased the cytotoxic effect of rituximab and sensitized cells from nonsensitive cases. Neither cleavage of poly-ADP ribose polymerase (PARP) nor activation of caspase-3 was observed in R-CDC. In addition, no cells with a hypodiploid DNA content were detected and R-CDC was not prevented by a broad-spectrum caspase inhibitor, suggesting a caspase-independent mechanism. Incubation with rituximab in the presence of AB serum induced a rapid and intense production of reactive oxygen species (ROS). R-CDC was blocked by the incubation of cells with N-acetyl-L-cysteine (NAC) or Tiron, 2 ROS scavengers, indicating that the cytotoxic effect was due to the generation of superoxide (O2−) radicals. In conclusion, the results of the present study suggest that CD20, CD59, and complement have a role in the in vitro cytotoxic effect of rituximab, which is mediated by a caspase-independent process that involves ROS generation.

scholarly journals Ribosomal Elongation Factor 4 Promotes Cell Death Associated with Lethal Stress

mBio ◽  
2014 ◽  
Vol 5 (6) ◽  
Author(s):  
Liping Li ◽  
Yuzhi Hong ◽  
Gan Luan ◽  
Michael Mosel ◽  
Muhammad Malik ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Cell Death ◽  
Stress Response ◽  
Elongation Factor ◽  
Reactive Oxygen ◽  
Anaerobic Growth ◽  
Mild Stress ◽  
Oxygen Species ◽  
Severe Stress ◽  
Moderate Stress

ABSTRACT Ribosomal elongation factor 4 (EF4) is highly conserved among bacteria, mitochondria, and chloroplasts. However, the EF4-encoding gene, lepA, is nonessential and its deficiency shows no growth or fitness defect. In purified systems, EF4 back-translocates stalled, posttranslational ribosomes for efficient protein synthesis; consequently, EF4 has a protective role during moderate stress. We were surprised to find that EF4 also has a detrimental role during severe stress: deletion of lepA increased Escherichia coli survival following treatment with several antimicrobials. EF4 contributed to stress-mediated lethality through reactive oxygen species (ROS) because (i) the protective effect of a ΔlepA mutation against lethal antimicrobials was eliminated by anaerobic growth or by agents that block hydroxyl radical accumulation and (ii) the ΔlepA mutation decreased ROS levels stimulated by antimicrobial stress. Epistasis experiments showed that EF4 functions in the same genetic pathway as the MazF toxin, a stress response factor implicated in ROS-mediated cell death. The detrimental action of EF4 required transfer-messenger RNA (tmRNA, which tags truncated proteins for degradation and is known to be inhibited by EF4) and the ClpP protease. Inhibition of a protective, tmRNA/ClpP-mediated degradative activity would allow truncated proteins to indirectly perturb the respiratory chain and thereby provide a potential link between EF4 and ROS. The connection among EF4, MazF, tmRNA, and ROS expands a pathway leading from harsh stress to bacterial self-destruction. The destructive aspect of EF4 plus the protective properties described previously make EF4 a bifunctional factor in a stress response that promotes survival or death, depending on the severity of stress. IMPORTANCE Translation elongation factor 4 (EF4) is one of the most conserved proteins in nature, but it is dispensable. Lack of strong phenotypes for its genetic knockout has made EF4 an enigma. Recent biochemical work has demonstrated that mild stress may stall ribosomes and that EF4 can reposition stalled ribosomes to resume proper translation. Thus, EF4 protects cells from moderate stress. Here we report that EF4 is paradoxically harmful during severe stress, such as that caused by antimicrobial treatment. EF4 acts in a pathway that leads to excessive accumulation of reactive oxygen species (ROS), thereby participating in a bacterial self-destruction that occurs when cells cannot effectively repair stress-mediated damage. Thus, EF4 has two opposing functions—at low-to-moderate levels of stress, the protein is protective by allowing stress-paused translation to resume; at high-levels of stress, EF4 helps bacteria self-destruct. These data support the existence of a bacterial live-or-die response to stress.

scholarly journals Programmed Cell-Death by Ferroptosis: Antioxidants as Mitigators

2019 ◽  
Vol 20 (19) ◽  
pp. 4968 ◽  
Author(s):  
Kajarabille ◽  
Latunde-Dada
Keyword(s):  
Reactive Oxygen Species ◽  
Lipid Peroxidation ◽  
Cell Death ◽  
Membrane Lipids ◽  
Glutamate Transporter ◽  
Reactive Oxygen ◽  
Antioxidant Response ◽  
Heme Oxygenase 1 ◽  
Oxygen Species ◽  
Radical Trapping

Iron, the fourth most abundant element in the Earth’s crust, is vital in living organisms because of its diverse ligand-binding and electron-transfer properties. This ability of iron in the redox cycle as a ferrous ion enables it to react with H2O2, in the Fenton reaction, to produce a hydroxyl radical (•OH)—one of the reactive oxygen species (ROS) that cause deleterious oxidative damage to DNA, proteins, and membrane lipids. Ferroptosis is a non-apoptotic regulated cell death that is dependent on iron and reactive oxygen species (ROS) and is characterized by lipid peroxidation. It is triggered when the endogenous antioxidant status of the cell is compromised, leading to lipid ROS accumulation that is toxic and damaging to the membrane structure. Consequently, oxidative stress and the antioxidant levels of the cells are important modulators of lipid peroxidation that induce this novel form of cell death. Remedies capable of averting iron-dependent lipid peroxidation, therefore, are lipophilic antioxidants, including vitamin E, ferrostatin-1 (Fer-1), liproxstatin-1 (Lip-1) and possibly potent bioactive polyphenols. Moreover, most of the enzymes and proteins that cascade or interact in the pathway of ferroptosis such as a subunit of the cystine/glutamate transporter xc- (SLC7A11), glutathione peroxidase 4 (GPX4), and the glutamate–cysteine ligase (GCLC) iron metabolism genes transferrin receptor 1 (TfR1) ferroportin, (Fpn) heme oxygenase 1 (HO-1) and ferritin are regulated by the antioxidant response element of the transcription factor, Nrf2. These, as well as other radical trapping antioxidants (RTAs), are discussed in the current review.

scholarly journals Antibody-induced nonapoptotic cell death in human lymphoma and leukemia cells is mediated through a novel reactive oxygen species-dependent pathway

Blood ◽  
2012 ◽  
Vol 119 (15) ◽  
pp. 3523-3533 ◽  
Author(s):  
Jamie Honeychurch ◽  
Waleed Alduaij ◽  
Mahsa Azizyan ◽  
Eleanor J. Cheadle ◽  
Helene Pelicano ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Cell Death ◽  
Nadph Oxidase ◽  
B Cell ◽  
Reactive Oxygen ◽  
Leukemia Cells ◽  
Oxygen Species ◽  
Type Ii ◽  
B Cell Malignancies ◽  
Anti Cd20

Abstract Monoclonal antibodies (mAbs) have revolutionized the treatment of B-cell malignancies. Although Fc-dependent mechanisms of mAb-mediated tumor clearance have been extensively studied, the ability of mAbs to directly evoke programmed cell death (PCD) in the target cell and the underlying mechanisms involved remain under-investigated. We recently demonstrated that certain mAbs (type II anti-CD20 and anti-HLA DR mAbs) potently evoked PCD through an actin-dependent, lysosome-mediated process. Here, we reveal that the induction of PCD by these mAbs, including the type II anti-CD20 mAb GA101 (obinutuzumab), directly correlates with their ability to produce reactive oxygen species (ROS) in human B-lymphoma cell lines and primary B-cell chronic lymphocytic leukemia cells. ROS scavengers abrogated mAb-induced PCD indicating that ROS are required for the execution of cell death. ROS were generated downstream of mAb-induced actin cytoskeletal reorganization and lysosome membrane permeabilization. ROS production was independent of mitochondria and unaffected by BCL-2 overexpression. Instead, ROS generation was mediated by nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. These findings provide further insights into a previously unrecognized role for NADPH oxidase-derived ROS in mediating nonapoptotic PCD evoked by mAbs in B-cell malignancies. This newly characterized cell death pathway may potentially be exploited to eliminate malignant cells, which are refractory to conventional chemotherapy and immunotherapy.

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