scholarly journals Copper-Containing Nanoparticles and Organic Complexes: Metal Reduction Triggers Rapid Cell Death via Oxidative Burst

2021 ◽  
Vol 22 (20) ◽  
pp. 11065
Author(s):  
Sergey A. Tsymbal ◽  
Anna A. Moiseeva ◽  
Nikol A. Agadzhanian ◽  
Svetlana S. Efimova ◽  
Alina A. Markova ◽  
...  
Keyword(s):  
Cell Death ◽  
Metal Ion ◽  
Membrane Damage ◽  
Organic Ligand ◽  
Direct Interaction ◽  
Metal Reduction ◽  
Ros Generation ◽  
Cuo Nps ◽  
Organic Complexes ◽  
Cu Ions

Copper-containing agents are promising antitumor pharmaceuticals due to the ability of the metal ion to react with biomolecules. In the current study, we demonstrate that inorganic Cu2+ in the form of oxide nanoparticles (NPs) or salts, as well as Cu ions in the context of organic complexes (oxidation states +1, +1.5 and +2), acquire significant cytotoxic potency (2–3 orders of magnitude determined by IC50 values) in combinations with N-acetylcysteine (NAC), cysteine, or ascorbate. In contrast, other divalent cations (Zn, Fe, Mo, and Co) evoked no cytotoxicity with these combinations. CuO NPs (0.1–1 µg/mL) together with 1 mM NAC triggered the formation of reactive oxygen species (ROS) within 2–6 h concomitantly with perturbation of the plasma membrane and caspase-independent cell death. Furthermore, NAC potently sensitized HCT116 colon carcinoma cells to Cu–organic complexes in which the metal ion coordinated with 5-(2-pyridylmethylene)-2-methylthio-imidazol-4-one or was present in the coordination sphere of the porphyrin macrocycle. The sensitization effect was detectable in a panel of mammalian tumor cell lines including the sublines with the determinants of chemotherapeutic drug resistance. The components of the combination were non-toxic if added separately. Electrochemical studies revealed that Cu cations underwent a stepwise reduction in the presence of NAC or ascorbate. This mechanism explains differential efficacy of individual Cu–organic compounds in cell sensitization depending on the availability of Cu ions for reduction. In the presence of oxygen, Cu+1 complexes can generate a superoxide anion in a Fenton-like reaction Cu+1L + O2 → O2−.+ Cu+2L, where L is the organic ligand. Studies on artificial lipid membranes showed that NAC interacted with negatively charged phospholipids, an effect that can facilitate the penetration of CuO NPs across the membranes. Thus, electrochemical modification of Cu ions and subsequent ROS generation, as well as direct interaction with membranes, represent the mechanisms of irreversible membrane damage and cell death in response to metal reduction in inorganic and organic Cu-containing compounds.

scholarly journals CBIO-07. CELL DEATH INDUCED BY AN OSCILLATING MAGNETIC FIELD IN PATIENT DERIVED GLIOBLASTOMA CELLS IS MEDIATED BY REACTIVE OXYGEN SPECIES

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii17-ii17
Author(s):  
Shashank Hambarde ◽  
Martyn Sharpe ◽  
David Baskin ◽  
Santosh Helekar
Keyword(s):  
Reactive Oxygen Species ◽  
Cell Death ◽  
Cell Viability ◽  
Cortical Neurons ◽  
Reactive Oxygen ◽  
Great Promise ◽  
Antioxidant Vitamin ◽  
Ros Generation ◽  
Oxygen Species ◽  
Novel Therapy

Abstract Noninvasive cancer therapy with minimal side effects would be ideal for improving patient outcome in the clinic. We have developed a novel therapy using strong rotating magnets mounted on a helmet. They generate oscillating magnetic fields (OMF) that penetrate through the skull and cover the entire brain. We have demonstrated that OMF can effectively kill patient derived glioblastoma (GBM) cells in cell culture without having cytotoxic effects on cortical neurons and normal human astrocytes (NHA). Exposure of GBM cells to OMF reduced the cell viability by 33% in comparison to sham-treated cells (p< 0.001), while not affecting NHA cell viability. Time lapse video-microscopy for 16 h after OMF exposure showed a marked elevation of mitochondrial reactive oxygen species (ROS), and rapid apoptosis of GBM cells due to activation of caspase 3. Addition of a potent antioxidant vitamin E analog Trolox effectively blocked OMF-induced GBM cell death. Furthermore, OMF significantly potentiated the cytotoxic effect of the pro-oxidant Benzylamine. The results of our studies demonstrate that OMF-induced cell death is mediated by ROS generation. These results demonstrate a potent oncolytic effect on GBM cells that is novel and unrelated to any previously described therapy, including a very different mechanism of action and different technology compared to Optune therapy. The effect is very powerful, and unlike Optune, can be seen within hours after initiation of treatment. We believe that this technology holds great promise for new, effective and nontoxic treatment of glioblastoma.

scholarly journals Ca2+ overload- and ROS-associated mitochondrial dysfunction contributes to δ-tocotrienol-mediated paraptosis in melanoma cells

APOPTOSIS ◽  
2021 ◽  
Author(s):  
Michela Raimondi ◽  
Fabrizio Fontana ◽  
Monica Marzagalli ◽  
Matteo Audano ◽  
Giangiacomo Beretta ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Death ◽  
Mitochondrial Dysfunction ◽  
Atp Synthesis ◽  
Melanoma Cells ◽  
Human Melanoma ◽  
Ros Generation ◽  
Therapy Outcomes ◽  
Human Melanoma Cells ◽  
Oxphos Complex

Abstract Melanoma is an aggressive tumor with still poor therapy outcomes. δ-tocotrienol (δ-TT) is a vitamin E derivative displaying potent anti-cancer properties. Previously, we demonstrated that δ-TT triggers apoptosis in human melanoma cells. Here, we investigated whether it might also activate paraptosis, a non-canonical programmed cell death. In accordance with the main paraptotic features, δ-TT was shown to promote cytoplasmic vacuolization, associated with endoplasmic reticulum/mitochondrial dilation and protein synthesis, as well as MAPK activation in A375 and BLM cell lines. Moreover, treated cells exhibited a significant reduced expression of OXPHOS complex I and a marked decrease in oxygen consumption and mitochondrial membrane potential, culminating in decreased ATP synthesis and AMPK phosphorylation. This mitochondrial dysfunction resulted in ROS overproduction, found to be responsible for paraptosis induction. Additionally, δ-TT caused Ca2+ homeostasis disruption, with endoplasmic reticulum-derived ions accumulating in mitochondria and activating the paraptotic signaling. Interestingly, by using both IP3R and VDAC inhibitors, a close cause-effect relationship between mitochondrial Ca2+ overload and ROS generation was evidenced. Collectively, these results provide novel insights into δ-TT anti-melanoma activity, highlighting its ability to induce mitochondrial dysfunction-mediated paraptosis. Graphic Abstract δ-tocotrienol induces paraptotic cell death in human melanoma cells, causing endoplasmic reticulum dilation and mitochondrial swelling. These alterations induce an impairment of mitochondrial function, ROS production and calcium overload.

scholarly journals Role of hepcidin in oxidative stress and cell death of cultured mouse renal collecting duct cells: protection against iron and sensitization to cadmium

2021 ◽  
Author(s):  
Stephanie Probst ◽  
Johannes Fels ◽  
Bettina Scharner ◽  
Natascha A. Wolff ◽  
Eleni Roussa ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Death ◽  
Cell Fate ◽  
Catalase Activity ◽  
Metal Ion ◽  
Iron Homeostasis ◽  
Collecting Duct ◽  
Duct Cell ◽  
Plasmid Transfection

AbstractThe liver hormone hepcidin regulates systemic iron homeostasis. Hepcidin is also expressed by the kidney, but exclusively in distal nephron segments. Several studies suggest hepcidin protects against kidney damage involving Fe2+ overload. The nephrotoxic non-essential metal ion Cd2+ can displace Fe2+ from cellular biomolecules, causing oxidative stress and cell death. The role of hepcidin in Fe2+ and Cd2+ toxicity was assessed in mouse renal cortical [mCCD(cl.1)] and inner medullary [mIMCD3] collecting duct cell lines. Cells were exposed to equipotent Cd2+ (0.5–5 μmol/l) and/or Fe2+ (50–100 μmol/l) for 4–24 h. Hepcidin (Hamp1) was transiently silenced by RNAi or overexpressed by plasmid transfection. Hepcidin or catalase expression were evaluated by RT-PCR, qPCR, immunoblotting or immunofluorescence microscopy, and cell fate by MTT, apoptosis and necrosis assays. Reactive oxygen species (ROS) were detected using CellROX™ Green and catalase activity by fluorometry. Hepcidin upregulation protected against Fe2+-induced mIMCD3 cell death by increasing catalase activity and reducing ROS, but exacerbated Cd2+-induced catalase dysfunction, increasing ROS and cell death. Opposite effects were observed with Hamp1 siRNA. Similar to Hamp1 silencing, increased intracellular Fe2+ prevented Cd2+ damage, ROS formation and catalase disruption whereas chelation of intracellular Fe2+ with desferrioxamine augmented Cd2+ damage, corresponding to hepcidin upregulation. Comparable effects were observed in mCCD(cl.1) cells, indicating equivalent functions of renal hepcidin in different collecting duct segments. In conclusion, hepcidin likely binds Fe2+, but not Cd2+. Because Fe2+ and Cd2+ compete for functional binding sites in proteins, hepcidin affects their free metal ion pools and differentially impacts downstream processes and cell fate.

Reperfusion injury on cardiac myocytes after simulated ischemia

1996 ◽  
Vol 270 (4) ◽  
pp. H1334-H1341 ◽  
Author(s):  
T. L. Vanden Hoek ◽  
Z. Shao ◽  
C. Li ◽  
R. Zak ◽  
P. T. Schumacker ◽  
...  
Keyword(s):  
Cell Death ◽  
Reperfusion Injury ◽  
Cell Injury ◽  
Membrane Damage ◽  
Cardiac Injury ◽  
Cellular Membrane ◽  
Iodide Uptake ◽  
Membrane Injury ◽  
Simulated Ischemia ◽  
Lactate Dehydrogenase Release

The extent of cardiac injury incurred during reperfusion as opposed to that occurring during ischemia is unclear. This study tested the hypothesis that simulated ischemia followed by simulated reperfusion causes significant "reperfusion injury" in isolated chick cardiomyocytes. Cells were exposed to hypoxia, hypercarbic acidosis, hyperkalemia, and substrate deprivation for 1 h followed by 3 h of reperfusion. Irreversible cell membrane injury, measured by propidium iodide uptake, increased from 4% of cells at the end of ischemia to 73% after reperfusion; death occurred in only 17% of cells kept ischemic for 4 h. Lactate dehydrogenase release was consistent with these changes. Lengthening ischemia from 30 to 90 min increased cell injury as expected, but of the total cell death, > 90% occurred during reperfusion. "Chemical hypoxia" composed of cyanide (2.5 mM) plus 2-deoxyglucose augmented injury before reperfusion compared with simulated ischemia. Inhibition of oxygen radical generation by use of metal chelator 1,10-phenanthroline reduced cell death from 73% to 40% after reperfusion (P = 0.001). We conclude that simulated reperfusion significantly augments the cellular membrane damage elicited by simulated ischemia in isolated cardiomyocytes devoid of other factors and suggest that reactive oxygen species, perhaps from the mitochondria, participate in this injury.

scholarly journals Identification and Characterization of NTB451 as a Potential Inhibitor of Necroptosis

Molecules ◽  
2018 ◽  
Vol 23 (11) ◽  
pp. 2884 ◽  
Author(s):  
Eun-Jung In ◽  
Yuno Lee ◽  
Sushruta Koppula ◽  
Tae-Yeon Kim ◽  
Jun-Hyuk Han ◽  
...  
Keyword(s):  
Cell Death ◽  
Md Simulation ◽  
Ischemia Reperfusion Injury ◽  
Apoptotic Cell ◽  
Ischemia Reperfusion ◽  
Direct Interaction ◽  
Inhibitory Effect ◽  
Therapeutic Implications ◽  
Pathological Conditions ◽  
Tnf Α

Necroptosis, or caspase-independent programmed cell death, is known to be involved in various pathological conditions, such as ischemia/reperfusion injury, myocardial infarction, atherosclerosis, and inflammatory bowel diseases. Although several inhibitors of necroptosis have been identified, none of them are currently in clinical use. In the present study, we identified a new compound, 4-({[5-(4-aminophenyl)-4-ethyl-4H-1,2,4-triazol-3-yl]sulfanyl}methyl)-N-(1,3-thiazol-2-yl) benzamide (NTB451), with significant inhibitory activity on the necroptosis induced by various triggers, such as tumor necrosis factor-α (TNF-α) and toll-like receptor (TLR) agonists. Mechanistic studies revealed that NTB451 inhibited phosphorylation and oligomerization of mixed lineage kinase domain like (MLKL), and this activity was linked to its inhibitory effect on the formation of the receptor interacting serine/threonine-protein kinase 1 (RIPK1)-RIPK3 complex. Small interfering RNA (siRNA)-mediated RIPK1 knockdown, drug affinity responsive target stability assay, and molecular dynamics (MD) simulation study illustrated that RIPK1 is a specific target of NTB451. Moreover, MD simulation showed a direct interaction of NTB451 and RIPK1. Further experiments to ensure that the inhibitory effect of NTB451 was restricted to necroptosis and NTB451 had no effect on nuclear factor-κB (NF-κB) activation or apoptotic cell death upon triggering with TNF-α were also performed. Considering the data obtained, our study confirmed the potential of NTB451 as a new necroptosis inhibitor, suggesting its therapeutic implications for pathological conditions induced by necroptotic cell death.

scholarly journals Potential mechanisms of quantitative resistance to Leptosphaeria maculans (blackleg) on cotyledons of canola (Brassica napus)

2020 ◽  
Author(s):  
Michelle Hubbard ◽  
Chun Zhai ◽  
Gary Peng
Keyword(s):  
Signal Transduction ◽  
Cell Death ◽  
Fluorescent Protein ◽  
Quantitative Resistance ◽  
Leptosphaeria Maculans ◽  
Small Gtpases ◽  
Ros Generation ◽  
Ros Production ◽  
Potential Marker ◽  
Starting Point

Abstract Background: Blackleg disease, caused by Leptosphaeria maculans (Lm), can lead to significant losses of canola/rapeseed crops. Growing resistant canola cultivars can be an effective and environmentally friendly way to manage blackleg. Major resistance genes may stop infection, but can also be rapidly overcome by shifts in pathogen population towards virulence. Thus, using race-nonspecific or quantitative resistance (QR) is of interest because it is potentially more durable. However, the mechanisms and genes underlying QR are mostly unknown. In this study, we explored QR in “74‑44 BL”, a Canadian canola cultivar carrying a moderate level of race nonspecific resistance, based on cotyledon inoculation (Supple. Fig.1) . The susceptible cultivar “Westar” was used as a control. Lesions developed more slowly on 74-44BL than on Westar. We used RNA-Seq to identify genes and gene functions putatively involved in the QR. Results: Relative to inoculated Westar, some of the B. napus genes that were differentially expressed strongly in inoculated 74-44 BL included those putatively involved in programmed cell death (PCD), reactive oxygen species (ROS) generation, signal transduction and/or intracellular endomembrane transport. Examples included genes annotated as a Bax inhibitor 1, a development/cell death (DCD) domain containing proteinases and peptidases, all of which could play a role in PCD and a zinc-finger Sec23/Sec24 and five small GTPases likely involved in endoplasmic reticulum (ER) to Golgi vesicle traffic and/or signal transduction. Further experiments, however, did not confirm changes in genomic DNA degradation, a potential marker for PCD, between the two cultivars. In addition, infection progression in cotyledons was not altered by applying protease inhibitors directly to cotyledons. Additional testing was done using green fluorescent protein (GFP)-tagged Lm for cotyledon colonization as well as ROS production, in relation to the lesion development. The results showed that ROS production occurred beyond the area colonized by Lm hyphae in 74-44 BL.Conclusions: ROS may also be involved in signal transduction and/or intracellular endomembrane transport. These results provide a starting point for a better understanding of the mechanisms behind QR against Lm in canola and developing new host-resistance strategies for management of blackleg.

scholarly journals Imatinib protects against human beta-cell death via inhibition of mitochondrial respiration and activation of AMPK

2021 ◽  
Author(s):  
Andris Elksnis ◽  
Tomas A Schiffer ◽  
Fredrik Palm ◽  
Yun Wang ◽  
Jing Cen ◽  
...  
Keyword(s):  
Cell Death ◽  
Tyrosine Kinase ◽  
Beta Cell ◽  
Mitochondrial Respiration ◽  
Kinase Inhibitor ◽  
Direct Interaction ◽  
Ampk Activation ◽  
Beta Cell Death ◽  
Compound C

The protein tyrosine kinase inhibitor imatinib is used in the treatment of various malignancies, but may also promote beneficial effects in the treatment of diabetes. The aim of the present investigation was to characterize the mechanisms by which imatinib protects insulin producing cells. Treatment of NOD mice with imatinib resulted in increased beta-cell AMPK phosphorylation. Imatinib activated AMPK also in vitro, resulting in decreased ribosomal protein S6 phosphorylation and protection against IAPP-aggregation, TXNIP upregulation and beta-cell death. AICAR mimicked and compound C counteracted the effect of imatinib on beta-cell survival. Imatinib-induced AMPK activation was preceded by reduced glucose/pyruvate-dependent respiration, increased glycolysis rates, and a lowered ATP/AMP ratio. Imatinib augmented the fractional oxidation of fatty acids/malate, possibly via a direct interaction with the beta-oxidation enzyme ECHS1. In non-beta cells, imatinib reduced respiratory chain complex I and II-mediated respiration and ACC phosphorylation, suggesting that mitochondrial effects of imatinib are not beta-cell specific. In conclusion, tyrosine kinase inhibitors modestly inhibit mitochondrial respiration, leading to AMPK activation and TXNIP downregulation, which in turn protects against beta-cell death.

Epicatechin and its in vivo metabolite, 3′-O-methyl epicatechin, protect human fibroblasts from oxidative-stress-induced cell death involving caspase-3 activation

2001 ◽  
Vol 354 (3) ◽  
pp. 493-500 ◽  
Author(s):  
Jeremy P. E. SPENCER ◽  
Hagen SCHROETER ◽  
Gunter KUHNLE ◽  
S. Kaila S. SRAI ◽  
Rex M. TYRRELL ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Cell Death ◽  
Caspase 3 ◽  
Cell Damage ◽  
Protective Action ◽  
Human Fibroblasts ◽  
Membrane Damage ◽  
Antioxidant Properties

There is considerable current interest in the cytoprotective effects of natural antioxidants against oxidative stress. In particular, epicatechin, a major member of the flavanol family of polyphenols with powerful antioxidant properties in vitro, has been investigated to determine its ability to attenuate oxidative-stress-induced cell damage and to understand the mechanism of its protective action. We have induced oxidative stress in cultured human fibroblasts using hydrogen peroxide and examined the cellular responses in the form of mitochondrial function, cell-membrane damage, annexin-V binding and caspase-3 activation. Since one of the major metabolites of epicatechin in vivo is 3′-O-methyl epicatechin, we have compared its protective effects with that of epicatechin. The results provide the first evidence that 3′-O-methyl epicatechin inhibits cell death induced by hydrogen peroxide and that the mechanism involves suppression of caspase-3 activity as a marker for apoptosis. Furthermore, the protection elicited by 3′-O-methyl epicatechin is not significantly different from that of epicatechin, suggesting that hydrogen-donating antioxidant activity is not the primary mechanism of protection.

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