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The ROS/JNK/ATF2 pathway mediates selenite-induced leukemia NB4 cell cycle arrest and apoptosis in vitro and in vivo.  

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It has previously been shown that selenite can act as an antitumor agent and inhibit cancer cell growth, although the mechanism responsible for this effect is not well understood. In this study, we have shown that selenite can induce cell cycle arrest and apoptosis in NB4 cells. Selenite treatment of these cells also inhibited the JNK/ATF2 axis. Further experiments demonstrated that selenite-induced production of reactive oxygen species (ROS) worked as an upstream of the JNK/ATF2 axis, cell cycle arrest and apoptosis. Inactivation of ATF2 resulted in decreased affinity of this transcription factor for the promoters of cyclin A, cyclin D3 and CDK4, which led to the arrest of the NB4 cells in the G0/G1 phase. Finally, in vivo experiments confirmed the antitumor activity of selenite and the mechanisms that were described in vitro. Taken together, our results indicate that selenite-induced ROS arrest NB4 cells at G0/G1 phase through inhibiting the JNK/ATF2 axis in vitro and in vivo. PMID:24357804

An, J J; Shi, K J; Wei, W; Hua, F Y; Ci, Y L; Jiang, Q; Li, F; Wu, P; Hui, K Y; Yang, Y; Xu, C M

2013-01-01

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Selenite induces apoptosis in colorectal cancer cells via AKT-mediated inhibition of ?-catenin survival axis.  

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Mounting evidence reveals that selenium possesses chemotherapeutic potential against cancer cells. However, the molecular mechanisms underlying the anti-cancer effect of selenium remain elusive. In this study, with the aim to explore the detailed mechanisms how selenite induces apoptosis in colorectal cancer cells, we investigated the role of AKT/?-catenin signaling, a critical regulator of cell proliferation, survival and tumorigenesis, in selenite-induced apoptosis of colorectal cancer cells and xenograft tumors. We showed that selenite exerted a remarkable inhibitory effect on activation of AKT, leading to suppression of ?-catenin activity and expression of its targets: cyclin D1 and survivin. Further experiments by transient expression of AKT and ?-catenin revealed that inhibition of AKT/?-catenin was closely correlated with selenite-triggered apoptosis. Importantly, MnTMPyP pretreatment implied reactive oxygen species (ROS) was a crucial upstream signal for selenite-triggered inhibition of AKT/?-catenin. Overall, these observations demonstrate that selenite could induce apoptosis through ROS-dependent inhibition of AKT/?-catenin signaling in colorectal cancer cells in vitro and in vivo, and our findings yield novel insights into elucidating the mechanisms involved in the anti-cancer effect of selenium. PMID:22074856

Luo, Hui; Yang, Yang; Huang, Fang; Li, Feng; Jiang, Qian; Shi, Kejian; Xu, Caimin

2012-02-01

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Prevention of selenite induced oxidative stress and cataractogenesis by luteolin isolated from Vitex negundo.  

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Free radical mediated oxidative stress plays a crucial role in the pathogenesis of cataract and the present study was to determine the efficacy of luteolin in preventing selenite induced oxidative stress and cataractogenesis in vitro. Luteolin is a bioactive flavonoid, isolated and characterized from the leaves of Vitex negundo. Lenses were extracted from Sprague-Dawley strain rats and were organ cultured in DMEM medium. They were divided into three groups with eight lenses in each group as follows: lenses cultured in normal medium (G I), supplemented with 0.1mM sodium selenite (G II) and sodium selenite and 2 ?g/ml luteolin (G III). Treatment was from the second to fifth day, while selenite administration was done on the third day. After the experimental period, lenses were taken out and various parameters were studied. The antioxidant potential of luteolin was assessed by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. In the selenite induced group, morphological examination of the lenses showed dense cortical opacification and vacuolization. Biochemical examinations revealed a significant decrease in activities of antioxidant enzymes and enzymes of the glutathione system. Additionally decreased glutathione level and increased reactive oxygen species (ROS) and thiobarbituric acid reactive substances (TBARS) were observed. Luteolin treatment abated selenite induced oxidative stress and cataractogenesis by maintaining antioxidant status, reducing ROS generation and lipid peroxidation in the lens. These finding demonstrated the anticataractogenic effect of luteolin by virtue of its antioxidant property, which has been reported in this paper for the first time. PMID:22342831

Rooban, B N; Sasikala, V; Gayathri Devi, V; Sahasranamam, V; Abraham, Annie

2012-03-01

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Prevention of Selenite-induced Cataractogenesis by Origanum vulgare Extract  

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Full Text Available The present study sought to assess antioxidant effect of Origanum vulgare extract in preventing selenite-induced cataractogenesis. This study was performed on Young white rats received sodium selenite (30 nmol g-1 birth weight subcutaneously on day 13 post partum during two months in 2009. Cataract formation and intensity was detected and measured by slit-lamp. Origanum vulgare (Ov extract (2 g kg-1 was given (1-2 times intraperitoneal at different times with respect to the selenite administration lens opacification was analyzed in selenite, selenite-Ov, Ov and control groups on day 7 after selenite administration. Ov extract have revealed a significant protective effect against selenite induced cataract when injected 1 and 2 day (2 times before selenite injection. There is a protective effect of Ov against selenite induced cataract formation. It is supposed that the anticataract effect of Ov extract could be based on direct or indirect antioxidant mechanisms.

M. Lashgari

2010-01-01

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Aging Aggravates Nitrate-Mediated ROS/RNS Changes  

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Nitrates are the most frequently prescribed and utilized drugs worldwide. The elderly are a major population receiving nitrate therapy. Both nitrates and aging can increase in vivo reactive oxygen species (ROS) and reactive nitrogen species (RNS). To date, the effects of aging upon nitrate-induced ROS/RNS alteration are unknown. The present study tested the effects of aging upon nitrate-induced ROS/RNS alteration in vivo. 32 adults and 43 elderly unstable angina (UA) patients were subjected to 48 hours of isosorbide dinitrate intravenous injection (50??g/minutes) in this clinical study. Blood samples were obtained at baseline and conclusion. Outcome measures of oxidative stress included plasma malondialdehyde (MDA), myeloperoxidase (MPO), and reduced glutathione (GSH). Plasma concentrations of NOx and nitrotyrosine served as markers of RNS. Because of the significant differences in basic clinical characters between adults and the elderly, we designed an additional experiment determining ROS/RNS stress in rat cardiac tissue. Additionally, rat thoracic aortic NOS activity served as a marker indicating endothelial function. Our study demonstrated that nitrate therapy significantly increased in vivo ROS/RNS stress in the elderly compared to adult patients, confirmed by animal data. Decreased NOS activity was observed in old rats. Taken together, the present study's data suggests a synergism between nitrate treatment and the aging process.

Fan, Qian; Chen, Lifen; Cheng, Shujuan; Li, Fang; Lau, Wayne Bond; Wang, Le Feng; Liu, Jing Hua

2014-01-01

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Laser-induced osteoblast proliferation is mediated by ROS production.  

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Low-level laser therapy (LLLT) is widely used in regenerative medicine and in dental therapy by virtue of its beneficial effects in a plethora of pathological conditions. In this study, the effect of a 980 nm diode laser on pre-osteoblasts proliferation has been evaluated, along with reactive oxygen species (ROS) production. We hypothesized that ROS were a key factor in LLLT-induced pre-osteoblasts proliferation, as it is known that ROS can induce the activation of many biological pathways, leading to cell proliferation, differentiation or apoptosis. Murine pre-osteoblasts MC3T3 cells were irradiated with different energy outputs (1-50 J) in the absence or presence of the antioxidant N-Acetyl-L-cysteine (NAC). Laser treatment, in the absence of NAC, was able to induce a fluence-dependent statistically significant increase in ROS generation, while the presence of NAC strongly inhibited it. Cell proliferation, measured after laser stimulation, was significantly increased both at low and higher energy, with a peak at 10 J in the absence of the antioxidant. On the contrary, in the presence of NAC, laser irradiation was not able to induce any cell proliferation, suggesting a crucial role of ROS in this laser-induced cell effect. These results suggest that LLLT may be a useful tool for bone regeneration therapy and an effective range of fluences to be used is indicated. PMID:24595962

Migliario, Mario; Pittarella, Pamela; Fanuli, Matteo; Rizzi, Manuela; Renň, Filippo

2014-07-01

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Aging aggravates nitrate-mediated ROS/RNS changes.  

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Nitrates are the most frequently prescribed and utilized drugs worldwide. The elderly are a major population receiving nitrate therapy. Both nitrates and aging can increase in vivo reactive oxygen species (ROS) and reactive nitrogen species (RNS). To date, the effects of aging upon nitrate-induced ROS/RNS alteration are unknown. The present study tested the effects of aging upon nitrate-induced ROS/RNS alteration in vivo. 32 adults and 43 elderly unstable angina (UA) patients were subjected to 48 hours of isosorbide dinitrate intravenous injection (50? ?g/minutes) in this clinical study. Blood samples were obtained at baseline and conclusion. Outcome measures of oxidative stress included plasma malondialdehyde (MDA), myeloperoxidase (MPO), and reduced glutathione (GSH). Plasma concentrations of NOx and nitrotyrosine served as markers of RNS. Because of the significant differences in basic clinical characters between adults and the elderly, we designed an additional experiment determining ROS/RNS stress in rat cardiac tissue. Additionally, rat thoracic aortic NOS activity served as a marker indicating endothelial function. Our study demonstrated that nitrate therapy significantly increased in vivo ROS/RNS stress in the elderly compared to adult patients, confirmed by animal data. Decreased NOS activity was observed in old rats. Taken together, the present study's data suggests a synergism between nitrate treatment and the aging process. PMID:24790702

Fan, Qian; Chen, Lifen; Cheng, Shujuan; Li, Fang; Lau, Wayne Bond; Wang, Le Feng; Liu, Jing Hua

2014-01-01

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Sodium selenite-induced activation of DAPK promotes autophagy in human leukemia HL60 cells  

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Full Text Available Autophagy has been suggested as a possible mechanism fornon-apoptotic death despite evidence from many species thatautophagy represents a survival strategy of cells under stress.From our previous findings that supranutritional doses ofsodium selenite induced apoptosis in human leukemia cells,now we show autophagic cell death occurred after seleniteexposure in HL60, suggested an alternative mechanism for thepotential therapeutic properties of selenite. Additionally,Death-associated Protein Kinase (DAPK performed a significantlyincreased expression during this process, concomitantlywith gradually decreased phosphorylation at Ser308. We furtherreveal that the up-regulation of DAPK which depends onselenite-activated ERK had no effect on autophagy. However,activation of DAPK via PP2A-mediated dephosphorylation atSer308 serves as a new strategy for autophagy induction. Inconclusion, these results indicate that PP2A-mediated activatedDAPK sensitizes HL60 cells to selenite, ultimately triggersautophagic cell death pathway to commit cell demise. [BMBreports 2012; 45(3: 194-199

Qian Jiang

2012-03-01

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Preventive effect of onion juice on selenite-induced experimental cataract  

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Purpose: To evaluate the effects of onion juice on sodium-selenite induced cataract formation. Materials and Methods: Thirty-two 10-day-old Wistar-albino rat pups were divided into four equal groups. Group 1 received only subcutaneous saline injection. In Group 2, sodium-selenite (30 nmol?/?g body weight) was injected subcutaneously. In Group 3, subcutaneous sodium-selenite was injected and one drop 50% diluted fresh juice of crude onion was instilled every...

Javadzadeh Alireza; Ghorbanihaghjo Amir; Bonyadi Somayeh; Rashidi Mohammad; Mesgari Mehran; Rashtchizadeh Nadereh; Argani Hassan

2009-01-01

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Artemisinin induces ROS-mediated caspase3 activation in ASTC-a-1 cells  

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Artemisinin (ART), an antimalarial phytochemical from the sweet wormwood plant or a naturally occurring component of Artemisia annua, has been shown a potential anticancer activity by apoptotic pathways. In our report, cell counting kit (CCK-8) assay showed that treatment of human lung adenocarcinoma (ASTC-a-1) cells with ART effectively increase cell death by inducing apoptosis in a time- and dose-dependent fashion. Hoechst 33258 staining was used to detect apoptosis as well. Reactive oxygen species (ROS) generation was observed in cells exposed to ART at concentrations of 400 ?M for 48 h. N-acetyl-L-cysteine (NAC), an oxygen radical scavenger, suppressed the rate of ROS generation and inhibited the ART-induced apoptosis. Moreover, AFC assay (Fluorometric assay for Caspase3 activity) showed that ROS was involved in ART-induced caspase3 acitvation. Taken together, our data indicate that ART induces ROS-mediated caspase3 activation in a time-and dose-dependent way in ASCT-a-1 cells.

Xiao, Feng-Lian; Chen, Tong-Sheng; Qu, Jun-Le; Liu, Cheng-Yi

2010-02-01

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Costunolide induces apoptosis by ROS-mediated mitochondrial permeability transition and cytochrome C release.  

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Costunolide is an active compound isolated from the root of Saussurea lappa Clarks, a Chinese medicinal herb, and is considered a therapeutic candidate for various types of cancers. Nevertheless, the pharmacological pathways of costunolide are still unknown. In this study, we investigate the effects of costunolide on the induction of apoptosis in HL-60 human leukemia cells and its putative pathways of action. Using apoptosis analysis, measurement of reactive oxygen species (ROS), and assessment of mitochondrial membrane potentials, we show that costunolide is a potent inducer of apoptosis, and facilitates its activity via ROS generation, thereby inducing mitochondrial permeability transition (MPT) and cytochrome c release to the cytosol. ROS production, mitochondrial alteration, and subsequent apoptotic cell death in costunolide-treated cells were blocked by the antioxidant N-acetylcystein (NAC). Cyclosporin A, a permeability transition inhibitor, also inhibited mitochondrial permeability transition and apoptosis. Our data indicate that costunolide induces the ROS-mediated mitochondrial permeability transition and resultant cytochrome c release. This is the first report on the mechanism of the anticancer effect of costunolide. PMID:11256490

Lee, M G; Lee, K T; Chi, S G; Park, J H

2001-03-01

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Vitex negundo modulates selenite-induced opacification and cataractogensis in rat pups.  

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Recently, much interest has been generated in the search for phytochemical therapeutics, as they are largely free from adverse side effects and economical. The goal of this study was to determine the efficacy of Vitex negundo in modulating the selenite-induced oxidative stress in vivo model. Sprague-Dawley rat pups of 8 days old were used for the study and divided into control (G I), selenite induced (G II), and selenite + V. negundo treated (G III). Cataract was induced by the single subcutaneous injection of sodium selenite (4 mg/kg body weight) on the tenth day and V. negundo (2.5 mg/Kg body weight) administered intraperitoneally from eighth to 15th day. Morphological examination of the rat lenses revealed no opacification in G I and mild opacification in G III whereas dense opacification in G II (stages 4-6). Levels of selenium in G II and G III showed no significant changes. The activities of superoxide dismutase, catalase, and Ca(2+)ATPase were significantly increased in G III compared to G II (p negundo on modulating biochemical parameters against selenite-induced cataract, which have been reported in this paper for the first time. PMID:20174976

Rooban, B N; Sasikala, V; Sahasranamam, V; Abraham, Annie

2010-12-01

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Mitochondrial Ca˛+ and ROS take center stage to orchestrate TNF-?-mediated inflammatory responses.  

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Proinflammatory stimuli induce inflammation that may progress to sepsis or chronic inflammatory disease. The cytokine TNF-? is an important endotoxin-induced inflammatory glycoprotein produced predominantly by macrophages and lymphocytes. TNF-? plays a major role in initiating signaling pathways and pathophysiological responses after engaging TNF receptors. In this issue of JCI, Rowlands et al. demonstrate that in lung microvessels, soluble TNF-? (sTNF-?) promotes the shedding of the TNF-? receptor 1 ectodomain via increased mitochondrial Ca˛+ that leads to release of mitochondrial ROS. Shedding mediated by TNF-?-converting enzyme (TACE) results in an unattached TNF receptor, which participates in the scavenging of sTNF-?, thus limiting the propagation of the inflammatory response. These findings suggest that mitochondrial Ca˛+, ROS, and TACE might be therapeutically targeted for treating pulmonary endothelial inflammation. PMID:21519140

Dada, Laura A; Sznajder, Jacob I

2011-05-01

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Mitochondrial Ca2+ and ROS take center stage to orchestrate TNF-?-mediated inflammatory responses  

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Proinflammatory stimuli induce inflammation that may progress to sepsis or chronic inflammatory disease. The cytokine TNF-? is an important endotoxin-induced inflammatory glycoprotein produced predominantly by macrophages and lymphocytes. TNF-? plays a major role in initiating signaling pathways and pathophysiological responses after engaging TNF receptors. In this issue of JCI, Rowlands et al. demonstrate that in lung microvessels, soluble TNF-? (sTNF-?) promotes the shedding of the TNF-? receptor 1 ectodomain via increased mitochondrial Ca2+ that leads to release of mitochondrial ROS. Shedding mediated by TNF-?–converting enzyme (TACE) results in an unattached TNF receptor, which participates in the scavenging of sTNF-?, thus limiting the propagation of the inflammatory response. These findings suggest that mitochondrial Ca2+, ROS, and TACE might be therapeutically targeted for treating pulmonary endothelial inflammation.

Dada, Laura A.; Sznajder, Jacob I.

2011-01-01

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Cadmium-induced teratogenicity: Association with ROS-mediated endoplasmic reticulum stress in placenta  

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The placenta is essential for sustaining the growth of the fetus. An increased endoplasmic reticulum (ER) stress has been associated with the impaired placental and fetal development. Cadmium (Cd) is a potent teratogen that caused fetal malformation and growth restriction. The present study investigated the effects of maternal Cd exposure on placental and fetal development. The pregnant mice were intraperitoneally injected with CdCl{sub 2} (4.5 mg/kg) on gestational day 9. As expected, maternal Cd exposure during early limb development significantly increased the incidences of forelimb ectrodactyly in fetuses. An obvious impairment in the labyrinth, a highly developed tissue of blood vessels, was observed in placenta of mice treated with CdCl{sub 2}. In addition, maternal Cd exposure markedly repressed cell proliferation and increased apoptosis in placenta. An additional experiment showed that maternal Cd exposure significantly upregulated the expression of GRP78, an ER chaperone. Moreover, maternal Cd exposure induced the phosphorylation of placental eIF2?, a downstream molecule of PERK signaling. In addition, maternal Cd exposure significantly increased the level of placental CHOP, another target of PERK signaling, indicating that the unfolded protein response (UPR) signaling was activated in placenta of mice treated with CdCl{sub 2}. Interestingly, alpha-phenyl-N-t-butylnitrone, a free radical spin-trapping agent, significantly alleviated Cd-induced placental ER stress and UPR. Taken together, these results suggest that reactive oxygen species (ROS)-mediated ER stress might be involved in Cd-induced impairment on placental and fetal development. Antioxidants may be used as pharmacological agents to protect against Cd-induced fetal malformation and growth restriction. -- Highlights: ? Cd induces fetal malformation and growth restriction. ? Cd induced placental ER stress and UPR. ? PBN alleviates Cd-induced ER stress and UPR in placenta. ? ROS-mediated ER stress might be involved in Cd-induced placental impairments. ? ROS-mediated ER stress might be involved in Cd-induced fetal malformations.

Wang, Zhen; Wang, Hua; Xu, Zhong Mei; Ji, Yan-Li; Chen, Yuan-Hua; Zhang, Zhi-Hui; Zhang, Cheng; Meng, Xiu-Hong; Zhao, Mei; Xu, De-Xiang, E-mail: xudex@126.com

2012-03-01

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ROS-mediated upregulation of Noxa overcomes chemoresistance in chronic lymphocytic leukemia.  

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In recent years considerable progress has been made in treatment strategies for chronic lymphocytic leukemia (CLL). However, the disease remains incurable because of the development of chemoresistance. Strategies to overcome resistance mechanisms are therefore highly needed. At least two mechanisms contribute to the development of resistance to drugs; acquired mutations resulting in a dysfunctional p53 response and shifts in the balance between apoptosis-regulating proteins. Platinum-based compounds have been successfully applied in relapsed lymphoma and recently also in high-risk CLL. In this study we investigated the efficacy and mechanism of action of cisplatinum (CDDP) in chemorefractory CLL. Independent of p53-functional status, CDDP acted synergistically with fludarabine (F-ara-A). The response involved generation of reactive oxygen species (ROS), which led to specific upregulation of the proapoptotic BH3-only protein Noxa. Induction of Noxa resulted in cell death by apoptosis as inhibition of caspase activation completely abrogated cell death. Furthermore, drug-resistance upon CD40-ligand stimulation, a model for the protective stimuli provided in lymph nodes, could also be overcome by CDDP/F-ara-A. ROS accumulation resulted in Noxa upregulation mainly at the transcriptional level and this was, at least in part, mediated by the mitogen-activated protein kinase p38. Finally, Noxa RNA-interference markedly decreased sensitivity to CDDP/F-ara-A, supporting a key role for Noxa as mediator between ROS signaling and apoptosis induction. Our data indicate that interference in the cellular redox balance can be exploited to overcome chemoresistance in CLL. PMID:20935673

Tonino, S H; van Laar, J; van Oers, M H; Wang, J Y; Eldering, E; Kater, A P

2011-02-10

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The Intrinsic Apoptosis Pathway Mediates the Pro-Longevity Response to Mitochondrial ROS in C. elegans.  

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The increased longevity of the C. elegans electron transport chain mutants isp-1 and nuo-6 is mediated by mitochondrial ROS (mtROS) signaling. Here we show that the mtROS signal is relayed by the conserved, mitochondria-associated, intrinsic apoptosis signaling pathway (CED-9/Bcl2, CED-4/Apaf1, and CED-3/Casp9) triggered by CED-13, an alternative BH3-only protein. Activation of the pathway by an elevation of mtROS does not affect apoptosis but protects from the consequences of mitochondrial dysfunction by triggering a unique pattern of gene expression that modulates stress sensitivity and promotes survival. In vertebrates, mtROS induce apoptosis through the intrinsic pathway to protect from severely damaged cells. Our observations in nematodes demonstrate that sensing of mtROS by the apoptotic pathway can, independently of apoptosis, elicit protective mechanisms that keep the organism alive under stressful conditions. This results in extended longevity when mtROS generation is inappropriately elevated. These findings clarify the relationships between mitochondria, ROS, apoptosis, and aging. PMID:24813612

Yee, Callista; Yang, Wen; Hekimi, Siegfried

2014-05-01

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ROS and Sympathetically mediated Mitochondria activation in Brown Adipose Tissue contributes to Methamphetamine-induced hyperthermia  

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Full Text Available Methamphetamine abuse has been shown to induce alterations in mitochondrial function in the brain as well as to induce hyperthermia, which contributes to neurotoxicity and Meth-associated mortality. Brown adipose tissue (BAT, a thermogenic site known to be important in neonates, has recently regained importance since being identified in significant amounts and in correlation with metabolic balance in human adults. Given the high mitochondrial content of BAT and its role in thermogenesis, we aimed to investigate whether BAT plays any role in the development of Meth-induced hyperthermia. By ablating or denervating BAT, we identified a partial contribution of this organ to Meth-induced hyperthermia. BAT ablation decreased temperature by 0.5oC and reduced the length of hyperthermia by 1 hr, compared to sham-operated controls. BAT denervation also affected the development of hyperthermia in correlation with decreased the expression of electron transport chain molecules, and increase on PCG1a levels, but without affecting Meth-induced UCP1 upregulation. Furthermore, in isolated BAT cells in culture, Meth, but not Norepinephrine (NE, induced H2O2 upregulation. In addition, we found that in vivo Reactive Oxygen Species (ROS play a role in Meth hyperthermia. Thus, sympathetically- mediated mitochondrial activation in the BAT and Meth-induced ROS are key components to the development of hyperthermia in Meth abuse.

Maria CeciliaGMarcondes

2013-04-01

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Preventive effect of onion juice on selenite-induced experimental cataract  

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Full Text Available Purpose: To evaluate the effects of onion juice on sodium-selenite induced cataract formation. Materials and Methods: Thirty-two 10-day-old Wistar-albino rat pups were divided into four equal groups. Group 1 received only subcutaneous saline injection. In Group 2, sodium-selenite (30 nmol?/?g body weight was injected subcutaneously. In Group 3, subcutaneous sodium-selenite was injected and one drop 50% diluted fresh juice of crude onion was instilled every 8 h into the right eye for 14 days; the left eye received no treatment. Group 4 rats were similar to those of Group 3, the only difference being that of undiluted fresh juice of crude onion. The development of cataract was assessed. Rat lenses were analyzed for total antioxidant (TA level, and for activities of glutathione peroxidase (GPX and superoxide dismutase (SOD. Results: Both eyes of all rats in Group 1 did not exhibit cataract formation . In Group 2, all rats developed Grade 3 cataract in the lenses of both eyes. The difference in exhibited cataract in the lens of the right eyes in all rats between Group 2 and any eyes of groups 3 or 4 were significant ( P = 0.001. The mean TA level and mean activities of SOD and GPX in Group 2 rat lenses were significantly lower than the values in lenses of all rats in Group 1 ( P = 0.001, 0.003, 0.001, and in the lenses of the right eyes of rats in Groups 3 and 4 ( P = 0.001, 0.020, 0.001. Conclusion: Instillation of onion juice into the rat eyes can effectively prevent selenite-induced cataract formation. This effect was associated with increased TA level, SOD and GPX activities in the lens.

Javadzadeh Alireza

2009-01-01

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Divalent metal transporter 1 regulates iron-mediated ROS and pancreatic Ă? cell fate in response to cytokines  

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Reactive oxygen species (ROS) contribute to target-cell damage in inflammatory and iron-overload diseases. Little is known about iron transport regulation during inflammatory attack. Through a combination of in vitro and in vivo studies, we show that the proinflammatory cytokine IL-1� induces divalent metal transporter 1 (DMT1) expression correlating with increased � cell iron content and ROS production. Iron chelation and siRNA and genetic knockdown of DMT1 expression reduce cytokine-induced ROS formation and cell death. Glucose-stimulated insulin secretion in the absence of cytokines in Dmt1 knockout islets is defective, highlighting a physiological role of iron and ROS in the regulation of insulin secretion. Dmt1 knockout mice are protected against multiple low-dose streptozotocin and high-fat diet-induced glucose intolerance, models of type 1 and type 2 diabetes, respectively. Thus, � cells become prone to ROS-mediated inflammatory damage via aberrant cellular iron metabolism, a finding with potential general cellular implications.

Hansen, Jakob Bondo; Tonnesen, Morten Fog

2012-01-01

 
 
 
 
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Divalent Metal Transporter 1 Regulates Iron-Mediated ROS and Pancreatic β Cell Fate in Response to Cytokines  

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Reactive oxygen species (ROS) contribute to target-cell damage in inflammatory and iron-overload diseases. Little is known about iron transport regulation during inflammatory attack. Through a combination of in vitro and in vivo studies, we show that the proinflammatory cytokine IL-1β induces divalent metal transporter 1 (DMT1) expression correlating with increased β cell iron content and ROS production. Iron chelation and siRNA and genetic knockdown of DMT1 expression reduce cytokine-induced ROS formation and cell death. Glucose-stimulated insulin secretion in the absence of cytokines in Dmt1 knockout islets is defective, highlighting a physiological role of iron and ROS in the regulation of insulin secretion. Dmt1 knockout mice are protected against multiple low-dose streptozotocin and high-fat diet-induced glucose intolerance, models of type 1 and type 2 diabetes, respectively. Thus, β cells become prone to ROS-mediated inflammatory damage via aberrant cellular iron metabolism, a finding with potential general cellular implications.

Hansen, Jakob Bondo; Tonnesen, Morten Fog

2012-01-01

22

ROS accumulation and IGF-IR inhibition contribute to fenofibrate/PPAR? -mediated inhibition of Glioma cell motility in vitro  

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Full Text Available Abstract Background Glioblastomas are characterized by rapid cell growth, aggressive CNS infiltration, and are resistant to all known anticancer regimens. Recent studies indicate that fibrates and statins possess anticancer potential. Fenofibrate is a potent agonist of peroxisome proliferator activated receptor alpha (PPAR? that can switch energy metabolism from glycolysis to fatty acid ?-oxidation, and has low systemic toxicity. Fenofibrate also attenuates IGF-I-mediated cellular responses, which could be relevant in the process of glioblastoma cell dispersal. Methods The effects of fenofibrate on Glioma cell motility, IGF-I receptor (IGF-IR signaling, PPAR? activity, reactive oxygen species (ROS metabolism, mitochondrial potential, and ATP production were analyzed in human glioma cell lines. Results Fenofibrate treatment attenuated IGF-I signaling responses and repressed cell motility of LN-229 and T98G Glioma cell lines. In the absence of fenofibrate, specific inhibition of the IGF-IR had only modest effects on Glioma cell motility. Further experiments revealed that PPAR?-dependent accumulation of ROS is a strong contributing factor in Glioma cell lines responses to fenofibrate. The ROS scavenger, N-acetyl-cysteine (NAC, restored cell motility, improved mitochondrial potential, and increased ATP levels in fenofibrate treated Glioma cell lines. Conclusions Our results indicate that although fenofibrate-mediated inhibition of the IGF-IR may not be sufficient in counteracting Glioma cell dispersal, PPAR?-dependent metabolic switch and the resulting ROS accumulation strongly contribute to the inhibition of these devastating brain tumor cells.

Del Valle Luis

2010-06-01

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Evaluation of anticataract potential of Triphala in selenite-induced cataract: In vitro and in vivo studies  

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Triphala (TP) is composed of Emblica officinalis, Terminalia chebula, and Terminalia belerica. The present study was undertaken to evaluate its anticataract potential in vitro and in vivo in a selenite-induced experimental model of cataract. In vitro enucleated rat lenses were maintained in organ culture containing Dulbecco’s Modified Eagles Medium alone or with the addition of 100?M selenite. These served as the normal and control groups, respectively. In the test group, the medium was su...

Gupta, Suresh Kumar; Kalaiselvan, V.; Srivastava, Sushma; Agrawal, Shyam S.; Saxena, Rohit

2010-01-01

24

ROS-mediated activation of AKT induces apoptosis via pVHL in prostate cancer cells.  

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Reactive oxygen species (ROS) play a central role in oxidative stress, which leads to the onset of diseases, such as cancer. Furthermore, ROS contributes to the delicate balance between tumor cell survival and death. However, the mechanisms by which tumor cells decide to elicit survival or death signals during oxidative stress are not completely understood. We have previously reported that ROS enhanced tumorigenic functions in prostate cancer cells, such as transendothelial migration and invasion, which depended on CXCR4 and AKT signaling. Here, we report a novel mechanism by which ROS facilitated cell death through activation of AKT. We initially observed that ROS enhanced the expression of phosphorylated AKT (p-AKT) in 22Rv1 human prostate cancer cells. The tumor suppressor PTEN, a negative regulator of AKT signaling, was rendered catalytically inactive through oxidation by ROS, although the expression levels remained consistent. Despite these events, cells still underwent apoptosis. Further investigation into apoptosis revealed that expression of the tumor suppressor pVHL increased, and contains a target site for p-AKT phosphorylation. pVHL and p-AKT associated in vitro, and knockdown of pVHL rescued HIF1? expression and the cells from apoptosis. Collectively, our study suggests that in the context of oxidative stress, p-AKT facilitated apoptosis by inducing pVHL function. PMID:23315288

Chetram, Mahandranauth A; Bethea, Danaya A; Odero-Marah, Valerie A; Don-Salu-Hewage, Ayesha S; Jones, Kia J; Hinton, Cimona V

2013-04-01

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P66Shc-rac1 pathway-mediated ROS production and cell migration is downregulated by ascorbic acid.  

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The oxidative role(s) of p66Shc protein has been increasingly expanded over the last decade. However, its relation with the most potent antioxidant molecule, i.e. ascorbic acid has never been studied. We have previously shown that p66Shc mediates rac1 activation, reactive oxygen species (ROS) production and cell death. Here we studied the effect of ascorbic acid on the pathway involving p66Shc and rac1. Our results indicate a decrease in the expression of p66Shc in a dose- and time-dependent manner. We studied the effect of ascorbic acid on rac1 expression and its activity. Ascorbic acid has no effect on total rac1 expression; however, rac1 activation was inhibited in a dose-dependent manner. Results suggest that the decrease in rac1 activity is mediated through ascorbic acid-modulated p66Shc expression. The decrease in rac1 activity was evident in cells transfected with the p66shc mutant (proline motif mutant, at residues P47 to P50). Our studies indicate that p66Shc-mediated ROS upregulation is significantly decreased in the presence of ascorbic acid. Cell migration experiments point towards the inhibition of p66Shc-rac1-mediated migration in the presence of ascorbic acid. Finally, results are suggestive that ascorbic acid-mediated decrease in Shc expression occurs through an increased Shc ubiquitination. Overall, the study brings out the novel role of ascorbic acid in antioxidant signal transduction. PMID:23461363

Kirmani, Deeba; Bhat, Hina F; Bashir, Muneesa; Zargar, Mohammad A; Khanday, Firdous A

2013-04-01

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Estrogen-induced DNA synthesis in vascular endothelial cells is mediated by ROS signaling  

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Full Text Available Abstract Background Since estrogen is known to increase vascular endothelial cell growth, elevated estrogen exposure from hormone replacement therapy or oral contraceptives has the potential to contribute in the development of abnormal proliferative vascular lesions and subsequent thickening of the vasculature. How estrogen may support or promote vascular lesions is not clear. We have examined in this study whether estrogen exposure to vascular endothelial cells increase the formation of reactive oxygen species (ROS, and estrogen-induced ROS is involved in the growth of endothelial cells. Methods The effect of estrogen on the production of intracellular oxidants and the role of estrogen-induced ROS on cell growth was studied in human umbilical vein endothelial cells. ROS were measured by monitoring the oxidation of 2'7'-dichlorofluorescin by spectrofluorometry. Endothelial cell growth was measured by a colorimetric immunoassay based on BrdU incorporation into DNA. Results Physiological concentrations of estrogen (367 fmol and 3.67 pmol triggered a rapid 2-fold increase in intracellular oxidants in endothelial cells. E2-induced ROS formation was inhibited to basal levels by cotreatment with the mitochondrial inhibitor rotenone (2 ?M and xanthine oxidase inhibitor allopurinol (50 ?M. Inhibitors of NAD(PH oxidase, apocynin and DPI, did not block E2-induced ROS formation. Furthermore, the NOS inhibitor, L-NAME, did not prevent the increase in E2-induced ROS. These findings indicate both mitochondria and xanthine oxidase are the source of ROS in estrogen treated vascular endothelial cells. E2 treated cells showed a 2-fold induction of BrdU incorporation at 18 h which was not observed in cells exposed to vehicle alone. Cotreatment with ebselen (20 ?M and NAC (1 mM inhibited E2-induced BrdU incorporation without affecting the basal levels of DNA synthesis. The observed inhibitory effect of NAC and ebselen on E2-induced DNA synthesis was also shown to be dose dependent. Conclusion We have shown that estrogen exposure stimulates the rapid production of intracellular ROS and they are involved in growth signaling of endothelial cells. It appears that the early estrogen signaling does not require estrogen receptor genomic signaling because we can inhibit estrogen-induced DNA synthesis by antioxidants. Findings of this study may further expand research defining the underlying mechanism of how estrogen may promote vascular lesions. It also provides important information for the design of new antioxidant-based drugs or new antioxidant gene therapy to protect the cardiovascular health of individuals sensitive to estrogen.

Felty Quentin

2006-04-01

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ROS introduction  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The open source "Robot Operating System" ROS offers highly developed robotics software components which can be used in flexible industrial applications. This introduction to ROS gives an overview about the capabillities and tools provided by ROS.

Weißhardt, Florian

2013-01-01

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Cytotoxic effects of 15d-PGJ2 against osteosarcoma through ROS-mediated AKT and cell cycle inhibition.  

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Polo-like kinase 1 (PLK1), a critical cell cycle regulator, has been identified as a potential target in osteosarcoma (OS). 15-deoxy-?12, 14-prostaglandin J2 (15d-PGJ2), a prostaglandin derivative, has shown its anti-tumor activity by inducing apoptosis through reactive oxygen species (ROS)-mediated inactivation of v-akt, a murine thymoma viral oncogene homolog, (AKT) in cancer cells. In the study analyzing its effects on arthritis, 15d-PGJ2 mediated shear-induced chondrocyte apoptosis via protein kinase A (PKA)-dependent regulation of PLK1. In this study, the cytotoxic effect and mechanism underlying 15d-PGJ2 effects against OS were explored using OS cell lines. 15d-PGJ2 induced significant G2/M arrest, and exerted time- and dose-dependent cytotoxic effects against all OS cell lines. Western blot analysis showed that both AKT and PKA-PLK1 were down-regulated in OS cell lines after treatment with 15d-PGJ2. In addition, transfection of constitutively active AKT or PLK1 partially rescued cells from 15d-PGJ2-induced apoptosis, suggesting crucial roles for both pathways in the anti-cancer effects of 15d-PGJ2. Moreover, ROS generation was found treatment with 15d-PGJ2, and its cytotoxic effect could be reversed with N-acetyl-l-cysteine. Furthermore, inhibition of JNK partially rescued 15d-PGJ2 cytotoxicity. Thus, ROS-mediated JNK activation may contribute to apoptosis through down-regulation of the p-Akt and PKA-PLK1 pathways. 15d-PGJ2 is a potential therapeutic agent for OS, exerting cytotoxicity mediated through both AKT and PKA-PLK1 inhibition, and these results form the basis for further analysis of its role in animal studies and clinical applications. PMID:24566468

Yen, Chueh-Chuan; Hsiao, Chung-Der; Chen, Wei-Ming; Wen, Yao-Shan; Lin, Yung-Chan; Chang, Ting-Wei; Yao, Fang-Yi; Hung, Shih-Chieh; Wang, Jir-You; Chiu, Jen-Hwey; Wang, Hsei-Wei; Lin, Chi-Hung; Chen, Tain-Hsiung; Chen, Paul Chih-Hsueh; Liu, Chien-Lin; Tzeng, Cheng-Hwai; Fletcher, Jonathan A

2014-02-15

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Cytotoxic effects of 15d-PGJ2 against osteosarcoma through ROS-mediated AKT and cell cycle inhibition  

Science.gov (United States)

Polo-like kinase 1 (PLK1), a critical cell cycle regulator, has been identified as a potential target in osteosarcoma (OS). 15-deoxy-?12, 14-prostaglandin J2 (15d-PGJ2), a prostaglandin derivative, has shown its anti-tumor activity by inducing apoptosis through reactive oxygen species (ROS)-mediated inactivation of v-akt, a murine thymoma viral oncogene homolog, (AKT) in cancer cells. In the study analyzing its effects on arthritis, 15d-PGJ2 mediated shear-induced chondrocyte apoptosis via protein kinase A (PKA)-dependent regulation of PLK1. In this study, the cytotoxic effect and mechanism underlying 15d-PGJ2 effects against OS were explored using OS cell lines. 15d-PGJ2 induced significant G2/M arrest, and exerted time- and dose-dependent cytotoxic effects against all OS cell lines. Western blot analysis showed that both AKT and PKA-PLK1 were down-regulated in OS cell lines after treatment with 15d-PGJ2. In addition, transfection of constitutively active AKT or PLK1 partially rescued cells from 15d-PGJ2-induced apoptosis, suggesting crucial roles for both pathways in the anti-cancer effects of 15d-PGJ2. Moreover, ROS generation was found treatment with 15d-PGJ2, and its cytotoxic effect could be reversed with N-acetyl-l-cysteine. Furthermore, inhibition of JNK partially rescued 15d-PGJ2 cytotoxicity. Thus, ROS-mediated JNK activation may contribute to apoptosis through down-regulation of the p-Akt and PKA-PLK1 pathways. 15d-PGJ2 is a potential therapeutic agent for OS, exerting cytotoxicity mediated through both AKT and PKA-PLK1 inhibition, and these results form the basis for further analysis of its role in animal studies and clinical applications.

Chen, Wei-Ming; Wen, Yao-Shan; Lin, Yung-Chan; Chang, Ting-Wei; Yao, Fang-Yi; Hung, Shih-Chieh; Wang, Jir-You; Chiu, Jen-Hwey; Wang, Hsei-Wei; Lin, Chi-Hung; Chen, Tain-Hsiung; Chen, Paul Chih-Hsueh; Liu, Chien-Lin; Tzeng, Cheng-Hwai; Fletcher, Jonathan A.

2014-01-01

30

ROS-mediated vascular homeostatic control of root-to-shoot soil Na delivery in Arabidopsis.  

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Sodium (Na) is ubiquitous in soils, and is transported to plant shoots via transpiration through xylem elements in the vascular tissue. However, excess Na is damaging. Accordingly, control of xylem-sap Na concentration is important for maintenance of shoot Na homeostasis, especially under Na stress conditions. Here we report that shoot Na homeostasis of Arabidopsis thaliana plants grown in saline soils is conferred by reactive oxygen species (ROS) regulation of xylem-sap Na concentrations. We show that lack of A. thaliana respiratory burst oxidase protein F (AtrbohF; an NADPH oxidase catalysing ROS production) causes hypersensitivity of shoots to soil salinity. Lack of AtrbohF-dependent salinity-induced vascular ROS accumulation leads to increased Na concentrations in root vasculature cells and in xylem sap, thus causing delivery of damaging amounts of Na to the shoot. We also show that the excess shoot Na delivery caused by lack of AtrbohF is dependent upon transpiration. We conclude that AtrbohF increases ROS levels in wild-type root vasculature in response to raised soil salinity, thereby limiting Na concentrations in xylem sap, and in turn protecting shoot cells from transpiration-dependent delivery of excess Na. PMID:23064146

Jiang, Caifu; Belfield, Eric J; Mithani, Aziz; Visscher, Anne; Ragoussis, Jiannis; Mott, Richard; Smith, J Andrew C; Harberd, Nicholas P

2012-11-14

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Nickel (II)-induced cytotoxicity and apoptosis in human proximal tubule cells through a ROS- and mitochondria-mediated pathway  

International Nuclear Information System (INIS)

Nickel compounds are known to be toxic and carcinogenic in kidney and lung. In this present study, we investigated the roles of reactive oxygen species (ROS) and mitochondria in nickel (II) acetate-induced cytotoxicity and apoptosis in the HK-2 human renal cell line. The results showed that the cytotoxic effects of nickel (II) involved significant cell death and DNA damage. Nickel (II) increased the generation of ROS and induced a noticeable reduction of mitochondrial membrane potential (MMP). Analysis of the sub-G1 phase showed a significant increase in apoptosis in HK-2 cells after nickel (II) treatment. Pretreatment with N-acetylcysteine (NAC) not only inhibited nickel (II)-induced cell death and DNA damage, but also significantly prevented nickel (II)-induced loss of MMP and apoptosis. Cell apoptosis triggered by nickel (II) was characterized by the reduced protein expression of Bcl-2 and Bcl-xL and the induced the protein expression of Bad, Bcl-Xs, Bax, cytochrome c and caspases 9, 3 and 6. The regulation of the expression of Bcl-2-family proteins, the release of cytochrome c and the activation of caspases 9, 3 and 6 were inhibited in the presence of NAC. These results suggest that nickel (II) induces cytotoxicity and apoptosis in HK-2 cells via ROS generation and that the mitochondria-mediated apoptotic signaling pathway may be involved in the positive regulation of nickel (II)-induced renal cytotoxicity.

2012-03-01

32

Chimaphilin induces apoptosis in human breast cancer MCF-7 cells through a ROS-mediated mitochondrial pathway.  

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Chimaphilin, 2,7-dimethyl-1,4-naphthoquinone, is extracted from pyrola [Passiflora incarnata Fisch.]. In this study, the anticancer activity and underlying mechanisms of chimaphilin toward human breast cancer MCF-7 cells are firstly investigated. Chimaphilin could inhibit the viability of MCF-7 cells in a concentration-dependent manner, and the IC50 value was 43.30?M for 24h. Chimaphilin markedly induced apoptosis through the investigation of characteristic apoptotic morphological changes, nuclear DNA fragmentation, annexin V-FITC/propidium iodide (PI) double staining. Flow cytometry assay revealed that chimaphilin triggered a significant generation of ROS and disruption of mitochondrial membrane potential. Additionally, western blotting assay showed that chimaphilin suppressed Bcl-2 level and enhanced Bad level, then activated caspase-9 and caspase-3, and further activated the poly ADP-ribose polymerase (PARP), finally induced cell apoptosis involving the mitochondrial pathway. Furthermore, free radical scavengers N-acetyl-L-cysteine (NAC) pretreatment test testified that chimaphilin could increase the generation of ROS, then induce cell apoptosis. In general, the present results demonstrated that chimaphilin induced apoptosis in human breast cancer MCF-7 cells via a ROS-mediated mitochondrial pathway. PMID:24793375

Ma, Wei-Dong; Zou, Yong-Peng; Wang, Peng; Yao, Xiao-Hui; Sun, Yao; Duan, Ming-Hui; Fu, Yu-Jie; Yu, Bo

2014-08-01

33

HIF-1-mediated metabolic reprogramming reduces ROS levels and facilitates the metastatic colonization of cancers in lungs  

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Hypoxia-inducible factor 1 (HIF-1) has been associated with distant tumor metastasis; however, its function in multiple metastatic processes has not yet been fully elucidated. In the present study, we demonstrated that cancer cells transiently upregulated HIF-1 activity during their metastatic colonization after extravasation in the lungs in hypoxia-independent and reactive oxygen species (ROS)-dependent manners. Transient activation induced the expression of lactate dehydrogenase A and phosphorylation of the E1? subunit of pyruvate dehydrogenase, which indicated the reprogramming of glucose metabolic pathways from mitochondrial oxidative phosphorylation to anaerobic glycolysis and lactic acid fermentation. The administration of the HIF-1 inhibitor, YC-1, inhibited this reprogramming, increased intratumoral ROS levels, and eventually suppressed the formation of metastatic lung tumors. These results indicate that HIF-1-mediated metabolic reprogramming is responsible for the survival of metastatic cancers during their colonization in lungs by reducing cytotoxic ROS levels; therefore, its blockade by HIF-1-inhibitors is a rational strategy to prevent tumor metastasis.

Zhao, Tao; Zhu, Yuxi; Morinibu, Akiyo; Kobayashi, Minoru; Shinomiya, Kazumi; Itasaka, Satoshi; Yoshimura, Michio; Guo, Guozheng; Hiraoka, Masahiro; Harada, Hiroshi

2014-01-01

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Cerium Oxide Nanoparticles Induced Toxicity in Human Lung Cells: Role of ROS Mediated DNA Damage and Apoptosis.  

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Cerium oxide nanoparticles (CeO2 NPs) have promising industrial and biomedical applications. In spite of their applications, the toxicity of these NPs in biological/physiological environment is a major concern. Present study aimed to understand the molecular mechanism underlying the toxicity of CeO2 NPs on lung adenocarcinoma (A549) cells. After internalization, CeO2 NPs caused significant cytotoxicity and morphological changes in A549 cells. Further, the cell death was found to be apoptotic as shown by loss in mitochondrial membrane potential and increase in annexin-V positive cells and confirmed by immunoblot analysis of BAX, BCl-2, Cyt C, AIF, caspase-3, and caspase-9. A significant increase in oxidative DNA damage was found which was confirmed by phosphorylation of p53 gene and presence of cleaved poly ADP ribose polymerase (PARP). This damage could be attributed to increased production of reactive oxygen species (ROS) with concomitant decrease in antioxidant "glutathione (GSH)" level. DNA damage and cell death were attenuated by the application of ROS and apoptosis inhibitors N-acetyl-L- cysteine (NAC) and Z-DEVD-fmk, respectively. Our study concludes that ROS mediated DNA damage and cell cycle arrest play a major role in CeO2 NPs induced apoptotic cell death in A549 cells. Apart from beneficial applications, these NPs also impart potential harmful effects which should be properly evaluated prior to their use. PMID:24987704

Mittal, Sandeep; Pandey, Alok K

2014-01-01

35

Cerium Oxide Nanoparticles Induced Toxicity in Human Lung Cells: Role of ROS Mediated DNA Damage and Apoptosis  

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Cerium oxide nanoparticles (CeO2 NPs) have promising industrial and biomedical applications. In spite of their applications, the toxicity of these NPs in biological/physiological environment is a major concern. Present study aimed to understand the molecular mechanism underlying the toxicity of CeO2 NPs on lung adenocarcinoma (A549) cells. After internalization, CeO2 NPs caused significant cytotoxicity and morphological changes in A549 cells. Further, the cell death was found to be apoptotic as shown by loss in mitochondrial membrane potential and increase in annexin-V positive cells and confirmed by immunoblot analysis of BAX, BCl-2, Cyt C, AIF, caspase-3, and caspase-9. A significant increase in oxidative DNA damage was found which was confirmed by phosphorylation of p53 gene and presence of cleaved poly ADP ribose polymerase (PARP). This damage could be attributed to increased production of reactive oxygen species (ROS) with concomitant decrease in antioxidant “glutathione (GSH)” level. DNA damage and cell death were attenuated by the application of ROS and apoptosis inhibitors N-acetyl-L- cysteine (NAC) and Z-DEVD-fmk, respectively. Our study concludes that ROS mediated DNA damage and cell cycle arrest play a major role in CeO2 NPs induced apoptotic cell death in A549 cells. Apart from beneficial applications, these NPs also impart potential harmful effects which should be properly evaluated prior to their use.

Pandey, Alok K.

2014-01-01

36

ROS-mediated killing efficiency with visible light of bacteria carrying different red fluorochrome proteins.  

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Red fluorescent proteins can generate reactive oxygen species (ROS) if their fluorochrome is stimulated e.g. by visible light illumination. ROS compounds have very reactive, highly toxic properties leading to cell damage which results in cell killing. In this context, the toxicity of the various red fluorochromes KillerRed, DsRed2, mCherry, and mRFP expressed in Escherichia coli bacteria was tested after illumination with white light. The toxic effect was determined by measurement of the colony forming ability 24h after transfection and illumination. KillerRed was found to be the most harmful, followed by mRFP and DsRed2 while bacteria expressing mCherry and controls without fluorescent proteins survived after application of identical illumination doses. Their application and a possible bactericide role is discussed. PMID:22296652

Waldeck, Waldemar; Heidenreich, Elena; Mueller, Gabriele; Wiessler, Manfred; Tóth, Katalin; Braun, Klaus

2012-04-01

37

Cracking the Cytotoxicity Code: Apoptotic Induction of 10-Acetylirciformonin B is Mediated through ROS Generation and Mitochondrial Dysfunction  

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Full Text Available A marine furanoterpenoid derivative, 10-acetylirciformonin B (10AB, was found to inhibit the proliferation of leukemia, hepatoma, and colon cancer cell lines, with selective and significant potency against leukemia cells. It induced DNA damage and apoptosis in leukemia HL 60 cells. To fully understand the mechanism behind the 10AB apoptotic induction against HL 60 cells, we extended our previous findings and further explored the precise molecular targets of 10AB. We found that the use of 10AB increased apoptosis by 8.9%–87.6% and caused disruption of mitochondrial membrane potential (MMP by 15.2%–95.2% in a dose-dependent manner, as demonstrated by annexin-V/PI and JC-1 staining assays, respectively. Moreover, our findings indicated that the pretreatment of HL 60 cells with N-acetyl-l-cysteine (NAC, a reactive oxygen species (ROS scavenger, diminished MMP disruption and apoptosis induced by 10AB, suggesting that ROS overproduction plays a crucial rule in the cytotoxic activity of 10AB. The results of a cell-free system assay indicated that 10AB could act as a topoisomerase catalytic inhibitor through the inhibition of topoisomerase II?. On the protein level, the expression of the anti-apoptotic proteins Bcl-xL and Bcl-2, caspase inhibitors XIAP and survivin, as well as hexokinase II were inhibited by the use of 10AB. On the other hand, the expression of the pro-apoptotic protein Bax was increased after 10AB treatment. Taken together, our results suggest that 10AB-induced apoptosis is mediated through the overproduction of ROS and the disruption of mitochondrial metabolism.

Huei-Chuan Shih

2014-05-01

38

Nuclear translocation of B-cell-specific transcription factor, BACH2, modulates ROS mediated cytotoxic responses in mantle cell lymphoma.  

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BACH2, a B-cell specific transcription factor, plays a critical role in oxidative stress-mediated apoptosis. Bortezomib (Velcade(TM)) is widely used to treat relapsed mantle cell lymphoma (MCL) patients despite varying clinical outcomes. As one of the potential mechanisms of action, bortezomib was reported to elicit endoplasmic reticulum (ER) stress which triggers reactive oxygen species (ROS). In the present study, we investigated the redox-sensitive intracellular mechanism that might play a critical role in bortezomib response in MCL cells. We demonstrated that in MCL cells that are sensitive to bortezomib treatments, BACH2 was translocated to the nucleus in response to bortezomib and induced apoptotic responses through the modulation of anti-oxidative and anti-apoptotic genes. On the other hand, in bortezomib resistant cells, BACH2 expression was confined in the cytoplasm and no suppression of antiapoptotic or antioxidative genes, Nrf2, Gss, CAT, HO-1 and MCL1, was detected. Importantly, levels of BACH2 were significantly higher in bortezomib sensitive MCL patient cells, indicating that BACH2 levels could be an indicator for clinical bortezomib responses. BACH2 translocation to the cytoplasm after phosphorylation was inhibited by PI3K inhibitors and combinatory regimens of bortezomib and PI3K inhibitors sensitized MCL cells to bortezomib. These data suggest that cellular distribution of BACH2 in response to ROS determines the threshold for the induction of apoptosis. Therapies that inhibit BACH2 phosphorylation could be the key for increasing bortezomib cytotoxic response in patients. PMID:23936317

Chen, Zheng; Pittman, Eric F; Romaguera, Jorge; Fayad, Luis; Wang, Michael; Neelapu, Sattva S; McLaughlin, Peter; Kwak, Larry; McCarty, Nami

2013-01-01

39

TGF-?1-ROS-ATM-CREB signaling axis in macrophage mediated migration of human breast cancer MCF7 cells.  

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Macrophages in the tumor microenvironment play an important role in tumor cell survival. They influence the tumor cell to proliferate, invade into surrounding normal tissues and metastasize to local and distant sites. In this study, we evaluated the effect of conditioned medium from monocytes and macrophages on growth and migration of breast cancer cells. Macrophage conditioned medium (M?CM) containing elevated levels of cytokines TNF-?, IL-1? and IL-6 had a differential effect on non-invasive (MCF7) and highly invasive (MDA-MB-231) breast cancer cell lines. M?CM induced the secretion of TGF-?1 in MCF7 cells. This was associated with apoptosis in a fraction of cells and generation of reactive oxygen and nitrogen species (ROS and RNS) and DNA damage in the remaining cells. This, in turn, increased expression of cAMP response element binding protein (CREB) and vimentin resulting in migration of cells. These effects were inhibited by neutralization of TNF-?, IL-1? and IL-6, inhibition of ROS and RNS, DNA damage and siRNA mediated knockdown of ATM. In contrast, MDA-MB-231 cells which had higher basal levels of pCREB were not affected by M?CM. In summary, we have found that pro-inflammatory cytokines secreted by macrophages induce TGF-?1 in tumor cells, which activate pCREB signaling, epithelial-mesenchymal-transition (EMT) responses and enhanced migration. PMID:24705025

Singh, Rajshri; Shankar, Bhavani S; Sainis, Krishna B

2014-07-01

40

Shikonin targets cytosolic thioredoxin reductase to induce ROS-mediated apoptosis in human promyelocytic leukemia HL-60 cells.  

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Shikonin, a major active component of the Chinese herbal plant Lithospermum erythrorhizon, has been applied for centuries in traditional Chinese medicine. Although shikonin demonstrates potent anticancer efficacy in numerous types of human cancer cells, the cellular targets of shikonin have not been fully defined. We report here that shikonin may interact with the cytosolic thioredoxin reductase (TrxR1), an important selenocysteine (Sec)-containing antioxidant enzyme with a C-terminal -Gly-Cys-Sec-Gly active site, to induce reactive oxygen species (ROS)-mediated apoptosis in human promyelocytic leukemia HL-60 cells. Shikonin primarily targets the Sec residue in TrxR1 to inhibit its physiological function, but further shifts the enzyme to an NADPH oxidase to generate superoxide anions, which leads to accumulation of ROS and collapse of the intracellular redox balance. Importantly, overexpression of functional TrxR1 attenuates the cytotoxicity of shikonin, whereas knockdown of TrxR1 sensitizes cells to shikonin treatment. Targeting TrxR1 with shikonin thus discloses a previously unrecognized mechanism underlying the biological activity of shikonin and provides an in-depth insight into the action of shikonin in the treatment of cancer. PMID:24583460

Duan, Dongzhu; Zhang, Baoxin; Yao, Juan; Liu, Yaping; Fang, Jianguo

2014-05-01

 
 
 
 
41

Pharmacologic IKK/NF-?B inhibition causes antigen presenting cells to undergo TNF? dependent ROS-mediated programmed cell death  

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Monocyte-derived antigen presenting cells (APC) are central mediators of the innate and adaptive immune response in inflammatory diseases. As such, APC are appropriate targets for therapeutic intervention to ameliorate certain diseases. APC differentiation, activation and functions are regulated by the NF-?B family of transcription factors. Herein, we examined the effect of NF-?B inhibition, via suppression of the I?B Kinase (IKK) complex, on APC function. Murine bone marrow-derived macrophages and dendritic cells (DC), as well as macrophage and DC lines, underwent rapid programmed cell death (PCD) after treatment with several IKK/NF-?B inhibitors through a TNF?-dependent mechanism. PCD was induced proximally by reactive oxygen species (ROS) formation, which causes a loss of mitochondrial membrane potential and activation of a caspase signaling cascade. NF-?B-inhibition-induced PCD of APC may be a key mechanism through which therapeutic targeting of NF-?B reduces inflammatory pathologies.

Tilstra, Jeremy S.; Gaddy, Daniel F.; Zhao, Jing; Davé, Shaival H.; Niedernhofer, Laura J.; Plevy, Scott E.; Robbins, Paul D.

2014-01-01

42

Induction of apoptosis by isoegomaketone from Perilla frutescens L. in B16 melanoma cells is mediated through ROS generation and mitochondrial-dependent, -independent pathway.  

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We have demonstrated for the first time the mechanism underlying ROS-mediated mitochondria-dependent apoptotic cell death triggered by isoegomaketone (IK) treatment in melanoma cells. We showed that IK induced apoptotic cell death and tumor growth inhibition using tissue culture and in vivo models of B16 melanoma. Furthermore, we observed that IK effectively induced apoptotic cell death, including sub-G1 contents up-regulation, nuclei condensation, DNA fragmentation, and caspase activation in B16 melanoma cells. Pretreatment with caspase inhibitor increased the survival rate of IK-treated B16 cells, implying that caspases play a role in IK-induced apoptosis. Furthermore, IK treatment generated ROS in melanoma cells. We also determined whether or not IK-induced cell death is due to ROS production in B16 cells. N-acetyl cysteine (NAC) inhibitedIK-induced Bcl-2 family-mediated apoptosis. This result indicates that IK-induced apoptosis involves ROS generation as well as up-regulation of Bax and Bcl-2 expression, leading to release of cytochrome c and AIF. Our data suggest that IK inhibits growth and induces apoptosis in melanoma cells via activation of ROS-mediated caspase-dependent and -independent pathways. PMID:24380754

Kwon, Soon-Jae; Lee, Ju-Hye; Moon, Kwang-Deog; Jeong, Il-Yun; Ahn, Dong-U K; Lee, Mi-Kyung; Seo, Kwon-Il

2014-03-01

43

Melatonin elevates apoptosis in human platelets via ROS mediated mitochondrial damage.  

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Melatonin is a pineal hormone that regulates circadian and seasonal rhythms. The chronobiotic role of melatonin corresponds with a repertoire of pharmacological properties. Besides, it has a wide range of therapeutic applications. However, recent studies have demonstrated its direct interaction with platelets: at physiological concentration it promotes platelet aggregation; on the other hand, at pharmacological doses it raises intracellular Ca(2+) leading to platelet activation, thrombus formation and cardiovascular disorders. In order to further probe its effects on platelets, the current study targeted platelet apoptosis and melatonin was found to stimulate apoptosis. The mitochondrial pathway of apoptosis was mainly investigated because of its susceptibility to oxidative stress-inducing factors including therapeutic and dietary elements. Melatonin significantly increased the generation of intracellular ROS and Ca(2+), facilitating mitochondrial membrane depolarization, cytochrome c release, caspase activation, protein phosphorylation and phosphatidylserine externalization. Further, the overall toxicity of melatonin on platelets was confirmed by MTT and lactate dehydrogenase assays. The elevated rate of platelet apoptosis has far reaching consequences including thrombocytopenia. Besides, platelets undergoing apoptosis release microparticles, which fuel thrombus formation and play a significant role in the pathophysiology of a number of diseases. In many parts of the world melatonin is an over-the-counter dietary supplement and alternative medicine. Since, melatonin displays platelet proapoptotic effect at a concentration attainable through therapeutic dosage, the present study sends a warning signal to the chronic use of melatonin as a therapeutic drug and questions its availability without a medical prescription. PMID:23880341

Girish, Kesturu Subbaiah; Paul, Manoj; Thushara, Ram Mohan; Hemshekhar, Mahadevappa; Shanmuga Sundaram, Mahalingam; Rangappa, Kanchugarakoppal Subbegowda; Kemparaju, Kempaiah

2013-08-16

44

Sodium fluoride induces apoptosis in mouse embryonic stem cells through ROS-dependent and caspase- and JNK-mediated pathways  

International Nuclear Information System (INIS)

Sodium fluoride (NaF) is used as a source of fluoride ions in diverse applications. Fluoride salt is an effective prophylactic for dental caries and is an essential element required for bone health. However, fluoride is known to cause cytotoxicity in a concentration-dependent manner. Further, no information is available on the effects of NaF on mouse embryonic stem cells (mESCs). We investigated the mode of cell death induced by NaF and the mechanisms involved. NaF treatment greater than 1 mM reduced viability and DNA synthesis in mESCs and induced cell cycle arrest in the G2/M phase. The addition of NaF induced cell death mainly by apoptosis rather than necrosis. Catalase (CAT) treatment significantly inhibited the NaF-mediated cell death and also suppressed the NaF-mediated increase in phospho-c-Jun N-terminal kinase (p-JNK) levels. Pre-treatment with SP600125 or z-VAD-fmk significantly attenuated the NaF-mediated reduction in cell viability. In contrast, intracellular free calcium chelator, but not of sodium or calcium ion channel blockers, facilitated NaF-induced toxicity in the cells. A JNK specific inhibitor (SP600125) prevented the NaF-induced increase in growth arrest and the DNA damage-inducible protein 45?. Further, NaF-mediated loss of mitochondrial membrane potential was apparently inhibited by pifithrin-? or CAT inhibitor. These findings suggest that NaF affects viability of mESCs in a concentration-dependent manner, where more than 1 mM NaF causes apoptosis through hydroxyl radical-dependent and caspase- and JNK-mediated pathways. -- Highlights: ? The mode of NaF-induced cell death and the mechanisms involved were examined. ? NaF induced mainly apoptotic death of mouse embryonic stem cells (mESCs). ? NaF induced mitochondrial-mediated and caspase-dependent apoptosis. ? JNK- and p53-mediated pathways are involved in NaF-mediated apoptosis in the cells. ? ROS are the up-stream effector in NaF-mediated activation of JNK and p53 in mESCs.

2012-03-15

45

Sodium fluoride induces apoptosis in mouse embryonic stem cells through ROS-dependent and caspase- and JNK-mediated pathways  

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Sodium fluoride (NaF) is used as a source of fluoride ions in diverse applications. Fluoride salt is an effective prophylactic for dental caries and is an essential element required for bone health. However, fluoride is known to cause cytotoxicity in a concentration-dependent manner. Further, no information is available on the effects of NaF on mouse embryonic stem cells (mESCs). We investigated the mode of cell death induced by NaF and the mechanisms involved. NaF treatment greater than 1 mM reduced viability and DNA synthesis in mESCs and induced cell cycle arrest in the G{sub 2}/M phase. The addition of NaF induced cell death mainly by apoptosis rather than necrosis. Catalase (CAT) treatment significantly inhibited the NaF-mediated cell death and also suppressed the NaF-mediated increase in phospho-c-Jun N-terminal kinase (p-JNK) levels. Pre-treatment with SP600125 or z-VAD-fmk significantly attenuated the NaF-mediated reduction in cell viability. In contrast, intracellular free calcium chelator, but not of sodium or calcium ion channel blockers, facilitated NaF-induced toxicity in the cells. A JNK specific inhibitor (SP600125) prevented the NaF-induced increase in growth arrest and the DNA damage-inducible protein 45?. Further, NaF-mediated loss of mitochondrial membrane potential was apparently inhibited by pifithrin-? or CAT inhibitor. These findings suggest that NaF affects viability of mESCs in a concentration-dependent manner, where more than 1 mM NaF causes apoptosis through hydroxyl radical-dependent and caspase- and JNK-mediated pathways. -- Highlights: ? The mode of NaF-induced cell death and the mechanisms involved were examined. ? NaF induced mainly apoptotic death of mouse embryonic stem cells (mESCs). ? NaF induced mitochondrial-mediated and caspase-dependent apoptosis. ? JNK- and p53-mediated pathways are involved in NaF-mediated apoptosis in the cells. ? ROS are the up-stream effector in NaF-mediated activation of JNK and p53 in mESCs.

Nguyen Ngoc, Tam Dan [Institute of Oral Biosciences and School of Dentistry (BK21 Program), Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Son, Young-Ok [Graduate Center for Toxicology, School of Medicine, University of Kentucky, Lexington, KY 40536-0305 (United States); Lim, Shin-Saeng [Institute of Oral Biosciences and School of Dentistry (BK21 Program), Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Department of Bioactive Material Sciences and Research Center of Bioactive Materials, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Shi, Xianglin [Graduate Center for Toxicology, School of Medicine, University of Kentucky, Lexington, KY 40536-0305 (United States); Kim, Jong-Ghee [Institute of Oral Biosciences and School of Dentistry (BK21 Program), Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Heo, Jung Sun [Department of Maxillofacial Biomedical Engineering and Institute of Oral Biology, School of Dentistry, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Choe, Youngji [Institute of Oral Biosciences and School of Dentistry (BK21 Program), Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Jeon, Young-Mi, E-mail: young@jbnu.ac.kr [Institute of Oral Biosciences and School of Dentistry (BK21 Program), Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Lee, Jeong-Chae, E-mail: leejc88@jbnu.ac.kr [Institute of Oral Biosciences and School of Dentistry (BK21 Program), Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Graduate Center for Toxicology, School of Medicine, University of Kentucky, Lexington, KY 40536-0305 (United States); Department of Bioactive Material Sciences and Research Center of Bioactive Materials, Chonbuk National University, Jeonju 561-756 (Korea, Republic of)

2012-03-15

46

TCA Cycle-Mediated Generation of ROS Is a Key Mediator for HeR-MRSA Survival under ?-Lactam Antibiotic Exposure.  

Science.gov (United States)

Methicillin-resistant Staphylococcus aureus (MRSA) is a major multidrug resistant pathogen responsible for several difficult-to-treat infections in humans. Clinical Hetero-resistant (HeR) MRSA strains, mostly associated with persistent infections, are composed of mixed cell populations that contain organisms with low levels of resistance (hetero-resistant HeR) and those that display high levels of drug resistance (homo-resistant HoR). However, the full understanding of ?-lactam-mediated HeR/HoR selection remains to be completed. In previous studies we demonstrated that acquisition of the HoR phenotype during exposure to ?-lactam antibiotics depended on two key elements: (1) activation of the SOS response, a conserved regulatory network in bacteria that is induced in response to DNA damage, resulting in increased mutation rates, and (2) adaptive metabolic changes redirecting HeR-MRSA metabolism to the tricarboxylic acid (TCA) cycle in order to increase the energy supply for cell-wall synthesis. In the present work, we identified that both main mechanistic components are associated through TCA cycle-mediated reactive oxygen species (ROS) production, which temporally affects DNA integrity and triggers activation of the SOS response resulting in enhanced mutagenesis. The present work brings new insights into a role of ROS generation on the development of resistance to ?-lactam antibiotics in a model of natural occurrence, emphasizing the cytoprotective role in HeR-MRSA survival mechanism. PMID:24932751

Rosato, Roberto R; Fernandez, Regina; Paz, Liliana I; Singh, Christopher R; Rosato, Adriana E

2014-01-01

47

TCA Cycle-Mediated Generation of ROS Is a Key Mediator for HeR-MRSA Survival under ?-Lactam Antibiotic Exposure  

Science.gov (United States)

Methicillin-resistant Staphylococcus aureus (MRSA) is a major multidrug resistant pathogen responsible for several difficult-to-treat infections in humans. Clinical Hetero-resistant (HeR) MRSA strains, mostly associated with persistent infections, are composed of mixed cell populations that contain organisms with low levels of resistance (hetero-resistant HeR) and those that display high levels of drug resistance (homo-resistant HoR). However, the full understanding of ?-lactam-mediated HeR/HoR selection remains to be completed. In previous studies we demonstrated that acquisition of the HoR phenotype during exposure to ?-lactam antibiotics depended on two key elements: (1) activation of the SOS response, a conserved regulatory network in bacteria that is induced in response to DNA damage, resulting in increased mutation rates, and (2) adaptive metabolic changes redirecting HeR-MRSA metabolism to the tricarboxylic acid (TCA) cycle in order to increase the energy supply for cell-wall synthesis. In the present work, we identified that both main mechanistic components are associated through TCA cycle-mediated reactive oxygen species (ROS) production, which temporally affects DNA integrity and triggers activation of the SOS response resulting in enhanced mutagenesis. The present work brings new insights into a role of ROS generation on the development of resistance to ?-lactam antibiotics in a model of natural occurrence, emphasizing the cytoprotective role in HeR-MRSA survival mechanism.

Rosato, Roberto R.; Fernandez, Regina; Paz, Liliana I.; Singh, Christopher R.; Rosato, Adriana E.

2014-01-01

48

Withaferin A synergizes the therapeutic effect of doxorubicin through ROS-mediated autophagy in ovarian cancer.  

Science.gov (United States)

Application of doxorubicin (Dox) for the treatment of cancer is restricted due to its severe side effects. We used combination strategy by combining doxorubicin (Dox) with withaferin A (WFA) to minimize the ill effects of Dox. Treatment of various epithelial ovarian cancer cell lines (A2780, A2780/CP70 and CaOV3) with combination of WFA and Dox (WFA/DOX) showed a time- and dose-dependent synergistic effect on inhibition of cell proliferation and induction of cell death, thus reducing the dosage requirement of Dox. Combination treatment resulted in a significant enhancement of ROS production resulting in immense DNA damage, induction of autophagy analyzed by transmission electron microscope and increase in expression of autophagy marker LC3B, and culminated in cell death analyzed by cleaved caspase 3. We validated combination therapy on tumor growth using an in vitro 3Dimension (3D) tumor model and the more classic in vivo xenograft model of ovarian cancer. Both tumor models showed a 70 to 80% reduction in tumor growth compared to control or animals treated with WFA or Dox alone. Immunohistochemical analysis of the tumor tissues from animals treated with WFA/Dox combination showed a significant reduction in cell proliferation and formation of microvessels accompanied by increased in LC3B level, cleaved caspase 3, and DNA damage. Taken together, our data suggest that combining WFA with Dox decreases the dosage requirement of Dox, therefore, minimizing/eliminating the severe side effects associated with high doses of DOX, suggesting the application of this combination strategy for the treatment of ovarian and other cancers with no or minimum side effects. PMID:22860102

Fong, Miranda Y; Jin, Shunying; Rane, Madhavi; Singh, Raj K; Gupta, Ramesh; Kakar, Sham S

2012-01-01

49

Ameliorative effect of acetyl-L-carnitine and/or nifedipine against selenite-induced cataractogenesis in young albino rats.  

Science.gov (United States)

Free radical toxicity and calcium ion overload have been identified as the major two players in the causation of cataract. The current study was carried out to investigate the anti-cataractogenic effect of single and combined treatment with acetyl-l-carnitine and nifedipine in sodium selenite-induced cataract. Rat pups were divided into 5 groups; 1st group received intraperitoneal injection (i.p.) of saline and served as normal control, 2nd group received single subcutaneous injection of sodium selenite 30nmol/g body weight on p10 (postpartum day 10), 3rd and 4th groups received either acetyl-l-carnitine (200mg/kg, i.p.) or nifedipine (0.1mg/kg, i.p.) on p9, respectively, before the administration of sodium selenite, and the treatment continued till p14. Last group received the combined treatments of acetyl-l-carnitine and nifedipine in the same regimen. All animals were examined using a slit lamp and retroillumination then sacrificed on p30. Lenses were removed and processed for biochemical analyses, histopathological and electron microscopic examination. Selenite-treated groups showed significantly (P?0.05) lower values of redox system components (glutathione and glutathione reductase activity) and anti-oxidant enzymes? activities (superoxide dismutase and catalase) along with increased lipid peroxidation that was accompanied by 100% opacified crystalline lenses (mature cataract) with abnormal structure as detected by electron microscopy. It is concluded that acetyl-l-carnitine or nifedipine was able to partially protect against selenite-induced abnormalities. While, combined treatment with acetyl-l-carnitine and nifedipine was superior to individual treatments in slowing down the development of cataract by restoring the anti-oxidant defense and mitigating lipid peroxidation in the lens and hence represents an attractive anti-cataractogenic remedy. PMID:24530554

Farghaly, Lamiaa M; Ghobashy, Waleed A; Shoukry, Youssef; El-Azab, Mona F

2014-04-15

50

Ampelopsin reduces endotoxic inflammation via repressing ROS-mediated activation of PI3K/Akt/NF-?B signaling pathways.  

Science.gov (United States)

Ampelopsin (AMP), a plant flavonoid, has potent anti-inflammatory properties in vitro and in vivo. The molecular mechanisms of ampelopsin on pharmacological and biochemical actions of RAW264.7 macrophages in inflammation have not been clearly elucidated yet. In the present study, non-cytotoxic level of ampelopsin significantly inhibited the release of nitric oxide (NO) and pro-inflammatory cytokines such as interleukin (IL)-1?, IL-6 and tumor necrosis factor (TNF)-? in a dose-dependent manner. Consistent with NO inhibition, ampelopsin suppressed lipopolysaccharide (LPS)-induced expression of inducible NO synthase (iNOS) by inhibiting nuclear factor ?B (NF-?B) activation, which highly correlated with its inhibitory effect on I?B kinase (IKK) phosphorylation, I?B phosphorylation and NF-?B nuclear translocation. Further study demonstrated that ampelopsin suppressed LPS-induced activation of Akt without effecting mitogen-activated protein kinases (MAPKs) phosphorylation. A pharmacological inhibitor of the phosphoinositide 3-kinase (PI3K)-Akt pathway, LY294002, abrogated IKK/I?B/NF-?B-mediated iNOS gene expression. Finally, we certificated that ampelopsin reduced reactive oxygen species (ROS) accumulation and an anti-oxidant N-acetyl-L-cysteine (NAC) significantly repressed LPS-induced PI3K/Akt phosphorylation and the downstream IKK/I?B activation. NAC thereby inhibited LPS-induced iNOS expression and NO production. The present results suggest that the anti-inflammatory effect of ampelopsin is due to inhibiting the interconnected ROS/Akt/IKK/NF-?B signaling pathways. PMID:22193240

Qi, Shimei; Xin, Yinqiang; Guo, Yingtao; Diao, Ying; Kou, Xianjuan; Luo, Lan; Yin, Zhimin

2012-01-01

51

TNF?-induced lysosomal membrane permeability is downstream of MOMP and triggered by caspase-mediated NDUFS1 cleavage and ROS formation.  

Science.gov (United States)

When NF-?B activation or protein synthesis is inhibited, tumor necrosis factor alpha (TNF?) can induce apoptosis through Bax- and Bak-mediated mitochondrial outer membrane permeabilization (MOMP) leading to caspase-3 activation. Additionally, previous studies have implicated lysosomal membrane permeability (LMP) and formation of reactive oxygen species (ROS) as early steps of TNF?-induced apoptosis. However, how these two events connect to MOMP and caspase-3 activation has been largely debated. Here, we present the novel finding that LMP induced by the addition of TNF? plus cycloheximide (CHX), the release of lysosomal cathepsins and ROS formation do not occur upstream but downstream of MOMP and require the caspase-3-mediated cleavage of the p75 NDUFS1 subunit of respiratory complex I. Both a caspase non-cleavable p75 mutant and the mitochondrially localized antioxidant MitoQ prevent LMP mediated by TNF? plus CHX and partially interfere with apoptosis induction. Moreover, LMP is completely blocked in cells deficient in both Bax and Bak, Apaf-1, caspase-9 or both caspase-3 and -7. Thus, after MOMP, active caspase-3 exerts a feedback action on complex I to produce ROS. ROS then provoke LMP, cathepsin release and further caspase activation to amplify TNF? apoptosis signaling. PMID:23788428

Huai, Jisen; Vögtle, F-Nora; Jöckel, Lars; Li, Yunbo; Kiefer, Thomas; Ricci, Jean-Ehrland; Borner, Christoph

2013-09-01

52

Prolonged exposure of cortical neurons to oligomeric amyloid-? impairs NMDA receptor function via NADPH oxidase-mediated ROS production: protective effect of green tea (–-epigallocatechin-3-gallate  

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Full Text Available Excessive production of A? (amyloid ?-peptide has been shown to play an important role in the pathogenesis of AD (Alzheimer's disease. Although not yet well understood, aggregation of A? is known to cause toxicity to neurons. Our recent study demonstrated the ability for oligomeric A? to stimulate the production of ROS (reactive oxygen species in neurons through an NMDA (N-methyl-d-aspartate-dependent pathway. However, whether prolonged exposure of neurons to aggregated A? is associated with impairment of NMDA receptor function has not been extensively investigated. In the present study, we show that prolonged exposure of primary cortical neurons to A? oligomers caused mitochondrial dysfunction, an attenuation of NMDA receptor-mediated Ca2+ influx and inhibition of NMDA-induced AA (arachidonic acid release. Mitochondrial dysfunction and the decrease in NMDA receptor activity due to oligomeric A? are associated with an increase in ROS production. Gp91ds-tat, a specific peptide inhibitor of NADPH oxidase, and Mn(III-tetrakis(4-benzoic acid-porphyrin chloride, an ROS scavenger, effectively abrogated A?-induced ROS production. Furthermore, A?-induced mitochondrial dysfunction, impairment of NMDA Ca2+ influx and ROS production were prevented by pre-treatment of neurons with EGCG [(?-epigallocatechin-3-gallate], a major polyphenolic component of green tea. Taken together, these results support a role for NADPH oxidase-mediated ROS production in the cytotoxic effects of A?, and demonstrate the therapeutic potential of EGCG and other dietary polyphenols in delaying onset or retarding the progression of AD.

Grace Y Sun

2011-02-01

53

PKD is a kinase of Vps34 that mediates ROS-induced autophagy downstream of DAPk.  

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Autophagy, a process in which cellular components are engulfed and degraded within double-membrane vesicles termed autophagosomes, has an important role in the response to oxidative damage. Here we identify a novel cascade of phosphorylation events, involving a network of protein and lipid kinases, as crucial components of the signaling pathways that regulate the induction of autophagy under oxidative stress. Our findings show that both the tumor-suppressor death-associated protein kinase (DAPk) and protein kinase D (PKD), which we previously showed to be phosphorylated and consequently activated by DAPk, mediate the induction of autophagy in response to oxidative damage. Furthermore, we map the position of PKD within the autophagic network to Vps34, a lipid kinase whose function is indispensable for autophagy, and demonstrate that PKD is found in the same molecular complex with Vps34. PKD phosphorylates Vps34, leading to activation of Vps34, phosphatydilinositol-3-phosphate (PI(3)P) formation, and autophagosome formation. Consistent with its identification as a novel inducer of the autophagic machinery, we show that PKD is recruited to LC3-positive autophagosomes, where it localizes specifically to the autophagosomal membranes. Taken together, our results describe PKD as a novel Vps34 kinase that functions as an effecter of autophagy under oxidative stress. PMID:22095288

Eisenberg-Lerner, A; Kimchi, A

2012-05-01

54

ROS-induced epithelial-mesenchymal transition in mammary epithelial cells is mediated by NF-?B-dependent activation of Snail  

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Epithelial-mesenchymal transition (EMT) is characterized by loss of cell-cell junctions, polarity and epithelial markers, and in turn, acquisition of mesenchymal features and motility. Changes associated with this developmental process have been extensively implicated in breast cancer progression and metastasis. Matrix metalloproteinases (MMPs) have been identified as specific inducers of EMT in mammary epithelial cells. MMP-3 induces EMT associated with malignant transformation via a pathway dependent upon production of reactive oxygen species (ROS). While the process by which exposure to MMP-3 leads to induction of ROS has been extensively studied, exactly how the MMP-3-induced ROS stimulate EMT remains unknown. Here, we used profiling methods to identify MMP-3-induced transcriptional alterations in mouse mammary epithelial cells, finding common overlap with changes mediated by nuclear factor-?B (NF-?B) and found in advanced breast cancer. In cultured cells, we found that Snail, an ROS-dependent key mediator of MMP-3-induced changes, is regulated by NF-?B in response to MMP-3. More specifically, we found MMP-3 to cause binding of p65 and cRel NF-?B subunits to the Snail promoter, leading to its transcription. Our results identify a specific pathway by which MMPs induce EMT and malignant characteristics, and provide insight into potential therapeutic approaches to target MMP-associated breast cancers.

Cichon, Magdalena A.; Radisky, Derek C.

2014-01-01

55

Toll-like receptor 4-mediated ROS signaling pathway involved in Ganoderma atrum polysaccharide-induced tumor necrosis factor-? secretion during macrophage activation.  

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Ganoderma atrum has been used as Chinese traditional medicine and healthful mushroom for thousands of years. The polysaccharide is regarded as the major bioactive substances in G. atrum. To delineate the underlying mechanism and signaling cascade involved in the immunomodulatory property of G. atrum polysaccharide (PSG-1). Specifically, this study is designed to examine the possibility of TLR4 as a candidate receptor interacted with G. atrum polysaccharide (PSG-1) and elucidate the role of reactive oxygen species (ROS) in PSG-1-induced tumor necrosis factor-? (TNF-?) production during macrophage activation. Flow cytometric and confocal laser-scanning microscopy analysis showed that fluorescence-labeled PSG-1 bind specifically to the macrophages. Moreover, PSG-1 stimulated TNF-? secretion of peritoneal macrophages from C3H/HeN mice, but not from C3H/HeJ mice. PSG-1-indcued TNF-? production was suppressed by anti-TLR4 mAb. Furthermore, ROS production was mediated by TLR4, and NADPH oxidase-derived ROS act as upstream of phosphoinositide 3-kinase(PI3K)/Akt/mitogen-activated protein kinases(MAPKs)/nuclear factor(NF)-?B signaling pathway in the regulation of PSG-1 stimulated TNF-? production. Taken together, we conclude that PSG-1 induces TNF-? secretion through TLR4/ROS/PI3K/Akt/MAPKs/NF-?B pathways during macrophage activation. Our findings provide a molecular basis for the potential of PSG-1 as a novel immunomodulatory agent. PMID:24447977

Yu, Qiang; Nie, Shao-Ping; Wang, Jun-Qiao; Yin, Peng-Fei; Huang, Dan-Fei; Li, Wen-Juan; Xie, Ming-Yong

2014-04-01

56

Antifilarial effects of polyphenol rich ethanolic extract from the leaves of Azadirachta indica through molecular and biochemical approaches describing reactive oxygen species (ROS) mediated apoptosis of Setaria cervi.  

Science.gov (United States)

Lymphatic filariasis, a global cause of morbidity needs much more attention in developing potent therapeutics that can be effective against both microfilariae (mf) and adults. Efficient botanicals that can induce apoptosis of filarial parasites possibly can provide a direction towards developing new class of antifilarials. In this work we have evaluated the antifilarial efficacy of an optimized polyphenol rich ethanolic extract of Azadirachta indica leaves (EEA). A. indica A. Juss has been widely used in the traditional Indian medicinal system 'Ayurveda' for the treatment of a variety of ailments. A thorough investigation towards biochemical and molecular mechanisms describing ROS mediated apoptosis in Setaria cervi was performed. Motility reduction, MTT reduction assay and dye exclusion test have confirmed the micro- and macrofilaricidal potential of EEA. Alterations were visible in mf and trichrome stained section of EEA-treated adult worms. We have found cellular disturbances in EEA-treated parasites characterized by chromatin condensation, in situ DNA fragmentation and nucleosomal DNA laddering. Depletion in worm GSH level and elevation in parasite GST, SOD, catalase, GPx and superoxide anion indicated the generation of ROS. Our results provided experimental evidence supporting that EEA causes a decreased expression of anti-apoptotic genes and increased pro-apoptotic gene expression at the level of both transcription and translation. Here we are reporting for the first time that antifilarial activity of EEA is mediated by ROS up regulation and apoptosis. PMID:24275557

Mukherjee, Niladri; Mukherjee, Suprabhat; Saini, Prasanta; Roy, Priya; Sinha Babu, Santi P

2014-01-01

57

Mahanine synergistically enhances cytotoxicity of 5-fluorouracil through ROS-mediated activation of PTEN and p53/p73 in colon carcinoma.  

Science.gov (United States)

5-Fluorouracil (5-FU) alone or in combination with other drugs is the main basis of chemotherapeutic treatment in colorectal cancer although patients with microsatellite instability generally show resistance to 5-FU treatment. The present investigation is focussed on the mechanistic insight of a pure herbal carbazole alkaloid, mahanine, as a single or in combination with 5-FU in colon cancer. We demonstrated that mahanine-induced apoptosis involved reactive oxygen species (ROS)-mediated nuclear accumulation of PTEN and its interaction with p53/p73. Mahanine and 5-FU in combination exerted synergistic inhibitory effect on cell viability. This combination also enhanced ROS production, increased tumour suppressor proteins and suppressed chemo-migration. Taken together, our results revealed that mahanine can be a potential chemotherapeutic agent with efficacy to reduce the concentration of toxic 5-FU in colon cancer. PMID:24052409

Das, Ranjita; Bhattacharya, Kaushik; Sarkar, Sayantani; Samanta, Suman Kumar; Pal, Bikas C; Mandal, Chitra

2014-01-01

58

Fisetin inhibits osteoclastogenesis through prevention of RANKL-induced ROS production by Nrf2-mediated up-regulation of phase II antioxidant enzymes.  

Science.gov (United States)

Osteoclasts (OCLs) are multinucleated bone-resorbing cells that are differentiated by stimulation with receptor activator of nuclear factor kappa-B ligand (RANKL) and macrophage colony-stimulating factor. We recently demonstrated that regulation of heme-oxygenase 1 (HO-1), a stress-induced cytoprotective enzyme, also functions in OCL differentiation. In this study, we investigated effects of fisetin, a natural bioactive flavonoid that has been reported to induce HO-1 expression, on the differentiation of macrophages into OCLs. Fisetin inhibited the formation of OCLs in a dose-dependent manner and suppressed the bone-resorbing activity of OCLs. Moreover, fisetin-treated OCLs showed markedly decreased phosphorylation of extracellular signal-regulated kinase, Akt, and Jun N-terminal kinase, but fisetin did not inhibit p38 phosphorylation. Fisetin up-regulated mRNA expression of phase II antioxidant enzymes including HO-1 and interfered with RANKL-mediated reactive oxygen species (ROS) production. Studies with RNA interference showed that suppression of NF-E2-related factor 2 (Nrf2), a key transcription factor for phase II antioxidant enzymes, rescued fisetin-mediated inhibition of OCL differentiation. Furthermore, fisetin significantly decreased RANKL-induced nuclear translocation of cFos and nuclear factor of activated T cells cytoplasmic-1 (NFATc1), which is a transcription factor critical for osteoclastogenic gene regulation. Therefore, fisetin inhibits OCL differentiation through blocking RANKL-mediated ROS production by Nrf2-mediated up-regulation of phase II antioxidant enzymes. PMID:23538677

Sakai, Eiko; Shimada-Sugawara, Megumi; Yamaguchi, Yu; Sakamoto, Hiroshi; Fumimoto, Reiko; Fukuma, Yutaka; Nishishita, Kazuhisa; Okamoto, Kuniaki; Tsukuba, Takayuki

2013-01-01

59

Hyperketonemia induces upregulation of LFA-1 in monocytes, which is mediated by ROS and P38 MAPK activation.  

Science.gov (United States)

Type 1 diabetic patients have hyperketonemia, elevated levels of pro-inflammatory and oxidative stress markers, and a higher incidence of vascular disease. This study examines the hypothesis that hyperketonemia increases reactive oxygen species (ROS) and is in part responsible for increased expression of adhesion molecules in monocytes. THP-1 monocytes were treated with acetoacetate (AA) or ?-hydroxybutyrate (BHB) (0-10 mmol/L) for 24 h. Results show that AA, but not BHB, increases ROS production in monocytes. Pretreatment of monocytes with N-acetylcysteine (NAC) inhibited AA-induced ROS production. AA treatment induced upregulation of LFA-1 and pretreatment of monocytes with NAC or an inhibitor to p38 MAPK inhibited this upregulation in monocytes. This suggests that physiological concentrations of AA can contribute to increased ROS and activation of p38 MAPK, which may be responsible for AA-induced upregulation of LFA-1 in monocytes. Thus, hyperketonemia contributes to the risk for cardiovascular disease in type 1 diabetes. PMID:23210443

Rains, Justin L; Kanikarla-Marie, Preeti; Jain, Sushil K

2012-12-01

60

NADPH oxidase-mitochondria axis-derived ROS mediate arsenite-induced HIF-1? stabilization by inhibiting prolyl hydroxylases activity.  

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Arsenic exposure has been shown to induce hypoxia inducible factor 1? (HIF-1?) accumulation, however the underlying mechanism remains unknown. In the present study, we tested the hypothesis that arsenic exposure triggered the interaction between NADPH oxidase and mitochondria to promote reactive oxygen species (ROS) production, which inactivate prolyl hydroxylases (PHDs) activity, leading to the stabilization of HIF-1? protein. Exposure of human immortalized liver cell line HL-7702 cells to arsenite induced HIF-1? accumulation in a dose-dependent manner, which was abolished by SOD mimetic MnTMPyP. Inhibition of NADPH oxidase with diphenyleneiodonium chloride (DPI) or inhibition of mitochondrial respiratory chain with rotenone significantly blocked arsenite-induced ROS production, and the mitochondria appeared to be the major source of ROS production. Arsenite treatment inhibited HIF-1? hydroxylation by prolyl hydroxylases (PHDs) and increased HIF-1? stabilization, but did not affect HIF-1? mRNA expression and Akt activation. Supplementation of ascorbate or Fe(II) completely abolished arsenite-induced PHDs inhibition and HIF-1? stabilization. In conclusion, these results define a unique mechanism of HIF-1? accumulation following arsenic exposure, that is, arsenic activates NADPH oxidase-mitochondria axis to produce ROS, which deplete intracellular ascorbate and Fe(II) to inactivate PHDs, leading to HIF-1? stabilization. PMID:24188932

Li, Ying-Na; Xi, Miao-Miao; Guo, Yu; Hai, Chun-Xu; Yang, Wei-Lin; Qin, Xu-Jun

2014-01-13

 
 
 
 
61

Natural borneol, a monoterpenoid compound, potentiates selenocystine-induced apoptosis in human hepatocellular carcinoma cells by enhancement of cellular uptake and activation of ROS-mediated DNA damage.  

Science.gov (United States)

Selenocystine (SeC) has been identified as a novel compound with broad-spectrum anticancer activities. Natural borneol (NB) is a monoterpenoid compound that has been used as a promoter of drug absorption. In the present study, we demonstrated that NB significantly enhanced the cellular uptake of SeC and potentiated its antiproliferative activity on HepG2 cells by induction of apoptosis. NB effectively synergized with SeC to reduce cancer cell growth through the triggering apoptotic cell death. Further mechanistic studies by Western blotting showed that treatment of the cells with NB and SeC activated the intrinsic apoptotic pathway by regulation of pro-survival and pro-apoptotic Bcl-2 family proteins. Treatment of the cells with NB and SeC induced the activation of p38MAPK and inactivation of Akt and ERK. NB also potentiated SeC to trigger intracellular ROS generation and DNA strand breaks as examined by Comet assay. Moreover, the thiol-reducing antioxidants effectively blocked the occurrence of cell apoptosis, which confirmed the important role of ROS in cell apoptosis. Taken together, these results reveal that NB strongly potentiates SeC-induced apoptosis in cancer cells by enhancement of cellular uptake and activation of ROS-mediated DNA damage. NB could be further developed as a chemosensitizer of SeC in treatment of human cancers. PMID:23700426

Su, Jianyu; Lai, Haoqiang; Chen, Jianping; Li, Lin; Wong, Yum-Shing; Chen, Tianfeng; Li, Xiaoling

2013-01-01

62

Oleanolic acid arrests cell cycle and induces apoptosis via ROS-mediated mitochondrial depolarization and lysosomal membrane permeabilization in human pancreatic cancer cells.  

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Oleanolic acid (OA), a pentacyclic triterpenoid, exhibits potential anti-tumor activity against many tumor cell lines. This study aims to examine the anti-tumor activity of OA on pancreatic cancer cells and its potential molecular mechanism. The results showed that the proliferation of Panc-28 cells was inhibited by OA in a concentration-dependent manner, with an IC50 (The half maximal inhibitory concentration) value of 46.35?µg ml(-1) , as determined by MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. The cell cycle was arrested in S phase and G2/M phase by OA. The study also showed that OA could induce remarkable apoptosis, evidenced by an increased percentage of early/late apoptotic cells, DNA ladder and nuclear morphology change. Further study revealed that OA could induce Reactive Oxygen Species (ROS) generation, mitochondrial depolarization, release of cytochrome C, lysosomal membrane permeabilization and leakage of cathepin B. The expression of apoptosis-correlated proteins was also affected in cells treated with OA, including activation of caspases-3/9 and cleavage of PARP. Further study confirmed that ROS scavenger vitamin C could reverse the apoptosis induced by OA in Panc-28 cells. Our results provide evidence that OA arrests the cell cycle and induces apoptosis, possibly via ROS-mediated mitochondrial and a lysosomal pathway in Panc-28 cells. PMID:22678527

Wei, Jianteng; Liu, Ming; Liu, Haizhou; Wang, Hui; Wang, Fengxia; Zhang, Yuyan; Han, Lijun; Lin, Xiukun

2013-08-01

63

Hydrogen sulfide prevents OGD/R-induced apoptosis via improving mitochondrial dysfunction and suppressing an ROS-mediated caspase-3 pathway in cortical neurons.  

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Hydrogen sulfide (H2S), an endogenous gaseous mediator, has been shown to have protective effects against neuronal damage caused by brain ischemia. In this study, we explored the potential effects of H2S on oxygen-glucose deprivation/reoxygenation (OGD/R)-induced neuronal apoptosis and the possible mechanisms. We find that sodium hydrosulfide (NaHS, a donator of H2S) prevents OGD/R-induced intracellular reactive oxygen species (ROS) elevation and activation of caspase-3 in cultured mouse cortical neurons. The pretreatment of N-acetyl-l-cysteine (NAC, an ROS scavenger) also prevents OGD/R-induced activation of caspase-3. Both NaHS and NAC counteract OGD/R-induced decline in mitochondria membrane potential (MMP). Additionally, NaHS, NAC or N-Acetyl-Asp-Glu-Val-Asp-CHO (DEVD-CHO, a caspase-3 inhibitor), is shown to significantly inhibit OGD/R-induced neuronal apoptosis. These data suggest that H2S can protect against OGD/R-induced neuronal apoptosis through improving mitochondria dysfunction and suppressing an ROS-activated caspase-3 signaling pathway. PMID:23770272

Luo, Yougen; Yang, Xifei; Zhao, Shenting; Wei, Churong; Yin, Yedong; Liu, Ting; Jiang, Sainv; Xie, Jiajun; Wan, Xiaomei; Mao, Muhua; Wu, Jiyun

2013-12-01

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Grape-Derived Polyphenols Prevent Doxorubicin-Induced Blunted EDH-Mediated Relaxations in the Rat Mesenteric Artery: Role of ROS and Angiotensin II  

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This study determined whether doxorubicin, an anticancer agent, impairs endothelium-dependent relaxations mediated by nitric oxide (NO) and endothelium-derived hyperpolarization (EDH) in the mesenteric artery and, if so, the mechanism underlying the protective effect of red wine polyphenols (RWPs), a rich natural source of antioxidants. Male Wistar rats were assigned into 4 groups: control, RWPs, doxorubicin, and doxorubicin + RWPs. Vascular reactivity was assessed in organ chambers; the vascular formation of reactive oxygen species (ROS) using dihydroethidine and the expression levels of small and intermediate conductance calcium-activated potassium channels (SKCa, IKCa) and connexin 40 (Cx40), which are involved in EDH-type relaxations, endothelial NO synthase (eNOS), angiotensin II, and AT1 receptors by immunofluorescence. The doxorubicin treatment impaired EDH-mediated relaxations, whereas those mediated by NO were minimally affected. This effect was associated with reduced expression levels of SKCa, IKCa, and Cx40, increased expression levels of eNOS, angiotensin II, and AT1 receptors, and formation of ROS in mesenteric arteries. RWPs prevented both the doxorubicin-induced blunted EDH-type relaxations and the increased vascular oxidative stress, and they improved the expression levels of target proteins. These findings suggest that polyphenol-rich natural products might be of interest in the management of doxorubicin-induced vascular injury possibly by improving the vascular angiotensin system.

Idris-Khodja, Noureddine; Di Marco, Paola; Farhat, Mona; Geny, Bernard; Schini-Kerth, Valerie B.

2013-01-01

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Snake venom toxin from vipera lebetina turanica induces apoptosis of colon cancer cells via upregulation of ROS- and JNK-mediated death receptor expression  

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Full Text Available Abstract Background Abundant research suggested that the cancer cells avoid destruction by the immune system through down-regulation or mutation of death receptors. Therefore, it is very important that finding the agents that increase the death receptors of cancer cells. In this study, we demonstrated that the snake venom toxin from Vipera lebetina turanica induce the apoptosis of colon cancer cells through reactive oxygen species (ROS and c-Jun N-terminal kinases (JNK dependent death receptor (DR4 and DR5 expression. Methods We used cell viability assays, DAPI/TUNEL assays, as well as western blot for detection of apoptosis related proteins and DRs to demonstrate that snake venom toxin-induced apoptosis is DR4 and DR5 dependent. We carried out transient siRNA knockdowns of DR4 and DR5 in colon cancer cells. Results We showed that snake venom toxin inhibited growth of colon cancer cells through induction of apoptosis. We also showed that the expression of DR4 and DR5 was increased by treatment of snake venom toxin. Moreover, knockdown of DR4 or DR5 reversed the effect of snake venom toxin. Snake venom toxin also induced JNK phosphorylation and ROS generation, however, pretreatment of JNK inhibitor and ROS scavenger reversed the inhibitory effect of snake venom toxin on cancer cell proliferation, and reduced the snake venom toxin-induced upregulation of DR4 and DR5 expression. Conclusions Our results indicated that snake venom toxin could inhibit human colon cancer cell growth, and these effects may be related to ROS and JNK mediated activation of death receptor (DR4 and DR5 signals.

Park Mi

2012-06-01

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Pardaxin, an Antimicrobial Peptide, Triggers Caspase-Dependent and ROS-Mediated Apoptosis in HT-1080 Cells  

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Full Text Available Pardaxin is an antimicrobial peptide (AMP that was first isolated from secretions of the Red Sea Moses sole. The role of pardaxin in inducing apoptosis for preventing cancer has not yet been investigated. In the present study, we examined the antitumor activity of pardaxin against human fibrosarcoma HT-1080 cells; pardaxin inhibited cell proliferation by inducing apoptosis, as demonstrated by an increase in the externalization of plasma membrane phosphatidylserine and the presence of chromatin condensation. Additionally, pardaxin-treated cells showed elevation of caspase-3/7 activities, disruption of the mitochondrial membrane potential, and accumulation of reactive oxygen species (ROS production. Inhibition of ROS production and caspase-3/7 activities reduced pardaxin-induced effects. Taken together, these findings suggest that pardaxin may be a potential anticancer agent for selectively inducing apoptosis in cancer cells.

Tsui-Chin Huang

2011-10-01

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Indomethacin sensitizes TRAIL-resistant melanoma cells to TRAIL-induced apoptosis through ROS-mediated upregulation of death receptor 5 and downregulation of survivin.  

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Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has attracted considerable attention owing to its selective killing of tumor cells but not normal cells. Melanoma shows weak response to TRAIL because of its low level of TRAIL death receptors. Here, we investigated whether indomethacin, a nonsteroidal anti-inflammatory drug, can potentiate TRAIL-induced apoptosis in melanoma cells. We showed that indomethacin was capable of promoting TRAIL-induced cell death and apoptosis in A375 melanoma cells. Mechanistically, indomethacin induced cell surface expression of death receptor 5 (DR5) in melanoma cells and also in various types of cancer cells. DR5 knockdown abolished the enhancing effect of indomethacin on TRAIL responses. Induction of the DR5 by indomethacin was found to be p53 independent but dependent on the induction of CCAAT/enhancer-binding protein homologous protein (CHOP). Knockdown of CHOP abolished indomethacin-induced DR5 expression and the associated potentiation of TRAIL-mediated cell death. In addition, indomethacin-induced reactive oxygen species (ROS) production preceded upregulation of CHOP and DR5, and consequent sensitization of cells to TRAIL. We also found that indomethacin treatment downregulated survivin via ROS and the NF-?B-mediated signaling pathways. Interestingly, indomethacin also converted TRAIL-resistant melanoma MeWo and SK-MEL-5 cells into TRAIL-sensitive cells. Taken together, our results indicate that indomethacin can potentiate TRAIL-induced apoptosis through upregulation of death receptors and downregulation of survivin. PMID:24213373

Tse, Anfernee Kai-Wing; Cao, Hui-Hui; Cheng, Chi-Yan; Kwan, Hiu-Yee; Yu, Hua; Fong, Wang-Fun; Yu, Zhi-Ling

2014-05-01

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Ebselen induces reactive oxygen species (ROS)-mediated cytotoxicity in Saccharomyces cerevisiae with inhibition of glutamate dehydrogenase being a target.  

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Ebselen is a synthetic, lipid-soluble seleno-organic compound. The high electrophilicity of ebselen enables it to react with multiple cysteine residues of various proteins. Despite extensive research on ebselen, its target molecules and mechanism of action remains less understood. We performed biochemical as well as in vivo experiments employing budding yeast as a model organism to understand the mode of action of ebselen. The growth curve analysis and FACS (florescence activated cell sorting) assays revealed that ebselen exerts growth inhibitory effects on yeast cells by causing a delay in cell cycle progression. We observed that ebselen exposure causes an increase in intracellular ROS levels and mitochondrial membrane potential, and that these effects were reversed by addition of antioxidants such as reduced glutathione (GSH) or N-acetyl-l-cysteine (NAC). Interestingly, a significant increase in ROS levels was noticed in gdh3-deleted cells compared to wild-type cells. Furthermore, we showed that ebselen inhibits GDH function by interacting with its cysteine residues, leading to the formation of inactive hexameric GDH. Two-dimensional gel electrophoresis revealed protein targets of ebselen including CPR1, the yeast homolog of Cyclophilin A. Additionally, ebselen treatment leads to the inhibition of yeast sporulation. These results indicate a novel direct connection between ebselen and redox homeostasis. PMID:24490132

Azad, Gajendra Kumar; Singh, Vikash; Mandal, Papita; Singh, Prabhat; Golla, Upendarrao; Baranwal, Shivani; Chauhan, Sakshi; Tomar, Raghuvir S

2014-01-01

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Ebselen induces reactive oxygen species (ROS)-mediated cytotoxicity in Saccharomyces cerevisiae with inhibition of glutamate dehydrogenase being a target?  

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Ebselen is a synthetic, lipid-soluble seleno-organic compound. The high electrophilicity of ebselen enables it to react with multiple cysteine residues of various proteins. Despite extensive research on ebselen, its target molecules and mechanism of action remains less understood. We performed biochemical as well as in vivo experiments employing budding yeast as a model organism to understand the mode of action of ebselen. The growth curve analysis and FACS (florescence activated cell sorting) assays revealed that ebselen exerts growth inhibitory effects on yeast cells by causing a delay in cell cycle progression. We observed that ebselen exposure causes an increase in intracellular ROS levels and mitochondrial membrane potential, and that these effects were reversed by addition of antioxidants such as reduced glutathione (GSH) or N-acetyl-l-cysteine (NAC). Interestingly, a significant increase in ROS levels was noticed in gdh3-deleted cells compared to wild-type cells. Furthermore, we showed that ebselen inhibits GDH function by interacting with its cysteine residues, leading to the formation of inactive hexameric GDH. Two-dimensional gel electrophoresis revealed protein targets of ebselen including CPR1, the yeast homolog of Cyclophilin A. Additionally, ebselen treatment leads to the inhibition of yeast sporulation. These results indicate a novel direct connection between ebselen and redox homeostasis.

Azad, Gajendra Kumar; Singh, Vikash; Mandal, Papita; Singh, Prabhat; Golla, Upendarrao; Baranwal, Shivani; Chauhan, Sakshi; Tomar, Raghuvir S.

2014-01-01

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Wogonin enhances antitumor activity of tumor necrosis factor-related apoptosis-inducing ligand in vivo through ROS-mediated downregulation of cFLIPL and IAP proteins.  

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Combination of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) with other agents is a promising strategy to overcome TRAIL resistance in malignant cells. Wogonin, a flavonoid originated from Scutellaria baicalensis Georgi, has been shown to enhance TRAIL-induced apoptosis in malignant cells in in vitro studies. However, whether wogonin enhances TRAIL's antitumor activity in vivo has never been studied. In this study, the effect of combination of TRAIL and wogonin was tested in a non-small-cell lung cancer xenografted tumor model in nude mice. Consistent with the in vitro study showing that wogonin sensitized A549 cells to TRAIL-induced apoptosis, wogonin greatly enhanced TRAIL-induced suppression of tumor growth, accompanied with increased apoptosis in tumor tissues as determined by TUNEL assay. The expression levels of antiapoptotic proteins including long form of cellular FLICE-like inhibitory protein (cFLIPL), X-linked inhibitor of apoptosis protein (XIAP), and cellular inhibitor of apoptosis protein 1 and 2 (cIAP-1 and cIAP-2) were markedly reduced in both cultured cells and xenografted tumor tissues after co-treatment with wogonin and TRAIL. The down-regulation of these antiapoptotic proteins was likely mediated by proteasomal degradation that involved intracellular reactive oxygen species (ROS), because wogonin robustly induced ROS accumulation and ROS scavengers butylated hydroxyanisole (BHA) and N-acetyl-L-cysteine (NAC) and the proteasome inhibitor MG132 restored the expression of these antiapoptotic proteins in cells co-treated with wogonin and TRAIL. These results show for the first time that wogonin enhances TRAIL's antitumor activity in vivo, suggesting this strategy has an application potential for clinical anticancer therapy. PMID:23371323

Yang, Lan; Wang, Qiong; Li, Daoxia; Zhou, Yuqiong; Zheng, Xuelian; Sun, Hong; Yan, Jiaqi; Zhang, Lin; Lin, Yong; Wang, Xia

2013-05-01

71

Quinazoline analog HMJ-30 inhibits angiogenesis: Involvement of endothelial cell apoptosis through ROS-JNK-mediated death receptor 5 signaling.  

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The aim of the present study was to explore the effect of 6-fluoro-2-(3-fluorophenyl)-4-(cyanoanilino) quinazoline (HMJ-30) on the anti-angiogenic properties and apoptosis-related mechanism of human umbilical vein endothelial cells (HUVECs). In this study, HMJ-30 dose- and time-dependently inhibited the viability of HUVECs. We also found that HMJ-30 enhanced disruption of tube-like structures and suppressed cell migration in HUVECs after vascular endothelial growth factor (VEGF) induction. HMJ-30 was also observed to inhibit vessel branching and sprouting in chicken chorioallantoic membrane (CAM). Microsprouting induced by VEGF in the rat aortic ring and blood vessel formation in a mouse Matrigel plug were individually suppressed by HMJ-30. In an in vitro study, HMJ-30 induced the apoptotic death of HUVECs as indicated by DNA fragmentation and promoted reactive oxygen species (ROS) production as determined by flow cytometric assay. In addition, extrinsic caspase signaling (caspase-8 and -3) was activated in the HMJ-30-treated HUVECs and their inhibitors were applied to assess the signal transduction. We investigated the upstream of the death receptor pathway and further observed that the levels of death receptor 5 (DR5) and phosphorylated c-Jun N-terminal kinase (JNK) signals were upregulated in HUVECs following HMJ-30 challenge, which was confirmed by a JNK-specific inhibitor (SP600125). Hence, HMJ-30-induced endothelial cell apoptosis involved the ROS/JNK-regulated DR5 pathway. In summary, HMJ-30 may provide a potential therapeutic effect for the anti-vascular targeting of angiogenesis during cancer treatment. PMID:24919794

Lu, Chi-Cheng; Chen, Hao-Ping; Chiang, Jo-Hua; Jin, Yi-An; Kuo, Sheng-Chu; Wu, Tian-Shung; Hour, Mann-Jen; Yang, Jai-Sing; Chiu, Yu-Jen

2014-08-01

72

Xanthorrhizol induces apoptosis through ROS-mediated MAPK activation in human oral squamous cell carcinoma cells and inhibits DMBA-induced oral carcinogenesis in hamsters.  

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Xanthorrhizol, a natural sesquiterpenoid compound isolated from Curcuma xanthorrhiza Roxb, has been known to inhibit the growth of human colon, breast, liver and cervical cancer cells. In this study, xanthorrhizol decreased cell viability, induced apoptosis and decreased the level of full-length PARP in SCC-15 oral squamous cell carcinoma (OSCC) cells. A decrease in cell viability and PARP degradation was not prevented by treatment with the caspase inhibitor Z-VAD-fmk in xanthorrhizol-treated cells. Xanthorrhizol treatment elevated intracellular Ca(2+) and ROS levels in SCC-15 cells. Treatment with a Ca(2+) chelator, EGTA/AM, did not affect xanthorrhizol- induced cytotoxicity, but cell viability was partly recovered by treatment with endogenous antioxidant, GSH, or hydroxy radical trapper, MCI-186. Furthermore, the viability of xanthorrhizol-treated SCC-15 cells was significantly restored by treatment with SB203580 and/or SP600125 but not significantly by PD98059 treatment. Xanthorrhizol-induced activation of p38 MAPK and JNK was blocked by MCI-186. Finally, xanthorrhizol suppressed the number of tumors in buccal pouches and increased the survival rate in hamsters treated with 7,12-dimethylbenz[a]anthracene. In conclusion, xanthorrhizol may induce caspase-independent apoptosis through ROS-mediated p38 MAPK and JNK activation in SCC-15 OSCC cells and prevent chemical-induced oral carcinogenesis. Therefore, xanthorrhizol seems to be a promising chemopreventive agent. PMID:22627996

Kim, Ju Yeon; An, Jeong Mi; Chung, Won-Yoon; Park, Kwang-Kyun; Hwang, Jae Kwan; Kim, Du Sik; Seo, Su Ryeon; Seo, Jeong Taeg

2013-04-01

73

8?-hydroxy-3-oxopimar-15-ene exerts anti-inflammatory effects by inhibiting ROS-mediated activation of the TRAF6-ASK1-p38 signaling pathway.  

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The flying squirrel's droppings (Pteropus pselaphon) have been used for improving the blood circulation, arresting bleeding to treat hematological disorders, and reducing pain. Here, 8?-hydroxy-3-oxopimar-15-ene (OXO), one of main constituents of P. pselaphon, was examined for its anti-inflammatory activity in murine macrophages. We found that OXO significantly suppressed LPS-induced nitric oxide (NO) without exerting cytotoxic effects on RAW 264.7 cells. OXO inhibited the expression of LPS-induced iNOS and COX-2 protein and their mRNA in a dose-dependent manner. Also, TNF-?, IL-6, and PGE2 secretion was decreased by OXO in LPS-stimulated macrophages. These inflammatory biomarkers were attributed to the suppression of LPS-induced activation of p38 MAPK and subsequent activation of two components of AP-1 (c-Jun and c-Fos), but not of ERK, JNK, NF-?B. Moreover, OXO inhibited LPS-induced intracellular reactive oxygen species (ROS) production and co-incubation of OXO and hydrogen peroxide (H2O2) suppressed the phosphorylation of p38 in a concentration-dependent manner. In addition, OXO completely disrupted the formation of TRAF6-ASK complex in the cells. Therefore, we demonstrate here that OXO can potentially inhibit several biomarkers related to inflammation through inhibition of ROS-mediated activation of TRAF6-ASK1-p38 pathway. PMID:23914844

Cho, Jae-Heung; Lee, Jong Hyun; Lee, Eun-Jung; Nam, Dongwoo; Shim, Bum Sang; Song, Mi-Yeon; Kim, Sung-Soo; Kim, Sung-Hoon; Jung, Sang Hoon; Chung, Won-Seok; Ahn, Kwang Seok

2013-10-01

74

SFE-CO2 Extract from Typhonium giganteum Engl. Tubers, Induces Apoptosis in Human Hepatoma SMMC-7721 Cells Involvement of a ROS-Mediated Mitochondrial Pathway  

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Full Text Available Typhonium giganteum Engl. (BaiFuzi is one of the herbs commonly used in traditional Chinese medicine against cancer. In our previous studies, 37 compounds were identified the SFE-CO2 (supercritical fluid extraction with CO2 extract by GC-MS, including the four major components [?-sitosterol (40.22%, campesterol (18.45%, n-hexadecanoic acid (9.52% and (Z,Z-9,12-octadecadienoic acid (8.15%]. The anti-cancer mechanisms of the SFE-CO2 extract from T. giganteum Engl. tubers have not been reported as yet. In this paper, the molecular mechanisms of the SFE-CO2 extract-mediated apoptosis in SMMC-7721 cells were further examined. SFE-CO2 extract inhibited the growth of SMMC-7721 cells in a time- and dose-dependent manner, arrested the cell cycle in the S phase and G2/M phase, and induced apoptosis. In addition, reactive oxygen species (ROS increase, reduction of mitochondrial membrane potential, a rise in intracellular calcium levels were found in SMMC-7721 cells after treated with the extract. Western blot analysis showed that the extract caused down-regulation of Bcl-2 expression, and up-regulation of Bax expression. Moreover, caspase-3 and caspase-9 protease activity significantly increased in a dose-dependent manner. Collectively, our results showed that the SFE-CO2 extract from T. giganteum Engl. tubers induces apoptosis in SMMC-7721 cells involving a ROS-mediated mitochondrial signalling pathway.

Li Zhang

2011-09-01

75

Coumestrol suppresses hypoxia inducible factor 1? by inhibiting ROS mediated sphingosine kinase 1 in hypoxic PC-3 prostate cancer cells.  

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Among many signals to regulate hypoxia inducible factor 1? (HIF-1?), sphingosine kinase 1 (SPHK1) is also involved in various biological activities such as cell growth, survival, invasion, angiogenesis, and carcinogenesis. Thus, in the present study, molecular mechanisms of coumestrol were investigated on the SPHK1 and HIF-1? signaling pathway in hypoxic PC-3 prostate cancer cells. Coumestrol significantly suppressed SPHK1 activity and accumulation of HIF-1? in a time- and concentration-dependent manner in hypoxic PC-3 cells. In addition, coumestrol inhibited the phosphorylation status of AKT and glycogen synthase kinase-3? (GSK 3?) signaling involved in cancer metabolism. Furthermore, SPHK1 siRNA transfection, sphigosine kinase inhibitor (SKI), reactive oxygen species (ROS) enhanced the inhibitory effect of coumestrol on the accumulation of HIF-1? and the expression of pAKT and pGSK 3? in hypoxic PC-3 cells by combination index. Overall, our findings suggest that coumestrol suppresses the accumulation of HIF-1? via suppression of SPHK1 pathway in hypoxic PC-3 cells. PMID:24768446

Cho, Sung-Yun; Cho, Sunmi; Park, Eunkyung; Kim, Bonglee; Sohn, Eun Jung; Oh, Bumsuk; Lee, Eun-Ok; Lee, Hyo-Jeong; Kim, Sung-Hoon

2014-06-01

76

Prevention of selenite-induced cataractogenesis by an ethanolic extract of Cineraria maritima: an experimental evaluation of the traditional eye medication.  

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In the present study, the antioxidant potential of an ethanolic extract of Cineraria maritima and its efficacy in preventing selenite-induced cataractogenesis were assessed in vitro and in vivo. In the in vitro phase of the study, lenses dissected out from the eyes of Wistar rats were incubated for 24 h at 37 °C in Dulbecco's modified Eagle medium (DMEM) alone (group I), in DMEM containing 100 ?M of selenite only (group II), or in DMEM containing 100 ?M of selenite and 300 ?g/ml C. maritima extract added at the same time (group III). Gross morphological examination of the lenses revealed dense opacification in group II, minimal opacification in group III, and no opacification in group I lenses. The mean activities of the antioxidant enzymes catalase, glutathione peroxidase, and superoxide dismutase were significantly lower in group II than in group I or group III lenses, while malondialdehyde concentration was significantly higher in group II lenses than in group I and group III lenses. In the in vivo phase of the study, dense opacification of lenses was noted in all rat pups (100%) that had received a single subcutaneous injection of sodium selenite alone (19 ?M/kg body weight) on postpartum day 10, whereas cataract formation occurred in only 33.3% of rat pups that had received selenite as well as an intraperitoneal injection of the extract of C. maritima (350 mg/kg body weight) for five consecutive days. These observations suggest that the ethanolic extract of C. maritima may prevent experimental selenite-induced cataractogenesis. PMID:20949376

Anitha, Thirugnanasambandhar Sivasubramanian; Annadurai, Thangaraj; Thomas, Philip A; Geraldine, Pitchairaj

2011-10-01

77

Cajanol, a novel anticancer agent from Pigeonpea [Cajanus cajan (L.) Millsp.] roots, induces apoptosis in human breast cancer cells through a ROS-mediated mitochondrial pathway.  

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Cajanol (5-hydroxy-3-(4-hydroxy-2-methoxyphenyl)-7-methoxychroman-4-one) is an isoflavanone from Pigeonpea [Cajanus cajan (L.) Millsp.] roots. As the most effective phytoalexin in pigeonpea, the cytotoxic activity of cajanol towards cancer cells has not been report as yet. In the present study, the anticancer activity of cajanol towards MCF-7 human breast cancer cells was investigated. In order to explore the underlying mechanism of cell growth inhibition of cajanol, cell cycle distribution, DNA fragmentation assay and morphological assessment of nuclear change, ROS generation, mitochondrial membrane potential (DeltaPsim) disruption, and expression of caspase-3 and caspase-9, Bax, Bcl-2, PARP and cytochrome c were measured in MCF-7 cells. Cajanol inhibited the growth of MCF-7 cells in a time and dose-dependent manner. The IC(50) value was 54.05 microM after 72 h treatment, 58.32 microM after 48 h; and 83.42 microM after 24h. Cajanol arrested the cell cycle in the G2/M phase and induced apoptosis via a ROS-mediated mitochondria-dependent pathway. Western blot analysis showed that cajanol inhibited Bcl-2 expression and induced Bax expression to desintegrate the outer mitochondrial membrane and causing cytochrome c release. Mitochondrial cytochrome c release was associated with the activation of caspase-9 and caspase-3 cascade, and active-caspase-3 was involved in PARP cleavage. All of these signal transduction pathways are involved in initiating apoptosis. To the best of our knowledge, this is the first report demonstrating the cytotoxic activity of cajanol towards cancer cells in vitro. PMID:20638373

Luo, Meng; Liu, Xia; Zu, Yuangang; Fu, Yujie; Zhang, Su; Yao, Liping; Efferth, Thomas

2010-10-01

78

Induction of miR-21-PDCD4 signaling by tungsten carbide-cobalt nanoparticles in JB6 cells involves ROS-mediated MAPK pathways.  

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Tungsten carbide-cobalt (WC-Co) nanoparticle composites have wide applications because of their hardness and toughness. WC-Co was classified as "probably carcinogenic" to humans by the International Agency for Research on Cancer (IARC) in 2003. It is believed that the toxicity and carcinogenesis of WC-Co is associated with particle size. Recent studies demonstrated that the tumor suppressor gene programmed cell death 4 (PDCD4) and its upstream regulator miR-21 have been considered as oncogenes for novel cancer prevention or anticancer therapies. The present study examined the effects of WC-Co nanoparticles on miR-21-PDCD4 signaling in a mouse epidermal cell line (JB6 P+). The results showed that (i) exposure of JB6 cells to WC-Co stimulated a increase of miR-21 generation; (ii) WC-Co also caused inhibition of PDCD4, a tumor suppressor protein and downstream target of miR-21, expression in JB6 cells; (iii) inhibition of ERKs with ERK inhibitor U0126 significantly reversed WC-Cominus;induced PDCD4 inhibition, but inhibition of p38 with p38 inhibitor SB203580 did not; and (iv) ROS scavengers, N-acetyl-L-cysteine and catalase, blocked the inhibitory effect of WC-Co on PDCD4 expression, while superoxide dismutase promoted the inhibitory effect. These findings demonstrate that WC-Co nanoparticles induce miR-21 generation, but inhibit PDCD4 production, which may be mediated through ROS, especially endogenous H2O2, and ERK pathways. Unraveling the complex mechanisms associated with these events may provide insights into the initiation and progression of WC-Co-induced carcinogenesis. PMID:23758151

Hou, Lichao; Bowman, Linda; Meighan, Terence G; Shi, Xianglin; Ding, Min

2013-01-01

79

(?)-Epigallocatechin-3-Gallate Induces Non-Apoptotic Cell Death in Human Cancer Cells via ROS-Mediated Lysosomal Membrane Permeabilization  

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(?)-Epigallocatechin-3-gallate (EGCG) is the most extensive studied tea polyphenol for its anti-cancer function. In this study, we report a novel mechanism of action for EGCG-mediated cell death by identifying the critical role of lysosomal membrane permeabilization (LMP). First, EGCG-induced cell death in human cancer cells (both HepG2 and HeLa) was found to be caspase-independent and accompanied by evident cytosolic vacuolization, only observable when cells were treated in serum-free medi...

Zhang, Yin; Yang, Nai-di; Zhou, Fan; Shen, Ting; Duan, Ting; Zhou, Jing; Shi, Yin; Zhu, Xin-qiang; Shen, Han-ming

2012-01-01

80

Induction of ROS-dependent mitochondria-mediated intrinsic apoptosis in MDA-MB-231 cells by glycoprotein from Codium decorticatum.  

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Marine macroalgae consist of a range of bioactive molecules exhibiting different biological activities, and many of these properties are attributed to sulfated polysaccharides, fucoxanthin, phycobiliproteins, and halogenated compounds. In this study, a glycoprotein (GLP) with a molecular mass of ?48 kDa was extracted and purified from Codium decorticatum and investigated for its cytotoxic properties against human MDA-MB-231 breast cancer cells. The IC?? values of GLP against MDA-MB-231 and normal breast HBL-100 cells (control) were 75 ± 0.23 ?g/mL (IC??), 55 ± 0.32 ?g/mL (IC??), and 30 ± 0.43 ?g/mL (IC??) and 90 ± 0.57 ?g/mL (IC??), 80 ± 0.48 ?g/mL (IC??), and 60 ± 0.26 ?g/mL (IC??), respectively. Chromatin condensation and poly(ADP-ribose) polymerase (PARP) cleavage studies showed that the GLP inhibited cell viability by inducing apoptosis in MDA-MB-231 cells. Induction of mitochondria-mediated intrinsic apoptotic pathway by GLP was evidenced by the events of loss of mitochondrial membrane potential (??(m)), bax/bcl-2 dysregulation, cytochrome c release, and activation of caspases 3 and 9. Apoptosis-associated factors such as reactive oxygen species (ROS) formation and loss of ??(m) were evaluated by DCFH-DA staining and flow cytometry, respectively. Cell cycle arrest of G?/M phase and expression of apoptosis associated proteins were determined using flow cytometry and Western blotting, respectively. PMID:24694116

Thangam, Ramar; Senthilkumar, Dharmaraj; Suresh, Veeraperumal; Sathuvan, Malairaj; Sivasubramanian, Srinivasan; Pazhanichamy, Kalailingam; Gorlagunta, Praveen Kumar; Kannan, Soundarapandian; Gunasekaran, Palani; Rengasamy, Ramasamy; Sivaraman, Jayanthi

2014-04-16

 
 
 
 
81

Quercetin enhances apoptotic effect of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in ovarian cancer cells through reactive oxygen species (ROS) mediated CCAAT enhancer-binding protein homologous protein (CHOP)-death receptor 5 pathway.  

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Although tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has shown efficacy in a phase 2 clinical trial, development of resistance to TRAIL by tumor cells is a major roadblock. We investigated whether quercetin, a flavonoid, can sensitize human ovarian cancer cells to TRAIL. Results indicate that quercetin sensitized cancer cells to TRAIL. The quercetin induced expression of death receptor DR5 but did not affect expression of DR4 in cancer cells. The induction of DR5 was mediated through activation of JNK and through upregulation of a transcription factor CCAAT enhancer-binding protein homologous protein (CHOP); as silencing of these signaling molecules abrogated the effect of quercetin. Upregulation of DR5 was mediated through the generation of reactive oxygen species (ROS), as ROS scavengers reduced the effect of quercetin on JNK activation, CHOP upregulation, DR induction, TRAIL sensitization, downregulated the expression of cell survival proteins and upregulated the proapoptotic proteins. Furthermore, quercetin enhances TRAIL mediated inhibition of tumor growth of human SKOV-3 xenograft was associated with induction of apoptosis, activation of caspase-3, CHOP and DR5. Overall, our data suggest that quercetin enhances apoptotic death of ovarian cancer cells to TRAIL through upregulation of CHOP-induced DR5 expression following ROS mediated endoplasmic reticulum-stress. PMID:24612139

Yi, Liu; Zongyuan, Yang; Cheng, Gong; Lingyun, Zhang; Guilian, Yu; Wei, Gong

2014-05-01

82

Chaetocin-induced ROS-mediated apoptosis involves ATM-YAP1 axis and JNK-dependent inhibition of glucose metabolism.  

Science.gov (United States)

Oxidative stress serves as an important regulator of both apoptosis and metabolic reprogramming in tumor cells. Chaetocin, a histone methyltransferase inhibitor, is known to induce ROS generation. As elevating basal ROS level sensitizes glioma cells to apoptosis, the ability of Chaetocin in regulating apoptotic and metabolic adaptive responses in glioma was investigated. Chaetocin induced glioma cell apoptosis in a ROS-dependent manner. Increased intracellular ROS induced (i) Yes-associated protein 1 (YAP1) expression independent of the canonical Hippo pathway as well as (ii) ATM and JNK activation. Increased interaction of YAP1 with p73 and p300 induced apoptosis in an ATM-dependent manner. Chaetocin induced JNK modulated several metabolic parameters like glucose uptake, lactate production, ATP generation, and activity of glycolytic enzymes hexokinase and pyruvate kinase. However, JNK had no effect on ATM or YAP1 expression. Coherent with the in vitro findings, Chaetocin reduced tumor burden in heterotypic xenograft glioma mouse model. Chaetocin-treated tumors exhibited heightened ROS, pATM, YAP1 and pJNK levels. Our study highlights the coordinated control of glioma cell proliferation and metabolism by ROS through (i) ATM-YAP1-driven apoptotic pathway and (ii) JNK-regulated metabolic adaptation. The elucidation of these newfound connections and the roles played by ROS to simultaneously shift metabolic program and induce apoptosis could provide insights toward the development of new anti-glioma strategies. PMID:24810048

Dixit, D; Ghildiyal, R; Anto, N P; Sen, E

2014-01-01

83

Localizing NADPH Oxidase-Derived ROS  

Science.gov (United States)

Reactive oxygen species (ROS) function as signaling molecules to mediate various biological responses, including cell migration, growth, and gene expression. ROS are diffusible and short-lived molecules. Thus, localizing the ROS signal at the specific subcellular compartment is essential for activating redox signaling events after receptor activation. NADPH (nicotinamide adenine dinucleotide phosphate) oxidase is one of the major sources of ROS in vasculature; it consists of a catalytic subunit (Nox1, Nox2, Nox3, Nox4, or Nox5), p22phox, p47phox, p67phox, and the small guanosine triphosphatase Rac1. Targeting of NADPH oxidase to focal complexes in lamellipodia and membrane ruffles through the interaction of p47phox with the scaffold proteins TRAF4 and WAVE1 provides a mechanism for achieving localized ROS production, which is required for directed cell migration. ROS are believed to inactivate protein tyrosine phosphatases, which concentrate in specific subcellular compartments, thereby establishing a positive feedback system that activates redox signaling pathways to promote cell movement. Additionally, ROS production may be localized through interactions of NADPH oxidase with signaling platforms associated with lipid rafts and caveolae, as well as with endosomes. There is also evidence that NADPH oxidase is found in the nucleus, indicating its involvement in redox-responsive gene expression. This review focuses on targeting of NADPH oxidase to discrete subcellular compartments as a mechanism of localizing ROS and activation of downstream redox signaling events that mediate various cell functions.

Masuko Ushio-Fukai (IL;University of Illinois College of Medicine, Chicago REV)

2006-08-22

84

Reactive oxygen species (ROS) by p66Shc longevity protein mediate non-genomic androgen action via tyrosine phosphorylation signaling to enhance tumorigenicity of prostate cancer cells  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Steroid hormones exhibit diverse biological activities. Despite intensive studies on steroid function at the genomic level, their non-genomic action remains an enigma. In this study, we investigated the role of reactive oxygen species (ROS) in androgen-stimulated prostate cancer (PCa) cell proliferation. In androgen-treated PCa cells, increased cell growth and ROS production correlated with elevated p66Shc protein, an authentic oxidase. This growth stimulation was blocked by anti-oxidants. Fu...

Veeramani, Suresh; Chou, Yu-wei; Lin, Frank C.; Muniyan, Sakthivel; Lin, Fen-fen; Kumar, Satyendra; Xie, Yan; Lele, Subodh M.; Tu, Yaping; Lina, Ming-fong

2012-01-01

85

Activation of Autophagy Protects Against ROS-Mediated Mitochondria-Dependent Apoptosis in L-02 Hepatocytes Induced by Cr(VI).  

Science.gov (United States)

Background: Hexavalent chromium (Cr(VI)) overdose causes hepatocellular injuries by inducing mitochondrial damage and subsequent apoptosis in animals and humans. Autophagy can selectively remove damaged organelles, especially impaired mitochondria, and in turn, protects against mitochondria-dependent cell death. The present study was designed to explore the effects of autophagy on the Cr(VI)-induced hepatotoxicity. Methods: L-02 hepatocytes were incubated with different concentrations of Cr(VI) for 24h and several indicators for evaluating mitochondrial damage and hepatocellular apoptosis were measured. Then effects of ROS scavenger NAC on ROS production and calcium overload during Cr(VI)-induced hepatotoxicity were examined. Finally, the study further investigated the role of autophagy played in repairing mitochondrial damage and subsequent hepatocyte injuries. Results: After exposed to different concentrations of Cr(VI) for 24h, cell viability, mitochondria membrane potential, ATP content were significantly decreased and caspase-3 activities and apoptosis rates increased in L-02 hepatocytes. The treatment of NAC reduced ROS formation and Ca(2+) content, restored CRAC channel activities and further diminished mitochondrial injuries. Furthermore, autophagy inducer, rapamycin is beneficial for repairing mitochondrial function and limiting hepatocytes damage, and pharmacological inhibition of autophagy by 3-methyladenine further exacerbated Cr(VI)-induced hepatotoxicity. Conclusions: ROS production is a critical reason for Cr(VI)-induced mitochondria-dependent apoptosis. And activation of autophagy could repair mitochondria function to protect hepatocytes potentially by removing damaged mitochondria. © 2014 S. Karger AG, Basel. PMID:24643125

Xie, Ying; Xiao, Fang; Luo, Lei; Zhong, Caigao

2014-01-01

86

Thioredoxin-ASK1 complex levels regulate ROS-mediated p38 MAPK pathway activity in livers of aged and long-lived Snell dwarf mice.  

Science.gov (United States)

We have proposed that the age-associated increase of reactive oxygen species (ROS) by electron transport chain (ETC) dysfunction may cause the elevated basal level of p38 MAPK stress response pathway activity. However, the mechanism by which ROS activates this pathway is not clear. Here we propose that activation of the p38 MAPK pathway by complex I (CI) generated ROS, in response to rotenone (ROT) treatment, is based on the ability of reduced Trx to bind to and inhibit ASK 1 and its release from the complex upon oxidation. This balance of free vs. bound ASK1 regulates the level of p38 MAPK pathway activity. To support this mechanism we demonstrate that the production of ROS by ROT treated AML12 hepatocyte cells dissociates the Trx-ASK1 complex, thereby increasing p38 MAPK pathway activity. This mechanism is supported by the ability of N-acetyl cysteine (NAC) to prevent dissociation of Trx-ASK1 and activation of the p38 MAPK pathway. We also demonstrated that the ratio of ASK1/Trx-ASK1 increases in aged mouse livers and that this correlates with the increased basal activity of the p38 MAPK pathway. The longevity of Snell dwarf mice has been attributed to their resistance to oxidative stress. A comparison of the levels of Trx-ASK1 in young and aged dwarfs showed a higher abundance of the complex than in their age-matched controls. These results, which are indicative of a decreased level of oxidative stress, suggest that increased ROS production in aged liver may alter the ratio of ASK1 and Trx-ASK1, thereby increasing the age-associated basal level of p38 MAPK pathway activity. PMID:16449798

Hsieh, Ching-Chyuan; Papaconstantinou, John

2006-02-01

87

Mobile robot navigation with ROS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

These slides give an overview of the current navigation functionalities available in ROS. The content is used as an introduction during the ROS navigation tutorial that is part of the IPA ROS industrial seminar.

Bubeck, Alexander

2013-01-01

88

Snake venom toxin from vipera lebetina turanica induces apoptosis of colon cancer cells via upregulation of ROS- and JNK-mediated death receptor expression  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract Background Abundant research suggested that the cancer cells avoid destruction by the immune system through down-regulation or mutation of death receptors. Therefore, it is very important that finding the agents that increase the death receptors of cancer cells. In this study, we demonstrated that the snake venom toxin from Vipera lebetina turanica induce the apoptosis of colon cancer cells through reactive oxygen species (ROS) and c-Jun N-terminal kinases (...

Park Mi; Jo MiRan; Won Dohee; Song Ho; Han Sang; Song Min; Hong Jin

2012-01-01

89

Nitric oxide signals ROS scavenger-mediated enhancement of PAL activity in nitrogen-deficient Matricaria chamomilla roots: side effects of scavengers.  

Science.gov (United States)

Owing to the abundance of phenolic metabolites in plant tissue, their accumulation represents an important tool for stress protection. However, the regulation of phenolic metabolism is still poorly known. The regulatory role of reactive oxygen species (ROS) in the activity of phenylalanine ammonia-lyase (PAL) in nitrogen (N)-deficient chamomile roots treated for 24 h was studied using three ROS scavengers [dithiothreitol (DTT), salicylhydroxamic acid, and sodium benzoate]. Scavengers decreased the level of hydrogen peroxide and/or superoxide (and up-regulated ascorbate/guaiacol peroxidase and glutathione reductase), but, surprisingly, stimulated PAL activity. This up-regulation was correlated with increases in nitric oxide (NO) content, total soluble phenols, selected phenolic acids, and, partially, lignin (being expressed the most in DTT-exposed roots). We therefore tested the hypothesis that NO may be involved in these changes. Application of 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO) decreased PAL activity and the accumulation of soluble phenols in all treatments. Exogenous H(2)O(2) and NO also stimulated PAL activity and the accumulation of phenols. We conclude that NO, in addition to hydrogen peroxide, may regulate PAL activity during N deficiency. The anomalous effect of PTIO on NO content and possible mechanism of ROS scavenger-evoked NO increases in light of the current knowledge are also discussed. PMID:19345259

Kovácik, Jozef; Klejdus, Borivoj; Backor, Martin

2009-06-15

90

ROS-Mediated Autophagy Induced by Dysregulation of Lipid Metabolism Plays a Protective Role in Colorectal Cancer Cells Treated with Gambogic Acid  

Science.gov (United States)

Gambogic acid (GA), the main active component of gamboge resin, has potent antitumor activity both in vivo and in vitro. However, the underlying molecular mechanisms remain unclear. In this study, we found that GA could initiate autophagy in colorectal cancer cells, and inhibition of the autophagy process accelerated the effect of proliferative inhibition and apoptotic cell death induced by GA, implying a protective role of autophagy. Two-dimensional electrophoresis-based proteomics showed that GA treatment altered the expression of multiple proteins involved in redox signaling and lipid metabolism. Functional studies revealed that GA-induced dysregulation of lipid metabolism could activate 5-lipoxygenase (5-LOX), resulting in intracellular ROS accumulation, followed by inhibition of Akt-mTOR signaling and autophagy initiation. Finally, results using a xenograft model suggested ROS-induced autophagy protect against the antitumor effect of GA. Taken together, these data showed new biological activities of GA against colorectal cancer underlying the protective role of ROS-induced autophagy. This study will provide valuable insights for future studies regarding the anticancer mechanisms of GA.

Zhang, Haiyuan; Lei, Yunlong; Yuan, Ping; Li, Lingjun; Luo, Chao; Gao, Rui; Tian, Jun; Feng, Zuohua; Nice, Edouard C.; Sun, Jun

2014-01-01

91

Application development with ROS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

What is being established in research already is going to be standardized and adopted by industry. The open source "Robot Operating System" ROS offers highly developed robotics software components which can be used in flexible industrial applications.

Weißhardt, Florian

2013-01-01

92

Reactive oxygen species (ROS) by p66Shc longevity protein mediate non-genomic androgen action via tyrosine phosphorylation signaling to enhance tumorigenicity of prostate cancer cells  

Science.gov (United States)

Steroid hormones exhibit diverse biological activities. Despite intensive studies on steroid function at the genomic level, their non-genomic action remains an enigma. In this study, we investigated the role of reactive oxygen species (ROS) in androgen-stimulated prostate cancer (PCa) cell proliferation. In androgen-treated PCa cells, increased cell growth and ROS production correlated with elevated p66Shc protein, an authentic oxidase. This growth stimulation was blocked by anti-oxidants. Further, elevated expression of p66Shc protein by cDNA transfection encoding wild type (WT) protein, but not redox-deficient (W134F) mutant, was associated with increased PCa cell proliferation. Conversely, knockdown p66Shc expression by shRNA resulted in diminished cell growth. Increased p66Shc expression in PCa cells enhanced their tumorigenicity in xenograft animals. Importantly, p66Shc protein level is higher in clinical prostate adenocarcinomas than in adjacent non-cancerous cells. Expression of redox-deficient p66Shc mutant protein abolished androgen-stimulated cell growth. In androgen-treated, H2O2-treated and p66Shc cDNA-transfected PCa cells, cellular prostatic acid phosphatase (cPAcP), an authentic tyrosine phosphatase, was inactivated by reversible oxidation; subsequently, ErbB-2 was activated by phosphorylation at tyrosine1221/2. These results together support the notion that androgens induce ROS production through the elevation of p66Shc protein, which inactivates tyrosine phosphatase activity for the activation of interacting tyrosine kinase, leading to increased cell proliferation and enhanced tumorigenicity. Our results thus suggest that p66Shc protein functions at the critical junction point between androgens and tyrosine phosphorylation signaling in human PCa cells.

Veeramani, Suresh; Chou, Yu-Wei; Lin, Frank C.; Muniyan, Sakthivel; Lin, Fen-Fen; Kumar, Satyendra; Xie, Yan; Lele, Subodh M; Tu, Yaping; Lina, Ming-Fong

2012-01-01

93

Lipophilic Compound-Mediated Gene Expression and Implication for Intervention in Reactive Oxygen Species (ROS-Related Diseases: Mini-review  

Directory of Open Access Journals (Sweden)

Full Text Available In addition to exhibiting antioxidant properties, conjugated linoleic acid (CLA and vitamin E may modulate gene expression of endogenous antioxidant enzymes. Depending on cellular microenvironments, such modulation reflects either antioxidant or prooxidant outcomes. Although epidemiological/experimental studies have indicated that CLA and vitamin E have health promoting properties, recent findings from clinical trials have been inconclusive. Discrepancies between the results found from prospective studies and recent clinical trials might be attributed to concentration-dependent cellular microenvironment alterations. We give a perspective of possible molecular mechanisms of actions of these lipophilic compounds and their implications for interventions of reactive oxygen species (ROS-related diseases.

Yukiko K. Nakamura

2010-07-01

94

A Chinese Herbal Decoction, Modified Yi Guan Jian, Induces Apoptosis in Hepatic Stellate Cells through an ROS-Mediated Mitochondrial/Caspase Pathway.  

Science.gov (United States)

The Chinese herb modified Yi Guan Jian (mYGJ) is an effective regimen that is usually used in outpatients with chronic liver diseases such as fibrosis and cirrhosis. However, the mechanism for the action of mYGJ on liver fibrosis is not yet clear. In this study, we found that mYGJ induced hepatic stellate cells (HSCs) apoptosis concomitant with the downregulation of Bcl-2 expression and slight elevation of Bax level. Moreover, the reactive oxygen species (ROS) were generated in the early stages of mYGJ-induced HSCs apoptosis to facilitate calcium and cytochrome c release from the mitochondria to cytosol. Subsequently, caspase 9 and caspase 3 were activated. Furthermore, the activation of ER stress-associated caspase 12 in HSCs was also evaluated. Together, we report the first evidence-based study to demonstrate that mYGJ decoction induces HSCs apoptosis through ROS accumulation and the intrinsic apoptosis pathway. These findings provide rationale for further clinical investigation of traditional Chinese medicine recipes against liver fibrosis. PMID:20976079

Lin, Hung-Jen; Tseng, Ching-Ping; Lin, Chia-Fan; Liao, Mei-Huei; Chen, Chuan-Mu; Kao, Shung-Te; Cheng, Ju-Chien

2011-01-01

95

Radiation-induced apoptosis of neural precursors cell cultures: early modulation of the response mediated by reactive oxygen and nitrogen species (ROS/RNS)  

International Nuclear Information System (INIS)

Apoptosis, the typical mode of radiation-induced cell death in developing Central Nervous System (CNS), is closely related with the oxidative status. Enhanced radiation-induced generation of ROS/RNS has been observed after exposures to low radiation doses leading to cellular amplification of signal transduction and further molecular and cellular radiation-responses. Moreover Nitric oxide (NO) and hydroxyl radical are implicated in dopaminergic neurotoxicity in different parading. This study is an attempt to address the participation of radiation-induced free radicals production, the contribution of endogenous NO generation, and the excitonic pathway, in the radiation-induced apoptosis of neural cortical precursors. Cortical cells obtained from at 17 gestational day (gd) were irradiated with doses from 0,2 Gy to 2 Gy at a dose-rate of 0.3 Gy/m. A significant decrease of Luminol-dependent Chemiluminescence was evident 30 m after irradiation reaching basal levels at 120 m follow for a tendency to increasing values Incubations with Superoxide Dismatuse (SOD) decreased significantly the chemiluminescence in irradiated samples NO content estimated by measuring the stable products NO2 and NO3 released to the culture medium in the same period, has shown a time-dependent accumulation from 1 h post-irradiation. the apoptosis, determined 24 h post-irradiation by flow cytometry, morphology and DNA fragmentation revealed a dose-effect relationship with significant differences from 0.4 Gy. The samples pre-treated with 10 mM of N-acetyl cysteine (NAC) a precursor of intracellular GSH synthesis, shown a significant decrease of the apoptosis. Apoptosis was significantly increased in irradiated cells after inhibition of nitric oxide synthase (NOS) byL-NAME. We conclude that ROS/RNS play a pivotal role in the early signaling pathways leading to a radiation-induced cell death. (Author) 40 refs

2004-01-01

96

ROS Installation and Commissioning  

CERN Multimedia

The ATLAS Readout group (a sub-group of TDAQ) has now completed the installation and commissioning of all of the Readout System (ROS) units. Event data from ATLAS is initially handled by detector specific hardware and software, but following a Level 1 Accept the data passes from the detector specific Readout Drivers (RODs) to the ROS, the first stage of the central ATLAS DAQ. Within the final ATLAS TDAQ system the ROS stores the data and on request makes it available to the Level 2 Trigger (L2) processors and to the Event Builder (EB) as required. The ROS is implemented as a large number of PCs housing custom built cards (ROBINs) and running custom multi-threaded software. Each ROBIN card (shown below) contains buffer memories to store the data, plus a field programmable gate array ( FPGA ) and an embedded PowerPC processor for management of the memories and data requests, and is implemented as a 64-bit 66 MHz PCI card. Both the software and the ROBIN cards have been designed and developed by the Readout g...

Gorini, B

97

Role of c-Met/phosphatidylinositol 3-kinase (PI3k)/Akt signaling in hepatocyte growth factor (HGF)-mediated lamellipodia formation, reactive oxygen species (ROS) generation, and motility of lung endothelial cells.  

Science.gov (United States)

Hepatocyte growth factor (HGF) mediated signaling promotes cell proliferation and migration in a variety of cell types and plays a key role in tumorigenesis. As cell migration is important to angiogenesis, we characterized HGF-mediated effects on the formation of lamellipodia, a pre-requisite for migration using human lung microvascular endothelial cells (HLMVECs). HGF, in a dose-dependent manner, induced c-Met phosphorylation (Tyr-1234/1235, Tyr-1349, Ser-985, Tyr-1003, and Tyr-1313), activation of PI3k (phospho-Yp85) and Akt (phospho-Thr-308 and phospho-Ser-473) and potentiated lamellipodia formation and HLMVEC migration. Inhibition of c-Met kinase by SU11274 significantly attenuated c-Met, PI3k, and Akt phosphorylation, suppressed lamellipodia formation and endothelial cell migration. LY294002, an inhibitor of PI3k, abolished HGF-induced PI3k (Tyr-458), and Akt (Thr-308 and Ser-473) phosphorylation and suppressed lamellipodia formation. Furthermore, HGF stimulated p47(phox)/Cortactin/Rac1 translocation to lamellipodia and ROS generation. Moreover, inhibition of c-Met/PI3k/Akt signaling axis and NADPH oxidase attenuated HGF- induced lamellipodia formation, ROS generation and cell migration. Ex vivo experiments with mouse aortic rings revealed a role for c-Met signaling in HGF-induced sprouting and lamellipodia formation. Taken together, these data provide evidence in support of a significant role for HGF-induced c-Met/PI3k/Akt signaling and NADPH oxidase activation in lamellipodia formation and motility of lung endothelial cells. PMID:24634221

Usatyuk, Peter V; Fu, Panfeng; Mohan, Vijay; Epshtein, Yulia; Jacobson, Jeffrey R; Gomez-Cambronero, Julian; Wary, Kishore K; Bindokas, Vytas; Dudek, Steven M; Salgia, Ravi; Garcia, Joe G N; Natarajan, Viswanathan

2014-05-01

98

The ROS Workshop  

CERN Multimedia

The first week of February saw the taking place of the ReadOut Subsystem (ROS) workshop. The ROS is the subsystem of the Trigger, DAQ & DCS project which receives and buffers data from the detector ReadOut Drivers (RODs). On request it then provides a subset of this buffered data, the so-called Regions of Interest (RoI), to the Level 2 trigger. Using the subsequent Level 2 trigger decision, the ROS either removes the buffered event data from its buffers or sends the full event data to the Event Filter for further processing. The workshop took place over a four-day period at a location in the Jura. The average daily attendance was twenty people, which mainly represented the five main ATLAS institutes currently engaged in this Trigger, DAQ & DCS activity. The aim of the workshop was to bring to an end the current prototyping activities in this area and launch the next, final, phase of prototyping. This new phase of prototyping will build on the successful activities of the previous phase and will focus...

Francis, D.

99

?-Caryophyllene oxide inhibits growth and induces apoptosis through the suppression of PI3K/AKT/mTOR/S6K1 pathways and ROS-mediated MAPKs activation.  

Science.gov (United States)

Both PI3K/AKT/mTOR/S6K1 and mitogen activated protein kinase (MAPK) signaling cascades play an important role in cell proliferation, survival, angiogenesis, and metastasis of tumor cells. In the present report, we investigated the effects of ?-caryophyllene oxide (CPO), a sesquiterpene isolated from essential oils of medicinal plants such as guava (Psidium guajava), oregano (Origanum vulgare L.), cinnamon (Cinnamomum spp.) clove (Eugenia caryophyllata), and black pepper (Piper nigrum L.) on the PI3K/AKT/mTOR/S6K1 and MAPK activation pathways in human prostate and breast cancer cells. We found that CPO not only inhibited the constitutive activation of PI3K/AKT/mTOR/S6K1 signaling cascade; but also caused the activation of ERK, JNK, and p38 MAPK in tumor cells. CPO induced increased reactive oxygen species (ROS) generation from mitochondria, which is associated with the induction of apoptosis as characterized by positive Annexin V binding and TUNEL staining, loss of mitochondrial membrane potential, release of cytochrome c, activation of caspase-3, and cleavage of PARP. Inhibition of ROS generation by N-acetylcysteine (NAC) significantly prevented CPO-induced apoptosis. Subsequently, CPO also down-regulated the expression of various downstream gene products that mediate cell proliferation (cyclin D1), survival (bcl-2, bcl-xL, survivin, IAP-1, and IAP-2), metastasis (COX-2), angiogenesis (VEGF), and increased the expression of p53 and p21. Interestingly, we also observed that CPO can significantly potentiate the apoptotic effects of various pharmacological PI3K/AKT inhibitors when employed in combination in tumor cells. Overall, these findings suggest that CPO can interfere with multiple signaling cascades involved in tumorigenesis and used as a potential therapeutic candidate for both the prevention and treatment of cancer. PMID:21924548

Park, Kyung-Ran; Nam, Dongwoo; Yun, Hyung-Mun; Lee, Seok-Geun; Jang, Hyeung-Jin; Sethi, Gautam; Cho, Somi K; Ahn, Kwang Seok

2011-12-22

100

Intracellular ROS Scavenging Activity and Downregulation of Inflammatory Mediators in RAW264.7 Macrophage by Fresh Leaf Extracts of Pseuderanthemum palatiferum.  

Science.gov (United States)

Beneficial antioxidant phytochemicals are found in many medicinal plants. Pseuderanthemum palatiferum (PP), a well-known Vietnamese traditional medicinal plant in Thailand, has long been used in folk medicine for curing inflammatory diseases, often with limited support of scientific research. Therefore, this study aimed to determine antioxidant and modulation of inflammatory mediators of ethanol and water extracts of PP (EEP and WEP, resp.). WEP had significantly higher phenolic and flavonoid levels and DPPH radical scavenging activity than EEP. However, EEP exhibited greater reducing power than WEP. A greater decrease of tert-butyl hydroperoxide-induced oxidative stress in RAW264.7 macrophage cells was also observed with EEP. Modulation of inflammatory mediators of EEP and WEP was evaluated on LPS plus IFN- ? -stimulated RAW264.7 cells. EEP more potently suppressed LPS plus IFN- ? -induced nitric oxide (NO) production than WEP. Both EEP and WEP also suppressed the expression of iNOS and COX-2 protein levels. Collectively, these results suggest that PP possesses strong antioxidant and anti-inflammatory properties. PMID:24744809

Sittisart, Patcharawan; Chitsomboon, Benjamart

2014-01-01

 
 
 
 
101

Sensitization of cancer cells to radiation by selenadiazole derivatives by regulation of ROS-mediated DNA damage and ERK and AKT pathways.  

Science.gov (United States)

X-ray-based radiotherapy represents one of the most effective ways in treating human cancers. However, radioresistance and side effect remain as the most challenging issue. This study describes the design and application of novel selenadiazole derivatives as radiotherapy sensitizers to enhance X-ray-induced inhibitory effects on A375 human melanoma and Hela human cervical carcinoma cells. The results showed that, pretreatment of the cells with selenadiazole derivatives dramatically enhance X-ray-induced growth inhibition and colony formation. Flow cytometry analysis indicates that the sensitization by selenadiazole derivatives was mainly caused by induction of G2/M cell cycle arrest. Results of Western blotting demonstrated that the combined treatment-induced A375 cells growth inhibition was achieved by triggering reactive oxygen species-mediated DNA damage involving inactivation of AKT and MAPKs. Further investigation revealed that selenadiazole derivative in combination with X-ray could synergistically inhibit the activity of thioredoxin reductase-1 in A375 cells. Taken together, these results suggest that selenadiazole derivatives can act as novel radiosensitizer with potential application in combating human cancers. PMID:24813998

Xie, Qiang; Zhou, Yangliang; Lan, Guoqiang; Yang, Liye; Zheng, Wenjie; Liang, Yuanwei; Chen, Tianfeng

2014-06-20

102

Biological evaluation of new nickel(II) metallates: Synthesis, DNA/protein binding and mitochondrial mediated apoptosis in human lung cancer cells (A549) via ROS hypergeneration and depletion of cellular antioxidant pool.  

Science.gov (United States)

A series of novel nickel(II) thiosemicarbazone complexes(1-4) have been prepared and characterized by various spectral, analytical techniques and X-ray crystallography. Further, their efficacy to interact with CT-DNA/BSA has been explored. From the binding studies, it is inferred that complex 4 found to be more active than other complexes. The complexes bound with CT-DNA by intercalation mode. Moreover, static quenching was observed for their interaction with BSA. The new complexes were tested for their in vitro cytotoxicity against human lung adenocarcinoma (A549) cell line. The results showed that the new complexes exhibited significant degree of cytotoxicity at given experimental condition. Further, the results of LDH and NO release supported the cytotoxic nature of the complexes. The observed cytotoxicity of the complexes may be routed through ROS-hypergeneration and lipid-peroxidation with subsequent depletion of cellular antioxidant pool (GSH, SOD, CAT, GPx and GST) resulted in the reduction of mitochondrial-membrane potential, caspase-3 activation and DNA fragmentation. Thus, the data from the present study disclose that the complexes could induce apoptosis in A549 cells through mitochondrial mediated fashion and inhibited the migration of lung cancer cells and by metastasis. PMID:24946146

Kalaivani, P; Saranya, S; Poornima, P; Prabhakaran, R; Dallemer, F; Vijaya Padma, V; Natarajan, K

2014-07-23

103

Effects of temperature on complexes I and II mediated respiration, ROS generation and oxidative stress status in isolated gill mitochondria of the mud crab Scylla serrata.  

Science.gov (United States)

Effects of fluctuations in habitat temperature (18-30°) on mitochondrial respiratory behavior and oxidative metabolic responses in the euryhaline ectotherm Scylla serrata are not fully understood. In the present study, effects of different temperatures ranging from 12 to 40°C on glutamate and succinate mediated mitochondrial respiration, respiratory control ratio (RCR), ATP generation rate, ratio for the utilization of phosphate molecules per atomic oxygen consumption (P/O), levels of lipid peroxidation and H2O2 in isolated gill mitochondria of S. serrata are reported. The pattern of variation in the studied parameters was similar for the two substrates at different temperatures. The values recorded for RCR (?3) and P/O ratio (1.4-2.7) at the temperature range of 15-25°C were within the normal range reported for other animals (3-10 for RCR and 1.5-3 for P/O). Values for P/O ratio, ATP generation rate and RCR were highest at 18°C when compared to the other assay temperatures. However, at low and high extreme temperatures, i.e. at 12 and 40°C, states III and IV respiration rates were not clearly distinguishable from each other indicating that mitochondria were completely uncoupled. Positive correlations were noticed between temperature and the levels of both lipid peroxidation and H2O2. It is inferred that fluctuations on either side of ambient habitat temperature may adversely influence mitochondrial respiration and oxidative metabolism in S. serrata. The results provide baseline data to understand the impacts of acute changes in temperature on ectotherms inhabiting estuarine or marine environments. PMID:24679979

Paital, Biswaranjan; Chainy, G B N

2014-04-01

104

Sending ROS on a Bullet Train  

Science.gov (United States)

Plants have to contend with biotic stress, such as disease, mechanical wounding, and herbivory, as well as abiotic stress, such as heat, cold, and salinity. An early warning system for these threats would prevent or reduce the damage suffered by plants. Such a warning system should allow the signal to be rapidly generated and sent over long distances. The study of systemic signaling in plants has been a major scientific challenge. Reactive oxygen species (ROS) are among the systemic signals that have been proposed. Now, the exciting discovery that systemic ROS signaling is mediated by an NADPH (nicotinamide adenine dinucleotide phosphate, reduced form) oxidase opens the door to understanding the molecular mechanisms that initiate and propagate a rapid systemic signal.

Hann Ling Wong (Japan;Nara Institute of Science and Technology REV); Ko Shimamoto (Japan;Nara Institute of Science and Technology REV)

2009-09-29

105

ROS and Phytohormones in Plant-Plant Allelopathic Interaction  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Allelopathy refers to plant-plant interference mediated mostly by plant released products of secondary metabolism. It was recently suggested that allelochamicals may influence growth of neighboring plants by induction of oxidative stress. We have focused on the role of reactive oxygen species (ROS) and phytohormons (ABA and ethylene) in the biochemical and molecular regulation of plant response to sunflower phytotoxins.

Bogatek, Renata; Gniazdowska, Agnieszka

2007-01-01

106

Targeting extracellular ROS signaling of tumor cells.  

Science.gov (United States)

Expression of membrane-associated NADPH oxidase (NOX1) represents a characteristic feature of malignant cells. NOX1-derived extracellular superoxide anions are the basis for autocrine stimulation of proliferation, but also drive the HOCl and the NO/peroxynitrite signaling pathways. This may cause the elimination of transformed cells. Tumor cells express membrane-associated catalase that efficiently protects the cells against apoptosis-inducing reactive oxygen species (ROS) signaling. Membrane-associated superoxide dismutase (SOD) plays a co-modulatory protective role that is functionally interrelated with the protective effect mediated by catalase. Due to the co-localization of NOX1, catalase and SOD on the outer membrane of tumor cells, specific inhibition of membrane-associated SOD causes superoxide anion-dependent inhibition of catalase. This establishes a strong apoptotic signaling through the NO/peroxynitrite pathway. In parallel, it causes a drastic decrease in the concentration of proliferation-stimulating H2O2. Knowledge of the biochemical network on the surface of tumor cells should, therefore, allow development of specific novel strategies for tumor therapy, based on the specific features of tumor cell-specific extracellular ROS interactions. PMID:24692674

Bauer, Georg

2014-04-01

107

SUGV baseline autonomy using ROS  

Science.gov (United States)

Currently, the 3000+ robotic systems fielded in theater are entirely teleoperated. This constant dependence on operator control introduces several problems, including a large cognitive load on the operator and a limited ability for the operator to maintain an appropriate level of situational awareness of his surroundings. One solution to reduce the dependence on teleoperation is to develop autonomous behaviors for the robot to reduce the strain on the operator. We consider mapping and navigation to be fundamental to the development of useful field autonomy for small unmanned ground vehicles (SUGVs). To this end, we have developed baseline autonomous capabilities for our SUGV platforms, making use of the open-source Robot Operating System (ROS) software from Willow Garage, Inc. Their implementations of mapping and navigation are drawn from the most successful published academic algorithms in robotics. In this paper, we describe how we bridged our previous work with the Packbot Explorer to incorporate a new processing payload, new sensors, and the ROS system configured to perform the high-level autonomy tasks of mapping and waypoint navigation. We document our most successful parameter selection for the ROS navigation software in an indoor environment and present results of a mapping experiment.

Stump, Ethan; Sadler, Laurel; Baran, David

2011-05-01

108

ROS production and Glut1 activity in two human megakaryocytic cell lines.  

Science.gov (United States)

Reactive oxygen species (ROS) has been increasingly recognised as intracellular messengers in signal transduction following receptor activation by a variety of bioactive peptides including growth factors, cytokines and hormones. In this study ROS production and glucose transport activity were evaluated in the growth factor dependent M07e cells and in B1647 cells, not requiring additional hematopoietic cytokines for growth: the aim was to investigate whether ROS could be involved in the regulation of Glut1-mediated glucose uptake in both cell lines. The effect of the synthetic superoxide and hydrogen peroxide scavenger EUK-134 on DOG uptake activity and intracellular ROS formation supports the concept of reactive oxygen species as signalling molecules. In order to investigate ROS generation sources, diphenyleneiodonium, an inhibitor of flavoprotein centres and apocynin, an inhibitor of NAD(P)H oxidase, were used: they inhibit both ROS production and glucose uptake activation. All these data support the hypothesis that ROS can contribute to the regulation of glucose transport, not only in M07e cells but also in B1647 cells; we could speculate that one possible source of ROS, linked somehow with Glut1 activity, can be a NAD(P)H oxidase similar to that one present in phagocytic cells. PMID:15706059

Prata, Cecilia; Maraldi, Tullia; Zambonin, Laura; Fiorentini, Diana; Hakim, Gabriele; Landi, Laura

2004-01-01

109

A critical role for Romo1-derived ROS in cell proliferation  

International Nuclear Information System (INIS)

Low levels of endogenous reactive oxygen species (ROS) originating from NADPH oxidase have been implicated in various signaling pathways induced by growth factors and mediated by cytokines. However, the main source of ROS is known to be the mitochondria, and increased levels of ROS from the mitochondria have been observed in many cancer cells. Thus far, the mechanism of ROS production in cancer cell proliferation in the mitochondria is not well-understood. We recently identified a novel protein, ROS modulator 1 (Romo1), and reported that increased expression of Romo1-triggered ROS production in the mitochondria. The experiments conducted in the present study showed that Romo1-derived ROS were indispensable for the proliferation of both normal and cancer cells. Furthermore, whilst cell growth was inhibited by blocking the ERK pathway in cells transfected with siRNA directed against Romo1, the cell growth was recovered by addition of exogenous hydrogen peroxide. The results of this study suggest that Romo1-induced ROS may play an important role in redox signaling in cancer cells

2008-05-02

110

ROS-PIAS? cross talk channelizes ATM signaling from resistance to apoptosis during chemosensitization of resistant tumors  

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With the existing knowledge of ATM's role in therapeutic resistance, the present study aimed at identifying the molecular mechanisms that influence ATM to oscillate between chemoresistance and chemosensitivity. We observed that the redox status of tumors functions as a major determinant of ATM-dependent ‘resistance-to-apoptosis' molecular switch. At a low reactive oxygen species (ROS) condition during genotoxic insult, the ATM/sumoylated-IKK? interaction induced NF?B activation that resisted JNK-mediated apoptosis, whereas increasing cellular ROS restored ATM/JNK apoptotic signaling. A search for the upstream missing link revealed that high ROS induces oxidation and ubiquitin-mediated degradation of PIAS?, thereby disrupting PIAS?-IKK? cross talk, a pre-requisite for IKK? sumoylation and subsequent NF?B activation. Interruption in the PIAS?-mediated resistance pathway channels ATM signaling toward ATM/JNK pro-death circuitry. These in vitro results also translated to sensitive and resistant tumor allograft mouse models in which low ROS-induced resistance was over-ruled in PIAS? knockout tumors, while its overexpression inhibited high ROS-dependent apoptotic cues. Cumulatively, our findings identified an unappreciated yet critical combinatorial function of cellular ROS and PIAS? in regulating ATM-mediated chemosensitization of resistant tumors. Thus, therapeutic strategies employing ROS upregulation to inhibit PIAS? during genotoxic therapy may, in future, help to eliminate the problems of NF?B-mediated tumor drug resistance.

Mohanty, S; Saha, S; Md S Hossain, D; Adhikary, A; Mukherjee, S; Manna, A; Chakraborty, S; Mazumdar, M; Ray, P; Das, K; Chakraborty, J; Sa, G; Das, T

2014-01-01

111

The Oncogenic Lung Cancer Fusion Kinase CD74-ROS Activates a Novel Invasiveness Pathway Through E-Syt1 Phosphorylation  

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Patients with lung cancer often present with metastatic disease and therefore have a very poor prognosis. The recent discovery of several novel ROS receptor tyrosine kinase molecular alterations in non-small-cell lung cancer (NSCLC) presents a therapeutic opportunity for the development of new targeted treatment strategies. Here, we report that the NSCLC-derived fusion CD74-ROS, which accounts for 30% of all ROS fusion kinases in NSCLC, is an active and oncogenic tyrosine kinase. We found that CD74-ROS expressing cells were highly invasive in vitro and metastatic in vivo. Pharmacological inhibition of CD74-ROS kinase activity reversed its transforming capacity by attenuating downstrream signaling networks. Using quantitative phosphoproteomics, we uncovered a mechanism by which CD74-ROS activates a novel pathway driving cell invasion. Expression of CD74-ROS resulted in the phosphorylation of the extended synaptotagmin-like protein E-Syt1. Elimination of E-Syt1 expression drastically reduced invasiveness both in vitro and in vivo without modifying the oncogenic activity of CD74-ROS. Furthermore, expression of CD74-ROS in non-invasive NSCLC cell lines readily confered invasive properties that paralleled the acquisition of E-Syt1 phosphorylation. Taken together, our findings indicate that E-Syt1 is a mediator of cancer cell invasion and molecularly define ROS fusion kinases as therapeutic targets in the treatment of NSCLC.

Jun, Hyun Jung; Johnson, Hannah; Bronson, Roderick T.; de Feraudy, Sebastien; White, Forest; Charest, Alain

2013-01-01

112

3D perception with ROS and PCL  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Nowadays, first experiences in 3D perception can be easily obtained using ROS and PCL. ROS provides a communication layer and a user-friendly 3D visualization toolkit. PCL is an open source library containing various algorithms for point cloud processing.

Arbeiter, Georg

2013-01-01

113

Inhibition of cathepsin S induces autophagy and apoptosis in human glioblastoma cell lines through ROS-mediated PI3K/AKT/mTOR/p70S6K and JNK signaling pathways.  

Science.gov (United States)

Cathepsin S is a lysosomal cysteine protease that is overexpressed in various cancer models and plays important role in tumorigenesis, however the mechanisms are unclear. In the present study, we found that inhibition of cathepsin S induced autophagy and mitochondrial apoptosis in human glioblastoma cells. Blockade of autophagy by either a chemical inhibitor or RNA interference attenuated cathespin S inhibition-induced apoptosis. Furthermore, autophagy and apoptosis induction was dependent on the suppression of phosphatidylinositide 3-kinases/protein kinase B/mammalian target of rapamycin/p70S6 kinase (PI3K/AKT/mTOR/p70S6K) signaling pathway and activation of c-Jun N-terminal kinase (JNK) signaling pathway. In addition, reactive oxygen species (ROS) served as an upstream of PI3K/AKT/mTOR/p70S6K and JNK signaling pathways. In conclusion, the current study revealed that cathepsin S played an important role in the regulation of autophagy and apoptosis in human glioblastoma cells. PMID:24875536

Zhang, Li; Wang, Handong; Xu, Jianguo; Zhu, Jianhong; Ding, Ke

2014-08-01

114

ROS-GC interlocked Ca2+-sensor S100B protein signaling in cone photoreceptors: review  

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Photoreceptor rod outer segment membrane guanylate cyclase (ROS-GC) is central to visual transduction; it generates cyclic GMP, the second messenger of the photon signal. Photoexcited rhodopsin initiates a biochemical cascade that leads to a drop in the intracellular level of cyclic GMP and closure of cyclic nucleotide gated ion channels. Recovery of the photoresponse requires resynthesis of cyclic GMP, typically by a pair of ROS-GCs, 1 and 2. In rods, ROS-GCs exist as complexes with guanylate cyclase activating proteins (GCAPs), which are Ca2+-sensing elements. There is a light-induced fall in intracellular Ca2+. As Ca2+ dissociates from GCAPs in the 20–200 nM range, ROS-GC activity rises to quicken the photoresponse recovery. GCAPs then progressively turn down ROS-GC activity as Ca2+ and cyclic GMP levels return to baseline. To date, GCAPs mediate the only known mechanism of ROS-GC regulation in the photoreceptors. However, in mammalian cone outer segments, cone synapses and ON bipolar cells, another Ca2+ sensor protein, S100B, complexes with ROS-GC1 and senses the Ca2+ signal with a K1/2 of 400 nM. Unlike GCAPs, S100B stimulates ROS-GC activity when Ca2+ is bound. Thus, the ROS-GC system in cones functions as a Ca2+ bimodal switch; with rising intracellular Ca2+, its activity is first turned down by GCAPs and then turned up by S100B. This presentation provides a historical perspective on the role of S100B in the photoreceptors, offers a pictorial model for the “bimodal” operation of the ROS-GC switch and projects future tasks that are needed to understand its operation. Some accounts of this review have been adopted from the original publications of these authors.

Sharma, Rameshwar K.; Makino, Clint L.; Hicks, David; Duda, Teresa

2014-01-01

115

ROS-GC interlocked Ca2+-sensor S100B protein signaling in cone photoreceptors: Review  

Directory of Open Access Journals (Sweden)

Full Text Available Photoreceptor rod outer segment membrane guanylate cyclase (ROS-GC is central to visual transduction; it generates cyclic GMP, the second messenger of the photon signal. Photoexcited rhodopsin initiates a biochemical cascade that leads to a drop in the intracellular level of cyclic GMP and closure of cyclic nucleotide gated (CNG ion channels. Recovery of the photoresponse requires resynthesis of cyclic GMP, typically by a pair of ROS-GCs, 1 and 2. In rods, ROS-GCs exist as complexes with GCAPs, which are Ca2+-sensing elements. There is a light-induced fall in intracellular Ca2+. As Ca2+ dissociates from GCAPs in the 20 to 200 nM range, ROS-GC activity rises to quicken the photoresponse recovery. GCAPs then progressively turn down ROS-GC activity as Ca2+ and cyclic GMP levels return to baseline. To date, GCAPs mediate the only known mechanism of ROS-GC regulation in the photoreceptors. However, in mammalian cone outer segments, cone synapses and ON bipolar cells, another Ca2+ sensor protein, S100B, complexes with ROS-GC1 and senses the Ca2+ signal with a K1/2 of 400 nM. Unlike GCAPs, S100B stimulates ROS-GC activity when Ca2+ is bound. Thus, the ROS-GC system in cones functions as a Ca2+ bimodal switch; with rising intracellular Ca2+, its activity is first turned down by GCAPs and then turned up by S100B. This presentation provides a historical perspective on the role of S100B in the photoreceptors, offers a pictorial model for the “bimodal” operation of the ROS-GC switch and projects future tasks that are needed to understand its operation. Some accounts of this review have been adopted from the original publications of these authors.

RameshwarKSharma

2014-03-01

116

ROS1 immunohistochemistry for detection of ROS1-rearranged lung adenocarcinomas.  

Science.gov (United States)

ROS1 gene rearrangements are reported in 1% to 2% of lung adenocarcinomas (ACAs) and are associated with response to the multitargeted tyrosine kinase inhibitor crizotinib. ROS1 rearrangements can be detected using fluorescence in situ hybridization (FISH); however, immunohistochemistry (IHC) for ROS1 protein is a promising alternate screening modality. In this study, we examine the correlation between ROS1 IHC and FISH and describe the clinicopathologic characteristics of ROS1-rearranged lung tumors. ROS1 IHC was performed using clone D4D6 on whole-tissue sections. In a validation cohort, IHC was compared with ROS1 break-apart FISH in 53 cases of lung ACA enriched for an absence of known genetic alterations and never-smoking status. In a screening cohort, we performed ROS1 IHC on 167 consecutive cases of lung ACA from a routine molecular diagnostic practice and confirmed positive results by FISH. In the validation cohort, 6 cases (11%) were both FISH and IHC positive. One FISH-negative case was strongly ROS1 IHC positive. All IHC-negative cases were FISH negative. In the screening cohort, 2 of 167 (1.2%) had strong, diffuse ROS1 protein expression; a rearrangement was confirmed by FISH in both. ROS1-translocated tumors were wild type for EGFR, KRAS, and ALK and commonly had solid growth with mucinous/cribriform features and psammomatous calcification. ROS1 protein expression in tumor cells is 100% sensitive and 92% specific for ROS1 rearrangements by FISH. ROS1 IHC is an effective screening tool for this rare but clinically important subset of lung ACAs. PMID:23887156

Sholl, Lynette M; Sun, Heather; Butaney, Mohit; Zhang, Chengsheng; Lee, Charles; Jänne, Pasi A; Rodig, Scott J

2013-09-01

117

Overview on how oncogenic Kras promotes pancreatic carcinogenesis by inducing low intracellular ROS levels  

Directory of Open Access Journals (Sweden)

Full Text Available Pancreatic ductal adenocarcinoma (PDAC is a devastating disease without clearly known disease causes. Recent epidemiological and animal studies suggest that the supplementation of dietary antioxidants (e.g. vitamins C and E decreases cancer risk, implying that increased reactive oxygen species (ROS may play a role in pancreatic carcinogenesis. However, oncogenic Kras mutations (e.g. KrasG12D, which are present in more than 90% of PDAC, have been proven to foster low intracellular ROS levels. Here, oncogenic Kras activates expression of a series of anti-oxidant genes via Nrf2 (nuclear factor, erythroid derived 2, like 2 and also mediates an unusual metabolic pathway of glutamine to generate NADPH. This can then be used as the reducing power for ROS detoxification, leading collectively to low ROS levels in pancreatic pre-neoplastic cells and in cancer cells. In adult stem cells and cancer stem cells, low ROS levels have been associated with the formation of a proliferation-permissive intracellular environment and with perseverance of self-renewal capacities. Therefore, it is conceivable that low intracellular ROS levels may contribute significantly to oncogenic Kras-mediated PDAC formation.

ChristophWMichalski

2013-09-01

118

Research Outcomes System (ROS) - Research Councils UK  

ROS was developed in consultation with researchers, Research ... and used in \\various reports and case studies to demonstrate the value of the research they \\fund. ... previous methods – just two minutes to submit details of a journal or book\\.

119

Mitochondrial complex III ROS regulate adipocyte differentiation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Adipocyte differentiation is characterized by an increase in mitochondrial metabolism. However it is not known whether the increase in mitochondrial metabolism is essential for differentiation or a byproduct of the differentiation process. Here, we report that primary human mesenchymal stem cells undergoing differentiation into adipocytes display an early increase in mitochondrial metabolism, biogenesis, and ROS generation. This early increase in mitochondrial metabolism and ROS generation wa...

Tormos, Kathryn V.; Anso, Elena; Hamanaka, Robert B.; Eisenbart, James; Joseph, Joy; Kalyanaraman, Balaraman; Chandel, Navdeep S.

2011-01-01

120

Biophysical properties and functional consequences of reactive oxygen species (ROS)-induced ROS release in intact myocardium.  

Science.gov (United States)

Reactive oxygen species (ROS)-induced ROS release (RIRR) is a fundamental mechanism by which cardiac mitochondria respond to elevated ROS levels by stimulating endogenous ROS production in a regenerative, autocatalytic process that ultimately results in global oxidative stress (OS), cellular dysfunction and death. Despite elegant studies describing the phenomenon of RIRR under artificial conditions such as photo-induced oxidation of discrete regions within cardiomyocytes, the existence, biophysical properties and functional consequences of RIRR in intact myocardium remain unclear. Here, we used a semi-quantitative approach of optical superoxide (O(2)(-)) mapping using dihydroethidium (DHE) fluorescence to explore RIRR, its arrhythmic consequences and underlying mechanisms in intact myocardium. Initially, perfusion of rat hearts with 200 ?M H(2)O(2) for 40 min (n = 4) elicited two distinct O(2)(-) peaks that were readily distinguished by their timing and amplitude. The first peak (P1), which was generated rapidly (within 5-8 min of H(2)O(2) perfusion) was associated with a relatively limited (10 ± 2%) rise in normalized O(2)(-) levels relative to baseline. In contrast, the second peak (P2) occurred 19-26 min following onset of H(2)O(2) perfusion and was associated with a significantly greater amplitude compared to P1. Spatio-temporal ROS mapping during P2 revealed active O(2)(-) propagation across the myocardium at a velocity of ~20 ?m s(-1). Exposure of hearts (n = 18) to a short (10 min) episode of H(2)O(2) perfusion revealed consistent generation of P2 by high (?200 ?M, 8/8) but not lower (?100 ?M, 3/8) H(2)O(2) concentrations (P EUK-134 completely abolished the H(2)O(2)-mediated RIRR response as well as the incidence of arrhythmias. These findings extend the concept of RIRR to the level of the intact heart, establish regenerative O(2)(-) production as the mediator of RIRR-related arrhythmias and reveal their strong dependence on IMAC and not the mPTP in this acute model of OS. PMID:21825030

Biary, Nora; Xie, Chaoqin; Kauffman, Justin; Akar, Fadi G

2011-11-01

 
 
 
 
121

Mitochondrial reactive oxygen species (ROS) as signaling molecules of intracellular pathways triggered by the cardiac renin-angiotensin II-aldosterone system (RAAS)  

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Mitochondria represent major sources of basal reactive oxygen species (ROS) production of the cardiomyocyte. The role of ROS as signaling molecules that mediate different intracellular pathways has gained increasing interest among physiologists in the last years. In our lab, we have been studying the participation of mitochondrial ROS in the intracellular pathways triggered by the renin-angiotensin II-aldosterone system (RAAS) in the myocardium during the past few years. We have demonstrated ...

Giusti, V. C.; Caldiz, C. I.; Ennis, I. E.; Pe?rez, N. G.; Cingolani, H. E.; Aiello, E. A.

2013-01-01

122

Downregulation of ROS-FIG inhibits cell proliferation, colony?formation, cell cycle progression, migration and invasion, while inducing apoptosis in intrahepatic cholangiocarcinoma cells.  

Science.gov (United States)

Intrahepatic cholangiocarcinoma (ICC) is the second most common primary liver cancer with poor responsiveness to existing drug therapies. Therefore, novel treatment strategies against ICC are required to improve survival. The aim of this study was to demonstrate the role of fused-in-glioblastoma-c-ros-oncogene1 (FIG-ROS) fusion gene in ICC. ROS was positively expressed in ICC tissues and HUCCT1 cells. Plasmids expressing ROS- and FIG-specific shRNAs were constructed and transfected into HUCCT1 cells. The results showed that single transfection of ROS- or FIG-specific shRNA inhibited HUCCT1 cell proliferation, colony formation, cell cycle progression, migration and invasion, while inducing apoptosis. Moreover, the co-inhibition of ROS- and FIG-specific shRNA exhibited stronger effects on HUCCT1 cell proliferation, apoptosis, colony formation, cell cycle progression, migration and invasion, when compared to single inhibition of ROS and FIG. Furthermore, findings of this study suggested that the AKT signaling pathway was involved in the ROS-FIG-mediated biological processes of HUCCT1 cells. In summary, the results suggest that FIG-ROS plays an oncogenic role in ICC. Additionally, ROS1-6290 and FIG-363 segments may become effective therapeutic targets for ICC harboring ROS-FIG fusion protein. PMID:24968753

Deng, Gang; Hu, Chenghuan; Zhu, Lei; Huang, Feizhou; Huang, Wei; Xu, Hongbo; Nie, Wanpin

2014-09-01

123

Targeting CSCs in tumor microenvironment: the potential role of ROS-associated miRNAs in tumor aggressiveness.  

Science.gov (United States)

Reactive oxygen species (ROS) have been widely considered as critical cellular signaling molecules involving in various biological processes such as cell growth, differentiation, proliferation, apoptosis, and angiogenesis. The homeostasis of ROS is critical to maintain normal biological processes. Increased production of ROS, namely oxidative stress, due to either endogenous or exogenous sources causes irreversible damage of bio-molecules such as DNA, proteins, lipids, and sugars, leading to genomic instability, genetic mutation, and altered gene expression, eventually contributing to tumorigenesis. A great amount of experimental studies in vitro and in vivo have produced solid evidence supporting that oxidative stress is strongly associated with increased tumor cell growth, treatment resistance, and metastasis, and all of which contribute to tumor aggressiveness. More recently, the data have indicated that altered production of ROS is also associated with cancer stem cells (CSCs), epithelial-to-mesenchymal transition (EMT), and hypoxia, the most common features or phenomena in tumorigenesis and tumor progression. However, the exact mechanism by which ROS is involved in the regulation of CSC and EMT characteristics as well as hypoxia- and, especially, HIF-mediated pathways is not well known. Emerging evidence suggests the role of miRNAs in tumorigenesis and progression of human tumors. Recently, the data have indicated that altered productions of ROS are associated with deregulated expression of miRNAs, suggesting their potential roles in the regulation of ROS production. Therefore, targeting ROS mediated through the deregulation of miRNAs by novel approaches or by naturally occurring anti-oxidant agents such as genistein could provide a new therapeutic approach for the prevention and/or treatment of human malignancies. In this article, we will discuss the potential role of miRNAs in the regulation of ROS production during tumorigenesis. Finally, we will discuss the role of genistein, as a potent anti-tumor agent in the regulation of ROS production during tumorigenesis and tumor development. PMID:23957937

Bao, Bin; Azmi, Asfar S; Li, Yiwei; Ahmad, Aamir; Ali, Shadan; Banerjee, Sanjeev; Kong, Dejuan; Sarkar, Fazlul H

2014-01-01

124

ROS sets the stage for macrophage differentiation.  

Science.gov (United States)

While M1 macrophages are highly pro-inflammatory and microbicidal, M2 macrophages and the related tumor associated macrophages (TAMs) regulate tissue remodeling and angiogenesis and can display immunomodulatory activity. In July issue of Cell Research, Zhang et al. show that ROS production, critical for the activation and functions of M1 macrophages, is necessary for the differentiation of M2 macrophages and TAMs, and that antioxidant therapy blocks TAM differentiation and tumorigenesis in mouse models of cancer. PMID:23835480

Covarrubias, Anthony; Byles, Vanessa; Horng, Tiffany

2013-08-01

125

Pro-metastatic signaling by c-Met through RAC-1 and reactive oxygen species (ROS).  

Science.gov (United States)

Overexpression of the c-Met/hepatocyte growth factor receptor(HGF-R) proto-oncogene and abnormal generation of intracellular oxygen species (reactive oxygen species (ROS)) have been linked, by independent lines of evidence, to cell transformation and to malignant growth. By comparing two subpopulations of the B16 mouse melanoma (B16-F0 and B16-F10) endowed with different lung metastasis capacities (low and high, respectively) we found that both the expression/phosphorylation of c-Met and the steady-state levels of ROS positively correlated with metastatic growth. shRNA-mediated downregulation of c-Met in F10 cells led to a parallel decrease in the generation of oxygen species and in metastatic capacity, suggesting that oxidants may mediate the pro-metastatic activity of the HGF receptor. c-Met activation by a ligand elicits the formation of oxidant species through the oxidase-coupled small GTPase Rac-1, a relevant downstream target of the HGF-R. Moreover, cell treatment with the catalytic ROS scavengers EUK-134 and EUK-189 attenuates Met signaling to ERKs and inhibits the anchorage-independent growth of F10 cells, consistent with a critical role for oxygen species in HGF signaling and in aggressive cell behavior. Finally, genetic manipulation of the Rac-ROS cascade at different levels demonstrated its crucial role in the pro-metastatic activity of c-Met in vivo. Thus, we have outlined a novel cascade triggered by c-Met and mediated by ROS, linked to metastasis and potentially targetable by new antimetastatic, redox-based therapies. PMID:16462764

Ferraro, D; Corso, S; Fasano, E; Panieri, E; Santangelo, R; Borrello, S; Giordano, S; Pani, G; Galeotti, T

2006-06-22

126

Sirt3, Mitochondrial ROS, Ageing, and Carcinogenesis  

Directory of Open Access Journals (Sweden)

Full Text Available One fundamental observation in cancer etiology is that the rate of malignancies in any mammalian population increases exponentially as a function of age, suggesting a mechanistic link between the cellular processes governing longevity and carcinogenesis. In addition, it is well established that aberrations in mitochondrial metabolism, as measured by increased reactive oxygen species (ROS, are observed in both aging and cancer. In this regard, genes that impact upon longevity have recently been characterized in S. cerevisiae and C. elegans, and the human homologs include the Sirtuin family of protein deacetylases. Interestingly, three of the seven sirtuin proteins are localized into the mitochondria suggesting a connection between the mitochondrial sirtuins, the free radical theory of aging, and carcinogenesis. Based on these results it has been hypothesized that Sirt3 functions as a mitochondrial fidelity protein whose function governs both aging and carcinogenesis by modulating ROS metabolism. Sirt3 has also now been identified as a genomically expressed, mitochondrial localized tumor suppressor and this review will outline potential relationships between mitochondrial ROS/superoxide levels, aging, and cell phenotypes permissive for estrogen and progesterone receptor positive breast carcinogenesis.

David Gius

2011-09-01

127

Glucose initially inhibits and later stimulates blood ROS generation  

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Background: Glucose is the main substrate for the generation of NADPH, the cofactor of the oxidative burst enzyme NADPH-oxidase of blood neutrophils. Changes in blood glucose are thus expected to modify the generation of reactive oxygen species (ROS). The new blood ROS generation assay (BRGA) quantifies ROS changes induced by blood glucose concentrations as they are found in d...

Thomas Stief

2013-01-01

128

Comparison of UVA-induced ROS and sunscreen nanoparticle-generated ROS in human immune cells.  

Science.gov (United States)

Oxidative damage to cells and tissues from free radicals induced by ultraviolet (UV) irradiation can be attenuated by sunscreen components, such as ZnO and TiO2 nanoparticles (NPs). Although it is known that reactive oxygen species (ROS) are generated by cells upon exposure to ZnO and TiO2 NPs, it is unknown to what extent the amount generated is altered with UV co-exposure. As it is a critical component for determining the relative risk of these NPs when used in sunscreen formulations, we have investigated ROS generation by these NPs in human THP-1 monocyte immune cells following UVA co-exposure. Whilst the applied UVA dose (6.7 J cm(-2)) did not alter cell viability after 24 h, it induced significant ROS production - causing a 7-fold increase in intracellular peroxide and 3.3-fold increase in mitochondrial superoxide levels after 1 h. However, co-exposure to NPs and UVA generated the same or less ROS than with UVA exposure alone, with the exception of anatase TiO2, which showed significantly increased levels. These findings indicate that ROS generation from nanosunscreens is, in most cases, an insignificant contributor to the overall risk associated with oxidative stress from UVA exposure itself. PMID:24664431

Shen, Cenchao; Turney, Terence W; Piva, Terrence J; Feltis, Bryce N; Wright, Paul F A

2014-05-01

129

Oncogene-induced Nrf2 transcription promotes ROS detoxification and tumorigenesis  

Science.gov (United States)

Reactive oxygen species (ROS) are mutagenic and may thereby promote cancer1. Normally, ROS levels are tightly controlled by an inducible antioxidant program that responds to cellular stressors and is predominantly regulated by the transcription factor Nrf2 and its repressor protein Keap12-5. In contrast to the acute physiological regulation of Nrf2, in neoplasia there is evidence for increased basal activation of Nrf2. Indeed, somatic mutations that disrupt the Nrf2-Keap1 interaction to stabilize Nrf2 and increase the constitutive transcription of Nrf2 target genes were recently identified, suggesting that enhanced ROS detoxification and additional Nrf2 functions may in fact be pro-tumorigenic6. Here, we investigated ROS metabolism in primary murine cells following the expression of endogenous oncogenic alleles of K-Ras, B-Raf and Myc, and find that ROS are actively suppressed by these oncogenes. K-RasG12D, B-RafV619E and MycERT2 each increased the transcription of Nrf2 to stably elevate the basal Nrf2 antioxidant program and thereby lower intracellular ROS and confer a more reduced intracellular environment. Oncogene-directed increased expression of Nrf2 is a novel mechanism for the activation of the Nrf2 antioxidant program, and is evident in primary cells and tissues of mice expressing K-RasG12D and B-RafV619E, and in human pancreatic cancer. Furthermore, genetic targeting of the Nrf2 pathway impairs K-RasG12D-induced proliferation and tumorigenesis in vivo. Thus, the Nrf2 antioxidant and cellular detoxification program represents a previously unappreciated mediator of oncogenesis.

DeNicola, Gina M.; Karreth, Florian A.; Humpton, Timothy J.; Gopinathan, Aarthi; Wei, Cong; Frese, Kristopher; Mangal, Dipti; Yu, Kenneth H.; Yeo, Charles J.; Calhoun, Eric S.; Scrimieri, Francesca; Winter, Jordan M.; Hruban, Ralph H.; Iacobuzio-Donahue, Christine; Kern, Scott E.; Blair, Ian A.; Tuveson, David A.

2012-01-01

130

TRPs as Chemosensors (ROS, RNS, RCS, Gasotransmitters).  

Science.gov (United States)

The transient receptor potential (trp) gene superfamily encodes TRP proteins that act as multimodal sensor cation channels for a wide variety of stimuli from outside and inside the cell. Upon chemical or physical stimulation of cells, TRP channels transduce electrical and/or Ca(2+) signals via their cation channel activities. These functional features of TRP channels allow the body to react and adapt to different forms of environmental changes. Indeed, members of one class of TRP channels have emerged as sensors of reactive oxygen species (ROS), reactive nitrogen species (RNS), reactive carbonyl species (RCS), and gaseous messenger molecules including molecular oxygen (O2), hydrogen sulfide (H2S), and carbon dioxide (CO2). Hydrogen peroxide (H2O2), an ROS, triggers the production of ADP-ribose, which binds and activates TRPM2. In addition to TRPM2, TRPC5, TRPV1, and TRPA1 are also activated by H2O2 via modification of cysteine (Cys) free sulfhydryl groups. Nitric oxide (NO), a vasoactive gaseous molecule, regulates TRP channels directly via Cys S-nitrosylation or indirectly via cyclic GMP (cGMP)/protein kinase G (PKG)-dependent phosphorylation. Anoxia induced by O2-glucose deprivation and severe hypoxia activates TRPM7 and TRPC6, respectively, whereas TRPA1 serves as a sensor of mild hypoxia and hyperoxia in vagal and sensory neurons. TRPA1 also detects other gaseous molecules, such as hydrogen sulfide (H2S) and carbon dioxide (CO2). In this review, we highlight our current knowledge of TRP channels as chemosensors for ROS, RNS, RCS, and gaseous molecules and discuss their functional impacts on physiological and pathological events. PMID:24961969

Shimizu, Shunichi; Takahashi, Nobuaki; Mori, Yasuo

2014-01-01

131

PFT1-controlled ROS balance is critical for multiple stages of root hair development in Arabidopsis.  

Science.gov (United States)

Reactive oxygen species (ROS) have been shown to play key roles in cellular decision making and signal integration in multicellular organisms. In roots, ROS levels are managed by the action of peroxidases and NAPDH oxidases, resulting in a distinct spatial distribution of hydrogen peroxide (H?O?) and superoxide (O?(-)) that is critical for the balance between cell proliferation and differentiation. In addition, ROS is required for the determination of the cell shape of root hairs. Mutations in the Mediator subunit MED25/PFT1 result in compromised root hair development, due to altered expression of a suite of H?O?-producing class III peroxidases. pft1-1 mutants form shorter root hairs than wild-type plants. Analysis of pft1-1 cross-sections revealed that also root hair initiation is compromised, probably by impeding local cell wall loosening. It is suggested that ROS homeostasis is critical throughout the development of root hairs, controlling various processes via PFT1-regulated transcription of genes encoding redox-active enzymes. PMID:23455023

Sundaravelpandian, Kalaipandian; Chandrika, Nulu; Tsai, Yi-Hsiu; Schmidt, Wolfgang

2013-05-01

132

PARP-1 Hyperactivation and Reciprocal Elevations in Intracellular Ca2+ During ROS-Induced Nonapoptotic Cell Death.  

Science.gov (United States)

The generation of reactive oxygen species (ROS) has been implicated in the pathogenesis of renal ischemia/reperfusion injury, and many other pathological conditions. DNA strand breaks caused by ROS lead to the activation of poly(ADP-ribose)polymerase-1 (PARP-1), the excessive activation of which can result in cell death. We have utilized a model in which 2,3,5-tris(glutathion-S-yl)hydroquinone (TGHQ), a nephrotoxic and nephrocarcinogenic metabolite of hydroquinone, causes ROS-dependent cell death in human renal proximal tubule epithelial cells (HK-2), to further elucidate the role of PARP-1 in ROS-dependent cell death. TGHQ-induced ROS generation, DNA strand breaks, hyperactivation of PARP-1, rapid depletion of nicotinamide adenine dinucleotide (NAD), elevations in intracellular Ca(2+) concentrations, and subsequent nonapoptotic cell death in both a PARP- and Ca(2+)-dependent manner. Thus, inhibition of PARP-1 with PJ34 completely blocked TGHQ-mediated accumulation of poly(ADP-ribose) polymers and NAD consumption, and delayed HK-2 cell death. In contrast, chelation of intracellular Ca(2+) with BAPTA completely abrogated TGHQ-induced cell death. Ca(2+) chelation also attenuated PARP-1 hyperactivation. Conversely, inhibition of PARP-1 modulated TGHQ-mediated changes in Ca(2+) homeostasis. Interestingly, PARP-1 hyperactivation was not accompanied by the translocation of apoptosis-inducing factor (AIF) from mitochondria to the nucleus, a process usually associated with PARP-dependent cell death. Thus, pathways coupling PARP-1 hyperactivation to cell death are likely to be context-dependent, and therapeutic strategies designed to target PARP-1 need to recognize such variability. Our studies provide new insights into PARP-1-mediated nonapoptotic cell death, during which PARP-1 hyperactivation and elevations in intracellular Ca(2+) are reciprocally coupled to amplify ROS-induced nonapoptotic cell death. PMID:24752504

Zhang, Fengjiao; Xie, Ruiye; Munoz, Frances M; Lau, Serrine S; Monks, Terrence J

2014-07-01

133

Formononetin potentiates epirubicin-induced apoptosis via ROS production in HeLa cells in vitro.  

Science.gov (United States)

The frequent development of multidrug resistance (MDR) hampers the efficacy of available anticancer drugs in treating cervical cancer. In this study, we aimed to use formononetin (7-hydroxy-4'-methoxyisoflavone), a potential herbal isoflavone, to intensify the chemosensitivity of human cervical cancer HeLa cells to epirubicin, an anticancer drug. The reactive oxygen species (ROS) levels were correlated with MDR modulation mechanisms, including the transporter inhibition and apoptosis induction. Our results revealed that formononetin significantly enhanced the cytotoxicity of epirubicin. Co-incubation of epirubicin with formononetin increased the ROS levels, including hydrogen peroxide and superoxide free radicals. Epirubicin alone markedly increased the mRNA expression of MDR1, MDR-associated protein (MRP) 1, and MRP2. In contrast, formononetin alone or combined treatment decreased the mRNA expression of MRP1 and MRP2. This result indicates that efflux transporter-mediated epirubicin resistance is inhibited at different degrees by the addition of formononetin. This isoflavone significantly intensified epirubicin uptake into HeLa cells. Apoptosis was induced by formononetin and/or epirubicin, as signified by nuclear DNA fragmentation, chromatin condensation, increased sub-G1 and G2/M phases. The cotreatment triggered the mitochondrial apoptotic pathway indicated by increased Bax-to-Bcl-2 expression ratio, loss of mitochondrial membrane potential, and significant activation of caspase-9 and -3. In addition, extrinsic/caspases-8 apoptotic pathway was also induced by the cotreatment. N-acetyl cysteine abrogated these events induced by formononetin, supporting the involvement of ROS in the MDR reversal mechanism. This study pioneered in demonstrating that formononetin may potentiate the cytotoxicity of epirubicin in HeLa cells through the ROS-mediated MRP inhibition and concurrent activation of the mitochondrial and death receptor pathways of apoptosis. Hence, the circumvention of pump and non-pump resistance using formononetin and epirubicin may pave the way for a powerful chemotherapeutic regimen for treating human cervical cancer. PMID:23867903

Lo, Yu-Li; Wang, Wanjen

2013-10-01

134

ROS-dependent anticandidal activity of zinc oxide nanoparticles synthesized by using egg albumen as a biotemplate  

International Nuclear Information System (INIS)

Zinc oxide nanoparticles (ZnO NPs) have attracted great attention because of their superior optical properties and wide application in biomedical science. However, little is known about the anticandidal activity of ZnO NPs against Candida albicans (C. albicans). This study was designed to develop the green approach to synthesize ZnO NPs using egg white (denoted as EtZnO NPs) and investigated its possible mechanism of antimicrobial activity against C. albicans 077. It was also notable that anticandidal activity of EtZnO NPs is correlated with reactive oxygen species (ROS) production in a dose dependent manner. Protection of histidine against ROS clearly suggests the implication of ROS in anticandidal activity of EtZnO NPs. This green approach based on egg white-mediated synthesis of ZnO NPs paves the way for developing cost effective, eco-friendly and promising antimicrobial nanomaterial for applications in medicine. (paper)

2013-09-01

135

FTY720 stimulated ROS generation and the Sty1/Atf1 signaling pathway in the fission yeast Schizosaccharomyces pombe.  

Science.gov (United States)

Fingolimod hydrochloride (FTY720) is the first-in-class immune modulator known as sphingosine 1-phosphate (S1P) receptor agonists. FTY720 has also been reported to exert a variety of physiological functions such as antitumor effect, angiogenesis inhibition, and Ca2+ mobilization. Here, we show that FTY720 treatment induced reactive oxygen species (ROS) accumulation, and investigated the effect of FTY720 on the stress-activated MAP kinase Spc1/Sty1, a functional homologue of p38 MAPK, using a Renilla luciferase reporter construct fused to the CRE, which gives an accurate measure of the transcriptional activity of Atf1 and thus serves as a faithful readout of the Spc1/Sty1 MAPK signaling in response to oxidative stresses. FTY720 stimulated the CRE responses in a concentration-dependent manner, which was markedly reduced by deletion of the components of the Spc1/Sty1 MAPK pathway. The blockade of ROS production by NAC (N-acetyl-L-cysteine) significantly reversed the FTY720-induced ROS accumulation, subsequent activation of the Spc1/Sty1 MAPK pathway, and inhibition of cell proliferation. Cells lacking the components of the Spc1/Sty1 MAPK exhibited higher sensitivity to FTY720 and higher ROS levels upon FTY720 treatment than in wild-type cells. Thus, our results demonstrate the usefulness of fission yeast for elucidating the FTY720-mediated signaling pathways involving ROS. PMID:24506481

Hagihara, Kanako; Mizukura, Aya; Kitai, Yuki; Yao, Mariko; Ishida, Kouki; Kita, Ayako; Kunoh, Tatsuki; Masuko, Takashi; Matzno, Sumio; Chiba, Kenji; Sugiura, Reiko

2014-04-01

136

MaROS: Information Management Service  

Science.gov (United States)

This software is provided by the Mars Relay Operations Service (MaROS) task to a variety of Mars projects for the purpose of coordinating communications sessions between landed spacecraft assets and orbiting spacecraft assets at Mars. The Information Management Service centralizes a set of functions previously distributed across multiple spacecraft operations teams, and as such, greatly improves visibility into the end-to-end strategic coordination process. Most of the process revolves around the scheduling of communications sessions between the spacecraft during periods of time when a landed asset on Mars is geometrically visible by an orbiting spacecraft. These relay sessions are used to transfer data both to and from the landed asset via the orbiting asset on behalf of Earth-based spacecraft operators. This software component is an application process running as a Java virtual machine. The component provides all service interfaces via a Representational State Transfer (REST) protocol over https to external clients. There are two general interaction modes with the service: upload and download of data. For data upload, the service must execute logic specific to the upload data type and trigger any applicable calculations including pass delivery latencies and overflight conflicts. For data download, the software must retrieve and correlate requested information and deliver to the requesting client. The provision of this service enables several key advancements over legacy processes and systems. For one, this service represents the first time that end-to-end relay information is correlated into a single shared repository. The software also provides the first multimission latency calculator; previous latency calculations had been performed on a mission-by-mission basis.

Allard, Daniel A.; Gladden, Roy E.; Wright, Jesse J.; Hy, Franklin H.; Rabideau, Gregg R.; Wallick, Michael N.

2011-01-01

137

Ceramide-induced formation of ROS and ATP depletion trigger necrosis in lymphoid cells.  

Science.gov (United States)

In lymphocytes, Fas activation leads to both apoptosis and necrosis, whereby the latter form of cell death is linked to delayed production of endogenous ceramide and is mimicked by exogenous administration of long- and short-chain ceramides. Here molecular events associated with noncanonical necrotic cell death downstream of ceramide were investigated in A20 B lymphoma and Jurkat T cells. Cell-permeable, C6-ceramide (C6), but not dihydro-C6-ceramide (DH-C6), induced necrosis in a time- and dose-dependent fashion. Rapid formation of reactive oxygen species (ROS) within 30 min of C6 addition detected by a dihydrorhodamine fluorescence assay, as well as by electron spin resonance, was accompanied by loss of mitochondrial membrane potential. The presence of N-acetylcysteine or ROS scavengers like Tiron, but not Trolox, attenuated ceramide-induced necrosis. Alternatively, adenovirus-mediated expression of catalase in A20 cells also attenuated cell necrosis but not apoptosis. Necrotic cell death observed following C6 exposure was associated with a pronounced decrease in ATP levels and Tiron significantly delayed ATP depletion in both A20 and Jurkat cells. Thus, apoptotic and necrotic death induced by ceramide in lymphocytes occurs via distinct mechanisms. Furthermore, ceramide-induced necrotic cell death is linked here to loss of mitochondrial membrane potential, production of ROS, and intracellular ATP depletion. PMID:18191646

Villena, Joan; Henriquez, Mauricio; Torres, Vicente; Moraga, Francisco; Díaz-Elizondo, Jessica; Arredondo, Cristian; Chiong, Mario; Olea-Azar, Claudio; Stutzin, Andres; Lavandero, Sergio; Quest, Andrew F G

2008-03-15

138

ROS signaling, oxidative stress and Nrf2 in pancreatic beta-cell function  

International Nuclear Information System (INIS)

This review focuses on the emerging evidence that reactive oxygen species (ROS) derived from glucose metabolism, such as H2O2, act as metabolic signaling molecules for glucose-stimulated insulin secretion (GSIS) in pancreatic beta-cells. Particular emphasis is placed on the potential inhibitory role of endogenous antioxidants, which rise in response to oxidative stress, in glucose-triggered ROS and GSIS. We propose that cellular adaptive response to oxidative stress challenge, such as nuclear factor E2-related factor 2 (Nrf2)-mediated antioxidant induction, plays paradoxical roles in pancreatic beta-cell function. On the one hand, induction of antioxidant enzymes protects beta-cells from oxidative damage and possible cell death, thus minimizing oxidative damage-related impairment of insulin secretion. On the other hand, the induction of antioxidant enzymes by Nrf2 activation blunts glucose-triggered ROS signaling, thus resulting in reduced GSIS. These two premises are potentially relevant to impairment of beta-cells occurring in the late and early stage of Type 2 diabetes, respectively. In addition, we summarized our recent findings that persistent oxidative stress due to absence of uncoupling protein 2 activates cellular adaptive response which is associated with impaired pancreatic beta-cell function.

2010-04-01

139

Autophagy pathways activated in response to PDT contribute to cell resistance against ROS damage.  

Science.gov (United States)

Reactive oxygen species (ROS) concurrently instigate apoptosis and autophagy pathways, but the link between these processes remains unclear. Because cytotoxic ROS formation is exploited in anticancer therapy, such as in photodynamic therapy (PDT), a better understanding of the complex interplay between autophagy and apoptosis is urgently required. Previously, we reported that ROS generated by PDT with an endoplasmic reticulum (ER)-associated sensitizer leads to loss of ER-Ca(2+) homeostasis, ER stress and apoptosis. Here we show that PDT prompted Akt-mTOR (mammalian target of rapamycin) pathway down-regulation and stimulated macroautophagy (MA) in cancer and normal cells. Overexpression of the antioxidant enzyme glutathione peroxidase-4 reversed mTOR down-regulation and blocked MA progression and apoptosis. Attenuating MA using Atg5 knockdown or 3-methyladenine, reduced clearance of oxidatively damaged proteins and increased apoptosis, thus revealing a cytoprotective role of MA in PDT. Paradoxically, genetic loss of MA improved clearance of oxidized proteins and reduced photokilling. We found that up-regulation of chaperone-mediated autophagy (CMA) in unstressed Atg(-/-) cells compensated for MA loss and increased cellular resistance to PDT. CMA-deficient cells were significantly sensitized to photokilling but were protected against the ER stressor thapsigargin. These results disclose a stress-specific recruitment of autophagy pathways with cytoprotective function and unravel CMA as the dominant defence mechanism against PDT. PMID:20626525

Dewaele, Michael; Martinet, Wim; Rubio, Noemí; Verfaillie, Tom; de Witte, Peter A; Piette, Jacques; Agostinis, Patrizia

2011-06-01

140

Philip Glass, Scott Walker ja Sigur Ros! / Immo Mihkelson  

Index Scriptorium Estoniae

Pimedate Ööde 11. filmifestivali muusikafilme - Austraalia "Glass: Philipi portree 12 osas" (rež. Scott Hicks), Islandi "Sigur Ros kodus" (rež. Dean DeBois), Suurbritannia "Scott Walker: 30 Century Man" (rež. Stephen Kijak)

Mihkelson, Immo, 1959-

2007-01-01

 
 
 
 
141

NO, ROS, and cell death associated with caspase-like activity increase in stress-induced microspore embryogenesis of barley  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Under specific stress treatments (cold, starvation), in vitro microspores can be induced to deviate from their gametophytic development and switch to embryogenesis, forming haploid embryos and homozygous breeding lines in a short period of time. The inductive stress produces reactive oxygen species (ROS) and nitric oxide (NO), signalling molecules mediating cellular responses, and cell death, modifying the embryogenic microspore response and therefore, the efficiency of the process. This work...

Rodri?guez-serrano, Mari?a; Ba?ra?ny, Ivett; Prem, Deepak; Coronado, Mari?a-jose?; Risuen?o, Mari?a C.; Testillano, Pilar S.

2012-01-01

142

Mechanistic Investigation of ROS-Induced DNA Damage by Oestrogenic Compounds in Lymphocytes and Sperm Using the Comet Assay  

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Past research has demonstrated that oestrogenic compounds produce strand breaks in the DNA of sperm and lymphocytes via reactive oxygen species (ROS). In the current investigation, sperm and lymphocytes were treated in vitro with oestrogenic compounds (diethylstilboestrol, progesterone, 17?-oestradiol, noradrenaline and triiodotyronine) and several aspects of DNA damage were investigated. Firstly, mediation of DNA damage by lipid peroxidation was investigated in the presence of BHA (a lipid ...

Eduardo Cemeli; Diana Anderson

2011-01-01

143

Redox-optimized ROS balance: a unifying hypothesis.  

Science.gov (United States)

While it is generally accepted that mitochondrial reactive oxygen species (ROS) balance depends on the both rate of single electron reduction of O2 to superoxide (O2.-) by the electron transport chain and the rate of scavenging by intracellular antioxidant pathways, considerable controversy exists regarding the conditions leading to oxidative stress in intact cells versus isolated mitochondria. Here, we postulate that mitochondria have been evolutionarily optimized to maximize energy output while keeping ROS overflow to a minimum by operating in an intermediate redox state. We show that at the extremes of reduction or oxidation of the redox couples involved in electron transport (NADH/NAD+) or ROS scavenging (NADPH/NADP+, GSH/GSSG), respectively, ROS balance is lost. This results in a net overflow of ROS that increases as one moves farther away from the optimal redox potential. At more reduced mitochondrial redox potentials, ROS production exceeds scavenging, while under more oxidizing conditions (e.g., at higher workloads) antioxidant defenses can be compromised and eventually overwhelmed. Experimental support for this hypothesis is provided in both cardiomyocytes and in isolated mitochondria from guinea pig hearts. The model reconciles, within a single framework, observations that isolated mitochondria tend to display increased oxidative stress at high reduction potentials (and high mitochondrial membrane potential, Psim), whereas intact cardiac cells can display oxidative stress either when mitochondria become more uncoupled (i.e., low Psim) or when mitochondria are maximally reduced (as in ischemia or hypoxia). The continuum described by the model has the potential to account for many disparate experimental observations and also provides a rationale for graded physiological ROS signaling at redox potentials near the minimum. PMID:20175987

Aon, M A; Cortassa, S; O'Rourke, B

2010-01-01

144

Protecting Against Post-influenza Bacterial Pneumonia by Increasing Phagocyte Recruitment and ROS Production.  

Science.gov (United States)

Seasonal and especially pandemic influenza predispose patients to secondary bacterial pneumonias, which are a major cause of deaths and morbidity. Staphylococcus aureus is a particularly common and deadly form of post-influenza pneumonia, and increasing staphylococcal drug resistance makes the development of new therapies urgent. We explored an innate immune-mediated model of the lung to define novel mechanisms by which the host can be protected against secondary staphylococcal pneumonia after sub-lethal influenza infection. We found that stimulating the innate immunity in the lung by overexpression of GM-CSF will result in resistance to S. aureus pneumonia after sublethal influenza infection. Resistance was mediated by alveolar macrophages and neutrophils, and was associated with increased production of reactive oxygen species (ROS) by alveolar macrophages. Resistance was abrogated by treatment with agents that scavenged ROS. We conclude that stimulating innate immunity in the lung markedly reduces susceptibility to post-influenza staphylococcal pneumonia and that this may represent a novel immunomodulatory strategy for prevention and treatment of secondary bacterial pneumonia after influenza. PMID:24367039

Subramaniam, Renuka; Barnes, Peter F; Fletcher, Kalyn; Boggaram, Vijay; Hillberry, Zachary; Neuenschwander, Pierre; Shams, Homayoun

2014-06-01

145

Hypoxia Triggers AMPK Activation through Reactive Oxygen Species-Mediated Activation of Calcium Release-Activated Calcium Channels ?  

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AMP-activated protein kinase (AMPK) is an energy sensor activated by increases in [AMP] or by oxidant stress (reactive oxygen species [ROS]). Hypoxia increases cellular ROS signaling, but the pathways underlying subsequent AMPK activation are not known. We tested the hypothesis that hypoxia activates AMPK by ROS-mediated opening of calcium release-activated calcium (CRAC) channels. Hypoxia (1.5% O2) augments cellular ROS as detected by the redox-sensitive green fluorescent protein (roGFP) but...

2011-01-01

146

MITOCHONDRIAL REACTIVE OXYGEN SPECIES (ROS AS SIGNALLING MOLECULES OF INTRACELLULAR PATHWAYS TRIGGERED BY THE CARDIAC RENIN-ANGIOTENSIN II-ALDOSTERONE SYSTEM (RAAS.  

Directory of Open Access Journals (Sweden)

Full Text Available Mitochondria represent major sources of basal reactive oxygen species (ROS production of the cardiomyocyte. The role of ROS as signalling molecules that mediate different intracellular pathways has gained increasing interest among physiologists in the last years. In our lab, we have been studying the participation of mitochondrial ROS in the intracellular pathways triggered by the renin-angiotensin II-aldosterone system (RAAS in the myocardium during the past few years. We have demonstrated that acute activation of cardiac RAAS induces mitochondrial ATP-dependent potassium channel (mitoKATP opening with the consequent enhanced production of mitochondrial ROS. These oxidant molecules, in turn, activate membrane transporters, as sodium/hydrogen exchanger (NHE-1 and sodium/bicarbonate cotransporter (NBC via the stimulation of the ROS-sensitive MAPK cascade. The stimulation of such effectors leads to an increase in cardiac contractility. In addition, it is feasible to suggest that a sustained enhanced production of mitochondrial ROS induced by chronic cardiac RAAS, and hence, chronic NHE-1 and NBC stimulation, would also result in the development of cardiac hypertrophy.

ErnestoAlejandroAiello

2013-05-01

147

Aged Garlic Extract Reduces ROS Production and Cell Death Induced by 6-Hydroxydopamine through Activation of the Nrf2-ARE Pathway in SH-SY5Y Cells  

Directory of Open Access Journals (Sweden)

Full Text Available Many degenerative or pathological processes, such as aging, cancer and coronary heart disease, are related to reactive oxygen species (ROS and radical-mediated reactions. We examined the effectiveness of aged garlic extract (AGE, a garlic preparation rich in water-soluble cysteinyl moieties, for protection of cells from ROS produced by 6-hydroxy-dopamine (6-OHDA using human neuroblastoma SH-SY5Y cells. Concomitant treatment of cells with AGE (2 and 4 mg/ml showed the dose-dependent protective effect on the cell death induced by 6-OHDA. In addition, the AGE treatment significantly suppressed the increase of ROS generation by 6-OHDA. Furthermore, the protective effect of AGE was accompanied by activation of the nuclear factor erythroid 2-related factor 2 (Nrf2-antioxidant response element (ARE pathway and the increase of mRNAs of heme oxygenase-1 and NAD(PH quinone oxidoreductase 1. These two enzymes are important in the cellular antioxidant system. These results indicated that AGE protected cells from ROS damage by not only capturing ROS directly but also activating the cellular antioxidant system by stimulating antioxidant gene expression via the Nrf2-ARE pathway. The present study suggested that AGE may be useful for prevention and treatment of cell damage caused by ROS.

Tomoko Fukuuchi

2013-01-01

148

Surfactin-induced apoptosis through ROS-ERS-Ca2+-ERK pathways in HepG2 cells.  

Science.gov (United States)

Although surfactin is able to inhibit cancer cell proliferation and to induce cancer cell apoptosis, the molecular mechanism responsible for this process remain elusive. In this study, the signaling network underlying the apoptosis of human hepatoma (HepG2) cells induced by surfactin was investigated. It is found that the reaction oxygen species (ROS) production and intracellular calcium ([Ca(2+)]i) accumulation are both induced HepG2 cells apoptosis. The [Ca(2+)]i exaltation was partly depended on the Ca(2+) release from inositol 1,4,5-trisphosphate (IP3) and ryanodine (Ry) receptors channels, which both triggered endoplasmic reticulum stress (ERS). The results showed that surfactin induced the ROS production and ROS production led to ERS. The occurrence of ERS increased the [Ca(2+)]i level and the processes associated with blocking extracellular signal-regulated kinase (ERK) pathway. According to a comprehensive review of all the evidence, it is concluded that surfactin induces apoptosis of HepG2 cells through a ROS-ERS-Ca(2+) mediated ERK pathway. PMID:23733672

Wang, Chun-ling; Liu, Chuan; Niu, Li-li; Wang, Li-rui; Hou, Li-hua; Cao, Xiao-hong

2013-12-01

149

Reactive oxygen species (ROS) induced cytokine production and cytotoxicity of PAMAM dendrimers in J774A.1 cells  

International Nuclear Information System (INIS)

The immunotoxicity of three generations of polyamidoamine (PAMAM) dendrimers (G-4, G-5 and G-6) was evaluated in mouse macrophage cells in vitro. Using the Alamar blue and MTT assays, a generation dependent cytotoxicity of the PAMAM dendrimers was found whereby G-6 > G-5 > G-4. The toxic response of the PAMAM dendrimers correlated well with the number of surface primary amino groups, with increasing number resulting in an increase in toxic response. An assessment of intracellular ROS generation by the PAMAM dendrimers was performed by measuring the increased fluorescence as a result of intracellular oxidation of Carboxy H2DCFDA to DCF both quantitatively using plate reader and qualitatively by confocal laser scanning microscopy. The inflammatory mediators macrophage inflammatory protein-2 (MIP-2), tumour necrosis factor-? (TNF-?) and interleukin-6, (IL-6) were measured by the enzyme linked immunosorbant assay (ELISA) following exposure of mouse macrophage cells to PAMAM dendrimers. A generation dependent ROS and cytokine production was found, which correlated well with the cytotoxicological response and therefore number of surface amino groups. A clear time sequence of increased ROS generation (maximum at ? 4 h), TNF-? and IL-6 secretion (maximum at ? 24 h), MIP-2 levels and cell death (? 72 h) was observed. The intracellular ROS generation and cytokine production induced cytotoxicity point towards the mechanistic pathway of cell death upon exposure to PAMAM dendrimers.

2010-07-01

150

Genistein Inhibits Osteoclastic Differentiation of RAW 264.7 Cells via Regulation of ROS Production and Scavenging  

Directory of Open Access Journals (Sweden)

Full Text Available Genistein, a phytoestrogen, has been demonstrated to have a bone-sparing and antiresorptive effect. Genistein can inhibit the osteoclast formation of receptor activator of nuclear factor-?B ligand (RANKL-induced RAW 264.7 cells by preventing the translocation of nuclear factor-?B (NF-?B, a redox-sensitive factor, to the nucleus. Therefore, the suppressive effect of genistein on the reactive oxygen species (ROS level during osteoclast differentiation and the mechanism associated with the control of ROS levels by genistein were investigated. The cellular antioxidant capacity and inhibitory effect of genistein were confirmed. The translation and activation of nicotinamide adenine dinucleotide phosphate (NADPH oxidase 1 (Nox1, as well as the disruption of the mitochondrial electron transport chain system were obviously suppressed by genistein in a dose-dependent manner. The induction of phase II antioxidant enzymes, such as superoxide dismutase 1 (SOD1 and heme oxygenase-1 (HO-1, was enhanced by genistein. In addition, the translational induction of nuclear factor erythroid 2-related factor 2 (Nrf2 was notably increased by genistein. These results provide that the inhibitory effects of genistein on RANKL-stimulated osteoclast differentiation is likely to be attributed to the control of ROS generation through suppressing the translation and activation of Nox1 and the disruption of the mitochondrial electron transport chain system, as well as ROS scavenging through the Nrf2-mediated induction of phase II antioxidant enzymes, such as SOD1 and HO-1.

Sang-Hyun Lee

2014-06-01

151

Genistein Inhibits Osteoclastic Differentiation of RAW 264.7 Cells via Regulation of ROS Production and Scavenging.  

Science.gov (United States)

Genistein, a phytoestrogen, has been demonstrated to have a bone-sparing and antiresorptive effect. Genistein can inhibit the osteoclast formation of receptor activator of nuclear factor-?B ligand (RANKL)-induced RAW 264.7 cells by preventing the translocation of nuclear factor-?B (NF-?B), a redox-sensitive factor, to the nucleus. Therefore, the suppressive effect of genistein on the reactive oxygen species (ROS) level during osteoclast differentiation and the mechanism associated with the control of ROS levels by genistein were investigated. The cellular antioxidant capacity and inhibitory effect of genistein were confirmed. The translation and activation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 1 (Nox1), as well as the disruption of the mitochondrial electron transport chain system were obviously suppressed by genistein in a dose-dependent manner. The induction of phase II antioxidant enzymes, such as superoxide dismutase 1 (SOD1) and heme oxygenase-1 (HO-1), was enhanced by genistein. In addition, the translational induction of nuclear factor erythroid 2-related factor 2 (Nrf2) was notably increased by genistein. These results provide that the inhibitory effects of genistein on RANKL-stimulated osteoclast differentiation is likely to be attributed to the control of ROS generation through suppressing the translation and activation of Nox1 and the disruption of the mitochondrial electron transport chain system, as well as ROS scavenging through the Nrf2-mediated induction of phase II antioxidant enzymes, such as SOD1 and HO-1. PMID:24927148

Lee, Sang-Hyun; Kim, Jin-Kyoung; Jang, Hae-Dong

2014-01-01

152

Cadmium induces autophagy through ROS-dependent activation of the LKB1-AMPK signaling in skin epidermal cells  

International Nuclear Information System (INIS)

Cadmium is a toxic heavy metal which is environmentally and occupationally relevant. The mechanisms underlying cadmium-induced autophagy are not yet completely understood. The present study shows that cadmium induces autophagy, as demonstrated by the increase of LC3-II formation and the GFP-LC3 puncta cells. The induction of autophagosomes was directly visualized by electron microscopy in cadmium-exposed skin epidermal cells. Blockage of LKB1 or AMPK by siRNA transfection suppressed cadmium-induced autophagy. Cadmium-induced autophagy was inhibited in dominant-negative AMPK-transfected cells, whereas it was accelerated in cells transfected with the constitutively active form of AMPK. mTOR signaling, a negative regulator of autophagy, was downregulated in cadmium-exposed cells. In addition, cadmium generated reactive oxygen species (ROS) at relatively low levels, and caused poly(ADP-ribose) polymerase-1 (PARP) activation and ATP depletion. Inhibition of PARP by pharmacological inhibitors or its siRNA transfection suppressed ATP reduction and autophagy in cadmium-exposed cells. Furthermore, cadmium-induced autophagy signaling was attenuated by either exogenous addition of catalase and superoxide dismutase, or by overexpression of these enzymes. Consequently, these results suggest that cadmium-mediated ROS generation causes PARP activation and energy depletion, and eventually induces autophagy through the activation of LKB1-AMPK signaling and the down-regulation of mTOR in skin epidermal cells. - Highlights: ? Cadmium, a toxic heavy metal, induces autophagic cell death through ROS-dependent activation of the LKB1-AMPK signaling. ? Cadmium generates intracellular ROS at low levels and this leads to severe DNA damage and PARP activation, resulting in ATP depletion, which are the upstream events of LKB1-AMPK-mediated autophagy. ? This novel finding may contribute to further understanding of cadmium-mediated diseases.

2011-09-15

153

Interfering with ROS Metabolism in Cancer Cells: The Potential Role of Quercetin  

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A main feature of cancer cells, when compared to normal ones, is a persistent pro-oxidative state that leads to an intrinsic oxidative stress. Cancer cells have higher levels of reactive oxygen species (ROS) than normal cells, and ROS are, in turn, responsible for the maintenance of the cancer phenotype. Persistent ROS stress may induce adaptive stress responses, enabling cancer cells to survive with high levels of ROS and maintain cellular viability. However, excessive ROS levels render canc...

Lara Gibellini; Marcello Pinti; Milena Nasi; Sara De Biasi; Erika Roat; Linda Bertoncelli; Andrea Cossarizza

2010-01-01

154

Lithium Chloride Suppresses Colorectal Cancer Cell Survival and Proliferation through ROS/GSK-3?/NF-?B Signaling Pathway  

Science.gov (United States)

Glycogen synthase kinase-3? (GSK-3?), a serine/threonine protein kinase, has been regarded as a potential therapeutic target for multiple human cancers. In addition, oxidative stress is closely related to all aspects of cancer. We sought to determine the biological function of lithium, one kind of GSK-3? inhibitors, in the process of reactive oxygen species (ROS) production in colorectal cancer. In this study, we analyzed the cell apoptosis and proliferation by cell viability, EdU, and flow cytometry assays through administration of LiCl. We used polymerase chain reaction and Western blotting to establish the effect of GSK-3? inhibition on the nuclear factor-?B (NF-?B) pathway. Results showed administration of LiCl increased apoptosis and the level of ROS in colorectal cancer cells. Furthermore, the underlying mechanisms could be mediated by the reduction of NF-?B expression and NF-?B-mediated transcription. Taken together, our results demonstrated that therapeutic targeting of ROS/GSK-3?/NF-?B pathways may be an effective way for colorectal cancer intervention, although further preclinical and clinical testing are desirable.

Li, Huili; Huang, Kun; Liu, Xinghua; Liu, Jinlin; Lu, Xiaoming; Tao, Kaixiong; Wang, Guobin; Wang, Jiliang

2014-01-01

155

NO, ROS, and cell death associated with caspase-like activity increase in stress-induced microspore embryogenesis of barley  

Science.gov (United States)

Under specific stress treatments (cold, starvation), in vitro microspores can be induced to deviate from their gametophytic development and switch to embryogenesis, forming haploid embryos and homozygous breeding lines in a short period of time. The inductive stress produces reactive oxygen species (ROS) and nitric oxide (NO), signalling molecules mediating cellular responses, and cell death, modifying the embryogenic microspore response and therefore, the efficiency of the process. This work analysed cell death, caspase 3-like activity, and ROS and NO production (using fluorescence probes and confocal analysis) after inductive stress in barley microspore cultures and embryogenic suspension cultures, as an in vitro system which permitted easy handling for comparison. There was an increase in caspase 3-like activity and cell death after stress treatment in microspore and suspension cultures, while ROS increased in non-induced microspores and suspension cultures. Treatments of the cultures with a caspase 3 inhibitor, DEVD-CHO, significantly reduced the cell death percentages. Stress-treated embryogenic suspension cultures exhibited high NO signals and cell death, while treatment with S-nitrosoglutathione (NO donor) in control suspension cultures resulted in even higher cell death. In contrast, in microspore cultures, NO production was detected after stress, and, in the case of 4-day microspore cultures, in embryogenic microspores accompanying the initiation of cell divisions. Subsequent treatments of stress-treated microspore cultures with ROS and NO scavengers resulted in a decreasing cell death during the early stages, but later they produced a delay in embryo development as well as a decrease in the percentage of embryogenesis in microspores. Results showed that the ROS increase was involved in the stress-induced programmed cell death occurring at early stages in both non-induced microspores and embryogenic suspension cultures; whereas NO played a dual role after stress in the two in vitro systems, one involved in programmed cell death in embryogenic suspension cultures and the other in the initiation of cell division leading to embryogenesis in reprogrammed microspores.

Rodriguez-Serrano, Maria; Barany, Ivett; Prem, Deepak; Coronado, Maria-Jose; Risueno, Maria C.; Testillano, Pilar S.

2012-01-01

156

Influenza A virus and TLR7 activation potentiate NOX2 oxidase-dependent ROS production in macrophages.  

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Abstract Influenza A virus infects resident alveolar macrophages in the respiratory tract resulting in Toll like receptor 7 (TLR7) activation that triggers an inflammatory response to resolve the infection. Macrophages are also major sources of reactive oxygen species (ROS) via the NOX2-containing NADPH oxidase. Although ROS are crucial for pathogen clearance, in response to influenza A virus, ROS are touted as being culprit mediators of the lung tissue injury. The aim of the present study was to determine whether influenza A virus infection and TLR7 activation of macrophages, results in alterations in their ROS production. Here we demonstrate using immunofluorescence that influenza A virus (Hong Kong X-31 strain; H3N2) internalizes in RAW264.7 cells and mouse alveolar macrophages within 1 h, resulting in a significant enhancement in the stimulated NOX2 oxidase-dependent oxidative burst, although virus had no effect on basal ROS. The specific TLR7 agonist imiquimod (10 ?g/ml) elevated basal superoxide production and, in a similar fashion to influenza A virus, enhanced NOX2 oxidase-dependent oxidative burst. By contrast, the TLR3 agonist, poly I:C (1-100 ?g/ml) failed to influence the oxidative burst to NOX2 oxidase. A peptide corresponding to the region 337-348 on p47phox conjugated to a HIV-tat, designed to inhibit the phosphorylation of Ser346 on p47phox suppressed the influenza A virus- and imiquimod-induced enhancement in the oxidative burst. In conclusion, this study demonstrates for the first time that influenza A virus and TLR7 activation enhance the NOX2 oxidase-dependent oxidative burst in macrophages, which might underpin the acute lung injury to influenza A virus infection. PMID:24869957

To, E E; Broughton, B R S; Hendricks, K S; Vlahos, R; Selemidis, S

2014-08-01

157

Inhibition of Telomerase Activity by Oleanane Triterpenoid CDDO-Me in Pancreatic Cancer Cells is ROS-Dependent  

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Full Text Available Methyl-2-cyano-3,12-dioxooleana-1,9(11-dien-28-oate (CDDO-Me is a synthetic derivative of oleanolic acid, a triterpene, with apoptosis-inducing activity in a wide range of cancer cells. Induction of apoptosis by CDDO-Me is associated with the generation of reactive oxygen species (ROS and inhibition of telomerase activity. In the present study, we investigated the role of ROS in inhibition of telomerase by CDDO-me. Treatment of MiaPaCa-2 and Panc-1 pancreatic cancer cell lines with CDDO-Me induced the production of hydrogen peroxide and superoxide anions and inhibited the telomerase activity. Pretreatment of cells with N-acetylcycsteine, a general purpose antioxidant or overexpression of glutathione peroxidase (GPx or superoxide dismutase-1 (SOD-1 blocked the telomerase inhibitory activity of CDDO-Me. Furthermore, blocking ROS generation also prevented the inhibition of hTERT gene expression, hTERT protein production and expression of a number of hTERT–regulatory proteins by CDDO-Me (e.g., c-Myc, Sp1, NF-?B and p-Akt. Data also showed that Akt plays an important role in the activation of telomerase activity. Together, these data suggest that inhibition of telomerase activity by CDDO-Me is mediated through a ROS-dependent mechanism; however, more work is needed to fully understand the role of ROS in down-regulation of hTERT gene and hTERT-regulatory proteins by CDDO-Me.

Subhash C. Gautam

2013-03-01

158

Surveillance-activated defenses block the ROS-induced mitochondrial unfolded protein response.  

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Disturbance of cellular functions results in the activation of stress-signaling pathways that aim at restoring homeostasis. We performed a genome-wide screen to identify components of the signal transduction of the mitochondrial unfolded protein response (UPR(mt)) to a nuclear chaperone promoter. We used the ROS generating complex I inhibitor paraquat to induce the UPR(mt), and we employed RNAi exposure post-embryonically to allow testing genes whose knockdown results in embryonic lethality. We identified 54 novel regulators of the ROS-induced UPR(mt). Activation of the UPR(mt), but not of other stress-signaling pathways, failed when homeostasis of basic cellular mechanisms such as translation and protein transport were impaired. These mechanisms are monitored by a recently discovered surveillance system that interprets interruption of these processes as pathogen attack and depends on signaling through the JNK-like MAP-kinase KGB-1. Mutation of kgb-1 abrogated the inhibition of ROS-induced UPR(mt), suggesting that surveillance-activated defenses specifically inhibit the UPR(mt) but do not compromise activation of the heat shock response, the UPR of the endoplasmic reticulum, or the SKN-1/Nrf2 mediated response to cytosolic stress. In addition, we identified PIFK-1, the orthologue of the Drosophila PI 4-kinase four wheel drive (FWD), and found that it is the only known factor so far that is essential for the unfolded protein responses of both mitochondria and endoplasmic reticulum. This suggests that both UPRs may share a common membrane associated mechanism. PMID:23516373

Runkel, Eva D; Liu, Shu; Baumeister, Ralf; Schulze, Ekkehard

2013-01-01

159

Mitochondrial ROS and radiation induced transformation in mouse embryonic fibroblasts  

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Manganese superoxide dismutase (SOD2) is a nuclear encoded and mitochondria localized antioxidant enzyme that converts mitochondria derived superoxide to hydrogen peroxide. This study investigates the hypothesis that mitochondria derived reactive oxygen species (ROS) regulate ionizing radiation (IR) induced transformation in normal cells. Mouse embryonic fibroblasts (MEFs) with wild type SOD2 (+/+), heterozygous SOD2 (+/?), and homozygous SOD2 (?/?) genotypes were irradiated with equito...

2009-01-01

160

The interplay between autophagy and ROS in tumorigenesis  

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Full Text Available Reactive oxygen species (ROS at physiological levels are important cell signaling molecules. However, aberrantly high ROS are intimately associated with disease and commonly observed in cancer. Mitochondria are primary sources of intracellular ROS, and their maintenance is essential to cellular health. Autophagy, an evolutionarily conserved process whereby cytoplasmic components are delivered to lysosomes for degradation, is responsible for mitochondrial turnover and removal of damaged mitochondria. Impaired autophagy is implicated in many pathological conditions, including neurological disorders, inflammatory bowel disease, diabetes, aging and cancer. The first reports connecting autophagy to cancer showed that allelic loss of the essential autophagy gene BECLIN1 (BECN1 is prevalent in human breast, ovarian and prostate cancers and that Becn1+/- mice develop mammary gland hyperplasias, lymphomas, and lung and liver tumors. Subsequent studies demonstrated that Atg5-/- and Atg7-/- livers give rise to adenomas, Atg4-/- mice are susceptible to chemical carcinogenesis, and Bif1-/- mice are prone to spontaneous tumors, indicating that autophagy defects promote tumorigenesis. Due to defective mitophagy, autophagy-deficient cells accumulate damaged mitochondria and deregulated ROS levels, which likely contribute to their tumor-initiating capacity. However, the role of autophagy in tumorigenesis is complex, as more recent work also revealed tumor dependence on autophagy: autophagy-competent mutant-Ras-expressing cells form tumors more efficiently than their autophagy-deficient counterparts; similarly, FIP200 deficiency suppresses PyMT-driven mammary tumorigenesis. These latter findings are attributed to the fact that tumors driven by powerful oncogenes have high metabolic demands catered to by autophagy. In this review, we discuss the relationship between ROS and autophagy and summarize our current knowledge on their functional interactions in tumorigenesis.

VassilikiKarantza

2012-11-01

 
 
 
 
161

Cadmium induces carcinogenesis in BEAS-2B cells through ROS-dependent activation of PI3K/AKT/GSK-3?/?-catenin signaling  

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Cadmium has been widely used in industry and is known to be carcinogenic to humans. Although it is widely accepted that chronic exposure to cadmium increases the incidence of cancer, the mechanisms underlying cadmium-induced carcinogenesis are unclear. The main aim of this study was to investigate the role of reactive oxygen species (ROS) in cadmium-induced carcinogenesis and the signal transduction pathways involved. Chronic exposure of human bronchial epithelial BEAS-2B cells to cadmium induced cell transformation, as evidenced by anchorage-independent growth in soft agar and clonogenic assays. Chronic cadmium treatment also increased the potential of these cells to invade and migrate. Injection of cadmium-stimulated cells into nude mice resulted in the formation of tumors. In contrast, the cadmium-mediated increases in colony formation, cell invasion and migration were prevented by transfection with catalase, superoxide dismutase-1 (SOD1), or SOD2. In particular, chronic cadmium exposure led to activation of signaling cascades involving PI3K, AKT, GSK-3?, and ?-catenin and transfection with each of the above antioxidant enzymes markedly inhibited cadmium-mediated activation of these signaling proteins. Inhibitors specific for AKT or ?-catenin almost completely suppressed the cadmium-mediated increase in total and active ?-catenin proteins and colony formation. Moreover, there was a marked induction of AKT, GSK-3?, ?-catenin, and carcinogenic markers in tumor tissues formed in mice after injection with cadmium-stimulated cells. Collectively, our findings suggest a direct involvement of ROS in cadmium-induced carcinogenesis and implicate a role of AKT/GSK-3?/?-catenin signaling in this process. -- Highlights: ? Chronic exposure to cadmium induces carcinogenic properties in BEAS-2B cells. ? ROS involved in cadmium-induced tumorigenicity of BEAS-2B cells. ? Cadmium activates ROS-dependent AKT/GSK-3?/?-catenin-mediated signaling. ? ROS-dependent signaling as potential therapeutic targets in cadmium carcinogenesis.

2012-10-15

162

protective effects of andrographolide analogue AL-1 on ROS-induced RIN-m? cell death by inducing ROS generation.  

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Oxidative stress is considered to be a major factor contributing to pathogenesis and progression of many diseases. A novel andrographolide-lipoic acid conjugate (AL-1) could protect pancreatic ?-cells from reactive oxygen species (ROS)-induced oxidative injury. However, its protective mechanism is still unclear. In this work, we used proteomics to identify AL-1-regulated proteins in ?-cells and found that 13 of the 71 proteins regulated by AL-1 were closely associated with antioxidation. These differential proteins were mainly involved in the ERK1/2 and AKT1 signaling pathways. Functional investigation demonstrated that AL-1 exerted its protective effects on H2O2-induced cell death of ?-cells by generating NADPH oxidase-dependent ROS to activate ERK1/2 and AKT1 signaling pathways. As a consequence, the expressions of antioxidant proteins including Trx1, Prx1 and Prx5, and anti-apoptotic proteins including PDCD6IP, prohibitin, galectin-1 and HSP were upregulated. AL-1 probably worked as a "vaccinum" to activate the cellular antioxidant system by inducing the generation of low concentration ROS which then reciprocally protected ?-cells from oxidative damage caused by high-level ROS from H2O2. To the best of our knowledge, this is the first comprehensive proteomic analysis illustrating a novel molecular mechanism for the protective effects of antioxidants on ?-cells from H2O2-induced cell death. PMID:23750203

Yan, Guang-Rong; Zhou, Hui-Hua; Wang, Yang; Zhong, Yin; Tan, Zi-Lu; Wang, Yuqiang; He, Qing-Yu

2013-01-01

163

Protective Effects of Andrographolide Analogue AL-1 on ROS-Induced RIN-m? Cell Death by Inducing ROS Generation  

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Oxidative stress is considered to be a major factor contributing to pathogenesis and progression of many diseases. A novel andrographolide-lipoic acid conjugate (AL-1) could protect pancreatic ?-cells from reactive oxygen species (ROS)-induced oxidative injury. However, its protective mechanism is still unclear. In this work, we used proteomics to identify AL-1-regulated proteins in ?-cells and found that 13 of the 71 proteins regulated by AL-1 were closely associated with antioxidation. These differential proteins were mainly involved in the ERK1/2 and AKT1 signaling pathways. Functional investigation demonstrated that AL-1 exerted its protective effects on H2O2-induced cell death of ?-cells by generating NADPH oxidase-dependent ROS to activate ERK1/2 and AKT1 signaling pathways. As a consequence, the expressions of antioxidant proteins including Trx1, Prx1 and Prx5, and anti-apoptotic proteins including PDCD6IP, prohibitin, galectin-1 and HSP were upregulated. AL-1 probably worked as a “vaccinum” to activate the cellular antioxidant system by inducing the generation of low concentration ROS which then reciprocally protected ?-cells from oxidative damage caused by high-level ROS from H2O2. To the best of our knowledge, this is the first comprehensive proteomic analysis illustrating a novel molecular mechanism for the protective effects of antioxidants on ?-cells from H2O2-induced cell death.

Wang, Yang; Zhong, Yin; Tan, Zi-Lu; Wang, Yuqiang; He, Qing-Yu

2013-01-01

164

Un col.loqui poc conegut de Carles Ros [A hardly known col.loqui by Carles Ros  

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Full Text Available This paper deals with the philological edition of a literary text by the 18th c. Valencian grammarian and poet Carles Ros i Hebrera, “Paper graciós, discursiu, enfŕtic, alusiu i sentenciós per a desfresar-se de llaurador a les carnistoltes”. This text is part of a group of humorous “col•loquis” which Ros wrote on the occasion of the carnival. This edition is important since this dialogue has not been recorded in any of the compilations and studies of Ros’ works so far, despite belonging to one of the most popular groups of his works. Moreover, it has lately been listed within the lost or impossible to find works by the famous Valencian author. Finally this edition of the text, which entails several variations when compared to the other editions, is different from those mentioned by the bibliographers. The paper also encloses a study on the importance of the literary and linguistic works by Carles Ros, as well as a philological and literary analysis of the text we are editing.

Martí Mestre, Joaquim

2006-01-01

165

2, 3, 7, 8-Tetrachlorodibenzo-P-dioxin (TCDD) induces premature senescence in human and rodent neuronal cells via ROS-dependent mechanisms.  

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The widespread environmental pollutant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is a potent toxicant that causes significant neurotoxicity. However, the biological events that participate in this process remain largely elusive. In the present study, we demonstrated that TCDD exposure triggered apparent premature senescence in rat pheochromocytoma (PC12) and human neuroblastoma SH-SY5Y cells. Senescence-associated ?-galactosidase (SA-?-Gal) assay revealed that TCDD induced senescence in PC12 neuronal cells at doses as low as 10 nM. TCDD led to F-actin reorganization and the appearance of an alternative senescence marker, ?-H2AX foci, both of which are important features of cellular senescence. In addition, TCDD exposure altered the expression of senescence marker proteins, such as p16, p21 and p-Rb, in both dose- and time-dependent manners. Furthermore, we demonstrated that TCDD promotes mitochondrial dysfunction and the accumulation of cellular reactive oxygen species (ROS) in PC12 cells, leading to the activation of signaling pathways that are involved in ROS metabolism and senescence. TCDD-induced ROS generation promoted significant oxidative DNA damage and lipid peroxidation. Notably, treatment with the ROS scavenger N-acetylcysteine (NAC) markedly attenuated TCDD-induced ROS production, cellular oxidative damage and neuronal senescence. Moreover, we found that TCDD induced a similar ROS-mediated senescence response in human neuroblastoma SH-SY5Y cells. In sum, these results demonstrate for the first time that TCDD induces premature senescence in neuronal cells by promoting intracellular ROS production, supporting the idea that accelerating the onset of neuronal senescence may be an important mechanism underlying TCDD-induced neurotoxic effects. PMID:24587053

Wan, Chunhua; Liu, Jiao; Nie, Xiaoke; Zhao, Jianya; Zhou, Songlin; Duan, Zhiqing; Tang, Cuiying; Liang, Lingwei; Xu, Guangfei

2014-01-01

166

2, 3, 7, 8-Tetrachlorodibenzo-P-Dioxin (TCDD) Induces Premature Senescence in Human and Rodent Neuronal Cells via ROS-Dependent Mechanisms  

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The widespread environmental pollutant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is a potent toxicant that causes significant neurotoxicity. However, the biological events that participate in this process remain largely elusive. In the present study, we demonstrated that TCDD exposure triggered apparent premature senescence in rat pheochromocytoma (PC12) and human neuroblastoma SH-SY5Y cells. Senescence-associated ?-galactosidase (SA-?-Gal) assay revealed that TCDD induced senescence in PC12 neuronal cells at doses as low as 10 nM. TCDD led to F-actin reorganization and the appearance of an alternative senescence marker, ?-H2AX foci, both of which are important features of cellular senescence. In addition, TCDD exposure altered the expression of senescence marker proteins, such as p16, p21 and p-Rb, in both dose- and time-dependent manners. Furthermore, we demonstrated that TCDD promotes mitochondrial dysfunction and the accumulation of cellular reactive oxygen species (ROS) in PC12 cells, leading to the activation of signaling pathways that are involved in ROS metabolism and senescence. TCDD-induced ROS generation promoted significant oxidative DNA damage and lipid peroxidation. Notably, treatment with the ROS scavenger N-acetylcysteine (NAC) markedly attenuated TCDD-induced ROS production, cellular oxidative damage and neuronal senescence. Moreover, we found that TCDD induced a similar ROS-mediated senescence response in human neuroblastoma SH-SY5Y cells. In sum, these results demonstrate for the first time that TCDD induces premature senescence in neuronal cells by promoting intracellular ROS production, supporting the idea that accelerating the onset of neuronal senescence may be an important mechanism underlying TCDD-induced neurotoxic effects.

Nie, Xiaoke; Zhao, Jianya; Zhou, Songlin; Duan, Zhiqing; Tang, Cuiying; Liang, Lingwei; Xu, Guangfei

2014-01-01

167

Implication of intracellular ROS formation, caspase-3 activation and Egr-1 induction in platycodon D-induced apoptosis of U937 human leukemia cells.  

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Platycodon D is a major constituent of triterpene saponins found in the root of Platycodon grandiflorum, Platycodi Radix, which is widely used in traditional Oriental medicine for the treatment of many chronic inflammatory diseases. The results of previous studies have shown that this compound has in vitro growth-inhibitory activity in human cancer cells, however, the mechanism by which this action occurs is poorly understood. In this study, we examined the effects of platycodon D on the production of reactive oxygen species (ROS) and evaluated the association of these effects with apoptotic tumor cell death using a human leukemic U937 cell line. The results of this study demonstrate that platycodon D mediates ROS production, and that this mediation is followed by a decrease in mitochondrial membrane potential (MMP, DJm), activation of caspase-3, and cleavage of poly (ADP-ribose) polymerase (PARP). Both the cytotoxic effects and apoptotic characteristics induced by platycodon D treatment were significantly inhibited by z-DEVD-fmk, a caspase-3 inhibitor, which demonstrates the important role that caspase-3 plays in the observed cytotoxic effect. Additionally, the transcription factor early growth response-1 (Egr-1) gene was transcriptionally activated and the levels of non-steroidal anti-inflammatory drug (NSAID)-activated gene-1 (NAG-1) protein were elevated in platycodon D-treatedU937 cells. However, the quenching of ROS generation in response to treatment with a ROS scavenger, N-acetyl-L-cysteine, reversed the platycodon D-induced apoptosis effects via inhibition of Egr-1 activation, ROS production, MMP collapse, and the subsequent activation of caspase-3. Although further studies are needed to demonstrate that increased expression of Egr-1 by platycodon D leads directly to NAG-1 induction and subsequent apoptosis, our observations clearly indicate that ROS induced through Egr-1 activation are involved in the early molecular events involved in the platycodon D-induced apoptotic pathway. PMID:18804340

Shin, Dong Yeok; Kim, Gi Young; Li, Wei; Choi, Byung Tae; Kim, Nam Deuk; Kang, Ho Sung; Choi, Yung Hyun

2009-02-01

168

No evident dose-response relationship between cellular ROS level and its cytotoxicity - a paradoxical issue in ROS-based cancer therapy  

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Targeting cancer via ROS-based mechanism has been proposed as a radical therapeutic approach. Cancer cells exhibit higher endogenous oxidative stress than normal cells and pharmacological ROS insults via either enhancing ROS production or inhibiting ROS-scavenging activity can selectively kill cancer cells. In this study, we randomly chose 4 cancer cell lines and primary colon or rectal cancer cells from 4 patients to test the hypothesis and obtained following paradoxical results: while piperlongumin (PL) and ?-phenylethyl isothiocyanate (PEITC), 2 well-defined ROS-based anticancer agents, induced an increase of cellular ROS and killed effectively the tested cells, lactic acidosis (LA), a common tumor environmental factor that plays multifaceted roles in promoting cancer progression, induced a much higher ROS level in the tested cancer cells than PL and PEITC, but spared them; L-buthionine sulfoximine (L-BSO, 20??M) depleted cellular GSH more effectively and increased higher ROS level than PL or PEITC but permitted progressive growth of the tested cancer cells. No evident dose-response relationship between cellular ROS level and cytotoxicity was observed. If ROS is the effecter, it should obey the fundamental therapeutic principle – the dose-response relationship. This is a major concern.

Zhu, Chunpeng; Hu, Wei; Wu, Hao; Hu, Xun

2014-01-01

169

No evident dose-response relationship between cellular ROS level and its cytotoxicity - a paradoxical issue in ROS-based cancer therapy.  

Science.gov (United States)

Targeting cancer via ROS-based mechanism has been proposed as a radical therapeutic approach. Cancer cells exhibit higher endogenous oxidative stress than normal cells and pharmacological ROS insults via either enhancing ROS production or inhibiting ROS-scavenging activity can selectively kill cancer cells. In this study, we randomly chose 4 cancer cell lines and primary colon or rectal cancer cells from 4 patients to test the hypothesis and obtained following paradoxical results: while piperlongumin (PL) and ?-phenylethyl isothiocyanate (PEITC), 2 well-defined ROS-based anticancer agents, induced an increase of cellular ROS and killed effectively the tested cells, lactic acidosis (LA), a common tumor environmental factor that plays multifaceted roles in promoting cancer progression, induced a much higher ROS level in the tested cancer cells than PL and PEITC, but spared them; L-buthionine sulfoximine (L-BSO, 20??M) depleted cellular GSH more effectively and increased higher ROS level than PL or PEITC but permitted progressive growth of the tested cancer cells. No evident dose-response relationship between cellular ROS level and cytotoxicity was observed. If ROS is the effecter, it should obey the fundamental therapeutic principle - the dose-response relationship. This is a major concern. PMID:24848642

Zhu, Chunpeng; Hu, Wei; Wu, Hao; Hu, Xun

2014-01-01

170

ROS-industrial: Closing the gap between robotics research and industry  

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In der Publikation wird die ROS Industrial Initiative vorgestellt. Ziel der Initiative ist, das Potential der in der Forschung etablierten Softwareplattform ROS für den Einsatz in industriellen Roboterapplikation zu schöpfen.

Reiser, Ulrich

2013-01-01

171

Clinical Significance of ROS1 Rearrangements in Non-small Cell Lung Cancer  

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Full Text Available Chromosomal rearrangements involving the ROS1 receptor tyrosine kinase gene have recently been described in multiple malignancies, including non-small cell lung cancer (NSCLC. ROS1 rearrangement defines a new molecular subset of NSCLC with the prevalence of ROS1 rearrangements around 1%-2%. ROS1-positive NSCLCs arise in young never-smokers with adenocarcinoma that are similar to those observed in patients with ALK-rearranged NSCLC. Crizotinib demonstrates in vitro activity and early clinical trial shows marked antitumor activity in ROS1-rearranged patients. The overall response rate is around 56% and the disease control rate at 8 weeks is about 76%. Further understanding the ROS1 fusions in the pathogenesis of NSCLC, methods to detect ROS1 rearrangements, and targeting ROS1-rearranged NSCLC patients with specific kinase inhibitors would lead to an era of personalized medicine.

Luting XU

2013-12-01

172

New insights into an old story: Pollen ROS also play a role in hay fever  

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Reactive oxygen species (ROS) can exhibit negative and benign traits. In plants, ROS levels increase markedly during periods of environmental stress, and defense against pathogen attack. ROS form naturally as a by-product of normal oxygen metabolism, and evenly play an essential role in cell growth. The short ROS lifespan makes them ideal molecules to act in cell signaling, a role they share in both plants and animals. A particular plant organism, the pollen grain, may closely interact with h...

Speranza, Anna; Scoccianti, Valeria

2012-01-01

173

Fenretinide induces mitochondrial ROS and inhibits the mitochondrial respiratory chain in neuroblastoma  

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Fenretinide induces apoptosis in neuroblastoma by induction of reactive oxygen species (ROS). In this study, we investigated the role of mitochondria in fenretinide-induced cytotoxicity and ROS production in six neuroblastoma cell lines. ROS induction by fenretinide was of mitochondrial origin, demonstrated by detection of superoxide with MitoSOX, the scavenging effect of the mitochondrial antioxidant MitoQ and reduced ROS production in cells without a functional mitochondrial respiratory cha...

2010-01-01

174

P66SHC and Ageing: ROS and TOR?  

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Both Reactive Oxygen Species (ROS) and hyperactivation of the nutrient-sensing mTOR/S6 kinase cascade have been linked to aging and age-related diseases as well as to the anti-aging effect of calorie restriction. Recent findings that the pro-aging and pro-oxidant molecule p66shc contributes to S6K activation by nutrients and promotes insulin resistance and d...

Pani, Giovambattista

2010-01-01

175

Ligation of CD47 Induces G1 Arrest in EBV-transformed B Cells Through ROS Generation, p38 MAPK/JNK Activation, and Tap73 Upregulation.  

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CD47 is expressed in normal activated cells as well as in several tumors. It also has been implicated as having antiangiogenic and antimetastatic properties, but its roles in Epstein-Barr virus (EBV)-transformed B cells are still not fully understood. Herein, we report that EBV infection induced CD47 surface expression on B cells, and CD47 ligation with anti-CD47 mAb (B6H12) reduced cell proliferation and induced G1 arrest. CD47-induced G1 arrest was mediated through increased cyclin-dependent kinase inhibitors (CDKi) and a simultaneously decreased CDK/cyclins, and p38 MAPK/JNK activation preceded binding of CDKi-CDK. Moreover, reactive oxygen species (ROS) generation and upregulation of both TAp73 and ER stress sensor proteins were detected after CD47 ligation, and p38 inhibitor SB203580 and JNK inhibitor SP600125 blocked upregulation of TAp73 and cell cycle arrest. We investigated whether ROS generation is the initial event of CD47-mediated G1 arrest because ROS scavenger NAC effectively abrogated the majority of CD47-mediated responses but SB203580 and SP600125 did not block ROS production. Taken together, we concluded that CD47 ligation on EBV-transformed B cells led to G1 arrest by ROS generation and, subsequently, there was p38 MAPK/JNK pathway activation, ER stress triggering, and TAp73 upregulation. Our findings provide data supporting CD47 as a feasible target for EBV-associated tumor therapy. PMID:24911792

Park, Ga Bin; Bang, Si Ra; Lee, Hyun-Kyung; Kim, Daejin; Kim, Seonghan; Kim, Jin Kyoung; Kim, Yeong Seok; Hur, Dae Young

2014-01-01

176

Modulation of intercellular ROS signaling of human tumor cells.  

Science.gov (United States)

Tumor cells are resistant against apoptosis-inducing intercellular reactive oxygen species (ROS) signaling but can be resensitized by the inhibition of catalase. Hydrogen peroxide exhibits a dual role in the modulation of intercellular ROS signaling. When suboptimal concentrations of the catalase inhibitior 3-aminotriazole (3-AT) are applied, additional exogenous hydrogen peroxide shifts apoptosis induction to its optimum. When hydrogen peroxide is added at optimal concentrations of 3-AT, or when higher concentrations of 3-AT are applied, the subsequent consumption between HOCl and hydrogen peroxide blunts overall apoptosis induction. These supraoptimal conditions can be brought back to the optimum through excess myeloperoxidase (MPO), partial removal of hydrogen peroxide through the catalase mimetic EUK-134 or partial inhibition of NADPH oxidase. Exogenous nitric oxide (NO) interferes with HOCl signaling through consumption of hydrogen peroxide. Site-specific generation of hydroxyl radicals at the cell membrane of tumor cells induces apoptosis, whereas random HOCl-superoxide anion interaction, and ferrous iron-induced Fenton chemistry of HOCl inhibit intercellular ROS signaling. PMID:20032404

Bechtel, Wibke; Bauer, Georg

2009-11-01

177

Theaflavins retard human breast cancer cell migration by inhibiting NF-kappaB via p53-ROS cross-talk.  

Science.gov (United States)

The present study demonstrates that theaflavins exploit p53 to impede metastasis in human breast cancer cells. Our data suggest that p53-dependent reactive oxygen species (ROS) induce p53-phosphorylation via p38MAPK in a feedback loop to inhibit IkappaBalpha-phosphorylation and NF-kappaB/p65 nuclear translocation, thereby down-regulating the metastatic proteins metalloproteinase (MMP)-2 and MMP-9. When wild-type p53-expressing MCF-7 cells are transfected with p53 short-interfering RNA, or treated with a pharmacological inhibitor of ROS, theaflavins fail to inhibit NF-kappaB-mediated cell migration. On the other hand, NF-kappaB over-expression bestows MCF-7 cells with resistance to the anti-migratory effect of theaflavins. These results indicate that inhibition of NF-kappaB via p53-ROS crosstalk is a pre-requisite for theaflavins to accomplish the anti-migratory effect in breast cancer cells. PMID:19883646

Adhikary, Arghya; Mohanty, Suchismita; Lahiry, Lakshmishri; Hossain, Dewan Md Sakib; Chakraborty, Samik; Das, Tanya

2010-01-01

178

Glucose initially inhibits and later stimulates blood ROS generation  

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Full Text Available Background: Glucose is the main substrate for the generation of NADPH, the cofactor of the oxidative burst enzyme NADPH-oxidase of blood neutrophils. Changes in blood glucose are thus expected to modify the generation of reactive oxygen species (ROS. The new blood ROS generation assay (BRGA quantifies ROS changes induced by blood glucose concentrations as they are found in diabetes mellitus. Material and Methods: Citrated or EDTA blood of 6 healthy donors were analyzed in the BRGA: 10 ?l sample in black polystyrene F-microwells (Brand 781608 were incubated in triplicate with 125 ?l Hanks’ balanced salt solution, 40 ?l 0 - 200 mM glucose in 0.9% NaCl (final added conc.: 0 - 41 mM; final basal glucose conc.: about4 mM, 10 ?l5 mMluminol, and 10 ?l zymosan A (final conc.: 1.9 ?g/ml in 0.9% NaCl. The plates were measured within 0 - 250 min (37? in a photons-multiplyer microtiter plate luminometer (LUmo with an integration time of 1 s. Results: Up to about 30 min reaction time the mean ROS generation was 50% inhibited by about1 mMadded glucose (= approx. IC50. At ?80 min reaction time (possibly necessary for full phosphorylation of glucose to glucose-6-phosphate (G6P, the substrate metabolized by G6P-dehydrogenase to generate NADPH, the cofactor of the NADPH-oxidase the mean ROS generation approximately doubled at about1 mMadded glucose (= approx. SC200 in citrated blood. Discussion: Elevated glucose concentrations not only increase systemic thrombin generation, they can also diminish cellular fibrinolysis and increase systemic inflammation, resulting in a chronic pro-thrombotic state. The fascinating importance of NADPH-oxidases not only in phagocytes but also in the beta cells of pancreas points towards a new pathogenesis explication of diabetes mellitus type 1: whatever stimulus (e.g. a pancreas-tropic virus could activate the beta cell’s autodestructive NADPH-oxidase.

Thomas Stief

2013-02-01

179

Protective Effects of Andrographolide Analogue AL-1 on ROS-Induced RIN-m? Cell Death by Inducing ROS Generation  

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Oxidative stress is considered to be a major factor contributing to pathogenesis and progression of many diseases. A novel andrographolide-lipoic acid conjugate (AL-1) could protect pancreatic ?-cells from reactive oxygen species (ROS)-induced oxidative injury. However, its protective mechanism is still unclear. In this work, we used proteomics to identify AL-1-regulated proteins in ?-cells and found that 13 of the 71 proteins regulated by AL-1 were closely associated with antioxidation. Th...

2013-01-01

180

Damaged DNA Binding Protein 2 in Reactive Oxygen Species (ROS Regulation and Premature Senescence  

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Full Text Available Premature senescence induced by DNA damage or oncogene is a critical mechanism of tumor suppression. Reactive oxygen species (ROS have been implicated in the induction of premature senescence response. Several pathological disorders such as cancer, aging and age related neurological abnormalities have been linked to ROS deregulation. Here, we discuss how Damaged DNA binding Protein-2 (DDB2, a nucleotide excision repair protein, plays an important role in ROS regulation by epigenetically repressing the antioxidant genes MnSOD and Catalase. We further revisit a model in which DDB2 plays an instrumental role in DNA damage induced ROS accumulation, ROS induced premature senescence and inhibition of skin tumorigenesis.

Pradip Raychaudhuri

2012-09-01

 
 
 
 
181

MicroRNA-145 suppresses ROS-induced Ca{sup 2+} overload of cardiomyocytes by targeting CaMKII?  

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Highlights: •CaMKII? mediates H{sub 2}O{sub 2}-induced Ca{sup 2+} overload in cardiomyocytes. •miR-145 can inhibit Ca{sup 2+} overload. •A luciferase assay confirms that miR-145 functions as a CaMKII?-targeting miRNA. •Overexpression of miR-145 regulates CaMKII?-related genes and ameliorates apoptosis. -- Abstract: A change in intracellular free calcium (Ca{sup 2+}) is a common signaling mechanism of reperfusion-induced cardiomyocyte death. Calcium/calmodulin dependent protein kinase II (CaMKII) is a critical regulator of Ca{sup 2+} signaling and mediates signaling pathways responsible for functions in the heart including hypertrophy, apoptosis, arrhythmia, and heart disease. MicroRNAs (miRNA) are involved in the regulation of cell response, including survival, proliferation, apoptosis, and development. However, the roles of miRNAs in Ca{sup 2+}-mediated apoptosis of cardiomyocytes are uncertain. Here, we determined the potential role of miRNA in the regulation of CaMKII dependent apoptosis and explored its underlying mechanism. To determine the potential roles of miRNAs in H{sub 2}O{sub 2}-mediated Ca{sup 2+} overload, we selected and tested 6 putative miRNAs that targeted CaMKII?, and showed that miR-145 represses CaMKII? protein expression and Ca{sup 2+} overload. We confirmed CaMKII? as a direct downstream target of miR-145. Furthermore, miR-145 regulates Ca{sup 2+}-related signals and ameliorates apoptosis. This study demonstrates that miR-145 regulates reactive oxygen species (ROS)-induced Ca{sup 2+} overload in cardiomyocytes. Thus, miR-145 affects ROS-mediated gene regulation and cellular injury responses.

Cha, Min-Ji [Cardiovascular Research Institute, Yonsei University College of Medicine, 250 Seongsanno, Seodamun-gu, Seoul 120-752 (Korea, Republic of); Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, 250 Seongsanno, Seodamun-gu, Seoul 120-752 (Korea, Republic of); Jang, Jin-Kyung [College of Pharmacy, Sookmyung Women’s University, 52 HyoChangWon-Gil, Yongsan-ku, Seoul 140-742 (Korea, Republic of); Ham, Onju; Song, Byeong-Wook; Lee, Se-Yeon [Cardiovascular Research Institute, Yonsei University College of Medicine, 250 Seongsanno, Seodamun-gu, Seoul 120-752 (Korea, Republic of); Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, 250 Seongsanno, Seodamun-gu, Seoul 120-752 (Korea, Republic of); Lee, Chang Yeon; Park, Jun-Hee [Department of Integrated Omics for Biomedical Sciences, Graduate School, Yonsei University, 50 Yonsei-ro, Seodamun-gu, Seoul 120-759 (Korea, Republic of); Lee, Jiyun; Seo, Hyang-Hee [Cardiovascular Research Institute, Yonsei University College of Medicine, 250 Seongsanno, Seodamun-gu, Seoul 120-752 (Korea, Republic of); Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, 250 Seongsanno, Seodamun-gu, Seoul 120-752 (Korea, Republic of); Choi, Eunhyun [Severance Integrative Research Institute for Cerebral and Cardiovascular Disease, Yonsei University Health System, 250 Seongsanno, Seodamun-gu, Seoul 120-752 (Korea, Republic of); Jeon, Woo-min [Department of Animal Resource, Sahmyook University, Seoul 139-742 (Korea, Republic of); Hwang, Hye Jin [Cardiovascular Research Institute, Yonsei University College of Medicine, 250 Seongsanno, Seodamun-gu, Seoul 120-752 (Korea, Republic of); Shin, Hyun-Taek [College of Pharmacy, Sookmyung Women’s University, 52 HyoChangWon-Gil, Yongsan-ku, Seoul 140-742 (Korea, Republic of); and others

2013-06-14

182

MicroRNA-145 suppresses ROS-induced Ca2+ overload of cardiomyocytes by targeting CaMKII?  

International Nuclear Information System (INIS)

Highlights: •CaMKII? mediates H2O2-induced Ca2+ overload in cardiomyocytes. •miR-145 can inhibit Ca2+ overload. •A luciferase assay confirms that miR-145 functions as a CaMKII?-targeting miRNA. •Overexpression of miR-145 regulates CaMKII?-related genes and ameliorates apoptosis. -- Abstract: A change in intracellular free calcium (Ca2+) is a common signaling mechanism of reperfusion-induced cardiomyocyte death. Calcium/calmodulin dependent protein kinase II (CaMKII) is a critical regulator of Ca2+ signaling and mediates signaling pathways responsible for functions in the heart including hypertrophy, apoptosis, arrhythmia, and heart disease. MicroRNAs (miRNA) are involved in the regulation of cell response, including survival, proliferation, apoptosis, and development. However, the roles of miRNAs in Ca2+-mediated apoptosis of cardiomyocytes are uncertain. Here, we determined the potential role of miRNA in the regulation of CaMKII dependent apoptosis and explored its underlying mechanism. To determine the potential roles of miRNAs in H2O2-mediated Ca2+ overload, we selected and tested 6 putative miRNAs that targeted CaMKII?, and showed that miR-145 represses CaMKII? protein expression and Ca2+ overload. We confirmed CaMKII? as a direct downstream target of miR-145. Furthermore, miR-145 regulates Ca2+-related signals and ameliorates apoptosis. This study demonstrates that miR-145 regulates reactive oxygen species (ROS)-induced Ca2+ overload in cardiomyocytes. Thus, miR-145 affects ROS-mediated gene regulation and cellular injury responses

2013-06-14

183

Blunted epidermal L-tryptophan metabolism in vitiligo affects immune response and ROS scavenging by Fenton chemistry, part 1: Epidermal H2O2/ONOO(-)-mediated stress abrogates tryptophan hydroxylase and dopa decarboxylase activities, leading to low serotonin and melatonin levels.  

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Vitiligo is characterized by a progressive loss of inherited skin color. The cause of the disease is still unknown. To date, there is accumulating in vivo and in vitro evidence for massive oxidative stress via hydrogen peroxide (H(2)O(2)) and peroxynitrite (ONOO(-)) in the skin of affected individuals. Autoimmune etiology is the favored theory. Since depletion of the essential amino acid L-tryptophan (Trp) affects immune response mechanisms, we here looked at epidermal Trp metabolism via tryptophan hydroxylase (TPH) with its downstream cascade, including serotonin and melatonin. Our in situ immunofluorescence and Western blot data reveal significantly lower TPH1 expression in patients with vitiligo. Expression is also low in melanocytes and keratinocytes under in vitro conditions. Although in vivo Fourier transform-Raman spectroscopy proves the presence of 5-hydroxytryptophan, epidermal TPH activity is completely absent. Regulation of TPH via microphthalmia-associated transcription factor and L-type calcium channels is severely affected. Moreover, dopa decarboxylase (DDC) expression is significantly lower, in association with decreased serotonin and melatonin levels. Computer simulation supports H(2)O(2)/ONOO(-)-mediated oxidation/nitration of TPH1 and DDC, affecting, in turn, enzyme functionality. Taken together, our data point to depletion of epidermal Trp by Fenton chemistry and exclude melatonin as a relevant contributor to epidermal redox balance and immune response in vitiligo. PMID:22415302

Schallreuter, Karin U; Salem, Mohamed A E L; Gibbons, Nick C J; Martinez, Aurora; Slominski, Radomir; Lüdemann, Jürgen; Rokos, Hartmut

2012-06-01

184

Multiple factors from bradykinin-challenged astrocytes contribute to the neuronal apoptosis: involvement of astroglial ROS, MMP-9, and HO-1/CO system.  

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Bradykinin (BK) has been shown to induce the expression of several inflammatory mediators, including reactive oxygen species (ROS) and matrix metalloproteinases (MMPs), in brain astrocytes. These mediators may contribute to neuronal dysfunction and death in various neurological disorders. However, the effects of multiple inflammatory mediators released from BK-challenged astrocytes on neuronal cells remain unclear. Here, we found that multiple factors were released from brain astrocytes (RBA-1) exposed to BK in the conditioned culture media (BK-CM), including ROS, MMP-9, and heme oxygenase-1 (HO-1)/carbon monoxide (CO), leading to neuronal cell (SK-N-SH) death. Exposure of SK-N-SH cells to BK-CM or H2O2 reduced cell viability and induced cell apoptosis which were attenuated by N-acetyl cysteine, indicating a role of ROS in these responses. The effect of BK-CM on cell viability and cell apoptosis was also reversed by immunoprecipitation of BK-CM with anti-MMP-9 antibody (MMP-9-IP-CM) or MMP2/9 inhibitor, suggesting the involvement of MMP-9 in BK-CM-mediated responses. Astroglial HO-1/CO in BK-CM induced cell apoptosis and reduced cell viability which was reversed by hemoglobin. Consistently, the involvement of CO in these cellular responses was revealed by incubation with a CO donor CO-RM2 which was reversed by hemoglobin. The role of HO-1 in BK-CM-induced responses was confirmed by overexpression of HO-1 in SK-N-SH infected with Adv-HO-1. BK-CM-induced cell apoptosis was due to the activation of caspase-3 and cleavage of PARP. Together, we demonstrate that BK-induced several neurotoxic factors, including ROS, MMP-9, and CO released from astrocytes, may induce neuronal death through a caspase-3-dependent apoptotic pathway. PMID:23307413

Yang, Chuen-Mao; Hsieh, Hsi-Lung; Lin, Chih-Chung; Shih, Ruey-Horng; Chi, Pei-Ling; Cheng, Shin-Ei; Hsiao, Li-Der

2013-06-01

185

ROS constitute a convergence nexus in the development of IGF1 resistance and impaired wound healing in a rat model of type 2 diabetes.  

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An indolent non-healing wound and insulin and/or insulin-like growth factor (IGF1) resistance are cardinal features of diabetes, inflammation and hypercortisolemia. Little is known about why these phenomena occur in so many contexts. Do the various triggers that induce insulin and/or IGF1 resistance and retard wound healing act through a common mechanism? Cultured dermal fibroblasts from rats and full-thickness excisional wounds were used as models to test the premise that reactive oxygen species (ROS) play a causal role in the development of IGF1 resistance and impaired wound healing under different but pathophysiologically relevant clinical settings, including diabetes, dexamethasone-induced hypercortisolemia and TNF?-induced inflammation. In normal fibroblasts, IGF1 initiated a strong degree of phosphorylation of insulin receptor substrate 1 (IRS1) (Tyr612) and Akt (Ser473), concomitantly with increased PI3K activity. This phenomenon seemed to be attenuated in fibroblasts that had phenotypic features of diabetes, inflammation or hypercortisolemia. Notably, these cells also exhibited an increase in the activity of the ROS-phospho-JNK (p-JNK)-p-IRS1 (Ser307) axis. The above-mentioned defects were reflected functionally by attenuation in IGF1-dependent stimulation of key fibroblast functions, including collagen synthesis and cell proliferation, migration and contraction. The effects of IGF1 on glucose disposal and cutaneous wound healing were also impaired in diabetic or hypercortisolemic rats. The ROS suppressors EUK-134 and ?-lipoic acid, or small interfering RNA (siRNA)-mediated silencing of JNK expression, restored IGF1 sensitivity both in vitro and in vivo, and also ameliorated the impairment in IGF1-mediated wound responses during diabetes, inflammation and hypercortisolemia. Our data advance the notion that ROS constitute a convergence nexus for the development of IGF1 resistance and impaired wound healing under different but pathophysiologically relevant clinical settings, with a proof of concept for the beneficial effect of ROS suppressors. PMID:22362362

Bitar, Milad S; Al-Mulla, Fahd

2012-05-01

186

Naegleria fowleri induces MUC5AC and pro-inflammatory cytokines in human epithelial cells via ROS production and EGFR activation.  

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Naegleria fowleri is an amoeboflagellate responsible for the fatal central nervous system (CNS) disease primary amoebic meningoencephalitis (PAM). This amoeba gains access to the CNS by invading the olfactory mucosa and crossing the cribriform plate. Studies using a mouse model of infection have shown that the host secretes mucus during the very early stages of infection, and this event is followed by an infiltration of neutrophils into the nasal cavity. In this study, we investigated the role of N. fowleri trophozoites in inducing the expression and secretion of airway mucin and pro-inflammatory mediators. Using the human mucoepidermal cell line NCI-H292, we demonstrated that N. fowleri induced the expression of the MUC5AC gene and protein and the pro-inflammatory mediators interleukin-8 (IL-8) and interleukin-1 beta (IL-1 beta), but not tumour necrosis factor-alpha or chemokine c-c motif ligand 11 (eotaxin). Since the production of reactive oxygen species (ROS) is a common phenomenon involved in the signalling pathways of these molecules, we analysed if trophozoites were capable of causing ROS production in NCI-H292 cells by detecting oxidation of the fluorescent probe 2,7-dichlorofluorescein diacetate. NCI-H292 cells generated ROS after 15-30 min of trophozoite stimulation. Furthermore, the expression of MUC5AC, IL-8 and IL-1 beta was inhibited in the presence of the ROS scavenger DMSO. In addition, the use of an epidermal growth factor receptor inhibitor decreased the expression of MUC5AC and IL-8, but not IL-1 beta. We conclude that N. fowleri induces the expression of some host innate defence mechanisms, such as mucin secretion (MUC5AC) and local inflammation (IL-8 and IL-1 beta) in respiratory epithelial cells via ROS production and suggest that these innate immune mechanisms probably prevent most PAM infections. PMID:19661176

Cervantes-Sandoval, Isaac; Serrano-Luna, José de Jesús; Meza-Cervantez, Patricia; Arroyo, Rossana; Tsutsumi, Víctor; Shibayama, Mineko

2009-11-01

187

Ursolic acid induces autophagy in U87MG cells via ROS-dependent endoplasmic reticulum stress.  

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Malignant gliomas are the most common primary brain tumors, and novel ways of treating gliomas are urgently needed. Ursolic acid (UA), a pentacyclic triterpenoid, has been reported to exhibit promising antitumor activity. Here, we evaluated the effects of UA on U87MG cells and explored the underlying molecular mechanisms. The results demonstrated that both G1-phase arrest and autophagy were induced by UA in U87MG cells. Evidence of UA-induced autophagy included the formation of acidic vesicular organelles, increase of autophagolysosomes and LC3-II accumulation. UA was also found to induce ER stress and an increase in intracellular calcium accompanied by ROS production. The increase in free cytosolic calcium induced by UA activated the CaMKK-AMPK-mTOR kinase signaling cascade, which ultimately triggered autophagy. Western blot analysis showed that UA promoted the phosphorylation of PERK and eIF2?; this was followed by the upregulation of the downstream protein CHOP, implying the involvement of the ER stress-mediated PERK/eIF2?/CHOP pathway in glioma cells. Meanwhile, UA activated IRE1? and subsequently increased the levels of phosphorylated JNK and Bcl-2, resulting in the dissociation of Beclin1 from Bcl-2. Furthermore, TUDCA and the silencing of either PERK or IRE1? partially blocked the UA-induced accumulation of LC3-II, suggesting that ER stress precedes the process of autophagy. Additionally, NAC attenuated the UA-induced elevation in cytosolic calcium, ER stress markers and autophagy-related proteins, indicating that UA triggered ER stress and autophagy via a ROS-dependent pathway. Collectively, our findings revealed a novel cellular mechanism triggered by UA and provide a molecular basis for developing UA into a drug candidate. PMID:24802810

Shen, Shuying; Zhang, Yi; Zhang, Rui; Tu, Xintao; Gong, Xingguo

2014-07-25

188

Ziyuglycoside II induces cell cycle arrest and apoptosis through activation of ROS/JNK pathway in human breast cancer cells.  

Science.gov (United States)

Ziyuglycoside II, a triterpenoid saponin compound extracted from Sanguisorba officinalis L., has been reported to have a wide range of clinical applications including anti-cancer effect. In this study, the anti-proliferative effect of ziyuglycoside II in two classic human breast cancer cell lines, MCF-7 and MDA-MB-231, was extensively investigated. Our study indicated that ziyuglycoside II could effectively induce G2/M phase arrest and apoptosis in both cell lines. Cell cycle blocking was associated with the down-regulation of Cdc25C, Cdc2, cyclin A and cyclin B1 as well as the up-regulation of p21/WAF1, phospho-Cdc25C and phospho-Cdc2. Ziyuglycoside II treatment also induced reactive oxygen species (ROS) production and apoptosis by activating the extrinsic/Fas/FasL pathway as well as the intrinsic/mitochondrial pathway. More importantly, the c-Jun NH2-terminal kinase (JNK), a downstream target of ROS, was found to be a critical mediator of ziyuglycoside II-induced cell apoptosis. Further knockdown of JNK by siRNA could inhibit ziyuglycoside II-mediated apoptosis with attenuating the up-regulation of Bax and Fas/FasL as well as the down-regulation of Bcl-2. Taken together, the cell death of breast cancer cells in response to ziyuglycoside II was dependent upon cell cycle arrest and cell apoptosis via a ROS-dependent JNK activation pathway. Our findings may significantly contribute to the understanding of the anti-proliferative effect of ziyuglycoside II, in particular to breast carcinoma and provide novel insights into the potential application of such compound in breast cancer therapy. PMID:24680927

Zhu, Xue; Wang, Ke; Zhang, Kai; Zhu, Ling; Zhou, Fanfan

2014-05-16

189

Redirecting apoptosis to aponecrosis induces selective cytotoxicity to pancreatic cancer cells through increased ROS, decline in ATP levels, and VDAC.  

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Pancreatic cancer cell lines with mutated ras underwent an alternative form of cell death (aponecrosis) when treated concomitantly with clinically achievable concentrations of arsenic trioxide, ascorbic acid, and disulfiram (Antabuse; AAA). AAA's major effects are mediated through generation of intracellular reactive oxygen species (ROS) and more than 50% decline in intracellular ATP. N-acetyl cysteine and a superoxide dismutase mimetic prevented aponecrosis and restored intracellular ATP levels. DIDS (4,4'-diisothiocyanatostilbene-2, 2' disulfonic acid), the pan- Voltage-Dependent Anion Channel (VDAC), -1, 2, 3 inhibitor and short hairpin RNA (shRNA) to VDAC-1 blocked cell death and ROS accumulation. In vivo exposure of AAA led to a 62% reduction in mean tumor size and eliminated tumors in 30% of nude mice with PANC-1 xenografts. We concluded that early caspase-independent apoptosis was shifted to VDAC-mediated "targeted" aponecrosis by the addition of disulfiram to arsenic trioxide and ascorbic acid. Conceptually, this work represents a paradigm shift where switching from apoptosis to aponecrosis death pathways, also known as targeted aponecrosis, could be utilized to selectively kill pancreatic cancer cells resistant to apoptosis. PMID:24126434

Dinnen, Richard D; Mao, Yuehua; Qiu, Wanglong; Cassai, Nicholas; Slavkovich, Vesna N; Nichols, Gwen; Su, Gloria H; Brandt-Rauf, Paul; Fine, Robert L

2013-12-01

190

Soybean-derived glyceollins induce apoptosis through ROS generation.  

Science.gov (United States)

Glyceollins, which are synthesized from daidzein in soybeans infected with fungi, have been shown to have anti-fungal effects and antioxidant properties. However, the anti-proliferative mechanism of glyceollins against tumor cells is unknown. Glyceollin-induced apoptosis was evidenced by a decrease in cell viability and mitochondrial membrane potential, and an increase in early redistribution of plasma membrane phosphatidylserine, the sub G1 phase, and DNA fragmentation in hepa1c1c7 cells. Western blot analysis showed that treatment of the hepa1c1c7 cells with the glyceollins decreased the expression of pro-caspase-3, Bcl-2, and cell cycle-related proteins, but increased the expression of p21 and p27, and cytochrome C release into cytosol. At a concentration of 6 ?g mL(-1) or higher, glyceollins significantly stimulated the production of reactive oxygen species (ROS), which appear to be responsible for the apoptotic activity of the compounds. Our present study demonstrated that the high dose of glyceollins possibly caused apoptosis in mouse hepatoma cells through the production of ROS, suggesting the potential to exploit glyceollins as anti-tumorigenic agents. PMID:24513878

Kim, Hyo Jung; Jung, Chae Lim; Jeong, Yeon Shin; Kim, Jong-Sang

2014-04-01

191

Non-Thermal Atmospheric Pressure Plasma Preferentially Induces Apoptosis in p53-Mutated Cancer Cells by Activating ROS Stress-Response Pathways  

Science.gov (United States)

Non-thermal atmospheric pressure plasma (NTAPP) is an ionized gas at room temperature and has potential as a new apoptosis-promoting cancer therapy that acts by generating reactive oxygen species (ROS). However, it is imperative to determine its selectivity and standardize the components and composition of NTAPP. Here, we designed an NTAPP-generating apparatus combined with a He gas feeding system and demonstrated its high selectivity toward p53-mutated cancer cells. We first determined the proper conditions for NTAPP exposure to selectively induce apoptosis in cancer cells. The apoptotic effect of NTAPP was greater for p53-mutated cancer cells; artificial p53 expression in p53-negative HT29 cells decreased the pro-apoptotic effect of NTAPP. We also examined extra- and intracellular ROS levels in NTAPP-treated cells to deduce the mechanism of NTAPP action. While NTAPP-mediated increases in extracellular nitric oxide (NO) did not affect cell viability, intracellular ROS increased under NTAPP exposure and induced apoptotic cell death. This effect was dose-dependently reduced following treatment with ROS scavengers. NTAPP induced apoptosis even in doxorubicin-resistant cancer cell lines, demonstrating the feasibility of NTAPP as a potent cancer therapy. Collectively, these results strongly support the potential of NTAPP as a selective anticancer treatment, especially for p53-mutated cancer cells.

Ma, Yonghao; Ha, Chang Seung; Hwang, Seok Won; Lee, Hae June; Kim, Gyoo Cheon; Lee, Kyo-Won; Song, Kiwon

2014-01-01

192

Chlorella Induces Stomatal Closure via NADPH Oxidase-Dependent ROS Production and Its Effects on Instantaneous Water Use Efficiency in Vicia faba  

Science.gov (United States)

Reactive oxygen species (ROS) have been established to participate in stomatal closure induced by live microbes and microbe-associated molecular patterns (MAMPs). Chlorella as a beneficial microorganism can be expected to trigger stomatal closure via ROS production. Here, we reported that Chlorella induced stomatal closure in a dose-and time-dependent manner in epidermal peels of Vicia faba. Using pharmacological methods in this work, we found that the Chlorella-induced stomatal closure was almost completely abolished by a hydrogen peroxide (H2O2) scavenger, catalase (CAT), significantly suppressed by an NADPH oxidase inhibitor, diphenylene iodonium chloride (DPI), and slightly affected by a peroxidase inhibitor, salicylhydroxamic acid (SHAM), suggesting that ROS production involved in Chlorella-induced stomatal closure is mainly mediated by DPI-sensitive NADPH oxidase. Additionally, Exogenous application of optimal concentrations of Chlorella suspension improved instantaneous water use efficiency (WUEi) in Vicia faba via a reduction in leaf transpiration rate (E) without a parallel reduction in net photosynthetic rate (Pn) assessed by gas-exchange measurements. The chlorophyll fluorescence and content analysis further demonstrated that short-term use of Chlorella did not influence plant photosynthetic reactions center. These results preliminarily reveal that Chlorella can trigger stomatal closure via NADPH oxidase-dependent ROS production in epidermal strips and improve WUEi in leave levels.

Li, Yan; Xu, Shan-Shan; Gao, Jing; Pan, Sha; Wang, Gen-Xuan

2014-01-01

193

ROS generate dalle NAD(P)H ossidasi nella segnalazione redox in linee cellulari leucemiche  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Discovery of the Nox family has led to the concept that ROS are “intentionally” generated and are biologically functional in various cell types. Over the last decades, ROS have been shown to be involved in several physiological and pathological processes and ROS producing enzymes have been suggested as a target for drug development. The mechanism involved in the prosurvival effect of cytokines on the human acute myeloid leukaemia cell lines M07e and B1647 is investigated. A decrease in i...

2011-01-01

194

Production of ROS and its effects on mitochondrial and nuclear DNA, human spermatozoa, and sperm function  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Over the past few decades many researchers studying the causes of male infertility have recently focused on the role played by reactive oxygen species (ROS) – highly reactive oxidizing agents belonging to the class of free radicals. If ROS levels rise, oxidative stress (OS) occurs, which results in oxygen and oxygen derived oxidants, and in turn increases the rates of cellular damage. In human, ROS are produced by a variety of semen components, and antioxidants in the seminal fluid keep ...

2007-01-01

195

Doxorubicin acts via mitochondrial ROS to stimulate catabolism in C2C12 myotubes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Doxorubicin, a commonly prescribed chemotherapeutic agent, causes skeletal muscle wasting in cancer patients undergoing treatment and increases mitochondrial reactive oxygen species (ROS) production. ROS stimulate protein degradation in muscle by activating proteolytic systems that include caspase-3 and the ubiquitin-proteasome pathway. We hypothesized that doxorubicin causes skeletal muscle catabolism through ROS, causing upregulation of E3 ubiquitin ligases and caspase-3. We tested this hyp...

Gilliam, Laura A. A.; Moylan, Jennifer S.; Patterson, Elaine W.; Smith, Jeffrey D.; Wilson, Anne S.; Rabbani, Zaheen; Reid, Michael B.

2012-01-01

196

Rho GTPases and Nox dependent ROS production in skin. Is there a connection?  

DEFF Research Database (Denmark)

Rho GTPases are a family of small GTP binding proteins most commonly known for the regulation of many cellular processes, including actin cytoskeleton re-organisation, cell proliferation, signal transduction and regulation of apoptosis. Additionally, a link between Rho GTPases and reactive oxygen species (ROS) has been shown. In line with the growing interest in the role of ROS in cell biology, the relevance of this connection is becoming increasingly clearer. ROS production is classically associated with oxidative metabolic pathways (e.g. respiratory chain, arachidonic acid). During these metabolic pathways, ROS are produced as by-products and these can be potentially toxic. However, numerous cell types contain dedicated enzymatic complexes, i.e., NADPH oxidase (Nox) complexes, for regulated production of ROS. This regulated production of ROS seems to be important for a number of fundamental cell biological processes, including cell growth, differentiation, migration, angiogenesis, aimed at maintaining tissue homeostasis. Data suggests that skin cells are capable of a regulated ROS production via Nox complexes. Members of the Rho GTPase family have been found to play a central regulatory role in Nox activity. In the present review we will focus on the involvement of Rho GTPases in regulated production of ROS with special emphasis on the skin. We will also discuss the possibility that some in vivo effects of the deletion of members of the Rho GTPase family in skin cells could potentially be linked to a reduced ability of regulated ROS production.

Stanley, Alanna; Hynes, Ailish

2012-01-01

197

Expression and rearrangement of the ROS1 gene in human glioblastoma cells  

Energy Technology Data Exchange (ETDEWEB)

The human ROS1 gene, which possibly encodes a growth factor receptor, was found to be expressed in human tumor cell lines. In a survey of 45 different human cell lines, the authors found ROS1 to be expressed in glioblastoma-derived cell lines at high levels and not to be expressed at all, or expressed at very low levels, in the remaining cell lines. The ROS1 gene was present in normal copy numbers in all cell lines that expressed the gene. However, in one particular glioblastoma line, they detected a potentially activating mutation at the ROS1 locus.

Birchmeier, C.; Sharma, S.; Wigler, M.

1987-12-01

198

Effects of osteotropic hormones on the nitric oxide production in culture of ROS17/2.8 cells  

Energy Technology Data Exchange (ETDEWEB)

We performed the present study to investigate whether osteotropic hormones play roles on the nitric oxide (NO) production in culture of ROS17/2.8 osteoblastic cells. The osteoblastic cell line ROS17/2.8 cells were cultured in F12 medium supplemented with 5% fetal bovine serum (FBS) at 37.deg. C in a humidified atmosphere of 5% CO{sub 2} in air. ROS17/2.8 cells were plated in 96-well plants at a density of 2-3 x 10{sup 3} cells/well and grown to confluence. Then the cells were pretreated with osteotropic hormones (parathyroid hormone (PTH) 20-500 ng/mL, 1, 25-dihydroxycholecalciferol (1, 25[OH]{sub 2}D{sub 3}) 1-100nM ; prostaglandin E{sub 2}(PGE{sub 2}) 20-500 ng/mL) in the medium supplemented with 0.4% FBS for (72 hours and the cells were treated with cytokines (TNF{alpha} and IFN{gamma}) in phenol red-free F12 medium for an additional 48 hours. NO synthesis was assessed by measuring the nitrite anion concentration, the reation product of NO, in the cell culture medium using Griess reagent. PTH and 1, 25[OH]{sub 2}D{sub 4} pretreatment induced a significant increase in NO production in the presence of TNF{alpha} and IFN{gamma}. PGE{sub 2} slightly induced NO production compared to the control group. But, PGE{sub 2} pretreatment did not affect in NO production in the presence of TNF{alpha} and IFN{gamma}. These results suggest that the actions of osteotropic hormones in bone metabolism may be partially mediated by NO in the presence of cytokines.

Ko, Seon Yil; Kim, Min Sung; Han, Won Jeong; Kim, Se Won; Kim, Jung Keun [Dankook University College of Medicine, Seoul (Korea, Republic of)

2005-09-15

199

Transcriptomics and Functional Genomics of ROS-Induced Cell Death Regulation by RADICAL-INDUCED CELL DEATH1  

Science.gov (United States)

Plant responses to changes in environmental conditions are mediated by a network of signaling events leading to downstream responses, including changes in gene expression and activation of cell death programs. Arabidopsis thaliana RADICAL-INDUCED CELL DEATH1 (RCD1) has been proposed to regulate plant stress responses by protein-protein interactions with transcription factors. Furthermore, the rcd1 mutant has defective control of cell death in response to apoplastic reactive oxygen species (ROS). Combining transcriptomic and functional genomics approaches we first used microarray analysis in a time series to study changes in gene expression after apoplastic ROS treatment in rcd1. To identify a core set of cell death regulated genes, RCD1-regulated genes were clustered together with other array experiments from plants undergoing cell death or treated with various pathogens, plant hormones or other chemicals. Subsequently, selected rcd1 double mutants were constructed to further define the genetic requirements for the execution of apoplastic ROS induced cell death. Through the genetic analysis we identified WRKY70 and SGT1b as cell death regulators functioning downstream of RCD1 and show that quantitative rather than qualitative differences in gene expression related to cell death appeared to better explain the outcome. Allocation of plant energy to defenses diverts resources from growth. Recently, a plant response termed stress-induced morphogenic response (SIMR) was proposed to regulate the balance between defense and growth. Using a rcd1 double mutant collection we show that SIMR is mostly independent of the classical plant defense signaling pathways and that the redox balance is involved in development of SIMR.

Salojarvi, Jarkko; Cui, Fuqiang; Sipari, Nina; Leppala, Johanna; Lamminmaki, Airi; Tomai, Gloria; Narayanasamy, Shaman; Reddy, Ramesha A.; Keinanen, Markku; Overmyer, Kirk; Kangasjarvi, Jaakko

2014-01-01

200

Effects of osteotropic hormones on the nitric oxide production in culture of ROS17/2.8 cells  

International Nuclear Information System (INIS)

We performed the present study to investigate whether osteotropic hormones play roles on the nitric oxide (NO) production in culture of ROS17/2.8 osteoblastic cells. The osteoblastic cell line ROS17/2.8 cells were cultured in F12 medium supplemented with 5% fetal bovine serum (FBS) at 37.deg. C in a humidified atmosphere of 5% CO2 in air. ROS17/2.8 cells were plated in 96-well plants at a density of 2-3 x 103 cells/well and grown to confluence. Then the cells were pretreated with osteotropic hormones (parathyroid hormone (PTH) 20-500 ng/mL, 1, 25-dihydroxycholecalciferol (1, 25[OH]2D3) 1-100nM ; prostaglandin E2(PGE2) 20-500 ng/mL) in the medium supplemented with 0.4% FBS for (72 hours and the cells were treated with cytokines (TNF? and IFN?) in phenol red-free F12 medium for an additional 48 hours. NO synthesis was assessed by measuring the nitrite anion concentration, the reation product of NO, in the cell culture medium using Griess reagent. PTH and 1, 25[OH]2D4 pretreatment induced a significant increase in NO production in the presence of TNF? and IFN?. PGE2 slightly induced NO production compared to the control group. But, PGE2 pretreatment did not affect in NO production in the presence of TNF? and IFN?. These results suggest that the actions of osteotropic hormones in bone metabolism may be partially mediated by NO in the presence of cytokines

2005-09-01

 
 
 
 
201

ROS-mediated activation of NF-?B and Foxo during muscle disuse  

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We examined reactive oxygen species as upstream activators of NF-?B and Foxo in skeletal muscle during disuse atrophy. Catalase, an enzyme that degrades H2O2, was overexpressed in soleus muscles via plasmid injection prior to seven days of hind limb immobilization. The increased catalase activity abolished immobilization-induced transactivation of both NF-?B and Foxo, and it attenuated the loss of muscle mass. Thus, H2O2 may be an important initiator of these signaling pathways which lead t...

Dodd, Stephen L.; Gagnon, Brittany J.; Senf, Sarah M.; Hain, Brian A.; Judge, Andrew R.

2010-01-01

202

ROS-mediated genotoxicity of asbestos-cement in mammalian lung cells in vitro  

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Asbestos is a known carcinogen and co-carcinogen. It is a persisting risk in our daily life due to its use in building material as asbestos-cement powder. The present study done on V79-cells (Chinese hamster lung cells) demonstrates the cytotoxic and genotoxic potential of asbestos-cement powder (ACP) in comparison with chrysotile asbestos. A co-exposure of chrysotile and ACP was tested using the cell viability test and the micronucleus assay. The kinetochore analysis had been used to analys...

Dopp, Elke; Yadav, Santosh; Ansari, Furquan Ahmad; Bhattacharya, Kunal; Von Recklinghausen, Ursula; Rauen, Ursula; Ro?delsperger, Klaus; Shokouhi, Behnaz; Geh, Stefan; Rahman, Qamar

2005-01-01

203

ROS-mediated genotoxicity of asbestos-cement in mammalian lung cells in vitro  

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Full Text Available Abstract Asbestos is a known carcinogen and co-carcinogen. It is a persisting risk in our daily life due to its use in building material as asbestos-cement powder. The present study done on V79-cells (Chinese hamster lung cells demonstrates the cytotoxic and genotoxic potential of asbestos-cement powder (ACP in comparison with chrysotile asbestos. A co-exposure of chrysotile and ACP was tested using the cell viability test and the micronucleus assay. The kinetochore analysis had been used to analyse the pathway causing such genotoxic effects. Thiobarbituric acid-reactive substances were determined as evidence for the production of reactive oxygen species. Both, asbestos cement as well as chrysotile formed micronuclei and induced loss of cell viability in a concentration- and time- dependent way. Results of TBARS analysis and iron chelator experiments showed induction of free radicals in ACP- and chrysotile exposed cultures. CaSO4 appeared to be a negligible entity in enhancing the toxic potential of ACP. The co-exposure of both, ACP and chrysotile, showed an additive effect in enhancing the toxicity. The overall study suggests that asbestos-cement is cytotoxic as well as genotoxic in vitro. In comparison to chrysotile the magnitude of the toxicity was less, but co-exposure increased the toxicity of both.

Rödelsperger Klaus

2005-10-01

204

Withaferin A Synergizes the Therapeutic Effect of Doxorubicin through ROS-Mediated Autophagy in Ovarian Cancer  

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Application of doxorubicin (Dox) for the treatment of cancer is restricted due to its severe side effects. We used combination strategy by combining doxorubicin (Dox) with withaferin A (WFA) to minimize the ill effects of Dox. Treatment of various epithelial ovarian cancer cell lines (A2780, A2780/CP70 and CaOV3) with combination of WFA and Dox (WFA/DOX) showed a time- and dose-dependent synergistic effect on inhibition of cell proliferation and induction of cell death, thus reducing the dosa...

2012-01-01

205

Antifungal activity of ZnO nanoparticles-the role of ROS mediated cell injury  

Energy Technology Data Exchange (ETDEWEB)

Metal oxide nanoparticles have marked antibacterial activity. The toxic effect of these nanoparticles, such as those comprised of ZnO, has been found to occur due to an interaction of the nanoparticle surface with water, and to increase with a decrease in particle size. In the present study, we tested the ability of ZnO nanoparticles to affect the viability of the pathogenic yeast, Candida albicans (C. albicans). A concentration-dependent effect of ZnO on the viability of C. albicans was observed. The minimal fungicidal concentration of ZnO was found to be 0.1 mg ml{sup -1} ZnO; this concentration caused an inhibition of over 95% in the growth of C. albicans. ZnO nanoparticles also inhibited the growth of C. albicans when it was added at the logarithmic phase of growth. Addition of histidine (a quencher of hydroxyl radicals and singlet oxygen) caused reduction in the effect of ZnO on C. albicans depending on its concentration. An almost complete elimination of the antimycotic effect was achieved following addition of 5 mM of histidine. Exciting the ZnO by visible light increased the yeast cell death. The effects of histidine suggest the involvement of reactive oxygen species, including hydroxyl radicals and singlet oxygen, in cell death. In light of the above results it appears that metal oxide nanoparticles may provide a novel family of fungicidal compounds.

Lipovsky, Anat; Gedanken, Aharon [Department of Chemistry, Kanbar Laboratory for Nanomaterials, Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan 52900 (Israel); Nitzan, Yeshayahu [Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 52900 (Israel); Lubart, Rachel [Department of Chemistry, Bar-Ilan University, Ramat-Gan (Israel)

2011-03-11

206

Resveratrol Induces Premature Senescence in Lung Cancer Cells via ROS-Mediated DNA Damage  

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Resveratrol (RV) is a natural component of red wine and grapes that has been shown to be a potential chemopreventive and anticancer agent. However, the molecular mechanisms underlying RV's anticancer and chemopreventive effects are incompletely understood. Here we show that RV treatment inhibits the clonogenic growth of non-small cell lung cancer (NSCLC) cells in a dose-dependent manner. Interestingly, the tumor-suppressive effect of low dose RV was not associated with any significant changes...

Luo, Hongmei; Yang, Aimin; Schulte, Bradley A.; Wargovich, Michael J.; Wang, Gavin Y.

2013-01-01

207

Roles of dioxins and heavy metals in cancer and neurological diseases using ROS-mediated mechanisms.  

Science.gov (United States)

Oxidants have critical functions inside healthy and unhealthy cells. Deregulated cell cycle and apoptosis, both regulated by oxidative stress, have been described as hallmarks of mitotic (cancer) and postmitotic (neuronal) cells. This review provides an updated revision of the oxidant effects of some environmental contaminants such as dioxins and the heavy metals cadmium, cobalt, and copper. Dioxins exert their toxic actions by acting on phase I and phase II enzymes, such as cytochromes P450, superoxide dismutase, and glutathione peroxidase, promoting cell proliferation, growth arrest, and apoptosis, affecting cancer homeostasis and neuronal function. Heavy metals manifest cytotoxic effects in various cells and tissues, and tight regulation of metals is essential to the health of organisms. Cadmium modulates gene expression and signal transduction and reduces activities of proteins involved in antioxidant defense, interfering with DNA repair and modifying cancer development and brain function. Cobalt provokes generation of reactive oxygen species and DNA damage in cancer cells and brain tissues, altering proliferation and differentiation and causing apoptosis. Copper is a key metal in cell division processes in both normal and tumor cells. Copper also has been shown to have an important role in neurodegenerative diseases such as Alzheimer disease, Parkinson disease, and amyotrophic lateral sclerosis. PMID:20696237

Matés, José M; Segura, Juan A; Alonso, Francisco J; Márquez, Javier

2010-11-15

208

Antifungal activity of ZnO nanoparticles-the role of ROS mediated cell injury  

International Nuclear Information System (INIS)

Metal oxide nanoparticles have marked antibacterial activity. The toxic effect of these nanoparticles, such as those comprised of ZnO, has been found to occur due to an interaction of the nanoparticle surface with water, and to increase with a decrease in particle size. In the present study, we tested the ability of ZnO nanoparticles to affect the viability of the pathogenic yeast, Candida albicans (C. albicans). A concentration-dependent effect of ZnO on the viability of C. albicans was observed. The minimal fungicidal concentration of ZnO was found to be 0.1 mg ml-1 ZnO; this concentration caused an inhibition of over 95% in the growth of C. albicans. ZnO nanoparticles also inhibited the growth of C. albicans when it was added at the logarithmic phase of growth. Addition of histidine (a quencher of hydroxyl radicals and singlet oxygen) caused reduction in the effect of ZnO on C. albicans depending on its concentration. An almost complete elimination of the antimycotic effect was achieved following addition of 5 mM of histidine. Exciting the ZnO by visible light increased the yeast cell death. The effects of histidine suggest the involvement of reactive oxygen species, including hydroxyl radicals and singlet oxygen, in cell death. In light of the above results it appears that metal oxide nanoparticles may provide a novel family of fungicidal compounds.

2011-03-11

209

ROS-mediated genotoxicity of asbestos-cement in mammalian lung cells in vitro.  

Science.gov (United States)

Asbestos is a known carcinogen and co-carcinogen. It is a persisting risk in our daily life due to its use in building material as asbestos-cement powder. The present study done on V79-cells (Chinese hamster lung cells) demonstrates the cytotoxic and genotoxic potential of asbestos-cement powder (ACP) in comparison with chrysotile asbestos. A co-exposure of chrysotile and ACP was tested using the cell viability test and the micronucleus assay. The kinetochore analysis had been used to analyse the pathway causing such genotoxic effects. Thiobarbituric acid-reactive substances were determined as evidence for the production of reactive oxygen species. Both, asbestos cement as well as chrysotile formed micronuclei and induced loss of cell viability in a concentration- and time-dependent way. Results of TBARS analysis and iron chelator experiments showed induction of free radicals in ACP- and chrysotile exposed cultures. CaSO4 appeared to be a negligible entity in enhancing the toxic potential of ACP. The co-exposure of both, ACP and chrysotile, showed an additive effect in enhancing the toxicity. The overall study suggests that asbestos-cement is cytotoxic as well as genotoxic in vitro. In comparison to chrysotile the magnitude of the toxicity was less, but co-exposure increased the toxicity of both. PMID:16209709

Dopp, Elke; Yadav, Santosh; Ansari, Furquan Ahmad; Bhattacharya, Kunal; von Recklinghausen, Ursula; Rauen, Ursula; Rödelsperger, Klaus; Shokouhi, Behnaz; Geh, Stefan; Rahman, Qamar

2005-10-01

210

Mitochondrial Ca2+ and ROS take center stage to orchestrate TNF-?–mediated inflammatory responses  

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Proinflammatory stimuli induce inflammation that may progress to sepsis or chronic inflammatory disease. The cytokine TNF-? is an important endotoxin-induced inflammatory glycoprotein produced predominantly by macrophages and lymphocytes. TNF-? plays a major role in initiating signaling pathways and pathophysiological responses after engaging TNF receptors. In this issue of JCI, Rowlands et al. demonstrate that in lung microvessels, soluble TNF-? (sTNF-?) promotes the shedding of the TNF-...

2011-01-01

211

Role of Mitochondrial Electron Transport Chain Complexes in Capsaicin Mediated Oxidative Stress Leading to Apoptosis in Pancreatic Cancer Cells  

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We evaluated the mechanism of capsaicin-mediated ROS generation in pancreatic cancer cells. The generation of ROS was about 4–6 fold more as compared to control and as early as 1 h after capsaicin treatment in BxPC-3 and AsPC-1 cells but not in normal HPDE-6 cells. The generation of ROS was inhibited by catalase and EUK-134. To delineate the mechanism of ROS generation, enzymatic activities of mitochondrial complex-I and complex-III were determined in the pure mitochondria. Our results show...

2011-01-01

212

ROS evaluation for a series of CNTs and their derivatives using an ESR method with DMPO  

International Nuclear Information System (INIS)

Carbon nanotubes (CNTs) are important materials in advanced industries. It is a concern that pulmonary exposure to CNTs may induce carcinogenic responses. It has been recently reported that CNTs scavenge ROS though non-carbon fibers generate ROS. A comprehensive evaluation of ROS scavenging using various kinds of CNTs has not been demonstrated well. The present work specifically investigates ROS scavenging capabilities with a series of CNTs and their derivatives that were physically treated, and with the number of commercially available CNTs. CNT concentrations were controlled at 0.2 through 0.6 wt%. The ROS scavenging rate was measured by ESR with DMPO. Interestingly, the ROS scavenging rate was not only influenced by physical treatments, but was also dependent on individual manufacturing methods. Ratio of CNTs to DMPO/ hydrogen peroxide is a key parameter to obtain appropriate ROS quenching results for comparison of CNTs. The present results suggest that dangling bonds are not a sole factor for scavenging, and electron transfer on the CNT surface is not clearly determined to be the sole mechanism to explain ROS scavenging.

2013-04-10

213

Mitochondrial ROS production correlates with, but does not directly regulate lifespan in drosophila  

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The Mitochondrial Free Radical Theory of Aging (MFRTA) is currently one of the most widely accepted theories used to explain aging. From MFRTA three basic predictions can be made: long-lived individuals or species should produce fewer mitochondrial Reactive Oxygen Species (mtROS) than short-lived individuals or species; a decrease in mtROS production w...

Sanz, Alberto; Ferna?ndez-ayala, Daniel J. M.; Stefanatos, Rhoda Ka; Jacobs, Howard T.

2010-01-01

214

Cigarette smoke extract upregulates heme oxygenase-1 via PKC/NADPH oxidase/ROS/PDGFR/PI3K/Akt pathway in mouse brain endothelial cells  

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Full Text Available Abstract Background In the brain, the inducible form of heme oxygenase (HO-1 has been recently demonstrated to exacerbate early brain injury produced by intracerebral hemorrhagic stroke which incident rate has been correlated with cigarette smoking previously. Interestingly, cigarette smoke (CS or chemicals present in CS have been shown to induce HO-1 expression in various cell types, including cerebral endothelial cells. However, the mechanisms underlying CS modulating HO-1 protein expression are not completely understood in the brain vessels. Objective The aim of the present study was to investigate the mechanisms underlying CS modulating HO-1 protein expression in cerebral endothelial cells. Methods Cultured cerebral endothelial cells (bEnd.3 were used to investigate whether a particulate phase of cigarette smoke extract (PPCSE regulates HO-1 expression and to investigate the molecular mechanisms involved in HO-1 expression in bEnd.3 cells. Results We demonstrated that PPCSE (30 ?g/ml significantly induced HO-1 protein expression and its enzymatic activity in bEnd.3 cells determined by western blotting and bilirubin formation, respectively. PPCSE-induced HO-1 expression was mediated through phosphatidylcholine phospholipase C (PC-PLC, PKC?, and PI3K/Akt which were observed by pretreatment with their respective pharmacological inhibitors or transfection with dominant negative mutants of PKC? and Akt. ROS scavenger (N-acetyl-L-cysteine, NAC blocked the PPCSE-induced ROS generation and HO-1 expression. Pretreatment with selective inhibitors of PKC? (rottlerin and NADPH oxidase [diphenyleneiodonium chloride (DPI and apocynin (APO] attenuated the PPCSE-induced NADPH oxidase activity, ROS generation, and HO-1 expression. In addition, we found that PPCSE induced PI3K/Akt activation via NADPH oxidase/ROS-dependent PDGFR phosphorylation. Conclusions Taken together, these results suggested that PPCSE-induced HO-1 expression is mediated by a PC-PLC/PKC?/NADPH oxidase-dependent PDGFR/PI3K/Akt pathway in bEnd.3 cells.

Kou Yu

2011-08-01

215

Moderate extracellular acidification inhibits capsaicin-induced cell death through regulating calcium mobilization, NF-{kappa}B translocation and ROS production in synoviocytes  

Energy Technology Data Exchange (ETDEWEB)

Highlights: Black-Right-Pointing-Pointer Moderate extracellular acidification regulates intracellular Ca{sup 2+} mobilization. Black-Right-Pointing-Pointer Moderate acidification activates NF-{kappa}B nuclear translocation in synoviocytes. Black-Right-Pointing-Pointer Moderate acidification depresses the ROS production induced by capsaicin. Black-Right-Pointing-Pointer Moderate acidification inhibits capsaicin-caused synoviocyte death. -- Abstract: We previously show the expression of transient receptor potential vanilloid 1 (TRPV1) in primary synoviocytes from collagen-induced arthritis (CIA) rats. Capsaicin and lowered extracellular pH from 7.4 to 5.5 induce cell death through TRPV1-mediated Ca{sup 2+} entry and reactive oxygen species (ROS) production. However, under the pathological condition in rheumatoid arthritis, the synovial fluid is acidified to a moderate level (about pH 6.8). In the present study, we examined the effects of pH 6.8 on the TRPV1-mediated cell death. Our finding is different or even opposite from what was observed at pH 5.5. We found that the moderate extracellular acidification (from pH 7.4 to 6.8) inhibited the capsaicin-induced Ca{sup 2+} entry through attenuating the activity of TRPV1. In the mean time, it triggered a phospholipse C (PLC)-related Ca{sup 2+} release from intracellular stores. The nuclear translocation of NF-{kappa}B was found at pH 6.8, and this also depends on PLC activation. Moreover, the capsaicin-evoked massive ROS production and cell death were depressed at pH 6.8, both of which are dependent on the activation of PLC and NF-{kappa}B. Taken together, these results suggested that the moderate extracellular acidification inhibited the capsaicin-induced synoviocyte death through regulating Ca{sup 2+} mobilization, activating NF-{kappa}B nuclear translocation and depressing ROS production.

Hu, Fen; Yang, Shuang; Zhao, Dan; Zhu, Shuyan; Wang, Yuxiang [Department of Biophysics, School of Physics and Key Laboratory of Bioactive Materials of Education Ministry, Nankai University, Tianjin 300071 (China); Li, Junying, E-mail: jyli04@nankai.edu.cn [Department of Biophysics, School of Physics and Key Laboratory of Bioactive Materials of Education Ministry, Nankai University, Tianjin 300071 (China)

2012-07-20

216

Mechanistic Investigation of ROS-Induced DNA Damage by Oestrogenic Compounds in Lymphocytes and Sperm Using the Comet Assay  

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Full Text Available Past research has demonstrated that oestrogenic compounds produce strand breaks in the DNA of sperm and lymphocytes via reactive oxygen species (ROS. In the current investigation, sperm and lymphocytes were treated in vitro with oestrogenic compounds (diethylstilboestrol, progesterone, 17?-oestradiol, noradrenaline and triiodotyronine and several aspects of DNA damage were investigated. Firstly, mediation of DNA damage by lipid peroxidation was investigated in the presence of BHA (a lipid peroxidation blocker. BHA reduced the DNA damage generated by 17?-oestradiol and diethylstilboestrol in a statistically significant manner. No effects were observed for sperm. Secondly, the presence of oxidized bases employing FPG and EndoIII were detected for lymphocytes and sperm in the negative control and after 24 h recovery in lymphocytes but not immediately after treatment for both cell types. The successful detection of oxidized bases in the negative control (untreated of sperm provides an opportunity for its application in biomonitoring studies. DNA repair at 24 h after exposure was also studied. A nearly complete recovery to negative control levels was shown in lymphocytes 24 h recovery after oestrogenic exposure and this was statistically significant in all cases. Rapid rejoining of DNA, in a matter of hours, is a characteristic of DNA damaged by ROS.

Diana Anderson

2011-04-01

217

Tetrahydroxystilbene glucoside attenuates MPP+-induced apoptosis in PC12 cells by inhibiting ROS generation and modulating JNK activation.  

Science.gov (United States)

It is known that oxidative stress plays a major role in the progression of Parkinson's disease (PD). Previous studies have suggested that 2,3,5,4'-tetrahydroxystilbene-2-O-beta-D-glucoside (TSG), an active component extracted from a traditional Chinese herb Polygonum multiflorum Thunb., has significant antioxidant and free radical-scavenging activities. This is the first study that investigated the protective effects of TSG against MPP(+)-induced apoptosis in PC12 cells and determined the underlying mechanism. The results showed that incubation of PC12 cells with TSG before exposing them to MPP(+) could significantly decrease cell viability loss and reverse cell apoptosis in a dose-dependent manner. The anti-apoptotic effects of TSG were probably mediated via the inhibition of ROS generation and modulation of JNK activation because TSG blocked ROS increase and JNK phosphorylation induced by MPP(+). Taken together, these results indicated that TSG may provide a useful therapeutic strategy for the treatment of neurodegenerative diseases such as PD. PMID:20643188

Li, Xiaobing; Li, Yan; Chen, Jianzong; Sun, Jing; Li, Xiaofeng; Sun, Xin; Kang, Xiaogang

2010-10-01

218

Evaluation of denture base resin after disinfection method using reactive oxygen species (ROS).  

Science.gov (United States)

The effects of certain disinfectants on the stability of a polymethyl methacrylate denture base resin were investigated, including those of a novel disinfection method using reactive oxygen species (ROS). The surface roughness and flexural strength were analyzed to assess the effects of the disinfectants on material properties. The following disinfectants were tested: 5% sodium hypochlorite, 70% alcohol, and ROS. Furthermore, the attachment of Candida albicans to the resin surface was investigated. The disinfection method using sodium hypochlorite significantly increased the surface roughness and decreased flexural strength. The surface roughness and flexural strength of the ROS-treated specimens did not significantly differ from those of the control specimens, and the ROS-treated specimens exhibited diminished Candida attachment. These results demonstrate that the ROS disinfection method preserves acceptable material stability levels in polymethyl methacrylate resins. PMID:22673458

Odagiri, Ken; Sawada, Tomofumi; Hori, Norio; Seimiya, Kazuhide; Otsuji, Takeshi; Hamada, Nobushiro; Kimoto, Katsuhiko

2012-01-01

219

Reactive oxygen species (ROS) is not a promotor of taxol-induced cytoplasmic vacuolization  

Science.gov (United States)

we have previously reported that taxol, a potent anticancer agent, induces caspase-independent cell death and cytoplasmic vacuolization in human lung adenocarcinoma (ASTC-a-1) cells. However, the mechanisms of taxol-induced cytoplasmic vacuolization are poorly understood. Reactive oxygen species (ROS) has been reported to be involved in the taxol-induced cell death. Here, we employed confocal fluorescence microscopy imaging to explore the role of ROS in taxol-induced cytoplasmic vacuolization. We found that ROS inhibition by addition of N-acetycysteine (NAC), a total ROS scavenger, did not suppress these vacuolization but instead increased vacuolization. Take together, our results showed that ROS is not a promotor of the taxol-induced cytoplasmic vacuolization.

Sun, Qingrui; Chen, Tongsheng

2009-02-01

220

NADPH oxidase/ROS-dependent PYK2 activation is involved in TNF-?-induced matrix metalloproteinase-9 expression in rat heart-derived H9c2 cells.  

Science.gov (United States)

TNF-? plays a mediator role in the pathogenesis of chronic heart failure contributing to cardiac remodeling and peripheral vascular disturbances. The implication of TNF-? in inflammatory responses has been shown to be mediated through up-regulation of matrix metalloproteinase-9 (MMP-9). However, the detailed mechanisms of TNF-?-induced MMP-9 expression in rat embryonic-heart derived H9c2 cells are largely not defined. We demonstrated that in H9c2 cells, TNF-? induced MMP-9 mRNA and protein expression associated with an increase in the secretion of pro-MMP-9. TNF-?-mediated responses were attenuated by pretreatment with the inhibitor of ROS (N-acetyl-l-cysteine, NAC), NADPH oxidase [apocynin (APO) or diphenyleneiodonium chloride (DPI)], MEK1/2 (U0126), p38 MAPK (SB202190), JNK1/2 (SP600125), NF-?B (Bay11-7082), or PYK2 (PF-431396) and transfection with siRNA of TNFR1, p47(phox), p42, p38, JNK1, p65, or PYK2. Moreover, TNF-? markedly induced NADPH oxidase-derived ROS generation in these cells. TNF-?-enhanced p42/p44 MAPK, p38 MAPK, JNK1/2, and NF-?B (p65) phosphorylation and in vivo binding of p65 to the MMP-9 promoter were inhibited by U0126, SB202190, SP600125, NAC, DPI, or APO. In addition, TNF-?-mediated PYK2 phosphorylation was inhibited by NAC, DPI, or APO. PYK2 inhibition could reduce TNF-?-stimulated MAPKs and NF-?B activation. Thus, in H9c2 cells, we are the first to show that TNF-?-induced MMP-9 expression is mediated through a TNFR1/NADPH oxidase/ROS/PYK2/MAPKs/NF-?B cascade. We demonstrated that NADPH oxidase-derived ROS generation is involved in TNF-?-induced PYK2 activation in these cells. Understanding the regulation of MMP-9 expression and NADPH oxidase activation by TNF-? on H9c2 cells may provide potential therapeutic targets of chronic heart failure. PMID:23774252

Yang, Chuen-Mao; Lee, I-Ta; Hsu, Ru-Chun; Chi, Pei-Ling; Hsiao, Li-Der

2013-10-15

 
 
 
 
221

Superoxide-mediated protection of Escherichia coli from antimicrobials.  

Science.gov (United States)

Antimicrobial lethality is promoted by reactive oxygen species (ROS), such as superoxide, peroxide, and hydroxyl radical. Pretreatment with subinhibitory concentrations of plumbagin or paraquat, metabolic generators of superoxide, paradoxically reduced killing for oxolinic acid, kanamycin, and ampicillin. These pretreatments also reduced an oxolinic acid-mediated ROS surge. Defects in SoxS MarA or AcrB eliminated plumbagin- and paraquat-mediated MIC increases but maintained protection from killing. Thus, superoxide has both protective and detrimental roles in response to antimicrobial stress. PMID:23979754

Mosel, Michael; Li, Liping; Drlica, Karl; Zhao, Xilin

2013-11-01

222

Free radicals mediate systemic acquired resistance.  

Science.gov (United States)

Systemic acquired resistance (SAR) is a form of resistance that protects plants against a broad spectrum of secondary infections. However, exploiting SAR for the protection of agriculturally important plants warrants a thorough investigation of the mutual interrelationships among the various signals that mediate SAR. Here, we show that nitric oxide (NO) and reactive oxygen species (ROS) serve as inducers of SAR in a concentration-dependent manner. Thus, genetic mutations that either inhibit NO/ROS production or increase NO accumulation (e.g., a mutation in S-nitrosoglutathione reductase [GSNOR]) abrogate SAR. Different ROS function additively to generate the fatty-acid-derived azelaic acid (AzA), which in turn induces production of the SAR inducer glycerol-3-phosphate (G3P). Notably, this NO/ROS?AzA?G3P-induced signaling functions in parallel with salicylic acid-derived signaling. We propose that the parallel operation of NO/ROS and SA pathways facilitates coordinated regulation in order to ensure optimal induction of SAR. PMID:24726369

Wang, Caixia; El-Shetehy, Mohamed; Shine, M B; Yu, Keshun; Navarre, Duroy; Wendehenne, David; Kachroo, Aardra; Kachroo, Pradeep

2014-04-24

223

Regulation of ROS in transmissible gastroenteritis virus-activated apoptotic signaling  

Energy Technology Data Exchange (ETDEWEB)

Highlights: •TGEV infection induced ROS accumulation. •ROS accumulation is involved in TGEV-induced mitochondrial integrity impairment. •ROS is associated with p53 activation and apoptosis occurrence in TGEV-infected cells. -- Abstract: Transmissible gastroenteritis virus (TGEV), an enteropathogenic coronavirus, causes severe lethal watery diarrhea and dehydration in piglets. Previous studies indicate that TGEV infection induces cell apoptosis in host cells. In this study, we investigated the roles and regulation of reactive oxygen species (ROS) in TGEV-activated apoptotic signaling. The results showed that TGEV infection induced ROS accumulation, whereas UV-irradiated TGEV did not promote ROS accumulation. In addition, TGEV infection lowered mitochondrial transmembrane potential in PK-15 cell line, which could be inhibited by ROS scavengers, pyrrolidinedithiocarbamic (PDTC) and N-acetyl-L-cysteine (NAC). Furthermore, the two scavengers significantly inhibited the activation of p38 MAPK and p53 and further blocked apoptosis occurrence through suppressing the TGEV-induced Bcl-2 reduction, Bax redistribution, cytochrome c release and caspase-3 activation. These results suggest that oxidative stress pathway might be a key element in TGEV-induced apoptosis and TGEV pathogenesis.

Ding, Li [College of Veterinary Medicine, Northwest A and F University, Yangling, Shaanxi 712100 (China); College of Life Sciences, Hainan Normal University, Haikou, Hainan 571158 (China); Zhao, Xiaomin; Huang, Yong; Du, Qian; Dong, Feng; Zhang, Hongling; Song, Xiangjun; Zhang, Wenlong [College of Veterinary Medicine, Northwest A and F University, Yangling, Shaanxi 712100 (China); Tong, Dewen, E-mail: dwtong@nwsuaf.edu.cn [College of Veterinary Medicine, Northwest A and F University, Yangling, Shaanxi 712100 (China)

2013-12-06

224

Regulation of ROS in transmissible gastroenteritis virus-activated apoptotic signaling  

International Nuclear Information System (INIS)

Highlights: •TGEV infection induced ROS accumulation. •ROS accumulation is involved in TGEV-induced mitochondrial integrity impairment. •ROS is associated with p53 activation and apoptosis occurrence in TGEV-infected cells. -- Abstract: Transmissible gastroenteritis virus (TGEV), an enteropathogenic coronavirus, causes severe lethal watery diarrhea and dehydration in piglets. Previous studies indicate that TGEV infection induces cell apoptosis in host cells. In this study, we investigated the roles and regulation of reactive oxygen species (ROS) in TGEV-activated apoptotic signaling. The results showed that TGEV infection induced ROS accumulation, whereas UV-irradiated TGEV did not promote ROS accumulation. In addition, TGEV infection lowered mitochondrial transmembrane potential in PK-15 cell line, which could be inhibited by ROS scavengers, pyrrolidinedithiocarbamic (PDTC) and N-acetyl-L-cysteine (NAC). Furthermore, the two scavengers significantly inhibited the activation of p38 MAPK and p53 and further blocked apoptosis occurrence through suppressing the TGEV-induced Bcl-2 reduction, Bax redistribution, cytochrome c release and caspase-3 activation. These results suggest that oxidative stress pathway might be a key element in TGEV-induced apoptosis and TGEV pathogenesis

2013-12-06

225

Reactive oxygen species (ROS) homeostasis and redox regulation in cellular signaling.  

Science.gov (United States)

Reactive oxygen species (ROS) are generated during mitochondrial oxidative metabolism as well as in cellular response to xenobiotics, cytokines, and bacterial invasion. Oxidative stress refers to the imbalance due to excess ROS or oxidants over the capability of the cell to mount an effective antioxidant response. Oxidative stress results in macromolecular damage and is implicated in various disease states such as atherosclerosis, diabetes, cancer, neurodegeneration, and aging. Paradoxically, accumulating evidence indicates that ROS also serve as critical signaling molecules in cell proliferation and survival. While there is a large body of research demonstrating the general effect of oxidative stress on signaling pathways, less is known about the initial and direct regulation of signaling molecules by ROS, or what we term the "oxidative interface." Cellular ROS sensing and metabolism are tightly regulated by a variety of proteins involved in the redox (reduction/oxidation) mechanism. This review focuses on the molecular mechanisms through which ROS directly interact with critical signaling molecules to initiate signaling in a broad variety of cellular processes, such as proliferation and survival (MAP kinases, PI3 kinase, PTEN, and protein tyrosine phosphatases), ROS homeostasis and antioxidant gene regulation (thioredoxin, peroxiredoxin, Ref-1, and Nrf-2), mitochondrial oxidative stress, apoptosis, and aging (p66Shc), iron homeostasis through iron-sulfur cluster proteins (IRE-IRP), and ATM-regulated DNA damage response. PMID:22286106

Ray, Paul D; Huang, Bo-Wen; Tsuji, Yoshiaki

2012-05-01

226

Fenretinide induces mitochondrial ROS and inhibits the mitochondrial respiratory chain in neuroblastoma.  

Science.gov (United States)

Fenretinide induces apoptosis in neuroblastoma by induction of reactive oxygen species (ROS). In this study, we investigated the role of mitochondria in fenretinide-induced cytotoxicity and ROS production in six neuroblastoma cell lines. ROS induction by fenretinide was of mitochondrial origin, demonstrated by detection of superoxide with MitoSOX, the scavenging effect of the mitochondrial antioxidant MitoQ and reduced ROS production in cells without a functional mitochondrial respiratory chain (Rho zero cells). In digitonin-permeabilized cells, a fenretinide concentration-dependent decrease in ATP synthesis and substrate oxidation was observed, reflecting inhibition of the mitochondrial respiratory chain. However, inhibition of the mitochondrial respiratory chain was not required for ROS production. Co-incubation of fenretinide with inhibitors of different complexes of the respiratory chain suggested that fenretinide-induced ROS production occurred via complex II. The cytotoxicity of fenretinide was exerted through the generation of mitochondrial ROS and, at higher concentrations, also through inhibition of the mitochondrial respiratory chain. PMID:19941060

Cuperus, Roos; Leen, René; Tytgat, Godelieve A M; Caron, Huib N; van Kuilenburg, André B P

2010-03-01

227

Quantification of basal and stimulated ROS levels as predictors of islet potency and function.  

Science.gov (United States)

We have developed a luminol-based assay using intact islets, which allows for quantification of reactive oxygen species (ROS). In addition, an index capable of characterizing metabolic and mitochondrial integrity prior to transplantation was created based on the capacity of islets to respond to high glucose and rotenone (mitochondrial respiratory chain complex I inhibitor) by production of ROS. To validate this assay, lipid peroxidation and antioxidative defense capacity were evaluated by detection of malondialdehyde (MDA) levels and glutathione peroxidase activity (GPx), respectively. Also, flow cytometric analyses of ROS (dihydroethidine), apoptosis (Annexin V, active caspases), necrosis (Topro3), and mitochondrial membrane potential (JC-1) were done in parallel to correlate with changes in luminol-measured ROS. ATP/ADP ratios were quantified by HPLC and the predictive value of ROS measurement on islet functional potency was correlated with capacity to reverse diabetes in a streptozotocin-induced diabetic NOD.scid mouse model as well as in human transplant recipients. Our data demonstrate that levels of ROS in islets correlate with the percentage of apoptotic cells and their functional potency in vivo. The ROS indices following glucose and rotenone exposure are indicative of metabolic potency and mitochondrial integrity and can be used as surrogate markers to evaluate the quality of islets prior to transplantation. PMID:17227556

Armann, B; Hanson, M S; Hatch, E; Steffen, A; Fernandez, L A

2007-01-01

228

TiO{sub 2} nanoparticle-induced ROS correlates with modulated immune cell function  

Energy Technology Data Exchange (ETDEWEB)

Design of non-toxic nanoparticles will be greatly facilitated by understanding the nanoparticle-cell interaction mechanism on a cell function level. Mast cells are important cells for the immune system's first line of defense, and we can utilize their exocytotic behavior as a model cellular function as it is a conserved process across cell types and species. Perturbations in exocytosis can also have implications for whole organism health. One proposed mode of toxicity is nanoparticle-induced reactive oxygen species (ROS), particularly for titanium dioxide (TiO{sub 2}) nanoparticles. Herein, we have correlated changes in ROS with the perturbation of the critical cell function of exocytosis, using UV light to induce greater levels of ROS in TiO{sub 2} exposed cells. The primary culture mouse peritoneal mast cells (MPMCs) were exposed to varying concentrations of TiO{sub 2} nanoparticles for 24 h. ROS content was determined using 2,7-dihydrodichlorofluorescein diacetate (DCFDA). Cellular viability was determined with the MTT and Trypan blue assays, and exocytosis was measured by the analytical electrochemistry technique of carbon-fiber microelectrode amperometry. MPMCs exposed to TiO{sub 2} nanoparticles experienced a dose-dependent increase in total ROS content. While there was minimal impact of ROS on cellular viability, there is a correlation between ROS amount and exocytosis perturbation. As nanoparticle-induced ROS increases, there is a significant decrease (45 %) in the number of serotonin molecules being released during exocytosis, increase (26 %) in the amount of time for each exocytotic granule to release, and decrease (28 %) in the efficiency of granule trafficking and docking. This is the first evidence that nanoparticle-induced ROS correlates with chemical messenger molecule secretion, possibly making a critical connection between functional impairment and mechanisms contributing to that impairment.

Maurer-Jones, Melissa A.; Christenson, Jenna R.; Haynes, Christy L., E-mail: chaynes@umn.edu [University of Minnesota, Department of Chemistry (United States)

2012-12-15

229

Measurements of UV-generated free radicals/reactive oxygen species (ROS) in skin.  

Science.gov (United States)

Free radicals/reactive oxygen species (ROS) generated in skin by UV irradiation were measured by electron spin resonance (ESR). To increase the sensitivity of measurement the short life free radicals/ROS were scavenged and accumulated by using the nitroxyl probe 3-carboxy-2,2,5,5-tetrametylpyrrolidine-1-oxyl (PCA). The spatial distribution of free radicals/ROS measured in pig skin biopsies with ESR imaging after UV irradiation corresponds to the intensity decay of irradiance in the depth of the skin. The main part of free radicals/ROS were generated by UVA (320-400 nm) so that the spatial distribution of free radicals reaches up to the lower side of the dermis. In vivo measurements on human skin were performed with a L-band ESR spectrometer and a surface coil integrating the signal intensities from all skin layers to get a sufficient signal amplitude. Using this experimental arrangement the protection of UVB and UVA/B filter against the generation of free radicals/ROS in skin were measured. The protection against ROS and the repair of damages caused by them can be realized with active antioxidants characterized by a high antioxidative power (AP). The effect of UV filter and antioxidants corresponding to their protection against free radicals/ROS in skin generated by UVAB irradiation can be quantified by the new radical sun protection factor (RSF). The RSF indicates the increase of time for staying in the sun to generate the same number of free radicals/ROS in the skin like for the unprotected skin. Regarding the amount of generated free radicals/ROS in skin as an biophysical endpoint the RSF characterizes both the protection against UVB and UVA radiation. PMID:16543118

Herrling, Th; Jung, K; Fuchs, J

2006-03-13

230

Autophagy inhibition promotes 5-fluorouraci-induced apoptosis by stimulating ROS formation in human non-small cell lung cancer A549 cells.  

Science.gov (United States)

Chemotherapy is an important option for the treatment of various cancers including lung cancer. However, tumor resistance towards cytotoxic chemotherapy has become more common. It has been reported that autophagy is one of the processes contributing to this resistance. In the present study, we found that the anti-cancer drug 5-fluorouraci(5-FU) could induce autophagy in A549 cells. 5-FU treatment could lead to the conversion of LC3 I/II, the up-regulation of Beclin-1, the down-regulation of p62 and the formation of acidic vesicular organelles (AVOs) in A549 cells. Pre-treatment of cancer cells with 3-MA or siAtg7 could enhance 5-FU-induced apoptosis through the activation of caspases, and the caspase inhibitor z-VAD-fmk rescued the cell viability reduction. Furthermore, the inhibition of autophagy also stimulated ROS formation and scavenging of ROS by antioxidant NAC inhibited caspase-3 activity, prevented the release of cyt-c from mitochondria and eventually rescued cancer cells from 5-FU-mediated apoptosis. These results suggest that 5-FU-elicited autophagic response plays a protective role against cell apoptosis and the inhibition of autophagy could sensitize them to 5-FU-induced caspase-dependent apoptosis through the stimulation of ROS formation. PMID:23441212

Pan, Xiaohong; Zhang, Xiuli; Sun, Hongliu; Zhang, Jinjin; Yan, Miaomiao; Zhang, Huaibin

2013-01-01

231

An agonistic antibody to human death receptor 4 induces apoptotic cell death in head and neck cancer cells through mitochondrial ROS generation.  

Science.gov (United States)

The proapoptotic death receptor 4 (DR4), along with DR5, is currently regarded as a promising target for development of agonistic anti-cancer agents due to its tumor-selective apoptosis-inducing ability with no significant cytotoxicity to normal cells. In this study, we examine susceptibility of various head and neck cancer (HNC) cells and mechanism of cell death to an anti-DR4 agonistic monoclonal antibody (mAb), AY4. AY4 as a single agent induced caspase-dependent apoptotic cell death of KB and HN9, but not in SNU899 and FaDu cell lines. AY4 treatment resulted in accumulation of intracellular reactive oxygen species (ROS) generated from mitochondria in AY4-sensitive cells. Blockade of ROS production by N-acetyl-l-cysteine (NAC) resulted in protection of AY4-sensitive cells against AY4-induced apoptosis. ROS generation induced by AY4 treatment triggered down-regulation of anti-apoptotic molecules of Bcl-xL and X-linked inhibitor of apoptosis (XIAP) without affecting the expression levels of DR4, Mcl-1, and survivin. AY4 also inhibited growth of pre-established HN9 tumors in a nude mouse xenograft model and did not show noticeable cytotoxicity in a zebrafish model. Our results provide further insight into the mechanism of DR4-mediated cell death and potential use of AY4 mAb as an anti-cancer therapeutic agent in AY4-sensitive HNC types. PMID:22353688

Lee, Bok-Soon; Kang, Sung Un; Hwang, Hye Sook; Kim, Yong-Sung; Sung, Eun-Sil; Shin, Yoo Seob; Lim, Young Chang; Kim, Chul-Ho

2012-09-01

232

Cross-talk between ROS and calcium in regulation of nuclear activities.  

Science.gov (United States)

Calcium and Reactive Oxygen Species (ROS) are acknowledged as crucial second messengers involved in the response to various biotic and abiotic stresses. However, it is still not clear how these two compounds can play a role in different signaling pathways leading the plant to a variety of processes such as root development or defense against pathogens. Recently, it has been shown that the concept of calcium and ROS signatures, initially discovered in the cytoplasm, can also be extended to the nucleus of plant cells. In addition, it has been clearly proved that both ROS and calcium signals are intimately interconnected. How this cross-talk can finally modulate the translocation and/or the activity of nuclear proteins leading to the control of specific genes expression is the main focus of this review. We will especially focus on how calcium and ROS interact at the molecular level to modify their targets. PMID:20522524

Mazars, Christian; Thuleau, Patrice; Lamotte, Olivier; Bourque, Stéphane

2010-07-01

233

A microfluidic systems biology approach for live single-cell mitochondrial ROS imaging  

Science.gov (United States)

Most current studies of ROS production report globally averaged measurements within the cell; however, ROS can be produced in distinct subcellular locations and have local effects in their immediate vicinity. A microfluidic platform for high-throughput single cell imaging allows mitochondrial ROS production to be monitored as varying in both space and time. Using this systems biology approach, single cell variability can be viewed within a population. We discuss single cell monitoring of contributors to mitochondrial redox state - mitochondrial hydrogen peroxide or superoxide - through the use of a small molecule probe or targeted fluorescent reporter protein. Jurkat T lymphoma cells were stimulated with antimycin A and imaged in an arrayed microfluidic device over time. Differences in single cell responses were observed as a function of both inhibitor concentration and type of ROS measurement used.

Kniss, Ariel; Lu, Hang; Jones, Dean P.; Kemp, Melissa L.

2014-01-01

234

Effect of polychlorinated biphenyls on production of reactive oxygen species (ROS) in rat synaptosomes  

Energy Technology Data Exchange (ETDEWEB)

In this paper the effect of polychlorinated biphenyls (PCBs) on the production of reactive oxygen species (ROS) in rat synaptosomes is elucidated. The effect of methylmercury (MeHg) on rat synaptosomes was included as a positive control since several studies have investigated the ability of this substance to produce ROS. The exposure of the synaptosomes to the congener 2,2-dichlorobiphenyl (2,2'-DCB; 12.5 {mu}M) produced a linear increase in the formation of 2',7'-dichlorofluorescein (DCF) as a measure for the production of ROS. The congeners 2,2'-DCB (12.5 {mu}M) and 3,3'-DCB (12.5 {mu}M) stimulated, as expression of ROS production, a significant increase in DCF formation formation compared to the control. The congeners 2-chlorobiphenyl (2-CB) and 2,2',6-trichlorobiphenyl (2,2,6'-TCB) were active at 50 {mu}M, whereas 2,2',4,4',5,5'-hexachlorobiphenyl (2,2',4,4',5,5'-HCB), 4,4'-DCB and 2,2',6,6'-tetrachlorobiphenyl (2,2',6,6'-TeCB) were not active at this concentration. The increased formation of ROS in response to 2,2'-DCB and MeHg in the synaptosomes was dependent on extracellular Ca{sup 2+}. A phospholipase C inhibitor, U73122, was shown to significantly decrease the ROS formation induced by 2,2'-DCB, but did not reduce the ROS formation induced by MeHg. Ethanol (1%), a phospholipase D modulator, reduced the ROS formation induced by MeHg and by 2,2'-DCB by 33 and 52%, respectively. Wortmannin (25 nM), an inhibitor of phosphatidylinositol 3-kinase, completely inhibited the ROS formation induced by MeHg and 2,2'-DCB. It appears that the ROS-stimulating PCBs are the same congeners found to be neuroactive in other types of study. Phospholipase C and D and phosphatidylinositol 3-kinase seem to be involved in the intracellular signalling system that leads to ROS formation during PCB exposure. (orig.)

Voie, Oe.A.; Fonnum, F. [Norwegian Defence Research Establishment, Div. for Environmental Toxicology, Kjeller (Norway)

2000-01-01

235

Evidence for an adaptation in ROS scavenging systems in human testicular peritubular cells from infertility patients.  

Science.gov (United States)

Fibrosis, increased amounts of immune cells and expression of COX-2 in the testes of infertility patients provide circumstantial evidence for a specific testicular milieu, in which reactive oxygen species (ROS) could be increased. If ROS level increase and/or ROS scavengers decrease, the resulting testicular oxidative stress may contribute to human male infertility. Primary peritubular cells of the human testis, from men with normal spermatogenesis (HTPCs) and infertile patients (HTPC-Fs), previously allowed us to identify an end product of COX-2 action, a prostaglandin derivative (15dPGJ2), which acts via ROS to alter the phenotype of peritubular cells, at least in vitro. Using testicular biopsies we now found 15dPGJ2 in patients and hence we started exploring the ROS scavenger systems of the human testis. This system includes catalase, DJ-1, peroxiredoxin 1, SOD 1 and 2, glutathione-S-transferase and HMOX-1, which were identified by RT-PCR/sequencing in HTPCs and HTPC-Fs and whole testes. Catalase, DJ-1, peroxiredoxin 1 and SOD 2 were also detected by Western blots and in part by immunohistochemistry in testicular samples. Western blots of cultured cells further revealed that catalase levels, but not peroxiredoxin 1, SOD 2 or DJ-1 levels, are significantly higher in HTPC-Fs than in HTPCs. This particular difference is correlated with the improved ability of HTPC-Fs to handle ROS, which became evident when cells were exposed to 100 ?m H(2)O(2). H(2)O(2) induced stronger responses in HTPCs than in HTPC-Fs, which correlates with the lower level of the H(2)O(2)-degrading defence enzyme catalase in HTPCs. The results provide evidence for an adaptation to elevated ROS levels, which must have occurred in vivo and which persist in vitro in HTPC-Fs. Thus, in infertile men with impaired spermatogenesis elevated ROS levels likely exist, at least in the tubular wall. PMID:22640168

Kampfer, C; Spillner, S; Spinnler, K; Schwarzer, J U; Terradas, C; Ponzio, R; Puigdomenech, E; Levalle, O; Köhn, F M; Matzkin, M E; Calandra, R S; Frungieri, M B; Mayerhofer, A

2012-12-01

236

HIV protease inhibitors elicit volume-sensitive Cl? current in cardiac myocytes via mitochondrial ROS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

HIV protease inhibitors (HIV PI) reduce morbidity and mortality of HIV infection but cause multiple untoward effects. Because certain HIV PI evoke production of reactive oxygen species (ROS) and volume-sensitive Cl? current (ICl,swell) is activated by ROS, we tested whether HIV PI stimulate ICl,swell in ventricular myocytes. Ritonavir and lopinavir elicited outwardly-rectifying Cl? currents under isosmotic conditions that were abolished by the selective ICl,swell-blocker DCPIB. In contras...

Deng, Wu; Baki, Lia; Yin, Jun; Zhou, Huiping; Baumgarten, Clive M.

2010-01-01

237

Oleic, Linoleic and Linolenic Acids Increase ROS Production by Fibroblasts via NADPH Oxidase Activation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The effect of oleic, linoleic and ?-linolenic acids on ROS production by 3T3 Swiss and Rat 1 fibroblasts was investigated. Using lucigenin-amplified chemiluminescence, a dose-dependent increase in extracellular superoxide levels was observed during the treatment of fibroblasts with oleic, linoleic and ?-linolenic acids. ROS production was dependent on the addition of ?-NADH or NADPH to the medium. Diphenyleneiodonium inhibited the effect of oleic, linoleic and ?-linolenic acids on fibrobl...

Hatanaka, Elaine; Dermargos, Alexandre; Hirata, Aparecida Emiko; Vinolo, Marco Aure?lio Ramirez; Carpinelli, Angelo Rafael; Newsholme, Philip; Armelin, Hugo Aguirre; Curi, Rui

2013-01-01

238

Forum Original Research Communication: Frataxin, Iron–Sulfur Clusters, Heme, ROS, and Aging  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A deficiency in mitochondrial frataxin causes an increased generation of mitochondrial reactive oxygen species (ROS), which may contribute to the cell degenerative features of Friedreich’s ataxia. In this work the authors demonstrate mitochondrial iron–sulfur cluster (ISC) defects and mitochondrial heme defects, and suggest how both may contribute to increased mitochondrial ROS in lymphoblasts from human patients. Mutant cells are deficient in the ISC-requiring mitochondrial enzymes aconi...

Napoli, Eleonora; Taroni, Franco; Cortopassi, Gino A.

2006-01-01

239

Oncogene-induced Nrf2 transcription promotes ROS detoxification and tumorigenesis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Reactive oxygen species (ROS) are mutagenic and may thereby promote cancer1. Normally, ROS levels are tightly controlled by an inducible antioxidant program that responds to cellular stressors and is predominantly regulated by the transcription factor Nrf2 and its repressor protein Keap12-5. In contrast to the acute physiological regulation of Nrf2, in neoplasia there is evidence for increased basal activation of Nrf2. Indeed, somatic mutations that disrupt the Nrf2-Keap1 interaction to stabi...

Denicola, Gina M.; Karreth, Florian A.; Humpton, Timothy J.; Gopinathan, Aarthi; Wei, Cong; Frese, Kristopher; Mangal, Dipti; Yu, Kenneth H.; Yeo, Charles J.; Calhoun, Eric S.; Scrimieri, Francesca; Winter, Jordan M.; Hruban, Ralph H.; Iacobuzio-donahue, Christine; Kern, Scott E.

2011-01-01

240

Reactive oxygen species (ROS) homeostasis and redox regulation in cellular signaling  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Reactive oxygen species (ROS) are generated during mitochondrial oxidative metabolism as well as in cellular response to xenobiotics, cytokines, and bacterial invasion. Oxidative stress refers to the imbalance due to excess ROS or oxidants over the capability of the cell to mount an effective antioxidant response. Oxidative stress results in macromolecular damage and is implicated in various disease states such as atherosclerosis, diabetes, cancer, neurodegeneration, and aging. Paradoxically,...

Ray, Paul D.; Huang, Bo-wen; Tsuji, Yoshiaki

2012-01-01

 
 
 
 
241

ROS signaling, oxidative stress and Nrf2 in pancreatic beta-cell function  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This review focuses on the emerging evidence that reactive oxygen species (ROS) derived from glucose metabolism, such as H2O2, act as metabolic signaling molecules for glucose-stimulated insulin secretion (GSIS) in pancreatic beta-cells. Particular emphasis is placed on the potential inhibitory role of endogenous antioxidants, which rise in response to oxidative stress, in glucose-triggered ROS and GSIS. We propose that cellular adaptive response to oxidative stress challenge, such as nuclear...

Pi, Jingbo; Zhang, Qiang; Fu, Jingqi; Woods, Courtney G.; Hou, Yongyong; Corkey, Barbara E.; Collins, Sheila; Andersen, Melvin E.

2010-01-01

242

Isofraxidin, a potent reactive oxygen species (ROS) scavenger, protects human leukemia cells from radiation-induced apoptosis via ROS/mitochondria pathway in p53-independent manner.  

Science.gov (United States)

Ionizing radiation (IR) leads to oxidizing events such as excessive reactive oxygen species (ROS) in the exposed cells, resulting in further oxidative damage to lipids, proteins and DNA. To screen the potential radio-protective drug, the intracellular ROS was measured in irradiated U937 cells pretreated with 80 candidate traditional herbal medicine, respectively. Isofraxidin (IF) was one possible radio-protector in these 80 drugs. This study investigated the radio-protective role of IF, a Coumarin compound, in human leukemia cell lines, for the first time. Results indicate that IF protects against IR-induced apoptosis in U937 cells in the time- and concentration- dependent manner. IF decreases IR-induced intracellular ROS generation, especially hydroxyl radicals formation, inhibits IR-induced mitochondrial membrane potential loss and reduces IR-induced high intracellular Ca(2+) levels regardless of ER stress. IF down-regulates the expression of caspase-3, phospho-JNK, phospho-p38 and activates Bax in mitochondria. IF inhibits cytochrome c release from mitochondria to cytosol. IF also moderates IR-induced Fas externalization and caspase-8 activation. IF also exhibits significant protection against IR-induced cell death in other leukemia cell lines such as Molt-4 cells and HL60 cells regardless of p53. Taken together, the data demonstrate that IF protects leukemia cells from radiation-induced apoptosis via ROS/mitochondria pathway in a p53-independent manner. PMID:24692054

Li, Peng; Zhao, Qing-Li; Wu, Li-Hua; Jawaid, Paras; Jiao, Yu-Fei; Kadowaki, Makoto; Kondo, Takashi

2014-06-01

243

Hexokinase II inhibitor, 3-BrPA induced autophagy by stimulating ROS formation in human breast cancer cells  

Science.gov (United States)

Hexokinase II (HKII), a key enzyme of glycolysis, is widely over-expressed in cancer cells. 3-bromopyruvate (3-BrPA), an inhibitor of HK II, has been proposed as a specific antitumor agent. Autophagy is a process that regulates the balance between protein synthesis and protein degradation. Autophagy in mammalian systems occurs under basal conditions and can be stimulated by stresses, including starvation, oxidative stress. Therefore, we hypothesized that 3-BrPA could induce autophagy. In the present study, we explored the mechanism of 3-BrPA and its combined action with chloroquine. Our results demonstrate that in MDA-MB-435 and in MDA-MB-231 cells, 3-BrPA induces autophagy, which can be inhibited by chloroquine. Furthermore, the combined treatment synergistically decreased the number of viable cells. Interestingly, the combined treatment triggered apoptosis in MDA-MB-435 cells, while it induced necroptosis in MDA-MB-231 cells. ROS mediated cell death when 3-BrPA and CQ were co-administered. Finally, CQ enhanced the anticancer efficacy of 3-BrPA in vivo. Collectively, our results show that 3-BrPA triggers autophagy, increasing breast cancer cell resistance to 3-BrPA treatment and that CQ enhanced 3-BrPA-induced cell death in breast cancer cells by stimulating ROS formation. Thus, inhibition of autophagy may be an innovative strategy for adjuvant chemotherapy of breast cancer.human skeletal muscle. Efficient Mirk depletion in SU86.86 pancreatic cancer cells by an inducible shRNA decreased expression of eight antioxidant genes. Thus both cancer cells and differentiated myotubes utilize Mirk kinase to relieve oxidative stress.

Zhang, Qianwen; Zhang, Yuanyuan; Zhang, Pei; Chao, Zhenhua; Xia, Fei; Jiang, Chenchen; Zhang, Xudong; Jiang, Zhiwen; Liu, Hao

2014-01-01

244

Protective effects of (-)-epigallocatechin-3-gallate against TNF-?-induced lung inflammation via ROS-dependent ICAM-1 inhibition.  

Science.gov (United States)

Oxidative stresses are considered to play an important role in the induction of cell adhesion molecules and proinflammatory cytokines implicated in inflammatory processes. Heme oxygenase (HO)-1 and suppressors of cytokine signaling (SOCS)-3 exert several biological functions, including antiapoptotic and anti-inflammatory effects. Here, we report that HO-1 and SOCS-3 were induced in A549 cells and human pulmonary alveolar epithelial cells (HPAEpiCs) treated with (-)-epigallocatechin-3-gallate (EGCG). EGCG protected against tumor necrosis factor (TNF)-?-mediated lung inflammation by down-regulation of oxidative stress and intercellular adhesion molecule (ICAM)-1 expression in A549 cells or HPAEpiCs and the lungs of mice. EGCG inhibited TNF-?-induced ICAM-1 expression, THP-1 cells adherence, pulmonary hematoma and leukocyte (eosinophils and neutrophils) count in bronchoalveolar lavage fluid in mice. In addition, EGCG also attenuated TNF-?-induced oxidative stress, p47(phox) translocation, MAPKs activation, and STAT-3 and activating transcription factor (ATF)2 phosphorylation. EGCG also reduced the formation of a TNFR1/TRAF2/Rac1/p47(phox) complex. Moreover, in this study, the observed suppression of TNF-?-stimulated ICAM-1 expression and reactive oxygen species (ROS) generation by EGCG was abrogated by transfection with siRNA of SOCS-3 or HO-1. These results suggested that HO-1 or SOCS-3 functions as a suppressor of TNF-? signaling, not only by inhibiting adhesion molecules expression but also by diminishing intracellular ROS production and STAT-3 and ATF2 activation in A549 cells or HPAEpiCs and the lungs of mice. PMID:22819551

Lee, I-Ta; Lin, Chih-Chung; Lee, Chi-Yin; Hsieh, Pei-Wen; Yang, Chuen-Mao

2013-01-01

245

Cytotoxic mechanisms of Zn2+ and Cd2+ involve Na+/H+ exchanger (NHE) activation by ROS  

International Nuclear Information System (INIS)

The signaling mechanism induced by cadmium (Cd) and zinc (Zn) in gill cells of Mytilus galloprovincialis was investigated. Both metals cause an increase in ·O2 - production, with Cd to be more potent (216 ± 15%) than Zn (150 ± 9.5%), in relation to control value (100%). The metals effect was reversed after incubation with the amiloride analogue, EIPA, a selective Na+/H+ exchanger (NHE) inhibitor as well as in the presence of calphostin C, a protein kinase C (PKC) inhibitor. The heavy metals effect on ·O2 - production was mediated via the interaction of metal ions with ?1- and ?-adrenergic receptors, as shown after incubation with their respective agonists and antagonists. In addition, both metals caused an increase in intracellular pH (pHi) of gill cells. EIPA together with either metal significantly reduced the effect of each metal treatment on pHi. Incubation of gill cells with the oxidants rotenone, antimycin A and pyruvate caused a significant increase in pHi (?pHi 0.830, 0.272 and 0.610, respectively), while in the presence of the anti-oxidant N-acetyl cysteine (NAC) a decrease in pHi (?pHi -0.090) was measured, indicating that change in reactive oxygen species (ROS) production by heavy metals affects NHE activity. When rosiglitazone was incubated together with either heavy metal a decrease in O2 - production was observed. Our results show a key role of NHE in the signal transduction pathway induced by Zn and Cd in gill cells, with the involvement of ROS, PKC, adrenergic and PPAR-? receptors. In addition, differences between the two metals concerning NHE activation, O2 - production and interaction with adrenergic receptors were observed

2006-07-20

246

ROS Detoxification and Proinflammatory Cytokines Are Linked by p38 MAPK Signaling in a Model of Mature Astrocyte Activation  

Science.gov (United States)

Astrocytes are the most abundant glial cell in the retinal nerve fiber layer (NFL) and optic nerve head (ONH), and perform essential roles in maintaining retinal ganglion cell (RGC) detoxification and homeostasis. Mature astrocytes are relatively quiescent, but rapidly undergo a phenotypic switch in response to insult, characterized by upregulation of intermediate filament proteins, loss of glutamate buffering, secretion of pro-inflammatory cytokines, and increased antioxidant production. These changes result in both positive and negative influences on RGCs. However, the mechanism regulating these responses is still unclear, and pharmacologic strategies to modulate select aspects of this switch have not been thoroughly explored. Here we describe a system for rapid culture of mature astrocytes from the adult rat retina that remain relatively quiescent, but respond robustly when challenged with oxidative damage, a key pathogenic stress associated with inner retinal injury. When primary astrocytes were exposed to reactive oxygen species (ROS) we consistently observed characteristic changes in activation markers, along with increased expression of detoxifying genes, and secretion of proinflammatory cytokines. This in vitro model was then used for a pilot chemical screen to target specific aspects of this switch. Increased activity of p38? and ? Mitogen Activated Protein Kinases (MAPKs) were identified as a necessary signal regulating expression of MnSOD, and heme oxygenase 1 (HO-1), with consequent changes in ROS-mediated injury. Additionally, multiplex cytokine profiling detected p38 MAPK-dependent secretion of IL-6, MCP-1, and MIP-2?, which are proinflammatory signals recently implicated in damage to the inner retina. These data provide a mechanism to link increased oxidative stress to proinflammatory signaling by astrocytes, and establish this assay as a useful model to further dissect factors regulating the reactive switch.

Nahirnyj, Adrian; Livne-Bar, Izhar; Guo, Xiaoxin; Sivak, Jeremy M.

2013-01-01

247

Evidence of reactive oxygen species-mediated damage to mitochondrial DNA in children with typical autism  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract Background The mitochondrial genome (mtDNA) is particularly susceptible to damage mediated by reactive oxygen species (ROS). Although elevated ROS production and elevated biomarkers of oxidative stress have been found in tissues from children with autism spectrum disorders, evidence for damage to mtDNA is lacking. Findings mtDNA deletions were evaluated in peripheral blood monocytic cells (PBMC) isolated from 2–5 year old children with full autism (AU...

Napoli Eleonora; Wong Sarah; Giulivi Cecilia

2013-01-01

248

Osteoblast Adhesion Dynamics: A Possible Role for ROS and LMW-PTP.  

Science.gov (United States)

Reactive oxygen species (ROS) modulate a variety of intracellular events, but their role in osteoblast adhesion and spreading remains unclear. ROS is a very-known physiological modulators of Protein Tyrosine Phosphatases activities, mainly to low molecular weight protein tyrosine phosphatase (LMW-PTP) activity. As this biological mechanism is not clear in osteoblast adhesion, we decided to investigate ROS levels and phosphorylations of FAK and Src, identifying these proteins as potential substrates to LMW-PTP activity. Our results showed that during osteoblast adhesion/spreading (30?min and 2?h of seeding) the intracellular ROS content (hydrogen peroxide) is finely regulated by an effective anti-oxidant system [catalase and Superoxide Dismutase (SOD) activities were evaluated]. During the first 30?min of adhesion, there was an increase in ROS production and a concomitant increase in focal adhesion kinase (FAK) activity after its phosphorylation at Tyrosine 397 (Y397 ). Moreover, after 2?h there was a decrease in ROS content and FAK phosphorylation. There was no significant change in LMW-PTP expression at 30?min or 2?h. In order to validate our hypothesis that LMW-PTP is able to control FAK activity by modulating its phosphorylation status, we decided to overexpress and silence LMW-PTP in this context. Our results showed that FAK phosphorylation at Y397 was increased and decreased in osteoblasts with silenced or overexpressed LMW-PTP, respectively. Together, these data show that ROS modulate FAK phosphorylation by an indirect way, suggesting that a LMW-PTP/FAK supra-molecular complex is involved in transient responses during osteoblast adhesion and spreading. J. Cell. Biochem. 115: 1063-1069, 2014. © 2013 Wiley Periodicals, Inc. PMID:24123071

Fernandes, Gustavo V O; Cavagis, Alexandre D M; Ferreira, Carmen V; Olej, Beni; de Souza Leăo, Maurício; Yano, Cláudia L; Peppelenbosch, Maikel; Granjeiro, José Mauro; Zambuzzi, Willian F

2014-06-01

249

Rapamycin sensitive ROS formation and Na(+)/H(+) exchanger activity in dendritic cells.  

Science.gov (United States)

Rapamycin, a widely used immunosuppressive drug, has been shown to interfere with the function of dendritic cells (DCs), antigen-presenting cells contributing to the initiation of primary immune responses and the establishment of immunological memory. DC function is governed by the Na(+)/H(+) exchanger (NHE), which is activated by bacterial lipopolysaccharides (LPS) and is required for LPS-induced cell swelling, reactive oxygen species (ROS) production and TNF-? release. The present study explored, whether rapamycin influences NHE activity and/or ROS formation in DCs. Mouse DCs were treated with LPS in the absence and presence of rapamycin (100 nM). ROS production was determined from 2',7'-dichlorodihydrofluorescein diacetate (DCFDA) fluorescence, cytosolic pH (pH(i)) from 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein (BCECF) fluorescence, NHE activity from the Na(+)-dependent realkalinization following an ammonium pulse, cell volume from forward scatter in FACS analysis, and TNF-? production utilizing ELISA. In the absence of LPS, rapamycin did not significantly modify cytosolic pH, NHE activity or cell volume but significantly decreased ROS formation. LPS stimulated NHE activity, enhanced forward scatter, increased ROS formation, and triggered TNF-? release, effects all blunted in the presence of rapamycin. NADPH oxidase inhibitor Vas-2870 (10 ?M) mimicked the effect of rapamycin on LPS induced stimulation of NHE activity and TNF-? release. The effect of rapamycin on TNF-? release was also mimicked by the antioxidant ROS scavenger Tempol (30 ?M) and partially reversed by additional application of tert-butylhydroperoxide (10 ?M). In conclusion, in DCs rapamycin disrupts LPS induced ROS formation with subsequent inhibition of NHE activity, cell swelling and TNF-? release. PMID:22508061

Rotte, Anand; Pasham, Venkanna; Bhandaru, Madhuri; Bobbala, Diwakar; Zelenak, Christine; Lang, Florian

2012-01-01

250

Arctigenin, a dietary phytoestrogen, induces apoptosis of estrogen receptor-negative breast cancer cells through the ROS/p38 MAPK pathway and epigenetic regulation.  

Science.gov (United States)

This study investigates the anticancer effect of arctigenin (ATG), a natural lignan product of Arctium lappa L., in human breast cancer MDA-MB-231 cells. Results indicate that ATG inhibits MDA-MB-231 cell growth by inducing apoptosis in vitro and in vivo. ATG triggers the mitochondrial caspase-independent pathways, as indicated by changes in Bax/Bcl-2 ratio, resulting in AIF and EndoG nuclear translocation. ATG increased cellular reactive oxygen species (ROS) production by increasing p22(phox)/NADPH oxidase 1 interaction and decreasing glutathione level. ATG clearly increases the activation of p38 MAPK, but not JNK and ERK1/2. Antioxidant EUK-8, a synthetic catalytic superoxide and hydrogen peroxide scavenger, significantly decreases ATG-mediated p38 activation and apoptosis. Blocking p38 with a specific inhibitor suppresses ATG-mediated Bcl-2 downregulation and apoptosis. Moreover, ATG activates ATF-2, a transcription factor activated by p38, and then upregulates histone H3K9 trimethylation in the Bcl-2 gene promoter region, resulting in Bcl-2 downregulation. Taken together, the results demonstrate that ATG induces apoptosis of MDA-MB-231 cells via the ROS/p38 MAPK pathway and epigenetic regulation of Bcl-2 by upregulation of histone H3K9 trimethylation. PMID:24140706

Hsieh, Chia-Jung; Kuo, Po-Lin; Hsu, Ying-Chan; Huang, Ya-Fang; Tsai, Eing-Mei; Hsu, Ya-Ling

2014-02-01

251

Hepatitis C virus proteins activate NRF2/ARE pathway by distinct ROS-dependent and independent mechanisms in HUH7 cells.  

Science.gov (United States)

Hepatitis C virus (HCV) is a highly pathogenic human virus associated with liver fibrosis, steatosis, and cancer. In infected cells HCV induces oxidative stress. Here, we show that HCV proteins core, E1, E2, NS4B, and NS5A activate antioxidant defense Nrf2/ARE pathway via several independent mechanisms. This was demonstrated by the analysis of transient co-expression in Huh7 cells of HCV proteins and luciferase reporters. Expression, controlled by the promoters of stress-response genes or their minimal Nrf2-responsive elements, was studied using luminescence assay, RT-qPCR and/or Western-blot analysis. All five proteins induced Nrf2 activation by protein kinase C in response to accumulation of reactive oxygen species (ROS). In addition, expression of core, E1, E2, NS4B, and NS5A proteins resulted in the activation of Nrf2 in a ROS-independent manner. The effect of core and NS5A was mediated through casein kinase 2 and phosphoinositide-3 kinase, whereas those of NS4B, E1, and E2, were not mediated by either PKC, CK2, PI3K, p38, or ERK. Altogether, on the earliest stage of expression HCV proteins induced a strong up-regulation of the antioxidant defense system. These events may underlie the harmful effects of HCV-induced oxidative stress during acute stage of hepatitis C. PMID:21931870

Ivanov, Alexander V; Smirnova, Olga A; Ivanova, Olga N; Masalova, Olga V; Kochetkov, Sergey N; Isaguliants, Maria G

2011-01-01

252

Agastache rugosa leaf extract inhibits the iNOS expression in ROS 17/2.8 cells activated with TNF-alpha and IL-1beta.  

Science.gov (United States)

It has been suggested that nitric oxide (NO) derived from inducible nitric oxide synthase (iNOS) may act as a mediator of cytokine-induced effects on bone turn-over. NO is also recognized as an important factor in bone remodeling, i.e., participating in osteoblast apoptosis in an arthritic joint. The components of Agastache rugosa are known to have many pharmacological activities. In the present study, we investigated the effects of Agastache rugosa leaf extract (ELAR) on NO production and the iNOS expression in ROS 17/2.8 cells activated by a mixture of inflammatory cytokines including TNF-alpha and IL-1beta. A preincubation with ELAR significantly and concentration-dependently reduced the expression of iNOS protein in ROS 17/2.8 cells activated with the cytokine mixture. Consequently, the NO production was also significantly reduced by ELAR with an IC50 of 0.75 mg/mL. The inhibitory mechanism of iNOS induction by ELAR prevented the activation and translocation of NF-kappaB (p65) to the nucleus from the cytosol fraction. Furthermore, ELAR concentration-dependently reduced the cellular toxicity induced by sodium nitroprusside, an NO-donor. These results suggest that ELAR may be beneficial in NO-mediated inflammatory conditions such as osteoporosis. PMID:15832818

Oh, Hwa Min; Kang, Young Jin; Kim, Sun Hee; Lee, Young Soo; Park, Min Kyu; Heo, Ja Myung; Sun, Jin ji; Kim, Hyo Jung; Kang, Eun Sil; Kim, Hye Jung; Seo, Han Geuk; Lee, Jae Heun; Yun-Choi, Hye Sook; Chang, Ki Churl

2005-03-01

253

A systems biology perspective on Nrf2-mediated antioxidant response  

International Nuclear Information System (INIS)

Cells in vivo are constantly exposed to reactive oxygen species (ROS) generated endogenously and exogenously. To defend against the deleterious consequences of ROS, cells contain multiple antioxidant enzymes expressed in various cellular compartments to scavenge these toxic species. Under oxidative stresses, these antioxidant enzymes are upregulated to restore redox homeostasis. Such an adaptive response results from the activation of a redox-sensitive gene regulatory network mediated by nuclear factor E2-related factor 2. To more completely understand how the redox control system is designed by nature to meet homeostatic goals, we have examined the network from a systems perspective using engineering approaches. As with man-made control devices, the redox control system can be decomposed into distinct functional modules, including transducer, controller, actuator, and plant. Cells achieve specific performance objectives by utilizing nested feedback loops, feedforward control, and ultrasensitive signaling motifs, etc. Given that endogenously generated ROS are also used as signaling molecules, our analysis suggests a novel mode of action to explain oxidative stress-induced pathological conditions and diseases. Specifically, by adaptively upregulating antioxidant enzymes, oxidative stress may inadvertently attenuate ROS signals that mediate physiological processes, resulting in aberrations of cellular functions and adverse consequences. Lastly, by simultaneously considering the two competing cellular tasks-adaptive antioxidant defense and ROS signaling-we re-examine the premise that dietary antioxidant supplements is generally beneficial to human health. Our analysis highlights some possible adverse effects of these widely consumed antioxidants.

2010-04-01

254

Synergistic Apoptosis of CML Cells by Buthionine Sulfoximine and Hydroxychavicol Correlates with Activation of AIF and GSH-ROS-JNK-ERK-iNOS Pathway  

Science.gov (United States)

Background Hydroxychavicol (HCH), a constituent of Piper betle leaf has been reported to exert anti-leukemic activity through induction of reactive oxygen species (ROS). The aim of the study is to optimize the oxidative stress –induced chronic myeloid leukemic (CML) cell death by combining glutathione synthesis inhibitor, buthionine sulfoximine (BSO) with HCH and studying the underlying mechanism. Materials and Methods Anti-proliferative activity of BSO and HCH alone or in combination against a number of leukemic (K562, KCL22, KU812, U937, Molt4), non-leukemic (A549, MIA-PaCa2, PC-3, HepG2) cancer cell lines and normal cell lines (NIH3T3, Vero) was measured by MTT assay. Apoptotic activity in CML cell line K562 was detected by flow cytometry (FCM) after staining with annexinV-FITC/propidium iodide (PI), detection of reduced mitochondrial membrane potential after staining with JC-1, cleavage of caspase- 3 and poly (ADP)-ribose polymerase proteins by western blot analysis and translocation of apoptosis inducing factor (AIF) by confocal microscopy. Intracellular reduced glutathione (GSH) was measured by colorimetric assay using GSH assay kit. 2?,7?-dichlorodihydrofluorescein diacetate (DCF-DA) and 4-amino-5-methylamino-2?,7?-difluorofluorescein (DAF-FM) were used as probes to measure intracellular increase in ROS and nitric oxide (NO) levels respectively. Multiple techniques like siRNA transfection and pharmacological inhibition were used to understand the mechanisms of action. Results Non-apoptotic concentrations of BSO significantly potentiated HCH-induced apoptosis in K562 cells. BSO potentiated apoptosis-inducing activity of HCH in CML cells by caspase-dependent as well as caspase-independent but apoptosis inducing factor (AIF)-dependent manner. Enhanced depletion of intracellular GSH induced by combined treatment correlated with induction of ROS. Activation of ROS- dependent JNK played a crucial role in ERK1/2 activation which subsequently induced the expression of inducible nitric oxide synthase (iNOS). iNOS- mediated production of NO was identified as an effector molecule causing apoptosis of CML cells. Conclusion/Significance BSO synergizes with HCH in inducing apoptosis of CML cells through the GSH-ROS-JNK-ERK-iNOS pathway.

Chowdhury, Avik Acharya; Chaudhuri, Jaydeep; Biswas, Nabendu; Manna, Anirban; Chatterjee, Saurav; Mahato, Sanjit K.; Chaudhuri, Utpal; Jaisankar, Parasuraman; Bandyopadhyay, Santu

2013-01-01

255

Thymoquinone induces apoptosis in malignant T-cells via generation of ROS.  

Science.gov (United States)

We show that HTLV-1 negative leukemia cells are more sensitive to TQ due to higher levels of drug-induced reactive oxygen species (ROS). PreG1 population in HTLV-1 negative Jurkat and CEM was higher than HTLV-1 transformed HuT-102 and MT-2 cells. Peripheral blood mononuclear cells were more resistant. Hoechst staining indicated more features of apoptosis, namely nuclear blebs and shrunken nuclei in HuT-102 than Jurkat. A greater depletion of the antioxidant enzyme glutathione occurred in Jurkat, which consequently led to an increase in ROS, loss of mitochondrial membrane potential, cytochrome c release, activation of caspases 3 and 9, and cleavage of PARP. Treatment with z-VAD-fmk partially reversed TQ-induced apoptosis, suggesting a caspase-dependent mechanism. N-acetyl cysteine prevented apoptosis providing evidence that cell death is ROS-dependent. Catalase prevented apoptosis to a lesser extent than NAC. In summary, TQ induces apoptosis in adult T cell leukemia/lymphoma by decreasing glutathione and increasing ROS, and levels of ROS underlie the differential cellular response to TQ. Our data suggest a potential therapeutic role for TQ in sensitizing HTLV-I-negative T-cell lymphomas. PMID:23277025

Dergarabetian, Eileen Manasse; Ghattass, Khaled Imad; El-Sitt, Sally Boulos; Al-Mismar, Rasha Mahmoud; El-Baba, Chirine Omar; Itani, Wafica Sami; Melhem, Nada Mohamad; El-Hajj, Hiba Ahmad; Bazarbachi, Ali Abdul Hamid; Schneider-Stock, Regine; Gali-Muhtasib, Hala Uthman

2013-01-01

256

Lovastatin inhibits human B lymphoma cell proliferation by reducing intracellular ROS and TRPC6 expression.  

Science.gov (United States)

Clinical evidence suggests that statins reduce cancer incidence and mortality. However, there is lack of in vitro data to show the mechanism by which statins can reduce the malignancies of cancer cells. We used a human B lymphoma Daudi cells as a model and found that lovastatin inhibited, whereas exogenous cholesterol (Cho) stimulated, proliferation cell cycle progression in control Daudi cells, but not in the cells when transient receptor potential canonical 6 (TRPC6) channel was knocked down. Lovastatin decreased, whereas Cho increased, the levels of intracellular reactive oxygen species (ROS) respectively by decreasing or increasing the expression of p47-phox and gp91-phox (NOX2). Reducing intracellular ROS with either a mimetic superoxide dismutase (TEMPOL) or an NADPH oxidase inhibitor (apocynin) inhibited cell proliferation, particularly in Cho-treated cells. The effects of TEMPOL or apocynin were mimicked by inhibition of TRPC6 with SKF-96365. Lovastatin decreased TRPC6 expression and activity via a Cho-dependent mechanism, whereas Cho increased TRPC6 expression and activity via an ROS-dependent mechanism. Consistent with the fact that TRPC6 is a Ca(2+)-permeable channel, lovastatin decreased, but Cho increased, intracellular Ca(2+) also via ROS. These data suggest that lovastatin inhibits malignant B cell proliferation by reducing membrane Cho, intracellular ROS, TRPC6 expression and activity, and intracellular Ca(2+). PMID:24518247

Song, Xiang; Liu, Bing-Chen; Lu, Xiao-Yu; Yang, Li-Li; Zhai, Yu-Jia; Eaton, Amity F; Thai, Tiffany L; Eaton, Douglas C; Ma, He-Ping; Shen, Bao-Zhong

2014-05-01

257

Luteolin from Purple Perilla mitigates ROS insult particularly in primary neurons.  

Science.gov (United States)

Increased attention has been paid to the role of oxidant/antioxidant imbalance in neurodegenerative process and pharmaceutical neuroprotective interventions. Food-derived compound luteolin possesses multitarget actions including reactive oxygen species (ROS)-scavenging activity in cultured human endothelial cells or permanent immature rat oligodendrocytes. This study aims to elucidate whether luteolin has a neuroprotective tendency toward ROS-insulted neural cells. The present results showed that luteolin, isolated from the ripe seed of Perilla frutescens (L.) Britt., markedly reversed hydrogen peroxide-induced cytotoxicity in primary culture cortical neurons but not in cultured human neuroblastoma cells. Upon the ROS-insulted primary neurons, luteolin concentration-dependently enhanced neuronal cell survival with efficacy higher than and potency similar to vitamin E. Additionally, luteolin significantly attenuated the increase in ROS production and prevented the decreases in activities of mitochondria, catalase, and glutathione in ROS-insulted primary neurons. Thus, luteolin functions by neuroprotection possibly through a rebalancing of pro-oxidant-antioxidant status. This agent points to possible interventions for preventing neurodegenerative diseases such as cerebral ischemia, Parkinson's disease, and Alzheimer's disease, as well as for improving brain aging. PMID:20382451

Zhao, Gang; Yao-Yue, Chen; Qin, Guo-Wei; Guo, Li-He

2012-01-01

258

Phorbol ester and light-induced endogenous phosphorylation of rat retinal rod outer segment (ROS) proteins  

International Nuclear Information System (INIS)

The authors have previously described the presence of a C-kinase in bovine ROS and its in vitro activation by light in crude rat ROS. In this study, they have labelled the retinas with 33Pi by intravitreal injection and compared the phosphorylation pattern of ROS proteins induced by light and activators of the C-kinase phosphorylation system. Except for light treatment, all procedures were carried out in complete darkness using an infrared image converter. Incubation of 33P-labelled retinas in light for 5 minutes resulted in the phosphorylation of rhodopsin, 80,65,47,44, and 15kd proteins of crude ROS. Incubation of 33P-labelled retinas with 5?M 12-0-tetradecanoylphorbol-13-acetate (TPA) resulted in the phosphorylation of 80,65,47,44,33, and 15 kd proteins of crude ROS. The complete darkness control did not exhibit any phosphorylation or proteins whereas the red light control exhibited variable low phosphorylation of 80,47,44, and 15kd proteins. 1-oleoyl-2-acetyl-glycerol (OAG) at 500?g/ml caused the phosphorylation of the same proteins as observed with TPA. TPA (0.5-500?M) and OAG (150-500?g/ml) did not induce rhodopsin phosphorylation. Since light, TPA and OAG exhibit similarities in the phosphorylation patterns of proteins (except for rhodopsin), these results suggest at least a partial linkage of light and C-kinase effects in vivo

1986-05-01

259

Adhesive protein-free synthetic hydrogels for retinal pigment epithelium cell culture with low ROS level.  

Science.gov (United States)

Engineering of human retinal pigment epithelium (RPE) cell monolayer with low level of reactive oxygen species (ROS) is important for regenerative RPE-based therapies. However, it is still challenging to culture RPE monolayer with low ROS level on soft substrates in vitro. To address this, we developed cytocompatible hydrogels to culture human RPE cell monolayer for future use in regenerative RPE-based therapies. The cell adhesion, proliferation, monolayer formation, morphology, survival, and ROS level of human ARPE-19 cells cultured on the surfaces of negatively charged poly (2-acrylamido-2-methyl propane sulfonic sodium) (PNaAMPS) and neutral poly(N,N-dimethylacrylamide) (PDMAAm) hydrogels with different stiffness were investigated. The importance of hydrogel stiffness on the cell function was firstly highlighted on the base of determined optimal Young's modulus for cultivation of RPE cell monolayer with relatively low ROS level. The construction of RPE cell monolayer with low ROS level on the PNaAMPS hydrogel may hold great potential as promising candidates for transplantation of RPE cell monolayer-hydrogel construct into the subretinal space to repair retinal functions. PMID:23913900

Chen, Yong Mei; Liu, Zhen Qi; Feng, Zhi Hui; Xu, Feng; Liu, Jian Kang

2014-07-01

260

Generation of reactive oxygen species mediated by humic-like substances in atmospheric aerosols.  

Science.gov (United States)

Particulate matter (PM)-mediated reactive oxygen species (ROS) generation has been implicated in health effects posed by PM. Humic-like substances (HULIS) are an unresolved mixture of water-extracted organic compounds from atmospheric aerosol particles or isolated from fog/cloudwater samples. In this study, we use a cell-free dithiothreitol (DTT) assay to measure ROS production mediated by HULIS. The HULIS samples are isolated from aerosols collected at a rural location and a suburban location in the Pearl River Delta, China. In our experiments, ROS activities by residue metal ions in the HULIS fraction are suppressed by including a strong chelating agent in the DTT assay. Under conditions of DTT consumption not exceeding 90%, the HULIS-catalyzed oxidation of DTT follows the zero-order kinetics with respect to DTT concentration, and the rate of DTT oxidation is proportional to the dose of HULIS. The ROS activity of the aerosol HULIS, on a per unit mass basis is 2% of the ROS activity by a reference quinone compound, 1,4-naphthoquinone and exceeds that of two aquatic fulvic acids. The HULIS fraction in the ambient samples tested exhibits comparable ROS activities to the organic solvent extractable fraction, which would contain compounds such as quinones, a known organic compound class capable of catalyzing generation of ROS in cells. HULIS was found to be the major redox active constituent of the water-extractable organic fraction in PM. It is plausible that HULIS contains reversible redox sites, thereby serving as electron carriers to catalyze the formation of ROS. Our work suggests that HULIS could be an active PM component in generating ROS and further work is warranted to characterize its redox properties. PMID:22044074

Lin, Peng; Yu, Jian Zhen

2011-12-15

 
 
 
 
261

??ALA-PDT?HL60????????? ROS Detection in HL60 Based on ALA-PDT  

Directory of Open Access Journals (Sweden)

Full Text Available ????????(photodynamic therapy, PDT?????????????????????PDT????????????????????PDT?????????????????????????????????ALA-PDT?HL60???????????????????ALA???10 mM/L??????4 h??????60 min???????????????????????HL60?????????PDT???93.2%?With the development of the basic research of photodynamic therapy (PDT and a wide range of potential clinical applications have be carried out. The monitoring of reactive oxygen species (ROS which produced in PDT has become a hot issue of PDT research in recent years. In the paper, the status of ROS in HL60 cells were investigated by fluorescence spectra acquired during PDT. The results showed that the largest number of ROS in PDT was achieved at the optimized conditions(the cells incubation time is 4 hours, the added concentration of ALA is 10 mM/L, in which up to 93.2% PDT efficiency for the HL60 Cells can be obtained within 60 minutes.

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2011-12-01

262

Elucidating hormonal/ROS networks during seed germination: insights and perspectives  

DEFF Research Database (Denmark)

While authors have traditionally emphasized the deleterious effects of reactive oxygen species (ROS) on seed biology, their role as signaling molecules during seed dormancy alleviation and germination is now the focus of many studies around the world. Over the last few years, studies using â??-omicsâ?ť technologies together with physiological and biochemical approaches have revealed that seed germination is a very complex process that depends on multiple biochemical and molecular variables. The pivotal role of phytohormones in promoting germination now appears to be interdependent with ROS metabolism, involving mitogen-activated protein kinase cascade activation, gene expression and post-translational protein modifications. This review is, thus, an attempt to summarize the new discoveries involving ROS and seed germination. The study of these interactions may supply markers of seed quality that might eventually be used in breeding programs to improve crop yields.

Diaz-Vivancos, Pedro; Barba Espin, Gregorio

2013-01-01

263

Antioxidant pathways are up-regulated during biological nitrogen fixation to prevent ROS-induced nitrogenase inhibition in Gluconacetobacter diazotrophicus  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Gluconacetobacter diazotrophicus, an endophyte isolated from sugarcane, is a strict aerobe that fixates N2. This process is catalyzed by nitrogenase and requires copious amounts of ATP. Nitrogenase activity is extremely sensitive to inhibition by oxygen and reactive oxygen species (ROS). However, the elevated oxidative metabolic rates required to sustain biological nitrogen fixation (BNF) may favor an increased production of ROS. Here, we explored this paradox and observed that ROS levels are...

Alque?res, Sylvia M. C.; Oliveira, Jose Henrique M.; Nogueira, Eduardo M.; Guedes, Helma V.; Oliveira, Pedro L.; Ca?mara, Fernando; Baldani, Jose I.; Martins, Orlando B.

2010-01-01

264

Induction of apoptosis by plumbagin through reactive oxygen species-mediated inhibition of topoisomerase II  

International Nuclear Information System (INIS)

Reactive oxygen species (ROS) have been recognized as key molecules, which can selectively modify proteins and therefore regulate cellular signalling including apoptosis. Plumbagin, a naphthoquinone exhibiting antitumor activity, is known to generate ROS and has been found to inhibit the activity of topoisomerase II (Topo II) through the stabilization of the Topo II-DNA cleavable complex. The objective of this research was to clarify the role of ROS and Topo II inhibition in the induction of apoptosis mediated by plumbagin. As determined by the comet assay, plumbagin induced DNA cleavage in HL-60 cells, whereas in a cell line with reduced Topo II activity-HL-60/MX2, the level of DNA damage was significantly decreased. The onset of DNA strand break formation in HL-60 cells was delayed in comparison with the generation of intracellular ROS. In HL-60/MX2 cells, ROS were generated at a similar rate, whereas a significant reduction in the level of DNA damage was detected. The pretreatment of cells with N-acetylcysteine (NAC) attenuated plumbagin-induced DNA damage, pointing out to the involvement of ROS generation in cleavable complex formation. These results suggest that plumbagin-induced ROS does not directly damage DNA but requires the involvement of Topo II. Furthermore, experiments carried out using light spectroscopy indicated no direct interactions between plumbagin and DNA. The induction of apoptosis was significantly delayed in HL-60/MX2 cells indicating the involvement of Topo II inhibition in plumbagin-mediated apoptosis. Thus, these findings strongly suggest ROS-mediated inhibition of Topo II as an important mechanism contributing to the apoptosis-inducing properties of plumbagin

2007-09-15

265

Reactive oxygen species (ROS) are involved in enhancement of NMDA-receptor phosphorylation in animal models of pain  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Recent studies indicate that reactive oxygen species (ROS) play an important role in neuropathic pain, predominantly through spinal mechanisms. Since the data suggest that ROS are involved in central sensitization, the present study examines the levels of activated N-methyl-D-aspartate (NMDA) receptors in the dorsal horn before and after removal of ROS with a ROS scavenger, phenyl-N-t-butyl nitrone (PBN), in animal models of pain. Tight ligation of the L5 spinal nerve was used for the neuropa...

Gao, Xiu; Kim, Hee Kee; Chung, Jin Mo; Chung, Kyungsoon

2007-01-01

266

Trypanosoma cruzi infection disturbs mitochondrial membrane potential and ROS production rate in cardiomyocytes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this study, we investigated the role of Trypanosoma cruzi invasion and inflammatory processes in reactive oxygen species (ROS) production in mouse atrial cardiomyocyte line (HL-1) and primary adult rat ventricular cardiomyocytes. Cardiomyocytes were incubated with T. cruzi (Tc) trypomastigotes, Tc lysate (TcTL) or Tc secreted proteins (TcSP) for 0-72 h, and ROS measured by amplex red assay. Cardiomyocytes infected by T. cruzi (but not those incubated with TcTL or TcSP) exhibited a linear i...

Gupta, Shivali; Bhatia, Vandanajay; Wen, Jian-jun; Wu, Yewen; Huang, Ming-he; Garg, Nisha Jain

2009-01-01

267

Proteomic analysis of mitochondria from senescent Podospora anserina casts new light on ROS dependent aging mechanisms.  

Science.gov (United States)

The mitochondrial free radical theory of aging (MFRTA) states that reactive oxygen species (ROS) generated at the respiratory electron transport chain are active in causing age-related damage of biomolecules like lipids, nucleic acids and proteins. Accumulation of this kind of damage results in functional impairments, aging and death of biological systems. Here we report data of an analysis to monitor the age-related quantitative protein composition of the mitochondria of the fungal aging model Podospora anserina. The impact of senescence on mitochondrial protein composition was analyzed by LC-MS. In an untargeted proteomic approach, we identified 795 proteins in samples from juvenile and senescent wild-type cultures and obtained quantitative information for 226 of these proteins by spectral counting. Despite the broad coverage of the proteome, no substantial changes in known age-related pathways could be observed. For a more detailed analysis, a targeted proteome analysis was applied focusing on 15 proteins from respiratory, ROS-scavenging and quality control pathways. Analyzing six distinct age-stages from juvenile to senescent P. anserina cultures revealed low, but statistically significant changes for the mitochondrial respiratory complexes. A P. anserina PaSod3 over-expression mutant with a phenotype of mitochondrial ROS over-production was used for biological evaluation of changes observed during aging. LC-MS analysis of the mutant revealed severe changes to the mitochondrial proteome--substantially larger than observed during senescence. Interestingly the amount of ATP synthase subunit g, involved in cristae formation is significantly decreased in the mutant implicating ROS-induced impairments in ATP synthase dimer and cristae formation. The difference between protein-profiles of aging wild type and ROS stressed mutant suggests that oxidative stress within the mitochondria is not the dominating mechanism for the aging process in P. anserina. Collectively, while our data do not exclude an effect of ROS on specific proteins and in signaling and control of pathways which are governing aging of P. anserina, it contradicts increasing ROS as a cause of a gross general and non-selective accumulation of damaged proteins during senescence. Instead, ROS may be effective by controlling specific regulators of mitochondrial function. PMID:24556281

Plohnke, Nicole; Hamann, Andrea; Poetsch, Ansgar; Osiewacz, Heinz D; Rögner, Matthias; Rexroth, Sascha

2014-08-01

268

ROS, Notch, and Wnt Signaling Pathways: Crosstalk between Three Major Regulators of Cardiovascular Biology  

Science.gov (United States)

Reactive oxygen species (ROS), traditionally viewed as toxic by-products that cause damage to biomolecules, now are clearly recognized as key modulators in a variety of biological processes and pathological states. The development and regulation of the cardiovascular system require orchestrated activities; Notch and Wnt/?-catenin signaling pathways are implicated in many aspects of them, including cardiomyocytes and smooth muscle cells survival, angiogenesis, progenitor cells recruitment and differentiation, arteriovenous specification, vascular cell migration, and cardiac remodelling. Several novel findings regarding the role of ROS in Notch and Wnt/?-catenin modulation prompted us to review their emerging function in the cardiovascular system during embryogenesis and postnatally.

Caliceti, C.; Nigro, P.; Rizzo, P.; Ferrari, R.

2014-01-01

269

As a novel p53 direct target, bidirectional gene HspB2/?B-crystallin regulates the ROS level and Warburg effect.  

Science.gov (United States)

Many mammalian genes are composed of bidirectional gene pairs with the two genes separated by less than 1.0kb. The transcriptional regulation and function of these bidirectional genes remain largely unclear. Here, we report that bidirectional gene pair HspB2/?B-crystallin, both of which are members of the small heat shock protein gene family, is a novel direct target gene of p53. Two potential binding sites of p53 are present in the intergenic region of HspB2/?B-crystallin. p53 up-regulated the bidirectional promoter activities of HspB2/?B-crystallin. Actinomycin D (ActD), an activator of p53, induces the promoter and protein activities of HspB2/?B-crystallin. p53 binds to two p53 binding sites in the intergenic region of HspB2/?B-crystallin in vitro and in vivo. Moreover, the products of bidirectional gene pair HspB2/?B-crystallin regulate glucose metabolism, intracellular reactive oxygen species (ROS) level and the Warburg effect by affecting metabolic genes, including the synthesis of cytochrome c oxidase 2 (SCO2), hexokinase II (HK2), and TP53-induced glycolysis and apoptosis regulator (TIGAR). The ROS level and the Warburg effect are affected after the depletion of p53, HspB2 and ?B-crystallin respectively. Finally, we show that both HspB2 and ?B-crystallin are linked with human renal carcinogenesis. These findings provide novel insights into the role of p53 as a regulator of bidirectional gene pair HspB2/?B-crystallin-mediated ROS and the Warburg effect. PMID:24859470

Liu, Shuang; Yan, Bin; Lai, Weiwei; Chen, Ling; Xiao, Desheng; Xi, Sichuan; Jiang, Yiqun; Dong, Xin; An, Jing; Chen, Xiang; Cao, Ya; Tao, Yongguang

2014-07-01

270

Induction and determination of ROS and their effect on peroxisome dynamics  

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Peroxissomas săo organelos celulares de membrana simples, os quais tęm importantes funçőes metabólicas, como por exemplo metabolismo de lípidos e ROS, sendo assim indispensáveis para a saúde e desenvolvimento humano. Os peroxissomas săo organelos altamente flexíveis e dinâmicos que rapidamente se agregam, multiplicam e degradam em resposta a necessidades metabólicas. Em cultura celular, o stress oxidativo e outros estímulos externos (ex. factores de crescimento,...

Pinho, So?nia Andreia Almeida

2010-01-01

271

Ros production by endogenously generated Protoporphyrin IX in murine leukemia cells.  

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Endogenous production of Protoporphyrin IX (PpIX) is successfully exploited for photodynamic therapy (PDT) on malignant cells, following 5-aminolevulinic acid (ALA) administration and light irradiation. This treatment kills cancer cells by damaging organelles and impairing metabolic pathways via cellular reactive oxygen species (ROS) generation. We studied the efficiency of PpIX synthetized from ALA on ROS generation, in the Vincristine resistant (LBR-V160), Doxorubicin resistant (LBR-D160) and sensitive (LBR-) murine leukemia cell lines. Cells were incubated 4 hr with 1 mM ALA and then irradiated during different times with fluorescent light. One hour later, production of ROS was analyzed by flow cytometry using different fluorescent probes: Hydroethidine (HE) for superoxide anion, 2',7' Dichlorodihydrofluorescein diacetate (DCFH-DA) for hydrogen peroxide; mitochondrial damage was examined with 3,3' Dihexyloxacarbocyanine iodide (DiOC6). We found that superoxide anion production in the three cell lines increased with irradiation time whereas no peroxide hydrogen was detected. Mitochondrial damage also increased in an irradiation time dependent manner, being higher in the Vincristine resistant line. Previous studies have demonstrated that apoptotic cell death increased with irradiation time, which is consistent with these results, indicating that ROS are critical in ALA-PDT efficiency to kill malignant cells. PMID:19656446

Diez, B; Cordo Russo, R; Teijo, M J; Hajos, S; Batlle, A; Fukuda, H

2009-01-01

272

Heat stress induces ROS production and histone phosphorylation in celomocytes of Eisenia hortensis  

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Full Text Available The effect of heat stress on celomocytes (leukocytes from Eisenia hortensis was investigated by measuring the production of reactive oxygen species (ROS. After culturing celomocytes at temperatures ranging from 4 °C (control to 44 °C for 3-16 h, ROS levels were measured using a flow cytometric method employing dihydrorhodamine 123 (DHR123 for ROS detection and 7-aminoactinomycin D (7-AAD as a viability stain. Reproducibly we observed significant (p < 0.05 increases in ROS production and decreases in cell viability at temperatures of 28 °C and above. We then examined the effect of heat stress on histone phosphorylation employing antibodies specific for ?H2AX as an indicator of histone modification. Celomocytes were incubated at temperatures ranging between 20 °C to 35 °C for 16 h and antibodies specific for phosphorylated serines in H2AX histones were employed through flow cytometric analysis. Comparing controls to heat-stressed samples using three separate assays reproducibly confirmed significant H2AX phosphorylation (p < 0.05. Collectively, these results emphasize the importance of selecting appropriate temperatures for rearing invertebrates in laboratory-based habitats and for culturing invertebrate cells when conducting in vitro assays in order to minimize oxidative stress. The possible cellular effects of heat stress in soil ecosystems associated with global warming events is also considered.

RA Tumminello

2013-07-01

273

Resveratrol inhibits foam cell formation via NADPH oxidase 1-mediated reactive oxygen species and monocyte chemotactic protein-1  

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Resveratrol is a polyphenolic compound in red wine that has anti-oxidant and cardioprotective effects in animal models. Reactive oxygen species (ROS) and monocyte chemotactic protein-1 (MCP-1) play key roles in foam cell formation and atherosclerosis. We studied LPS-mediated foam cell formation and the effect of resveratrol. Resveratrol pretreatment strongly suppressed LPS-induced foam cell formation. To determine if resveratrol affected the expression of genes that control ROS generation in ...

Park, Dae-weon; Baek, Kheewoong; Kim, Jae-ryong; Lee, Jae-jin; Ryu, Sang-ho; Chin, Byung-rho; Baek, Suk-hwan

2009-01-01

274

Cellular localization of ROS and NO in olive reproductive tissues during flower development  

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Full Text Available Abstract Background Recent studies have shown that reactive oxygen species (ROS and nitric oxide (NO are involved in the signalling processes taking place during the interactions pollen-pistil in several plants. The olive tree (Olea europaea L. is an important crop in Mediterranean countries. It is a dicotyledonous species, with a certain level of self-incompatibility, fertilisation preferentially allogamous, and with an incompatibility system of the gametophytic type not well determined yet. The purpose of the present study was to determine whether relevant ROS and NO are present in the stigmatic surface and other reproductive tissues in the olive over different key developmental stages of the reproductive process. This is a first approach to find out the putative function of these signalling molecules in the regulation of the interaction pollen-stigma. Results The presence of ROS and NO was analyzed in the olive floral organs throughout five developmental stages by using histochemical analysis at light microscopy, as well as different fluorochromes, ROS and NO scavengers and a NO donor by confocal laser scanning microscopy. The "green bud" stage and the period including the end of the "recently opened flower" and the "dehiscent anther" stages displayed higher concentrations of the mentioned chemical species. The stigmatic surface (particularly the papillae and the stigma exudate, the anther tissues and the pollen grains and pollen tubes were the tissues accumulating most ROS and NO. The mature pollen grains emitted NO through the apertural regions and the pollen tubes. In contrast, none of these species were detected in the style or the ovary. Conclusion The results obtained clearly demonstrate that both ROS and NO are produced in the olive reproductive organs in a stage- and tissue- specific manner. The biological significance of the presence of these products may differ between early flowering stages (defence functions and stages where there is an intense interaction between pollen and pistil which may determine the presence of a receptive phase in the stigma. The study confirms the enhanced production of NO by pollen grains and tubes during the receptive phase, and the decrease in the presence of ROS when NO is actively produced.

Alché Juan

2010-02-01

275

Thrombin, a mediator of cerebrovascular inflammation in AD and hypoxia  

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Full Text Available Considerable evidence implicates hypoxia and vascular inflammation in Alzheimer’s disease (AD. Thrombin, a multifunctional inflammatory mediator, is demonstrable in the brains of AD patients both in the vessel walls and senile plaques. Hypoxia-inducible factor 1? (HIF-1?, a key regulator of the cellular response to hypoxia, is also upregulated in the vasculature of human AD brains. The objective of this study is to investigate inflammatory protein expression in the cerebrovasculature of transgenic AD mice and to explore the role of thrombin as a mediator of cerebrovascular inflammation and oxidative stress in AD and in hypoxia-induced changes in brain endothelial cells. Immunofluorescent analysis of the cerebrovasculature in AD mice demonstrates significant (p<0.01-0.001 increases in thrombin, HIF-1?, interleukin-6 (IL-6, monocyte chemoattractant protein-1 (MCP-1, matrix metalloproteinases (MMPs, and reactive oxygen species (ROS compared to controls. Administration of the thrombin inhibitor dabigatran (100 mg/kg to AD mice for 34 wks significantly decreases expression of inflammatory proteins and ROS. Exposure of cultured brain endothelial cells to hypoxia for 6 h causes an upregulation of thrombin, HIF-1?, MCP-1, IL-6 and MMP2 and ROS. Treatment of endothelial cells with the dabigatran (1 nM reduces ROS generation and inflammatory protein expression (p<0.01-0.001. The data demonstrate that inhibition of thrombin in culture blocks the increase in inflammatory protein expression and ROS generation evoked by hypoxia. Also, administration of dabigatran to transgenic AD mice diminishes expression of inflammatory proteins and ROS in the cerebromicrovasculature. Taken together, these results suggest that inhibiting thrombin generation could have therapeutic value in AD and other disorders where hypoxia, inflammation and oxidative stress are involved.

PaulaGrammas

2013-05-01

276

Antioxidant pathways are up-regulated during biological nitrogen fixation to prevent ROS-induced nitrogenase inhibition in Gluconacetobacter diazotrophicus  

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Gluconacetobacter diazotrophicus, an endophyte isolated from sugarcane, is a strict aerobe that fixates N2. This process is catalyzed by nitrogenase and requires copious amounts of ATP. Nitrogenase activity is extremely sensitive to inhibition by oxygen and reactive oxygen species (ROS). However, the elevated oxidative metabolic rates required to sustain biological nitrogen fixation (BNF) may favor an increased production of ROS. Here, we explored this paradox and observed that ROS levels are, in fact, decreased in nitrogen-fixing cells due to the up-regulation of transcript levels of six ROS-detoxifying genes. A cluster analyses based on common expression patterns revealed the existence of a stable cluster with 99.8% similarity made up of the genes encoding the ?-subunit of nitrogenase Mo–Fe protein (nifD), superoxide dismutase (sodA) and catalase type E (katE). Finally, nitrogenase activity was inhibited in a dose-dependent manner by paraquat, a redox cycler that increases cellular ROS levels. Our data revealed that ROS can strongly inhibit nitrogenase activity, and G. diazotrophicus alters its redox metabolism during BNF by increasing antioxidant transcript levels resulting in a lower ROS generation. We suggest that careful controlled ROS production during this critical phase is an adaptive mechanism to allow nitrogen fixation.

Oliveira, Jose Henrique M.; Nogueira, Eduardo M.; Guedes, Helma V.; Oliveira, Pedro L.; Camara, Fernando; Baldani, Jose I.; Martins, Orlando B.

2010-01-01

277

TGF-{beta}1 increases invasiveness of SW1990 cells through Rac1/ROS/NF-{kappa}B/IL-6/MMP-2  

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Research highlights: {yields} Rac1 mediates TGF-{beta}1-induced SW1990 invasion through MMP-2 secretion and activation. {yields} NADPH-generated ROS act downstream of Rac1 in TGF-{beta}1-challenged SW1990 cells. {yields} TGF-{beta}1-stimulated ROS activate NF-{kappa}B in SW1990 cells. {yields} NF{kappa}B-induced IL-6 release is required for secretion and activation of MMP-2 in SW1990 cells. -- Abstract: Human pancreatic cancer invasion and metastasis have been found to correlate with increased levels of active matrix metalloproteinase 2 (MMP-2). The multifunctional cytokine transforming growth factor beta 1 (TGF-{beta}1) has been shown to increase both secretion of MMP-2 and invasion by several pancreatic cancer cell types. In the present study, we investigated the signaling pathway involved in TGF-{beta}1-promoted MMP-2 secretion and invasion by human pancreatic cancer cells SW1990. Using specific inhibitors, we found that stimulation of these tumor cells with TGF-{beta}1 induced secretion and activation of the collagenase MMP-2, which was required for TGF-{beta}1-stimulated invasion. Our results also indicate that signaling events involved in TGF-{beta}1-enhanced SW1990 invasiveness comprehend activation of Rac1 followed by generation of reactive oxygen species through nicotinamide adenine dinucleotide phosphate-oxidase, activation of nuclear factor-kappa beta, release of interleukin-6, and secretion and activation of MMP-2.

Binker, Marcelo G. [Departments of Medicine and Physiology, University of Toronto, Toronto, Ontario, Canada M5S 1A8 (Canada); CBRHC Research Center, Buenos Aires (Argentina); Binker-Cosen, Andres A. [CBRHC Research Center, Buenos Aires (Argentina); Gaisano, Herbert Y. [Departments of Medicine and Physiology, University of Toronto, Toronto, Ontario, Canada M5S 1A8 (Canada); Cosen, Rodica H. de [CBRHC Research Center, Buenos Aires (Argentina); Cosen-Binker, Laura I., E-mail: laura.cosen.binker@utoronto.ca [Departments of Medicine and Physiology, University of Toronto, Toronto, Ontario, Canada M5S 1A8 (Canada); CBRHC Research Center, Buenos Aires (Argentina)

2011-02-04

278

Protection by tetrahydroxystilbene glucoside against cerebral ischemia: involvement of JNK, SIRT1, and NF-kappaB pathways and inhibition of intracellular ROS/RNS generation.  

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Many natural polyphenolic compounds have been shown to attenuate reactive oxygen/nitrogen species (ROS/RNS) formation and protect against ischemia/reperfusion injury both in vitro and in vivo. 2,3,5,4'-tetrahydroxystilbene-2-O-beta-D-glucoside (TSG), an active component of the rhizome extract from Polygonum multiflorum, exhibits antioxidative and anti-inflammatory effects. Here, we used an in vitro ischemic model of oxygen-glucose deprivation followed by reperfusion (OGD-R) and an in vivo ischemic model of middle cerebral artery occlusion (MCAO) to investigate the neuroprotective effects of TSG on ischemia/reperfusion brain injury and the related mechanisms. We demonstrated that OGD-R-induced neuronal injury, intracellular ROS generation, and mitochondrial membrane potential dissipation were reversed by TSG. The elevation of H2O2-induced [Ca2+]i was also attenuated by TSG. Inhibition of the c-Jun N-terminal kinase (JNK) and Bcl-2 family-related apoptotic signaling pathway was involved in the neuroprotection afforded by TSG. Meanwhile, TSG inhibited iNOS mRNA expression induced by OGD-R, which may be mediated by the activation of SIRT1 and inhibition of NF-kappaB activation. In vivo studies further demonstrated that TSG significantly reduced the brain infarct volume and the number of positive cells by TUNEL staining in the cerebral cortex compared to the MCAO group. Our study indicates that TSG protects against cerebral ischemia/reperfusion injury through multifunctional cytoprotective pathways. PMID:19272442

Wang, Ting; Gu, Jun; Wu, Peng-Fei; Wang, Fang; Xiong, Zhe; Yang, Yuan-Jian; Wu, Wen-Ning; Dong, Ling-Dan; Chen, Jian-Guo

2009-08-01

279

ROS and NF-?B are involved in upregulation of IL-8 in A549 cells exposed to multi-walled carbon nanotubes  

International Nuclear Information System (INIS)

Carbon nanotubes (CNTs) have potential applications in biosensors, tissue engineering, and biomedical devices because of their unique physico-chemical, electronic and mechanical properties. However, there is limited literature data available concerning the biological properties and toxicity of CNTs. This study aimed to assess the toxicity exhibited by multi-walled CNTs (MWCNTs) and to elucidate possible molecular mechanisms underlying the biological effects of MWCNTs in A549 cells. Exposing A549 cells to MWCNTs led to cell death, changes in cell size and complexity, reactive oxygen species (ROS) production, interleukin-8 (IL-8) gene expression and nuclear factor (NF)-?B activation. Treatment of A549 cells with antioxidants prior to adding MWCNTs decreased ROS production and abrogated expression of IL-8 mRNA. Pretreatment of A549 cells with NF-?B inhibitors suppressed MWCNTs-induced IL-8 mRNA expression. These results indicate that MWCNTs are able to induce expression of IL-8 in A549 cells, at least in part, mediated by oxidative stress and NF-?B activation.

2009-02-06

280

Agaricus blazei Extract Induces Apoptosis through ROS-Dependent JNK Activation Involving the Mitochondrial Pathway and Suppression of Constitutive NF-?B in THP-1 Cells.  

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Agaricus blazei is widely accepted as a traditional medicinal mushroom, and it has been known to exhibit immunostimulatory and anti-cancer activity. However, the apoptotic mechanism in cancer cells is poorly understood. In this study, we have investigated whether A. blazei extract (ABE) exerts antiproliferative and apoptotic effects in human leukemic THP-1 cells. We observed that ABE-induced apoptosis is associated with the mitochondrial pathway, which is mediated by reactive oxygen species (ROS) generation and prolonged c-Jun N-terminal kinase (JNK) activation. In addition, the ABE treatment resulted in the accumulation of cytochrome c in the cytoplasm, an increase in caspase activity, and an upregulation of Bax and Bad. With those results in mind, we found that ABE decreases constitutive NF-?B activation and NF-?B-regulated gene products such as IAP-1 and -2. We concluded that ABE induces apoptosis with ROS-dependent JNK activation and constitutive activated NF-?B inhibition in THP-1 cells. PMID:19861509

Kim, Mun-Ock; Moon, Dong-Oh; Jung, Jin Myung; Lee, Won Sup; Choi, Yung Hyun; Kim, Gi-Young

2011-01-01

 
 
 
 
281

The TrkAIII Oncoprotein Inhibits Mitochondrial Free Radical ROS-Induced Death of SH-SY5Y Neuroblastoma Cells by Augmenting SOD2 Expression and Activity at the Mitochondria, within the Context of a Tumour Stem Cell-like Phenotype  

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The developmental and stress-regulated alternative TrkAIII splice variant of the NGF receptor TrkA is expressed by advanced stage human neuroblastomas (NBs), correlates with worse outcome in high TrkA expressing unfavourable tumours and exhibits oncogenic activity in NB models. In the present study, we report that constitutive TrkAIII expression in human SH-SY5Y NB cells inhibits Rotenone, Paraquat and LY83583-induced mitochondrial free radical reactive oxygen species (ROS)-mediated death by stimulating SOD2 expression, increasing mitochondrial SOD2 activity and attenuating mitochondrial free radical ROS production, in association with increased mitochondrial capacity to produce H2O2, within the context of a more tumour stem cell-like phenotype. This effect can be reversed by the specific TrkA tyrosine kinase inhibitor GW441756, by the multi-kinase TrkA inhibitors K252a, CEP-701 and Gö6976, which inhibit SOD2 expression, and by siRNA knockdown of SOD2 expression, which restores the sensitivity of TrkAIII expressing SH-SY5Y cells to Rotenone, Paraquat and LY83583-induced mitochondrial free radical ROS production and ROS-mediated death. The data implicate the novel TrkAIII/SOD2 axis in promoting NB resistance to mitochondrial free radical-mediated death and staminality, and suggest that the combined use of TrkAIII and/or SOD2 inhibitors together with agents that induce mitochondrial free radical ROS-mediated death could provide a therapeutic advantage that may also target the stem cell niche in high TrkA expressing unfavourable NB.

Di Ianni, Natalia; Cappabianca, Lucia; Ragone, Marzia; Ianni, Giulia; Gulino, Alberto; Mackay, Andrew R.

2014-01-01

282

The TrkAIII Oncoprotein Inhibits Mitochondrial Free Radical ROS-Induced Death of SH-SY5Y Neuroblastoma Cells by Augmenting SOD2 Expression and Activity at the Mitochondria, within the Context of a Tumour Stem Cell-like Phenotype.  

Science.gov (United States)

The developmental and stress-regulated alternative TrkAIII splice variant of the NGF receptor TrkA is expressed by advanced stage human neuroblastomas (NBs), correlates with worse outcome in high TrkA expressing unfavourable tumours and exhibits oncogenic activity in NB models. In the present study, we report that constitutive TrkAIII expression in human SH-SY5Y NB cells inhibits Rotenone, Paraquat and LY83583-induced mitochondrial free radical reactive oxygen species (ROS)-mediated death by stimulating SOD2 expression, increasing mitochondrial SOD2 activity and attenuating mitochondrial free radical ROS production, in association with increased mitochondrial capacity to produce H2O2, within the context of a more tumour stem cell-like phenotype. This effect can be reversed by the specific TrkA tyrosine kinase inhibitor GW441756, by the multi-kinase TrkA inhibitors K252a, CEP-701 and Gö6976, which inhibit SOD2 expression, and by siRNA knockdown of SOD2 expression, which restores the sensitivity of TrkAIII expressing SH-SY5Y cells to Rotenone, Paraquat and LY83583-induced mitochondrial free radical ROS production and ROS-mediated death. The data implicate the novel TrkAIII/SOD2 axis in promoting NB resistance to mitochondrial free radical-mediated death and staminality, and suggest that the combined use of TrkAIII and/or SOD2 inhibitors together with agents that induce mitochondrial free radical ROS-mediated death could provide a therapeutic advantage that may also target the stem cell niche in high TrkA expressing unfavourable NB. PMID:24736663

Ruggeri, Pierdomenico; Farina, Antonietta R; Di Ianni, Natalia; Cappabianca, Lucia; Ragone, Marzia; Ianni, Giulia; Gulino, Alberto; Mackay, Andrew R

2014-01-01

283

CysLT1 receptor-induced human airway smooth muscle cells proliferation requires ROS generation, EGF receptor transactivation and ERK1/2 phosphorylation  

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Full Text Available Abstract Background Cysteine-containing leukotrienes (cysteinyl-LTs are pivotal inflammatory mediators that play important roles in the pathophysiology of asthma, allergic rhinitis, and other inflammatory conditions. In particular, cysteinyl-LTs exert a variety of effects with relevance to the aetiology of asthma such as smooth muscle contraction, eosinophil recruitment, increased microvascular permeability, enhanced mucus secretion and decreased mucus transport and, finally, airway smooth muscle cells (ASMC proliferation. We used human ASMC (HASMC to identify the signal transduction pathway(s of the leukotriene D4 (LTD4-induced DNA synthesis. Methods Proliferation of primary HASMC was measured by [3H]thymidine incorporation. Phosphorylation of EGF receptor (EGF-R and ERK1/2 was assessed with a polyclonal anti-EGF-R or anti-phosphoERKl/2 monoclonal antibody. A Ras pull-down assay kit was used to evaluate Ras activation. The production of reactive oxygen species (ROS was estimated by measuring dichlorodihydrofluorescein (DCF oxidation. Results We demonstrate that in HASMC LTD4-stimulated thymidine incorporation and potentiation of EGF-induced mitogenic signaling mostly depends upon EGF-R transactivation through the stimulation of CysLT1-R. Accordingly, we found that LTD4 stimulation was able to trigger the increase of Ras-GTP and, in turn, to activate ERK1/2. We show here that EGF-R transactivation was sensitive to pertussis toxin (PTX and phosphoinositide 3-kinase (PI3K inhibitors and that it occurred independently from Src activity, despite the observation of a strong impairment of LTD4-induced DNA synthesis following Src inhibition. More interestingly, CysLT1-R stimulation increased the production of ROS and N-acetylcysteine (NAC abolished LTD4-induced EGF-R phosphorylation and thymidine incorporation. Conclusion Collectively, our data demonstrate that in HASMC LTD4 stimulation of a Gi/o coupled CysLT1-R triggers the transactivation of the EGF-R through the intervention of PI3K and ROS. While PI3K and ROS involvement is an early event, the activation of Src occurs downstream of EGF-R activation and is followed by the classical Ras-ERK1/2 signaling pathway to control G1 progression and cell proliferation.

Capra Valérie

2006-03-01

284

Role of TLR4/NADPH oxidase/ROS-activated p38 MAPK in VCAM-1 expression induced by lipopolysaccharide in human renal mesangial cells  

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Full Text Available Abstract Background In bacteria-induced glomerulonephritis, Toll-like receptor 4 (TLR4 activation by lipopolysaccharide (LPS, a key component of the outer membranes of Gram-negative bacteria can increase oxidative stress and the expression of vascular cell adhesion molecule-1 (VCAM-1, which recruits leukocytes to the glomerular mesangium. However, the mechanisms underlying VCAM-1 expression induced by LPS are still unclear in human renal mesangial cells (HRMCs. Results We demonstrated that LPS induced VCAM-1 mRNA and protein levels associated with an increase in the promoter activity of VCAM-1, determined by Western blot, RT-PCR, and promoter assay. LPS-induced responses were inhibited by transfection with siRNAs of TLR4, myeloid differentiation factor 88 (MyD88, Nox2, Nox4, p47phox, c-Src, p38 MAPK, activating transcription factor 2 (ATF2, and p300 or pretreatment with the inhibitors of reactive oxygen species (ROS, edaravone, NADPH oxidase [apocynin (APO or diphenyleneiodonium chloride (DPI], c-Src (PP1, p38 MAPK (SB202190, and p300 (GR343. LPS induced NADPH oxidase activation, ROS production, and p47phox translocation from the cytosol to the membrane, which were reduced by PP1 or c-Src siRNA. We observed that LPS induced TLR4, MyD88, c-Src, and p47phox complex formation determined by co-immunoprecipitation and Western blot. We further demonstrated that LPS stimulated ATF2 and p300 phosphorylation and complex formation via a c-Src/NADPH oxidase/ROS/p38 MAPK pathway. Up-regulation of VCAM-1 led to enhancing monocyte adhesion to HRMCs challenged with LPS, which was inhibited by siRNAs of c-Src, p47phox, p38 MAPK, ATF2, and p300 or pretreatment with an anti-VCAM-1 neutralizing antibody. Conclusions In HRMCs, LPS-induced VCAM-1 expression was, at least in part, mediated through a TLR4/MyD88/ c-Src/NADPH oxidase/ROS/p38 MAPK-dependent p300 and ATF2 pathway associated with recruitment of monocyte adhesion to kidney. Blockade of these pathways may reduce monocyte adhesion via VCAM-1 suppression and attenuation of the inflammatory responses in renal diseases.

Lee I-Ta

2012-11-01

285

Intercultural Mediation  

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Full Text Available The Intercultural Mediator facilitates exchanges between people of different socio-cultural backgrounds and acts as a bridge between immigrants and national and local associations, health organizations, services and offices in order to foster integration of every single individual. As the use mediation increases, mediators are more likely to be involved in cross-cultural mediation, but only the best mediators have the opportunity to mediate cross border business disputes or international politics conflicts. This article attempts to provide a new perspective about the intercultural mediation.

Dragos Marian Radulescu

2012-11-01

286

Cypermethrin induces astrocyte damage: Role of aberrant Ca(2+), ROS, JNK, P38, matrix metalloproteinase 2 and migration related reelin protein.  

Science.gov (United States)

Cypermethrin is a synthetic type II pyrethroid, derived from a natural pyrethrin of the chrysanthemum plant. Cypermethrin-mediated neurotoxicity is well studied; however, relatively less is known of its effect on astrocyte development and migration. Astrocytes are the major components of blood brain barrier (BBB), and astrocyte damage along with BBB dysfunction impair the tight junction (TJ) proteins resulting in altered cell migration and neurodegeneration. Here, we studied the mechanism of cypermethin mediated rat astrocyte damage and BBB disruption, and determined any change in expression of proteins associated with cell migration. Through MTT assay we found that cypermethrin reduced viability of cultured rat astrocytes. Immunolabelling with astrocyte marker, glial fibrillary acidic protein, revealed alteration in astrocyte morphology. The astrocytes demonstrated an enhanced release of intracellular Ca(++) and ROS, and up-regulation in p-JNK and p-P38 levels in a time-dependent manner. Cypermethrin disrupted the BBB (in vivo) in developing rats and attenuated the expression of the extracellular matrix molecule (ECM) and claudin-5 in cultured astrocytes. We further observed an augmentation in the levels of matrix metalloproteinase 2 (MMP2), known to modulate cellular migration and disrupt the developmental ECM and BBB. We observed an increase in the levels of reelin, involved in cell migration, in cultured rat astrocytes. The reelin receptor, ?3?1integrin, and a mammalian cytosolic protein Disabled1 (Dab1) were also up-regulated. Overall, our study demonstrates that cypermethrin induces astrocyte injury via modulation in Ca(++), ROS, JNK and P38 pathways, which may alter MMP expression and reelin dependent astrocyte migration during brain development. PMID:24861934

Maurya, Shailendra Kumar; Mishra, Juhi; Tripathi, Vinay Kumar; Sharma, Rolee; Siddiqui, Mohammed Haris

2014-05-01

287

VEGF-induced ROS generation from NAD(P)H oxidases protects human leukemic cells from apoptosis.  

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Vascular endothelial growth factor (VEGF) and reactive oxygen species (ROS) play critical roles in vascular pathophysiology and in hematological malignancies. VEGF is supposed to utilize ROS as messenger intermediates downstream of the VEGF receptor-2. NAD(P)H oxidase (Nox) family is a major source of cellular ROS and is implicated in increased ROS production in tumor cells. We previously demonstrated that B1647 cells, a human leukemic cell line, express Nox2 and Nox4, both at mRNA and protein level. We suggest here that the VEGF-induced increase in ROS can be related to Nox2 and Nox4 activities. Nox-derived ROS are involved in early signaling events such as the autophosphorylation of VEGF receptor-2, and in the modulation of glucose uptake, a cellular activity strictly bound to VEGF-induced leukemic cell proliferation, as shown by experiments with antioxidants and Nox inhibitors and siRNA. Nox-generated ROS are required to sustain B1647 cell viability and proliferation; in fact, antioxidants such as EUK-134 or Nox inhibitors and siRNA direct cells to apoptotic cell death, suggesting that manipulation of cellular Nox2 and Nox4 could affect survival of leukemic cells. PMID:20428783

Maraldi, Tullia; Prata, Cecilia; Caliceti, Cristiana; Vieceli Dalla Sega, Francesco; Zambonin, Laura; Fiorentini, Diana; Hakim, Gabriele

2010-06-01

288

Di(2-ethylhexyl)phthalate stimulates Ca(2+) entry, chemotaxis and ROS production in human granulocytes.  

Science.gov (United States)

Di(2-ethylhexyl)phthalate (DEHP), a plasticizer widely used in polyvinyl chloride-based medical devices, is known to interfere with immune functions but the underlying molecular mechanisms remain elusive. In this in vitro study, we investigated DEHP effect on intracellular calcium concentration ([Ca(2+)](i)), chemotaxis and reactive oxygen species (ROS) production in human granulocytes. DEHP increased [Ca(2+)](i) by inducing a Ca(2+) influx from the extracellular medium. The effect was slow and inhibitable both by the membrane cation channel blockers SKF96365, econazole and 2-aminoethoxy diphenylborate and by the protein kinase C activator phorbol myristate acetate. The plasticizer stimulated both cell chemotaxis and ROS production; however, only the latter effect was dependent on DEHP-induced Ca(2+) influx. Collectively, our results indicate that DEHP interaction with human granulocytes leads to multiple and independent effects, each potentially contributing to inappropriate cell activation. PMID:19429244

Palleschi, Simonetta; Rossi, Barbara; Diana, Loretta; Silvestroni, Leopoldo

2009-05-22

289

Quantitative analyses of ROS and RNS production in breast cancer cell lines incubated with ferrocifens.  

Science.gov (United States)

Ferrocifens are an original class of ferrocifen-type breast cancer drugs. They possess anti-proliferative effects due to the association of the ferrocene moiety and the tamoxifen skeleton. In this work, fluorescence measurements indicated the production of reactive oxygen species (ROS) if hormone-dependent or -independent breast cancer cells were incubated with three hit ferrocifen compounds. Additionally, amperometry at ultramicroelectrodes was carried out to identify and quantify ROS and reactive nitrogen species (RNS) under stress conditions. Videomicroscopy was used to optimize the conditions employed for electrochemical investigations. Amperometry was then performed on two cell lines pre-incubated with each of the three ferrocifens. Interestingly, these results demonstrate that the presence of an aminoalkyl chain in the ferrocifen structure may confer a unique behavior toward both cell lines, in comparison with the two other compounds that lack this feature. PMID:24803138

Lu, Cong; Heldt, Jan-Martin; Guille-Collignon, Manon; Lemaître, Frédéric; Jaouen, Gérard; Vessičres, Anne; Amatore, Christian

2014-06-01

290

Andrographolide downregulates the v-Src and Bcr-Abl oncoproteins and induces Hsp90 cleavage in the ROS-dependent suppression of cancer malignancy.  

Science.gov (United States)

Andrographolide is a diterpenoid compound isolated from Andrographis paniculata that exhibits anticancer activity. We previously reported that andrographolide suppressed v-Src-mediated cellular transformation by promoting the degradation of Src. In the present study, we demonstrated the involvement of Hsp90 in the andrographolide-mediated inhibition of Src oncogenic activity. Using a proteomics approach, a cleavage fragment of Hsp90? was identified in andrographolide-treated cells. The concentration- and time-dependent induction of Hsp90 cleavage that accompanied the reduction in Src was validated in RK3E cells transformed with either v-Src or a human truncated c-Src variant and treated with andrographolide. In cancer cells, the induction of Hsp90 cleavage by andrographolide and its structural derivatives correlated well with decreased Src levels, the suppression of transformation, and the induction of apoptosis. Moreover, the andrographolide-induced Hsp90 cleavage, Src degradation, inhibition of transformation, and induction of apoptosis were abolished by a ROS inhibitor, N-acetyl-cysteine. Notably, Hsp90 cleavage, decreased levels of Bcr-Abl (another known Hsp90 client protein), and the induction of apoptosis were also observed in human K562 leukemia cells treated with andrographolide or its active derivatives. Together, we demonstrated a novel mechanism by which andrographolide suppressed cancer malignancy that involved inhibiting Hsp90 function and reducing the levels of Hsp90 client proteins. Our results broaden the molecular basis of andrographolide-mediated anticancer activity. PMID:24161787

Liu, Sheng-Hung; Lin, Chao-Hsiung; Liang, Fong-Ping; Chen, Pei-Fen; Kuo, Cheng-Deng; Alam, Mohd Mujahid; Maiti, Barnali; Hung, Shih-Kai; Chi, Chin-Wen; Sun, Chung-Ming; Fu, Shu-Ling

2014-01-15

291

Nutrient deprivation induces the Warburg effect through ROS/AMPK-dependent activation of pyruvate dehydrogenase kinase.  

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The Warburg effect is known to be crucial for cancer cells to acquire energy. Nutrient deficiencies are an important phenomenon in solid tumors, but the effect on cancer cell metabolism is not yet clear. In this study, we demonstrate that starvation of HeLa cells by incubation with Hank's buffered salt solution (HBSS) induced cell apoptosis, which was accompanied by the induction of reactive oxygen species (ROS) production and AMP-activated protein kinase (AMPK) phosphorylation. Notably, HBSS starvation increased lactate production, cytoplasmic pyruvate content and decreased oxygen consumption, but failed to change the lactate dehydrogenase (LDH) activity or the glucose uptake. We found that HBSS starvation rapidly induced pyruvate dehydrogenase kinase (PDK) activation and pyruvate dehydrogenase (PDH) phosphorylation, both of which were inhibited by compound C (an AMPK inhibitor), NAC (a ROS scavenger), and the dominant negative mutant of AMPK. Our data further revealed the involvement of ROS production in AMPK activation. Moreover, DCA (a PDK inhibitor), NAC, and compound C all significantly decreased HBSS starvation-induced lactate production accompanied by enhancement of HBSS starvation-induced cell apoptosis. Not only in HeLa cells, HBSS-induced lactate production and PDH phosphorylation were also observed in CL1.5, A431 and human umbilical vein endothelial cells. Taken together, we for the first time demonstrated that a low-nutrient condition drives cancer cells to utilize glycolysis to produce ATP, and this increases the Warburg effect through a novel mechanism involving ROS/AMPK-dependent activation of PDK. Such an event contributes to protecting cells from apoptosis upon nutrient deprivation. PMID:23376776

Wu, Ching-An; Chao, Yee; Shiah, Shine-Gwo; Lin, Wan-Wan

2013-05-01

292

Providing Routing Security Using ROS Protocol in MANET and Performance Comparison with AODV  

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Many of the proposed routing security solutions for the Mobile Ad hoc Networks (MANET) requires cryptographic techniques or a secret association between the communicating entities. These security solutions work well for the anticipated attacks but fails for unanticipated attacks. In this study, a Resiliency Oriented Secure (ROS) routing protocol for MANET is proposed. Present proposed protocol is a secure extension of AODV, in which each node suspects routing packet based on update time inter...

Martin Leo Manickam, J.; Shanmugavel, S.

2007-01-01

293

ROS Induction by Human Calprotectin in K562 and the Reversal Effect of Vitamin E  

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Calprotectin is a calcium and zinc-binding protein complex that is abundant in the cytosol of neutrophils released under inflammatory conditions. However, the exact role of this factor has not been elucidated. It is composed of 8 and 14 kDa subunits and has the capacity to induce apoptosis in various tumor cells in a zinc-reversible manner. Reactive Oxygen Species (ROS), which are the byproducts of normal cellular oxidative process, regulates the initiation of apoptotic signaling. Recently, i...

Yousefi, R.; Ardestani, S. K.; Imani, M.; Saboury, A. A.; Kariminia, A.

2007-01-01

294

Short chain fatty acids and cadmium cytotoxicity in ROS 17/2. 8 cells  

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ROS 17/2.8 rat osteosarcoma cells are extremely sensitive to the cytotoxic effects of Cd. In naive cells, sensitivity to Cd is associated with poor inducibility of metallothionein (MT). Treatment of ROS 17/2.8 cells with Na butyrate (NaB) results in increased resistance to Cd cytotoxicity and increased MT gene expression. The relation between the structure of short chain fatty acids and the alterations of Cd cytotoxicity in ROS 17/2.8 cells was investigated by culture of cells in the presence of 1 or 5 mM Na acetate, NaB, methyl butyrate, isobutyric acid, methyl isobutyrate and caproic acid. Among these compounds, only 5 mM NaB significantly increased the survival of ROS cells exposed to 0.1 to 10 {mu}M Cd and only NaB treatment was effective in increasing MT gene inducibility. The role of inhibition of DNA replication by NaB in cell resistance to Cd was examined. Among compounds tested, only 5 mM NaB significantly inhibited DNA synthesis. However, in cells in which DNA synthesis is inhibited by exposure to hydroxyurea, addition and removal of NaB from culture medium modulates cellular resistance to Cd. Hence, the effectiveness of NaB as a modifier of cell response to Cd is not due entirely to changes in cell proliferation. Additionally, rigid structural constraints for effectiveness dictate that only NaB is a potent modifier of resistance to Cd.

Thomas, D.J.; Angle, C.R.; Swanson, S.A. (Univ. of Nebraska, Omaha (United States))

1991-03-11

295

Superparamagnetic Iron Oxide Nanoparticles: Amplifying ROS Stress to Improve Anticancer Drug Efficacy  

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Superparamagnetic iron oxide nanoparticles (SPION) are an important and versatile nano- platform with broad biological applications. Despite extensive studies, the biological and pharmacological activities of SPION have not been exploited in therapeutic applications. Recently, ?-lapachone (?-lap), a novel anticancer drug, has shown considerable cancer specificity by selectively increasing reactive oxygen species (ROS) stress in cancer cells. In this study, we report that pH-responsive SPION...

Huang, Gang; Chen, Huabing; Dong, Ying; Luo, Xiuquan; Yu, Haijun; Moore, Zachary; Bey, Erik A.; Boothman, David A.; Gao, Jinming

2013-01-01

296

Insulin/IGF-1 and ROS signaling pathway cross-talk in aging and longevity determination  

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Regulation of hormonal, insulin/IGF-1 (Ins/IGF-1) signaling activities, and pathways of the intrinsic generation of reactive oxygen species (ROS) play a role in aging and longevity determination. In this review we discuss the cross-talk between these pathways as mechanisms of signaling that may be important factors in the regulation of aging and longevity. The balance of physiological processes controlling the rate of aging and longevity in several mouse mutants suggests the involvement of cr...

Papaconstantinou, John

2009-01-01

297

Impact of UV light on the plant cell wall, methane emissions and ROS production  

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This study presents the first attempt to combine the fields of ultraviolet (UV) photobiology, plant cell wall biochemistry, aerobic methane production and reactive oxygen species (ROS) mechanisms to investigate the effect of UV radiation on vegetation foliage. Following reports of a 17% increase in decomposition rates in oak (Quercus robur) due to increased UV, which were later ascribed to changes in cell wall carbohydrate extractability, this study investigated the effects of ...

Messenger, David James

2009-01-01

298

Mitochondrial Genome Instability and ROS Enhance Intestinal Tumorigenesis in APCMin/+ Mice  

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Alterations in mitochondrial oxidative phosphorylation have long been documented in tumors. Other types of mitochondrial dysfunction, including altered reactive oxygen species (ROS) production and apoptosis, also can contribute to tumorigenesis and cancer phenotypes. Furthermore, mutation and altered amounts of mitochondrial DNA (mtDNA) have been observed in cancer cells. However, how mtDNA instability per se contributes to cancer remains largely undetermined. Mitochondrial transcription fact...

2012-01-01

299

Surveillance-Activated Defenses Block the ROS–Induced Mitochondrial Unfolded Protein Response  

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Disturbance of cellular functions results in the activation of stress-signaling pathways that aim at restoring homeostasis. We performed a genome-wide screen to identify components of the signal transduction of the mitochondrial unfolded protein response (UPRmt) to a nuclear chaperone promoter. We used the ROS generating complex I inhibitor paraquat to induce the UPRmt, and we employed RNAi exposure post-embryonically to allow testing genes whose knockdown results in embryonic lethality. We i...

2013-01-01

300

Electron spin resonance spectroscopy for the study of nanomaterial-mediated generation of reactive oxygen species.  

Science.gov (United States)

Many of the biological applications and effects of nanomaterials are attributed to their ability to facilitate the generation of reactive oxygen species (ROS). Electron spin resonance (ESR) spectroscopy is a direct and reliable method to identify and quantify free radicals in both chemical and biological environments. In this review, we discuss the use of ESR spectroscopy to study ROS generation mediated by nanomaterials, which have various applications in biological, chemical, and materials science. In addition to introducing the theory of ESR, we present some modifications of the method such as spin trapping and spin labeling, which ultimately aid in the detection of short-lived free radicals. The capability of metal nanoparticles in mediating ROS generation and the related mechanisms are also presented. PMID:24673903

He, Weiwei; Liu, Yitong; Wamer, Wayne G; Yin, Jun-Jie

2014-03-01

 
 
 
 
301

Sodium arsenite induces ROS-dependent autophagic cell death in pancreatic ?-cells.  

Science.gov (United States)

Inorganic arsenic is a worldwide environmental pollutant. Inorganic arsenic's positive relationship with the incidence of type 2 diabetes mellitus arouses concerns associated with its etiology in diabetes among the general human population. In this study, the inhibitor of autophagosome formation, 3-methyladenine, protected the cells against sodium arsenite cytotoxicity, and the autophagy stimulator rapamycin further decreased the cell viability of sodium arsenite-treated INS-1 cells. These finding suggested the hypothesis that autophagic cell death contributed to sodium arsenite-induced cytotoxicity in INS-1 cells. Sodium arsenite increased the autophagosome-positive puncta in INS-1 cells observed under a fluorescence microscope, and this effect was confirmed by the elevated LC3-II levels detected through Western blot. The LC3 turnover assay indicated that the accumulation of autophagosomes in the arsenite-treated INS-1 cells was due to increased formation rather than impaired degradation. The pretreatment of INS-1 cells with the ROS inhibitor NAC reduced autophagosome formation and reversed the sodium arsenite cytotoxicity, indicating that sodium arsenite-induced autophagic cell death was ROS-dependent. In summary, the precise molecular mechanisms through which arsenic is related to diabetes have not been completely elucidated, but the ROS-dependent autophagic cell death of pancreatic ?-cells described in this study may help to elucidate the underlying mechanism. PMID:24859355

Zhu, Xue-Xin; Yao, Xiao-Feng; Jiang, Li-Ping; Geng, Cheng-Yan; Zhong, Lai-Fu; Yang, Guang; Zheng, Bai-Lu; Sun, Xian-Ce

2014-08-01

302

Neutrophil-derived ROS contribute to oxidative DNA damage induction by quartz particles.  

Science.gov (United States)

The carcinogenicity of respirable quartz is considered to be driven by reactive oxygen species (ROS) generation in association with chronic inflammation. The contribution of phagocyte-derived ROS to inflammation, oxidative stress, and DNA damage responses was investigated in the lungs of C57BL/6J wild-type and p47(phox-/-) mice, 24h after pharyngeal aspiration of DQ12 quartz (100 mg/kg bw). Bone-marrow-derived neutrophils from wild-type and p47(phox-/-) mice were used for parallel in vitro investigations in coculture with A549 human alveolar epithelial cells. Quartz induced a marked neutrophil influx in both wild-type and p47(phox-/-) mouse lungs. Significant increases in mRNA expression of the oxidative stress markers HO-1 and ?-GCS were observed only in quartz-treated wild-type animals. Oxidative DNA damage in lung tissue was not affected by quartz exposure and did not differ between p47(phox-/-) and WT mice. Differences in mRNA expression of the DNA repair genes OGG1, APE-1, DNA Pol?, and XRCC1 were also absent. Quartz treatment of cocultures containing wild-type neutrophils, but not p47(phox-/-) neutrophils, caused increased oxidative DNA damage in epithelial cells. Our study demonstrates that neutrophil-derived ROS significantly contribute to pulmonary oxidative stress responses after acute quartz exposure, yet their role in the associated induction of oxidative DNA damage could be shown only in vitro. PMID:20828610

van Berlo, Damien; Wessels, Anton; Boots, Agnes W; Wilhelmi, Verena; Scherbart, Agnes M; Gerloff, Kirsten; van Schooten, Frederik J; Albrecht, Catrin; Schins, Roel P F

2010-12-01

303

Influence of thiol stress on oxidative phosphorylation and generation of ROS in Streptomyces coelicolor  

Directory of Open Access Journals (Sweden)

Full Text Available Thiols play very important role in the intracellular redox homeostasis. Imbalance in the redox status leads to changes in the intracellular metabolism including respiration. Thiol stress, a reductive type of stress can also cause redox imbalance. When Gram-positive bacterium Strep- tomyces coelicolor was exposed to thiol stress, catalaseA was induced. Induction of catalaseA is the consequence of elevation of ROS (reactive oxygen species. The two major sources of reactive oxygen species are Fenton reaction and slippage of electrons from electron transport chain during respiration. Hence, the effect of thiol stress was checked on the rate of oxidative phosphorylation in S. coelicolor. We found correlation in the increase of oxidative phosphorylation rate and the generation of ROS, subsequently leading to induction of catalase. It was observed that thiol stress does not affect the functionality of the individual complexes of the ETC, but still there was an increase in the overall respiration, which may lead to generation of more ROS leading to induction of catalase.

Hemendra J. Vekaria

2010-11-01

304

KRIT1 loss of function causes a ROS-dependent upregulation of c-Jun  

Science.gov (United States)

Loss-of-function mutations in the KRIT1 gene (CCM1) have been associated with the pathogenesis of cerebral cavernous malformations (CCM), a major cerebrovascular disease. However, KRIT1 functions and CCM pathogenetic mechanisms remain incompletely understood. Indeed, recent experiments in animal models have clearly demonstrated that the homozygous loss of KRIT1 is not sufficient to induce CCM lesions, suggesting that additional factors are necessary to cause CCM disease. Previously, we found that KRIT1 is involved in the maintenance of the intracellular reactive oxygen species (ROS) homeostasis to prevent ROS-induced cellular dysfunctions, including a reduced ability to maintain a quiescent state. Here, we show that KRIT1 loss of function leads to enhanced expression and phosphorylation of the redox-sensitive transcription factor c-Jun, as well as induction of its downstream target COX-2, in both cellular models and human CCM tissues. Furthermore, we demonstrate that c-Jun upregulation can be reversed by either KRIT1 re-expression or ROS scavenging, whereas KRIT1 overexpression prevents forced upregulation of c-Jun induced by oxidative stimuli. Taken together with the reported role of c-Jun in vascular dysfunctions triggered by oxidative stress, our findings shed new light on the molecular mechanisms underlying KRIT1 function and CCM pathogenesis.

Goitre, Luca; De Luca, Elisa; Braggion, Stefano; Trapani, Eliana; Guglielmotto, Michela; Biasi, Fiorella; Forni, Marco; Moglia, Andrea; Trabalzini, Lorenza; Retta, Saverio Francesco

2014-01-01

305

ROS Induction by Human Calprotectin in K562 and the Reversal Effect of Vitamin E  

Directory of Open Access Journals (Sweden)

Full Text Available Calprotectin is a calcium and zinc-binding protein complex that is abundant in the cytosol of neutrophils released under inflammatory conditions. However, the exact role of this factor has not been elucidated. It is composed of 8 and 14 kDa subunits and has the capacity to induce apoptosis in various tumor cells in a zinc-reversible manner. Reactive Oxygen Species (ROS, which are the byproducts of normal cellular oxidative process, regulates the initiation of apoptotic signaling. Recently, it has been shown that calprotectin plays an important role in phagocyte NADPH oxidase activation. In addition, the pretreatment of colon cancer cells with the antioxidant N-Acetyl-L-Cysteine (NAC prevents apoptosis inducs by calprotectin. In the present study, we further investigate the growth inhibitory effect of calprotectin via ROS induction. For the first time it is shown that human calprotectin induced ROS and apoptosis in K562 cells revealed by conversion of Dichlorodihydroflurescin Diacetate (DCFH2-DA to DCF and the enhancement of cell surface binding to Annexin V-FITC appropriately. More over, it is demonstrated that naturally occurring antioxidant vitamin E (50-200 ?M significantly reversed the effect of calprotectin proposing the beneficial effect of vitamin E as a natural antioxidant in restriction of calprotectin cytotoxic activity during excessive production of this protein.

2007-01-01

306

Loss of UCP2 Attenuates Mitochondrial Dysfunction without Altering ROS Production and Uncoupling Activity  

Science.gov (United States)

Although mitochondrial dysfunction is often accompanied by excessive reactive oxygen species (ROS) production, we previously showed that an increase in random somatic mtDNA mutations does not result in increased oxidative stress. Normal levels of ROS and oxidative stress could also be a result of an active compensatory mechanism such as a mild increase in proton leak. Uncoupling protein 2 (UCP2) was proposed to play such a role in many physiological situations. However, we show that upregulation of UCP2 in mtDNA mutator mice is not associated with altered proton leak kinetics or ROS production, challenging the current view on the role of UCP2 in energy metabolism. Instead, our results argue that high UCP2 levels allow better utilization of fatty acid oxidation resulting in a beneficial effect on mitochondrial function in heart, postponing systemic lactic acidosis and resulting in longer lifespan in these mice. This study proposes a novel mechanism for an adaptive response to mitochondrial cardiomyopathy that links changes in metabolism to amelioration of respiratory chain deficiency and longer lifespan.

Kukat, Alexandra; Dogan, Sukru Anil; Edgar, Daniel; Mourier, Arnaud; Jacoby, Christoph; Maiti, Priyanka; Mauer, Jan; Becker, Christina; Senft, Katharina; Wibom, Rolf; Kudin, Alexei P.; Hultenby, Kjell; Flogel, Ulrich; Rosenkranz, Stephan; Ricquier, Daniel; Kunz, Wolfram S.; Trifunovic, Aleksandra

2014-01-01

307

Dynamic activation of Src induced by low-power laser irradiation in living cells mediated by reactive oxygen species  

Science.gov (United States)

Low-power laser irradiation (LPLI) leads to photochemical reaction and then activates intracellular several signaling pathway. Reactive oxygen species (ROS) are considered to be the primary messengers produced by LPLI. Here, we studied the signaling pathway mediated by ROS upon the stimulation of LPLI. Src tyrosine kinases are well-known targets of ROS and can be activated by oxidative events. Using a Src reporter based on fluorescence resonance energy transfer (FRET) technique, we visualized the dynamic Src activation in Hela cells immediately after LPLI. Moreover, Src activity was enhanced by increasing the duration of LPLI. In addition, our results suggested that ROS were key mediators of Src activation, as ROS scavenger, vitamin C decreased and exogenous H2O2 increased the activity of Src. Meanwhile, Gö6983 loading did not block the effect of LPLI. CCK-8 experiments proved that cell vitality was prominently improved by LPLI with all the doses we applied in our experiments ranging from 3 to 25J/cm2. The results indicated that LPLI/ROS/Src pathway may be involved in the LPLI biostimulation effects.

Zhang, Juntao; Gao, Xuejuan; Xing, Da; Liu, Lei

2007-10-01

308

Relationship between oxidative stress and hepatic glutathione levels in ethanol-mediated apoptosis of polarized hepatic cells  

Directory of Open Access Journals (Sweden)

Full Text Available AIM: To investigate the role of reactive oxygen species (ROS in ethanol-mediated cell death of polarized hepatic (WIF-B cells.METHODS: In this work, WIF-B cultures were treated with pyrazole (inducer of cytochrome P4502E1, CYP2E1 and/or L-buthionine sulfoximine (BSO, a known inhibitor of hepatic glutathione (GSH, followed by evaluation of ROS production, antioxidant levels, and measures of cell injury (apoptosis and necrosis.RESULTS: The results revealed that ethanol treatment alone caused a significant two-fold increase in the activation of caspase-3 as well as a similar doubling in ROS. When the activity of the CYP2E1 was increased by pyrazole pretreatment, an additional two-fold elevation in ROS was detected. However, the CYP2E1-related ROS elevation was not accompanied with a correlative increase in apoptotic cell injury, but rather was found to be associated with an increase in necrotic cell death. Interestingly, when the thiol status of the cells was manipulated using BSO, the ethanol-induced activation of caspase-3 was abrogated. Additionally, ethanol-treated cells displayed enhanced susceptibility to Fas-mediated apoptosis that was blocked by GSH depletion as a result of diminished caspase-8 activity.CONCLUSION: Apoptotic cell death induced as a consequence of ethanol metabolism is not completely dependent upon ROS status but is dependent on sustained GSH levels.

Benita L McVicker, Pamela L Tuma, Kusum K Kharbanda, Serene ML Lee, Dean J Tuma

2009-06-01

309

Lead-zinc interactions in the production of osteocalcin by ROS 17/2.8 osteoblastic bone cells  

International Nuclear Information System (INIS)

The serum level of osteocalcin, a bone specific protein produced by osteoblasts and used clinically as a marker of osteoblast acceptive, is decreased in lead intoxicated children. Previous studies suggest that the reduced osteocalcin production appears to be the result of impaired transcriptional regulation of this 1,25-dihydroxyvitamin D3 gene product, and not translation. As part of a study to investigate the potential interaction of Pb2+ with Zn2+, and with the zinc fingers of the vitamin D receptor, ROS cells were treated with 0, 5, 10, or 25 ?M lead acetate for 24 hr, in the presence of 10, 30, or 50 ?M Zn followed by an additional 24 hr treatment with lead with 1,25-dihydroxyvitamin D3 (100 pg/ml media). At the end of this period a radioimmunoassay was conducted to determine the amount of osteocalcin in the cells and secreted in the media. 1,25-dihydroxyvitamin D3 caused an increase in osteocalcin secreted into the media in cultures containing 0 ?M lead, but this increase was inhibited by lead in a concentration dependent manner, so that osteocalcin secretion in 10 or 25 ?M lead treated groups was less than cultures without 1,25-dihydroxyvitamin D3 treatment. This inhibitory effect of lead was blocked by increasing the medium zinc concentration of 50 ?M. Increasing medium Pb2+ concentrations decreased the amount of 65Zn taken up by cells by ?30%, which was nullified by increasing medium Zn. These results suggest that lead produces a localized and specific Zn deficiency in the vitamin D receptor zinc finger, and perhaps other zinc metalloproteins, and that these effects of lead are not mediated through general effects on RNA or protein synthesis

1991-03-01

310

Dihydroartemisinin induces autophagy and inhibits the growth of iron-loaded human myeloid leukemia K562 cells via ROS toxicity  

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? DHA induced K562 cells autophagy followed by LC3-II protein expression. ? The DHA-induced autophagy might be ROS dependent. ? Inhibition of K562 cell proliferation by DHA was also dependent upon iron decrease.

Wang, Zeng; Hu, Wei; Zhang, Jia-li; Wu, Xiu-hua; Zhou, Hui-jun

2012-01-01

311

ROS-mediated genotoxicity of asbestos-cement in mammalian lung cells in vitro  

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Abstract Asbestos is a known carcinogen and co-carcinogen. It is a persisting risk in our daily life due to its use in building material as asbestos-cement powder. The present study done on V79-cells (Chinese hamster lung cells) demonstrates the cytotoxic and genotoxic potential of asbestos-cement powder (ACP) in comparison with chrysotile asbestos. A co-exposure of chrysotile and ACP was tested using the cell viability test and the micronucleus assay. The kinetochore analysis had b...

Dopp Elke; Yadav Santosh; Ansari Furquan; Bhattacharya Kunal; von Recklinghausen Ursula; Rauen Ursula; Rödelsperger Klaus; Shokouhi Behnaz; Geh Stefan; Rahman Qamar

2005-01-01

312

Activation of Nrf2-mediated oxidative stress response in macrophages by hypochlorous acid  

International Nuclear Information System (INIS)

er HOCl challenge conditions, suggesting intracellular ROS-scavenging capacity affects HOCl-induced Nrf2 activation. Importantly, pre-activation of Nrf2 with low concentrations of pro-oxidants protected the cells against HOCl-induced cell damage. Taken together, we provide direct evidence that HOCl activates Nrf2-mediated antioxidant response, which protects cells from oxidative damage

2008-02-01

313

Toward real-time regional earthquake simulation II: Real-time Online earthquake Simulation (ROS) of Taiwan earthquakes  

Science.gov (United States)

We developed a Real-time Online earthquake Simulation system (ROS) to simulate regional earthquakes in Taiwan. The ROS uses a centroid moment tensor solution of seismic events from a Real-time Moment Tensor monitoring system (RMT), which provides all the point source parameters including the event origin time, hypocentral location, moment magnitude and focal mechanism within 2 min after the occurrence of an earthquake. Then, all of the source parameters are automatically forwarded to the ROS to perform an earthquake simulation, which is based on a spectral-element method (SEM). A new island-wide, high resolution SEM mesh model is developed for the whole Taiwan in this study. We have improved SEM mesh quality by introducing a thin high-resolution mesh layer near the surface to accommodate steep and rapidly varying topography. The mesh for the shallow sedimentary basin is adjusted to reflect its complex geometry and sharp lateral velocity contrasts. The grid resolution at the surface is about 545 m, which is sufficient to resolve topography and tomography data for simulations accurate up to 1.0 Hz. The ROS is also an infrastructural service, making online earthquake simulation feasible. Users can conduct their own earthquake simulation by providing a set of source parameters through the ROS webpage. For visualization, a ShakeMovie and ShakeMap are produced during the simulation. The time needed for one event is roughly 3 min for a 70 s ground motion simulation. The ROS is operated online at the Institute of Earth Sciences, Academia Sinica (http://ros.earth.sinica.edu.tw/). Our long-term goal for the ROS system is to contribute to public earth science outreach and to realize seismic ground motion prediction in real-time.

Lee, Shiann-Jong; Liu, Qinya; Tromp, Jeroen; Komatitsch, Dimitri; Liang, Wen-Tzong; Huang, Bor-Shouh

2014-06-01

314

Modulation of rosR Expression and Exopolysaccharide Production in Rhizobium leguminosarum bv. trifolii by Phosphate and Clover Root Exudates  

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Full Text Available The acidic exopolysaccharide (EPS secreted in large amounts by the symbiotic nitrogen-fixing bacterium Rhizobium leguminosarum bv. trifolii is required for the establishment of an effective symbiosis with the host plant Trifolium spp. EPS biosynthesis in rhizobia is a very complex process regulated at both transcriptional and post-transcriptional levels and influenced by various nutritional and environmental conditions. The R. leguminosarum bv. trifolii rosR gene encodes a transcriptional regulator with a C2H2 type zinc-finger motif involved in positive regulation of EPS synthesis. In silico sequence analysis of the 450-bp long rosR upstream region revealed the presence of several inverted repeats (IR1 to IR6 and motifs with significant identity to consensus sequences recognized by PhoB and LysR-type proteins associated with phosphate- and flavonoid-dependent gene regulation in R. leguminosarum. Using a set of sequentially truncated rosR-lacZ transcriptional fusions, the role of the individual motifs and the effect of phosphate and clover root exudates on rosR expression were established. In addition, the significance of IR4 inverted repeats in the repression, and P2–10 hexamer in the activation of rosR transcription, respectively, was found. The expression of rosR increased in the presence of phosphate (0.1–20 mM and clover root exudates (10 ?M. PHO boxes and the LysR motif located upstream of the rosR translation start site were engaged in the regulation of rosR transcription. The synthesis of EPS and biofilm formation decreased at high phosphate concentrations, but increased in the presence of clover root exudates, indicating a complex regulation of these processes.

Anna Skorupska

2011-06-01

315

Generation of reactive oxygen species (ROS) is a key factor for stimulation of macrophage proliferation by ceramide 1-phosphate  

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We previously demonstrated that ceramide 1-phosphate (C1P) is mitogenic for fibroblasts and macrophages. However, the mechanisms involved in this action were only partially described. Here, we demonstrate that C1P stimulates reactive oxygen species (ROS) formation in primary bone marrow-derived macrophages, and that ROS are required for the mitogenic effect of C1P. ROS production was dependent upon prior activation of NADPH oxidase by C1P, which was determined by measuring phosphorylation of the p40phox subunit and translocation of p47phox from the cytosol to the plasma membrane. In addition, C1P activated cytosolic calcium-dependent phospholipase A{sub 2} and protein kinase C-{alpha}, and NADPH oxidase activation was blocked by selective inhibitors of these enzymes. These inhibitors, and inhibitors of ROS production, blocked the mitogenic effect of C1P. By using BHNB-C1P (a photolabile caged-C1P analog), we demonstrate that all of these C1P actions are caused by intracellular C1P. It can be concluded that the enzyme responsible for C1P-stimulated ROS generation in bone marrow-derived macrophages is NADPH oxidase, and that this enzyme is downstream of PKC-{alpha} and cPLA{sub 2}-{alpha} in this pathway. -- Highlights: Black-Right-Pointing-Pointer Ceramide 1-phosphate (C1P) stimulates reactive oxygen species (ROS) formation. Black-Right-Pointing-Pointer The enzyme responsible for ROS generation by C1P in macrophages is NADPH oxidase. Black-Right-Pointing-Pointer NADPH oxidase lies downstream of cPLA{sub 2}-{alpha} and PKC-{alpha} in this pathway. Black-Right-Pointing-Pointer ROS generation is essential for the stimulation of macrophage proliferation by C1P.

Arana, Lide; Gangoiti, Patricia; Ouro, Alberto; Rivera, Io-Guane; Ordonez, Marta; Trueba, Miguel [Department of Biochemistry and Molecular Biology, Faculty of Science and Technology, University of the Basque Country, 48080 Bilbao (Spain); Lankalapalli, Ravi S.; Bittman, Robert [Department of Chemistry and Biochemistry, Queens College of The City University of New York, Flushing, NY 11367-1597 (United States); Gomez-Munoz, Antonio, E-mail: antonio.gomez@ehu.es [Department of Biochemistry and Molecular Biology, Faculty of Science and Technology, University of the Basque Country, 48080 Bilbao (Spain)

2012-02-15

316

Novel role of p66Shc in ROS-dependent VEGF signaling and angiogenesis in endothelial cells  

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p66Shc, a longevity adaptor protein, is demonstrated as a key regulator of reactive oxygen species (ROS) metabolism involved in aging and cardiovascular diseases. Vascular endothelial growth factor (VEGF) stimulates endothelial cell (EC) migration and proliferation primarily through the VEGF receptor-2 (VEGFR2). We have shown that ROS derived from Rac1-dependent NADPH oxidase are involved in VEGFR2 autophosphorylation and angiogenic-related responses in ECs. However, a role of p66Shc in VEGF ...

Oshikawa, Jin; Kim, Seok-jo; Furuta, Eiji; Caliceti, Cristiana; Chen, Gin-fu; Mckinney, Ronald D.; Kuhr, Frank; Levitan, Irena; Fukai, Tohru; Ushio-fukai, Masuko

2012-01-01

317

Generation of reactive oxygen species (ROS) is a key factor for stimulation of macrophage proliferation by ceramide 1-phosphate  

International Nuclear Information System (INIS)

We previously demonstrated that ceramide 1-phosphate (C1P) is mitogenic for fibroblasts and macrophages. However, the mechanisms involved in this action were only partially described. Here, we demonstrate that C1P stimulates reactive oxygen species (ROS) formation in primary bone marrow-derived macrophages, and that ROS are required for the mitogenic effect of C1P. ROS production was dependent upon prior activation of NADPH oxidase by C1P, which was determined by measuring phosphorylation of the p40phox subunit and translocation of p47phox from the cytosol to the plasma membrane. In addition, C1P activated cytosolic calcium-dependent phospholipase A2 and protein kinase C-?, and NADPH oxidase activation was blocked by selective inhibitors of these enzymes. These inhibitors, and inhibitors of ROS production, blocked the mitogenic effect of C1P. By using BHNB-C1P (a photolabile caged-C1P analog), we demonstrate that all of these C1P actions are caused by intracellular C1P. It can be concluded that the enzyme responsible for C1P-stimulated ROS generation in bone marrow-derived macrophages is NADPH oxidase, and that this enzyme is downstream of PKC-? and cPLA2-? in this pathway. -- Highlights: ? Ceramide 1-phosphate (C1P) stimulates reactive oxygen species (ROS) formation. ? The enzyme responsible for ROS generation by C1P in macrophages is NADPH oxidase. ? NADPH oxidase lies downstream of cPLA2-? and PKC-? in this pathway. ? ROS generation is essential for the stimulation of macrophage proliferation by C1P.

2012-02-15

318

NADPH Oxidase versus Mitochondria-Derived ROS in Glucose-Induced Apoptosis of Pericytes in Early Diabetic Retinopathy  

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Objectives. Using apocynin (inhibitor of NADPH oxidase), and Mitoquinol 10 nitrate (MitoQ; mitochondrial-targeted antioxidant), we addressed the importance of mitochondria versus NADPH oxidase-derived ROS in glucose-induced apoptosis of pericytes. Methods. NADPH oxidase was localised using Western blot analysis and cytochrome C reduction assay. Apoptosis was detected by measuring caspase-3 activity. Intracellular glucose concentration, ROS formation and N?-(carboxymethyl) lysine (CML) ...

Mustapha, Nik M.; Tarr, Joanna M.; Kohner, Eva M.; Chibber, Rakesh

2010-01-01

319

Rhizobium leguminosarum bv. trifolii rosR is required for interaction with clover, biofilm formation and adaptation to the environment  

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Full Text Available Abstract Background Rhizobium leguminosarum bv. trifolii is a symbiotic nitrogen-fixing bacterium that elicits nodules on roots of host plants Trifolium spp. Bacterial surface polysaccharides are crucial for establishment of a successful symbiosis with legumes that form indeterminate-type nodules, such as Trifolium, Pisum, Vicia, and Medicago spp. and aid the bacterium in withstanding osmotic and other environmental stresses. Recently, the R. leguminosarum bv. trifolii RosR regulatory protein which controls exopolysaccharide production has been identified and characterized. Results In this work, we extend our earlier studies to the characterization of rosR mutants which exhibit pleiotropic phenotypes. The mutants produce three times less exopolysaccharide than the wild type, and the low-molecular-weight fraction in that polymer is greatly reduced. Mutation in rosR also results in quantitative alterations in the polysaccharide constituent of lipopolysaccharide. The rosR mutants are more sensitive to surface-active detergents, antibiotics of the beta-lactam group and some osmolytes, indicating changes in the bacterial membranes. In addition, the rosR mutants exhibit significant decrease in motility and form a biofilm on plastic surfaces, which differs significantly in depth, architecture, and bacterial viability from that of the wild type. The most striking effect of rosR mutation is the considerably decreased attachment and colonization of root hairs, indicating that the mutation affects the first stage of the invasion process. Infection threads initiate at a drastically reduced rate and frequently abort before they reach the base of root hairs. Although these mutants form nodules on clover, they are unable to fix nitrogen and are outcompeted by the wild type in mixed inoculations, demonstrating that functional rosR is important for competitive nodulation. Conclusions This report demonstrates the significant role RosR regulatory protein plays in bacterial stress adaptation and in the symbiotic relationship between clover and R. leguminosarum bv. trifolii 24.2.

Piersiak Tomasz

2010-11-01

320

Iron Overload Induced Apoptotic Cell Death in Isolated Rat Hepatocytes Mediated by Reactive Oxygen Species  

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Full Text Available Isolated rat hepatocytes in culture were incubated with different concentrations of iron-sorbitol (50, 100, 150, and 200 µM to assess the changes in reactive oxygen species (ROS and lipid peroxidation leading to apoptotic hepatocyte cell death. The viability of hepatocytes was declined depending on the iron concentration. One hour incubation of the cells with 100 µM iron resulted in decreased of the hepatocyte viability down to 50% (EC50 µM. Cellular glutathione (GSH was depleted depending on the concentration of iron added to the hepatocytes in culture. Decline in cellular GSH was associated with elevation in reactive oxygen species (ROS generation and formation of thiobarbituric acid reactive substances (TBARS as index of lipid peroxidation. TBARS concentration was elevated in hepatocytes exposed to >100 µM of iron for 40 min. A significant increase in ROS formation was also observed in cells incubated with 75 µM of iron for 60 and 120 min. The consequences of ROS-mediated damages to hepatocytes were observed by DNA fragmentation, nuclear staining by propidium iddide and finally with induction of apoptotic hepatocyte cell death. Terminal deoxynucleotie transferase-mediated dUTP nick end labeling i.e. TUNEL assay (In situ- cell death-detection kit and nuclear staining were also used to confirm apoptosis. These data clearly show that iron overload can cause apoptotic cell death in isolated hepatocytes and generation of ROS precedes other changes related to oxidative stress.

Abdolamir Allameh

2008-01-01

 
 
 
 
321

Prooxidant properties of p66shc are mediated by mitochondria in human cells.  

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p66shc is a protein product of an mRNA isoform of SHC1 gene that has a pro-oxidant and pro-apoptotic activity and is implicated in the aging process. Mitochondria were suggested as a major source of the p66shc-mediated production of reactive oxygen species (ROS), although the underlying mechanisms are poorly understood. We studied effects of p66shc on oxidative stress induced by hydrogen peroxide or by serum deprivation in human colon carcinoma cell line RKO and in diploid human dermal fibroblasts (HDFs). An shRNA-mediated knockdown of p66shc suppressed and an overexpression of a recombinant p66shc stimulated the production of ROS in the both models. This effect was not detected in the mitochondrial DNA-depleted ?0-RKO cells that do not have the mitochondrial electron transport chain (ETC). The p66shc-dependent accumulation of mitochondrial ROS was detected with HyPer-mito, a mitochondria-targeted fluorescent protein sensor for hydrogen peroxide. The fragmentation of mitochondria induced by mitochondrial ROS was significantly reduced in the p66shc deficient RKO cells. Mitochondria-targeted antioxidants SkQ1 and SkQR1 also decreased the oxidative stress induced by hydrogen peroxide or by serum deprivation. Together the data indicate that the p66shc-dependant ROS production during oxidative stress has mitochondrial origin in human normal and cancer cells. PMID:24618848

Galimov, Evgeny R; Chernyak, Boris V; Sidorenko, Alena S; Tereshkova, Alesya V; Chumakov, Peter M

2014-01-01

322

Ca2+-modulated ROS-GC1 transduction system in testes and its presence in the spermatogenic cells  

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ROS-GC1 belongs to the Ca2+-modulated sub-family of membrane guanylate cyclases. It primarily exists and is linked with signaling of the sensory neurons – sight, smell, taste, and pinealocytes. Exceptionally, it is also present and is Ca2+-modulated in t he non-neuronal cells, the sperm cells in the testes, where S100B protein serves as its Ca2+ sensor. The present report demonstrates the identification of an additional Ca2+ sensor of ROS-GC1 in the testes, neurocalcin ?. Through mouse molecular genetic models, it compares and quantifies the relative input of the S100B and neurocalcin ? in regulating the Ca2+ signaling of ROS-GC1 transduction machinery, and via immunochemistry it demonstrates the co-presence of neurocalcin ? and ROS-GC1 in the spermatogenic cells of the testes. The suggestion is that in more ways than one the Ca2+-modulated ROS-GC1 transduction system is linked with the testicular function. This non-neuronal transduction system may represent an illustration of the ROS-GC1 expanding role in the trans-signaling of the neural and non-neural systems.

Jankowska, Anna; Sharma, Rameshwar K.; Duda, Teresa

2014-01-01

323

Ca(2+)-modulated ROS-GC1 transduction system in testes and its presence in the spermatogenic cells.  

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ROS-GC1 belongs to the Ca(2+)-modulated sub-family of membrane guanylate cyclases. It primarily exists and is linked with signaling of the sensory neurons - sight, smell, taste, and pinealocytes. Exceptionally, it is also present and is Ca(2+)-modulated in t he non-neuronal cells, the sperm cells in the testes, where S100B protein serves as its Ca(2+) sensor. The present report demonstrates the identification of an additional Ca(2+) sensor of ROS-GC1 in the testes, neurocalcin ?. Through mouse molecular genetic models, it compares and quantifies the relative input of the S100B and neurocalcin ? in regulating the Ca(2+) signaling of ROS-GC1 transduction machinery, and via immunochemistry it demonstrates the co-presence of neurocalcin ? and ROS-GC1 in the spermatogenic cells of the testes. The suggestion is that in more ways than one the Ca(2+)-modulated ROS-GC1 transduction system is linked with the testicular function. This non-neuronal transduction system may represent an illustration of the ROS-GC1 expanding role in the trans-signaling of the neural and non-neural systems. PMID:24808824

Jankowska, Anna; Sharma, Rameshwar K; Duda, Teresa

2014-01-01

324

ROS play a critical role in the differentiation of alternatively activated macrophages and the occurrence of tumor-associated macrophages.  

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Differentiation to different types of macrophages determines their distinct functions. Tumor-associated macrophages (TAMs) promote tumorigenesis owing to their proangiogenic and immune-suppressive functions similar to those of alternatively activated (M2) macrophages. We report that reactive oxygen species (ROS) production is critical for macrophage differentiation and that inhibition of superoxide (O(2-)) production specifically blocks the differentiation of M2 macrophages. We found that when monocytes are triggered to differentiate, O(2-) is generated and is needed for the biphasic ERK activation, which is critical for macrophage differentiation. We demonstrated that ROS elimination by butylated hydroxyanisole (BHA) and other ROS inhibitors blocks macrophage differentiation. However, the inhibitory effect of ROS elimination on macrophage differentiation is overcome when cells are polarized to classically activated (M1), but not M2, macrophages. More importantly, the continuous administration of the ROS inhibitor BHA efficiently blocked the occurrence of TAMs and markedly suppressed tumorigenesis in mouse cancer models. Targeting TAMs by blocking ROS can be a potentially effective method for cancer treatment. PMID:23752925

Zhang, Yan; Choksi, Swati; Chen, Kun; Pobezinskaya, Yelena; Linnoila, Ilona; Liu, Zheng-Gang

2013-07-01

325

NADPH Oxidase versus Mitochondria-Derived ROS in Glucose-Induced Apoptosis of Pericytes in Early Diabetic Retinopathy.  

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Objectives. Using apocynin (inhibitor of NADPH oxidase), and Mitoquinol 10 nitrate (MitoQ; mitochondrial-targeted antioxidant), we addressed the importance of mitochondria versus NADPH oxidase-derived ROS in glucose-induced apoptosis of pericytes. Methods. NADPH oxidase was localised using Western blot analysis and cytochrome C reduction assay. Apoptosis was detected by measuring caspase-3 activity. Intracellular glucose concentration, ROS formation and Nepsilon-(carboxymethyl) lysine (CML) content were measured using Amplex Red assay kit, dihydroethidium (DHE), and competitive immunoabsorbant enzyme-linked assay (ELISA), respectively. Results. NADPH oxidase was localised in the cytoplasm of pericytes suggesting ROS production within intracellular compartments. High glucose (25 mM) significantly increased apoptosis, intracellular glucose concentration, and CML content. Apoptosis was associated with increased gp91phox expression, activity of NADPH oxidase, and intracellular ROS production. Apocynin and not MitoQ significantly blunted the generation of ROS, formation of intracellular CML and apoptosis. Conclusions. NADPH oxidase and not mitochondria-derived ROS is responsible for the accelerated apoptosis of pericytes in diabetic retinopathy. PMID:20652059

Mustapha, Nik M; Tarr, Joanna M; Kohner, Eva M; Chibber, Rakesh

2010-01-01

326

Ca2+-modulated ROS-GC1 transduction system in testes and its presence in the spermatogenic cells  

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Full Text Available ROS-GC1 belongs to the Ca2+-modulated sub-family of membrane guanylate cyclases. It primarily exists and is linked with signaling of the sensory neurons – sight, smell, taste and pinealocytes. Exceptionally, it is also present and is Ca2+-modulated in the non-neuronal cells, the sperm cells in the testes, where S100B protein serves its Ca2+ sensor. The present report demonstrates the identification of an additional Ca2+ sensor of ROS-GC1 in the testes, neurocalcin ?. Through mouse molecular genetic models, it compares and quantifies the relative input of the S100B and neurocalcin ? in regulating the Ca2+ signaling of ROS-GC1 transduction machinery, and via immunochemistry it demonstrates the co-presence of neurocalcin ? and ROS-GC1 in the spermatogenic cells of the testes. The suggestion is that in more ways than one the Ca2+-modulated ROS-GC1 transduction system is linked with the testicular function. This non-neuronal transduction system may represent an illustration of the ROS-GC1 expanding role in the trans-signaling of the neural and non-neural systems.

AnnaJankowska

2014-04-01

327

Effect of LLLT on the level of ATP and ROS from organ of corti cells  

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It is well established that ototoxic antibiotics and acoustic trauma can damage cochlear hair cells and cause hearing loss. Previous studies using transcanal LLLT (Low level laser therapy) showed that LLLT can promote recovery of hearing thresholds and cochlear hair cells. However, its mechanism has not been studied. Aim: The aim of this study is to investigate the mechanism of hearing recovery from gentamicin induced ototoxic hearing loss by LLLT. Methods: HEI- OC1 (House ear institute organ of Corti) cells were cultured for 18 hours and ototoxicity was induced by gentamicin (GM) treatment to the cells. Cultured cells were divided into 6 groups, No treatment control, LLLT only, GM 6.6 mM and GM 13.1 mM, GM 6.6 mM+LLLT and GM 13.1 mM+LLLT cells. LD laser 808 nm, 15 mW, was irradiated to the cultured cells for 15 min, at 4 hours after GM treatment to the cells. ATP was assayed using the ATP assay Kit. ROS was measured using confocal microscope after application of H2DCFDA dye. Results: ATP was decreased in GM 13.1 mM cells and increased in LLLT only cells and GM 13.1 mM+LLLT cells compared to control and 13.1 mM cells. ROS was increased in GM 6.6 mM and GM 13.1 mM cells, and decreased in GM 6.6 mM+LLLT and GM 13.1 mM+LLLT cells compared to GM 6.6 and 13.1 mM cells immediately after laser irradiation. Conclusion: This study demonstrated that LLLT on GM treated HEI-OC1 cells increased ATP and decreased ROS that may contribute to the recovery of hearing.

Rhee, ChungKu; Chang, So-Young; Ahn, Jin-Chul; Suh, Myung-Whan; Jung, Jae Yun

2014-03-01

328

The elevated blood pressure of human GRK4gamma A142V transgenic mice is not associated with increased ROS production.  

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G protein-coupled receptor (GPCR) kinases (GRKs) regulate the sensitivity of GPCRs, including dopamine receptors. The GRK4 locus is linked to, and some of its polymorphisms are associated with, human essential hypertension. Transgenic mice overexpressing human (h) GRK4gamma A142V on a mixed genetic background (C57BL/6J and SJL/J) have impaired renal D(1)-dopamine receptor (D(1)R) function and increased blood pressure. We now report that hGRK4gamma A142V transgenic mice, in C57BL/6J background, are hypertensive and have higher blood pressures than hGRK4gamma wild-type transgenic and nontransgenic mice. The hypertensive phenotype is stable because blood pressures in transgenic founders and F6 offspring are similarly increased. To determine whether the hypertension is associated with increased production of reactive oxygen species (ROS), we measured renal NADPH oxidase (Nox2 and Nox4) and heme oxygenase (HO-1 and HO-2) protein expressions and urinary excretion of 8-isoprostane and compared the effect of Tempol on blood pressure in hGRK4gamma A142V transgenic mice and D(5)R knockout (D(5)(-/-)) mice in which hypertension is mediated by increased ROS. The expressions of Nox isoforms and HO-2 and the urinary excretion of 8-isoprostane were similar in hGRK4gamma A142V transgenic mice and their controls. HO-1 expression was increased in hGRK4gamma A142V relative to hGRK4gamma wild-type transgenic mice. In contrast with the hypotensive effect of Tempol in D(5)(-/-) mice, it had no effect in hGRK4gamma A142V transgenic mice. We conclude that the elevated blood pressure of hGRK4gamma A142V transgenic mice is due mainly to the effect of hGRK4gamma A142V transgene acting via D(1)R and increased ROS production is not a contributor. PMID:17259440

Wang, Zheng; Armando, Ines; Asico, Laureano D; Escano, Crisanto; Wang, Xiaoyan; Lu, Quansheng; Felder, Robin A; Schnackenberg, Christine G; Sibley, David R; Eisner, Gilbert M; Jose, Pedro A

2007-05-01

329

Pro-metastatic signaling by c-Met through RAC-1 and reactive oxygen species (ROS)  

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Overexpression of the c-Met/hepatocyte growth factor receptor(HGF-R) proto-oncogene and abnormal generation of intracellular oxygen species (reactive oxygen species (ROS)) have been linked, by independent lines of evidence, to cell transformation and to malignant growth. By comparing two subpopulations of the B16 mouse melanoma (B16-F0 and B16-F10) endowed with different lung metastasis capacities (low and high, respectively) we found that both the expression/phosphorylation of c-Met and the ...

2006-01-01

330

Differential Ca2+-Sensor GCAPs Modes of Photoreceptor ROS-GC1 Signaling  

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Photoreceptor ROS-GC1 (Rod outer segment membrane guanylate cyclase) is a vital component of phototransduction. It is a bimodal Ca2+ signal transduction switch, operating between 20 nM to near 1000 nM range. Modulated by Ca2+ sensors GCAP1 and GCAP2, lowering of [Ca2+]i from 200 to 20 nM progressively turns it “ON”. Similarly, does the modulation by the Ca2+ sensor S100B, raising [Ca2+]i from 100 to 1000 nM. The GCAP-mode plays a vital role in phototransduction in both rods and cones; and...

Duda, Teresa; Pertzev, Alexandre; Sharma, Rameshwar K.

2012-01-01

331

?-Mangostin inhibits hypoxia-driven ROS-induced PSC activation and pancreatic cancer cell invasion.  

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Recent advances indicating a key role of microenvironment for tumor progression, we investigated the role of PSCs and hypoxia in pancreatic cancer aggressiveness, and examined the potential protective effect of ?-mangostin on hypoxia-driven pancreatic cancer progression. Our data indicate that hypoxic PSCs exploit their oxidative stress due to hypoxia to secrete soluble factors favouring pancreatic cancer invasion. ?-Mangostin suppresses hypoxia-induced PSC activation and pancreatic cancer cell invasion through the inhibition of HIF-1? stabilization and GLI1 expression. Increased generation of hypoxic ROS is responsible for HIF-1? stabilization and GLI1 upregulation. Therefore, ?-mangostin may be beneficial in preventing hypoxia-induced pancreatic cancer progression. PMID:24513179

Lei, Jianjun; Huo, Xiongwei; Duan, Wanxing; Xu, Qinhong; Li, Rong; Ma, Jiguang; Li, Xuqi; Han, Liang; Li, Wei; Sun, Hao; Wu, Erxi; Ma, Qingyong

2014-05-28

332

Chromosome 11 protects against DNA damage by reactive oxygen species (ROS)  

International Nuclear Information System (INIS)

Recent evidence suggests that chromosome 11 plays an important role in determining a cell's sensitivity to DNA damage by ROS. The induction of micronuclei (MN) by treatment with ROS was found to be reduced in a bladder carcinoma cell line (open-quotes parentclose quotes) when a normal chromosome 11 was inserted (open-quotes hybridclose quotes). These studies have been extended to include a third cell line (open-quotes revertantclose quotes) derived from the open-quotes hybridclose quotes by spontaneous loss of the chromosome (11) insert. In this study, MN induction and nuclear division indices (NDI) were determined in all 3 lines after exposure to either hydrogen peroxide (H_2O_2) (0-32.3 ?M) or to ?-radiation (0-3 Gy). For both agents, there was a significant protection against induction of MN in the hybrid cell line (p<0.0001). This protection was lost in the revertant line. There was significantly more protection against H_2O_2-induced damage than against damage by irradiation. At the highest dose for H_2O_2 (32.3?M), induced MN frequencies for hybrid cells (3.7%) were approximately 5-fold lower than frequencies in the parent (17.1%) or revertant (18.6%) cells. In contrast, after 1 Gy of irradiation, induced MN frequencies in hybrid cells (18.7%) were 1.4-fold less than either the parent (26.2%) or revertant (27.6%) cells (ratio at 3 Gy was 1.4-fold also). The 2 treatments also had a different effect on the NDI (an index of toxicity and/or growth inhibition). Both treatments induced a decrease in NDI. The chromosome 11 insert protected hybrid cells from this effect but only after exposure to H_2O_2 and not to irradiation. These data suggest a protective effect against ROS. Since only a portion of DNA damage from ?-ray treatment is due to ROS, this may account for the reduced ability of the chromosome 11 to provide a protective effect against DNA damage due to ?-ray exposure

1994-05-07

333

The involvement of TLR2 in cytokine and reactive oxygen species (ROS) production by PBMCs in response to Leishmania major phosphoglycans (PGs).  

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In the present study, we show for the first time that lipophosphoglycan (LPG) stimulated cytokine production by human peripheral blood mononuclear cells is also mediated via Toll-like receptor (TLR2). In addition, in order to verify if TLR2 is involved in recognition of the purified PGs, neutralizing mAbs against TLR2 and TLR4 were used to treat the cells before being stimulated with PGs. We found strong Th1-promoting cytokines induced by sLPG but not by mLPG which was blocked by presence of anti-TLR2 mAb. This finding reveals a mechanism by which the first encounter and recognition of L. major promastigotes by mLPG after interaction with TLR2 provides a cytokine milieu for consequent Th2 differentiation. Moreover, having shown the strong induction of Th1-promoting cytokines and low production of IL-10 in response to sLPG might have vaccine implication since it is recognized by TLR2 providing signals to professional antigen presenting cells that reside in the skin to promote effective T cell responses against Leishmania infection. In addition, it was shown that purified mLPG and sLPG activate reactive oxygen species (ROS) production which is also blocked by anti-TLR2 but not by anti-TLR4. However, no inhibition was seen in PPG-induced cytokine and ROS production in the presence of anti-TLR2 and anti-TLR4, implying involvement of other receptors. PMID:19631014

Kavoosi, G; Ardestani, S K; Kariminia, A

2009-09-01

334

Phosphorylated I?B? predicts poor prognosis in activated B-cell lymphoma and its inhibition with thymoquinone induces apoptosis via ROS release.  

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Activated B-cell lymphoma (ABC), one of the three subtypes of Diffuse Large B-cell Lymphoma (DLBCL) has the worst survival rate after upfront chemotherapy and is characterized by constitutively activated NF?B. We therefore studied the role of NF?B In a cohort of clinical DLBCL samples and ABC cell lines. In our clinical tissue microarray cohort of DLBCL samples, p-I?B? was detected in 38.3% of ABC DLBCL and was an independent prognostic marker for poor survival. In vitro, we found that Thymoquinone (TQ), a natural compound isolated from Nigella sativa caused release of ROS in ABC cells. TQ-mediated release of ROS in turn inhibited NF?B activity by dephosphorylating I?B? and decreased translocation of p65 subunit of NF?B in the nuclear compartment in ABC cell lines. This led to inhibition of cell viability and induction of mitochondrial dependent apoptosis in ABC-DLBCL cell lines. Additionally, TQ treatment also caused up-regulation of death receptor 5 (DR5), however, up-regulation of DR5 did not play a role in TQ-induced apoptosis. Finally, combination of sub-optimal doses of TQ and TRAIL induced efficient apoptosis in ABC-DLBCL cell lines. These data show that p-I?B? can be used as a prognostic marker and target for therapy in this aggressive sub-type of DLBCL and TQ may play an important role in the management of DLBCL in the future. PMID:23555990

Hussain, Azhar R; Uddin, Shahab; Ahmed, Maqbool; Al-Dayel, Fouad; Bavi, Prashant P; Al-Kuraya, Khawla S

2013-01-01

335

Cytotoxic mechanisms of Zn{sup 2+} and Cd{sup 2+} involve Na{sup +}/H{sup +} exchanger (NHE) activation by ROS  

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The signaling mechanism induced by cadmium (Cd) and zinc (Zn) in gill cells of Mytilus galloprovincialis was investigated. Both metals cause an increase in {center_dot}O{sub 2} {sup -} production, with Cd to be more potent (216 {+-} 15%) than Zn (150 {+-} 9.5%), in relation to control value (100%). The metals effect was reversed after incubation with the amiloride analogue, EIPA, a selective Na{sup +}/H{sup +} exchanger (NHE) inhibitor as well as in the presence of calphostin C, a protein kinase C (PKC) inhibitor. The heavy metals effect on {center_dot}O{sub 2} {sup -} production was mediated via the interaction of metal ions with {alpha}{sub 1}- and {beta}-adrenergic receptors, as shown after incubation with their respective agonists and antagonists. In addition, both metals caused an increase in intracellular pH (pHi) of gill cells. EIPA together with either metal significantly reduced the effect of each metal treatment on pHi. Incubation of gill cells with the oxidants rotenone, antimycin A and pyruvate caused a significant increase in pHi ({delta}pHi 0.830, 0.272 and 0.610, respectively), while in the presence of the anti-oxidant N-acetyl cysteine (NAC) a decrease in pHi ({delta}pHi -0.090) was measured, indicating that change in reactive oxygen species (ROS) production by heavy metals affects NHE activity. When rosiglitazone was incubated together with either heavy metal a decrease in O{sub 2} {sup -} production was observed. Our results show a key role of NHE in the signal transduction pathway induced by Zn and Cd in gill cells, with the involvement of ROS, PKC, adrenergic and PPAR-{gamma} receptors. In addition, differences between the two metals concerning NHE activation, O{sub 2} {sup -} production and interaction with adrenergic receptors were observed.

Koutsogiannaki, Sophia [Laboratory of Animal Physiology, Zoology Department, School of Biology, Faculty of Science, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Evangelinos, Nikolaos [Laboratory of Animal Physiology, Zoology Department, School of Biology, Faculty of Science, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Koliakos, George [Department of Biological Chemistry, Medical School, Aristotle University of Thessaloniki, P.O. Box 17034, 54124 Thessaloniki (Greece); Kaloyianni, Martha [Laboratory of Animal Physiology, Zoology Department, School of Biology, Faculty of Science, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece)]. E-mail: kaloyian@bio.auth.gr

2006-07-20

336

Lipid peroxidation end product 4-hydroxy-trans-2-nonenal triggers unfolded protein response and heme oxygenase-1 expression in PC12 cells: Roles of ROS and MAPK pathways.  

Science.gov (United States)

This study investigates the roles of ROS overproduction and MAPK signaling pathways in the induction of unfolded protein response (UPR) and the expression of Phase II enzymes in response to 4-hydroxy-trans-2-nonenal (4-HNE) in a neuronal-like catecholaminergic PC12 cells. Our results showed that 4-HNE triggered three canonical pathways of UPR, namely IRE1-XBP1, PERK-eIF2?-ATF4 and ATF6, and induced the expression of UPR-targeted genes, GRP78, CHOP, TRB3, PUMA, and GADD34, as well as Phase II enzymes, HO-1 and GCLC. 4-HNE also induced apoptosis, intracellular calcium accumulation, caspase-3 activation, and G0/G1 cell cycle arrest, which was correlated with the increased expression of GADD45?. The addition of tiron, a cellular permeable superoxide scavenger, scavenged 4-HNE-mediated ROS formation, but did not alleviate cytotoxicity, or the expression of UPR-targeted genes or Phase II enzymes, indicating that ROS overproduction per se did not play a major role in 4-HNE-caused deleterious effects. HO-1 expression was attenuated by Nrf2 siRNA and chemical chaperone 4-phenylbutyrate (4-PBA), suggesting HO-1 expression was regulated by Nrf2-ARE, which may work downstream of ER stress. 4-HNE treatment promptly induced ERK, JNK and p38 MAPK activation. Addition of p38 MAPK specific inhibitor SB203580 attenuated HO-1 upregulation, but enhanced expression of CHOP, PUMA and TRB3, and cytotoxicity. These results indicate that 4-HNE-induced transient p38 MAPK activation may serve as an upstream negative regulator of ER stress and confer adaptive cytoprotection against 4-HNE-mediated cell injury. PMID:24291486

Lin, Meng-Han; Yen, Jui-Hung; Weng, Ching-Yi; Wang, Lisu; Ha, Choi-Lan; Wu, Ming-Jiuan

2014-01-01

337

Reactive oxygen species production and redox state in parthenogenetic and sperm-mediated bovine oocyte activation.  

Science.gov (United States)

The knowledge concerning redox and reactive oxygen species (ROS)-mediated regulation of early embryo development is scarce and remains controversial. The aim of this work was to determine ROS production and redox state during early in vitro embryo development in sperm-mediated and parthenogenetic activation of bovine oocytes. Sperm-mediated oocyte activation was carried out in IVF-modified synthetic oviductal fluid (mSOF) with frozen-thawed semen. Parthenogenetic activation was performed in TALP plus ionomycin and then in IVF-mSOF with 6-dimethylaminopurine plus cytochalasin B. Embryos were cultured in IVF-mSOF. ROS and redox state were determined at each 2-h interval (7-24?h from activation) by 2',7'-dichlorodihydrofluorescein diacetate and RedoxSensor Red CC-1 fluorochromes respectively. ROS levels and redox state differed between activated and non-activated oocytes (P<0.05 by ANOVA). In sperm-activated oocytes, an increase was observed between 15 and 19?h (P<0.05). Conversely, in parthenogenetically activated oocytes, we observed a decrease at 9?h (P<0.05). In sperm-activated oocytes, ROS fluctuated throughout the 24?h, presenting peaks around 7, 19, and 24?h (P<0.05), while in parthenogenetic activation, peaks were detected at 7, 11, and 17?h (P<0.05). In the present work, we found clear distinctive metabolic patterns between normal and parthenogenetic zygotes. Oxidative activity and ROS production are an integral part of bovine zygote behavior, and defining a temporal pattern of change may be linked with developmental competence. PMID:23630331

Morado, S; Cetica, P; Beconi, M; Thompson, J G; Dalvit, G

2013-05-01

338

A mitochondrial thioredoxin-sensitive mechanism regulates TGF-?-mediated gene expression associated with epithelial-mesenchymal transition.  

Science.gov (United States)

Transforming growth factor (TGF)-? is a pro-oncogenic cytokine that induces the epithelial-mesenchymal transition (EMT), a crucial event in tumor progression. During TGF-?-mediated EMT in NMuMG mouse mammary epithelial cells, we observed sustained increases in reactive oxygen species (ROS) levels in the cytoplasm and mitochondria with a concomitant decrease in mitochondrial membrane potential and intracellular glutathione levels. In pseudo ?0 cells, whose respiratory chain function was impaired, the increase in intracellular ROS levels was abrogated, suggesting an important role of mitochondrial activity as a trigger for TGF-?-stimulated ROS generation. In line with this, TGF-?-mediated expression of the EMT marker fibronectin was inhibited not only by chemicals that interfere with ROS signaling but also by exogenously expressed mitochondrial thioredoxin (TXN2) independent of Smad signaling. Of note, TGF-?-mediated induction of HMGA2, a central mediator of EMT and metastatic progression, was similarly impaired by TXN2 expression, revealing a novel mechanism involving a thiol oxidation reaction in mitochondria, which regulates TGF-?-mediated gene expression associated with EMT. PMID:24342608

Ishikawa, Fumihiro; Kaneko, Emi; Sugimoto, Tadashi; Ishijima, Takahiro; Wakamatsu, Masami; Yuasa, Aya; Sampei, Ruriko; Mori, Kazunori; Nose, Kiyoshi; Shibanuma, Motoko

2014-01-17

339

Light regulation of cGMP metabolism in toad rod outer segments (ROS) deduced from intact photoreceptor and cellfree kinetics  

International Nuclear Information System (INIS)

The rate of cGMP hydrolysis by phosphodiesterase (PDE) in intact ROS, monitored in dark-adapted isolated toad retina by the rate of 18O appearance in guanine nucleotide ?-phosphoryls, is 1/360th of that observed in disrupted ROS at a substrate concentration equivalent to the total [cGMP] in ROS. Low to moderate photic stimuli increase this cGMP hydrolytic rate up to 10-fold in intact ROS with little or no change in total [cGMP]. G-protein activation determined in intact ROS by the fraction of GDP labeled with 18O corresponds with light-related increases in cGMP flux. In contrast, relatively high intensities and extended illumination cause attenuation of maximal cGMP hydrolysis with proportionate reductions in total [cGMP]. From these observations combined with the effects of activated G-protein on kinetics and cGMP binding of ROS PDE the following model for light-regulation of cGMP metabolism was deduced: cGMP flux in intact ROS is severely restricted in the dark state because approximately 99% of the cGMP is bound to high affinity sites on the non-stimulated form of PDE. This constraint is relieved when activated G-protein converts the cGMP-binding form of PDE to a high K/sub m/ catalytic form. cGMP is then redistributed to a dynamic pool where it is available to PDE catalytic sites and lower affinity allosteric sites. The [cGMP] in the dynamic pool is maintained or further increased or decreased by modulating the activity of an apparently light-sensitive guanylyl cyclase

1987-05-01

340

Salen-manganese complexes: sophisticated tools for the analysis of intercellular ROS signaling pathways.  

Science.gov (United States)

Salen-manganese complexes, such as EUK-8 and EUK-134 are known as catalase mimetics with superoxide dismutase (SOD) and peroxidase mimetic activity. Here we show that the concentration-dependent use of salen-manganese complexes within the appropriate time window and with parallel control of signaling parameters allows complex interactions during intercellular induction of apoptosis to be studied. At very low concentrations, salen-manganese complexes can abrogate consumption reactions between HOCl and hydrogen peroxide, as well as NO and hydrogen peroxide, and thus the major signaling pathways are enhanced. At higher concentrations of the compounds, all major signaling pathways are inhibited, thereby the catalase mimetic activity of the compounds affects both hydrogen peroxide and peroxynitrite. The ratio between available hydrogen peroxide and salen-manganese complexes defines whether reactive oxygen species (ROS) effects are inhibited or apoptosis is induced by the compounds. The SOD mimetic activity of salen-manganese complexes seems to be insufficient to interfere with intercellular ROS signaling. PMID:21036710

Ophoven, Stefanie J; Bauer, Georg

2010-10-01

 
 
 
 
341

Weightlessness influences the cytoskeleton and ROS level in SH-SY5Y neuroblastoma cells  

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During Spaceflight the nerve system of astronauts was obviously influenced To investigate how gravity effects nerve system the SH-SY5Y neuroblastoma cells were taken as research object By utilizing clinostat and parabolic flight for the model of gravity changing the level of reactive oxygen species was assayed in different time under simulated microgravity the cytomorphology and cytoskeleton of SH-SY5Y neuroblastoma cells were also observed after parabolic flight and clinostat by the conventional and the confocal laser scanning microscope The data showed that ROS level was enhanced and the cytoskeleton was damaged which microfilaments and microtubules were highly disorganized the cell shape was deteriorated under simulated microgravity indicating the relativity between the ROS level fluctuating and cytoskeleton changing It illuminates signal transduction disturbed by oxidative stress also regulates the cytoskeleton changing in SH-SY5Y cells The results suggest the cytoskeleton which is the receptor for sensing gravity was also regulated by cellular redox state which clues on the complexity of cell for self-adjusting to gravity changing

Bo, Wang; Lina, Qu; Yingxian, Li; Qi, Li; Lei, Bi; Yinghui, Li

342

ROS effects on neurodegeneration in Alzheimer's disease and related disorders: on environmental stresses of ionizing radiation.  

Science.gov (United States)

Neurodegenerative processes associated with Alzheimer's disease are complex and involve many CNS tissue types, structures and biochemical processes. Factors believed involved in these processes are generation of Reactive Oxygen Species (ROS), associated inflammatory responses, and the bio-molecular and genetic damage they produce. Since oxidative processes are essential to energy production, and to other biological functions, such as cell signaling, the process is not one of risk exposure, as for cigarettes and cancer, but one where normal physiological processes operate out of normal ranges and without adequate control. Thus, it is necessary to study the ambiphilicity that allows the same molecule (e.g., beta amyloid) to behave in contradictory ways depending upon the physiological microenvironment. To determine ways to study this in human populations we review evidence on the effects of an exogenous generator of ROS, ionizing radiation, in major population events with radionuclides (e.g., Hiroshima and Nagasaki; Chernobyl Reactor accident; environmental contamination in Chelyabinsk (South Urals) where plutonium was produced, and in the nuclear weapons test area in Semipalatinsk, Kazakhstan). The age evolution, and traits, of neurodegenerative processes in human populations in these areas, may help us understand how IR affects the CNS. After reviewing human population evidence, we propose a model of neurodegeneration based upon the complexity of CNS functions. PMID:15975057

Manton, Kenneth G; Volovik, Serge; Kulminski, Alexander

2004-11-01

343

Mitigation of ROS insults by Streptomyces secondary metabolites in primary cortical neurons.  

Science.gov (United States)

Oxidative stress is a common point in neurodegenerative diseases, widely connected with mitochondrial dysfunction. In this study, we screened seven natural products from Streptomyces sources against hydrogen peroxide insult in primary cortical neurons, an oxidative stress in vitro model. We showed the ability of these compounds to inhibit neuronal cytotoxicity and to reduce ROS release after 12 h treatment. Among the tested compounds, the quinone anhydroexfoliamycin and the red pyrrole-type pigment undecylprodigiosin stand out. These two compounds displayed the most complete protection against oxidative stress with mitochondrial function improvement, ROS production inhibition, and increase of antioxidant enzyme levels, glutathione and catalase. Further investigations confirmed that anhydroexfoliamycin acts over the Nrf2-ARE pathway, as a Nrf2 nuclear translocation inductor, and is able to strongly inhibit the effect of the mitochondrial uncoupler FCCP over cytosolic Ca(2+), pointing to mitochondria as a cellular target for this molecule. In addition, both compounds were able to reduce caspase-3 activity induced by the apoptotic enhancer staurosporine, but undecylprodigiosin failed to inhibit FCCP effects and it did not act over the Nrf2 pathway as was the case for anhydroexfoliamycin. These results show that Streptomyces metabolites could be useful for the development of new drugs for prevention of neurodegenerative disorders such as Parkinson's and Alzheimer's diseases and cerebral ischemia. PMID:24219236

Leirós, Marta; Alonso, Eva; Sanchez, Jon A; Rateb, Mostafa E; Ebel, Rainer; Houssen, Wael E; Jaspars, Marcel; Alfonso, Amparo; Botana, Luis M

2014-01-15

344

Intermittent hypoxia-induced endothelial barrier dysfunction requires ROS-dependent MAP kinase activation.  

Science.gov (United States)

The objective of the present study was to determine the impact of simulated apnea with intermittent hypoxia (IH) on endothelial barrier function and assess the underlying mechanism(s). Experiments were performed on human lung microvascular endothelial cells exposed to IH-consisting alternating cycles of 1.5% O2 for 30s followed by 20% O2 for 5 min. IH decreased transendothelial electrical resistance (TEER) suggesting attenuated endothelial barrier function. The effect of IH on TEER was stimulus dependent and reversible after reoxygenation. IH-exposed cells exhibited stress fiber formation and redistribution of cortactin, vascular endothelial-cadherins, and zona occludens-1 junction proteins along with increased intercellular gaps at cell-cell boundaries. Extracellular signal-regulated kinase (ERK) and c-jun NH2-terminal kinase (JNK) were phosphorylated in IH-exposed cells. Inhibiting either ERK or JNK prevented the IH-induced decrease in TEER and the reorganization of the cytoskeleton and junction proteins. IH increased reactive oxygen species (ROS) levels, and manganese (III) tetrakis (1-methyl-4-pyridyl) porphyrin pentachloride, a membrane-permeable antioxidant, prevented ERK and JNK phosphorylation as well as IH-induced changes in endothelial barrier function. These results demonstrate that IH via ROS-dependent activation of MAP kinases leads to reorganization of cytoskeleton and junction proteins resulting in endothelial barrier dysfunction. PMID:24477234

Makarenko, Vladislav V; Usatyuk, Peter V; Yuan, Guoxiang; Lee, May M; Nanduri, Jayasri; Natarajan, Viswanathan; Kumar, Ganesh K; Prabhakar, Nanduri R

2014-04-01

345

Mitochondrial oxidant production by a pollutant dust and NO-mediated apoptosis in human alveolar macrophage.  

Science.gov (United States)

Residual oil fly ash (ROFA) is a pollutant dust that stimulates production of reactive oxygen species (ROS) from mitochondria and apoptosis in alveolar macrophages (AM), but the relationship between these two processes is unclear. In this study, human AM were incubated with ROFA or vanadyl sulfate (VOSO(4)), the major metal constituent in ROFA, with or without nitro-L-arginine methyl ester (L-NAME), diphenyleneiodonium (DPI), and mitochondrial electron transport inhibitors. Interactions among production of ROS, nitric oxide (NO), and apoptosis of AM were determined. ROFA-stimulated ROS production was attenuated by DPI, rotenone, antimycin, and NaN(3), but not by L-NAME, a pattern mimicked by VOSO(4). ROFA-induced apoptosis was inhibited by L-NAME and a caspase-3-like protease inhibitor, but not by mitochondrial inhibitors. ROFA enhanced NO-mediated increase in caspase-3-like activity. VOSO(4) had minor effects on apoptosis. Thus ROFA-stimulated production of ROS from mitochondria was independent of apoptosis of AM, which was mediated by activation of caspase-3-like proteases and NO. The pro-oxidant effect but not the proapoptotic effect of ROFA was mediated by vanadium. PMID:12388087

Huang, Yuh-Chin T; Soukup, Joleen; Harder, Shirley; Becker, Susanne

2003-01-01

346

?-Amyloid-evoked apoptotic cell death is mediated through MKK6-p66shc pathway.  

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We have previously shown the involvement of p66shc in mediating apoptosis. Here, we demonstrate the novel mechanism of ?-Amyloid-induced toxicity in the mammalian cells. ?-Amyloid leads to the phosphorylation of p66shc at the serine 36 residue and activates MKK6, by mediating the phosphorylation at serine 207 residue. Treatment of cells with antioxidants blocks ?-Amyloid-induced serine phosphorylation of MKK6, reactive oxygen species (ROS) generation, and hence protected cells against ?-Amyloid-induced cell death. Our results indicate that serine phosphorylation of p66shc is carried out by active MKK6. MKK6 knock-down resulted in decreased serine 36 phosphorylation of p66shc. Co-immunoprecipitation results demonstrate a direct physical association between p66shc and WT MKK6, but not with its mutants. Increase in ?-Amyloid-induced ROS production was observed in the presence of MKK6 and p66shc, when compared to triple mutant of MKK6 (inactive) and S36 mutant of p66shc. ROS scavengers and knock-down against p66shc, and MKK6 significantly decreased the endogenous level of active p66shc, ROS production, and cell death. Finally, we show that the MKK6-p66shc complex mediates ?-Amyloid-evoked apoptotic cell death. PMID:24085465

Bashir, Muneesa; Parray, Arif A; Baba, Rafia A; Bhat, Hina F; Bhat, Sehar S; Mushtaq, Umar; Andrabi, Khurshid I; Khanday, Firdous A

2014-03-01

347

Rod and cone photoreceptor cells produce ROS in response to stress in a live retinal explant system.  

LENUS (Irish Health Repository)

PURPOSE: The production of reactive oxygen species (ROS) can lead to oxidative stress, which is a strong contributory factor to many ocular diseases. In this study, the removal of trophic factors is used as a model system to investigate the effects of stress in the retina. The aims were to determine if both rod and cone photoreceptor cells produce ROS when they are deprived of trophic factor support and to demonstrate if the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (Nox) enzymes are responsible for this ROS production. METHODS: Retinas were explanted from mice aged between postnatal days 8-10 and cultured overnight. The following morning, confocal microscopy combined with various fluorescent probes was used to detect the production of ROS. Each time peanut agglutinin (PNA), a cone photoreceptor marker, was used to facilitate orientation of the retina. Dihydroethidium and dihydrorhodamine 123 (DHR123) were used to determine which cells produce ROS. Subsequently, western blots of retinal serial sections were used to detect the presence of Noxs in the different retinal layers. The Nox inhibitor apocynin was then tested to determine if it altered the production of ROS within these cells. RESULTS: Live retinal explants, viewed at high magnifications using confocal microscopy, displayed an increase in the fluorescent products of dihydroethidium and DHR123 upon serum removal when compared to controls. DHR123 fluorescence, once oxidized, localized to mitochondria and was found in the same focal plane as the PNA staining. This showed that cones and rods produced ROS when stressed. Retinal serial sectioning established that the photoreceptor layer expressed Nox4, dual oxidase (Duox) 1, and Duox2 at varying levels. Finally, the Nox inhibitor apocynin decreased the burst stimulated by the stress of serum removal. CONCLUSIONS: Confocal microscopy and PNA staining allowed differentiation of cell types within the outermost layers of the retina, demonstrating that both rods and cones generated ROS in response to the stress of serum deprivation. Nox4 was the most abundantly expressed Nox in the photoreceptor layer, but Duox1 and Duox2 were also present at detectable levels, and as apocynin reduced the levels of ROS produced, this implied that these proteins may play some role in this production.

Bhatt, Lavinia

2010-01-01

348

Changes in reactive oxygen species (ROS) production in rat brain during global perinatal asphyxia: an ESR study.  

Science.gov (United States)

A large body of evidence suggests that the production of reactive oxygen species (ROS) can play an important role in ischemic neuronal injury. However any studies has been performed in hypoxic conditions. In the present experiments we studied using electron spin resonance (ESR) techniques the ROS release in neostriatum of newborn rats subjected to acute perinatal asphyxia (PA) followed by various periods of reoxygenation. Pregnant rats' uteri still containing foetuses were taken out and subjected to PA by immersion in a 37 degrees C water bath during the following periods of time: 5, 10, 15, 19 and 20 min. After performing PA, animals were recovered and ROS measured after 0, 5, 15, 30 or 60 min of reoxygenation. Then, pups were sacrificed, their neostriatum removed and homogenised with N-tert.-butyl-alpha-phenylnitrone (PBN) and diethylenetriamine-pentacetic acid (DPTA) in phosphate-buffered saline (PBS) and the formed complexes were extracted with ethyl acetate an analysed using an X-band ESR spectrometer. A significant release of ROS was detected at 19 and 20 min of PA after 5 min of reoxygenation. These data provide strong evidence that ROS could be involved in neuronal damage during PA. PMID:11578613

Capani, F; Loidl, C F; Aguirre, F; Piehl, L; Facorro, G; Hager, A; De Paoli, T; Farach, H; Pecci-Saavedra, J

2001-09-28

349

Dynamic Modeling of Anode Function in Enzyme-Based Biofuel Cells Using High Mediator Concentration  

Directory of Open Access Journals (Sweden)

Full Text Available The working principle of enzyme-based biofuel cells (EBFCs is the same as that of conventional fuel cells. In an EBFC system, the electricity-production process is very intricate. Analysis requires a mathematical model that can adequately describe the EBFC and predict its performance. This paper develops a dynamic model simulating the discharge performance of the anode for which supported glucose oxidase and mediator immobilize in the EBFC. The dynamic transport behavior of substrate, redox state (ROS of enzyme, enzyme-substrate complex, and the mediator creates different potential changes inside the anode. The potential-step method illustrates the dynamic phenomena of substrate diffusion, ROS of enzyme, production of enzyme-substrate complex, and reduction of the mediator with different potential changes.

Der-Sheng Chan

2012-07-01

350

Vorinostat and sorafenib increase CD95 activation in gastrointestinal tumor cells through a Ca2+ - de novo ceramide - PP2A - ROS dependent signaling pathway  

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The targeted therapeutics sorafenib and vorinostat interact in a synergistic fashion to kill carcinoma cells by activating CD95, and this drug combination is entering phase I evaluation. In this study we determined how CD95 is activated by treatment with this drug combination. Low doses of sorafenib and vorinostat but not the individual drugs rapidly increased ROS, Ca2+ and ceramide levels in GI tumor cells. The production of ROS was reduced in Rho zero cells. Quenching ROS blocked drug-induc...

Park, Margaret A.; Mitchell, Clint; Zhang, Guo; Yacoub, Adly; Allegood, Jeremy; Ha?ussinger, Dieter; Reinehr, Roland; Larner, Andrew; Spiegel, Sarah; Fisher, Paul B.; Voelkel-johnson, Christina; Ogretmen, Besim; Grant, Steven; Dent, Paul

2010-01-01

351

Arrhythmogenic adverse effects of cardiac glycosides are mediated by redox modification of ryanodine receptors  

Science.gov (United States)

Abstract The therapeutic use of cardiac glycosides (CGs), agents commonly used in treating heart failure (HF), is limited by arrhythmic toxicity. The adverse effects of CGs have been attributed to excessive accumulation of intracellular Ca2+ resulting from inhibition of Na+/K+-ATPase ion transport activity. However, CGs are also known to increase intracellular reactive oxygen species (ROS), which could contribute to arrhythmogenesis through redox modification of cardiac ryanodine receptors (RyR2s). Here we sought to determine whether modification of RyR2s by ROS contributes to CG-dependent arrhythmogenesis and examine the relevant sources of ROS. In isolated rat ventricular myocytes, the CG digitoxin (DGT) increased the incidence of arrhythmogenic spontaneous Ca2+ waves, decreased the sarcoplasmic reticulum (SR) Ca2+ load, and increased both ROS and RyR2 thiol oxidation. Additionally, pretreatment with DGT increased spark frequency in permeabilized myocytes. These effects on Ca2+ waves and sparks were prevented by the antioxidant N-(2-mercaptopropionyl) glycine (MPG). The CG-dependent increases in ROS, RyR2 oxidation and arrhythmogenic propensity were reversed by inhibitors of NADPH oxidase, mitochondrial ATP-dependent K+ channels (mito-KATP) or permeability transition pore (PTP), but not by inhibition of xanthine oxidase. These results suggest that the arrhythmogenic adverse effects of CGs involve alterations in RyR2 function caused by oxidative changes in the channel structure by ROS. These CG-dependent effects probably involve release of ROS from mitochondria possibly mediated by NADPH oxidase.

Ho, Hsiang-Ting; Stevens, Sarah C W; Terentyeva, Radmila; Carnes, Cynthia A; Terentyev, Dmitry; Gyorke, Sandor

2011-01-01

352

Peroxisomal polyamine oxidase and NADPH-oxidase cross-talk for ROS homeostasis which affects respiration rate in Arabidopsis thaliana.  

Science.gov (United States)

Homeostasis of reactive oxygen species (ROS) in the intracellular compartments is of critical importance as ROS have been linked with nearly all cellular processes and more importantly with diseases and aging. PAs are nitrogenous molecules with an evolutionary conserved role in the regulation of metabolic and energetic status of cells. Recent evidence also suggests that polyamines (PA) are major regulators of ROS homeostasis. In Arabidopsis the backconversion of the PAs spermidine (Spd) and spermine to putrescine and Spd, respectively, is catalyzed by two peroxisomal PA oxidases (AtPAO). However, the physiological role of this pathway remains largely elusive. Here we explore the role of peroxisomal PA backconversion and in particular that catalyzed by the highly expressed AtPAO3 in the regulation of ROS homeostasis and mitochondrial respiratory burst. Exogenous PAs exert an NADPH-oxidase dependent stimulation of oxygen consumption, with Spd exerting the strongest effect. This increase is attenuated by treatment with the NADPH-oxidase blocker diphenyleneiodonium iodide (DPI). Loss-of-function of AtPAO3 gene results to increased NADPH-oxidase-dependent production of superoxide anions ([Formula: see text] ), but not H2O2, which activate the mitochondrial alternative oxidase pathway (AOX). On the contrary, overexpression of AtPAO3 results to an increased but balanced production of both H2O2 and [Formula: see text] . These results suggest that the ratio of [Formula: see text] /H2O2 regulates respiratory chain in mitochondria, with PA-dependent production of [Formula: see text] by NADPH-oxidase tilting the balance of electron transfer chain in favor of the AOX pathway. In addition, AtPAO3 seems to be an important component in the regulating module of ROS homeostasis, while a conserved role for PA backconversion and ROS across kingdoms is discussed. PMID:24765099

Andronis, Efthimios A; Moschou, Panagiotis N; Toumi, Imene; Roubelakis-Angelakis, Kalliopi A

2014-01-01

353

Endoplasmic reticulum stress triggers ROS signalling, changes the redox state, and regulates the antioxidant defence of Arabidopsis thaliana.  

Science.gov (United States)

Inefficient chaperone activity in endoplasmic reticulum (ER) causes accumulation of unfolded proteins and is called ER stress, which triggers the unfolded protein response. For proper oxidative protein folding, reactive oxygen species (ROS) such as H2O2 are produced in the ER. Although the role of ROS during abiotic stresses such as salinity is well documented, the role of ER-related ROS production and its signalling is not yet known. Moreover, how H2O2 production, redox regulation, and antioxidant defence are affected in salt-treated plants when ER protein-folding machinery is impaired needs to be elucidated. For this aim, changes in NADPH-oxidase-dependent ROS signalling and H2O2 content at sequential time intervals and after 48 h of ER stress, induced by tunicamycin (Tm), salinity, and their combination were determined in Arabidopsis thaliana. The main root growth was inhibited by ER stress, while low levels of Tm caused an increase in lateral root density. Salt stress and Tm induced the expression of ER-stress-related genes (bZIP17, bZIP28, bZIP60, TIN1, BiP1, BiP3) and ERO1. Tm induced expression of RBOHD and RBOHF, which led to an early increase in H2O2 and triggered ROS signalling. This study is the first report that ER stress induces the antioxidant system and the Asada-Halliwell pathway of A. thaliana in a similar way to salinity. ER stress caused oxidative damage, as evident by increased H2O2 accumulation, lipid peroxidation, and protein oxidation. As a result, this study shows that ER stress triggers ROS signalling, changes the redox state, and regulates the antioxidant defence of A. thaliana. PMID:24558072

Ozgur, Rengin; Turkan, Ismail; Uzilday, Baris; Sekmen, Askim H

2014-03-01

354

Mitochondria-Derived Reactive Intermediate Species Mediate Asbestos-Induced Genotoxicity and Oxidative Stress–Responsive Signaling Pathways  

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Background: The incidence of asbestos-induced human cancers is increasing worldwide, and considerable evidence suggests that reactive oxygen species (ROS) are important mediators of these diseases. Our previous studies suggested that mitochondria might be involved in the initiation of oxidative stress in asbestos-exposed mammalian cells.

Huang, Sarah X. L.; Partridge, Michael A.; Ghandhi, Shanaz A.; Davidson, Mercy M.; Amundson, Sally A.; Hei, Tom K.

2012-01-01

355

MST1 activation by curcumin mediates JNK activation, Foxo3a nuclear translocation and apoptosis in melanoma cells  

International Nuclear Information System (INIS)

Highlights: •Curcumin activates MST1 in melanoma cells. •MST1 mediates curcumin-induced apoptosis of melanoma cells. •ROS production is involved in curcumin-induced MST1 activation. •MST1 mediates curcumin-induced JNK activation in melanoma cells. •MST1 mediates curcumin-induced Foxo3a nuclear translocation and Bim expression. -- Abstract: Different groups including ours have shown that curcumin induces melanoma cell apoptosis, here we focused the role of mammalian Sterile 20-like kinase 1 (MST1) in it. We observed that curcumin activated MST1-dependent apoptosis in cultured melanoma cells. MST1 silencing by RNA interference (RNAi) suppressed curcumin-induced cell apoptosis, while MST1 over-expressing increased curcumin sensitivity. Meanwhile, curcumin induced reactive oxygen species (ROS) production in melanoma cells, and the ROS scavenger, N-acetyl-cysteine (NAC), almost blocked MST1 activation to suggest that ROS might be required for MST1 activation by curcumin. c-Jun N-terminal protein kinase (JNK) activation by curcumin was dependent on MST1, since MST1 inhibition by RNAi or NAC largely inhibited curcumin-induced JNK activation. Further, curcumin induced Foxo3 nuclear translocation and Bim-1 (Foxo3 target gene) expression in melanoma cells, such an effect by curcumin was inhibited by MST1 RNAi. In conclusion, we suggested that MST1 activation by curcumin mediates JNK activation, Foxo3a nuclear translocation and apoptosis in melanoma cells

2013-11-08

356

MST1 activation by curcumin mediates JNK activation, Foxo3a nuclear translocation and apoptosis in melanoma cells  

Energy Technology Data Exchange (ETDEWEB)

Highlights: •Curcumin activates MST1 in melanoma cells. •MST1 mediates curcumin-induced apoptosis of melanoma cells. •ROS production is involved in curcumin-induced MST1 activation. •MST1 mediates curcumin-induced JNK activation in melanoma cells. •MST1 mediates curcumin-induced Foxo3a nuclear translocation and Bim expression. -- Abstract: Different groups including ours have shown that curcumin induces melanoma cell apoptosis, here we focused the role of mammalian Sterile 20-like kinase 1 (MST1) in it. We observed that curcumin activated MST1-dependent apoptosis in cultured melanoma cells. MST1 silencing by RNA interference (RNAi) suppressed curcumin-induced cell apoptosis, while MST1 over-expressing increased curcumin sensitivity. Meanwhile, curcumin induced reactive oxygen species (ROS) production in melanoma cells, and the ROS scavenger, N-acetyl-cysteine (NAC), almost blocked MST1 activation to suggest that ROS might be required for MST1 activation by curcumin. c-Jun N-terminal protein kinase (JNK) activation by curcumin was dependent on MST1, since MST1 inhibition by RNAi or NAC largely inhibited curcumin-induced JNK activation. Further, curcumin induced Foxo3 nuclear translocation and Bim-1 (Foxo3 target gene) expression in melanoma cells, such an effect by curcumin was inhibited by MST1 RNAi. In conclusion, we suggested that MST1 activation by curcumin mediates JNK activation, Foxo3a nuclear translocation and apoptosis in melanoma cells.

Yu, Teng, E-mail: tengyu33@yahoo.com [Department of Dermatology, Shandong Ji-ning No. 1 People’s Hospital, Shandong Province 272011 (China); Ji, Jiang [Department of Dermatology, The Second Hospital Affiliated of Soochow University, SuZhou, Jiangsu Province 215000 (China); Guo, Yong-li [Department of Oncology, Shandong Ji-ning No. 1 People’s Hospital, Shandong Province 272011 (China)

2013-11-08

357

ROS1 5-methylcytosine DNA glycosylase is a slow-turnover catalyst that initiates DNA demethylation in a distributive fashion  

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Arabidopsis ROS1 belongs to a family of plant 5-methycytosine DNA glycosylases that initiate DNA demethylation through base excision. ROS1 displays the remarkable capacity to excise 5-meC, and to a lesser extent T, while retaining the ability to discriminate effectively against C and U. We found that replacement of the C5-methyl group by halogen substituents greatly decreased excision of the target base. Furthermore, 5-meC was excised more efficiently from mismatches, whereas excision of T on...

Ponferrada-mari?n, Mari?a Isabel; Rolda?n-arjona, Teresa; Ariza, Rafael R.

2009-01-01

358

8-bromo-7-methoxychrysin-induced apoptosis of hepatocellular carcinoma cells involves ROS and JNK  

Directory of Open Access Journals (Sweden)

Full Text Available AIM: To investigate whether the apoptotic activities of 8-bromo-7-methoxychrysin (BrMC involve reactive oxygen species (ROS generation and c-Jun N-terminal kinase (JNK activation in human hepatocellular carcinoma cells (HCC.METHODS: HepG2, Bel-7402 and L-02 cell lines were cultured in vitro and the apoptotic effects of BrMC were evaluated by flow cytometry (FCM after propidium iodide (PI staining, caspase-3 activity using enzyme-linked immunosorbent assay (ELISA, and DNA agarose gel electrophoresis. ROS production was evaluated by FCM after dichlorodihydrofluorescein diacetate (DCHF-DA probe labeling. The phosphorylation level of JNK and c-Jun protein was analyzed by Western blotting.RESULTS: FCM after PI staining showed a dose-dependent increase in the percentage of the sub-G1 cell population (P < 0.05, reaching 39.0% ± 2.8% of HepG2 cells after 48 h of treatment with BrMC at 10 ?mol/L. The potency of BrMC to HepG2 and Bel-7402 (32.1% ± 2.6% cells was found to be more effective than the lead compound, chrysin (16.2% ± 1.6% for HepG2 cells and 11.0% ± 1.3% for Bel-7402 cell at 40 ?mol/L and similar to 5-flurouracil (33.0% ± 2.1% for HepG2 cells and 29.3% ± 2.3% for Bel-7402 cells at 10 ?mol/L. BrMC had little effect on human embryo liver L-02 cells, with the percentage of sub-G1 cell population 5.4% ± 1.8%. Treatment of HepG2 cells with BrMC for 48 h also increased the levels of active caspase-3, in a concentration-dependent manner. z-DEVD-fmk, a caspase-3-specific inhibitor, prevented the activation of caspase-3. Treatment with BrMC at 10 ?mol/L for 48 h resulted in the formation of a DNA ladder. Treatment of cells with BrMC (10 ?mol/L increased mean fluorescence intensity of DCHF-DA in HepG2 cells from 7.2 ± 1.12 at 0 h to 79.8 ± 3.9 at 3 h and 89.7 ± 4.7 at 6 h. BrMC did not affect ROS generation in L-02 cells. BrMC treatment failed to induce cell death and caspase-3 activation in HepG2 cells pretreated with N-acetylcysteine (10 mmol/L. In addition, in HepG2 cells treated with BrMC (2.5, 5.0, 10.0 ?mol/L for 12 h, JNK activation was observed. Peak JNK activation occurred at 12 h post-treatment and this activation persisted for up to 24 h. The expression of phosphorylated JNK and c-Jun protein after 12 h with BrMC-treated cells was inhibited by N-acetylcysteine and SP600125 pre-treatment, but GW9662 had no effect. SP600125 substa