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1

Sodium selenite-induced apoptosis mediated by ROS attack in human osteosarcoma U2OS cells.  

UK PubMed Central (United Kingdom)

Sodium selenite (Na(2)SeO(3), SSE) is an inorganic Se compound that is widely used in cancer chemoprevention studies. SSE has been shown to have anti-proliferative effects on several types of human cancer cells, but its effect on osteosarcoma cells has thus far not been reported. In this study, the cytotoxic effect of SSE on osteosarcoma cells U2OS was investigated in vitro and found to be higher than on comparable non-cancer cell lines 293 and L6. Treatment with SSE decreased cell growth in a dose- and time-dependent manner and altered cellular morphology. SSE also inhibited cell viability by inducing apoptosis, as evidenced by the formation of apoptotic bodies, generation of reactive oxygen species (ROS), and accumulation of cells during the advanced phase of apoptosis. SSE-induced apoptosis correlated with the activation of CASP 3, downregulation of BCL-2, and upregulation of P53 and PTEN in U2OS cells. These results indicated that SSE induces apoptosis in U2OS cells mainly through an ROS-mediated caspase pathway. This is the first report to show a possible mechanism of the anti-proliferative effect of SSE for the prevention of osteosarcoma in cell culture models.

Chen XJ; Duan FD; Zhang HH; Xiong Y; Wang J

2012-01-01

2

Sodium selenite-induced apoptosis mediated by ROS attack in human osteosarcoma U2OS cells.  

Science.gov (United States)

Sodium selenite (Na(2)SeO(3), SSE) is an inorganic Se compound that is widely used in cancer chemoprevention studies. SSE has been shown to have anti-proliferative effects on several types of human cancer cells, but its effect on osteosarcoma cells has thus far not been reported. In this study, the cytotoxic effect of SSE on osteosarcoma cells U2OS was investigated in vitro and found to be higher than on comparable non-cancer cell lines 293 and L6. Treatment with SSE decreased cell growth in a dose- and time-dependent manner and altered cellular morphology. SSE also inhibited cell viability by inducing apoptosis, as evidenced by the formation of apoptotic bodies, generation of reactive oxygen species (ROS), and accumulation of cells during the advanced phase of apoptosis. SSE-induced apoptosis correlated with the activation of CASP 3, downregulation of BCL-2, and upregulation of P53 and PTEN in U2OS cells. These results indicated that SSE induces apoptosis in U2OS cells mainly through an ROS-mediated caspase pathway. This is the first report to show a possible mechanism of the anti-proliferative effect of SSE for the prevention of osteosarcoma in cell culture models. PMID:21826611

Chen, Xiao-Jia; Duan, Fei-Die; Zhang, Hui-Hua; Xiong, Yi; Wang, Jin

2011-08-09

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Impact of central and peripheral TRPV1 and ROS levels on proinflammatory mediators and nociceptive behavior  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Transient receptor potential vanilloid 1 (TRPV1) channels are important membrane sensors on peripheral nerve endings and on supportive non-neuronal synoviocytes in the knee joint. TRPV 1 ion channels respond with activation of calcium and sodium fluxes to pH, thermal, chemical, osmotic, mechanical and other stimuli abundant in inflamed joints. In the present study, the kaolin/carrageenan (k/c) induced knee joint arthritis model in rats, as well as primary and clonal human synoviocyte cultures were used to understand the reciprocal interactions between reactive nitroxidative species (ROS) and functional TRPV1 channels. ROS generation was monitored with ROS sensitive dyes using live cell imaging in vitro and in spinal tissue histology, as well as with measurement of ROS metabolites in culture media using HPLC. Results Functional responses in the experimental arthritis model, including increased nociceptive responses (thermal and mechanical hyperalgesia and allodynia), knee joint temperature reflecting local blood flow, and spinal cord ROS elevations were reduced by the ROS scavenger PBN after intraperitoneal pretreatment. Increases in TRPV1 and ROS, generated by synoviocytes in vitro, were reciprocally blocked by TRPV1 antagonists and the ROS scavenger. Further evidence is presented that synoviocyte responses to ROS and TRPV1 activation include increases in TNF? and COX-2, both measured as an indicator of the inflammation in vitro. Conclusions The results demonstrate that contributions of ROS to pronociceptive responses and neurogenic inflammation are mediated both centrally and peripherally. Responses are mediated by TRPV1 locally in the knee joint by synoviocytes, as well as by ROS-induced sensitization in the spinal cord. These findings and those of others reported in the literature indicate reciprocal interactions between TRPV1 and ROS play critical roles in the pathological and nociceptive responses active during arthritic inflammation.

Westlund Karin N; Kochukov Mikhail Y; Lu Ying; McNearney Terry A

2010-01-01

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ROS Mediates Radiation-Induced Differentiation in Human Lung Fibroblast  

International Nuclear Information System (INIS)

[en] One of the most common tumors worldwide is lung cancer and the number of patients with lung cancer received radiotherapy is increasing rapidly. Although radiotherapy may have lots of advantages, it can also induce serious adverse effects such as acute radiation pneumonitis and pulmonary fibrosis. Pulmonary fibrosis is characterized by excessive production of smooth muscle actin-alpha (a-SMA) and accumulation of extracellular matrix (ECM) such as collagen and fibronectin. There has been a great amount of research about fibrosis but the exact mechanism causing the reaction is not elucidated especially in radiation-induced fibrosis. Until now it has been known that several factors such as transforming growth factor (TGF-b), tumor necrosis factor (TNF), IL-6, platelet-derived growth factor (PDGF) and reactive oxygen species are related to fibrosis. It is also reported that reactive oxygen species (ROS) can be induced by radiation and can act as a second messenger in various signaling pathways. Therefore we focused on the role of ROS in radiation induced fibrosis. Here, we suggest that irradiation generate ROS mainly through NOX4, result in differentiation of lung fibroblast into myofibroblast

2009-01-01

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ROS Mediates Radiation-Induced Differentiation in Human Lung Fibroblast  

Energy Technology Data Exchange (ETDEWEB)

One of the most common tumors worldwide is lung cancer and the number of patients with lung cancer received radiotherapy is increasing rapidly. Although radiotherapy may have lots of advantages, it can also induce serious adverse effects such as acute radiation pneumonitis and pulmonary fibrosis. Pulmonary fibrosis is characterized by excessive production of smooth muscle actin-alpha (a-SMA) and accumulation of extracellular matrix (ECM) such as collagen and fibronectin. There has been a great amount of research about fibrosis but the exact mechanism causing the reaction is not elucidated especially in radiation-induced fibrosis. Until now it has been known that several factors such as transforming growth factor (TGF-b), tumor necrosis factor (TNF), IL-6, platelet-derived growth factor (PDGF) and reactive oxygen species are related to fibrosis. It is also reported that reactive oxygen species (ROS) can be induced by radiation and can act as a second messenger in various signaling pathways. Therefore we focused on the role of ROS in radiation induced fibrosis. Here, we suggest that irradiation generate ROS mainly through NOX4, result in differentiation of lung fibroblast into myofibroblast.

Park, Sa Rah; Ahn, Ji Yeon; Kim, Mi Hyeung; Lim, Min Jin; Yun, Yeon Sook; Song, Jie Young [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)

2009-05-15

6

C-phycocyanin modulates selenite-induced cataractogenesis in rats.  

Science.gov (United States)

The present investigation is aimed to evaluate the anticataractogenic potential of C-phycocyanin (C-PC), extracted and purified from Spirulina platensis. Enucleated rat lenses were maintained in vitro in Dulbecco's modified Eagle medium (DMEM). Group I contained DMEM, Group II and Group III contained 100 ?M of sodium selenite, Group III was subdivided into three viz IIIa, IIIb, IIIc supplemented with 100, 150, 200 ?g of C-PC respectively. In the in vivo study, on tenth day post partum: Group I rat pups received an intraperitoneal injection of saline, Group II, IIIa, IIIb, and IIIc rat pups received a subcutaneous injection of sodium selenite (19 ?mol/kg bodyweight) Group IIIa, IIIb, IIIc also received an intraperitoneal injection of 100, 150, 200 mg/kg body weight of C-PC, respectively, from postpartum days?9-14. On termination of the experiment, the lenses from both in vitro and in vivo studies were subjected to morphological examination and subsequently processed to estimate the activities of antioxidant enzymes namely superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, levels of reduced glutathione and lipid peroxidation products. Sodium selenite-exposed, C-PC-treated rat lenses (Group IIIc), showed significant restoration of antioxidant enzyme activity (p?selenite-induced cataract incidence both in vitro and in vivo. PMID:23086307

Kumari, Rasiah Pratheepa; Sivakumar, Jeyarajan; Thankappan, Bency; Anbarasu, Kumarasamy

2012-10-20

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PTEN-regulated AKT/FoxO3a/Bim signaling contributes to reactive oxygen species-mediated apoptosis in selenite-treated colorectal cancer cells.  

UK PubMed Central (United Kingdom)

Mounting evidence shows that selenium possesses chemotherapeutic potential against tumor cells, including leukemia, prostate cancer and colorectal cancer (CRC) cells. However, the detailed mechanism by which sodium selenite specifically kills tumor cells remains unclear. Herein, we demonstrated that supranutritional doses of selenite-induced apoptosis in CRC cells through reactive oxygen species (ROS)-dependent modulation of the PI3K/AKT/FoxO3a signaling pathway. First, we found that selenite treatment in HCT116 and SW480 CRC cells caused inhibition of AKT and the nuclear accumulation of FoxO3a by western blot and immunofluorescence analyses, respectively, thereby facilitating transcription of the target genes bim and PTEN. Modulation of the AKT/FoxO3a/Bim signaling pathway by chemical inhibitors or RNA interference revealed that these events were critical for selenite-induced apoptosis in CRC cells. Additionally, we discovered that FoxO3a-mediated upregulation of PTEN exerted a further inhibitory effect on the AKT survival pathway. We also corroborated our findings in vivo by performing immunohistochemistry experiments. In summary, our results show that selenite could induce ROS-dependent FoxO3a-mediated apoptosis in CRC cells and xenograft tumors through PTEN-mediated inhibition of the PI3K/AKT survival axis. These results help to elucidate the molecular mechanisms underlying selenite-induced cell death in tumor cells and provide a theoretical basis for translational applications of selenium.

Luo H; Yang Y; Duan J; Wu P; Jiang Q; Xu C

2013-01-01

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Preventive effect of onion juice on selenite-induced experimental cataract  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 (3...

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

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The anorexigenic effect of serotonin is mediated by the generation of NADPH oxidase-dependent ROS.  

UK PubMed Central (United Kingdom)

Serotonin (5-HT) is a central inhibitor of food intake in mammals. Thus far, the intracellular mechanisms for the effect of serotonin on appetite regulation remain unclear. It has been recently demonstrated that reactive oxygen species (ROS) in the hypothalamus are a crucial integrative target for the regulation of food intake. To investigate the role of ROS in the serotonin-induced anorexigenic effects, conscious mice were treated with 5-HT alone or combination with Trolox (a ROS scavenger) or Apocynin (an NADPH oxidase inhibitor) by acute intracerebroventricular injection. Both Trolox and Apocynin reversed the anorexigenic action of 5-HT and the 5-HT-induced hypothalamic ROS elevation. The mRNA and protein expression levels of pro-opiomelanocortin (POMC) were dramatically increased after ICV injection with 5-HT. The anorexigenic action of 5-HT was accompanied by markedly elevated hypothalamic MDA levels and GSH-Px activity, while the SOD activity was decreased. Moreover, 5-HT significantly increased the mRNA expression of UCP-2 but reduced the levels of UCP-3. Both Trolox and Apocynin could block the 5-HT-induced changes in UCP-2 and UCP-3 gene expression. Our study demonstrates for the first time that the anorexigenic effect of 5-HT is mediated by the generation of ROS in the hypothalamus through an NADPH oxidase-dependent pathway.

Fang XL; Shu G; Yu JJ; Wang LN; Yang J; Zeng QJ; Cheng X; Zhang ZQ; Wang SB; Gao P; Zhu XT; Xi QY; Zhang YL; Jiang QY

2013-01-01

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

UK PubMed Central (United Kingdom)

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.

Lee MG; Lee KT; Chi SG; Park JH

2001-03-01

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

Science.gov (United States)

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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Resveratrol induces premature senescence in lung cancer cells via ROS-mediated DNA damage.  

UK PubMed Central (United Kingdom)

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 in the expression of cleaved PARP and activated caspase-3, suggesting that low dose RV treatment may suppress tumor cell growth via an apoptosis-independent mechanism. Subsequent studies reveal that low dose RV treatment induces a significant increase in senescence-associated ?-galactosidase (SA-?-gal) staining and elevated expression of p53 and p21 in NSCLC cells. Furthermore, we show that RV-induced suppression of lung cancer cell growth is associated with a decrease in the expression of EF1A. These results suggest that RV may exert its anticancer and chemopreventive effects through the induction of premature senescence. Mechanistically, RV-induced premature senescence correlates with increased DNA double strand breaks (DSBs) and reactive oxygen species (ROS) production in lung cancer cells. Inhibition of ROS production by N-acetylcysteine (NAC) attenuates RV-induced DNA DSBs and premature senescence. Furthermore, we show that RV treatment markedly induces NAPDH oxidase-5 (Nox5) expression in both A549 and H460 cells, suggesting that RV may increase ROS generation in lung cancer cells through upregulating Nox5 expression. Together, these findings demonstrate that low dose RV treatment inhibits lung cancer cell growth via a previously unappreciated mechanism, namely the induction of premature senescence through ROS-mediated DNA damage.

Luo H; Yang A; Schulte BA; Wargovich MJ; Wang GY

2013-01-01

13

Effect of electroacupuncture to prevent selenite-induced cataract in Wistar rats.  

UK PubMed Central (United Kingdom)

PURPOSE: To investigate whether electroacupuncture can prevent selenite-induced cataract in an experimental model. METHODS: Fifty Wistar rat pups were randomized into 5 groups of 10 animals: Group 1 (control), no procedure was performed; Group 2 (selenite), sodium selenite (30 micromoles/kg body weight) was injected subcutaneously between postpartum days 10 to 12; Group 3 (anesthesia) received the same dose of selenite and underwent ether inhalation anesthesia during 10 minutes daily for one week; Group 4 (electroacupuncture) underwent the same procedure of Group 3, but also receiving electroacupuncture (2 Hz, 50 mA) applied to the Neiguan (PC6) and Guangming (GB37) acupoints during the anesthesia period; and Group 5 (Sham) underwent the same procedures of Group 4, but needles were applied to non-acupoints. The development of cataract was assessed one week later, and its density was graded by slit lamp biomicroscopy. RESULTS: All control rats' lenses (Group 1) were clear. Groups 2, 3 and 5 rats developed more severe cataract or complete opacification. In Group 4 (electroacupuncture), 45% of eyes did not develop cataract while thirty per cent developed less severe cataract than Groups 2, 3 and 5. The between-group difference was statistically significant (p<0.001). Lens opacification grade in Groups 1 and 4 was lower than in the Groups 2, 3 and 5 (p<0.001). CONCLUSION: Electroacupuncture effectively decreased selenite-induced cataract formation rate in pup rats when needles were applied at specific acupoints.

Cariello AJ; Casanova FH; Lima Filho AA; Juliano Y; Tabosa A

2006-05-01

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ROS and Sympathetically Mediated Mitochondria Activation in Brown Adipose Tissue Contribute to Methamphetamine-Induced Hyperthermia.  

UK PubMed Central (United Kingdom)

Methamphetamine (Meth) 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 0.5°C and reduced the length of hyperthermia by 1?h, 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 uncoupling protein 1 upregulation. Furthermore, in isolated BAT cells in culture, Meth, but not Norepinephrine, 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.

Sanchez-Alavez M; Conti B; Wood MR; Bortell N; Bustamante E; Saez E; Fox HS; Marcondes MC

2013-01-01

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Gambogic Acid Sensitizes Ovarian Cancer Cells to Doxorubicin Through ROS-Mediated Apoptosis.  

UK PubMed Central (United Kingdom)

Ovarian cancer is one human malignancy which has response portly to doxorubicin. The anti-cancer activity of gambogic acid has been tested in in vitro and in vivo studies. In this study, we showed that gambogic acid, a natural compound, could potentiate the anticancer activity of doxorubicin in ovarian cancer through ROS-mediated apoptosis. Platinum-resistant human ovarian cancer cell line (SKOV-3) was treated with gambogic acid, doxorubicin, or the combination of both to investigate cell proliferation and apoptosis. We found that the combination of gambogic acid and doxorubicin causes synergistic loss of cell viability in SKOV-3 cells and this synergistic effect correlated with increased cellular ROS accumulation. Moreover, in vivo results showed that gambogic acid and doxorubicin combination resulted in a synergistic suppressing effect on tumor growth in ovarian cancer mice model. Taken together, the results suggested that doxorubicin in combination with gambogic acid might provide a promising therapeutic strategy to enhance chemosensitivity of ovarian cancer to doxorubicin.

Wang J; Yuan Z

2013-09-01

16

Preventive effect of onion juice on selenite-induced experimental cataract  

Science.gov (United States)

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; Ghorbanihaghjo, Amir; Bonyadi, Somayeh; Rashidi, Mohammad Reza; Mesgari, Mehran; Rashtchizadeh, Nadereh; Argani, Hassan

2009-01-01

17

Preventive effect of onion juice on selenite-induced experimental cataract.  

UK PubMed Central (United Kingdom)

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 A; Ghorbanihaghjo A; Bonyadi S; Rashidi MR; Mesgari M; Rashtchizadeh N; Argani H

2009-05-01

18

Preventive effect of onion juice on selenite-induced experimental cataract  

Directory of Open Access Journals (Sweden)

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

2009-01-01

19

Early ROS-mediated DNA damage and oxidative stress biomarkers in Monoclonal B Lymphocytosis.  

UK PubMed Central (United Kingdom)

Monoclonal B Lymphocytosis (MBL) is defined as asymptomatic monoclonal B-cell expansion characterised by a CLL-phenotype, but with less than 5×10(9)/l circulating cells. Reactive oxygen species (ROS)-mediated cell damage plays a critical role in the initiation of carcinogenesis as well as in malignant transformation. The goal of this study was to perform an analysis of the oxidative stress statuses of patients affected by MBL and chronic lymphocytic leukaemia (CLL). We examined peripheral blood and urine specimens from 29 patients with MBL, 55 with CLL and 31 healthy subjects. There was a significant increase in the occurrence of the mutagenic base 8-oxo-2'-deoxiguanosine (8-oxo-dG) in the lymphocytes and urine of MBL and CLL patients compared with controls. Significant differences were also observed in the levels of the lipid peroxidation product malondialdehyde (MDA) and in the oxidised/reduced glutathione (GSSG/GSH) ratio, although an increase in 8-isoprostane was not detected. Interestingly, the antioxidant catalase activity of circulating lymphocytes decreased in the patient groups. In conclusion, early oxidative stress exists in patients with MBL and CLL, causing damage to DNA and lipid structures. The higher levels of 8-oxo-dG in lymphocytes than in urine may be related to a decrease in the capacity of DNA repair systems. There were no differences in the oxidative statuses of the MBL and CLL patients, suggesting that oxidative injuries appear during a pre-leukaemic state of the disease.

Collado R; Oliver I; Tormos C; Egea M; Miguel A; Cerdá C; Ivars D; Borrego S; Carbonell F; Sáez GT

2012-04-01

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Mefloquine exerts anticancer activity in prostate cancer cells via ROS-mediated modulation of Akt, ERK, JNK and AMPK signaling.  

UK PubMed Central (United Kingdom)

Mefloquine (MQ) is a prophylactic anti-malarial drug. Previous studies have shown that MQ induces oxidative stress in vitro. Evidence indicates that reactive oxygen species (ROS) may be used as a therapeutic modality to kill cancer cells. This study investigated whether MQ also inhibits prostate cancer (PCa) cell growth. We used sulforhodamine B (SRB) staining to determine cell viability. MQ has a highly selective cytotoxicity that inhibits PCa cell growth. The antitumor effect was most significant when examined using a colony formation assay. MQ also induces hyperpolarization of the mitochondrial membrane potential (MMP), as well as ROS generation. The blockade of MQ-induced anticancer effects by N-acetyl cysteine (NAC) pre-treatment confirmed the role of ROS. This indicates that the MQ-induced anticancer effects are caused primarily by increased ROS generation. Moreover, we observed that MQ-mediated ROS simultaneously downregulated Akt phosphorylation and activated extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK) and adenosine monophosphate-activated protein kinase (AMPK) signaling in PC3 cells. These findings provide insights for further anticancer therapeutic options.

Yan KH; Yao CJ; Hsiao CH; Lin KH; Lin YW; Wen YC; Liu CC; Yan MD; Chuang SE; Lai GM; Lee LM

2013-05-01

 
 
 
 
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Mefloquine exerts anticancer activity in prostate cancer cells via ROS-mediated modulation of Akt, ERK, JNK and AMPK signaling.  

Science.gov (United States)

Mefloquine (MQ) is a prophylactic anti-malarial drug. Previous studies have shown that MQ induces oxidative stress in vitro. Evidence indicates that reactive oxygen species (ROS) may be used as a therapeutic modality to kill cancer cells. This study investigated whether MQ also inhibits prostate cancer (PCa) cell growth. We used sulforhodamine B (SRB) staining to determine cell viability. MQ has a highly selective cytotoxicity that inhibits PCa cell growth. The antitumor effect was most significant when examined using a colony formation assay. MQ also induces hyperpolarization of the mitochondrial membrane potential (MMP), as well as ROS generation. The blockade of MQ-induced anticancer effects by N-acetyl cysteine (NAC) pre-treatment confirmed the role of ROS. This indicates that the MQ-induced anticancer effects are caused primarily by increased ROS generation. Moreover, we observed that MQ-mediated ROS simultaneously downregulated Akt phosphorylation and activated extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK) and adenosine monophosphate-activated protein kinase (AMPK) signaling in PC3 cells. These findings provide insights for further anticancer therapeutic options. PMID:23760395

Yan, Kun-Huang; Yao, Chih-Jung; Hsiao, Chi-Hao; Lin, Ke-Hsun; Lin, Yung-Wei; Wen, Yu-Ching; Liu, Chung-Chi; Yan, Ming-DE; Chuang, Shuang-En; Lai, Gi-Ming; Lee, Liang-Ming

2013-02-22

22

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

DEFF Research Database (Denmark)

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-1ß induces divalent metal transporter 1 (DMT1) expression correlating with increased ß 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, ß 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

23

SIGNALLING PATHWAY OF NADPH MEDIATED ROS-RNS IN DIABETIC NEPHROPATHY  

Directory of Open Access Journals (Sweden)

Full Text Available Disorder of physiological signaling functions of reactive oxygen species (ROS) superoxide (ROS are chemically reactive molecules containing oxygen), hydrogen peroxide, reactive nitrogen species (RNS) nitric oxide and peroxynitrite are an important feature of diabetes mellitus. The balance between the production of ROS, notably superoxide anion (O?2) and hydrogen peroxide (H2O2), and the antioxidant defense system that includes superoxide dismutase (SOD) and peroxidases, determines the degree of oxidative stress. An increased production and/or decreased metabolism of ROS have been implicated in the pathogenesis of renal injury in diabetes mellitus (DM). Thus the regulation of ROS generation in diabetes by antioxidants seems to be a promising target for management of Diabetic nephropathy.

Tarar S.K.; Arora M.K.; Singh U.K.

2012-01-01

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Nitric oxide (NO) counteracts cadmium induced cytotoxic processes mediated by reactive oxygen species (ROS) in Brassica juncea: cross-talk between ROS, NO and antioxidant responses.  

UK PubMed Central (United Kingdom)

Research on NO in plants has achieved huge attention in recent years mainly due to its function in plant growth and development under biotic and abiotic stresses. In the present study, we investigated Cd induced NO generation and its relationship to ROS and antioxidant regulation in Brassica juncea. Cd accumulated rapidly in roots and caused oxidative stress as indicated by increased level of lipid peroxidation and H2O2 thus, inhibiting the overall plant growth. It significantly decreased the root length, leaf water content and photosynthetic pigments. A rapid induction in intracellular NO was observed at initial exposures and low concentrations of Cd. A 2.74-fold increase in intracellular NO was recorded in roots treated with 25 ?M Cd than control. NO effects on Malondialdehyde (MDA) content and on antioxidant system was investigated by using sodium nitroprusside (SNP), a NO donor and a scavenger, [2-(4-carboxy-2-phenyl)-4,4,5,5-tetramethylinidazoline-1-oxyl-3-oxide] (cPTIO). Roots pretreated with 5 mM SNP for 6 h when exposed to 25 ?M Cd for 24 h reduced the level of proline, non-protein thiols, SOD, APX and CAT in comparison to only Cd treatments. However, this effect was almost blocked by 100 ?M cPTIO pretreatment to roots for 1 h. This ameliorating effect of NO was specific because cPTIO completely reversed the effect in the presence of Cd. Thus, the present study report that NO strongly counteracts Cd induced ROS mediated cytotoxicity in B. juncea by controlling antioxidant metabolism as the related studies are not well reported in this species.

Verma K; Mehta SK; Shekhawat GS

2013-04-01

25

Nitric oxide (NO) counteracts cadmium induced cytotoxic processes mediated by reactive oxygen species (ROS) in Brassica juncea: cross-talk between ROS, NO and antioxidant responses.  

Science.gov (United States)

Research on NO in plants has achieved huge attention in recent years mainly due to its function in plant growth and development under biotic and abiotic stresses. In the present study, we investigated Cd induced NO generation and its relationship to ROS and antioxidant regulation in Brassica juncea. Cd accumulated rapidly in roots and caused oxidative stress as indicated by increased level of lipid peroxidation and H2O2 thus, inhibiting the overall plant growth. It significantly decreased the root length, leaf water content and photosynthetic pigments. A rapid induction in intracellular NO was observed at initial exposures and low concentrations of Cd. A 2.74-fold increase in intracellular NO was recorded in roots treated with 25 ?M Cd than control. NO effects on Malondialdehyde (MDA) content and on antioxidant system was investigated by using sodium nitroprusside (SNP), a NO donor and a scavenger, [2-(4-carboxy-2-phenyl)-4,4,5,5-tetramethylinidazoline-1-oxyl-3-oxide] (cPTIO). Roots pretreated with 5 mM SNP for 6 h when exposed to 25 ?M Cd for 24 h reduced the level of proline, non-protein thiols, SOD, APX and CAT in comparison to only Cd treatments. However, this effect was almost blocked by 100 ?M cPTIO pretreatment to roots for 1 h. This ameliorating effect of NO was specific because cPTIO completely reversed the effect in the presence of Cd. Thus, the present study report that NO strongly counteracts Cd induced ROS mediated cytotoxicity in B. juncea by controlling antioxidant metabolism as the related studies are not well reported in this species. PMID:23322177

Verma, Kusum; Mehta, S K; Shekhawat, G S

2013-01-16

26

Role of ROS and auxin in plant response to metal-mediated stress.  

UK PubMed Central (United Kingdom)

Being unable to move away from their places of germination, in order to avoid excess metal-induced damages, plants have to evolve different strategies and complex regulatory mechanisms to survive harsh conditions. While both ROS and auxin are documented to be important in plant response to metal stress, the mechanisms underlying the crosstalk between ROS and auxin in metal stress are poorly understood. In this review, we provide an update on the regulation of plant responses to metal-stress by ROS and auxin signaling pathways, primarily, with a focus on the copper, aluminum and cadmium stress. We aim at surveying the mechanisms underlying how metal stress modulates the changes in auxin distribution and the network of ROS and auxin in plant response to metal stress based on recent studies.

Yuan HM; Liu WC; Jin Y; Lu YT

2013-04-01

27

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

Directory of Open Access Journals (Sweden)

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(P)H 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

2006-01-01

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Stevioside induced ROS-mediated apoptosis through mitochondrial pathway in human breast cancer cell line MCF-7.  

UK PubMed Central (United Kingdom)

Stevioside is a diterpene glycoside found in the leaf of Stevia rebaudiana, a traditional oriental medicinal herb, which has been shown to have various biological and ethno-medicinal activities including antitumor activity. In this study, we investigated the effects of stevioside on the cytotoxicity, induction of apoptosis, and the putative pathways of its action in human breast cancer cells (MCF-7). For the analysis of apoptotic pathway, measurement of reactive oxygen species (ROS) and assessment of mitochondrial transmembrane potential (MTP) were achieved. We showed that stevioside was a potent inducer of apoptosis and it conveyed the apoptotic signal via intracellular ROS generation; thereby inducing change in MTP and induction of mitochondrial mediated apoptotic pathway. Taken together, our data indicated that stevioside induces the ROS-mediated mitochondrial permeability transition and results in the increased expression of apoptotic proteins such as Bax, Bcl-2 and Caspase-9. Effect of stevioside on stress-related transcription factors like NF-E2-related factor-2 opens up a new vista for further studies. This is the first report on the mechanism of the antibreast cancer (in vitro) activity of stevioside.

Paul S; Sengupta S; Bandyopadhyay TK; Bhattacharyya A

2012-01-01

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Emodin induces human T cell apoptosis in vitro by ROS-mediated endoplasmic reticulum stress and mitochondrial dysfunction.  

Science.gov (United States)

Aim:To elucidate the molecular mechanisms underlying the immunosuppressive effects of emodin isolated from Rheum palmatum L.Methods:Human T cells were isolated from the peripheral venous blood of 10 healthy adult donors. Cell viability was analyzed with MTT assay. AO/EB and Annexin V/PI staining and DNA damage assay were used to detect cell apoptosis. Fluorescence staining was used to detect the levels of ROS, the mitochondrial membrane potential and intracellular Ca(2+). Colorimetry was used to detect the levels of MDA and total SOD and GSH/GSSG ratio. The expression and activity of caspase-3, -4, and -9 were detected with Western blotting and a fluorometric assay. Western blotting was also used to detect the expression of Bcl-2, Bax, cytochrome C, and endoplasmic reticulum (ER) markers.Results:Emodin (1, 10, and 100 ?mol/L) inhibited the growth of human T cells and induced apoptosis in dose- and time dependent manners. Emodin triggered ER stress and significantly elevated intracellular free Ca(2+) in human T cells. It also disrupted mitochondrial membrane potential, and increased cytosolic level of cytochrome C, and the levels of activated cleavage fragments of caspase-3, -4, and -9 in human T cells. Furthermore, emodin significantly increased the levels of ROS and MDA, inhibited both SOD level and GSH/GSSG ratio in human T cells, whereas co-incubation with the ROS scavenger N-acetylcysteine (NAC, 20 ?mol/L) almost completely blocked emodin-induced ER stress and mitochondrial dysfunction in human T cells, and decreased the caspase cascade-mediated apoptosis.Conclusion:Emodin exerts immunosuppressive actions at least partly by inducing apoptosis of human T cells, which is triggered by ROS-mediated ER stress and mitochondrial dysfunction. PMID:23811723

Qu, Kai; Shen, Nai-Ying; Xu, Xin-Sen; Su, Hai-Bo; Wei, Ji-Chao; Tai, Ming-Hui; Meng, Fan-di; Zhou, Lei; Zhang, Yue-Lang; Liu, Chang

2013-07-01

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Salvianolic Acid B Induces Apoptosis in Human Glioma U87 Cells Through p38-Mediated ROS Generation.  

Science.gov (United States)

Salvianolic acid B (SalB), the main water-soluble bioactive compounds isolated from the traditional Chinese medical herb Danshen, has been shown to exert anti-cancer effect in several cancer cell lines. The aim of our study was to investigate the potential anti-cancer effect of SalB in human glioma U87 cells. We found that treatment with SalB significantly decreased cell viability of U87 cells in a dose- and time-dependent manner. SalB also enhanced the intracellular ROS generation and induced apoptotic cell death in U87 cells. Western blot analysis suggested that SalB increased the phosphorylation of p38 MAPK and p53 in a dose-dependent manner. Moreover, blocking p38 activation by specific inhibitor SB203580 or p38 specific siRNA partly reversed the anti-proliferative and pro-apoptotic effects, and ROS production induced by SalB treatment. The anti-tumor activity of SalB in vivo was also demonstrated in U87 xenograft glioma model. All of these findings extended the anti-cancer effect of SalB in human glioma cell lines, and suggested that these inhibitory effects of SalB on U87 glioma cell growth might be associated with p38 activation mediated ROS generation. Thus, SalB might be concerned as an effective and safe natural anticancer agent for glioma prevention and treatment. PMID:23842993

Wang, Zi-Shu; Luo, Peng; Dai, Shu-Hui; Liu, Zao-Bin; Zheng, Xin-Rui; Chen, Tao

2013-07-11

31

ROS-major mediators of extracellular matrix remodeling during tumor progression.  

UK PubMed Central (United Kingdom)

Extracellular matrices (ECMs) represent a complex network of proteins, proteoglycans and glycosaminoglycans (GAGs), composed of independent structural domains, ultimately constituting the cell microenvironment. As a highly organized, insoluble suprastructure, the ECM can, in a spatially patterned and regulated manner, integrate and deliver multiple complex signals to cells that affect their behavior. During the progression of carcinogenesis, tumor cells, through a continually changing interface, remodel and simultaneously interact with the components of ECM, as well as with surrounding stromal cells. Within this complex network of ECM components affecting tumor progression, reactive oxygen species/reactive nitrogen species (ROS/RNS) play a wide emerging role. In this minireview we will focus on the ROS-dependent modulations of tumor ECM and how this in turn affects the insidious pathways of tumor progression and dissemination.

Nikitovic D; Corsini E; Kouretas D; Tsatsakis A; Tzanakakis G

2013-06-01

32

Triterpenoid pristimerin induced HepG2 cells apoptosis through ROS-mediated mitochondrial dysfunction.  

UK PubMed Central (United Kingdom)

Purpose: To investigate the anticancer properties implicated in a natural triterpenoid (pristimerin)-induced apoptosis and inhibited proliferation in human hepatocellular carcinoma (HCC) HepG2 cell line. Methods: The cytotoxic activity of pristimerin in HepG2 cells was determined by MTT assay. Apoptotic morphology was observed by fluorescence microscope with Hoechst 33258 staining and percent apoptosis was measured by annexin V/PI double staining. DiOC6 for mitochondrial potential (??m) and DCFH-DA for reactive oxygen species (ROS) were determined by flow cytometry. Changes of apoptotic- related proteins were analysed by Western blot. Results: Pristimerin exerted a potent cytotoxic effect on HepG2 cells. After HepG2 cells were treated with pristimerin, typical apoptotic bodies, increasing the proportion of apoptotic annexin V-positive cells and activation of caspase-3 were detected in a dose-dependent manner. It was intriguing that pristimerin increased the generation of ROS with a collapse of the mitochondrial membrane potential in the cells. In addition, there was significant change in other mitochondrial membrane proteins triggered by pristimerin, such as Bcl-2 and Bax. Pristimerin also effectively induced subsequent release of cytochrome C from mitochondria into the cytosol, downregulated EGFR protein expression and inhibited downstream signaling pathways in HepG2 cells. Pretreatment with N-acetylcysteine (NAC) blocked ROS generation and resulted in loss of mitochondrial membrane potential, release of cytochrome C and apoptosis induced by pristimerin. Conclusion: These data indicate that ROS play an essential role in the induction of apoptosis by pristimerin in HepG2 cells.

Guo Y; Zhang W; Yan YY; Ma CG; Wang X; Wang C; Zhao JL

2013-04-01

33

Prevention effect in selenite-induced cataract in vivo and antioxidative effects in vitro of Crataegus pinnatifida leaves.  

Science.gov (United States)

Cataract is the leading cause of blindness worldwide. It is a multifactorial disease primarily associated with oxidative stress produced by free radicals. The present study was undertaken to evaluate the anticataract potential of Crataegus pinnatifida (hawthorn tree) leaves extract in selenite-induced cataract in vivo and antioxidant effects in vitro. In vitro antioxidant assay of C. pinnatifida leaves extract on NO production inhibition, aldose reductase inhibition, and O(2)(-) radical scavenging activities gave the IC(50) of 98.3, 89.7, and 5.98 ?g/mL, respectively. To characterize some major compounds in C. pinnatifida leaves extract, nine flavonoids were identified via LC-MS/MS qualitative analysis. Based on in vitro screening results, C. pinnatifida leaves extract eye drops in 0.1% hydroxypropyl methyl cellulose solution were prepared to evaluate the anticataract potential in vivo. Administration of C. pinnatifida leaves extract eye drops alternately three times a day in rat pups with selenite-induced oxidative stress significantly increased serum SOD and CAT activities, and tended to reduce MDA level compared with control group. The antioxidant enzyme SOD, CAT, and GSH activities in lens showed a significant increase. These results may be applied in the future for the prevention and treatment of cataracts. PMID:20596791

Wang, Tao; Zhang, Peng; Zhao, Chunfeng; Zhang, Yi; Liu, Hong; Hu, Limin; Gao, Xiumei; Zhang, Deqin

2010-07-02

34

Prevention effect in selenite-induced cataract in vivo and antioxidative effects in vitro of Crataegus pinnatifida leaves.  

UK PubMed Central (United Kingdom)

Cataract is the leading cause of blindness worldwide. It is a multifactorial disease primarily associated with oxidative stress produced by free radicals. The present study was undertaken to evaluate the anticataract potential of Crataegus pinnatifida (hawthorn tree) leaves extract in selenite-induced cataract in vivo and antioxidant effects in vitro. In vitro antioxidant assay of C. pinnatifida leaves extract on NO production inhibition, aldose reductase inhibition, and O(2)(-) radical scavenging activities gave the IC(50) of 98.3, 89.7, and 5.98 ?g/mL, respectively. To characterize some major compounds in C. pinnatifida leaves extract, nine flavonoids were identified via LC-MS/MS qualitative analysis. Based on in vitro screening results, C. pinnatifida leaves extract eye drops in 0.1% hydroxypropyl methyl cellulose solution were prepared to evaluate the anticataract potential in vivo. Administration of C. pinnatifida leaves extract eye drops alternately three times a day in rat pups with selenite-induced oxidative stress significantly increased serum SOD and CAT activities, and tended to reduce MDA level compared with control group. The antioxidant enzyme SOD, CAT, and GSH activities in lens showed a significant increase. These results may be applied in the future for the prevention and treatment of cataracts.

Wang T; Zhang P; Zhao C; Zhang Y; Liu H; Hu L; Gao X; Zhang D

2011-07-01

35

Induction of apoptosis in HL-60 cells through the ROS-mediated mitochondrial pathway by ramentaceone from Drosera aliciae.  

UK PubMed Central (United Kingdom)

Ramentaceone (1) is a naphthoquinone constituent of Drosera aliciae that exhibits potent cytotoxic activity against various tumor cell lines. However, its molecular mechanism of cell death induction has still not been determined. The present study demonstrates that 1 induces apoptosis in human leukemia HL-60 cells. Typical morphological and biochemical features of apoptosis were observed in 1-treated cells. Compound 1 induced a concentration-dependent increase in the sub-G1 fraction of the cell cycle. A decrease in the mitochondrial transmembrane potential (??m) was also observed. Furthermore, 1 reduced the ratio of anti-apoptotic Bcl-2 to pro-apoptotic Bax and Bak, induced cytochrome c release, and increased the activity of caspase 3. The generation of reactive oxygen species (ROS) was detected in 1-treated HL-60 cells, which was attenuated by the pretreatment of cells with a free radical scavenger, N-acetylcysteine (NAC). NAC also prevented the increase of the sub-G1 fraction induced by 1. These results indicate that ramentaceone induces cell death through the ROS-mediated mitochondrial pathway.

Kawiak A; Zawacka-Pankau J; Wasilewska A; Stasilojc G; Bigda J; Lojkowska E

2012-01-01

36

Induction of apoptosis in HL-60 cells through the ROS-mediated mitochondrial pathway by ramentaceone from Drosera aliciae.  

Science.gov (United States)

Ramentaceone (1) is a naphthoquinone constituent of Drosera aliciae that exhibits potent cytotoxic activity against various tumor cell lines. However, its molecular mechanism of cell death induction has still not been determined. The present study demonstrates that 1 induces apoptosis in human leukemia HL-60 cells. Typical morphological and biochemical features of apoptosis were observed in 1-treated cells. Compound 1 induced a concentration-dependent increase in the sub-G1 fraction of the cell cycle. A decrease in the mitochondrial transmembrane potential (??m) was also observed. Furthermore, 1 reduced the ratio of anti-apoptotic Bcl-2 to pro-apoptotic Bax and Bak, induced cytochrome c release, and increased the activity of caspase 3. The generation of reactive oxygen species (ROS) was detected in 1-treated HL-60 cells, which was attenuated by the pretreatment of cells with a free radical scavenger, N-acetylcysteine (NAC). NAC also prevented the increase of the sub-G1 fraction induced by 1. These results indicate that ramentaceone induces cell death through the ROS-mediated mitochondrial pathway. PMID:22250825

Kawiak, Anna; Zawacka-Pankau, Joanna; Wasilewska, Aleksandra; Stasilojc, Grzegorz; Bigda, Jacek; Lojkowska, Ewa

2012-01-17

37

V8, a newly synthetic flavonoid, induces apoptosis through ROS-mediated ER stress pathway in hepatocellular carcinoma.  

UK PubMed Central (United Kingdom)

Natural flavonoids from plants have been demonstrated to possess promising chemopreventive activities against various diseases. 7-{4-[Bis-(2-hydroxy-ethyl)-amino]-butoxy}-5-hydroxy-8-methoxy-2-phenyl-chromen-4-one (V8), a newly synthesized derivative of wogonin may have antioxidant, antiviral, anti-inflammatory and anti-tumor potentials as wogonin. Based on the recent findings of V8, the anti-tumor activities and fundamental mechanisms by which V8 inhibits growth of hepatocellular carcinoma were further investigated in this study. After the treatment of V8, a significant inhibition of HepG2 cell proliferation was observed in a dose-dependent manner with the IC50 value of 23 ?M using MTT assay. The exposure to V8 also resulted in apoptosis induction and an accumulation of ROS and Ca(2+). Meanwhile, a release of cytochrome c (Cyt-c), activation of BH-3 only proteins and Bax, decrease in mitochondrial membrane potential ??, as well as a suppression of Bcl-2, pro-caspase9 and pro-caspase3 expression were shown. Moreover, knocking down CHOP partly decreased the effect of V8-mediated apoptosis and activation of GRP78, p-PERK, p-eIF2?, ATF4 and CHOP modulated ER stress triggered by V8. In vivo, V8 inhibited the transplanted mice H22 liver carcinomas in a dose-dependent manner. Compared with wogonin, V8 exhibited stronger anti-proliferative effects both in vitro and in vivo. The underlying mechanism of activating PERK-eIF2?-ATF4 pathway by which V8 induces apoptosis was verified once again in vivo. The apoptosis induction via the mitochondrial pathway by modulating the ROS-mediated ER signaling pathway might serve to provide support for further studies of V8 as a possible anticancer drug in the clinical treatment of cancer.

Zhang Y; Zhao L; Li X; Wang Y; Yao J; Wang H; Li F; Li Z; Guo Q

2013-07-01

38

Baicalein abrogates reactive oxygen species (ROS)-mediated mitochondrial dysfunction during experimental pulmonary carcinogenesis in vivo.  

Science.gov (United States)

Our current study aimed to evaluate the chemotherapeutic efficacy of baicalein (BE) in Swiss albino mice, which is exposed to benzo(a)pyrene [B(a)P] for its ability to alleviate mitochondrial dysfunction and systolic failure. Here, we report that oral administration of B(a)P (50 mg/kg body weight)-induced pulmonary genotoxicities in mice was assessed in terms of elevation in reactive oxygen species (ROS) generation and DNA damage in lung mitochondria. MDA-DNA adducts were formed in immunohistochemical analysis, which confirmed nuclear DNA damage. mRNA expression levels studied by RT-PCR analysis of voltage-dependent anion channel (VDAC) and adenine nucleotide translocase (ANT) were found to be significantly decreased and showed a marked increase in membrane permeability transition pore (MPTP) opening. Accompanied by up-regulated Bcl-xL and down-regulated Bid, Bim and Cyt-c proteins studied by immunoblot were observed in B(a)P-induced lung cancer-bearing animals. Administration of BE (12 mg/kg body weight) significantly reversed all the above deleterious changes. Moreover, assessment of mitochondrial enzyme system revealed that BE treatment effectively counteracts B(a)P-induced down-regulated levels/activities of isocitrate dehydrogenase, ?-ketoglutarate dehydrogenase, succinate dehydrogenase, malate dehydrogenase, NADH dehydrogenase, cytochrome-C-oxidase and ATP levels. Restoration of mitochondria from oxidative damage was further confirmed by transmission electron microscopic examination. Further analysis of lipid peroxidation, superoxide dismutase, catalase, glutathione peroxidase, glutathione-S-transferase, glutathione reductase, reduced glutathione, vitamin E and vitamin C in lung mitochondria was carried out to substantiate the antioxidant effect of BE. The overall data conclude that chemotherapeutic efficacy of BE might have strong mitochondria protective and restoration capacity in sub-cellular level against lung carcinogenesis in Swiss albino mice. PMID:23061789

Naveenkumar, Chandrashekar; Raghunandhakumar, Subramanian; Asokkumar, Selvamani; Devaki, Thiruvengadam

2012-12-27

39

Baicalein abrogates reactive oxygen species (ROS)-mediated mitochondrial dysfunction during experimental pulmonary carcinogenesis in vivo.  

UK PubMed Central (United Kingdom)

Our current study aimed to evaluate the chemotherapeutic efficacy of baicalein (BE) in Swiss albino mice, which is exposed to benzo(a)pyrene [B(a)P] for its ability to alleviate mitochondrial dysfunction and systolic failure. Here, we report that oral administration of B(a)P (50 mg/kg body weight)-induced pulmonary genotoxicities in mice was assessed in terms of elevation in reactive oxygen species (ROS) generation and DNA damage in lung mitochondria. MDA-DNA adducts were formed in immunohistochemical analysis, which confirmed nuclear DNA damage. mRNA expression levels studied by RT-PCR analysis of voltage-dependent anion channel (VDAC) and adenine nucleotide translocase (ANT) were found to be significantly decreased and showed a marked increase in membrane permeability transition pore (MPTP) opening. Accompanied by up-regulated Bcl-xL and down-regulated Bid, Bim and Cyt-c proteins studied by immunoblot were observed in B(a)P-induced lung cancer-bearing animals. Administration of BE (12 mg/kg body weight) significantly reversed all the above deleterious changes. Moreover, assessment of mitochondrial enzyme system revealed that BE treatment effectively counteracts B(a)P-induced down-regulated levels/activities of isocitrate dehydrogenase, ?-ketoglutarate dehydrogenase, succinate dehydrogenase, malate dehydrogenase, NADH dehydrogenase, cytochrome-C-oxidase and ATP levels. Restoration of mitochondria from oxidative damage was further confirmed by transmission electron microscopic examination. Further analysis of lipid peroxidation, superoxide dismutase, catalase, glutathione peroxidase, glutathione-S-transferase, glutathione reductase, reduced glutathione, vitamin E and vitamin C in lung mitochondria was carried out to substantiate the antioxidant effect of BE. The overall data conclude that chemotherapeutic efficacy of BE might have strong mitochondria protective and restoration capacity in sub-cellular level against lung carcinogenesis in Swiss albino mice.

Naveenkumar C; Raghunandhakumar S; Asokkumar S; Devaki T

2013-04-01

40

Olaquindox-induced apoptosis is suppressed through p38 MAPK and ROS-mediated JNK pathways in HepG2 cells.  

UK PubMed Central (United Kingdom)

We investigated mitogen-activated protein kinase (MAPK) pathways as well as reactive oxygen species (ROS) in olaquindox-induced apoptosis. Exposure of HepG2 cells to olaquindox resulted in the phosphorylation of p38 MAPK and c-Jun N-terminal kinases (JNK). To confirm the role of p38 MAPK and JNK, HepG2 cells were pretreated with MAPKs-specific inhibitors prior to olaquindox treatment. Olaquindox-induced apoptosis was significantly potentiated by the JNK inhibitor (SP600125) or the p38 MAPK inhibitor (SB203580). Furthermore, we observed that olaquindox treatment led to ROS generation and that olaquindox-induced apoptosis and ROS generation were both significantly reduced by the antioxidants, superoxide dismutase and catalase. In addition, the levels of phosphorylation of JNK, but not p38 MAPK, were significantly suppressed after pretreatment of the antioxidants, while inhibition of the activations of JNK or p38 MAPK had no effect on ROS generation. This result suggested that ROS may be the upstream mediator for the activation of JNK. Conclusively, our results suggested that apoptosis in response to olaquindox treatment in HepG2 cells might be suppressed through p38 MAPK and ROS-JNK pathways.

Zhao WX; Tang SS; Jin X; Zhang CM; Zhang T; Wang CC; Sun Y; Xiao XL

2013-08-01

 
 
 
 
41

Olaquindox-induced apoptosis is suppressed through p38 MAPK and ROS-mediated JNK pathways in HepG2 cells.  

Science.gov (United States)

We investigated mitogen-activated protein kinase (MAPK) pathways as well as reactive oxygen species (ROS) in olaquindox-induced apoptosis. Exposure of HepG2 cells to olaquindox resulted in the phosphorylation of p38 MAPK and c-Jun N-terminal kinases (JNK). To confirm the role of p38 MAPK and JNK, HepG2 cells were pretreated with MAPKs-specific inhibitors prior to olaquindox treatment. Olaquindox-induced apoptosis was significantly potentiated by the JNK inhibitor (SP600125) or the p38 MAPK inhibitor (SB203580). Furthermore, we observed that olaquindox treatment led to ROS generation and that olaquindox-induced apoptosis and ROS generation were both significantly reduced by the antioxidants, superoxide dismutase and catalase. In addition, the levels of phosphorylation of JNK, but not p38 MAPK, were significantly suppressed after pretreatment of the antioxidants, while inhibition of the activations of JNK or p38 MAPK had no effect on ROS generation. This result suggested that ROS may be the upstream mediator for the activation of JNK. Conclusively, our results suggested that apoptosis in response to olaquindox treatment in HepG2 cells might be suppressed through p38 MAPK and ROS-JNK pathways. PMID:23812630

Zhao, Wen-Xia; Tang, Shu-Sheng; Jin, Xi; Zhang, Chao-Ming; Zhang, Ting; Wang, Cong-Cong; Sun, Yu; Xiao, Xi-Long

2013-06-30

42

ROS-Mediated Decline in Maximum Ca2+-Activated Force in Rat Skeletal Muscle Fibers following In Vitro and In Vivo Stimulation  

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We hypothesised that normal skeletal muscle stimulated intensely either in vitro or in situ would exhibit reactive oxygen species (ROS)-mediated contractile apparatus changes common to many pathophysiological conditions. Isolated soleus (SOL) and extensor digitorum longus (EDL) muscles of the rat we...

Dutka, Travis L.; Verburg, Esther; Larkins, Noni; Hortemo, Kristin H.; Lunde, Per K.; Sejersted, Ole M.; Lamb, Graham D.

43

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

UK PubMed Central (United Kingdom)

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.

Huai J; Vögtle FN; Jöckel L; Li Y; Kiefer T; Ricci JE; Borner C

2013-09-01

44

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  

Directory of Open Access Journals (Sweden)

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.

Yan He; Jiankun Cui; James C?M Lee; Shinghua Ding; Malgorzata Chalimoniuk; Agnes Simonyi; Albert Y Sun; Zezong Gu; Gary A Weisman?; W Gibson Wood; Grace Y Sun

2011-01-01

45

Dual phases of respiration chain defect-augmented mROS-mediated mCa 2+ stress during oxidative insult in normal and ? 0 RBA1 astrocytes.  

UK PubMed Central (United Kingdom)

Mitochondrial respiratory chain (RC) deficits, resulting in augmented mitochondrial ROS (mROS) generation, underlie pathogenesis of astrocytes. However, mtDNA-depleted cells (? (0)) lacking RC have been reported to be either sensitive or resistant to apoptosis. In this study, we sought to determine the effects of RC-enhanced mitochondrial stress following oxidative insult. Using noninvasive fluorescence probe-coupled laser scanning imaging microscopy, the ability to resist oxidative stress and levels of mROS formation and mitochondrial calcium (mCa(2+)) were compared between two different astrocyte cell lines, control and ? (0) astrocytes, over time upon oxidative stress. Our results showed that the cytoplasmic membrane becomes permeated with YO-PRO-1 dye at 150 and 130 minutes in RBA-1 and ? (0) astrocytes, respectively. In contrast to RBA-1, 30 minutes after 20 mM H2O2 exposure, ? (0) astrocytes formed marked plasma membrane blebs, lost the ability to retain Mito-R, and showed condensation of nuclei. Importantly, H2O2-induced ROS and accompanied mCa(2+) elevation in control showed higher levels than ? (0) at early time point but vice versa at late time point. Our findings underscore dual phase of RC-defective cells harboring less mitochondrial stress due to low RC activity during short-term oxidative stress but augmented mROS-mediated mCa(2+) stress during severe oxidative insult.

Peng TI; Lin MS; Jou MJ

2013-01-01

46

Dual phases of respiration chain defect-augmented mROS-mediated mCa 2+ stress during oxidative insult in normal and ? 0 RBA1 astrocytes.  

Science.gov (United States)

Mitochondrial respiratory chain (RC) deficits, resulting in augmented mitochondrial ROS (mROS) generation, underlie pathogenesis of astrocytes. However, mtDNA-depleted cells (? (0)) lacking RC have been reported to be either sensitive or resistant to apoptosis. In this study, we sought to determine the effects of RC-enhanced mitochondrial stress following oxidative insult. Using noninvasive fluorescence probe-coupled laser scanning imaging microscopy, the ability to resist oxidative stress and levels of mROS formation and mitochondrial calcium (mCa(2+)) were compared between two different astrocyte cell lines, control and ? (0) astrocytes, over time upon oxidative stress. Our results showed that the cytoplasmic membrane becomes permeated with YO-PRO-1 dye at 150 and 130 minutes in RBA-1 and ? (0) astrocytes, respectively. In contrast to RBA-1, 30 minutes after 20 mM H2O2 exposure, ? (0) astrocytes formed marked plasma membrane blebs, lost the ability to retain Mito-R, and showed condensation of nuclei. Importantly, H2O2-induced ROS and accompanied mCa(2+) elevation in control showed higher levels than ? (0) at early time point but vice versa at late time point. Our findings underscore dual phase of RC-defective cells harboring less mitochondrial stress due to low RC activity during short-term oxidative stress but augmented mROS-mediated mCa(2+) stress during severe oxidative insult. PMID:23533684

Peng, Tsung-I; Lin, Muh-Shi; Jou, Mei-Jie

2013-03-10

47

ROS and ERK1/2-mediated caspase-9 activation increases XAF1 expression in dexamethasone-induced apoptosis of EBV-transformed B cells.  

UK PubMed Central (United Kingdom)

Dexamethasone (Dex) inhibits the growth of diverse types of cancer cells and is utilized clinically for the therapy of hematological malignancies. In this study, we investigated the molecular mechanisms of Dex action in the apoptosis of Epstein-Barr virus (EBV)-transformed B cells. We showed that Dex inhibited the proliferation of EBV-transformed B cells and induced apoptosis by activating caspase-9, -3 and -8. While activation of caspase-9 was triggered as early as 2 h after Dex treatment, cleavage of caspase-8 was deferred and was found 8 h after the exposure. Dex-dependent activation of caspase-8 was blocked by the specific caspase-9 inhibitor, z-LEHD-fmk. Moreover, Dex significantly increased the expression of X-linked inhibitor of apoptosis (XIAP)?associated factor 1 (XAF1) and induced the translocation of XAF1 into the cytosol. Cytosolic XAF1 with Puma induced the translocation of Bax into mitochondria. Dex led to up-regulation of reactive oxygen species (ROS) generation and the phosphorylation of ERK1/2 after the exposure. We speculated that ROS generation might be the first event of Dex-induced apoptosis because ROS inhibitor NAC abrogated ROS production and ERK1/2 activation, but PD98059 did not block ROS production. NAC and PD98059 also suppressed the translocation of XAF1, Puma and Bax into mitochondria. These results demonstrated that Dex-mediated activation of caspase-9 via ROS generation and ERK1/2 pathway activation resulted in the activation of caspase-8 and the increment of XAF1, thereby induced apoptosis of EBV-transformed B cells. These findings suggest that Dex constitutes a probable therapy for EBV-associated hematological malignancies.

Park GB; Choi Y; Kim YS; Lee HK; Kim D; Hur DY

2013-07-01

48

?-Catenin mediates cyclic strain-stimulated cardiomyogenesis in mouse embryonic stem cells through ROS-dependent and integrin-mediated PI3K/Akt pathways.  

Science.gov (United States)

Wnt/?-catenin signaling regulates various cellular events involved in the proliferation and differentiation and these events are affected sensitively by applying to mechanical stimuli. However, the mechanisms by which mechanical force stimulates cardiomyogenesis are not extensively explored. In this study we investigated the cellular mechanisms by which ?-catenin signaling regulates cardiac differentiation of strain-subjected embryonic stem (ES) cells. The application of cells to cyclic strain increased beating cardiomyocyte foci with the attendant increases of Cx 43 and Nkx 2.5 proteins. Anti-oxidants such as vitamin C or N-acetyl cysteine (NAC) blocked the strain-mediated increases of Cx 43, Nkx 2.5, and ?5/?1 integrins. These anti-oxidants also suppressed the activation of phosphoinositide 3-kinase (PI3K) and Akt in cyclic strain-subjected cells. Western blot analysis revealed that PI3K is a critical downstream effector of ?1 integrin signaling and mediates Cx 43 and Nkx 2.5 expression in cyclic strain-applied ES cells. Cyclic strain increased the expression of ?-catenin and stimulated its nuclear translocation from the cytosol, which was prevented by anti-oxidant treatment. In addition, the application to cyclic strain increased mRNA expression of ?-catenin target genes, Axin2 and c-myc, as well as the phosphorylation of glycogen synthase kinase-3?. Furthermore, the blockage of ?-catenin by its specific siRNA transfection diminished the cellular levels of Cx 43 and Nkx 2.5 proteins and the number of beating cardiomyocyte foci. Collectively, these results suggest that ?-catenin-mediated signaling is required for cyclic strain-stimulated cardiomyogenesis through ROS-dependent and integrin-mediated PI3K-Akt signaling cascades. PMID:21433060

Heo, Jung Sun; Lee, Jeong-Chae

2011-07-01

49

?-Catenin mediates cyclic strain-stimulated cardiomyogenesis in mouse embryonic stem cells through ROS-dependent and integrin-mediated PI3K/Akt pathways.  

UK PubMed Central (United Kingdom)

Wnt/?-catenin signaling regulates various cellular events involved in the proliferation and differentiation and these events are affected sensitively by applying to mechanical stimuli. However, the mechanisms by which mechanical force stimulates cardiomyogenesis are not extensively explored. In this study we investigated the cellular mechanisms by which ?-catenin signaling regulates cardiac differentiation of strain-subjected embryonic stem (ES) cells. The application of cells to cyclic strain increased beating cardiomyocyte foci with the attendant increases of Cx 43 and Nkx 2.5 proteins. Anti-oxidants such as vitamin C or N-acetyl cysteine (NAC) blocked the strain-mediated increases of Cx 43, Nkx 2.5, and ?5/?1 integrins. These anti-oxidants also suppressed the activation of phosphoinositide 3-kinase (PI3K) and Akt in cyclic strain-subjected cells. Western blot analysis revealed that PI3K is a critical downstream effector of ?1 integrin signaling and mediates Cx 43 and Nkx 2.5 expression in cyclic strain-applied ES cells. Cyclic strain increased the expression of ?-catenin and stimulated its nuclear translocation from the cytosol, which was prevented by anti-oxidant treatment. In addition, the application to cyclic strain increased mRNA expression of ?-catenin target genes, Axin2 and c-myc, as well as the phosphorylation of glycogen synthase kinase-3?. Furthermore, the blockage of ?-catenin by its specific siRNA transfection diminished the cellular levels of Cx 43 and Nkx 2.5 proteins and the number of beating cardiomyocyte foci. Collectively, these results suggest that ?-catenin-mediated signaling is required for cyclic strain-stimulated cardiomyogenesis through ROS-dependent and integrin-mediated PI3K-Akt signaling cascades.

Heo JS; Lee JC

2011-07-01

50

ROS generated by CYP450, especially CYP2E1, mediate mitochondrial dysfunction induced by tetrandrine in rat hepatocytes.  

UK PubMed Central (United Kingdom)

AIM: Tetrandrine, an alkaloid with a remarkable pharmacological profile, induces oxidative stress and mitochondrial dysfunction in hepatocytes; however, mitochondria are not the direct target of tetrandrine, which prompts us to elucidate the role of oxidative stress in tetrandrine-induced mitochondrial dysfunction and the sources of oxidative stress. METHODS: Rat primary hepatocytes were isolated by two-step collagenase perfusion. Mitochondrial function was evaluated by analyzing ATP content, mitochondrial membrane potential (MMP) and the mitochondrial permeability transition. The oxidative stress was evaluated by examining changes in the levels of reactive oxygen species (ROS) and glutathione (GSH). RESULTS: ROS scavengers largely attenuated the cytotoxicity induced by tetrandrine in rat hepatocytes, indicating the important role of ROS in the hepatotoxicity of tetrandrine. Of the multiple ROS inhibitors that were tested, only inhibitors of CYP450 (SKF-525A and others) reduced the ROS levels and ameliorated the depletion of GSH. Mitochondrial function assays showed that the mitochondrial permeability transition (MPT) induced by tetrandrine was inhibited by SKF-525A and vitamin C (VC), both of which also rescued the depletion of ATP levels and the mitochondrial membrane potential. Upon inhibiting specific CYP450 isoforms, we observed that the inhibitors of CYP2D, CYP2C, and CYP2E1 attenuated the ATP depletion that occurred following tetrandrine exposure, whereas the inhibitors of CYP2D and CYP2E1 reduced the ROS induced by tetrandrine. Overexpression of CYP2E1 enhanced the tetrandrine-induced cytotoxicity. CONCLUSION: We demonstrated that CYP450 plays an important role in the mitochondrial dysfunction induced by the administration of tetrandrine. ROS generated by CYP450, especially CYP2E1, may contribute to the mitochondrial dysfunction induced by tetrandrine.

Qi XM; Miao LL; Cai Y; Gong LK; Ren J

2013-09-01

51

ROS generated by CYP450, especially CYP2E1, mediate mitochondrial dysfunction induced by tetrandrine in rat hepatocytes.  

Science.gov (United States)

Aim:Tetrandrine, an alkaloid with a remarkable pharmacological profile, induces oxidative stress and mitochondrial dysfunction in hepatocytes; however, mitochondria are not the direct target of tetrandrine, which prompts us to elucidate the role of oxidative stress in tetrandrine-induced mitochondrial dysfunction and the sources of oxidative stress.Methods:Rat primary hepatocytes were isolated by two-step collagenase perfusion. Mitochondrial function was evaluated by analyzing ATP content, mitochondrial membrane potential (MMP) and the mitochondrial permeability transition. The oxidative stress was evaluated by examining changes in the levels of reactive oxygen species (ROS) and glutathione (GSH).Results:ROS scavengers largely attenuated the cytotoxicity induced by tetrandrine in rat hepatocytes, indicating the important role of ROS in the hepatotoxicity of tetrandrine. Of the multiple ROS inhibitors that were tested, only inhibitors of CYP450 (SKF-525A and others) reduced the ROS levels and ameliorated the depletion of GSH. Mitochondrial function assays showed that the mitochondrial permeability transition (MPT) induced by tetrandrine was inhibited by SKF-525A and vitamin C (VC), both of which also rescued the depletion of ATP levels and the mitochondrial membrane potential. Upon inhibiting specific CYP450 isoforms, we observed that the inhibitors of CYP2D, CYP2C, and CYP2E1 attenuated the ATP depletion that occurred following tetrandrine exposure, whereas the inhibitors of CYP2D and CYP2E1 reduced the ROS induced by tetrandrine. Overexpression of CYP2E1 enhanced the tetrandrine-induced cytotoxicity.Conclusion:We demonstrated that CYP450 plays an important role in the mitochondrial dysfunction induced by the administration of tetrandrine. ROS generated by CYP450, especially CYP2E1, may contribute to the mitochondrial dysfunction induced by tetrandrine. PMID:23892269

Qi, Xin-Ming; Miao, Ling-Ling; Cai, Yan; Gong, Li-Kun; Ren, Jin

2013-07-29

52

Ursodeoxycholic acid prevents selenite-induced oxidative stress and alleviates cataract formation: In vitro and in vivo studies.  

UK PubMed Central (United Kingdom)

OBJECTIVE: To evaluate the antioxidative and anticataractogenic potential effect of ursodeoxycholic acid (UDCA) on selenite-induced cataract in vitro and in vivo. METHODS: Enucleated rat lenses were incubated in M199 medium alone (Group I), with 200 ?M selenite (Group II), or with 200 ?M selenite and 500 ?M UDCA (Group III). Selenite was administered on the third day and UDCA treatment was from the second to the fifth day. The development of cataracts was observed under an inverted microscope. Total antioxidative capabilities (T-AOC), mean activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (Gpx), glutathione reductase (GR) and glutathione S-transferase (GST), levels of reduced glutathione (GSH), malondialdehyde (MDA), and total sulfhydryl content were analyzed in lenticular samples. In vivo, cataracts were induced in 12-day-old pups by single subcutaneous injections of sodium selenite. The test groups received 180 mg/kg bodyweight/day of UDCA intraperitoneally on postpartum days 11-16 or 0.5% UDCA drops four times daily on postpartum days 11-25. RESULTS: In vitro, morphological examination of the lenses revealed dense vacuolization and opacification in Group II, minimal vacuolization in 12.5% of Group III, and no opacification in 87.5% of Group III. In Group I, all lenses were clear. UDCA significantly (p<0.05) restored GSH and total sulfhydryl, and decreased MDA levels. T-AOC and the mean activities of the antioxidant enzymes were elevated following treatment with UDCA. In vivo, 0.5% UDCA drops resulted in only 20% nuclear cataract development and 180 mg/kg of UDCA intraperitoneally led to 50% development, compared to 100% in the control group (p<0.05). CONCLUSIONS: UDCA prevents selenite toxicity and cataractogenesis by maintaining antioxidant status and GSH, protecting the sulfhydryl group, and inhibiting lipid peroxidation in lenses.

Qi HP; Wei SQ; Gao XC; Yu NN; Hu WZ; Bi S; Cui H

2012-01-01

53

TNF-?, erectile dysfunction, and NADPH oxidase-mediated ROS generation in corpus cavernosum in high-fat diet/streptozotocin-induced diabetic rats.  

UK PubMed Central (United Kingdom)

INTRODUCTION: Patients with diabetes-associated erectile dysfunction (ED) are characterized by an increase in circulating tumor necrosis factor-alpha (TNF-?). However, no study has indicated whether and how TNF-? plays a role in the pathogenesis of ED associated with diabetes. AIM: We examined the effects and potential mechanism of infliximab (INF), a chimeric monoclonal antibody to TNF-?, on reactive oxygen species (ROS) generation in corpus cavernosum and ED in diabetic rats. METHODS: Four groups of male rats were used: age-matched normal controls; diabetic rats induced by a high-fat diet (HFD) combined with a single streptozotocin (STZ) injection (35?mg/kg body weight, intraperitoneal [i.p.]); nondiabetic rats receiving INF (5?mg/kg body weight/week, i.p.), and diabetic rats receiving INF. Erectile function was assessed with electrical stimulation of the cavernous nerve after 8 weeks. The blood and penile tissues were harvested for plasma biochemical determinations, serum TNF-? measurement, penile ROS detection, and molecular assays of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunits, endothelial nitric oxide synthase (eNOS), phospho-eNOS, and neural nitric oxide synthase (nNOS) in the penis. MAIN OUTCOME MEASURES: The effect of INF on HFD/STZ-induced diabetic ED and NADPH oxidase-mediated ROS generation was studied in diabetic corpus cavernosum. RESULTS: Untreated diabetic rats displayed significantly decreased erectile parameters, and increased plasma TNF-? levels, penile ROS production, p47(phox) and gp91(phox) expression compared with nondiabetic controls. INF neutralized TNF-? and significantly reduced ED in diabetic rats, in which marked decreases in p47(phox) and gp91(phox) expression and ROS generation in corpus cavernosum were noted. The ratio of phospho-eNOS to eNOS and expression of nNOS in the penis were significantly increased in INF-treated vs. untreated diabetic rats. CONCLUSIONS: Increased TNF-? expression associated with diabetes contributes to ED by promoting NAPDH oxidase-mediated ROS generation in corpus cavernosum. INF protects against diabetic ED by neutralizing TNF-?.

Long T; Liu G; Wang Y; Chen Y; Zhang Y; Qin D

2012-07-01

54

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

UK PubMed Central (United Kingdom)

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.

Sakai E; Shimada-Sugawara M; Yamaguchi Y; Sakamoto H; Fumimoto R; Fukuma Y; Nishishita K; Okamoto K; Tsukuba T

2013-01-01

55

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

2013-03-29

56

Electromagnetic fields induce neural differentiation of human bone marrow derived mesenchymal stem cells via ROS mediated EGFR activation.  

UK PubMed Central (United Kingdom)

Even though the inducing effect of electromagnetic fields (EMF) on the neural differentiation of human bone marrow mesenchymal stem cells (hBM-MSCs) is a distinctive, the underlying mechanism of differentiation remains unclear. To find out the signaling pathways involved in the neural differentiation of BM-MSCs by EMF, we examined the CREB phosphorylation and Akt or ERK activation as an upstream of CREB. In hBM-MSCs treated with ELF-EMF (50 Hz, 1 mT), the expression of neural markers such as NF-L, MAP2, and NeuroD1 increased at 6 days and phosphorylation of Akt and CREB but not ERK increased at 90 min in BM-MSCs. Moreover, EMF increased phosphorylation of epidermal growth factor receptor (EGFR) as an upstream receptor tyrosine kinase of PI3K/Akt at 90 min. It has been well documented that ELF-MF exposure may alter cellular processes by increasing intracellular reactive oxygen species (ROS) concentrations. Thus, we examined EMF-induced ROS production in BM-MSCs. Moreover, pretreatment with a ROS scavenger, N-acetylcystein, and an EGFR inhibitor, AG-1478, prevented the phosphorylation of EGFR and downstream molecules. These results suggest that EMF induce neural differentiation through activation of EGFR signaling and mild generation of ROS.

Park JE; Seo YK; Yoon HH; Kim CW; Park JK; Jeon S

2013-03-01

57

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

2012-11-23

58

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

UK PubMed Central (United Kingdom)

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.

Rains JL; Kanikarla-Marie P; Jain SK

2012-12-01

59

Chamaejasmine Induces Apoptosis in Human Lung Adenocarcinoma A549 Cells through a Ros-Mediated Mitochondrial Pathway  

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In the present study, the anticancer activity of chamaejasmine towards A549 human lung adenocarcinoma cells was investigated. In order to explore the underlying mechanism of cell growth inhibition of chamaejasmine, cell cycle distribution, ROS generation, mitochondrial membrane potential (??m) disru...

Hongyang Yu; Tingting Zhang; Li Cai; Yuanyuan Qu; Songliu Hu; Guanglu Dong; Rongwei Guan; Xiangying Xu; Lina Xing

60

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

Science.gov (United States)

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

2012-06-08

 
 
 
 
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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

2013-05-20

62

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.  

UK PubMed Central (United Kingdom)

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.

Su J; Lai H; Chen J; Li L; Wong YS; Chen T; Li X

2013-01-01

63

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; Jheng-Fong Lee; Jyh-Yih Chen

2011-01-01

64

Cyanidin reverses cisplatin-induced apoptosis in HK-2 proximal tubular cells through inhibition of ROS-mediated DNA damage and modulation of the ERK and AKT pathways.  

UK PubMed Central (United Kingdom)

Cyanidin is an anthocyanin widely distributed in food diet with novel antioxidant activity. Herein, we investigated the protective effects of cyanidin on HK-2 proximal tubular cells against cisplatin-induced apoptosis and elucidated the underlying mechanisms. The results showed that cisplatin-induced apoptosis in HK-2 cells was significantly attenuated by cyanidin. The cleavage of caspases and PARP, activation of p53 and mitochondrial-mediated apoptosis pathways induced by cisplatin were effectively blocked by cyanidin. Moreover, cyanidin significantly suppressed the overproduction of ROS, and activation of ERK and AKT pathways triggered by cisplatin. Our results indicate that cyanidin exhibits therapeutic potential in prevention of cisplatin-induced nephrotoxicity.

Gao S; Chen T; Choi MY; Liang Y; Xue J; Wong YS

2013-06-01

65

Cyanidin reverses cisplatin-induced apoptosis in HK-2 proximal tubular cells through inhibition of ROS-mediated DNA damage and modulation of the ERK and AKT pathways.  

Science.gov (United States)

Cyanidin is an anthocyanin widely distributed in food diet with novel antioxidant activity. Herein, we investigated the protective effects of cyanidin on HK-2 proximal tubular cells against cisplatin-induced apoptosis and elucidated the underlying mechanisms. The results showed that cisplatin-induced apoptosis in HK-2 cells was significantly attenuated by cyanidin. The cleavage of caspases and PARP, activation of p53 and mitochondrial-mediated apoptosis pathways induced by cisplatin were effectively blocked by cyanidin. Moreover, cyanidin significantly suppressed the overproduction of ROS, and activation of ERK and AKT pathways triggered by cisplatin. Our results indicate that cyanidin exhibits therapeutic potential in prevention of cisplatin-induced nephrotoxicity. PMID:23360684

Gao, Si; Chen, Tianfeng; Choi, Mei-Yuk; Liang, Yuanwei; Xue, Junyi; Wong, Yum-Shing

2013-01-27

66

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

Directory of Open Access Journals (Sweden)

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

2012-01-01

67

Antioxidant dieckol downregulates the Rac1/ROS signaling pathway and inhibits Wiskott-Aldrich syndrome protein (WASP)-family verprolin-homologous protein 2 (WAVE2)-mediated invasive migration of B16 mouse melanoma cells.  

UK PubMed Central (United Kingdom)

Reactive oxygen species (ROS) generation is linked to dynamic actin cytoskeleton reorganization, which is involved in tumor cell motility and metastasis. Thus, inhibition of ROS generation and actin polymerization in tumor cells may represent an effective anticancer strategy. However, the molecular basis of this signaling pathway is currently unknown. Here, we show that the Ecklonia cava-derived antioxidant dieckol downregulates the Rac1/ROS signaling pathway and inhibits Wiskott-Aldrich syndrome protein (WASP)-family verprolin-homologous protein 2 (WAVE2)-mediated invasive migration of B16 mouse melanoma cells. Steady-state intracellular ROS levels were higher in malignant B16F10 cells than in parental, nonmetastatic B16F0 cells. Elevation of ROS by H(2)O(2) treatment increased migration and invasion ability of B16F0 cells to level similar to that of B16F10 cells, suggesting that intracellular ROS signaling mediates the prometastatic properties of B16 mouse melanoma cells. ROS levels and the cell migration and invasion ability of B16 melanoma cells correlated with Rac1 activation and WAVE2 expression. Overexpression of dominant negative Rac1 and depletion of WAVE2 by siRNA suppressed H(2)O(2)-induced cell invasion of B16F0 and B16F10 cells. Similarly, dieckol attenuates the ROS-mediated Rac1 activation and WAVE2 expression, resulting in decreased migration and invasion of B16 melanoma cells. In addition, we found that dieckol decreases association between WAVE2 and NADPH oxidase subunit p47(phox). Therefore, this finding suggests that WAVE2 acts to couple intracellular Rac1/ROS signaling to the invasive migration of B16 melanoma cells, which is inhibited by dieckol.

Park SJ; Kim YT; Jeon YJ

2012-04-01

68

Isoobtusilactone A sensitizes human hepatoma Hep G2 cells to TRAIL-induced apoptosis via ROS and CHOP-mediated up-regulation of DR5.  

UK PubMed Central (United Kingdom)

Hepatoma cells are relatively resistant to TRAIL. We have previously shown that isoobtusilactone A (IOA), a potent anticancer agent isolated from Cinnamomum kotoense, induced mitochondria-mediated apoptosis in hepatoma cells. Here, we report that IOA could potentiate TRAIL-induced apoptosis in Hep G2 cells. The combined treatment with IOA and TRAIL significantly induced caspase-dependent apoptosis. This correlated with the up-regulation of C/EBP homologous protein (CHOP) and death receptor 5 (DR5) protein levels. Gene silencing of the DR5 by small interfering RNA abrogated the apoptosis induced by the combined regimen of IOA and TRAIL, suggesting that the sensitization to TRAIL was mediated through DR5. By analyzing the DR5 promoter, we found that IOA induced a CHOP-dependent DR5 transactivation. DR5 expression after IOA treatment was accompanied by provoking intracellular reactive oxygen species (ROS) generation. Pretreatment with N-acetyl-L-cysteine (NAC) attenuated IOA-induced CHOP and DR5 expression and inhibited TRAIL-induced apoptosis. Taken together, our data suggested that ROS-dependent and CHOP-regulated DR5 expression played a pivotal role in the synergistic enhancement of TRAIL-induced apoptosis instigated by IOA in Hep G2 cells.

Chen CY; Yiin SJ; Hsu JL; Wang WC; Lin SC; Chern CL

2012-04-01

69

Synergistic antitumour activity of sorafenib in combination with tetrandrine is mediated by reactive oxygen species (ROS)/Akt signaling.  

UK PubMed Central (United Kingdom)

BACKGROUND: Sorafenib is a potent inhibitor against Raf kinase and several receptor tyrosine kinases that has been approved for the clinical treatment of advanced renal and liver cancer. Combining sorafenib with other agents has been shown to improve its antitumour efficacy by not only reducing the toxic side effects but also preventing primary and acquired resistance to sorafenib. We have previously observed that tetrandrine exhibits potent antitumour effects in human hepatocellular carcinoma. In this study, we investigated the synergistic antitumour activity of sorafenib in combination with tetrandrine. METHODS: This was a two-part investigation that included the in vitro effects of sorafenib in combination with tetrandrine on cancer cells and the in vivo antitumour efficacy of this drug combination on tumour xenografts in nude mice. RESULTS: Combined treatment showed a good synergistic antitumour effect yet spared non-tumourigenic cells. The potential molecular mechanism may be mainly that it activated mitochondrial death pathway and induced caspase-dependent apoptosis in the cancer cells. Accumulation of intracellular reactive oxygen species (ROS) and subsequent activation of Akt may also be involved in apoptosis induction. CONCLUSION: The antitumour activity of sorafenib plus tetrandrine may be attributed to the induction of the intrinsic apoptosis pathway through ROS/Akt signaling. This finding provides a novel approach that may broaden the clinical application of sorafenib.

Wan J; Liu T; Mei L; Li J; Gong K; Yu C; Li W

2013-07-01

70

Kaempferol inhibits P. intermedia lipopolysaccharide-induced production of nitric oxide through translational regulation in murine macrophages: critical role of heme oxygenase-1-mediated ROS reduction.  

UK PubMed Central (United Kingdom)

BACKGROUND: Nitric oxide (NO) could be a potential target for the development of new therapeutic approaches to the treatment of periodontal disease because this molecule plays a significant role in the tissue destruction observed in periodontitis. In this study, the authors investigate the effect of kaempferol on the production of NO by murine macrophage-like RAW264.7 cells stimulated with lipopolysaccharide (LPS) from Prevotella intermedia, a pathogen implicated in periodontal disease, and try to determine the underlying mechanisms of action. METHODS: NO production was assayed by measuring the accumulation of nitrite in culture supernatants. Real-time polymerase chain reaction was performed to quantify inducible NO synthase (iNOS) and heme oxygenase-1 (HO-1) mRNA expression. iNOS and HO-1 protein expression and phosphorylation of c-Jun N-terminal kinase and p38 were characterized via immunoblot analysis. Reactive oxygen species (ROS) production was measured using the redox-sensitive fluorescent probe 2',7'-dichlorodihydrofluorescein diacetate. RESULTS: Kaempferol significantly inhibited NO production and expression of iNOS protein in P. intermedia LPS-stimulated RAW246.7 cells without affecting iNOS mRNA expression. Kaempferol upregulated HO-1 expression in LPS-activated cells. Inhibition of HO-1 activity by tin protoporphyrin IX (SnPP) abolished the suppressive effect of kaempferol on NO production. In addition, kaempferol significantly attenuated P. intermedia LPS-induced increase of intracellular ROS, and SnPP blocked this reduction. Treatment with antioxidants downregulated the production of LPS-induced NO. CONCLUSIONS: Kaempferol inhibits NO production and iNOS protein expression in P. intermedia LPS-stimulated RAW264.7 cells at the translational level via HO-1-mediated ROS reduction and could be an efficient modulator of host response in the treatment of periodontal disease.

Choi IS; Choi EY; Jin JY; Park HR; Choi JI; Kim SJ

2013-04-01

71

Fucoidan derived from Undaria pinnatifida induces apoptosis in human hepatocellular carcinoma SMMC-7721 cells via the ROS-mediated mitochondrial pathway.  

Science.gov (United States)

Fucoidans, fucose-enriched sulfated polysaccharides isolated from brown algae and marine invertebrates, have been shown to exert anticancer activity in several types of human cancer, including leukemia and breast cancer and in lung adenocarcinoma cells. In the present study, the anticancer activity of the fucoidan extracted from the brown seaweed Undaria pinnatifida was investigated in human hepatocellular carcinoma SMMC-7721 cells, and the underlying mechanisms of action were investigated. SMMC-7721 cells exposed to fucoidan displayed growth inhibition and several typical features of apoptotic cells, such as chromatin condensation and marginalization, a decrease in the number of mitochondria, and in mitochondrial swelling and vacuolation. Fucoidan-induced cell death was associated with depletion of reduced glutathione (GSH), accumulation of high intracellular levels of reactive oxygen species (ROS), and accompanied by damage to the mitochondrial ultrastructure, depolarization of the mitochondrial membrane potential (MMP, ??m) and caspase activation. Moreover, fucoidan led to altered expression of factors related to apoptosis, including downregulating Livin and XIAP mRNA, which are members of the inhibitor of apoptotic protein (IAP) family, and increased the Bax-to-Bcl-2 ratio. These findings suggest that fucoidan isolated from U. pinnatifida induced apoptosis in SMMC-7721 cells via the ROS-mediated mitochondrial pathway. PMID:23752353

Yang, Lili; Wang, Peisheng; Wang, Huaxin; Li, Qiaomei; Teng, Hongming; Liu, Zhichao; Yang, Wenbo; Hou, Lin; Zou, Xiangyang

2013-06-10

72

Fucoidan derived from Undaria pinnatifida induces apoptosis in human hepatocellular carcinoma SMMC-7721 cells via the ROS-mediated mitochondrial pathway.  

UK PubMed Central (United Kingdom)

Fucoidans, fucose-enriched sulfated polysaccharides isolated from brown algae and marine invertebrates, have been shown to exert anticancer activity in several types of human cancer, including leukemia and breast cancer and in lung adenocarcinoma cells. In the present study, the anticancer activity of the fucoidan extracted from the brown seaweed Undaria pinnatifida was investigated in human hepatocellular carcinoma SMMC-7721 cells, and the underlying mechanisms of action were investigated. SMMC-7721 cells exposed to fucoidan displayed growth inhibition and several typical features of apoptotic cells, such as chromatin condensation and marginalization, a decrease in the number of mitochondria, and in mitochondrial swelling and vacuolation. Fucoidan-induced cell death was associated with depletion of reduced glutathione (GSH), accumulation of high intracellular levels of reactive oxygen species (ROS), and accompanied by damage to the mitochondrial ultrastructure, depolarization of the mitochondrial membrane potential (MMP, ??m) and caspase activation. Moreover, fucoidan led to altered expression of factors related to apoptosis, including downregulating Livin and XIAP mRNA, which are members of the inhibitor of apoptotic protein (IAP) family, and increased the Bax-to-Bcl-2 ratio. These findings suggest that fucoidan isolated from U. pinnatifida induced apoptosis in SMMC-7721 cells via the ROS-mediated mitochondrial pathway.

Yang L; Wang P; Wang H; Li Q; Teng H; Liu Z; Yang W; Hou L; Zou X

2013-06-01

73

Fucoidan Derived from Undaria pinnatifida Induces Apoptosis in Human Hepatocellular Carcinoma SMMC-7721 Cells via the ROS-Mediated Mitochondrial Pathway  

Directory of Open Access Journals (Sweden)

Full Text Available Fucoidans, fucose-enriched sulfated polysaccharides isolated from brown algae and marine invertebrates, have been shown to exert anticancer activity in several types of human cancer, including leukemia and breast cancer and in lung adenocarcinoma cells. In the present study, the anticancer activity of the fucoidan extracted from the brown seaweed Undaria pinnatifida was investigated in human hepatocellular carcinoma SMMC-7721 cells, and the underlying mechanisms of action were investigated. SMMC-7721 cells exposed to fucoidan displayed growth inhibition and several typical features of apoptotic cells, such as chromatin condensation and marginalization, a decrease in the number of mitochondria, and in mitochondrial swelling and vacuolation. Fucoidan-induced cell death was associated with depletion of reduced glutathione (GSH), accumulation of high intracellular levels of reactive oxygen species (ROS), and accompanied by damage to the mitochondrial ultrastructure, depolarization of the mitochondrial membrane potential (MMP, ??m) and caspase activation. Moreover, fucoidan led to altered expression of factors related to apoptosis, including downregulating Livin and XIAP mRNA, which are members of the inhibitor of apoptotic protein (IAP) family, and increased the Bax-to-Bcl-2 ratio. These findings suggest that fucoidan isolated from U. pinnatifida induced apoptosis in SMMC-7721 cells via the ROS-mediated mitochondrial pathway.

Lili Yang; Peisheng Wang; Huaxin Wang; Qiaomei Li; Hongming Teng; Zhichao Liu; Wenbo Yang; Lin Hou; Xiangyang Zou

2013-01-01

74

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

UK PubMed Central (United Kingdom)

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.

Kim JY; An JM; Chung WY; Park KK; Hwang JK; Kim du S; Seo SR; Seo JT

2013-04-01

75

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

Science.gov (United States)

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

2012-05-25

76

Induction of miR-21-PDCD4 signaling by UVB in JB6 cells involves ROS-mediated MAPK pathways.  

UK PubMed Central (United Kingdom)

Ultraviolet (UV) irradiation plays a major role in the development of human skin cancer. The present study examined the alterations of miR-21-PDCD4 signaling in a mouse epidermal cell line (JB6 P(+)) post exposure to UVB irradiation. The results showed that (1) UVB caused PDCD4 inhibition in JB6 cells; (2) exposure of cells to UVB caused a significant increase of miR-21, the upstream regulator of PDCD4, expression; (3) both inhibition of ERKs with U0126 and inhibition of p38 with SB203580 significantly reversed UVB-induced PDCD4 inhibition; (4) ROS scavenger, N-acetyl-l-cysteine reversed the inhibitory effect of UVB on PDCD4 expression. The above results suggested that UVB induced PDCD4 inhibition, which may be mediated through ROS, especially endogenous H2O2 and p38 and ERKs phosphorylation. Unraveling the complex mechanisms associated with these events may provide insights into the initiation and progression of UVB-induced carcinogenesis.

Hou L; Bowman L; Meighan TG; Pratheeshkumar P; Shi X; Ding M

2013-07-01

77

A rapid and transient ROS generation by cadmium triggers apoptosis via caspase-dependent pathway in HepG2 cells and this is inhibited through N-acetylcysteine-mediated catalase upregulation  

International Nuclear Information System (INIS)

Although reactive oxygen species (ROS) have been implicated in cadmium (Cd)-induced hepatotoxicity, the role of ROS in this pathway remains unclear. Therefore, we attempted to determine the molecular mechanisms relevant to Cd-induced cell death in HepG2 cells. Cd was found to induce apoptosis in the HepG2 cells in a time- and dose-dependent fashion, as confirmed by DNA fragmentation analysis and TUNEL staining. In the early stages, both rapid and transient ROS generation triggered apoptosis via Fas activation and subsequent caspase-8-dependent Bid cleavage, as well as by calpain-mediated mitochondrial Bax cleavage. The timing of Bid activation was coincided with the timing at which the mitochondrial transmembrane potential (MMP) collapsed as well as the cytochrome c (Cyt c) released into the cytosol. Furthermore, mitochondrial permeability transition (MPT) pore inhibitors, such as cyclosporin A (CsA) and bongkrekic acid (BA), did not block Cd-induced ROS generation, MMP collapse and Cyt c release. N-acetylcysteine (NAC) pretreatment resulted in the complete inhibition of the Cd-induced apoptosis via catalase upregulation and subsequent Fas downregulation. NAC treatment also completely blocked the Cd-induced intracellular ROS generation, MMP collapse and Cyt c release, indicating that Cd-induced mitochondrial dysfunction may be regulated indirectly by ROS-mediated signaling pathway. Taken together, a rapid and transient ROS generation by Cd triggers apoptosis via caspase-dependent pathway and subsequent mitochondrial pathway. NAC inhibits Cd-induced apoptosis through the blocking of ROS generation as well as the catalase upregulation

2006-05-01

78

ROS-mediated decline in maximum Ca2+-activated force in rat skeletal muscle fibers following in vitro and in vivo stimulation.  

Science.gov (United States)

We hypothesised that normal skeletal muscle stimulated intensely either in vitro or in situ would exhibit reactive oxygen species (ROS)-mediated contractile apparatus changes common to many pathophysiological conditions. Isolated soleus (SOL) and extensor digitorum longus (EDL) muscles of the rat were bubbled with 95% O(2) and stimulated in vitro at 31°C to give isometric tetani (50 Hz for 0.5 s every 2 s) until maximum force declined to ?30%. Skinned superficial slow-twitch fibers from the SOL muscles displayed a large reduction (?41%) in maximum Ca(2+)-activated specific force (F(max)), with Ca(2+)-sensitivity unchanged. Fibers from EDL muscles were less affected. The decrease in F(max) in SOL fibers was evidently due to oxidation effects on cysteine residues because it was reversed if the reducing agent DTT was applied prior to activating the fiber. The GSH:GSSG ratio was ?3-fold lower in the cytoplasm of superficial fibers from stimulated muscle compared to control, confirming increased oxidant levels. The presence of Tempol and L-NAME during in vitro stimulation prevented reduction in F(max). Skinned fibers from SOL muscles stimulated in vivo at 37°C with intact blood supply also displayed reduction in F(max), though to a much smaller extent (?12%). Thus, fibers from muscles stimulated even with putatively adequate O(2) supply display a reversible oxidation-induced decrease in F(max) without change in Ca(2+)-sensitivity, consistent with action of peroxynitrite (or possibly superoxide) on cysteine residues of the contractile apparatus. Significantly, the changes closely resemble the contractile deficits observed in a range of pathophysiological conditions. These findings highlight how readily muscle experiences ROS-related deficits, and also point to potential difficulties when defining muscle performance and fatigue. PMID:22629297

Dutka, Travis L; Verburg, Esther; Larkins, Noni; Hortemo, Kristin H; Lunde, Per K; Sejersted, Ole M; Lamb, Graham D

2012-05-22

79

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.  

UK PubMed Central (United Kingdom)

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.

Luo M; Liu X; Zu Y; Fu Y; Zhang S; Yao L; Efferth T

2010-10-01

80

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.  

Science.gov (United States)

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

2010-07-16

 
 
 
 
81

ROS-mediated decline in maximum Ca2+-activated force in rat skeletal muscle fibers following in vitro and in vivo stimulation.  

UK PubMed Central (United Kingdom)

We hypothesised that normal skeletal muscle stimulated intensely either in vitro or in situ would exhibit reactive oxygen species (ROS)-mediated contractile apparatus changes common to many pathophysiological conditions. Isolated soleus (SOL) and extensor digitorum longus (EDL) muscles of the rat were bubbled with 95% O(2) and stimulated in vitro at 31°C to give isometric tetani (50 Hz for 0.5 s every 2 s) until maximum force declined to ?30%. Skinned superficial slow-twitch fibers from the SOL muscles displayed a large reduction (?41%) in maximum Ca(2+)-activated specific force (F(max)), with Ca(2+)-sensitivity unchanged. Fibers from EDL muscles were less affected. The decrease in F(max) in SOL fibers was evidently due to oxidation effects on cysteine residues because it was reversed if the reducing agent DTT was applied prior to activating the fiber. The GSH:GSSG ratio was ?3-fold lower in the cytoplasm of superficial fibers from stimulated muscle compared to control, confirming increased oxidant levels. The presence of Tempol and L-NAME during in vitro stimulation prevented reduction in F(max). Skinned fibers from SOL muscles stimulated in vivo at 37°C with intact blood supply also displayed reduction in F(max), though to a much smaller extent (?12%). Thus, fibers from muscles stimulated even with putatively adequate O(2) supply display a reversible oxidation-induced decrease in F(max) without change in Ca(2+)-sensitivity, consistent with action of peroxynitrite (or possibly superoxide) on cysteine residues of the contractile apparatus. Significantly, the changes closely resemble the contractile deficits observed in a range of pathophysiological conditions. These findings highlight how readily muscle experiences ROS-related deficits, and also point to potential difficulties when defining muscle performance and fatigue.

Dutka TL; Verburg E; Larkins N; Hortemo KH; Lunde PK; Sejersted OM; Lamb GD

2012-01-01

82

The reversal of cisplatin-induced nephrotoxicity by selenium nanoparticles functionalized with 11-mercapto-1-undecanol by inhibition of ROS-mediated apoptosis.  

UK PubMed Central (United Kingdom)

Although cisplatin is still one of the most effective chemotherapy agents for human cancers, its clinical use is limited by serious side effects, especially nephrotoxicity. Oxidative stress is an important mediator of cisplatin-induced nephrotoxicity. In the present study, a simple method for functionalization of selenium nanoparticles by self-assembly of 11-mercapto-1-undecanol (Se@MUN) to achieve enhanced antioxidant activity and antagonis against cisplatin-induced nephrotoxicity has been demonstrated. The chemical structure of the nanoparticles was characterized by various microscopic and spectroscopic methods. The results revealed that the spherical nanoparticles were capped with MUN on the surface through formation of Se-S bond. The in vitro protective effects of Se@MUN on HK-2 proximal tubular cells against cisplatin-induced nephrotoxicity and the underlying mechanisms were also investigated. Se@MUN exhibited free radical scavenging activity and higher cellular uptake in human normal cells by comparing with SeNPs. Se@MUN significantly attenuated cisplatin-induced reduction in cell viability, appearance of Sub-G1 peak, nuclear condensation and DNA fragmentation in HK-2 cells. Activation of caspase-3 in cells exposed to cisplatin was also effectively blocked by Se@MUN. Moreover, Se@MUN significantly prevented the cisplatin-induced overproduction of intracellular ROS. Our findings suggest that Se@MUN is a promising selenium species with potential application in prevention of cisplatin-induced renal injury.

Li Y; Li X; Wong YS; Chen T; Zhang H; Liu C; Zheng W

2011-12-01

83

The reversal of cisplatin-induced nephrotoxicity by selenium nanoparticles functionalized with 11-mercapto-1-undecanol by inhibition of ROS-mediated apoptosis.  

Science.gov (United States)

Although cisplatin is still one of the most effective chemotherapy agents for human cancers, its clinical use is limited by serious side effects, especially nephrotoxicity. Oxidative stress is an important mediator of cisplatin-induced nephrotoxicity. In the present study, a simple method for functionalization of selenium nanoparticles by self-assembly of 11-mercapto-1-undecanol (Se@MUN) to achieve enhanced antioxidant activity and antagonis against cisplatin-induced nephrotoxicity has been demonstrated. The chemical structure of the nanoparticles was characterized by various microscopic and spectroscopic methods. The results revealed that the spherical nanoparticles were capped with MUN on the surface through formation of Se-S bond. The in vitro protective effects of Se@MUN on HK-2 proximal tubular cells against cisplatin-induced nephrotoxicity and the underlying mechanisms were also investigated. Se@MUN exhibited free radical scavenging activity and higher cellular uptake in human normal cells by comparing with SeNPs. Se@MUN significantly attenuated cisplatin-induced reduction in cell viability, appearance of Sub-G1 peak, nuclear condensation and DNA fragmentation in HK-2 cells. Activation of caspase-3 in cells exposed to cisplatin was also effectively blocked by Se@MUN. Moreover, Se@MUN significantly prevented the cisplatin-induced overproduction of intracellular ROS. Our findings suggest that Se@MUN is a promising selenium species with potential application in prevention of cisplatin-induced renal injury. PMID:21864903

Li, Yinghua; Li, Xiaoling; Wong, Yum-Shing; Chen, Tianfeng; Zhang, Haobin; Liu, Chaoran; Zheng, Wenjie

2011-08-23

84

RIP1-mediated mitochondrial dysfunction and ROS production contributed to tumor necrosis factor alpha-induced L929 cell necroptosis and autophagy.  

Science.gov (United States)

Tumor necrosis factor alpha (TNF?) induces necroptosis and autophagy; however, the detailed molecular mechanism is not fully understood. In this study, we found that TNF? administration caused mitochondrial dysfunction and reactive oxygen species (ROS) production, which led to necroptosis and autophagy in murine fibrosarcoma L929 cells. Notably, the RIP1 (serine-threonine kinase receptor-interacting protein 1, a main adaptor protein of necroptosis) specific inhibitor necrostatin-1 (Nec-1) recovered mitochondrial dysfunction and ROS production due to TNF? administration. Moreover, pan-caspase inhibitor z-VAD-fmk (zVAD) increased RIP1 expression and exacerbated TNF?-induced mitochondrial dysfunction and ROS production, indicating that RIP1 led to mitochondrial dysfunction and ROS production. In addition, cytochrome c release from mitochondria was accompanied with TNF? administration, and Nec-1 blocked the release of cytochrome c upon TNF? administration, while zVAD enhanced the release. These further suggested that RIP1 induced mitochondrial dysfunction accompanied with cytochrome c release. Furthermore, autophagy inhibitor 3-methyladenine (3MA) did not affect RIP1 expression as well as mitochondrial dysfunction and ROS production. Together with our previous publication that autophagy was a downstream consequence of necroptosis, we concluded that TNF? induced mitochondrial dysfunction accompanied with ROS production and cytochrome c release via RIP1, leading to necroptosis and resulting autophagic cell death. PMID:23000518

Ye, Yuan-Chao; Wang, Hong-Ju; Yu, Lu; Tashiro, Shin-Ichi; Onodera, Satoshi; Ikejima, Takashi

2012-09-20

85

RIP1-mediated mitochondrial dysfunction and ROS production contributed to tumor necrosis factor alpha-induced L929 cell necroptosis and autophagy.  

UK PubMed Central (United Kingdom)

Tumor necrosis factor alpha (TNF?) induces necroptosis and autophagy; however, the detailed molecular mechanism is not fully understood. In this study, we found that TNF? administration caused mitochondrial dysfunction and reactive oxygen species (ROS) production, which led to necroptosis and autophagy in murine fibrosarcoma L929 cells. Notably, the RIP1 (serine-threonine kinase receptor-interacting protein 1, a main adaptor protein of necroptosis) specific inhibitor necrostatin-1 (Nec-1) recovered mitochondrial dysfunction and ROS production due to TNF? administration. Moreover, pan-caspase inhibitor z-VAD-fmk (zVAD) increased RIP1 expression and exacerbated TNF?-induced mitochondrial dysfunction and ROS production, indicating that RIP1 led to mitochondrial dysfunction and ROS production. In addition, cytochrome c release from mitochondria was accompanied with TNF? administration, and Nec-1 blocked the release of cytochrome c upon TNF? administration, while zVAD enhanced the release. These further suggested that RIP1 induced mitochondrial dysfunction accompanied with cytochrome c release. Furthermore, autophagy inhibitor 3-methyladenine (3MA) did not affect RIP1 expression as well as mitochondrial dysfunction and ROS production. Together with our previous publication that autophagy was a downstream consequence of necroptosis, we concluded that TNF? induced mitochondrial dysfunction accompanied with ROS production and cytochrome c release via RIP1, leading to necroptosis and resulting autophagic cell death.

Ye YC; Wang HJ; Yu L; Tashiro S; Onodera S; Ikejima T

2012-12-01

86

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

UK PubMed Central (United Kingdom)

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.

Kovácik J; Klejdus B; Backor M

2009-06-01

87

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

2009-04-01

88

Pseudomonas aeruginosa Pyocyanin Activates NRF2-ARE-Mediated Transcriptional Response via the ROS-EGFR-PI3K-AKT/MEK-ERK MAP Kinase Signaling in Pulmonary Epithelial Cells.  

UK PubMed Central (United Kingdom)

The redox-active pyocyanin (PCN) secreted by the respiratory pathogen Pseudomonas aeruginosa generates reactive oxygen species (ROS) and causes oxidative stress to pulmonary epithelial cells. Nuclear factor (erythroid-derived 2)-like 2 (NRF2) confers protection against ROS-mediated cell death by inducing the expression of detoxifying enzymes and proteins via its binding to the cis-acting antioxidant response element (ARE). However, a clear relationship between NRF2 and PCN-mediated oxidative stress has not been established experimentally. In this study, we investigated the induction of NRF2-ARE response by PCN in the pulmonary epithelial cells. We analyzed the effect of PCN on NRF2 expression and nuclear translocation in cultured human airway epithelial cells, and in a mouse model of chronic PCN exposure. NRF2-dependent transcription of antioxidative enzymes was also assessed. Furthermore, we used inhibitors to examine the involvement of EGFR and its downstream signaling components that mediate NRF2-ARE-activation in response to PCN. PCN enhances the nuclear NRF2 accumulation and activates the transcription of ARE-mediated antioxidant genes. Furthermore, PCN activates NRF2 by inducing the EGFR-phosphoinositide-3-kinase (PI3K) signaling pathway and its main downstream effectors, AKT and MEK1/2-ERK1/2 MAP kinases. Inhibition of the EGFR-PI3K signaling markedly attenuates PCN-stimulated NRF2 accumulation in the nucleus. We demonstrate for the first time that PCN-mediated oxidative stress activates the EGFR-PI3K-AKT/MEK1/2-ERK1/2 MAP kinase signaling pathway, leading to nuclear NRF2 translocation and ARE responsiveness in pulmonary epithelial cells.

Xu Y; Duan C; Kuang Z; Hao Y; Jeffries JL; Lau GW

2013-01-01

89

Pseudomonas aeruginosa Pyocyanin Activates NRF2-ARE-Mediated Transcriptional Response via the ROS-EGFR-PI3K-AKT/MEK-ERK MAP Kinase Signaling in Pulmonary Epithelial Cells.  

Science.gov (United States)

The redox-active pyocyanin (PCN) secreted by the respiratory pathogen Pseudomonas aeruginosa generates reactive oxygen species (ROS) and causes oxidative stress to pulmonary epithelial cells. Nuclear factor (erythroid-derived 2)-like 2 (NRF2) confers protection against ROS-mediated cell death by inducing the expression of detoxifying enzymes and proteins via its binding to the cis-acting antioxidant response element (ARE). However, a clear relationship between NRF2 and PCN-mediated oxidative stress has not been established experimentally. In this study, we investigated the induction of NRF2-ARE response by PCN in the pulmonary epithelial cells. We analyzed the effect of PCN on NRF2 expression and nuclear translocation in cultured human airway epithelial cells, and in a mouse model of chronic PCN exposure. NRF2-dependent transcription of antioxidative enzymes was also assessed. Furthermore, we used inhibitors to examine the involvement of EGFR and its downstream signaling components that mediate NRF2-ARE-activation in response to PCN. PCN enhances the nuclear NRF2 accumulation and activates the transcription of ARE-mediated antioxidant genes. Furthermore, PCN activates NRF2 by inducing the EGFR-phosphoinositide-3-kinase (PI3K) signaling pathway and its main downstream effectors, AKT and MEK1/2-ERK1/2 MAP kinases. Inhibition of the EGFR-PI3K signaling markedly attenuates PCN-stimulated NRF2 accumulation in the nucleus. We demonstrate for the first time that PCN-mediated oxidative stress activates the EGFR-PI3K-AKT/MEK1/2-ERK1/2 MAP kinase signaling pathway, leading to nuclear NRF2 translocation and ARE responsiveness in pulmonary epithelial cells. PMID:24015256

Xu, Ying; Duan, Chaohui; Kuang, Zhizhou; Hao, Yonghua; Jeffries, Jayme L; Lau, Gee W

2013-08-27

90

ATP mediates NADPH oxidase/ROS generation and COX-2/PGE2 expression in A549 cells: role of P2 receptor-dependent STAT3 activation.  

UK PubMed Central (United Kingdom)

BACKGROUND: Up-regulation of cyclooxygenase (COX)-2 and its metabolite prostaglandin E(2) (PGE(2)) are frequently implicated in lung inflammation. Extracellular nucleotides, such as ATP have been shown to act via activation of P2 purinoceptors, leading to COX-2 expression in various inflammatory diseases, such as lung inflammation. However, the mechanisms underlying ATP-induced COX-2 expression and PGE(2) release remain unclear. PRINCIPAL FINDINGS: Here, we showed that ATP?S induced COX-2 expression in A549 cells revealed by western blot and real-time PCR. Pretreatment with the inhibitors of P2 receptor (PPADS and suramin), PKC (Gö6983, Gö6976, Ro318220, and Rottlerin), ROS (Edaravone), NADPH oxidase [diphenyleneiodonium chloride (DPI) and apocynin], Jak2 (AG490), and STAT3 [cucurbitacin E (CBE)] and transfection with siRNAs of PKC?, PKC?, PKC?, p47(phox), Jak2, STAT3, and cPLA(2) markedly reduced ATP?S-induced COX-2 expression and PGE(2) production. In addition, pretreatment with the inhibitors of P2 receptor attenuated PKCs translocation from the cytosol to the membrane in response to ATP?S. Moreover, ATP?S-induced ROS generation and p47(phox) translocation was also reduced by pretreatment with the inhibitors of P2 receptor, PKC, and NADPH oxidase. On the other hand, ATP?S stimulated Jak2 and STAT3 activation which were inhibited by pretreatment with PPADS, suramin, Gö6983, Gö6976, Ro318220, GF109203X, Rottlerin, Edaravone, DPI, and apocynin in A549 cells. SIGNIFICANCE: Taken together, these results showed that ATP?S induced COX-2 expression and PGE(2) production via a P2 receptor/PKC/NADPH oxidase/ROS/Jak2/STAT3/cPLA(2) signaling pathway in A549 cells. Increased understanding of signal transduction mechanisms underlying COX-2 gene regulation will create opportunities for the development of anti-inflammation therapeutic strategies.

Cheng SE; Lee IT; Lin CC; Wu WL; Hsiao LD; Yang CM

2013-01-01

91

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

92

A ROS-mediated lysosomal-mitochondrial pathway is induced by a novel Amonafide analogue, 7c, in human Hela cervix carcinoma cells.  

UK PubMed Central (United Kingdom)

In this study, a novel naphthalimide derivative 7c was designed which is topo II inhibiting though owning weak DNA binders. It was shown that 7c could induce cancer cells apoptosis and have less cytotoxicity in normal human cell. Further investigations on Hela cells revealed that 7c could also induce ROS generation, lysosome rupture as well as cathepsin B release. Subsequent mitochondrial damages including mitochondrial membrane permeabilization and the release of cytochrome c were also found in 7c when treating with Hela cells. According to our data, 7c may act as a lead compound for potential anticancer drugs. The idea of naphthalimides modification may also provide a novel strategy for naphthalimides design.

Shen K; Sun L; Zhang H; Xu Y; Qian X; Lu Y; Li Q; Ni L; Liu J

2013-06-01

93

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

94

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.

95

Benzyl isothiocyanate (BITC) induces G2/M phase arrest and apoptosis in human melanoma A375.S2 cells through reactive oxygen species (ROS) and both mitochondria-dependent and death receptor-mediated multiple signaling pathways.  

UK PubMed Central (United Kingdom)

Benzyl isothiocyanates (BITC), a member of the isothiocyanate (ITC) family, inhibits cell growth and induces apoptosis in many types of human cancer cell lines. The present study investigated mechanisms underlying BITC-induced apoptosis in A375.S2 human melanoma cancer cells. To observe cell morphological changes and viability, flow cytometric assays, cell counting, and a contrast-phase microscopic examination were carried out in A375.S2 cells after BITC treatment. Cell cycle distribution and apoptosis were assessed with the analysis of cell cycle by flow cytometric assays, DAPI staining, propidium iodide (PI), and annexin V staining. Apoptosis-associated factors such as reactive oxygen species (ROS) formation, loss of mitochondrial membrane potential (??(m)), intracellular Ca(2+) release, and caspase-3 activity were evaluated by flow cytometric assays. Abundance of cell cycle and apoptosis associated proteins was determined by Western blotting. AIF and Endo G expression was examined by confocal laser microscope. Results indicated that (1) BITC significantly reduced cell number and induced cell morphological changes in a dose-dependent manner in A375.S2 cells; (2) BITC induced arrest in cell cycle progression at G(2)/M phase through cyclin A, CDK1, CDC25C/Wee1-mediated pathways; (3) BITC induced apoptosis and increased sub-G(1) population; and (4) BITC promoted the production of ROS and Ca(2+) and loss of ??(m) and caspase-3 activity. Furthermore, BITC induced the down-regulation of Bcl-2 expression and induced up-regulation of Bax in A375.S2 cells. Moreover, BITC-induced cell death was decreased after pretreatment with N-acetyl-l-cysteine (NAC, a ROS scavenger) in A375.S2 cells. In conclusion, the results showed that BITC promoted the induction of G(2)/M phase arrest and apoptosis in A375.S2 human melanoma cells through ER stress- and mitochondria-dependent and death receptor-mediated multiple signaling pathways. These data suggest that BITC has potential as an agent for the treatment of melanoma.

Huang SH; Wu LW; Huang AC; Yu CC; Lien JC; Huang YP; Yang JS; Yang JH; Hsiao YP; Wood WG; Yu CS; Chung JG

2012-01-01

96

The protective role of arjunolic acid against doxorubicin induced intracellular ROS dependent JNK-p38 and p53-mediated cardiac apoptosis.  

Science.gov (United States)

In spite of tremendous demand for the development and implementation of effective therapeutic strategies, limitations are still associated with doxorubicin-induced cardiotoxicity. Arjunolic acid (AA) has been shown to possess a multitude of biological functions. The purpose of the present study was to explore whether AA plays any protective role against doxorubicin-induced cardiotoxicity; and if so, what molecular mechanism it utilizes for its protective action. In rat cardiomyocytes, doxorubicin administration activated the proapoptotic p53, p38 and JNK MAPKs, Bax translocation, disrupted mitochondrial membrane potential, precipitated mitochondrion mediated caspase-dependent apoptotic signalling and reduced viability of cardiomyocytes. Doxorubicin exposure increases dichlorofluorescein (DCF) intensity corresponding to the intracellular H(2)O(2) generation in myocytes; catalase (CAT) treatment, however, reduced this intensity and preserves cell viability. Intracellular H(2)O(2) thus produced now activates the p38-JNK and p53-mediated pathways. CAT treatment also markedly decreased the doxorubicin-mediated activation of p38 and JNK, suggesting that H(2)O(2) is involved in the activation of MAPKs. Blockage of p53 and p38-JNK by pharmacological inhibitors also suppressed the doxorubicin-induced apoptosis with the concomitant inhibition of anti-apoptotic Bcl-2 family proteins. AA treatment ameliorates nearly all of these apoptotic actions of doxorubicin and preserves cell viability. Similarly, rats treated with doxorubicin displayed retarded growth of body and heart as well as elevated apoptotic indices in heart tissue, whereas AA treatment effectively neutralised all these doxorubicin-induced cardiac-abnormalities. Combining all, our results suggest that doxorubicin induces cardiac apoptosis via the activation of JNK-p38 and p53-mediated signalling pathways, where H(2)O(2) acts as the mediators of these pathways. AA can effectively and extensively counteract this action of doxorubicin, and may potentially protect the heart and cardiomyocytes from the severe doxorubicin-induced cardiovascular burden. PMID:21486680

Ghosh, Jyotirmoy; Das, Joydeep; Manna, Prasenjit; Sil, Parames C

2011-04-12

97

The protective role of arjunolic acid against doxorubicin induced intracellular ROS dependent JNK-p38 and p53-mediated cardiac apoptosis.  

UK PubMed Central (United Kingdom)

In spite of tremendous demand for the development and implementation of effective therapeutic strategies, limitations are still associated with doxorubicin-induced cardiotoxicity. Arjunolic acid (AA) has been shown to possess a multitude of biological functions. The purpose of the present study was to explore whether AA plays any protective role against doxorubicin-induced cardiotoxicity; and if so, what molecular mechanism it utilizes for its protective action. In rat cardiomyocytes, doxorubicin administration activated the proapoptotic p53, p38 and JNK MAPKs, Bax translocation, disrupted mitochondrial membrane potential, precipitated mitochondrion mediated caspase-dependent apoptotic signalling and reduced viability of cardiomyocytes. Doxorubicin exposure increases dichlorofluorescein (DCF) intensity corresponding to the intracellular H(2)O(2) generation in myocytes; catalase (CAT) treatment, however, reduced this intensity and preserves cell viability. Intracellular H(2)O(2) thus produced now activates the p38-JNK and p53-mediated pathways. CAT treatment also markedly decreased the doxorubicin-mediated activation of p38 and JNK, suggesting that H(2)O(2) is involved in the activation of MAPKs. Blockage of p53 and p38-JNK by pharmacological inhibitors also suppressed the doxorubicin-induced apoptosis with the concomitant inhibition of anti-apoptotic Bcl-2 family proteins. AA treatment ameliorates nearly all of these apoptotic actions of doxorubicin and preserves cell viability. Similarly, rats treated with doxorubicin displayed retarded growth of body and heart as well as elevated apoptotic indices in heart tissue, whereas AA treatment effectively neutralised all these doxorubicin-induced cardiac-abnormalities. Combining all, our results suggest that doxorubicin induces cardiac apoptosis via the activation of JNK-p38 and p53-mediated signalling pathways, where H(2)O(2) acts as the mediators of these pathways. AA can effectively and extensively counteract this action of doxorubicin, and may potentially protect the heart and cardiomyocytes from the severe doxorubicin-induced cardiovascular burden.

Ghosh J; Das J; Manna P; Sil PC

2011-07-01

98

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

UK PubMed Central (United Kingdom)

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.

Park KR; Nam D; Yun HM; Lee SG; Jang HJ; Sethi G; Cho SK; Ahn KS

2011-12-01

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

2011-08-26

100

AGE, RAGE, and ROS in diabetic nephropathy.  

UK PubMed Central (United Kingdom)

Diabetic nephropathy is a major cause of morbidity and mortality in diabetic patients. Two key mechanisms implicated in the development of diabetic nephropathy include advanced glycation and oxidative stress. Advanced glycation is the irreversible attachment of reducing sugars onto amino groups of proteins to form advanced glycation end products (AGEs). AGE modification of proteins may lead to alterations in normal function by inducing cross-linking of extracellular matrices. Intracellular formation of AGEs also can cause generalized cellular dysfunction. Furthermore, AGEs can mediate their effects via specific receptors, such as the receptor for AGE (RAGE), activating diverse signal transduction cascades and downstream pathways, including generation of reactive oxygen species (ROS). Oxidative stress occurs as a result of the imbalance between ROS production and antioxidant defenses. Sources of ROS include the mitochondria, auto-oxidation of glucose, and enzymatic pathways including nicotinamide adenine dinucleotide phosphate reduced (NAD[P]H) oxidase. Beyond the current treatments to treat diabetic complications such as the optimization of blood pressure and glycemic control, it is predicted that new therapies designed to target AGEs, including AGE formation inhibitors and cross-link breakers, as well as targeting ROS using novel highly specific antioxidants, will become part of the treatment regimen for diabetic renal disease.

Tan AL; Forbes JM; Cooper ME

2007-03-01

 
 
 
 
101

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

102

Learning ROS for robotics programming  

CERN Multimedia

The book will take an easy-to-follow and engaging tutorial approach, providing a practical and comprehensive way to learn ROS.If you are a robotic enthusiast who wants to learn how to build and program your own robots in an easy-to-develop, maintainable and shareable way, ""Learning ROS for Robotics Programming"" is for you. In order to make the most of the book, you should have some C++ programming background, knowledge of GNU/Linux systems, and computer science in general. No previous background on ROS is required, since this book provides all the skills required. It is also advisable to hav

Martinez, Aaron

2013-01-01

103

A reaction-diffusion model of ROS-induced ROS release in a mitochondrial network.  

Science.gov (United States)

Loss of mitochondrial function is a fundamental determinant of cell injury and death. In heart cells under metabolic stress, we have previously described how the abrupt collapse or oscillation of the mitochondrial energy state is synchronized across the mitochondrial network by local interactions dependent upon reactive oxygen species (ROS). Here, we develop a mathematical model of ROS-induced ROS release (RIRR) based on reaction-diffusion (RD-RIRR) in one- and two-dimensional mitochondrial networks. The nodes of the RD-RIRR network are comprised of models of individual mitochondria that include a mechanism of ROS-dependent oscillation based on the interplay between ROS production, transport, and scavenging; and incorporating the tricarboxylic acid (TCA) cycle, oxidative phosphorylation, and Ca(2+) handling. Local mitochondrial interaction is mediated by superoxide (O2.-) diffusion and the O2.(-)-dependent activation of an inner membrane anion channel (IMAC). In a 2D network composed of 500 mitochondria, model simulations reveal DeltaPsi(m) depolarization waves similar to those observed when isolated guinea pig cardiomyocytes are subjected to a localized laser-flash or antioxidant depletion. The sensitivity of the propagation rate of the depolarization wave to O(2.-) diffusion, production, and scavenging in the reaction-diffusion model is similar to that observed experimentally. In addition, we present novel experimental evidence, obtained in permeabilized cardiomyocytes, confirming that DeltaPsi(m) depolarization is mediated specifically by O2.-). The present work demonstrates that the observed emergent macroscopic properties of the mitochondrial network can be reproduced in a reaction-diffusion model of RIRR. Moreover, the findings have uncovered a novel aspect of the synchronization mechanism, which is that clusters of mitochondria that are oscillating can entrain mitochondria that would otherwise display stable dynamics. The work identifies the fundamental mechanisms leading from the failure of individual organelles to the whole cell, thus it has important implications for understanding cell death during the progression of heart disease. PMID:20126535

Zhou, Lufang; Aon, Miguel A; Almas, Tabish; Cortassa, Sonia; Winslow, Raimond L; O'Rourke, Brian

2010-01-29

104

Gravitropic response induced by coumarin: Evidences of ROS distribution involvement.  

UK PubMed Central (United Kingdom)

Coumarin effects on gravitropic responses of Arabidopsis thaliana roots were here evaluated. Coumarin alone did not cause any alteration on gravitropic response showing a behavior similar to control plants. In contrast, TIBA and NPA, two auxin transport inhibitors, strongly modified root gravitropic responses. The addition of coumarin to the medium together with TIBA or NPA partially restored the effect of both inhibitors. Simultaneously, a semi-quantitative evaluation of ROS distribution was performed on root tips. TIBA and NPA caused a wide distribution of O 2 (-) , ROS oxidant species, around the root tip which disappeared with coumarin addition to both treatments, restoring ROS localized distribution. These results indicated a strong correlation between ROS distribution and coumarin-mediated recovery of root gravitropism.

Lupini A; Araniti F; Sunseri F; Abenavoli MR

2013-01-01

105

Effect of electroacupuncture to prevent selenite-induced cataract in Wistar rats/ Efeito da eletro-acupuntura na prevenção da catarata induzida por selenito de sódio em ratos Wistar  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese OBJETIVO: Avaliar o efeito da eletro-acupuntura na prevenção da catarata induzida por selenito de sódio em modelo experimental. MÉTODO: Cinqüenta filhotes de ratos Wistar foram randomizados em 5 grupos: no Grupo 1 (Controle, n=10) nenhum procedimento foi realizado. Grupo 2 (Selenito, n=10), selenito de sódio (30 µmoles/kg) foi injetado por via subcutânea no décimo dia de vida. No Grupo 3 (Anestesia, n=10), filhotes receberam a mesma dose de selenito e sofreram an (more) estesia inalatória com éter etílico durante 10 minutos diariamente por 1 semana. Grupo 4 (eletro-acupuntura, n=10), os animais sofreram os mesmos procedimentos do Grupo 3, porém também receberam eletro-acupuntura (2 Hz, 50 mA) aplicada nos pontos Neiguan (PC 6) e Guangming (GB37) durante o período de anestesia. Grupo 5 (Sham, n=10), os ratos foram submetidos aos mesmos procedimentos que o Grupo 4, porém as agulhas foram aplicadas em pontos falsos. O desenvolvimento da catarata foi avaliado após uma semana por lâmpada de fenda. RESULTADOS: Todos os animais controles (Grupo 1) não desenvolveram catarata. Todos os ratos dos grupos 2, 3 e 5 desenvolveram catarata grave. No Grupo 4 (eletro-acupuntura), 45% dos olhos não desenvolveram catarata e trinta por cento desenvolveram catarata menos grave que aos Grupos 2, 3 e 5. A diferença entre os grupos foi estatisticamente significante (p Abstract in english PURPOSE: To investigate whether electroacupuncture can prevent selenite-induced cataract in an experimental model. METHODS: Fifty Wistar rat pups were randomized into 5 groups of 10 animals: Group 1 (control), no procedure was performed; Group 2 (selenite), sodium selenite (30 micromoles/kg body weight) was injected subcutaneously between postpartum days 10 to 12; Group 3 (anesthesia) received the same dose of selenite and underwent ether inhalation anesthesia during 10 m (more) inutes daily for one week; Group 4 (electroacupuncture) underwent the same procedure of Group 3, but also receiving electroacupuncture (2 Hz, 50 mA) applied to the Neiguan (PC6) and Guangming (GB37) acupoints during the anesthesia period; and Group 5 (Sham) underwent the same procedures of Group 4, but needles were applied to non-acupoints. The development of cataract was assessed one week later, and its density was graded by slit lamp biomicroscopy. RESULTS: All control rats lenses (Group 1) were clear. Groups 2, 3 and 5 rats developed more severe cataract or complete opacification. In Group 4 (electroacupuncture), 45% of eyes did not develop cataract while thirty per cent developed less severe cataract than Groups 2, 3 and 5. The between-group difference was statistically significant (p

Cariello, Angelino Julio; Casanova, Fábio Henrique; Lima Filho, Acácio Alves de Souza; Juliano, Yara; Tabosa, Angela

2006-06-01

106

The redox-sensitive cation channel TRPM2 modulates phagocyte ROS production and inflammation  

Science.gov (United States)

The NADPH oxidase activity of phagocytes and its generation of reactive oxygen species (ROS) is critical for host-defense, but ROS overproduction can also lead to inflammation and tissue injury. Here we report that TRPM2, a non-selective and redox-sensitive cation channel, inhibits ROS production in phagocytic cells and prevents endotoxin-induced lung inflammation in mice. TRPM2-deficient mice challenged with endotoxin (lipopolysaccharide) showed an increased inflammatory signature and decreased survival compared to controls. TRPM2 functions by dampening NADPH oxidase-mediated ROS production through depolarization of the plasma membrane in phagocytes. Since ROS also activates TRPM2, our findings establish a negative feedback mechanism inactivating ROS production through inhibition of the membrane potential-sensitive NADPH oxidase.

Di, Anke; Gao, Xiao-Pei; Qian, Feng; Kawamura, Takeshi; Han, Jin; Hecquet, Claudie; Ye, Richard D.; Vogel, Stephen M.; Malik, Asrar B.

2011-01-01

107

Effect of electroacupuncture to prevent selenite-induced cataract in Wistar rats Efeito da eletro-acupuntura na prevenção da catarata induzida por selenito de sódio em ratos Wistar  

Directory of Open Access Journals (Sweden)

Full Text Available PURPOSE: To investigate whether electroacupuncture can prevent selenite-induced cataract in an experimental model. METHODS: Fifty Wistar rat pups were randomized into 5 groups of 10 animals: Group 1 (control), no procedure was performed; Group 2 (selenite), sodium selenite (30 micromoles/kg body weight) was injected subcutaneously between postpartum days 10 to 12; Group 3 (anesthesia) received the same dose of selenite and underwent ether inhalation anesthesia during 10 minutes daily for one week; Group 4 (electroacupuncture) underwent the same procedure of Group 3, but also receiving electroacupuncture (2 Hz, 50 mA) applied to the Neiguan (PC6) and Guangming (GB37) acupoints during the anesthesia period; and Group 5 (Sham) underwent the same procedures of Group 4, but needles were applied to non-acupoints. The development of cataract was assessed one week later, and its density was graded by slit lamp biomicroscopy. RESULTS: All control rats lenses (Group 1) were clear. Groups 2, 3 and 5 rats developed more severe cataract or complete opacification. In Group 4 (electroacupuncture), 45% of eyes did not develop cataract while thirty per cent developed less severe cataract than Groups 2, 3 and 5. The between-group difference was statistically significant (pOBJETIVO: Avaliar o efeito da eletro-acupuntura na prevenção da catarata induzida por selenito de sódio em modelo experimental. MÉTODO: Cinqüenta filhotes de ratos Wistar foram randomizados em 5 grupos: no Grupo 1 (Controle, n=10) nenhum procedimento foi realizado. Grupo 2 (Selenito, n=10), selenito de sódio (30 µmoles/kg) foi injetado por via subcutânea no décimo dia de vida. No Grupo 3 (Anestesia, n=10), filhotes receberam a mesma dose de selenito e sofreram anestesia inalatória com éter etílico durante 10 minutos diariamente por 1 semana. Grupo 4 (eletro-acupuntura, n=10), os animais sofreram os mesmos procedimentos do Grupo 3, porém também receberam eletro-acupuntura (2 Hz, 50 mA) aplicada nos pontos Neiguan (PC 6) e Guangming (GB37) durante o período de anestesia. Grupo 5 (Sham, n=10), os ratos foram submetidos aos mesmos procedimentos que o Grupo 4, porém as agulhas foram aplicadas em pontos falsos. O desenvolvimento da catarata foi avaliado após uma semana por lâmpada de fenda. RESULTADOS: Todos os animais controles (Grupo 1) não desenvolveram catarata. Todos os ratos dos grupos 2, 3 e 5 desenvolveram catarata grave. No Grupo 4 (eletro-acupuntura), 45% dos olhos não desenvolveram catarata e trinta por cento desenvolveram catarata menos grave que aos Grupos 2, 3 e 5. A diferença entre os grupos foi estatisticamente significante (p<0,001). A média do grau de opacificação do cristalino nos Grupos 1 e 4 foi mais baixo que nos Grupos 2, 3 e 5 (p<0,001). CONCLUSÃO: Eletro-acupuntura diminuiu a taxa de formação de catarata induzida por selenito em filhotes de ratos quando as agulhas foram aplicadas em pontos de acupuntura específicos.

Angelino Julio Cariello; Fábio Henrique Casanova; Acácio Alves de Souza Lima Filho; Yara Juliano; Angela Tabosa

2006-01-01

108

8-Methly-4-(3-diethylaminopropylamino) pyrimido [4',5';4,5] thieno (2,3-b) quinoline (MDPTQ), a quinoline derivate that causes ROS-mediated apoptosis in leukemia cell lines  

International Nuclear Information System (INIS)

[en] The present study reports the biological activity of 8-methly-4-(3-diethylamino-propylamino) pyrimido [4';5';4,5] thieno (2,3-b) quinoline (MDPTQ), a quinoline derivative structurally related to ellipticine and suggests a possible mechanism through which the compound induces apoptosis in carcinoma cell lines. Out of the 8 cell lines used in the study as representatives of different types of cancer, MDPTQ was found to be effective only against leukemia cell lines (HL-60 and K-562) whereas it had no effect on normal human bone marrow cells (BMC) which were used as controls. Fall mitochondrial membrane potential and increased reactive oxygen species (ROS) were mainly responsible for inducing apoptosis in the two cell lines. Cell death was demonstrated by increase in caspase 3 activity as well as phosphatidyl serine exposure. Pre-incubation with N-acetylcysteine (NAC) reduced the increased ROS and caspase 3 activity as well as phosphatidyl serine exposure. MDPTQ also caused cell cycle arrest in these cell lines. The above study for the first time reports the mode of action of a quinoline derivative, which could be a possible future candidate for leukemia therapy. However, there are lot of questions that need to be answered in terms of signalling pathways and its effects on animal models

2007-07-01

109

Are ROS always detrimental to pathogens?  

UK PubMed Central (United Kingdom)

Significance: Reactive oxygen species (ROS) are deadly weapons, used by phagocytes and other cell types, such as lung epithelial cell, against pathogens. ROS can kill pathogens directly by causing oxidative damage to biocompounds or indirectly, by stimulating pathogen elimination by various non-oxidative mechanisms, including pattern recognition receptors (PRR) signaling, autophagy, NET formation, and T lymphocyte responses. Thus, one should expect that inhibition of ROS production promote infection. Recent advances: Increasing evidences support that in certain particular infections, antioxidants decrease and prooxidants increase pathogen burden. Critical issues: Here, we review the classic infections that are controlled by ROS and the cases in which ROS appear as promoters of infection, challenging the paradigm. We discuss the possible mechanisms by which ROS could promote particular infections. These mechanisms are still not completely clear but include metabolic effects of ROS on pathogen physiology, ROS-induced damage to the immune system, and ROS-induced activation of immune defense mechanisms that are subsequently hijacked by particular pathogens to act against more effective microbicidal mechanisms of the immune system. Future directions: The effective use of antioxidants as therapeutic agents against certain infections is a realistic possibility that is beginning to be applied against viruses.

Paiva CN; Bozza MT

2013-09-01

110

Changes in blood ROS, e-NO, and some pro-inflammatory mediators in bronchial secretions following erdosteine or placebo: a controlled study in current smokers with mild COPD.  

UK PubMed Central (United Kingdom)

Anti-oxidant interventions consist in reduction of direct oxidant damage by removing oxidant agents and/or by supplementing reducing agents with anti-oxidant effects. AIM: Aim of the present study was to investigate the anti-oxidant effects of erdosteine, a recent drug currently used in chronic obstructive pulmonary disease (COPD) for its rheological activity. At present, no data are available on current smokers with COPD to our knowledge. METHODS: Two groups of 10 persons matched for sex; age (65.0 yr+/-8.4 S.D. and 65.3 yr+/-6.5 S.D.); basal FEV1 (88.7% pred +/-6.8 S.D. and 85.2% pred +/-5.8 S.D.); and cigarette consumption (25.4 pack/yr+/-3.5 S.D. and 28.1 pack/yr+/-2.3 S.D.) entered a controlled, double blind, parallel groups study. They were randomized to receive erdosteine 600 mg daily or placebo for 10 days. IL-6; IL-8; TNFalpha were measured in bronchial secretions in bsln, after 4, 7, and 10 days of Erdosteine or placebo; e-NO and both ROS and 8-Isoprostane in blood were also measured at the same experimental times. STATISTICS: ANOVA: a t-test with Bonferroni correction; p<0.05 was accepted. RESULTS: Blood ROS and IL-8 in bronchial secretions dropped significantly following erdosteine starting from day 4 (both p<0.01), while 8-isoprostane drop was significant only after day 10 (p<0.02), and the e-NO decrease proved evident but not significant. No significant changes were observed in the placebo group. CONCLUSIONS: Erdosteine affects substantially some pro-inflammatory cytokines specifically involved in oxidative stress in current smokers with mild COPD. Effects appeared differently time-dependent. Further long-term studies are needed to confirm these pilot data and to assess their long-term clinical relevance.

Dal Negro RW; Visconti M; Micheletto C; Tognella S

2008-01-01

111

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

112

Wnt/?-catenin signaling induces the aging of mesenchymal stem cells through promoting the ROS production.  

UK PubMed Central (United Kingdom)

Recent studies have demonstrated that the Wnt/?-catenin signaling plays an important role in stem cell aging. However, the mechanisms of cell senescence induced by Wnt/?-catenin signaling are still poorly understood. Our preliminary study has indicated that activated Wnt/?-catenin signaling can induce MSC aging. In this study, we reported that the Wnt/?-catenin signaling was a potent activator of reactive oxygen species (ROS) generation in MSCs. After scavenging ROS with N-acetylcysteine, Wnt/?-catenin signaling-induced MSC aging was significantly attenuated and the DNA damage and the expression of p16(INK4A), p53, and p21 were reduced in MSCs. These results indicated that the Wnt/?-catenin signaling could induce MSC aging through promoting the intracellular production of ROS, and ROS may be the main mediators of MSC aging induced by excessive activation of Wnt/?-catenin signaling.

Zhang DY; Pan Y; Zhang C; Yan BX; Yu SS; Wu DL; Shi MM; Shi K; Cai XX; Zhou SS; Wang JB; Pan JP; Zhang LH

2013-02-01

113

UV-B exposure, ROS, and stress: inseparable companions or loosely linked associates?  

UK PubMed Central (United Kingdom)

Ultraviolet-B (UV-B) radiation has long been perceived as a stressor. However, a conceptual U-turn has taken place, and UV-B damage is now considered rare. We question whether UV-stress and UV-B-induced reactive oxygen species (ROS) are still relevant concepts, and if ROS-mediated signaling contributes to UV-B acclimation. Measurements of antioxidants and of antioxidant genes show that both low and high UV-B doses alter ROS metabolism. Yet, there is no evidence that ROS control gene expression under low UV-B. Instead, expression of antioxidant genes is linked to the UV RESISTANCE LOCUS 8 pathway. We hypothesize that low UV-B doses cause 'eustress' (good stress) and that stimuli-specific signaling pathways pre-dispose plants to a state of low alert that includes activation of antioxidant defenses.

Hideg E; Jansen MA; Strid A

2013-02-01

114

Regulation of autophagy by reactive oxygen species (ROS): implications for cancer progression and treatment.  

UK PubMed Central (United Kingdom)

Reactive oxygen species (ROS) have been identified as signaling molecules in various pathways regulating both cell survival and cell death. Autophagy, a self-digestion process that degrades intracellular structures in response to stress, such as nutrient starvation, is also involved in both cell survival and cell death. Alterations in both ROS and autophagy regulation contribute to cancer initiation and progression, and both are targets for developing therapies to induce cell death selectively in cancer cells. Many stimuli that induce ROS generation also induce autophagy, including nutrient starvation, mitochondrial toxins, hypoxia, and oxidative stress. Some of these stimuli are under clinical investigation as cancer treatments, such as 2-methoxyestrodial and arsenic trioxide. Recently, it was demonstrated that ROS can induce autophagy through several distinct mechanisms involving Atg4, catalase, and the mitochondrial electron transport chain (mETC). This leads to both cell-survival and cell-death responses and could be selective toward cancer cells. In this review, we give an overview of the roles ROS and autophagy play in cell survival and cell death, and their importance to cancer. Furthermore, we describe how autophagy is mediated by ROS and the implications of this regulation to cancer treatments.

Azad MB; Chen Y; Gibson SB

2009-04-01

115

Regulation of autophagy by reactive oxygen species (ROS): implications for cancer progression and treatment.  

Science.gov (United States)

Reactive oxygen species (ROS) have been identified as signaling molecules in various pathways regulating both cell survival and cell death. Autophagy, a self-digestion process that degrades intracellular structures in response to stress, such as nutrient starvation, is also involved in both cell survival and cell death. Alterations in both ROS and autophagy regulation contribute to cancer initiation and progression, and both are targets for developing therapies to induce cell death selectively in cancer cells. Many stimuli that induce ROS generation also induce autophagy, including nutrient starvation, mitochondrial toxins, hypoxia, and oxidative stress. Some of these stimuli are under clinical investigation as cancer treatments, such as 2-methoxyestrodial and arsenic trioxide. Recently, it was demonstrated that ROS can induce autophagy through several distinct mechanisms involving Atg4, catalase, and the mitochondrial electron transport chain (mETC). This leads to both cell-survival and cell-death responses and could be selective toward cancer cells. In this review, we give an overview of the roles ROS and autophagy play in cell survival and cell death, and their importance to cancer. Furthermore, we describe how autophagy is mediated by ROS and the implications of this regulation to cancer treatments. PMID:18828708

Azad, Meghan B; Chen, Yongqiang; Gibson, Spencer B

2009-04-01

116

SIRT3 controls cancer metabolic reprogramming by regulating ROS and HIF.  

UK PubMed Central (United Kingdom)

In this issue of Cancer Cell, Finley and coworkers report that the genetic loss of the deacetylase SIRT3 leads to metabolic reprogramming toward glycolysis. This shift is mediated by an increase in cellular reactive oxygen species (ROS) generation that amplifies HIF-? stabilization and HIF-dependent gene expression, thereby driving the tumor phenotype.

Schumacker PT

2011-03-01

117

Mitochondrial ROS fire up T cell activation.  

UK PubMed Central (United Kingdom)

Metabolic reprogramming has emerged as an important feature of immune cell activation. Two new studies, including Sena et al. (2013) in this issue of Immunity, identify mitochondrial reactive oxygen species (ROS) arising from metabolic reprogramming as signaling molecules in T cell activation.

Murphy MP; Siegel RM

2013-02-01

118

Acute changes in temperature or oxygen availability induce ROS fluctuations in Daphnia magna linked with fluctuations of reduced and oxidized glutathione, catalase activity and gene (haemoglobin) expression.  

UK PubMed Central (United Kingdom)

BACKGROUND INFORMATION: ROS (reactive oxygen species) as well as components of the antioxidant redox systems may act as signals. To link acute environmental change with gene expression, changes in ROS and GSH/GSSG (reduced/oxidized glutathione) level were measured upon acute changes in temperature or oxygen availability in the aquatic key species Daphnia magna together with HIF-1 (hypoxia-inducible factor 1)-mediated Hb (haemoglobin) expression. RESULTS: Acute exposures to 30°C or hypoxia, which induced tissue hypoxia (and possibly elevated mitochondrial ROS production), caused resembling fluctuations of ROS and GSH levels, with frequency and number of peaks increasing and their delay decreasing with the magnitude of environmental change (size of tissue hypoxia). Acute hyperoxia induced an initial decrease in ROS level. Evidence is also provided for the promoting effects of ROS on catalase activity. A signalling function of the ROS fluctuations upon acute changes in temperature was found in the case of Hb, the expression of which is known to respond to temperature changes, by detecting corresponding time courses of both transcription and protein formation. CONCLUSION: ROS-dependent signalling was affected by changes in temperature or oxygen availability. Feedback interactions between ROS and the glutathione redox system, possibly driven by elevated mitochondrial ROS production, likely contributed to the appearance of the ROS and GSH fluctuations upon acute environmental change. Fluctuating ROS levels, which reflect for the magnitude of environmental change, could be a way to transfer information on ROS production to subsequent processes (gene expression) while avoiding too-high and damaging ROS levels.

Becker D; Brinkmann BF; Zeis B; Paul RJ

2011-08-01

119

Sense and sensitivity: FOXO and ROS in cancer development and treatment.  

Science.gov (United States)

Forkhead box O (FOXO) transcription factors are at the center of an emerging paradigm that links longevity, cell fate, and tumor development. Key to these processes is the ability of FOXO to regulate, and be regulated by, oxidative stress. Perturbation of the mechanisms that tightly couple reactive oxygen species (ROS) production, oxidative stress signaling, and FOXO activity to the subsequent cellular response is a pivotal step in cancer development and progression. Consequently, the ROS-FOXO pathway is a major therapeutic target in cancer, not only as it mediates the cellular response to chemotherapy, but also because it underpins drug resistance. As the intimate and reciprocal relation between FOXO and ROS is being unravelled, new opportunities arise to develop more-effective cancer treatments that circumvent resistance to the conventional cytotoxic drugs. PMID:20649462

Myatt, Stephen S; Brosens, Jan J; Lam, Eric W-F

2010-10-20

120

Sense and sensitivity: FOXO and ROS in cancer development and treatment.  

UK PubMed Central (United Kingdom)

Forkhead box O (FOXO) transcription factors are at the center of an emerging paradigm that links longevity, cell fate, and tumor development. Key to these processes is the ability of FOXO to regulate, and be regulated by, oxidative stress. Perturbation of the mechanisms that tightly couple reactive oxygen species (ROS) production, oxidative stress signaling, and FOXO activity to the subsequent cellular response is a pivotal step in cancer development and progression. Consequently, the ROS-FOXO pathway is a major therapeutic target in cancer, not only as it mediates the cellular response to chemotherapy, but also because it underpins drug resistance. As the intimate and reciprocal relation between FOXO and ROS is being unravelled, new opportunities arise to develop more-effective cancer treatments that circumvent resistance to the conventional cytotoxic drugs.

Myatt SS; Brosens JJ; Lam EW

2011-02-01

 
 
 
 
121

Mitochondrial Dysfunction Indirectly Elevates ROS Production by the Endoplasmic Reticulum.  

UK PubMed Central (United Kingdom)

Mitochondrial dysfunction is often associated with increased reactive oxygen species (ROS) production by the organelle itself. Leadsham et al. (2013) now show that the link between mitochondrial damage and ROS is more complicated, at least in yeast, where signals from damaged mitochondria increase ROS production from the endoplasmic reticulum surface.

Murphy MP

2013-08-01

122

p38 MAPK: A DUAL ROLE IN HEPATOCYTE PROLIFERATION THROUGH ROS.  

UK PubMed Central (United Kingdom)

p38 MAPKs are important mediators of signal transduction that respond to a wide range of extracellular stressors such as UV radiation, osmotic shock, hypoxia, pro-inflammatory cytokines and oxidative stress. The most abundant family member is p38?, which helps to couple cell proliferation and growth in response to certain damaging stimuli. In fact, increased proliferation and impaired differentiation are hallmarks of p38?-deficient cells. It has been reported that ROS play a critical role in cytokine-induced p38? activation. Under physiological conditions, p38? can function as a mediator of ROS signaling and either activate or suppress cell cycle progression depending on the activation stimulus. The interplay between cell proliferation, p38 MAPK activation and ROS production plays an important role in hepatocytes. In fact, low levels of ROS seem to be needed to activate several signaling pathways in response to hepatectomy and to orchestrate liver regeneration. p38 MAPK works as a sensor of oxidative stress and cells that have developed mechanisms to uncople p38 MAPK activation from oxidative stress are more likely to become tumorogenic. So far, p38? influences the redox balance, determining cell survival, terminal differentiation, proliferation and senescence. Further studies would be necessary in order to clarify the precise role of p38 MAPK signaling as a redox therapeutical target.

Tormos AM; Taléns-Visconti R; Nebreda AR; Sastre J

2013-08-01

123

Multiple protective functions of catalase against intercellular apoptosis-inducing ROS signaling of human tumor cells.  

UK PubMed Central (United Kingdom)

Tumor cells are protected against intercellular reactive oxygen species (ROS)-mediated apoptosis signaling mediated by the HOCl and/or the nitric oxide (NO)/peroxynitrite signaling pathway. We have recently shown that tumor cell resistance against HOCl signaling can be abrogated through inhibition of catalase. The protection of tumor cells against the NO/peroxynitrite signaling pathway has remained enigmatic so far. Here, we show that suboptimal inhibition of catalase by 3-aminotriazole or a monoclonal antibody against catalase, as well as partial knockdown of catalase by specific siRNA allows selective reactivation of the NO/peroxynitrite pathway in MKN 45 gastric carcinoma cells, followed by the HOCl pathway at higher inhibitor or siRNA concentrations. In SKN-MC Ewing sarcoma cells, catalase inhibition causes apoptosis induction solely based on the NO/peroxynitrite pathway. Protection against NO/peroxynitrite signaling is shown to be due to the potential of catalase to decompose peroxynitrite. The direct interaction of catalase with peroxynitrite is verified through the detection of compound I (CAT Fe(IV)=O(+)*) after the interaction of peroxynitrite with catalase. In a complementary experiment, addition of catalase protects sensitive transformed cells against ROS-mediated apoptosis induction. Thus, the expression of membrane-associated catalase is sufficient to protect tumor cells against multiple intercellular ROS-mediated signaling pathways.

Heinzelmann S; Bauer G

2010-06-01

124

ROS regulation of microdomain Ca(2+) signalling at the dyads.  

UK PubMed Central (United Kingdom)

Reactive oxygen species (ROS) are emerging as centre-stage players in cardiac functional regulation. ROS and Ca(2+) signals converge at dyads, the structural and functional units of cardiac excitation-contraction coupling. These two prominent signalling systems are intertwined with ROS modulation of the entire Ca(2+)-signalling network, and vice versa. While constitutively generated homoeostatic ROS are important in setting the redox potential of the intracellular milieu, dynamic signalling ROS shape microdomain and global Ca(2+) signals on both the beat-to-beat and greater time scales. However, ROS effects are complex and subtle, characterized by multiphasic and bidirectional Ca(2+) responses; and sustained oxidative stress may lead to compromised contractility and arrhythmogenicity. These new understandings should be leveraged to harness ROS for their beneficial roles while avoiding deleterious effects in the heart.

Zhang H; Gomez AM; Wang X; Yan Y; Zheng M; Cheng H

2013-05-01

125

Microcystin-LR-Caused ROS generation involved in p38 activation and tau hyperphosphorylation in neuroendocrine (PC12) cells.  

UK PubMed Central (United Kingdom)

Microcystin-LR (MC-LR), a potent specific hepatotoxin produced by cyanobacteria, has recently been reported to show neurotoxicity. Our previous study demonstrated that MC-LR caused the reorganization of cytoskeleton architectures and hyperphosphorylation of the cytoskeletal-associated proteins tau and HSP27 in neuroendocrine PC12 cell line by direct PP2A inhibition and indirect p38 mitogen-activated protein kinase (MAPK) activation. It has been shown that oxidative stress is extensively associated with MC-LR toxicity, mainly resulting from an excessive production of reactive oxygen species (ROS). However, the mechanisms by which ROS mediates the cytotoxic action of MC-LR are unclear. In the present study, we investigated whether ROS might play a critical role in MC-LR-induced hyperphosphorylation of microtubule-associated protein tau and the activation of the MAPKs in PC12 cell line. The results showed that MC-LR had time- and concentration-dependent effects on ROS generation, p38-MAPK activation and tau phosphorylation. The time-course studies indicated similar biphasic changes in ROS generation and tau hyperphosphorylation, which started to increase within 1 h and reached the maximum level at 3 h followed by a decrease after prolonged treatment. Furthermore, pretreatment with the antioxidants, N-acetylcysteine and vitamin C, significantly decreased MC-LR-induced ROS generation and effectively attenuated p38-MAPK activation as well as tau hyperphosphorylation. Taken together, these findings suggest that ROS generation triggered by MC-LR is a key intracellular event that contributes to an induction of p38-MAPK activation and tau phosphorylation, and that blockade of this ROS-mediated redox-sensitive signal cascades may attenuate the toxic effects of MC-LR. © 2013 Wiley Periodicals, Inc. Environ Toxicol, 2013.

Meng G; Liu J; Lin S; Guo Z; Xu L

2013-10-01

126

Dexamethasone inhibits the Nox-dependent ROS production via suppression of MKP-1-dependent MAPK pathways in activated microglia  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Nox-2 (also known as gp91phox), a subunit component of NADPH oxidases, generates reactive oxygen species (ROS). Nox-dependent ROS generation and nitric oxide (NO) release by microglia have been implicated in a variety of diseases in the central nervous system. Dexamethasone (Dex) has been shown to suppress the ROS production, NO release and inflammatory reaction of activated microglial cells. However, the underlying mechanisms remain unclear. Results The present study showed that the increased ROS production and NO release in activated BV-2 microglial cells by LPS were associated with increased expression of Nox-2 and iNOS. Dex suppressed the upregulation of Nox-2 and iNOS, as well as the subsequent ROS production and NO synthesis in activated BV-2 cells. This inhibition caused by Dex appeared to be mediated by upregulation of MAPK phosphatase-1 (MKP-1), which antagonizes the activity of mitogen-activated protein kinases (MAPKs). Dex induced-suppression of Nox-2 and -upregulation of MKP-1 was also evident in the activated microglia from corpus callosum of postnatal rat brains. The overexpression of MKP-1 or inhibition of MAPKs (by specific inhibitors of JNK and p38 MAPKs), were found to downregulate the expression of Nox-2 and iNOS and thereby inhibit the synthesis of ROS and NO in activated BV-2 cells. Moreover, Dex was unable to suppress the LPS-induced synthesis of ROS and NO in BV-2 cells transfected with MKP-1 siRNA. On the other hand, knockdown of Nox-2 in BV-2 cells suppressed the LPS-induced ROS production and NO release. Conclusion In conclusion, it is suggested that downregulation of Nox-2 and overexpression of MKP-1 that regulate ROS and NO may form the potential therapeutic strategy for the treatment of neuroinflammation in neurodegenerative diseases.

Huo Yingqian; Rangarajan Parakalan; Ling Eng-Ang; Dheen S Thameem

2011-01-01

127

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

UK PubMed Central (United Kingdom)

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 2O 2) and superoxide (O 2 (-) ) 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 2O 2-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.

Dr K; Chandrika N; Tsai YH; Schmidt W

2013-03-01

128

Involvement of ROS in chlorogenic acid-induced apoptosis of Bcr-Abl+ CML cells.  

UK PubMed Central (United Kingdom)

Chlorogenic acid (Chl) has been reported to possess a wide range of biological and pharmacological properties including induction of apoptosis of Bcr-Abl(+) chronic myeloid leukemia (CML) cell lines and clinical leukemia samples via inhibition of Bcr-Abl phosphorylation. Here we studied the mechanisms of action of Chl in greater detail. Chl treatment induced an early accumulation of intracellular reactive oxygen species (ROS) in Bcr-Abl(+) cells leading to downregulation of Bcr-Abl phosphorylation and apoptosis. Chl treatment upregulated death receptor DR5 and induced loss of mitochondrial membrane potential accompanied by release of cytochrome c from the mitochondria to the cytosol. Pharmacological inhibition of caspase-8 partially inhibited apoptosis, whereas caspase-9 and pan-caspase inhibitor almost completely blocked the killing. Knocking down DR5 using siRNA completely attenuated Chl-induced caspase-8 cleavage but partially inhibited apoptosis. Antioxidant NAC attenuated Chl-induced oxidative stress-mediated inhibition of Bcr-Abl phosphorylation, DR5 upregulation, caspase activation and CML cell death. Our data suggested the involvement of parallel death pathways that converged in mitochondria. The role of ROS in Chl-induced death was confirmed with primary leukemia cells from CML patients in vitro as well as in vivo in nude mice bearing K562 xenografts. Collectively, our results establish the role of ROS for Chl-mediated preferential killing of Bcr-Abl(+) cells.

Rakshit S; Mandal L; Pal BC; Bagchi J; Biswas N; Chaudhuri J; Chowdhury AA; Manna A; Chaudhuri U; Konar A; Mukherjee T; Jaisankar P; Bandyopadhyay S

2010-12-01

129

Involvement of ROS in chlorogenic acid-induced apoptosis of Bcr-Abl+ CML cells.  

Science.gov (United States)

Chlorogenic acid (Chl) has been reported to possess a wide range of biological and pharmacological properties including induction of apoptosis of Bcr-Abl(+) chronic myeloid leukemia (CML) cell lines and clinical leukemia samples via inhibition of Bcr-Abl phosphorylation. Here we studied the mechanisms of action of Chl in greater detail. Chl treatment induced an early accumulation of intracellular reactive oxygen species (ROS) in Bcr-Abl(+) cells leading to downregulation of Bcr-Abl phosphorylation and apoptosis. Chl treatment upregulated death receptor DR5 and induced loss of mitochondrial membrane potential accompanied by release of cytochrome c from the mitochondria to the cytosol. Pharmacological inhibition of caspase-8 partially inhibited apoptosis, whereas caspase-9 and pan-caspase inhibitor almost completely blocked the killing. Knocking down DR5 using siRNA completely attenuated Chl-induced caspase-8 cleavage but partially inhibited apoptosis. Antioxidant NAC attenuated Chl-induced oxidative stress-mediated inhibition of Bcr-Abl phosphorylation, DR5 upregulation, caspase activation and CML cell death. Our data suggested the involvement of parallel death pathways that converged in mitochondria. The role of ROS in Chl-induced death was confirmed with primary leukemia cells from CML patients in vitro as well as in vivo in nude mice bearing K562 xenografts. Collectively, our results establish the role of ROS for Chl-mediated preferential killing of Bcr-Abl(+) cells. PMID:20832390

Rakshit, Srabanti; Mandal, Labanya; Pal, Bikas Chandra; Bagchi, Jayashree; Biswas, Nabendu; Chaudhuri, Jaydeep; Chowdhury, Avik Acharya; Manna, Anirban; Chaudhuri, Utpal; Konar, Aditya; Mukherjee, Tulika; Jaisankar, Parasuraman; Bandyopadhyay, Santu

2010-09-09

130

Biochemical studies on hemoglobin modified with reactive oxygen species (ROS).  

Science.gov (United States)

Hemoglobin is the iron-containing oxygen transporting metalloprotein in the red cells of blood in mammals and other animals. Hemoprotein-mediated oxidative stress is thought to play a major role in pathophysiology of cerebral hemorrhage, blast pressure injury, crush injury, myocardial ischemia reperfusion injury. Hemoglobin undergoes oxidation-reduction reactions that lead to both generation and consumption of highly reactive oxygen and nitrogen species. In the present study, hemoglobin molecule was treated with hydrogen peroxide and the modification so incurred was analyzed by UV spectra, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and detection of carbonyl content. Our observations suggest that carbonyl content increases with increase in concentration of hydrogen peroxide. Production of hydroxyl radical was assessed by using benzoate degradation analysis. Our results was in tandem with the fact that hemoglobin on treatment with hydrogen peroxide rapidly generates free-radical species that can degrade benzoate to thiobarbituric acid reactive material which on reacting with thiobarbituric acid gives color. The increase in absorbance of ROS-modified hemoglobin at 532 nm shows the increase in benzoate degradation, which is a parameter of hydroxyl radical formation with increase in concentration of hydrogen peroxide. Modified hemoglobin was treated with catalase, mannitol, thiourea, glutathion, sodium benzoate and their effect were detected by spectroscopy and SDS-PAGE (12%). Substantial scavenging effect of aforementioned antioxidants reiterates the formation of hydroxyl radical. Catalase shows the maximum scavenging effect followed by thiourea and mannitol. PMID:21416337

Khaket, Tejinder Pal; Ahmad, Rizwan

2011-03-18

131

Biochemical studies on hemoglobin modified with reactive oxygen species (ROS).  

UK PubMed Central (United Kingdom)

Hemoglobin is the iron-containing oxygen transporting metalloprotein in the red cells of blood in mammals and other animals. Hemoprotein-mediated oxidative stress is thought to play a major role in pathophysiology of cerebral hemorrhage, blast pressure injury, crush injury, myocardial ischemia reperfusion injury. Hemoglobin undergoes oxidation-reduction reactions that lead to both generation and consumption of highly reactive oxygen and nitrogen species. In the present study, hemoglobin molecule was treated with hydrogen peroxide and the modification so incurred was analyzed by UV spectra, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and detection of carbonyl content. Our observations suggest that carbonyl content increases with increase in concentration of hydrogen peroxide. Production of hydroxyl radical was assessed by using benzoate degradation analysis. Our results was in tandem with the fact that hemoglobin on treatment with hydrogen peroxide rapidly generates free-radical species that can degrade benzoate to thiobarbituric acid reactive material which on reacting with thiobarbituric acid gives color. The increase in absorbance of ROS-modified hemoglobin at 532 nm shows the increase in benzoate degradation, which is a parameter of hydroxyl radical formation with increase in concentration of hydrogen peroxide. Modified hemoglobin was treated with catalase, mannitol, thiourea, glutathion, sodium benzoate and their effect were detected by spectroscopy and SDS-PAGE (12%). Substantial scavenging effect of aforementioned antioxidants reiterates the formation of hydroxyl radical. Catalase shows the maximum scavenging effect followed by thiourea and mannitol.

Khaket TP; Ahmad R

2011-08-01

132

Mouse model for ROS1-rearranged lung cancer.  

UK PubMed Central (United Kingdom)

Genetic rearrangement of the ROS1 receptor tyrosine kinase was recently identified as a distinct molecular signature for human non-small cell lung cancer (NSCLC). However, direct evidence of lung carcinogenesis induced by ROS1 fusion genes remains to be verified. The present study shows that EZR-ROS1 plays an essential role in the oncogenesis of NSCLC harboring the fusion gene. EZR-ROS1 was identified in four female patients of lung adenocarcinoma. Three of them were never smokers. Interstitial deletion of 6q22-q25 resulted in gene fusion. Expression of the fusion kinase in NIH3T3 cells induced anchorage-independent growth in vitro, and subcutaneous tumors in nude mice. This transforming ability was attributable to its kinase activity. The ALK/MET/ROS1 kinase inhibitor, crizotinib, suppressed fusion-induced anchorage-independent growth of NIH3T3 cells. Most importantly, established transgenic mouse lines specifically expressing EZR-ROS1 in lung alveolar epithelial cells developed multiple adenocarcinoma nodules in both lungs at an early age. These data suggest that the EZR-ROS1 is a pivotal oncogene in human NSCLC, and that this animal model could be valuable for exploring therapeutic agents against ROS1-rearranged lung cancer.

Arai Y; Totoki Y; Takahashi H; Nakamura H; Hama N; Kohno T; Tsuta K; Yoshida A; Asamura H; Mutoh M; Hosoda F; Tsuda H; Shibata T

2013-01-01

133

Mouse Model for ROS1-Rearranged Lung Cancer  

Science.gov (United States)

Genetic rearrangement of the ROS1 receptor tyrosine kinase was recently identified as a distinct molecular signature for human non-small cell lung cancer (NSCLC). However, direct evidence of lung carcinogenesis induced by ROS1 fusion genes remains to be verified. The present study shows that EZR-ROS1 plays an essential role in the oncogenesis of NSCLC harboring the fusion gene. EZR-ROS1 was identified in four female patients of lung adenocarcinoma. Three of them were never smokers. Interstitial deletion of 6q22–q25 resulted in gene fusion. Expression of the fusion kinase in NIH3T3 cells induced anchorage-independent growth in vitro, and subcutaneous tumors in nude mice. This transforming ability was attributable to its kinase activity. The ALK/MET/ROS1 kinase inhibitor, crizotinib, suppressed fusion-induced anchorage-independent growth of NIH3T3 cells. Most importantly, established transgenic mouse lines specifically expressing EZR-ROS1 in lung alveolar epithelial cells developed multiple adenocarcinoma nodules in both lungs at an early age. These data suggest that the EZR-ROS1 is a pivotal oncogene in human NSCLC, and that this animal model could be valuable for exploring therapeutic agents against ROS1-rearranged lung cancer.

Takahashi, Hiroyuki; Nakamura, Hiromi; Hama, Natsuko; Kohno, Takashi; Tsuta, Koji; Yoshida, Akihiko; Asamura, Hisao; Mutoh, Michihiro; Hosoda, Fumie; Tsuda, Hitoshi; Shibata, Tatsuhiro

2013-01-01

134

How aluminum, an intracellular ROS generator promotes hepatic and neurological diseases: the metabolic tale.  

UK PubMed Central (United Kingdom)

Metal pollutants are a global health risk due to their ability to contribute to a variety of diseases. Aluminum (Al), a ubiquitous environmental contaminant is implicated in anemia, osteomalacia, hepatic disorder, and neurological disorder. In this review, we outline how this intracellular generator of reactive oxygen species (ROS) triggers a metabolic shift towards lipogenesis in astrocytes and hepatocytes. This Al-evoked phenomenon is coupled to diminished mitochondrial activity, anerobiosis, and the channeling of ?-ketoacids towards anti-oxidant defense. The resulting metabolic reconfiguration leads to fat accumulation and a reduction in ATP synthesis, characteristics that are common to numerous medical disorders. Hence, the ability of Al toxicity to create an oxidative environment promotes dysfunctional metabolic processes in astrocytes and hepatocytes. These molecular events triggered by Al-induced ROS production are the potential mediators of brain and liver disorders.

Han S; Lemire J; Appanna VP; Auger C; Castonguay Z; Appanna VD

2013-04-01

135

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

2013-07-16

136

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

UK PubMed Central (United Kingdom)

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.

Lo YL; Wang W

2013-10-01

137

Blood meal-derived heme decreases ROS levels in the midgut of Aedes aegypti and allows proliferation of intestinal microbiota.  

Science.gov (United States)

The presence of bacteria in the midgut of mosquitoes antagonizes infectious agents, such as Dengue and Plasmodium, acting as a negative factor in the vectorial competence of the mosquito. Therefore, knowledge of the molecular mechanisms involved in the control of midgut microbiota could help in the development of new tools to reduce transmission. We hypothesized that toxic reactive oxygen species (ROS) generated by epithelial cells control bacterial growth in the midgut of Aedes aegypti, the vector of Yellow fever and Dengue viruses. We show that ROS are continuously present in the midgut of sugar-fed (SF) mosquitoes and a blood-meal immediately decreased ROS through a mechanism involving heme-mediated activation of PKC. This event occurred in parallel with an expansion of gut bacteria. Treatment of sugar-fed mosquitoes with increased concentrations of heme led to a dose dependent decrease in ROS levels and a consequent increase in midgut endogenous bacteria. In addition, gene silencing of dual oxidase (Duox) reduced ROS levels and also increased gut flora. Using a model of bacterial oral infection in the gut, we show that the absence of ROS resulted in decreased mosquito resistance to infection, increased midgut epithelial damage, transcriptional modulation of immune-related genes and mortality. As heme is a pro-oxidant molecule released in large amounts upon hemoglobin degradation, oxidative killing of bacteria in the gut would represent a burden to the insect, thereby creating an extra oxidative challenge to the mosquito. We propose that a controlled decrease in ROS levels in the midgut of Aedes aegypti is an adaptation to compensate for the ingestion of heme. PMID:21445237

Oliveira, Jose Henrique M; Gonçalves, Renata L S; Lara, Flavio A; Dias, Felipe A; Gandara, Ana Caroline P; Menna-Barreto, Rubem F S; Edwards, Meredith C; Laurindo, Francisco R M; Silva-Neto, Mário A C; Sorgine, Marcos H F; Oliveira, Pedro L

2011-03-17

138

Mitochondrial uncoupling in skeletal muscle by UCP1 augments energy expenditure and glutathione content while mitigating ROS production.  

UK PubMed Central (United Kingdom)

Enhancement of proton leaks in muscle tissue represents a potential target for obesity treatment. In this study, we examined the bioenergetic and physiological implications of increased proton leak in skeletal muscle. To induce muscle-specific increases in proton leak, we used mice that selectively express uncoupling protein-1 (UCP1) in skeletal muscle tissue. UCP1 expression in muscle mitochondria was ?13% of levels in brown adipose tissue (BAT) mitochondria and caused increased GDP-sensitive proton leak. This was associated with an increase in whole body energy expenditure and a decrease in white adipose tissue content. Muscle UCP1 activity had divergent effects on mitochondrial ROS emission and glutathione levels compared with BAT. UCP1 in muscle increased total mitochondrial glutathione levels ?7.6 fold. Intriguingly, unlike in BAT mitochondria, leak through UCP1 in muscle controlled mitochondrial ROS emission. Inhibition of UCP1 with GDP in muscle mitochondria increased ROS emission ?2.8-fold relative to WT muscle mitochondria. GDP had no impact on ROS emission from BAT mitochondria from either genotype. Collectively, these findings indicate that selective induction of UCP1-mediated proton leak in muscle can increase whole body energy expenditure and decrease adiposity. Moreover, ectopic UCP1 expression in skeletal muscle can control mitochondrial ROS emission, while it apparently plays no such role in its endogenous tissue, brown fat.

Adjeitey CN; Mailloux RJ; Dekemp RA; Harper ME

2013-08-01

139

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

140

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

UK PubMed Central (United Kingdom)

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.

Villena J; Henriquez M; Torres V; Moraga F; Díaz-Elizondo J; Arredondo C; Chiong M; Olea-Azar C; Stutzin A; Lavandero S; Quest AF

2008-03-01

 
 
 
 
141

The MPK6-ERF6-ROS-responsive cis-acting Element7/GCC box complex modulates oxidative gene transcription and the oxidative response in Arabidopsis.  

UK PubMed Central (United Kingdom)

Reactive oxygen species (ROS) have been characterized as both important signaling molecules and universal stressors that mediate many developmental and physiological responses. So far, details of the transcriptional mechanism of ROS-responsive genes are largely unknown. In the study reported here, we identified seven potential ROS-responsive cis-acting elements (ROSEs) from the promoters of genes up-regulated by ROS in Arabidopsis (Arabidopsis thaliana). We also found that the APETALA2/ethylene-responsive element binding factor6 (ERF6) could bind specifically to the ROSE7/GCC box. Coexpression of ERF6 enhanced luciferase activity driven by ROSE7. The deficient mutants of ERF6 showed growth retardation and higher sensitivity to photodamage. ERF6 interacted physically with mitogen-activated protein kinase6 (MPK6) and also served as a substrate of MPK6. MPK6-mediated ERF6 phosphorylation at both serine-266 and serine-269 affected the dynamic alternation of the ERF6 protein, which resulted in changes in ROS-responsive gene transcription. These data might provide new insight into the mechanisms that regulate ROS-responsive gene transcription via a complex of MPK6, ERF6, and the ROSE7/GCC box under oxidative stress or a fluctuating light environment.

Wang P; Du Y; Zhao X; Miao Y; Song CP

2013-03-01

142

RET, ROS1 and ALK fusions in lung cancer.  

UK PubMed Central (United Kingdom)

Through an integrated molecular- and histopathology-based screening system, we performed a screening for fusions of anaplastic lymphoma kinase (ALK) and c-ros oncogene 1, receptor tyrosine kinase (ROS1) in 1,529 lung cancers and identified 44 ALK-fusion-positive and 13 ROS1-fusion-positive adenocarcinomas, including for unidentified fusion partners for ROS1. In addition, we discovered previously unidentified kinase fusions that may be promising for molecular-targeted therapy, kinesin family member 5B (KIF5B)-ret proto-oncogene (RET) and coiled-coil domain containing 6 (CCDC6)-RET, in 14 adenocarcinomas. A multivariate analysis of 1,116 adenocarcinomas containing these 71 kinase-fusion-positive adenocarcinomas identified four independent factors that are indicators of poor prognosis: age ? 50 years, male sex, high pathological stage and negative kinase-fusion status.

Takeuchi K; Soda M; Togashi Y; Suzuki R; Sakata S; Hatano S; Asaka R; Hamanaka W; Ninomiya H; Uehara H; Lim Choi Y; Satoh Y; Okumura S; Nakagawa K; Mano H; Ishikawa Y

2012-03-01

143

RET, ROS1 and ALK fusions in lung cancer.  

Science.gov (United States)

Through an integrated molecular- and histopathology-based screening system, we performed a screening for fusions of anaplastic lymphoma kinase (ALK) and c-ros oncogene 1, receptor tyrosine kinase (ROS1) in 1,529 lung cancers and identified 44 ALK-fusion-positive and 13 ROS1-fusion-positive adenocarcinomas, including for unidentified fusion partners for ROS1. In addition, we discovered previously unidentified kinase fusions that may be promising for molecular-targeted therapy, kinesin family member 5B (KIF5B)-ret proto-oncogene (RET) and coiled-coil domain containing 6 (CCDC6)-RET, in 14 adenocarcinomas. A multivariate analysis of 1,116 adenocarcinomas containing these 71 kinase-fusion-positive adenocarcinomas identified four independent factors that are indicators of poor prognosis: age ? 50 years, male sex, high pathological stage and negative kinase-fusion status. PMID:22327623

Takeuchi, Kengo; Soda, Manabu; Togashi, Yuki; Suzuki, Ritsuro; Sakata, Seiji; Hatano, Satoko; Asaka, Reimi; Hamanaka, Wakako; Ninomiya, Hironori; Uehara, Hirofumi; Lim Choi, Young; Satoh, Yukitoshi; Okumura, Sakae; Nakagawa, Ken; Mano, Hiroyuki; Ishikawa, Yuichi

2012-02-12

144

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

145

Molecular Pathways: ROS1 Fusion Proteins in Cancer.  

UK PubMed Central (United Kingdom)

Genetic alterations that lead to constitutive activation of kinases are frequently observed in cancer. In many cases, the growth and survival of tumor cells rely upon an activated kinase such that inhibition of its activity is an effective anticancer therapy. ROS1 is a receptor tyrosine kinase that has recently been shown to undergo genetic rearrangements in a variety of human cancers, including glioblastoma, non-small cell lung cancer (NSCLC), cholangiocarcinoma, ovarian cancer, gastric adenocarcinoma, colorectal cancer, inflammatory myofibroblastic tumor, angiosarcoma, and epithelioid hemangioendothelioma. These rearrangements create fusion proteins in which the kinase domain of ROS1 becomes constitutively active and drives cellular proliferation. Targeting ROS1 fusion proteins with the small-molecule inhibitor crizotinib is showing promise as an effective therapy in patients with NSCLC whose tumors are positive for these genetic abnormalities. This review discusses the recent preclinical and clinical findings on ROS1 gene fusions in cancer. Clin Cancer Res; 19(15); 4040-5. ©2013 AACR.

Davies KD; Doebele RC

2013-08-01

146

Evidence of mitochondrial dysfunction and impaired ROS detoxifying machinery in Fanconi Anemia cells.  

UK PubMed Central (United Kingdom)

Fanconi Anemia (FA) is a rare genetic disorder associated with a bone-marrow failure, cancer predisposition and hypersensitivity to DNA crosslinking agents. Majority of the 15 FA genes and encoded proteins characterized so far are integrated into DNA repair pathways, however, other important functions cannot be excluded. FA cells are sensitive to oxidants, and accumulation of oxidized proteins has been characterized for several FA subgroups. Clinical phenotypes of both FA and other closely related diseases suggest altered functions of mitochondria, organelles responsible for cellular energetic metabolism, and also serving as an important producer and the most susceptible target from reactive oxidative species (ROS). In this study, we have shown that elevated level of mitochondrial ROS in FA cells is in parallel with the decrease of mitochondrial membrane potential, the decrease of ATP production, impaired oxygen uptake and pathological changes in the morphology of mitochondria. This is accompanied by inactivation of enzymes that are essential for the energy production (F1F0ATPase and cytochrome C oxidase) and detoxification of ROS (superoxide dismutase, SOD1). In turn, overexpression of SOD1 could rescue oxygen consumption rate in FA-deficient cells. Importantly, the depletion of mitochondria improved survival rate of mitomycin C treated FA cells suggesting that hypersensitivity of FA cells to chemotherapeutic drugs could be in part due to the mitochondria-mediated oxidative stress. On the basis of our results, we propose that deficiency in FA genes lead to disabling mitochondrial ROS-scavenging machinery further affecting mitochondrial functions and suppressing cell respiration.Oncogene advance online publication, 14 January 2013; doi:10.1038/onc.2012.583.

Kumari U; Ya Jun W; Huat Bay B; Lyakhovich A

2013-01-01

147

ROS production and NF-?B activation triggered by RAC1 facilitate WNT-driven intestinal stem cell proliferation and colorectal cancer initiation.  

UK PubMed Central (United Kingdom)

The Adenomatous Polyposis Coli (APC) gene is mutated in the majority of colorectal cancers (CRCs). Loss of APC leads to constitutively active WNT signaling, hyperproliferation, and tumorigenesis. Identification of pathways that facilitate tumorigenesis after APC loss is important for therapeutic development. Here, we show that RAC1 is a critical mediator of tumorigenesis after APC loss. We find that RAC1 is required for expansion of the LGR5 intestinal stem cell (ISC) signature, progenitor hyperproliferation, and transformation. Mechanistically, RAC1-driven ROS and NF-?B signaling mediate these processes. Together, these data highlight that ROS production and NF-?B activation triggered by RAC1 are critical events in CRC initiation.

Myant KB; Cammareri P; McGhee EJ; Ridgway RA; Huels DJ; Cordero JB; Schwitalla S; Kalna G; Ogg EL; Athineos D; Timpson P; Vidal M; Murray GI; Greten FR; Anderson KI; Sansom OJ

2013-06-01

148

Ras-induced ROS upregulation affecting cell proliferation is connected with cell type-specific alterations of HSF1/SESN3/p21Cip1/WAF1 pathways.  

UK PubMed Central (United Kingdom)

Oncogenes of the RAS family regulate many of the cell's activities, including proliferation, survival and differentiation. Activating mutations in these genes are common events for many types of cancer. One of the contradictory points concerning the biological significance of Ras activation is its dual effect (pro- or anti-proliferative) on cell reproduction. One of mechanisms by which Ras proteins influence cell growth is a regulation of intracellular level of reactive oxygen species (ROS), second messengers affecting variety of cellular processes including cell proliferation. Recently it was shown that repression of SESN1 and SESN3 genes, whose protein products control regeneration of peroxiredoxins, can play a critical role in Ras-induced ROS upregulation. In the present study we have found that Ras-induced repression of SESN3 expression and ROS upregulation is mediated via the modifications of transcriptional activity of HSF1. Interestingly, mutant Ras overexpression altered the activity of HSF1 in opposite directions in different cell contexts, in particular in human normal fibroblasts and HaCaT immortalized keratinocytes, but these opposite changes caused similar repression of SESN3 expression followed by elevation of ROS content and inhibition of cell proliferation in corresponding cell types. The inhibitory effect on cell proliferation was mediated by upregulation of p21(Cip1/WAF1). Thus, HSF1/SESN3/ROS/p21(Cip1/WAF1)-mediated deceleration of cell growth may contribute to cell defense systems protecting the organism from excessive proliferation of cells that overexpress activated Ras oncoproteins.

Zamkova M; Khromova N; Kopnin BP; Kopnin P

2013-03-01

149

Prostaglandin E2 is critical for the development of niacin-deficiency-induced photosensitivity via ROS production  

Science.gov (United States)

Pellagra is a photosensitivity syndrome characterized by three “D's”: diarrhea, dermatitis, and dementia as a result of niacin deficiency. However, the molecular mechanisms of photosensitivity dermatitis, the hallmark abnormality of this syndrome, remain unclear. We prepared niacin deficient mice in order to develop a murine model of pellagra. Niacin deficiency induced photosensitivity and severe diarrhea with weight loss. In addition, niacin deficient mice exhibited elevated expressions of COX-2 and PGE syntheses (Ptges) mRNA. Consistently, photosensitivity was alleviated by a COX inhibitor, deficiency of Ptges, or blockade of EP4 receptor signaling. Moreover, enhanced PGE2 production in niacin deficiency was mediated via ROS production in keratinocytes. In line with the above murine findings, human skin lesions of pellagra patients confirmed the enhanced expression of Ptges. Niacin deficiency-induced photosensitivity was mediated through EP4 signaling in response to increased PGE2 production via induction of ROS formation.

Sugita, Kazunari; Ikenouchi-Sugita, Atsuko; Nakayama, Yasuko; Yoshioka, Haruna; Nomura, Takashi; Sakabe, Jun-ichi; Nakahigashi, Kyoko; Kuroda, Etsushi; Uematsu, Satoshi; Nakamura, Jun; Akira, Shizuo; Nakamura, Motonobu; Narumiya, Shuh; Miyachi, Yoshiki; Tokura, Yoshiki; Kabashima, Kenji

2013-01-01

150

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

2010-02-20

151

Brain Stem NOS and ROS in Neural Mechanisms of Hypertension.  

UK PubMed Central (United Kingdom)

Abstract Significance: There is now compelling evidence to substantiate the notion that by depressing baroreflex regulation of blood pressure and augmenting central sympathetic outflow through their actions on the nucleus tractus solitarii (NTS) and rostral ventrolateral medulla (RVLM), brain stem nitric oxide synthase (NOS) and reactive oxygen species (ROS) are important contributing factors to neural mechanisms of hypertension. This review summarizes our contemporary views on the impact of NOS and ROS in the NTS and RVLM on neurogenic hypertension, and presents potential antihypertensive strategies that target brain stem NOS/ROS signaling. Recent Advances: NO signaling in the brain stem may be pro- or antihypertensive depending on the NOS isoform that generates this gaseous moiety and the site of action. Elevation of the ROS level when its production overbalances its degradation in the NTS and RVLM underlies neurogenic hypertension. Interventional strategies with emphases on alleviating the adverse actions of these molecules on blood pressure regulation have been investigated. Critical Issues: The pathological roles of NOS in the RVLM and NTS in neural mechanisms of hypertension are highly complex. Likewise, multiple signaling pathways underlie the deleterious roles of brain-stem ROS in neurogenic hypertension. There are recent indications that interactions between brain stem ROS and NOS may play a contributory role. Future Directions: Given the complicity of action mechanisms of brain-stem NOS and ROS in neural mechanisms of hypertension, additional studies are needed to identify the most crucial therapeutic target that is applicable not only in animal models but also in patients suffering from neurogenic hypertension. Antioxid. Redox Signal. 00, 000-000.

Chan SH; Chan JY

2013-03-01

152

Mitochondrial proticity and ROS signaling: lessons from the uncoupling proteins.  

UK PubMed Central (United Kingdom)

Fifty years since Peter Mitchell proposed the theory of chemiosmosis, the transformation of cellular redox potential into ATP synthetic capacity is still a widely recognized function of mitochondria. Mitchell used the term 'proticity' to describe the force and flow of the proton circuit across the inner membrane. When the proton gradient is coupled to ATP synthase activity, the conversion of fuel to ATP is efficient. However, uncoupling proteins (UCPs) can cause proton leaks resulting in poor fuel conversion efficiency, and some UCPs might control mitochondrial reactive oxygen species (ROS) production. Once viewed as toxic metabolic waste, ROS are now implicated in cell signaling and regulation. Here, we discuss the role of mitochondrial proticity in the context of ROS production and signaling.

Mailloux RJ; Harper ME

2012-09-01

153

Mitochondrial proticity and ROS signaling: lessons from the uncoupling proteins.  

Science.gov (United States)

Fifty years since Peter Mitchell proposed the theory of chemiosmosis, the transformation of cellular redox potential into ATP synthetic capacity is still a widely recognized function of mitochondria. Mitchell used the term 'proticity' to describe the force and flow of the proton circuit across the inner membrane. When the proton gradient is coupled to ATP synthase activity, the conversion of fuel to ATP is efficient. However, uncoupling proteins (UCPs) can cause proton leaks resulting in poor fuel conversion efficiency, and some UCPs might control mitochondrial reactive oxygen species (ROS) production. Once viewed as toxic metabolic waste, ROS are now implicated in cell signaling and regulation. Here, we discuss the role of mitochondrial proticity in the context of ROS production and signaling. PMID:22591987

Mailloux, Ryan J; Harper, Mary-Ellen

2012-05-15

154

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

Science.gov (United States)

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 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.

De Giusti, V. C.; Caldiz, C. I.; Ennis, I. E.; Perez, N. G.; Cingolani, H. E.; Aiello, E. A.

2013-01-01

155

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(P)H 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.

Kohfuku Kohda; Hitomi Goda; Kei Itoh; Keijiro Samejima; Tomoko Fukuuchi

2013-01-01

156

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

Science.gov (United States)

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 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. PMID:23755021

De Giusti, V C; Caldiz, C I; Ennis, I E; Pérez, N G; Cingolani, H E; Aiello, E A

2013-05-30

157

Monosodium iodoacetate induces apoptosis via the mitochondrial pathway involving ROS production and caspase activation in rat chondrocytes in vitro.  

UK PubMed Central (United Kingdom)

Monosodium iodoacetate (MIA) is an inhibitor of glyceraldehyde-3-phosphate dehydrogenase activity, and causes dose-dependent cartilage degradation resembling the pathological changes of human osteoarthritis (OA). In this study, we assessed the apoptosis induced by MIA and clarified the underlying mechanisms using the primary rat chondrocytes. The apoptosis of primary rat chondrocytes was analyzed by flow cytometry. The levels of mitochondrial membrane potential (??m) were evaluated using fluorescence spectrophotometer. The production of reactive oxygen species (ROS) was determined by fluorescence spectrophotometer. Apoptosis-related protein cytochrome c and procaspase-3 expressions were examined by Western blotting. We found that MIA treatment induces apoptosis in chondrocytes, as confirmed by increases in the percent of apoptotic cells, up-regulation of cytochrome c and caspase-3 protein levels. Treatment with MIA increases ROS production and decreases the levels of ??m. The antioxidant, N-acetylcysteine (NAC), significantly prevented the production of ROS, the reduction of ??m, the release of cytochrome c and the activation of caspase-3. Further, NAC completely protected the cells from MIA-induced apoptosis. Together these observations suggest that the mechanisms of MIA-induced apoptosis are primarily via ROS production and mitochondria-mediated caspase-3 activation in primary rat chondrocytes.

Jiang L; Li L; Geng C; Gong D; Jiang L; Ishikawa N; Kajima K; Zhong L

2013-03-01

158

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.

2010-01-01

159

Down-regulation of Fer induces ROS levels accompanied by ATM and p53 activation in colon carcinoma cells.  

Science.gov (United States)

Fer is an intracellular tyrosine kinase which resides in both the cytoplasm and nucleus of mammalian cells. This kinase was also found in all malignant cell-lines analyzed and was shown to support cell-cycle progression in cancer cells. Herein we show that knock-down of Fer, both, impairs cell-cycle progression and imposes programmed cell death in colon carcinoma (CC) cells. The cell-cycle arrest and apoptotic death invoked by the depletion of Fer were found to depend on the activity of p53. Accordingly, down regulation of Fer led to the activation of the Ataxia Telangiectasia Mutated protein (ATM) and its down-stream effector-p53. Knock-down of Fer also increased the level of Reactive-Oxygen Species (ROS) in CC cells, and subjection of Fer depleted cells to ROS neutralizing scavengers significantly decreased the induced phosphorylation and activation of ATM and p53. Notably, over-expression of Fer opposed the Doxorubicin driven activation of ATM and p53, which can be mediated by ROS. Collectively, our findings imply that Fer sustains low ROS levels in CC cells, thereby restraining the activation of ATM and p53 in these cells. PMID:22434045

Makovski, Adar; Yaffe, Etai; Shpungin, Sally; Nir, Uri

2012-03-11

160

Down-regulation of Fer induces ROS levels accompanied by ATM and p53 activation in colon carcinoma cells.  

UK PubMed Central (United Kingdom)

Fer is an intracellular tyrosine kinase which resides in both the cytoplasm and nucleus of mammalian cells. This kinase was also found in all malignant cell-lines analyzed and was shown to support cell-cycle progression in cancer cells. Herein we show that knock-down of Fer, both, impairs cell-cycle progression and imposes programmed cell death in colon carcinoma (CC) cells. The cell-cycle arrest and apoptotic death invoked by the depletion of Fer were found to depend on the activity of p53. Accordingly, down regulation of Fer led to the activation of the Ataxia Telangiectasia Mutated protein (ATM) and its down-stream effector-p53. Knock-down of Fer also increased the level of Reactive-Oxygen Species (ROS) in CC cells, and subjection of Fer depleted cells to ROS neutralizing scavengers significantly decreased the induced phosphorylation and activation of ATM and p53. Notably, over-expression of Fer opposed the Doxorubicin driven activation of ATM and p53, which can be mediated by ROS. Collectively, our findings imply that Fer sustains low ROS levels in CC cells, thereby restraining the activation of ATM and p53 in these cells.

Makovski A; Yaffe E; Shpungin S; Nir U

2012-07-01

 
 
 
 
161

Surfactin-Induced Apoptosis Through ROS-ERS-Ca(2+)-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

2013-06-01

162

Surfactin-Induced Apoptosis Through ROS-ERS-Ca(2+)-ERK Pathways in HepG2 Cells.  

UK PubMed Central (United Kingdom)

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.

Wang CL; Liu C; Niu LL; Wang LR; Hou LH; Cao XH

2013-06-01

163

Antioxidant N-Acetylcysteine Attenuates Hepatocarcinogenesis by Inhibiting ROS/ER Stress in TLR2 Deficient Mouse  

Science.gov (United States)

Hepatocellular carcinoma (HCC) remains one of the most deadly solid tumor malignancies worldwide. We recently find that the loss of toll-like receptor 2 (TLR2) activities promotes the diethylnitrosamine (DEN) induced hepatocellular carcinogenesis and tumor progression, which associates with an abundant accumulation of reactive oxygen species (ROS) and endoplasmic reticulum (ER) stress. This finding suggests that the ROS/ER stress plays a role in TLR2 modulated carcinogenesis of HCC. To investigate the mechanism of TLR2 activity defending against hepatocarcinogenesis, the TLR2-deficient mice were treated with or without antioxidant N-acetylcysteine (NAC) before DEN administration. We found that pretreatment of these animals with NAC attenuated carcinogenesis and progression of HCC in the TLR2-deficient mice, declined ROS/ER stress, and alleviated the unfold protein response and inflammatory response in TLR2-deficient liver tissue. Moreover, the NAC treatment significantly reduced the enhanced aggregation of p62 and Mallory-Denk bodies in the DEN-induced HCC liver tissue, suggesting that NAC treatment improves the suppressive autophagic flux in the TLR2-deficient liver. These findings indicate that TLR2 activity defends against hepatocarcinogenesis through diminishing the accumulation of ROS and alleviating ER stress and unfold protein response mediated inflammatory response in the liver.

Lin, Heng; Liu, Xiao-bo; Yu, Jiao-jiao; Hua, Fang; Hu, Zhuo-wei

2013-01-01

164

Calcium and ROS rule the waves of signaling.  

UK PubMed Central (United Kingdom)

Calcium signals are central steps of information processing in higher plants. They are involved in almost all physiological and developmental processes. In the past we have witnessed tremendous progress in our understanding how calcium signals are formed and decoded. An elaborate toolkit of calcium regulated kinases conveys the information presented by calcium signals into phosphorylation events. Significant advancements have been achieved in our understanding how calcium and ROS signaling are interconnected. Here we discuss the newest findings about mechanisms that contribute to decoding of calcium signals and present a model how calcium-dependent phosphorylation of ROS generating NADPH oxidases could contribute to long distance signaling in plants.

Steinhorst L; Kudla J

2013-07-01

165

Actin-sequestering protein, thymosin beta-4, induces paclitaxel resistance through ROS/HIF-1alpha stabilization in HeLa human cervical tumor cells.  

UK PubMed Central (United Kingdom)

AIMS: We investigated whether actin-sequestering protein, thymosin beta-4 (TB4)-induced reactive oxygen species (ROS) affect the stabilization of hypoxia-inducible transcription factor (HIF)-1alpha and paclitaxel-resistance induction. MAIN METHODS: HeLa human cervical tumor cells were used. The percentage of cell survival was determined by MTT assay. ROS production, cell cycle and hypodiploid cell formation were assessed by flow cytometry analysis. HIF-1alpha stabilization and molecular changes were analyzed by western blotting or RT-PCR. NF-kappaB activation was assessed by EMSA and western blotting. KEY FINDINGS: TB4 protein (TB4P) significantly increased intracellular ROS level and HIF-1alpha. The increased level of HIF-1alpha by TB4P was reduced by the treatment with N-acetylcysteine (NAC), a well-known ROS scavenger. TB4P-induced ROS production was confirmed by the activation of nuclear factor kappa B. TB4P-induced Erk phosphorylation was attenuated by the treatment with NAC. In addition, tumor cell death was decreased by TB4 gene overexpression and TB4P treatment. NAC treatment attenuated tumor cell density increased by TB4P. Tumor cell death by paclitaxel was also increased by NAC treatment or the transfection with HIF-1alpha-siRNA. Paclitaxel-induced B16F10 mouse melanoma regression was physiologically inhibited in TB4-transgenic mice compared to wildtype mice. SIGNIFICANCE: These findings demonstrate that TB4-induced ROS and ROS-mediated HIF-1alpha stabilization could play a role in tumor cell resistance to anticancer agents like paclitaxel. It suggests that soluble TB4 could be a novel endogenous regulator to control intracellular ROS production in tumor cells.

Oh JM; Moon EY

2010-08-01

166

Ionizing radiation regulates cardiac Ca handling via increased ROS and activated CaMKII.  

Science.gov (United States)

Ionizing radiation (IR) is an integral part of modern multimodal anti-cancer therapies. IR involves the formation of reactive oxygen species (ROS) in targeted tissues. This is associated with subsequent cardiac dysfunction when applied during chest radiotherapy. We hypothesized that IR (i.e., ROS)-dependently impaired cardiac myocytes' Ca handling might contribute to IR-dependent cardiocellular dysfunction. Isolated ventricular mouse myocytes and the mediastinal area of anaesthetized mice (that included the heart) were exposed to graded doses of irradiation (sham 4 and 20 Gy) and investigated acutely (after ~1 h) as well as chronically (after ~1 week). IR induced a dose-dependent effect on myocytes' systolic function with acutely increased, but chronically decreased Ca transient amplitudes, which was associated with an acutely unaltered but chronically decreased sarcoplasmic reticulum (SR) Ca load. Likewise, in vivo echocardiography of anaesthetized mice revealed acutely enhanced left ventricular contractility (strain analysis) that declined after 1 week. Irradiated myocytes showed persistently increased diastolic SR Ca leakage, which was acutely compensated by an increase in SR Ca reuptake. This was reversed in the chronic setting in the face of slowed relaxation kinetics. As underlying cause, acutely increased ROS levels were identified to activate Ca/calmodulin-dependent protein kinase II (CaMKII). Accordingly, CaMKII-, but not PKA-dependent phosphorylation sites of the SR Ca release channels (RyR2, at Ser-2814) and phospholamban (at Thr-17) were found to be hyperphosphorylated following IR. Conversely, ROS-scavenging as well as CaMKII-inhibition significantly attenuated CaMKII-activation, disturbed Ca handling, and subsequent cellular dysfunction upon irradiation. Targeted cardiac irradiation induces a biphasic effect on cardiac myocytes Ca handling that is associated with chronic cardiocellular dysfunction. This appears to be mediated by increased oxidative stress and persistently activated CaMKII. Our findings suggest impaired cardiac myocytes Ca handling as a so far unknown mediator of IR-dependent cardiac damage that might be of relevance for radiation-induced cardiac dysfunction. PMID:24068185

Sag, Can M; Wolff, Hendrik A; Neumann, Kay; Opiela, Marie-Kristin; Zhang, Juqian; Steuer, Felicia; Sowa, Thomas; Gupta, Shamindra; Schirmer, Markus; Hünlich, Mark; Rave-Fränk, Margret; Hess, Clemens F; Anderson, Mark E; Shah, Ajay M; Christiansen, Hans; Maier, Lars S

2013-09-26

167

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

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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 moi...

Kohfuku Kohda; Hitomi Goda; Kei Itoh; Keijiro Samejima; Tomoko Fukuuchi

168

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

169

Estrogen Receptor-? But Not -? or GPER Inhibits High Glucose-Induced Human VSMC Proliferation: Potential Role of ROS and ERK  

Science.gov (United States)

Context: The decreased incidence of cardiovascular disease in premenopausal women has been attributed, at least partially, to protective effects of estrogens. However, premenopausal women with diabetes mellitus are no longer selectively protected. High-glucose (HG) conditions have previously been shown to abolish the antimitogenic effects of 17?-estradiol (E2) in vascular smooth muscle cells (VSMCs). Objective: Because E2 mediates its action via different estrogen receptor (ER) subtypes, we hypothesized that different subtypes may have different, if not opposing, effects on HG-induced VSMC proliferation. Methods and Results: Treatment of human aortic VSMCs isolated from premenopausal women with the selective ER? agonist, 4,4?,4?-(4-propyl-[1H]-pyrazole-1,3,5-triyl)trisphenol, but not with E2, the selective ER? agonist 2,3-bis(4-hydroxyphenyl)-propionitrile, or the selective G protein-coupled ER agonist G-1 completely prevented increased HG-induced VSMC proliferation. Under these conditions, ER? activation selectively prevented increased hydrogen peroxide (H2O2) and total intracellular reactive oxygen species (ROS) production, caused up-regulation of manganese superoxide dismutase protein and activity, and inhibited prolonged ERK phosphorylation. The latter was mediated by ROS, and ROS inhibition reversed HG-induced ERK-dependent VSMC proliferation. The selective coactivation of ER? reversed the antimitogenic and antioxidative effects of ER? as well as the up-regulation of manganese superoxide dismutase protein expression. Conclusion: Selective activation of ER? is required for reducing oxidative stress and the consequent hyperproliferation of VSMCs under HG. Our results may further suggest that ER? activation inhibits HG-induced proliferation by down-regulating ROS-mediated ERK activation and may explain why antimitogenic effects of E2 are abolished under HG. Pharmacological activation of ER? may thus have therapeutic potential for treating cardiovascular dysregulation associated with diabetes.

Ortmann, Jana; Veit, Martha; Zingg, Sandra; Di Santo, Stefano; Traupe, Tobias; Yang, Zijiang; Volzmann, Jan; Dubey, Raghvendra K.; Christen, Stephan; Baumgartner, Iris

2011-01-01

170

Mitochondrial ROS and radiation induced transformation in mouse embryonic fibroblasts.  

Science.gov (United States)

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 equitoxic doses of IR, and assayed for transformation frequency, cellular redox environment, DNA damage, and cell cycle checkpoint activation. Transformation frequency increased ( approximately 5-fold) in SOD2 (-/-) compared to SOD2 (+/+) MEFs. Cellular redox environment (GSH, GSSG, DHE and DCFH-oxidation) did not show any significant change within 24 h post-IR. However, a significant increase in cellular ROS levels was observed at 72 h post-IR in SOD2 (-/-) compared to SOD2 (+/+) MEFs, which was consistent with an increase in GSSG in SOD2 (-/-) MEFs. Late ROS accumulation was associated with an increase in micronuclei frequency in SOD2 (-/-) MEFs. Exit from G(2) was accelerated in irradiated SOD2 (+/-) and SOD2 (-/-) compared to SOD2 (+/+) MEFs. These results support the hypothesis that SOD2 activity and mitochondria generated ROS regulate IR induced transformation in mouse embryonic fibroblasts. PMID:19738419

Du, Changbin; Gao, Zhen; Venkatesha, Venkatasubbaiah A; Kalen, Amanda L; Chaudhuri, Leena; Spitz, Douglas R; Cullen, Joseph J; Oberley, Larry W; Goswami, Prabhat C

2009-10-29

171

Mitochondrial ROS and radiation induced transformation in mouse embryonic fibroblasts.  

UK PubMed Central (United Kingdom)

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 equitoxic doses of IR, and assayed for transformation frequency, cellular redox environment, DNA damage, and cell cycle checkpoint activation. Transformation frequency increased ( approximately 5-fold) in SOD2 (-/-) compared to SOD2 (+/+) MEFs. Cellular redox environment (GSH, GSSG, DHE and DCFH-oxidation) did not show any significant change within 24 h post-IR. However, a significant increase in cellular ROS levels was observed at 72 h post-IR in SOD2 (-/-) compared to SOD2 (+/+) MEFs, which was consistent with an increase in GSSG in SOD2 (-/-) MEFs. Late ROS accumulation was associated with an increase in micronuclei frequency in SOD2 (-/-) MEFs. Exit from G(2) was accelerated in irradiated SOD2 (+/-) and SOD2 (-/-) compared to SOD2 (+/+) MEFs. These results support the hypothesis that SOD2 activity and mitochondria generated ROS regulate IR induced transformation in mouse embryonic fibroblasts.

Du C; Gao Z; Venkatesha VA; Kalen AL; Chaudhuri L; Spitz DR; Cullen JJ; Oberley LW; Goswami PC

2009-10-01

172

Kuula : Sigur Ros rokiklubis. Kammemuusikat Tallinnas. Loomade reekviem  

Index Scriptorium Estoniae

23. aug. esineb Tallinna rokiklubis Rock Café islandi bänd Sigur Ros. Pille Lille muusikute toetusfondi korraldatavast Tallinna Kammermuusika festivalist 17.-23. aug. Tallinna Rootsi Mihkli kirikus, Raekojas ja Jaani kirkus (vt. www.plmf.ee). Kontserdist Nargen Festivali raames 30. ja 31. aug. Tallinna loomaaias

2008-01-01

173

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

Science.gov (United States)

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

2013-03-14

174

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

UK PubMed Central (United Kingdom)

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.

Runkel ED; Liu S; Baumeister R; Schulze E

2013-01-01

175

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.

Dorrah Deeb; Xiaohua Gao; Yongbo Liu; Nadimpalli R. S. Varma; Ali S. Arbab; Subhash C. Gautam

2013-01-01

176

Inhibition of telomerase activity by oleanane triterpenoid CDDO-Me in pancreatic cancer cells is ROS-dependent.  

UK PubMed Central (United Kingdom)

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.

Deeb D; Gao X; Liu Y; Varma NR; Arbab AS; Gautam SC

2013-01-01

177

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

Science.gov (United States)

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

178

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, enfàtic, 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

179

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

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Full Text Available 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 cancer cells highly susceptible to quercetin, one of the main dietary flavonoids. Quercetin depletes intracellular glutathione and increases intracellular ROS to a level that can cause cell death.

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

2010-01-01

180

Neurotoxic effects of bisphenol AF on calcium-induced ROS and MAPKs.  

UK PubMed Central (United Kingdom)

Bisphenol AF (BPAF), a newly introduced chemical structurally related to bisphenol A, is used extensively in fluoroelastomers and polyesters, and has been known to induce estrogen-dependent responses. However, the toxicity of BPAF is largely unknown except for its endocrine-related effects. In this study, we investigated the neurotoxicity of BPAF and underlying mechanisms of action using hippocampal cell line (HT-22) and mouse primary neuronal cells. We found that BPAF induced apoptosis in both HT-22 and primary neuronal cells. In order to clarify the underlying mechanisms of BPAF-induced apoptosis, various signaling molecules were evaluated. BPAF increased the level of intracellular calcium, followed by the generation of reactive oxygen species (ROS). BPAF upregulated the phosphorylation of mitogen-activated protein kinase: extracellular signal-regulated kinase, p38 and c-Jun N-terminal kinase (JNK), and nuclear translocation of nuclear factor-?B. Using specific inhibitors, we confirmed that calcium, ROS, p38, and JNK mediated the BPAF-induced apoptosis. In addition, BPAF inhibited microglial activation in a microglia/neuroblastoma coculture model by the reduction of nitric oxide production. We found that BPAF interrupted the normal physiologic functions of microglia at non-toxic levels. Taken together, our results suggest that BPAF, the substitute of BPA, also have neurotoxic properties.

Lee S; Kim YK; Shin TY; Kim SH

2013-04-01

 
 
 
 
181

ROS-induced autophagy in cancer cells assists in evasion from determinants of immunogenic cell death.  

UK PubMed Central (United Kingdom)

Calreticulin surface exposure (ecto-CALR), ATP secretion, maturation of dendritic cells (DCs) and stimulation of T cells are prerequisites for anticancer therapy-induced immunogenic cell death (ICD). Recent evidence suggests that chemotherapy-induced autophagy may positively regulate ICD by favoring ATP secretion. We have recently shown that reactive oxygen species (ROS)-based endoplasmic reticulum (ER) stress triggered by hypericin-mediated photodynamic therapy (Hyp-PDT) induces bona fide ICD. However, whether Hyp-PDT-induced autophagy regulates ICD was not explored. Here we showed that, in contrast to expectations, reducing autophagy (by ATG5 knockdown) in cancer cells did not alter ATP secretion after Hyp-PDT. Autophagy-attenuated cancer cells displayed enhanced ecto-CALR induction following Hyp-PDT, which strongly correlated with their inability to clear oxidatively damaged proteins. Furthermore, autophagy-attenuation in Hyp-PDT-treated cancer cells increased their ability to induce DC maturation, IL6 production and proliferation of CD4 (+) or CD8 (+) T cells, which was accompanied by IFNG production. Thus, our study unravels a role for ROS-induced autophagy in weakening functional interaction between dying cancer cells and the immune system thereby helping in evasion from ICD pre-requisites or determinants.

Garg AD; Dudek AM; Ferreira GB; Verfaillie T; Vandenabeele P; Krysko DV; Mathieu C; Agostinis P

2013-06-01

182

Modulation of intercellular ROS signaling of human tumor cells.  

UK PubMed Central (United Kingdom)

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.

Bechtel W; Bauer G

2009-11-01

183

Zeolites are effective ROS-scavengers in vitro.  

UK PubMed Central (United Kingdom)

We report on the use of zeolites to limit the effects of reactive oxygen species (ROS) on human albumin under in vitro conditions. Zeolites of different structure type, channel size, channel polarity, and charge-compensating cation were screened for the elimination of ROS, notably HO(·), resulting from the Fenton reaction. A test based on ischemia-modified albumin (IMA) was used as a marker to monitor the activity of HO(·) after co-exposure of human serum to these zeolites. Two commercial zeolites, faujasite (FAU 13×, channel opening 0.74×0.74 nm with Na(+) as charge-compensating cation) and ferrierite (FER, channel opening 0.54×0.42 nm with H(+) as charge-compensating cation), were found to reduce IMA formation by more than 65% due to removal of HO(·) relative to reference values. It was established that partial ion exchange of the zeolites' respective charge-compensating cation vs. Fe(3+) implicated in the Fenton reaction plays a major role in HO(·) deactivation process. Moreover, our results show that no saturation of the respective zeolite active sites occurred. This is possible only when ROS are actively converted to water molecules within the zeolite void system, which generates H(+) ion transport. Because zeolites cannot be administered in blood, their use in medicine should be limited to extra corporeal circuits. Zeolites could be of use during cardiopulmonary bypass or hemodialysis procedures.

Pellegrino P; Mallet B; Delliaux S; Jammes Y; Guieu R; Schäf O

2011-07-01

184

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

2013-01-01

185

Heme oxygenase-1 induction by the ROS-JNK pathway plays a role in aluminum-induced anemia.  

UK PubMed Central (United Kingdom)

Aluminum (Al) overload is correlated with hypochromic anemia. It is possible that Al impedes heme biosynthesis and degradation by affecting the activity of biosynthetic enzymes. However, the molecular mechanisms by which Al affects these enzymes are unknown. Here, we show that long-term exposure of Sprague-Dawley rats to Al decreased hemoglobin concentration and the hematocrit level. In addition, the activity of aminolevulinic acid dehydratase (ALA-D) in rat liver was reduced, but heme oxygenase (HO) activity was enhanced, suggesting an impairment of heme homeostasis. The increase in HO activity was due to up-regulation of mRNA and protein of an inducible HO isozyme, HO-1. Furthermore, we found that reactive oxygen species (ROS)-mediated activation of c-Jun N-terminal kinase (JNK) was critical for HO-1 induction by Al, because ROS scavengers and JNK inhibitors abrogated enhancement of HO-1 by Al in rat hepatocytes. Thus, Al enhances HO-1 expression through the ROS-JNK pathway, which may enhance HO activity and accelerate degradation of heme, leading to hypochromic anemia.

Lin CY; Hsiao WC; Huang CJ; Kao CF; Hsu GS

2013-07-01

186

The MPK6-ERF6-ROS-Responsive cis-Acting Element7/GCC Box Complex Modulates Oxidative Gene Transcription and the Oxidative Response in Arabidopsis1[W][OA  

Science.gov (United States)

Reactive oxygen species (ROS) have been characterized as both important signaling molecules and universal stressors that mediate many developmental and physiological responses. So far, details of the transcriptional mechanism of ROS-responsive genes are largely unknown. In the study reported here, we identified seven potential ROS-responsive cis-acting elements (ROSEs) from the promoters of genes up-regulated by ROS in Arabidopsis (Arabidopsis thaliana). We also found that the APETALA2/ethylene-responsive element binding factor6 (ERF6) could bind specifically to the ROSE7/GCC box. Coexpression of ERF6 enhanced luciferase activity driven by ROSE7. The deficient mutants of ERF6 showed growth retardation and higher sensitivity to photodamage. ERF6 interacted physically with mitogen-activated protein kinase6 (MPK6) and also served as a substrate of MPK6. MPK6-mediated ERF6 phosphorylation at both serine-266 and serine-269 affected the dynamic alternation of the ERF6 protein, which resulted in changes in ROS-responsive gene transcription. These data might provide new insight into the mechanisms that regulate ROS-responsive gene transcription via a complex of MPK6, ERF6, and the ROSE7/GCC box under oxidative stress or a fluctuating light environment.

Wang, Pengcheng; Du, Yanyan; Zhao, Xiaoliang; Miao, Yuchen; Song, Chun-Peng

2013-01-01

187

Ras-induced ROS upregulation affecting cell proliferation is connected with cell type-specific alterations of HSF1/SESN3/p21Cip1/WAF1 pathways.  

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Oncogenes of the RAS family regulate many of the cell's activities, including proliferation, survival and differentiation. Activating mutations in these genes are common events for many types of cancer. One of the contradictory points concerning the biological significance of Ras activation is its dual effect (pro- or anti-proliferative) on cell reproduction. One of mechanisms by which Ras proteins influence cell growth is a regulation of intracellular level of reactive oxygen species (ROS), second messengers affecting variety of cellular processes including cell proliferation. Recently it was shown that repression of SESN1 and SESN3 genes, whose protein products control regeneration of peroxiredoxins, can play a critical role in Ras-induced ROS upregulation. In the present study we have found that Ras-induced repression of SESN3 expression and ROS upregulation is mediated via the modifications of transcriptional activity of HSF1. Interestingly, mutant Ras overexpression altered the activity of HSF1 in opposite directions in different cell contexts, in particular in human normal fibroblasts and HaCaT immortalized keratinocytes, but these opposite changes caused similar repression of SESN3 expression followed by elevation of ROS content and inhibition of cell proliferation in corresponding cell types. The inhibitory effect on cell proliferation was mediated by upregulation of p21(Cip1/WAF1). Thus, HSF1/SESN3/ROS/p21(Cip1/WAF1)-mediated deceleration of cell growth may contribute to cell defense systems protecting the organism from excessive proliferation of cells that overexpress activated Ras oncoproteins. PMID:23388456

Zamkova, Maria; Khromova, Natalia; Kopnin, Boris P; Kopnin, Pavel

2013-02-06

188

ROS production and NF-?B activation triggered by RAC1 facilitate WNT-driven intestinal stem cell proliferation and colorectal cancer initiation.  

Science.gov (United States)

The Adenomatous Polyposis Coli (APC) gene is mutated in the majority of colorectal cancers (CRCs). Loss of APC leads to constitutively active WNT signaling, hyperproliferation, and tumorigenesis. Identification of pathways that facilitate tumorigenesis after APC loss is important for therapeutic development. Here, we show that RAC1 is a critical mediator of tumorigenesis after APC loss. We find that RAC1 is required for expansion of the LGR5 intestinal stem cell (ISC) signature, progenitor hyperproliferation, and transformation. Mechanistically, RAC1-driven ROS and NF-?B signaling mediate these processes. Together, these data highlight that ROS production and NF-?B activation triggered by RAC1 are critical events in CRC initiation. PMID:23665120

Myant, Kevin B; Cammareri, Patrizia; McGhee, Ewan J; Ridgway, Rachel A; Huels, David J; Cordero, Julia B; Schwitalla, Sarah; Kalna, Gabriela; Ogg, Erinn-Lee; Athineos, Dimitris; Timpson, Paul; Vidal, Marcos; Murray, Graeme I; Greten, Florian R; Anderson, Kurt I; Sansom, Owen J

2013-05-09

189

ROS Production and NF-?B Activation Triggered by RAC1 Facilitate WNT-Driven Intestinal Stem Cell Proliferation and Colorectal Cancer Initiation  

Science.gov (United States)

Summary The Adenomatous Polyposis Coli (APC) gene is mutated in the majority of colorectal cancers (CRCs). Loss of APC leads to constitutively active WNT signaling, hyperproliferation, and tumorigenesis. Identification of pathways that facilitate tumorigenesis after APC loss is important for therapeutic development. Here, we show that RAC1 is a critical mediator of tumorigenesis after APC loss. We find that RAC1 is required for expansion of the LGR5 intestinal stem cell (ISC) signature, progenitor hyperproliferation, and transformation. Mechanistically, RAC1-driven ROS and NF-?B signaling mediate these processes. Together, these data highlight that ROS production and NF-?B activation triggered by RAC1 are critical events in CRC initiation.

Myant, Kevin B.; Cammareri, Patrizia; McGhee, Ewan J.; Ridgway, Rachel A.; Huels, David J.; Cordero, Julia B.; Schwitalla, Sarah; Kalna, Gabriela; Ogg, Erinn-Lee; Athineos, Dimitris; Timpson, Paul; Vidal, Marcos; Murray, Graeme I.; Greten, Florian R.; Anderson, Kurt I.; Sansom, Owen J.

2013-01-01

190

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.  

UK PubMed Central (United Kingdom)

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.

Schallreuter KU; Salem MA; Gibbons NC; Martinez A; Slominski R; Lüdemann J; Rokos H

2012-06-01

191

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.  

Science.gov (United States)

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

2012-03-13

192

Heme modulates intestinal epithelial cell activation: involvement of NADPHox-derived ROS signaling.  

UK PubMed Central (United Kingdom)

In many gut chronic inflammatory conditions, intestinal epithelium (IE) is deprived of the protection of the mucus secreted by IE-specialized cells. In these events, bleeding and subsequent lysis of erythrocytes are common. This may lead to the release of high amounts of heme in the intestinal lumen, which interacts with IE. Previous works from our group have shown that heme itself is a proinflammatory molecule, activating a number of phlogistic signaling events in a nicotinamide adenine dinucleotide phosphate oxidase (NADPHox)-dependent manner. In this study, we aim to evaluate the effects of heme upon a well-established nontransformed small intestine epithelial cell lineage (IEC 6). Our results show that free heme evokes intracellular reactive oxygen species (ROS) production by IEC 6 cells, which is inhibited both by pharmacological inhibition with diphenyleneiodonium (10 ?M), a NADPHox inhibitor, and small interfering RNA-mediated suppression of NOX1, a constitutive NADPHox isoform present in intestinal epithelial cells. Focal adhesion kinase phosphorylation and actin cytoskeleton polymerization are also induced by heme in a NADPHox-dependent manner. Heme increases monolayer permeability and redistributes key modulators of cell-cell adhesion as zona occludens-1 and E-cadherin proteins via NADPHox signaling. Heme promotes IEC 6 cell migration and proliferation, phenomena also regulated by NADPHox-derived ROS. Heme, in NADPHox-activating concentrations, is able to induce mRNA expression of IL-6, a cytokine implicated in inflammatory and tumorigenic responses. These data indicate a prominent role for heme-derived signaling in the pathophysiology of intestinal mucosa dysfunction and address an important role of NADPHox activity on the pathogenesis of intestinal inflammatory conditions.

Barcellos-de-Souza P; Moraes JA; de-Freitas-Junior JC; Morgado-Díaz JA; Barja-Fidalgo C; Arruda MA

2013-01-01

193

Modulation of cardiac ryanodine receptor activity by ROS and RNS.  

UK PubMed Central (United Kingdom)

Calcium release through cardiac ryanodine receptors (RyR2) triggers heart muscle contraction. Reactive oxygen/nitrogen species (ROS/RNS), normally produced in the heart, promote endogenous RyR2 S-nitrosylation and S-glutathionylation. These reversible redox modifications increase RyR2 activity in vitro, and presumably also in vivo. RyR2 S-glutathionylation increases under physiologically relevant conditions (tachycardia and exercise), suggesting that cardiac cells utilize this redox modification to increase RyR2 activity under increased demand. In contrast, in vivo changes in RyR2 S-nitrosylation in response to physiological stimuli remain uncharacterized. The number and identity of the highly reactive RyR2 cysteine residues and the nature of the redox modification they undergo are presently unknown. Likewise, the physiological sources of ROS/RNS responsible for functionally relevant RyR2 redox modifications have not been completely identified. The redox state of RyR2 is altered in heart failure leading to enhanced RyR2 activity, which presumably contributes to decrease SR calcium content and induce other calcium release abnormalities observed in heart failure. Greater understanding of RyR2 redox modulation is necessary to counteract the deleterious consequences of RyR2 activity deregulation caused by oxidative stress.

Donoso P; Sanchez G; Bull R; Hidalgo C

2011-01-01

194

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

UK PubMed Central (United Kingdom)

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.

Yang CM; Hsieh HL; Lin CC; Shih RH; Chi PL; Cheng SE; Hsiao LD

2013-06-01

195

Recent Advances in Intracellular and In Vivo ROS Sensing: Focus on Nanoparticle and Nanotube Applications.  

UK PubMed Central (United Kingdom)

Reactive oxygen species (ROS) are increasingly being implicated in the regulation of cellular signaling cascades. Intracellular ROS fluxes are associated with cellular function ranging from proliferation to cell death. Moreover, the importance of subtle, spatio-temporal shifts in ROS during localized cellular signaling events is being realized. Understanding the biochemical nature of the ROS involved will enhance our knowledge of redox-signaling. An ideal intracellular sensor should therefore resolve real-time, localized ROS changes, be highly sensitive to physiologically relevant shifts in ROS and provide specificity towards a particular molecule. For in vivo applications issues such as bioavailability of the probe, tissue penetrance of the signal and signal-to-noise ratio also need to be considered. In the past researchers have heavily relied on the use of ROS-sensitive fluorescent probes and, more recently, genetically engineered ROS sensors. However, there is a great need to improve on current methods to address the above issues. Recently, the field of molecular sensing and imaging has begun to take advantage of the unique physico-chemical properties of nanoparticles and nanotubes. Here we discuss the recent advances in the use of these nanostructures as alternative platforms for ROS sensing, with particular emphasis on intracellular and in vivo ROS detection and quantification.

Uusitalo LM; Hempel N

2012-01-01

196

Recent Advances in Intracellular and In Vivo ROS Sensing: Focus on Nanoparticle and Nanotube Applications  

Directory of Open Access Journals (Sweden)

Full Text Available Reactive oxygen species (ROS) are increasingly being implicated in the regulation of cellular signaling cascades. Intracellular ROS fluxes are associated with cellular function ranging from proliferation to cell death. Moreover, the importance of subtle, spatio-temporal shifts in ROS during localized cellular signaling events is being realized. Understanding the biochemical nature of the ROS involved will enhance our knowledge of redox-signaling. An ideal intracellular sensor should therefore resolve real-time, localized ROS changes, be highly sensitive to physiologically relevant shifts in ROS and provide specificity towards a particular molecule. For in vivo applications issues such as bioavailability of the probe, tissue penetrance of the signal and signal-to-noise ratio also need to be considered. In the past researchers have heavily relied on the use of ROS-sensitive fluorescent probes and, more recently, genetically engineered ROS sensors. However, there is a great need to improve on current methods to address the above issues. Recently, the field of molecular sensing and imaging has begun to take advantage of the unique physico-chemical properties of nanoparticles and nanotubes. Here we discuss the recent advances in the use of these nanostructures as alternative platforms for ROS sensing, with particular emphasis on intracellular and in vivo ROS detection and quantification.

Larissa M. Uusitalo; Nadine Hempel

2012-01-01

197

Reactive oxygen species (ROS) and sensitization to TRAIL-induced apoptosis, in Bayesian network modelling of HeLa cell response to LY303511.  

UK PubMed Central (United Kingdom)

BACKGROUND: The compound LY303511 (LY30) has been proven to induce production of ROS and to sensitize cancer cells to TRAIL-induced apoptosis, but the mechanisms and mediators of LY30-induced effects are potentially complex. Bayesian networks are a modelling technique for making probabilistic inferences about complex networks of uncertain causality. METHODS: Fluorescent indicators for ROS, reactive nitrogen species (RNS), and free calcium were measured in time-series after LY30 treatment. This "correlative" dataset was used as input for Bayesian modelling to predict the causal dependencies among the measured species. Predictions were compared against a separate "causal" dataset, in which cells had been treated with FeTPPS to scavenge peroxynitrite, EGTA-am to chelate calcium, and Tiron to scavenge O(2)(-). Finally, cell viability measurements were integrated into an extended model of LY30 effects. RESULTS: LY30 treatment caused a rapid increase of ROS (measured by DCFDA) as well as a significant increase in RNS and calcium. Bayesian modelling predicted that Ca(2+)was a partial cause of the ROS induced by short incubations with LY30, and that RNS was strongly responsible for the ROS induced by long incubations with LY30. Validation experiments confirmed the predicted roles of RNS and calcium, and also demonstrated a causal role for O(2)(-). In cell viability experiments, the additive effects of calcium and peroxynitrite were responsible for 90% of LY30-mediated sensitization to TRAIL-induced apoptosis. CONCLUSIONS: We conclude that LY30 induces interdependent pathways of reactive species and stress signalling, with peroxynitrite and calcium contributing most significantly to apoptosis sensitization.

Tucker-Kellogg L; Shi Y; White JK; Pervaiz S

2012-11-01

198

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

Science.gov (United States)

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

2009-08-06

199

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

UK PubMed Central (United Kingdom)

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.

Cervantes-Sandoval I; Serrano-Luna Jde J; Meza-Cervantez P; Arroyo R; Tsutsumi V; Shibayama M

2009-11-01

200

Involvement of ROS in Curcumin-induced Autophagic Cell Death.  

UK PubMed Central (United Kingdom)

Many anticancer agents as well as ionizing radiation have been shown to induce autophagy which is originally described as a protein recycling process and recently reported to play a crucial role in various disorders. In HCT116 human colon cancer cells, we found that curcumin, a polyphenolic phytochemical extracted from the plant Curcuma longa, markedly induced the conversion of microtubule-associated protein 1 light chain 3 (LC3)-I to LC3-II and degradation of sequestome-1 (SQSTM1) which is a marker of autophagosome degradation. Moreover, we found that curcumin caused GFP-LC3 formation puncta, a marker of autophagosome, and decrease of GFP-LC3 and SQSTM1 protein level in GFP-LC3 expressing HCT116 cells. It was further confirmed that treatment of cells with hydrogen peroxide induced increase of LC3 conversion and decrease of GFP-LC3 and SQSTM1 levels, but these changes by curcumin were almost completely blocked in the presence of antioxidant, N-acetylcystein (NAC), indicating that curcumin leads to reactive oxygen species (ROS) production, which results in autophagosome development and autolysosomal degradation. In parallel with NAC, SQSTM1 degradation was also diminished by bafilomycin A, a potent inhibitor of autophagosome-lysosome fusion, and cell viability assay was further confirmed that cucurmin-induced cell death was partially blocked by bafilomycin A as well as NAC. We also observed that NAC abolished curcumin-induced activation of extracelluar signal-regulated kinases (ERK) 1/2 and p38 mitogen-activated protein kinases (MAPK), but not Jun N-terminal kinase (JNK). However, the activation of ERK1/2 and p38 MAPK seemed to have no effect on the curcumin-induced autophagy, since both the conversion of LC3 protein and SQSTM1 degradation by curcumin was not changed in the presence of NAC. Taken together, our data suggest that curcumin induced ROS production, which resulted in autophagic activation and concomitant cell death in HCT116 human colon cancer cell. However, ROS-dependent activation of ERK1/2 and p38 MAPK, but not JNK, might not be involved in the curcumin-induced autophagy.

Lee YJ; Kim NY; Suh YA; Lee C

2011-02-01

 
 
 
 
201

Involvement of ROS in Curcumin-induced Autophagic Cell Death.  

Science.gov (United States)

Many anticancer agents as well as ionizing radiation have been shown to induce autophagy which is originally described as a protein recycling process and recently reported to play a crucial role in various disorders. In HCT116 human colon cancer cells, we found that curcumin, a polyphenolic phytochemical extracted from the plant Curcuma longa, markedly induced the conversion of microtubule-associated protein 1 light chain 3 (LC3)-I to LC3-II and degradation of sequestome-1 (SQSTM1) which is a marker of autophagosome degradation. Moreover, we found that curcumin caused GFP-LC3 formation puncta, a marker of autophagosome, and decrease of GFP-LC3 and SQSTM1 protein level in GFP-LC3 expressing HCT116 cells. It was further confirmed that treatment of cells with hydrogen peroxide induced increase of LC3 conversion and decrease of GFP-LC3 and SQSTM1 levels, but these changes by curcumin were almost completely blocked in the presence of antioxidant, N-acetylcystein (NAC), indicating that curcumin leads to reactive oxygen species (ROS) production, which results in autophagosome development and autolysosomal degradation. In parallel with NAC, SQSTM1 degradation was also diminished by bafilomycin A, a potent inhibitor of autophagosome-lysosome fusion, and cell viability assay was further confirmed that cucurmin-induced cell death was partially blocked by bafilomycin A as well as NAC. We also observed that NAC abolished curcumin-induced activation of extracelluar signal-regulated kinases (ERK) 1/2 and p38 mitogen-activated protein kinases (MAPK), but not Jun N-terminal kinase (JNK). However, the activation of ERK1/2 and p38 MAPK seemed to have no effect on the curcumin-induced autophagy, since both the conversion of LC3 protein and SQSTM1 degradation by curcumin was not changed in the presence of NAC. Taken together, our data suggest that curcumin induced ROS production, which resulted in autophagic activation and concomitant cell death in HCT116 human colon cancer cell. However, ROS-dependent activation of ERK1/2 and p38 MAPK, but not JNK, might not be involved in the curcumin-induced autophagy. PMID:21461234

Lee, Youn Ju; Kim, Nam-Yi; Suh, Young-Ah; Lee, Chuhee

2011-02-28

202

Heterologous transmembrane signaling by a human insulin receptor-v-ros hybrid in Chinese hamster ovary cells  

International Nuclear Information System (INIS)

A hybrid receptor molecule composed of the extracellular ligand-binding domain of the human insulin receptor and the transmembrane and cytoplasmic (protein-tyrosine kinase) domains of the chicken sarcoma virus UR2 transforming protein p68/sup gag-ros/ has been constructed and expressed in Chinese hamster ovary (CHO) cells. The hybrid is processed normally into ? and hybrid ? subunits, is expressed on the cell surface at high levels, and binds insulin with near-wild-type affinity. Furthermore, insulin stimulates the phosphorylation on tyrosine resides of the hybrid ?-subunit in vivo and the phosphorylation of an exogeneous substrate [poly(Glu,Tyr)] in vitro. Thus the hybrid is capable of heterologous transmembrane signaling. However, the hybrid mediates neither the insulin-activated uptake of 2-deoxyglucose nor the incorporation of [3H]thymidine into DNA, suggesting that the physiological response(s) mediated by ligand-activated protein-tyrosine kinases may utilize distinct intracellular mechanisms for postreceptor signaling

1987-01-01

203

Regulation of energy metabolism in human cells in aging and diabetes: FoF(1), mtDNA, UCP, and ROS.  

Science.gov (United States)

Recent advances in bioenergetics consist of discoveries related to rotational coupling in ATP synthase (FoF(1)), uncoupling proteins (UCP), reactive oxygen species (ROS) and mitochondrial DNA (mtDNA). As shown in cloned sheep, mammalian genomes are composed of both nuclear DNA (nDNA) and maternal mtDNA. Oxidative phosphorylation (oxphos) varies greatly depending on cellular activities, and is regulated by both gene expression and the electrochemical potential difference of H(+) (Delta muH(+)). The expression of both mtDNA (by mtTFA) and nDNA for oxphos and UCP (by NRFs, etc.) is coordinated by a factor called PGC-1. The Delta muH(+) rotates an axis in FoF(1) that is regulated by inhibitors and ATP-sensitive K(+)-channels. We cultured human rho(o) cells (cells without mtDNA) in synthetic media and elucidated relationships among mtDNA, nDNA, Delta muH(+), UCPs, ROS, and apoptosis. These cells lack oxphos-dependent ROS formation and survive under conditions of high O(2). Cells cultured in the absence of ROS scavengers have proliferated for 40 years. UCPs lower Delta muH(+) and prevent ROS formation and resulting apoptosis. These results were applied to diabetology and gerontology. The pancreatic rho(o) cells did not secrete insulin, and mtDNA mutations caused diabetes, owing to the deficient Delta muH(+). Insulin resistance was closely related to UCPs and other energy regulators. The resulting high-glucose environment caused glycation of proteins and ROS-mediated apoptosis in vascular cells involved in diabetic complications. Telomeres, oxphos, and ROS are determinants in cellular aging. Cell division and ROS shortened telomeres and accelerated aging. In aged cells, Delta muH(+) was reduced by the slow respiration, and this change induced apoptosis. Cybrids made from aged cytoplasts and rho(o) cells showed that both decreased expression of nDNA, and somatic mutations of mtDNA are involved in the slowing of respiration in aged cells. PMID:10603304

Kagawa, Y; Cha, S H; Hasegawa, K; Hamamoto, T; Endo, H

1999-12-29

204

The proto-oncometabolite fumarate binds glutathione to amplify ROS-dependent signaling.  

Science.gov (United States)

The tricarboxylic acid cycle enzyme fumarate hydratase (FH) has been identified as a tumor suppressor in a subset of human renal cell carcinomas. Human FH-deficient cancer cells display high fumarate concentration and ROS levels along with activation of HIF-1. The underlying mechanisms by which FH loss increases ROS and HIF-1 are not fully understood. Here, we report that glutamine-dependent oxidative citric acid cycle metabolism is required to generate fumarate and increase ROS and HIF-1 levels. Accumulated fumarate directly bonds the antioxidant glutathione in vitro and in vivo to produce the metabolite succinated glutathione (GSF). GSF acts as an alternative substrate to glutathione reductase to decrease NADPH levels and enhance mitochondrial ROS and HIF-1 activation. Increased ROS also correlates with hypermethylation of histones in these cells. Thus, fumarate serves as a proto-oncometabolite by binding to glutathione which results in the accumulation of ROS. PMID:23747014

Sullivan, Lucas B; Martinez-Garcia, Eva; Nguyen, Hien; Mullen, Andrew R; Dufour, Eric; Sudarshan, Sunil; Licht, Jonathan D; Deberardinis, Ralph J; Chandel, Navdeep S

2013-06-06

205

The proto-oncometabolite fumarate binds glutathione to amplify ROS-dependent signaling.  

UK PubMed Central (United Kingdom)

The tricarboxylic acid cycle enzyme fumarate hydratase (FH) has been identified as a tumor suppressor in a subset of human renal cell carcinomas. Human FH-deficient cancer cells display high fumarate concentration and ROS levels along with activation of HIF-1. The underlying mechanisms by which FH loss increases ROS and HIF-1 are not fully understood. Here, we report that glutamine-dependent oxidative citric acid cycle metabolism is required to generate fumarate and increase ROS and HIF-1 levels. Accumulated fumarate directly bonds the antioxidant glutathione in vitro and in vivo to produce the metabolite succinated glutathione (GSF). GSF acts as an alternative substrate to glutathione reductase to decrease NADPH levels and enhance mitochondrial ROS and HIF-1 activation. Increased ROS also correlates with hypermethylation of histones in these cells. Thus, fumarate serves as a proto-oncometabolite by binding to glutathione which results in the accumulation of ROS.

Sullivan LB; Martinez-Garcia E; Nguyen H; Mullen AR; Dufour E; Sudarshan S; Licht JD; Deberardinis RJ; Chandel NS

2013-07-01

206

Metal-Sulfate Induced Generation of ROS in Human Brain Cells: Detection Using an Isomeric Mixture of 5- and 6-Carboxy-2?,7?-Dichlorofluorescein Diacetate (Carboxy-DCFDA) as a Cell Permeant Tracer  

Directory of Open Access Journals (Sweden)

Full Text Available Evolution of reactive oxygen species (ROS), generated during the patho-physiological stress of nervous tissue, has been implicated in the etiology of several progressive human neurological disorders including Alzheimer’s disease (AD) and amylotrophic lateral sclerosis (ALS). In this brief communication we used mixed isomers of 5-(and-6)-carboxy-2?,7?-dichlorofluorescein diacetate (carboxy-DCFDA; C25H14Cl2O9; MW 529.3), a novel fluorescent indicator, to assess ROS generation within human neuronal-glial (HNG) cells in primary co-culture. We introduced pathological stress using the sulfates of 12 environmentally-, industrially- and agriculturally-relevant divalent and trivalent metals including Al, Cd, Cu, Fe, Hg, Ga, Mg, Mn, Ni, Pb, Sn and Zn. In this experimental test system, of all the metal sulfates analyzed, aluminum sulfate showed by far the greatest ability to induce intracellular ROS. These studies indicate the utility of using isomeric mixtures of carboxy-H2DCFDA diacetates as novel and highly sensitive, long-lasting, cell-permeant, fluorescein-based tracers for quantifying ROS generation in intact, metabolizing human brain cells, and in analyzing the potential epigenetic contribution of different metal sulfates to ROS-generation and ROS-mediated neurological dysfunction.

Aileen I. Pogue; Brandon M. Jones; Surjyadipta Bhattacharjee; Maire E. Percy; Yuhai Zhao; Walter J. Lukiw

2012-01-01

207

Capsaicin stimulates glucose uptake in C2C12 muscle cells via the reactive oxygen species (ROS)/AMPK/p38 MAPK pathway.  

Science.gov (United States)

Capsaicin has been reported to regulate blood glucose levels and to ameliorate insulin resistance in obese mice. This study demonstrates that capsaicin increases glucose uptake directly by activating AMP-activated protein kinase (AMPK) in C2C12 muscle cells, which manifested as an attenuation of glucose uptake when compound C, an AMPK inhibitor, was co-administered with capsaicin. However, the insulin signaling molecules insulin receptor substrate-1 (IRS-1) and Akt were not affected by capsaicin. Additional results showed that p38 mitogen-activated protein kinase (MAPK) is also involved in capsaicin-induced glucose transport downstream of AMPK because capsaicin increased p38 MAPK phosphorylation significantly and its specific inhibitor SB203580 inhibited capsaicin-mediated glucose uptake. Treatment with an AMPK inhibitor reduced p38 MAPK phosphorylation, but the p38 MAPK inhibitor had no effect on AMPK. Capsaicin stimulated ROS generation in C2C12 muscle cells, and when ROS were captured using the nonspecific antioxidant NAC, the increase in both capsaicin-induced AMPK phosphorylation and capsaicin-induced glucose uptake was attenuated, suggesting that ROS function as an upstream activator of AMPK. Taken together, these results suggest that capsaicin, independent of insulin, increases glucose uptake via ROS generation and consequent AMPK and p38 MAPK activations. PMID:23958300

Kim, Soon-Hee; Hwang, Jin-Taek; Park, Hee Sook; Kwon, Dae Young; Kim, Myung-Sunny

2013-08-16

208

Capsaicin stimulates glucose uptake in C2C12 muscle cells via the reactive oxygen species (ROS)/AMPK/p38 MAPK pathway.  

UK PubMed Central (United Kingdom)

Capsaicin has been reported to regulate blood glucose levels and to ameliorate insulin resistance in obese mice. This study demonstrates that capsaicin increases glucose uptake directly by activating AMP-activated protein kinase (AMPK) in C2C12 muscle cells, which manifested as an attenuation of glucose uptake when compound C, an AMPK inhibitor, was co-administered with capsaicin. However, the insulin signaling molecules insulin receptor substrate-1 (IRS-1) and Akt were not affected by capsaicin. Additional results showed that p38 mitogen-activated protein kinase (MAPK) is also involved in capsaicin-induced glucose transport downstream of AMPK because capsaicin increased p38 MAPK phosphorylation significantly and its specific inhibitor SB203580 inhibited capsaicin-mediated glucose uptake. Treatment with an AMPK inhibitor reduced p38 MAPK phosphorylation, but the p38 MAPK inhibitor had no effect on AMPK. Capsaicin stimulated ROS generation in C2C12 muscle cells, and when ROS were captured using the nonspecific antioxidant NAC, the increase in both capsaicin-induced AMPK phosphorylation and capsaicin-induced glucose uptake was attenuated, suggesting that ROS function as an upstream activator of AMPK. Taken together, these results suggest that capsaicin, independent of insulin, increases glucose uptake via ROS generation and consequent AMPK and p38 MAPK activations.

Kim SH; Hwang JT; Park HS; Kwon DY; Kim MS

2013-09-01

209

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

210

N,N-dimethyl phytosphingosine induces caspase-8-dependent cytochrome c release and apoptosis through ROS generation in human leukemia cells  

International Nuclear Information System (INIS)

N,N-dimethyl phytosphingosine (DMPS) blocks the conversion of sphingosine to sphingosine-1-phosphate (S1P) by the enzyme sphingosine kinase (SK). In this study, we elucidated the apoptotic mechanisms of DMPS action on a human leukemia cell line using functional pharmacologic and genetic approaches. First, we demonstrated that DMPS-induced apoptosis is evidenced by nuclear morphological change, distinct internucleosomal DNA fragmentation, and an increased sub-G1 cell population. DMPS treatment led to the activation of caspase-9 and caspase-3, accompanied by the cleavage of poly(ADP-ribose) polymerase (PARP) and led to cytochrome c release, depolarization of the mitochondrial membrane potential, and downregulation of the anti-apoptotic members of the bcl-2 family. Ectopic expression of bcl-2 and bcl-xL conferred resistance of HL-60 cells to DMPS-induced cell death, suggesting that DMPS-induced apoptosis occurs predominantly through the activation of the intrinsic mitochondrial pathway. We also observed that DMPS activated the caspase-8-Bid-Bax pathway and that the inhibition of caspase-8 by z-IETD-fmk or small interfering RNA suppressed the cleavage of Bid, cytochrome c release, caspase-3 activation, and apoptotic cell death. In addition, cells subjected to DMPS exhibited significantly increased reactive oxygen species (ROS) generation, and ROS scavengers, such as quercetin and Tiron, but not N-acetylcysteine (NAC), inhibited DMPS-induced activations of caspase-8, -3 and subsequent apoptotic cell death, indicating the role of ROS in caspase-8-mediated apoptosis. Taken together, these results indicate that caspase-8 acts upstream of caspase-3, and that the caspase-8-mediated mitochondrial pathway is important in DMPS-induced apoptosis. Our results also suggest that ROS are critical regulators of caspase-8-mediated apoptosis in DMPS-treated leukemia cells.

2009-08-15

211

P53 activation plays a crucial role in silibinin induced ROS generation via PUMA and JNK.  

Science.gov (United States)

Silibinin is an active constituent extracted from blessed milk thistle (Silybum marianum). Our previous study demonstrated that silibinin induced autophagy and apoptosis via reactive oxygen species (ROS) generation in HeLa cells. In this study, we investigated whether the autophagy- and apoptosis-associated molecules also involved in ROS generation. Silibinin promoted the expression phosphorylated-p53 (p-p53) in a dose-dependent manner. Pifithrin-? (PFT-?), a specific inhibitor of p53, reduced ROS production and reversed silibinin's growth-inhibitory effect. The ROS scavenger N-acetyl cysteine (NAC) attenuated silibinin-induced up-regulation of p-p53 expression, suggesting that p53 might be regulated by ROS and forms a positive feedback loop with ROS. On the other hand, silibinin dose-dependently promoted the expression of phosphorylated-c-Jun N-terminal kinase (p-JNK). Inhibition of JNK by SP600125 decreased ROS generation. NAC down-regulated the expression of p-JNK, indicating that JNK could be activated by ROS. Activation of p53 was suppressed by SP600125 and expression of p-JNK was inhibited by PFT-?, therefore silibinin might activate a ROS-JNK-p53 cycle to induce cell death. Silibinin up-regulated the PUMA and Bax expressions and down-regulated the mitochondrial membrane potential (MMP) level. PFT-? reduced the expression of PUMA and Bax. These results showed that p53 could interfere with mitochondrial functions such as MMP via PUMA pathways, thus resulting in ROS generation. In order to elucidate the functions of p53 in silibinin induced ROS generation, we have chosen the A431 cells (human epithelial carcinoma) because they lack p53 activity (p53His273 mutation). Interestingly, silibinin did not up-regulate the ROS level in A431 cells but lower the ROS level. PFT-? had no influence on ROS level in A431 cells. p53 activation plays a crucial role in silibinin induced ROS generation. PMID:22283740

Fan, Simiao; Qi, Min; Yu, Yang; Li, Lihua; Yao, Guodong; Tashiro, Shin-ichi; Onodera, Satoshi; Ikejima, Takashi

2012-02-02

212

P53 activation plays a crucial role in silibinin induced ROS generation via PUMA and JNK.  

UK PubMed Central (United Kingdom)

Silibinin is an active constituent extracted from blessed milk thistle (Silybum marianum). Our previous study demonstrated that silibinin induced autophagy and apoptosis via reactive oxygen species (ROS) generation in HeLa cells. In this study, we investigated whether the autophagy- and apoptosis-associated molecules also involved in ROS generation. Silibinin promoted the expression phosphorylated-p53 (p-p53) in a dose-dependent manner. Pifithrin-? (PFT-?), a specific inhibitor of p53, reduced ROS production and reversed silibinin's growth-inhibitory effect. The ROS scavenger N-acetyl cysteine (NAC) attenuated silibinin-induced up-regulation of p-p53 expression, suggesting that p53 might be regulated by ROS and forms a positive feedback loop with ROS. On the other hand, silibinin dose-dependently promoted the expression of phosphorylated-c-Jun N-terminal kinase (p-JNK). Inhibition of JNK by SP600125 decreased ROS generation. NAC down-regulated the expression of p-JNK, indicating that JNK could be activated by ROS. Activation of p53 was suppressed by SP600125 and expression of p-JNK was inhibited by PFT-?, therefore silibinin might activate a ROS-JNK-p53 cycle to induce cell death. Silibinin up-regulated the PUMA and Bax expressions and down-regulated the mitochondrial membrane potential (MMP) level. PFT-? reduced the expression of PUMA and Bax. These results showed that p53 could interfere with mitochondrial functions such as MMP via PUMA pathways, thus resulting in ROS generation. In order to elucidate the functions of p53 in silibinin induced ROS generation, we have chosen the A431 cells (human epithelial carcinoma) because they lack p53 activity (p53His273 mutation). Interestingly, silibinin did not up-regulate the ROS level in A431 cells but lower the ROS level. PFT-? had no influence on ROS level in A431 cells. p53 activation plays a crucial role in silibinin induced ROS generation.

Fan S; Qi M; Yu Y; Li L; Yao G; Tashiro S; Onodera S; Ikejima T

2012-03-01

213

ROS inhibitor N-acetyl-L-cysteine antagonizes the activity of proteasome inhibitors.  

Science.gov (United States)

NAC (N-acetyl-L-cysteine) is commonly used to identify and test ROS (reactive oxygen species) inducers, and to inhibit ROS. In the present study, we identified inhibition of proteasome inhibitors as a novel activity of NAC. Both NAC and catalase, another known scavenger of ROS, similarly inhibited ROS levels and apoptosis associated with H2O2. However, only NAC, and not catalase or another ROS scavenger Trolox, was able to prevent effects linked to proteasome inhibition, such as protein stabilization, apoptosis and accumulation of ubiquitin conjugates. These observations suggest that NAC has a dual activity as an inhibitor of ROS and proteasome inhibitors. Recently, NAC was used as a ROS inhibitor to functionally characterize a novel anticancer compound, piperlongumine, leading to its description as a ROS inducer. In contrast, our own experiments showed that this compound depicts features of proteasome inhibitors including suppression of FOXM1 (Forkhead box protein M1), stabilization of cellular proteins, induction of ROS-independent apoptosis and enhanced accumulation of ubiquitin conjugates. In addition, NAC, but not catalase or Trolox, interfered with the activity of piperlongumine, further supporting that piperlongumine is a proteasome inhibitor. Most importantly, we showed that NAC, but not other ROS scavengers, directly binds to proteasome inhibitors. To our knowledge, NAC is the first known compound that directly interacts with and antagonizes the activity of proteasome inhibitors. Taken together, the findings of the present study suggest that, as a result of the dual nature of NAC, data interpretation might not be straightforward when NAC is utilized as an antioxidant to demonstrate ROS involvement in drug-induced apoptosis. PMID:23772801

Halasi, Marianna; Wang, Ming; Chavan, Tanmay S; Gaponenko, Vadim; Hay, Nissim; Gartel, Andrei L

2013-09-01

214

ROS inhibitor N-acetyl-L-cysteine antagonizes the activity of proteasome inhibitors.  

UK PubMed Central (United Kingdom)

NAC (N-acetyl-L-cysteine) is commonly used to identify and test ROS (reactive oxygen species) inducers, and to inhibit ROS. In the present study, we identified inhibition of proteasome inhibitors as a novel activity of NAC. Both NAC and catalase, another known scavenger of ROS, similarly inhibited ROS levels and apoptosis associated with H2O2. However, only NAC, and not catalase or another ROS scavenger Trolox, was able to prevent effects linked to proteasome inhibition, such as protein stabilization, apoptosis and accumulation of ubiquitin conjugates. These observations suggest that NAC has a dual activity as an inhibitor of ROS and proteasome inhibitors. Recently, NAC was used as a ROS inhibitor to functionally characterize a novel anticancer compound, piperlongumine, leading to its description as a ROS inducer. In contrast, our own experiments showed that this compound depicts features of proteasome inhibitors including suppression of FOXM1 (Forkhead box protein M1), stabilization of cellular proteins, induction of ROS-independent apoptosis and enhanced accumulation of ubiquitin conjugates. In addition, NAC, but not catalase or Trolox, interfered with the activity of piperlongumine, further supporting that piperlongumine is a proteasome inhibitor. Most importantly, we showed that NAC, but not other ROS scavengers, directly binds to proteasome inhibitors. To our knowledge, NAC is the first known compound that directly interacts with and antagonizes the activity of proteasome inhibitors. Taken together, the findings of the present study suggest that, as a result of the dual nature of NAC, data interpretation might not be straightforward when NAC is utilized as an antioxidant to demonstrate ROS involvement in drug-induced apoptosis.

Halasi M; Wang M; Chavan TS; Gaponenko V; Hay N; Gartel AL

2013-09-01

215

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

2005-01-01

216

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

217

Proteomic analysis revealed association of aberrant ROS signaling with suberoylanilide hydroxamic acid-induced autophagy in Jurkat T-leukemia cells.  

UK PubMed Central (United Kingdom)

Suberoylanilide hydroxamic acid (SAHA) is a newly emerging histone deacetylase inhibitor (HDACi) and has been approved in phase II clinical trials for treating patients with cutaneous T-cell lymphoma. Autophagy is a conserved self-digestion process that degrades cytoplasmic materials and recycles long-lived proteins and organelles within cells. In this study, we demonstrate that SAHA stimulates autophagy in Jurkat T-leukemia cells, which was evidenced by the appearance of autophagic vacuoles, formation of acidic vesicular organelles, recruitment of LC3-II to the autophagosomes and conversion of LC3-I to LC3-II . Moreover, SAHA treatment upregulated expression of Beclin 1 and Atg7 and promoted formation of the Atg12-Atg5 conjugate. Furthermore, inhibition of autophagy by chloroquine (CQ) enhanced SAHA-induced apoptosis. To determine the underlying mechanism of SAHA-induced autophagy, two complementary proteomic approaches (2-DE and SILAC), coupled with ESI-Q-TOF MS/MS analysis are utilized to profile differentially expressed proteins between control and SAHA-treated Jurkat T-leukemia cells. In total, 72 proteins were identified with significant alterations. Cluster analysis of the changed proteins reveal several groups of enzymes associated with energy metabolism, anti-oxidative stress and cellular redox control, which suggested an abnormal reactive oxygen species (ROS) production in SAHA-treated Jurkat T-leukemia cells. These observations were further confirmed by ROS chemiluminescence assay. Mechanistic studies revealed that SAHA-triggered autophagy was mediated by ROS production, which could be attenuated by N-acetyl cysteine (NAC), a ROS inhibitor. Finally, we illustrated that Akt-mTOR signaling, a major suppressive cascade of autophagy, was inactivated by SAHA treatment. Taken together, our study identifies autophagy as a reaction to counter increased ROS and is thus involved as a cellular prosurvival mechanism in response to SAHA treatment.

Li J; Liu R; Lei Y; Wang K; Lau QC; Xie N; Zhou S; Nie C; Chen L; Wei Y; Huang C

2010-08-01

218

Anti-nephrolithic potential of resveratrol via inhibition of ROS, MCP-1, hyaluronan and osteopontin in vitro and in vivo.  

UK PubMed Central (United Kingdom)

Background: Though resveratrol is known to have anti-cancer, anti-diabetic, anti-oxidant and anti-inflammatory activities, the inhibitory mechanism of resveratrol in kidney stone formation has not been elucidated so far. Method: ELISA, flow cytometry, RT-PCR, and western blotting were performed. Human renal epithelial cells (HRCs) and rats with ethylene glycol (EG)-induced kidney stones were used. Results: A wound healing assay revealed that resveratrol significantly inhibited the oxalate-mediated migration of HRCs, considering oxalate mediates kidney stone formation. Also, resveratrol suppressed the mRNA expression of nicotinamide adenine dinucleotide phosphate hydrogen (NADPH) oxidase subunits such as p22(phox) and p47(phox), monocyte chemoattractant protein 1 (MCP-1) and osteopontin (OPN) in oxalate-treated HRCs. Furthermore, western blotting showed that resveratrol downregulated the expression of MCP-1-related proteins including transforming growth factor(TGF-?1), TGFR-I or II and hyaluronan in oxalate-treated HRCs. Consistently, resveratrol reduced oxalate-mediated production of reactive oxygen species (ROS) and malondialdehyde (MDA) in oxalate-treated HRCs, while the activities of anti-oxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) were enhanced by resveratrol in HRCs and EG-treated kidneys of rats. Consistently, resveratrol significantly reduced the number of urine calcium oxalate crystals and serum MDA, and attenuated the expression of OPN and hyaluroran in EG-treated rats. Conclusions: Our findings suggest that resveratrol exerts anti-nephrolithic potential via inhibition of ROS, MCP-1 hyaluronan and OPN signaling.

Hong SH; Lee HJ; Sohn EJ; Ko HS; Shim BS; Ahn KS; Kim SH

2013-01-01

219

RO(S^1)-graded TR-groups of F_p, Z and \\ell  

CERN Document Server

We give an algorithm for calculating the RO(S^1)-graded TR-groups of F_p, completing the calculation started in [Ge08]. We also calculate the RO(S^1)-graded TR-groups of Z with mod p coefficients and of the Adams summand \\ell of connective complex K-theory with V(1)-coefficients.

Angeltveit, Vigleik

2008-01-01

220

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

Science.gov (United States)

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.

Lipovsky, Anat; Nitzan, Yeshayahu; Gedanken, Aharon; Lubart, Rachel

2011-03-01

 
 
 
 
221

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

222

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

223

Phagocytic uptake and ROS-mediated cytotoxicity in human hepatic cell line of amphiphilic polyphosphazene nanoparticles.  

UK PubMed Central (United Kingdom)

The pH-responsive amphiphilic polyphosphazenes bearing N,N-diisopropylethylenediamine (DPA) have been proven to be promising nanovehicles for drug antitumor therapy. To further modify these amphiphilic polyphosphazenes with fluorescent labeling agent or other biochemical functional groups, serine methyl ester containing active chemical group ?NH(2) was chosen to be introduced to get a novel polymer [NP(PEG)(0.24) (DPA)(0.5)(SME)(1.26) (n) (PDS-NH(2) ). Considering the possible toxic effect of -NH(2) group, the biocompatibility in bloodstream and nanotoxicity on human normal hepatic L-02 cells was evaluated in this study. The polymer [NP(PEG)(0.24)(DPA)(0.5)(SME-BOC)(1.26)](n) (PDS-BOC) linked with tert-butyloxycarbonyl groups to protect and hide -NH(2) group was applied as the comparison. First, the bovine serum albumin (BSA) adsorption and phagocytic uptake behavior in human THP-1 macrophages were performed. The results suggested that only a minor percentage of the nanoparticles were involved in BSA binding and phagocytic uptake as the result of PEGylation on the particulate surface. To determine the nanotoxicity on human normal hepatic L-02 cells, we measured cell viability, apoptosis and necrosis, reactive oxygen species generation, the loss of mitochondrial membrane potential, and the levels of the apoptotic signaling proteins in L-02 cells after the cells being exposed to nanoparticles of different concentrations (0.1, 0.2, and 0.5 mg/mL) for 24 h. Our data indicated that the two nanoparticles induced cytotoxicity in a dose-dependent manner; PDS-NH(2) caused more cytotoxicity than PDS-BOC as a result of -NH(2) exposure. The increased expression of caspase-3 and caspase-9 suggested that they triggered apoptosis through mitochondria-dependent pathways in L-02 cells.

Qiu L; Chen Y; Gao M; Zheng C; Zhao Q

2013-01-01

224

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

Directory of Open Access Journals (Sweden)

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.

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

2005-01-01

225

Redox Signaling Mediated by the Gut Microbiota.  

UK PubMed Central (United Kingdom)

Abstract The microbiota that occupies the mammalian intestine can modulate a range of physiological functions, including control over immune responses, epithelial barrier function, and cellular proliferation. While commensal prokaryotic organisms are well known to stimulate inflammatory signaling networks, less is known about control over homeostatic pathways. Recent work has shown that gut epithelia contacted by enteric commensal bacteria rapidly generate reactive oxygen species (ROS). While the induced production of ROS in professional phagocytes via stimulation of formyl peptide receptors (FPRs) and activation of NADPH oxidase 2 (Nox2) is a well-studied process, ROS are also similarly elicited in other cell types, including intestinal epithelia, in response to microbial signals via FPRs and the epithelial NADPH oxidase 1 (Nox1). ROS generated by Nox enzymes have been shown to function as critical second messengers in multiple signal transduction pathways via the rapid and transient oxidative inactivation of a distinct class of sensor proteins bearing oxidant-sensitive thiol groups. These redox sensitive proteins include tyrosine phosphatases that serve as regulators of MAP kinase pathways, focal adhesion kinase, as well as components involved NF-?B activation. As microbial-elicited ROS has been shown to stimulate cellular proliferation and motility, and to modulate innate immune signaling, we hypothesize that many of the established effects of the normal microbiota on intestinal physiology may be at least partially mediated by this ROS-dependent mechanism.

Neish AS

2013-08-01

226

Effect of Methyl Jasmonate on antioxidative enzyme activities and on the contents of ROS and H2O2 in Ricinus communis leaves  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english Jasmonates are a class of plant hormones that mediate various aspects in gene and metabolic regulation, defense, stress responses, reproduction and, possibly, communication. Oxidative stress stimulates synthesis of antioxidant metabolites and enhances antioxidant enzyme activities that could protect plant tissues. The aim of this study was to verify the effects of methyl jasmonate (JAME) treatment on the reactive oxygen species (ROS) and on the activities of H2O2 scavengi (more) ng enzymes, such as superoxide dismutase (SOD; EC 1.15.1.1), catalase (CAT; EC 1.11.1.6), ascorbate peroxidase (APX EC; 1.11.1.1), and guaiacol peroxidase (GPX; EC 1.11.1.7) in Ricinus communis leaves. The activity of CAT and GPX was transient while SOD activity decreased and APX increased after treatment with JAME. In addition, JAME exposure induced ROS accumulation.

Soares, Alexandra Martins dos Santos; Souza, Thiago Freitas de; Jacinto, Tânia; Machado, Olga Lima Tavares

2010-01-01

227

Effect of Methyl Jasmonate on antioxidative enzyme activities and on the contents of ROS and H2O2 in Ricinus communis leaves  

Directory of Open Access Journals (Sweden)

Full Text Available Jasmonates are a class of plant hormones that mediate various aspects in gene and metabolic regulation, defense, stress responses, reproduction and, possibly, communication. Oxidative stress stimulates synthesis of antioxidant metabolites and enhances antioxidant enzyme activities that could protect plant tissues. The aim of this study was to verify the effects of methyl jasmonate (JAME) treatment on the reactive oxygen species (ROS) and on the activities of H2O2 scavenging enzymes, such as superoxide dismutase (SOD; EC 1.15.1.1), catalase (CAT; EC 1.11.1.6), ascorbate peroxidase (APX EC; 1.11.1.1), and guaiacol peroxidase (GPX; EC 1.11.1.7) in Ricinus communis leaves. The activity of CAT and GPX was transient while SOD activity decreased and APX increased after treatment with JAME. In addition, JAME exposure induced ROS accumulation.

Alexandra Martins dos Santos Soares; Thiago Freitas de Souza; Tânia Jacinto; Olga Lima Tavares Machado

2010-01-01

228

ROS signaling pathways and biological rhythms: perspectives in crustaceans.  

UK PubMed Central (United Kingdom)

This work reviews concepts regarding the endogenous circadian clock and the relationship between oxidative stress (OS), light and entrainment in different organisms including crustaceans, particularly crayfish. In the first section, the molecular control of circadian rhythms in invertebrates, particularly in Drosophila, is reviewed, and this model is contrasted with recent reports on the circadian genes and proteins in crayfish. Second, the redox mechanisms and signaling pathways that participate in the entrainment of the circadian clock in different organisms are reviewed. Finally, the light signals and transduction pathways involved in the entrainment of the circadian clock, specifically in relation to cryptochromes (CRYs) and their dual role in the circadian clock of different animal groups and their possible relationship to the circadian clock and redox mechanisms in crustaceans is discussed. The relationship between metabolism, ROS signals and transcription factors, such as HIF-1 alpha in crayfish, as well as the possibility that HIF-1 alpha participates in the regulation of circadian control genes (ccgs) in crustaceans is discussed.

Fanjul-Moles ML

2013-01-01

229

Viscolin reduces VCAM-1 expression in TNF-?-treated endothelial cells via the JNK/NF-?B and ROS pathway.  

UK PubMed Central (United Kingdom)

Viscolin, a major active component in a chloroform extract of Viscum coloratum, has antioxidative and anti-inflammatory properties. We focused on its effects on the expression of vascular cell adhesion molecule-1 (VCAM-1) in tumor necrosis factor-? (TNF-?)-treated human umbilical vein endothelial cells (HUVECs). The TNF-?-induced expression of VCAM-1 was significantly reduced by respectively 38±7 or 34±16% when HUVECs were pretreated with 10 or 30?M viscolin, as shown by Western blotting, and was also significantly reduced by pretreatment with the antioxidants N-acetylcysteine, diphenylene iodonium chloride, and apocynin. Viscolin also reduced TNF-?-induced VCAM-1 mRNA expression and promoter activity, decreased reactive oxygen species (ROS) production, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity, and significantly reduced the binding of monocytes to TNF-?-stimulated HUVECs. The attenuation of TNF-?-induced VCAM-1 expression and cell adhesion was partly mediated by a decrease in JNK phosphorylation. Furthermore, viscolin reduced VCAM-1 expression in the aorta of TNF-?-treated mice in vivo. Taken together, these data show that viscolin inhibits TNF-?-induced JNK phosphorylation, nuclear translocation of NF-?B p65, and ROS generation and thereby suppresses VCAM-1 expression, resulting in reduced adhesion of leukocytes. These results also suggest that viscolin may prevent the development of atherosclerosis and inflammatory responses.

Liang CJ; Wang SH; Chen YH; Chang SS; Hwang TL; Leu YL; Tseng YC; Li CY; Chen YL

2011-10-01

230

Viscolin reduces VCAM-1 expression in TNF-?-treated endothelial cells via the JNK/NF-?B and ROS pathway.  

Science.gov (United States)

Viscolin, a major active component in a chloroform extract of Viscum coloratum, has antioxidative and anti-inflammatory properties. We focused on its effects on the expression of vascular cell adhesion molecule-1 (VCAM-1) in tumor necrosis factor-? (TNF-?)-treated human umbilical vein endothelial cells (HUVECs). The TNF-?-induced expression of VCAM-1 was significantly reduced by respectively 38±7 or 34±16% when HUVECs were pretreated with 10 or 30?M viscolin, as shown by Western blotting, and was also significantly reduced by pretreatment with the antioxidants N-acetylcysteine, diphenylene iodonium chloride, and apocynin. Viscolin also reduced TNF-?-induced VCAM-1 mRNA expression and promoter activity, decreased reactive oxygen species (ROS) production, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity, and significantly reduced the binding of monocytes to TNF-?-stimulated HUVECs. The attenuation of TNF-?-induced VCAM-1 expression and cell adhesion was partly mediated by a decrease in JNK phosphorylation. Furthermore, viscolin reduced VCAM-1 expression in the aorta of TNF-?-treated mice in vivo. Taken together, these data show that viscolin inhibits TNF-?-induced JNK phosphorylation, nuclear translocation of NF-?B p65, and ROS generation and thereby suppresses VCAM-1 expression, resulting in reduced adhesion of leukocytes. These results also suggest that viscolin may prevent the development of atherosclerosis and inflammatory responses. PMID:21767632

Liang, Chan-Jung; Wang, Shu-Huei; Chen, Yung-Hsiang; Chang, Shih-Sheng; Hwang, Tong-Long; Leu, Yann-Lii; Tseng, Ying-Chih; Li, Chi-Yuan; Chen, Yuh-Lien

2011-07-06

231

Herbacetin induces apoptosis in HepG2 cells: Involvements of ROS and PI3K/Akt pathway.  

UK PubMed Central (United Kingdom)

Herbacetin (HER) is a natural flavonoid compound that can be extracted from Ramose Scouring Rush Herb, and its biological and pharmacological activities lack of corresponding attention. In this study, the apoptotic effect of HER against the human hepatoma cell line (HepG2) was investigated. The results showed that HepG2 cells apoptosis occurred in a dose-dependent manner within 48h incubated with HER, which was confirmed by DNA fragmentation, nuclear shrinkage, and poly (ADP-ribose) polymerase (PARP) cleavage. HER at 25-100?M induced a mitochondria-dependent apoptotic pathway associated with Bcl-2/Bax ratio decrease, mitochondrial membrane potential (??) collapse, cytochrome c release, and caspase-3 activation. Increasing expression of peroxisome proliferator-activated receptor-? coactivator 1? (PGC-1?) was also observed in HER-treated cells. Furthermore, the addition of a ROS inhibitor (N-Acetyl-l-cysteine, NAC) significantly attenuated the apoptosis induced by HER and also blocked the expression of PGC-1? protein. Additionally, HER effectively inhibited the phosphorylation of Akt and the phosphatidylinositol-3 kinase (PI3K) inhibitor LY294002 increased the inhibition effect of HER on Akt phosphorylation. These findings provide evidences that HER induces HepG2 apoptosis in a ROS-mediated mitochondria-dependent manner that correlate with the inactivation of the PI3K/Akt pathway.

Qiao Y; Xiang Q; Yuan L; Xu L; Liu Z; Liu X

2013-01-01

232

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

UK PubMed Central (United Kingdom)

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.

Cemeli E; Anderson D

2011-01-01

233

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

Directory of Open Access Journals (Sweden)

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.

Eduardo Cemeli; Diana Anderson

2011-01-01

234

Effect of CRH on NO bioavailability, ROS production and antioxidant defense systems in endothelial EAhy926 cells.  

UK PubMed Central (United Kingdom)

Local or 'Immune' Corticotropin-Releasing Hormone (CRH) is secreted in peripheral tissues and plays a direct immunomodulatory role as an endocrine or paracrine mediator of inflammation. The present study was undertaken to determine whether CRH affects the endothelial redox state. Accordingly, intracellular reactive oxygen species (ROS) content and peroxynitrite levels, endothelial nitric oxide synthase (eNOS) activity and nitric oxide (NO) levels as well as catalase activity, superoxide dismutase (SOD) activity and glutathione (GSH) levels were measured in the presence or absence of selective CRH receptor-1 and CRH receptor-2 inhibitors in endothelial EAhy926 cells exposed in vitro in 10(-7) M CRH for 2 h. CRH acting through both receptors induced a significant increase of ROS content (p < 0.001), catalase activity (p < 0.001) and SOD activity (p < 0.001), accompanied by a simultaneous significant decrease of eNOS activity and NO levels (p < 0.001), as well as a significant increase in nitrotyrosine (peroxynitrite) levels (p < 0.05). The data indicate that CRH may act as a regulator of pro-inflammatory mechanisms inducing adaptation of endothelial cell function to local stress.

Gougoura S; Liakos P; Koukoulis GN

2010-07-01

235

ROS1-rearranged lung cancer: a clinicopathologic and molecular study of 15 surgical cases.  

UK PubMed Central (United Kingdom)

Recent discovery of ROS1 gene fusion in a subset of lung cancers has raised clinical interest, because ROS1 fusion-positive cancers are reportedly sensitive to kinase inhibitors. To better understand these tumors, we examined 799 surgically resected non-small cell lung cancers by reverse transcriptase polymerase chain reaction and identified 15 tumors harboring ROS1 fusion transcripts (2.5% of adenocarcinomas). The most frequent fusion partner was CD74 followed by EZR. The affected patients were often younger nonsmoking female individuals, and they had overall survival rates similar to those of the ROS1 fusion-negative cancer patients. All the ROS1 fusion-positive tumors were adenocarcinomas except 1, which was an adenosquamous carcinoma. Histologic examination identified an at least focal presence of either solid growth with signet-ring cells or cribriform architecture with abundant extracellular mucus in 53% of the cases. These 2 patterns are reportedly also characteristic of anaplastic lymphoma kinase (ALK)-rearranged lung cancers, and our data suggest a phenotypic resemblance between the ROS1-rearranged and ALK-rearranged tumors. All tumors except 1 were immunoreactive to thyroid transcription factor-1. Fluorescence in situ hybridization using ROS1 break-apart probes revealed positive rearrangement signals in 23% to 93% of the tumor cells in ROS1 fusion-positive cancers, which were readily distinguished using a 15% cutoff value from 50 ROS1 fusion-negative tumors tested, which showed 0% to 6% rearrangement signals. However, this perfect test performance was achieved only when isolated 3' signals were included along with classic split signals in the definition of rearrangement positivity. Fluorescence in situ hybridization signal patterns were unrelated to 5' fusion partner genes. All ROS1 fusion-positive tumors lacked alteration of EGFR, KRAS, HER2, ALK, and RET genes.

Yoshida A; Kohno T; Tsuta K; Wakai S; Arai Y; Shimada Y; Asamura H; Furuta K; Shibata T; Tsuda H

2013-04-01

236

ROS1-rearranged lung cancer: a clinicopathologic and molecular study of 15 surgical cases.  

Science.gov (United States)

Recent discovery of ROS1 gene fusion in a subset of lung cancers has raised clinical interest, because ROS1 fusion-positive cancers are reportedly sensitive to kinase inhibitors. To better understand these tumors, we examined 799 surgically resected non-small cell lung cancers by reverse transcriptase polymerase chain reaction and identified 15 tumors harboring ROS1 fusion transcripts (2.5% of adenocarcinomas). The most frequent fusion partner was CD74 followed by EZR. The affected patients were often younger nonsmoking female individuals, and they had overall survival rates similar to those of the ROS1 fusion-negative cancer patients. All the ROS1 fusion-positive tumors were adenocarcinomas except 1, which was an adenosquamous carcinoma. Histologic examination identified an at least focal presence of either solid growth with signet-ring cells or cribriform architecture with abundant extracellular mucus in 53% of the cases. These 2 patterns are reportedly also characteristic of anaplastic lymphoma kinase (ALK)-rearranged lung cancers, and our data suggest a phenotypic resemblance between the ROS1-rearranged and ALK-rearranged tumors. All tumors except 1 were immunoreactive to thyroid transcription factor-1. Fluorescence in situ hybridization using ROS1 break-apart probes revealed positive rearrangement signals in 23% to 93% of the tumor cells in ROS1 fusion-positive cancers, which were readily distinguished using a 15% cutoff value from 50 ROS1 fusion-negative tumors tested, which showed 0% to 6% rearrangement signals. However, this perfect test performance was achieved only when isolated 3' signals were included along with classic split signals in the definition of rearrangement positivity. Fluorescence in situ hybridization signal patterns were unrelated to 5' fusion partner genes. All ROS1 fusion-positive tumors lacked alteration of EGFR, KRAS, HER2, ALK, and RET genes. PMID:23426121

Yoshida, Akihiko; Kohno, Takashi; Tsuta, Koji; Wakai, Susumu; Arai, Yasuhito; Shimada, Yoko; Asamura, Hisao; Furuta, Koh; Shibata, Tatsuhiro; Tsuda, Hitoshi

2013-04-01

237

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

Directory of Open Access Journals (Sweden)

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.

Shih Ruey-Horng; Cheng Shin-Ei; Hsiao Li-Der; Kou Yu; Yang Chuen-Mao

2011-01-01

238

Condurango-glycoside-A fraction of Gonolobus condurango induces DNA damage associated senescence and apoptosis via ROS-dependent p53 signalling pathway in HeLa cells.  

UK PubMed Central (United Kingdom)

Gonolobus condurango plant extract is used as an anticancer drug in some traditional systems of medicine including homeopathy, but it apparently lacks any scientific validation. Further, no detailed study is available to suggest whether condurango-glycoside-A (CGA), a major ingredient of condurango serves as a potent anticancer compound. Therefore, we investigated apoptosis-inducing ability of CGA against cervix carcinoma cells (HeLa). ?-galactosidase-activity and DNA damage were critically studied at different time points; while induced DNA-damage was observed at 9-12th hours, senescence of cells appeared at a later stage (18th hour after CGA treatment), implicating thereby a possible role of DNA damage in inducing pre-mature cell senescence. Concurrently, the number of cells undergoing apoptosis increased along with increase in reactive oxygen species (ROS) generation. Expression of p53 was also up-regulated, indicating that apoptosis could have been mediated through p53 pathway. DCHFDA (4',6-Diamidino-2-phenylindole dihydrochloride) assay, acridine orange/ethidium bromide staining and annexin V/PI assay results collectively confirmed that apoptosis was induced by increased ROS generation. Reduction in proliferation of cells was further evidenced by the cell cycle arrest at G0/G1 stage. Expression profiles of certain relevant genes and proteins like p53, Akt, Bcl-2, Bax, cytochrome c and caspase 3 also provided evidence of ROS mediated p53 up-regulation and further boost in Bax expression and followed by cytochrome c release and activation of caspase 3. Overall results suggest that CGA initiates ROS generation, promoting up-regulation of p53 expression, thus resulting in apoptosis and pre-mature senescence associated with DNA damage.

Bishayee K; Paul A; Ghosh S; Sikdar S; Mukherjee A; Biswas R; Boujedaini N; Khuda-Bukhsh AR

2013-10-01

239

Condurango-glycoside-A fraction of Gonolobus condurango induces DNA damage associated senescence and apoptosis via ROS-dependent p53 signalling pathway in HeLa cells.  

Science.gov (United States)

Gonolobus condurango plant extract is used as an anticancer drug in some traditional systems of medicine including homeopathy, but it apparently lacks any scientific validation. Further, no detailed study is available to suggest whether condurango-glycoside-A (CGA), a major ingredient of condurango serves as a potent anticancer compound. Therefore, we investigated apoptosis-inducing ability of CGA against cervix carcinoma cells (HeLa). ?-galactosidase-activity and DNA damage were critically studied at different time points; while induced DNA-damage was observed at 9-12th hours, senescence of cells appeared at a later stage (18th hour after CGA treatment), implicating thereby a possible role of DNA damage in inducing pre-mature cell senescence. Concurrently, the number of cells undergoing apoptosis increased along with increase in reactive oxygen species (ROS) generation. Expression of p53 was also up-regulated, indicating that apoptosis could have been mediated through p53 pathway. DCHFDA (4',6-Diamidino-2-phenylindole dihydrochloride) assay, acridine orange/ethidium bromide staining and annexin V/PI assay results collectively confirmed that apoptosis was induced by increased ROS generation. Reduction in proliferation of cells was further evidenced by the cell cycle arrest at G0/G1 stage. Expression profiles of certain relevant genes and proteins like p53, Akt, Bcl-2, Bax, cytochrome c and caspase 3 also provided evidence of ROS mediated p53 up-regulation and further boost in Bax expression and followed by cytochrome c release and activation of caspase 3. Overall results suggest that CGA initiates ROS generation, promoting up-regulation of p53 expression, thus resulting in apoptosis and pre-mature senescence associated with DNA damage. PMID:23807740

Bishayee, Kausik; Paul, Avijit; Ghosh, Samrat; Sikdar, Sourav; Mukherjee, Avinaba; Biswas, Raktim; Boujedaini, N; Khuda-Bukhsh, Anisur Rahman

2013-06-27

240

Plumbagin treatment leads to apoptosis in human K562 leukemia cells through increased ROS and elevated TRAIL receptor expression.  

Science.gov (United States)

This study examined the ability of plumbagin to induce apoptosis in chronic myelogenous leukemia (CML). Plumbagin exposure led to a significant reduction in cell viability and the induction of apoptosis. Mechanistically, plumbagin treatment led to elevated levels of ROS. Plumbagin-induced apoptosis was inhibited by N-acetyl L-cysteine (NAC) and PEG-catalase. Furthermore, plumbagin exposure led to elevated expression of DR4 and DR5 and increased killing through soluble TRAIL. The plumbagin-induced increase in DR4 and DR5 was inhibited by treatment with NAC. Together, this study suggests that plumbagin may be an effective treatment of CML through increased sensitivity to TRAIL-mediated killing. PMID:21741707

Sun, Jingping; McKallip, Robert J

2011-07-08

 
 
 
 
241

Plumbagin treatment leads to apoptosis in human K562 leukemia cells through increased ROS and elevated TRAIL receptor expression.  

UK PubMed Central (United Kingdom)

This study examined the ability of plumbagin to induce apoptosis in chronic myelogenous leukemia (CML). Plumbagin exposure led to a significant reduction in cell viability and the induction of apoptosis. Mechanistically, plumbagin treatment led to elevated levels of ROS. Plumbagin-induced apoptosis was inhibited by N-acetyl L-cysteine (NAC) and PEG-catalase. Furthermore, plumbagin exposure led to elevated expression of DR4 and DR5 and increased killing through soluble TRAIL. The plumbagin-induced increase in DR4 and DR5 was inhibited by treatment with NAC. Together, this study suggests that plumbagin may be an effective treatment of CML through increased sensitivity to TRAIL-mediated killing.

Sun J; McKallip RJ

2011-10-01

242

Development of an in vitro skin sensitization test based on ROS production in THP-1 cells.  

Science.gov (United States)

Recently, it has been reported that reactive oxygen species (ROS) produced by contact allergens can affect dendritic cell migration and contact hypersensitivity. The aim of the present study was to develop a new in vitro assay that could predict the skin sensitizing potential of chemicals by measuring ROS production in THP-1 (human monocytic leukemia cell line) cells. THP-1 cells were pre-loaded with a ROS sensitive fluorescent dye, 5-(and 6-)-chloromethyl-2', 7'-dichlorodihydrofluorescein diacetate, acetyl ester (CM-H2DCFDA), for 15min, then incubated with test chemicals for 30min. The fluorescence intensity was measured by flow cytometry. For the skin sensitizers, 25 out of 30 induced over a 2-fold ROS production at more than 90% of cell viability. In contrast, increases were only seen in 4 out of 20 non-sensitizers. The overall accuracy for the local lymph node assay (LLNA) was 82% for 50 chemicals tested. A correlation was found between the estimated concentration showing 2-fold ROS production in the ROS assay and the EC3 values (estimated concentration required to induce positive response) of the LLNA. These results indicated that the THP-1 cell-based ROS assay was a rapid and highly sensitive detection system able to predict skin sensitizing potentials and potency of chemicals. PMID:23287046

Saito, Kazutoshi; Miyazawa, Masaaki; Nukada, Yuko; Sakaguchi, Hitoshi; Nishiyama, Naohiro

2012-12-31

243

Development of an in vitro skin sensitization test based on ROS production in THP-1 cells.  

UK PubMed Central (United Kingdom)

Recently, it has been reported that reactive oxygen species (ROS) produced by contact allergens can affect dendritic cell migration and contact hypersensitivity. The aim of the present study was to develop a new in vitro assay that could predict the skin sensitizing potential of chemicals by measuring ROS production in THP-1 (human monocytic leukemia cell line) cells. THP-1 cells were pre-loaded with a ROS sensitive fluorescent dye, 5-(and 6-)-chloromethyl-2', 7'-dichlorodihydrofluorescein diacetate, acetyl ester (CM-H2DCFDA), for 15min, then incubated with test chemicals for 30min. The fluorescence intensity was measured by flow cytometry. For the skin sensitizers, 25 out of 30 induced over a 2-fold ROS production at more than 90% of cell viability. In contrast, increases were only seen in 4 out of 20 non-sensitizers. The overall accuracy for the local lymph node assay (LLNA) was 82% for 50 chemicals tested. A correlation was found between the estimated concentration showing 2-fold ROS production in the ROS assay and the EC3 values (estimated concentration required to induce positive response) of the LLNA. These results indicated that the THP-1 cell-based ROS assay was a rapid and highly sensitive detection system able to predict skin sensitizing potentials and potency of chemicals.

Saito K; Miyazawa M; Nukada Y; Sakaguchi H; Nishiyama N

2013-03-01

244

Novel targets in non-small cell lung cancer: ROS1 and RET fusions.  

UK PubMed Central (United Kingdom)

The discovery of chromosomal rearrangements involving the anaplastic lymphoma kinase (ALK) gene in non-small cell lung cancer (NSCLC) has stimulated renewed interest in oncogenic fusions as potential therapeutic targets. Recently, genetic alterations in ROS1 and RET were identified in patients with NSCLC. Like ALK, genetic alterations in ROS1 and RET involve chromosomal rearrangements that result in the formation of chimeric fusion kinases capable of oncogenic transformation. Notably, ROS1 and RET rearrangements are rarely found with other genetic alterations, such as EGFR, KRAS, or ALK. This finding suggests that both ROS1 and RET are independent oncogenic drivers that may be viable therapeutic targets. In initial screening studies, ROS1 and RET rearrangements were identified at similar frequencies (approximately 1%-2%), using a variety of genotyping techniques. Importantly, patients with either ROS1 or RET rearrangements appear to have unique clinical and pathologic features that may facilitate identification and enrichment strategies. These features may in turn expedite enrollment in clinical trials evaluating genotype-directed therapies in these rare patient populations. In this review, we summarize the molecular biology, clinical features, detection, and targeting of ROS1 and RET rearrangements in NSCLC.

Gainor JF; Shaw AT

2013-01-01

245

ROS generation and multiple forms of mammalian mitochondrial glycerol-3-phosphate dehydrogenase.  

UK PubMed Central (United Kingdom)

Overproduction of reactive oxygen species (ROS) has been implicated in a range of pathologies. Mitochondrial flavin dehydrogenases glycerol-3-phosphate dehydrogenase (mGPDH) and succinate dehydrogenase (SDH) represent important ROS source, but the mechanism of electron leak is still poorly understood. To investigate the ROS production by the isolated dehydrogenases, we used brown adipose tissue mitochondria solubilized by digitonin as a model. Enzyme activity measurements and hydrogen peroxide production studies by Amplex Red fluorescence, and luminol luminescence in combination with oxygraphy revealed flavin as the most likely source of electron leak in SDH under in vivo conditions, while we propose coenzyme Q as the site of ROS production in the case of mGPDH. Distinct mechanism of ROS production by the two dehydrogenases is also apparent from induction of ROS generation by ferricyanide which is unique for mGPDH. Furthermore, using native electrophoretic systems, we demonstrated that mGPDH associates into homooligomers as well as high molecular weight supercomplexes, which represent native forms of mGPDH in the membrane. By this approach, we also directly demonstrated that isolated mGPDH itself as well as its supramolecular assemblies are all capable of ROS production.

Mrá?ek T; Holzerová E; Drahota Z; Ková?ová N; Vrbacký M; Ješina P; Houšt?k J

2013-08-01

246

X-ROS signalling is enhanced and graded by cyclic cardiomyocyte stretch.  

UK PubMed Central (United Kingdom)

AIMS: A sustained, single stretch of a cardiomyocyte activates a transient production of reactive oxygen species by membrane-located NADPH oxidase 2 (Nox2). This NoX2-dependent ROS (X-ROS) tunes cardiac Ca(2+) signalling by reversibly sensitizing sarcoplasmic reticulum Ca(2+) release channels. In contrast to static length changes, working heart cells are cyclically stretched and shortened in the living animal. Additionally, this stretch cycle is constantly varied by changes in the pre-load and heart rate. Thus, the objective of this study was (i) to characterize X-ROS signalling during stretch-shortening cycles and (ii) to evaluate how the amplitude (pre-load) and frequency (heart rate) of cell stretch affects X-ROS and Ca(2+) signalling. METHODS AND RESULTS: Single adult rat cardiomyocytes were attached to MyoTak™-coated micro-rods and stretched, while ROS production and Ca(2+) signals were monitored optically. Although a sustained stretch led to only a transient burst of ROS, cyclic stretch-shortening cycles led to a steady-state elevation of ROS production. Importantly, this new redox state was graded by both the amplitude of stretch (3-15%) and cycle frequency (1-4 Hz). Elevated ROS production enhanced Ca(2+) signalling sensitivity as measured by the Ca(2+) spark rate. CONCLUSION: The steady-state level of ROS production in a cardiomyocyte is graded by the amplitude and frequency of cell stretch. Thus, mechanical changes that depend on the pre-load and heart rate regulate a dynamic redox balance that tunes cellular Ca(2+) signalling.

Prosser BL; Ward CW; Lederer WJ

2013-05-01

247

ROS Induce Antiviral Innate Immune Response through Interferon-? Regulation in Human Nasal Epithelial Cells.  

UK PubMed Central (United Kingdom)

The goals of this study were to explore the role of interferon (IFN)-related innate immune response (IFN-ß, IFN-?) and reactive oxygen species (ROS) after influenza A virus (IAV) infection for antiviral innate immune activity in normal human nasal epithelial (NHNE) cells that are highly exposed to IAV. Passage-2 NHNE cells were inoculated with the IAV WSN/33 for 1, 2, and 3 days to assess the capacity of IFN and the relationship between ROS-generation and IFN-? secretion, for controlling IAV infection. Viral titer and IAV mRNA level increased after infection. In concert with viral titer, we found that generation of IFNs, such as IFN-ß, IFN-?1 and IFN-?2/3 was induced after IAV infection until three days post of infection (PI). Induction of IFN-?-gene expression and protein secretion might be predominant after IAV infection. Similarly, we observed that intracellular ROS generation increased 60 minutes after IAV infection. Viral titer and mRNA level of IAV were significantly higher in cases with scavenging ROS, in cases with an induced IFN-? mRNA level or where secreted protein concentration of IFN-? was attenuated after suppression of ROS generation. Both mitochondrial and Duox2-generated ROS were correlated with IAV mRNA and viral titer. Inhibition of mitochondrial ROS generation and knock-down of Duox2 gene expression highly increased IAV viral titer and decreased IFN-? secretion. Our findings suggest that production of ROS might be responsible for IFN-? secretion to control IAV infection. Both mitochondria and Duox2 are possible sources of ROS generation, which is required to initiate an innate immune response in NHNE cells.

Kim HJ; Kim CH; Ryu JH; Kim MJ; Park CY; Lee JM; Holtzman MJ; Yoon JH

2013-06-01

248

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

UK PubMed Central (United Kingdom)

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.

Yang CM; Lee IT; Hsu RC; Chi PL; Hsiao LD

2013-10-01

249

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

2013-06-14

250

Pu-erh black tea supplementation decreases quinocetone-induced ROS generation and oxidative DNA damage in Balb/c mice.  

Science.gov (United States)

Quinocetone (3-methyl-2-quinoxalinbenzenevinylketo-1,4-dioxide, QCT), a new feed antibacterial agent of quinoxaline-1,4-dioxides family, has been used as an animal growth promoter. However, few data about its potential toxicity in vivo were available. In this study, genotoxicity of QCT and the relationship with oxidative stress were investigated. Balb/c mice with both sexes were administrated with QCT (12000, 6000 and 3000 mg/kg/bw, respectively) by gavage acutely. DNA damage, generation of reactive oxygen species (ROS) and activity of antioxidative system (total antioxidative capacity, glutathione, glutathione peroxidase, superoxide dismutase and catalase) in liver and kidney were determined. Moreover, Pu-erh black tea extract (BTE) was co-administrated with QCT to evaluate its protective effect against QCT-induced genotoxicity. The DNA damage was observed in all the groups treated with single QCT except the liver with dose of 3000 mg/kg/bw. ROS was accumulated and antioxidative system was suppressed both in liver and kidney. However, the DNA damage, as well as the ROS, was decreased, while the activity of antioxidative system was increased in mice after co-administration of QCT and BTE. These data demonstrate that oxidative stress mediated the genotoxicity induced by QCT in vivo. Furthermore, this oxidative DNA damage can be attenuated by pre-supplementation of BTE. PMID:21112366

Wang, Di; Zhong, Ying; Luo, Xiao; Wu, Shuang; Xiao, Rong; Bao, Wei; Yang, Wei; Yan, Hong; Yao, Ping; Liu, Liegang

2010-11-26

251

Cytotoxicity and mechanism of action of a new ROS-generating microsphere formulation for circumventing multidrug resistance in breast cancer cells.  

Science.gov (United States)

Multidrug resistance (MDR) is one of the main challenges in the treatment of breast cancer. A new microsphere formulation able to generate reactive oxygen species (ROS) locally was thus investigated for circumventing MDR in breast cancer cells in this work. Glucose oxidase (GOX) was encapsulated in alginate/chitosan hydrogel microspheres (ACMS-GOX). The in vitro cytotoxicity of ACMS-GOX to murine breast cancer EMT6/AR1.0 cells, which overexpress P-glycoprotein (P-gp), was evaluated by a clonogenic assay. The mechanism of the cytotoxicity of ACMS-GOX was investigated by using various extracellular and intracellular ROS scavengers and antioxidant enzyme inhibitors. The effect of lipid peroxidation and cellular uptake of GOX was also evaluated. ACMS-GOX exhibited similar dose and time-dependent cytotoxicity to EMT6/AR1.0 cells as to their wild-type EMT6/WT parent cells, in effect circumventing the MDR phenotype of EMT6/AR1.0 cells. Extracellular H(2)O(2) and intracellular hydroxyl radical were found to play critical roles in the cytotoxicity of ACMS-GOX. Cellular uptake of GOX was negligible and thus not responsible for intracellular ROS generation. Combining ACMS-GOX with intracellular antioxidant inhibitors-enhanced cytoxicity. This work demonstrates that the ACMS-GOX are effective in circumventing P-gp-mediated MDR in breast cancer cells. PMID:19618264

Liu, Qun; Shuhendler, Adam; Cheng, Ji; Rauth, Andrew Michael; O'Brien, Peter; Wu, Xiao Yu

2009-07-18

252

ROS kinase fusions are not common in Chinese patients with cholangiocarcinoma.  

UK PubMed Central (United Kingdom)

OBJECTIVE: To investigate the expressions of different forms of ROS fusions in Chinese patients with cholangiocarcinoma (CCA). METHODS: RT-PCR was employed to examine formalin-fixed and paraffin-embedded CCA samples from stage I-IV patients for detection of ROS fusions involving Fused in Glioblastoma (FIG), solute carrier protein (SLC34A2) and major histocompatibility complex class II invariant chain (CD74). Serpin peptidase inhibitor clade A member 1 (SERPINA1) was detected as the reference gene. RESULTS: In all the 56 CCA samples, 80.4% (45/56) were positive for SERPINA1 expression as evaluable samples. Of these evaluable samples, none expressed the ROS fusions. CONCLUSION: ROS fusions are not common in Chinese CCA patients.

Liu P; Wu Y; Sun L; Zuo Q; Shi M

2013-04-01

253

Curcumin induces osteosarcoma MG63 cells apoptosis via ROS/Cyto-C/Caspase-3 pathway.  

UK PubMed Central (United Kingdom)

The antitumor effects of curcumin have attracted widespread attention worldwide. One of its major functions is to induce the apoptosis of tumor cells, but the antitumor mechanism is currently unclear. In the present study, we found that cell mortality and curcumin concentration were dose dependent. Curcumin of low concentrations (10 ??) could reduce the level of reactive oxygen species (ROS) in tumor cells, while curcumin of high concentrations (80 ??) was able to significantly increase the content of ROS. In addition, Western blotting detection suggested that curcumin of high concentrations can induce the release of Cyto-C and the activation of Caspase-3, and that ROS scavenger NAC apparently inhibits apoptosis protein release and activation, consequently slowing the curcumin-induced apoptosis. Taken together, curcumin further activates the mitochondrial apoptotic pathway by inducing cells to generate ROS and ultimately promotes the apoptosis of tumor cells.

Chang Z; Xing J; Yu X

2013-08-01

254

Sustained production of ROS triggers compensatory proliferation and is required for regeneration to proceed.  

UK PubMed Central (United Kingdom)

A major issue in regenerative medicine is the role of injury in promoting cell plasticity. Here we explore the function of reactive oxygen species (ROS) induced through lesions in adult zebrafish. We show that ROS production, following adult fin amputation, is tightly regulated in time and space for at least 24 hours, whereas ROS production remains transient (2 hours) in mere wound healing. In regenerative tissue, ROS signaling triggers two distinct parallel pathways: one pathway is responsible for apoptosis, and the other pathway is responsible for JNK activation. Both events are involved in the compensatory proliferation of stump epidermal cells and are necessary for the progression of regeneration. Both events impact the Wnt, SDF1 and IGF pathways, while apoptosis only impacts progenitor marker expression. These results implicate oxidative stress in regeneration and provide new insights into the differences between healing and regeneration.

Gauron C; Rampon C; Bouzaffour M; Ipendey E; Teillon J; Volovitch M; Vriz S

2013-01-01

255

A preliminary cyber-physical security assessment of the Robot Operating System (ROS)  

Science.gov (United States)

Over the course of the last few years, the Robot Operating System (ROS) has become a highly popular software framework for robotics research. ROS has a very active developer community and is widely used for robotics research in both academia and government labs. The prevalence and modularity of ROS cause many people to ask the question: "What prevents ROS from being used in commercial or government applications?" One of the main problems that is preventing this increased use of ROS in these applications is the question of characterizing its security (or lack thereof). In the summer of 2012, a crowd sourced cyber-physical security contest was launched at the cyber security conference DEF CON 20 to begin the process of characterizing the security of ROS. A small-scale, car-like robot was configured as a cyber-physical security "honeypot" running ROS. DEFFCON-20 attendees were invited to find exploits and vulnerabilities in the robot while network traffic was collected. The results of this experiment provided some interesting insights and opened up many security questions pertaining to deployed robotic systems. The Federal Aviation Administration is tasked with opening up the civil airspace to commercial drones by September 2015 and driverless cars are already legal for research purposes in a number of states. Given the integration of these robotic devices into our daily lives, the authors pose the following question: "What security exploits can a motivated person with little-to-no experience in cyber security execute, given the wide availability of free cyber security penetration testing tools such as Metasploit?" This research focuses on applying common, low-cost, low-overhead, cyber-attacks on a robot featuring ROS. This work documents the effectiveness of those attacks.

McClean, Jarrod; Stull, Christopher; Farrar, Charles; Mascareñas, David

2013-05-01

256

Bortezomib and SAHA synergistically induce ROS-driven caspase-dependent apoptosis of nasopharyngeal carcinoma and block replication of Epstein-Barr virus.  

UK PubMed Central (United Kingdom)

A novel drug combination of a proteasome inhibitor, bortezomib, and a histone deacetylase inhibitor, suberoylanilide hydroxamic acid (SAHA), was tested in nasopharyngeal carcinoma (NPC), both in vitro and in vivo. Dose-response of different concentrations of bortezomib and SAHA on inhibition of cell proliferation of NPC was determined. Mechanisms of apoptosis and effects on lytic cycle activation of Epstein-Barr virus (EBV) were investigated. Combination of bortezomib and SAHA (bortezomib/SAHA) synergistically induced killing of a panel of NPC cell lines. Pronounced increase in sub-G1, Annexin V-positive, and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL)-positive cell populations were detected after treatment with bortezomib/SAHA when compared with either drug alone. Concomitantly, markedly augmented proteolytic cleavage of PARP, caspase-3, -7, -8, and -9, reactive oxygen species (ROS) generation, and caspase-8-dependent histone acetylation were observed. ROS scavenger, N-acetyl cysteine, diminished the apoptotic effects of bortezomib/SAHA, whereas caspase inhibitor Z-VAD-FMK significantly suppressed the apoptosis without decreasing the generation of ROS. Bortezomib inhibited SAHA's induction of EBV replication and abrogated production of infectious viral particles in NPC cells. Furthermore, bortezomib/SAHA potently induced apoptosis and suppressed the growth of NPC xenografts in nude mice. In conclusion, the novel drug combination of bortezomib and SAHA is highly synergistic in the killing of NPC cells in vitro and in vivo. The major mechanism of cell death is ROS-driven caspase-dependent apoptosis. Bortezomib antagonizes SAHA's activation of EBV lytic cycle in NPC cells. This study provides a strong basis for clinical testing of the combination drug regimen in patients with NPC.

Hui KF; Lam BH; Ho DN; Tsao SW; Chiang AK

2013-05-01

257

Diallyl trisufide (DATS) suppresses high glucose-induced cardiomyocyte apoptosis by inhibiting JNK/NF?B signaling via attenuating ROS generation.  

UK PubMed Central (United Kingdom)

BACKGROUND: Hyperglycemia is an important risk factor for cardiovascular diseases no matter if it resulted from type I or type II diabetes mellitus. High glucose-induced generation of reactive oxygen species (ROS) can lead to diabetic cardiomyopathy. In our previous study, we showed that NADPH oxidase-related ROS-induced apoptosis is mediated via the JNK-dependent activation of NF-?B in cardiomyocytes exposed to high glucose (HG). OBJECTIVE: In this study, we investigated the mechanisms governing the anti-apoptotic effect of diallyl trisulfide (DATS) on HG-exposed cardiac cells both in vitro and in vivo. METHODS: H9c2 cells were incubated with media containing 5.5 or 33mM of glucose for 36h in the presence or absence of DATS. RESULTS: We found that DATS treatment led to a dose-dependent decrease in ROS levels as well as protein levels of p22phox, gp91phox, phosphorylated JNK, and phosphorylated c-Jun. In addition, DATS inhibited the HG-induced activation of caspase 3 as well as the nuclear translocation of NF-?B. Similar results were observed in HG-exposed neonatal primary cardiomyocytes and streptozotocin-treated diabetic rats. Echocardiographic data showed that DATS administration led to a marked increase in fractional shortening and cardiac output. CONCLUSION: DATS appears to suppress high glucose-induced cardiomyocyte apoptosis by inhibiting NADPH oxidase-related ROS and its downstream JNK/NF-?B signaling, and may possess the potential on the therapy of diabetic cardiomyopathy.

Kuo WW; Wang WJ; Tsai CY; Way CL; Hsu HH; Chen LM

2013-09-01

258

Modulation of NO and ROS production by AdiNOS transduced vascular cells through supplementation with L-Arg and BH4: Implications for gene therapy of restenosis.  

UK PubMed Central (United Kingdom)

OBJECTIVE: Gene therapy with viral vectors encoding for NOS enzymes has been recognized as a potential therapeutic approach for the prevention of restenosis. Optimal activity of iNOS is dependent on the intracellular availability of L-Arg and BH4 via prevention of NOS decoupling and subsequent ROS formation. Herein, we investigated the effects of separate and combined L-Arg and BH4 supplementation on the production of NO and ROS in cultured rat arterial smooth muscle and endothelial cells transduced with AdiNOS, and their impact on the antirestenotic effectiveness of AdiNOS delivery to balloon-injured rat carotid arteries. METHODS AND RESULTS: Supplementation of AdiNOS transduced endothelial and vascular smooth muscle cells with L-Arg (3.0 mM), BH4 (10 ?M) and especially their combination resulted in a significant increase in NO production as measured by nitrite formation in media. Formation of ROS was dose-dependently increased following transduction with increasing MOIs of AdiNOS. Exposure of RASMC to AdiNOS tethered to meshes via a hydrolyzable cross-linker, modeling viral delivery from stents, resulted in increased ROS production, which was decreased by supplementation with BH4 but not L-Arg or L-Arg/BH4. Enhanced cell death, caused by AdiNOS transduction, was also preventable with BH4 supplementation. In the rat carotid model of balloon injury, intraluminal delivery of AdiNOS in BH4-, L-Arg-, and especially in BH4 and L-Arg supplemented animals was found to significantly enhance the antirestenotic effects of AdiNOS-mediated gene therapy. CONCLUSIONS: Fine-tuning of iNOS function by L-Arg and BH4 supplementation in the transduced vasculature augments the therapeutic potential of gene therapy with iNOS for the prevention of restenosis.

Forbes SP; Alferiev IS; Chorny M; Adamo RF; Levy RJ; Fishbein I

2013-09-01

259

Iodine deficiency-induced long lasting angiogenic reaction in thyroid cancers occurs via a VEGF-HIF-1, but not a ROS dependent pathway.  

UK PubMed Central (United Kingdom)

Background: In the thyroid, iodine deficiency (ID) induces angiogenesis via a tightly controlled ROS-HIF-VEGF dependent pathway. Deficient iodine intake may be associated with increased thyroid cancer incidence. The hypothesis of this work is to test if ID affects angiogenic processes in thyroid malignant cells by altering the ROS-HIF-VEGF pathway. Methods: Goiters were obtained in RET/PTC3 transgenic and wild type (wt) mice and ID was induced in three thyroid carcinoma cell lines (TPC-1, 8305c, R082-w1). Thyroid blood flow, VEGF mRNA and protein, and HIF-1? protein expression were measured. The role of HIF-1 and of reactive oxygen species (ROS) was assessed using echinomycin and N-acetylcysteine (NAC), respectively. Results: The goitrogen treatment increased the thyroid blood flow in wt and RET/PTC3 mice. Compared to wt mice, basal VEGF expression was higher in RET/PTC3 mice and increased with the goitrogen treatment. In the three cell lines, ID induced a marked increase in VEGF mRNA and a moderate increase in HIF-1? protein expression which were not transient as in normal cells. ID-induced VEGF mRNA expression was fully (8305c), partially (TPC-1), or not (R082-w1) blocked by echinomycin. NAC had no effect on ID-induced VEGF mRNA and HIF-1? protein expression in the three cell lines. Conclusions: ID induces a long lasting angiogenic phenotype in thyroid cancer cells that occurs through VEGF induction via a pathway partially mediated by HIF-1, but not by ROS. These results suggest that, in contrast with normal cells, ID-induced angiogenesis in cancer cells occurs via alternative and likely less controlled routes, thereby leading to uncontrolled growth.

Gerard AC; Humblet K; Wilvers C; Poncin S; Derradji H; de Ville de Goyet C; Abou-El-Ardat K; Baatout S; Sonveaux P; Denef JF; Colin IM

2012-04-01

260

Reactive oxygen species (ROS) – a family of fate deciding molecules pivotal in constructive inflammation and wound healing  

Directory of Open Access Journals (Sweden)

Full Text Available Wound healing requires a fine balance between the positive and deleterious effects of reactive oxygen species (ROS); a group of extremely potent molecules, rate limiting in successful tissue regeneration. A balanced ROS response will debride and disinfect a tissue and stimulate healthy tissue turnover; suppressed ROS will result in infection and an elevation in ROS will destroy otherwise healthy stromal tissue. Understanding and anticipating the ROS niche within a tissue will greatly enhance the potential to exogenously augment and manipulate healing.Tissue engineering solutions to augment successful healing and remodelling of wounded or diseased tissue rely on a controlled balance between the constructive and destructive capacity of the leukocyte secretome, including ROS.This review comprehensively considers leukocyte derived ROS in tissue repair with particular interest in surgical intervention with inclusion of a biomaterial. The article considers ROS fundamental chemistry, formation, stimulation and clearance before applying this to discuss the implications of ROS in healing tissue with and without a biomaterial. We also systematically discuss ROS in leukocyte signalling and compare and contrast experimental means of measuring ROS.

N Bryan; H Ahswin; N Smart; Y Bayon; S Wohlert; JA Hunt

2012-01-01

 
 
 
 
261

Triiodothyronine (T3) does not induce Rankl expression in rat Ros 17/2.8 cells Triiodotironina (T3) não induz a expressão de Rankl em células de rato ROS 17/2.8  

Directory of Open Access Journals (Sweden)

Full Text Available Osteoclastogenesis may be regulated via activation of the RANK/RANKL (receptor activator of nuclear factor-kappa B/ receptor activator of nuclear factor-kappa B ligand) system, which is mediated by osteoblasts. However, the bone loss mechanism induced by T3 (triiodothyronine) is still controversial. In this study, osteoblastic lineage rat cells (ROS 17/2.8) were treated with T3 (10-8 M, 10-9 M, and 10-10 M), and RANKL mRNA (messenger RNA) expression was measured by semiquantitative RT-PCR. Our results show that T3 concentrations used did not significantly enhance RANKL expression compared to controls without hormone treatment. This data suggests that other mechanisms, unrelated to the RANK/RANKL system, might be to activate osteoclast differentiation in these cells.A osteoclastogênese pode ser regulada via ativação do sistema RANK/RANKL (receptor ativador do fator nuclear kapa B/ ligante do receptor do fator nuclear kapa B), que é mediado pelos osteoblastos. Entretanto, o mecanismo de perda óssea induzido pelo T3 (triiodotironina) ainda é controverso. Neste estudo, a linhagem osteoblástica de células de rato ROS 17/2.8 foi tratada com T3 (10-8 M, 10-9 M e 10-10 M), e a expressão do mRNA do RANKL foi medida por RT-PCR semiquantitativo. Nossos resultados mostraram que as concentrações de T3 utilizadas não induziram significativamente a expressão do RANKL, comparado ao controle (sem tratamento hormonal). Estes dados sugerem que outros mecanismos, não relacionados ao sistema RANK/RANKL, são usados para ativar a diferenciação osteoclástica nestas células.

Patrícia P. Saraiva; Silvania S. Teixeira; Célia Regina Nogueira; Carlos Roberto Padovani

2008-01-01

262

Triiodothyronine (T3) does not induce Rankl expression in rat Ros 17/2.8 cells/ Triiodotironina (T3) não induz a expressão de Rankl em células de rato ROS 17/2.8  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese A osteoclastogênese pode ser regulada via ativação do sistema RANK/RANKL (receptor ativador do fator nuclear kapa B/ ligante do receptor do fator nuclear kapa B), que é mediado pelos osteoblastos. Entretanto, o mecanismo de perda óssea induzido pelo T3 (triiodotironina) ainda é controverso. Neste estudo, a linhagem osteoblástica de células de rato ROS 17/2.8 foi tratada com T3 (10-8 M, 10-9 M e 10-10 M), e a expressão do mRNA do RANKL foi medida por RT-PCR semiqu (more) antitativo. Nossos resultados mostraram que as concentrações de T3 utilizadas não induziram significativamente a expressão do RANKL, comparado ao controle (sem tratamento hormonal). Estes dados sugerem que outros mecanismos, não relacionados ao sistema RANK/RANKL, são usados para ativar a diferenciação osteoclástica nestas células. Abstract in english Osteoclastogenesis may be regulated via activation of the RANK/RANKL (receptor activator of nuclear factor-kappa B/ receptor activator of nuclear factor-kappa B ligand) system, which is mediated by osteoblasts. However, the bone loss mechanism induced by T3 (triiodothyronine) is still controversial. In this study, osteoblastic lineage rat cells (ROS 17/2.8) were treated with T3 (10-8 M, 10-9 M, and 10-10 M), and RANKL mRNA (messenger RNA) expression was measured by semiqu (more) antitative RT-PCR. Our results show that T3 concentrations used did not significantly enhance RANKL expression compared to controls without hormone treatment. This data suggests that other mechanisms, unrelated to the RANK/RANKL system, might be to activate osteoclast differentiation in these cells.

Saraiva, Patrícia P.; Teixeira, Silvania S.; Nogueira, Célia Regina; Padovani, Carlos Roberto

2008-02-01

263

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

2013-08-26

264

Superoxide-mediated protection of Escherichia coli from antimicrobials.  

UK PubMed Central (United Kingdom)

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.

Mosel M; Li L; Drlica K; Zhao X

2013-08-01

265

Superoxide-Mediated Protection of Escherichia coli from Antimicrobials.  

UK PubMed Central (United Kingdom)

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.

Mosel M; Li L; Drlica K; Zhao X

2013-11-01

266

Nitric oxide contributes to copper tolerance by influencing ROS metabolism in Arabidopsis.  

UK PubMed Central (United Kingdom)

KEY MESSAGE: Nitric oxide improves copper tolerance via modulation of superoxide and hydrogen peroxide levels. This reflects the necessity of a well-coordinated interplay between NO and ROS during stress tolerance. Copper (Cu) excess causes toxicity and one probable consequence of this is the disturbance of cell redox state maintenance, inter alia, by reactive oxygen- (ROS) and nitrogen species (RNS). The objective of this paper was to examine the role of nitric oxide (NO) in Cu stress tolerance and its relationship with ROS in Arabidopsis. In agar-grown seedlings, concentration-dependent Cu accumulation was observed. The 5 ?M Cu resulted in reduced cell viability in the NO overproducing nox1 and gsnor1-3 root tips compared to the wild-type (WT). In contrast, 25 and 50 ?M Cu caused higher viability in these mutants, while in the NO-lacking nia1nia2 lower viability was detected than in the WT. The exogenous NO donor enhanced cell viability and scavenging endogenous NO decreased it in Cu-exposed WT seedlings. Besides, SNP in nia1nia2 roots led to the improvement of viability. The ascorbic acid-deficient mutants (vtc2-1, vtc2-3) possessing slightly elevated ROS levels proved to be Cu sensitive, while miox4 showing decreased ROS production was more tolerant to Cu than the WT. In nox1 and gsnor1-3, Cu did not induce superoxide formation, and H2O2 accumulation occurred only in the case of NO deficiency. Based on these, under mild stress NO intensifies cell injury, while in the case of severe Cu excess it contributes to better viability. ROS were found to be responsible for aggravation of Cu-induced damage. NO alleviates acute Cu stress via modulation of O 2 (·-) and H2O2 levels reflecting the necessity of a well-coordinated interplay between NO and ROS during stress tolerance.

Pet? A; Lehotai N; Feigl G; Tugyi N; Ordög A; Gémes K; Tari I; Erdei L; Kolbert Z

2013-09-01

267

Saxifragifolin D induces the interplay between apoptosis and autophagy in breast cancer cells through ROS-dependent endoplasmic reticulum stress.  

UK PubMed Central (United Kingdom)

Breast cancer is the leading cause of cancer death among females, and novel chemotherapeutic drugs for treating breast cancer are needed urgently. Saxifragifolin D (SD) was isolated by our group from Androsace umbellata which is commonly used to treat solid tumor. In this study, we evaluated its growth inhibitory effect on breast cancer cells and explored the underlying molecular mechanisms. Our results showed that SD inhibited the growth of both MCF-7 and MDA-MB-231 cells significantly. Mechanistic studies demonstrated that SD induced apoptosis through mitochondrial apoptotic pathway. Evidence of SD-induced autophagy included the occurrence of autophagic vacuoles, up-regulation of LC3-II, Beclin1 and Vps34. Inhibition of autophagy by bafilomycin A1 or Beclin1 siRNA pretreatment decreased the ratio of apoptosis, indicating that autophagy induction contributes to apoptosis and is required for the latter. SD was also found to induce endoplasmic reticulum stress, accompanied by ROS production, increase of intracellular calcium and up-regulation of Bip, IRE1? and XBP-1s. Inhibition of endoplasmic reticulum stress by N-acetyl-l-cysteine, tauroursodeoxycholic acid or IRE1? siRNA pretreatment could suppress both apoptosis and autophagy. Besides, increases in CHOP, calnexin, calpain, p-JNK and p-Bcl-2 were followed by subsequent dissociation of Beclin1 from Bcl-2, further suggesting endoplasmic reticulum stress to be the common signaling pathway shared by SD-induced apoptosis and autophagy. In conclusion, SD inhibits breast cancer cell growth and induces interplay between apoptosis and autophagy through ROS-mediated endoplasmic reticulum stress. It will provide molecular bases for developing SD into a drug candidate for the treatment of breast cancer.

Shi JM; Bai LL; Zhang DM; Yiu A; Yin ZQ; Han WL; Liu JS; Li Y; Fu DY; Ye WC

2013-04-01

268

Abarema cochliacarpos reduces LPS-induced inflammatory response in murine peritoneal macrophages regulating ROS-MAPK signal pathway.  

UK PubMed Central (United Kingdom)

ETHNOPHARMACOLOGICAL RELEVANCE: Abarema cochliacarpos (Gomes) Barneby and Grimes (Fabaceae), known by the vulgar name of Babatenã, has been traditionally used in Northeast Brazil, as an anti-inflammatory remedy. Previous studies have demonstrated its anti-inflammatory and antiulcer effects in skin lesion, alcohol gastric ulcer and acute and chronic colitis. AIMS: The present study was designed to evaluate the antioxidant and anti-inflammatory effects of the butanolic fraction from A. cochliacarpos (BFAC) and its major flavonoid, (+)-catechin, in LPS-stimulated murine peritoneal macrophages. Moreover, we studied the role of mitogen-activated protein kinase (MAPK)s and NF-kB signaling pathways possibly involved in the beneficial effects. MATERIALS AND METHODS: The quantification of the extract was carried out by ultra-performance liquid chromatography analysis. Cell viability was determined using SRB assay. Nitric oxide (NO) production was analyzed by Griess method and intracellular reactive oxygen species (ROS) by fluorescence analysis. In addition, cyclooxygenase (COX-2) and inducible nitric oxide synthase (iNOS) expression, MAPK activation and IkappaBalpha (IKB?) degradation, were determined by Western blot. RESULTS: After BFAC characterization, (+)-catechin was revealed as its major constituent. Both BFAC and (+)-catechin, exerted significant anti-oxidant and anti-inflammatory effects inhibiting LPS-induced intracellular ROS and NO production in peritoneal macrophages. Additionally, the extract but also its major component reduced pro-inflammatory proteins expression probably through c-Jun N-terminal kinase and p38 MAPK signaling pathways. CONCLUSION: These data suggest that the beneficial effects of BFAC might be mediated, at least in part, by the presence of (+)-catechin. Conclusively our findings confirm the potential of A. cochliacarpos as a new therapeutic strategy for the management of inflammatory and oxidative stress-related diseases.

Sánchez-Fidalgo S; da Silva MS; Cárdeno A; Aparicio-Soto M; Salvador MJ; Frankland Sawaya AC; Souza-Brito AR; de la Lastra CA

2013-08-01

269

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

UK PubMed Central (United Kingdom)

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.

Lee IT; Lin CC; Lee CY; Hsieh PW; Yang CM

2013-01-01

270

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

271

High dietary intake of sodium selenite induces oxidative DNA damage in rat liver.  

Science.gov (United States)

One mechanism for the cancer-chemopreventive effects of high selenium (Se) intake is hypothesized to be antioxidant protection of DNA. In this work we examine DNA oxidation in whole animals as a function of dietary Se intake and carcinogen administration. Weanling male Sprague-Dawley rats were fed a basal, Torula yeast-based, Se-deficient diet supplemented with 0, 0.15, or 2.0 ppm Se as sodium selenite for 10 wk. They were then injected with 0, 0.1, or 10 mg /kg body weight of the pro-oxidant carcinogen N-nitrosodiethylamine. High levels of carcinogen and high levels of selenite intake each increased concentration of 8-hydroxy-2'-deoxyguanosine in liver DNA. Se-dependent glutathione peroxidase I gene expression and enzyme activity were dramatically reduced by dietary Se deficiency but were unaffected by carcinogen administration. There were no significant main or interactive effects of Se or carcinogen on activity or gene expression of the DNA repair enzyme 8-oxoguanine glycosylase I. These results do not support the hypothesis that high Se intake may be cancer-preventive by inhibiting oxidative DNA damage. Rather than inhibiting oxidative DNA damage, these findings suggest that high dietary intake of inorganic Se may promote in vivo DNA oxidation. PMID:15203381

Wycherly, Benjamin J; Moak, Michael A; Christensen, Merrill J

2004-01-01

272

DNA damage, repair, and replication in selenite-induced cataract in rat lens.  

UK PubMed Central (United Kingdom)

DNA synthesis was evaluated in vitro by measuring incorporation of 3H-thymidine in rat lens following systemic delivery of a cataractogenic dose of selenite. Among early metabolic changes observed in the lenses of rats receiving a single dose of 30 nmol Na2SeO3/g body weight was a 30% decrease in DNA replication in lens epithelium occurring between 6 and 12 h after administration of the selenite. This change was followed by an 80% increase in replication by 24 h. Thymidine incorporation in DNA remained elevated compared to controls through 96 h. Unscheduled DNA synthesis was found to be approximately 10% of the total DNA formed, but there was a 30% and 70% increase of this putative DNA repair in the lenses from selenite-treated animals at 6 and 24 h after the injection. Using the alkaline unwinding assay, the proportion of single-strand DNA in lenses from selenite-treated animals increased after 24 h. This estimate of DNA damage was greater in lenses after 96 h. Each component of DNA metabolism: damage, repair, and replication, was affected by the occurrence of selenite stress in lens. These changes both preceded and accompanied nuclear cataract formation.

Huang LL; Hess JL; Bunce GE

1990-11-01

273

DNA damage, repair, and replication in selenite-induced cataract in rat lens.  

Science.gov (United States)

DNA synthesis was evaluated in vitro by measuring incorporation of 3H-thymidine in rat lens following systemic delivery of a cataractogenic dose of selenite. Among early metabolic changes observed in the lenses of rats receiving a single dose of 30 nmol Na2SeO3/g body weight was a 30% decrease in DNA replication in lens epithelium occurring between 6 and 12 h after administration of the selenite. This change was followed by an 80% increase in replication by 24 h. Thymidine incorporation in DNA remained elevated compared to controls through 96 h. Unscheduled DNA synthesis was found to be approximately 10% of the total DNA formed, but there was a 30% and 70% increase of this putative DNA repair in the lenses from selenite-treated animals at 6 and 24 h after the injection. Using the alkaline unwinding assay, the proportion of single-strand DNA in lenses from selenite-treated animals increased after 24 h. This estimate of DNA damage was greater in lenses after 96 h. Each component of DNA metabolism: damage, repair, and replication, was affected by the occurrence of selenite stress in lens. These changes both preceded and accompanied nuclear cataract formation. PMID:2095318

Huang, L L; Hess, J L; Bunce, G E

1990-11-01

274

Heterologous transmembrane signaling by a human insulin receptor-v-ros hybrid in Chinese hamster ovary cells  

Energy Technology Data Exchange (ETDEWEB)

A hybrid receptor molecule composed of the extracellular ligand-binding domain of the human insulin receptor and the transmembrane and cytoplasmic (protein-tyrosine kinase) domains of the chicken sarcoma virus UR2 transforming protein p68/sup gag-ros/ has been constructed and expressed in Chinese hamster ovary (CHO) cells. The hybrid is processed normally into ..cap alpha.. and hybrid ..beta.. subunits, is expressed on the cell surface at high levels, and binds insulin with near-wild-type affinity. Furthermore, insulin stimulates the phosphorylation on tyrosine resides of the hybrid ..beta..-subunit in vivo and the phosphorylation of an exogeneous substrate (poly(Glu,Tyr)) in vitro. Thus the hybrid is capable of heterologous transmembrane signaling. However, the hybrid mediates neither the insulin-activated uptake of 2-deoxyglucose nor the incorporation of (/sup 3/H)thymidine into DNA, suggesting that the physiological response(s) mediated by ligand-activated protein-tyrosine kinases may utilize distinct intracellular mechanisms for postreceptor signaling

Ellis, L.; Morgan, D.O.; Jong, S.M.; Wang, L.H.; Roth, R.A.; Rutter, W.J.

1987-08-01

275

Mucuna pruriens and its major constituent L-DOPA recover spermatogenic loss by combating ROS, loss of mitochondrial membrane potential and apoptosis.  

UK PubMed Central (United Kingdom)

BACKGROUND: The Ayurvedic medicinal system claims Mucuna pruriens (MP) to possess pro-male fertility, aphrodisiac and adaptogenic properties. Some scientific evidence also supports its pro-male fertility properties; however, the mechanism of its action is not yet clear. The present study aimed at demonstrating spermatogenic restorative efficacy of MP and its major constituent L-DOPA (LD), and finding the possible mechanism of action thereof in a rat model. METHODOLOGY/FINDINGS: Ethinyl estradiol (EE) was administered at a rate of 3 mg/kg body weight (BW)/day for a period of 14 days to generate a rat model with compromised spermatogenesis. MP and LD were administered in two separate groups of these animals starting 15(th) day for a period of 56 days, and the results were compared with an auto-recovery (AR) group. Sperm count and motility, testis histo-architecture, level of reactive oxygen species (ROS), mitochondrial membrane potential (MMP), apoptosis, peripheral hormone levels and testicular germ cell populations were analysed, in all experimental groups. We observed efficient and quick recovery of spermatogenesis in MP and LD groups in comparison to the auto-recovery group. The treatment regulated ROS level, apoptosis, and mitochondrial membrane potential (MMP), recovered the hypothalamic-pituitary-gonadal axis and the number of testicular germ cells, ultimately leading to increased sperm count and motility. CONCLUSION/SIGNIFICANCE: M. pruriens efficiently recovers the spermatogenic loss induced due to EE administration. The recovery is mediated by reduction in ROS level, restoration of MMP, regulation of apoptosis and eventual increase in the number of germ cells and regulation of apoptosis. The present study simplified the complexity of mechanism involved and provided meaningful insights into MP/LD mediated correction of spermatogenic impairment caused by estrogens exposure. This is the first study demonstrating that L-DOPA largely accounts for pro-spermatogenic properties of M. pruriens. The manuscript bears CDRI communication number 8374.

Singh AP; Sarkar S; Tripathi M; Rajender S

2013-01-01

276

Mucuna pruriens and Its Major Constituent L-DOPA Recover Spermatogenic Loss by Combating ROS, Loss of Mitochondrial Membrane Potential and Apoptosis  

Science.gov (United States)

Background The Ayurvedic medicinal system claims Mucuna pruriens (MP) to possess pro-male fertility, aphrodisiac and adaptogenic properties. Some scientific evidence also supports its pro-male fertility properties; however, the mechanism of its action is not yet clear. The present study aimed at demonstrating spermatogenic restorative efficacy of MP and its major constituent L-DOPA (LD), and finding the possible mechanism of action thereof in a rat model. Methodology/Findings Ethinyl estradiol (EE) was administered at a rate of 3 mg/kg body weight (BW)/day for a period of 14 days to generate a rat model with compromised spermatogenesis. MP and LD were administered in two separate groups of these animals starting 15th day for a period of 56 days, and the results were compared with an auto-recovery (AR) group. Sperm count and motility, testis histo-architecture, level of reactive oxygen species (ROS), mitochondrial membrane potential (MMP), apoptosis, peripheral hormone levels and testicular germ cell populations were analysed, in all experimental groups. We observed efficient and quick recovery of spermatogenesis in MP and LD groups in comparison to the auto-recovery group. The treatment regulated ROS level, apoptosis, and mitochondrial membrane potential (MMP), recovered the hypothalamic-pituitary-gonadal axis and the number of testicular germ cells, ultimately leading to increased sperm count and motility. Conclusion/Significance M. pruriens efficiently recovers the spermatogenic loss induced due to EE administration. The recovery is mediated by reduction in ROS level, restoration of MMP, regulation of apoptosis and eventual increase in the number of germ cells and regulation of apoptosis. The present study simplified the complexity of mechanism involved and provided meaningful insights into MP/LD mediated correction of spermatogenic impairment caused by estrogens exposure. This is the first study demonstrating that L-DOPA largely accounts for pro-spermatogenic properties of M. pruriens. The manuscript bears CDRI communication number 8374.

Singh, Akhand Pratap; Sarkar, Saumya; Tripathi, Muktanand; Rajender, Singh

2013-01-01

277

The role of ROS in microcystin-LR-induced hepatocyte apoptosis and liver injury in mice.  

UK PubMed Central (United Kingdom)

Microcystin-LR (MC-LR) produced by cyanobacteria in diverse water systems is a potent specific hepatotoxin and has been documented to induce hepatocyte apoptosis and liver injury; however, the mechanisms have not been fully elucidated. In the present study, we investigated whether MC-LR stimulated ROS generation in the liver of mice and the role of ROS in the pathogenesis of MC-LR-induced liver injury in vivo. MC-LR treatment (60 microg/kg of body weight) for 12h prompted large amount of ROS generation in mice liver, upregulated the expression of Bax and Bid, caused the mitochondrial membrane potential (MMP) loss and hepatocyte apoptosis as well as liver injury. While pretreatment with antioxidants, oral administration of vitamin C (250mg/kg of body weight, dissolved in double distill water) and vitamin E (200mg/kg of body weight, dissolved in corn oil) per day for 3 days continually, significantly reduced the generation of ROS and effectively inhibited the MC-LR-induced hepatocyte apoptosis and liver injury, suggesting that ROS played a critical role in MC-LR-induced hepatocyte apoptosis and liver injury. The protective effect of vitamin C and E also suggested the potential interest in the clinical treatment of MC-LR-induced liver injury and hepatotoxicity.

Weng D; Lu Y; Wei Y; Liu Y; Shen P

2007-03-01

278

Neferine from Nelumbo nucifera induces autophagy through the inhibition of PI3K/Akt/mTOR pathway and ROS hyper generation in A549 cells.  

Science.gov (United States)

Previously we have reported that neferine from the medicinal plant Nelumbo nucifera, inhibited cancer cell proliferation by inducing apoptosis. The present study was focused on the action mechanism of neferine in inducing autophagy in lung cancer cells. Neferine markedly inhibited A549 cell proliferation in a dose dependent manner. Acidic vesicular accumulation was observed in neferine treated cells as an indication of autophagy. Neferine could induce the conversion of LC3B-I to LC3B-II without affecting the expression levels of PI3KCIII and Beclin1. It has been observed that neferine mediated autophagy is dependent on inhibition of PI3K/Akt/mTOR signaling by neferine. Neferine treatment could also lead to the ROS hypergeneration and depletion of cellular antioxidant, GSH. The results demonstrate that neferine-induced autophagy is mediated through ROS hypergeneration and mTOR inhibition. Taken together, the present study unveils a novel mechanism of action of neferine on lung cancer cells in the induction of autophagy. PMID:23993526

Poornima, Paramasivan; Weng, Ching Feng; Padma, Viswanadha Vijaya

2013-06-07

279

Neferine from Nelumbo nucifera induces autophagy through the inhibition of PI3K/Akt/mTOR pathway and ROS hyper generation in A549 cells.  

UK PubMed Central (United Kingdom)

Previously we have reported that neferine from the medicinal plant Nelumbo nucifera, inhibited cancer cell proliferation by inducing apoptosis. The present study was focused on the action mechanism of neferine in inducing autophagy in lung cancer cells. Neferine markedly inhibited A549 cell proliferation in a dose dependent manner. Acidic vesicular accumulation was observed in neferine treated cells as an indication of autophagy. Neferine could induce the conversion of LC3B-I to LC3B-II without affecting the expression levels of PI3KCIII and Beclin1. It has been observed that neferine mediated autophagy is dependent on inhibition of PI3K/Akt/mTOR signaling by neferine. Neferine treatment could also lead to the ROS hypergeneration and depletion of cellular antioxidant, GSH. The results demonstrate that neferine-induced autophagy is mediated through ROS hypergeneration and mTOR inhibition. Taken together, the present study unveils a novel mechanism of action of neferine on lung cancer cells in the induction of autophagy.

Poornima P; Weng CF; Padma VV

2013-12-01

280

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 “-omics” 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

 
 
 
 
281

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

UK PubMed Central (United Kingdom)

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 "-omics" 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 P; Barba-Espín G; Hernández JA

2013-10-01

282

Reactive oxygen species (ROS)--induced genetic and epigenetic alterations in human carcinogenesis.  

UK PubMed Central (United Kingdom)

Cancer is a multistage and complex process characterized by molecular alterations that underlie all three phases of its development: (i) initiation, (ii) promotion and (iii) progression. Some of these molecular events include alterations in gene expression that are regulated by both genetic and epigenetic mechanisms. On the other hand, "oxidative stress" implies a cellular state where ROS production exceeds the cell's ability to metabolize them resulting in excessive accumulation of ROS that overwhelms cellular defenses. Such state has been shown to regulate both genetic and epigenetic cascades underlying altered gene expression in human disease including cancer. Throughout this manuscript, we review the current state of knowledge on the role of ROS-induced oxidative stress in altering the genetic and epigenetic involvement during human carcinogenesis.

Ziech D; Franco R; Pappa A; Panayiotidis MI

2011-06-01

283

Effects of a cationic PAMAM dendrimer on photosynthesis and ROS production of Chlamydomonas reinhardtii.  

Science.gov (United States)

Poly(amidoamine) (PAMAM) dendrimers hold great promises for biomedicine. This study sought to examine the toxicity of generation 4 (G4) cationic PAMAM dendrimer to the green microalga, Chlamydomonas reinhardtii, using physiological and molecular biomarkers. Results revealed that the G4 dendrimer at 15 and 25 nM stimulated the photosynthetic process and the production of reactive oxygen species (ROS) in algae. However, the over-production of ROS did not induce the expression of antioxidant enzyme genes, catalase and glutathione peroxidase. In addition, genes encoding light-harvesting proteins (lhca and lhcb), a ferredoxin (fdx) and an oxygen-evolving enhancer protein (psb) involved in photosynthesis were repressed after treatment. Nevertheless, the expression of the lhcbm9 gene, encoding a major light harvesting polypeptide, was increased. These results suggest that the strong modulation of photosynthesis induced by the dendrimer could lead to elevated ROS levels in microalgae. PMID:21554014

Petit, Anne-Noëlle; Debenest, Timothée; Eullaffroy, Philippe; Gagné, François

2011-05-09

284

Effects of a cationic PAMAM dendrimer on photosynthesis and ROS production of Chlamydomonas reinhardtii.  

UK PubMed Central (United Kingdom)

Poly(amidoamine) (PAMAM) dendrimers hold great promises for biomedicine. This study sought to examine the toxicity of generation 4 (G4) cationic PAMAM dendrimer to the green microalga, Chlamydomonas reinhardtii, using physiological and molecular biomarkers. Results revealed that the G4 dendrimer at 15 and 25 nM stimulated the photosynthetic process and the production of reactive oxygen species (ROS) in algae. However, the over-production of ROS did not induce the expression of antioxidant enzyme genes, catalase and glutathione peroxidase. In addition, genes encoding light-harvesting proteins (lhca and lhcb), a ferredoxin (fdx) and an oxygen-evolving enhancer protein (psb) involved in photosynthesis were repressed after treatment. Nevertheless, the expression of the lhcbm9 gene, encoding a major light harvesting polypeptide, was increased. These results suggest that the strong modulation of photosynthesis induced by the dendrimer could lead to elevated ROS levels in microalgae.

Petit AN; Debenest T; Eullaffroy P; Gagné F

2012-05-01

285

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

Science.gov (United States)

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 "-omics" 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. PMID:23812175

Diaz-Vivancos, Pedro; Barba-Espín, Gregorio; Hernández, José Antonio

2013-06-29

286

Bioactive polyphenol antioxidants protect oral fibroblasts from ROS-inducing agents.  

UK PubMed Central (United Kingdom)

BACKGROUND: Oxidative damage to soft oral tissues may result from exposure to the chemicals or biochemicals found in teeth-whitening products, dental restorations, tobacco, and alcohol. Our working hypothesis is that oral tissues are susceptible to the toxic effects of stressors such as hydrogen peroxide (H(2)O(2)), ethanol (EtOH) and nicotine (Nic), which decrease cell viability/DNA synthesis and elevate reactive oxygen species (ROS). In this study, we investigated specific polyphenols and turmeric derivative antioxidants (AO) in combinations that counteracted the effects of these stressors on cultured oral fibroblast proliferation and ROS production. METHODS: Oral fibroblasts were exposed to stressors for 30 min and then treated with 10(-5) M of bioactive AO mixtures [resveratrol, ferulic acid and tetrahydrocurcuminoid (RFT), phloretin, ferulic acid and resveratrol (PFR), phloretin, ferulic acid and tetrahydrocurcuminoid (PFT)] for 24 h. Cell viability and DNA synthesis were monitored using incorporated 3-[4,5-dimethylthiazol-2-yl]-5-[3-carboxymethoxyphenyl]-2-[4-sulphophenyl]-2H-tetrazolium (MTS) and 5-bromo-2-deoxyuridine (BrdU) assays, respectively. Total ROS was measured with dichlorodihydrofluorescein diacetate (H(2)DCFDA). RESULTS: Incubation of oral fibroblasts in the stressors for 30 min resulted in a dose-dependent decrease of DNA synthesis and number of viable cells, and an increased total ROS activity. AO treatment counteracted the insults by restoring DNA synthesis levels and cell viability, and decreasing the total ROS activity. CONCLUSION: The AO combinations of RFT, PFR and PFT protected the oral fibroblasts from the detrimental effects of H(2)O(2), EtOH and Nic by decreasing total ROS and increasing cell viability and DNA synthesis.

San Miguel SM; Opperman LA; Allen EP; Zielinski J; Svoboda KK

2012-12-01

287

?????? ?????? ??? ???????? ???????? ?? ??????? ???? (?? ?????????? ???????????-????????????? ?????-??????) | Verlibro vertimo ? rus? kalb? praradim? analiz? (Literat?ros vertimo mokyklos-studijos duomenimis)  

Directory of Open Access Journals (Sweden)

Full Text Available Straipsnyje Tartu Literat?ros vertimo mokyklos-studijos duomenimis analizuojamas eiliavimo b?das verlibras, kur? d?l neaiškaus metro ir tariamo paprastumo beveik visuomei b?na sud?tinga išversti ? rus? kalb?. Kaip taisykl?, verlibras nemetriškas, neturi rim? ir dažnai net nesilaikant aliteracijos principo. Straipsnyje pademonstruoti ?vair?s verlibro vertimo b?dai, pateikiami atlikti Literat?ros vertimo mokyklos-studijos student? vertimo iš rus? ? est? kalb? pavyzdžiai. ir atlikt? vertim? praradim? analiz?. Autoriaus siekis buvo atskleisti verlibro, labai sunkiai „priskiepijamo“ rus? eil?darai, vertim? b?d? sistemiškum?.

????? ????????

2006-01-01

288

Inhibition of Propionibacterium acnes-induced mediators of inflammation by Indian herbs.  

Science.gov (United States)

Propionibacterium acnes, an anaerobic pathogen, plays an important role in the pathogenesis of acne by inducing certain inflammatory mediators. These mediators include reactive oxygen species (ROS) and pro-inflammatory cytokines. In the present study, ROS, interleukin-8 (IL-8) and tumor necrosis factor-alpha (TNF-alpha) were used as the major criteria for the evaluation of anti-inflammatory activity. To prove the anti-inflammatory effects of herbs, polymorphonuclear leukocytes (PMNL) and monocytes were treated with culture supernatant of P. acnes in the presence or absence of herbs. It was found that Rubia cordifolia, Curcuma longa, Hemidesmus indicus, and Azadirachta indica caused a statistically significant suppression of ROS from PMNL. Sphaeranthus indicus caused a smaller, still significant suppression of ROS. Aloe vera had no effect on ROS production. In the case of proinflammatory cytokine-induced monocytes, maximum suppression was shown by Azadirachta indica and Sphaeranthus indicus, followed by Hemidesmus indicus, Rubia cordifolia, and Curcuma longa. Aloe vera showed insignificant inhibitory activity. Thus, these herbs shows anti-inflammatory activity by suppressing the capacity of P. acnes-induced ROS and pro-inflammatory cytokines, the two important inflammatory mediators in acne pathogenesis. PMID:12622461

Jain, A; Basal, E

2003-01-01

289

Inhibition of Propionibacterium acnes-induced mediators of inflammation by Indian herbs.  

UK PubMed Central (United Kingdom)

Propionibacterium acnes, an anaerobic pathogen, plays an important role in the pathogenesis of acne by inducing certain inflammatory mediators. These mediators include reactive oxygen species (ROS) and pro-inflammatory cytokines. In the present study, ROS, interleukin-8 (IL-8) and tumor necrosis factor-alpha (TNF-alpha) were used as the major criteria for the evaluation of anti-inflammatory activity. To prove the anti-inflammatory effects of herbs, polymorphonuclear leukocytes (PMNL) and monocytes were treated with culture supernatant of P. acnes in the presence or absence of herbs. It was found that Rubia cordifolia, Curcuma longa, Hemidesmus indicus, and Azadirachta indica caused a statistically significant suppression of ROS from PMNL. Sphaeranthus indicus caused a smaller, still significant suppression of ROS. Aloe vera had no effect on ROS production. In the case of proinflammatory cytokine-induced monocytes, maximum suppression was shown by Azadirachta indica and Sphaeranthus indicus, followed by Hemidesmus indicus, Rubia cordifolia, and Curcuma longa. Aloe vera showed insignificant inhibitory activity. Thus, these herbs shows anti-inflammatory activity by suppressing the capacity of P. acnes-induced ROS and pro-inflammatory cytokines, the two important inflammatory mediators in acne pathogenesis.

Jain A; Basal E

2003-01-01

290

The other face of ROS: a driver of stem cell expansion in colorectal cancer.  

Science.gov (United States)

APC mutations causing Wnt activation are commonly found in colorectal cancer, but downstream pathways that facilitate tumorigenesis are unclear. In this issue of Cell Stem Cell, Myant et al. (2013) show that Rac1 activation is required for Wnt-driven Lgr5+ intestinal stem cell transformation through ROS production and NF-kB activation. PMID:23746969

Pelicci, Pier Giuseppe; Dalton, Paola; Giorgio, Marco

2013-06-01

291

Late ROS accumulation and radiosensitivity in SOD1-overexpressing human glioma cells.  

Science.gov (United States)

This study investigates the hypothesis that CuZn superoxide dismutase (SOD1) overexpression confers radioresistance to human glioma cells by regulating the late accumulation of reactive oxygen species (ROS) and the G(2)/M-checkpoint pathway. U118-9 human glioma cells (wild type, neo vector control, and stably overexpressing SOD1) were irradiated (0-10 Gy) and assayed for cell survival, cellular ROS levels, cell-cycle-phase distributions, and cyclin B1 expression. SOD1-overexpressing cells were radioresistant compared to wild-type (wt) and neo vector control (neo) cells. Irradiated wt and neo cells showed a significant increase (approximately twofold) in DHE fluorescence beginning at 2 days postirradiation, which remained elevated at 8 days postirradiation. Interestingly, the late accumulation of ROS was suppressed in irradiated SOD1-overexpressing cells. The increase in ROS levels was followed by a decrease in cell growth and viability and an increase in the percentage of cells with sub-G(1) DNA content. SOD1 overexpression enhanced radiation-induced G(2) accumulation within 24 h postirradiation, which was accompanied by a decrease in cyclin B1 mRNA and protein levels. These results support the hypothesis that long after radiation exposure a "metabolic redox response" regulates radiosensitivity of human glioma cells. PMID:18790046

Gao, Zhen; Sarsour, Ehab H; Kalen, Amanda L; Li, Ling; Kumar, Maneesh G; Goswami, Prabhat C

2008-08-14

292

Late ROS-accumulation and Radiosensitivity in CuZnSOD Overexpressing Human Glioma Cells  

Science.gov (United States)

This study investigates the hypothesis that CuZn-superoxide dismutase (SOD1) overexpression confers radioresistance to human glioma cells by regulating the late accumulation of reactive oxygen species (ROS) and G2/M checkpoint pathway. U118-9 human glioma cells (wild type, neo vector control, and stably overexpressing SOD1) were irradiated (0-10 Gy) and assayed for cell survival, cellular ROS levels, cell cycle phase distributions, and cyclin B1 expression. SOD1 overexpressing cells were radioresistant compared to wild type (wt) and neo vector control (neo) cells. Irradiated wt and neo cells showed a significant increase (~2-fold) in DHE-fluorescence beginning at 2 d post-irradiation, which remained elevated at 8 d post-irradiation. Interestingly, the late accumulation of ROS was suppressed in irradiated SOD1-overexpressing cells. The increase in ROS levels was followed by a decrease in cell growth and viability, and an increase in the percentage of cells with sub G1 DNA content. SOD1 overexpression enhanced radiation-induced G2-accumulation within 24 h post-irradiation, which was accompanied with a decrease in cyclin B1 mRNA and protein levels. These results support the hypothesis that long after the radiation exposure a “metabolic redox-response” regulates radiosensitivity of human glioma cells.

Gao, Zhen; Sarsour, Ehab H.; Kalen, Amanda L.; Li, Ling; Kumar, Maneesh G.; Goswami, Prabhat C.

2008-01-01

293

Photocatalytic ROS production and phototoxicity of titanium dioxide nanoparticles is dependent on solar UV radiation spectrum  

Science.gov (United States)

Generation of reactive oxygen species (ROS) by titanium dioxide nanoparticles (nano-TiO2) and its consequent phototoxicity to Daphnia magna were measured under different solar UV radiation spectrum by applying a series of optical filters in a solar simulator. Removing UVB (280-32...

294

Baicalein reduces lipopolysaccharide-induced inflammation via suppressing JAK/STATs activation and ROS production.  

UK PubMed Central (United Kingdom)

OBJECTIVE: To investigate the precise molecular mechanisms by which baicalein exerts beneficial biochemical activities in RAW264.7 macrophages treated with LPS. MATERIALS AND METHODS: RAW264.7 cells were cultured in the absence or presence of baicalein together with or without LPS. iNOS and COX-2 expression were measured by western blot and RT-PCR analyses. TNF-?, IL-1?, and IL-6 were determined by using double-antibody sandwich ELISA. Phosphorylations of JAK1 and JAK2, and of STAT1 and STAT3 were detected by western blotting. Nuclear translocation of STAT1 and STAT3 was visualized by confocal microscopy. ROS production was detected by ROS assay. RESULTS: Baicalein significantly reduced the phosphorylation of STAT1 and STAT3 and the phosphorylation of JAK1 and JAK2, but without affecting MAPKs phosphorylation in LPS-stimulated RAW264.7 cells. Baicalein suppressed the nuclear translocation of STAT1 and STAT3 and inhibited production of iNOS upon LPS-stimulation, resulting in the inhibition of releases of NO and pro-inflammatory cytokines such as IL-1?, IL-6, and TNF-?, in a dose-dependent manner. In addition, we found that baicalein reduced the LPS-induced accumulation of ROS, confirming that baicalein serves as an antioxidant. CONCLUSIONS: Our results suggested that suppressing JAK/STATs activation and interfering with ROS production might contribute to the anti-inflammatory action of baicalein in macrophages.

Qi Z; Yin F; Lu L; Shen L; Qi S; Lan L; Luo L; Yin Z

2013-09-01

295

Bisdemethoxycurcumin suppresses MCF-7 cells proliferation by inducing ROS accumulation and modulating senescence-related pathways.  

UK PubMed Central (United Kingdom)

Background: Bisdemethoxycurcumin (BDMC) is a natural derivative of curcumin present in the phenolic components extracted from the dried rhizome of Curcuma longa L. BDMC demonstrated potential chemotherapeutic activities but the underlying mechanisms have not been fully clarified. In the present study, the role of reactive oxidative species (ROS) in the anti-cancer effects of BDMC was investigated. Methods: MCF-7 cells were exposed to BDMC, and then the cell proliferation, colony formation ability and cell cycle profile were analyzed. Cellular ROS level was determined by flow cytometry and fluorescent microscope observation using specific fluorescent probes. Mitochondrial membrane potential (ym) was assessed using JC-1. In addition, effects of BDMC on senescence-related molecules were analyzed by western blot assay. Results: BDMC significantly inhibited MCF-7 breast cancer cell proliferation, while a rapid rise of the intracellular ROS level accompanied with a reduction of Dym were observed. In addition, BDMC activated the pro-apoptotic protein p53 and its downstream effector p21 as well as the cell cycle regulatory proteins p16 and its downstream effector retinoblastoma protein (Rb). All of these BDMC-induced effects were counteracted with the pre-incubation of the antioxidant N-acetylcysteine (NAC). Conclusions: These results suggested that BDMC-induced ROS accumulation may contribute to its inhibitory effect on MCF-7 cell viability through regulation of p53/p21 and p16/Rb pathways.

Li YB; Gao JL; Zhong ZF; Hoi PM; Lee SM; Wang YT

2013-01-01

296

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

Science.gov (United States)

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

2009-07-01

297

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

UK PubMed Central (United Kingdom)

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.

Diez B; Cordo Russo R; Teijo MJ; Hajos S; Batlle A; Fukuda H

2009-01-01

298

Integrating mitochondrial energetics, redox and ROS metabolic networks: a two-compartment model.  

Science.gov (United States)

To understand the mechanisms involved in the control and regulation of mitochondrial reactive oxygen species (ROS) levels, a two-compartment computational mitochondrial energetic-redox (ME-R) model accounting for energetic, redox, and ROS metabolisms is presented. The ME-R model incorporates four main redox couples (NADH/NAD(+), NADPH/NADP(+), GSH/GSSG, Trx(SH)(2)/TrxSS). Scavenging systems-glutathione, thioredoxin, superoxide dismutase, catalase-are distributed in mitochondrial matrix and extra-matrix compartments, and transport between compartments of ROS species (superoxide: O(2)(?-), hydrogen peroxide: H(2)O(2)), and GSH is also taken into account. Model simulations are compared with experimental data obtained from isolated heart mitochondria. The ME-R model is able to simulate: i), the shape and order of magnitude of H(2)O(2) emission and dose-response kinetics observed after treatment with inhibitors of the GSH or Trx scavenging systems and ii), steady and transient behavior of ??(m) and NADH after single or repetitive pulses of substrate- or uncoupler-elicited energetic-redox transitions. The dynamics of the redox environment in both compartments is analyzed with the model following substrate addition. The ME-R model represents a useful computational tool for exploring ROS dynamics, the role of compartmentation in the modulation of the redox environment, and how redox regulation participates in the control of mitochondrial function. PMID:23442855

Kembro, Jackelyn M; Aon, Miguel A; Winslow, Raimond L; O'Rourke, Brian; Cortassa, Sonia

2013-01-22

299

The other face of ROS: a driver of stem cell expansion in colorectal cancer.  

UK PubMed Central (United Kingdom)

APC mutations causing Wnt activation are commonly found in colorectal cancer, but downstream pathways that facilitate tumorigenesis are unclear. In this issue of Cell Stem Cell, Myant et al. (2013) show that Rac1 activation is required for Wnt-driven Lgr5+ intestinal stem cell transformation through ROS production and NF-kB activation.

Pelicci PG; Dalton P; Giorgio M

2013-06-01

300

Identification of MV-generated ROS responsive EST clones in floral buds of Litchi chinensis Sonn.  

UK PubMed Central (United Kingdom)

KEY MESSAGE: A suppression subtractive hybridization library was constructed using inflorescence primordia of 'Nuomici' litchi to identify EST clones responsive to MV-generated ROS. 93 ESTs could be aligned as unique gene sequences in the inflorescence primordia of litchi. Litchi is an evergreen woody tree widely cultivated in subtropical and tropical regions. However, defective flowering is a pending problem of litchi production. Our previous study indicated that reactive oxygen species (ROS) induced by methyl viologen dichloride hydrate (MV) promotes flowering in litchi. In the present study, a suppression subtractive hybridization (SSH) library was constructed using inflorescence primordia of 'Nuomici' with the aim to find out ROS responsive clones during floral differentiation. 1856 Expressed sequence tag (EST) clones were randomly selected. Clones carrying single exogenous fragments were screened by reverse northern analysis to identify those responsive to MV-generated ROS. A total of 783 differentially expressed EST clones were identified as MV responsive cDNA and were subjected to sequencing. Among them, 26 clones were represented more than three times. 783 clones were aligned to 93 unique gene sequences. The unique genes were classified into 9 categories. 16 % of them were involved in transport facilitation, 11 % in transcription regulation, 4 % in stress response, 9 % in carbohydrate metabolism, 1 % in secondary metabolism, 14 % in intracellular signaling, and 25 % in other metabolism, while 9 % were genes with unknown functions and 11 % were genes with no match in the database.

Liu WW; Kim HJ; Chen HB; Lu XY; Zhou BY

2013-09-01

 
 
 
 
301

The Chinese Understanding of Cultural Industries Kult?ros industrij? samprata Kinijoje  

Directory of Open Access Journals (Sweden)

Full Text Available Cultural industries in China always receive much support from governments and are developing quite fast. This paper will explain the concept of cultural industries in China and show the history of China’s Cultural Industries from the perspective of policy. And there will be a detailed analysis of the situation of this sector by a number of latest figures and data which are from social surveys lasting for 6 months around the nation. Then the paper will discuss the problems and opportunities of Chinese cultural industries.Article in EnglishKult?ros industrijos Kinijoje visada buvo stipriai remiamos vyriausyb?s ir spar?iai vyst?si. Straipsnio tikslas – paaiškinti kult?ros industrij? samprat? ir atskleisti šalies kult?ros industrij? istorij?, iliustruojant naujausiais duomenimis ir skai?iais, kurie gauti tyrimo, trukusio 6 m?nesius visoje Kinijoje, metu. Straipsnyje aptariamos Kinijos kult?ros industrij? problemos ir galimyb?s.Straipsnis angl? kalba

Yang Jianfei

2011-01-01

302

Superparamagnetic iron oxide nanoparticles: amplifying ROS stress to improve anticancer drug efficacy.  

UK PubMed Central (United Kingdom)

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-micelles can synergize with ?-lap for improved cancer therapy. These SPION-micelles selectively release iron ions inside cancer cells, which interact with hydrogen peroxide (H(2)O(2)) generated from ?-lap in a tumor-specific, NQO1-dependent manner. Through Fenton reactions, these iron ions escalate the ROS stress in ?-lap-exposed cancer cells, thereby greatly enhancing the therapeutic index of ?-lap. More specifically, a 10-fold increase in ROS stress was detected in ?-lap-exposed cells pretreated with SPION-micelles over those treated with ?-lap alone, which also correlates with significantly increased cell death. Catalase treatment of cells or administration of an iron chelator can block the therapeutic synergy. Our data suggest that incorporation of SPION-micelles with ROS-generating drugs can potentially improve drug efficacy during cancer treatment, thereby provides a synergistic strategy to integrate imaging and therapeutic functions in the development of theranostic nanomedicine.

Huang G; Chen H; Dong Y; Luo X; Yu H; Moore Z; Bey EA; Boothman DA; Gao J

2013-01-01

303

Rare-earth atom motions in ROs4Sb12 (R = La, Pr, Nd, Sm)  

International Nuclear Information System (INIS)

High-resolution inelastic x-ray scattering (IXS) was carried out in the filled-skutterudites ROs4Sb12 (R = La, Pr, Nd, Sm). Low-energy rare-earth modes were found in these compounds. They show significant rare-earth dependence, suggesting a correlation with lanthanide contraction. We discuss the relation between the present IXS measurements and reported other experiments.

2010-01-01

304

Intracellular ROS protection efficiency and free radical-scavenging activity of curcumin.  

Science.gov (United States)

Curcumin has many pharmaceutical applications, many of which arise from its potent antioxidant properties. The present research examined the antioxidant activities of curcumin in polar solvents by a comparative study using ESR, reduction of ferric iron in aqueous medium and intracellular ROS/toxicity assays. ESR data indicated that the steric hindrance among adjacent big size groups within a galvinoxyl molecule limited the curcumin to scavenge galvinoxyl radicals effectively, while curcumin showed a powerful capacity for scavenging intracellular smaller oxidative molecules such as H?O?, HO•, ROO•. Cell viability and ROS assays demonstrated that curcumin was able to penetrate into the polar medium inside the cells and to protect them against the highly toxic and lethal effects of cumene hydroperoxide. Curcumin also showed good electron-transfer capability, with greater activity than trolox in aqueous solution. Curcumin can readily transfer electron or easily donate H-atom from two phenolic sites to scavenge free radicals. The excellent electron transfer capability of curcumin is because of its unique structure and different functional groups, including a ?-diketone and several ? electrons that have the capacity to conjugate between two phenyl rings. Therfore, since curcumin is inherently a lipophilic compound, because of its superb intracellular ROS scavenging activity, it can be used as an effective antioxidant for ROS protection within the polar cytoplasm. PMID:22016801

Barzegar, Abolfazl; Moosavi-Movahedi, Ali A

2011-10-10

305

Intracellular ROS protection efficiency and free radical-scavenging activity of curcumin.  

UK PubMed Central (United Kingdom)

Curcumin has many pharmaceutical applications, many of which arise from its potent antioxidant properties. The present research examined the antioxidant activities of curcumin in polar solvents by a comparative study using ESR, reduction of ferric iron in aqueous medium and intracellular ROS/toxicity assays. ESR data indicated that the steric hindrance among adjacent big size groups within a galvinoxyl molecule limited the curcumin to scavenge galvinoxyl radicals effectively, while curcumin showed a powerful capacity for scavenging intracellular smaller oxidative molecules such as H?O?, HO•, ROO•. Cell viability and ROS assays demonstrated that curcumin was able to penetrate into the polar medium inside the cells and to protect them against the highly toxic and lethal effects of cumene hydroperoxide. Curcumin also showed good electron-transfer capability, with greater activity than trolox in aqueous solution. Curcumin can readily transfer electron or easily donate H-atom from two phenolic sites to scavenge free radicals. The excellent electron transfer capability of curcumin is because of its unique structure and different functional groups, including a ?-diketone and several ? electrons that have the capacity to conjugate between two phenyl rings. Therfore, since curcumin is inherently a lipophilic compound, because of its superb intracellular ROS scavenging activity, it can be used as an effective antioxidant for ROS protection within the polar cytoplasm.

Barzegar A; Moosavi-Movahedi AA

2011-01-01

306

Intracellular ROS Protection Efficiency and Free Radical-Scavenging Activity of Curcumin  

Science.gov (United States)

Curcumin has many pharmaceutical applications, many of which arise from its potent antioxidant properties. The present research examined the antioxidant activities of curcumin in polar solvents by a comparative study using ESR, reduction of ferric iron in aqueous medium and intracellular ROS/toxicity assays. ESR data indicated that the steric hindrance among adjacent big size groups within a galvinoxyl molecule limited the curcumin to scavenge galvinoxyl radicals effectively, while curcumin showed a powerful capacity for scavenging intracellular smaller oxidative molecules such as H2O2, HO•, ROO•. Cell viability and ROS assays demonstrated that curcumin was able to penetrate into the polar medium inside the cells and to protect them against the highly toxic and lethal effects of cumene hydroperoxide. Curcumin also showed good electron-transfer capability, with greater activity than trolox in aqueous solution. Curcumin can readily transfer electron or easily donate H-atom from two phenolic sites to scavenge free radicals. The excellent electron transfer capability of curcumin is because of its unique structure and different functional groups, including a ?-diketone and several ? electrons that have the capacity to conjugate between two phenyl rings. Therfore, since curcumin is inherently a lipophilic compound, because of its superb intracellular ROS scavenging activity, it can be used as an effective antioxidant for ROS protection within the polar cytoplasm.

Barzegar, Abolfazl; Moosavi-Movahedi, Ali A.

2011-01-01

307

Neurocalcin delta modulation of ROS-GC1, a new model of Ca(2+) signaling.  

UK PubMed Central (United Kingdom)

ROS-GC1 membrane guanylate cyclase is a Ca(2+) bimodal signal transduction switch. It is turned "off" by a rise in free Ca(2+) from nanomolar to the semicromolar range in the photoreceptor outer segments and the olfactory bulb neurons; by a similar rise in the bipolar and ganglion retinal neurons it is turned "on". These opposite operational modes of the switch are specified by its Ca(2+) sensing devices, respectively termed GCAPs and CD-GCAPs. Neurocalcin delta is a CD-GCAP. In the present study, the neurocalcin delta-modulated site, V(837)-L(858), in ROS-GC1 has been mapped. The location and properties of this site are unique. It resides within the core domain of the catalytic module and does not require the alpha-helical dimerization domain structural element (amino acids 767-811) for activating the catalytic module. Contrary to the current beliefs, the catalytic module is intrinsically active; it is directly regulated by the neurocalcin delta-modulated Ca(2+) signal and is dimeric in nature. A fold recognition based model of the catalytic domain of ROS-GC1 was built, and neurocalcin delta docking simulations were carried out to define the three-dimensional features of the interacting domains of the two molecules. These findings define a new transduction model for the Ca(2+) signaling of ROS-GC1.

Venkataraman V; Duda T; Ravichandran S; Sharma RK

2008-06-01

308

Neurocalcin ? Modulation of ROS-GC1, a New Model of Ca2+ Signaling†  

Science.gov (United States)

ROS-GC1 membrane guanylate cyclase is a Ca2+ bimodal signal transduction switch. It is turned “off” by a rise in free Ca2+ from nanomolar to the semicromolar range in the photoreceptor outer segments and the olfactory bulb neurons; by a similar rise in the bipolar and ganglion retinal neurons it is turned “on”. These opposite operational modes of the switch are specified by its Ca2+ sensing devices, respectively termed GCAPs and CD-GCAPs. Neurocalcin ? is a CD-GCAP. In the present study, the neurocalcin ?-modulated site, V837–L858, in ROS-GC1 has been mapped. The location and properties of this site are unique. It resides within the core domain of the catalytic module and does not require the ?-helical dimerization domain structural element (amino acids 767–811) for activating the catalytic module. Contrary to the current beliefs, the catalytic module is intrinsically active; it is directly regulated by the neurocalcin ?-modulated Ca2+ signal and is dimeric in nature. A fold recognition based model of the catalytic domain of ROS-GC1 was built, and neurocalcin ? docking simulations were carried out to define the three-dimensional features of the interacting domains of the two molecules. These findings define a new transduction model for the Ca2+ signaling of ROS-GC1.

Venkataraman, Venkateswar; Duda, Teresa; Ravichandran, Sarangan; Sharma, Rameshwar K.

2008-01-01

309

Neurocalcin delta modulation of ROS-GC1, a new model of Ca(2+) signaling.  

Science.gov (United States)

ROS-GC1 membrane guanylate cyclase is a Ca(2+) bimodal signal transduction switch. It is turned "off" by a rise in free Ca(2+) from nanomolar to the semicromolar range in the photoreceptor outer segments and the olfactory bulb neurons; by a similar rise in the bipolar and ganglion retinal neurons it is turned "on". These opposite operational modes of the switch are specified by its Ca(2+) sensing devices, respectively termed GCAPs and CD-GCAPs. Neurocalcin delta is a CD-GCAP. In the present study, the neurocalcin delta-modulated site, V(837)-L(858), in ROS-GC1 has been mapped. The location and properties of this site are unique. It resides within the core domain of the catalytic module and does not require the alpha-helical dimerization domain structural element (amino acids 767-811) for activating the catalytic module. Contrary to the current beliefs, the catalytic module is intrinsically active; it is directly regulated by the neurocalcin delta-modulated Ca(2+) signal and is dimeric in nature. A fold recognition based model of the catalytic domain of ROS-GC1 was built, and neurocalcin delta docking simulations were carried out to define the three-dimensional features of the interacting domains of the two molecules. These findings define a new transduction model for the Ca(2+) signaling of ROS-GC1. PMID:18500817

Venkataraman, Venkateswar; Duda, Teresa; Ravichandran, Sarangan; Sharma, Rameshwar K

2008-06-24

310

Integrating mitochondrial energetics, redox and ROS metabolic networks: a two-compartment model.  

UK PubMed Central (United Kingdom)

To understand the mechanisms involved in the control and regulation of mitochondrial reactive oxygen species (ROS) levels, a two-compartment computational mitochondrial energetic-redox (ME-R) model accounting for energetic, redox, and ROS metabolisms is presented. The ME-R model incorporates four main redox couples (NADH/NAD(+), NADPH/NADP(+), GSH/GSSG, Trx(SH)(2)/TrxSS). Scavenging systems-glutathione, thioredoxin, superoxide dismutase, catalase-are distributed in mitochondrial matrix and extra-matrix compartments, and transport between compartments of ROS species (superoxide: O(2)(?-), hydrogen peroxide: H(2)O(2)), and GSH is also taken into account. Model simulations are compared with experimental data obtained from isolated heart mitochondria. The ME-R model is able to simulate: i), the shape and order of magnitude of H(2)O(2) emission and dose-response kinetics observed after treatment with inhibitors of the GSH or Trx scavenging systems and ii), steady and transient behavior of ??(m) and NADH after single or repetitive pulses of substrate- or uncoupler-elicited energetic-redox transitions. The dynamics of the redox environment in both compartments is analyzed with the model following substrate addition. The ME-R model represents a useful computational tool for exploring ROS dynamics, the role of compartmentation in the modulation of the redox environment, and how redox regulation participates in the control of mitochondrial function.

Kembro JM; Aon MA; Winslow RL; O'Rourke B; Cortassa S

2013-01-01

311

[Effects of resveratrol on apoptosis and ROS production in Hepa 1-6 hepatocarcinoma cells].  

UK PubMed Central (United Kingdom)

OBJECTIVE: To observe the effects of resveratrol on apoptosis and ROS production in murine hepatocarcinoma Hepa 1-6 cells in vitro. METHODS: Hepa 1-6 cells were treated with different dose of resveratrol (20 micromol/L, 40 micromol/L, 80 micromol/L). Cell proliferation was detected with MTT assay at 24 h, 48 h and 72 h. Hoechst 33258 staining was used to visualize apoptotic morphology. Cell apoptosis was detected by flow cytometry analysis. Activated caspase-3 was detected by western blot. Intracellular ROS production was observed by 2',7'-dichlorofluorescin diacetate (DCF-DA) staining. RESULTS: Compared with the control, upon treatment with 20-80 micromol/L resveratrol for 24 h, 48 h or 72 h, the proliferation of Hepa 1-6 cells was significantly inhibited in a time-dose dependent manner. 20-80 micromol/L resveratrol also induced apoptosis and apoptotic morphology change in Hepa 1-6 cells accompanied with caspase-3 activation and ROS generation. CONCLUSION: Resveratrol could inhibit cell proliferation, induce apoptosis in murine hepatocarcinoma Hepa 1-6 cells, and the mechanism may associated with caspase-3 activation and ROS production.

Du Q; Shen KP; Hu B; Deng S

2012-03-01

312

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.

Zafra Adoración; Rodríguez-García María; Alché Juan

2010-01-01

313

Thymoquinone Inhibits Tumor Growth and Induces Apoptosis in a Breast Cancer Xenograft Mouse Model: The Role of p38 MAPK and ROS  

Science.gov (United States)

Due to narrow therapeutic window of cancer therapeutic agents and the development of resistance against these agents, there is a need to discover novel agents to treat breast cancer. The antitumor activities of thymoquinone (TQ), a compound isolated from Nigella sativa oil, were investigated in breast carcinoma in vitro and in vivo. Cell responses after TQ treatment were assessed by using different assays including MTT assay, annexin V-propidium iodide staining, Mitosox staining and Western blot. The antitumor effect was studied by breast tumor xenograft mouse model, and the tumor tissues were examined by histology and immunohistochemistry. The level of anti-oxidant enzymes/molecules in mouse liver tissues was measured by commercial kits. Here, we show that TQ induced p38 phosphorylation and ROS production in breast cancer cells. These inductions were found to be responsible for TQ’s anti-proliferative and pro-apoptotic effects. Moreover, TQ-induced ROS production regulated p38 phosphorylation but not vice versa. TQ treatment was found to suppress the tumor growth and this effect was further enhanced by combination with doxorubicin. TQ also inhibited the protein expression of anti-apoptotic genes, such as XIAP, survivin, Bcl-xL and Bcl-2, in breast cancer cells and breast tumor xenograft. Reduced Ki67 and increased TUNEL staining were observed in TQ-treated tumors. TQ was also found to increase the level of catalase, superoxide dismutase and glutathione in mouse liver tissues. Overall, our results demonstrated that the anti-proliferative and pro-apoptotic effects of TQ in breast cancer are mediated through p38 phosphorylation via ROS generation.

Woo, Chern Chiuh; Hsu, Annie; Kumar, Alan Prem; Sethi, Gautam; Tan, Kwong Huat Benny

2013-01-01

314

Attenuation of Proinflammatory Responses by S-[6]-Gingerol via Inhibition of ROS/NF-Kappa B/COX2 Activation in HuH7 Cells  

Science.gov (United States)

Introduction. Hepatic inflammation underlies the pathogenesis of chronic diseases such as insulin resistance and type 2 diabetes mellitus. S-[6]-Gingerol has been shown to have anti-inflammatory properties. Important inflammatory mediators of interleukins include nuclear factor ?B (NF?B) and cyclooxygenase 2 (COX2). We now explore the mechanism of anti-inflammatory effects of S-[6]-gingerol in liver cells. Methods. HuH7 cells were stimulated with IL1? to establish an in vitro hepatic inflammatory model. Results. S-[6]-Gingerol attenuated IL1?-induced inflammation and oxidative stress in HuH7 cells, as evidenced by decreasing mRNA levels of inflammatory factor IL6, IL8, and SAA1, suppression of ROS generation, and increasing mRNA levels of DHCR24. In addition, S-[6]-gingerol reduced IL1?-induced COX2 upregulation as well as NF?B activity. Similar to the protective effects of S-[6]-gingerol, both NS-398 (a selective COX2 inhibitor) and PDTC (a selective NF?B inhibitor) suppressed mRNA levels of IL6, IL8, and SAA1. Importantly, PDTC attenuated IL1?-induced overexpression of COX2. Of particular note, the protective effect of S-[6]-gingerol against the IL1?-induced inflammatory response was similar to that of BHT, an ROS scavenger. Conclusions. The findings of this study demonstrate that S-[6]-gingerol protects HuH7 cells against IL1?-induced inflammatory insults through inhibition of the ROS/NF?B/COX2 pathway.

McGrath, Kristine C. Y.; Tran, Van H.; Li, Yi-Ming; Duke, Colin C.; Roufogalis, Basil D.; Heather, Alison K.

2013-01-01

315

Lipopolysaccharide/adenosine triphosphate-mediated signal transduction in the regulation of NLRP3 protein expression and caspase-1-mediated interleukin-1? secretion.  

UK PubMed Central (United Kingdom)

OBJECTIVE: Reactive oxygen species (ROS) plays a critical role in the regulation of NLRP3 inflammasome activation. However, the ROS-mediated signaling pathways controlling NLRP3 inflammasome activation are not well defined. METHODS: Using lipopolysaccharide (LPS) and adenosine triphosphate (ATP) activated murine macrophages as the testing model, cytokine release and protein expression were quantified by enzyme-linked immunosorbent assay and Western blot, respectively. ROS was scavenged by N-acetyl cysteine; NADPH oxidase, the major source of ROS, was inhibited by diphenyliodonium, apocynin or gp91-phox siRNA transfection; and protein kinase was inhibited by its specific inhibitor. RESULTS: LPS-induced NLRP3 protein expression was regulated through the NADPH oxidase/ROS/NF-?B-dependent, JAK2/PI3-kinase/AKT/NF-?B-dependent, and MAPK-dependent pathways, while ATP-induced caspase-1 activation was regulated through the NADPH oxidase/ROS-dependent pathway. CONCLUSIONS: These results demonstrate that ROS regulates not only the priming stage, but also the activation stage, of NLRP3 inflammasome activation in LPS + ATP-activated macrophages.

Liao PC; Chao LK; Chou JC; Dong WC; Lin CN; Lin CY; Chen A; Ka SM; Ho CL; Hua KF

2013-01-01

316

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

UK PubMed Central (United Kingdom)

Gluconacetobacter diazotrophicus, an endophyte isolated from sugarcane, is a strict aerobe that fixates N(2). 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.

Alquéres SM; Oliveira JH; Nogueira EM; Guedes HV; Oliveira PL; Câmara F; Baldani JI; Martins OB

2010-10-01

317

Nifedipine inhibits angiotensin II-induced cardiac fibrosis via downregulating Nox4-derived ROS generation and suppressing ERK1/2, JNK signaling pathways.  

UK PubMed Central (United Kingdom)

Nifedipine, a classic L-type dihydropyridine calcium channel blocker (CCB), has been reported to possess multiple cardioprotective properties. However, little is known about the effects of nifedipine on cardiac fibrosis induced by angiotensinII (AngII) and the detailed molecular mechanisms. In this study, we found that nifedipine attenuated AngII-induced cardiac fibrosis in vitro via inhibiting the proliferation, differentiation of cardiac fibroblasts and antagonizing the upregulation of extracellular matrix (ECM) protein fibronectin (FN) and the pro-fibrotic cytokine connective tissue growth factor (CTGF). Furthermore, nifedipine suppressed the upregulation of NAD(P)H oxidase 4 (Nox4) and the production of reactive oxygen species (ROS) induced by AngII. In addition, it markedly inhibited the phosphorylation of extracellular signal-regulate kinases 1/2 (ERK1/2) and c-Jun NH(2)-terminal kinase (JNK) stimulated by AngII. However, nifedipine exhibited no effect on the variation of intracellular Ca2+ concentration ([Ca2+]i). These results suggested that (1) nifedipine inhibited cardiac fibrosis induced by AngII; (2) the anti-fibrotic effects of nifedipine may be mediated by interfering with the production of ROS and the activation of ERK1/2 and JNK signaling pathways; (3) the classic calcium channel blocking action of nifedipine may not be involved in the anti-fibrotic activities.

Jia Y; Xu J; Yu Y; Guo J; Liu P; Chen S; Jiang J

2013-06-01

318

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

319

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

UK PubMed Central (United Kingdom)

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.

Kim MO; Moon DO; Jung JM; Lee WS; Choi YH; Kim GY

2011-01-01

320

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

Science.gov (United States)

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

2011-02-20

 
 
 
 
321

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

International Nuclear Information System (INIS)

[en] 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

322

Basal and T?-induced ROS production in lymphocyte mitochondria is increased in type 2 diabetic patients.  

Science.gov (United States)

Mitochondrial function, including production of reactive oxygen species (ROS), is important in the pathogenesis of diabetes and its complications. Thyroid hormones are major regulator of these processes. Hence, the aim of this study was to examine the thyroid hormone regulation of ROS production in human lymphocytes in patients with diabetes mellitus type 2 (T2DM). Lymphocytes from 10 controls and 10 persons with T2DM were examined. Mitochondrial membrane potential (MMP) was examined by flow cytometry after staining with MitoTracker Green (MTG). Similarly ROS was measured following staining with carboxy-H?DCFDA. MMP was increased in T2DM patients and T? stimulation increased MMP in controls [1398 a.u. (979-4094) vs. 2156 a.u. (1611-15189), p=0.04, median and quartiles] as well as in T2DM patients [9167 a.u. (7387-11746) vs. 20274 a.u. (17183-27839 p=0.004, median and quartiles]. Basal ROS concentration was increased in lymphocytes from T2DM and T? significantly stimulated ROS concentration in controls [3691 a.u. (2584-6396) vs. 5650 a.u. (3001-7802) p=0.013, median and quartiles] and in T2DM patients [19271 a.u. (6288-25282) vs. 23178 a.u. (10004-28857) p=0.013, median and quartiles]. The ratio of ROS production related to MMP was significantly higher in T2DM, unstimulated as well as T?-stimulated in T2DM. Unstimulated and T? stimulated ROS production and MMP were higher in lymphocytes from diabetic patients. An altered balance between ROS production and MMP, favoring ROS production in T2DM patients, was found suggesting that an increased mitochondrial sensitivity for T? may be a significant factor responsible for increased ROS activity in diabetic patients. PMID:23015613

Anthonsen, S; Larsen, J; Pedersen, P L; Dalgaard, L T; Kvetny, J

2012-09-26

323

Basal and T?-induced ROS production in lymphocyte mitochondria is increased in type 2 diabetic patients.  

UK PubMed Central (United Kingdom)

Mitochondrial function, including production of reactive oxygen species (ROS), is important in the pathogenesis of diabetes and its complications. Thyroid hormones are major regulator of these processes. Hence, the aim of this study was to examine the thyroid hormone regulation of ROS production in human lymphocytes in patients with diabetes mellitus type 2 (T2DM). Lymphocytes from 10 controls and 10 persons with T2DM were examined. Mitochondrial membrane potential (MMP) was examined by flow cytometry after staining with MitoTracker Green (MTG). Similarly ROS was measured following staining with carboxy-H?DCFDA. MMP was increased in T2DM patients and T? stimulation increased MMP in controls [1398 a.u. (979-4094) vs. 2156 a.u. (1611-15189), p=0.04, median and quartiles] as well as in T2DM patients [9167 a.u. (7387-11746) vs. 20274 a.u. (17183-27839 p=0.004, median and quartiles]. Basal ROS concentration was increased in lymphocytes from T2DM and T? significantly stimulated ROS concentration in controls [3691 a.u. (2584-6396) vs. 5650 a.u. (3001-7802) p=0.013, median and quartiles] and in T2DM patients [19271 a.u. (6288-25282) vs. 23178 a.u. (10004-28857) p=0.013, median and quartiles]. The ratio of ROS production related to MMP was significantly higher in T2DM, unstimulated as well as T?-stimulated in T2DM. Unstimulated and T? stimulated ROS production and MMP were higher in lymphocytes from diabetic patients. An altered balance between ROS production and MMP, favoring ROS production in T2DM patients, was found suggesting that an increased mitochondrial sensitivity for T? may be a significant factor responsible for increased ROS activity in diabetic patients.

Anthonsen S; Larsen J; Pedersen PL; Dalgaard LT; Kvetny J

2013-04-01

324

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; Shih Ruey-Horng; Lin Chih-Chung; Chen Jung-Tsan; Yang Chuen-Mao

2012-01-01

325

Integrin-mediated cell adhesion and spreading engage different sources of reactive oxygen species.  

Science.gov (United States)

The tightly regulated production of intracellular reactive oxygen species (ROS) participates in several biologic processes such as cellular growth, programmed cell death, senescence, and adhesion. It is increasingly evident that the same enzymatic processes that were originally linked to ROS generation during host defence or apoptosis execution are also involved in redox-mediated signal transduction. We investigated in murine NIH3T3 fibroblasts the contribution of a variety of redox-dependent events during signal transduction initiated by integrin engagement due to fibronectin stimulation and report that a mitochondrial ROS release occurs, strictly confined to the early phase of extracellular matrix (ECM) contact (10 min). Besides, 5-lipoxygenase (5-LOX) is engaged by integrin receptor ligation as another ROS source, contributing to the more-intense, second ROS burst (45 min), possibly orchestrating the spreading of cells in response to ECM contact. To define a potential mechanism for ROS signaling, we demonstrate that on integrin recruitment, the Src homology-2 domain-containing phosphatase 2 (SHP-2) undergoes a reversible oxidization/inactivation to which mitochondrial and 5-lipoxygenase ROS contribute differentially. In keeping with a key role of oxidants during integrin signaling, the inactivation of SHP-2 prevents the dephosphorylation and inactivation of SHP-2 substrates (p125FAK and SHPS-1), thus enabling the continued propagation of the signal arising by integrin engagement. PMID:17280488

Taddei, Maria Letizia; Parri, Matteo; Mello, Tommaso; Catalano, Alfonso; Levine, Alan D; Raugei, Giovanni; Ramponi, Giampietro; Chiarugi, Paola

2007-04-01

326

CDPK-driven changes in the intracellular ROS level and plant secondary metabolism.  

UK PubMed Central (United Kingdom)

Heterologous expression of a constitutively active calcium-dependent protein kinase (CDPK) gene was previously shown to increase secondary metabolite production in cultured cells of Rubia cordifolia, but the critical question of how CDPK activates secondary metabolism remains to be answered. In this article, we report that the expression of the Arabidopsis CDPK gene, AtCPK1, in R. cordifolia cells caused moderate and stable elevation of intracellular reactive oxygen species (ROS) levels. In contrast, the non-active, mutated AtCPK1 gene did not cause such an effect. The active AtCPK1 also increased cell size, likely by restricting cell division. These results are consistent with the model in which constitutive expression of AtCPK1 mimics the effects of elicitors, acting on secondary metabolism via the activation of ROS production.

Bulgakov VP; Gorpenchenko TY; Shkryl YN; Veremeichik GN; Mischenko NP; Avramenko TV; Fedoreyev SA; Zhuravlev YN

2011-11-01

327

New inhibitors of ROS generation and T-cell proliferation from Myrtus communis.  

UK PubMed Central (United Kingdom)

Phytochemical investigation on Myrtus communis Linn. afforded myrtucommuacetalone (1) with an unprecedented carbon skeleton and a new phloroglucinol-type compound, myrtucommulone M (2), along with four known constituents 3-6. Their structures were established by extensive analyses of NMR and mass spectral data as well as by single-crystal X-ray diffraction studies. These constituents were evaluated for their ability to modulate the immune response, based on their effects on various components of immune system. Compounds 1 and 5 exhibited significant inhibitory effect against nitric oxide (NO(•)) production. Compound 1 also exhibited significant antiproliferative activity (IC50 < 0.5 ?g/mL) against T-cell proliferation. Myricetin (3) exerted a significant inhibition (IC50 = 1.6 ?g/mL) on zymosan-stimulated whole blood phagocytes ROS production. Compounds 1 and 3 were active against PMA-stimulated ROS generation.

Choudhary MI; Khan N; Ahmad M; Yousuf S; Fun HK; Soomro S; Asif M; Mesaik MA; Shaheen F

2013-04-01

328

CDPK-driven changes in the intracellular ROS level and plant secondary metabolism.  

Science.gov (United States)

Heterologous expression of a constitutively active calcium-dependent protein kinase (CDPK) gene was previously shown to increase secondary metabolite production in cultured cells of Rubia cordifolia, but the critical question of how CDPK activates secondary metabolism remains to be answered. In this article, we report that the expression of the Arabidopsis CDPK gene, AtCPK1, in R. cordifolia cells caused moderate and stable elevation of intracellular reactive oxygen species (ROS) levels. In contrast, the non-active, mutated AtCPK1 gene did not cause such an effect. The active AtCPK1 also increased cell size, likely by restricting cell division. These results are consistent with the model in which constitutive expression of AtCPK1 mimics the effects of elicitors, acting on secondary metabolism via the activation of ROS production. PMID:22064507

Bulgakov, Victor P; Gorpenchenko, Tatiana Y; Shkryl, Yuri N; Veremeichik, Galina N; Mischenko, Natalia P; Avramenko, Tatiana V; Fedoreyev, Sergey A; Zhuravlev, Yuri N

2011-11-01

329

Current methods in quantifying ROS and oxidative damage in Caenorhabditis elegans and other model organism of ageing.  

UK PubMed Central (United Kingdom)

Accumulation of oxidative damage has been proposed to be causal to ageing as defined by the Free radical Theory of Ageing, which has been subject to recent debate. However, a major hurdle in understanding the biological roles of reactive oxygen species (ROS) signaling and their oxidative damage has been the widely recognized methodological difficulties to measure oxidative damage and ROS in vivo. In this review we describe the various novel approaches that have recently been developed to overcome this challenge in the nematode Caenorhabditis elegans, which is a paradigm invertebrate model organism for studying ageing and age-related disease given its short lifespan, easy genetics and transparency. In addition, we also discuss these methods in other important model organisms of ageing, including the budding yeast Saccharomyces cerevisiae, the fruitfly Drosophila melanogaster and the mouse Mus musculus. After an introduction on the various ROS that can be encountered, we discuss approaches for the detection and quantification of ROS and ROS damage of DNA, lipids and proteins, highlighting examples from literature to demonstrate the applicability and caveats of each method. As will become clear, combinations of approaches have now become possible and will prove essential for thoroughly understanding the involvement of ROS and ROS damage in the biology of ageing and disease.

Labuschagne CF; Brenkman AB

2013-09-01

330

Selenium compounds induce ROS in human high-metastatic large cell lung cancer cell line L9981  

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Full Text Available Background and objective It has been proved that methylseleninic acid (MSA) is a kind of artificially developed selenium compound, which appeared to be the best candidate for cancer prevention and therapy. Reduced glutathione is not only critical to MSA metabolism, but also is a kind of protective antioxidant which could remove the oxygen free radical promptly and maintain the intracellular redox status stable. The aim of this study is to explore the anticancer effects of ROS induced by MSA and the molecular mechanisms of MSA on induction of ROS. Methods We confirmed that MSA and selenite have the anticancer effect in the human high-metastatic large cell lung cancer cell line L9981 by growth inhibition detection, we detect the ROS induced by MSA and selenite in L9981 by fluorescence microscopy, and use flow cytometry to quantitate the ROS induced by NAC together with selenium compounds. Results ?MSA 2.5 ?M and 5.0 ?M selenite could inhibit the L9981 growth, Increasing the concentration resulted in a more pronounced effect. ?MSA and selenite could induce ROS in L9981. ?incubated NAC with selenite could significantly inhibit the ROS but increase the ROS treated by NAC with MSA. Conclusions ?MSA and selenite had anti-L9981 effect. ?Oxidative stress reaction may participate in the induction of apoptosis by MSA and selenite in lung cancer cell line L9981.

Chengfei LIU; Jun CHEN; Zhihao WU; Ying LI; Yu ZHU; Yuanrong REN; Qinghua ZHOU

2008-01-01

331

The Role of Mechanical Force and ROS in Integrin-Dependent Signals  

Science.gov (United States)

Cells are exposed to several types of integrin stimuli, which generate responses generally referred to as “integrin signals”, but the specific responses to different integrin stimuli are poorly defined. In this study, signals induced by integrin ligation during cell attachment, mechanical force from intracellular contraction, or cell stretching by external force were compared. The elevated phosphorylation levels of several proteins during the early phase of cell attachment and spreading of fibroblast cell lines were not affected by inhibition of ROCK and myosin II activity, i.e. the reactions occurred independently of intracellular contractile force acting on the adhesion sites. The contraction-independent phosphorylation sites included ERK1/2 T202/Y204, AKT S473, p130CAS Y410, and cofilin S3. In contrast to cell attachment, cyclic stretching of the adherent cells induced a robust phosphorylation only of ERK1/2 and the phosphorylation levels of the other investigated proteins were not or only moderately affected by stretching. No major differences between signaling via ?5?1 or ?v?3 integrins were detected. The importance of mitochondrial ROS for the integrin-induced signaling pathways was investigated using rotenone, a specific inhibitor of complex I in the respiratory chain. While rotenone only moderately reduced ATP levels and hardly affected the signals induced by cyclic cell stretching, it abolished the activation of AKT and reduced the actin polymerization rate in response to attachment in both cell lines. In contrast, scavenging of extracellular ROS with catalase or the vitamin C analog Asc-2P did not significantly influence the attachment-derived signaling, but caused a selective and pronounced enhancement of ERK1/2 phosphorylation in response to stretching. In conclusion, the results showed that “integrin signals” are composed of separate sets of reactions triggered by different types of integrin stimulation. Mitochondrial ROS and extracellular ROS had specific and distinct effects on the integrin signals induced by cell attachment and mechanical stretching.

Zeller, Kathrin S.; Riaz, Anjum; Sarve, Hamid; Li, Jia; Tengholm, Anders; Johansson, Staffan

2013-01-01

332

Increase of irradiation sensitivity on raji cells by rituximab through production of ROS  

International Nuclear Information System (INIS)

Objective: To observe the effects of rituximab (R) on cell death induced by X ray irradiation in Raji lymphoma cells and to evaluate its relationship with the intracellular production of reactive oxygen species (ROS). Methods: Raji cells were treated with low concentration of H2O2, rituximab (final concentration, 20 mg/L) for 24 h prior to irradiation (0- 10 Gy) or were treated with H2O2 combined with rituximab for 48 h. Cell survival was determined at an appropriate time point after treatment by the sulforhodamine B (SRB) test. The cells apoptosis with acridine orange-ethidium bromide (AO-EB) double staining were examined by fluorescence microscopy. The accumulation of ROS was assayed using 2',7'-dichlorofluorescein diacetate (DCFH-DA). Result: Compared with irradiation alone, the cell growth inhibition in Raji cells was enhanced by rituximab and irradiation combination treatment. The ID50 were 2.80 Gy and 5.58 Gy for rituximab + irradiation and irradiation, respectively. Low concentration of H2O2(20 ?M or 40 ?M), though non-cytotoxic, increased the radiosusceptibility of Raji cells in an concentration dependent manner. Rituximab in combination with irradiation induced an increasing intracellular ROS level and apoptotic cell death. An antioxidant, N-acetyl-L-cysteine (NAC), significantly attenuated the combination treatment-induced cell apoptosis. In addition, rituximab sensitized Raji cells to intracellular oxidative stress by H2O2, which showed the enhancement of cell growth inhibition and the increasing cell apoptosis. Conclusion: Rituximab harbors a significant in vitro radiosensitising effect by inducing significant cell apoptosis in Raji cells. ROS, serve as intracellular signaling molecules, probably play an important role in this event. (authors)

2009-01-01

333

The role of mechanical force and ROS in integrin-dependent signals.  

Science.gov (United States)

Cells are exposed to several types of integrin stimuli, which generate responses generally referred to as "integrin signals", but the specific responses to different integrin stimuli are poorly defined. In this study, signals induced by integrin ligation during cell attachment, mechanical force from intracellular contraction, or cell stretching by external force were compared. The elevated phosphorylation levels of several proteins during the early phase of cell attachment and spreading of fibroblast cell lines were not affected by inhibition of ROCK and myosin II activity, i.e. the reactions occurred independently of intracellular contractile force acting on the adhesion sites. The contraction-independent phosphorylation sites included ERK1/2 T202/Y204, AKT S473, p130CAS Y410, and cofilin S3. In contrast to cell attachment, cyclic stretching of the adherent cells induced a robust phosphorylation only of ERK1/2 and the phosphorylation levels of the other investigated proteins were not or only moderately affected by stretching. No major differences between signaling via ?5?1 or ?v?3 integrins were detected. The importance of mitochondrial ROS for the integrin-induced signaling pathways was investigated using rotenone, a specific inhibitor of complex I in the respiratory chain. While rotenone only moderately reduced ATP levels and hardly affected the signals induced by cyclic cell stretching, it abolished the activation of AKT and reduced the actin polymerization rate in response to attachment in both cell lines. In contrast, scavenging of extracellular ROS with catalase or the vitamin C analog Asc-2P did not significantly influence the attachment-derived signaling, but caused a selective and pronounced enhancement of ERK1/2 phosphorylation in response to stretching. In conclusion, the results showed that "integrin signals" are composed of separate sets of reactions triggered by different types of integrin stimulation. Mitochondrial ROS and extracellular ROS had specific and distinct effects on the integrin signals induced by cell attachment and mechanical stretching. PMID:23738008

Zeller, Kathrin S; Riaz, Anjum; Sarve, Hamid; Li, Jia; Tengholm, Anders; Johansson, Staffan

2013-05-30

334

The role of mechanical force and ROS in integrin-dependent signals.  

UK PubMed Central (United Kingdom)

Cells are exposed to several types of integrin stimuli, which generate responses generally referred to as "integrin signals", but the specific responses to different integrin stimuli are poorly defined. In this study, signals induced by integrin ligation during cell attachment, mechanical force from intracellular contraction, or cell stretching by external force were compared. The elevated phosphorylation levels of several proteins during the early phase of cell attachment and spreading of fibroblast cell lines were not affected by inhibition of ROCK and myosin II activity, i.e. the reactions occurred independently of intracellular contractile force acting on the adhesion sites. The contraction-independent phosphorylation sites included ERK1/2 T202/Y204, AKT S473, p130CAS Y410, and cofilin S3. In contrast to cell attachment, cyclic stretching of the adherent cells induced a robust phosphorylation only of ERK1/2 and the phosphorylation levels of the other investigated proteins were not or only moderately affected by stretching. No major differences between signaling via ?5?1 or ?v?3 integrins were detected. The importance of mitochondrial ROS for the integrin-induced signaling pathways was investigated using rotenone, a specific inhibitor of complex I in the respiratory chain. While rotenone only moderately reduced ATP levels and hardly affected the signals induced by cyclic cell stretching, it abolished the activation of AKT and reduced the actin polymerization rate in response to attachment in both cell lines. In contrast, scavenging of extracellular ROS with catalase or the vitamin C analog Asc-2P did not significantly influence the attachment-derived signaling, but caused a selective and pronounced enhancement of ERK1/2 phosphorylation in response to stretching. In conclusion, the results showed that "integrin signals" are composed of separate sets of reactions triggered by different types of integrin stimulation. Mitochondrial ROS and extracellular ROS had specific and distinct effects on the integrin signals induced by cell attachment and mechanical stretching.

Zeller KS; Riaz A; Sarve H; Li J; Tengholm A; Johansson S

2013-01-01

335

Discussion: 'Congenital hypogonadisms impair quality of life and sexual function,' by Ros et al.  

UK PubMed Central (United Kingdom)

In the roundtable that follows, clinicians discuss a study published in this issue of the Journal in light of its methodology, relevance to practice, and implications for future research. Article discussed: Ros C, Alobid I, Balasch J, et al. Turner's syndrome and other forms of congenital hypogonadism impair quality of life and sexual function. Am J Obstet Gynecol 2013;208:484.e1-6.

Robbins CC; Wolfe M; Squires K; Jungheim E; Weiner L

2013-06-01

336

Hematopoietic stem cell regeneration enhanced by ectopic expression of ROS-detoxifying enzymes in transplant mice.  

UK PubMed Central (United Kingdom)

High levels of reactive oxygen species (ROS) can exhaust hematopoietic stem cells (HSCs). Thus, maintaining a low state of redox in HSCs by modulating ROS-detoxifying enzymes may augment the regeneration potential of HSCs. Our results show that basal expression of manganese superoxide dismutase (MnSOD) and catalase were at low levels in long-term and short-term repopulating HSCs, and administration of a MnSOD plasmid and lipofectin complex (MnSOD-PL) conferred radiation protection on irradiated recipient mice. To assess the intrinsic role of elevated MnSOD or catalase in HSCs and hematopoietic progenitor cells, the MnSOD or catalase gene was overexpressed in mouse hematopoietic cells via retroviral transduction. The impact of MnSOD and catalase on hematopoietic progenitor cells was mild, as measured by colony-forming units (CFUs). However, overexpressed catalase had a significant beneficial effect on long-term engraftment of transplanted HSCs, and this effect was further enhanced after an insult of low-dose ?-irradiation in the transplant mice. In contrast, overexpressed MnSOD exhibited an insignificant effect on long-term engraftment of transplanted HSCs, but had a significant beneficial effect after an insult of sublethal irradiation. Taken together, these results demonstrate that HSC function can be enhanced by ectopic expression of ROS-detoxifying enzymes, especially after radiation exposure in vivo.

Miao W; Xufeng R; Park MR; Gu H; Hu L; Kang JW; Ma S; Liang PH; Li Y; Cheng H; Yu H; Epperly M; Greenberger J; Cheng T

2013-02-01

337

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

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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; Ratna Prabha Chivukula

2010-01-01

338

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

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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.

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

2007-01-01

339

Magnaporthe oryzae cell wall hydrolysate induces ROS and fungistatic VOCs in rice cell cultures.  

UK PubMed Central (United Kingdom)

Plants react to microbial attack with a number of defense mechanisms, including the synthesis of volatile organic compounds (VOCs) and the production of reactive oxygen species (ROS). These responses are triggered by elicitors derived from either the cell surface of pathogens or the incomplete hydrolysis of the plant cell wall. Here we show the response of rice (Oryza sativa L., cv Gigante Vercelli) cell cultures following treatment with cell wall hydrolysates prepared from the rice blast Magnaporthe oryzae. Elicitation prompted the production of several plant VOCs, which were analyzed by stir bar sorptive extraction from both the liquid and head-space phase (SBSE and HSSE, respectively) and gas chromatography coupled to mass spectrometry (GC-MS) analysis. VOCs included alkanes, alkenes and long-chain alcohols as well as cinnamyl alcohol, myristicin, a sesquiterpene alcohol (caryolan-1-ol), 1-butanamide and 2-pentylfuran. The major released compounds, 1-octanol and 1-decanol, were found to induce ROS production in both elicited and non-elicited rice cells and showed fungistatic activity against the pathogen M. oryzae. The possible role of induced VOCs and ROS production in the plant-pathogen interaction is discussed.

Forlani G; Occhipinti A; Bossi S; Bertea CM; Varese C; Maffei ME

2011-11-01

340

Magnaporthe oryzae cell wall hydrolysate induces ROS and fungistatic VOCs in rice cell cultures.  

Science.gov (United States)

Plants react to microbial attack with a number of defense mechanisms, including the synthesis of volatile organic compounds (VOCs) and the production of reactive oxygen species (ROS). These responses are triggered by elicitors derived from either the cell surface of pathogens or the incomplete hydrolysis of the plant cell wall. Here we show the response of rice (Oryza sativa L., cv Gigante Vercelli) cell cultures following treatment with cell wall hydrolysates prepared from the rice blast Magnaporthe oryzae. Elicitation prompted the production of several plant VOCs, which were analyzed by stir bar sorptive extraction from both the liquid and head-space phase (SBSE and HSSE, respectively) and gas chromatography coupled to mass spectrometry (GC-MS) analysis. VOCs included alkanes, alkenes and long-chain alcohols as well as cinnamyl alcohol, myristicin, a sesquiterpene alcohol (caryolan-1-ol), 1-butanamide and 2-pentylfuran. The major released compounds, 1-octanol and 1-decanol, were found to induce ROS production in both elicited and non-elicited rice cells and showed fungistatic activity against the pathogen M. oryzae. The possible role of induced VOCs and ROS production in the plant-pathogen interaction is discussed. PMID:21831477

Forlani, Giuseppe; Occhipinti, Andrea; Bossi, Simone; Bertea, Cinzia M; Varese, Cristina; Maffei, Massimo E

2011-08-09

 
 
 
 
341

Identification of ROS produced by photodynamic activity of chlorophyll/cyclodextrin inclusion complexes.  

UK PubMed Central (United Kingdom)

Photodynamic therapy (PDT) is a way of treating malignant tumors and hyperproliferative diseases. It is based on the use of photosensitizer, herein the chlorophyll a (chl a), and a light of an appropriate wavelength. The interaction of the photosensitizer (PS) with the light produces reactive oxygen species (ROS), powerful oxidizing agents, which cause critical damage to the tissue. To solubilize chl a in aqueous solution and to obtain it as monomer, we have used cyclodextrins, carriers which are able to interact with the pigment and form the inclusion complex. The aim of this study is to examine which types of ROS are formed by Chl a/cyclodextrin complexes in phosphate buffered solution and cell culture medium, using specific molecules, called primary acceptors, which react selectively with the reactive species. In fact the changes of the absorption and the emission spectra of these molecules after the illumination of the PS provide information on the specific ROS formation. The (1) O2 formation has been tested using chemical methods based on the use of Uric Acid (UA), 9,10-diphenilanthracene (DPA) and Singlet oxygen sensor green (SOSG) and by direct detection of Singlet Oxygen ((1) O2 ) luminescence decay at 1270 nm. Moreover, 2,7-dichlorofluorescin and ferricytochrome c (Cyt Fe(3+) ) have been used to detect the formation of hydrogen peroxide and superoxide radical anion, which reduces Fe(3+) of the ferricytochrome to Fe(2+) , respectively.

Cellamare BM; Fini P; Agostiano A; Sortino S; Cosma P

2013-03-01

342

The beetroot component betanin modulates ROS production, DNA damage and apoptosis in human polymorphonuclear neutrophils.  

UK PubMed Central (United Kingdom)

The aim of this study was to evaluate the effect of betanin, one of the beetroot major components, on ROS production, DNA damage and apoptosis in human resting and stimulated with phorbol 12-myristate13-acetate polymorphonuclear neutrophils, one of the key elements of the inflammatory response. Incubation of neutrophils with betanin in the concentration range 2-500?µM resulted in significant inhibition of ROS production (by 15-46%, depending on the ROS detection assay). The antioxidant capacity of betanin was most prominently expressed in the chemiluminescence measurements. This compound decreased also the percentage of DNA in comet tails in stimulated neutrophils, but only at the 24?h time point. In resting neutrophils an increased level of DNA in comet tails was observed. Betanin did not affect the activity of caspase-3, in resting neutrophils, but significantly enhanced the enzyme activity in stimulated neutrophils. The western blot analysis showed, however, an increased level of caspase-3 cleavage products as a result of betanin treatment both in resting and stimulated neutrophils. The results indicate that betanin may be responsible for the effect of beetroot products on neutrophil oxidative metabolism and its consequences, DNA damage and apoptosis. The dose and time dependent effects on these processes require further studies.

Zieli?ska-Przyjemska M; Olejnik A; Kostrzewa A; ?uczak M; Jagodzi?ski PP; Baer-Dubowska W

2012-06-01

343

Global Architectural Forms in the Context of Vilnius Globalios architekt?ros pavidalai Vilniaus kontekste  

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Full Text Available Manifestations of global architecture in the city of Vilnius are analysed on the example of Guggenheim Hermitage Museum. Peculiarities of the architecture’s origin are discussed. Global architecture is different from local architecture by preconditions of its origin, possibilities of realisation and its architectural expression. However, irrespective of these circum­stances Lithuanian creative societies and individual architects evaluate global architecture from local positions. They use conceptions and metaphors formed in the local environment. Therefore, evaluations assume a negative connotation.Article in LithuanianAnalizuojamos globalios architekt?ros apraiškos Vilniaus mieste Gugenheimo Ermitažo muziejaus pavyzdžiu. Aptariami architekt?ros atsiradimo ypatumai. Globali architekt?ra skiriasi nuo lokalios architekt?ros savo atsiradimo prielaidomis, realizavimo galimyb?mis ir savo architekt?rine išraiška. Ta?iau, nepaisant ši? aplinkybi?, Lietuvos k?rybin?s s?jungos ir pavieniai k?r?jai vertina globali? architekt?r? iš lokali? pozicij?. Jie naudoja sampratas ir metaforas, susiformavusias lokalioje aplinkoje. Tod?l vertinimai ?gauna neigiam? konotacij?.Straipsnis lietuvi? kalba

Romualdas Ku?inskas

2009-01-01

344

Curcumin inhibits LPS-induced inflammation in rat vascular smooth muscle cells in vitro via ROS-relative TLR4-MAPK/NF-?B pathways.  

UK PubMed Central (United Kingdom)

AIM: To investigate whether curcumin (Cur) suppressed lipopolysaccharide (LPS)-induced inflammation in vascular smooth muscle cells (VSMCs) of rats, and to determine its molecular mechanisms. METHODS: Primary rat VSMCs were treated with LPS (1 ?g/L) and Cur (5, 10, or 30 ?mol/L) for 24 h. The levels of MCP-1, TNF-?, and iNOS were measured using ELISA and real-time RT-PCR. NO level was analyzed with the Griess reaction. Western-blotting was used to detect the activation of TLR4, MAPKs, I?B?, NF-?B p65, and the p47(phox) subunit of NADPH oxidase in the cells. RESULTS: Treatment of VSMCs with LPS dramatically increased expression of inflammatory cytokines MCP-1 and TNF-?, expression of TLR4 and iNOS, and NO production. LPS also significantly increased phosphorylation of I?B?, nuclear translocation of NF-?B (p65) and phosphorylation of MAPKs in VSMCs. Furthermore, LPS significantly increased production of intracellular ROS, and decreased expression of p47(phox) subunit of NADPH oxidase. Pretreatment with Cur concentration-dependently attenuated all the aberrant changes in LPS-treated VSMCs. The LPS-induced overexpression of MCP-1 and TNF-?, and NO production were attenuated by pretreatment with the ERK inhibitor PD98059, the p38 MAPK inhibitor SB203580, the NF-?B inhibitor PDTC or anti-TLR4 antibody, but not with the JNK inhibitor SP600125. CONCLUSION: Cur suppresses LPS-induced overexpression of inflammatory mediators in VSMCs in vitro via inhibiting the TLR4-MAPK/NF-?B pathways, partly due to block of NADPH-mediated intracellular ROS production.

Meng Z; Yan C; Deng Q; Gao DF; Niu XL

2013-07-01

345

Yuwen02f1 suppresses LPS-induced endotoxemia and adjuvant-induced arthritis primarily through blockade of ROS formation, NFkB and MAPK activation.  

Science.gov (United States)

Phagocytes release inflammatory mediators to defense harmful stimuli upon bacterial invasion, however, excessive inflammatory reaction leads to tissue damage and manifestation of pathological states. Therefore, targeting on uncontrolled inflammation seems feasible to control numerous inflammation-associated diseases. Under the drug screening process of synthetic diphenylpyrazole derivatives, we discovered compound yuwen02f1 possesses anti-inflammatory effects in decreasing the release of pro-inflammatory cytokines including TNF? and IL-6, nitric oxide, reactive oxygen species (ROS) as well as inhibiting migration of LPS-stimulated phagocytes. In addition, we observed that the molecular mechanism of yuwen02f1-mediated anti-inflammation is associated with decreasing phosphorylation of MAPK molecules including ERK1/2, JNK and p38, and attenuating translocation of p47(phox) and p67(phox) to the cell membrane. Yuwen02f1 also reverses I?B? degradation and attenuates the expression of NF?B-related downstream inducible enzymes like iNOS and COX-2. Furthermore, we found that yuwen02f1 attenuates some pathological syndromes of LPS-induced sepsis and adjuvant-induced arthritis in mice, as evidenced by decreasing the cytokine production, reversing thrombocytopenic syndrome, protecting the mice from tissue injury in septic mice, and attenuating paw edema in arthritic mice as well. These results suggest that yuwen02f1 is a potential anti-inflammatory agent for alleviating syndromes of acute and chronic inflammatory diseases as evidenced by attenuating the generation of cytokines and down-regulating the expression of iNOS and COX-2 through the blockade of ROS generation and NADPH oxidase, NF?B and MAPK activation pathways in LPS-stimulated phagocytes. PMID:23142712

Hsu, Chun-Chieh; Lien, Jin-Cherng; Chang, Chia-Wen; Chang, Chien-Hsin; Kuo, Sheng-Chu; Huang, Tur-Fu

2012-11-09

346

Yuwen02f1 suppresses LPS-induced endotoxemia and adjuvant-induced arthritis primarily through blockade of ROS formation, NFkB and MAPK activation.  

UK PubMed Central (United Kingdom)

Phagocytes release inflammatory mediators to defense harmful stimuli upon bacterial invasion, however, excessive inflammatory reaction leads to tissue damage and manifestation of pathological states. Therefore, targeting on uncontrolled inflammation seems feasible to control numerous inflammation-associated diseases. Under the drug screening process of synthetic diphenylpyrazole derivatives, we discovered compound yuwen02f1 possesses anti-inflammatory effects in decreasing the release of pro-inflammatory cytokines including TNF? and IL-6, nitric oxide, reactive oxygen species (ROS) as well as inhibiting migration of LPS-stimulated phagocytes. In addition, we observed that the molecular mechanism of yuwen02f1-mediated anti-inflammation is associated with decreasing phosphorylation of MAPK molecules including ERK1/2, JNK and p38, and attenuating translocation of p47(phox) and p67(phox) to the cell membrane. Yuwen02f1 also reverses I?B? degradation and attenuates the expression of NF?B-related downstream inducible enzymes like iNOS and COX-2. Furthermore, we found that yuwen02f1 attenuates some pathological syndromes of LPS-induced sepsis and adjuvant-induced arthritis in mice, as evidenced by decreasing the cytokine production, reversing thrombocytopenic syndrome, protecting the mice from tissue injury in septic mice, and attenuating paw edema in arthritic mice as well. These results suggest that yuwen02f1 is a potential anti-inflammatory agent for alleviating syndromes of acute and chronic inflammatory diseases as evidenced by attenuating the generation of cytokines and down-regulating the expression of iNOS and COX-2 through the blockade of ROS generation and NADPH oxidase, NF?B and MAPK activation pathways in LPS-stimulated phagocytes.

Hsu CC; Lien JC; Chang CW; Chang CH; Kuo SC; Huang TF

2013-02-01

347

ROS1 receptor tyrosine kinase, a druggable target, is frequently overexpressed in non-small cell lung carcinomas via genetic and epigenetic mechanisms.  

UK PubMed Central (United Kingdom)

BACKGROUND: Microarray analyses have revealed significantly elevated expression of the proto-oncogene ROS1 receptor tyrosine kinase in 20-30% of non-small cell lung carcinomas (NSCLC). Selective and potent ROS1 kinase inhibitors have recently been developed and oncogenic rearrangement of ROS1 in NSCLC identified. METHODS: We performed immunohistochemical evaluation of expression of ROS1 kinase and its downstream molecules in 399 NSCLC cases. ROS1 expression in primary and recurring lesions of 92 recurrent NSCLC cases was additionally analyzed. To elucidate mechanism of expression, two ROS1-nonexpressing NSCLC cell lines (Calu6 and H358) and fresh frozen tissues from 28 consecutive NSCLC patients were examined for ROS1 promoter methylation status and ROS1 expression. RESULTS: Overall expression rate of ROS1 was 22% (19% for adenocarcinomas and 25% for nonadenocarcinomas) in NSCLC. ROS1 expression was a worse prognostic factor for overall survival in adenocarcinomas of stage I NSCLC. In recurred NSCLC, ROS1 expression was significantly higher in recurring tumors (38%) than primary tumors (19%). Two NSCLC cell lines showed increased ROS1 expression after treatment with 5-aza-2'deoxycytidine and/or trichostatin A. Among the 14 adenocarcinomas examined, two (14%) showed more than twice the level of ROS1 expression in tumor tissue than was observed in matched normal tissue and statistically significant differences in the ROS1 promoter methylation level. CONCLUSIONS: A subset of NSCLC revealed overexpression of ROS1 receptor tyrosine kinase, possibly in relation to epigenetic changes. ROS1 expression was an independent prognostic factor for overall survival in adenocarcinomas of stage I NSCLC. Further studies are needed to validate our results.

Lee HJ; Seol HS; Kim JY; Chun SM; Suh YA; Park YS; Kim SW; Choi CM; Park SI; Kim DK; Kim YH; Jang SJ

2013-01-01

348

Thrombin, a mediator of cerebrovascular inflammation in AD and hypoxia.  

UK PubMed Central (United Kingdom)

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 weeks 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 ROS levels in brain and reduces cerebrovascular expression of inflammatory proteins. 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.

Tripathy D; Sanchez A; Yin X; Luo J; Martinez J; Grammas P

2013-01-01

349

Thrombin, a mediator of cerebrovascular inflammation in AD and hypoxia  

Science.gov (United States)

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 weeks 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 ROS levels in brain and reduces cerebrovascular expression of inflammatory proteins. 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.

Tripathy, Debjani; Sanchez, Alma; Yin, Xiangling; Luo, Jinhua; Martinez, Joseph; Grammas, Paula

2013-01-01

350

Murine colitis is mediated by vimentin.  

UK PubMed Central (United Kingdom)

Vimentin, an abundant intermediate filament protein, presumably has an important role in stabilizing intracellular architecture, but its function is otherwise poorly understood. In a vimentin knockout (Vim KO) mouse model, we note that Vim KO mice challenged with intraperitoneal Escherichia coli control bacterial infection better than do wild-type (WT) mice. In vitro, Vim KO phagocytes show significantly increased capacity to mediate bacterial killing by abundant production of reactive oxygen species (ROS) and nitric oxides, likely due to interactions with the p47phox active subunit of NADPH oxidase. In acute colitis induced by dextran sodium sulfate (DSS), Vim KO mice develop significantly less gut inflammation than do WT mice. Further, Vim KO mice have markedly decreased bacterial extravasation in the setting of DSS-induced acute colitis, consistent with decreased intestinal disease. Our results suggest that vimentin impedes bacterial killing and production of ROS, thereby contributing to the pathogenesis of acute colitis.

Mor-Vaknin N; Legendre M; Yu Y; Serezani CH; Garg SK; Jatzek A; Swanson MD; Gonzalez-Hernandez MJ; Teitz-Tennenbaum S; Punturieri A; Engleberg NC; Banerjee R; Peters-Golden M; Kao JY; Markovitz DM

2013-01-01

351

Inhibition of ROS-activated ERK1/2 pathway contributes to the protection of H2S against chemical hypoxia-induced injury in H9c2 cells.  

UK PubMed Central (United Kingdom)

Hydrogen sulfide (H(2)S) has been shown to exert cardioprotective effects. However, the roles of extracellular signal-regulated protein kinases 1/2 (ERK1/2) in H(2)S-induced cardioprotection have not been completely elucidated. In this study, cobalt chloride (CoCl(2)), a chemical hypoxia mimetic agent, was applied to treat H9c2 cells to establish a chemical hypoxia-induced cardiomyocyte injury model. The results showed that pretreatment with NaHS (a donor of H(2)S) before exposure to CoCl(2) attenuated the decreased cell viability, the increased apoptosis rate, the loss of mitochondrial membrane potential (??m), and the intracellular accumulation of reactive oxygen species (ROS) in H9c2 cells. Exposure of H9c2 cells to CoCl(2) or hydrogen peroxide (H(2)O(2)) upregulated expression of phosphorylated (p) ERK1/2, which was reduced by pretreatment with NaHS or N-acetyl-L-cysteine, a ROS scavenger. More importantly, U0126, a selective inhibitor of ERK1/2, mimicked the above cytoprotection of H(2)S against CoCl(2)-induced injury in H9c2 cells. In conclusion, these results indicate that H(2)S protects H9c2 cells against chemical hypoxia-induced injury partially by inhibiting ROS-mediated activation of ERK1/2.

Dong XB; Yang CT; Zheng DD; Mo LQ; Wang XY; Lan AP; Hu F; Chen PX; Feng JQ; Zhang MF; Liao XX

2012-03-01

352

Sensitivity of malignant peripheral nerve sheath tumor cells to TRAIL is augmented by loss of NF1 through modulation of MYC/MAD and is potentiated by curcumin through induction of ROS.  

UK PubMed Central (United Kingdom)

Malignant peripheral nerve sheath tumor (MPNST) is a rare aggressive form of sarcoma often associated with the tumor syndrome neurofibromatosis type 1 (NF1). We investigated the effects of tumor necrosis factor-related apoptosis inducing ligand (TRAIL) on NF1 associated MPNST and determinants of TRAIL sensitivity. MPNST cell lines with complete neurofibromin deficiency were sensitive to apoptotic cell death induced by TRAIL whereas MPNST cells with retained neurofibromin expression or normal human Schwann cells were resistant. Increased sensitivity to TRAIL was associated with overexpression of death receptors, especially DR5. Re-expression of the GAP related domain of neurofibromin (NF1-GRD) suppressed DR5 expression and decreased sensitivity to TRAIL. We show that death receptor expression and TRAIL sensitivity critically depend on c-MYC and that c-MYC amounts are increased by MEK/ERK and PI3K/AKT signalling pathways which are suppressed by neurofibromin. Furthermore PI3K/AKT signalling strongly suppresses the MYC-antagonist MAD1 which significantly contributes to TRAIL sensitivity. Re-expression of the NF1-GRD decreas