Search results for "REACTIVE OXYGEN SPECIES"
showing 10 items of 879 documents
Isoindolo[2,1-a]quinoxaline derivatives, novel potent antitumor agents with dual inhibition of tubulin polymerization and topoisomerase I.
2008
Isoindoloquinoxalines 4 and 5 were obtained by refluxing 2-(2'-aminoaryl)-1-cyanoisoindoles 3a- e in acetic or formic acid. All derivatives were screened by the National Cancer Institute (Bethesda, MD) for the in vitro one dose primary anticancer assay against a 3-cell line panel. Compounds 4a- e, screened against a panel of about 60 human tumor cell lines, showed remarkable antineoplastic activity; they had GI 50 values in the low micromolar or submicromolar range and reached, in the case of 4c, nanomolar concentrations on 88% of the 59 tested cell lines. Flow cytometric analysis of cell cycle after treatment with 4c demonstrated an arrest of the cell cycle in G2/M phase. This effect was a…
Comparison of Protective Effects against Reactive Oxygen Species of Mononuclear and Dinuclear Cu(II) Complexes with N-Substituted Benzothiazolesulfon…
2005
Copper(II) complexes of N-benzothiazolesulfonamides (HL1=N-2-(4-methylphenylsulfamoyl)-6-nitro-benzothiazole, HL2=N-2-(phenylsulfamoyl)-6-chloro-benzothiazole, and HL3=N-2-(4-methylphenylsulfamoyl)-6-chloro-benzothiazole) with ammonia have been synthesized and characterized. The crystal structures of the [Cu(L1)2(NH3)2].2MeOH, [Cu(L2)2(NH3)2], and [Cu(L3)2(NH3)2] compounds have been determined. Compounds and present a distorted square planar geometry. In both compounds the metal ion is coordinated by two benzothiazole N atoms from two sulfonamidate anions and two NH3 molecules. Complex is distorted square-pyramidal. The Cu(II) ion is linked to the benzothiazole N and sulfonamidate O atoms o…
Characterization and metal-induced gene transcription of two new copper zinc superoxide dismutases in the solitary ascidian Ciona intestinalis
2013
Antioxidant enzymes are known to protect living organisms against the oxidative stress risk, also induced by metals. In the present study, we describe the purification and molecular characterization of two Cu,Zn superoxide dismutases (SODs), referred to as Ci-SODa and Ci-SODb, from Ciona intestinalis, a basal chordate widely distributed in temperate shallow seawater. The putative amino acid sequences were compared with Cu,Zn SODs from other metazoans and phylogenetic analyses indicate that the two putative Ci-SODs are more related to invertebrate SODs than vertebrate ones. Both phylogenetic and preliminary homology modeling analyses suggest that Ci-SODa and Ci-SODb are extracellular and int…
Preparation of two sets of 5,6,7-trioxygenated dihydroflavonol derivatives as free radical scavengers and neuronal cell protectors to oxidative damag…
2009
An unusual class of 5,6,7-trioxygenated dihydroflavonols (3a-e and 4a-j) were designed and prepared. Their antioxidative properties were assessed by examining their capacities in several in vitro models, including superoxide anion and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, rat liver homogenate lipid peroxidation inhibition, PC12 cells protection from oxidative damage, and xanthine oxidase inhibition. These dihydroflavonols displayed positive quenching abilities towards O(2)(-) and DPPH free radicals, in which the majority exhibited superior antioxidant properties to Vitamin C. cis-Configurated compound (+/-)-3e demonstrated remarkable inhibition to LPO with an IC(50) value…
Oxidative stress upregulates the NMDA receptor on cerebrovascular endothelium.
2009
N-methyl-d-aspartate receptor (NMDA-R)-mediated oxidative stress has been implicated in blood-brain barrier (BBB) disruption in a variety of neuropathological diseases. Although some interactions between both phenomena have been elucidated, possible influences of reactive oxygen species (ROS) on the NMDA-R itself have so far been neglected. The objective of this study was to examine how the cerebroendothelial NMDA-R is affected by exposure to oxidative stress and to assess possible influences on BBB integrity. RT-PCR confirmed several NMDA-R subunits (NR1, NR2B-D) expressed in the bEnd3 cell line (murine cerebrovascular endothelial cells). NR1 protein expression after exposure to ROS was ob…
β-Aminobutyric Acid Primes an NADPH Oxidase–Dependent Reactive Oxygen Species Production During Grapevine-Triggered Immunity
2010
International audience; The molecular mechanisms underlying the process of priming are poorly understood. In the present study, we investigated the early signaling events triggered by β-aminobutyric acid (BABA), a well-known priming-mediated plant resistance inducer. Our results indicate that, in contrast to oligogalacturonides (OG), BABA does not elicit typical defense-related early signaling events nor defense-gene expression in grapevine. However, in OG-elicited cells pretreated with BABA, production of reactive oxygen species (ROS) and expression of the respiratory-burst oxidase homolog RbohD gene were primed. In response to the causal agent of downy mildew Plasmopara viticola, a strong…
Loss of Nrf2 in bone marrow-derived macrophages impairs antigen-driven CD8+ T cell function by limiting GSH and Cys availability
2015
NF-E2-related factor 2 (Nrf2), known to protect against reactive oxygen species, has recently been reported to resolve acute inflammatory responses in activated macrophages. Consequently, disruption of Nrf2 promotes a proinflammatory macrophage phenotype. In the current study, we addressed the impact of this macrophage phenotype on CD8(+) T cell activation by using an antigen-driven coculture model consisting of Nrf2(-/-) and Nrf2(+/+) bone marrow-derived macrophages (BMDMΦ) and transgenic OT-1 CD8(+) T cells. OT-1 CD8(+) T cells encode a T cell receptor that specifically recognizes MHC class I-presented ovalbumin OVA(257-264) peptide, thereby causing a downstream T cell activation. Interes…
Redox signaling in acute pancreatitis
2015
Acute pancreatitis is an inflammatory process of the pancreatic gland that eventually may lead to a severe systemic inflammatory response. A key event in pancreatic damage is the intracellular activation of NF-κB and zymogens, involving also calcium, cathepsins, pH disorders, autophagy, and cell death, particularly necrosis. This review focuses on the new role of redox signaling in acute pancreatitis. Oxidative stress and redox status are involved in the onset of acute pancreatitis and also in the development of the systemic inflammatory response, being glutathione depletion, xanthine oxidase activation, and thiol oxidation in proteins critical features of the disease in the pancreas. On th…
The role of oxidative stress in pro-inflammatory activation of human endothelial cells on Ti6Al4V alloy
2013
Inflammation is an important step in the early phase of tissue regeneration around an implanted metallic orthopaedic device. However, prolonged inflammation, which can be induced by metallic corrosion products, can lead to aseptic loosening and implant failure. Cells in peri-implant tissue as well as metal corrosion can induce reactive oxygen species (ROS) formation, thus contributing to an oxidative microenvironment around an implant. Understanding cellular reactions to implant-induced oxidative stress and inflammatory activation is important to help prevent an adverse response to metallic materials. In an earlier study we have shown that endothelial cells grown on Ti6Al4V alloy are subjec…
Reactive oxygen species induced by beauvericin, patulin and zearalenone in CHO-K1 cells
2008
The cytotoxic effects of mycotoxins, induction of reactive oxygen species (ROS) and generation of lipid peroxidation products in CHO-K1 cells were determined as function of increasing time of exposure and concentrations of beauvericin (BEA), patulin (PAT) and zearalenone (ZEA). The end points were evaluated after 24h of exposure, by the tetrazolium salt (MTT) and neutral red (NR) assays. The IC(50) values obtained on the MTT and NR assays ranged from 0.69 to 79.40 microM and 4.40 to 108.76 microM, respectively. To determine the intracellular production of ROS, the intensity of fluorescence emitted from the probe H(2)-DCFDA was measured. The relative intensity of fluorescence from cells incu…