In laboratory experiments, many electrophilic cytotoxic agents induce cell death accompanied by reactive oxygen species (ROS) production and/or by glutathione (GSH) depletion. Not surprisingly, millimolar concentrations of N-acetylcysteine (NAC), which is used as a universal ROS scavenger and precursor of GSH biosynthesis, inhibit ROS production, restore GSH levels, and prevent cell death. The protective effect of NAC is generally used as corroborative evidence that cell death induced by a studied cytotoxic agent is mediated by an oxidative stress-related mechanism. However, any simple interpretation of the results of the protective effects of NAC may be misleading because it is unable to interact with superoxide (O2•-), the most important biologically relevant ROS, and is a very weak scavenger of H2O2. In addition, NAC is used in concentrations that are unnecessarily high to stimulate GSH synthesis. Unfortunately, the possibility that NAC as a nucleophile can directly interact with cytotoxic electrophiles to form non-cytotoxic NAC-electrophile adduct is rarely considered, although it is a well-known protective mechanism that is much more common than expected. Overall, apropos the possible mechanism of the cytoprotective effect of NAC in vitro, it is appropriate to investigate whether there is a direct interaction between NAC and the cytotoxic electrophile to form a non-cytotoxic NAC-electrophilic adduct(s).

• Klíčová slova
• N-acetylcysteine, N-acetylcysteine-electrophile adduct, electrophile, mechanism of protection, nucleophile,
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

N-acetylcysteine (NAC), often used as an antioxidant-scavenging reactive oxygen species (ROS) in vitro, was recently shown to increase the cytotoxicity of other compounds through ROS-dependent and ROS-independent mechanisms. In this study, NAC itself was found to induce extensive ROS production in human leukemia HL-60 and U937 cells. The cytotoxicity depends on ROS-modulating enzyme expression. In HL-60 cells, NAC activated NOX2 to produce superoxide (O2•-). Its subsequent conversion into H2O2 by superoxide dismutase 1 and 3 (SOD1, SOD3) and production of ClO- from H2O2 by myeloperoxidase (MPO) was necessary for cell death induction. While the addition of extracellular SOD potentiated NAC-induced cell death, extracellular catalase (CAT) prevented cell death in HL-60 cells. The MPO inhibitor partially reduced the number of dying HL-60 cells. In U937 cells, the weak cytotoxicity of NAC is probably caused by lower expression of NOX2, SOD1, SOD3, and by the absence of MOP expression. However, even here, the addition of extracellular SOD induced cell death in U937 cells, and this effect could be reversed by extracellular CAT. NAC-induced cell death exhibited predominantly apoptotic features in both cell lines. Conclusions: NAC itself can induce extensive production of O2•- in HL-60 and U937 cell lines. The fate of the cells then depends on the expression of enzymes that control the formation and conversion of ROS: NOX, SOD, and MPO. The mode of cell death in response to NAC treatment bears apoptotic and apoptotic-like features in both cell lines.

• Klíčová slova
• HL-60 cells, MPO, N-acetylcysteine, NOX, SOD, U937 cells, oxidative stress,
• MeSH
• acetylcystein farmakologie   MeSH
• HL-60 buňky MeSH
• katalasa genetika   MeSH
• leukemie farmakoterapie   genetika   metabolismus   MeSH
• lidé MeSH
• NADPH-oxidasa 2 genetika   MeSH
• oxidační stres účinky léků   MeSH
• peroxidasa genetika   MeSH
• proliferace buněk účinky léků   MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• regulace genové exprese u nádorů účinky léků   MeSH
• stanovení celkové genové exprese MeSH
• superoxiddismutasa genetika   MeSH
• U937 buňky MeSH
• viabilita buněk účinky léků   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• acetylcystein MeSH
• CYBB protein, human MeSH Prohlížeč
• katalasa MeSH
• MPO protein, human MeSH Prohlížeč
• NADPH-oxidasa 2 MeSH
• peroxidasa MeSH
• reaktivní formy kyslíku MeSH
• superoxiddismutasa MeSH

The potential of nanomaterials use is huge, especially in fields such as medicine or industry. Due to widespread use of nanomaterials, their cytotoxicity and involvement in cellular pathways ought to be evaluated in detail. Nanomaterials can induce the production of a number of substances in cells, including reactive oxygen species (ROS), participating in physiological and pathological cellular processes. These highly reactive substances include: superoxide, singlet oxygen, hydroxyl radical, and hydrogen peroxide. For overall assessment, there are a number of fluorescent probes in particular that are very specific and selective for given ROS. In addition, due to the involvement of ROS in a number of cellular signaling pathways, understanding the principle of ROS production induced by nanomaterials is very important. For defense, the cells have a number of reparative and especially antioxidant mechanisms. One of the most potent antioxidants is a tripeptide glutathione. Thus, the glutathione depletion can be a characteristic manifestation of harmful effects caused by the prooxidative-acting of nanomaterials in cells. For these reasons, here we would like to provide a review on the current knowledge of ROS-mediated cellular nanotoxicity manifesting as glutathione depletion, including an overview of approaches for the detection of ROS levels in cells.

• Klíčová slova
• cell injury, fluorescence probes, glutathione, nanotoxicity, oxidative stress, reactive oxygen species,
• MeSH
• buňky účinky léků   metabolismus   MeSH
• glutathion metabolismus   MeSH
• lidé MeSH
• nanostruktury toxicita   MeSH
• oxidační stres účinky léků   MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• signální transdukce účinky léků   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• glutathion MeSH
• reaktivní formy kyslíku MeSH

Dihydromyricetin (DHM) is a natural flavonoid showing several health promoting effects such as protective activity during severe alcohol intoxication. The mechanism underlying the effects of DHM on alcohol metabolism is virtually unknown. The present paper is focused on clarifying the role of DHM in the liver alcohol elimination at its molecular level. First, impact of DHM on alcohol dehydrogenase (ADH) activity in vitro and the enzyme induction in vivo was examined. Neither the ADH activity nor the enzyme expression were influenced by DHM. Next, the effect of DHM during alcohol intoxication were studied on primary hepatocytes isolated from EtOH-premedicated and untreated rats. The viability of cells exposed to alcohol, estimated based on the released enzymes, alanine aminotransferase (ALT) and aspartate aminotransferase (AST), was slightly affected by DHM. Although the expected hepatoprotective effect of DHM was not fully achieved, DHM (in a concentration manner) proved to reduce the level of ROS/RNS in hepatocytes. However, no change in the rate of alcohol metabolism in vivo was found when rats were administered with a single or repeated dose of ethanol supplemented with DHM. In conclusion, the proposed positive effect of DHM during alcohol intoxication has not been proven. Moreover, there is no effect of DHM on the alcohol metabolism. The "hoped-for" DHM hepatoprotective activity can be attributed to the reduction of ROS/RNS levels in cells.

• MeSH
• alkoholdehydrogenasa metabolismus   MeSH
• antioxidancia farmakologie   MeSH
• cytochrom P-450 CYP2E1 metabolismus   MeSH
• ethanol metabolismus   MeSH
• flavonoly farmakologie   MeSH
• hepatocyty účinky léků   metabolismus   MeSH
• játra účinky léků   metabolismus   MeSH
• kultivované buňky MeSH
• metabolická inaktivace MeSH
• nitrosativní stres účinky léků   MeSH
• oxidační stres účinky léků   MeSH
• potkani Wistar MeSH
• reaktivní formy dusíku metabolismus   MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• alkoholdehydrogenasa MeSH
• antioxidancia MeSH
• cytochrom P-450 CYP2E1 MeSH
• dihydromyricetin MeSH Prohlížeč
• ethanol MeSH
• flavonoly MeSH
• reaktivní formy dusíku MeSH
• reaktivní formy kyslíku MeSH

We recently developed a new light source that allows for the continuous monitoring of light-induced changes using common spectrophotometric devices adapted for microplate analyses. This source was designed primarily to induce photodynamic processes in cell models. Modern light components, such as LED chips, were used to improve the irradiance homogeneity. In addition, this source forms a small hermetic chamber and thus allows for the regulation of the surrounding atmosphere, which plays a significant role in these light-dependent reactions. The efficacy of the new light source was proven via kinetic measurements of reactive oxygen species generated during the photodynamic reaction of chloroaluminium phthalocyanine disulfonate (ClAlPcS2) in three cell lines: human melanoma cells (G361), human breast adenocarcinoma cells (MCF7), and human fibroblasts (BJ).

• Klíčová slova
• In vitro, Light source, Microplate reader, Photodynamic effect,
• MeSH
• biologické modely * MeSH
• fibroblasty cytologie   metabolismus   účinky záření   MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• světlo * MeSH
• vysoká teplota MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• reaktivní formy kyslíku MeSH

Low molecular weight mannogalactofucans (LMMGFs) prepared by enzymatic degradation of high molecular weight Undaria galactofucan (MF) were evaluated for their anti-cancer effects against human prostate cancer. Correlation NMR and linkage analyses confirmed that LMMGFs consist mainly of α-fucose and β-galactose units: α-fucose units are 1,3-linked; β-galactose units are terminal, 1,3- and/or 1,6-linked; both sugars are partially sulphated, fucose at positions O-2 and/or O-4 and galactose at O-3. Mannose residue, as a minor sugar, presents as the 1,4-linked terminal units. LMMGFs more significantly induced cell cycle arrest at the G0/G1 phase and cell death via suppression of the Akt/GSK-3β/β-catenin pathway than MF in human PC-3 prostate cancer cells. LMMGFs upregulated mRNA expression of death receptor-5 (DR-5), the ratio of Bax to Bcl-2, the cleavage of caspases and PARP, the depolarisation of mitochondrial membrane potential, and ROS generation. LMMGFs (200-400 mg/kg) effectively reduced both tumour volume and size in a xenografted mouse model. These results demonstrated that LMMGFs attenuate the growth of human prostate cancer cells both in vitro and in vivo, suggesting that LMMGFs can be used as a potent functional ingredient in health-beneficial foods or as a therapeutic agent to prevent or treat androgen-independent human prostate cancer. Graphical Abstract.

• Klíčová slova
• Fucoidan, Low molecular weight mannogalactofucans, Prostate cancer, Undaria pinnatifida,
• MeSH
• apoptóza účinky léků   MeSH
• beta-katenin metabolismus   MeSH
• kinasa glykogensynthasy 3beta metabolismus   MeSH
• kontrolní body buněčného cyklu účinky léků   MeSH
• lidé MeSH
• membránový potenciál mitochondrií účinky léků   MeSH
• messenger RNA genetika   MeSH
• molekulová hmotnost MeSH
• myši MeSH
• nádory prostaty farmakoterapie   metabolismus   MeSH
• polysacharidy chemie   farmakologie   terapeutické užití   MeSH
• Undaria chemie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• beta-katenin MeSH
• fucoidan MeSH Prohlížeč
• kinasa glykogensynthasy 3beta MeSH
• messenger RNA MeSH
• polysacharidy MeSH

Oxidative stress after birth led us to localize reactive oxygen and nitrogen species (RONS) production in the developing rat brain. Brains were assessed a day prenatally and on postnatal days 1, 2, 4, 8, 14, 30, and 60. Oxidation of dihydroethidium detected superoxide; 6-carboxy-2',7'-dichlorodihydrofluorescein diacetate revealed hydrogen peroxide; immunohistochemical proof of nitrotyrosine and carboxyethyllysine detected peroxynitrite formation and lipid peroxidation, respectively. Blue autofluorescence detected protein oxidation. The foetuses showed moderate RONS production, which changed cyclically during further development. The periods and sites of peak production of individual RONS differed, suggesting independent generation. On day 1, neuronal/glial RONS production decreased indicating that increased oxygen concentration after birth did not cause oxidative stress. Dramatic changes in the amount and the sites of RONS production occurred on day 4. Nitrotyrosine detection reached its maximum. Day 14 represented other vast alterations in RONS generation. Superoxide production in arachnoidal membrane reached its peak. From this day on, the internal elastic laminae of blood vessels revealed the blue autofluorescence. The adult animals produced moderate levels of superoxide; all other markers reached their minimum. There was a strong correlation between detection of nitrotyrosine and carboxyethyllysine probably caused by lipid peroxidation initiated with RONS.

• MeSH
• fluorescenční mikroskopie MeSH
• glykosylace MeSH
• kyselina peroxydusitá metabolismus   MeSH
• lysin analogy a deriváty   metabolismus   MeSH
• mozek růst a vývoj   metabolismus   MeSH
• novorozená zvířata MeSH
• oxidační stres * MeSH
• peroxid vodíku metabolismus   MeSH
• peroxidace lipidů MeSH
• posttranslační úpravy proteinů MeSH
• potkani Wistar MeSH
• reaktivní formy dusíku metabolismus   MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• superoxidy metabolismus   MeSH
• tyrosin analogy a deriváty   metabolismus   MeSH
• věkové faktory MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• 3-nitrotyrosine MeSH Prohlížeč
• kyselina peroxydusitá MeSH
• lysin MeSH
• N(6)-carboxyethyllysine MeSH Prohlížeč
• peroxid vodíku MeSH
• reaktivní formy dusíku MeSH
• reaktivní formy kyslíku MeSH
• superoxidy MeSH
• tyrosin MeSH

N(6)-benzyladenine (BA) and N(6)-benzyladenosine ([9R]BA) induce massive production of reactive oxygen species (ROS) that is eventually followed by a loss of cell viability in tobacco BY-2 cells (Mlejnek et al. Plant Cell Environ 26:1723-1735, 2003, Plant Sci 168:389-395, 2005). Results presented in this work suggest that the main sources of ROS are likely mitochondria and that the maintenance of the mitochondrial transmembrane potential is crucial for ROS production in cytokinin-treaded BY-2 cells. Therefore, the possible involvement of alternative oxidase (AOX) in cell death process induced by BA and [9R]BA was studied. About three- to fourfold increase in mRNA levels of AOX1 was observed a few hours after the BA and [9R]BA addition into the growth medium. The elevated expression of AOX1 mRNA could be prevented by adding adenine and adenosine which simultaneously reduced the cytotoxic effects of BA and [9R]BA, respectively. N(6)-benzyladenine 7-β-D-glucoside ([7G]BA) which is a common non-toxic metabolite of BA and [9R]BA did not affect the AOX1 mRNA expression. Although AOX1 seemed to be involved in protection of BY-2 cells against the abiotic stress induced by BA and [9R]BA, the results do not support the idea that it protects cells from death exclusively by scavenging of reactive oxygen species. Indeed, N-propyl gallate, an inhibitor of AOX, decreased cell survival despite it concomitantly decreased the ROS production. This finding is in contrast to the effect of salicylhydroxamic acid, another well-known inhibitor of AOX, which also increased the number of dying cells while it increased the ROS production.

• MeSH
• adenosin analogy a deriváty   farmakologie   MeSH
• benzylové sloučeniny MeSH
• buněčná smrt fyziologie   MeSH
• genetické inženýrství MeSH
• geneticky modifikované rostliny MeSH
• kinetin farmakologie   MeSH
• kultivované buňky MeSH
• messenger RNA biosyntéza   genetika   MeSH
• mitochondrie účinky léků   genetika   metabolismus   MeSH
• oxidoreduktasy biosyntéza   genetika   MeSH
• puriny MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• rostlinné proteiny biosyntéza   genetika   MeSH
• tabák cytologie   účinky léků   genetika   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• adenosin MeSH
• benzylaminopurine MeSH Prohlížeč
• benzylové sloučeniny MeSH
• kinetin MeSH
• messenger RNA MeSH
• N(6)-benzyladenosine MeSH Prohlížeč
• oxidoreduktasy MeSH
• puriny MeSH
• reaktivní formy kyslíku MeSH
• rostlinné proteiny MeSH

Reactive oxygen species (ROS) play several biological roles. We investigated the applicability of fluorescent probes for their detection (i) in rabbit lens epithelial cells during ageing in culture, and (ii) in thin sections of rat heart. We used dihydroethidium (DHE), dichlorofluorescin (DCFH), and dihydrorhodamine 123 (DHR) together with detection of autofluorescence both in cells and in chloroform extracts. Superoxide production was confirmed by a specific histochemical method using Mn(2+). All methods demonstrated higher production of ROS in older cells. All probes revealed different sites of ROS production in young and old cells and could be used for investigation of ROS generation during cell ageing. In the thin sections of rat heart DCFH was not suitable for intracellular ROS detection. The results indicate that the potential of fluorescent dyes in ROS detection is not usually fully exploited, and that blue autofluorescence is associated with oxidative damage.

• MeSH
• epitelové buňky metabolismus   MeSH
• ethidium analogy a deriváty   MeSH
• fluoresceiny MeSH
• králíci MeSH
• krysa rodu Rattus MeSH
• metody MeSH
• molekulární sondy - techniky * MeSH
• myokard metabolismus   MeSH
• oční čočka cytologie   MeSH
• reaktivní formy kyslíku analýza   MeSH
• rhodaminy MeSH
• volné radikály analýza   MeSH
• zvířata MeSH
• Check Tag
• králíci MeSH
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• hodnotící studie MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 2',7'-dichlorofluorescein MeSH Prohlížeč
• dihydroethidium MeSH Prohlížeč
• dihydrorhodamine 123 MeSH Prohlížeč
• ethidium MeSH
• fluoresceiny MeSH
• reaktivní formy kyslíku MeSH
• rhodaminy MeSH
• volné radikály MeSH

Hydrogen peroxide production in yeast cells undergoing programmed cell death in response to acetic acid occurred in the majority of live cells 15 min after death induction and was no longer detectable after 60 min. Superoxide anion production was found later, 60 and 90 min after death induction when cells viability was 60 and 30%, respectively. In cells protected from death due to acid stress adaptation neither hydrogen peroxide nor superoxide anion could be observed after acetic acid treatment. The early production of hydrogen peroxide in cells in which survival was 100% could play a major role in acetic acid-induced programmed cell death signaling. Superoxide anion is assumed to be generated in cells already en route to acetic acid-induced programmed cell death.

• MeSH
• apoptóza fyziologie   MeSH
• katalasa metabolismus   MeSH
• kyselina octová farmakologie   MeSH
• kyseliny farmakologie   MeSH
• peroxid vodíku metabolismus   MeSH
• Saccharomyces cerevisiae enzymologie   fyziologie   MeSH
• superoxiddismutasa metabolismus   MeSH
• superoxidy metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• katalasa MeSH
• kyselina octová MeSH
• kyseliny MeSH
• peroxid vodíku MeSH
• superoxiddismutasa MeSH
• superoxidy MeSH