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1.
Life Sci ; 231: 116572, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31207309

RESUMO

OBJECTIVES: The aim of this study was to investigate whether some of the cephalosporin group antibiotics have inhibition effects on GR and GST enzymes with important functions in the metabolic pathway. METHODS: In this study, some selected cephalosporin group antibiotics on GST and GR enzyme was carried out using 96 rats. 16 groups (16 × 6) were created from these rats, divided to another 4 groups (4 × 24). The resulting groups were named as sham groups, cefazolin groups, cefuroxime groups and cefoperazone groups, respectively. The antibiotics used were injected to cefazolin, cefuroxime and cefoperazone groups. The inhibition effects of the antibiotics were measured in the different time intervals (1st, 3th, 5th, 7th). The statistical investigation of the results was performed using the SPSS software program. RESULTS: Results revealed the complex effects of the tested substances on GR and GST activity at different time intervals and in different tissues (p < 0.05). This indicated that the tested substances could be exposed to different interactions in vivo. CONCLUSION: The tested antibiotics showed some significant inhibition effects on the GST and GR enzyme activity in some tissues of brain, eye and muscle. The interaction of enzyme - the drug is a key factor to highlight the toxicological mechanism. For this reason, the results obtained from in vivo experiments are crucial to explane the physiological properties of the enzymes.


Assuntos
Cefalosporinas/farmacologia , Glutationa Redutase/antagonistas & inibidores , Glutationa Transferase/antagonistas & inibidores , Animais , Antibacterianos/farmacologia , Cefazolina/farmacologia , Cefoperazona/farmacologia , Cefuroxima/farmacologia , Inibidores Enzimáticos/farmacologia , Glutationa/metabolismo , Glutationa Peroxidase/antagonistas & inibidores , Glutationa Peroxidase/metabolismo , Glutationa Redutase/metabolismo , Glutationa Transferase/metabolismo , Ratos
2.
Nat Cell Biol ; 21(5): 579-591, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30962574

RESUMO

It is well established that ferroptosis is primarily controlled by glutathione peroxidase 4 (GPX4). Surprisingly, we observed that p53 activation modulates ferroptotic responses without apparent effects on GPX4 function. Instead, ALOX12 inactivation diminishes p53-mediated ferroptosis induced by reactive oxygen species stress and abrogates p53-dependent inhibition of tumour growth in xenograft models, suggesting that ALOX12 is critical for p53-mediated ferroptosis. The ALOX12 gene resides on human chromosome 17p13.1, a hotspot of monoallelic deletion in human cancers. Loss of one Alox12 allele is sufficient to accelerate tumorigenesis in Eµ-Myc lymphoma models. Moreover, ALOX12 missense mutations from human cancers abrogate its ability to oxygenate polyunsaturated fatty acids and to induce p53-mediated ferroptosis. Notably, ALOX12 is dispensable for ferroptosis induced by erastin or GPX4 inhibitors; conversely, ACSL4 is required for ferroptosis upon GPX4 inhibition but dispensable for p53-mediated ferroptosis. Thus, our study identifies an ALOX12-mediated, ACSL4-independent ferroptosis pathway that is critical for p53-dependent tumour suppression.


Assuntos
Araquidonato 12-Lipoxigenase/genética , Carcinogênese/genética , Glutationa Peroxidase/genética , Proteína Supressora de Tumor p53/genética , Animais , Apoptose/genética , Linhagem Celular Tumoral , Modelos Animais de Doenças , Glutationa Peroxidase/antagonistas & inibidores , Humanos , Peroxidação de Lipídeos/genética , Linfoma/genética , Linfoma/patologia , Camundongos , Mutação de Sentido Incorreto/genética , Espécies Reativas de Oxigênio , Ensaios Antitumorais Modelo de Xenoenxerto
3.
J Food Sci ; 83(5): 1463-1469, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29693723

RESUMO

The content of several phenolic acids and flavonoids in aqueous extract (AE) and ethanol extract (EE) of daylily flower (Hemerocallis fulva L.) was analyzed. The effects of AE or EE at 0.5%, 1%, or 2% in HUVE cells against high glucose-induced cell death, oxidative, and inflammatory damage were examined. Results showed that seven phenolic acids and seven flavonoids could be detected in AE or EE, in the range of 29 to 205 and 41 to 273 mg/100 g, respectively. Compared with the control groups, high glucose raised the activity of caspase-3 and caspase-8; suppressed Bcl-2 mRNA expression and increased Bax mRNA expression; and induced HUVE cells apoptosis. The pretreatments from AE or EE at 1% or 2% reduced caspase-3 activity and Bax mRNA expression, and enhanced cell viability. High glucose decreased glutathione content; stimulated the production of reactive oxygen species, interleukin-6, tumor necrosis factor-alpha, and prostaglandin E2 ; raised the activity of cyclooxygenase-2 and nuclear factor kappa B p50/65 binding; and reduced the activity of glutathione peroxidase, glutathione reductase, and catalase in HUVE cells. AE pretreatments at 1% and 2% reversed these changes. These novel findings suggested that daylily flower was rich in phytochemicals, and could be viewed as a potent functional food against diabetes.


Assuntos
Flores/química , Hemerocallis/química , Extratos Vegetais/farmacologia , Substâncias Protetoras/farmacologia , Antioxidantes/análise , Antioxidantes/farmacologia , Apoptose/efeitos dos fármacos , Caspase 3/metabolismo , Caspase 8/metabolismo , Catalase/antagonistas & inibidores , Catalase/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Ciclo-Oxigenase 2/metabolismo , Dinoprostona/metabolismo , Flavonoides/análise , Flavonoides/farmacologia , Glucose/efeitos adversos , Glutationa Peroxidase/antagonistas & inibidores , Glutationa Peroxidase/metabolismo , Glutationa Redutase/antagonistas & inibidores , Glutationa Redutase/metabolismo , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Humanos , Interleucina-6/metabolismo , NF-kappa B/metabolismo , Extratos Vegetais/análise , Substâncias Protetoras/análise , Espécies Reativas de Oxigênio/metabolismo , Fator de Necrose Tumoral alfa/metabolismo
5.
Comp Biochem Physiol C Toxicol Pharmacol ; 206-207: 17-22, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29471151

RESUMO

The herbicide atrazine (ATZ) is used worldwide in the control of annual grasses and broad-leaved weeds. The present study evaluated sperm quality parameters in zebrafish Danio rerio after 11-day exposure to nominal ATZ concentrations of 2, 10, and 100 µg L-1. All ATZ concentrations caused a decrease in motility, mitochondrial functionality, and membrane integrity, as measured using conventional microscopy or fluorescence microscopy with specific probes. The DNA integrity of sperm was not affected. The levels of expression of genes related to spermatogenesis, antioxidant defenses, and DNA repair were also investigated using RT-qPCR. The ATZ caused transcriptional repression of the spermatogenesis-related genes SRD5A2 and CFTR, the antioxidant defense genes SOD2 and GPX4B, and the DNA repair gene XPC. This is the first study to show that environmentally relevant concentrations of ATZ significantly affect the sperm quality in fish, possibly resulting in reduced fertility rates. In addition, we showed that the repression of genes related to spermatogenesis and cellular defense could be part of the mechanisms involved in the ATZ toxicity in the testes of male fish.


Assuntos
Atrazina/toxicidade , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Herbicidas/toxicidade , Espermatogênese/efeitos dos fármacos , Testículo/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Peixe-Zebra/fisiologia , 3-Oxo-5-alfa-Esteroide 4-Desidrogenase/química , 3-Oxo-5-alfa-Esteroide 4-Desidrogenase/genética , 3-Oxo-5-alfa-Esteroide 4-Desidrogenase/metabolismo , Animais , Proteínas de Ciclo Celular , Regulador de Condutância Transmembrana em Fibrose Cística/antagonistas & inibidores , Regulador de Condutância Transmembrana em Fibrose Cística/genética , Regulador de Condutância Transmembrana em Fibrose Cística/metabolismo , Glutationa Peroxidase/antagonistas & inibidores , Glutationa Peroxidase/genética , Glutationa Peroxidase/metabolismo , Masculino , Proteínas de Membrana/antagonistas & inibidores , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/enzimologia , Mitocôndrias/metabolismo , Membranas Mitocondriais/efeitos dos fármacos , Membranas Mitocondriais/enzimologia , Membranas Mitocondriais/metabolismo , Concentração Osmolar , Distribuição Aleatória , Proteínas de Saccharomyces cerevisiae , Motilidade Espermática/efeitos dos fármacos , Superóxido Dismutase/antagonistas & inibidores , Superóxido Dismutase/genética , Superóxido Dismutase/metabolismo , Testículo/citologia , Testículo/metabolismo , Xeroderma Pigmentoso/genética , Xeroderma Pigmentoso/metabolismo , Proteínas de Peixe-Zebra/antagonistas & inibidores , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo
6.
Biochimie ; 144: 122-133, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29097284

RESUMO

Dihydroxy-1-selenolane (DHS) previously reported to exhibit radioprotective activity was investigated to understand its mechanism of action in CHO cells of epithelial origin. DHS pre-treatment at 25 µM for 16 h significantly protected CHO cells from radiation (4-11 Gy)-induced delayed mitotic cell death. Further to examine, how increased cellular uptake can influence this mechanism, studies have been performed with DHS-C6, a lipophilic conjugate of DHS. Accordingly CHO cells pre-treated with DHS-C6, showed increased survival against radiation exposure. Notably treatment with both DHS and DHS-C6 significantly increased glutathione peroxidase (GPx) activity in cells by âˆ¼ 2.5 fold. Additionally, the compound DHS or DHS-C6 led to faster repair of DNA in irradiated cells and subsequently inhibited the G2/M arrest. Anticipating the role of GPx in radioprotection, our investigations revealed that addition of mercaptosuccinic acid, a pharmacological inhibitor of GPx reversed all the above effects of DHS or DHS-C6. Further inhibitors of check point kinase 1 (CHK1) and DNA-protein kinase (DNA-PK) although abrogated the radioprotective effect of DHS or DHS-C6 separately, did not show additive effect in combination with GPx inhibitor, suggesting their cross talk. In contrast to these results, both DHS and DHS-C6 treatment did not protect spleen lymphocytes from the radiation-induced apoptosis. Thus results confirmed that both DHS and DHS-C6 protected cells from radiation-induced mitotic death by augmenting DNA repair in a GPx dependant manner.


Assuntos
Ácidos Graxos/metabolismo , Glutationa Peroxidase/metabolismo , Compostos Heterocíclicos com 1 Anel/metabolismo , Compostos Heterocíclicos com 1 Anel/farmacologia , Compostos Organosselênicos/metabolismo , Compostos Organosselênicos/farmacologia , Protetores contra Radiação/metabolismo , Protetores contra Radiação/farmacologia , Animais , Células CHO , Morte Celular/efeitos dos fármacos , Morte Celular/efeitos da radiação , Cricetinae , Cricetulus , Dano ao DNA , Reparo do DNA/efeitos dos fármacos , Reparo do DNA/efeitos da radiação , Pontos de Checagem da Fase G2 do Ciclo Celular/efeitos dos fármacos , Pontos de Checagem da Fase G2 do Ciclo Celular/efeitos da radiação , Glutationa Peroxidase/antagonistas & inibidores , Pontos de Checagem da Fase M do Ciclo Celular/efeitos dos fármacos , Pontos de Checagem da Fase M do Ciclo Celular/efeitos da radiação , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/efeitos da radiação
7.
J Inorg Biochem ; 178: 94-105, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29125948

RESUMO

Here we present the preparation of 14 pairs of cis- and trans-diammine monochlorido platinum(II) complexes, coordinated to heterocycles (i.e., imidazole, 2-methylimidazole and pyrazole) and linked to various acylhydrazones, which were designed as potential inhibitors of the selenium-dependent enzymes glutathione peroxidase 1 (GPx-1) and thioredoxin reductase 1 (TrxR-1). However, no inhibition of bovine GPx-1 and only weak inhibition of murine TrxR-1 was observed in in vitro assays. Nonetheless, the cis configured diammine monochlorido Pt(II) complexes exhibited cytotoxic and apoptotic properties on various human cancer cell lines, whereas the trans configured complexes generally showed weaker potency with a few exceptions. On the other hand, the trans complexes were generally more likely to lack cross-resistance to cisplatin than the cis analogues. Platinum was found bound to the nuclear DNA of cancer cells treated with representative Pt complexes, suggesting that DNA might be a possible target. Thus, detailed in vitro binding experiments with DNA were conducted. Interactions of the compounds with calf thymus DNA were investigated, including Pt binding kinetics, circular dichroism (CD) spectral changes, changes in DNA melting temperatures, unwinding of supercoiled plasmids and ethidium bromide displacement in DNA. The CD results indicate that the most active cis configured pyrazole-derived complex causes unique structural changes in the DNA compared to the other complexes as well as to those caused by cisplatin, suggesting a denaturation of the DNA structure. This may be important for the antiproliferative activity of this compound in the cancer cells.


Assuntos
Ácido Aspártico/análogos & derivados , Condroitina/análogos & derivados , DNA/efeitos dos fármacos , Glutationa Peroxidase/antagonistas & inibidores , Compostos Organoplatínicos/síntese química , Platina/farmacologia , Selênio/farmacologia , Animais , Ácido Aspártico/química , Ácido Aspártico/farmacologia , Bovinos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Condroitina/química , Condroitina/farmacologia , DNA/química , Ativação Enzimática/efeitos dos fármacos , Enzimas/metabolismo , Concentração Inibidora 50 , Camundongos , Estrutura Molecular , Compostos Organoplatínicos/química , Compostos Organoplatínicos/farmacologia , Oxirredução , Platina/química , Platina/toxicidade , Selênio/química , Selênio/toxicidade
8.
Nature ; 551(7679): 247-250, 2017 11 09.
Artigo em Inglês | MEDLINE | ID: mdl-29088702

RESUMO

Acquired drug resistance prevents cancer therapies from achieving stable and complete responses. Emerging evidence implicates a key role for non-mutational drug resistance mechanisms underlying the survival of residual cancer 'persister' cells. The persister cell pool constitutes a reservoir from which drug-resistant tumours may emerge. Targeting persister cells therefore presents a therapeutic opportunity to impede tumour relapse. We previously found that cancer cells in a high mesenchymal therapy-resistant cell state are dependent on the lipid hydroperoxidase GPX4 for survival. Here we show that a similar therapy-resistant cell state underlies the behaviour of persister cells derived from a wide range of cancers and drug treatments. Consequently, we demonstrate that persister cells acquire a dependency on GPX4. Loss of GPX4 function results in selective persister cell ferroptotic death in vitro and prevents tumour relapse in mice. These findings suggest that targeting of GPX4 may represent a therapeutic strategy to prevent acquired drug resistance.


Assuntos
Apoptose/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Glutationa Peroxidase/antagonistas & inibidores , Neoplasias/tratamento farmacológico , Neoplasias/patologia , Animais , Antioxidantes/metabolismo , Avaliação Pré-Clínica de Medicamentos , Feminino , Humanos , Ferro/metabolismo , Masculino , Mesoderma/efeitos dos fármacos , Mesoderma/enzimologia , Mesoderma/patologia , Camundongos , Terapia de Alvo Molecular , Neoplasias/enzimologia , Recidiva , Ensaios Antitumorais Modelo de Xenoenxerto
9.
J Cell Biol ; 216(12): 4287-4297, 2017 12 04.
Artigo em Inglês | MEDLINE | ID: mdl-28972104

RESUMO

Increases in lipid peroxidation can cause ferroptosis, a form of cell death triggered by inhibition of glutathione peroxidase 4 (GPX4), which catalyzes the reduction of lipid peroxides and is a target of ferroptosis inducers, such as erastin. The α6ß4 integrin protects adherent epithelial and carcinoma cells from ferroptosis induced by erastin. In addition, extracellular matrix (ECM) detachment is a physiologic trigger of ferroptosis, which is evaded by α6ß4. The mechanism that enables α6ß4 to evade ferroptosis involves its ability to protect changes in membrane lipids that are proferroptotic. Specifically, α6ß4-mediated activation of Src and STAT3 suppresses expression of ACSL4, an enzyme that enriches membranes with long polyunsaturated fatty acids and is required for ferroptosis. Adherent cells lacking α6ß4 require an inducer, such as erastin, to undergo ferroptosis because they sustain GPX4 expression, despite their increase in ACSL4. In contrast, ECM detachment of cells lacking α6ß4 is sufficient to trigger ferroptosis because GPX4 is suppressed. This causal link between α6ß4 and ferroptosis has implications for cancer biology and therapy.


Assuntos
Coenzima A Ligases/genética , Células Epiteliais/metabolismo , Regulação Neoplásica da Expressão Gênica , Glutationa Peroxidase/genética , Integrina alfa6beta4/genética , Quinases da Família src/genética , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Apoptose/genética , Adesão Celular/efeitos dos fármacos , Linhagem Celular , Linhagem Celular Tumoral , Coenzima A Ligases/metabolismo , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/patologia , Matriz Extracelular/efeitos dos fármacos , Matriz Extracelular/metabolismo , Matriz Extracelular/ultraestrutura , Feminino , Glutationa Peroxidase/antagonistas & inibidores , Glutationa Peroxidase/metabolismo , Humanos , Integrina alfa6beta4/metabolismo , Ferro/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Piperazinas/farmacologia , Fator de Transcrição STAT3/genética , Fator de Transcrição STAT3/metabolismo , Transdução de Sinais , Quinases da Família src/metabolismo
10.
PLoS One ; 12(10): e0185943, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29016640

RESUMO

Virally mediated RNA interference (RNAi) to knock down injury-induced genes could improve functional outcome after traumatic brain injury (TBI); however, little is known about the consequences of gene knockdown on downstream cell signaling pathways and how RNAi influences neurodegeneration and behavior. Here, we assessed the effects of adeno-associated virus (AAV) siRNA vectors that target two genes with opposing roles in TBI pathogenesis: the allegedly detrimental neuronal nitric oxide synthase (nNOS) and the potentially protective glutathione peroxidase 1 (GPx-1). In rat hippocampal progenitor cells, three siRNAs that target different regions of each gene (nNOS, GPx-1) effectively knocked down gene expression. However, in vivo, in our rat model of fluid percussion brain injury, the consequences of AAV-siRNA were variable. One nNOS siRNA vector significantly reduced the number of degenerating hippocampal neurons and showed a tendency to improve working memory. GPx-1 siRNA treatment did not alter TBI-induced neurodegeneration or working memory deficits. Nevertheless, microarray analysis of laser captured, virus-infected neurons showed that knockdown of nNOS or GPx-1 was specific and had broad effects on downstream genes. Since nNOS knockdown only modestly ameliorated TBI-induced working memory deficits, despite widespread genomic changes, manipulating expression levels of single genes may not be sufficient to alter functional outcome after TBI.


Assuntos
Lesões Encefálicas Traumáticas/genética , Dependovirus/genética , Glutationa Peroxidase/genética , Transtornos da Memória/genética , Óxido Nítrico Sintase Tipo I/genética , Interferência de RNA , Animais , Lesões Encefálicas Traumáticas/metabolismo , Lesões Encefálicas Traumáticas/fisiopatologia , Dependovirus/metabolismo , Perfilação da Expressão Gênica , Técnicas de Silenciamento de Genes , Glutationa Peroxidase/antagonistas & inibidores , Glutationa Peroxidase/metabolismo , Hipocampo/metabolismo , Hipocampo/fisiopatologia , Microdissecção e Captura a Laser , Masculino , Aprendizagem em Labirinto , Transtornos da Memória/metabolismo , Transtornos da Memória/fisiopatologia , Memória de Curto Prazo/fisiologia , Redes e Vias Metabólicas/genética , Análise em Microsséries , Células-Tronco Neurais/citologia , Células-Tronco Neurais/metabolismo , Neurônios/metabolismo , Neurônios/patologia , Óxido Nítrico Sintase Tipo I/antagonistas & inibidores , Óxido Nítrico Sintase Tipo I/metabolismo , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Ratos , Ratos Sprague-Dawley , Transdução de Sinais
11.
Free Radic Biol Med ; 112: 597-607, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-28893626

RESUMO

Low-density lipoprotein nanoparticles reconstituted with the natural omega-3 fatty acid, docosahexaenoic acid (LDL-DHA), have been reported to selectively kill hepatoma cells and reduce the growth of orthotopic liver tumors in the rat. To date, little is known about the cell death pathways by which LDL-DHA nanoparticles kill tumor cells. Here we show that the LDL-DHA nanoparticles are cytotoxic to both rat hepatoma and human hepatocellular carcinoma (HCC) cell lines. Following LDL-DHA treatment both rat and human HCC cells experience pronounced lipid peroxidation, depletion of glutathione and inactivation of the lipid antioxidant glutathione peroxidase-4 (GPX4) prior to cell death. Inhibitor studies revealed that the treated HCC cells die independent of apoptotic, necroptotic or autophagic pathways, but require the presence of cellular iron. These hallmark features are consistent and were later confirmed to reflect ferroptosis, a novel form of nonapoptotic iron-dependent cell death. In keeping with the mechanisms of ferroptosis cell death, GPX4 was also found to be a central regulator of LDL-DHA induced tumor cell killing. We also investigated the effects of LDL-DHA treatments in mice bearing human HCC tumor xenografts. Intratumoral injections of LDL-DHA severely inhibited the growth of HCC xenografts long term. Consistent with our in vitro findings, the LDL-DHA treated HCC tumors experienced ferroptotic cell death characterized by increased levels of tissue lipid hydroperoxides and suppression of GPX4 expression. CONCLUSION: LDL-DHA induces cell death in HCC cells through the ferroptosis pathway, this represents a novel molecular mechanism of anticancer activity for LDL-DHA nanoparticles.


Assuntos
Antineoplásicos/farmacologia , Carcinoma Hepatocelular/tratamento farmacológico , Ácidos Docosa-Hexaenoicos/farmacologia , Ferro/metabolismo , Lipoproteínas LDL/farmacologia , Neoplasias Hepáticas/tratamento farmacológico , Nanopartículas/administração & dosagem , Animais , Antineoplásicos/química , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patologia , Morte Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Ácidos Docosa-Hexaenoicos/química , Expressão Gênica , Glutationa/antagonistas & inibidores , Glutationa/metabolismo , Glutationa Peroxidase/antagonistas & inibidores , Glutationa Peroxidase/genética , Glutationa Peroxidase/metabolismo , Células Hep G2 , Humanos , Injeções Intralesionais , Peroxidação de Lipídeos/efeitos dos fármacos , Peróxidos Lipídicos/agonistas , Peróxidos Lipídicos/metabolismo , Lipoproteínas LDL/química , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos SCID , Nanopartículas/química , Ratos , Ensaios Antitumorais Modelo de Xenoenxerto
12.
Biochem Pharmacol ; 146: 42-52, 2017 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-28947276

RESUMO

Auranofin is a thiol-reactive gold (I)-containing compound with potential asa chemotherapeutic. Auranofin has the capacity to selectively inhibit endogenous antioxidant enzymes thioredoxin reductase (TrxR) and glutathione peroxidase (GPx), resulting in oxidative stress and the initiation of a pro-apoptotic cascade. The effect of Auranofin exposure on TrxR and GPx, and the potential for cellular protection through selenium supplementation was examined in the non-cancerous human cell line Swan-71. Auranofin exposure resulted in a concentration dependent differential inhibition of selenoprotein antioxidants. Significant inhibition of TrxR was observed at 20nM Auranofin with inhibition of GPx from 10µM. Significant increases in reactive oxygen species (ROS) were associated with antioxidant inhibition at Auranofin concentrations of 100nM (TrxR inhibition) and 10µM (TrxR and GPx inhibition), respectively. Evaluation of mitochondrial respiration demonstrated significant reductions in routine and maximal respiration at both 100nM and 10µM Auranofin. Auranofin treatment at concentrations of 10µM and higher concentrations resulted in a ∼68% decrease in cellular viability and was associated with elevations in pro-apoptotic markers cytochrome c flux control factor (FCFc) at concentration of 100nM and mitochondrial Bax at 10µM. The supplementation of selenium (100nM) prior to treatment had a generalized protective affect through the restoration of antioxidant activity with a significant increase in TrxR and GPx activity, a significant reduction in ROS and associated improvement in mitochondrial respiration and cellular viability (10µM ∼48% increase). Selenium supplementation reduced the FCFc at low doses of Auranofin (<10µM) however no effect was noted on either FCFc or Bax at concentrations above 10µM. The inhibition of antioxidant systems in non-cancerous cells by Auranofin is strongly dose dependent, and this inhibition can be altered by selenium exposure. Therefore, Auranofin dose and the selenium status of patients are important considerations in the therapeutic use of Auranofin as an agent of chemosensitization.


Assuntos
Antioxidantes/metabolismo , Auranofina/farmacologia , Mitocôndrias/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Selênio/farmacologia , Apoptose/efeitos dos fármacos , Apoptose/fisiologia , Biomarcadores , Linhagem Celular , Sobrevivência Celular , Regulação Enzimológica da Expressão Gênica , Glutationa Peroxidase/antagonistas & inibidores , Humanos , Mitocôndrias/metabolismo , Espécies Reativas de Oxigênio , Selênio/administração & dosagem , Tiorredoxina Dissulfeto Redutase/antagonistas & inibidores
13.
ACS Chem Biol ; 12(10): 2538-2545, 2017 10 20.
Artigo em Inglês | MEDLINE | ID: mdl-28837769

RESUMO

Two aromatic amines (ferrostatin-1 and liproxstatin-1) were recently identified from high-throughput screening efforts to uncover potent inhibitors of ferroptosis, the necrotic-like cell death induced by inhibition of glutathione peroxidase 4 (GPX4), deletion of the corresponding gpx4 gene, or starvation of GPX4 of its reducing cosubstrate, glutathione (GSH). We have since demonstrated that these two aromatic amines are highly effective radical-trapping antioxidants (RTAs) in lipid bilayers, suggesting that they subvert ferroptosis by inhibiting lipid peroxidation (autoxidation) and, thus, that this process drives the execution of ferroptosis. Herein, we show that diarylamine RTAs used to protect petroleum-derived products from autoxidation can be potent inhibitors of ferroptosis. The diarylamines investigated include representative examples of additives to engine oils, greases and rubber (4,4'-dialkyldiphenylamines), core structures of dyes and pharmaceuticals (phenoxazines and phenothiazines), and aza-analogues of these three classes of compounds that we have recently shown can be modified to achieve much greater reactivity. We find that regardless of how ferroptosis is induced (GPX4 inhibition, gpx4 deletion or GSH depletion), compounds which possess good RTA activity in organic solution (kinh > 105 M-1 s-1) and lipid bilayers (kinh > 104 M-1 s-1) are generally potent inhibitors of ferroptosis (in mouse embryonic fibroblasts). Likewise, structural analogs that do not possess RTA activity are devoid of antiferroptotic activity. These results further support the argument that lipid peroxidation (autoxidation) plays a major role in the mechanism of cell death induced by either GPX4 inhibition, gpx4 deletion, or GSH depletion. Moreover, it offers clear direction that ongoing medicinal chemistry efforts on liproxstatin and ferrostatin derivatives, which have been proposed as lead compounds for the treatment and/or prevention of ischemia/reperfusion injury, renal failure, and neurodegeneration, can be widened to include other aminic RTAs. To aid in these efforts, some relevant structure-reactivity relationships are discussed.


Assuntos
Aminas/química , Antioxidantes/química , Antioxidantes/farmacologia , Autofagia/efeitos dos fármacos , Glutationa Peroxidase/antagonistas & inibidores , Animais , Apoptose/efeitos dos fármacos , Autofagia/fisiologia , Linhagem Celular , Sobrevivência Celular , Dioxanos/toxicidade , Fibroblastos/efeitos dos fármacos , Deleção de Genes , Regulação Enzimológica da Expressão Gênica , Glutationa Peroxidase/genética , Glutationa Peroxidase/metabolismo , Humanos , Peroxidação de Lipídeos/fisiologia , Lipossomos , Camundongos , Oxirredução
14.
Biochem Pharmacol ; 140: 41-52, 2017 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-28595877

RESUMO

Ferroptosis has recently been identified as a mode of programmed cell death. However, little is yet known about the signaling mechanism. Here, we report that lipoxygenases (LOX) contribute to the regulation of RSL3-induced ferroptosis in acute lymphoblastic leukemia (ALL) cells. We show that the glutathione (GSH) peroxidase 4 (GPX4) inhibitor RSL3 triggers lipid peroxidation, production of reactive oxygen species (ROS) and cell death in ALL cells. All these events are impeded in the presence of Ferrostatin-1 (Fer-1), a small-molecule inhibitor of lipid peroxidation. Also, lipid peroxidation and ROS production precede the induction of cell death, underscoring their contribution to cell death upon exposure to RSL3. Importantly, LOX inhibitors, including the selective 12/15-LOX inhibitor Baicalein and the pan-LOX inhibitor nordihydroguaiaretic acid (NDGA), protect ALL cells from RSL3-stimulated lipid peroxidation, ROS generation and cell death, indicating that LOX contribute to ferroptosis. RSL3 triggers lipid peroxidation and cell death also in FAS-associated Death Domain (FADD)-deficient cells which are resistant to death receptor-induced apoptosis indicating that the induction of ferroptosis may bypass apoptosis resistance. By providing new insights into the molecular regulation of ferroptosis, our study contributes to the development of novel treatment strategies to reactivate programmed cell death in ALL.


Assuntos
Antineoplásicos/farmacologia , Carbolinas/farmacologia , Glutationa Peroxidase/antagonistas & inibidores , Peroxidação de Lipídeos/efeitos dos fármacos , Inibidores de Lipoxigenase/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamento farmacológico , Antineoplásicos/química , Antioxidantes/farmacologia , Araquidonato 12-Lipoxigenase/química , Araquidonato 12-Lipoxigenase/genética , Araquidonato 12-Lipoxigenase/metabolismo , Araquidonato 15-Lipoxigenase/química , Araquidonato 15-Lipoxigenase/genética , Araquidonato 15-Lipoxigenase/metabolismo , Carbolinas/antagonistas & inibidores , Morte Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Cicloexilaminas/farmacologia , Proteína de Domínio de Morte Associada a Fas/genética , Proteína de Domínio de Morte Associada a Fas/metabolismo , Flavanonas/farmacologia , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Glutationa Peroxidase/genética , Glutationa Peroxidase/metabolismo , Humanos , Cinética , Masoprocol/farmacologia , Proteínas de Neoplasias/antagonistas & inibidores , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Fenilenodiaminas/farmacologia , Leucemia-Linfoma Linfoblástico de Células Precursoras/enzimologia , Leucemia-Linfoma Linfoblástico de Células Precursoras/metabolismo , Espécies Reativas de Oxigênio/antagonistas & inibidores , Espécies Reativas de Oxigênio/metabolismo , alfa-Tocoferol/farmacologia
15.
Mol Med Rep ; 15(6): 4132-4138, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28487964

RESUMO

The present study aimed to describe the expression and purification of cyclophilin-type peptidylprolyl cis-trans isomerase (PPI) from the red alga Pyropia yezoensis. The antioxidant activity of the purified protein was also demonstrated, based on its ability to act against oxidative stress in HepG2 human hepatocellular carcinoma cells. HepG2 cells that were treated with recombinant PPI protein exhibited a reduction in the formation of hydrogen peroxide (H2O2)­mediated reactive oxygen species (ROS). In HepG2 cells, treatment of recombinant PPI protein expression diminished H2O2­mediated oxidative stress and restored both the expression and the activity of certain antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and thioredoxin reductase (TRR). CAT, SOD and TRR activities were upregulated by treatment with the purified protein. CAT mRNA expression was significantly increased in HepG2 cells treated with recombinant PPI protein. These enzymes are the first line of antioxidant defense against ROS generated in times of oxidative stress. Accordingly, data from the present study indicate that the recombinant PPI protein is able to regulate the expression of antioxidant enzymes. Recombinant PPI has antioxidant properties that prevent oxidative stress­induced toxicity, enhance cell viability, decrease ROS production and inhibit oxidative damage and mitochondrial dysfunction in HepG2 cells. Therefore, the present study hypothesizes that the recombinant PPI protein has the potential to protect the liver against oxidative stress­induced cell damage and should be considered as an antioxidant.


Assuntos
Antioxidantes/farmacologia , Ciclofilinas/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Extratos Vegetais/farmacologia , Rodófitas/química , Catalase/antagonistas & inibidores , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Glutationa Peroxidase/antagonistas & inibidores , Células Hep G2 , Humanos , Peróxido de Hidrogênio/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Proteínas Recombinantes/farmacologia , Superóxido Dismutase/antagonistas & inibidores
16.
J Appl Toxicol ; 37(9): 1073-1081, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28383113

RESUMO

Exposure to methylmercury (MeHg), an important environmental toxicant, may lead to serious health risks, damaging various organs and predominantly affecting the brain function. The toxicity of MeHg can be related to the inhibition of important selenoenzymes, such as glutathione peroxidase (GPx) and thioredoxin reductase (TrxR). Experimental studies have shown that selenocompounds play an important role as cellular detoxifiers and protective agents against the harmful effects of mercury. The present study investigated the mechanisms by which diphenyl diselenide [(PhSe)2 ] and ebselen interfered with the interaction of mercury (MeHg) and selenoenzymes (TrxR and GPx) in an in vitro experimental model of cultured human neuroblastoma cells (SH-SY5Y). Our results established that (PhSe)2 and ebselen increased the activity and expression of TrxR. In contrast, MeHg inhibited TrxR activity even at low doses (0.5 µm). Coexposure to selenocompounds and MeHg showed a protective effect of (PhSe)2 on both the activity and expression of TrxR. When selenoenzyme GPx was evaluated, selenocompounds did not alter its activity or expression significantly, whereas MeHg inhibited the activity of GPx (from 1 µm). Among the selenocompounds only (PhSe)2 significantly protected against the effects of MeHg on GPx activity. Taken together, these results indicate a potential use for ebselen and (PhSe)2 against MeHg toxicity. Furthermore, for the first time, we have demonstrated that (PhSe)2 caused a more pronounced upregulation of TrxR than ebselen in neuroblastoma cells, likely reflecting an important molecular mechanism involved in the antioxidant properties of this compound. Copyright © 2017 John Wiley & Sons, Ltd.


Assuntos
Antioxidantes/farmacologia , Azóis/farmacologia , Derivados de Benzeno/farmacologia , Glutationa Peroxidase/metabolismo , Compostos de Metilmercúrio/toxicidade , Compostos Organosselênicos/farmacologia , Tiorredoxina Dissulfeto Redutase/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Glutationa Peroxidase/antagonistas & inibidores , Glutationa Peroxidase/genética , Humanos , Neuroblastoma/induzido quimicamente , Neuroblastoma/tratamento farmacológico , Tiorredoxina Dissulfeto Redutase/antagonistas & inibidores , Tiorredoxina Dissulfeto Redutase/genética
17.
IUBMB Life ; 69(6): 423-434, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-28276141

RESUMO

Ferroptosis is a recently described form of regulated necrotic cell death, which appears to contribute to a number of diseases, such as tissue ischemia/reperfusion injury, acute renal failure, and neurodegeneration. A hallmark of ferroptosis is iron-dependent lipid peroxidation, which can be inhibited by the key ferroptosis regulator glutathione peroxidase 4(Gpx4), radical trapping antioxidants and ferroptosis-specific inhibitors, such as ferrostatins and liproxstatins, as well as iron chelation. Although great strides have been made towards a better understanding of the proximate signals of distinctive lipid peroxides in ferroptosis, still little is known about the mechanistic implication of iron in the ferroptotic process. Hence, this review aims at summarizing recent advances in our understanding to what is known about enzymatic and nonenzymatic routes of lipid peroxidation, the involvement of iron in this process and the identification of novel players in ferroptotic cell death. Additionally, we review early works carried out long time before the term "ferroptosis" was actually introduced but which were instrumental in a better understanding of the role of ferroptosis in physiological and pathophysiological contexts. © 2017 IUBMB Life, 69(6):423-434, 2017.


Assuntos
Antioxidantes/farmacologia , Glutationa Peroxidase/antagonistas & inibidores , Distúrbios do Metabolismo do Ferro/metabolismo , Ferro/metabolismo , Distrofias Neuroaxonais/metabolismo , Insuficiência Renal/metabolismo , Traumatismo por Reperfusão/metabolismo , Animais , Morte Celular/efeitos dos fármacos , Morte Celular/genética , Cicloexilaminas/farmacologia , Glutationa Peroxidase/genética , Glutationa Peroxidase/metabolismo , Humanos , Quelantes de Ferro/uso terapêutico , Distúrbios do Metabolismo do Ferro/tratamento farmacológico , Distúrbios do Metabolismo do Ferro/genética , Distúrbios do Metabolismo do Ferro/patologia , Peroxidação de Lipídeos/efeitos dos fármacos , Necrose/genética , Necrose/metabolismo , Necrose/patologia , Distrofias Neuroaxonais/tratamento farmacológico , Distrofias Neuroaxonais/genética , Distrofias Neuroaxonais/patologia , Fenilenodiaminas/farmacologia , Quinoxalinas/farmacologia , Insuficiência Renal/tratamento farmacológico , Insuficiência Renal/genética , Insuficiência Renal/patologia , Traumatismo por Reperfusão/genética , Traumatismo por Reperfusão/patologia , Traumatismo por Reperfusão/prevenção & controle , Compostos de Espiro/farmacologia
18.
Neurochem Int ; 107: 23-32, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28043837

RESUMO

During ischemic stroke, neurons and glia are subjected to damage during the acute and neuroinflammatory phases of injury. Production of reactive oxygen species (ROS) from calcium dysregulation in neural cells and the invasion of activated immune cells are responsible for stroke-induced neurodegeneration. Scientists have failed thus far to identify antioxidant-based drugs that can enhance neural cell survival and improve recovery after stroke. However, several groups have demonstrated success in protecting against stroke by increasing expression of antioxidant enzymes in neural cells. These enzymes, which include but are not limited to enzymes in the glutathione peroxidase, catalase, and superoxide dismutase families, degrade ROS that otherwise damage cellular components such as DNA, proteins, and lipids. Several groups have identified cellular therapies including neural stem cells and human umbilical cord blood cells, which exert neuroprotective and oligoprotective effects through the release of pro-survival factors that activate PI3K/Akt signaling to upregulation of antioxidant enzymes. Other studies demonstrate that treatment with soluble factors released by these cells yield similar changes in enzyme expression after stroke. Treatment with the cytokine leukemia inhibitory factor increases the expression of peroxiredoxin IV and metallothionein III in glia and boosts expression of superoxide dismutase 3 in neurons. Through cell-specific upregulation of these enzymes, LIF and other Akt-inducing factors have the potential to protect multiple cell types against damage from ROS during the early and late phases of ischemic damage.


Assuntos
Antioxidantes/administração & dosagem , Isquemia Encefálica/tratamento farmacológico , Isquemia Encefálica/enzimologia , Acidente Vascular Cerebral/tratamento farmacológico , Acidente Vascular Cerebral/enzimologia , Animais , Catalase/antagonistas & inibidores , Catalase/biossíntese , Sistemas de Liberação de Medicamentos/tendências , Glutationa Peroxidase/antagonistas & inibidores , Glutationa Peroxidase/biossíntese , Humanos , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/fisiologia , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Superóxido Dismutase/antagonistas & inibidores , Superóxido Dismutase/biossíntese
19.
Cancer Res ; 77(8): 2064-2077, 2017 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-28130223

RESUMO

Ferroptosis is a form of regulated cell death driven by oxidative injury promoting lipid peroxidation, although detailed molecular regulators are largely unknown. Here, we show that heatshock 70-kDa protein 5 (HSPA5) negatively regulates ferroptosis in human pancreatic ductal adenocarcinoma (PDAC) cells. Mechanistically, activating transcription factor 4 (ATF4) resulted in the induction of HSPA5, which in turn bound glutathione peroxidase 4 (GPX4) and protected against GPX4 protein degradation and subsequent lipid peroxidation. Importantly, the HSPA5-GPX4 pathway mediated ferroptosis resistance, limiting the anticancer activity of gemcitabine. Genetic or pharmacologic inhibition of the HSPA5-GPX4 pathway enhanced gemcitabine sensitivity by disinhibiting ferroptosis in vitro and in both subcutaneous and orthotopic animal models of PDAC. Collectively, these findings identify a novel role of HSPA5 in ferroptosis and suggest a potential therapeutic strategy for overcoming gemcitabine resistance. Cancer Res; 77(8); 2064-77. ©2017 AACR.


Assuntos
Carcinoma Ductal Pancreático/metabolismo , Carcinoma Ductal Pancreático/patologia , Proteínas de Choque Térmico/metabolismo , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/patologia , Fator 4 Ativador da Transcrição/metabolismo , Animais , Antimetabólitos Antineoplásicos/farmacologia , Morte Celular/fisiologia , Linhagem Celular Tumoral , Desoxicitidina/análogos & derivados , Desoxicitidina/farmacologia , Glutationa Peroxidase/antagonistas & inibidores , Glutationa Peroxidase/genética , Glutationa Peroxidase/metabolismo , Proteínas de Choque Térmico/antagonistas & inibidores , Proteínas de Choque Térmico/biossíntese , Proteínas de Choque Térmico/genética , Humanos , Peroxidação de Lipídeos , Camundongos
20.
Biochem Biophys Res Commun ; 482(2): 195-201, 2017 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-27836545

RESUMO

The phospholipid hydroperoxidase glutathione peroxidase (GPX4) is an enzyme that reduces lipid hydroperoxides in lipid membranes. Recently, GPX4 has been investigated as a target molecule that induces iron-dependent cell death (ferroptosis) selectively in cancer cells that express mutant Ras. GPX4 inhibitors have the potential to become novel anti-cancer drugs. However, there are no druggable pockets for conventional small molecules on the molecular surface of GPX4. To generate GPX4 inhibitors, we examined the use of peptides as an alternative to small molecules. By screening peptide libraries displayed on T7 phages, and analyzing the X-ray crystal structures of the peptides, we successfully identified one peptide that binds to near Sec73 of catalytic site and two peptides that bind to another site on GPX4. To our knowledge, this is the first study reporting GPX4 inhibitory peptides and their structural information.


Assuntos
Avaliação Pré-Clínica de Medicamentos/métodos , Inibidores Enzimáticos/química , Glutationa Peroxidase/antagonistas & inibidores , Biblioteca de Peptídeos , Peptídeos/química , Bacteriófago T7/genética , Sítios de Ligação , Ativação Enzimática , Ligação Proteica , Conformação Proteica
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