RESUMO
Monothioarsenate (MTA) is a newly discovered arsenic (As) compound that can be formed under reduced sulfur conditions, mainly in paddy soil pore waters. It is structurally similar to arsenate As(V) and inorganic phosphate (Pi), which is taken up through phosphate transporters. Due to the similarity between As(V) and Pi, As(V) enters into plants instead of Pi. The important role played by phytochelatin (PC), glutathione (GSH), and the PC-vacuolar transporters ABCC1 and ABCC2 under As stress in plants is well known. However, the plant uptake and mechanisms surrounding MTA still have not been completely addressed. This investigation was divided in two stages: first, several hydroponic assays were set up to establish the sensibility-tolerance of wild-type Arabidopsis thaliana (accession Columbia-0, Col-0). Then Col-0 was used as a control plant to evaluate the effects of As(V) or MTA in (PC)-deficient mutant (cad1-3), glutathione biosynthesis mutant (cad2), and PC transport (abcc1-2). The inhibitory concentration (IC50) root length was calculated for both As species. According to the results, both arsenic species (As(V) and MTA) exhibited high toxicity for the genotypes evaluated. This could mean that these mechanisms play a constitutive role in MTA detoxification. Second, for the Pi-MTA and As(V)-Pi competition assays, a series of experiments on hydroponic seedlings of A. thaliana were carried out using Col-0 and a pht1;1. The plants were grown under increasing Pi concentrations (10 µM, 0.1 mM, or 1 mM) at 10 µM As(V) or 50 µM MTA. The total As concentration in the roots was significantly lower in plants exposed to MTA, there being less As content in the pht1;1 mutant at the lowest Pi concentrations tested compared with the As(V)/Pi treatments. In addition, a higher rate of As translocation from the roots to the shoots under MTA was observed in comparison to the As(V)-treatments.
Assuntos
Arabidopsis , Arsênio , Arsenicais , Arsênio/farmacologia , Fosfatos/farmacologia , Hidroponia , Transporte Biológico , Arsenicais/farmacologia , Plantas , Arabidopsis/genética , Raízes de Plantas , GlutationaRESUMO
BACKGROUND: Arsenic trioxide (As2O3), a drug that has been used in China for approximately two thousand years, induces cell death in a variety of cancer cell types, including neuroblastoma (NB). The tyrosine kinase receptor (Trk) family comprises three members, namely TrkA, TrkB and TrkC. Various studies have confirmed that TrkA and TrkC expression is associated with a good prognosis in NB, while TrkB overexpression can lead to tumor cell growth and invasive metastasis. Previous studies have shown that As2O3 can inhibit the growth and proliferation of a human NB cell line and can also affect the N-Myc mRNA expression. It remains unclear whether As2O3 regulates Trks for the purposes of treating NB. METHODS: The aim of the present study was to investigate the effect of As2O3 on Trk expression in NB cell lines and its potential therapeutic efficacy. SK-N-SH cells were grown with increasing doses of As2O3 at different time points. We cultured SK-N-SH cells, which were treated with increasing doses of As2O3 at different time points. Trk expression in the NB samples was quantified by immunohistochemistry, and the cell cycle was analyzed by flow cytometry. TrkA, TrkB and TrkC mRNA expression was evaluated by real-time PCR analysis. RESULTS: Immunohistochemical and real-time PCR analyses indicated that TrkA and TrkC were over-expressed in NB, and specifically during stages 1, 2 and 4S of the disease progression. TrkB expression was increased in stage 3 and 4 NB. As2O3 significantly arrested SK-N-SH cells in the G2/M phase. In addition, TrkA, TrkB and TrkC expression levels were significantly upregulated by higher concentrations of As2O3 treatment, notably in the 48-h treatment period. Our findings suggested that to achieve the maximum effect and appropriate regulation of Trk expression in NB stages 1, 2 and 4S, As2O3 treatment should be at relatively higher concentrations for longer delivery times;however, for NB stages 3 and 4, an appropriate concentration and infusion time for As2O3 must be carefully determined. CONCLUSION: The present findings suggested that As2O3 induced Trk expression in SK-N-SH cells to varying degrees and may be a promising adjuvant to current treatments for NB due to its apoptotic effects.
Assuntos
Arsenicais/farmacologia , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Glicoproteínas de Membrana/efeitos dos fármacos , Neuroblastoma/metabolismo , Óxidos/farmacologia , Receptor trkB/efeitos dos fármacos , Trióxido de Arsênio , Linhagem Celular Tumoral/efeitos dos fármacos , Linhagem Celular Tumoral/metabolismo , Humanos , Glicoproteínas de Membrana/metabolismo , Neuroblastoma/patologia , Receptor trkB/metabolismoRESUMO
Interactions of arsenic with essential trace elements may result in disturbances on body homeostasis. In the present study, we aimed to investigate the effects of different arsenic compounds on micromineral content and antioxidant enzyme activities in rat liver. Male Wistar rats were randomly divided into five groups and exposed to sodium arsenite and sodium arsenate at 0.01 and 10 mg/L for 8 weeks in drinking water. The concentration of arsenic increased in the liver of all arsenic-exposed animals. The proportion of zinc and copper increased in animals exposed to 0.01 mg/L sodium arsenite. In addition, these animals presented a reduction in magnesium and sodium content. Superoxide dismutase activity decreased mainly in arsenite-exposed animals, whereas catalase activity decreased in animals exposed to 10 mg/L sodium arsenate. Further, exposure to sodium arsenate at 10 mg/L altered copper and magnesium content in the liver, and reduced total protein levels. Overall, both arsenic compounds altered the liver histology, with reduction in the proportion of cytoplasm and hepatocyte, and increased the percentage of sinusoidal capillaries and macrophages. In conclusion, our findings showed that oral exposure to arsenic compounds disturbs the trace elements balance in the liver, especially at low concentration, altering enzymatic and stereological parameters. We concluded that despite the increase in trace elements content, the antioxidant enzyme activities were downregulated and did not prevent morphological alterations in the liver of animals exposed to both arsenic compounds.
Assuntos
Antioxidantes/metabolismo , Arsenicais/farmacologia , Fígado/efeitos dos fármacos , Fígado/metabolismo , Animais , Arseniatos/farmacologia , Arsenitos/farmacologia , Fígado/enzimologia , Masculino , Minerais/metabolismo , Ratos , Ratos WistarRESUMO
BACKGROUND: Arsenic trioxide (As2O3), a drug that has been used in China for approximately two thousand years, induces cell death in a variety of cancer cell types, including neuroblastoma (NB). The tyrosine kinase receptor (Trk) family comprises three members, namely TrkA, TrkB and TrkC. Various studies have confirmed that TrkA and TrkC expression is associated with a good prognosis in NB, while TrkB overexpression can lead to tumor cell growth and invasive metastasis. Previous studies have shown that As2O3 can inhibit the growth and proliferation of a human NB cell line and can also affect the N-Myc mRNA expression. It remains unclear whether As2O3 regulates Trks for the purposes of treating NB. METHODS: The aim of the present study was to investigate the effect of As2O3 on Trk expression in NB cell lines and its potential therapeutic efficacy. SK-N-SH cells were grown with increasing doses of As2O3 at different time points. We cultured SK-N-SH cells, which were treated with increasing doses of As2O3 at different time points. Trk expression in the NB samples was quantified by immunohistochemistry, and the cell cycle was analyzed by flow cytometry. TrkA, TrkB and TrkC mRNA expression was evaluated by real-time PCR analysis. RESULTS: Immunohistochemical and real-time PCR analyses indicated that TrkA and TrkC were over-expressed in NB, and specifically during stages 1, 2 and 4S of the disease progression. TrkB expression was increased in stage 3 and 4 NB. As2O3significantly arrested SK-N-SH cells in the G2/M phase. In addition, TrkA, TrkB and TrkC expression levels were significantly upregulated by higher concentrations of As2O3 treatment, notably in the 48-h treatment period. Our findings suggested that to achieve the maximum effect and appropriate regulation of Trk expression in NB stages 1, 2 and 4S, As2O3 treatment should be at relatively higher concentrations for longer delivery times;however, for NB stages 3 and 4, an appropriate concentration and infusion time for As2O3 must be carefully determined. CONCLUSION: The present findings suggested that As2O3 induced Trk expression in SK-N-SH cells to varying degrees and may be a promising adjuvant to current treatments for NB due to its apoptotic effects.
Assuntos
Humanos , Óxidos/farmacologia , Arsenicais/farmacologia , Glicoproteínas de Membrana/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Receptor trkB/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Neuroblastoma/metabolismo , Glicoproteínas de Membrana/metabolismo , Receptor trkB/metabolismo , Linhagem Celular Tumoral/efeitos dos fármacos , Linhagem Celular Tumoral/metabolismo , Trióxido de Arsênio , Neuroblastoma/patologiaRESUMO
Ki-1/57 is a nuclear and cytoplasmic regulatory protein first identified in malignant cells from Hodgkin's lymphoma. It is involved in gene expression regulation on both transcriptional and mRNA metabolism levels. Ki-1/57 belongs to the family of intrinsically unstructured proteins and undergoes phosphorylation by PKC and methylation by PRMT1. Previous characterization of its protein interaction profile by yeast two-hybrid screening showed that Ki-1/57 interacts with proteins of the SUMOylation machinery, the SUMO E2 conjugating enzyme UBC9 and the SUMO E3 ligase PIAS3, which suggested that Ki-1/57 could be involved with this process. Here we identified seven potential SUMO target sites (lysine residues) on Ki-1/57 sequence and observed that Ki-1/57 is modified by SUMO proteins in vitro and in vivo. We showed that SUMOylation of Ki-1/57 occurred on lysines 213, 276, and 336. In transfected cells expressing FLAG-Ki-1/57 wild-type, its paralog FLAG-CGI-55 wild-type, or their non-SUMOylated triple mutants, the number of PML-nuclear bodies (PML-NBs) is reduced compared with the control cells not expressing the constructs. More interestingly, after treating cells with arsenic trioxide (As2O3), the number of PML-NBs is no longer reduced when the non-SUMOylated triple mutant Ki-1/57 is expressed, suggesting that the SUMOylation of Ki-1/57 has a role in the control of As2O3-induced PML-NB formation. A proteome-wide analysis of Ki-1/57 partners in the presence of either SUMO-1 or SUMO-2 suggests that the involvement of Ki-1/57 with the regulation of gene expression is independent of the presence of either SUMO-1 or SUMO-2; however, the presence of SUMO-1 strongly influences the interaction of Ki-1/57 with proteins associated with cellular metabolism, maintenance, and cell cycle.
Assuntos
Fatores de Regulação Miogênica/metabolismo , Mapeamento de Interação de Proteínas , Processamento de Proteína Pós-Traducional , Proteínas de Ligação a RNA/metabolismo , Proteína SUMO-1/metabolismo , Proteínas Modificadoras Pequenas Relacionadas à Ubiquitina/metabolismo , Trióxido de Arsênio , Arsenicais/farmacologia , Ciclo Celular/genética , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/genética , Núcleo Celular/metabolismo , Clonagem Molecular , Escherichia coli/genética , Escherichia coli/metabolismo , Células HEK293 , Células HeLa , Humanos , Lisina , Fatores de Regulação Miogênica/genética , Oligopeptídeos/genética , Oligopeptídeos/metabolismo , Óxidos/farmacologia , Plasmídeos/química , Plasmídeos/metabolismo , Ligação Proteica , Biossíntese de Proteínas , Proteínas de Ligação a RNA/genética , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Proteína SUMO-1/genética , Proteínas Modificadoras Pequenas Relacionadas à Ubiquitina/genética , Sumoilação , Transcrição GênicaRESUMO
The transport of proteins across the intestinal epithelium of insects is still not well understood. There is evidence that vicilin, a major storage protein of cowpea seeds (Vigna unguiculata), is internalized in larvae of the seed-beetle Callosobruchus maculatus. It has been reported that this vicilin interacts with proteins present in the microvillar membranes of columnar cells along the digestive tract of the larvae. In the present work, we studied the cellular pathway involved in endocytosis of vicilin in larval C. maculatus by employing ex vivo experiments. In the ex vivo approach, we incubated FITC-labelled vicilin with isolated midgut wholemounts in the absence or in the presence of endocytosis inhibitors. The fate of labelled or non-labelled globulins was monitored by confocal microscopy and fluorescence measurement. Our results suggest that the internalization of vicilins is due to receptor-mediated endocytosis. Here we report the identity of a microvillar vicilin-binding protein that was purified using affinity chromatography on a vicilin-sepharose column. The putative vicilin receptor showed high homology to proteins with the CRAL-TRIO domain, specifically the Sec14 superfamily member α-tocopherol transfer protein. The precise mechanism involved in vicilin internalization was defined through the use of specific inhibitors of the endocytosis pathway. The inhibitors filipin III and nystatin significantly inhibited the endocytosis of vicilin, while chlorpromazine and phenylarsine oxide had a much lower effect on endocytosis, suggesting that the endocytic pathway is predominantly mediated by caveolin.
Assuntos
Proteínas de Transporte/metabolismo , Besouros/metabolismo , Células Epiteliais/metabolismo , Proteínas de Insetos/metabolismo , Larva/metabolismo , Proteínas de Armazenamento de Sementes/metabolismo , Sequência de Aminoácidos , Animais , Arsenicais/farmacologia , Transporte Biológico , Proteínas de Transporte/genética , Clorpromazina/farmacologia , Besouros/efeitos dos fármacos , Besouros/genética , Sistema Digestório/efeitos dos fármacos , Sistema Digestório/metabolismo , Sistema Digestório/ultraestrutura , Endocitose/efeitos dos fármacos , Endocitose/genética , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/ultraestrutura , Filipina/farmacologia , Fluoresceína-5-Isotiocianato/química , Corantes Fluorescentes/química , Expressão Gênica , Proteínas de Insetos/genética , Larva/efeitos dos fármacos , Larva/genética , Nistatina/farmacologia , Proteínas de Armazenamento de Sementes/genética , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Coloração e RotulagemRESUMO
Realgar is a naturally occurring arsenic sulfide (or Xionghuang, in Chinese). It contains over 90% tetra-arsenic tetra-sulfide (As4S4). Currently, realgar has been confirmed the antitumor activities, both in vitro and in vivo, of realgar extracted using Acidithiobacillus ferrooxidans (A. ferrooxidans). Bioleaching, a new technology to greatly improve the use rate of arsenic extraction from realgar using bacteria, is a novel methodology that addressed a limitation of the traditional method for realgar preparation. The present systematic review reports on the research progress in realgar bioleaching and its antitumor mechanism as an anticancer agent. A total of 93 research articles that report on the biological activity of extracts from realgar using bacteria and its preparation were presented in this review. The realgar bioleaching solution (RBS) works by inducing apoptosis when it is used to treat tumor cells in vitro and in vivo. When it is used to treat animal model organisms in vivo, such as mice and Caenorhabditis elegans, tumor tissues grew more slowly, with mass necrosis. Meanwhile, the agent also showed obvious inhibition of tumor cell growth. Bioleaching technology greatly improves the utilization of realgar and is a novel methodology to improve the traditional method.
Assuntos
Acidithiobacillus thiooxidans/metabolismo , Antineoplásicos/farmacologia , Arsenicais/farmacologia , Sulfetos/farmacologia , Antineoplásicos/química , Apoptose/efeitos dos fármacos , Arsenicais/química , Arsenicais/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sinergismo Farmacológico , Humanos , Células K562 , Sulfetos/química , Sulfetos/metabolismo , Fenômenos ToxicológicosRESUMO
Recent innovations in the genomic understanding of medulloblastomas have provided new ways to explore this highly invasive malignant brain cancer arising from the cerebellum. Among the four different medulloblastoma subgroups described to date, the sonic hedgehog (SHH) genetic pathway is the pathway activated in the tumorigenesis of medulloblastoma. SHH-related medulloblastomas are usually of nodular/desmoplastic histology and frequently occur in children under the age of three, an age group highly susceptible to the acute and long-term effects of treatment. Several new drugs aimed at SHH modulation are currently under development. This review focuses on the role of arsenic trioxide, a drug well established in clinical practice and probably an under-explored agent in medulloblastoma management, in the SHH pathway.
Assuntos
Antineoplásicos/administração & dosagem , Arsenicais/administração & dosagem , Neoplasias Cerebelares/tratamento farmacológico , Proteínas Hedgehog/metabolismo , Meduloblastoma/tratamento farmacológico , Óxidos/administração & dosagem , Adolescente , Antineoplásicos/farmacologia , Trióxido de Arsênio , Arsenicais/farmacologia , Neoplasias Cerebelares/metabolismo , Criança , Pré-Escolar , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Lactente , Meduloblastoma/metabolismo , Óxidos/farmacologia , Transdução de Sinais/efeitos dos fármacosRESUMO
Realgar is a naturally occurring arsenic sulfide (or Xionghuang, in Chinese). It contains over 90% tetra-arsenic tetrasulfide (As4S4). Currently, realgar has been confirmed the antitumor activities, both in vitro and in vivo, of realgar extracted using Acidithiobacillus ferrooxidans (A. ferrooxidans). Bioleaching, a new technology to greatly improve the use rate of arsenic extraction from realgar using bacteria, is a novel methodology that addressed a limitation of the traditional method for realgar preparation. The present systematic review reports on the research progress in realgar bioleaching and its antitumor mechanism as an anticancer agent. A total of 93 research articles that report on the biological activity of extracts from realgar using bacteria and its preparation were presented in this review. The realgar bioleaching solution (RBS) works by inducing apoptosis when it is used to treat tumor cells in vitro and in vivo. When it is used to treat animal model organisms in vivo, such as mice and Caenorhabditis elegans, tumor tissues grew more slowly, with mass necrosis. Meanwhile, the agent also showed obvious inhibition of tumor cell growth. Bioleaching technology greatly improves the utilization of realgar and is a novel methodology to improve the traditional method.
Assuntos
Humanos , Arsenicais/farmacologia , Sulfetos/farmacologia , Acidithiobacillus thiooxidans/metabolismo , Antineoplásicos/farmacologia , Arsenicais/metabolismo , Arsenicais/química , Sulfetos/metabolismo , Sulfetos/química , Apoptose/efeitos dos fármacos , Células K562 , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sinergismo Farmacológico , Fenômenos Toxicológicos , Antineoplásicos/químicaRESUMO
O conceito de recovery tem sido descrito em artigos como um estado de recuperação ou restabelecimento de funções psíquicas, físicas e sociais no funcionamento cotidiano. O objetivo do artigo é analisar concepções terminológicas em diferentes metodologias investigativas e a evolução paradigmática da noção de recovery. Pesquisa bibliográfica sistemática na base Pubmed com as palavras "recovery + schizophrenia", limitada a dois anos retrospectivos e a artigos completos gratuitos. Dezenove artigos foram analisados. A maioria destes busca associações entre dada característica e recovery, poucos são aqueles que discutem a sua concepção de forma que se distinga de termos comuns como "cura" e "reabilitação". Recovery como um estado em que o portador de transtorno mental grave possa sentir-se criador de seus caminhos tende a estar presente em estudos com metodologia qualitativa e em revisões bibliográficas, em que a medida de recovery deixa de relacionar-se à ausência de sintomas e passa a priorizar o quão participativa pode ser a vida de um indivíduo apesar da doença. Alguns estudos quantitativos vislumbram essa diferença conceitual. Em pesquisas qualitativas ocorre expansão na concepção de recovery e nas formas de promovê-lo.
The concept of recovery has been described in papers as a state of psychic, physical and social recuperation of day-to-day functions. The scope of this article is to analyze the concepts of the term in different research methodologies and the paradigmatic evolution of the recovery concept. Systematic bibliographical research was conducted in the Pubmed database using the words "recovery + schizophrenia" limited to freely available full papers published in the previous two years. Nineteen papers were analyzed. The majority of the papers sought associations between characteristic data and recovery; few papers discussed the concept in a way to distinguish it from other words like cure or rehabilitation. Recovery as a state in which people with severe mental illness can feel like the creators of their own itinerary tend to be found in qualitative studies and in bibliographic reviews in which the meaning of recovery is not related to the lack of symptoms and tends to prioritize how participative the life of an individual can be despite the disease. Some quantitative studies detect this conceptual difference. In qualitative research there is an increase in the concept of recovery and in ways of promoting it.