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1.
Haematologica ; 109(8): 2606-2618, 2024 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-38385272

RESUMO

Multiple myeloma (MM) remains incurable due to disease relapse and drug resistance. Notch signals from the tumor microenvironment (TME) confer chemoresistance, but the cellular and molecular mechanisms are not entirely understood. Using clinical and transcriptomic datasets, we found that NOTCH3 is upregulated in CD138+ cells from newly diagnosed MM (NDMM) patients compared to healthy individuals and increased in progression/relapsed MM (PRMM) patients. Further, NDMM patients with high NOTCH3 expression exhibited worse responses to bortezomib (BOR)-based therapies. Cells of the TME, including osteocytes, upregulated NOTCH3 in MM cells and protected them from apoptosis induced by BOR. NOTCH3 activation (NOTCH3OE) in MM cells decreased BOR anti-MM efficacy and its ability to improve survival in in vivo myeloma models. Molecular analyses revealed that NDMM and PRMM patients with high NOTCH3 exhibit CXCL12 upregulation. TME cells upregulated CXCL12 and activated the CXCR4 pathway in MM cells in a NOTCH3-dependent manner. Moreover, genetic or pharmacologic inhibition of CXCL12 in NOTCH3OE MM cells restored sensitivity to BOR regimes in vitro and in human bones bearing NOTCH3OE MM tumors cultured ex vivo. Our clinical and preclinical data unravel a novel NOTCH3-CXCL12 pro-survival signaling axis in the TME and suggest that osteocytes transmit chemoresistance signals to MM cells.


Assuntos
Quimiocina CXCL12 , Resistencia a Medicamentos Antineoplásicos , Mieloma Múltiplo , Receptor Notch3 , Transdução de Sinais , Microambiente Tumoral , Animais , Humanos , Camundongos , Bortezomib/farmacologia , Bortezomib/uso terapêutico , Linhagem Celular Tumoral , Quimiocina CXCL12/metabolismo , Quimiocina CXCL12/genética , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Mieloma Múltiplo/tratamento farmacológico , Mieloma Múltiplo/metabolismo , Mieloma Múltiplo/patologia , Mieloma Múltiplo/genética , Receptor Notch3/metabolismo , Receptor Notch3/genética , Transdução de Sinais/efeitos dos fármacos
2.
Anal Biochem ; 458: 58-60, 2014 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-24780222

RESUMO

In this work we evaluate the interaction of two optogenetic protein variants (CIB1, CIBN) with their complementary protein CRY2 by single-molecule tools in cell-free extracts. After validating the blue light induced co-localization of CRY2 and CIB1/N by Förster resonance energy transfer (FRET) in live cells, a fluorescence correlation spectroscopy (FCS) based method was developed to quantitatively determine the in vitro association of the extracted proteins. Our experiments suggest that CIB1, in comparison with CIBN, possesses a better coupling efficiency with CRY2 due to its intact protein structure and lower diffusion rate within 300s detection window.


Assuntos
Proteínas de Arabidopsis/análise , Fatores de Transcrição Hélice-Alça-Hélice Básicos/análise , Criptocromos/análise , Transferência Ressonante de Energia de Fluorescência , Microscopia Eletrônica de Varredura , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Criptocromos/genética , Criptocromos/metabolismo , Células HeLa , Humanos , Proteínas Luminescentes/genética , Proteínas Luminescentes/metabolismo , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Proteína Vermelha Fluorescente
3.
Toxicol Sci ; 199(2): 289-300, 2024 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-38518092

RESUMO

Trichloroethylene (TCE) is an industrial solvent and widespread environmental contaminant associated with CD4+ T-cell activation and autoimmune disease. Prior studies showed that exposure to TCE in the drinking water of autoimmune-prone mice expanded effector/memory CD4+ T cells with an interferon-γ (IFN-γ)-secreting Th1-like phenotype. However, very little is known how TCE exposure skews CD4+ T cells towards this pro-inflammatory Th1 subset. As observed previously, TCE exposure was associated with hypermethylation of regions of the genome related to transcriptional repression in purified effector/memory CD4 T cells. We hypothesized that TCE modulates transcriptional and/or epigenetic programming of CD4+ T cells as they differentiate from a naive to effector phenotype. In the current study, purified naive CD4 T cells from both male and female autoimmune-prone MRL/MpJ mice were activated ex vivo and polarized towards a Th1 subset for 4 days in the presence or absence of the oxidative metabolite of TCE, trichloroacetaldehyde hydrate (TCAH) in vitro. An RNA-seq assessment and reduced representation bisulfite sequencing for DNA methylation were conducted on Th1 cells or activated, non-polarized cells. The results demonstrated TCAH's ability to regulate key genes involved in the immune response and autoimmunity, including Ifng, by altering the level of DNA methylation at the gene promoter. Intriguing sex differences were observed and for the most part, the effects were more robust in females compared to males. In conclusion, TCE via TCAH epigenetically regulates gene expression in CD4+ T cells. These results may have implications for mechanistic understanding or future therapeutics for autoimmunity.


Assuntos
Metilação de DNA , Células Th1 , Tricloroetileno , Animais , Tricloroetileno/toxicidade , Metilação de DNA/efeitos dos fármacos , Células Th1/efeitos dos fármacos , Células Th1/imunologia , Células Th1/metabolismo , Feminino , Masculino , Camundongos , Linfócitos T CD4-Positivos/efeitos dos fármacos , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Camundongos Endogâmicos MRL lpr , Regulação da Expressão Gênica/efeitos dos fármacos , Interferon gama/metabolismo , Doenças Autoimunes/imunologia , Doenças Autoimunes/induzido quimicamente , Doenças Autoimunes/genética , Epigênese Genética/efeitos dos fármacos , Autoimunidade/efeitos dos fármacos
4.
J Environ Sci Health B ; 48(7): 559-69, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23581688

RESUMO

This is a report of an experimental study on a nanoencapsulation of the organophosphate acephate. Acephate was encapsulated in polyethylene glycol, using a simple, easy-to-replicate method that required no special equipment or conditions. The nanoencapsulation (nanoacephate) was characterized and its bioefficacy as compared to the regular commercial acephate was tested. The biosafety of the new compound was also tested on a murine model. Our new nanoencapsulation scored over the regular variety on all counts. It was found to successfully incorporate the active pesticidal component, acephate and this compound retained greater functional integrity over time as a nanoencapsulation. It was significantly more efficacious than the regular variety. It was biosafe when tested on murine model. We have reason to believe that this nanoencapsulation would allow the use of an organophosphate in a more targeted manner, thereby making it a cost-effective and eco-friendly alternative to the regular variety in use now.


Assuntos
Portadores de Fármacos/química , Inseticidas/toxicidade , Nanopartículas/química , Neurotoxinas/farmacologia , Organofosfatos/toxicidade , Compostos Organotiofosforados/toxicidade , Fosforamidas/toxicidade , Animais , Bioensaio , Química Farmacêutica , Feminino , Insetos/efeitos dos fármacos , Insetos/fisiologia , Inseticidas/química , Camundongos , Neurotoxinas/química , Organofosfatos/química , Compostos Organotiofosforados/química , Fosforamidas/química , Polietilenoglicóis/química
5.
J Antimicrob Chemother ; 67(5): 1134-7, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22269475

RESUMO

OBJECTIVES: To elucidate the antibacterial efficacy of chemically synthesized and custom-made sulphur nanoparticles (SNPs) of two different sizes and surface modifications against a number of multidrug-resistant Gram-negative bacilli (GNB) harbouring the New Delhi metallo-ß-lactamase 1 enzyme (NDM-1). METHODS: Antimicrobial susceptibility of the isolates was determined. The strains were evaluated for the presence of carbapenemases, ß-lactamases, 16S rRNA methylases and integrons. Chemically synthesized, polyethylene-glycol (PEG)-stabilized SNPs of 10 nm and custom-made non-capped SNPs of 60 nm were physicochemically characterized and evaluated for their antibacterial efficacy against multidrug-resistant GNB using the agar dilution method (ADM) and the broth microdilution method (BMD). The cytotoxicity of the chemically synthesized SNPs was evaluated with a human-derived hepatoma (HepG2) cell line using a WST-1 assay kit. RESULTS: All isolates were multidrug-resistant and possessed NDM-1 along with other ß-lactamases, 16S rRNA methylases and integron 1. Chemically synthesized PEGylated SNPs showed a bactericidal effect against all tested strains at a concentration between 9.41 and 18.82 mg/L using BMD. The ADM data revealed that SNPs had uniform MICs (18.82 mg/L) for all tested strains. On the other hand, custom-made SNPs failed to impart any antibacterial effect at the equivalent concentrations of chemically synthesized SNPs. The WST-1 assay revealed no significant cytotoxicity of the PEGylated SNPs even at the highest concentration (94.08 mg/L). CONCLUSIONS: To the best of our knowledge, this is the first attempted study to show the effectiveness of nanoparticles against multidrug-resistant GNB harbouring NDM-1.


Assuntos
Anti-Infecciosos/farmacologia , Farmacorresistência Bacteriana Múltipla , Bactérias Gram-Negativas/efeitos dos fármacos , Nanopartículas/química , Polietilenoglicóis/farmacologia , Enxofre/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Genes Bacterianos , Bactérias Gram-Negativas/enzimologia , Hepatócitos/efeitos dos fármacos , Humanos , Testes de Sensibilidade Microbiana , Polietilenoglicóis/toxicidade , Enxofre/toxicidade , beta-Lactamases/metabolismo
6.
Appl Microbiol Biotechnol ; 90(2): 733-43, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21350853

RESUMO

Surface-modified sulfur nanoparticles (SNPs) of two different sizes were prepared via a modified liquid-phase precipitation method, using sodium polysulfide and ammonium polysulfide as starting material and polyethylene glycol-400 (PEG-400) as the surface stabilizing agent. Surface topology, size distribution, surface modification of SNPs with PEG-400, quantitative analysis for the presence of sulfur in nanoformulations, and thermal stability of SNPs were determined by atomic force microscopy (AFM), dynamic light scattering (DLS) plus high-resolution transmission electron microscopy (HR-TEM), fourier transform infrared (FT-IR) spectroscopy, energy dispersive X-ray (EDX) spectroscopy, and thermogravimetric analysis (TGA), respectively. A simultaneous study with micron-sized sulfur (S(0)) and SNPs was carried out to evaluate their fungicidal efficacy against Aspergillus niger and Fusarium oxysporum in terms of radial growth, sporulation, ultrastructural modifications, and phospholipid content of the fungal strains using a modified poisoned food technique, spore-germination slide bioassay, environmental scanning electron microscopy (ESEM), and spectrometry. SNPs expressed promising inhibitory effect on fungal growth and sporulation and also significantly reduced phospholipid content.


Assuntos
Antifúngicos/farmacologia , Aspergillus niger/efeitos dos fármacos , Fusarium/efeitos dos fármacos , Nanopartículas/química , Enxofre/química , Análise de Variância , Antifúngicos/química , Aspergillus niger/crescimento & desenvolvimento , Aspergillus niger/isolamento & purificação , Aspergillus niger/ultraestrutura , Fusarium/crescimento & desenvolvimento , Fusarium/isolamento & purificação , Fusarium/ultraestrutura , Microscopia de Força Atômica , Microscopia Eletrônica de Varredura , Tamanho da Partícula , Polietilenoglicóis/química , Espectrometria por Raios X , Espectroscopia de Infravermelho com Transformada de Fourier , Termogravimetria
7.
Curr Microbiol ; 62(3): 715-26, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20936471

RESUMO

Despite discovery of the pathogen more than 100 years ago, tuberculosis (TB) continues to be a major killer disease worldwide. Currently a third of world population is infected and multiple-drug-resistant (mdr) TB registers maximum mortality by a single pathogen. Nanomedicine provides enormous opportunity for developing novel drugs. We have recently demonstrated surface-modified-lipophilic-nanosilica as drug to combat malaria and 100% lethal virus, BmNPV. Nanosilver possesses inherent antibacterial properties, but toxicity is a major concern. We hypothesized that capping with nature-inspired biomolecules, bovine serum albumin (BSA) and Poly-n-vinyl-pyrrolidone (PVP) used as blood volume extender, might insure biosafety. BSA-nano-Ag was found to be more stable than PVP-nano-Ag at physiological pH. In this first ever study on clinical isolates collected from TB endemic areas, we report, BSA-nano-Ag act as potent anti-TB drug. Further study with (human serum albumin)-nano-Ag and core-shell-nano-Ag could increase the biocompatibility of oral TB drug formulations without compromising on the efficacy of the drug.


Assuntos
Antituberculosos/farmacologia , Farmacorresistência Bacteriana Múltipla , Mycobacterium tuberculosis/efeitos dos fármacos , Nanopartículas/microbiologia , Prata/farmacologia , Estabilidade de Medicamentos , Humanos , Concentração de Íons de Hidrogênio , Mycobacterium tuberculosis/isolamento & purificação , Tuberculose Resistente a Múltiplos Medicamentos/microbiologia
8.
Cells ; 10(10)2021 10 02.
Artigo em Inglês | MEDLINE | ID: mdl-34685612

RESUMO

Conventional wisdom is that Sprouty2 (SPRY2), a suppressor of Receptor Tyrosine Kinase (RTK) signaling, functions as a tumor suppressor and is downregulated in many solid tumors. We reported, for the first time, that increased expression of SPRY2 augments cancer phenotype and Epithelial-Mesenchymal-Transition (EMT) in colorectal cancer (CRC). In this report, we assessed epigenetic DNA modifications that regulate SPRY2 expression in CRC. A total of 4 loci within SPRY2 were evaluated for 5mC using Combined Bisulfite Restriction Analysis (COBRA). Previously sequenced 5hmC nano-hmC seal data within SPRY2 promoter and gene body were evaluated in CRC. Combined bioinformatics analyses of SPRY2 CRC transcripts by RNA-seq/microarray and 450K methyl-array data archived in The Cancer Genome Atlas (TCGA) and GEO database were performed. SPRY2 protein in CRC tumors and cells was measured by Western blotting. Increased SPRY2 mRNA was observed across several CRC datasets and increased protein expression was observed among CRC patient samples. For the first time, SPRY2 hypomethylation was identified in adenocarcinomas in the promoter and gene body. We also revealed, for the first time, increases of 5hmC deposition in the promoter region of SPRY2 in CRC. SPRY2 promoter hypomethylation and increased 5hmC may play an influential role in upregulating SPRY2 in CRC.


Assuntos
Neoplasias Colorretais/genética , Epigênese Genética , Peptídeos e Proteínas de Sinalização Intracelular/genética , Proteínas de Membrana/genética , Regulação para Cima/genética , 5-Metilcitosina/metabolismo , Adenoma/genética , Sítios de Ligação/genética , Fator de Ligação a CCCTC/metabolismo , Linhagem Celular Tumoral , Metilação de DNA/genética , Regulação Neoplásica da Expressão Gênica , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas de Membrana/metabolismo , Regiões Promotoras Genéticas , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Transcrição Gênica
9.
J Hematol Oncol ; 13(1): 108, 2020 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-32762714

RESUMO

BACKGROUND: Multiple Myeloma (MM) is a hematological malignancy with genomic heterogeneity and poor survival outcome. Apart from the central role of genetic lesions, epigenetic anomalies have been identified as drivers in the development of the disease. METHODS: Alterations in the DNA methylome were mapped in 52 newly diagnosed MM (NDMM) patients of six molecular subgroups and matched with loci-specific chromatin marks to define their impact on gene expression. Differential DNA methylation analysis was performed using DMAP with a ≥10% increase (hypermethylation) or decrease (hypomethylation) in NDMM subgroups, compared to control samples, considered significant for all the subsequent analyses with p<0.05 after adjusting for a false discovery rate. RESULTS: We identified differentially methylated regions (DMRs) within the etiological cytogenetic subgroups of myeloma, compared to control plasma cells. Using gene expression data we identified genes that are dysregulated and correlate with DNA methylation levels, indicating a role for DNA methylation in their transcriptional control. We demonstrated that 70% of DMRs in the MM epigenome were hypomethylated and overlapped with repressive H3K27me3. In contrast, differentially expressed genes containing hypermethylated DMRs within the gene body or hypomethylated DMRs at the promoters overlapped with H3K4me1, H3K4me3, or H3K36me3 marks. Additionally, enrichment of BRD4 or MED1 at the H3K27ac enriched DMRs functioned as super-enhancers (SE), controlling the overexpression of genes or gene-cassettes. CONCLUSIONS: Therefore, this study presents the underlying epigenetic regulatory networks of gene expression dysregulation in NDMM patients and identifies potential targets for future therapies.


Assuntos
Epigênese Genética , Epigenoma , Regulação Neoplásica da Expressão Gênica , Redes Reguladoras de Genes/genética , Mieloma Múltiplo/genética , Aneuploidia , Cromossomos Humanos Par 11/genética , Cromossomos Humanos Par 11/ultraestrutura , Cromossomos Humanos Par 14/genética , Cromossomos Humanos Par 14/ultraestrutura , Cromossomos Humanos Par 4/genética , Cromossomos Humanos Par 4/ultraestrutura , Ciclina D1/biossíntese , Ciclina D1/genética , Ciclina D2/biossíntese , Ciclina D2/genética , Metilação de DNA , DNA de Neoplasias/genética , DNA de Neoplasias/metabolismo , Perfilação da Expressão Gênica , Ontologia Genética , Código das Histonas , Histonas/metabolismo , Humanos , Mieloma Múltiplo/classificação , Proteínas de Neoplasias/biossíntese , Proteínas de Neoplasias/genética , Plasmócitos/metabolismo , Regiões Promotoras Genéticas , Proteínas Proto-Oncogênicas c-maf/genética , Translocação Genética
10.
Blood Cancer J ; 10(6): 70, 2020 06 19.
Artigo em Inglês | MEDLINE | ID: mdl-32555163

RESUMO

Primary plasma cell leukemia (pPCL) is a rare and aggressive form of multiple myeloma (MM) that is characterized by the presence of ≥20% circulating plasma cells. Overall survival remains poor despite advances of anti-MM therapy. The disease biology as well as molecular mechanisms that distinguish pPCL from non-pPCL MM remain poorly understood and, given the rarity of the disease, are challenging to study. In an attempt to identify key biological mechanisms that result in the aggressive pPCL phenotype, we performed whole-exome sequencing and gene expression analysis in 23 and 41 patients with newly diagnosed pPCL, respectively. The results reveal an enrichment of complex structural changes and high-risk mutational patterns in pPCL that explain, at least in part, the aggressive nature of the disease. In particular, pPCL patients with traditional low-risk features such as translocation t(11;14) or hyperdiploidy accumulated adverse risk genetic events that could account for the poor outcome in this group. Furthermore, gene expression profiling showed upregulation of adverse risk modifiers in pPCL compared to non-pPCL MM, while adhesion molecules and extracellular matrix proteins became increasingly downregulated. In conclusion, this is one of the largest studies to dissect pPCL on a genomic and molecular level.


Assuntos
Leucemia Plasmocitária/genética , Mutação , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Perfilação da Expressão Gênica , Regulação Leucêmica da Expressão Gênica , Genômica , Humanos , Leucemia Plasmocitária/patologia , Masculino , Pessoa de Meia-Idade , Taxa de Mutação , Transcriptoma , Translocação Genética , Sequenciamento do Exoma
11.
Cancer Res ; 80(21): 4707-4719, 2020 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-33004350

RESUMO

T-cell exhaustion in cancer is linked to poor clinical outcomes, where evidence suggests T-cell metabolic changes precede functional exhaustion. Direct competition between tumor-infiltrating lymphocytes (TIL) and cancer cells for metabolic resources often renders T cells dysfunctional. Environmental stress produces epigenome remodeling events within TIL resulting from loss of the histone methyltransferase EZH2. Here, we report an epigenetic mechanism contributing to the development of metabolic exhaustion in TIL. A multiomics approach revealed a Cdkn2a.Arf-mediated, p53-independent mechanism by which EZH2 inhibition leads to mitochondrial dysfunction and the resultant exhaustion. Reprogramming T cells to express a gain-of-function EZH2 mutant resulted in an enhanced ability of T cells to inhibit tumor growth in vitro and in vivo. Our data suggest that manipulation of T-cell EZH2 within the context of cellular therapies may yield lymphocytes that are able to withstand harsh tumor metabolic environments and collateral pharmacologic insults. SIGNIFICANCE: These findings demonstrate that manipulation of T-cell EZH2 in cellular therapies may yield cellular products able to withstand solid tumor metabolic-deficient environments. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/21/4707/F1.large.jpg.


Assuntos
Inibidor p16 de Quinase Dependente de Ciclina/metabolismo , Proteína Potenciadora do Homólogo 2 de Zeste/metabolismo , Linfócitos do Interstício Tumoral/metabolismo , Neoplasias Experimentais/imunologia , Animais , Linhagem Celular Tumoral , Epigênese Genética/fisiologia , Camundongos , Microambiente Tumoral/imunologia
12.
Methods Mol Biol ; 1792: 179-191, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29797260

RESUMO

Reduced representation bisulfite sequencing (RRBS) is one of the most comprehensive yet economic ways of mapping whole genome DNA-methylation. Here, we have substantially modified the RRBS protocol by combining end-repair and A-tailing steps, and by introducing a bead-based method for rapid and easy size selection of the library molecules. The method has been optimized for myeloma clinical samples, where the input DNA concentration can be as low as 100 ng. The method developed can be accomplished in 3 days, including the initial overnight MspI enzyme digestion. Although the protocol has been optimized in myeloma samples, it is broadly applicable to any clinical sample, which is restricted by very low input DNA concentrations.


Assuntos
Mieloma Múltiplo/genética , Análise de Sequência de DNA , Ilhas de CpG , Código de Barras de DNA Taxonômico , Metilação de DNA , Biblioteca Gênica , Genômica/métodos , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Controle de Qualidade , Análise de Sequência de DNA/métodos
13.
Sci Rep ; 7: 42047, 2017 02 09.
Artigo em Inglês | MEDLINE | ID: mdl-28181538

RESUMO

Enzymes involved in epigenetic processes such as methyltransferases or demethylases are becoming highly utilized for their persistent DNA or histone modifying efficacy. Herein, we have developed an optogenetic toolbox fused to the catalytic domain (CD) of DNA-methyltransferase3A (DNMT3A-CD) or Ten-Eleven Dioxygenase-1 (TET1-CD) for loci-specific alteration of the methylation state at the promoter of Ascl1 (Mash1), a candidate proneuron gene. Optogenetical protein pairs, CRY2 linked to DNMT3A-CD or TET1-CD and CIB1 fused to a Transcription Activator-Like Element (TALE) locating an Ascl1 promoter region, were designed for site specific epigenetic editing. A differentially methylated region at the Ascl1 promoter, isolated from murine dorsal root ganglion (hypermethylated) and striated cells (hypomethylated), was targeted with these optogenetic-epigenetic constructs. Optimized blue-light illumination triggered the co-localization of TALE constructs with DNMT3A-CD or TET1-CD fusion proteins at the targeted site of the Ascl1 promoter. We found that this spatiotemporal association of the fusion proteins selectively alters the methylation state and also regulates gene activity. This proof of concept developed herein holds immense promise for the ability to regulate gene activity via epigenetic modulation with spatiotemporal precision.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/biossíntese , Epigênese Genética , Biologia Molecular/métodos , Células-Tronco Neurais , Optogenética/métodos , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Perfilação da Expressão Gênica , Luz , Camundongos , Regiões Promotoras Genéticas
14.
Toxicol Sci ; 156(1): 261-274, 2017 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-28115643

RESUMO

In this study we evaluated and correlated the cytotoxic effects of zinc oxide nanoparticles (ZnO-NPs) to the epigenetic modifications, using human embryonic kidney (HEK-293) cells as a model system. Imaging of singlet and total reactive oxygen species (ROS) in ZnO-NPs-treated live cells was performed followed by the evaluation of its effects on cytoskeletal, mitochondrial, and nuclear integrity, and on the expression of ROS responsive genes. Next, we determined the global and locus-specific changes in DNA-methylation at the 3 global genomic repeat sequences namely LINE-1, subtelomeric D4Z4 and pericentromeric NBL2, and at the promoter of selected ROS responsive genes (AOX1, HMOX1, NCF2, SOD3). Our studies revealed severe actin depolymerization, increased release of mitochondrial cytochrome C, and nuclear enlargement in ZnO-NPs-treated cells. At the epigenetic level, we observed global reduction in 5-methylcytosine and increase in 5-hydroxymethylcytosine content. Additionally, we observed significant increase in the expression of Ten-Eleven Translocation (TET)-methylcytosine dioxygenase genes but not in the expression of DNA-methyltransferases (DNMTs). Based on our findings, we suggest that ZnO-NPs induce abundant increase in ROS to promote multimodal structural and functional anomalies in cells. Most importantly, ZnO-NP-induced ROS may promote global hypomethylation in cells by triggering the expression of TET-enzymes, avoiding DNMT interferences. Global DNA demethylation is considered to be the hallmark of the majority of cancers and once acquired this could be propagated to future progenies. The present study, hence, can be used as a platform for the assessment of epigenomic toxicity of ZnO-NPs in humans in the light of its use in commercial products.


Assuntos
Desmetilação do DNA/efeitos dos fármacos , Epigênese Genética/efeitos dos fármacos , Hepatócitos/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Espécies Reativas de Oxigênio/agonistas , Óxido de Zinco/toxicidade , 5-Metilcitosina/análogos & derivados , 5-Metilcitosina/metabolismo , Citoesqueleto de Actina/efeitos dos fármacos , Carcinógenos Ambientais/química , Carcinógenos Ambientais/toxicidade , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Membrana Celular/ultraestrutura , Tamanho do Núcleo Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Células HEK293 , Hepatócitos/metabolismo , Hepatócitos/ultraestrutura , Humanos , Nanopartículas Metálicas/ultraestrutura , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Oxirredutases/genética , Oxirredutases/metabolismo , Regiões Promotoras Genéticas/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Sequências Repetitivas de Ácido Nucleico/efeitos dos fármacos , Óxido de Zinco/química
15.
Toxicol Res (Camb) ; 5(2): 641-650, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-28944004

RESUMO

The volatile, water soluble trichloroethylene (TCE) is a hazardous industrial waste and could lead to various health problems, including cancer, neuropathy, cardiovascular defects, and immune diseases. Toxicological studies taking use of in vitro and in vivo models have been conducted to understand the biological impacts of TCE at the genetic, transcriptomic, metabolomic, and signaling levels. The epigenetic aberrations induced by TCE have also been reported in a number of model organisms, while a detailed mechanistic elucidation is lacking. In this study we uncover an unreported mechanism accounting for the epigenetic toxicity due to TCE exposure by monitoring the single-molecule dynamics of DNA methyltransferase 3a (Dnmt3a) in living cells. TCE-induced global DNA hypomethylation could be partly attributed to the disrupted Dnmt3a-DNA association. By analyzing the components of detached Dnmt3a, we found that the Dnmt3a oligomers (e.g., dimer, trimer, and high-order oligomers) dissociated from heterochromatin in a dose-dependent manner upon exposure. Thereafter the diminished DNA-binding affinity of Dnmt3a resulted in a significant decrease in 5-methylcytosine (5mC) under both acute high-dosage and chronic low-dosage TCE exposure. The resulting DNA demethylation might also be contributed by the elevated expression of ten-eleven-translocation (Tet) enzymes and reformed cysteine cycle. Besides the global effect, we further identified that a group of heterochromatin-located, cancer-related microRNAs (miRNAs) experienced promoter demethylation upon TCE exposure.

16.
Oncotarget ; 7(29): 46545-46556, 2016 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-27356740

RESUMO

DNA hypermethylation at the promoter of tumour-suppressor genes is tightly correlated with their transcriptional repression and recognized as the hallmark of majority of cancers. Epigenetic silencing of tumour suppressor genes impairs their cellular functions and activates a cascade of events driving cell transformation and cancer progression. Here, we examine site-specific and spatiotemporal alteration in DNA methylation at a target region in BRCA1 gene promoter, a model tumour suppressor gene. We have developed a programmable CRISPR-Cas9 based demethylase tool containing the deactivated Cas9 (dCas9) fused to the catalytic domain (CD) of Ten-Eleven Translocation (TET) dioxygenase1 (TET1CD). The fusion protein selectively demethylates targeted regions within BRCA1 promoter as directed by the designed single-guide RNAs (sgRNA), leading to the transcriptional up-regulation of the gene. We also noticed the increment in 5-hydroxymethylation content (5-hmC) at the target DNA site undergoing the most profound demethylation. It confirms the catalytic activity of TET1 in TET1-dCas9 fusion proteins-mediated demethylation at these target sequences. The modular design of the fusion constructs presented here allows for the selective substitution of other chromatin or DNA modifying enzymes and for loci-specific targeting to uncover epigenetic regulatory pathways at gene promoters and other selected genomic regions.


Assuntos
Sistemas CRISPR-Cas/fisiologia , Metilação de DNA , Genes BRCA1 , Oxigenases de Função Mista/genética , Regiões Promotoras Genéticas , Proteínas Proto-Oncogênicas/genética , Domínio Catalítico , Ilhas de CpG , Células HeLa , Humanos , Células MCF-7
17.
Oncotarget ; 7(31): 50380-50391, 2016 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-27391261

RESUMO

Telomere length homeostasis, critical for chromosomal integrity and genome stability, is controlled by intricate molecular regulatory machinery that includes epigenetic modifications. Here, we examine site-specific and spatiotemporal alteration of the subtelomeric methylation of CpG islands using optogenetic tools to understand the epigenetic regulatory mechanisms of telomere length maintenance. Human DNA methyltransferase3A (DNMT3A) were assembled selectively at chromosome ends by fusion to cryptochrome 2 protein (CRY2) and its interacting complement, the basic helix loop helix protein-1 (CIB1). CIB1 was fused to the telomere-associated protein telomere repeat binding factor-1 (TRF1), which localized the protein complex DNMT3A-CRY2 at telomeric regions upon excitation by blue-light monitored by single-molecule fluorescence analyses. Increased methylation was achieved selectively at subtelomeric CpG sites on the six examined chromosome ends specifically after blue-light activation, which resulted in progressive increase in telomere length over three generations of HeLa cell replications. The modular design of the fusion constructs presented here allows for the selective substitution of other chromatin modifying enzymes and for loci-specific targeting to regulate the epigenetic pathways at telomeres and other selected genomic regions of interest.


Assuntos
Ilhas de CpG , DNA (Citosina-5-)-Metiltransferases/genética , Metilação de DNA , Proteínas de Ligação ao Cálcio/metabolismo , Cromatina/química , Cromossomos/ultraestrutura , Criptocromos/metabolismo , DNA Metiltransferase 3A , Epigênese Genética , Células HeLa , Humanos , Optogenética , Domínios Proteicos , Telomerase/genética , Telômero/ultraestrutura , Homeostase do Telômero , Proteína 1 de Ligação a Repetições Teloméricas/metabolismo
18.
Clin Epigenetics ; 7: 107, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26451167

RESUMO

BACKGROUND: Subtelomeric regions dynamically change their epigenetic pattern during development and progression of several malignancies and degenerative disorders. However, DNA methylation of human subtelomeres and their correlation to telomere length (TL) remain undetermined in glioma. RESULTS: Herein, we report on the selective changes in subtelomeric DNA methylation at the end of five chromosomes (Chr.) (7q, 8q. 18p, 21q, and XpYp) and ascertain their correlation with TL in patients with glioma. Subtelomeric methylation level was invariably higher in glioma patients compared to the control group, irrespective of their age and tumor grade. In particular, a significant increase in methylation was observed at the subtelomeric CpG sites of Chr. 8q, 21q, and XpYp in tissues, obtained from the brain tumor of glioma patients. In contrast, no significant change in methylation was observed at the subtelomere of Chr. 7q and 18p. Selective changes in the subtelomeric methylation level, however, did not show any significant correlation to the global TL. This observed phenomenon was validated in vitro by inducing demethylation in a glioblastoma cell line (SF-767) using 5-azacytidine (AZA) treatment. AZA treatment caused significant changes in the subtelomeric methylation pattern but did not alter the TL, which supports our hypothesis. CONCLUSIONS: DNA methylation level dramatically increased at the subtelomere of Chr.8q, 21q, and XpYp in malignant glioma, which could be used as an early epigenetic diagnostic biomarker of the disease. Alterations in subtelomeric methylation, however, have no effects on the TL.

19.
Sci Rep ; 5: 9281, 2015 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-25901663

RESUMO

The USFDA approved "epigenetic drug", Decitabine, exerts its effect by hypomethylating DNA, demonstrating the pivotal role aberrant genome-wide DNA methylation patterns play in cancer ontology. Using sensitive technologies in a cellular model of Acute Myeloid Leukemia, we demonstrate that while Decitabine reduces the global levels of 5-methylcytosine (5mC), it results in paradoxical increase of 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC) and 5-carboxylcytosine (5caC) levels. Hitherto, the only biological mechanism known to generate 5hmC, 5fC and 5caC, involving oxidation of 5mC by members of Ten-Eleven-Translocation (TET) dioxygenase family, was not observed to undergo any alteration during DAC treatment. Using a multi-compartmental model of DNA methylation, we show that partial selectivity of TET enzymes for hemi-methylated CpG dinucleotides could lead to such alterations in 5hmC content. Furthermore, we investigated the binding of TET1-catalytic domain (CD)-GFP to DNA by Fluorescent Correlation Spectroscopy in live cells and detected the gradual increase of the DNA bound fraction of TET1-CD-GFP after treatment with Decitabine. Our study provides novel insights on the therapeutic activity of DAC in the backdrop of the newly discovered derivatives of 5mC and suggests that 5hmC has the potential to serve as a biomarker for monitoring the clinical success of patients receiving DAC.


Assuntos
Azacitidina/análogos & derivados , Citosina/análogos & derivados , 5-Metilcitosina/química , Azacitidina/química , Domínio Catalítico , Cromatografia Líquida de Alta Pressão , Ilhas de CpG , Citosina/análise , Citosina/química , Citosina/metabolismo , DNA (Citosina-5-)-Metiltransferases/metabolismo , Metilação de DNA , Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/metabolismo , Decitabina , Ensaio de Imunoadsorção Enzimática , Células HL-60 , Humanos , Imuno-Histoquímica , Leucemia Mieloide Aguda/metabolismo , Leucemia Mieloide Aguda/patologia , Células MCF-7 , Microscopia de Fluorescência , Oxigenases de Função Mista , Ligação Proteica , Proteínas Proto-Oncogênicas/química , Proteínas Proto-Oncogênicas/metabolismo , Espectrometria de Fluorescência , Espectrometria de Massas em Tandem
20.
Environ Toxicol Pharmacol ; 36(2): 675-679, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23892072

RESUMO

A comprehensive pharmacokinetic profiling of novel drugs and therapeutics is a definite prerequisite of drug discovery and development. The present study expedites the in vivo and in vitro pharmacokinetic properties of colloidal sulfur nanoparticles (SNPs). In vitro dissolution properties of SNPs have been demonstrated and compared with the in vivo pharmacokinetic parameters of rabbit (Oryctolagus cuniculus) serum sample. The present study was also aimed at developing levels of correlation between in vitro and in vivo pharmacokinetic parameters. Cumulative results of the proposed study also suggest good in vitro-in vivo correlation of these novel nanocolloids and suggest their immediate profiling as an antimicrobial drug.


Assuntos
Anti-Infecciosos/farmacocinética , Nanopartículas , Compostos de Enxofre/farmacocinética , Administração Oral , Animais , Anti-Infecciosos/administração & dosagem , Anti-Infecciosos/sangue , Anti-Infecciosos/química , Disponibilidade Biológica , Química Farmacêutica , Coloides , Feminino , Modelos Biológicos , Coelhos , Solubilidade , Compostos de Enxofre/administração & dosagem , Compostos de Enxofre/sangue , Compostos de Enxofre/química , Tecnologia Farmacêutica/métodos
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