RESUMO
Emerging studies support that the polycomb repressive complex 2 (PRC2) regulates phenotypic changes of carcinoma cells by modulating their shifts among metastable states within the epithelial and mesenchymal spectrum. This new role of PRC2 in cancer has been recently proposed to stem from the ability of its catalytic subunit EZH2 to bind and modulate the transcription of mesenchymal genes during epithelial-mesenchymal transition (EMT) in lung cancer cells. Here, we asked whether this mechanism is conserved in other types of carcinomas. By combining TGF-ß-mediated reversible induction of epithelial to mesenchymal transition and inhibition of EZH2 methyltransferase activity, we demonstrate that EZH2 represses a large set of mesenchymal genes and favours the residence of breast cancer cells towards the more epithelial spectrum during EMT. In agreement, analysis of human patient samples supports that EZH2 is required to efficiently repress mesenchymal genes in breast cancer tumours. Our results indicate that PRC2 operates through similar mechanisms in breast and lung cancer cells. We propose that PRC2-mediated direct transcriptional modulation of the mesenchymal gene expression programme is a conserved molecular mechanism underlying cell dissemination across human carcinomas.
Assuntos
Neoplasias da Mama , Proteína Potenciadora do Homólogo 2 de Zeste , Transição Epitelial-Mesenquimal , Regulação Neoplásica da Expressão Gênica , Humanos , Proteína Potenciadora do Homólogo 2 de Zeste/metabolismo , Proteína Potenciadora do Homólogo 2 de Zeste/genética , Transição Epitelial-Mesenquimal/genética , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Neoplasias da Mama/metabolismo , Feminino , Linhagem Celular Tumoral , Fator de Crescimento Transformador beta/metabolismo , Complexo Repressor Polycomb 2/metabolismo , Complexo Repressor Polycomb 2/genética , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Neoplasias Pulmonares/metabolismoRESUMO
Chagas disease is caused by the parasite Trypanosoma cruzi and affects over 7 million people worldwide. The two actual treatments, Benznidazole (Bzn) and Nifurtimox, cause serious side effects due to their high toxicity leading to treatment abandonment by the patients. In this work, we propose DNA G-quadruplexes (G4) as potential therapeutic targets for this infectious disease. We have found 174 PQS per 100,000 nucleotides in the genome of T. cruzi and confirmed G4 formation of three frequent motifs. We synthesized a family of 14 quadruplex ligands based in the dithienylethene (DTE) scaffold and demonstrated their binding to these identified G4 sequences. Several DTE derivatives exhibited micromolar activity against epimastigotes of four different strains of T. cruzi, in the same concentration range as Bzn. Compounds L3 and L4 presented remarkable activity against trypomastigotes, the active form in blood, of T. cruzi SOL strain (IC50 = 1.5-3.3 µM, SI = 25-40.9), being around 40 times more active than Bzn and displaying much better selectivity indexes.
Assuntos
Doença de Chagas , Quadruplex G , Tripanossomicidas , Trypanosoma cruzi , Trypanosoma cruzi/efeitos dos fármacos , Quadruplex G/efeitos dos fármacos , Ligantes , Doença de Chagas/tratamento farmacológico , Tripanossomicidas/farmacologia , Tripanossomicidas/química , Tripanossomicidas/síntese química , Humanos , Estrutura Molecular , Relação Estrutura-Atividade , Relação Dose-Resposta a Droga , Testes de Sensibilidade Parasitária , Antiparasitários/farmacologia , Antiparasitários/química , Antiparasitários/síntese químicaRESUMO
Fluorescence-based probes represent a powerful tool for noninvasive imaging of living systems in real time and with a high temporal and spatial resolution. Amongst several known fluorophores, 3-difluoroborodipyrromethene (BODIPY) derivatives have become a cornerstone for innovative fluorescent labelling applications, mainly due to their advantageous features including their facile synthesis, structural versatility and exceptional photophysical properties. In this context, we report a BODIPY-based fluorescent probe for imaging of lysosomes in living cells. The BODIPY derivative displayed a remarkable fluorescence enhancement at low pH values with a pKa* of 3.1. In vitro studies by confocal microscopy in HeLa cells demonstrated that the compound was able to permeate cell membrane and selectively label lysosome whilst remaining innocuous to the cell culture at the maximum concentration tested. Herein, the BODIPY derivative holds the promise of investigating lysosomal dynamics and function in living cells through fluorescence imaging.
Assuntos
Corantes Fluorescentes , Lisossomos , Humanos , Corantes Fluorescentes/química , Células HeLa , Lisossomos/metabolismo , Concentração de Íons de HidrogênioRESUMO
In the era of antimicrobial resistance, the identification of new compounds with strong antimicrobial activity and the development of alternative therapies to fight drug-resistant bacteria are urgently needed. Here, we have used resveratrol, a safe and well-known plant-derived stilbene with poor antimicrobial properties, as a scaffold to design several new families of antimicrobials by adding different chemical entities at specific positions. We have characterized the mode of action of the most active compounds prepared and have examined their synergistic antibacterial activity in combination with traditional antibiotics. Some alkyl- and silyl-resveratrol derivatives show bactericidal activity against Gram-positive bacteria in the same low micromolar range of traditional antibiotics, with an original mechanism of action that combines membrane permeability activity with ionophore-related activities. No cross-resistance or antagonistic effect was observed with traditional antibiotics. Synergism was observed for some specific general-use antibiotics, such as aminoglycosides and cationic antimicrobial peptide antibiotics. No hemolytic activity was observed at the active concentrations or above, although some low toxicity against an MRC-5 cell line was noted.
Assuntos
Anti-Infecciosos , Bactérias Gram-Positivas , Antibacterianos/química , Antibacterianos/farmacologia , Anti-Infecciosos/farmacologia , Bactérias Gram-Negativas , Testes de Sensibilidade Microbiana , ResveratrolRESUMO
Cancer is currently a leading cause of death worldwide. The World Health Organization estimates an increase of 60% in the global cancer incidence in the next two decades. The inefficiency of the currently available therapies has prompted an urgent effort to develop new strategies that enable early diagnosis and improve response to treatment. Nanomedicine formulations can improve the pharmacokinetics and pharmacodynamics of conventional therapies and result in optimized cancer treatments. In particular, theranostic formulations aim at addressing the high heterogeneity of tumors and metastases by integrating imaging properties that enable a non-invasive and quantitative assessment of tumor targeting efficiency, drug delivery, and eventually the monitoring of the response to treatment. However, in order to exploit their full potential, the promising results observed in preclinical stages need to achieve clinical translation. Despite the significant number of available functionalization strategies, targeting efficiency is currently one of the major limitations of advanced nanomedicines in the oncology area, highlighting the need for more efficient nanoformulation designs that provide them with selectivity for precise cancer types and tumoral tissue. Under this current need, this review provides an overview of the strategies currently applied in the cancer theranostics field using magnetic nanoparticles (MNPs) and solid lipid nanoparticles (SLNs), where both nanocarriers have recently entered the clinical trials stage. The integration of these formulations into magnetic solid lipid nanoparticles-with different composition and phenotypic activity-constitutes a new generation of theranostic nanomedicines with great potential for the selective, controlled, and safe delivery of chemotherapy.
RESUMO
Glycosyl conjugation to drugs is a strategy being used to take advantage of glucose transporters (GLUT) overexpression in cancer cells in comparison with non-cancerous cells. Its extension to the conjugation of drugs to thiosugars tries to exploit their higher biostability when compared to O-glycosides. Here, we have synthesized a series of thiosugar naphthalene diimide conjugates as G-quadruplex ligands and have explored modifications of the amino sidechain comparing dimethyl amino and morpholino groups. Then, we studied their antiproliferative activity in colon cancer cells, and their antiparasitic activity in T. brucei and L. major parasites, together with their ability to bind quadruplexes and their cellular uptake and location. We observed higher toxicity for the sugar-NDI-NMe2 derivatives than for the sugar-NDI-morph compounds, both in mammalian cells and in parasites. Our experiments indicate that a less efficient binding to quadruplexes and a worse cellular uptake of the carb-NDI-morph derivatives could be the reasons for these differences. We found small variations in cytotoxicity between O-carb-NDIs and S-carb-NDIs, except against non-cancerous human fibroblasts MRC-5, where thiosugar-NDIs tend to be less toxic. This leads to a notable selectivity for ß-thiomaltosyl-NDI-NMe212 (9.8 fold), with an IC50 of 0.3 µM against HT-29 cells. Finally, the antiparasitic activity observed for the carb-NDI-NMe2 derivatives against T. brucei was in the nanomolar range with a good selectivity index in the range of 30- to 69- fold.
Assuntos
Quadruplex G , Tioaçúcares , Animais , Antiparasitários/farmacologia , Humanos , Imidas/química , Imidas/farmacologia , Ligantes , NaftalenosRESUMO
Guanidine DNA quadruplex (G4-DNA) structures convey a distinctive layer of epigenetic information that is critical for regulating key biological activities and processes as transcription, replication, and repair in living cells. The information regarding their role and use as therapeutic drug targets in bacteria is still scarce. Here, we tested the biological activity of a G4-DNA ligand library, based on the naphthalene diimide (NDI) pharmacophore, against both Gram-positive and Gram-negative bacteria. For the best compound identified, NDI-10, a different action mechanism was described for Gram-positive or negative bacteria. This asymmetric activity profile could be related to the different prevalence of putative G4-DNA structures in each group, the influence that they can exert on gene expression, and the different roles of the G4 structures in these bacteria, which seem to promote transcription in Gram-positive bacteria and repress transcription in Gram-negatives.
Assuntos
Quadruplex G , Antibacterianos/farmacologia , DNA , Bactérias Gram-Negativas , Bactérias Gram-Positivas , Imidas , Ligantes , NaftalenosRESUMO
Quadruplex structures have been identified in a plethora of organisms where they play important functions in the regulation of molecular processes, and hence have been proposed as therapeutic targets for many diseases. In this paper we report the extensive bioinformatic analysis of the SARS-CoV-2 genome and related viruses using an upgraded version of the open-source algorithm G4-iM Grinder. This version improves the functionality of the software, including an easy way to determine the potential biological features affected by the candidates found. The quadruplex definitions of the algorithm were optimized for SARS-CoV-2. Using a lax quadruplex definition ruleset, which accepts amongst other parameters two residue G- and C-tracks, 512 potential quadruplex candidates were discovered. These sequences were evaluated by their in vitro formation probability, their position in the viral RNA, their uniqueness and their conservation rates (calculated in over seventeen thousand different COVID-19 clinical cases and sequenced at different times and locations during the ongoing pandemic). These results were then compared subsequently to other Coronaviridae members, other Group IV (+)ssRNA viruses and the entire viral realm. Sequences found in common with other viral species were further analyzed and characterized. Sequences with high scores unique to the SARS-CoV-2 were studied to investigate the variations amongst similar species. Quadruplex formation of the best candidates were then confirmed experimentally. Using NMR and CD spectroscopy, we found several highly stable RNA quadruplexes that may be suitable therapeutic targets for the SARS-CoV-2.
Assuntos
Quadruplex G , Genoma Viral , Motivos de Nucleotídeos , RNA Viral/genética , SARS-CoV-2/genética , Biologia Computacional , GuaninaRESUMO
Natural phenolic compounds found in food have demonstrated interesting preventive and therapeutic effects on a large variety of pathologies. Indeed, some of them, such as resveratrol (RES), have been examined in clinical trials. Nevertheless, their success has been scarce mainly due to their low bioavailability. In this study, we found serendipitously that O-silyl RES derivatives exerted a better neuroprotective activity than resveratrol itself and decided to explore them as potential drugs for neurodegenerative and neurological diseases. We have also designed and prepared a series of O-silyl RES prodrugs to improve their bioavailability. We found that di-triethylsilyl and di-triisopropylsilyl RES derivatives were better in vitro neuroprotective and anti-inflammatory agents than RES. Among these derivatives and their corresponding acyl-, glycosyl- and carbamoyl-prodrugs, 3,5-triethylsilyl-4'-(6â³-octanoylglucopyranosyl) resveratrol 26 showed the best profile on toxicity and neuroprotective activity in zebra fish embryo. Compound 26 was also capable of reducing the loss of motor coordination in a 3-nitropropionic acid mice model of Huntington's disease, in a similar way to RES. However, 26 diminished pro-inflammatory cytokine IL-6 to a higher extent than RES and improved the latency to fall in the rotarod test by 10% with respect to RES. Finally, we investigated 26 and RES as potential treatments on an experimental autoimmune encephalomyelitis (EAE) multiple sclerosis mice model. We observed that, in a therapeutic regimen, 26 significantly diminished the progression of EAE severity and reduced the percentage of animals with moderate to severe clinical score, whereas RES showed no improvement.
Assuntos
Encefalomielite Autoimune Experimental/tratamento farmacológico , Esclerose Múltipla/tratamento farmacológico , Fármacos Neuroprotetores/uso terapêutico , Pró-Fármacos/química , Resveratrol/química , Compostos de Silício/química , Animais , Anti-Inflamatórios/química , Anti-Inflamatórios/farmacologia , Anti-Inflamatórios/uso terapêutico , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Modelos Animais de Doenças , Embrião não Mamífero/efeitos dos fármacos , Encefalomielite Autoimune Experimental/patologia , Humanos , Macrófagos/citologia , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Esclerose Múltipla/patologia , Fármacos Neuroprotetores/química , Fármacos Neuroprotetores/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Pró-Fármacos/farmacologia , Pró-Fármacos/uso terapêutico , Fator de Necrose Tumoral alfa/metabolismo , Peixe-Zebra/crescimento & desenvolvimentoRESUMO
Cellulose acetate (CA) ultrafiltration membranes were successfully prepared using the non-solvent induced phase separation (NIPS) methodology. This technique is used to produce porous membranes for a large variety of applications. However, the formation of a dense skin during the process reduces membrane pure water flux (PWF). To overcome this issue, three parameters were investigated: CA/NMP (N-methyl-2-pyrrolidone) ratio in the casting solution, acetone (Ac)/water (W) ratio in the precipitation bath composition (PBC) and support material (glass/polyethylene). The effect of each factor on the mean pore size, water contact angle, porosity and PWF was supported by Taguchi design. The increase in the CA/NMP ratio reduced mean pore size and porosity. In contrast, there was an increase in porosity and hydrophilicity with increasing Ac/W ratio. The maximum value of PWF was obtained for membranes prepared using a PE support. ANOVA showed that most, but not all, factors had significant effects on the parameters measured.
Assuntos
Celulose/análogos & derivados , Membranas Artificiais , Pirrolidinonas/química , Água/química , Acetona/química , Análise de Variância , Celulose/química , Precipitação Química , Vidro , Interações Hidrofóbicas e Hidrofílicas , Polietileno , Porosidade , Soluções/química , Temperatura , Ultrafiltração/métodosRESUMO
Here we present a novel G4-binding family of compounds based on a central core of phenyl ditriazole (PDTZ) modified with carbohydrates and phenyl pyrrolidinyl side-chains. Their synthesis was achieved using controlled click chemistry conditions to obtain both, symmetric and dissymmetric carb-PDTZ derivatives without any intermediate protecting steps through an optimized methodology. Binding of the new carb-PDTZ to a variety of G-quadruplex motifs was examined using different biophysical techniques. The symmetric carb-PDTZ derivatives were not able to stabilize G4, but the dissymmetric ones (containing one sugar and one phenyl pyrrolidinyl side-chain) did. Interestingly, the dissymmetric carb-PDTZ derivatives showed much higher G4 vs duplex DNA selectivity than the control compound PDTZ 1, which contains two phenyl pyrrodilinyl side-chains and no carbohydrates. Their potential antitumoral activity was also investigated by in vitro cytotoxicity measurements on different cancerous cell lines. All carb-PDTZ derivatives showed higher IC50 values than the control PDTZ 1, probably due to the lack of compound stability of some derivatives and to lower cellular uptake.
Assuntos
Antineoplásicos/farmacologia , Quadruplex G/efeitos dos fármacos , Triazóis/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Ligantes , Estrutura Molecular , Relação Estrutura-Atividade , Triazóis/síntese química , Triazóis/químicaRESUMO
We present G4-iM Grinder, a system for the localization, characterization and selection of potential G4s, i-Motifs and higher order structures. A robust and highly adaptable search engine identifies all structures that fit the user's quadruplex definitions. Their biological relevance, in vitro formation probability and presence of known-to-form structures are then used as filters. The outcome is an efficient methodology that helps select the best candidates for a subsequent in vitro analysis or a macroscopic genomic quadruplex assessment. As proof of the analytical capabilities of G4-iM Grinder, the human genome was analyzed for potential G4s and i-Motifs. Many known-to-form structures were identified. New candidates were selected considering their score and appearance frequency. We also focused on locating Potential Higher Order Quadruplex Sequences (PHOQS). We developed a new methodology to predict the most probable subunits of these assemblies and applied it to a PHOQS candidate. Taking the human average density as reference, we examined the genomes of several etiological causes of disease. This first of its class comparative study found many organisms to be very dense in these potential quadruplexes. Many presented already known-to-form-G4s and i-Motifs. These findings suggest the potential quadruplexes have as therapeutic targets for these diseases that currently kill millions worldwide.
RESUMO
There is currently no satisfactory treatment for visceral leishmaniasis; the disease is thus in desperate need of novel drugs. The ideal candidate should be effective, safe, affordable, and administered via the oral route. Histone deacetylases (HDACs) are involved in silencing critical regulatory pathways, including pro-apoptotic programs, and represent potential therapeutic targets for pharmacological interventions. O-alkyl hydroxamates have traditionally been considered to exert no effect on mammal HDACs. The aim of this study was to evaluate the effect of MDG, a SAHA derivative of the O-alkyl hydroxamate family with no activity on human histone deacetylase enzymes, on the visceral leishmaniasis causative agents and in a murine model of the disease. The effects of vorinostat, tubacin and valproic acid (well-known mammal HDAC inhibitors) on the parasite were also evaluated. MDG was found to be highly active against Leishmania infantum and L. donovani intracellular amastigotes in vitro but not against the promastigote stage. In contrast, vorinostat, tubacin and valproic acid showed no activity against the parasite. Assays investigating hERG and Cav1.2 channels in vitro found no evidence of MDG-driven cardiotoxicity. MDG showed neither hepatotoxicity nor mutagenicity, nor did it exert activity on cytochrome P450 enzymes. MDG was adsorbed onto gold nanoparticles for the in vivo experiments, performed on infected Balb/c mice. MDG was effective at reducing the parasite load in major target tissues (bone marrow, spleen and liver) in more than 70% at 25 mg/kg through both the oral and intraperitoneal route, proving more active than the reference compounds (meglumine antimoniate, MA) without showing toxicity. In addition, the combination of MDG and MA was very effective.
Assuntos
Antiprotozoários/administração & dosagem , Ouro/administração & dosagem , Leishmaniose Visceral/tratamento farmacológico , Nanopartículas/administração & dosagem , Vorinostat/análogos & derivados , Vorinostat/administração & dosagem , Administração Oral , Anilidas/administração & dosagem , Animais , Sistemas de Liberação de Medicamentos , Feminino , Inibidores de Histona Desacetilases/administração & dosagem , Ácidos Hidroxâmicos/administração & dosagem , Leishmania infantum/efeitos dos fármacos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos ICR , Ácido Valproico/administração & dosagemRESUMO
The synthesis of a novel α-glucosylated derivative of pterostilbene was performed by a transglycosylation reaction using starch as glucosyl donor, catalyzed by cyclodextrin glucanotransferase (CGTase) from Thermoanaerobacter sp. The reaction was carried out in a buffer containing 20% (v/v) DMSO to enhance the solubility of pterostilbene. Due to the formation of several polyglucosylated products with CGTase, the yield of monoglucoside was increased by the treatment with a recombinant amyloglucosidase (STA1) from Saccharomyces cerevisiae (var. diastaticus). This enzyme was not able to hydrolyze the linkage between the glucose and pterostilbene. The monoglucoside was isolated and characterized by combining ESI-MS and 2D-NMR methods. Pterostilbene α-d-glucopyranoside is a novel compound. The α-glucosylation of pterostilbene enhanced its solubility in water to approximately 0.1 g/L. The α-glucosylation caused a slight loss of antioxidant activity towards ABTSË⺠radicals. Pterostilbene α-d-glucopyranoside was less toxic than pterostilbene for human SH-S5Y5 neurons, MRC5 fibroblasts and HT-29 colon cancer cells, and similar for RAW 264.7 macrophages.
Assuntos
Antineoplásicos/síntese química , Antioxidantes/síntese química , Proteínas de Bactérias/química , Glucana 1,4-alfa-Glucosidase/química , Glucosídeos/síntese química , Glucosiltransferases/química , Estilbenos/química , Animais , Antineoplásicos/farmacologia , Antioxidantes/farmacologia , Proteínas de Bactérias/isolamento & purificação , Biocatálise , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Fibroblastos/patologia , Glucana 1,4-alfa-Glucosidase/biossíntese , Glucosídeos/farmacologia , Glucosiltransferases/biossíntese , Glicosilação , Células HT29 , Humanos , Concentração Inibidora 50 , Camundongos , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Neurônios/patologia , Células RAW 264.7 , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/química , Saccharomyces cerevisiae/química , Saccharomyces cerevisiae/enzimologia , Solubilidade , Amido/química , Thermoanaerobacter/química , Thermoanaerobacter/enzimologiaRESUMO
Resveratrol is a naturally occurring stilbene which has shown promising results as treatment for several neurodegenerative diseases. However, its application is limited due to its low efficacy and bioavailability. Here, we have designed and synthesized alkylated resveratrol prodrugs combining structural modification to improve antioxidant and anti-inflammatory properties and the preparation of prodrugs to extend drug bioavailability. For comparison we also studied resveratrol prodrugs and alkylated resveratrol derivatives. Methylated and butylated resveratrol derivatives showed the best in vitro neuroprotective and anti-inflammatory activity. The glucosyl- and glucosyl-acyl- prodrugs of these derivatives showed lower toxicity on zebra fish embryo. When neuroprotection was examined on pentylenetetrazole challenged zebra fish, they were capable of reverting neuronal damage but to a lower extent than resveratrol. Nevertheless, 3-O-(6'-O-octanoyl)-ß-d-glucopyranoside resveratrol (compound 8) recovered AChE activity over 100% whereas resveratrol only up to 92%. In a 3-nitropropionic acid mice model of Huntington's disease, resveratrol derivative 8 delayed the onset and reduced the severity of HD-like symptoms, by improving locomotor activity and protecting against weight loss. Its effects involved an equal antioxidant but better anti-inflammatory profile than resveratrol as shown by SOD2 expression in brain tissue and circulating levels of IL-6 (11 vs 18â¯pg/mL), respectively. Finally, the octanoyl chain in compound 8 could be playing a role in inflammation and neuronal development indicating it could be acting as a double-drug, instead of as a prodrug.
Assuntos
Doenças Neurodegenerativas/tratamento farmacológico , Pró-Fármacos/uso terapêutico , Alquilação , Animais , Sobrevivência Celular/efeitos dos fármacos , Citocinas/biossíntese , Relação Dose-Resposta a Droga , Humanos , Inflamação/induzido quimicamente , Inflamação/tratamento farmacológico , Camundongos , Camundongos Endogâmicos C57BL , Estrutura Molecular , Doenças Neurodegenerativas/induzido quimicamente , Neurônios/efeitos dos fármacos , Neurônios/patologia , Nitrocompostos , Pró-Fármacos/química , Pró-Fármacos/metabolismo , Propionatos , Células RAW 264.7 , Relação Estrutura-Atividade , Células Tumorais Cultivadas , Peixe-ZebraRESUMO
G-quadruplexes (G4) are DNA secondary structures that take part in the regulation of gene expression. Putative G4 forming sequences (PQS) have been reported in mammals, yeast, bacteria, and viruses. Here, we present PQS searches on the genomes of T. brucei, L. major, and P. falciparum. We found telomeric sequences and new PQS motifs. Biophysical experiments showed that EBR1, a 29 nucleotide long highly repeated PQS in T. brucei, forms a stable G4 structure. G4 ligands based on carbohydrate conjugated naphthalene diimides (carb-NDIs) that bind G4's including hTel could bind EBR1 with selectivity versus dsDNA. These ligands showed important antiparasitic activity. IC50 values were in the nanomolar range against T. brucei with high selectivity against MRC-5 human cells. Confocal microscopy confirmed these ligands localize in the nucleus and kinetoplast of T. brucei suggesting they can reach their potential G4 targets. Cytotoxicity and zebrafish toxicity studies revealed sugar conjugation reduces intrinsic toxicity of NDIs.
Assuntos
Antiparasitários/química , Antiparasitários/farmacologia , Quadruplex G/efeitos dos fármacos , Genoma de Protozoário/genética , Imidas/química , Imidas/farmacologia , Naftalenos/química , Naftalenos/farmacologia , Animais , Antiparasitários/toxicidade , Linhagem Celular , Humanos , Imidas/toxicidade , Ligantes , Naftalenos/toxicidade , Telômero/genética , Peixe-ZebraRESUMO
The eco-friendly synthesis of non-natural glycosides from different phenolic antioxidants was carried out using a fungal ß-xylosidase to evaluate changes in their bioactivities. Xylosides from hydroquinone and catechol were successfully formed, although the best results were obtained for hydroxytyrosol, the main antioxidant from olive oil. The formation of the new products was followed by thin-layer chromatography, liquid chromatography, and mass spectrometry. The hydroxytyrosyl xyloside was analyzed in more detail, to maximize its production and evaluate the effect of glycosylation on some hydroxytyrosol properties. The synthesis was optimized up to the highest production reported for a hydroxytyrosyl glycoside. The structure of this compound was solved by two-dimensional nuclear magnetic resonance and identified as 3,4-dihydroxyphenyl-ethyl-O-ß-d-xylopyranoside. Evaluation of its biological effect showed an enhancement of both its neuroprotective capacity and its ability to ameliorate intracellular levels of reactive oxygen species.
Assuntos
Proteínas Fúngicas/química , Glicosídeos/química , Fármacos Neuroprotetores/química , Azeite de Oliva/química , Álcool Feniletílico/análogos & derivados , Talaromyces/enzimologia , Xilosidases/química , Biocatálise , Cromatografia em Camada Fina , Espectroscopia de Ressonância Magnética , Fenóis/química , Álcool Feniletílico/químicaRESUMO
The G-quadruplexes (G4s) are currently being explored as therapeutic targets in cancer and other pathologies. Six carbohydrate naphthalene diimide conjugates (carb-NDIs) have been synthesized as G4 ligands to investigate their potential selectivity in G4 binding and cell penetration. Carb-NDIs have shown certain selectivity for G4 structures against DNA duplexes, but different sugar moieties do not induce a preference for a specific G4 topology. Interestingly, when monosaccharides were attached through a short ethylene linker to the NDI scaffold, their cellular uptake was two- to threefold more efficient than that when the sugar was directly attached through its anomeric position. Moreover, a correlation between more efficient cell uptake of these carb-NDIs and their higher toxicity in cancerous cell lines has been observed. Carb-NDIs seem to be mainly translocated into cancer cells through glucose transporters (GLUT), of which GLUT4 plays a major role.
RESUMO
Trypanosomiasis and leishmaniasis keep being a real challenge for health and development of African countries. Existing treatments have considerable side effects and increase resistance of the parasites. We have measured antitrypanosomal and antileishmanial activity of natural phenols, tyrosol (TYR) and hydroxytyrosol (HT) and several of their esters and metabolites. We found significant IC50 values against Trypanosoma brucei for HT decanoate ester and HT dodecanoate ester (0.6 and 0.36 µM, respectively). This represents a large increase in activity with respect to HT (79 and 132 fold, respectively). Moreover, both compounds displayed a high selectivity index against MRC-5, a non-tumoral human cell line (118 and 106, respectively). Then, we synthesized a focused library of compounds to explore structure-activity. We found the ether and thiourea analogs of HT decanoate ester and HT dodecanoate ester also showed IC50 values against T. brucei in the low micromolar range. In conclusion, the di-ortho phenolic ring and medium size alkyl chain are essential for activity whereas the nature of the chemical bond among them seems less important.