Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 41
Filtrar
Más filtros

Tipo del documento
Intervalo de año de publicación
2.
J Biol Chem ; 296: 100180, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33303629

RESUMEN

Glycoconjugates play a central role in several cellular processes, and alteration in their composition is associated with numerous human pathologies. Substrates for cellular glycosylation are synthesized in the hexosamine biosynthetic pathway, which is controlled by the glutamine:fructose-6-phosphate amidotransfera-se (GFAT). Human isoform 2 GFAT (hGFAT2) has been implicated in diabetes and cancer; however, there is no information about structural and enzymatic properties of this enzyme. Here, we report a successful expression and purification of a catalytically active recombinant hGFAT2 (rhGFAT2) in Escherichia coli cells fused or not to a HisTag at the C-terminal end. Our enzyme kinetics data suggest that hGFAT2 does not follow the expected ordered bi-bi mechanism, and performs the glucosamine-6-phosphate synthesis much more slowly than previously reported for other GFATs. In addition, hGFAT2 is able to isomerize fructose-6-phosphate into glucose-6-phosphate even in the presence of equimolar amounts of glutamine, which results in unproductive glutamine hydrolysis. Structural analysis of a three-dimensional model of rhGFAT2, corroborated by circular dichroism data, indicated the presence of a partially structured loop in the glutaminase domain, whose sequence is present in eukaryotic enzymes but absent in the E. coli homolog. Molecular dynamics simulations suggest that this loop is the most flexible portion of the protein and plays a key role on conformational states of hGFAT2. Thus, our study provides the first comprehensive set of data on the structure, kinetics, and mechanics of hGFAT2, which will certainly contribute to further studies on the (patho)physiology of hGFAT2.


Asunto(s)
Glutamina-Fructosa-6-Fosfato Transaminasa (Isomerizadora)/metabolismo , Glutamina-Fructosa-6-Fosfato Transaminasa (Isomerizadora)/química , Humanos , Cinética , Simulación de Dinámica Molecular , Conformación Proteica , Dominios Proteicos , Multimerización de Proteína
3.
Glycoconj J ; 39(5): 653-661, 2022 10.
Artículo en Inglés | MEDLINE | ID: mdl-35536494

RESUMEN

At cell surface gangliosides might associate with signal transducers proteins, grown factor receptors, integrins, small G-proteins and tetraspanins establishing microdomains, which play important role in cell adhesion, cell activation, motility, and growth. Previously, we reported that GM2 and GM3 form a heterodimer that interacts with the tetraspanin CD82, controlling epithelial cell mobility by inhibiting integrin-hepatocyte growth factor-induced cMet tyrosine kinase signaling. By using molecular dynamics simulations to study the molecular basis of GM2/GM3 interaction we demonstrate, here, that intracellular levels of Ca2+ mediate GM2/GM3 complexation via electrostatic interaction with their carboxyl groups, while hydrogen bonds between the ceramide groups likely aid stabilizing the complex. The presence of GM2/GM3 complex alters localization of CD82 on cell surface and therefore downstream signalization. These data contribute for the knowledge of how glycosylation may control signal transduction and phenotypic changes.


Asunto(s)
Gangliósido G(M3) , Proteína Kangai-1 , Adhesión Celular , Movimiento Celular , Proteína Kangai-1/metabolismo , Transducción de Señal
4.
Dev Dyn ; 247(3): 481-491, 2018 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-28722313

RESUMEN

Epithelial to mesenchymal transition (EMT) is a developmental program reactivated by tumor cells that leads to the switch from epithelial to mesenchymal phenotype. During EMT, cells are transcriptionally regulated to decrease E-cadherin expression while expressing mesenchymal markers such as vimentin, fibronectin, and N-cadherin. Growing body of evidences suggest that cells engaged in EMT undergo a metabolic reprograming process, redirecting glucose flux toward hexosamine biosynthesis pathway (HBP), which fuels aberrant glycosylation patterns that are extensively observed in cancer cells. HBP depends on nutrient availability to produce its end product UDP-GlcNAc, and for this reason is considered a metabolic sensor pathway. UDP-GlcNAc is the substrate used for the synthesis of major types of glycosylation, including O-GlcNAc and cell surface glycans. In general, the rate limiting enzyme of HBP, GFAT, is overexpressed in many cancer types that present EMT features as well as aberrant glycosylation. Moreover, altered levels of O-GlcNAcylation can modulate cell morphology and favor EMT. In this review, we summarize some of the current knowledge that correlates glucose metabolism, aberrant glycosylation and hyper O-GlcNAcylation supported by HBP that leads to EMT activation. Developmental Dynamics 247:481-491, 2018. © 2017 Wiley Periodicals, Inc.


Asunto(s)
Plasticidad de la Célula , Transición Epitelial-Mesenquimal , Redes y Vías Metabólicas , Animales , Glicosilación , Hexosaminas/biosíntesis , Humanos
5.
J Bioenerg Biomembr ; 50(3): 175-187, 2018 06.
Artículo en Inglés | MEDLINE | ID: mdl-29322286

RESUMEN

A number of cancer types have shown an increased prevalence and a higher mortality rate in patients with hyperglycemic associated pathologies. Although the correlation between diabetes and cancer incidence has been increasingly reported, the underlying molecular mechanisms beyond this association are not yet fully understood. Recent studies have suggested that high glucose levels support tumor progression through multiple mechanisms that are hallmarks of cancer, including cell proliferation, resistance to apoptosis, increased cell migration and invasiveness, epigenetic regulation (hyperglycemic memory), resistance to chemotherapy and altered metabolism. Most of the above occur because hyperglycemia through hexosamine biosynthetic pathway leads to aberrant O-GlcNAcylation of many intracellular proteins that are involved in those mechanisms. Deregulated O-GlcNAcylation is emerging as a general feature of cancer. Despite strong evidence suggesting that aberrant O-GlcNAcylation is or may be involved in the acquisition of all cancer hallmarks, it remains out of the list of the next generation of emerging hallmarks. Here, we discuss some of the current understanding on how hyperglycemia affects cancer cell biology and how aberrant O-GlcNAcylation stands in this context.


Asunto(s)
Acetilglucosamina/metabolismo , Hiperglucemia/complicaciones , Neoplasias/metabolismo , Animales , Progresión de la Enfermedad , Glicosilación , Humanos
6.
J Biol Chem ; 291(25): 12917-29, 2016 Jun 17.
Artículo en Inglés | MEDLINE | ID: mdl-27129262

RESUMEN

Deregulated cellular metabolism is a hallmark of tumors. Cancer cells increase glucose and glutamine flux to provide energy needs and macromolecular synthesis demands. Several studies have been focused on the importance of glycolysis and pentose phosphate pathway. However, a neglected but very important branch of glucose metabolism is the hexosamine biosynthesis pathway (HBP). The HBP is a branch of the glucose metabolic pathway that consumes ∼2-5% of the total glucose, generating UDP-GlcNAc as the end product. UDP-GlcNAc is the donor substrate used in multiple glycosylation reactions. Thus, HBP links the altered metabolism with aberrant glycosylation providing a mechanism for cancer cells to sense and respond to microenvironment changes. Here, we investigate the changes of glucose metabolism during epithelial mesenchymal transition (EMT) and the role of O-GlcNAcylation in this process. We show that A549 cells increase glucose uptake during EMT, but instead of increasing the glycolysis and pentose phosphate pathway, the glucose is shunted through the HBP. The activation of HBP induces an aberrant cell surface glycosylation and O-GlcNAcylation. The cell surface glycans display an increase of sialylation α2-6, poly-LacNAc, and fucosylation, all known epitopes found in different tumor models. In addition, modulation of O-GlcNAc levels was demonstrated to be important during the EMT process. Taken together, our results indicate that EMT is an applicable model to study metabolic and glycophenotype changes during carcinogenesis, suggesting that cell glycosylation senses metabolic changes and modulates cell plasticity.


Asunto(s)
Transición Epitelial-Mesenquimal , Procesamiento Proteico-Postraduccional , Adenosina Trifosfato/metabolismo , Vías Biosintéticas , Línea Celular Tumoral , Inducción Enzimática , Glucosa/metabolismo , Glucógeno/metabolismo , Glicosilación , Hexosaminas/biosíntesis , Humanos , Ácido Láctico/metabolismo , N-Acetilglucosaminiltransferasas/genética , N-Acetilglucosaminiltransferasas/metabolismo , Ácido Pirúvico/metabolismo , Factor de Crecimiento Transformador beta/fisiología
7.
J Biol Chem ; 289(1): 423-36, 2014 Jan 03.
Artículo en Inglés | MEDLINE | ID: mdl-24194520

RESUMEN

Trypanosoma cruzi trans-sialidase (TcTS) is a key target protein for Chagas disease chemotherapy. In this study, we investigated the implications of active site flexibility on the biochemical mechanism of TcTS. Molecular dynamics studies revealed remarkable plasticity in the TcTS catalytic site, demonstrating, for the first time, how donor substrate engagement with the enzyme induces an acceptor binding site in the catalytic pocket that was not previously captured in crystal structures. Furthermore, NMR data showed cooperative binding between donor and acceptor substrates, supporting theoretical results. In summary, our data put forward a coherent dynamic framework to understand how a glycosidase evolved its highly efficient trans-glycosidase activity.


Asunto(s)
Evolución Molecular , Simulación de Dinámica Molecular , Proteínas Protozoarias/química , Trypanosoma cruzi/enzimología , Catálisis , Dominio Catalítico , Glicoproteínas , Neuraminidasa , Resonancia Magnética Nuclear Biomolecular , Proteínas Protozoarias/genética , Proteínas Protozoarias/metabolismo , Trypanosoma cruzi/genética
8.
Arch Insect Biochem Physiol ; 90(2): 104-15, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-26111116

RESUMEN

Lipid peroxidation is promoted by the quasi-lipoxygenase (QL) activity of heme proteins and enhanced by the presence of free calcium. Unlike mammalian plasma, the hemolymph of Rhodnius prolixus, a vector of Chagas disease, contains both a free heme-binding protein (RHBP) and circulating lipoproteins. RHBP binds and prevents the heme groups of the proteins from participating in lipid peroxidation reactions. Herein, we show that despite being bound to RHBP, heme groups promote lipid peroxidation through a calcium-dependent QL reaction. This reaction is readily inhibited by the presence of ethylene glycol tetraacetic acid (EGTA), the antioxidant butylated hydroxytoluene or micromolar levels of the main yolk phosphoprotein vitellin (Vt). The inhibition of lipid peroxidation is eliminated by the in vitro dephosphorylation of Vt, indicating that this reaction depends on the interaction of free calcium ions with negatively charged phosphoamino acids. Our results demonstrate that calcium chelation mediated by phosphoproteins occurs via an antioxidant mechanism that protects living organisms from lipid peroxidation.


Asunto(s)
Calcio/metabolismo , Proteínas Portadoras/metabolismo , Hemoproteínas/metabolismo , Peroxidación de Lípido , Rhodnius/metabolismo , Vitelinas/metabolismo , Animales , Femenino , Proteínas de Unión al Hemo , Hemolinfa/metabolismo , Proteínas de Insectos/metabolismo , Conejos
9.
Subcell Biochem ; 74: 181-201, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24264246

RESUMEN

Trypanosoma cruzi trans-sialidase (TcTS) has intrigued researchers all over the world since it was shown that T. cruzi incorporates sialic acid through a mechanism independent of sialyltransferases. The enzyme has being involved in a vast myriad of functions in the biology of the parasite and in the pathology of Chagas' disease. At the structural level experiments trapping the intermediate with fluorosugars followed by peptide mapping, X-ray crystallography, molecular modeling and magnetic nuclear resonance have opened up a three-dimensional understanding of the way this enzyme works. Herein we review the multiple biological roles of TcTS and the structural studies that are slowly revealing the secrets underlining an efficient sugar transfer activity rather than simple hydrolysis by TcTS.


Asunto(s)
Glicoproteínas/química , Neuraminidasa/química , Trypanosoma cruzi/enzimología , Animales , Biocatálisis , Cristalografía por Rayos X , Glicoproteínas/metabolismo , Modelos Moleculares , Neuraminidasa/metabolismo , Conformación Proteica , Especificidad por Sustrato
10.
Glycobiology ; 24(5): 458-68, 2014 May.
Artículo en Inglés | MEDLINE | ID: mdl-24578376

RESUMEN

Induced pluripotent stem (iPS) cells are somatic cells that have been reprogrammed to a pluripotent state via the introduction of defined transcription factors. Although iPS is a potentially valuable resource for regenerative medicine and drug development, several issues regarding their pluripotency, differentiation propensity and potential for tumorigenesis remain to be elucidated. Analysis of cell surface glycans has arisen as an interesting tool for the characterization of iPS. An appropriate characterization of glycan surface molecules of human embryonic stem (hES) cells and iPS cells might generate crucial data to highlight their role in the acquisition and maintenance of pluripotency. In this study, we characterized the surface glycans of iPS generated from menstrual blood-derived mesenchymal cells (iPS-MBMC). We demonstrated that, upon spontaneous differentiation, iPS-MBMC present high amounts of terminal ß-galactopyranoside residues, pointing to an important role of terminal-linked sialic acids in pluripotency maintenance. The removal of sialic acids by neuraminidase induces iPS-MBMC and hES cells differentiation, prompting an ectoderm commitment. Exposed ß-galactopyranose residues might be recognized by carbohydrate-binding molecules found on the cell surface, which could modulate intercellular or intracellular interactions. Together, our results point for the first time to the involvement of the presence of terminal sialic acid in the maintenance of embryonic stem cell pluripotency and, therefore, the modulation of sialic acid biosynthesis emerges as a mechanism that may govern stem cell differentiation.


Asunto(s)
Diferenciación Celular/fisiología , Células Madre Embrionarias/metabolismo , Células Madre Pluripotentes Inducidas/metabolismo , Glicoproteínas de Membrana/metabolismo , Línea Celular , Células Madre Embrionarias/citología , Humanos , Células Madre Pluripotentes Inducidas/citología , Ácido N-Acetilneuramínico/metabolismo
11.
Glycobiology ; 23(4): 438-52, 2013 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-23263200

RESUMEN

The glycobiology of the cestodes, a class of parasitic flatworms, is still largely unexplored. An important cestode species is Echinococcus granulosus, the tissue-dwelling larval stage of which causes hydatid disease. The E. granulosus larva is protected from the host by a massive mucin-based extracellular matrix termed laminated layer (LL). We previously reported ( Díaz et al. 2009. Biochemistry 48:11678-11691) the molecular structure of the most abundant LL O-glycans, comprising up to six monosaccharide residues. These are based on Cores 1 and 2, in cases elongated by a chain of Galpß1-3 residues, which can be capped by Galpα1-4. In addition, the Core 2 GlcNAcp residue can be decorated with the Galpα1-4Galpß1-4 disaccharide. Larger glycans also detected contained additional HexNAc residues that could not be explained by the structural repertoire described above. In this work, we elucidate, by mass spectrometry (MS) and nuclear magnetic resonance (NMR), six additional glycans from the E. granulosus LL between six and eight residues in size. Their structures are related to those already described but in cases bear GlcNAcpß1-6 or Galpα1-4Galpß1-4GlcNAcpß1-6 as ramifications on the core Galpß1-3 residue. We also obtained evidence that noncore Galpß1-3 residues can be similarly ramified. Thus, the new motif together with the previous information may explain all the glycan compositions detected in the LL by MS. In addition, we show that the anti-Echinococcus monoclonal antibody E492 (Parasite Immunol 21:141, 1999) recognizes Galpα1-4Galpß1-4GlcNAcp (the blood P(1)-antigen motif). This explains the antibody's reactivity with a range of Echinococcus tissues, as the P(1)-motif is also carried on non-LL N-glycans and glycolipids from this genus.


Asunto(s)
Echinococcus granulosus/química , Polisacáridos/química , Animales , Conformación de Carbohidratos , Globósidos/inmunología , Monosacáridos/química , Polisacáridos/inmunología
12.
Cancers (Basel) ; 15(19)2023 Sep 27.
Artículo en Inglés | MEDLINE | ID: mdl-37835434

RESUMEN

Glioblastoma (GB) is the most aggressive primary malignant brain tumor and is associated with short survival. O-GlcNAcylation is an intracellular glycosylation that regulates protein function, enzymatic activity, protein stability, and subcellular localization. Aberrant O-GlcNAcylation is related to the tumorigenesis of different tumors, and mounting evidence supports O-GlcNAc transferase (OGT) as a potential therapeutic target. Here, we used two human GB cell lines alongside primary human astrocytes as a non-tumoral control to investigate the role of O-GlcNAcylation in cell proliferation, cell cycle, autophagy, and cell death. We observed that hyper O-GlcNAcylation promoted increased cellular proliferation, independent of alterations in the cell cycle, through the activation of autophagy. On the other hand, hypo O-GlcNAcylation inhibited autophagy, promoted cell death by apoptosis, and reduced cell proliferation. In addition, the decrease in O-GlcNAcylation sensitized GB cells to the chemotherapeutic temozolomide (TMZ) without affecting human astrocytes. Combined, these results indicated a role for O-GlcNAcylation in governing cell proliferation, autophagy, cell death, and TMZ response, thereby indicating possible therapeutic implications for treating GB. These findings pave the way for further research and the development of novel treatment approaches which may contribute to improved outcomes and increased survival rates for patients facing this challenging disease.

13.
J Biol Chem ; 285(18): 13388-96, 2010 Apr 30.
Artículo en Inglés | MEDLINE | ID: mdl-20106975

RESUMEN

Upon activation, cytotoxic CD8(+) T lymphocytes are desialylated exposing beta-galactose residues in a physiological change that enhances their effector activity and that can be monitored on the basis of increased binding of the lectin peanut agglutinin. Herein, we investigated the impact of sialylation mediated by trans-sialidase, a specific and unique Trypanosoma transglycosylase for sialic acid, on CD8(+) T cell response of mice infected with T. cruzi. Our data demonstrate that T. cruzi uses its trans-sialidase enzyme to resialylate the CD8(+) T cell surface, thereby dampening antigen-specific CD8(+) T cell response that might favor its own persistence in the mammalian host. Binding of the monoclonal antibody S7, which recognizes sialic acid-containing epitopes on the 115-kDa isoform of CD43, was augmented on CD8(+) T cells from ST3Gal-I-deficient infected mice, indicating that CD43 is one sialic acid acceptor for trans-sialidase activity on the CD8(+) T cell surface. The cytotoxic activity of antigen-experienced CD8(+) T cells against the immunodominant trans-sialidase synthetic peptide IYNVGQVSI was decreased following active trans-sialidase-mediated resialylation in vitro and in vivo. Inhibition of the parasite's native trans-sialidase activity during infection strongly decreased CD8(+) T cell sialylation, reverting it to the glycosylation status expected in the absence of parasite manipulation increasing mouse survival. Taken together, these results demonstrate, for the first time, that T. cruzi subverts sialylation to attenuate CD8(+) T cell interactions with peptide-major histocompatibility complex class I complexes. CD8(+) T cell resialylation may represent a sophisticated strategy to ensure lifetime host parasitism.


Asunto(s)
Antígenos de Protozoos/metabolismo , Linfocitos T CD8-positivos/metabolismo , Ácido N-Acetilneuramínico/metabolismo , Neuraminidasa/metabolismo , Péptidos/metabolismo , Proteínas Protozoarias/metabolismo , Trypanosoma cruzi/enzimología , Animales , Anticuerpos Monoclonales/inmunología , Antígenos de Protozoos/genética , Antígenos de Protozoos/inmunología , Linfocitos T CD8-positivos/inmunología , Enfermedad de Chagas/enzimología , Enfermedad de Chagas/genética , Enfermedad de Chagas/inmunología , Epítopos/genética , Epítopos/inmunología , Epítopos/metabolismo , Glicosilación , Antígenos de Histocompatibilidad Clase I/genética , Antígenos de Histocompatibilidad Clase I/inmunología , Antígenos de Histocompatibilidad Clase I/metabolismo , Leucosialina/genética , Leucosialina/inmunología , Leucosialina/metabolismo , Activación de Linfocitos/genética , Activación de Linfocitos/inmunología , Masculino , Ratones , Ratones Endogámicos BALB C , Ácido N-Acetilneuramínico/genética , Ácido N-Acetilneuramínico/inmunología , Neuraminidasa/inmunología , Péptidos/genética , Péptidos/inmunología , Proteínas Protozoarias/genética , Proteínas Protozoarias/inmunología , Sialiltransferasas/genética , Sialiltransferasas/inmunología , Sialiltransferasas/metabolismo , Trypanosoma cruzi/genética , Trypanosoma cruzi/inmunología , beta-Galactosida alfa-2,3-Sialiltransferasa
14.
Glycobiology ; 20(3): 338-47, 2010 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-19933228

RESUMEN

Burkholderia kururiensis, strain M130, an endophytic diazotrophic bacterium isolated from rice roots, produces acetylated acidic exopolysaccharides which can be separated by anion exchange chromatography. These were characterized by nuclear magnetic resonance spectroscopy, methylation analysis and Smith degradation. The exopolysaccharides eluted with 0.5 M NaCl were produced when the bacterium was grown in a medium containing mannitol as the sole carbon source, and showed to be a mixture of two different polymers, composed of hepta or octasaccharide repeat units, consistent with following structure: [structure: see text]. The ability of diazotrophic Burkholderia to produce two exopolysaccharides that differ by the presence of a terminal glucosyl residue provides insight into polysaccharide function with potentially significant biological consequences in the endophytic-host plant interaction.


Asunto(s)
Burkholderia/metabolismo , Fijación del Nitrógeno , Polisacáridos Bacterianos/química , Secuencia de Carbohidratos , Datos de Secuencia Molecular , Nitrógeno/metabolismo , Polisacáridos Bacterianos/aislamiento & purificación
15.
Glycobiology ; 20(8): 1034-45, 2010 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-20466651

RESUMEN

One of the most interesting aspects of Trypanosoma cruzi is its adaptation to obtain sialic acid from its host, fulfilling this need exclusively through the reaction catalyzed by enzymatically active trans-sialidase (aTS), thought to play an important role in the pathogenesis of Chagas' disease. Herein, we report that 2-difluoromethyl-4-nitrophenyl-3,5-dideoxy-d-glycero-alpha-d-galacto-2-nonulopyranosid acid (NeuNAcFNP) inactivates aTS time- and dose-dependently, and this inhibition was not relieved removing the inhibitor. Also, NeuNAcFNP causes a decrease in infection of mammalian cells. Characterization of labeled aTS by matrix-assisted laser desorption/ionization time-of-flight/time-of-flight mass spectrometry revealed that inactivation of the enzyme occurs through formation of a covalent bond between Arg245 and Asp247 and the inhibitor aglycone. Participation of Asp247 in the catalytic mechanism was proved by constructing a TSD247A mutant, which presents only residual activity. Molecular dynamic simulations indicate that the D247A mutation results in a more open catalytic cleft. In summary, NeuNAcFNP is the first reported mechanism-based inhibitor of aTS, representing a new template for drug design and opening new possibilities for chemotherapy of Chagas' disease, as well as for the elucidation of aTS function in T. cruzi pathogenesis and biology.


Asunto(s)
Inhibidores Enzimáticos/farmacología , Glicoproteínas/antagonistas & inhibidores , Interacciones Huésped-Parásitos/efectos de los fármacos , Neuraminidasa/antagonistas & inhibidores , Ácidos Siálicos/farmacología , Trypanosoma cruzi/enzimología , Trypanosoma cruzi/patogenicidad , Animales , Biocatálisis/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Inhibidores Enzimáticos/química , Glicoproteínas/química , Glicoproteínas/metabolismo , Simulación de Dinámica Molecular , Estructura Molecular , Neuraminidasa/química , Neuraminidasa/metabolismo , Ácidos Siálicos/química , Relación Estructura-Actividad , Trypanosoma cruzi/efectos de los fármacos
16.
Mem Inst Oswaldo Cruz ; 105(8): 949-56, 2010 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-21225189

RESUMEN

Human malignant malaria is caused by Plasmodium falciparum and accounts for almost 900,000 deaths per year, the majority of which are children and pregnant women in developing countries. There has been significant effort to understand the biology of P. falciparum and its interactions with the host. However, these studies are hindered because several aspects of parasite biology remain controversial, such as N- and O-glycosylation. This review describes work that has been done to elucidate protein glycosylation in P. falciparum and it focuses on describing biochemical evidence for N- and O-glycosylation. Although there has been significant work in this field, these aspects of parasite biochemistry need to be explored further.


Asunto(s)
Plasmodium falciparum/metabolismo , Procesamiento Proteico-Postraduccional , Proteínas Protozoarias/metabolismo , Glicosilación
17.
Curr Pharm Des ; 26(29): 3579-3600, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32186271

RESUMEN

BACKGROUND: Cancer is characterized by abnormal cell growth and considered one of the leading causes of death around the world. Pharmaceutical Nanotechnology has been extensively studied for the optimization of cancer treatment. OBJECTIVE: Comprehend the panorama of Pharmaceutical Nanotechnology in cancer treatment, through a survey about nanomedicines applied in clinical studies, approved for use and patented. METHODS: Acknowledged products under clinical study and nanomedicines commercialized found in scientific articles through research on the following databases: Pubmed, Science Direct, Scielo and Lilacs. Derwent tool was used for patent research. RESULTS: Nanomedicines based on nanoparticles, polymer micelles, liposomes, dendrimers and nanoemulsions were studied, along with cancer therapies such as Photodynamic Therapy, Infrared Phototherapy Hyperthermia, Magnetic Hyperthermia, Radiotherapy, Gene Therapy and Nanoimmunotherapy. Great advancement has been observed over nanotechnology applied to cancer treatment, mainly for nanoparticles and liposomes. CONCLUSION: The combination of drugs in nanosystems helps to increase efficacy and decrease toxicity. Based on the results encountered, nanoparticles and liposomes were the most commonly used nanocarriers for drug encapsulation. In addition, although few nanomedicines are commercially available, this specific research field is continuously growing.


Asunto(s)
Nanopartículas , Neoplasias , Sistemas de Liberación de Medicamentos , Humanos , Liposomas/uso terapéutico , Micelas , Nanomedicina , Nanotecnología , Neoplasias/tratamiento farmacológico
18.
Curr Pharm Des ; 26(18): 2167-2181, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32072890

RESUMEN

BACKGROUND: Cancer is a set of diseases formed by abnormal growth of cells leading to the formation of the tumor. The diagnosis can be made through symptoms' evaluation or imaging tests, however, the techniques are limited and the tumor detection may be late. Thus, pharmaceutical nanotechnology has emerged to optimize the cancer diagnosis through nanostructured contrast agent's development. OBJECTIVE: This review aims to identify commercialized nanomedicines and patents for cancer diagnosis. METHODS: The databases used for scientific articles research were Pubmed, Science Direct, Scielo and Lilacs. Research on companies' websites and articles for the recognition of commercial nanomedicines was performed. The Derwent tool was applied for patent research. RESULTS: This article aimed to research on nanosystems based on nanoparticles, dendrimers, liposomes, composites and quantum dots, associated to imaging techniques. Commercialized products based on metal and composite nanoparticles, associated with magnetic resonance and computed tomography, have been observed. The research conducted through Derwent tool displayed a small number of patents using nanotechnology for cancer diagnosis. Among these patents, the most significant number was related to the use of systems based on metal nanoparticles, composites and quantum dots. CONCLUSION: Although few systems are found in the market and patented, nanotechnology appears as a promising field for the development of new nanosystems in order to optimize and accelerate the cancer diagnosis.


Asunto(s)
Nanopartículas , Nanoestructuras , Neoplasias , Sistemas de Liberación de Medicamentos , Humanos , Liposomas/uso terapéutico , Nanomedicina/métodos , Nanotecnología , Neoplasias/diagnóstico , Neoplasias/tratamiento farmacológico
19.
Cancer Immunol Res ; 8(10): 1262-1272, 2020 10.
Artículo en Inglés | MEDLINE | ID: mdl-32819969

RESUMEN

Diabetes mellitus (DM) significantly increases the risk for cancer and cancer progression. Hyperglycemia is the defining characteristic of DM and tightly correlates with a poor prognosis in patients with cancer. The hexosamine biosynthetic pathway (HBP) is emerging as a pivotal cascade linking high glucose, tumor progression, and impaired immune function. Here we show that enhanced glucose flow through the HBP drives cancer progression and immune evasion by increasing O-GlcNAcylation in tumor-associated macrophages (TAM). Increased O-GlcNAc skewed macrophage polarization to a M2-like phenotype supporting tumor progression. Finally, we found an upregulation of M2 markers on TAMs in DM2 patients with colorectal cancer compared with nondiabetic normoglycemic patients. Our results provide evidence for a new and targetable mechanism of cancer immune evasion in patients with hyperglycemia, advocating for strict control of hyperglycemia in patients with cancer.


Asunto(s)
Hiperglucemia/fisiopatología , Evasión Inmune/inmunología , Macrófagos/metabolismo , Animales , Modelos Animales de Enfermedad , Glicosilación , Humanos , Masculino , Ratones , Ratones SCID
20.
Eur J Pharm Sci ; 154: 105510, 2020 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-32801002

RESUMEN

The vital enzyme O-linked ß-N-acetylglucosamine transferase (OGT) catalyzes the O-GlcNAcylation of intracellular proteins coupling the metabolic status to cellular signaling and transcription pathways. Aberrant levels of O-GlcNAc and OGT have been linked to metabolic diseases as cancer and diabetes. Here, a new series of peptidomimetic OGT inhibitors was identified highlighting the compound LQMed 330, which presented better IC50 compared to the most potent inhibitors found in the literature. Molecular modeling study of selected inhibitors into the OGT binding site provided insight into the behavior by which these compounds interact with the enzyme. The results obtained in this study provided new perspectives on the design and synthesis of highly specific OGT inhibitors.


Asunto(s)
N-Acetilglucosaminiltransferasas , Peptidomiméticos , Acetilglucosamina , Modelos Moleculares , Peptidomiméticos/farmacología
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA