Descifrando el mecanismo de inhibición de una pseudoquinasa: la quinasa ligada a integrinas y el cpd22 / Deciphering the inhibition mechanism of a pseudokinase: integrin-bound kinase and cpd22

Según la Organización Mundial de la Salud (OMS), el cáncer es una de las principales causas de muerte no infecciosas en todo el mundo. En este contexto, la búsqueda de nuevos fármacos potentes y seguros contra el cáncer es un área de gran interés para la industria farmacéutica y la investigación académica. A pesar de que las proteínas quinasas han sido una de las dianas anticancerosas más exploradas, sus parientes evolutivamente degenerado, las pseudoquinasas, han atraído la atención de la comunidad científica en la última década. La quinasa ligada a integrinas (ILK) es un miembro del pseudokinoma humano y ha sido reivindicada y validada como una diana terapéutica prometedora para las enfermedades neoplásicas. El único inhibidor de ILK conocido, CPD22, ha probado su actividad en ensayos fenotípicos; sin embargo, se dispone de muy poca información acerca de su mecanismo de acción a nivel molecular. Usando técnicas quimioinformáticas y de modelado molecular se ha dilucidado si el CPD22 es capaz de unirse a ILK y cómo lo hace. Además, nuestro modelo computacional explica el SAR generado en la campaña de optimización del cabeza de serie y los experimentos de SPR han probado, por primera vez, que la molécula se une a ILK, lo que respalda la hipótesis de inhibición por unión directa y el modelo generado. (AU)

According to World Health Organization (WHO) cancer is one of top non- infectious death causes worldwide. In this context, as such the searching of new potent and safe anticancer drugs is a hot point for pharmacy industry and academic investigation. Despite protein kinases have been one of the most explored anticancer targets, its evolutionary degenerated parents, pseudokinases, have attracted the attention of scientific community during the last decade. Integrin Linked Kinase (ILK) is a member of the human pseudokinome that has been claimed and validated as a prommissing target for neoplastic diseases. The only well-known ILK inhibitor, CPD22, has probed its activity in phenotypic assays, however very few knowledge regarding its mechanism of action at molecular level is available. Using chemoinformatic and molecular modelling techniques we were able to elucidate if this molecule is able to bind to ILK and how. Additionally, our model explains the SAR raised from the optimization campaign, and SPR experiments have probed, by first time, that this molecule binds to ILK, thus supporting the hypothesis of inhibition by direct binding and the computational model as well. (AU)

Statin-related myotoxicity / Miotoxicidad por estatinas

Statin therapy has a very important role in decreasing cardiovascular risk, and treatment non-compliance may therefore be a concern in high cardiovascular risk patients. Myotoxicity is a frequent side effect of statin therapy and one of the main causes of statin discontinuation, which limits effective treatment of patients at risk of or with cardiovascular disease. Because of the high proportion of patients on statin treatment and the frequency of statin-related myotoxicity, this is a subject of concern in clinical practice. However, statin-related myotoxicity is probably underestimated because there is not a gold standard definition, and its diagnosis is challenging. Moreover, information about pathophysiology and optimal therapeutic options is scarce. Therefore, this paper reviews the knowledge about the definition, pathophysiology and predisposing conditions, diagnosis and management of statin-related myotoxicity, and provides a practical scheme for its management in clinical practice (AU)

El tratamiento con estatinas tiene un papel fundamental en la reducción del riesgo cardiovascular, y la falta de adherencia al mismo es motivo de preocupación en los pacientes con alto riesgo. La miotoxicidad es un efecto secundario frecuente y una de las principales causas de interrupción de las estatinas, lo que limita el tratamiento eficaz de los pacientes con riesgo de enfermedad cardiovascular. Considerando la elevada proporción de pacientes en tratamiento con estatinas, y la frecuencia de miotoxicidad asociada, este es un tema relevante en la práctica clínica. Sin embargo, la miotoxicidad por las estatinas está probablemente subestimada debido a que no hay una definición bien establecida y su diagnóstico resulta difícil. Además, la información sobre la fisiopatología y las opciones terapéuticas óptimas es escasa. En este artículo revisamos la definición, fisiopatología y condiciones predisponentes, diagnóstico y tratamiento de la miotoxicidad por las estatinas, y proponemos un esquema práctico para su manejo (AU)

High pKDR immunohistochemical expression is an unfavourable prognostic biomarker in patients with advanced colorectal cancer treated with chemotherapy plus bevacizumab

Purpose: To analyse the prognostic role of the immunohistochemical expression of pKDR in patients with advanced colorectal cancer treated with oxaliplatin and fluoropyrimidines combination chemotherapy with or without bevacizumab. Methods: Retrospective multicentre study, carried out at four hospitals in the Valencian Community (Spain). Patients evolution was compared based on the immunohistochemical expression of pKDR, classified using 4 categories: 0 (undetectable), 1 (mild), 2 (moderate) and 3 (high intensity). Patients were divided into two groups for the analysis: group 1 with low expression (0-1) vs. group 2 with high expression (2-3). Results: Histological samples for the pKDR analysis were available for 84 of the 112 patients selected. Seven (8.3 %) had undetectable or mild expression of pKDR (Group 1) and 77 (91.7 %) showed moderate or high expression of pKDR (Group 2). Response rate in Group 1 was 100 %compared to 54.2 % in Group 2 (p = 0.019). Progression-free survival (PFS) (15 vs. 12 months, p = 0.4) and overall survival (OS) (28 vs. 22 months, p = 0.09) were numerically but not significantly higher in patients from Group 1 vs. Group 2. Patients from Group 2 who received bevacizumab presented a significantly higher PFS (13 vs. 11, p = 0.015) and a numerically higher OS (23 vs. 17 months, p = 0.27) than those treated exclusively with chemotherapy. Conclusions: Our results suggest that the absence or low expression of pKDR is associated with a better prognostic profile in patients with advanced colorectal cancer treated with chemotherapy and bevacizumab. Patients with a high pKDR expression benefit from the combination of chemotherapy with bevacizumab (AU)

No disponible

Los inhibidores de las proteínas-cinasas en enfermedades autoinmunes e inflamatorias: presente y futuro de nuevas dianas terapéuticas / Protein-kinase inhibitors: A new treatment pathway for autoimmune and inflammatory diseases?

Pese a los avances terapéuticos en las enfermedades autoinmunes e inflamatorias, muchos pacientes no logran un control adecuado de la enfermedad. De ahí la necesidad de optimizar el uso de las terapias biológicas y de explorar nuevas opciones terapéuticas. La disponibilidad de fármacos que inhiben proteínas-cinasas ya es una realidad en especialidades como oncología y hematología, donde los resultados asociados a la evolución clínica de la enfermedad han sido prometedores. La principal ventaja de estos fármacos es la administración oral, que podría favorecer la adherencia del paciente y reducir los costes asociados al tratamiento. Tofacitinib, inhibidor de tirosinas-cinasas, actualmente es el único fármaco de esta categoría aprobado para el tratamiento de la artritis reumatoide por la FDA. Estas dianas terapéuticas son evaluadas actualmente en diversas enfermedades autoinmunes e inflamatorias. Sin embargo, el conocimiento y la comprensión de las vías de señalización intracelular siguen siendo limitados, persistiendo dudas en cuanto al mecanismo de acción, la eficacia y los posibles efectos secundarios asociados al uso de estos nuevos fármacos (AU)

Although advances in biological medicine have seen significant progress in the treatment of autoimmune and inflammatory disease, many patients do not experience a satisfactory response. Hence, there are two challenges facing the medical research community. The first is to continue development in the field of existing biological therapies, such as monoclonal antibodies. The second is to open new frontiers of research and explore treatment alternatives for non-responders to other therapies. Attention has increasingly turned to the therapeutic potential of small molecule weight kinase inhibitors (SMKIs), currently used extensively in oncology and haematology. Initial research into the therapeutic value of SMKIs for autoimmune and inflammatory diseases has been encouraging. SMKIs are taken orally, which reduces cost for the health provider, and could increase compliance for the patient. This is why research is now focusing increasingly on SMKIs as a new generation line of treatment in these diseases. Tofacitinib, an inhibitor of Janus-kinase, is currently the only drug approved for the treatment of rheumatoid arthritis by FDA. However, much more needs to be done to understand the intracellular signalling pathways and how these might affect disease progression before solid conclusions can be drawn (AU)

Protein and Peptide in Drug Targeting and its Therapeutic Approach / Las proteínas y péptidos en la orientación de fármacos y su abordaje terapéutico

Aim. The main aim of this review article is to provide information like advantages of protein and peptides via different routes of drug administration, targeted to a particular site and its implication in drug delivery system. Methods. To that aim, from the web sites of PubMed, HCAplus, Thomson, and Registry were used as the main sources to perform the search for the most significant research articles published on the subject. The information was then carefully analyzed, highlighting the most important results in the development of protein and peptide drug targeting as well as its therapeutic activity. Results. In recent years many researchers use protein and peptide as a target site of drug by a different delivery system. Proteins and peptides are used as specific and effective therapeutic agents, due to instability and side effects their use is complicated. Protein kinases are important regulators of most, if not all, biological processes. Abnormal activity of proteins and peptides has been implicated in many human diseases, such as diabetes, cancer and neurodegenerative disorders. Conclusions. It is concluded that the protein and peptide were used in drug targeting to specific site and also used in different diseased states like cancer, diabetes, immunomodulating, neurodegenerative effects and antimicrobial activity

Objetivo. El objetivo principal de este artículo de revisión es proporcionar información sobre las ventajas de las proteínas y péptidos a través de diferentes vías de administración de fármacos, dirigidos a un sitio en particular y su implicación en el sistema de administración de fármacos. Métodos. Con ese objetivo, los sitios web de PubMed, HCAplus, Thomson, se utilizaron como las principales fuentes para realizar la búsqueda de los artículos de investigación más importantes publicados sobre el tema. La información fue luego cuidadosamente analizada, destacando los resultados más importantes en el desarrollo de proteína y péptido de direccionamiento de drogas, así como su actividad terapéutica. Resultados. En los últimos años muchos investigadores utilizan las proteínas y los péptidos como un sitio diana de fármaco por un sistema de administración diferente. Las proteínas y los péptidos se utilizan como agentes terapéuticos específicos y eficaces, debido a la inestabilidad y los efectos secundarios de su uso es complicado. Las proteínas quinasas son reguladores importantes de la mayoría, si no todos, los procesos biológicos. La actividad anormal de proteínas y péptidos se ha implicado en muchas enfermedades humanas, tales como diabetes, cáncer y trastornos neurodegenerativos. Conclusión. Finalmente concluyó que la proteína y el péptido se utilizaron en fármaco que se dirige al sitio específico y también se utiliza en diferentes estados de enfermedad como el cáncer, la diabetes, como sustancias inmunomoduladora, efectos neurodegenerativos y actividad antimicrobiana

Oxytocin activates calcium signaling in rat sensory neurons through a protein kinase C-dependent mechanism

In addition to its well-known effects on parturition and lactation, oxytocin (OT) plays an important role in modulation of pain and nociceptive transmission. But, the mechanism of this effect is unclear. To address the possible role of OT on pain modulation at the peripheral level, the effects of OT on intracellular calcium levels ([Ca2+]i) in rat dorsal root ganglion (DRG) neurons were investigated by using an in vitro calcium imaging system. DRG neurons were grown in primary culture following enzymatic and mechanical dissociation of ganglia from 1- or 2-day-old neonatal Wistar rats. Using the fura-2-based calcium imaging technique, the effects of OT on [Ca2+]i and role of the protein kinase C (PKC)-mediated pathway in OT effect were assessed. OT caused a significant increase in basal levels of [Ca2+]i after application at the doses of 30 nM (n = 34, p < 0.01), 100 nM (n = 41, p < 0.001) and 300 nM (n = 46, p < 0.001). The stimulatory effect of OT (300 nM) on [Ca2+]i was persistent in Ca2+-free conditions (n = 56, p < 0.01). Chelerythrine chloride, a PKC inhibitor, significantly reduced the OT-induced increase in [Ca2+]i (n = 28, p < 0.001). We demonstrated that OT activates intracellular calcium signaling in cultured rat primary sensory neurons in a dose- and PKC-dependent mechanism. The finding of the role of OT in peripheral pain modification may serve as a novel target for the development of new pharmacological strategies for the management of pain

Molecular mechanisms of cold-induced CYP1A activation in rat liver microsomes

No disponible

Cytochrome P4501A (the CYP1A1 and CYP1A2 enzymes) is known to metabolize anthropogenic xenobiotics to carcinogenic and mutagenic compounds. CYP1A1 transcriptional activation is regulated via the aryl hydrocarbon receptor (AhR)-dependent signal transduction pathway. CYP1A2 activation may occur through the AhR-dependent or AhR-independent signal transduction pathways. We used male Wistar rats to explore possible mechanisms of CYP1A activation induced by exposure to cold and the effects of the protein-tyrosine kinase inhibitors genistein, herbimycin A, and geldanamycin on the properties of hepatic CYP1A1 and CYP1A2 proteins following exposure to cold and to classic CYP1A inducers. The molecular mechanisms of cold-induced CYP1A1 and CYP1A2 activation are different. The CYP1A2 activation apparently occurs at the post-transcriptional level. The CYP1A1 activation, whether caused by exposure to cold or by classic CYP1A inducers, is AhR-dependent and occurs at the transcriptional level. Protein tyrosine kinase inhibitors have no effect on benzo(a)pyrene-induced CYP1A expression but alter cold-induced CYP1A1 activity and theCYP1A1 mRNA level. Thus, treatment with herbimycin A or geldanamycin leads to an increase in CYP1A1 activity, while treatment with genistein increases CYP1A1 mRNA expression and decreases CYP1A2 activity. These data elucidate the molecular mechanisms of cold-induced CYP1A activation and the role of protein kinases in the regulation of CYP1A during exposure to cold. Our results can also help identify the differences between the molecular mechanisms underlying the effects of the classic CYP1A inducers and the effects of cooling (AU)

Ezetimibe inhibe la adhesión y la migración de monocitos a través de la ruta de las proteincinasas activadas extracelularmente (p44/p42 ERK1/2 / Ezetimibe suppresses adhesion and chemotaxis of human monocytes through the p44/p42ERK1/2-dependent pathway

Introducción Recientemente nuestro grupo ha demostrado que ezetimibe, un inhibidor específico de la absorción intestinal, es capaz de inhibir la inflamación vascular en un modelo de arteriosclerosis en conejo. Nuestro objetivo ha sido investigar el efecto de ezetimibe sobre la adhesión y la migración de monocitos humanos THP-1, así como la participación de la vía de señalización de las proteincinasas activadas extracelularmente (p44/p42ERK1/2) sobre el efecto observado. Material y métodos La adhesión se valoró como la capacidad de las células THP-1 para unirse a placas de cultivo, y la migración se determinó con el empleo de cámaras de quimiotaxis. La expresión de moléculas de adhesión se cuantificó mediante citometría de flujo, y la activación de p44/p42ERK1/2 se estudió mediante Western Blot. Resultados La adhesión y la migración de los monocitos THP-1 inducidas con PMA o MCP-1, respectivamente, se inhibió de forma dependiente de la dosis al preincubar las células con ezetimibe. Además, el tratamiento con ezetimibe inhibió la expresión de las integrinas CD11a y CD11b, así como la fosforilación de p44/p42ERK1/2 (la forma activa) inducida por MCP-1. Más del 90% de las células (evaluadas mediante azul tripán) eran viables tras 1 ó 2 días de exposición a ezetimibe. Conclusiones Nuestros resultados indican que ezetimibe, además de su actividad hipolipemiante, puede inhibir el proceso de adhesión y migración de los monocitos. Parece que el bloqueo de la ruta de señalización de las MAPK p44/p42ERK1/2 podría estar implicado en el efecto observado (AU)

Introduction: Recently, our group has demonstrated that ezetimibe, a specific inhibitor of intestinal absorption, is able to inhibit vascular inflammation in a rabbit model of atherosclerosis. In this study, we investigated the effect of ezetimibe on the adhesion and migration of human THP-1 monocytes in vitro. We also studied the involvement of the MAP kinase signaling pathway,p44/p42ERK1/2, as a potential mechanism responsible for the observed effect. Material and methods: Adhesion of THP-1 monocytes was measured as the ability of cells tobind to plates. Migration was studied using two-compartment chambers. The expression of adhesion molecules was assessed by flow cytometry. Activation of p44/p42ERK1/2 was measured by Western Blot. Results: Preincubation of THP-1 monocytes with ezetimibe prevented PMA-induced adhesion and MCP-1-induced migration in a dose-dependent manner. Preincubation of THP-1 monocytes with ezetimibe also inhibited the expression of the integrins CD11a and CD11b, as well asphosphorylation of p-p44/p42ERK1/2 (the active form) induced by MCP-1. More than 90% of cells(evaluated through trypan blue) were viable 1 or 2 days after exposure to ezetimibe. Conclusions: Our results indicate that, in addition to its lipid lowering activity, ezetimibe isable to inhibit the process of adhesion and migration of monocytes in vitro. Blocking of thep44/p42ERK1/2 MAPK signalling pathway seems to play a role in this anti-inflammatory effect (AU)

Modulación de los receptores ionotrópicos de tipo cys-loop por proteincinasas A y C / Cys-loop ligand-gated ion channels modulation by protein kinases A and C

Introducción. En el sistema nervioso, la neurotransmisión química rápida es mediada por receptores ionotrópicos que se activan por la unión de su ligando. La unión del ligando a su receptor, favorece la entrada selectiva de iones a la célula que cambia el potencial eléctrico de la membrana celular. Los receptores de tipo cys-loop pertenecen a la superfamilia de receptores ionotrópicos activados por ligando que comprende a los receptores nicotínicos de acetilcolina, del ácido gamma-aminobutírico, glicina, serotonina y zinc. En diversos estudios se demostró que la actividad de estos receptores se modifica en respuesta a la activación de las proteincinasas A y C; los diferentes resultados, aparentemente contradictorios, podrían explicarse por la participación de diversos factores como el tipo de subunidades que forman a los receptores, componentes del citoesqueleto y subtipos de cinasas y fosfatasas presentes en el tejido nervioso de estudio. Objetivo. Presentar una revisión del efecto que las proteincinasas A y C ejercen sobre la actividad de los receptores ionotrópicos de tipo cys-loop. Desarrollo. En esta revisión se describen los experimentos obtenidos en diversas regiones en las que se ha determinado el efecto que tiene la activación de estas cinasas sobre la función de los receptores de neurotransmisores mayormente distribuidos en el sistema nervioso central y que han sido objeto de estudio. Conclusiones. La regulación de los receptores de tipo cys-loop por proteincinasas ocurre por medio de la activación de otros receptores (cross-talk) que se expresan en diversas etapas del desarrollo y áreas del sistema nervioso (AU)

Introduction. In the nervous system, rapid chemical neurotransmission is mediated by ionotropic receptors that are activated by ligand binding. Ligand binding to its receptor promotes the selective flow of ions into the cell which changes the electrical potential of the cell membrane. Cys-loop type receptors belong to the ligand-gated ion channel superfamily including the nicotinic acetylcholine receptor, the gamma-aminobutyric acid, glycine, serotonin and zinc. Several studies showed that the activity of these receptors was modified in response to protein kinases A and C activation; the different results, apparently contradictory, could be explained by the involvement of several factors such as the type of subunits that make up these receptors, components of the cytoskeleton and sub-types of kinases and phosphatases present in nerve tissue studied. Aim. To review the effect of protein kinases A and C on the activity of cys-loop receptors. Development. In this review we describe experiments conducted in different regions where it was determined the effect of these kinases on the function of neurotransmitter receptors mostly distributed in the nervous system. Conclusions. The cys-loop receptors regulation by protein kinases occurs through the activation of other receptors (crosstalk) that are expressed at different stages of development and nervous system areas (AU)

Differential expression of dnaA and dosRgenes among members of the Mycobacterium tuberculosis complex under oxic and hypoxic conditions

Major differences regarding the pathology and host immune response of the Beijing and Canettii genotypes of Mycobacterium tuberculosis have been reported; however, studies on the genetic expression of these genotypes during in vitro dormancy are scarce. This study examined the expression of five cell-cycle-related genes and two dormancy-related genes in M. canettii, M. tuberculosis H37Rv, and M. tuberculosis Beijing during the Wayne model of dormancy. The results showed that under hypoxic conditions the three tuberculosis genotypes were able to transcribe genes involved in DNA replication and cellular division. In addition, dosR was found to be up-regulated in M. tuberculosis Beijing during the exponential growth phase but down-regulated under hypoxic conditions. In this genotype, the replication-related gene dnaA was also strongly down-regulated. These latter two findings suggest that, compared to M. tuberculosis H37Rv and M. canettii, the Beijing genotype has a lower capacity to synthesize dosR, hspX, and dnaA mRNAs during in vitro dormancy (AU)

No disponible

Comprehensive lung injury pathology induced by mTOR inhibitors

Interstitial lung disease is a rare side effect of temsirolimus treatment in renal cancer patients. Pulmonary fibrosis is characterised by the accumulation of extracellular matrix collagen, fibroblast proliferation and migration, and loss of alveolar gas exchange units. Previous studies of pulmonary fibrosis have mainly focused on the fibroproliferative process in the lungs. However, the molecular mechanism by which sirolimus promotes lung fibrosis remains elusive. Here, we propose an overall cascade hypothesis of interstitial lung diseases that represents a common, partly underlying synergism among them as well as the lung pathogenesis side effects of mammalian target of rapamycin inhibitors (AU)

mTOR inhibitors and the anti-diabetic biguanide metformin: new insights into the molecular management of breast cancer resistance to the HER2 tyrosine kinase inhibitor lapatinib (Tykerb)

The small molecule HER2 tyrosine kinase inhibitor (TKI) lapatinib (Tykerb) is approved for the therapy of patients with HER2-positive breast carcinomas who have progressed on trastuzumab (Herceptin). Unfortunately, the efficacy of this HER2 TKI is limited by both primary (inherent) and acquired resistance, the latter typically occurring within 12 months of starting therapy. One of the key factors limiting our understanding of the mechanisms involved in lapatinib resistance is the lack of published preclinical models. We herein review lapatinib-refractory models recently developed at the bench and the survival pathways discovered. As hyperactivation of the pharmacologically targetable PI3K/mTOR/p70S6K1 axis appears to be central to the occurrence of lapatinib resistance, preclinical data showing enhanced antitumour effects when combining lapatinib with mTOR inhibitors (e.g., rapamycin analogues and NVP-BEZ235) highlight the importance of translational work to yield clinically useful regimens capable of delaying or treating lapatinib resistance. The unexpected ability of the anti-type II diabetes drug metformin to inactivate mTOR and decrease p70S6K1 activity further reveals that this biguanide, generally considered non-toxic and remarkably inexpensive, might be considered for new combinatorial lapatinib-based protocols in HER2-overexpressing breast cancer patients (AU)

Orexin A-induced extracellular calcium influx in prefrontal cortex neurons involves L-type calcium channels

Orexins, novel excitatory neuropeptides from the lateral hypothalamus, have beenstrongly implicated in the regulation of sleep and wakefulness. In this study, weexplored the effects and mechanisms of orexin A on intracellular free Ca2+ concentration([Ca2+]i) of freshly dissociated neurons from layers V and VI in prefrontalcortex (PFC). Changes in [Ca2+]i were measured with fluo-4/AM using confocallaser scanning microscopy. The results revealed that application of orexin A (0.1 ~1ìM) induced increase of [Ca2+]i in a dose-dependent manner. This elevation of[Ca2+]i was completely blocked by pretreatment with selective orexin receptor 1antagonist SB 334867. While depletion of intracellular Ca2+ stores by the endoplasmicreticulum inhibitor thapsigargin (2 ìM), [Ca2+]i in PFC neurons showed noincrease in response to orexin A. Under extracellular Ca2+-free condition, orexin Afailed to induce any changes of Ca2+ fluorescence intensity in these acutely dissociatedcells. Our data further demonstrated that the orexin A-induced increase of [Ca2+]iwas completely abolished by the inhibition of intracellular protein kinase C or phospholipaseC activities using specific inhibitors, BIS II (1 ìM) and D609 (10 ìM),respectively. Selective blockade of L-type Ca2+ channels by nifedipine (5 ìM) significantlysuppressed the elevation of [Ca2+]i induced by orexin A. Therefore, thesefindings suggest that exposure to orexin A could induce increase of [Ca2+]i in neuronsfrom deep layers of PFC, which depends on extracellular Ca2+ influx via L-typeCa2+ channels through activation of intracellular PLC-PKC signaling pathway bybinding orexin receptor 1(AU)

Activación de PP2A y alteraciones metabólicas inducidas por la ingestión de fructosa en forma líquida / PP2A activation and metabolic alterations induced by liquid fructose

Introducción: Dietas ricas en fructosa producen, en ratas, hipertrigliceridemia y esteatosis hepática, como consecuencia de una reducción en la actividad transcripcional del receptor activado con proliferadores peroxisómicos alfa (PPARa), junto con un estado de resistencia parcial a la leptina. En el presente trabajo, hemos estudiado cómo la fructosa afecta en el ámbito molecular al control del metabolismo energético hepático. Material y métodos: Se distribuyeron de forma aleatorizada a 16 ratas Sprague-Dawley macho en 2 grupos: control y fructosa (10% peso/volumen en agua de bebida, durante 14 días). Adicionalmente, se distribuyó a 12 ratas en 3 grupos: control, fructosa y fructosa + 1 ß-D ribofuranósido de 5-aminoimidazol 4-carboxamida (AICAR) (500 mg/kg/día, los últimos 3 días de dieta fructosa). Se valoraron los valores plasmáticos de triglicéridos, glucosa, leptina, insulina y adiponectina. En el ámbito hepático se determinaron: contenido de triglicéridos y ceramidas, actividad de ß-oxidación, actividad AMPK (AMP activada proteína cinasa), proteína fosfatasa 2A (PP2A) y valores de expresión proteica y de ácido ribonucleico mensajero de diferentes genes implicados en el metabolismo energético. Resultados: Las ratas del grupo fructosa presentaron hipertrigliceridemia (×1,3), hiperleptinemia (×1,9) e hiperadiponectinemia (×1,7), incremento en los triglicéridos (×1,6) y ceramidas hepáticas y en la formación de complejos PPARa-FoxO1. La administración de AICAR, aunque incrementó en un 30% la actividad AMPK hepática, no revirtió ninguna de las alteraciones descritas. En ratas fructosa no sometidas a ayuno antes del sacrificio, se detectó en hígado un marcado incremento en la subunidad catalítica de PP2A (×1,6) y en la capacidad de unión de ChREBP (×1,4). Conclusiones: El déficit de oxidación de ácidos grasos producido por el consumo de fructosa en forma líquida no es reversible por activación de la AMPK hepática. La activación de PP2A tras la ingesta de fructosa es la alteración molecular determinante en la aparición de los cambios metabólicos inducidos por este monosacárido (AU)

Introduction: Administration of fructoseenriched diets to rats induces hypertriglyceridemia and hepatic steatosis as a result of reduced PPARa transcriptional activity and partial leptin resistance. In the present work, we studied how fructose alters the control of hepatic energy metabolism at the molecular level. Material and methods: Sixteen Sprague-Dawley male rats were randomised to 2 treatment groups: control and fructose (10% w/v fructose in drinking water for 14 days). Additionally, 12 rats were distributed into 3 groups: control, fructose, and fructose+AICAR (500 mg/kg/day, in the last 3 days of fructose administration). Plasma levels of triglycerides, glucose, leptin, insulin and adiponectin were measured. Triglyceride and ceramide content, fatty acid ß-oxidation activity, AMPK and PP2A activity and expression of mRNA and protein levels of genes involved in energy metabolism were determined in liver samples. Results: Fructose-fed rats showed high plasma concentrations of triglycerides (×1.3), leptin (×1.9) and adiponectin (×1.7), an increase in hepatic triglycerides (×1.6) and ceramides and in the formation of PPARa-FoxO1 complexes. AICAR administration, despite increasing hepatic AMPK activity (×1.3), modified none of the above mentioned alterations. In livers of non-fasted fructose-fed rats, there was a marked increase in the expression of the catalytic subunit of PP2A (×1.6) and in the binding of ChREBP (×1.4). Conclusions: The deficit in liver fatty acid oxidation induced by fructose ingestion in liquid form is not reversed by the activation of AMPK. PP2A activation by fructose ingestion is the key molecular event in the production of fructoserelated metabolic changes (AU)

Angiogénesis neoplásica / Neoplastic angiogenesis

La angiogenésis neoplásica es un proceso esencial en el crecimiento progresivo de las neoplasias, y en la producción de metástasis. La angiogénesis consiste en una serie de complejos pasos consecutivos que conducen en último término al desarrollo de neovasos que aportan sangre a la masa tumoral. El VEGF tiene un papel primordial en la angiogénesis neoplásica, y por tanto es una importante diana en el tratamiento de las neoplasias. Bevacizumab, un anticuerpo monoclonal humano, inhibe el VEGF, y podría mejorar el transporte de la quimioterapia a las masas tumorales. Los inhibidores multi-kinasas (sorafenib y sunitinib) son pequeñas moléculas de administración oral, que inhiben diferentes receptores (esenciales en la angiogénesis neoplásica), como VEGFR o PDGFR. Estos agentes son útiles en el tratamiento del carcinoma de células renales avanzado, y están en investigación en muchos otros tumores

Neoplastic angiogenesis is an essential process in the progressive growth of neoplasms and the production of metastasis. Angiogenesis consists of a series of linked and sequential steps that ultimately leads to the development of a neovascular blood supply to the tumor mass. VEGF has got an essential role in neoplastic angiogenesis, there fore it is an important target in the treatment of neoplasms. Bevacizumab, a humanized monoclonal antibody, inhibits VEGF, and may also improve the delivery of chemotherapy to the tumor mass. Multi-kinase ihibitors (sorafenib and sunitinib) are orally administered small-molecules, that inhibit different receptors (essentials in the neoplastic angiogenesis), such as the VEGFR or PDGFR. These agents are useful in the treatment of advanced renal-cell carcinoma, and are under investigation in several tumors

La ‘marca sináptica’ y la huella de la memoriar / Synaptic tagging and memory trace

Presentar una visión de las principales características y posible identidad de la marca sináptica, así comodiscutir algunas de sus implicaciones funcionales. Desarrollo. La potenciación sináptica a largo plazo, dadas sus características, se ha impuesto como un modelo sinapticocelular de memoria muy atractivo. De modo similar a la memoria, puede manifestarse como temprana (dependiente fundamentalmente de la modificación de proteínas preexistentes en la sinapsis) otardía (dependiente de la síntesis de nuevas proteínas). Debido a que la potenciación sináptica a largo plazo es un fenómeno altamente específico, surge un dilema: ¿cómo llegan a las sinapsis apropiadas las proteínas requeridas para la estabilizacióndel cambio plástico en una neurona que normalmente posee miles de contactos sinápticos, todos dependientes del mismo núcleo? En este trabajo se presentan algunos de los modelos que aportan posibles soluciones a este interrogante, haciendo énfasisen la hipótesis del marcaje sináptico. Se exponen los principales hallazgos que han ido conformando esta hipótesis y se analiza la síntesis local y la activación de proteincinasas como posibles candidatos de ser la marca sináptica. Adicionalmente, sediscuten algunas implicaciones funcionales del marcaje sináptico. Conclusiones. La hipótesis de la marca sináptica ofrece una explicación muy flexible y razonable acerca de la especificidad del cambio sináptico duradero. Aunque se conocen algunas desus características, la identidad de la marca no se ha dilucidado aún. Al parecer, existen múltiples marcas que, al ser reclutadas por estímulos específicos, median los efectos plásticos en diferentes dominios temporales

To present a panorama of the main features and possible identity of the synaptic tag, such as to discuss someof its functional implications. Development. Long-term potentiation (LTP) constitutes a very attractive synaptic/cellular memory model. LTP, like memory, can manifest itself early (essentially depending on the modification of pre-existing proteins atsynapse) and late (depending on new protein synthesis). As LTP is a highly specific phenomenon, a dilemma arises: how can the proteins, required to plastic change stabilization, that are synthesized at the soma of a neuron containing thousands ofsynaptic contacts –all depending of the same nucleus– go to the appropriate synapses? In this review, we present some of the models that intend to explain this question, making emphasis on synaptic tagging hypothesis. Some of the main findings that have contributed to tagging hypothesis are exposed. The local protein synthesis and the activation of protein kinases areanalyzed as candidates to be the synaptic tag. Additionally, some of the functional implications of synaptic tagging are discussed. Conclusions. The synaptic tagging hypothesis offers a very flexible and reasonable solution to the specificity oflong-lasting synaptic changes. Although some of the tagging features are known, the synaptic tag identity has not yet been elucidated. It seems that there is not a unique synaptic tag, but there are rather multiple molecular synaptic tags involved.Each of them might function as a synaptic tag under particular circumstances. Each might be differentially recruited by specific stimuli and mediate plasticity over different time domains

Exantema severo por erlotinib (Tarceva (R)) / Erlotinib (Tarceva(R)) induced severe exanthema

No disponible

mTOR signalling in human cancer

Inhibitors of mTOR, the mammalian target of rapamycin, have been extensively studied in clinical trials for cancer treatment. Results have been promising, mostly in certain lymphomas, but in solid tumours the results have been generally less encouraging. However, recent results, particularly in renal cell carcinoma, have provided renewed interest in the role of mTOR inhibitors in solid tumours. A rational, and potentially more successful, development of these agents (i.e., RAD001, temsirolimus and AP23573) likely relies in a deeper knowledge of mTOR signalling in cancer, both at the preclinical and clinical levels. These would allow a better selection of patients more likely to respond to the use of biologically active doses of the agents and the development of mechanistically based combinations with other agents. The goal of this review is to provide an update on the complex signalling of mTOR in cancer and on the biological effects of mTOR inhibitors in cancer cells (AU)

Ritonavir incrementa la expresión de CD36 y ABCA1 en macrófagos THP-1 / Ritonavir increases CD36 and ABCA1 expression in THP-1 macrophages

El ritonavir es uno de los inhibidores de las proteasas que se utilizan como parte del tratamiento antirretroviral de gran actividad (TARGA) para la infección por el virus de la inmunodeficiencia humana, y su uso se ha asociado a un aumento en el riesgo de aterosclerosis prematura. Se ha propuesto que el ritonavir favorece la formación de células espumosas, aunque los estudios previos realizados han mostrado efectos contradictorios de este fármaco sobre las concentraciones del receptor scavenger CD36 en monocitos y macrófagos. Nuestros resultados muestran que el tratamiento con ritonavir a concentraciones dentro del rango terapéutico produce un incremento en la expresión de proteína y ARNm de CD36 en macrófagos THP-1 diferenciados, pero no en monocitos de la misma línea celular. Estas diferencias se podrían deber a la activación de la proteincinasa C producida tras la diferenciación con el éster de forbol PMA y la consiguiente activación de proliferadores de peroxisomas g (PPARg). Este mecanismo también explicaría el incremento en la expresión de ABCA1 hallado en nuestro estudio, aunque no la reducción de las concentraciones de proteína SR-BI, que no parece ser un efecto de tipo transcripcional. Finalmente, la inducción de PPARg y CD36 causada por el ritonavir no se asocia a un incremento en las concentraciones de la forma madura de SREBP1 (AU)

Ritonavir, a protease inhibitor used in highly active antiretroviral therapy (HAART) for HIV-1 infection, is associated with an increased risk of premature atherosclerosis. It has been proposed that ritonavir facilitates foam cell formation from macrophages, but conflicting results on the effect of this drug on CD36 scavenger receptor expression in monocytes and macrophages have been published. Our results show that ritonavir exposure at concentrations within the therapeutic range cause an increase in CD36 protein and mRNA levels in differentiated THP-1 macrophages, but not in monocytes from the same cell line. Protein kinase C (PKC) activation by the differentiating agent PMA and subsequent peroxisome proliferator-activated receptor-g (PPARg) activation could account for these differences. This mechanism could also explain the increase in ABCA1 expression found in our study, but not the decrease in SR-BI protein, which does not seem to be a transcriptional effect. Finally, PPARg and CD36 up-regulation by ritonavir are not related to an increase in levels of mature SREBP1 (AU)