In vitro antitumor activity of methotrexate via pH-sensitive chitosan nanoparticles

Nanoparticles with pH-sensitive behavior may enhance the success of chemotherapy in many cancers by efficient intracellular drug delivery. Here, we investigated the effect of a bioactive surfactant with pH-sensitive properties on the antitumor activity and intracellular behavior of methotrexate-loaded chitosan nanoparticles (MTX-CS-NPs). NPs were prepared using a modified ionotropic complexation process, in which was included the surfactant derived from Nα,Nε-dioctanoyl lysine with an inorganic lithium counterion. The pH-sensitive behavior of NPs allowed accelerated release of MTX in an acidic medium, as well as membrane-lytic pH-dependent activity, which facilitated the cytosolic delivery of endocytosed materials. Moreover, our results clearly proved that MTX-CSNPs were more active against the tumor HeLa and MCF-7 cell lines than the free drug. The feasibilty of using NPs to target acidic tumor extracellular pH was also shown, as cytotoxicity against cancer cells was greater in a mildly acidic environment. Finally, the combined physicochemical and pH-sensitive properties of NPs generally allowed the entrapped drug to induce greater cell cycle arrest and apoptotic effects. Therefore, our overall results suggest that pH-sensitive MTX-CS-NPs could be potentially useful as a carrier system for tumor and intracellular drug delivery in cancer therapy.

Isolation of a novel monkey adenovirus reveals a new phylogenetic clade in the evolutionary history of simian adenoviruses

Adenoviruses of primates include human (HAdV) and simian (SAdV) isolates classified into 8 species (Human Adenovirus A to G, and Simian Adenovirus A). In this study, a novel adenovirus was isolated from a colony of cynomolgus macaques (Macaca fascicularis) and subcultured in VERO cells. Its complete genome was purified and a region encompassing the hexon gene, the protease gene, the DNA binding protein (DBP) and the 100 kDa protein was amplified by PCR and sequenced by primer walking. Sequence analysis of these four genes showed that the new isolate had 80% identity to other primate adenoviruses and lacked recombination events. The study of the evolutionary relationships of this new monkey AdV based on the combined sequences of the four genes supported a close relationship to SAdV-3 and SAdV-6, lineages isolated from Rhesus monkeys. The clade formed by these three types is separated from the remaining clades and establishes a novel branch that is related to species HAdV-A, F and G. However, the genetic distance corresponding to the newly isolated monkey AdV considerably differs from these as to belong to a new, not yet established species. Results presented here widen our knowledge on SAdV and represents an important contribution to the understanding of the evolutionary history of primate adenoviruses.

Isolation of a novel monkey adenovirus reveals a new phylogenetic clade in the evolutionary history of simian adenoviruses

Adenoviruses of primates include human (HAdV) and simian (SAdV) isolates classified into 8 species (Human Adenovirus A to G, and Simian Adenovirus A). In this study, a novel adenovirus was isolated from a colony of cynomolgus macaques (Macaca fascicularis) and subcultured in VERO cells. Its complete genome was purified and a region encompassing the hexon gene, the protease gene, the DNA binding protein (DBP) and the 100 kDa protein was amplified by PCR and sequenced by primer walking. Sequence analysis of these four genes showed that the new isolate had 80% identity to other primate adenoviruses and lacked recombination events. The study of the evolutionary relationships of this new monkey AdV based on the combined sequences of the four genes supported a close relationship to SAdV-3 and SAdV-6, lineages isolated from Rhesus monkeys. The clade formed by these three types is separated from the remaining clades and establishes a novel branch that is related to species HAdV-A, F and G. However, the genetic distance corresponding to the newly isolated monkey AdV considerably differs from these as to belong to a new, not yet established species. Results presented here widen our knowledge on SAdV and represents an important contribution to the understanding of the evolutionary history of primate adenoviruses.

Podocalyxin is a novel polysialylated neural adhesion protein with multiple roles in neural development and synapse formation

Neural development and plasticity are regulated by neural adhesion proteins, including the polysialylated form of NCAM (PSA-NCAM). Podocalyxin (PC) is a renal PSA-containing protein that has been reported to function as an anti-adhesin in kidney podocytes. Here we show that PC is widely expressed in neurons during neural development. Neural PC interacts with the ERM protein family, and with NHERF1/2 and RhoA/G. Experiments in vitro and phenotypic analyses of podxl-deficient mice indicate that PC is involved in neurite growth, branching and axonal fasciculation, and that PC loss-of-function reduces the number of synapses in the CNS and in the neuromuscular system. We also show that whereas some of the brain PC functions require PSA, others depend on PC per se. Our results show that PC, the second highly sialylated neural adhesion protein, plays multiple roles in neural development.

Temps de desig: la novel-la de Jeanne Hersch

L'única novel·la publicada per la filòsofa Jeanne Hersch (Temps alternés, 1942) consisteix principalment en una reflexió sobre el temps i sobre la relació del subjecte amb l'Altre. Descriu dos tipus de temporalitat: un present etern, en què la narradora adolescent viu l'instant sense plantejar-se cap fita, i un present de maduresa fet de records i de projeccions cap al futur. Exposa també dues possibilitats de relació entre el subjecte i l'Altre: la separació total, marcada per l'hermetisme del propi cos, i la fusió, encarnada en el cos porós de la dona embarassada. Aquestes alternatives es resumeixen en l'oposició entre amor i desig.

Temps de desig: la novel-la de Jeanne Hersch

L'única novel·la publicada per la filòsofa Jeanne Hersch (Temps alternés, 1942) consisteix principalment en una reflexió sobre el temps i sobre la relació del subjecte amb l'Altre. Descriu dos tipus de temporalitat: un present etern, en què la narradora adolescent viu l'instant sense plantejar-se cap fita, i un present de maduresa fet de records i de projeccions cap al futur. Exposa també dues possibilitats de relació entre el subjecte i l'Altre: la separació total, marcada per l'hermetisme del propi cos, i la fusió, encarnada en el cos porós de la dona embarassada. Aquestes alternatives es resumeixen en l'oposició entre amor i desig.

Emergence of novel domains in proteins

Proteins are composed of a combination of discrete, well-defined, sequence domains, associated with specific functions that have arisen at different times during evolutionary history. The emergence of novel domains is related to protein functional diversification and adaptation. But currently little is known about how novel domains arise and how they subsequently evolve. To gain insights into the impact of recently emerged domains in protein evolution we have identified all human young protein domains that have emerged in approximately the past 550 million years. We have classified them into vertebrate-specific and mammalian-specific groups, and compared them to older domains. We have found 426 different annotated young domains, totalling 995 domain occurrences, which represent about 12.3% of all human domains. We have observed that 61.3% of them arose in newly formed genes, while the remaining 38.7% are found combined with older domains, and have very likely emerged in the context of a previously existing protein. Young domains are preferentially located at the N-terminus of the protein, indicating that, at least in vertebrates, novel functional sequences often emerge there. Furthermore, young domains show significantly higher non-synonymous to synonymous substitution rates than older domains using human and mouse orthologous sequence comparisons. This is also true when we compare young and old domains located in the same protein, suggesting that recently arisen domains tend to evolve in a less constrained manner than older domains. We conclude that proteins tend to gain domains over time, becoming progressively longer. We show that many proteins are made of domains of different age, and that the fastest evolving parts correspond to the domains that have been acquired more recently.

EL Portafolio docente como estrategia formativa innovadora del profesorado novel universitario. Un estudio de casos

Este artículo sintetiza los resultados y las principales conclusiones de una investigación realizada en la Universidad de Barcelona sobre el tema del portafolio docente, un fenómeno bastante reciente en el campo de la formación del profesorado en general, y en la del docente universitario en particular. La introducción de esta herramienta en la Enseñanza universitaria se debe a la Asociación Canadiense de Profesores de Universidad (en la década de los ochenta), que la empleó para la habilitación y la evaluación de docentes. Sin embargo, en este trabajo se parte de la idea de que los portafolios docentes tienen también una vertiente formativa y resultan útiles en la mejora y el desarrollo profesional del profesorado universitario novel. Explorar este aspecto es el objetivo de nuestro estudio. Se ha elegido, como campo de aplicación, el profesorado novel de la Universidad de Barcelona, que ha elaborado un portafolio docente en los cursos de Iniciación en la Docencia Universitaria. El enfoque usado ha sido cualitativo y como estrategia metodológica hemos optado por el estudio de casos múltiple, dado que la muestra está constituida por 10 profesores universitarios noveles de diferentes áreas de conocimiento. Para recoger y registrar la información, los instrumentos empleados fueron la entrevista en profundidad y el análisis de documentos. Los resultados apuntan a que el verdadero valor del portafolio docente reside en su potencial formativo y para el desarrollo profesional del profesorado universitario novel. También revelan que el portafolio es una herramienta valiosa para un nuevo profesionalismo docente, que se orienta a la reflexión sobre la propia práctica docente y al desarrollo de una enseñanza más acorde con las exigencias de la nueva sociedad del conocimiento.

Networking of differentially expressed genes in human cancer cells resistant to methotrexate

BACKGROUND: The need for an integrated view of data obtained from high-throughput technologies gave rise to network analyses. These are especially useful to rationalize how external perturbations propagate through the expression of genes. To address this issue in the case of drug resistance, we constructed biological association networks of genes differentially expressed in cell lines resistant to methotrexate (MTX). METHODS: Seven cell lines representative of different types of cancer, including colon cancer (HT29 and Caco2), breast cancer (MCF-7 and MDA-MB-468), pancreatic cancer (MIA PaCa-2), erythroblastic leukemia (K562) and osteosarcoma (Saos-2), were used. The differential expression pattern between sensitive and MTX-resistant cells was determined by whole human genome microarrays and analyzed with the GeneSpring GX software package. Genes deregulated in common between the different cancer cell lines served to generate biological association networks using the Pathway Architect software. RESULTS: Dikkopf homolog-1 (DKK1) is a highly interconnected node in the network generated with genes in common between the two colon cancer cell lines, and functional validations of this target using small interfering RNAs (siRNAs) showed a chemosensitization toward MTX. Members of the UDP-glucuronosyltransferase 1A (UGT1A) family formed a network of genes differentially expressed in the two breast cancer cell lines. siRNA treatment against UGT1A also showed an increase in MTX sensitivity. Eukaryotic translation elongation factor 1 alpha 1 (EEF1A1) was overexpressed among the pancreatic cancer, leukemia and osteosarcoma cell lines, and siRNA treatment against EEF1A1 produced a chemosensitization toward MTX. CONCLUSIONS: Biological association networks identified DKK1, UGT1As and EEF1A1 as important gene nodes in MTX-resistance. Treatments using siRNA technology against these three genes showed chemosensitization toward MTX.

The redox state of cytochrome C modulates resistance to methotrexate in human MCF7 breast cancer cells

Background: Methotrexate is a chemotherapeutic agent used to treat a variety of cancers. However, the occurrence of resistance limits its effectiveness. Cytochrome c in its reduced state is less capable of triggering the apoptotic cascade. Thus, we set up to study the relationship among redox state of cytochrome c, apoptosis and the development of resistance to methotrexate in MCF7 human breast cancer cells. Results: Cell incubation with cytochrome c-reducing agents, such as tetramethylphenylenediamine, ascorbate or reduced glutathione, decreased the mortality and apoptosis triggered by methotrexate. Conversely, depletion of glutathione increased the apoptotic action of methotrexate, showing an involvement of cytochrome c redox state in methotrexateinduced apoptosis. Methotrexate-resistant MCF7 cells showed increased levels of endogenous reduced glutathione and a higher capability to reduce exogenous cytochrome c. Using functional genomics we detected the overexpression of GSTM1 and GSTM4 in methotrexate-resistant MCF7 breast cancer cells, and determined that methotrexate was susceptible of glutathionylation by GSTs. The inhibition of these GSTM isoforms caused an increase in methotrexate cytotoxicity in sensitive and resistant cells. Conclusions: We conclude that overexpression of specific GSTMs, GSTM1 and GSTM4, together with increased endogenous reduced glutathione levels help to maintain a more reduced state of cytochrome c which, in turn, would decrease apoptosis, thus contributing to methotrexate resistance in human MCF7 breast cancer cells.

Therapeutic targeting of tumor growth and angiogenesis with a novel anti-S100A4 monoclonal antibody

S100A4, a member of the S100 calcium-binding protein family secreted by tumor and stromal cells, supports tumorigenesis by stimulating angiogenesis. We demonstrated that S100A4 synergizes with vascular endothelial growth factor (VEGF), via the RAGE receptor, in promoting endothelial cell migration by increasing KDR expression and MMP-9 activity. In vivo overexpression of S100A4 led to a significant increase in tumor growth and vascularization in a human melanoma xenograft M21 model. Conversely, when silencing S100A4 by shRNA technology, a dramatic decrease in tumor development of the pancreatic MiaPACA-2 cell line was observed. Based on these results we developed 5C3, a neutralizing monoclonal antibody against S100A4. This antibody abolished endothelial cell migration, tumor growth and angiogenesis in immunodeficient mouse xenograft models of MiaPACA-2 and M21-S100A4 cells. It is concluded that extracellular S100A4 inhibition is an attractive approach for the treatment of human cancer.

Gone with the Wind and the Southern Way of Life: the Civil War as described in Margaret Mitchell’s Novel

This essay examines the American Civil War of 1861 – 1865, which is also known as the bloodiest war that the United States has ever experienced. The pretext for the war was the abolition of slavery in the South, and after many battles the Southern states lost: as a consequence, they experienced major changes in their economic and social life. This interesting piece from American history can be traced out throughout the characters’ lives in the novel Gone with the Wind which has been thoroughly analyzed in order to draw nearer and to comprehend the changes in the Southern way of life before and after the war. The author, Margaret Mitchell, was born in Atlanta, Georgia, and grew up with the stories about the war. As a result, Gone with the Wind studies not only its causes, but also the years after its end – a period which is not generally a subject of history and receives little attention – and the effects that such reversals have on former planters and slaves. From the position of contemporaneity, the reader can see that such changes in a society do not end with the laying down of an act, or in this case the end of the war, but they continue during many years; thus, the modern world can draw conclusions and lessons for events that are happening at the moment.

El profesorado novel de geografía e historia y el aprendizaje de tecnologías

Esta comunicación presenta un modelo de experiencia didáctica que se plantea el uso de tecnologiasdigitales y de internet en clase de Geografía e Historia a partir de los recursos tecnològicoshabituales que existan en un centro educativo y de los enseres tecnológicos que utilizaregularmente el alumnado.Se basa en diversas ejemplificaciones realizadas entre 2006 y 2013 con alumnado deGeografia e Historia del Màster de Secundaria de la UB, del antiguo CAP de Geografia e Historiadel ICE de la UB y de los cursos para profesorado novel interino del Departament d’Ensenyamentde la Generalitat de Catalunya. En la diversas actuaciones se fueron considerando losdiversos parámetros que finalmente han servido para determinar la estructura de la experienciaaplicada recientemente. Se trata de un modelo basado en tres apartados, donde el primeroes una exposición de tipo transmisivo que plantearía la teoria de toda la actividad a realizar.Una segunda parte propone un trabajo en grupo de descubrimiento tecnológico y deplanificación temática de la materia. Finalmente se fija una exposición del producto realizado como resultado del aprendizaje conseguido.

El profesorado novel de geografía e historia y el aprendizaje de tecnologías

Esta comunicación presenta un modelo de experiencia didáctica que se plantea el uso de tecnologiasdigitales y de internet en clase de Geografía e Historia a partir de los recursos tecnològicoshabituales que existan en un centro educativo y de los enseres tecnológicos que utilizaregularmente el alumnado.Se basa en diversas ejemplificaciones realizadas entre 2006 y 2013 con alumnado deGeografia e Historia del Màster de Secundaria de la UB, del antiguo CAP de Geografia e Historiadel ICE de la UB y de los cursos para profesorado novel interino del Departament d’Ensenyamentde la Generalitat de Catalunya. En la diversas actuaciones se fueron considerando losdiversos parámetros que finalmente han servido para determinar la estructura de la experienciaaplicada recientemente. Se trata de un modelo basado en tres apartados, donde el primeroes una exposición de tipo transmisivo que plantearía la teoria de toda la actividad a realizar.Una segunda parte propone un trabajo en grupo de descubrimiento tecnológico y deplanificación temática de la materia. Finalmente se fija una exposición del producto realizado como resultado del aprendizaje conseguido.