Die Analyse von Doxorubizin-beladenen Poly(butyl-cyanoacrylate)-Nanopartikeln in In-vitro-Glioma-Modellen

The use of doxorubicin for the treatment of glioma tumours would be an important approach in the chemotherapy treatment since doxorubicin is a very effective neoplastic agent. However, one problem faced by the use of doxorubicin for the treatment of brain tumours is the fact that doxorubicin is a substrate of an efflux pump protein, P-glycoprotein (P-gp), which is located on the luminal side of the brain capillary endothelium and in many tumour cells, which acts pumping out of the cell such substrate, and blocking its transport into the cell. A strategy to enhance the doxorubicin delivery into the brain would be the use of nanoparticles. This work showed, that the treatment of doxorubicin bound to poly(butyl cyanoacrylate) nanoparticles decreased the viability of the three glioma cell lines, the GS-9L, the RG-2, and the F-98 cell lines significantly in comparison to doxorubicin in solution, indicating an improvement of the nanoparticles-bound doxorubicin transport into the cells. The modification of the nanoparticles surface with different surfactants may even enhance the delivery of the drug into the cells. Searching for an improvement of the doxorubicin internalization, the nanoparticles surface was modified using polysorbate 80, poloxamer 188 and poloxamine 908 surfactants. The poloxamer 188 and polaxamine 908 surfactant modified nanoparticles did not show a significant enhancement of the doxorubicin internalization. Contrary, the treatment of polysorbate 80 surfactant modified nanoparticles led in some cases to a significant decrease of cancer cell viability. The use of doxorubicin in the three glioma cell lines allowed the measurement of different responses towards doxorubicin treatment. The different responses were due to the entry of various amounts of doxorubicin into the glioma cells, which express the P-glycoprotein in their cellular membrane. A higher level of the P-gp expression correlated with a weaker response towards the doxorubicin treatment. The GS-9L cell line showed a significant higher level of P-gp expression than the F-98, and RG-2 cell lines, and consequently, the GS-9L cell line presented the highest resistance to doxorubicin with the highest viability values after doxorubicin treatment. Due to the fact that the transport of doxorubicin is governed by the activity of the P-gp in the studied glioma cells, the use of poloxamer 185 as a P-gp inhibitor resulted in an enhancement of the uptake as well as of the accumulation of doxorubicin into the cells. The effect of poloxamer 185 on the doxorubicin uptake was significant marked in the case of doxorubicin-resistance cells, as the GS-9L cell line. In some cases, the presence of the nanoparticles formulation showed also an influence on such uptake improvement. The use of a P-gp inhibitor in combination with chemotherapeutic agents leads to encouraging results. Because of the wide spectrum of substances acting as P-gp inhibitors, the exact inhibitory mechanisms remain still unclear. For instance in our results the evaluation of a described P-gp inhibitor, polysorbate 80 did not show an important improvement in the doxorubicin uptake in the P-gp-expressing cell line, GS-9L. On the other hand, the Polysorbate 80-Dox-PBCA nanoparticles formulation decreased in greater extend the viability of the glioma cells than the poloxamer185-Dox-PBCA nanoparticles. Although, the P-gp inhibition was undoubtedly higher in the presence of poloxamer 185, polysorbate 80 showed a main effect on the disruption of the cellular membrane, resulting in an important cellular viability decrease. It seems that poloxamer 185 presents a direct effect on the functionality of the P-gp protein, which would be of great importance in the sensitization of resistant cancer cells. The range of concentration of poloxamer 185 is very important to yield an inhibitory effect on the P-gp-mediated transport mechanism. The accumulation of Rhodamine-123 (Rho-123), a known P-gp substrate, increased in a range of concentration from 0.001 % to 0.01, whereas at 0.1 % poloxamer 185 the accumulation significantly decreased. A maximal Rho-123 accumulation was reached at 0.01 % poloxamer 185.Die Verwendung von Doxorubicin stellt einen wichtigen therapeutischen Ansatz in der chemotherapeutischen Behandlung von Tumoren gliomalen Ursprungs dar, da sich Doxorubicin bereits als sehr effektiver neoplastischer Wirkstoff erwiesen hat. Es besteht jedoch das Problem, dass Doxorubicin durch das Multidrug Resistenzprotein P-gp, sowohl aus den Endothelzellen der Blut-Hirn Schranke, als auch aus Gerhirntumorzellen entfernt wird. P-gp ist in der Membran dieser Zellen lokalisiert und pumpt Doxorubicin und andere Substrate in einem ATP-abhängigen Prozess aus der Zelle. Eine Möglichkeit die Doxorubicin Applikation im Gehirn zu verbessern ist die Verwendung von Nanopartikeln. Diese Arbeit konnte zeigen, dass die Wirkung von Doxorubicin durch die Bindung an Poly(butyl-cyanoakrylat) Nanopartikel im Vergleich zu freiem Doxorubicin in Lösung signifikant gesteigert werden konnte. So konnte die Anzahl an lebenden Zellen durch eine Behandlung der Glioma Zelllinien GS-9L, RG-2 und F-98 mit Doxorubicin-beladenen Nanopartikeln signifikant erniedrigt werden, was für einen erhöhte effektive Doxorubicin-Konzentration in den Zellen spricht. Die Modifikation der Oberfläche der Nanopartikel mit unterschiedlichen Surfaktantien könnte das Einbringen von Doxorubicin in die Zielzellen zusätzlich erhöhen. Bei der Suche nach einer verbesserten Doxorubicin Internalisation wurde die Oberfläche der Nanopartikel mit Polysorbat 80, Poloxamar 188 und Poloxamin 908 Surfaktantien modifiziert. Die mit Poloxamer 188 und Polaxamin 908 Surfaktantien modifizierten Nanopartikel zeigten keine signifikante Verbesserung der Doxorubicin Internalisation in die Zellen. Im Gegensatz dazu konnte eine signifikante Reduktion der lebenden Krebszellen durch die Behandlung von Polysorbat 80-modifizierten Nanopartikeln beobachtet werden. Die Behandlung von drei unterschiedlichen Glioma Zelllinien mit Doxorubicin erlaubte verschiedene Wirkungen von Doxorubicin zu beobachten. Die verschiedenen Wirkungen wurden durch eine unterschiedliche Aufnahme von Doxorubicin in diese Zellen verursacht, die das P-gp Protein in ihrer Zellmembran exprimieren. Hierbei korrelierte eine erhöhte P-gp Expression mit einer schwächeren Doxorubicin Wirkung. Die Zelllinie GS-9L zeigte eine signifikant höhere P-pg Expression als die F-98 und RG-2 Zellen. Konsequenterweise wurde in dieser Zelllinie die höchste Doxorubicin Resistenz ermittelt mit den höchsten Werten an überlebenden Zellen nach Doxorubicin Behandlung. Da der Transport von Doxorubicin aus den Glioma Zellen mit der Aktivität des P-gp Proteins korreliert, konnte durch die Verwendung des P-gp Inhibitors Poloxamer 185 eine verbesserte Aufnahme und Akkumulation von Doxorubicin in den Zellen erreicht werden. Dieser Effekt der verbesserten Doxorubicin Aufnahme konnte besonders gut in den Doxorubicin-resistenten GS-9L Zellen beobachtet werden. In einigen Fällen konnte auch ein verbesserte Aufnahme durch die Verwendung der Nanopartikel beobachtet werden. Die Verwendung von P-gp Inhibitoren in Kombination mit chemotherapeutischen Agentien führten zu ermutigenden Resultaten. Durch das grosse Spektrum an Substanzen die in der Lage sind das P-gp Protein zu inhibieren, ist der exakte Mechanismus der Inhibition weiterhin ungeklärt. Zum Beispiel konnte die Verwendung des als P-gp Inhibitor beschriebenen Polysorbat 80, die Aufnahme von Doxorubicin in GS-9L Zellen nicht erhöhen. Allerdings wurde die Zahl an lebenden Glioma Zellen durch die Behandlung mit Polysorbat 80-dox-PBCA Nanopartikeln stärker reduziert, als durch die Behandlung mit Poloxamer 185-Dox-PBCA Nanopartikeln. Obwohl der Effekt der P-gp Inhibition in der Gegenwart von Poloxamer 185 höher war, zeigte Polysorbat 80 einen starken Effekt in der Zersetzung der Zellmembran, wodurch die Anzahl der lebenden Zellen stark vermindert werden konnte. Poloxamer 185 scheint hingegen einen direkten Einfluss auf die Funktionalität von P-gp auszuüben, wodurch es von großer Bedeutung für die Sensitivierung von resistenten Krebszellen sein könnte. Die Höhe der Poloxamer 185 Konzentration ist hierbei der entscheidende Parameter, um einen inhibitorischen Effekt auf den P-gp-vermittelten Transportmechanismus zu erzielen. Die Akkumulation von Rhodamin-123 (Rho-123), einem bekannten P-gp Substrat, konnte durch die Zugabe von 0,001 % bis 0,01 % stark erhöht werden, wobei ab einer Poloxamer 185 Konzentration von 0,1 % sich die Rho-123 Akkumulation signifikant reduzierte. Die maximale Rho-123 Akkumulation konnte bei einer Konzentration von 0,01 % Poloxamer 185 erreicht werden

Novel Functions of the Neurodegenerative-Related Gene Tau in Cancer

The analysis of global and comparative genomics between different diseases allows us to understand the key biological processes that explain the etiology of these pathologies. We have used this type of approach to evaluate the expression of several neurodegeneration-related genes on the development of tumors, particularly brain tumors of glial origin (gliomas), which are an aggressive and incurable type of cancer. We have observed that genes involved in Amyotrophic lateral sclerosis (ALS), as well as in Alzheimer's and Parkinson's diseases, correlate with better prognosis of gliomas. Within these genes, high Tau/MAPT expression shows the strongest correlation with several indicators of prolonged survival on glioma patients. Tau protein regulates microtubule stability and dynamics in neurons, although there have been reports of its expression in glial cells and also in gliomas. However, little is known about the regulation of Tau/MAPT transcription in tumors. Moreover, our in silico analysis indicates that this gene is also expressed in a variety of tumors, showing a general correlation with survival, although its function in cancer has not yet been addressed. Another remarkable aspect of Tau is its involvement in resistance to taxanes in various tumors types such as breast, ovarian and gastric carcinomas. This is due to the fact that taxanes have the same tubulin-binding site as Tau. In the present work we review the main knowledge about Tau function and expression in tumors, with a special focus on brain cancer. We will also speculate with the therapeutic implications of these findings.RG has been funded by the AECC Scientific Foundation. Research has been funded by grants from the Ministerio de Economía y Competitividad (MINECO-RETOS)/FEDER: SAF2015-65175-R to PS-G.S

Perception of climate change and farm level adaptation choices in central Kenya

Farmers are experiencing the need to adapt to climate change, and are developing different strategies. This article contributes to the understanding of farmers' adaptation choices, their determinants and their implications, in relation to the household income. In 2014, Focus Group Discussions (FGDs) and 220 household surveys were carried out with farmers in coffee and food crop zones in Central Kenya. The Heckman model was used to evaluate the determinants of adaptation choices and their marginal effect. Farmers from the coffee zone or from the food crop zone perceive and adapt differently to climate change. Farmers who are aware of changes in climate are more willing to explore adaptation strategies. A positive relationship is found between adaptation to climate change and household income. The highest payoff/return is achieved if multiple adaptation choices are used rather than a single strategy. The choices of strategies are also determined by household characteristics, resource endowment, institutional variables, and climate information. The strong correlation between socio-institutional variables and adaptation capacity suggests the need for the establishment and strengthening of local institutions, such as micro-finance and extension. (Résumé d'auteur

Modelling the continuous relaxation time spectrum of aquous xanthan solutions using two commercial softwares

The continuous relaxation time spectrum\ua0was modelled from the mechanical spectrum\ua0of a xanthan aqueous solution both using the\ua0TA Instruments TRIOS\uae software, and with\ua0the rheology software IRIS\uae1. Two types of\ua0calculation were applied to obtain the\ua0relaxation modes since the software bundles\ua0used in this study base the calculation upon\ua0two different algorithms, named\ua0"parsimonious" as it models continuous\ua0relaxation spectra using a minimum number\ua0of modes to obtain continuous relaxation\ua0times2, and a nonlinear regularization method that provides a larger spectrum with\ua0several modes3. The results were overall\ua0comparable but slightly different for long\ua0relaxation times

Datasets on technological GHG emissions mitigation options for the agriculture sector

The 2030 EU policy framework for climate and energy confirms that all sectors, including agriculture, should contribute to climate stabilisation and greenhouse gas (GHG) emission reduction in the most cost-effective way. Since 2009, the European Commission's Joint Research Centre (JRC) analyses the economic impact of GHG mitigation policy options for EU agriculture. However, the lack of precise, integrated and harmonised data on the current and potential uptake, cost-effectiveness and GHG emissions reduction potential of technological (i.e. technical and management based) mitigation options hampers the analysis of the economic impacts of GHG mitigation in agriculture. Against this background, the JRC organised a workshop in Seville on 14th June 2016 which gathered European Commission staff and experts from diverse international institutions aiming to: i) identify current activities conducted by research institutes on the building of datasets for GHG mitigation technologies and their state and development, ii) establish synergies and working mechanisms among the different institutions working on the topic, iii) identify which are the current gaps and limitations of existing datasets and models and, iv) conceive a roadmap to build possible new datasets per mitigation technology. The present report is based on the workshop results and concludes on how to move forward.JRC.D.4-Economics of Agricultur

Chronic IL-10 overproduction disrupts microglia-neuron dialogue similar to aging, resulting in impaired hippocampal neurogenesis and spatial memory

Altres ajuts: Acord transformatiu CRUE-CSICThis work was supported by the Spanish Ministry of Economy and Business (BFU2014-55459 and BFU2017-87843-R).The subgranular zone of the dentate gyrus is an adult neurogenic niche where new neurons are continuously generated. A dramatic hippocampal neurogenesis decline occurs with increasing age, contributing to cognitive deficits. The process of neurogenesis is intimately regulated by the microenvironment, with inflammation being considered a strong negative factor for this process. Thus, we hypothesize that the reduction of new neurons in the aged brain could be attributed to the age-related microenvironmental changes towards a pro-inflammatory status. In this work, we evaluated whether an anti-inflammatory microenvironment could counteract the negative effect of age on promoting new hippocampal neurons. Surprisingly, our results show that transgenic animals chronically overexpressing IL-10 by astrocytes present a decreased hippocampal neurogenesis in adulthood. This results from an impairment in the survival of neural newborn cells without differences in cell proliferation. In parallel, hippocampal-dependent spatial learning and memory processes were affected by IL-10 overproduction as assessed by the Morris water maze test. Microglial cells, which are key players in the neurogenesis process, presented a different phenotype in transgenic animals characterized by high activation together with alterations in receptors involved in neuronal communication, such as CD200R and CX3CR1. Interestingly, the changes described in adult transgenic animals were similar to those observed by the effect of normal aging. Thus, our data suggest that chronic IL-10 overproduction mimics the physiological age-related disruption of the microglia-neuron dialogue, resulting in hippocampal neurogenesis decrease and spatial memory impairment

Parkinson’s disease and autophagy

It is generally accepted that a correlation between neurodegenerative disease and protein aggregation in the brain exists; however, a causal relationship has not been elucidated. In neurons, failure of autophagy may result in the accumulation of aggregate-prone proteins and subsequent neurodegeneration. Thus, pharmacological induction of autophagy to enhance the clearance of intracytoplasmic aggregate-prone proteins has been considered as a therapeutic strategy to ameliorate pathology in cell and animal models of neurodegenerative disorders. However, autophagy has also been found to be a factor in the onset of these diseases, which raises the question of whether autophagy induction is an effective therapeutic strategy, or, on the contrary, can result in cell death. In this paper, we will first describe the autophagic machinery, and we will consider the literature to discuss the neuroprotective effects of autophagy

A Multiwavelength Consensus on the Main Sequence of Star-Forming Galaxies at z~2

We compare various star formation rate (SFR) indicators for star-forming galaxies at $1.4<z<2.5$ in the COSMOS field. The main focus is on the SFRs from the far-IR (PACS-Herschel data) with those from the ultraviolet, for galaxies selected according to the BzK criterion. FIR-selected samples lead to a vastly different slope of the SFR-stellar mass ($M_*$) relation, compared to that of the dominant main sequence population as measured from the UV, since the FIR selection picks predominantly only a minority of outliers. However, there is overall agreement between the main sequences derived with the two SFR indicators, when stacking on the PACS maps the BzK-selected galaxies. The resulting logarithmic slope of the SFR-{$M_*$} relation is $\sim0.8-0.9$, in agreement with that derived from the dust-corrected UV-luminosity. Exploiting deeper 24$\mu$m-Spitzer data we have characterized a sub-sample of galaxies with reddening and SFRs poorly constrained, as they are very faint in the $B$ band. The combination of Herschel with Spitzer data have allowed us to largely break the age/reddening degeneracy for these intriguing sources, by distinguishing whether a galaxy is very red in B-z because of being heavily dust reddened, or whether because star formation has been (or is being) quenched. Finally, we have compared our SFR(UV) to the SFRs derived by stacking the radio data and to those derived from the H$\alpha$ luminosity of a sample of star-forming galaxies at $1.4<z<1.7$. The two sets of SFRs are broadly consistent as they are with the SFRs derived from the UV and by stacking the corresponding PACS data in various mass bins.Comment: Accepted for publication in MNRA

Microenvironmental Snail1-induced immunosuppression promotes melanoma growth

Melanoma is an aggressive form of skin cancer due to its high metastatic abilities and resistance to therapies. Melanoma cells reside in a heterogeneous tumour icroenvironment that acts as a crucial regulator of its progression. Snail1 is an epithelial-tomesenchymal transition transcription factor expressed during development and reactivated in pathological situations including fibrosis and cancer. In this work, we show that Snail1 is activated in the melanoma microenvironment, particularly in fibroblasts. Analysis of mouse models that allow stromal Snail1 depletion and therapeutic Snail1 blockade indicate that targeting Snail1 in the tumour microenvironment decreases melanoma growth and lung metastatic burden, extending mice survival. Transcriptomic analysis of melanoma-associated fibroblasts and analysis of the tumours indicate that stromal Snail1 induces melanoma growth by promoting an immunosuppressive microenvironment and a decrease in anti-tumour immunity. This study unveils a novel role of Snail1 in melanoma biology and supports its potential as a therapeutic targe