SUMOylation regulates LKB1 localization and its oncogenic activity in liver cancer

BACKGROUND: Even though liver kinase B1 (LKB1) is usually described as a tumor suppressor in a wide variety of tissues, it has been shown that LKB1 aberrant expression is associated with bad prognosis in Hepatocellular Carcinoma (HCC). METHODS: Herein we have overexpressed LKB1 in human hepatoma cells and by using histidine pull-down assay we have investigated the role of the hypoxia-related post-translational modification of Small Ubiquitin-related Modifier (SUMO)ylation in the regulation of LKB1 oncogenic role. Molecular modelling between LKB1 and its interactors, involved in regulation of LKB1 nucleocytoplasmic shuttling and LKB1 activity, was performed. Finally, high affinity SUMO binding entities-based technology were used to validate our findings in a pre-clinical mouse model and in clinical HCC. FINDINGS: We found that in human hepatoma cells under hypoxic stress, LKB1 overexpression increases cell viability and aggressiveness in association with changes in LKB1 cellular localization. Moreover, by using site-directed mutagenesis, we have shown that LKB1 is SUMOylated by SUMO-2 at Lys178 hampering LKB1 nucleocytoplasmic shuttling and fueling hepatoma cell growth. Molecular modelling of SUMO modified LKB1 further confirmed steric impedance between SUMOylated LKB1 and the STe20-Related ADaptor cofactor (STRADα), involved in LKB1 export from the nucleus. Finally, we provide evidence that endogenous LKB1 is modified by SUMO in pre-clinical mouse models of HCC and clinical HCC, where LKB1 SUMOylation is higher in fast growing tumors. INTERPRETATION: Overall, SUMO-2 modification of LKB1 at Lys178 mediates LKB1 cellular localization and its oncogenic role in liver cancer. FUND: This work was supported by grants from NIH (US Department of Health and Human services)-R01AR001576-11A1 (J.M.M and M.L.M-C.), Gobierno Vasco-Departamento de Salud 2013111114 (to M.L.M.-C), ELKARTEK 2016, Departamento de Industria del Gobierno Vasco (to M.L.M.-C), MINECO: SAF2017-87301-R and SAF2014-52097-R integrado en el Plan Estatal de Investigación Cientifica y Técnica y Innovación 2013-2016 cofinanciado con Fondos FEDER (to M.L.M.-C and J.M.M., respectively), BFU2015-71017/BMC MINECO/FEDER, EU (to A.D.Q. and I.D.M.), BIOEF (Basque Foundation for Innovation and Health Research): EITB Maratoia BIO15/CA/014; Instituto de Salud Carlos III:PIE14/00031, integrado en el Plan Estatal de Investigación Cientifica y Técnica y Innovacion 2013-2016 cofinanciado con Fondos FEDER (to M.L.M.-C and J.M.M), Asociación Española contra el Cáncer (T.C.D, P·F-T and M.L.M-C), Daniel Alagille award from EASL (to T.C.D), Fundación Científica de la Asociación Española Contra el Cancer (AECC Scientific Foundation) Rare Tumor Calls 2017 (to M.L.M and M.A), La Caixa Foundation Program (to M.L.M), Programma di Ricerca Regione-Università 2007-2009 and 2011-2012, Regione Emilia-Romagna (to E.V.), Ramón Areces Foundation and the Andalusian Government (BIO-198) (A.D.Q. and I.D.M.), ayudas para apoyar grupos de investigación del sistema Universitario Vasco IT971-16 (P.A.), MINECO:SAF2015-64352-R (P.A.), Institut National du Cancer, FRANCE, INCa grant PLBIO16-251 (M.S.R.), MINECO - BFU2016-76872-R to (E.B.). Work produced with the support of a 2017 Leonardo Grant for Researchers and Cultural Creators, BBVA Foundation (M.V-R). Finally, Ciberehd_ISCIII_MINECO is funded by the Instituto de Salud Carlos III. We thank MINECO for the Severo Ochoa Excellence Accreditation to CIC bioGUNE (SEV-2016-0644). Funding sources had no involvement in study design; in the collection, analysis, and interpretation of data; in the writing of the report; and in the decision to submit the paper for publication

Enhanced Parallel Generation of Tree Structures for the Recognition of 3D Images

Segmentations of a digital object based on a connectivity criterion at n-xel or sub-n-xel level are useful tools in image topological analysis and recognition. Working with cell complex analogous of digital objects, an example of this kind of segmentation is that obtained from the combinatorial representation so called Homological Spanning Forest (HSF, for short) which, informally, classifies the cells of the complex as belonging to regions containing the maximal number of cells sharing the same homological (algebraic homology with coefficient in a field) information. We design here a parallel method for computing a HSF (using homology with coefficients in Z/2Z) of a 3D digital object. If this object is included in a 3D image of m1 × m2 × m3 voxels, its theoretical time complexity order is near O(log(m1 + m2 + m3)), under the assumption that a processing element is available for each voxel. A prototype implementation validating our results has been written and several synthetic, random and medical tridimensional images have been used for testing. The experiments allow us to assert that the number of iterations in which the homological information is found varies only to a small extent from the theoretical computational time.Ministerio de Economía y Competitividad MTM2016-81030-

The political hourglass: opportunistic behavior in local government policy decisions

The aim of this article is to determine whether there is opportunistic behavior in local government decisions related to contracting out, public-private partnership (PPP) and/or public externalization. Analysis of the results obtained from applying a fixed effects panel data model to a sample of 2,274 Spanish municipalities supports the existence of asymmetric opportunistic behavior. Specifically, there is strong evidence that in preelection years, there is less likelihood of contracting out and PPP decisions being approved, and a greater probability of public externalization taking place. In post-election years, an increase in capital spending is associated with a lower probability of contracting out and of PPP. An increase in current spending in preelection years reduces the probability of decisions being taken on contracting out and PPP. These empirical results highlight the extent of opportunistic behavior in selecting management forms for the delivery of local government services

Cost Minimization of Virtual Machine Allocation in Public Clouds Considering Multiple Applications

International Conference, GECON 2017 (14. 2017. Biarritz)This paper presents a virtual machine (VM) allocation strategy to optimize the cost of VM deployments in public clouds. It can simultaneously deal with multiple applications and it is formulated as an optimization problem that takes the level of performance to be reached by a set of applications as inputs. It considers real characteristics of infrastructure providers such as VM types, limits on the number VMs that can be deployed, and pricing schemes. As output, it generates a VM allocation to support the performance requirements of all the applications. The strategy combines short-term and long-term allocation phases in order to take advantage of VMs belonging to two different pricing categories: on-demand and reserved. A quantization technique is introduced to reduce the size of the allocation problem and, thus, significantly decrease the computational complexity. The experiments show that the strategy can optimize costs for problems that could not be solved with previous approache

A comparison of methods for the quality control of 123I-Ioflupane

Objetivos: Se pretende establecer un método sencillo, preciso y reproducible para determinar la pureza radioquímica del 123I-Ioflupano.Material y Métodos: Se utilizó la radiocromatografía con tres tipos de fases estacionarias (whatmann-17MM, Whatmann-3MM e ITLC-SG) y cinco fases móviles (Éter Dietílico, Metiletilcetona, NaCl al 0,9%, Metanol:Cloroformo(1:9), Metanol:Agua al 85%). Este procedimiento fue realizado con alícuotas de 123I-Ioflupano (DatScan®) y 123INa para estudiar el comportamiento del yoduro libre.Resultados: Se descartó el whatmann-3MM por su mala separación y el ITLC-SG con Metanol:Agua por su baja reproducibilidad. Usando Metiletilcetona como fase móvil en ITLC-SG y Whatmann-17MM no se observa la fracción libre. Únicamente se observó la fracción libre en Whatmann-17MM tanto con Metanol:Cloroformo como con Éter Dietílico y en ITLC-SG con NaCl 0,9% .Conclusiones: La mejor separación del 123I-Ioflupano del 123I- fue observada con: Whatmann-17MM/ Metanol:Cloroformo (1:9) (Rf de la fracción ligada = 0,62±0,03, Pureza Radioquímica = 91,6±2,36) , ITLC-SG/NaCl 0,9% (Rf de la fracción ligada = 0,21±0,05, Pureza Radioquímica = 90,19±3,4) y Whatmann-17MM /Éter Dietílico (Rf de la fracción ligada = 0,62±0,06, Pureza Radioquímica = 92,79±1,65).Aim: The aim of this study is to stablish an easy, reproducible, and precise method to determine the radiochemical purity of 123I-Ioflupane.Material and methods: Different systems of radiochromatography were used with three types of stationary phases (Whatmann-17MM, Whatmann-3MM and ITLC-SG) and five mobile phases (Diethylether, NaCl 0.9%, Methanol:Chloroform(1:9), Methanol:Water (85:15) and Methylethylketone). This procedure was made with samples of 123I-Ioflupane and 123I-NaI to study the behaviour of free iodide.Results: Whatmann-3MM was rejected due to an unsuccessful separation and Methanol:Water (85:15) with ITLC-SG was not reproducible. Free fraction wasn`t observed in Methylethylketone as mobile phase with ITLC-SG and Whatmann-17MM. Free fraction was just observed in Whatmann-17MM with Methanol:Cloroform and Diethylether and in ITLC-SG with NaCl 0.9%.Conclusions: Maximum separation between 123I-Ioflupane and 123I- was observed in Whatmann-17MM/Methanol:Cloroform(1:9) (Rf of bound fraction = 0.62±0.03, Radiochemical Purity =91.6±2.36%), ITLC-SG/NaCl 0,9% (Rf of bound fraction = 0.21±0.05, Radiochemical Purity =90.19±3.4%) and Whatmann-17MM/ Diethylether (Rf of bound fraction = 0.62±0.06, Radiochemical Purity =92.79±1.65%)

Gastrointestinal-Sparing Effects of Novel NSAIDs in Rats with Compromised Mucosal Defence

Nonsteroidal anti-inflammatory drugs are among the most commonly used prescription and over-the-counter medications, but they often produce significant gastrointestinal ulceration and bleeding, particularly in elderly patients and patients with certain co-morbidities. Novel anti-inflammatory drugs are seldom tested in animal models that mimic the high risk human users, leading to an underestimate of the true toxicity of the drugs. In the present study we examined the effects of two novel NSAIDs and two commonly used NSAIDs in models in which mucosal defence was expected to be impaired. Naproxen, celecoxib, ATB-346 (a hydrogen sulfide- and naproxen-releasing compound) and NCX 429 (a nitric oxide- and naproxen-releasing compound) were evaluated in healthy, arthritic, obese, and hypertensive rats and in rats of advanced age (19 months) and rats co-administered low-dose aspirin and/or omeprazole. In all models except hypertension, greater gastric and/or intestinal damage was observed when naproxen was administered in these models than in healthy rats. Celecoxib-induced damage was significantly increased when co-administered with low-dose aspirin and/or omeprazole. In contrast, ATB-346 and NCX 429, when tested at doses that were as effective as naproxen and celecoxib in reducing inflammation and inhibiting cyclooxygenase activity, did not produce significant gastric or intestinal damage in any of the models. These results demonstrate that animal models of human co-morbidities display the same increased susceptibility to NSAID-induced gastrointestinal damage as observed in humans. Moreover, two novel NSAIDs that release mediators of mucosal defence (hydrogen sulfide and nitric oxide) do not induce significant gastrointestinal damage in these models of impaired mucosal defence

Implicaciones anestésicas en el Síndrome de Larsen: A propósito de un caso

Larsen Syndrome (SL) is a rare hereditary disease characterized by a defect in the formation of collagen due to mutations in the genes encoding the cytoskeletal protein filamin B. Its prevalence in Europe is approximately 1 to 250,000 live births. This implies a number of anatomical features of the airway that we must assess in children who are going under anesthesia. We present the case of an 11-year-old boy diagnosed with Larsen syndrome who underwent left ear aticotomy. In this regard, we conducted a literature review on the peculiarities of anesthetic management of these patients.  El síndrome de Larsen (SL) es una enfermedad hereditaria rara caracterizada por un defecto en la formación de colágeno debido a mutaciones en los genes que codifican la proteína citoesquelética filamina B. Su prevalencia en Europa es aproximadamente de 1/250.000 nacidos vivos. Esto implica una serie de rasgos y particularidades anatómicas de la vía aérea que debemos valorar en niños que van a ser sometidos a un acto anestésico. Se presenta el caso de un niño de 11 años diagnosticado de síndrome de Larsen que se interviene de aticotomía oído izquierdo. A este propósito, realizamos revisión bibliográfica sobre las peculiaridades del manejo anestésico de estos pacientes

Usefulness of the Hepatocyte Growth Factor as a Predictor of Mortality in Patients Hospitalized With Acute Heart Failure Regardless of Ejection Fraction

Hepatocyte growth factor (HGF) plays a role in the improvement of cardiac function and remodeling. Their serum levels are strongly related with mortality in chronic systolic heart failure (HF). The aim of this study was to study prognostic value of HGF in acute HF, interaction with ejection fraction, renal function, and natriuretic peptides. We included 373 patients (age 76 ± 10 years, left ventricular ejection fraction [LVEF] 46 ± 14%, 48% men) consecutively admitted for acute HF. Blood samples were obtained at admission. All patients were followed up until death or close of study (>1 year, median 371 days). HGF concentrations were determined using a commercial enzyme-linked immunosorbent assay (human HGF immunoassay). The predictive power of HGF was estimated by Cox regression with calculation of Harrell C-statistic. HGF had a median of 1,942 pg/ml (interquartile rank 1,354). According to HGF quartiles, mortality rates (per 1,000 patients/year) were 98, 183, 375, and 393, respectively (p <0.001). In Cox regression analysis, HGF (hazard ratio1SD = 1.5, 95% confidence interval 1.1 to 2.1, p = 0.002) and N-terminal pro b-type natriuretic peptide (NT-proBNP; hazard ratio1SD = 1.8, 95% confidence interval 1.2 to 2.6, p = 0.002) were independent predictors of mortality. Interaction between HGF and LVEF, origin, and renal function was nonsignificant. The addition of HGF improved the predictive ability of the models (C-statistic 0.768 vs 0.741, p = 0.016). HGF showed a complementary value over NT-proBNP (p = 0.001): mortality rate was 490 with both above the median versus 72 with both below. In conclusion, in patients with acute HF, serum HGF concentrations are elevated and identify patients at higher risk of mortality, regardless of LVEF, ischemic origin, or renal function. HGF had independent and additive information over NT-proBNP

Random Walks on Stochastic Temporal Networks

In the study of dynamical processes on networks, there has been intense focus on network structure -- i.e., the arrangement of edges and their associated weights -- but the effects of the temporal patterns of edges remains poorly understood. In this chapter, we develop a mathematical framework for random walks on temporal networks using an approach that provides a compromise between abstract but unrealistic models and data-driven but non-mathematical approaches. To do this, we introduce a stochastic model for temporal networks in which we summarize the temporal and structural organization of a system using a matrix of waiting-time distributions. We show that random walks on stochastic temporal networks can be described exactly by an integro-differential master equation and derive an analytical expression for its asymptotic steady state. We also discuss how our work might be useful to help build centrality measures for temporal networks.Comment: Chapter in Temporal Networks (Petter Holme and Jari Saramaki editors). Springer. Berlin, Heidelberg 2013. The book chapter contains minor corrections and modifications. This chapter is based on arXiv:1112.3324, which contains additional calculations and numerical simulation