bluuebunny/crossref_metadata_2025 huggingface dataset:
Integrin β3 prevents apoptosis of HL-1 cardiomyocytes under conditions of oxidative stressThis article is one of a selection of papers published in a Special Issue on Oxidative Stress in Health and Disease.
Authors: Shewchuk Lee J. , Bryan Sean , Ulanova Marina , Khaper Neelam
Published: April 2010

Integrin receptors are essential in the regulation of vital cardiac functions, and impaired integrin activity has been associated with cardiac remodeling. Oxidative stress is known to be involved in apoptosis and cardiac remodeling and thus may profoundly influence cardiac function via integrin modulation. The aim of this study was to determine the expression pattern and functional role of integrins in HL-1 cardiomyocytes under conditions of oxidative stress. Gene expression was studied by end-point and real-time PCR; surface protein expression was studied by flow cytometry; integrin knockdown was accomplished by siRNA gene silencing; and apoptosis was studied by annexin V staining and active caspase-3/7 using flow cytometry. Among the various subunits under study (αv, α5, α6, and β1, β3, β4, and β5), the expression of β3 integrin was significantly increased at both the mRNA and protein levels in cardiomyocytes exposed to 100 µmol/L hydrogen peroxide for 3 h. Gene silencing of β3 integrin by using siRNA resulted in a 2-fold increase in cardiomyocyte apoptosis upon treatment with hydrogen peroxide. This increase in apoptosis, as measured by annexin V staining, correlated with an increase in active caspase-3/7. Integrin β3 plays a vital role in preventing cardiomyocyte apoptosis under conditions of oxidative stress.
Role of vasoactive peptides in high glucose-induced increased expression of Gαq/11 proteins and associated signaling in vascular smooth muscle cellsThis review is one of a selection of papers published in a Special Issue on Oxidative Stress in Health and Disease.
Authors: Descorbeth Magda , Anand-Srivastava Madhu B.
Published: April 2010

We have recently shown that A10 vascular smooth muscle cells (VSMCs) exposed to high glucose exhibited enhanced expression of Gαq and PLCβ proteins. Since high glucose has been reported to increase the levels of vasoactive peptides and oxidative stress, the present study was undertaken to investigate the implication of angiotensin II (Ang II), endothelin (ET)-1, and oxidative stress in the high glucose-induced enhanced expression of Gαq/11 and PLCβ proteins and associated signaling in A10 VSMCs. The levels of Gαq, Gα11, PLCβ-1, and PLCβ-2 proteins, as determined by Western blotting, were significantly higher in A10 VSMCs exposed to high glucose than in control cells. The elevated levels were restored to control values by the antioxidant diphenyleneiodonium (DPI), as well as by the antagonist of Ang II AT1 receptor losartan and the antagonists of ETA and ETB receptors BQ123 and BQ788, respectively. In addition, ET-1-stimulated production of inositol trisphosphate (IP3), which was enhanced by high glucose, was also restored toward control levels by DPI. Furthermore, the enhanced production of superoxide anion (O2–), increased NADPH oxidase activity, and enhanced expression of p22phox and p47phox proteins induced by high glucose were restored to control levels by losartan, BQ123, and BQ788. These results suggest that through increased oxidative stress, high glucose-induced enhanced levels of endogenous Ang II and ET-1 may contribute to the increased levels of Gαq/11 and mediated signaling in A10 VSMCs.
Functional linkage as a direction for studies in oxidative stress: α-adrenergic receptorsThis review is one of a selection of papers published in a Special Issue on Oxidative Stress in Health and Disease.
Authors: Ziolkowski Natalia , Grover Ashok K.
Published: April 2010

The α-adrenergic receptors (adrenoceptors) are activated by the endogenous agonists epinephrine and norepinephrine. They are G protein-coupled receptors that may be broadly classified into α1(subclasses α1A, α1B, α1D) and α2(subclasses α2A, α2B, α2C). The α1-adrenoceptors act by binding to Gαqsubunits of the G proteins, causing activation of phospholipase C (PLC). PLC converts phosphatidylinositol 4,5-bisphosphate into inositol trisphosphate (IP3) and diacylglycerol (DAG), which have downstream effects on cytosolic Ca2+concentration. The α2-adrenoceptors bind to Gαithus inhibiting adenylyl cyclase and decreasing cAMP levels. DAG alters protein kinase C activity and cAMP activates protein kinase A. The downstream pathways of the two receptors may also interact. Activation of α1- and α2-adrenoceptors in vascular smooth muscle results in vasoconstriction. However, the densities of individual receptor subclasses vary between vessel beds or between vessels of various sizes within the same bed. In vasculature, the densities of adrenoceptor subclasses differ between conduit arteries and arterioles. These differences, along with differences in coupling mechanisms, allow for fine regulation of arterial blood flow. This diversity is enhanced by interactions resulting from homo- and heterodimer formation of the receptors, metabolic pathways, and kinases. Reactive oxygen species generated in pathologies may alter α1- and α2-adrenoceptor cascades, change vascular contractility, or cause remodeling of blood vessels. This review emphasizes the need for understanding the functional linkage between α-adrenoceptor subtypes, coupling, cross talk, and oxidative stress in cardiovascular pathologies.
Oxidative stress: a key contributor to diabetic cardiomyopathyThis review is one of a selection of papers published in a Special Issue on Oxidative Stress in Health and Disease.
Authors: Khullar Madhu , Al-Shudiefat Abd Al-Rahman S. , Ludke Ana , Binepal Gursonika , Singal Pawan K.
Published: April 2010

Diabetes and its associated complications are major known health disorders. Diabetes mellitus increases the risk of cardiovascular morbidity and mortality by promoting cardiomyopathy. It appears to arise as a result of the diabetic state, at times independent of vascular or valvular pathology. It manifests initially as asymptomatic diastolic dysfunction, which progresses to symptomatic heart failure. The compliance of the heart wall is decreased and contractile function is impaired. The pathophysiology of diabetic cardiomyopathy is incompletely understood but appears to be multifactorial in origin. Several hypotheses have been proposed, including oxidative stress, inflammation, endothelial dysfunction, metabolic derangements, abnormalities in ion homeostasis, alterations in structural proteins, and interstitial fibrosis. Amongst these various mechanisms, an increase in reactive oxygen species, leading to oxidative stress, has received significant experimental support. This review focuses on the role of oxidative stress in the pathogenesis of diabetic cardiomyopathy and the potential of antioxidant therapy.
MULTIVARIATE TECHNIQUES FOR IDENTIFYING DIFFRACTIVE INTERACTIONS AT THE LHC
Authors: KUUSELA MIKAEL , LÄMSÄ JERRY W. , MALMI ERIC , MEHTÄLÄ PETTERI , ORAVA RISTO
Published: April 2010

Close to one half of the LHC events are expected to be due to elastic or inelastic diffractive scattering. Still, predictions based on extrapolations of experimental data at lower energies differ by large factors in estimating the relative rate of diffractive event categories at the LHC energies. By identifying diffractive events, detailed studies on proton structure can be carried out.

The combined forward physics objects: rapidity gaps, forward multiplicity and transverse energy flows can be used to efficiently classify proton–proton collisions. Data samples recorded by the forward detectors, with a simple extension, will allow first estimates of the single diffractive (SD), double diffractive (DD), central diffractive (CD), and nondiffractive (ND) cross-sections. The approach, which uses the measurement of inelastic activity in forward and central detector systems, is complementary to the detection and measurement of leading beam-like protons.

In this investigation, three different multivariate analysis approaches are assessed in classifying forward physics processes at the LHC. It is shown that with gene expression programming, neural networks and support vector machines, diffraction can be efficiently identified within a large sample of simulated proton–proton scattering events. The event characteristics are visualized by using the self-organizing map algorithm.
ON THE ISOMORPHIC DESCRIPTION OF CHIRAL SYMMETRY BREAKING BY NONUNITARY LIE GROUPS
Authors: BIETENHOLZ WOLFGANG
Published: April 2010

It is well known that chiral symmetry breaking (χSB) in QCD with Nf = 2 light quark flavors can be described by orthogonal groups as O (4) → O (3), due to local isomorphisms. Here we discuss the question how specific this property is. We consider generalized forms of χSB involving an arbitrary number of light flavors of continuum or lattice fermions, in various representations. We search systematically for isomorphic descriptions by nonunitary, compact Lie groups. It turns out that there are a few alternative options in terms of orthogonal groups, while we did not find any description entirely based on symplectic or exceptional Lie groups. If we adapt such an alternative as the symmetry breaking pattern for a generalized Higgs mechanism, we may consider a Higgs particle composed of bound fermions and trace back the mass generation to χSB. In fact, some of the patterns that we encounter appear in technicolor models. In particular if one observes a Higgs mechanism that can be expressed in terms of orthogonal groups, we specify in which cases it could also represent some kind of χSB of techniquarks.
ALGEBRAIC APPROACH TO SPIN SYMMETRY FOR THE DIRAC EQUATION WITH THE TRIGONOMETRIC SCARF POTENTIAL
Authors: WEI GAO-FENG , DUAN XIAO-YONG , LIU XU-YANG
Published: April 2010

By a simple algebraic approach we study the exact solution to the Dirac equation with scalar and vector trigonometric Scarf potentials in the case of spin symmetry. The transcendental energy equation and spinor wave functions are presented. It is found that there exist only positive energy bound states in the case of spin symmetry. Also, the energy eigenvalue approaches a constant when the potential parameter α goes to zero. The equally scalar and vector case is studied briefly.
NONSINGULAR BLACK HOLES FROM GRAVITY–MATTER-BRANE LAGRANGIANS
Authors: GUENDELMAN EDUARDO , KAGANOVICH ALEXANDER , NISSIMOV EMIL , PACHEVA SVETLANA
Published: April 2010

We consider self-consistent coupling of bulk Einstein–Maxwell–Kalb–Ramond system to codimension-one charged lightlikep-brane with dynamical (variable) tension (LL-brane). The latter is described by a manifestly reparametrization-invariant worldvolume action significantly different from the ordinary Nambu–Goto one. We show that the LL-brane is the appropriate gravitational and charge source in the Einstein–Maxwell–Kalb–Ramond equations of motion needed to generate a self-consistent solution describing nonsingular black hole. The latter consists of de Sitter interior region and exterior Reissner–Nordström region glued together along their common horizon (it is the inner horizon from the Reissner–Nordström side). The matching horizon is automatically occupied by the LL-brane as a result of its worldvolume Lagrangian dynamics, which dynamically generates the cosmological constant in the interior region and uniquely determines the mass and charge parameters of the exterior region. Using similar techniques we construct a self-consistent wormhole solution of Einstein–Maxwell system coupled to electrically neutral LL-brane, which describes two identical copies of a nonsingular black hole region being the exterior Reissner–Nordström region above the inner horizon, glued together along their common horizon (the inner Reissner–Nordström one) occupied by the LL-brane. The corresponding mass and charge parameters of the two black hole "universes" are explicitly determined by the dynamical LL-brane tension. This also provides an explicit example of Misner–Wheeler "charge without charge" phenomenon. Finally, this wormhole solution connecting two nonsingular black holes can be transformed into a special case of Kantowski–Sachs bouncing cosmology solution if instead of Reissner–Nordström we glue together two copies of the exterior Reissner–Nordström–de Sitter region with big enough bare cosmological constant, such that the radial coordinate becomes a timelike variable everywhere in the two "universes," except at the matching hypersurface occupied by the LL-brane.
THE ALL-SILICON STRIP CMS TRACKER: MICROTECHNOLOGY AT THE MACROSCALE
Authors: MANNELLI M.
Published: April 2010

The CMS silicon strip tracker is the largest device of its kind ever built, and is the first instance of a large collider detector relying exclusively on this all-silicon technology for tracking. With an instrumented surface of over 200 m2, and over nine million readout channels, it is two orders of magnitude larger than the silicon vertex detectors of the LEP experiments, and 30–40 times larger than the silicon inner detectors of the CDF and D0 experiments at the Tevatron. It makes use of microelectronics technology, but deploys it at the macroscale.

The photograph below shows the completed CMS silicon tracker, ready for installation in the experiment, side by side with the silicon strip vertex detector of the OPAL experiment at LEP. Approximately a decade and more than two orders of magnitude in scale separate these two silicon strip detectors.

[Formula: see text]

In the following we motivate the choice of an all-silicon tracker for the CMS experiment, and discuss the reasons for the major design choices that define the system.
Effects of atorvastatin on the regeneration of pancreatic β-cells after streptozotocin treatment in the neonatal rodent
Authors: Marchand K. C. , Arany E. J. , Hill D. J.
Published: April 2010

To investigate the role of statins in β-cell regeneration a model of streptozotocin (STZ)-induced β-cell injury was used in the neonatal rat. We hypothesized that β-cell growth and regeneration would increase following treatment with atorvastatin and that this would be associated with intraislet vasculogenesis. Pregnant Wistar rats were gavaged with 20 or 40 mg/kg atorvastatin for 21 days commencing on gestation day 15. Atorvastatin was detected in the circulation of the offspring. On postnatal day 4, the pups were given either a control or STZ (70 mg/kg ip) injection. β-Cell mass had partially recovered by postnatal day 44 following STZ treatment, and atorvastatin (20 mg/kg) significantly increased β-cell mass in both STZ-treated and control animals. An increase in the numbers of small islets at postnatal day 44 was seen in STZ-treated animals following atorvastatin, suggestive of neogenesis, and glucose tolerance was improved. Treatment with atorvastatin caused an increase in the numbers of intraislet endothelial cells at postnatal day 14 and the percentage of endothelial cells undergoing DNA synthesis, suggesting that angiogenesis had preceded the increase in β-cell mass. The results indicate that functional β-cell mass was expanded with atorvastatin in both control and STZ-treated neonatal rats and suggests a novel effect of a statin in promoting islet plasticity.
Skeletal muscle protein balance in mTOR heterozygous mice in response to inflammation and leucine
Authors: Lang Charles H. , Frost Robert A. , Bronson Sarah K. , Lynch Christopher J. , Vary Thomas C.
Published: April 2010

Sepsis and lipopolysaccharide (LPS) may decrease skeletal muscle protein synthesis by impairing mTOR (mammalian target of rapamycin) activity. The role of mTOR in regulating muscle protein synthesis was assessed in wild-type (WT) and mTOR heterozygous (+/−) mice under basal conditions and in response to LPS and/or leucine stimulation. No difference in body weight of mTOR+/−mice was observed compared with WT mice; whereas whole body lean body mass was reduced. Gastrocnemius weight was decreased in mTOR+/−mice, which was attributable in part to a reduced rate of basal protein synthesis. LPS decreased muscle protein synthesis in WT and mTOR+/−mice to the same extent. Reduced muscle protein synthesis in mTOR+/−mice under basal and LPS-stimulated conditions was associated with lower 4E-BP1 and S6K1 phosphorylation. LPS also decreased PRAS40 phosphorylation and increased phosphorylation of raptor and IRS-1 (Ser307) to the same extent in WT and mTOR+/−mice. Muscle atrogin-1 and MuRF1 mRNA content was elevated in mTOR+/−mice under basal conditions, implying increased ubiquitin-proteasome-mediated proteolysis, but the LPS-induced increase in these atrogenes was comparable between groups. Plasma insulin and IGF-I as well as tissue expression of TNFα, IL-6, or NOS2 did not differ between WT and mTOR+/−mice. Finally, whereas LPS impaired the ability of leucine to stimulate muscle protein synthesis and 4E-BP1 phosphorylation in WT mice, this inflammatory state rendered mTOR+/−mice leucine unresponsive. These data support the idea that the LPS-induced reduction in mTOR activity is relatively more important in regulating skeletal muscle mass in response to nutrient stimulation than under basal conditions.
NMDAR-Dependent Control of Call Duration in Xenopus laevis
Authors: Zornik Erik , Katzen Abraham W. , Rhodes Heather J. , Yamaguchi Ayako
Published: April 2010

Many rhythmic behaviors, such as locomotion and vocalization, involve temporally dynamic patterns. How does the brain generate temporal complexity? Here, we use the vocal central pattern generator (CPG) of Xenopus laevis to address this question. Isolated brains can elicit fictive vocalizations, allowing us to study the CPG in vitro. The X. laevis advertisement call is temporally modulated; calls consist of rhythmic click trills that alternate between fast (∼60 Hz) and slow (∼30 Hz) rates. We investigated the role of two CPG nuclei—the laryngeal motor nucleus (n.IX–X) and the dorsal tegmental area of the medulla (DTAM)—in setting rhythm frequency and call durations. We discovered a local field potential wave in DTAM that coincides with fictive fast trills and phasic activity that coincides with fictive clicks. After disrupting n.IX–X connections, the wave persists, whereas phasic activity disappears. Wave duration was temperature dependent and correlated with fictive fast trills. This correlation persisted when wave duration was modified by temperature manipulations. Selectively cooling DTAM, but not n.IX–X, lengthened fictive call and fast trill durations, whereas cooling either nucleus decelerated the fictive click rate. The N-methyl-d-aspartate receptor (NMDAR) antagonist dAPV blocked waves and fictive fast trills, suggesting that the wave controls fast trill activation and, consequently, call duration. We conclude that two functionally distinct CPG circuits exist: 1) a pattern generator in DTAM that determines call duration and 2) a rhythm generator (spanning DTAM and n.IX–X) that determines click rates. The newly identified DTAM pattern generator provides an excellent model for understanding NDMAR-dependent rhythmic circuits.
Genetic locus on MWF rat chromosome 6 affects kidney damage in response tol-NAME treatment in spontaneously hypertensive rats
Authors: Schulz Angela , Schütten Sabrina , Schulte Leonard , Kossmehl Peter , Nyengaard Jens R. , Vetter Roland , Huber Matthias , Kreutz Reinhold
Published: April 2010

A major quantitative trait locus (QTL) on rat chromosome (RNO)6 was linked to albuminuria in Munich Wistar Frömter rats (MWF). We tested whether transfer of MWF RNO6 into the background of albuminuria-resistant spontaneously hypertensive rats (SHR) induces albuminuria in consomic SHR-6MWFanimals. Male MWF, SHR, and SHR-6MWFwere sham operated and treated between 6 and 24 wk of age with normal water (Sham) or with water containing 20 mg/l NG-nitro-l-arginine methyl ester (l-NAME) or unilaterally nephrectomized (Nx). Compared with SHR albuminuria was not increased in SHR-6MWFin both Sham and Nx groups. All animals survived the observation period in Sham and Nx groups, while premature mortality occurred from 12–14 wk on in l-NAME-treated SHR and SHR-6MWFcompared with MWF l-NAME animals, in which survival was not affected ( P < 0.005, respectively). Subsequent further analysis of l-NAME-treated animals at 12 wk of age showed significantly increased arterial blood pressures in both SHR and SHR-6MWFcompared with control ( P < 0.05), with higher levels in SHR compared with consomics ( P < 0.05). However, l-NAME-treated consomic animals demonstrated increased albuminuria compared with SHR (12.7 ± 3.5 vs. 0.8 ± 0.2 mg/24 h; P < 0.05) and an induction of tubulointerstitial structural injury and expression of neutrophil gelatinase-associated lipocalin mRNA ( P < 0.05 vs. other strains). Our study demonstrates that isolation of the RNO6 albuminuria QTL from the MWF background and transfer into SHR fails to induce an albuminuria phenotype during normal conditions or after nephron reduction. Moreover, our data indicate that genes on RNO6 contribute to the development of l-NAME-induced renal damage in the SHR strain.
Bovine pretransfer endometrium and embryo transcriptome fingerprints as predictors of pregnancy success after embryo transfer
Authors: Salilew-Wondim Dessie , Hölker Michael , Rings Franca , Ghanem Nasser , Ulas-Cinar Mehmet , Peippo Jaana , Tholen Ernst , Looft Christian , Schellander Karl , Tesfaye Dawit
Published: April 2010

Aberrant gene expression in the uterine endometrium and embryo has been the major causes of pregnancy failure in cattle. However, selecting cows having adequate endometrial receptivity and embryos of better developmental competence based on the gene expression pattern has been a greater challenge. To investigate whether pretransfer endometrial and embryo gene expression pattern has a direct relation with upcoming pregnancy success, we performed a global endometrial and embryo transcriptome analysis using endometrial and embryo biopsy technology and the pregnancy outcome information. For this, endometrial samples were collected from Simmental heifers at day 7 and 14 of the estrous cycle, one cycle prior to embryo transfer. In the next cycle, blastocyst stage embryos were transferred to recipients at day 7 of the estrous cycle after taking 30–40% of the blastocyst as a biopsy for transcriptome analysis. The results revealed that at day 7 of the estrous cycle, the endometrial gene expression pattern of heifers whose pregnancy resulting in calf delivery was significantly different compared with those resulting in no pregnancy. These differences were accompanied by qualitative and quantitative alteration of major biological process and molecular pathways. However, the transcriptome difference was minimal between the two groups of animals at day 14 of the estrous cycle. Similarly, the transcriptome analysis between embryos biopsies that resulted in calf delivery and those resulted in no pregnancy revealed a total of 70 differentially expressed genes. Among these, the transcript levels of 32 genes including SPAG17, PF6, UBE2D3P, DFNB31, AMD1, DTNBP1, and ARL8B were higher in embryo biopsies resulting in calf delivery. Therefore, the present study highlights the potential of pretransfer endometrial and embryo gene expression patterns as predictors of pregnancy success in cattle.
Intrauterine growth retardation affects expression and epigenetic characteristics of the rat hippocampal glucocorticoid receptor gene
Authors: Ke Xingrao , Schober Michelle E. , McKnight Robert A. , O'Grady Shannon , Caprau Diana , Yu Xing , Callaway Christopher W. , Lane Robert H.
Published: April 2010

Studies in humans and rats suggest that intrauterine growth retardation (IUGR) permanently resets the hypothalamic-pituitary-adrenal (HPA) axis. HPA axis reprogramming may involve persistently altered expression of the hippocampal glucocorticoid receptor (hpGR), an important regulator of HPA axis reactivity. Persistent alteration of gene expression, long after the inciting event, is thought to be mediated by epigenetic mechanisms that affect mRNA and mRNA variant expression. GR mRNA variants in both humans and rats include eleven 5′-end variants and GRα, the predominant 3′-end variant. The 3′-end variants associated with glucocorticoid resistance in humans (GRβ, GRγ, GRA, and GRP) have not been reported in rats. We hypothesized that in the rat hippocampus IUGR would decrease total GR mRNA, increase GRβ, GRγ, GRA, and GRP, and affect epigenetics of the GR gene at birth (D0) and at 21 days of life (D21). IUGR increased hpGR and exon 1.7 hpGR mRNA in males at D0 and D21, associated with increased trimethyl H3/K4 at exon 1.7 at both time points. IUGR also increased hpGRγ in males at D0 and D21, associated with increased acetyl H3/K9 at exon 3 at both time points. hpGRA increased in female IUGR rats at D0 and D21. In addition, our data support the existence of hpGRβ and hpGRP in the rat. IUGR has sex-specific, persistent effects on GR expression and its histone code. We speculate that postnatal changes in hippocampal GR variant and total mRNA expression may underlie IUGR-associated HPA axis reprogramming.
Epo Is Relevant Neither for Microvascular Formation Nor for the New Formation and Maintenance of Mice Skeletal Muscle Fibres in Both Normoxia and Hypoxia
Authors: Hagström Luciana , Agbulut Onnik , El-Hasnaoui-Saadani Raja , Marchant Dominique , Favret Fabrice , Richalet Jean-Paul , Beaudry Michèle , Launay Thierry
Published: April 2010

Erythropoietin (Epo) and vascular growth factor (VEGF) are known to be involved in the regulation of cellular activity when oxygen transport is reduced as in anaemia or hypoxic conditions. Because it has been suggested that Epo could play a role in skeletal muscle development, regeneration, and angiogenesis, we aimed to assess Epo deficiency in both normoxia and hypoxia by using an Epo-deficient transgenic mouse model (). Histoimmunology, ELISA and real time RT-PCR did not show any muscle fiber atrophy or accumulation of active HIF-1 but an improvement of microvessel network and an upregulation of VEGFR2 mRNA in Epo-deficient gastrocnemius compared with Wild-Type one. In hypoxia, both models exhibit an upregulation of VEGF120 and VEGFR2 mRNA but no accumulation of Epo protein. EpoR mRNA is not up-regulated in both Epo-deficient and hypoxic gastrocnemius. These results suggest that muscle deconditioning observed in patients suffering from renal failure is not due to Epo deficiency.
L6E9 Myoblasts Are Deficient of Myostatin and Additional TGF-βMembers Are Candidates to Developmentally Control Their Fiber Formation
Authors: Rossi Stefania , Stoppani Elena , Gobbo Massimiliano , Caroli Anna , Fanzani Alessandro
Published: April 2010

This work provides evidence that the robust myoblast differentiation observed in L6E9 cells is causally linked to deficiency of myostatin, which, conversely, has been found to be expressed in C2C12 cells. However, despite the absence of endogenous myostatin, L6E9 myoblasts expressed functional Activin receptors type II (ActRIIs) and follistatin as well as the highly related TGF-βmembers Activins and GDF11, suggesting that in this cell line the regulation of fiber size might be under the control of multiple regulators regardless of myostatin. In line with this hypothesis, delivery of a dominant-negative ActRIIb form or the increase of follistatin, as obtained via Trichostatin treatment or stable transfection of a short human follistatin form, enhanced the L6E9 cell differentiation and further increased the size of myotubes, suggesting that L6E9 myoblasts provide a spontaneous myostatin knock-out in vitro model to study TGF-βligands involved in developmental regulation of fiber size.
Mitochondrial Translation and Beyond: Processes Implicated in Combined Oxidative Phosphorylation Deficiencies
Authors: Smits Paulien , Smeitink Jan , van den Heuvel Lambert
Published: April 2010

Mitochondrial disorders are a heterogeneous group of often multisystemic and early fatal diseases, which are amongst the most common inherited human diseases. These disorders are caused by defects in the oxidative phosphorylation (OXPHOS) system, which comprises five multisubunit enzyme complexes encoded by both the nuclear and the mitochondrial genomes. Due to the multitude of proteins and intricacy of the processes required for a properly functioning OXPHOS system, identifying the genetic defect that underlies an OXPHOS deficiency is not an easy task, especially in the case of combined OXPHOS defects. In the present communication we give an extensive overview of the proteins and processes (in)directly involved in mitochondrial translation and the biogenesis of the OXPHOS system and their roles in combined OXPHOS deficiencies. This knowledge is important for further research into the genetic causes, with the ultimate goal to effectively prevent and cure these complex and often devastating disorders.
Adipose-Derived Mesenchymal Stem Cells as Stable Source of Tumor Necrosis Factor–Related Apoptosis-Inducing Ligand Delivery for Cancer Therapy
Authors: Grisendi Giulia , Bussolari Rita , Cafarelli Luigi , Petak Istvan , Rasini Valeria , Veronesi Elena , De Santis Giorgio , Spano Carlotta , Tagliazzucchi Mara , Barti-Juhasz Helga , Scarabelli Laura , Bambi Franco , Frassoldati Antonio , Rossi Giulio , Casali Christian , Morandi Uliano , Horwitz Edwin M. , Paolucci Paolo , Conte PierFranco , Dominici Massimo
Published: April 2010

Adipose-derived mesenchymal stromal/stem cells (AD-MSC) may offer efficient tools for cell-based gene therapy approaches. In this study, we evaluated whether AD-MSC could deliver proapoptotic molecules for cancer treatment. Human AD-MSCs were isolated and transduced with a retroviral vector encoding full-length human tumor necrosis factor–related apoptosis-inducing ligand (TRAIL), a proapoptotic ligand that induces apoptosis in a variety of human cancers but not normal tissues. Although several studies have documented the antitumor activity of recombinant human TRAIL, its use in vivo is limited by a short half-life in plasma due to a rapid clearance by the kidney. We found that these limitations can be overcome using stably transduced AD-MSC, which could serve as a constant source of TRAIL production. AD-MSC armed with TRAIL targeted a variety of tumor cell lines in vitro, including human cervical carcinoma, pancreatic cancer, colon cancer, and, in combination with bortezomib, TRAIL-resistant breast cancer cells. Killing activity was associated with activation of caspase-8 as expected. When injected i.v. or s.c. into mice, AD-MSC armed with TRAIL localized into tumors and mediated apoptosis without significant apparent toxicities to normal tissues. Collectively, our results provide preclinical support for a model of TRAIL-based cancer therapy relying on the use of adipose-derived mesenchymal progenitors as cellular vectors. Cancer Res; 70(9); 3718–29. ©2010 AACR.
Activation of Endothelial Ras Signaling Bypasses Senescence and Causes Abnormal Vascular Morphogenesis
Authors: Bajaj Anshika , Zheng Qingxia , Adam Alejandro , Vincent Peter , Pumiglia Kevin
Published: April 2010

Angiogenesis is crucial for embryogenesis, reproduction, and wound healing and is a critical determinant of tumor growth and metastasis. The multifunctional signal transducer Ras is a proto-oncogene and frequently becomes mutated in a variety of human cancers, including angiosarcomas. Regulation of Ras is important for endothelial cell function and angiogenesis. Hyperactivation of Ras is linked with oncogene-induced senescence in many cell types. Given links between vascular malformations and angiosarcoma with activated Ras signaling, we sought to determine the consequence of sustained Ras activation on endothelial cell function. We find that sustained Ras activation in primary endothelial cells leads to prolonged activation of progrowth signaling, accompanied by a senescence bypass, enhanced proliferation, autonomous growth, and increased survival. Moreover, Ras severely compromises the ability of these cells to organize into vascular structures, instead promoting formation of planar endothelial sheets. This abnormal phenotype is regulated by phosphoinositide 3-kinase signaling, highlighting the therapeutic potential of agents targeting this axis in dealing with vascular morphogenic disorders and vascular normalization of tumors. Cancer Res; 70(9); 3803–12. ©2010 AACR.
Xg Expression in Ewing's Sarcoma Is of Prognostic Value and Contributes to Tumor Invasiveness
Authors: Meynet Ophélie , Scotlandi Katia , Pradelli Emmanuelle , Manara Maria C. , Colombo Mario P. , Schmid-Antomarchi Heidy , Picci Piero , Bernard Alain , Bernard Ghislaine
Published: April 2010

Ewing's sarcoma (EWS) is an aggressive tumor of children and young adults that requires intensive treatment. The search for new prognostic factors is very important to choose the most appropriate therapy and to better understand the biology of the disease for the development of new therapeutic tools. We found that Xg, a thus far poorly described molecule and member of the CD99 family, is expressed in EWS cell lines and EWS primary tumors. Immunohistochemical analysis confirmed the expression of Xg in 24% of patients. We found that Xg expression in EWS defines a subgroup of patients with worse prognosis compared with those with Xg-negative localized tumors, indicating a clinical relevance of Xg expression in EWS. Forced expression of Xg in an EWS cell line upregulated cell migration and invasion in vitro. Furthermore, knockdown of Xg expression with specific short hairpin RNA significantly reduced migration and invasion of EWS cells. Consistent with these data, in vivo xenotransplant studies in nude mice revealed that Xg expression increased the incidence and the number of metastases of EWS cells. Thus, Xg expression is associated with lower overall survival in EWS patients with localized tumors and is implicated in metastasis. Cancer Res; 70(9); 3730–8. ©2010 AACR.
Signal Transducers and Activators of Transcription-3 Binding to the Fibroblast Growth Factor Receptor Is Activated by Receptor Amplification
Authors: Dudka Anna A. , Sweet Steve M.M. , Heath John K.
Published: April 2010

Fibroblast growth factor receptors (FGFR) are cell surface tyrosine kinases that function in cell proliferation and differentiation. Aberrant FGFR signaling occurs in diverse cancers due to gene amplification, but the associated oncogenic mechanisms are poorly understood. Using a proteomics approach, we identified signal transducers and activators of transcription-3 (STAT3) as a receptor-binding partner that is mediated by Tyr677 phosphorylation on FGFR. Binding to activated FGFR was essential for subsequent tyrosine phosphorylation and nuclear translocation of STAT3, along with activation of its downstream target genes. Tyrosine phosphorylation of STAT3 was also dependent on concomitant FGFR-dependent activity of SRC and JAK kinases. Lastly, tyrosine (but not serine) phosphorylation of STAT3 required amplified FGFR protein expression, generated either by enforced overexpression or as associated with gene amplification in cancer cells. Our findings show that amplified FGFR expression engages the STAT3 pathway, and they suggest therapeutic strategies to attack FGFR-overexpressing cancers. Cancer Res; 70(8); 3391–401. ©2010 AACR.
A Unique Pharmacophore for Activation of the Nuclear Orphan Receptor Nur77 In vivo and In vitro
Authors: Liu Jing-jing , Zeng Hui-ni , Zhang Lian-ru , Zhan Yan-yan , Chen Yan , Wang Yuan , Wang Juan , Xiang Shao-hua , Liu Wen-jun , Wang Wei-jia , Chen Hang-zi , Shen Yue-mao , Su Wen-jin , Huang Pei-qiang , Zhang Hong-kui , Wu Qiao
Published: April 2010

Nur77 is a steroid orphan receptor that plays a critical role in regulating proliferation, differentiation, and apoptosis, including acting as a switch for Bcl-2 function. We previously reported that the octaketide cytosporone B (Csn-B) is a natural agonist for Nur77. In this study, we synthesized a series of Csn-B analogues and performed a structure-activity analysis that suggested criteria for the development of a unique pharmacophore to activate Nur77. The components of the pharmacophore necessary for binding Nur77 included the benzene ring, the phenolic hydroxyl group, and the acyl chain of the Csn-B scaffold, whereas the key feature for activating the biological function of Nur77 was the ester group. Csn-B analogues that bound Nur77 tightly not only stimulated its transactivation activity but also initiated mitochondrial apoptosis by means of novel cross-talk between Nur77 and BRE, an antiapoptotic protein regulated at the transcriptional level. Notably, the derivative n-amyl 2-[3,5-dihydroxy-2-(1-nonanoyl)phenyl]acetate exhibited greater antitumor activity in vivo than its parent compounds, highlighting particular interest in this compound. Our findings describe a pathway for rational design of Csn-B–derived Nur77 agonists as a new class of potent and effective antitumor agents. Cancer Res; 70(9); 3628–37. ©2010 AACR.
ID1 Enhances Docetaxel Cytotoxicity in Prostate Cancer Cells through Inhibition of p21
Authors: Geng Hao , Rademacher Brooks L. , Pittsenbarger Janet , Huang Chung-Ying , Harvey Christopher T. , Lafortune Marie C. , Myrthue Anne , Garzotto Mark , Nelson Peter S. , Beer Tomasz M. , Qian David Z.
Published: April 2010

To identify potential mechanisms underlying prostate cancer chemotherapy response and resistance, we compared the gene expression profiles in high-risk human prostate cancer specimens before and after neoadjuvant chemotherapy and radical prostatectomy. Among the molecular signatures associated with chemotherapy, transcripts encoding inhibitor of DNA binding 1 (ID1) were significantly upregulated. The patient biochemical relapse status was monitored in a long-term follow-up. Patients with ID1 upregulation were found to be associated with longer relapse-free survival than patients without ID1 increase. This in vivo clinical association was mechanistically investigated. The chemotherapy-induced ID1 upregulation was recapitulated in the prostate cancer cell line LNCaP. Docetaxel dose-dependently induced ID1 transcription, which was mediated by ID1 promoter E-box chromatin modification and c-Myc binding. Stable ID1 overexpression in LNCaP increased cell proliferation, promoted G1 cell cycle progression, and enhanced docetaxel-induced cytotoxicity. These changes were accompanied by a decrease in cellular mitochondria content, an increase in BCL2 phosphorylation at serine 70, caspase-3 activation, and poly(ADP-ribose) polymerase cleavage. In contrast, ID1 siRNA in the LNCaP and C42B cell lines reduced cell proliferation and decreased docetaxel-induced cytotoxicity by inhibiting cell death. ID1-mediated chemosensitivity enhancement was in part due to ID1 suppression of p21. Overexpression of p21 in LNCaP-ID1–overexpressing cells restored the p21 level and reversed ID1-enhanced chemosensitivity. These molecular data provide a mechanistic rationale for the observed in vivo clinical association between ID1 upregulation and relapse-free survival. Taken together, it shows that ID1 expression has a novel therapeutic role in prostate cancer chemotherapy and prognosis. Cancer Res; 70(8); 3239–48. ©2010 AACR.
YPEL3, a p53-Regulated Gene that Induces Cellular Senescence
Authors: Kelley Kevin D. , Miller Kelly R. , Todd Amber , Kelley Amy R. , Tuttle Rebecca , Berberich Steven J.
Published: April 2010

Cellular senescence, the limited ability of cultured normal cells to divide, can result from cellular damage triggered through oncogene activation (premature senescence) or the loss of telomeres following successive rounds of DNA replication (replicative senescence). Although both processes require a functional p53 signaling pathway, relevant downstream p53 targets have been difficult to identify. Discovery of senescence activators is important because induction of tumor cell senescence may represent a therapeutic approach for the treatment of cancer. In microarray studies in which p53 was reactivated in MCF7 cells, we discovered that Yippee-like-3 (YPEL3), a member of a recently discovered family of putative zinc finger motif coding genes consisting of YPEL1-5, is a p53-regulated gene. YPEL3 expression induced by DNA damage leads to p53 recruitment to a cis-acting DNA response element located near the human YPEL3 promoter. Physiologic induction of YPEL3 results in a substantial decrease in cell viability associated with an increase in cellular senescence. Through the use of RNAi and H-ras induction of cellular senescence, we show that YPEL3 activates cellular senescence downstream of p53. Consistent with its growth suppressive activity, YPEL3 gene expression is repressed in ovarian tumor samples. One mechanism of YPEL3 downregulation in ovarian tumor cell lines seems to be hypermethylation of a CpG island upstream of the YPEL3 promoter. We believe these findings point to YPEL3 being a novel tumor suppressor, which upon induction triggers a permanent growth arrest in human tumor and normal cells. Cancer Res; 70(9); 3566–75. ©2010 AACR.
miR-212 Increases Tumor Necrosis Factor–Related Apoptosis-Inducing Ligand Sensitivity in Non–Small Cell Lung Cancer by Targeting the Antiapoptotic Protein PED
Authors: Incoronato Mariarosaria , Garofalo Michela , Urso Loredana , Romano Giulia , Quintavalle Cristina , Zanca Ciro , Iaboni Margherita , Nuovo Gerald , Croce Carlo Maria , Condorelli Gerolama
Published: April 2010

PED/PEA-15 (PED) is a death effector domain family member of 15 kDa with a broad antiapoptotic function found overexpressed in a number of different human tumors, including lung cancer. To date, the mechanisms that regulate PED expression are unknown. Therefore, we address this point by the identification of microRNAs that in non–small cell lung cancer (NSCLC) modulate PED levels. In this work, we identify miR-212 as a negative regulator of PED expression. We also show that ectopic expression of this miR increases tumor necrosis factor–related apoptosis-inducing ligand (TRAIL)–induced cell death in NSCLC cells. In contrast, inhibition of endogenous miR-212 by use of antago-miR results in increase of PED protein expression and resistance to TRAIL treatment. Besides, in NSCLC, we show both in vitro and in vivo that PED and miR-212 expressions are inversely correlated, that is, PED is upregulated and miR-212 is rarely expressed. In conclusion, these findings suggest that miR-212 should be considered as a tumor suppressor because it negatively regulates the antiapoptotic protein PED and regulates TRAIL sensitivity. Cancer Res; 70(9); 3638–46. ©2010 AACR.
Downregulation of HtrA1 Promotes Resistance to Anoikis and Peritoneal Dissemination of Ovarian Cancer Cells
Authors: He Xiaoping , Ota Takayo , Liu Peng , Su Changqing , Chien Jeremy , Shridhar Viji
Published: April 2010

We previously identified serine protease HtrA1 as a downregulated gene in epithelial ovarian cancer (EOC), but the functional consequence of loss of HtrA1 in EOC remains largely unclear. Here, we report that loss of HtrA1 attenuates anoikis—a critical physiologic barrier for tumor metastasis. In response to loss of anchorage, HtrA1 expression was upregulated in SKOV3 cells, resulting in autocatalytic activation of HtrA1. Stable knockdown of HtrA1 in SKOV3 and TOV21G cells resulted in resistance to anoikis due to enhanced activation of epidermal growth factor receptor (EGFR)/AKT pathway. In suspended SKOV3 cells, enhanced expression of HtrA1 inhibited EGFR/AKT pathway, leading to increased cell death, whereas protease-inactive mutant HtrA1 failed to result in either the inhibition of EGFR/AKT pathway or increased cell death, suggesting the requirement of HtrA1 protease activity in regulating anoikis. Immunoprecipitation and immunofluorescence assays revealed that HtrA1 interacted with EGFR not only on the cell membrane but also in the nucleus. Most importantly, downregulation of HtrA1 significantly enhanced the peritoneal dissemination of SKOV3ip1 cells in nonobese diabetic/severe combined immunodeficient mice, with increased phospho-EGFR level in corresponding tumor nodules compared with that in xenografts originated from the control cells. Taken together, these data reveal for the first time a novel function of HtrA1 in promoting anoikis by attenuating activation of EGFR/AKT pathway that may contribute to its metastasis suppression capacity, thus providing a possible explanation for the aggressive nature of human ovarian tumors with downregulated HtrA1. Cancer Res; 70(8); 3109–18. ©2010 AACR.
The Chemokine Receptor CXCR7 Is Highly Expressed in Human Glioma Cells and Mediates Antiapoptotic Effects
Authors: Hattermann Kirsten , Held-Feindt Janka , Lucius Ralph , Müerköster Susanne Sebens , Penfold Mark E.T. , Schall Thomas J. , Mentlein Rolf
Published: April 2010

The chemokine CXCL12/stromal cell–derived factor-1 and its receptor CXCR4 play a major role in tumor invasion, proliferation, and metastasis. Recently, CXCR7 was identified as a novel, alternate receptor for CXCL12 and CXCL11/I-TAC. Because both chemokines are expressed abundantly in human astrocytomas and glioblastomas, we investigated the occurrence and function of both receptors in astroglial tumors. In situ, CXCR7 is highly expressed on tumor endothelial, microglial, and glioma cells whereas CXCR4 has a much more restricted localization; CXCL12 is often colocalized with CXCR7. CXCR7 transcription in tumor homogenates increased with malignancy. In vitro, CXCR7 was highly expressed in all glioma cell lines investigated whereas CXCR4 was only scarcely transcribed on one of eight lines. In contrast, a tumor stem-like cell line preferentially expressed CXCR4 which diminished upon differentiation, whereas CXCR7 increased drastically. Stimulation of CXCR7-positive glioma cells (CXCR4- and CXCR3-negative) by CXCL12 induced transient phosphorylation of extracellular signal-regulated kinases Erk1/2, indicating that the receptor is functionally active. The phosphoinositide-specific phospholipase C inhibitor U73122 effectively inhibited Erk activation and suggests that the mitogen-activated protein kinase pathway is activated indirectly. Whereas proliferation and migration were little influenced, chemokine stimulation prevented camptothecin- and temozolomide-induced apoptosis. The selective CXCR7 antagonist CCX733 reduced the antiapoptotic effects of CXCL12 as shown by nuclear (Nicoletti) staining, caspase-3/7 activity assays, and cleavage of poly(ADP-ribose) polymerase-1. Thus, CXCR7 is a functional receptor for CXCL12 in astrocytomas/glioblastomas and mediates resistance to drug-induced apoptosis. Whereas CXCR7 is found on “differentiated” glioma cells, the alternate receptor CXCR4 is also localized on glioma stem-like cells. Cancer Res; 70(8); 3299–308. ©2010 AACR.
Aberrant Activation of the Androgen Receptor by NF-κB2/p52 in Prostate Cancer Cells
Authors: Nadiminty Nagalakshmi , Lou Wei , Sun Meng , Chen Jun , Yue Jiao , Kung Hsing-Jien , Evans Christopher P. , Zhou Qinghua , Gao Allen C.
Published: April 2010

Prostate cancer initiation and progression are uniquely dependent on the androgen receptor (AR). Even when the cancer progresses to a castration-resistant stage, AR signaling remains active via a variety of mechanisms. In the present study, we showed that NF-κB/p52 can activate the AR, resulting in increased transactivation of AR-responsive genes, such as PSA and NKX3.1, in a ligand-independent manner. NF-κB2/p52 enhances nuclear translocation and activation of AR by interacting with its NH2-terminal domain and enhances the recruitment of coactivators such as p300 to the promoters of AR-dependent genes. These results were confirmed in three different prostate cancer cell lines: LAPC-4 (wild-type AR), LNCaP (mutant AR), and C4-2 (castration resistant). Transfection of p52 into LAPC-4 and LNCaP cells (which express low levels of p52) showed increased activation of the endogenous AR. Downregulation of endogenous p52 in C4-2 cells resulted in abrogation of AR constitutive activation. Comparison of the relative effects of p52 and p65 (RelA) showed that p52, but not p65, could activate the AR. Collectively, these findings, together with previous reports that the levels of NF-κB2/p52 are elevated in prostate cancer cells and that active NF-κB2/p52 promotes prostate cancer cell growth in vitro and in vivo, suggest that NF-κB2/p52 may play a critical role in the progression of castration-resistant prostate cancer. Cancer Res; 70(8); 3309–19. ©2010 AACR.