bluuebunny/crossref_metadata_2025 huggingface dataset:
Contrasting Population Dynamics of the Endemic New Caledonian ConiferAraucaria laubenfelsiiin Maquis and Rain Forest
Authors: Rigg Lesley S. , Enright Neal J. , Jaffré Tanguy , Perry George L. W.
Published: January 2010

This study compares demographic parameters and population dynamics for high disturbance (maquis) and low disturbance (rain forest) environments of the montane conifer,Araucaria laubenfelsii, in New Caledonia. The establishment, growth, survival and reproduction ofca2500 individuals were followed in permanent plots over 10 yr. Growth and survival rates forA. laubenfelsiishow that it is a long‐lived, slow growing tree, with evidence of suppression in the sapling size classes in mature rain forest. Growth rates for all size classes are generally faster in maquis than rain forest. Transition matrix analyses estimated positive rates of population increase (λvalues>1), with populations expanding in maquis, and stable in mature forest.Araucaria laubenfelsiiis able to regenerate continuously in maquis and early successional rain forest, but recruitment is limited in older stands. Life table response experiment analyses showed that reproduction, and transitions from sapling to mature tree stage, contributed positively toλin maquis, but negatively in forest.Araucaria laubenfelsiion Mont Do can be considered a long‐lived pioneer, with early maquis colonizers helping to drive succession from maquis to forest. While opportunities for recruitment decline with time as rain forest sites develop a closed canopy, occasional gap phase recruitment, combined with disturbance by cyclones, landslides and fire, provide opportunities to ensure species persistence. Understanding contrasting population dynamics ofA. laubenfelsiiin maquis and rain forest will better facilitate conservation management of this species, particularly given current high rates of land conversion and degradation in New Caledonia.

Abstract in French is available athttp://www.blackwell‐synergy.com/loi/btp
Macronutrient Regulation in the Tropical Terrestrial Ant Ectatomma ruidum (Formicidae): A Field Study in Costa Rica
Authors: Cook Steven C. , Behmer Spencer T.
Published: January 2010

Using the geometric framework for the first time in a field study of ant nutritional biology, we show that Ectatomma ruidum colonies actively regulate protein–carbohydrate intake, self‐selecting a carbohydrate‐biased diet. These data, combined with quantitative recruitment data, provide a more comprehensive understanding of colony‐level nutritional requirements of ants.

Abstract in Spanish is available at http://www.blackwell‐synergy.com/loi/btp
Higher Soluble Amyloid β Concentration in Frontal Cortex of Young Adults than in Normal Elderly or Alzheimer's Disease
Authors: Van Helmond Zoë , Miners J. Scott , Kehoe Patrick G. , Love Seth
Published: January 2010

Little is known about the relationship between soluble amyloid β (Aβ) and age. We have measured soluble and insoluble Aβ by enzyme‐linked immunosorbent assay (ELISA) in post‐mortem frontal cortex in normal brains (16–95 years) and AD. Insoluble Aβ increased with age, and was significantly higher in Alzheimer's disease (AD) than age‐matched controls. However, levels of soluble Aβ declined with age and were significantly greater in younger adults than older adults with or without AD. In AD, insoluble : soluble Aβ ratio was much higher than in age‐matched controls. The high levels of soluble Aβ in young adults included oligomeric species of Aβ1‐42. These observations do not preclude Aβ oligomers as neurotoxic mediators of AD but suggest that if they are, the toxicity may be restricted to certain species (eg, β‐pleated protofibrillar species not detected by our assay) or takes decades to manifest. The dramatically increased insoluble : soluble Aβ in AD points to an altered dynamic equilibrium of Aβ in AD, reflecting both enhanced aggregation and continued overproduction or impaired removal of the soluble peptide in older age, when the concentration of this peptide should be declining.
Glioma Pathophysiology: Insights Emerging from Proteomics
Authors: Deighton Ruth F. , McGregor Richard , Kemp Jocelyn , McCulloch James , Whittle Ian R.
Published: January 2010

Proteomics is increasingly employed in both neurological and oncological research to provide insight into the molecular basis of disease but rarely has a coherent, novel pathophysiological insight emerged. Gliomas account for >50% of adult primary intracranial tumors, with malignant gliomas (anaplastic astrocytomas and glioblastoma multiforme) being the most common. In glioma, the application of proteomic technology has identified altered protein expression but without consistency of these alterations or their biological significance being established. A systematic review of multiple independent proteomic analyses of glioma has demonstrated alterations of 99 different proteins. Importantly 10 of the 99 proteins found differentially expressed in glioma [PHB, Hsp20, serum albumin, epidermal growth factor receptor (EGFR), EA‐15, RhoGDI, APOA1, GFAP, HSP70, PDIA3] were identified in multiple publications. An assessment of protein–protein interactions between these proteins compiled using novel web‐based technology, revealed a robust and cohesive network for glioblastoma. The protein network discovered (containing TP53 and RB1 at its core) compliments recent findings in genomic studies of malignant glioma. The novel perspective provided by network analysis indicates that the potential of this technology to explore crucial aspects of glioma pathophysiology can now be realized but only if the conceptual and technical limitations highlighted in this review are addressed.
Chiral bis‐Acetal Porphyrazines as Near‐infrared Optical Agents for Detection and Treatment of Cancer
Authors: Trivedi Evan R. , Vesper Benjamin J. , Weitman Hana , Ehrenberg Benjamin , Barrett Anthony G.M. , Radosevich James A. , Hoffman Brian M.
Published: January 2010

We report the preparation of chiral oxygen atom‐appended porphyrazines (pzs) as biomedical optical agents that absorb and emit in the near‐IR wavelength range. These pzs take the form M[pz(A4‐nBn)], where “A” and “B” represent moieties appended to the pz’s pyrrole entities, A = (2R,3R) 2,3‐dimethyl‐2,3‐dimethoxy‐1,4‐diox‐2‐ene, B = β,β′‐di‐isopropoxybenzo, M is the incorporated metal ion (M = H2, Zn), and n = 0, 1, 2 (‐cis/‐trans) and 3 (Scheme 1). When dissolved in polar media, H2[pz(trans‐A2B2)] 5a does not fluoresce and has a negligible quantum yield for singlet oxygen generation (ФΔ = 0.074 ± 0.001, methanol), as measured by the photo‐oxidation of DMA. However, when sequestered in the nonpolar environment of a liposome, it displays strong NIR emission (λmax = 705 nm, Фf = 0.087) and an extremely high singlet oxygen quantum yield (ФΔ→1). Of this series, H2[pz(trans‐A2B2)] 5a is attractive as a potential optical probe, showing strongly fluorescent uptake by cells in culture, while 3‐[4,5‐dimethylthiazol‐2‐yl]‐2,5‐diphenyltetrazolium bromide measurements of cell viability show no evidence of dark toxicity. This agent does show significant photoinduced toxicity suggesting that pzs such as 5a have promise as “theranostic” optical agents that can be visualized with fluorescence imaging while acting as a sensitizer for photodynamic therapy.

 Synthesis of Porphyrazines 3a–7a, 3b–7b.

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Roller-reversal imprint process for preparation of large-area microstructures
Authors: Liu Hongzhong , Jiang Weitao , Ding Yucheng , Shi Yongsheng , Yin Lei
Published: January 2010

The preparation of microstructures with certain patterns on a large-area substrate, especially on a flexible substrate, is a critical step in the development or production of flexible electronics (or macroelectronics). In this article, a novel roller-reversal imprint (RRI) process for the generation of large-area microstructures is proposed. In contrast to other published roller-imprint processes (such as hot embossing and ultraviolet roller-imprint), in which the material to be patterned is firstly film coated on the substrate and then the mold roller is pressed to the film, the RRI process starts with coating of the ink (mostly various liquefied electronics materials, such as a semiconductor polymer) on a patterned mold roller and then transferring the patterned ink to the substrate. The RRI process can be used to prepare micropatterns of various ink materials on a flexible substrate. By properly controlling the ink filling the microcavities on the mold roller and ink transfer to the substrate, the RRI process can achieve a pattern transfer without forming an undesirable residual layer, which is typical in other imprint processes. Furthermore, an experimental device for the RRI process is also developed for ink transfer to a flat, flexible substrate. A four-step alignment approach for the preparation of multilayer microstructures (as required in active macroelectronics) is proposed for the RRI, achieving an alignment accuracy of 0.2μm and an overlay error of about 5μm.
Intermittent Prophylaxis with Oral Truvada Protects Macaques from Rectal SHIV Infection
Authors: García-Lerma J. Gerardo , Cong Mian-er , Mitchell James , Youngpairoj Ae S. , Zheng Qi , Masciotra Silvina , Martin Amy , Kuklenyik Zsuzsanna , Holder Angela , Lipscomb Jonathan , Pau Chou-Pong , Barr John R. , Hanson Debra L. , Otten Ron , Paxton Lynn , Folks Thomas M. , Heneine Walid
Published: January 2010

Treating monkeys with single doses of an antiretroviral drug before and after exposure to SHIV provides protection against infection, a schedule that may prove practical in humans.
Mechanism of a Metabolic Shift in Monkeys
Authors: Bremer Andrew A.
Published: January 2010

A new study investigates the mechanistic effects of fetal glucocorticoid exposure on metabolic syndrome in primates.
Decoding Renal Cell Carcinoma
Authors: Damani Samir
Published: January 2010

Deep sequencing unveils unchartered links to the etiology of kidney cancer.
EFFECT OF BOTH Z AND Z′ MEDIATED FLAVOR-CHANGING NEUTRAL CURRENTS ON THE BARYONIC RARE DECAY Λb→Λℓ+ℓ-
Authors: SAHOO S. , DAS C. K. , MAHARANA L.
Published: January 2010

We study the effect of both Z and Z′ mediated flavor-changing neutral currents (FCNCs) on the Λb→Λℓ+ℓ-(ℓ = μ, τ) rare decay. We find the branching ratio is reasonably enhanced from its Standard Model value due to the effect of both Z and Z′ mediated FCNCs, and gives the possibility of new physics beyond the Standard Model. The contribution of Z′ boson depends upon the precise value of MZ′.
ELECTROCHEMICAL PROPERTIES OF BiFeO3 THIN FILMS PREPARED BY PULSED LASER DEPOSITION
Authors: XIA HUI , YAN FENG , LAI MAN ON , LU LI , SONG WENDONG
Published: January 2010

BiFeO3 thin film is deposited on the stainless steel substrate by pulsed laser deposition (PLD). Structural characterization using X-ray diffraction indicates that the film is polycrystalline with perovskite structure. Morphology characterization by field emission scanning electron microscopy reveals that the film is composed of grains with wide size distribution with a porous structure. Charge/discharge in the potential range between 0.05 and 3 V shows that the reversible capacity of the first charge/discharge cycle at 280 mA/g current density is about 770 mAh/g with high columbic efficiency about 74%. The reversible capacity after 50 cycles remains 50% of its initial capacity. The preliminary results indicated that BiFeO3 is a promising high capacity anode for lithium-ion batteries.
THE STRUCTURAL PHASE AND MICROSTRUCTURES OF PEROVSKITE Ba(Ti1-xZrx)O3 CERAMICS USING THE COMBUSTION ROUTE
Authors: PHUNGJITT NALINEE , PANYA PERAPONG , BONGKARN THEERACHAI , VITTAYAKORN NARATIP
Published: January 2010

Ba ( Ti 1-x Zr x) O 3; BTZ (x = 0.20 and 0.25) ceramics are attractive candidates for dynamic random access memories, tunable microwave devices and capacitors. In this study, the preparation of BTZ powders and ceramics fabricated by the combustion method were studied in detail. The calcination and sintering conditions were performed from 600 to 900°C for 4 h and from 1300 to 1450°C for 2 h, respectively. The highest percentage of the cubic perovskite phase was found in the powders that were calcined at 800°C. A pure cubic perovskite structure was found in all ceramic samples. The average grain size increased with increasing sintering temperatures. Dielectric constant-temperature plots showed a maximum peak value of 7500 and 8300 for x = 0.20 and 0.25. The phase transition temperature of the BTZ ceramics occurred at 30°C and 10°C for x = 20 and 25, respectively.
PREPARATION OF CdIn2Se4n-TYPE SEMICONDUCTOR USED AS THERMOELECTRIC MATERIAL BY SOL–GEL METHOD
Authors: RUANTHON AUN-ANONG , SARAKONSRI THAPANEE , THANACHAYANONT CHANCHANA
Published: January 2010

The objective of this research was to study the effect of various parameters such as temperature and pH to the formation of cadmium indium selenide ( CdIn2 Se 4 ) thin films, which were fabricated by sol–gel dip-coating method. This n-type semiconductor compound is suitable for application as thermoelectric materials. Cadmium, indium, selenium precursors were separately dissolved by solvents: ethanol, hydrochloric acid, and acetic acid to form metal alkoxides. The precursor solutions were then mixed together in N 2 atmosphere. These metal alkoxides were hydrolyzed by adding water and then polycondensed by adding ethylene glycol to become gels. These gels were adjusted to various acid-base values by adding diethylnolamine. Glass substrates were dipped into the gels to form thin films. These thin films were annealed at various temperatures in N 2 atmosphere and characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and fourier transfrom infrared spectroscopy (FTIR) techniques. The results indicated that CdIn2 Se 4 compound occurred by the reaction at room temperature with pH 4 and annealed at 450°C in N 2 atmosphere.
Plasma Spraying and Characterization of Tungsten Carbide‐Cobalt Coatings by the Water‐Stabilized System WSP
Authors: Ctibor Pavel , Kašparová Micheala , Bellin Jeremy , Le Guen Emmanuel , Zahálka František
Published: January 2010

Tungsten carbide‐cobalt powders (WC‐17wt% Co) were plasma sprayed by a water‐stabilized system WSP. Experiments with variable feeding distances and spray distances were carried out. Thinner coatings were deposited on carbon steel substrates and thicker coatings on stainless steel substrates to compare different cooling conditions. Basic characterization of coatings was done by XRD, SEM, and light microscopy plus image analysis. Microhardness was measured on polished cross‐sections. The main focus of investigation was resistance against wear in dry as well as wet conditions. The appropriate tests were performed with set‐ups based on ASTM G65 and G75, respectively. The influence of spray parameters onto coating wear performance was observed. The results of mechanical tests were discussed in connection with changes of phase composition and with the quality of the coating′s microstructure. The results show that for obtaining the best possible WC‐17Co coating with WSP process, from the viewpoint of wear resistance, the desired parameters combination is long feeding distance combined with short spray distance.
Some Initial Conditions for Disposed Satellites of the Systems GPS and Galileo Constellations
Authors: Merguizo Sanchez Diogo , Yokoyama Tadashi , Brasil Pedro Ivo de Oliveira , Cordeiro Ricardo Reis
Published: January 2010

Through the averaged equations we revisit theoretical and numerical aspects of the
strong resonance that increases the eccentricity of the disposed objects of GPS and
Galileo Systems. A simple view of the phase space of the problem shows that the
resonance does not depend on the semi‐major axis. Therefore, usual strategies of
changing altitude (raising perigee) do not work. In this problem we search for a set of
initial conditions such that the deactivated satellites or upper‐stages remain at least for
250 years without penetrating in the orbits of the operational satellites. In the case that Moon′s perturbation is not significant, we can identify, in the phase space, the regions
where eccentricity reaches maximum and minimum values so that possible risks of
collision can be avoided. This is done semi‐analytically through the averaged system of
the problem. Guided by this idea, we numerically found the (ω, Ω) values of the real
unaveraged problem. In particular, for the Galileo case, the theoretical results predicted
in the averaged system are in good agreement with numerical results. We also show that
initial inclination of the Moon plays an important role in the search of these conditions.
Canine Leishmaniasis in Brazil: Serological Follow-Up of a Dog Population in an Endemic Area of American Visceral Leishmaniasis
Authors: da Silva Alba Valéria Machado , de Paula Adelzon Assis , Pereira Daniela de Pita , Brazil Reginaldo Peçanha , Carreira João Carlos Araujo
Published: January 2010

We performed a serological, clinical, and parasitological follow-up of a dog population in an endemic area of American Visceral Leishmaniasis estimated by indirect immunofluorescent assay (IFA) and western blot (WB). After twelve months, the results obtained from IFA demonstrated that 50% were seropositive and two serological profiles were observed: the first one ranging from 1/40 to 1/80 and the second≥1/160. By WB, it was observed that the same percentage and sera from positive dogs presented the recognition of the peptides of 29 and 32 kDa up to 8 months before IFA serum conversion. Among the positive dogs, all the sera from symptomatic ones with tissue parasitism recognized the peptide of 68.5 kDa. Our results suggest the need of modifications in the control measures regarding the elimination of the dogs. They also corroborate the high sensitivity and specificity of western blot in the diagnosis of canine leishmaniasis, suggesting the possibility of its association with IFA.
Assessing the Open Trenches in Screening Railway Ground‐Borne Vibrations by Means of Artificial Neural Network
Authors: Di Mino Gaetano , Giunta Marinella , Di Liberto Ciro Maurizio
Published: January 2010

Reducing ground borne vibrations in urban areas is a very challenging task in railway transportation. Many mitigation measures can be considered and applied; among these open trenches are very effective.
This paper deals with the study of the effect, in terms of reduction of vertical and horizontal displacements and velocities, of the open trenches. 2D FEM simulations have been performed and several open trench configurations have been analysed varying the main geometric features such as width and depth, distance from the rail, thickness of the soil layer over the rigid bedrock, type of the ground, ratio between the depth of the trench, and the thickness of the soil layer. For quantifying the influence of the above specified parameters in reducing ground‐borne vibrations an analysis using artificial neural networks (ANNs) has been carried out. Results show that among the geometric parameters the role of the depth of the trench is very significant; however the influence of the depth must be also evaluated in relation to the thickness of the soil layer.
The SEMAINE API: Towards a Standards-Based Framework for Building Emotion-Oriented Systems
Authors: Schröder Marc
Published: January 2010

This paper presents the SEMAINE API, an open source framework for building emotion-oriented systems. By encouraging and simplifying the use of standard representation formats, the framework aims to contribute to interoperability and reuse of system components in the research community. By providing a Java and C++ wrapper around a message-oriented middleware, the API makes it easy to integrate components running on different operating systems and written in different programming languages. The SEMAINE system 1.0 is presented as an example of a full-scale system built on top of the SEMAINE API. Three small example systems are described in detail to illustrate how integration between existing and new components is realised with minimal effort.
Identification of the Receptor Tyrosine Kinase c-Met and Its Ligand, Hepatocyte Growth Factor, as Therapeutic Targets in Clear Cell Sarcoma
Authors: Davis Ian J. , McFadden Andrew W. , Zhang Yixiang , Coxon Angela , Burgess Teresa L. , Wagner Andrew J. , Fisher David E.
Published: January 2010

Clear cell sarcoma (CCS), a childhood tumor of the tendons and aponeuroses, is uniformly fatal once it has metastasized because of its profound therapeutic resistance. CCS is characterized by production of a chimeric transcription factor, EWS-ATF1, which is formed as the result of a disease-specific chromosomal translocation. EWS-ATF1 activates the melanocyte transcription factor MITF, which in turn activates transcription of c-Met, an oncogenic receptor tyrosine kinase recently shown to be activated in CCS. Based on this connection, we hypothesized that c-Met inhibition may offer a strategy to treat CCS, as an indirect tactic to defeat a transforming pathway downstream of EWS-ATF1. Here, we show that primary CCS and CCS-derived cell lines express c-Met, which is activated in an autocrine fashion by its ligand hepatocyte growth factor (HGF)/scatter factor in some CCS cell lines. c-Met expression is critical for CCS invasion, chemotaxis, and survival. Blocking c-Met activity with a small-molecule inhibitor (SU11274) or a neutralizing antibody to its ligand HGF (AMG 102) significantly reduced CCS cell growth in culture. Similarly, AMG 102 significantly suppressed in vivo tumor growth in an autocrine xenograft model of CCS. Collectively, these findings suggest the HGF:c-Met signaling axis as a candidate therapeutic target to improve clinical management of CCS. Cancer Res; 70(2); 639–45
The High Mobility Group A1 Gene: Transforming Inflammatory Signals into Cancer?
Authors: Resar Linda M.S.
Published: January 2010

High mobility group A1 (HMGA1) is highly expressed during embryogenesis and in poorly differentiated cancers, and high levels portend a poor prognosis in some tumors. HMGA1 induces oncogenic transformation in cultured cells and causes aggressive cancers in transgenic mice, whereas blocking it interferes with transformation in experimental models. These findings suggest a pivotal role for HMGA1 in cancer. This review focuses on two recently described HMGA1 transcriptional targets that mediate inflammatory signals and drive malignant transformation because they could serve as biomarkers or therapeutic targets. Further elucidation of HMGA1 function in transformation promises to have a major impact on our war on cancer. Cancer Res; 70(2); 436–9
Sym004: A Novel Synergistic Anti–Epidermal Growth Factor Receptor Antibody Mixture with Superior Anticancer Efficacy
Authors: Pedersen Mikkel Wandahl , Jacobsen Helle Jane , Koefoed Klaus , Hey Adam , Pyke Charles , Haurum John Sørensen , Kragh Michael
Published: January 2010

Epidermal growth factor receptor (EGFR) is a validated therapeutic target in cancer and EGFR antagonists with greater effectiveness than existing clinical agents remain of interest. Here, we report a novel approach based on Sym004, a mixture of two anti-EGFR monoclonal antibodies directed against distinct nonoverlapping epitopes in EGFR extracellular domain III. Like anti-EGFR monoclonal antibodies in current clinical use, Sym004 inhibits cancer cell growth and survival by blocking ligand-binding receptor activation and phosphorylation and downstream receptor signaling. However, unlike the other antibodies, Sym004 induces rapid and efficient removal of the receptor from the cancer cell surface by triggering EGFR internalization and degradation. Compared with reference anti-EGFR monoclonal antibodies, Sym004 exhibited more pronounced growth inhibition in vitro and superior efficacy in vivo. Together, these findings illustrate a strategy to target EGFR more effectively than existing clinical antibodies. Cancer Res; 70(2); 588–97
Transcriptional Autoregulation by BRCA1
Authors: De Siervi Adriana , De Luca Paola , Byun Jung S. , Di Li Jun , Fufa Temesgen , Haggerty Cynthia M. , Vazquez Elba , Moiola Cristian , Longo Dan L. , Gardner Kevin
Published: January 2010

The BRCA1 gene product plays numerous roles in regulating genome integrity. Its role in assembling supermolecular complexes in response to DNA damage has been extensively studied; however, much less is understood about its role as a transcriptional coregulator. Loss or mutation is associated with hereditary breast and ovarian cancers, whereas altered expression occurs frequently in sporadic forms of breast cancer, suggesting that the control of BRCA1 transcription might be important to tumorigenesis. Here, we provide evidence of a striking linkage between the roles for BRCA1 as a transcriptional coregulator with control of its expression via an autoregulatory transcriptional loop. BRCA1 assembles with complexes containing E2F-1 and RB to form a repressive multicomponent transcriptional complex that inhibits BRCA1 promoter transcription. This complex is disrupted by genotoxic stress, resulting in the displacement of BRCA1 protein from the BRCA1 promoter and subsequent upregulation of BRCA1 transcription. Cells depleted of BRCA1 respond by upregulating BRCA1 transcripts, whereas cells overexpressing BRCA1 respond by downregulating BRCA1 transcripts. Tandem chromatin immmunoprecipitation studies show that BRCA1 is regulated by a dynamic coregulatory complex containing BRCA1, E2F1, and Rb at the BRCA1 promoter that is disrupted by DNA-damaging agents to increase its transcription. These results define a novel transcriptional mechanism of autoregulated homeostasis of BRCA1 that selectively titrates its levels to maintain genome integrity in response to genotoxic insult. Cancer Res; 70(2); 532–42
Oncogenic B-RafV600E Induces Spindle Abnormalities, Supernumerary Centrosomes, and Aneuploidy in Human Melanocytic Cells
Authors: Cui Yongping , Borysova Meghan K. , Johnson Joseph O. , Guadagno Thomas M.
Published: January 2010

Activating B-Raf mutations arise in 60% to 70% of human melanomas and are thought to play a vital role in tumorigenesis, although how this occurs remains poorly understood. Wild-type B-Raf is critical for normal mitosis of human somatic cells, suggesting that mutational activation of B-Raf might compromise mitosis. We examined this hypothesis by introducing oncogenic mutant B-RafV600E into established human melanoma cells, assessing the effects on mitosis and their possible relationship to extracellular signal–regulated kinase (ERK) pathway activation. Exogenous expression of this activated B-Raf mutant led to a high incidence of aberrant spindles and supernumerary centrosomes. These mitotic abnormalities were suppressed by expression of a B-RafV600E mutant–specific shRNA or by the addition of the mitogen-activated protein/ERK kinase–specific inhibitor U0126. Mitotic abnormalities generated by B-RafV600E also caused missegregation of chromosomes leading to aneuploidy. Because activating B-Raf mutations are detected frequently in benign nevi, we extended our studies to primary human melanocytes. Remarkably, short-term expression of B-RafV600E was sufficient to induce aneuploidy in human melanocytes or in immortalized human mammary epithelial cells. Collectively, our studies identify a novel role for the B-Raf oncogene in driving aneuploidy in melanocytic cells. We propose that disruption of mitotic controls by oncogenic B-Raf has important implications for understanding melanoma tumor development. Cancer Res; 70(2); 675–84
Myxoma Virus Virotherapy for Glioma in Immunocompetent Animal Models: Optimizing Administration Routes and Synergy with Rapamycin
Authors: Lun XueQing , Alain Tommy , Zemp Franz J. , Zhou Hongyuan , Rahman Masmudur M. , Hamilton Mark G. , McFadden Grant , Bell John , Senger Donna L. , Forsyth Peter A.
Published: January 2010

Oncolytic myxoma virus (MYXV) is being developed as a novel virotherapeutic against human brain cancer and has promising activity against human brain tumor models in immunocompromised hosts. Because an intact immune system could reduce its efficacy, the purpose of this study was to evaluate the oncolytic potential of MYXV in immunocompetent racine glioma models. Here, we report that MYXV infects and kills all racine cell glioma lines and that its effects are enhanced by rapamycin. Intratumoral administration of MYXV with rapamycin improved viral replication in the tumor and significantly prolonged host survival. Similarly, coadministration via a method of convection-enhanced delivery (CED) enhanced viral replication and efficacy in vivo. Mechanisms by which rapamycin improved MYXV oncolysis included an inhibition of type I IFN production in vitro and a reduction of intratumoral infiltration of CD68+ microglia/macrophages and CD163+ macrophages in vivo. Our findings define a method to improve MYXV efficacy against gliomas by rapamycin coadministration, which acts to promote immune responses engaged by viral delivery. Cancer Res; 70(2); 598–608
Oncogenic BRAF Mutation with CDKN2A Inactivation Is Characteristic of a Subset of Pediatric Malignant Astrocytomas
Authors: Schiffman Joshua D. , Hodgson J. Graeme , VandenBerg Scott R. , Flaherty Patrick , Polley Mei-Yin C. , Yu Mamie , Fisher Paul G. , Rowitch David H. , Ford James M. , Berger Mitchel S. , Ji Hanlee , Gutmann David H. , James C. David
Published: January 2010

Malignant astrocytomas are a deadly solid tumor in children. Limited understanding of their underlying genetic basis has contributed to modest progress in developing more effective therapies. In an effort to identify such alterations, we performed a genome-wide search for DNA copy number aberrations (CNA) in a panel of 33 tumors encompassing grade 1 through grade 4 tumors. Genomic amplifications of 10-fold or greater were restricted to grade 3 and 4 astrocytomas and included the MDM4 (1q32), PDGFRA (4q12), MET (7q21), CMYC (8q24), PVT1 (8q24), WNT5B (12p13), and IGF1R (15q26) genes. Homozygous deletions of CDKN2A (9p21), PTEN (10q26), and TP53 (17p3.1) were evident among grade 2 to 4 tumors. BRAF gene rearrangements that were indicated in three tumors prompted the discovery of KIAA1549-BRAF fusion transcripts expressed in 10 of 10 grade 1 astrocytomas and in none of the grade 2 to 4 tumors. In contrast, an oncogenic missense BRAF mutation (BRAFV600E) was detected in 7 of 31 grade 2 to 4 tumors but in none of the grade 1 tumors. BRAFV600E mutation seems to define a subset of malignant astrocytomas in children, in which there is frequent concomitant homozygous deletion of CDKN2A (five of seven cases). Taken together, these findings highlight BRAF as a frequent mutation target in pediatric astrocytomas, with distinct types of BRAF alteration occurring in grade 1 versus grade 2 to 4 tumors. Cancer Res; 70(2); 512–9
Chemopreventive Agent 3,3′-Diindolylmethane Selectively Induces Proteasomal Degradation of Class I Histone Deacetylases
Authors: Li Yongming , Li Xia , Guo Bin
Published: January 2010

3,3′-Diindolylmethane (DIM) is an anticancer agent that induces cell cycle arrest and apoptosis through unknown mechanisms. Here, we report that DIM can selectively induce proteasome-mediated degradation of class I histone deacetylases (HDAC1, HDAC2, HDAC3, and HDAC8) without affecting the class II HDAC proteins. DIM induced downregulation of class I HDACs in human colon cancer cells in vitro and in vivo in tumor xenografts. HDAC depletion relieved HDAC-mediated transcriptional inhibition of the cyclin-dependent kinase inhibitors p21WAF1 and p27KIP2, significantly increasing their expression and triggering cell cycle arrest in the G2 phase of the cell cycle. Additionally, HDAC depletion was associated with an induction of DNA damage that triggered apoptosis. Our findings indicate that DIM acts to selectively target the degradation of class I HDACs. Cancer Res; 70(2); 646–54
Identification of USP18 as an Important Regulator of the Susceptibility to IFN-α and Drug-Induced Apoptosis
Authors: Potu Harish , Sgorbissa Andrea , Brancolini Claudio
Published: January 2010

Gene products that modify the apoptotic susceptibility of cancer cells may offer novel drug response markers or therapeutic targets. In this study, we probed the contribution of 53 different isopeptidases to apoptosis triggered by bortezomib and etoposide. USP18, a type I IFN-induced protein that deconjugates the ubiquitin-like modifier ISG15 from target proteins, was found to limit apoptotic susceptibility to IFN-α or bortezomib. Ablating USP18 in cells treated with IFN-α increased tumor necrosis factor–related apoptosis-inducing ligand (TRAIL) production; upregulated expression of transcription factors IFN-regulatory factor (IRF)-1, IRF-7, and IRF-9; and promoted the extrinsic pathway of apoptosis. The proapoptotic effects of ablating USP18 were abrogated by FLIP overexpression or TRAIL silencing. However, in bortezomib-treated cells, weak spontaneous signaling from type I IFNs was implicated in the proapoptotic effect of USP18 ablation. Ectopic USP18 repressed apoptotic signaling by IFN-α, TRAIL, or bortezomib. Similar effects were produced by a catalytically inactive USP18 mutant, indicating that the antiapoptotic function of USP18 is independent of its catalytic activity. These findings suggest that USP18 may significantly limit operation of the extrinsic apoptotic pathway triggered by type I IFN and drugs. Cancer Res; 70(2); 655–65
SLIT2 Attenuation during Lung Cancer Progression Deregulates β-Catenin and E-Cadherin and Associates with Poor Prognosis
Authors: Tseng Ruo-Chia , Lee Shih-Hua , Hsu Han-Shui , Chen Ben-Han , Tsai Wan-Ching , Tzao Ching , Wang Yi-Ching
Published: January 2010

Chromosome 4p15.3 is frequently deleted in late-stage lung cancer. We investigated the significance of the SLIT2 gene located in this region to lung cancer progression. SLIT2 encodes an extracellular glycoprotein that can suppress breast cancer by regulating β-catenin. In this study, we examined alterations in the structure or expression of SLIT2, its receptor ROBO1, and β-catenin, along with the AKT/glycogen synthase kinase 3β (GSK3β)/β-transducin repeat-containing protein (βTrCP) pathway in lung cancer cell lines and patients. Low SLIT2 expression correlated with an upward trend of pathological stage and poorer survival in lung cancer patients. Importantly, SLIT2, βTrCP, and β-catenin expression levels predicted postoperative recurrence of lung cancer in patients. Stimulating SLIT2 expression by various methods increased the level of E-cadherin caused by attenuation of its transcriptional repressor SNAI1. Conversely, knocking down SLIT2 expression increased cell migration and reduced cell adhesion through coordinated deregulation of β-catenin and E-cadherin/SNAI1 in the AKT/GSK3β/βTrCP pathway. Our findings indicate that SLIT2 suppresses lung cancer progression, defining it as a novel “theranostic” factor with potential as a therapeutic target and prognostic predictor in lung cancer. Cancer Res; 70(2); 543–51
Silencing of SPRY1 Triggers Complete Regression of Rhabdomyosarcoma Tumors Carrying a Mutated RAS Gene
Authors: Schaaf Gerben , Hamdi Mohamed , Zwijnenburg Danny , Lakeman Arjan , Geerts Dirk , Versteeg Rogier , Kool Marcel
Published: January 2010

RAS oncogenes are among the most frequently mutated genes in human cancer, but effective strategies for therapeutic inhibition of the RAS pathway have been elusive. Sprouty1 (SPRY1) is an upstream antagonist of RAS that is activated by extracellular signal-related kinase (ERK), providing a negative feedback loop for RAS signaling, and other evidence suggests that SPRY1 may have a tumor suppressor function. Studies of RAS status in the human childhood tumor rhabdomyosarcoma (RMS) indicated mutations in approximately half of the tumors of the embryonal rhabdomyosarcoma subtype (ERMS) but not the alveolar subtype (ARMS). ERMS tumors also showed overexpression of SPRY1, which was indeed upregulated by mutant RAS. However, we found that, in the presence of mutant RAS, the function of SPRY1 was changed from an antagonist to an agonist of RAS signaling. Thus, SPRY1 supported formation of activated ERK and mitogen-activated protein/ERK kinase and was essential for ERMS cell proliferation and survival. Conversely, silencing of SPRY1 in ERMS cells (but not ARMS cells) abolished their tumorigenicity in mice. Moreover, silencing of SPRY1 caused regression of established ERMS tumors (but not ARMS tumors) formed in xenograft settings. Our findings argue that SPRY1 inhibition can offer a therapeutic strategy to treat childhood RMS and possibly other tumors carrying oncogenic RAS mutations. Cancer Res; 70(2); 762–71
Estimating CDKN2A Carrier Probability and Personalizing Cancer Risk Assessments in Hereditary Melanoma Using MelaPRO
Authors: Wang Wenyi , Niendorf Kristin B. , Patel Devanshi , Blackford Amanda , Marroni Fabio , Sober Arthur J. , Parmigiani Giovanni , Tsao Hensin
Published: January 2010

Personalized cancer risk assessment remains an essential imperative in postgenomic cancer medicine. In hereditary melanoma, germline CDKN2A mutations have been reproducibly identified in melanoma-prone kindreds worldwide. However, genetic risk counseling for hereditary melanoma remains clinically challenging. To address this challenge, we developed and validated MelaPRO, an algorithm that provides germline CDKN2A mutation probabilities and melanoma risk to individuals from melanoma-prone families. MelaPRO builds on comprehensive genetic information, and uses Mendelian modeling to provide fine resolution and high accuracy. In an independent validation of 195 individuals from 167 families, MelaPRO exhibited good discrimination with a concordance index (C) of 0.86 [95% confidence intervals (95% CI), 0.75–0.97] and good calibration, with no significant difference between observed and predicted carriers (26; 95% CI, 20–35, as compared with 22 observed). In cross-validation, MelaPRO outperformed the existing predictive model MELPREDICT (C, 0.82; 95% CI, 0.61–0.93), with a difference of 0.05 (95% CI, 0.007–0.17). MelaPRO is a clinically accessible tool that can effectively provide personalized risk counseling for all members of hereditary melanoma families. Cancer Res; 70(2); 552–9
S1P2, the G Protein–Coupled Receptor for Sphingosine-1-Phosphate, Negatively Regulates Tumor Angiogenesis and Tumor Growth In vivo in Mice
Authors: Du Wa , Takuwa Noriko , Yoshioka Kazuaki , Okamoto Yasuo , Gonda Koichi , Sugihara Kazushi , Fukamizu Akiyoshi , Asano Masahide , Takuwa Yoh
Published: January 2010

Sphingosine-1-phosphate (S1P) has been implicated in tumor angiogenesis by acting through the Gi-coupled chemotactic receptor S1P1. Here, we report that the distinct receptor S1P2 is responsible for mediating the G12/13/Rho-dependent inhibitory effects of S1P on Akt, Rac, and cell migration, thereby negatively regulating tumor angiogenesis and tumor growth. By using S1P2LacZ/+ mice, we found that S1P2 was expressed in both tumor and normal blood vessels in many organs, in both endothelial cells (EC) and vascular smooth muscle cells, as well as in tumor-associated, CD11b-positive bone marrow–derived cells (BMDC). Lewis lung carcinoma or B16 melanoma cells implanted in S1P2-deficient (S1P2−/−) mice displayed accelerated tumor growth and angiogenesis with enhanced association of vascular smooth muscle cells and pericytes. S1P2−/− ECs exhibited enhanced Rac activity, Akt phosphorylation, cell migration, proliferation, and tube formation in vitro. Coinjection of S1P2−/− ECs and tumor cells into wild-type mice also produced a relative enhancement of tumor growth and angiogenesis in vivo. S1P2−/− mice were also more efficient at recruiting CD11b-positive BMDCs into tumors compared with wild-type siblings. Bone marrow chimera experiments revealed that S1P2 acted in BMDCs to promote tumor growth and angiogenesis. Our results indicate that, in contrast to endothelial S1P1, which stimulates tumor angiogenesis, S1P2 on ECs and BMDCs mediates a potent inhibition of tumor angiogenesis, suggesting a novel therapeutic tactic for anticancer treatment. Cancer Res; 70(2); 772–81
Insertional Mutagenesis in Mice Deficient for p15Ink4b, p16Ink4a, p21Cip1, and p27Kip1 Reveals Cancer Gene Interactions and Correlations with Tumor Phenotypes
Authors: Kool Jaap , Uren Anthony G. , Martins Carla P. , Sie Daoud , de Ridder Jeroen , Turner Geoffrey , van Uitert Miranda , Matentzoglu Konstantin , Lagcher Wendy , Krimpenfort Paul , Gadiot Jules , Pritchard Colin , Lenz Jack , Lund Anders H. , Jonkers Jos , Rogers Jane , Adams David J. , Wessels Lodewyk , Berns Anton , van Lohuizen Maarten
Published: January 2010

The cyclin dependent kinase (CDK) inhibitors p15, p16, p21, and p27 are frequently deleted, silenced, or downregulated in many malignancies. Inactivation of CDK inhibitors predisposes mice to tumor development, showing that these genes function as tumor suppressors. Here, we describe high-throughput murine leukemia virus insertional mutagenesis screens in mice that are deficient for one or two CDK inhibitors. We retrieved 9,117 retroviral insertions from 476 lymphomas to define hundreds of loci that are mutated more frequently than expected by chance. Many of these loci are skewed toward a specific genetic context of predisposing germline and somatic mutations. We also found associations between these loci with gender, age of tumor onset, and lymphocyte lineage (B or T cell). Comparison of retroviral insertion sites with single nucleotide polymorphisms associated with chronic lymphocytic leukemia revealed a significant overlap between the datasets. Together, our findings highlight the importance of genetic context within large-scale mutation detection studies, and they show a novel use for insertional mutagenesis data in prioritizing disease-associated genes that emerge from genome-wide association studies. Cancer Res; 70(2); 520–31
Genetic Analysis of Transforming Events That Convert Chronic Myeloproliferative Neoplasms to Leukemias
Authors: Abdel-Wahab Omar , Manshouri Taghi , Patel Jay , Harris Kelly , Yao JinJuan , Hedvat Cyrus , Heguy Adriana , Bueso-Ramos Carlos , Kantarjian Hagop , Levine Ross L. , Verstovsek Srdan
Published: January 2010

The oncogenetic events that transform chronic myeloproliferative neoplasms (MPN) to acute myeloid leukemias (AML) are not well characterized. We investigated the role of several genes implicated in leukemic transformation by mutational analysis of 63 patients with AML secondary to a preexisting MPN (sAML). Frequent mutations were identified in TET2 (26.3%), ASXL1 (19.3%), IDH1 (9.5%), and JAK2 (36.8%) mutations in sAML, and all possible mutational combinations of these genes were also observed. Analysis of 14 patients for which paired samples from MPN and sAML were available showed that TET2 mutations were frequently acquired at leukemic transformation [6 of 14 (43%)]. In contrast, ASXL1 mutations were almost always detected in both the MPN and AML clones from individual patients. One case was also observed where TET2 and ASXL1 mutations were found before the patient acquired a JAK2 mutation or developed clinical evidence of MPN. We conclude that mutations in TET2, ASXL1, and IDH1 are common in sAML derived from a preexisting MPN. Although TET2/ASXL1 mutations may precede acquisition of JAK2 mutations by the MPN clone, mutations in TET2, but not ASXL1, are commonly acquired at the time of leukemic transformation. Our findings argue that the mutational order of events in MPN and sAML varies in different patients, and that TET2 and ASXL1 mutations have distinct roles in MPN pathogenesis and leukemic transformation. Given the presence of sAML that have no preexisting JAK2/TET2/ASXL1/IDH1 mutations, our work indicates the existence of other mutations yet to be identified that are necessary for leukemic transformation. Cancer Res; 70(2); 447–52
Identification of Cyclooxygenase-2 as a Major Actor of the Transcriptomic Adaptation of Endothelial and Tumor Cells to Cyclic Hypoxia: Effect on Angiogenesis and Metastases
Authors: Daneau Géraldine , Boidot Romain , Martinive Philippe , Feron Olivier
Published: January 2010

Purpose: Cyclic hypoxia in tumors originates from heterogeneities in RBC flux and influences not only tumor cells but also endothelial cells lining tumor blood vessels. Whether pO2 fluctuations, particularly transient reoxygenation periods, alter the well-known hypoxia-inducible factor (HIF)–dependent gene program is largely unknown.

Experimental Design: We compared the transcriptomic profiles of endothelial and tumor cells exposed to cyclic hypoxia versus continuous hypoxia to uncover a possible differential effect on angiogenesis and metastases.

Results: Microarray analyses identified early genes that were selectively induced by cyclic hypoxia in endothelial cells. Among them, we focused on PTGS2 because the observed increase in mRNA expression led to a significant increase in the expression and activity of cyclooxygenase-2 (COX-2; the protein product of PTGS2). HIF-1α was shown to be stabilized by cyclic hypoxia (despite reoxygenation periods) and to favor COX-2 induction as validated by the use of echinomycin and HIF-1α targeting small interfering RNA. Using a specific COX-2 inhibitor and a dedicated COX-2 targeting small interfering RNA, we documented that COX-2 accounted for the higher endothelial cell survival and angiogenic potential conferred by cyclic hypoxia. Cyclic hypoxia also led to a preferential COX-2 induction in tumor cells and, contrary to continuous hypoxia, fostered a higher metastatic take of prechallenged tumor cells.

Conclusions: Our study documents that PTGS2/COX-2 is part of a cyclic hypoxia gene signature and largely accounts for the unique phenotype of endothelial and tumor cells exposed to fluctuations in pO2, thereby offering new perspectives for the clustering of tumors expressing COX-2 together with other cyclic hypoxia-responsive genes. Clin Cancer Res; 16(2); 410–9
New Insights into Checkpoint Kinase 1 in the DNA Damage Response Signaling Network
Authors: Dai Yun , Grant Steven
Published: January 2010

The DNA damage response (DDR) represents a complex network of multiple signaling pathways involving cell cycle checkpoints, DNA repair, transcriptional programs, and apoptosis, through which cells maintain genomic integrity following various endogenous (metabolic) or environmental stresses. In cancer treatment, the DDR occurs in response to various genotoxic insults by diverse cytotoxic agents and radiation, representing an important mechanism limiting chemotherapeutic and radiotherapeutic efficacy. This has prompted the development of agents targeting DDR signaling pathways, particularly checkpoint kinase 1 (Chk1), which contributes to all currently defined cell cycle checkpoints, including G1/S, intra-S-phase, G2/M, and the mitotic spindle checkpoint. Although numerous agents have been developed with the primary goal of enhancing the activity of DNA-damaging agents or radiation, the therapeutic outcome of this strategy remains to be determined. Recently, new insights into DDR signaling pathways support the notion that Chk1 represents a core component central to the entire DDR, including direct involvement in DNA repair and apoptotic events in addition to checkpoint regulation. Together, these new insights into the role of Chk1 in the DDR machinery could provide an opportunity for novel approaches to the development of Chk1 inhibitor strategies. Clin Cancer Res; 16(2); 376–83