bluuebunny/crossref_metadata_2025 huggingface dataset:
PDK-1/FoxO1 pathway in POMC neurons regulatesPomcexpression and food intake
Authors: Iskandar Kristy , Cao Yongheng , Hayashi Yoshitake , Nakata Masanori , Takano Eisuke , Yada Toshihiko , Zhang Changliang , Ogawa Wataru , Oki Miyo , Chua Streamson , Itoh Hiroshi , Noda Tetsuo , Kasuga Masato , Nakae Jun
Published: January 2010

Both insulin and leptin signaling converge on phosphatidylinositol 3-OH kinase [PI( 3 )K]/3-phosphoinositide-dependent protein kinase-1 (PDK-1)/protein kinase B (PKB, also known as Akt) in proopiomelanocortin (POMC) neurons. Forkhead box-containing protein-O1 (FoxO1) is inactivated in a PI( 3 )K-dependent manner. However, the interrelationship between PI( 3 )K/PDK-1/Akt and FoxO1, and the chronic effects of the overexpression of FoxO1 in POMC neurons on energy homeostasis has not been elucidated. To determine the extent to which PDK-1 and FoxO1 signaling in POMC neurons was responsible for energy homeostasis, we generated POMC neuron-specific Pdk1 knockout mice ( POMCPdk1−/−) and mice selectively expressing a constitutively nuclear (CN)FoxO1 or transactivation-defective (Δ256)FoxO1 in POMC neurons ( CNFoxO1POMCor Δ256FoxO1POMC). POMCPdk1−/−mice showed increased food intake and body weight accompanied by decreased expression of Pomc gene. The CNFoxO1POMCmice exhibited mild obesity and hyperphagia compared with POMCPdk1−/−mice. Although expression of the CNFoxO1 made POMCPdk1−/−mice more obese due to excessive suppression of Pomc gene, overexpression of Δ256FoxO1 in POMC neurons had no effects on metabolic phenotypes and Pomc expression levels of POMCPdk1−/−mice. These data suggest a requirement for PDK-1 and FoxO1 in transcriptional regulation of Pomc and food intake.
HOXA10 regulates endometrial GABAAπ receptor expression and membrane translocation
Authors: Sadeghi Homayoun , Taylor Hugh S.
Published: January 2010

Expression of the GABAAπ receptor has been described previously in the human endometrium in both luminal epithelium and stroma. Its expression is increased during decidualization in rodents and in the implantation window of human endometrium. Here we localized GABA π subunit receptor protein in human endometrium and identified regulators of gene expression and activation. GABAAπ was localized to the cell surface, and expression increased during the window of embryo implantation in human endometrium. The well-differentiated human endometrial adenocarcinoma cell line Ishikawa was treated with progesterone and transfected with pcDNA-HOXA10, HOXA10 siRNA, or respective controls. GABAAπ receptor mRNA expression was evaluated by real-time RT-PCR. Protein expression and localization were evaluated using immunofluorescence. GABAAπ receptor mRNA expression was increased significantly after either progesterone treatment or HOXA10 transfection. Coadministration of progesterone along with HOXA10 transfection had no additional effect on the expression of GABAAπ receptor mRNA over either agent alone. Blocking HOXA10 expression with siRNA prevented progesterone-induced GABAAπ receptor mRNA expression. Additionally, either HOXA10 or progesterone independently caused increased translocation of the GABA receptor from the cytoplasm to the cell membrane. Translocation in response to progesterone was blocked with HOXA10 siRNA. Progesterone-induced GABAAπ subunit receptor expression is likely mediated indirectly through progesterone's regulation of HOXA10 expression. Modification of subtype composition and translocation of the GABA receptor ion channel likely modulate endometrial receptivity. Whereas HOXA10 typically enhances the expression of progesterone-responsive genes, here HOXA10 expression leads to production of a less progestin-responsive GABA receptor subtype, likely buffering the effects of luteal phase progesterone on GABA receptor activity.
Placental expression of myostatin and follistatin-like-3 protein in a model of developmental programming
Authors: Peiris Hassendrini N. , Ponnampalam Anna P. , Osepchook Claire C. , Mitchell Murray D. , Green Mark P.
Published: January 2010

Maternal undernutrition during gestation is known to be detrimental to fetal development, leading to a propensity for metabolic disorders later in the adult lives of the offspring. Identifying possible mediators and physiological processes involved in modulating nutrient transport within the placenta is essential to prevent and/or develop treatments for the effects of aberrant nutrition, nutrient transfer, and detrimental changes to fetal development. A potential role for myostatin as a mediator of nutrient uptake and transport from the mother to the fetus was shown through the recent finding that myostatin acts within the human placenta to modulate glucose uptake and therefore homeostasis. The mRNA and protein expression of myostatin and its inhibitor, follistatin-like-3 (FSTL3), was studied in the placenta and skeletal muscle of a transgenerational Wistar rat model of gestational maternal undernutrition in which the F2 offspring postweaning consumed a high-fat (HF) diet. Alterations in placental characteristics and offspring phenotype, specifically glucose homeostasis, were evident in the transgenerationally undernourished (UNAD) group. Myostatin and FSTL3 protein expression were also higher ( P < 0.05) in the placentae of the UNAD compared with the control group. At maturity, UNAD HF-fed animals had higher ( P < 0.05) skeletal muscle expression of FSTL3 than control animals. In summary, maternal undernutrition during gestation results in the aberrant regulation of myostatin and FSTL3 in the placenta and skeletal muscle of subsequent generations. Myostatin, through the disruption of maternal nutrient supply to the fetus, may thus be a potential mediator of offspring phenotype.
Dihydrotestosterone alters cyclooxygenase-2 levels in human coronary artery smooth muscle cells
Authors: Osterlund Kristen L. , Handa Robert J. , Gonzales Rayna J.
Published: January 2010

Both protective and nonprotective effects of androgens on the cardiovascular system have been reported. Our previous studies show that the potent androgen receptor (AR) agonist dihydrotestosterone (DHT) increases levels of the vascular inflammatory mediator cyclooxygenase (COX)-2 in rodent cerebral arteries independent of an inflammatory stimulus. Little is known about the effects of androgens on inflammation in human vascular tissues. Therefore, we tested the hypothesis that DHT alters COX-2 levels in the absence and presence of induced inflammation in primary human coronary artery smooth muscle cells (HCASMC). Furthermore, we tested the ancillary hypothesis that DHT's effects on COX-2 levels are AR-dependent. Cells were treated with DHT (10 nM) or vehicle for 6 h in the presence or absence of LPS or IL-1β. Similar to previous observations in rodent arteries, in HCASMC, DHT alone increased COX-2 levels compared with vehicle. This effect of DHT was attenuated in the presence of the AR antagonist bicalutamide. Conversely, in the presence of LPS or IL-1β, increases in COX-2 were attenuated by cotreatment with DHT. Bicalutamide did not affect this response, suggesting that DHT-induced decreases in COX-2 levels occur independent of AR stimulation. Thus we conclude that DHT differentially influences COX-2 levels under physiological and pathophysiological conditions in HCASMC. This effect of DHT on COX-2 involves AR-dependent and- independent mechanisms, depending on the physiological state of the cell.
Inappropriate glucagon response after oral compared with isoglycemic intravenous glucose administration in patients with type 1 diabetes
Authors: Hare Kristine J. , Vilsbøll Tina , Holst Jens J. , Knop Filip K.
Published: January 2010

Hyperglucagonemia following oral glucose ingestion in patients with type 1 diabetes (and type 2 diabetes) has been claimed to result from impaired intraislet insulin inhibition of glucagon. We looked at plasma glucagon responses to the oral glucose tolerance test (OGTT) and isoglycemic intravenous glucose infusion (IIGI) in patients with type 1 diabetes. Nine patients without residual β-cell function [age: 25 ± 9 yr; body mass index (BMI): 24 ± 2 kg/m2; fasting plasma glucose (FPG): 9.5 ± 2.1 mM; Hb A1c: 8.4 ± 1.2% (mean ± SD)] and eight healthy subjects (age: 28 ± 5 yr; BMI: 24 ± 3 kg/m2; FPG: 5.3 ± 0.2 mM; Hb A1c: 5.0 ± 0.1%) were examined on two separate occasions: 4-h 50-g OGTT and IIGI. Isoglycemia during IIGIs was obtained using 53 ± 5 g of glucose in patients with type 1 diabetes and 30 ± 3 g in control subjects ( P < 0.001), resulting in gastrointestinal-mediated glucose disposal [100% × (glucoseOGTT − glucoseIIGI/glucoseOGTT)] of −6 ± 9 and 40 ± 6% ( P < 0.01), respectively. Equal glucagon suppression during the two glucose stimuli was observed in healthy subjects, whereas patients with type 1 diabetes exhibited less inhibition in response to OGTT compared with IIGI (AUC: 1,519 ± 129 vs. 1,240 ± 86 pM·4 h; P = 0.03). This difference was even more pronounced during the initial 40 min with paradoxical hypersecretion of glucagon during OGTT and suppression during IIGI (AUC: 37 ± 13 vs. −33 ± 16 pM·40 min; P = 0.02). These results suggest that the inappropriate glucagon response to glucose in patients with type 1 diabetes occurs as a consequence of the oral administration way, suggesting a role of the gastrointestinal tract, possibly via glucagonotropic signaling from gut hormones (e.g., glucose-dependent insulinotropic polypeptide), in type 1 diabetic hyperglucagonemia.
AMPK and SIRT1: a long-standing partnership?
Authors: Ruderman Neil B. , Julia Xu X. , Nelson Lauren , Cacicedo José M. , Saha Asish K. , Lan Fan , Ido Yasuo
Published: January 2010

AMP-activated protein kinase (AMPK) and the histone/protein deacetylase SIRT1 are fuel-sensing molecules that have coexisted in cells throughout evolution. When a cell's energy state is diminished, AMPK activation restores energy balance by stimulating catabolic processes that generate ATP and downregulating anabolic processes that consume ATP but are not acutely needed for survival. SIRT1 in turn is best known historically for producing genetic changes that mediate the increase in longevity caused by calorie restriction. Although the two molecules have been studied intensively for many years, only recently has it become apparent that they have similar effects on diverse processes such as cellular fuel metabolism, inflammation, and mitochondrial function. In this review we will examine the evidence that these similarities occur because AMPK and SIRT1 both regulate each other and share many common target molecules. In addition, we will discuss the clinical relevance of these interactions and in particular the possibility that their dysregulation predisposes to disorders such as type 2 diabetes and atherosclerotic cardiovascular disease and is a target for their therapy.
Mechanisms underlying epithelium-dependent relaxation in rat bronchioles: analogy to EDHF-type relaxation in rat pulmonary arteries
Authors: Kroigaard Christel , Dalsgaard Thomas , Simonsen Ulf
Published: January 2010

This study investigated the mechanisms underlying epithelium-derived hyperpolarizing factor (EpDHF)-type relaxation in rat bronchioles. Immunohistochemistry was performed, and rat bronchioles and pulmonary arteries were mounted in microvascular myographs for functional studies. An opener of small (SKCa) and intermediate (IKCa)-conductance calcium-activated potassium channels, NS309 (6,7-dichloro-1H-indole-2,3-dione 3-oxime) was used to induce EpDHF-type relaxation. IKCa and SKCa3 positive immunoreactions were observed mainly in the epithelium and endothelium of bronchioles and arteries, respectively. In 5-hydroxytryptamine (1 μM)-contracted bronchioles (828 ± 20 μm, n = 84) and U46619 (0.03 μM)-contracted arteries (720 ± 24 μm, n = 68), NS309 (0.001–10 μM) induced concentration-dependent relaxations that were reduced by epithelium/endothelium removal and by blocking IKCa channels with charybdotoxin and in bronchioles also by blocking SKCa channels with apamin. Inhibition of cyclooxygenase, nitric oxide synthase, and cytochrome 2C isoenzymes, or blockade of large (BKCa)-conductance calcium-activated potassium channels with iberiotoxin, failed to reduce NS309 relaxation. In contrast to the pulmonary arteries, relaxations to a β2-adrenoceptor agonist, salbutamol, were reduced in bronchioles by removing the epithelium or blocking IKCa and/or SKCa channels. Extracellular K+ (2–20 mM) induced relaxation in both bronchioles and arteries. An inhibitor of Na+-K+-ATPase, ouabain, abolished relaxations to NS309, salbutamol, and K+. These results suggest that IKCa and SKCa3 channels are located in the epithelium of bronchioles and endothelium of pulmonary arteries. Analog to the endothelium-derived hyperpolarizing factor (EDHF)-type relaxation in pulmonary arteries, these channels may be involved in EpDHF-type relaxation of bronchioles caused by epithelial K+ efflux followed by activation of Na+-K+-ATPase in the underlying smooth muscle layer.
Synaptic and membrane properties of parasympathetic ganglionic neurons innervating mouse trachea and bronchi
Authors: Weigand Letitia A. , Myers Allen C.
Published: January 2010

The pathophysiology of airway diseases, such as asthma, is increasingly studied using transgenic mice and other mouse models of airway inflammation where allergen-induced changes in airway smooth muscle tone and mucous secretion is due, in part, to activation of preganglionic airway parasympathetic nerves. Ganglionic parasympathetic neurons located in the airways in several species, including humans, have anatomical and electrophysiological properties that limit transmission of preganglionic synaptic input. In this study, intracellular recordings were made from neurons in parasympathetic ganglia located on the trachea and bronchi of adult mice to determine electrophysiological properties associated with regulation of transmission of preganglionic input. Ganglionic neurons were characterized as having either tonic or phasic action potential accommodation patterns. Tonic neurons responded with repetitive action potentials sustained throughout a depolarizing current step, whereas phasic neurons generated one or a burst of action potential(s) and accommodated. A small subset displayed both patterns. Phasic neurons could be further differentiated as usually having either short- or long-duration afterhyperpolarizing potential following single and multiple action potentials. In most cells, stimulation of preganglionic nerves elicited one population of nicotinic fast excitatory postsynaptic potentials that were graded in amplitude, usually suprathreshold for action potential generation, and did not decrease in amplitude during higher frequency stimulation. Dye injection into the neurons revealed that dendrites were either absent or very short. These results provide evidence that in contrast to the characteristics of airway parasympathetic neurons reported in other species, including human, the electrophysiological and synaptic properties, and anatomical characteristics of mouse lower airway ganglionic neurons, are less associated with integration of presynaptic input.
Simulating Microinjection Experiments in a Novel Model of the Rat Sleep-Wake Regulatory Network
Authors: Diniz Behn Cecilia G. , Booth Victoria
Published: January 2010

This study presents a novel mathematical modeling framework that is uniquely suited to investigating the structure and dynamics of the sleep-wake regulatory network in the brain stem and hypothalamus. It is based on a population firing rate model formalism that is modified to explicitly include concentration levels of neurotransmitters released to postsynaptic populations. Using this framework, interactions among primary brain stem and hypothalamic neuronal nuclei involved in rat sleep-wake regulation are modeled. The model network captures realistic rat polyphasic sleep-wake behavior consisting of wake, rapid eye movement (REM) sleep, and non-REM (NREM) sleep states. Network dynamics include a cyclic pattern of NREM sleep, REM sleep, and wake states that is disrupted by simulated variability of neurotransmitter release and external noise to the network. Explicit modeling of neurotransmitter concentrations allows for simulations of microinjections of neurotransmitter agonists and antagonists into a key wake-promoting population, the locus coeruleus (LC). Effects of these simulated microinjections on sleep-wake states are tracked and compared with experimental observations. Agonist/antagonist pairs, which are presumed to have opposing effects on LC activity, do not generally induce opposing effects on sleep-wake patterning because of multiple mechanisms for LC activation in the network. Also, different agents, which are presumed to have parallel effects on LC activity, do not induce parallel effects on sleep-wake patterning because of differences in the state dependence or independence of agonist and antagonist action. These simulation results highlight the utility of formal mathematical modeling for constraining conceptual models of the sleep-wake regulatory network.
Gene expression of the liver in response to chronic hypoxia
Authors: Baze Monica M. , Schlauch Karen , Hayes Jack P.
Published: January 2010

Hypoxia is an important ecological, evolutionary, and biomedical stressor. While physiological acclimatization of mammals to hypoxia is well studied, the variation in gene expression that underlies acclimatization is not well studied. We acclimatized inbred mice for 32 days to hypoxic conditions that simulated altitudes of 1400, 3000, and 4500 m. We used oligonucleotide microarrays to measure changes in steady-state abundance of mRNA in the livers of these mice. Mice exposed to more severe hypoxia (simulated altitude of 4500 m) were smaller in mass and had higher hematocrit than mice exposed to less severe hypoxia. ANOVA and false discovery rate tests indicated that 580 genes were significantly differentially expressed in response to chronic hypoxia. Few of these 580 genes have previously been reported to respond to hypoxia. In contrast, many of these 580 genes belonged to same functional groups typically respond to acute hypoxia. That is, both chronic and acute hypoxia elicit changes in transcript abundance for genes involved in angiogenesis, glycolysis, lipid metabolism, carbohydrate metabolism, and protein amino acid phosphorylation, but the particular genes affected by the two types of hypoxia were mostly different. Numerous genes affecting the immune system were differentially expressed in response to chronic hypoxia, which supports recently proposed hypotheses that link immune function and hypoxia. Furthermore, our results discovered novel elevated mRNA abundance of genes involved in hematopoiesis and oxygen transport not reported previously, but consistent with extreme hematocrits found in hypoxic mice.
Existence of Homoclinic Orbits for Hamiltonian Systems with Superquadratic Potentials
Authors: Ding Jian , Xu Junxiang , Zhang Fubao
Published: January 2010

This paper concerns solutions for the Hamiltonian system: .
Here H(t, z) = (1/2)z · Lz + W(t, z), L
is a 2N × 2N
symmetric matrix, and W ∈ C1(ℝ × ℝ2N, ℝ). We consider the case that 0 ∈ σc(−(𝒥(d/dt) + L)) and W
satisfies some superquadratic condition different from the type of Ambrosetti‐Rabinowitz. We study this
problem by virtue of some weak linking theorem recently developed and prove the
existence of homoclinic orbits.
Phenotypic and Genotypic Characterization ofStaphylococcus aureusStrains from Italian Dairy Products
Authors: Morandi Stefano , Brasca Milena , Andrighetto Cristian , Lombardi Angiolella , Lodi Roberta
Published: January 2010

Staphylococcus aureusis a known major cause of foodborne illnesses, and milk and dairy products are often contaminated by enterotoxigenic strains of this bacterium. In the present study, 122S. aureusisolates collected from different dairy products were characterised by phenotypic properties, by the distribution of genes encoding staphylococcal enterotoxins (sea,sec,sed,seg,seh,sei,sej, andsel) and by randomly amplified polymorphic DNA PCR (RAPD-PCR). Moreover, strain resistance to vancomycin and methicillin (oxacillin) was studied. The differences in the RAPD-PCR profiles obtained with the primers M13 and AP4 revealed the presence of a great genetic heterogeneity among the differentS. aureusstrains. Using the primer AP4 and M13, eight groups were distinguished by RAPD-PCR cluster analysis, although, except in few cases, it was not possible to correlate the isolates of different animal species (cow or ovine) with the presence ofsegenes. None of the isolates showed resistance to vancomycin or methicillin.
Approximate Fixed Points for Nonexpansive and Quasi-Nonexpansive Mappings in Hyperspaces
Authors: Liu Zeqing , Ume Jeong Sheok , Kang Shin Min
Published: January 2010

This paper provides a few convergence results of the Ishikawa iteration sequence with errors for nonexpansive and quasi-nonexpansive mappings in hyperspaces. The results presented in this paper improve and generalize some results in the literature.
Reproducible RNA Preparation from Sugarcane and Citrus for Functional Genomic Applications
Authors: Damaj Mona B. , Beremand Phillip D. , Buenrostro-Nava Marco T. , Riedel Beth , Molina Joe J. , Kumpatla Siva P. , Thomas Terry L. , Mirkov T. Erik
Published: January 2010

High‐throughput functional genomic procedures depend on the quality of the RNA used. Copurifying molecules can negatively impact the functionality of some plant RNA preparations employed in these procedures. We present a simplified, rapid, and scalable SDS/phenol‐based method that provides the high‐quantity and ‐quality RNA required by the newly emerging biotechnology applications. The method is applied to isolating RNA from tissues of two biotechnologically important crop plants, sugarcane and citrus, which provide a challenge due to the presence of fiber, polysaccharides, or secondary metabolites. The RNA isolated by this method is suitable for several downstream applications including northern blot hybridization, microarray analysis, and quantitative RT‐PCR. This method has been used in a diverse range of projects ranging from screening plant lines overexpressing mammalian genes to analyzing plant responses to viral infection and defense signaling molecules.
On Concordance Measures for Discrete Data and Dependence Properties of Poisson Model
Authors: Bouezmarni Taoufik , Mesfioui Mhamed , Tajar Abdelouahid
Published: January 2010

We study Kendall′s tau and Spearman′s rho concordance measures for discrete
variables. We mainly provide their best bounds using positive dependence properties. These
bounds are difficult to write down explicitly in general. Here, we give the explicit formula of the
best bounds in a particular Fréchet space in order to understand the behavior of the ranges of
these measures. Also, based on the empirical copula which is viewed as a discrete distribution, we
propose a new estimator of the copula function. Finally, we give useful dependence properties of
the bivariate Poisson distribution and show the relationship between parameters of the Poisson
distribution and both tau and rho.
The Stability of a Quadratic Functional Equation with the Fixed Point Alternative
Authors: Park Choonkil , Kim Ji-Hye
Published: January 2010

Lee, An and Park introduced the quadratic
functional equation f(2x + y) + f(2x − y) = 8f(x) + 2f(y) and proved the stability of the quadratic functional equation in the spirit of Hyers, Ulam and Th. M. Rassias. Using the fixed point method, we prove the generalized Hyers‐Ulam stability of the quadratic
functional equation in Banach spaces.
Synthetic Biology: Tools to Design, Build, and Optimize Cellular Processes
Authors: Young Eric , Alper Hal
Published: January 2010

The general central dogma frames the emergent properties of life, which make biology both necessary and difficult to engineer. In a process engineering paradigm, each biological process stream and process unit is heavily influenced by regulatory interactions and interactions with the surrounding environment. Synthetic biology is developing the tools and methods that will increase control over these interactions, eventually resulting in an integrative synthetic biology that will allow ground-up cellular optimization. In this review, we attempt to contextualize the areas of synthetic biology into three tiers: (1) the process units and associated streams of the central dogma, (2) the intrinsic regulatory mechanisms, and (3) the extrinsic physical and chemical environment. Efforts at each of these three tiers attempt to control cellular systems and take advantage of emerging tools and approaches. Ultimately, it will be possible to integrate these approaches and realize the vision of integrative synthetic biology when cells are completely rewired for biotechnological goals. This review will highlight progress towards this goal as well as areas requiring further research.
AROMA (AGU Robotic Optical Monitor for Astrophysical Objects)
Authors: Takahashi Ichiro , Tsunashima Kosuke , Shiraki Takayuki , Kojima Toru , Yoshida Atsumasa , Nakagawa Yujin E.
Published: January 2010

We are developing and operating the automatic telescope Aoyama Gakuin
University Robotic Optical Monitor for Astrophysical objects (AROMA) in the Sagamihara Campus of Aoyama Gakuin University. AROMA is composed of two observational equipments, AROMA‐N and AROMA‐W. AROMA‐N is a 30‐cm aperture telescope system for rapid follow‐up observations of the optical afterglow of gamma‐ray bursts. Automatic analysis pipeline for AROMA‐N has been developed and is working. The other observational equipment AROMA‐W is a wide‐field observation system using multiple digital single‐lens reflex cameras. It covers a large FOV of about 35° × 25°. AROMAW provides photometric data in four bands with a limiting V magnitude of about 12‐13 mag. Software to analyze massive image data automatically is being developed. We plan to monitor the luminosities of all the stars in the FOV of AROMA‐W, detect optical transients, and trigger a follow‐up observation with AROMA‐N. We report on the development status and observational results of AROMA.
Pilot‐Aided Sequential Monte Carlo Estimation of Phase Distortions and Transmitted Symbols in Multicarrier Systems
Authors: Septier François , Delignon Yves , Menhaj-Rivenq Atika , Garnier Christelle
Published: January 2010

We address the challenging problem of the joint estimation of transmitted symbols and phase distortions in standardized multicarrier systems, including pilot or virtual subcarriers. These subcarriers create time correlation on the useful transmitted OFDM signal that we propose to take into account by an autoregressive model. Because the phase distortions are nonlinear, we set the joint estimation algorithm on the framework of the Sequential Monte Carlo methods. Simulation results are provided in terms of bit error rate (BER) and mean square error (MSE); they highlight the efficiency and the robustness of the estimator.
Variance Bound of ACF Estimation of One Block of fGn with LRD
Authors: Li Ming , Zhao Wei
Published: January 2010

This paper discusses the estimation of autocorrelation function (ACF) of fractional Gaussian noise (fGn) with long‐range dependence (LRD). A variance bound of ACF estimation of one block of fGn with LRD for a given value of the Hurst parameter (H) is given. The present bound provides a guideline to require the block size to guarantee that the variance of ACF estimation of one block of fGn with LRD for a givenHvalue does not exceed the predetermined variance bound regardless of the start point of the block. In addition, the present result implies that the error of ACF estimation of a block of fGn with LRD depends only on the number of data points within the sample and not on the actual sample length in time. For a given block size, the error is found to be larger for fGn with stronger LRD than that with weaker LRD.
Silencing of RON Receptor Signaling Promotes Apoptosis and Gemcitabine Sensitivity in Pancreatic Cancers
Authors: Logan-Collins Jocelyn , Thomas Ryan M. , Yu Peter , Jaquish Dawn , Mose Evangeline , French Randall , Stuart William , McClaine Rebecca , Aronow Bruce , Hoffman Robert M. , Waltz Susan E. , Lowy Andrew M.
Published: January 2010

The RON receptor tyrosine kinase is overexpressed in premalignant pancreatic intraepithelial neoplasia (PanIN) and in the majority of pancreatic cancers. In pancreatic cells, RON is an important K-Ras effector and RON ligand can enhance migration/invasion and apoptotic resistance. However, the pathobiological significance of RON overexpression in pancreatic cancers has yet to be fully established. In this study, we demonstrate that RON signaling mediates a unique transcriptional program that is conserved between cultured cells derived from murine PanIN or human pancreatic cancer cells grown as subcutaneous tumor xenografts. In both systems, RON signaling regulates expression of genes implicated in cancer-cell survival, including Bcl-2 and the transcription factors signal transducer and activator of transcription 3 (STAT 3) and c-Jun. shRNA-mediated silencing of RON in pancreatic cancer xenografts inhibited their growth, primarily by increasing susceptibility to apoptosis and by sensitizing them to gemcitabine treatment. Escape from RON silencing was associated with re-expression of RON and/or expression of phosphorylated forms of the related c-Met or epidermal growth factor receptors. These findings indicate that RON signaling mediates cell survival and in vivo resistance to gemcitabine in pancreatic cancer, and they reveal mechanisms through which pancreatic cancer cells may circumvent RON-directed therapies. Cancer Res; 70(3); 1130–40
ZNF238 Is Expressed in Postmitotic Brain Cells and Inhibits Brain Tumor Growth
Authors: Tatard Valérie M. , Xiang Chaomei , Biegel Jaclyn A. , Dahmane Nadia
Published: January 2010

Brain tumors such as medulloblastoma (MB) and glioblastoma multiforme (GBM) can derive from neural precursors. For instance, many MBs are thought to arise from the uncontrolled proliferation of cerebellar granule neuron precursors (GNP). GNPs normally proliferate in early postnatal stages in mice but then they become postmitotic and differentiate into granule neurons. The proliferation of neural precursors, GNPs, as well as at least subsets of GBM and MB depends on Hedgehog signaling. However, the gene functions that are lost or suppressed in brain tumors and that normally promote the proliferation arrest and differentiation of precursors remain unclear. Here we have identified a member of the BTB-POZ and zinc finger family, ZNF238, as a factor highly expressed in postmitotic GNPs and differentiated neurons. In contrast, proliferating GNPs as well as MB and GBM express low or no ZNF238. Functionally, inhibition of ZNF238 expression in mouse GNPs decreases the expression of the neuronal differentiation markers MAP2 and NeuN and downregulates the expression of the cell cycle arrest protein p27, a regulator of GNP differentiation. Conversely, reinstating ZNF238 expression in MB and GBM cells drastically decreases their proliferation and promotes cell death. It also downregulates cyclin D1 while increasing MAP2 and p27 protein levels. Importantly, ZNF238 antagonizes MB and GBM tumor growth in vivo in xenografts. We propose that the antiproliferative functions of ZNF238 in normal GNPs and possibly other neural precursors counteract brain tumor formation. ZNF238 is thus a novel brain tumor suppressor and its reactivation in tumors could open a novel anticancer strategy. Cancer Res; 70(3); 1236–46
Efficacious Immune Therapy in Chronic Myelogenous Leukemia (CML) Recognizes Antigens That Are Expressed on CML Progenitor Cells
Authors: Biernacki Melinda A. , Marina Ovidiu , Zhang Wandi , Liu Fenglong , Bruns Ingmar , Cai Ann , Neuberg Donna , Canning Christine M. , Alyea Edwin P. , Soiffer Robert J. , Brusic Vladimir , Ritz Jerome , Wu Catherine J.
Published: January 2010

Curative effects of graft-versus-leukemia–based therapies such as donor lymphocyte infusion (DLI) for chronic myelogenous leukemia (CML) may result from immunologic ablation of self-renewing CML progenitor cells. Patients who achieved durable remissions after DLI developed a significant B-cell lymphocytosis after treatment, which did not occur in patients who were unresponsive to DLI. In this study, we identified antigen targets of this B-cell response by probing two immunoproteomic platforms with plasma immunoglobulins from seven CML patients with clinically apparent graft-versus-leukemia responses after DLI. In total, 62 antigens elicited greater reactivity from post-DLI versus pre-DLI plasma. Microarray analysis revealed that >70% of the antigens were expressed in CML CD34+ cells, suggesting that expression in malignant progenitor cells is a feature common to antibody targets of DLI. We confirmed elevated expression of three target antigens (RAB38, TBCE, and DUSP12) in CML that together consistently elicited antibody responses in 18 of 21 of an additional cohort of CML patients with therapeutic responses, but not in normal donors and rarely in non-CML patients. In summary, immunologic targets of curative DLI responses include multiple antigens on CML progenitor cells, identifying them as potential immunogens for vaccination and/or monitoring of immunotherapeutics designed to eliminate myeloid leukemia stem cells. Cancer Res; 70(3); 906–15
Phase I Trial of Intraperitoneal Administration of an Oncolytic Measles Virus Strain Engineered to Express Carcinoembryonic Antigen for Recurrent Ovarian Cancer
Authors: Galanis Evanthia , Hartmann Lynn C. , Cliby William A. , Long Harry J. , Peethambaram Prema P. , Barrette Brigitte A. , Kaur Judith S. , Haluska Paul J. , Aderca Ileana , Zollman Paula J. , Sloan Jeff A. , Keeney Gary , Atherton Pamela J. , Podratz Karl C. , Dowdy Sean C. , Stanhope C. Robert , Wilson Timothy O. , Federspiel Mark J. , Peng Kah-Whye , Russell Stephen J.
Published: January 2010

Edmonston vaccine strains of measles virus (MV) have shown significant antitumor activity in preclinical models of ovarian cancer. We engineered MV to express the marker peptide carcinoembryonic antigen (MV-CEA virus) to also permit real-time monitoring of viral gene expression in tumors in the clinical setting. Patients with Taxol and platinum-refractory recurrent ovarian cancer and normal CEA levels were eligible for this phase I trial. Twenty-one patients were treated with MV-CEA i.p. every 4 weeks for up to 6 cycles at seven different dose levels (103–109 TCID50). We observed no dose-limiting toxicity, treatment-induced immunosuppression, development of anti-CEA antibodies, increase in anti-MV antibody titers, or virus shedding in urine or saliva. Dose-dependent CEA elevation in peritoneal fluid and serum was observed. Immunohistochemical analysis of patient tumor specimens revealed overexpression of measles receptor CD46 in 13 of 15 patients. Best objective response was dose-dependent disease stabilization in 14 of 21 patients with a median duration of 92.5 days (range, 54–277 days). Five patients had significant decreases in CA-125 levels. Median survival of patients on study was 12.15 months (range, 1.3–38.4 months), comparing favorably to an expected median survival of 6 months in this patient population. Our findings indicate that i.p. administration of MV-CEA is well tolerated and results in dose-dependent biological activity in a cohort of heavily pretreated recurrent ovarian cancer patients. Cancer Res; 70(3); 875–82
BRCA1 Represses Amphiregulin Gene Expression
Authors: Lamber Ekaterina P. , Horwitz Andrew A. , Parvin Jeffrey D.
Published: January 2010

BRCA1, the breast cancer- and ovarian cancer-specific tumor suppressor, can be a transcriptional repressor or a transcriptional activator, depending on the promoter context. To identify the genes activated or repressed by BRCA1, we have analyzed microarray results from cells depleted of BRCA1 and revealed a number of genes regulated by BRCA1 on the level of transcription. Among the genes repressed by BRCA1, we have identified amphiregulin (AREG) and early growth response-1 (EGR1). Results indicate that BRCA1 regulates AREG transcription directly through binding to the AREG promoter, however, we could not detect BRCA1 on the EGR1 promoter, suggesting that EGR1 is indirectly regulated by BRCA1. In an attempt to identify the mechanism of the AREG transcriptional repression by BRCA1, we have mapped two independent BRCA1 response elements on the AREG located at positions −202/−182 and +19/+122. BRCA1 depletion leads to induction of the AREG protein. Taken together, our data build the connection between BRCA1 loss of function and AREG upregulation—a change in gene expression often observed in breast cancer. Cancer Res; 70(3); 996–1005
Chemogenomic Profiling Provides Insights into the Limited Activity of Irreversible EGFR Inhibitors in Tumor Cells Expressing the T790M EGFR Resistance Mutation
Authors: Sos Martin L. , Rode Haridas B. , Heynck Stefanie , Peifer Martin , Fischer Florian , Klüter Sabine , Pawar Vijaykumar G. , Reuter Cecile , Heuckmann Johannes M. , Weiss Jonathan , Ruddigkeit Lars , Rabiller Matthias , Koker Mirjam , Simard Jeffrey R. , Getlik Matthäus , Yuza Yuki , Chen Tzu-Hsiu , Greulich Heidi , Thomas Roman K. , Rauh Daniel
Published: January 2010

Reversible epidermal growth factor receptor (EGFR) inhibitors are the first class of small molecules to improve progression-free survival of patients with EGFR-mutated lung cancers. Second-generation EGFR inhibitors introduced to overcome acquired resistance by the T790M resistance mutation of EGFR have thus far shown limited clinical activity in patients with T790M-mutant tumors. In this study, we systematically analyzed the determinants of the activity and selectivity of the second-generation EGFR inhibitors. A focused library of irreversible as well as structurally corresponding reversible EGFR-inhibitors was synthesized for chemogenomic profiling involving over 79 genetically defined NSCLC and 19 EGFR-dependent cell lines. Overall, our results show that the growth-inhibitory potency of all irreversible inhibitors against the EGFRT790M resistance mutation was limited by reduced target inhibition, linked to decreased binding velocity to the mutant kinase. Combined treatment of T790M-mutant tumor cells with BIBW-2992 and the phosphoinositide-3-kinase/mammalian target of rapamycin inhibitor PI-103 led to synergistic induction of apoptosis. Our findings offer a mechanistic explanation for the limited efficacy of irreversible EGFR inhibitors in EGFRT790M gatekeeper-mutant tumors, and they prompt combination treatment strategies involving inhibitors that target signaling downstream of the EGFR. Cancer Res; 70(3); 868–74
Resveratrol Promotes Autophagic Cell Death in Chronic Myelogenous Leukemia Cells via JNK-Mediated p62/SQSTM1 Expression and AMPK Activation
Authors: Puissant Alexandre , Robert Guillaume , Fenouille Nina , Luciano Frederic , Cassuto Jill-Patrice , Raynaud Sophie , Auberger Patrick
Published: January 2010

Autophagy that is induced by starvation or cellular stress can enable cancer cell survival by sustaining energy homeostasis and eliminating damaged organelles and proteins. In response to stress, cancer cells have been reported to accumulate the protein p62/SQSTM1 (p62), but its role in the regulation of autophagy is controversial. Here, we report that the plant phytoalexin resveratrol (RSV) triggers autophagy in imatinib-sensitive and imatinib-resistant chronic myelogenous leukemia (CML) cells via JNK-dependent accumulation of p62. JNK inhibition or p62 knockdown prevented RSV-mediated autophagy and antileukemic effects. RSV also stimulated AMPK, thereby inhibiting the mTOR pathway. AMPK knockdown or mTOR overexpression impaired RSV-induced autophagy but not JNK activation. Lastly, p62 expression and autophagy in CD34+ progenitors from patients with CML was induced by RSV, and disrupting autophagy protected CD34+ CML cells from RSV-mediated cell death. We concluded that RSV triggered autophagic cell death in CML cells via both JNK-mediated p62 overexpression and AMPK activation. Our findings show that the JNK and AMPK pathways can cooperate to eliminate CML cells via autophagy. Cancer Res; 70(3); 1042–52
PSF1, a DNA Replication Factor Expressed Widely in Stem and Progenitor Cells, Drives Tumorigenic and Metastatic Properties
Authors: Nagahama Yumi , Ueno Masaya , Miyamoto Satoru , Morii Eiichi , Minami Takashi , Mochizuki Naoki , Saya Hideyuki , Takakura Nobuyuki
Published: January 2010

PSF1 (partner of sld five 1) is an evolutionarily conserved DNA replication factor implicated in DNA replication in lower species that is strongly expressed in a wide range of normal stem cell populations and progenitor cell populations. Because stem and progenitor cells possess high proliferative capacity, we hypothesized that PSF1 may play an important role in tumor growth. To begin to investigate PSF1 function in cancer cells, we cloned the mouse PSF1 promoter and generated lung and colon carcinoma cells that stably express a PSF1 promoter-reporter gene. Reporter expression in cells correlated with endogenous PSF1 mRNA expression. In a tumor cell xenograft model, high levels of reporter expression correlated with high proliferative activity, serial transplantation potential, and metastatic capability. Notably, cancer cells expressing reporter levels localized to perivascular regions in tumors and displayed expression signatures related to embryonic stem cells. RNAi-mediated silencing of endogenous PSF1 inhibited cancer cell growth by disrupting DNA synthesis and chromosomal segregation. These findings implicate PSF1 in tumorigenesis and offer initial evidence of its potential as a theranostic target. Cancer Res; 70(3); 1215–24
PERK–Dependent Regulation of Ceramide Synthase 6 and Thioredoxin Play a Key Role inmda-7/IL-24–Induced Killing of Primary Human Glioblastoma Multiforme Cells
Authors: Yacoub Adly , Hamed Hossein A. , Allegood Jeremy , Mitchell Clint , Spiegel Sarah , Lesniak Maciej S. , Ogretmen Besim , Dash Rupesh , Sarkar Devanand , Broaddus William C. , Grant Steven , Curiel David T. , Fisher Paul B. , Dent Paul
Published: January 2010

Melanoma differentiation associated gene-7(mda-7) encodes IL-24, a cytokine that can selectively trigger apoptosis in transformed cells. Recombinant mda-7 adenovirus (Ad.mda-7) effectively kills glioma cells, offering a novel gene therapy strategy to address deadly brain tumors. In this study, we defined the proximal mechanisms by which Ad-mda-7 kills glioma cells. Key factors implicated included activation of the endoplasmic reticulum stress kinase protein kinase R–like endoplasmic reticulum kinase (PERK), Ca++ elevation, ceramide generation and reactive oxygen species (ROS) production. PERK inhibition blocked ceramide or dihydroceramide generation, which were critical for Ca++ induction and subsequent ROS formation. Activation of autophagy and cell death relied upon ROS formation, the inhibition of which ablated Ad.mda-7–killing activity. In contrast, inhibiting TRX induced by Ad.MDA-7 enhanced tumor cytotoxicity and improved animal survival in an orthotopic tumor model. Our findings indicate that mda-7/IL-24 induces an endoplasmic reticulum stress response that triggers production of ceramide, Ca2+, and ROS, which in turn promote glioma cell autophagy and cell death. Cancer Res; 70(3); 1120–9
Radiosensitization of Epidermal Growth Factor Receptor/HER2–Positive Pancreatic Cancer Is Mediated by Inhibition of Akt Independent of Ras Mutational Status
Authors: Kimple Randall J. , Vaseva Angelina V. , Cox Adrienne D. , Baerman Kathryn M. , Calvo Benjamin F. , Tepper Joel E. , Shields Janiel M. , Sartor Carolyn I.
Published: January 2010

Purpose: Epidermal growth factor receptor (EGFR) family members (e.g., EGFR, HER2, HER3, and HER4) are commonly overexpressed in pancreatic cancer. We investigated the effects of inhibition of EGFR/HER2 signaling on pancreatic cancer to elucidate the role(s) of EGFR/HER2 in radiosensitization and to provide evidence in support of further clinical investigations.

Experimental Design: Expression of EGFR family members in pancreatic cancer lines was assessed by quantitative reverse transcription-PCR. Cell growth inhibition was determined by MTS assay. The effects of inhibition of EGFR family receptors and downstream signaling pathways on in vitro radiosensitivity were evaluated using clonogenic assays. Growth delay was used to evaluate the effects of nelfinavir on in vivo tumor radiosensitivity.

Results: Lapatinib inhibited cell growth in four pancreatic cancer cell lines, but radiosensitized only wild-type K-ras–expressing T3M4 cells. Akt activation was blocked in a wild-type K-ras cell line, whereas constitutive phosphorylation of Akt and extracellular signal-regulated kinase (ERK) was seen in lines expressing mutant K-ras. Overexpression of constitutively active K-ras (G12V) abrogated lapatinib-mediated inhibition of both Akt phosphorylation and radiosensitization. Inhibition of MAP/ERK kinase/ERK signaling with U0126 had no effect on radiosensitization, whereas inhibition of activated Akt with LY294002 (enhancement ratio, 1.2-1.8) or nelfinavir (enhancement ratio, 1.2-1.4) radiosensitized cells regardless of K-ras mutation status. Oral nelfinavir administration to mice bearing mutant K-ras–containing Capan-2 xenografts resulted in a greater than additive increase in radiation-mediated tumor growth delay (synergy assessment ratio of 1.5).

Conclusions: Inhibition of EGFR/HER2 enhances radiosensitivity in wild-type K-ras pancreatic cancer. Nelfinavir, and other phosphoinositide 3-kinase/Akt inhibitors, are effective pancreatic radiosensitizers regardless of K-ras mutation status. Clin Cancer Res; 16(3); 912–23
Suppression of Liver Tumor Growth and Metastasis by Adiponectin in Nude Mice through Inhibition of Tumor Angiogenesis and Downregulation of Rho Kinase/IFN-Inducible Protein 10/Matrix Metalloproteinase 9 Signaling
Authors: Man Kwan , Ng Kevin T.P. , Xu Aimin , Cheng Qiao , Lo Chung Mau , Xiao Jiang Wei , Sun Bai Shun , Lim Zophia X.H. , Cheung Jerry S. , Wu Ed X. , Sun Chris K.W. , Poon Ronnie T.P. , Fan Sheung Tat
Published: January 2010

Purpose: We aimed to investigate the effects of adiponectin on liver cancer growth and metastasis and explore the underlying mechanisms.

Experimental Design: An orthotopic liver tumor nude mice model with distant metastatic potential was applied. Either Ad-adiponectin (1 × 108; treatment group) or Ad-luciferase (control group) was injected via portal vein after tumor implantation. Tumor growth and metastasis were monitored by Xenogen In vivo Imaging System. Hepatic stellate cell activation by α-smooth muscle actin staining, microvessel density by CD34 staining, macrophage infiltration in tumor tissue, and cell signaling leading to invasion, migration [Rho kinase (ROCK), IFN-inducible protein 10 (IP10), and matrix metalloproteinase 9], and angiogenesis [vascular endothelial growth factor (VEGF) and angiopoietin 1] were also compared. Tumor-nontumor margin was examined under electron microscopy. Direct effects of adiponectin on liver cancer cells and endothelial cells were further investigated by a series of functional studies.

Results: Tumor growth was significantly inhibited by adiponectin treatment, accompanied by a lower incidence of lung metastasis. Hepatic stellate cell activation and macrophage infiltration in the liver tumors were suppressed by adiponectin treatment, along with decreased microvessel density. The treatment group had less Ki-67–positive tumor cells and downregulated protein expression of ROCK1, proline-rich tyrosine kinase 2, and VEGF. Tumor vascular endothelial cell damage was found in the treatment group under electron microscopy. In vitro functional study showed that adiponectin not only downregulated the ROCK/IP10/VEGF signaling pathway but also inhibited the formation of lamellipodia, which contribute to cell migration.

Conclusion: Adiponectin treatment significantly inhibited liver tumor growth and metastasis by suppression of tumor angiogenesis and downregulation of the ROCK/IP10/matrix metalloproteinase 9 pathway. Clin Cancer Res; 16(3); 967–77