bluuebunny/crossref_metadata_2025 huggingface dataset:
Altered Plasticity in Hippocampal CA1, But Not Dentate Gyrus, Following Long-Term Environmental Enrichment
Authors: Eckert Michael J. , Bilkey David K. , Abraham Wickliffe C.
Published: April 2010

Exposure to an enriched environment can improve cognitive functioning in normal animals as well as in animal models of neurological disease and impairment. However, the physiological processes that mediate these changes are poorly understood. Previously we and others have found changes in hippocampal synaptic transmission and plasticity after 2–4 wk of enrichment although others have not observed effects. To determine whether long-term enrichment produces more robust changes, we housed rats continuously in an enriched environment for a minimum of 3 mo and then tested for effects on hippocampal physiology in vitro and in vivo. Enriched housing improved spatial learning compared with social and isolated housing, but surprisingly this was not accompanied by changes in basal synaptic transmission in either CA1 or the dentate gyrus as measured either in vitro or in vivo. This lack of change may reflect the operation of homeostatic mechanisms that keep global synaptic weights within a narrow range. In tests of synaptic plasticity, the induction of long-term potentiation was not changed in either CA1 or the dentate gyrus. However, in CA1 of enriched rats, there was less long-term depression in stratum radiatum, less depotentiation in stratum oriens, and altered paired-pulse inhibition of population spikes evoked in stratum oriens. These effects suggest that there are altered synaptic and network dynamics in hippocampal CA1 that contribute to the enrichment-related cognitive improvement.
Confidence-Related Decision Making
Authors: Insabato Andrea , Pannunzi Mario , Rolls Edmund T. , Deco Gustavo
Published: April 2010

Neurons have been recorded that reflect in their firing rates the confidence in a decision. Here we show how this could arise as an emergent property in an integrate-and-fire attractor network model of decision making. The attractor network has populations of neurons that respond to each of the possible choices, each biased by the evidence for that choice, and there is competition between the attractor states until one population wins the competition and finishes with high firing that represents the decision. Noise resulting from the random spiking times of individual neurons makes the decision making probabilistic. We also show that a second attractor network can make decisions based on the confidence in the first decision. This system is supported by and accounts for neuronal responses recorded during decision making and makes predictions about the neuronal activity that will be found when a decision is made about whether to stay with a first decision or to abort the trial and start again. The research shows how monitoring can be performed in the brain and this has many implications for understanding cognitive functioning.
Genetic architecture of voluntary exercise in an advanced intercross line of mice
Authors: Kelly Scott A. , Nehrenberg Derrick L. , Peirce Jeremy L. , Hua Kunjie , Steffy Brian M. , Wiltshire Tim , Pardo-Manuel de Villena Fernando , Garland Theodore , Pomp Daniel
Published: April 2010

Exercise is essential for health, yet the amount, duration, and intensity that individuals engage in are strikingly variable, even under prescription. Our focus was to identify the locations and effects of quantitative trait loci (QTL) controlling genetic predisposition for exercise-related traits, utilizing a large advanced intercross line (AIL) of mice. This AIL (G4) population originated from a reciprocal cross between mice with genetic propensity for increased voluntary exercise [high-runner (HR) line, selectively bred for increased wheel running] and the inbred strain C57BL/6J. After adjusting for family structure, we detected 32 significant and 13 suggestive QTL representing both daily running traits (distance, duration, average speed, and maximum speed) and the mean of these traits on days 5 and 6 (the selection criteria for HR) of a 6-day test conducted at 8 wk of age, with many colocalizing to similar genomic regions. Additionally, seven significant and five suggestive QTL were observed for the slope and intercept of a linear regression across all 6 days of running, some representing a combination of the daily traits. We also observed two significant and two suggestive QTL for body mass before exercise. These results, from a well-defined animal model, reinforce a genetic basis for the predisposition to engage in voluntary exercise, dissect this predisposition into daily segments across a continuous time period, and present unique QTL that may provide insight into the initiation, continuation, and temporal pattern of voluntary activity in mammals.
High-resolution cardiovascular function confirms functional orthology of myocardial contractility pathways in zebrafish
Authors: Shin Jordan T. , Pomerantsev Eugene V. , Mably John D. , MacRae Calum A.
Published: April 2010

Phenotype-driven screens in larval zebrafish have transformed our understanding of the molecular basis of cardiovascular development. Screens to define the genetic determinants of physiological phenotypes have been slow to materialize as a result of the limited number of validated in vivo assays with relevant dynamic range. To enable rigorous assessment of cardiovascular physiology in living zebrafish embryos, we developed a suite of software tools for the analysis of high-speed video microscopic images and validated these, using established cardiomyopathy models in zebrafish as well as modulation of the nitric oxide (NO) pathway. Quantitative analysis in wild-type fish exposed to NO or in a zebrafish model of dilated cardiomyopathy demonstrated that these tools detect significant differences in ventricular chamber size, ventricular performance, and aortic flow velocity in zebrafish embryos across a large dynamic range. These methods also were able to establish the effects of the classic pharmacological agents isoproterenol, ouabain, and verapamil on cardiovascular physiology in zebrafish embryos. Sequence conservation between zebrafish and mammals of key amino acids in the pharmacological targets of these agents correlated with the functional orthology of the physiological response. These data provide evidence that the quantitative evaluation of subtle physiological differences in zebrafish can be accomplished at a resolution and with a dynamic range comparable to those achieved in mammals and provides a mechanism for genetic and small-molecule dissection of functional pathways in this model organism.
Physiology of Kidney Renin
Authors: Castrop Hayo , Höcherl Klaus , Kurtz Armin , Schweda Frank , Todorov Vladimir , Wagner Charlotte
Published: April 2010

The protease renin is the key enzyme of the renin-angiotensin-aldosterone cascade, which is relevant under both physiological and pathophysiological settings. The kidney is the only organ capable of releasing enzymatically active renin. Although the characteristic juxtaglomerular position is the best known site of renin generation, renin-producing cells in the kidney can vary in number and localization. (Pro)renin gene transcription in these cells is controlled by a number of transcription factors, among which CREB is the best characterized. Pro-renin is stored in vesicles, activated to renin, and then released upon demand. The release of renin is under the control of the cAMP (stimulatory) and Ca2+(inhibitory) signaling pathways. Meanwhile, a great number of intrarenally generated or systemically acting factors have been identified that control the renin secretion directly at the level of renin-producing cells, by activating either of the signaling pathways mentioned above. The broad spectrum of biological actions of (pro)renin is mediated by receptors for (pro)renin, angiotensin II and angiotensin-( 1 – 7 ).
The N-Terminal Domain of Y-Box Binding Protein-1 Induces Cell Cycle Arrest in G2/M Phase by Binding to Cyclin D1
Authors: Khandelwal Payal , Padala Mythili K. , Cox John , Guntaka Ramareddy V.
Published: April 2010

Y-box binding protein YB-1 is a multifunctional protein involved in cell proliferation, regulation of transcription and translation. Our previous study indicated that disruption of one allele of Chk-YB-1b gene in DT-40 cells resulted in major defects in the cell cycle. The abnormalities seen in heterozygous mutants could be attributed to a dominant negative effect exerted by the disrupted YB-1 allele product. To test this hypothesis the N-terminal sequence of the YB-1 was fused with the third helix of antennapedia and the green fluorescent protein. These purified fusion proteins were introduced into rat hepatoma cells and their effect on cell proliferation was studied. Results indicate that the N-terminal 77 amino acid domain of the YB-1 protein induced the cells to arrest in G2/M phase of the cell cycle and undergo apoptosis. Additional deletion analysis indicated that as few as 26 amino acids of the N-terminus of YB-1 can cause these phenotypic changes. We further demonstrated that this N-terminal 77 amino acid domain of YB-1 sequesters cyclin D1 in the cytoplasm of cells at G2/M phase of cell cycle. We conclude that the N-terminal domain of YB-1 plays a major role in cell cycle progression through G2/M phase of cell cycle.
Office Hysteroscopy for Infertility: A Series of 557 Consecutive Cases
Authors: Koskas Martin , Mergui Jean-Luc , Yazbeck Chadi , Uzan Serge , Nizard Jacky
Published: April 2010

Objective. To study incidence of abnormal hysteroscopic findings according to age. Methods. We retrospectively studied 557 consecutive office hysteroscopies in patients referred for incapacity to conceive lasting at least 1 year or prior to in vitro fertilization. Rates of abnormal findings were reviewed according to age. Results. In 219 cases, hysteroscopy showed an abnormality and more than a third of our population had abnormal findings that could be related to infertility. Rates of abnormal findings ranged from 30% at 30 years to more than 60% after 42 years. Risk of abnormal finding was multiplied by a factor of 1.5 every 5 years. Conclusion. Our data are an additional argument to propose office hysteroscopy as part of first‐line exams in infertile woman, regardless of age.
Mass Production of LiFePO4/C Powders by Large Type Spray Pyrolysis Apparatus and Its Application to Cathode for Lithium Ion Battery
Authors: Akao Shinsuke , Yamada Motofumi , Kodera Takayuki , Ogihara Takashi
Published: April 2010

Spherical LiFePO4/C powders were successfully produced at a rate of 100 g/h using a large type spray pyrolysis apparatus. Organic compounds such as citric acid and sucrose were used as carbon sources. Scanning electron microscopy observation showed that they had a spherical morphology with nonaggregation. X-ray diffraction analysis revealed that the olivine phase was obtained by heating at600∘Cunder argon (95%)/hydrogen (5%) atmosphere. The chemical composition of LiFePO4/C powders was in good agreement with that of the starting solution. Electrochemical measurement revealed that the use of citric acid was most effective in ensuring a high rechargeable capacity and cycle stability. The rechargeable capacity of the LiFePO4/C cathode obtained using citric acid was 155 mAh/g at a discharge rate of 1 C. Because of the good discharge capacity of the LiFePO4/C cathode, it exhibited excellent cycle stability after 100 cycles at each discharge rate. Moreover, this high cycle stability of the LiFePO4/C cathode was maintained even at50∘C.
Modified Variational Iteration Method for Free‐Convective Boundary‐Layer Equation Using Padé Approximation
Authors: Mohyud-Din Syed Tauseef , Yildirim Ahmet , Anıl Sezer Sefa , Usman Muhammad
Published: April 2010

This paper is devoted to the study of a free‐convective boundary‐layer flow modeled by a system of nonlinear ordinary differential equations. We apply a modified variational iteration method (MVIM) coupled with He′s polynomials and Padé approximation to solve free‐convective boundary‐layer equation. It is observed that the combination of MVIM and the Padé approximation improves the accuracy and enlarges the convergence domain.
Titin-Isoform Dependence of Titin-Actin Interaction and Its Regulation by S100A1/Ca2+in Skinned Myocardium
Authors: Fukushima Hideto , Chung Charles S. , Granzier Henk
Published: April 2010

Titin, also known as connectin, is a large filamentous protein that greatly contributes to passive myocardial stiffness. In vitro evidence suggests that one of titin's spring elements, the PEVK, interacts with actin and that this adds a viscous component to passive stiffness. Differential splicing of titin gives rise to the stiff N2B and more compliant N2BA isoforms. Here we studied the titin-isoform dependence of titin-actin interaction and studied the bovine left atrium (BLA) that expresses mainly N2BA titin, and the bovine left ventricle (BLV) that expresses a mixture of both N2B and N2BA isforms. For comparison we also studied mouse left ventricular (MLV) myocardium which expresses predominately N2B titin. Using the actin-severing protein gelsolin, we obtained evidence that titin-actin interaction contributes significantly to passive myocardial stiffness in all tissue types, but most in MLV, least in BLA, and an intermediate level in BLV. We also studied whether titin-actin interaction is regulated by S100A1/calcium and found that calcium alone or S100A1 alone did not alter passive stiffness, but that combined they significantly lowered stiffness. We propose that titin-actin interaction is a “viscous break” that is on during diastole and off during systole.
Mixed-Signal Parallel Compressive Spectrum Sensing for Cognitive Radios
Authors: Yu Zhuizhuan , Chen Xi , Hoyos Sebastian , Sadler Brian M. , Gong Jingxuan , Qian Chengliang
Published: April 2010

Wideband spectrum sensing for cognitive radios requires very demanding analog-to-digital conversion (ADC) speed and dynamic range. In this paper, a mixed-signal parallel compressive sensing architecture is developed to realize wideband spectrum sensing for cognitive radios at sub-Nqyuist rates by exploiting the sparsity in current frequency usage. Overlapping windowed integrators are used for analog basis expansion, that provides flexible filter nulls for clock leakage spur rejection. A low-speed experimental system, built with off-the-shelf components, is presented. The impact of circuit nonidealities is considered in detail, providing insight for a future integrated circuit implementation.
Asymptotic Principal Values and Regularization Methods for Correlation Functions with Reflective Boundary Conditions
Authors: Seriu Masafumi
Published: April 2010

We introduce a concept of asymptotic principal values which enables us to handle rigorously singular integrals of higher-order poles encountered in the computation of various quantities based
on correlation functions of a vacuum. Several theorems on asymptotic principal values are proved, and they are expected to become bases for investigating and developing some classes of regularization methods for singular integrals.
We make use of these theorems for analyzing mutual relations between some regularization methods,
including a method naturally derived from asymptotic principal values. It turns out that the
concept of asymptotic principal values and the theorems for them are quite useful in this type of
analysis, providing a suitable language to describe what is discarded and what is retained in each
regularization method.
Proteomic Characterization of Novel Alternative Splice Variant Proteins in Human Epidermal Growth Factor Receptor 2/neu–Induced Breast Cancers
Authors: Menon Rajasree , Omenn Gilbert S.
Published: April 2010

Multifaceted alternative splicing in cancer cells greatly diversifies protein structure independently of genome changes, but the characterization of cancer-associated splice variants is quite limited. In this study, we used mass spectrometric data to interrogate a custom-built database created with three-frame translations of mRNA sequences from Ensembl and ECgene to find alternative splice variant proteins. In mass spectrometric files from liquid chromatography tandem mass spectrometry (LC-MS/MS) analyses of normal mouse mammary glands or mammary tumors derived from conditional human epidermal growth factor receptor 2 (Her2)/neu transgenic mice, we identified a total of 608 alternative splice variants, of which peptides from 216 proteins were found only in the tumor sample. Among the 608 splice variants were 68 novel proteins that were not completely matched to any known protein sequence in mice, for which we found known functional motifs. Biological process enrichment analysis of the splice variants identified suggested the involvement of these proteins especially in cell motility and translation initiation. The cancer-associated differentially expressed splice variant proteins offer novel biomarker candidates that may function in breast cancer progression or metastasis. Cancer Res; 70(9); 3440–9. ©2010 AACR.
Id2 Promotes Tumor Cell Migration and Invasion through Transcriptional Repression of Semaphorin 3F
Authors: Coma Silvia , Amin Dhara N. , Shimizu Akio , Lasorella Anna , Iavarone Antonio , Klagsbrun Michael
Published: April 2010

Id proteins (Id1 to Id4) are helix-loop-helix transcription factors that promote metastasis. It was found that Semaphorin 3F (SEMA3F), a potent inhibitor of metastasis, was repressed by Id2. High metastatic human tumor cell lines had relatively high amounts of Id2 and low SEMA3F levels compared with their low metastatic counterparts. No correlation between metastatic potential and expression of the other Id family members was observed. Furthermore, ectopic expression of Id2 in low metastatic tumor cells downregulated SEMA3F and, as a consequence, enhanced their ability to migrate and invade, two requisite steps of metastasis in vivo. Id2 overexpression was driven by the c-myc oncoprotein. SEMA3F was a direct target gene of the E47/Id2 pathway. Two E-box sites, which bind E protein transcription factors including E47, were identified in the promoter region of the SEMA3F gene. E47 directly activated SEMA3F promoter activity and expression and promoted SEMA3F biological activities, including filamentous actin depolymerization, inactivation of RhoA, and inhibition of cell migration. Silencing of SEMA3F inhibited the E47-induced SEMA3F expression and biological activities, confirming that these E47-induced effects were SEMA3F dependent. E47 did not induce expression of the other members of the SEMA3 family. Id2, a dominant-negative inhibitor of E proteins, abrogated the E47-induced SEMA3F expression and biological activities. Thus, high metastatic tumor cells overexpress c-myc, leading to upregulation of Id2 expression; the aberrantly elevated amount of Id2 represses SEMA3F expression and, as a consequence, enhances the ability of tumor cells to migrate and invade. Cancer Res; 70(9); 3823–32. ©2010 AACR.
Prospective Study of the Association of Serum γ-Glutamyltransferase with Cervical Intraepithelial Neoplasia III and Invasive Cervical Cancer
Authors: Strasak Alexander M. , Goebel Georg , Concin Hans , Pfeiffer Ruth M. , Brant Larry J. , Nagel Gabriele , Oberaigner Willi , Concin Nicole , Diem Günter , Ruttmann Elfriede , Gruber-Moesenbacher Ulrike , Offner Felix , Pompella Alfonso , Pfeiffer Karl P. , Ulmer Hanno ,   the VHM&PP Study Group
Published: April 2010

Epidemiologic studies indicate that elevated levels of γ-glutamyltransferase (GGT), a key enzyme of glutathione metabolism, might be associated with increased cancer risk. Furthermore, preclinical studies support a role for GGT in tumor invasion and progression. However, the relationship between GGT and risks of cervical intraepithelial neoplasia III (CIN-III) and invasive cervical cancer (ICC) have not been evaluated. We investigated the association of enzymatically determined GGT in blood serum with subsequent incidence of CIN-III and ICC in a prospective population-based cohort of 92,843 women ages 18 to 95, of whom 79% had at least one gynecologic examination including Pap smear testing during follow-up. Cox regression was used to compute adjusted hazard ratios (HR) with 95% confidence intervals for the association of GGT with CIN-III and ICC. During median follow-up of 13.8 years, 702 CIN-III and 117 ICC diagnoses were observed. Compared with normal low GGT (<17.99 units/L), risk of ICC was significantly elevated for all other baseline GGT categories, with adjusted HRs of 2.31 (1.49–3.59) for normal high GGT (18.00–35.99 units/L), 2.76 (1.52–5.02) for elevated GGT (36.00–71.99 units/L), and 3.38 (1.63–7.00) for highly elevated GGT [>72.00 units/L; P trend < 0.0001, HR log unit increase 3.45 (1.92–6.19)]. In contrast, associations between GGT serum levels and CIN-III risk were not statistically significant in the main analysis. Exclusion of the first 2 or 5 years of follow-up did not change the results. Effects did not differ by age, body mass index, or socioeconomic status. Our findings implicate GGT in the progression of premalignant cervical lesions to invasive cancer. Cancer Res; 70(9); 3586–93. ©2010 AACR.
Somatic Hypermethylation of MSH2 Is a Frequent Event in Lynch Syndrome Colorectal Cancers
Authors: Nagasaka Takeshi , Rhees Jennifer , Kloor Matthias , Gebert Johannes , Naomoto Yoshio , Boland C. Richard , Goel Ajay
Published: April 2010

Heritable germline epimutations in MSH2 have been reported in a few Lynch syndrome families that lacked germline mutations in the MSH2 gene. It is not known whether somatic MSH2 methylation occurs in MSH2 mutation–positive Lynch syndrome subjects or sporadic colorectal cancers (CRC). Therefore, we determined the methylation status of the MSH2 gene in 268 CRC tissues, including 222 sporadic CRCs and 46 Lynch syndrome tumors that did not express MSH2. We also looked for microsatellite instability (MSI), germline mutations in the MSH2 and EpCAM genes, somatic mutations in BRAF and KRAS, and the CpG island methylator phenotype (CIMP). We observed that somatic MSH2 hypermethylation was present in 24% (11 of 46) of MSH2-deficient (presumed Lynch syndrome) tumors, whereas no evidence for MSH2 methylation existed in sporadic CRCs (MSI and microsatellite stable) or normal colonic tissues. Seven of 11 (63%) patients with MSH2 methylation harbored simultaneous pathogenic germline mutations in the MSH2 gene. Germline EpCAM deletions were present in three of four patients with MSH2 methylation but without pathogenic MSH2 germline mutations. The mean methylation scores at CIMP-related markers were significantly higher in Lynch syndrome tumors with MSH2 methylation than MSH2-unmethylated CRCs. In conclusion, our data provide evidence for frequent MSH2 hypermethylation in Lynch syndrome tumors with MSH2 deficiency. MSH2 methylation in this subset of individuals is somatic and may serve as the “second hit” at the wild-type allele. High levels of aberrant methylation at CIMP-related markers in MSH2-methylated tumors raise the possibility that MSH2 is a target susceptible to aberrant methylation in Lynch syndrome. Cancer Res; 70(8); 3098–108. ©2010 AACR.
CUDC-101, a Multitargeted Inhibitor of Histone Deacetylase, Epidermal Growth Factor Receptor, and Human Epidermal Growth Factor Receptor 2, Exerts Potent Anticancer Activity
Authors: Lai Cheng-Jung , Bao Rudi , Tao Xu , Wang Jing , Atoyan Ruzanna , Qu Hui , Wang Da-Gong , Yin Ling , Samson Maria , Forrester Jeffrey , Zifcak Brian , Xu Guang-Xin , DellaRocca Steven , Zhai Hai-Xiao , Cai Xiong , Munger William E. , Keegan Mitchell , Pepicelli Carmen V. , Qian Changgeng
Published: April 2010

Receptor tyrosine kinase inhibitors have recently become important therapeutics for a variety of cancers. However, due to the heterogeneous and dynamic nature of tumors, the effectiveness of these agents is often hindered by poor response rates and acquired drug resistance. To overcome these limitations, we created a novel small molecule, CUDC-101, which simultaneously inhibits histone deacetylase and the receptor kinases epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 (HER2) in cancer cells. Because of its integrated histone deacetylase inhibition, CUDC-101 synergistically blocked key regulators of EGFR/HER2 signaling pathways, also attenuating multiple compensatory pathways, such as AKT, HER3, and MET, which enable cancer cells to escape the effects of conventional EGFR/HER2 inhibitors. CUDC-101 displayed potent antiproliferative and proapoptotic activities against cultured and implanted tumor cells that are sensitive or resistant to several approved single-targeted drugs. Our results show that CUDC-101 has the potential to dramatically improve the treatment of heterogeneous and drug-resistant tumors that cannot be controlled with single-target agents. Further, they provide a framework to create individual small molecules that simultaneously antagonize multiple biochemically distinct oncogenic targets, suggesting a general paradigm to surpass conventional, single-target cancer therapeutics. Cancer Res; 70(9); 3647–56. ©2010 AACR.
Tumor Site–Specific Silencing of NF-κB p65 by Targeted Hollow Gold Nanosphere–Mediated Photothermal Transfection
Authors: Lu Wei , Zhang Guodong , Zhang Rui , Flores Leo G. , Huang Qian , Gelovani Juri G. , Li Chun
Published: April 2010

NF-κB transcription factor is a critical regulator of the expression of genes involved in tumor formation and progression. Successful RNA interference (RNAi) therapeutics targeting NF-κB is challenged by small interfering RNA (siRNA) delivery systems, which can render targeted in vivo delivery, efficient endolysosomal escape, and dynamic control over activation of RNAi. Here, we report near-IR (NIR) light–inducible NF-κB downregulation through folate receptor–targeted hollow gold nanospheres carrying siRNA recognizing NF-κB p65 subunit. Using micro–positron emission tomography/computed tomography imaging, the targeted nanoconstructs exhibited significantly higher tumor uptake in nude mice bearing HeLa cervical cancer xenografts than nontargeted nanoparticles following i.v. administration. Mediated by hollow gold nanospheres, controllable cytoplasmic delivery of siRNA was obtained on NIR light irradiation through photothermal effect. Efficient downregulation of NF-κB p65 was achieved only in tumors irradiated with NIR light but not in nonirradiated tumors grown in the same mice. Liver, spleen, kidney, and lung were not affected by the treatments, in spite of significant uptake of the siRNA nanoparticles in these organs. We term this mode of action “photothermal transfection.” Combined treatments with p65 siRNA photothermal transfection and irinotecan caused substantially enhanced tumor apoptosis and significant tumor growth delay compared with other treatment regimens. Therefore, photothermal transfection of NF-κB p65 siRNA could effectively sensitize the tumor to chemotherapeutic agents. Because NIR light can penetrate the skin and be delivered with high spatiotemporal control, therapeutic RNAi may benefit from this novel transfection strategy while avoiding unwanted side effect. Cancer Res; 70(8); 3177–88. ©2010 AACR.
Mammalian Target of Rapamycin Activator RHEB Is Frequently Overexpressed in Human Carcinomas and Is Critical and Sufficient for Skin Epithelial Carcinogenesis
Authors: Lu Zhi Hong , Shvartsman Mark B. , Lee Andrew Y. , Shao Jenny M. , Murray Mollianne M. , Kladney Raleigh D. , Fan Dong , Krajewski Stan , Chiang Gary G. , Mills Gordon B. , Arbeit Jeffrey M.
Published: April 2010

Small GTPase Ras homologue enriched in brain (RHEB) binds and activates the key metabolic regulator mTORC1, which has an important role in cancer cells, but the role of RHEB in cancer pathogenesis has not been shown. By performing a meta-analysis of published cancer cytogenetic and transcriptome databases, we defined a gain of chromosome 7q36.1-q36.3 containing the RHEB locus, an overexpression of RHEB mRNA in several different carcinoma histotypes, and an association between RHEB upregulation and poor prognosis in breast and head and neck cancers. To model gain of function in epithelial malignancy, we targeted Rheb expression to murine basal keratinocytes of transgenic mice at levels similar to those that occur in human squamous cancer cell lines. Juvenile transgenic epidermis displayed constitutive mTORC1 pathway activation, elevated cyclin D1 protein, and diffuse skin hyperplasia. Skin tumors subsequently developed with concomitant stromal angio-inflammatory foci, evidencing induction of an epidermal hypoxia-inducible factor-1 transcriptional program, and paracrine feed-forward activation of the interleukin-6–signal transducer and activator of transcription 3 pathway. Rheb-induced tumor persistence and neoplastic molecular alterations were mTORC1 dependent. Rheb markedly sensitized transgenic epidermis to squamous carcinoma induction following a single dose of Ras-activating carcinogen 7,12-dimethylbenz(a)anthracene. Our findings offer direct evidence that RHEB facilitates multistage carcinogenesis through induction of multiple oncogenic mechanisms, perhaps contributing to the poor prognosis of patients with cancers overexpressing RHEB. Cancer Res; 70(8); 3287–98. ©2010 AACR.
Blueberry Phytochemicals Inhibit Growth and Metastatic Potential of MDA-MB-231 Breast Cancer Cells through Modulation of the Phosphatidylinositol 3-Kinase Pathway
Authors: Adams Lynn S. , Phung Sheryl , Yee Natalie , Seeram Navindra P. , Li Liya , Chen Shiuan
Published: April 2010

Dietary phytochemicals are known to exhibit a variety of anticarcinogenic properties. This study investigated the chemopreventive activity of blueberry extract in triple-negative breast cancer cell lines in vitro and in vivo. Blueberry decreased cell proliferation in HCC38, HCC1937, and MDA-MB-231 cells with no effect on the nontumorigenic MCF-10A cell line. Decreased metastatic potential of MDA-MB-231 cells by blueberry was shown through inhibition of cell motility using wound-healing assays and migration through a polyethylene terephthalate membrane. Blueberry treatment decreased the activity of matrix metalloproteinase-9 and the secretion of urokinase-type plasminogen activator while increasing tissue inhibitor of metalloproteinase-1 and plasminogen activator inhibitor-1 secretion in MDA-MB-231 conditioned medium as shown by Western blotting. Cell signaling pathways that control the expression/activation of these processes were investigated via Western blotting and reporter gene assay. Treatment with blueberry decreased phosphatidylinositol 3-kinase (PI3K)/AKT and NFκB activation in MDA-MB-231 cells, where protein kinase C and extracellular signal-regulated kinase (ERK) were not affected. In vivo, the efficacy of blueberry to inhibit triple-negative breast tumor growth was evaluated using the MDA-MB-231 xenograft model. Tumor weight and proliferation (Ki-67 expression) were decreased in blueberry-treated mice, where apoptosis (caspase-3 expression) was increased compared with controls. Immunohistochemical analysis of tumors from blueberry-fed mice showed decreased activation of AKT and p65 NFκB signaling proteins with no effect on the phosphorylation of ERK. These data illustrate the inhibitory effect of blueberry phytochemicals on the growth and metastatic potential of MDA-MB-231 cells through modulation of the PI3K/AKT/NFκB pathway. Cancer Res; 70(9); 3594–605. ©2010 AACR.
Piracy of Prostaglandin E2/EP Receptor–Mediated Signaling by Kaposi's Sarcoma-Associated Herpes Virus (HHV-8) for Latency Gene Expression: Strategy of a Successful Pathogen
Authors: George Paul Arun , Sharma-Walia Neelam , Kerur Nagaraj , White Carl , Chandran Bala
Published: April 2010

Kaposi's sarcoma-associated herpes virus (KSHV) is implicated in the pathogenesis of KS, a chronic inflammation-associated malignancy. Cyclooxygenase-2 (COX-2) and its metabolite prostaglandin E2 (PGE2), two pivotal proinflammatory/oncogeneic molecules, are proposed to play roles in the expression of major KSHV latency-associated nuclear antigen-1 (LANA-1). Microsomal PGE2 synthase, PGE2, and its receptors (EP1, EP2, EP3, and EP4) were detected in KS lesions with the distinct staining of EP2/EP4 in KS lesions. In latently infected endothelial TIVE-LTC cells, EP receptor antagonists downregulated LANA-1 expression as well as Ca2+, p-Src, p-PI3K, p-PKCζ/λ, and p-NF-κB, which are also some of the signal molecules proposed to be important in KS pathogenesis. Exogenous PGE2 and EP receptor agonists induced the LANA-1 promoter in 293 cells, and YY1, Sp1, Oct-1, Oct-6, C/EBP, and c-Jun transcription factors seem to be involved in this induction. PGE2/EP receptor-induced LANA-1 promoter activity was downregulated significantly by the inhibition of Ca2+, p-Src, p-PI3K, p-PKCζ/λ, and p-NF-κB. These findings implicate the inflammatory PGE2/EP receptors and the associated signal molecules in herpes virus latency and uncover a novel paradigm that shows the evolution of KSHV genome plasticity to use inflammatory response for its survival advantage of maintaining latent gene expression. These data also suggest that potential use of anti-COX-2 and anti-EP receptor therapy may not only ameliorate the chronic inflammation associated with KS but could also lead to elimination of the KSHV latent infection and the associated KS lesions. Cancer Res; 70(9); 3697–3708. ©2010 AACR.
Concomitant Tumor and Minor Histocompatibility Antigen–Specific Immunity Initiate Rejection and Maintain Remission from Established Spontaneous Solid Tumors
Authors: Hess Michelini Rodrigo , Freschi Massimo , Manzo Teresa , Jachetti Elena , Degl'Innocenti Elena , Grioni Matteo , Basso Veronica , Bonini Chiara , Simpson Elizabeth , Mondino Anna , Bellone Matteo
Published: April 2010

Nonmyeloablative hematopoietic cell transplantation can cure patients with hematologic malignancies but has reported limited success against solid tumors. This is possibly because of profound peripheral tolerance mechanisms and/or suboptimal tumor recognition by effector T lymphocytes. We report that in mice developing spontaneous prostate cancer, nonmyeloablative minor histocompatibility mismatched hematopoietic stem cell transplantation, and donor lymphocyte infusion of unmanipulated lymphocytes combined with posttransplant tumor-specific vaccination circumvents tumor-specific tolerance, allowing acute tumor rejection and the establishment of protective immunosurveillance. Although donor-derived tumor-specific T cells readily differentiated into effector cells and infiltrated the tumor soon after infusion, they were alone insufficient for tumor eradication, which instead required the concomitance of minor histocompatibiltiy antigen–specific CD8+ T-cell responses. The establishment of protective immunosurveillance was best induced by posttransplant tumor-specific vaccination. Hence, these results provide the proof of principle that tumor-specific T-cell responses have to be harnessed together with minor histocompatibility responses and sustained by posttransplant tumor-specific vaccination to improve the efficacy of allotransplantion for the cure of solid tumors. Cancer Res; 70(9); 3505–14. ©2010 AACR.
Telomere Length in Prospective and Retrospective Cancer Case-Control Studies
Authors: Pooley Karen A. , Sandhu Manjinder S. , Tyrer Jonathan , Shah Mitul , Driver Kristy E. , Luben Robert N. , Bingham Sheila A. , Ponder Bruce A.J. , Pharoah Paul D.P. , Khaw Kay-Tee , Easton Douglas F. , Dunning Alison M.
Published: April 2010

Previous studies have reported that shorter mean telomere length in lymphocytes was associated with increased susceptibility to common diseases of aging, and may be predictive of cancer risk. However, most analyses have examined retrospectively collected case-control studies. Mean telomere length was measured using high-throughput quantitative real-time PCR. Blood for DNA extraction was collected after cancer diagnosis in the East Anglian SEARCH Breast (2,243 cases and 2,181 controls) and SEARCH Colorectal (2,249 cases and 2,161 controls) studies. Prospective case-control studies were conducted for breast cancer (199 cases) and colorectal cancer (185 cases), nested within the EPIC-Norfolk cohort. Blood was collected at least 6 months prior to diagnosis, and was matched to DNA from two cancer-free controls per case. In the retrospective SEARCH studies, the age-adjusted odds ratios for shortest (Q4) versus longest (Q1) quartile of mean telomere length was 15.5 [95% confidence intervals (CI), 11.6–20.8; p-het = 5.7 × 10−75], with a “per quartile” P-trend = 2.1 × 10−80 for breast cancer; and 2.14 (95% CI, 1.77–2.59; p-het = 7.3 × 10−15), with a per quartile P-trend = 1.8 × 10−13 for colorectal cancer. In the prospective EPIC study, the comparable odds ratios (Q4 versus Q1) were 1.58 (95% CI, 0.75–3.31; p-het = 0.23) for breast cancer and 1.13 (95% CI, 0.54–2.36; p-het = 0.75) for colorectal cancer risk. Mean telomere length was shorter in retrospectively collected cases than in controls but the equivalent association was markedly weaker in the prospective studies. This suggests that telomere shortening largely occurs after diagnosis, and therefore, might not be of value in cancer prediction. Cancer Res; 70(8); 3170–6. ©2010 AACR.
Gemcitabine Sensitivity Can Be Induced in Pancreatic Cancer Cells through Modulation of miR-200 and miR-21 Expression by Curcumin or Its Analogue CDF
Authors: Ali Shadan , Ahmad Aamir , Banerjee Sanjeev , Padhye Subhash , Dominiak Kristin , Schaffert Jacqueline M. , Wang Zhiwei , Philip Philip A. , Sarkar Fazlul H.
Published: April 2010

Curcumin induces cancer cell growth arrest and apoptosis in vitro, but its poor bioavailability in vivo limits its antitumor efficacy. We have previously evaluated the bioavailability of novel analogues of curcumin compared with curcumin, and we found that the analogue CDF exhibited greater systemic and pancreatic tissue bioavailability. In this study, we evaluated the effects of CDF or curcumin alone or in combination with gemcitabine on cell viability and apoptosis in gemcitabine-sensitive and gemcitabine-resistant pancreatic cancer (PC) cell lines. Mechanistic investigations revealed a significant reduction in cell viability in CDF-treated cells compared with curcumin-treated cells, which were also associated with the induction of apoptosis, and these results were consistent with the downregulation of Akt, cyclooxygenase-2, prostaglandin E2, vascular endothelial growth factor, and NF-κB DNA binding activity. We have also documented attenuated expression of miR-200 and increased expression of miR-21 (a signature of tumor aggressiveness) in gemcitabine-resistant cells relative to gemcitabine-sensitive cells. Interestingly, CDF treatment upregulated miR-200 expression and downregulated the expression of miR-21, and the downregulation of miR-21 resulted in the induction of PTEN. These results prompt further interest in CDF as a drug modality to improve treatment outcome of patients diagnosed with PC as a result of its greater bioavailability in pancreatic tissue. Cancer Res; 70(9); 3606–17. ©2010 AACR.
Sleeping Beauty–Mediated Somatic Mutagenesis Implicates CSF1 in the Formation of High-Grade Astrocytomas
Authors: Bender Aaron M. , Collier Lara S. , Rodriguez Fausto J. , Tieu Christina , Larson Jon D. , Halder Chandralekha , Mahlum Eric , Kollmeyer Thomas M. , Akagi Keiko , Sarkar Gobinda , Largaespada David A. , Jenkins Robert B.
Published: April 2010

The Sleeping Beauty (SB) transposon system has been used as an insertional mutagenesis tool to identify novel cancer genes. To identify glioma-associated genes, we evaluated tumor formation in the brain tissue from 117 transgenic mice that had undergone constitutive SB-mediated transposition. Upon analysis, 21 samples (18%) contained neoplastic tissue with features of high-grade astrocytomas. These tumors expressed glial markers and were histologically similar to human glioma. Genomic DNA from SB-induced astrocytoma tissue was extracted and transposon insertion sites were identified. Insertions in the growth factor gene Csf1 were found in 13 of the 21 tumors (62%), clustered in introns 5 and 8. Using reverse transcription-PCR, we documented increased Csf1 RNAs in tumor versus adjacent normal tissue, with the identification of transposon-terminated Csf1 mRNAs in astrocytomas with SB insertions in intron 8. Analysis of human glioblastomas revealed increased levels of Csf1 RNA and protein. Together, these results indicate that SB-insertional mutagenesis can identify high-grade astrocytoma-associated genes and they imply an important role for CSF1 in the development of these tumors. Cancer Res; 70(9); 3557–65. ©2010 AACR.
Combined Functional Genome Survey of Therapeutic Targets for Hepatocellular Carcinoma
Authors: Satow Reiko , Shitashige Miki , Kanai Yae , Takeshita Fumitaka , Ojima Hidenori , Jigami Takafumi , Honda Kazufumi , Kosuge Tomoo , Ochiya Takahiro , Hirohashi Setsuo , Yamada Tesshi
Published: April 2010

Purpose: The outcome of patients with advanced hepatocellular carcinoma (HCC) has remained unsatisfactory. Patients with HCC suffer from chronic hepatitis or liver cirrhosis, and their reserve liver function is often limited.

Experimental Design: To develop new therapeutic agents that act specifically on HCC but interfere only minimally with residual liver function, we searched for genes that were upregulated in 20 cases of HCC [namely, discovery sets 1 (n = 10) and 2 (n = 10)] in comparison with corresponding nontumorous liver and a panel representing normal organs using high-density microarrays capable of detecting all exons in the human genome.

Results: Eleven transcripts whose expression was significantly increased in HCC were subjected to siRNA-based secondary screening of genes required for HCC cell proliferation as well as quantitative reverse transcription-PCR analysis [validation sets 1 (n = 20) and 2 (n = 44)] and immunohistochemistry (n = 19). We finally extracted four genes, AKR1B10, HCAP-G, RRM2, and TPX2, as candidate therapeutic targets for HCC. siRNA-mediated knockdown of these candidate genes inhibited the proliferation of HCC cells and the growth of HCC xenografts transplanted into immunodeficient mice.

Conclusions: The four genes we identified were highly expressed in HCC, and HCC cells are highly dependent on these genes for proliferation. Although many important genes must have been overlooked, the selected genes were biologically relevant. The combination of genome-wide expression and functional screening described here is a rapid and comprehensive approach that could be applied in the identification of therapeutic targets in any type of human malignancy. Clin Cancer Res; 16(9); 2518–28. ©2010 AACR.
Crosstalk between Insulin/Insulin-like Growth Factor-1 Receptors and G Protein-Coupled Receptor Signaling Systems: A Novel Target for the Antidiabetic Drug Metformin in Pancreatic Cancer
Authors: Rozengurt Enrique , Sinnett-Smith James , Kisfalvi Krisztina
Published: April 2010

Insulin/insulin-like growth factor 1(IGF-1) receptors and G protein-coupled receptors (GPCR) signaling systems are implicated in autocrine-paracrine stimulation of a variety of malignancies, including ductal adenocarcinoma of the pancreas, one of the most lethal human diseases. Novel targets for pancreatic cancer therapy are urgently needed. We identified a crosstalk between insulin/IGF-1 receptors and GPCR signaling systems in pancreatic cancer cells, leading to enhanced signaling, DNA synthesis, and proliferation. Crosstalk between these signaling systems depends on mammalian target of rapamycin (mTOR) complex 1 (mTORC1). Metformin, the most widely used drug in the treatment of type 2 diabetes, activates AMP kinase (AMPK), which negatively regulates mTORC1. Recent results show that metformin-induced activation of AMPK disrupts crosstalk between insulin/IGF-1 receptor and GPCR signaling in pancreatic cancer cells and inhibits the growth of these cells in xenograft models. Given that insulin/IGF-1 and GPCRs are implicated in other malignancies, a similar crosstalk mechanism may be operative in other cancer cell types. Recent epidemiological studies linked administration of metformin with a reduced risk of pancreatic, breast, and prostate cancer in diabetic patients. We posit that crosstalk between insulin/IGF-1 receptor and GPCR signaling is a mechanism for promoting the development of certain types of cancer and a target for the prevention and therapy of these diseases via metformin administration. Clin Cancer Res; 16(9); 2505–11. ©2010 AACR.
Maintenance Therapy for Advanced Non-small Cell Lung Cancer: Current Status, Controversies, and Emerging Consensus
Authors: Owonikoko Taofeek K. , Ramalingam Suresh S. , Belani Chandra P.
Published: April 2010

Maintenance therapy refers to the use of an active therapeutic agent for extended duration following frontline induction therapy for patients with advanced stage non-small cell lung cancer (NSCLC). Multiple clinical trials reported within the last few months have shown a beneficial role for maintenance therapy especially in select patient groups characterized by histology and/or molecular profile. With the recent approval by the U.S. Food and Drug Administration and European Medicines Agency of pemetrexed for maintenance therapy, a new treatment paradigm has been introduced to the treatment of NSCLC. This article reviews recent data with maintenance therapy in advanced NSCLC and discusses the implications for routine patient care and future drug development. Clin Cancer Res; 16(9); 2496–504. ©2010 AACR.
Sulforaphane, a Dietary Component of Broccoli/Broccoli Sprouts, Inhibits Breast Cancer Stem Cells
Authors: Li Yanyan , Zhang Tao , Korkaya Hasan , Liu Suling , Lee Hsiu-Fang , Newman Bryan , Yu Yanke , Clouthier Shawn G. , Schwartz Steven J. , Wicha Max S. , Sun Duxin
Published: April 2010

Purpose: The existence of cancer stem cells (CSCs) in breast cancer has profound implications for cancer prevention. In this study, we evaluated sulforaphane, a natural compound derived from broccoli/broccoli sprouts, for its efficacy to inhibit breast CSCs and its potential mechanism.

Experimental Design: Aldefluor assay and mammosphere formation assay were used to evaluate the effect of sulforaphane on breast CSCs in vitro. A nonobese diabetic/severe combined immunodeficient xenograft model was used to determine whether sulforaphane could target breast CSCs in vivo, as assessed by Aldefluor assay, and tumor growth upon cell reimplantation in secondary mice. The potential mechanism was investigated using Western blotting analysis and β-catenin reporter assay.

Results: Sulforaphane (1-5 μmol/L) decreased aldehyde dehydrogenase–positive cell population by 65% to 80% in human breast cancer cells (P < 0.01) and reduced the size and number of primary mammospheres by 8- to 125-fold and 45% to 75% (P < 0.01), respectively. Daily injection with 50 mg/kg sulforaphane for 2 weeks reduced aldehyde dehydrogenase–positive cells by >50% in nonobese diabetic/severe combined immunodeficient xenograft tumors (P = 0.003). Sulforaphane eliminated breast CSCs in vivo, thereby abrogating tumor growth after the reimplantation of primary tumor cells into the secondary mice (P < 0.01). Western blotting analysis and β-catenin reporter assay showed that sulforaphane downregulated the Wnt/β-catenin self-renewal pathway.

Conclusions: Sulforaphane inhibits breast CSCs and downregulates the Wnt/β-catenin self-renewal pathway. These findings support the use of sulforaphane for the chemoprevention of breast cancer stem cells and warrant further clinical evaluation. Clin Cancer Res; 16(9); 2580–90. ©2010 AACR.