bluuebunny/crossref_metadata_2025 huggingface dataset:
Deformation within part of a major crustal shear zone, Parry Sound, Ontario: structure and kinematics
Authors: White Joseph Clancy , Flagler Patricia A.
Published: May 2009

Deformation within part of the Parry Sound shear zone (PSSZ), in the southwestern Grenville structural province, has been examined at the transition from mylonitized gabbroic anorthosite and orthogneiss within the body of the PSSZ to retrograde granulites in the immediate hanging wall. Detailed structural analysis shows a framework of internally deformed imbricate domains within the hanging-wall granulites that are truncated by a major dislocation within the PSSZ mylonites. Deformation geometries within discrete hanging-wall domains and the PSSZ exhibit strong similarities ascribable to a common deformation cycle that typically preserves three generations of overprinting structures. This cycle comprises (i) formation of shear-induced recumbent isoclinal folds and stretching lineations with concomitant transposition of compositional layering; (ii) rotation of fold axes during noncoaxial shear into parallelism with the stretching lineation and formation of sheath folds; and (iii) refolding about axes nearly orthogonal to the stretching lineations, followed by another period of transposition and reorientation during continued shear. The periodicity of this deformation is specifically documented by the generation, dispersion, and reorientation of fold axes and stretching lineations toward an end orientation consistent with northwest overthrust transport. This cycle reconciles the coexistence of upright structures with large subhorizontal displacements within a regime of progressive noncoaxial shear, where there is a near orthogonality between overprinted finite strain elements, which reflects the stability of the kinematic framework at both local and regional scales.
Crustal-scale ramp in a Middle Proterozoic orogen, Northwest Territories, Canada
Authors: Clark Elizabeth A. , Cook Frederick A.
Published: May 2009

Deep crustal seismic data from the Fort Goodhope area, Northwest Territories, Canada, image crustal structures associated with Middle Proterozoic compressional deformation. These include 10–20 km wide antiforms and thrust faults that lie above a west-dipping crustal-scale ramp with at least 10 km of vertical relief. The deformation is interpreted as being associated with structures observed in the subsurface to the east and may be partly coeval with deformation originally detected in outcrop in the Rackla Range of the Wernecke Mountains. These new deep crustal profiles, coupled with data to the east that delineate structures to 15 km depth, reveal large-scale similarity between this Middle Proterozoic orogen and many Phanerozoic compressional orogens.
Paléogéographie des algues calcaires marines carbonifères
Authors: Mamet Bernard L.
Published: May 2009

Three marine algal microfloral realms are recognized in the Carboniferous: (i) a Tethyan flora with numerous Dasycladales and high endemism, (ii) a North American flora with some Dasycladales and fairly low endemism, and (iii) an Arctic flora composed of Dasycladales in low numbers and with cosmopolitan assemblages. These three phytochores are interconnected by a high number of "cosmopolitan" genera and species. However "transatlantic" exchanges are limited. The floras of the American exotic terranes (Peratrovich type) have some tethyan affinities but are basically cosmopolitan.
Increased AS160 phosphorylation, but not TBC1D1 phosphorylation, with increased postexercise insulin sensitivity in rat skeletal muscle
Authors: Funai Katsuhiko , Schweitzer George G. , Sharma Naveen , Kanzaki Makoto , Cartee Gregory D.
Published: May 2009

A single exercise bout can increase insulin-independent glucose transport immediately postexercise and insulin-dependent glucose transport (GT) for several hours postexercise. Akt substrate of 160 kDa (AS160) and TBC1D1 are paralog Rab GTPase-activating proteins that have been proposed to contribute to these exercise effects. Previous research demonstrated greater AS160 and Akt threonine phosphorylation in rat skeletal muscle at 3–4 h postexercise concomitant with enhanced insulin-stimulated GT. To further probe whether these signaling events or TBC1D1 phosphorylation were important for the enhanced postexercise insulin-stimulated GT, male Wistar rats were studied using four experimental protocols (2-h swim exercise, differing with regard to timing of muscle sampling and whether food was provided postexercise) that were known to vary in their influence of insulin-independent and insulin-dependent GT postexercise. The results indicated that, in isolated rat epitrochlearis muscle, 1) elevated phosphorylation of AS160 (measured using anti-phospho-Akt substrate, PAS-AS160, and phosphospecific anti-Thr642-AS160, pThr642-AS160) consistently tracked with elevated insulin-stimulated GT; 2) PAS-TBC1D1 was not different from sedentary values at 3 or 27 h postexercise, when insulin sensitivity was increased; 3) insulin-stimulated Akt activity was not increased postexercise in muscles with increased insulin sensitivity; 4) PAS-TBC1D1 was increased immediately postexercise, when insulin-independent GT was elevated, and reversed at 3 and 27 h postexercise, when insulin-independent GT was also reversed; and 5) there was no significant effect of exercise or insulin on total abundance of AS160, TBC1D1, Akt, or GLUT4 protein with any of the protocols. The results are consistent with increased AS160 phosphorylation (PAS-AS160 or pThr642-AS160) but not increased PAS-TBC1D1 or Akt activity, which is important for increased postexercise insulin-stimulated GT in rat skeletal muscle. They also support the idea that increased TBC1D1 phosphorylation may play a role in the insulin-independent increase in GT postexercise.
Is “fat-induced” muscle insulin resistance rapidly reversible?
Authors: Han Dong-Ho , Hancock Chad , Jung Su-Ryun , Holloszy John O.
Published: May 2009

Elevated plasma free fatty acids (FFA) cause insulin resistance and are thought to play a key role in mediating insulin resistance in patients with the metabolic syndrome (MTS) and type 2 diabetes mellitus (DM). Two experimental models used to study the mechanisms responsible for insulin resistance in patients are high-fat diet-fed rodents and administration of triglycerides and heparin to raise plasma FFA. As evidence that insulin resistance in high-fat diet-fed rats is due to high FFA, it has been reported that the insulin resistance is rapidly reversed by an overnight fast, a high-glucose meal, and an exercise bout. If true, these findings would invalidate the high-fat diet-fed rodent as a model for MTS or type 2 DM, because insulin resistance is not rapidly reversed by these treatments in patients. The purpose of this study was to determine whether diet-induced insulin resistance is, in fact, rapidly reversible. Incubation of muscles in vitro rapidly reversed insulin resistance induced by administration of triglycerides and heparin, but not by a high-fat diet. An overnight fast and a high-glucose meal were followed by a large increase in insulin-stimulated muscle glucose transport. However, these are adaptive responses, rather than reversals of insulin resistance, because they also occurred in muscles of insulin-sensitive, chow-fed control rats. Our results show that insulin resistance induced by high FFA, i.e., Randle glucose-fatty acid cycle, is transient. In contrast, the insulin resistance induced by a high-fat diet does not reverse rapidly.
Role of caveolin-1 in thyroid phenotype, cell homeostasis, and hormone synthesis: in vivo study of caveolin-1 knockout mice
Authors: Senou Maximin , Costa Maria José , Massart Claude , Thimmesch Matthieu , Khalifa Céline , Poncin Sylvie , Boucquey Marie , Gérard Anne-Catherine , Audinot Jean-Nicolas , Dessy Chantal , Ruf Jean , Feron Olivier , Devuyst Olivier , Guiot Yves , Dumont Jacques Emile , Van Sande Jacqueline , Many Marie-Christine
Published: May 2009

In human thyroid, caveolin-1 is localized at the apex of thyrocytes, but its role there remains unknown. Using immunohistochemistry,127I imaging, transmission electron microscopy, immunogold electron microscopy, and quantification of H2O2, we found that in caveolin-1 knockout mice thyroid cell homeostasis was disrupted, with evidence of oxidative stress, cell damage, and apoptosis. An even more striking phenotype was the absence of thyroglobulin and iodine in one-half of the follicular lumina and their presence in the cytosol, suggesting that the iodide organification and binding to thyroglobulin were intracellular rather than at the apical membrane/extracellular colloid interface. The latter abnormality may be secondary to the observed mislocalization of the thyroid hormone synthesis machinery (dual oxidases, thyroperoxidase) in the cytosol. Nevertheless, the overall uptake of radioiodide, its organification, and secretion as thyroid hormones were comparable to those of wild-type mice, suggesting adequate compensation by the normal TSH retrocontrol. Accordingly, the levels of free thyroxine and TSH were normal. Only the levels of free triiodothyronine showed a slight decrease in caveolin-1 knockout mice. However, when TSH levels were increased through low-iodine chow and sodium perchlorate, the induced goiter was more prominent in caveolin-1 knockout mice. We conclude that caveolin-1 plays a role in proper thyroid hormone synthesis as well as in cell number homeostasis. Our study demonstrates for the first time a physiological function of caveolin-1 in the thyroid gland. Because the expression and subcellular localization of caveolin-1 were similar between normal human and murine thyroids, our findings in caveolin-1 knockout mice may have direct relevance to the human counterpart.
The action of leptin in the ventral tegmental area to decrease food intake is dependent on Jak-2 signaling
Authors: Morton Gregory J. , Blevins James E. , Kim Francis , Matsen Miles , Figlewicz Dianne P.
Published: May 2009

Recent evidence suggests that leptin reduces food intake via actions in the brain circuitry of food reward, such as the ventral tegmental area (VTA), as leptin receptors are present in the VTA, and leptin injection in the VTA reduces food intake. In the hypothalamus, leptin-induced anorexia requires signaling via Janus kinase-signal transducer and activator of transcription (Jak-STAT), insulin receptor substrate (IRS)-phosphatidylinositol 3-kinase (PI 3-kinase), and mammalian target of rapamycin (mTOR). In this study, we determined whether leptin activates each of these signal transduction pathways in the VTA and whether these signaling pathways are required for VTA-leptin induced anorexia. Here, we show that pSTAT3-Tyr705, a marker of leptin activation, was induced in a midbrain region containing the VTA and substantia nigra following either intracerebroventricular leptin or direct administration of leptin to the VTA, but these interventions failed to increase levels of either pAKT-Ser473 or phospho-p70S6K-Thr389, markers of IRS-PI 3-kinase and mTOR signaling, respectively. Moreover, the effect of intra-VTA leptin administration to reduce 4- and 20-h food intake and 20-h body weight was blocked by an inhibitor of Jak-2, at a dose that had no effect on food intake or body weight by itself, but not by local inhibition of either PI 3-kinase (LY-294002) or mTOR (rapamycin) in this timeframe. Taken together, these data support the hypothesis that leptin signaling in the VTA is involved in the regulation of energy balance, but, in contrast to the leptin signaling in the hypothalamus, these effects are mediated predominantly via Jak-2 signaling rather than via the IRS-PI 3-kinase or mTOR signaling pathway.
Parietal Reach Region Encodes Reach Depth Using Retinal Disparity and Vergence Angle Signals
Authors: Bhattacharyya Rajan , Musallam Sam , Andersen Richard A.
Published: May 2009

Performing a visually guided reach requires the ability to perceive the egocentric distance of a target in three-dimensional space. Previous studies have shown that the parietal reach region (PRR) encodes the two-dimensional location of frontoparallel targets in an eye-centered reference frame. To investigate how a reach target is represented in three dimensions, we recorded the spiking activity of PRR neurons from two rhesus macaques trained to fixate and perform memory reaches to targets at different depths. Reach and fixation targets were configured to explore whether neural activity directly reflects egocentric distance as the amplitude of the required motor command, which is the absolute depth of the target, or rather the relative depth of the target with reference to fixation depth. We show that planning activity in PRR represents the depth of the reach target as a function of disparity and fixation depth, the spatial parameters important for encoding the depth of a reach goal in an eye centered reference frame. The strength of modulation by disparity is maintained across fixation depth. Fixation depth gain modulates disparity tuning while preserving the location of peak tuning features in PRR neurons. The results show that individual PRR neurons code depth with respect to the fixation point, that is, in eye centered coordinates. However, because the activity is gain modulated by vergence angle, the absolute depth can be decoded from the population activity.
Comparison of Time–Frequency Responses and the Event-Related Potential to Auditory Speech Stimuli in Human Cortex
Authors: Edwards Erik , Soltani Maryam , Kim Won , Dalal Sarang S. , Nagarajan Srikantan S. , Berger Mitchel S. , Knight Robert T.
Published: May 2009

We recorded the electrocorticogram directly from the exposed cortical surface of awake neurosurgical patients during the presentation of auditory syllable stimuli. All patients were unanesthetized as part of a language-mapping procedure for subsequent left-hemisphere tumor resection. Time–frequency analyses showed significant high-gamma (γhigh: 70–160 Hz) responses from the left superior temporal gyrus, but no reliable response from the left inferior frontal gyrus. Alpha suppression (α: 7–14 Hz) and event-related potential responses exhibited a more widespread topography. Across electrodes, the α suppression from 200 to 450 ms correlated with the preceding (50–200 ms) γhigh increase. The results are discussed in terms of the different physiological origins of these electrocortical signals.
Temporal Information Can Influence Spatial Localization
Authors: Maij Femke , Brenner Eli , Smeets Jeroen B. J.
Published: May 2009

To localize objects relative to ourselves, we need to combine various sensory and motor signals. When these signals change abruptly, as information about eye orientation does during saccades, small differences in latency between the signals could introduce localization errors. We examine whether independent temporal information can influence such errors. We asked participants to follow a randomly jumping dot with their eyes and to point at flashes that occurred near the time they made saccades. Such flashes are mislocalized. We presented a tone at different times relative to the flash. We found that the flash was mislocalized as if it had occurred closer in time to the tone. This demonstrates that temporal information is taken into consideration when combining sensory information streams for localization.
Muscle expression of genes associated with inflammation, growth, and remodeling is strongly correlated in older adults with resistance training outcomes
Authors: Dennis Richard A. , Zhu Haiyan , Kortebein Patrick M. , Bush Heather M. , Harvey Jonathan F. , Sullivan Dennis H. , Peterson Charlotte A.
Published: May 2009

A group ( n = 8) of healthy older (68 ± 6 yr) adults participated in a 36-session progressive resistance exercise training program targeting the thigh muscles to determine the relationship between muscle gene expression and gains in muscle size and strength. Biopsies were obtained from the vastus lateralis at baseline 72 h after an acute bout of exercise and 72 h after completion of the training program. Training increased thigh muscle size (7%) and strength for the three exercises performed: knee extension (30%) and curl (28%) and leg press (20%). We quantified 18 transcripts encoding factors that function in inflammation, growth, and muscle remodeling that were demonstrated previously to be regulated by aging and acute exercise. The gain in extension strength and muscle size showed a high number of significant correlations with gene expression. These gains were most strongly correlated ( P ≤ 0.003, R ≥ 0.89) with the baseline mRNA levels for insulin-like growth factor-1, matrix metalloproteinase-2 and its inhibitor TIMP1, and ciliary neurotrophic factor. Moreover, strength gains were inversely correlated with the change in these mRNA levels after training ( P ≤ 0.002 and R ≤ −0.90). Changes in gene expression after acute exercise were not associated with training outcomes. These results suggest that higher baseline expression for key genes in muscle conveys an adaptive advantage for certain older adults. Individuals with lower baseline expression of these genes show less adaptation to exercise despite increased gene expression in response to training. These genes hold promise as useful predictors of training outcomes that could be used to design more effective exercise regimens for maintaining muscle function in older adults.
Methylation ofTFPI2in Stool DNA: A Potential Novel Biomarker for the Detection of Colorectal Cancer
Authors: Glöckner Sabine C. , Dhir Mashaal , Yi Joo Mi , McGarvey Kelly E. , Van Neste Leander , Louwagie Joost , Chan Timothy A. , Kleeberger Wolfram , de Bruïne Adriaan P. , Smits Kim M. , Khalid-de Bakker Carolina A.J. , Jonkers Daisy M.A.E. , Stockbrügger Reinhold W. , Meijer Gerrit A. , Oort Frank A. , Iacobuzio-Donahue Christine , Bierau Katja , Herman James G. , Baylin Stephen B. , Van Engeland Manon , Schuebel Kornel E. , Ahuja Nita
Published: May 2009

We have used a gene expression array–based strategy to identify the methylation of tissue factor pathway inhibitor 2 (TFPI2), a potential tumor suppressor gene, as a frequent event in human colorectal cancers (CRC). TFPI2 belongs to the recently described group of embryonic cell Polycomb group (PcG)–marked genes that may be predisposed to aberrant DNA methylation in early stages of colorectal carcinogenesis. Aberrant methylation of TFPI2 was detected in almost all CRC adenomas (97%, n = 56) and stages I to IV CRCs (99%, n = 115). We further explored the potential of TFPI2 as a biomarker for the early detection of CRC using stool DNA–based assays in patients with nonmetastatic CRC and average-risk noncancer controls who were candidates for screening. TFPI2 methylation was detected in stool DNA from stage I to III CRC patients with a sensitivity of 76% to 89% and a specificity of 79% to 93%. Detection of TFPI2 methylation in stool DNA may act as a useful adjunct to the noninvasive strategies for screening of CRCs in the future. [Cancer Res 2009;69(11):4691–9]
Chemical Genomics Identifies the Unfolded Protein Response as a Target for Selective Cancer Cell Killing during Glucose Deprivation
Authors: Saito Sakae , Furuno Aki , Sakurai Junko , Sakamoto Asami , Park Hae-Ryong , Shin-ya Kazuo , Tsuruo Takashi , Tomida Akihiro
Published: May 2009

Glucose deprivation, a cell condition that occurs in solid tumors, activates the unfolded protein response (UPR). A key feature of the UPR is the transcription program activation, which allows the cell to survive under stress conditions. Here, we show that the UPR transcription program is disrupted by the antidiabetic biguanides metformin, buformin, and phenformin depending on cellular glucose availability. These drugs inhibit production of the UPR transcription activators XBP1 and ATF4 and induce massive cell death during glucose deprivation as did the antitumor macrocyclic compound versipelostatin. Gene expression profiling shows remarkable similarity in the modes of action of biguanides and versipelostatin determined by the broad range of glucose deprivation-inducible genes. Importantly, during glucose deprivation, most of the biguanide suppression genes overlap with the genes induced by tunicamycin, a chemical UPR inducer. Gene expression profiling also identifies drug-driven signatures as a tool for discovering pharmacologic UPR modulators. Our findings show that disrupting the UPR during glucose deprivation could be an attractive approach for selective cancer cell killing and could provide a chemical genomic basis for developing UPR-targeting drugs against solid tumors. [Cancer Res 2009;69(10):4225–34]
A Genetic Screen Identifies Topoisomerase 1 as a Regulator of Senescence
Authors: Humbert Nicolas , Martien Sébastien , Augert Arnaud , Da Costa Marco , Mauen Sébastien , Abbadie Corinne , de Launoit Yvan , Gil Jesús , Bernard David
Published: May 2009

Normal cell growth can be permanently blocked when cells enter a state known as senescence. This phenomenon can be triggered by various stresses, such as replicative exhaustion, oncogenic stimulation, or oxidative stress. Senescence prevents transmission of aberrant signals to daughter cells and thus prevents irreversible damage that could favor cancer development. To identify new genetic events controlling senescence, we have performed a loss-of-function genetic screen on normal human cells. We report that knockdown of topoisomerase I (Top1) results in an increased replicative potential associated with a decrease in senescence markers and a diminished DNA damage response. In addition, Top1 depletion also favors a bypass of oncogene-induced senescence. Conversely, Top1 constitutive expression induces growth arrest, the appearance of a senescence marker, and an activation of the DNA damage response. Altogether, these results reveal an unanticipated function of Top1 in regulating senescence. [Cancer Res 2009;69(10):4101–6]
Comparison of Primary Neuroblastoma Tumors and Derivative Early-Passage Cell Lines Using Genome-Wide Single Nucleotide Polymorphism Array Analysis
Authors: Volchenboum Samuel L. , Li Cheng , Li Shuli , Attiyeh Edward F. , Reynolds C. Patrick , Maris John M. , Look A. Thomas , George Rani E.
Published: May 2009

Stromal contamination is one of the major confounding factors in the analysis of solid tumor samples by single nucleotide polymorphism (SNP) arrays. As we propose to use genome-wide SNP microarray analysis as a diagnostic platform for neuroblastoma, the sensitivity, specificity, and accuracy of these studies must be optimized. To investigate the effects of stromal contamination, we derived early-passage cell lines from nine primary tumors and compared their genomic signature with that of the primary tumors using 100K SNP arrays. The average concordance between tumor and cell line for raw loss of heterozygosity (LOH) calls was 96% (range, 91–99%) and for raw copy number alterations, 71% (range, 43–87%). In general, there were a larger number of LOH events identified in the cell lines compared with the matched tumor samples (mean increase, 3.2% ± 1.9%). We have developed an algorithm that shows that the presence of stroma contributes to under-reporting of LOH and copy number loss. Notable findings in this sample set were uniparental disomy of chromosome arms 11p, 1q, 14q, and 15q and a novel area of amplification on chromosome band 11p15. Our analysis shows that LOH was identified significantly more often in derived cell lines compared with the original tumor samples. Although these may in part be due to clonal selection during adaptation to tissue culture, our study indicates that stromal contamination may be a major contributing factor in underestimation of LOH and copy number loss events. [Cancer Res 2009;69(10):4143–9]
Characterization of a Naturally Occurring Breast Cancer Subset Enriched in Epithelial-to-Mesenchymal Transition and Stem Cell Characteristics
Authors: Hennessy Bryan T. , Gonzalez-Angulo Ana-Maria , Stemke-Hale Katherine , Gilcrease Michael Z. , Krishnamurthy Savitri , Lee Ju-Seog , Fridlyand Jane , Sahin Aysegul , Agarwal Roshan , Joy Corwin , Liu Wenbin , Stivers David , Baggerly Keith , Carey Mark , Lluch Ana , Monteagudo Carlos , He Xiaping , Weigman Victor , Fan Cheng , Palazzo Juan , Hortobagyi Gabriel N. , Nolden Laura K. , Wang Nicholas J. , Valero Vicente , Gray Joe W. , Perou Charles M. , Mills Gordon B.
Published: May 2009

Metaplastic breast cancers (MBC) are aggressive, chemoresistant tumors characterized by lineage plasticity. To advance understanding of their pathogenesis and relatedness to other breast cancer subtypes, 28 MBCs were compared with common breast cancers using comparative genomic hybridization, transcriptional profiling, and reverse-phase protein arrays and by sequencing for common breast cancer mutations. MBCs showed unique DNA copy number aberrations compared with common breast cancers. PIK3CA mutations were detected in 9 of 19 MBCs (47.4%) versus 80 of 232 hormone receptor–positive cancers (34.5%; P = 0.32), 17 of 75 HER-2–positive samples (22.7%; P = 0.04), 20 of 240 basal-like cancers (8.3%; P < 0.0001), and 0 of 14 claudin-low tumors (P = 0.004). Of 7 phosphatidylinositol 3-kinase/AKT pathway phosphorylation sites, 6 were more highly phosphorylated in MBCs than in other breast tumor subtypes. The majority of MBCs displayed mRNA profiles different from those of the most common, including basal-like cancers. By transcriptional profiling, MBCs and the recently identified claudin-low breast cancer subset constitute related receptor-negative subgroups characterized by low expression of GATA3-regulated genes and of genes responsible for cell-cell adhesion with enrichment for markers linked to stem cell function and epithelial-to-mesenchymal transition (EMT). In contrast to other breast cancers, claudin-low tumors and most MBCs showed a significant similarity to a “tumorigenic” signature defined using CD44+/CD24− breast tumor–initiating stem cell–like cells. MBCs and claudin-low tumors are thus enriched in EMT and stem cell–like features, and may arise from an earlier, more chemoresistant breast epithelial precursor than basal-like or luminal cancers. PIK3CA mutations, EMT, and stem cell-like characteristics likely contribute to the poor outcomes of MBC and suggest novel therapeutic targets. [Cancer Res 2009;69(10):4116–24]
Up-regulation of L1CAM in Pancreatic Duct Cells Is Transforming Growth Factor β1– and Slug-Dependent: Role in Malignant Transformation of Pancreatic Cancer
Authors: Geismann Claudia , Morscheck Mascha , Koch Dorothee , Bergmann Frank , Ungefroren Hendrik , Arlt Alexander , Tsao Ming-Sound , Bachem Max G. , Altevogt Peter , Sipos Bence , Fölsch Ulrich R. , Schäfer Heiner , Müerköster Susanne Sebens
Published: May 2009

Pancreatic ductal adenocarcinoma (PDAC) is thought to originate from ductal structures, exhibiting strong desmoplastic reaction with stromal pancreatic myofibroblasts (PMF), which are supposed to drive PDAC tumorigenesis. Previously, we observed high expression of the adhesion molecule L1CAM (CD171) in PDAC cells accounting for chemoresistance. Thus, this study aimed to investigate whether PMFs are involved in the induction of tumoral L1CAM and whether this contributes to malignant transformation of pancreatic ductal cells and PDAC tumorigenesis. Immunohistochemistry of tissues from chronic pancreatitis specimens revealed considerable L1CAM expression in ductal structures surrounded by dense fibrotic tissue, whereas no L1CAM staining was seen in normal pancreatic tissues. Using the human pancreatic duct cell line H6c7, we show that coculture with PMFs led to a transforming growth factor-β1 (TGF-β1)–dependent up-regulation of L1CAM expression. Similarly, L1CAM expression increased in monocultured H6c7 cells after administration of exogenous TGF-β1. Both TGF-β1– and PMF-induced L1CAM expression were independent of Smad proteins but required c-Jun NH2-terminal kinase activation leading to the induction of the transcription factor Slug. Moreover, Slug interacted with the L1CAM promoter, and its knockdown abrogated the TGF-β1– and PMF-induced L1CAM expression. As a result of L1CAM expression, H6c7 cells acquired a chemoresistant and migratory phenotype. This mechanism of TGF-β1–induced L1CAM expression and the resulting phenotype could be verified in the TGF-β1–responsive PDAC cell lines Colo357 and Panc1. Our data provide new insights into the mechanisms of tumoral L1CAM induction and how PMFs contribute to malignant transformation of pancreatic duct cells early in PDAC tumorigenesis. [Cancer Res 2009;69(10):4517–26]
Cancer Vaccine Enhanced, Non–Tumor-Reactive CD8+ T Cells Exhibit a Distinct Molecular Program Associated with “Division Arrest Anergy”
Authors: Beyer Marc , Karbach Julia , Mallmann Michael R. , Zander Thomas , Eggle Daniela , Classen Sabine , Debey-Pascher Svenja , Famulok Michael , Jäger Elke , Schultze Joachim L.
Published: May 2009

Immune-mediated tumor rejection relies on fully functional T-cell responses and neutralization of an adverse tumor microenvironment. In clinical trials, we detected peptide-specific but non–tumor-reactive and therefore not fully functional CD8+ T cells post-vaccination against tumor antigens. Understanding the molecular mechanisms behind nontumor reactivity will be a prerequisite to overcome this CD8+ T-cell deviation. We report that these non–tumor-reactive CD8+ T cells are characterized by a molecular program associated with hallmarks of “division arrest anergy.” Non–tumor-reactive CD8+ T cells are characterized by coexpression of CD7, CD25, and CD69 as well as elevated levels of lckp505 and p27kip1. In vivo quantification revealed high prevalence of non–tumor-reactive CD8+ T cells with increased levels during cancer vaccination. Furthermore, their presence was associated with a trend toward shorter survival. Dynamics and frequencies of non–target-reactive CD8+ T cells need to be further addressed in context of therapeutic vaccine development in cancer, chronic infections, and autoimmune diseases. [Cancer Res 2009;69(10):4346–54]
3,3′-Diindolylmethane Enhances Taxotere-Induced Apoptosis in Hormone-Refractory Prostate Cancer Cells through Survivin Down-regulation
Authors: Rahman KM Wahidur , Banerjee Sanjeev , Ali Shadan , Ahmad Aamir , Wang Zhiwei , Kong Dejuan , Sakr Wael A.
Published: May 2009

Survivin, a member of inhibitor of apoptosis family, is associated with both prostate cancer progression and drug resistance. Therefore, we hypothesized that survivin may play a potentially important role in hormone-refractory prostate cancer (HRPC) and bone metastatic disease; thus, targeting of survivin signaling could enhance therapeutic efficacy in prostate cancer. 3,3′-Diindolylmethane (DIM) has been known to have cancer chemoprevention activity. However, no information is available regarding the down-regulation of survivin by DIM, which could result in the chemosensitization of HRPC cells to Taxotere-induced killing. We investigated the effect of DIM alone or in combination with Taxotere using LNCaP and C4-2B prostate cancer cells. We observed that DIM enhanced Taxotere-induced apoptotic death in both cell lines. These enhancing effects were related to a decrease in survivin expression as well as androgen receptor and nuclear factor-κB (NF-κB) DNA-binding activity. We also found that knockdown of survivin expression by small interfering RNA transfection increased DIM-induced cell growth inhibition and apoptosis, whereas overexpression of survivin by cDNA transfection abrogated DIM-induced cell growth inhibition and apoptosis in both prostate cancer cells. Importantly, luciferase assays showed a significant reduction of survivin-Luc and NF-κB-Luc activity in prostate cancer cells exposed to DIM and Taxotere. Furthermore, combination treatment significantly inhibited C4-2B bone tumor growth, and the results were correlated with the down-regulation of survivin. From these results, we conclude that inactivation of survivin by DIM enhanced the therapeutic efficacy of Taxotere in prostate cancer in general, which could be useful for the treatment of HRPC and metastatic prostate cancer. [Cancer Res 2009;69(10):4468–75]
A Three-Dimensional Osteogenic Tissue Model for the Study of Metastatic Tumor Cell Interactions with Bone
Authors: Mastro Andrea M. , Vogler Erwin A.
Published: May 2009

A specialized bioreactor based on the principle of simultaneous growth and dialysis permits growth of three-dimensional (3D), multiple-cell-layer osteogenic tissue from isolated osteoblasts over long, continuous-culture intervals (tested up to 10 months with no sign of necrosis). The resulting tissue recapitulates the stages of bone development observed in vivo, including phenotypic maturation of cobblestone-shaped osteoblasts into stellate-shaped osteocytes interconnected by many intercellular processes. Gene expression profiles parallel cell-morphologic changes with time, ultimately leading to increased expression of osteocyte-associated molecules such as E11, DMP1, and sclerostin. Contiguous, cm2-scale macroscopic mineral deposits that form within the bioreactor are consistent with bone hydroxyapatite. The simple to use bioreactor system provides an in vitro model that permits the study and manipulation of cancer cell interactions with bone tissue in real time. Metastatic human breast cancer cells, MDA-MB-231GFP, introduced into the model grow and colonize osteoblastic tissue in a manner reflecting various characteristics of pathologic tissue observed in the clinic. Specifically, MDA-MB-231GFP cells are observed to penetrate the thick extracellular matrix in which osteoblasts are embedded and to form chains reminiscent of "Indian files," described for infiltrating lobular or metaplastic breast carcinomas. Osteoblasts appear to be marshaled into a parallel alignment with cancer cells, followed by erosion of extracellular matrix structural integrity. Tissue degradation appears to be accompanied by increased expression of osteoblast inflammatory cytokines. [Cancer Res 2009;69(10):4097–100]
Complex Oncogenic Translocations with Gene Amplification Are Initiated by Specific DNA Breaks in Lymphocytes
Authors: Wright Sarah M. , Woo Yong H. , Alley Travis L. , Shirley Bobbi-Jo , Akeson Ellen C. , Snow Kathy J. , Maas Sarah A. , Elwell Rachel L. , Foreman Oded , Mills Kevin D.
Published: May 2009

Chromosomal instability is a hallmark of many tumor types. Complex chromosomal rearrangements with associated gene amplification, known as complicons, characterize many hematologic and solid cancers. Whereas chromosomal aberrations, including complicons, are useful diagnostic and prognostic cancer markers, their molecular origins are not known. Although accumulating evidence has implicated DNA double-strand break repair in suppression of oncogenic genome instability, the genomic elements required for chromosome rearrangements, especially complex lesions, have not been elucidated. Using a mouse model of B-lineage lymphoma, characterized by complicon formation involving the immunoglobulin heavy chain (Igh) locus and the c-myc oncogene, we have now investigated the requirement for specific genomic segments as donors for complex rearrangements. We now show that specific DNA double-strand breaks, occurring within a narrow segment of Igh, are necessary to initiate complicon formation. By contrast, neither specific DNA breaks nor the powerful intronic enhancer Eμ are required for complicon-independent oncogenesis. This study is the first to delineate mechanisms of complex versus simple instability and the first to identify specific chromosomal elements required for complex chromosomal aberrations. These findings will illuminate genomic cancer susceptibility and risk factors. [Cancer Res 2009;69(10):4454–60]
EGFRvIII and DNA Double-Strand Break Repair: A Molecular Mechanism for Radioresistance in Glioblastoma
Authors: Mukherjee Bipasha , McEllin Brian , Camacho Cristel V. , Tomimatsu Nozomi , Sirasanagandala Shyam , Nannepaga Suraj , Hatanpaa Kimmo J. , Mickey Bruce , Madden Christopher , Maher Elizabeth , Boothman David A. , Furnari Frank , Cavenee Webster K. , Bachoo Robert M. , Burma Sandeep
Published: May 2009

Glioblastoma multiforme (GBM) is the most lethal of brain tumors and is highly resistant to ionizing radiation (IR) and chemotherapy. Here, we report on a molecular mechanism by which a key glioma-specific mutation, epidermal growth factor receptor variant III (EGFRvIII), confers radiation resistance. Using Ink4a/Arf-deficient primary mouse astrocytes, primary astrocytes immortalized by p53/Rb suppression, as well as human U87 glioma cells, we show that EGFRvIII expression enhances clonogenic survival following IR. This enhanced radioresistance is due to accelerated repair of DNA double-strand breaks (DSB), the most lethal lesion inflicted by IR. The EGFR inhibitor gefitinib (Iressa) and the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 attenuate the rate of DSB repair. Importantly, expression of constitutively active, myristylated Akt-1 accelerates repair, implicating the PI3K/Akt-1 pathway in radioresistance. Most notably, EGFRvIII-expressing U87 glioma cells show elevated activation of a key DSB repair enzyme, DNA-dependent protein kinase catalytic subunit (DNA-PKcs). Enhanced radioresistance is abrogated by the DNA-PKcs–specific inhibitor NU7026, and EGFRvIII fails to confer radioresistance in DNA-PKcs–deficient cells. In vivo, orthotopic U87-EGFRvIII–derived tumors display faster rates of DSB repair following whole-brain radiotherapy compared with U87-derived tumors. Consequently, EGFRvIII-expressing tumors are radioresistant and continue to grow following whole-brain radiotherapy with little effect on overall survival. These in vitro and in vivo data support our hypothesis that EGFRvIII expression promotes DNA-PKcs activation and DSB repair, perhaps as a consequence of hyperactivated PI3K/Akt-1 signaling. Taken together, our results raise the possibility that EGFR and/or DNA-PKcs inhibition concurrent with radiation may be an effective therapeutic strategy for radiosensitizing high-grade gliomas. [Cancer Res 2009;69(10):4252–9]
Persistence of High-Grade Cervical Dysplasia and Cervical Cancer Requires the Continuous Expression of the Human Papillomavirus Type 16 E7 Oncogene
Authors: Jabbar Sean F. , Abrams Linda , Glick Adam , Lambert Paul F.
Published: May 2009

Several mucosotropic human papillomaviruses (HPV), including HPV type 16 (HPV-16), are etiologic agents of a subset of anogenital cancers and head and neck squamous cell carcinomas. In mice, HPV-16 E7 is the most potent of the papillomaviral oncogenes in the development of cervical disease. Furthermore, interfering specifically with the expression of E7 in HPV-positive cell lines derived from human cervical cancers inhibits their ability to proliferate, indicating that the expression of E7 is important in maintaining the transformed phenotype in vitro. To assess the temporal role of E7 in maintaining HPV-associated tumors and precancerous lesions in vivo, we generated Bi-L E7 transgenic mice that harbor a tetracycline-inducible transgene that expresses both HPV-16 E7 and firefly luciferase. When we crossed Bi-L E7 mice to a K5-tTA transgene-inducing line of mice, which expresses a tetracycline-responsive transactivator selectively in the stratified squamous epithelia, the resulting Bi-L E7/K5-tTA bitransgenic mice expressed E7 and luciferase in the skin and cervical epithelium, and doxycycline repressed this expression. Bitransgenic mice displayed several overt and acute epithelial phenotypes previously shown to be associated with the expression of E7, and these phenotypes were reversed on treatment with doxycycline. Repressing the expression of E7 caused the regression of high-grade cervical dysplasia and established cervical tumors, indicating that they depend on the continuous expression of E7 for their persistence. These results suggest that E7 is a relevant target not only for anticancer therapy but also for the treatment of HPV-positive dysplastic cervical lesions. [Cancer Res 2009;69(10):4407–14]
A Multicenter, Double-Blinded Validation Study of Methylation Biomarkers for Progression Prediction in Barrett's Esophagus
Authors: Jin Zhe , Cheng Yulan , Gu Wen , Zheng Yingye , Sato Fumiaki , Mori Yuriko , Olaru Alexandru V. , Paun Bogdan C. , Yang Jian , Kan Takatsugu , Ito Tetsuo , Hamilton James P. , Selaru Florin M. , Agarwal Rachana , David Stefan , Abraham John M. , Wolfsen Herbert C. , Wallace Michael B. , Shaheen Nicholas J. , Washington Kay , Wang Jean , Canto Marcia Irene , Bhattacharyya Achyut , Nelson Mark A. , Wagner Paul D. , Romero Yvonne , Wang Kenneth K. , Feng Ziding , Sampliner Richard E. , Meltzer Stephen J.
Published: May 2009

Esophageal adenocarcinoma risk in Barrett's esophagus (BE) is increased 30- to 125-fold versus the general population. Among all BE patients, however, neoplastic progression occurs only once per 200 patient-years. Molecular biomarkers are therefore needed to risk-stratify patients for more efficient surveillance endoscopy and to improve the early detection of progression. We therefore performed a retrospective, multicenter, double-blinded validation study of eight BE progression prediction methylation biomarkers. Progression or nonprogression were determined at 2 years (tier 1) and 4 years (tier 2). Methylation was assayed in 145 nonprogressors and 50 progressors using real-time quantitative methylation-specific PCR. Progressors were significantly older than nonprogressors (70.6 versus 62.5 years; P < 0.001). We evaluated a linear combination of the eight markers, using coefficients from a multivariate logistic regression analysis. Areas under the ROC curve (AUC) were high in the 2-year, 4-year, and combined data models (0.843, 0.829, and 0.840; P < 0.001, <0.001, and <0.001, respectively). In addition, even after rigorous overfitting correction, the incremental AUCs contributed by panels based on the 8 markers plus age versus age alone were substantial (Δ-AUC = 0.152, 0.114, and 0.118, respectively) in all 3 models. A methylation biomarker–based panel to predict neoplastic progression in BE has potential clinical value in improving both the efficiency of surveillance endoscopy and the early detection of neoplasia. [Cancer Res 2009;69(10):4112–5]
RIP1 Activates PI3K-Akt via a Dual Mechanism Involving NF-κB–Mediated Inhibition of the mTOR-S6K-IRS1 Negative Feedback Loop and Down-regulation of PTEN
Authors: Park Seongmi , Zhao Dawen , Hatanpaa Kimmo J. , Mickey Bruce E. , Saha Debabrata , Boothman David A. , Story Michael D. , Wong Eric T. , Burma Sandeep , Georgescu Maria-Magdalena , Rangnekar Vivek M. , Chauncey Sandili S. , Habib Amyn A.
Published: May 2009

Therapeutic inhibition of mammalian target of rapamycin (mTOR) in cancer is complicated by the existence of a negative feedback loop linking mTOR to the phosphatidylinositol 3-kinase (PI3K)-Akt pathway. Thus, mTOR inhibition by rapamycin or TSC1/2 results in increased PI3K-Akt activation. The death domain kinase receptor interacting protein 1 (RIP1) plays a key role in nuclear factor-κB (NF-κB) activation and also activates the PI3K-Akt pathway through unknown mechanisms. RIP1 has recently been found to be overexpressed in glioblastoma multiforme, the most common adult primary malignant brain tumor, but not in grade II to III glioma. Our data suggest that RIP1 activates PI3K-Akt using dual mechanisms by removing the two major brakes on PI3K-Akt activity. First, increased expression of RIP1 activates PI3K-Akt by interrupting the mTOR negative feedback loop. However, unlike other signals that regulate mTOR activity without affecting its level, RIP1 negatively regulates mTOR transcription via a NF-κB–dependent mechanism. The second mechanism used by RIP1 to activate PI3K-Akt is down-regulation of cellular PTEN levels, which appears to be independent of NF-κB activation. The clinical relevance of these findings is highlighted by the demonstration that RIP1 levels correlate with activation of Akt in glioblastoma multiforme. Thus, our study shows that RIP1 regulates key components of the PTEN-PI3K-Akt-mTOR pathway and elucidates a novel negative regulation of mTOR signaling at the transcriptional level by the NF-κB pathway. Our data suggest that the RIP1-NF-κB status of tumors may influence response to treatments targeting the PTEN-PI3K-mTOR signaling axis. [Cancer Res 2009;69(10):4107–11]
Meta-mining of Neuroblastoma and Neuroblast Gene Expression Profiles Reveals Candidate Therapeutic Compounds
Authors: De Preter Katleen , De Brouwer Sara , Van Maerken Tom , Pattyn Filip , Schramm Alexander , Eggert Angelika , Vandesompele Jo , Speleman Frank
Published: May 2009

Purpose: Neuroblastoma is a heterogeneous childhood tumor with poor survival outcome for the aggressive type despite intensive multimodal therapies. In this study, we aimed to identify new treatment options for neuroblastoma based on integrative genomic analysis.

Experimental Design: The Connectivity Map is a database comprising expression profiles in response to known therapeutic compounds. This renders it a useful tool in the search for potential therapeutic compounds based on comparison of gene expression profiles of diseased cells and a database of profiles in response to known therapeutic compounds. We have used this strategy in the search for new therapeutic molecules for neuroblastoma based on data of an integrative meta-analysis of gene copy number and expression profiles from 146 primary neuroblastoma tumors and normal fetal neuroblasts.

Results: In a first step, a 132-gene classifier was established that discriminates three major genomic neuroblastoma subgroups, reflecting inherent differences in gene expression between these subgroups. Subsequently, we screened the Connectivity Map database using gene lists generated by comparing expression profiles of fetal adrenal neuroblasts and the genomic subgroups of neuroblastomas. A putative therapeutic effect was predicted for several compounds of which six were empirically tested. A significant reduction in cell viability was shown for five of these molecules: 17-allylamino-geldanamycin, monorden, fluphenazine, trichostatin, and rapamycin.

Conclusions: This proof-of-principle study indicates that an integrative genomic meta-analysis approach with inclusion of neuroblast data enables the identification of promising compounds for treatment of children with neuroblastoma. Further studies are warranted to explore in detail the therapeutic potential of these compounds.
Tumoral Expression of TXR1 and TSP1 Predicts Overall Survival of Patients with Lung Adenocarcinoma Treated with First-line Docetaxel-Gemcitabine Regimen
Authors: Papadaki Chara , Mavroudis Dimitris , Trypaki Maria , Koutsopoulos Anastasios , Stathopoulos Efstathios , Hatzidaki Dora , Tsakalaki Eleftheria , Georgoulias Vassilis , Souglakos John
Published: May 2009

Purpose: In vitro data suggest that down-regulation of thrombospondin 1 (TSP1) expression from TXR1 is associated with resistance to taxane-based chemotherapy. The prognostic and predictive value of tumoral expression of both genes was evaluated in patients with lung adenocarcinoma treated with first-line docetaxel and gemcitabine.

Experimental Design: Tumor samples from 96 patients, with stage IIIB (with pleural effusion) or IV lung adenocarcinomas, were analyzed for TXR1 and TSP1 mRNA levels by quantitative real-time PCR, from microdissected cells derived from patients' primary tumors.

Results: The mRNA levels of the two genes were inversely correlated (Spearman's test = -0.49; P < 0.0001). Patients with low TXR1 mRNA levels experienced a longer median time to tumor progression (TTP; P < 0.0001) and median overall survival (mOS; P = 0.001) when compared with patients with high TXR1 expression. Patients with high TSP1 expression presented longer TTP (P = 0.002) and mOS (P < 0.0001) when compared with patients with low TSP1 expression. Moreover, patients with high TSP1 and low TXR1 expression (n = 36) presented higher prolonged TTP (P = 0.009) and mOS (P < 0.0001) compared with patients with high TXR1 and low TSP1 expression. Multivariate analysis showed that high TXR1/low TSP1 expression was an independent prognostic factor for decreased TTP (hazard ratio, 1.7; 95% confidence interval, 1.1-3.27; P = 0.016) and mOS (hazard ratio, 2.55; 95% confidence interval, 1.57-4.15; P < 0.0001).

Conclusion: These data confirm the in vitro model of TSP1 and TXR1 effect on taxane resistance in lung adenocarcinomas and merit further evaluation.