bluuebunny/crossref_metadata_2025 huggingface dataset:
INTERACTIVE HUMAN POSE AND ACTION RECOGNITION USING DYNAMICAL MOTION PRIMITIVES
Authors: JENKINS ODEST CHADWICKE , SERRANO GERMÁN GONZÁLEZ , LOPER MATTHEW M.
Published: July 2007

There is currently a division between real-world human performance and the decision making of socially interactive robots. This circumstance is partially due to the difficulty in estimating human cues, such as pose and gesture, from robot sensing. Towards bridging this division, we present a method for kinematic pose estimation and action recognition from monocular robot vision through the use of dynamical human motion vocabularies. Our notion of a motion vocabulary is comprised of movement primitives that structure a human's action space for decision making and predict human movement dynamics. Through prediction, such primitives can be used to both generate motor commands for specific actions and perceive humans performing those actions. In this paper, we focus specifically on the perception of human pose and performed actions using a known vocabulary of primitives. Given image observations over time, each primitive infers pose independently using its expected dynamics in the context of a particle filter. Pose estimates from a set of primitives inferencing in parallel are arbitrated to estimate the action being performed. The efficacy of our approach is demonstrated through interactive-time pose and action recognition over extended motion trials. Results evidence our approach requires small numbers of particles for tracking, is robust to unsegmented multi-action movement, movement speed, camera viewpoint and is able to recover from occlusions.
A MULTILAYER IN-PLACE LEARNING NETWORK FOR DEVELOPMENT OF GENERAL INVARIANCES
Authors: WENG JUYANG , LUWANG TIANYU , LU HONG , XUE XIANGYANG
Published: July 2007

Currently, there is a lack of general-purpose, in-place learning engines that incrementally learn multiple tasks, to develop "soft" multi-task-shared invariances in the intermediate internal representation while a developmental robot interacts with its environment. In-place learning is a biologically inspired concept, rooted in the genomic equivalence principle, meaning that each neuron is responsible for its own development while interacting with its environment. With in-place learning, there is no need for a separate learning network. Computationally, biologically inspired, in-place learning provides unusually efficient learning algorithms whose simplicity, low computational complexity, and generality are set apart from typical conventional learning algorithms. We present in this paper the multiple-layer in-place learning network (MILN) for this ambitious goal. As a key requirement for autonomous mental development, the network enables both unsupervised and supervised learning to occur concurrently, depending on whether motor supervision signals are available or not at the motor end (the last layer) during the agent's interactions with the environment. We present principles based on which MILN automatically develops invariant neurons in different layers and why such invariant neuronal clusters are important for learning later tasks in open-ended development. From sequentially sensed sensory streams, the proposed MILN incrementally develops a hierarchy of internal representations. The global invariance achieved through multi-layer invariances, with increasing invariance from early layers to the later layers. Experimental results with statistical performance measures are presented to show the effects of the principles.
Human connexin26 and connexin30 form functional heteromeric and heterotypic channels
Authors: Yum Sabrina W. , Zhang Junxian , Valiunas Virginijus , Kanaporis Giedrius , Brink Peter R. , White Thomas W. , Scherer Steven S.
Published: July 2007

Mutations in GJB2 and GJB6, the genes that encode the human gap junction proteins connexin26 (Cx26) and connexin30 (Cx30), respectively, cause hearing loss. Cx26 and Cx30 are both expressed in the cochlea, leading to the potential formation of heteromeric hemichannels and heterotypic gap junction channels. To investigate their interactions, we expressed human Cx26 and Cx30 individually or together in HeLa cells. When they were expressed together, Cx26 and Cx30 appeared to interact directly (by their colocalization in gap junction plaques, by coimmunoprecipitation, and by fluorescence resonance energy transfer). Scrape-loading cells that express either Cx26 or Cx30 demonstrated that Cx26 homotypic channels robustly transferred both cationic and anionic tracers, whereas Cx30 homotypic channels transferred cationic but not anionic tracers. Cells expressing both Cx26 and Cx30 also transferred both cationic and anionic tracers by scrape loading, and the rate of calcein (an anionic tracer) transfer was intermediate between their homotypic counterparts by fluorescence recovery after photobleaching. Fluorescence recovery after photobleaching also showed that Cx26 and Cx30 form functional heterotypic channels, allowing the transfer of calcein, which did not pass the homotypic Cx30 channels. Electrophysiological recordings of cell pairs expressing different combinations of Cx26 and/or Cx30 demonstrated unique gating properties of cell pairs expressing both Cx26 and Cx30. These results indicate that Cx26 and Cx30 form functional heteromeric and heterotypic channels, whose biophysical properties and permeabilities are different from their homotypic counterparts.
RhoA regulation of NF-κB activation is mediated by COX-2-dependent feedback inhibition of IKK in kidney epithelial cells
Authors: Polk William W. , Ellis Maureen E. , Kushleika John V. , Simmonds P. Lynne , Woods James S.
Published: July 2007

Numerous studies have demonstrated a central role of renal tubular epithelial cells in the etiology of kidney injury and disease through the elaboration of inflammatory mediators. However, little is known about the cellular signaling mechanisms involved in this process. In this study we employed normal rat kidney epithelial (NRK52E) cells to identify a novel LPS-induced signaling pathway in which RhoA-mediated AP-1 activity promotes expression of cyclooxygenase-2 (COX-2) with consequent feedback inhibition of NF-κB activation through IKKβ. Inhibition of RhoA signaling using either the RhoA kinase inhibitor Y-27632 or a dominant negative mutant of RhoA (RhoA-DN) dramatically extended the duration of p65-DNA binding, IκBα phosphorylation, and IKKβ activity following LPS treatment. Prolongation of events associated with NF-κB activation was also observed in cells pretreated and/or cotransfected with the JNK inhibitor SP600125 or deletion mutants of MEKK1 (MEKK1-KD) or Jun (Jun-DN). Conversely, constitutive expression of RhoA prevented NF-κB activation by LPS, and this effect was reversed by cotransfection with MEKK1-KD. In addition, we found that the RhoA/AP-1 signaling axis plays a necessary role in COX-2 expression by LPS and that this effect is independent of NF-κB activation. Moreover, inhibition of COX-2 activity results in persistent p65-DNA binding, IκBα phosphorylation, and IKKβ activity, similar to that observed after prevention of RhoA/AP-1 axis signaling. These findings suggest that COX-2 links the RhoA/AP-1 signaling cascade to NF-κB activation, thereby defining a novel integrated model for regulation of the inflammatory response of kidney epithelial cells to LPS and potentially other external stimuli.
Epidermal growth factor receptor signaling modulates apoptosis via p38α MAPK-dependent activation of Bax in intestinal epithelial cells
Authors: Sheng George , Guo Jun , Warner Brad W.
Published: July 2007

Previous studies have demonstrated that the proapoptotic protein Bax plays an important role in the elevated enterocyte apoptosis that occurs during the intestinal adaptation response to massive small bowel resection (SBR). Additionally, epidermal growth factor receptor (EGFR) activation prevents SBR-induced enterocyte apoptosis. The present study aims to delineate the relationship between EGFR activity and intestinal epithelial cell apoptosis. Treatment of model intestinal epithelial cells (RIEC-18) with both a selective EGFR inhibitor (ZD1839) and EGFR small interfering RNA knockdown resulted in a dramatic increase in apoptosis, accompanied by rapid phosphorylation of p38α. Concurrently, Bax underwent conformational changes consistent with activation and translocated to mitochondria. In contrast, EGF stimulation enhanced cell survival by attenuating p38α phosphorylation, Bax conformational change, mitochondrial trafficking, and apoptosis. These results demonstrate that that diminished EGFR activity initiates the intrinsic pathway of apoptosis through p38α-dependent Bax activation in intestinal epithelial cells. These finding provide mechanistic insight into the role that EGFR signaling plays in the regulation of enterocyte apoptosis following massive intestinal loss.
Wnt-induced secreted protein-1 is a prohypertrophic and profibrotic growth factor
Authors: Colston J. T. , de la Rosa S. D. , Koehler M. , Gonzales K. , Mestril R. , Freeman G. L. , Bailey S. R. , Chandrasekar B.
Published: July 2007

Wnt1-induced secreted protein-1 (WISP-1) is a member of the cysteine-rich 61, connective tissue growth factor, and nephroblastoma overexpressed (CCN) family of growth factors and is expressed in the heart at low basal levels. The purpose of this study was to investigate whether WISP-1 is upregulated in postinfarct myocardium and whether WISP-1 exerts prohypertrophic and mitogenic effects stimulating myocyte hypertrophy, cardiac fibroblast (CF) proliferation, and collagen expression. Male C57Bl/6 (25 g) mice underwent permanent occlusion of the left anterior descending coronary artery. mRNA and protein levels were analyzed by Northern and Western blot analyses. Cardiomyocyte hypertrophy was quantified by protein and DNA synthesis. CF proliferation was quantified by CyQuant assay, and soluble collagen release by Sircol assay. A time-dependent increase in WISP-1 expression was detected in vivo in the noninfarct zone of the left ventricle, which peaked at 24 h (3.1-fold, P < 0.01). Similarly, biglycan expression was increased by 3.71-fold ( P < 0.01). IL-1β and TNF-α expression preceded WISP-1 expression in vivo and stimulated WISP-1 expression in neonatal rat ventricular myocytes in vitro. WISP-1-induced cardiomyocyte hypertrophy was evidenced by increased protein (2.78-fold), but not DNA synthesis, and enhanced Akt phosphorylation and activity. Treatment of primary CF with WISP-1 significantly stimulated proliferation at 48 h (6,966 ± 264 vs. 5,476 ± 307 cells/well, P < 0.01) and enhanced collagen release by 72 h (18.4 ± 3.1 vs. 8.4 ± 1.0 ng/cell, P < 0.01). Our results demonstrate for the first time that WISP-1 and biglycan are upregulated in the noninfarcted myocardium in vivo, suggesting a positive amplification of WISP-1 signaling. WISP-1 stimulates cardiomyocyte hypertrophy, fibroblast proliferation, and ECM expression in vitro. These results suggest that WISP-1 may play a critical role in post-myocardial infarction remodeling.
Deleterious effects of sugar and protective effects of starch on cardiac remodeling, contractile dysfunction, and mortality in response to pressure overload
Authors: Chess David J. , Lei Biao , Hoit Brian D. , Azimzadeh Agnes M. , Stanley William C.
Published: July 2007

Little is known about the effects of the composition of dietary carbohydrate on the development of left ventricular (LV) hypertrophy (LVH) and heart failure (HF) under conditions of pressure overload. The objective of this study was to determine the effect of carbohydrate composition on LVH, LV function, and mortality in a mouse model of chronic pressure overload. Male C57BL/6J mice of 6 wk of age ( n = 14–16 mice/group) underwent transverse aortic constriction (TAC) or sham surgery and were fed either standard chow (STD; 32% corn starch, 35% sucrose, 3% maltodextrin, and 10% fat expressed as a percent of the total energy), high-starch chow (58% corn starch, 12% maltodextrin, and 10% fat), or high-fructose chow (9% corn starch, 61% fructose, and 10% fat). After 16 wk of treatment, mice with TAC fed the STD or high-fructose diets exhibited increased LV mass, larger end-diastolic and end-systolic diameters, and decreased ejection fraction compared with sham. The high-starch diet, in contrast, prevented changes in LV dimensions and contractile function. Cardiac mRNA for myosin heavy chain-β was increased dramatically in the fructose-fed banded animals, as was mortality (54% compared with 8% and 29% in the starch and STD banded groups, respectively). In conclusion, a diet high in simple sugar was deleterious, resulting in the highest mortality and expression of molecular markers of cardiac dysfunction in TAC animals compared with sham, whereas a high-starch diet blunted mortality, increases in cardiac mass, and contractile dysfunction.
Equilibrium Point Control Cannot be Refuted by Experimental Reconstruction of Equilibrium Point Trajectories
Authors: Kistemaker Dinant A. , Van Soest Arthur (Knoek) J. , Bobbert Maarten F.
Published: July 2007

In the literature, it has been hotly debated whether the brain uses internal models or equilibrium point (EP) control to generate arm movements. EP control involves specification of EP trajectories, time series of arm configurations in which internal forces and external forces are in equilibrium; if the arm is not in a specified EP, it is driven toward this EP by muscle forces arising due to central drive, reflexes, and muscle mechanics. EP control has been refuted by researchers claiming that EP trajectories underlying movements of subjects were complex. These researchers used an approach that involves applying force perturbations during movements of subjects and fitting a mass-spring-damper model to the kinematic responses, and then reconstructing the EP trajectory using the estimated stiffness, damping, and measured kinematics. In this study, we examined the validity of this approach using an EP-controlled musculoskeletal model of the arm. We used the latter model to simulate unperturbed and perturbed maximally fast movements and optimized the parameter values of a mass-spring-damper model to make it reproduce as best as possible the kinematic responses. It was shown that estimated stiffness not only depended on the “true” stiffness of the musculoskeletal model but on all of its dynamical parameters. Furthermore it was shown that reconstructed EP trajectories were in agreement with those presented in the literature but did not resemble the simple EP trajectories that had been used to generate the movement of the model. It was concluded that the refutation of EP control on the basis of results obtained with mass-spring-damper models was unjust.
Dynamic Amplitude Coding in the Auditory Cortex of Awake Rhesus Macaques
Authors: Malone Brian J. , Scott Brian H. , Semple Malcolm N.
Published: July 2007

In many animals, the information most important for processing communication sounds, including speech, consists of temporal envelope cues below ∼20 Hz. Physiological studies, however, have typically emphasized the upper limits of modulation encoding. Responses to sinusoidal AM (SAM) are generally summarized by modulation transfer functions (MTFs), which emphasize tuning to modulation frequency rather than the representation of the instantaneous stimulus amplitude. Unfortunately, MTFs fail to capture important but nonlinear aspects of amplitude coding in the central auditory system. We focus on an alternative data representation, the modulation period histogram (MPH), which depicts the spike train folded on the modulation period of the SAM stimulus. At low modulation frequencies, the fluctuations of stimulus amplitude in decibels are robustly encoded by the cycle-by-cycle response dynamics evident in the MPH. We show that all of the parameters that define a SAM stimulus—carrier frequency, carrier level, modulation frequency, and modulation depth—are reflected in the shape of cortical MPHs. In many neurons that are nonmonotonically tuned for sound amplitude, the representation of modulation frequency is typically sacrificed to preserve the mapping between the instantaneous discharge rate and the instantaneous stimulus amplitude, resulting in two response modes per modulation cycle. This behavior, as well as the relatively poor tuning of cortical MTFs, suggests that auditory cortical neurons are not well suited for operating as a “modulation filterbank.” Instead, our results suggest that <20 Hz, the processing of modulated signals is better described as envelope shape discrimination rather than modulation frequency extraction.
Function and Regulation of Human Copper-Transporting ATPases
Authors: Lutsenko Svetlana , Barnes Natalie L. , Bartee Mee Y. , Dmitriev Oleg Y.
Published: July 2007

Copper-transporting ATPases (Cu-ATPases) ATP7A and ATP7B are evolutionarily conserved polytopic membrane proteins with essential roles in human physiology. The Cu-ATPases are expressed in most tissues, and their transport activity is crucial for central nervous system development, liver function, connective tissue formation, and many other physiological processes. The loss of ATP7A or ATP7B function is associated with severe metabolic disorders, Menkes disease, and Wilson disease. In cells, the Cu-ATPases maintain intracellular copper concentration by transporting copper from the cytosol across cellular membranes. They also contribute to protein biosynthesis by delivering copper into the lumen of the secretory pathway where metal ion is incorporated into copper-dependent enzymes. The biosynthetic and homeostatic functions of Cu-ATPases are performed in different cell compartments; targeting to these compartments and the functional activity of Cu-ATPase are both regulated by copper. In recent years, significant progress has been made in understanding the structure, function, and regulation of these essential transporters. These studies raised many new questions related to specific physiological roles of Cu-ATPases in various tissues and complex mechanisms that control the Cu-ATPase function. This review summarizes current data on the structural organization and functional properties of ATP7A and ATP7B as well as their localization and functions in various tissues, and discusses the current models of regulated trafficking of human Cu-ATPases.
Regulatory Binding Partners and Complexes of NHE3
Authors: Donowitz Mark , Li Xuhang
Published: July 2007

NHE3 is the brush-border (BB) Na+/H+exchanger of small intestine, colon, and renal proximal tubule which is involved in large amounts of neutral Na+absorption. NHE3 is a highly regulated transporter, being both stimulated and inhibited by signaling that mimics the postprandial state. It also undergoes downregulation in diarrheal diseases as well as changes in renal disorders. For this regulation, NHE3 exists in large, multiprotein complexes in which it associates with at least nine other proteins. This review deals with short-term regulation of NHE3 and the identity and function of its recognized interacting partners and the multiprotein complexes in which NHE3 functions.
Breast Cancer Antiestrogen Resistance-3 Expression Regulates Breast Cancer Cell Migration through Promotion of p130Cas Membrane Localization and Membrane Ruffling
Authors: Schrecengost Randy S. , Riggins Rebecca B. , Thomas Keena S. , Guerrero Michael S. , Bouton Amy H.
Published: July 2007

Antiestrogens such as tamoxifen are widely used in the clinic to treat estrogen receptor–positive breast tumors. Resistance to tamoxifen can occur either de novo or develop over time in a large proportion of these tumors. Additionally, resistance is associated with enhanced motility and invasiveness in vitro. One molecule that has been implicated in tamoxifen resistance, breast cancer antiestrogen resistance-3 (BCAR3), has also been shown to regulate migration of fibroblasts. In this study, we investigated the role of BCAR3 in breast cancer cell migration and invasion. We found that BCAR3 was highly expressed in multiple breast cancer cell lines, where it associated with another protein, p130Cas (also known as breast cancer antiestrogen resistance-1; BCAR1), that plays a role in both tamoxifen resistance and cell motility. In cells with relatively low migratory potential, BCAR3 overexpression resulted in enhanced migration and colocalization with p130Cas at the cell membrane. Conversely, BCAR3 depletion from more aggressive breast cancer cell lines inhibited migration and invasion. This coincided with a relocalization of p130Cas away from the cell membrane and an attenuated response to epidermal growth factor stimulation that was characterized by a loss of membrane ruffles, decreased migration toward EGF, and disruption of p130Cas/Crk complexes. Based on these data, we propose that the spatial and temporal regulation of BCAR3/p130Cas interactions within the cell is important for controlling breast cancer cell motility. [Cancer Res 2007;67(13):6174–82]
Antitumor Activity of PR-171, a Novel Irreversible Inhibitor of the Proteasome
Authors: Demo Susan D. , Kirk Christopher J. , Aujay Monette A. , Buchholz Tonia J. , Dajee Maya , Ho Mark N. , Jiang Jing , Laidig Guy J. , Lewis Evan R. , Parlati Francesco , Shenk Kevin D. , Smyth Mark S. , Sun Congcong M. , Vallone Marcy K. , Woo Tina M. , Molineaux Christopher J. , Bennett Mark K.
Published: July 2007

Clinical studies with bortezomib have validated the proteasome as a therapeutic target for the treatment of multiple myeloma and non-Hodgkin's lymphoma. However, significant toxicities have restricted the intensity of bortezomib dosing. Here we describe the antitumor activity of PR-171, a novel epoxyketone-based irreversible proteasome inhibitor that is currently in clinical development. In comparison to bortezomib, PR-171 exhibits equal potency but greater selectivity for the chymotrypsin-like activity of the proteasome. In cell culture, PR-171 is more cytotoxic than bortezomib following brief treatments that mimic the in vivo pharmacokinetics of both molecules. Hematologic tumor cells exhibit the greatest sensitivity to brief exposure, whereas solid tumor cells and nontransformed cell types are less sensitive to such treatments. Cellular consequences of PR-171 treatment include the accumulation of proteasome substrates and induction of cell cycle arrest and/or apoptosis. Administration of PR-171 to animals results in the dose-dependent inhibition of the chymotrypsin-like proteasome activity in all tissues examined with the exception of the brain. PR-171 is well tolerated when administered for either 2 or 5 consecutive days at doses resulting in >80% proteasome inhibition in blood and most tissues. In human tumor xenograft models, PR-171 mediates an antitumor response that is both dose and schedule dependent. The antitumor efficacy of PR-171 delivered on 2 consecutive days is stronger than that of bortezomib administered on its clinical dosing schedule. These studies show the tolerability, efficacy, and dosing flexibility of PR-171 and provide validation for the clinical testing of PR-171 in the treatment of hematologic malignancies using dose-intensive schedules. [Cancer Res 2007;67(13):6383–91]
Sodium Selenite Induces Superoxide-Mediated Mitochondrial Damage and Subsequent Autophagic Cell Death in Malignant Glioma Cells
Authors: Kim Eun Hee , Sohn Seonghyang , Kwon Hyuk Jae , Kim Seung U. , Kim Min-Jung , Lee Su-Jae , Choi Kyeong Sook
Published: July 2007

Malignant gliomas are resistant to various proapoptotic therapies, such as radiotherapy and conventional chemotherapy. In this study, we show that selenite is preferentially cytotoxic to various human glioma cells over normal astrocytes via autophagic cell death. Overexpression of Akt, survivin, XIAP, Bcl-2, or Bcl-xL failed to block selenite-induced cell death, suggesting that selenite treatment may offer a potential therapeutic strategy against malignant gliomas with apoptotic defects. Before selenite-induced cell death in glioma cells, disruption of the mitochondrial cristae, loss of mitochondrial membrane potential, and subsequent entrapment of disorganized mitochondria within autophagosomes or autophagolysosomes along with degradation of mitochondrial proteins were noted, showing that selenite induces autophagy in which mitochondria serve as the main target. At the early phase of selenite treatment, high levels of superoxide anion were generated and overexpression of copper/zinc superoxide dismutase or manganese superoxide dismutase, but not catalase, significantly blocked selenite-induced mitochondrial damage and subsequent autophagic cell death. Furthermore, treatment with diquat, a superoxide generator, induced autophagic cell death in glioma cells. Taken together, our study clearly shows that superoxide anion generated by selenite triggers mitochondrial damage and subsequent mitophagy, leading to irreversible cell death in glioma cells.[Cancer Res 2007;67(13):6314–24]
AKT1 Amplification Regulates Cisplatin Resistance in Human Lung Cancer Cells through the Mammalian Target of Rapamycin/p70S6K1 Pathway
Authors: Liu Ling-Zhi , Zhou Xiang-Dong , Qian Guisheng , Shi Xianglin , Fang Jing , Jiang Bing-Hua
Published: July 2007

Cisplatin [cis-diaminodichloroplatinum (II) (CDDP)] is one of the most widely used and effective therapeutic agents for many kinds of cancers. However, its efficiency is limited due to development of drug resistance. In this study, we showed that CDDP resistance was associated with AKT1 overexpression and gene amplification in human lung cancer cells that acquired the drug resistance. We showed that AKT1 forced expression in the cells was sufficient to render the cells CDDP resistant, and that AKT1 inhibition by its dominant negative mutant reversed the CDDP-resistant cells to be CDDP sensitive. These results show that AKT1 activity is essential for regulating CDDP resistance in cultured lung cancer cells. To study whether these results were correlated with human lung cancer tumors, we randomly selected tumor samples from human lung cancer patients to study the correlation of AKT activation and CDDP resistance in clinical tumor samples. We showed that AKT activation was highly related to CDDP chemosensitivity in human tumor tissues. Our results further showed that AKT1 induced lung cancer cells to become resistant to CDDP through the mammalian target of the rapamycin (mTOR) signaling pathway. These studies conclude that AKT amplification and the mTOR pathway play an important role in human lung cancer cells acquiring CDDP resistance, which represents a new mechanism for acquiring CDDP resistance and a potential novel therapeutic target for overcoming CDDP resistance in human cancer in the future. [Cancer Res 2007;67(13):6325–32]
Human Neuroblastoma Cells Trigger an Immunosuppressive Program in Monocytes by Stimulating Soluble HLA-G Release
Authors: Morandi Fabio , Levreri Isabella , Bocca Paola , Galleni Barbara , Raffaghello Lizzia , Ferrone Soldano , Prigione Ignazia , Pistoia Vito
Published: July 2007

HLA-G is overexpressed in different tumors and plays a role in immune escape. Because no information is available on HLA-G in relation to human neuroblastoma, we have investigated the expression of membrane-bound and secretion of soluble isoforms of HLA-G in neuroblastoma and functionally characterized their immunosuppressive activities. At diagnosis, serum soluble HLA-G (sHLA-G) levels were significantly higher in patients than in age-matched healthy subjects. In addition, patients who subsequently relapsed exhibited higher sHLA-G levels than those who remained in remission. Neuroblastoma patient sera selected according to high sHLA-G concentrations inhibited natural killer (NK) cell and CTL-mediated neuroblastoma cell lysis. Such lysis was partially restored by serum depletion of sHLA-G. In 6 of 12 human neuroblastoma cell lines, low HLA-G surface expression was not up-regulated by IFN-γ. Only the ACN cell line secreted constitutively sHLA-G. IFN-γ induced de novo sHLA-G secretion by LAN-5 and SHSY5Y cells and enhanced that by ACN cells. Primary tumor lesions from neuroblastoma patients tested negative for HLA-G. Neuroblastoma patients displayed a higher number of sHLA-G–secreting monocytes than healthy controls. Incubation of monocytes from normal donors with IFN-γ or pooled neuroblastoma cell line supernatants significantly increased the proportion of sHLA-G–secreting cells. In addition, tumor cell supernatants up-regulated monocyte expression of CD68, HLA-DR, CD69, and CD71 and down-regulated IL-12 production. Our conclusions are the following: (a) sHLA-G serum levels are increased in neuroblastoma patients and correlate with relapse, (b) sHLA-G is secreted by monocytes activated by tumor cells rather than by tumor cells themselves, and (c) sHLA-G dampens anti-neuroblastoma immune responses. [Cancer Res 2007;67(13):6433–41]
Lineage-Specific Dependency of Lung Adenocarcinomas on the Lung Development Regulator TTF-1
Authors: Tanaka Hisaaki , Yanagisawa Kiyoshi , Shinjo Keiko , Taguchi Ayumu , Maeno Ken , Tomida Shuta , Shimada Yukako , Osada Hirotaka , Kosaka Takayuki , Matsubara Hideo , Mitsudomi Tetsuya , Sekido Yoshitaka , Tanimoto Mitsune , Yatabe Yasushi , Takahashi Takashi
Published: July 2007

Emerging evidence, although currently very sparse, suggests the presence of “lineage-specific dependency” in the survival mechanisms of certain cancers. TTF-1 has a decisive role as a master regulatory transcription factor in lung development and in the maintenance of the functions of terminal respiratory unit (TRU) cells. We show that a subset of lung adenocarcinoma cell lines expressing TTF-1, which presumably represent those derived from the TRU lineage, exhibit marked dependence on the persistent expression of TTF-1. The inhibition of TTF-1 by RNA interference (RNAi) significantly and specifically induced growth inhibition and apoptosis in these adenocarcinoma cell lines. Furthermore, a fraction of TTF-1–expressing tumors and cell lines displayed an increase in the gene dosage of TTF-1 in the analysis of 214 patients with non–small-cell lung cancer, including 174 adenocarcinomas, showing a tendency of higher frequency of increased gene copies at metastatic sites than at primary sites (P = 0.07, by two-sided Fisher's exact test). These findings strongly suggest that in addition to the development and maintenance of TRU lineages in normal lung, sustained TTF-1 expression may be crucial for the survival of a subset of adenocarcinomas that express TTF-1, providing credence for the lineage-specific dependency model. [Cancer Res 2007;67(13):6007–11]
Cholesterol Sensitivity of Endogenous and Myristoylated Akt
Authors: Adam Rosalyn M. , Mukhopadhyay Nishit K. , Kim Jayoung , Di Vizio Dolores , Cinar Bekir , Boucher Kelly , Solomon Keith R. , Freeman Michael R.
Published: July 2007

The serine-threonine kinase, Akt, has been linked to cholesterol-sensitive signaling mechanisms, suggesting a possible means whereby cholesterol might affect tumor cell growth and survival. However, it has not been shown whether Akt itself, as distinct from upstream components of the pathway (e.g., membrane phosphoinositides), can be directly responsible for cholesterol-mediated effects. Consistent with this possibility, we identified an Akt1 subpopulation in cholesterol-rich lipid raft fractions prepared from LNCaP human prostate cancer cells. Phosphorylation of this Akt subspecies was ablated with methyl-β-cyclodextrin, a cholesterol-binding compound, under conditions where nonlipid raft-resident Akt was unaffected. A myristoylated Akt1 (MyrAkt1) fusion protein expressed in LNCaP cells was found to be highly enriched in lipid rafts, indicating that oncogenic Akt is overrepresented in cholesterol-rich membranes compared with wild-type Akt. Notably, lipid raft-resident MyrAkt1 exhibited a markedly distinct substrate preference compared with MyrAkt1 immunoprecipitated from cytosol and nonraft membrane fractions, suggesting a redirection of signal transduction when the protein is present in cholesterol-rich membranes. Expression of MyrAkt1 in LNCaP cells overcame their characteristic dependence on constitutive signaling through the phosphoinositide 3′-kinase pathway. This protective effect was substantially diminished with cyclodextrin treatment. Phosphorylation of Akt substrates in lipid raft fractions, but not in cytosol/nonraft membrane fractions, was ablated with cyclodextrin. In addition, in control (LacZ transfected) cells, lipid raft fractions were relatively enriched in phosphorylated Akt substrates. Collectively, these data show that a subpopulation of Akt is cholesterol sensitive and that the oncogenic effects conferred by myristoylation arise, in part, from the tendency of the membrane-targeted form of the protein to reside in cholesterol-rich membrane microdomains. [Cancer Res 2007;67(13):6238–46]
Nuclear and Cytoplasmic Survivin: Molecular Mechanism, Prognostic, and Therapeutic Potential
Authors: Stauber Roland H. , Mann Wolf , Knauer Shirley K.
Published: July 2007

Survivin's proposed dual role as an apoptosis inhibitor and a mitotic effector positioned it in the front line of cancer research. Notably, survivin is detected as a cytoplasmic and nuclear protein in cancer patients, which stimulated numerous studies to investigate and to speculate on the functional and prognostic significance of its dynamic localization. Recent evidence shows that the direct interaction of survivin with the nuclear export receptor Crm1 is critically involved in its intracellular localization and cancer-relevant functions. Here, we review our current understanding of the Crm1/survivin interface and discuss its potential prognostic and therapeutic relevance. [Cancer Res 2007;67(13):5999–6002]
MicroRNA Expression Profiling in Prostate Cancer
Authors: Porkka Kati P. , Pfeiffer Minja J. , Waltering Kati K. , Vessella Robert L. , Tammela Teuvo L.J. , Visakorpi Tapio
Published: July 2007

MicroRNAs (miRNA) are small, endogenously expressed noncoding RNAs that negatively regulate expression of protein-coding genes at the translational level. Accumulating evidence, such as aberrant expression of miRNAs, suggests that they are involved in the development of cancer. They have been identified in various tumor types, showing that different sets of miRNAs are usually deregulated in different cancers. To identify the miRNA signature specific for prostate cancer, miRNA expression profiling of 6 prostate cancer cell lines, 9 prostate cancer xenografts samples, 4 benign prostatic hyperplasia (BPH), and 9 prostate carcinoma samples was carried out by using an oligonucleotide array hybridization method. Differential expression of 51 individual miRNAs between benign tumors and carcinoma tumors was detected, 37 of them showing down-regulation and 14 up-regulation in carcinoma samples, thus identifying those miRNAs that could be significant in prostate cancer development and/or growth. There was a significant trend (P = 0.029) between the expression of miRNAs and miRNA locus copy number determined by array comparative genomic hybridization, indicating that genetic aberrations may target miRNAs. Hierarchical clustering of the tumor samples by their miRNA expression accurately separated the carcinomas from the BPH samples and also further classified the carcinoma tumors according to their androgen dependence (hormone naive versus hormone refractory), indicating the potential of miRNAs as a novel diagnostic and prognostic tool for prostate cancer. [Cancer Res 2007;67(13):6130–5]
Effects of Chromatin-Modifying Agents on CD34+ Cells from Patients with Idiopathic Myelofibrosis
Authors: Shi Jun , Zhao Yan , Ishii Takefumi , Hu Wenyang , Sozer Selcuk , Zhang Wei , Bruno Edward , Lindgren Valerie , Xu Mingjiang , Hoffman Ronald
Published: July 2007

Idiopathic myelofibrosis (IM) is likely the consequence of both the acquisition of genetic mutations and epigenetic changes that silence critical genes that control cell proliferation, differentiation, and apoptosis. We have explored the effects of the sequential treatment with the DNA methyltransferase inhibitor, decitabine [5-aza-2′-deoxycytidine (5azaD)], followed by the histone deacetylase inhibitor, trichostatin A (TSA), on the behavior of IM CD34+ cells. Unlike normal CD34+ cells where 5azaD/TSA treatment leads to the expansion of CD34+ cells and marrow-repopulating cells, treatment of IM CD34+ cells results in a reduction of the number of total cells, CD34+ cells, and assayable hematopoietic progenitor cells (HPC). In IM, HPCs are either heterozygous or homozygous for the JAK2V617F mutation or possess wild-type JAK2 in varying proportions. Exposure of IM CD34+ cells to 5azaD/TSA resulted in a reduction of the proportion of JAK2V617F-positive HPCs in 83% of the patients studied and the reduction in the proportion of homozygous HPCs in 50% of the patients. 5azaD/TSA treatment led to a dramatic reduction in the number of HPCs that contained chromosomal abnormalities in two JAK2V617F-negative IM patients. IM is characterized by constitutive mobilization of HPCs, which has been partly attributed to decreased expression of the chemokine receptor CXCR4. Treatment of IM CD34+ cells with 5azaD/TSA resulted in the up-regulation of CXCR4 expression by CD34+ cells and restoration of their migration in response to SDF-1. These data provide a rationale for sequential therapy with chromatin-modifying agents for patients with IM. [Cancer Res 2007;67(13):6417–24]
Incorporation of an Internal Ribosome Entry Site–Dependent Mechanism in Arsenic-Induced GADD45α Expression
Authors: Chang Qingshan , Bhatia Deepak , Zhang Yadong , Meighan Terry , Castranova Vince , Shi Xianglin , Chen Fei
Published: July 2007

We have previously shown that trivalent arsenic (arsenite, As3+) is able to induce GADD45α expression in human bronchial epithelial cells through activation of c-Jun NH2-terminal kinase and nucleolin-dependent mRNA stabilization. In the present report, we show that As3+ is capable of inducing translation of the GADD45α protein through a cap-independent, or rather, an internal ribosome entry site (IRES)–dependent mechanism. In growth-arrested cells, As3+ elevated the GADD45α protein level in a dose- and time-dependent manner which did not correlate with the GADD45α mRNA expression. Pretreatment of the cells with rapamycin, an inhibitor for the cap-dependent translation machinery through the suppression of mTOR and p70S6 kinase, failed to affect the induction of the GADD45α protein induced by As3+. Sequence analysis revealed a potential IRES element in the 5′-untranslated region of the GADD45α mRNA. This IRES element in the 5′-untranslated region of the GADD45α mRNA is functional in mediating As3+-induced translation of the GADD45α protein in a dicistronic reporter gene activity assay. Immunoprecipitation and proteomic studies suggest that As3+ impairs the assembly of the cap-dependent initiating complex for general protein translation but increases the association of human elongation factor 2 and human heterogeneous nuclear ribonucleoprotin with this complex. Thus, these results suggest that in growth-arrested cells, As3+ is still capable of inducing GADD45α expression through an IRES-dependent translational regulation. [Cancer Res 2007;67(13):6146–54]
The Role of Vascular Cell Adhesion Molecule-1 in Tumor Immune Evasion
Authors: Wu T-C.
Published: July 2007

Tumor immune escape is a critical trait of cancer but the mechanisms involved have yet to fully emerge. One recent study has shown that tumor cells can escape T-cell immunity by overexpressing the endothelial cell adhesion molecule vascular cell adhesion molecule-1 (VCAM-1), which normally mediates leukocyte extravasion to sites of tissue inflammation. Renal cell carcinoma (RCC) was identified as one tumor type where VCAM-1 is commonly highly overexpressed. Together, our findings suggest that RCCs might exploit VCAM-1 overexpression for immune escape. [Cancer Res 2007;67(13):6003–6]
Pulmonary Vascular Manifestations of Hereditary Hemorrhagic Telangiectasia (Rendu-Osler Disease)
Authors: Cottin Vincent , Dupuis-Girod Sophie , Lesca Gaetan , Cordier Jean-François
Published: July 2007

Hereditary hemorrhagic telangiectasia (HHT) or Rendu-Osler-Weber disease is a genetic disorder with autosomal dominance and variable penetrance, characterized by epistaxis, telangiectasia and visceral manifestations of the disease. The estimated minimal prevalence is 1/10,000 inhabitants. The diagnosis is established on clinical criteria, and may be further confirmed by the identification of causative mutations in either the ENG or the ACVRL1 gene coding for endoglin and ALK1, respectively. Pulmonary vascular manifestations of HHT include pulmonary arteriovenous malforma- tions (PAVMs; especially in patients with ENG mutations) and less frequently pulmonary hypertension (especially in patients with ACVRL1 mutations). In 15–33% of patients with HHT, PAVMs consist of abnormal communications between pulmonary arteries and pulmonary veins, causing right-to-left shunting, and thus, frequently hypoxemia and dyspnea on exertion, although PAVMs may remain asymptomatic and frequently undiagnosed unless complications occur. PAVMs result in severe and frequent complications often at a young age, which may reveal the diagnosis, e.g. transient ischemic attack and cerebral stroke (10–19% of patients), systemic severe infections and abscesses (including cerebral abscess in 5–19% of patients), and rarely massive hemoptysis or hemothorax. Infections in HHT are related to the right-to-left shunting that bypasses the pulmonary capillaries and facilitates the passage of septic or aseptic emboli into the systemic and especially cerebral circulation, and potentially to minor defects in innate immunity. Treatment of PAVMs based on transcatheter coil vaso-occlusion of the feeding artery significantly decreases right-to-left shunting, hypoxemia and dyspnea on exertion, and reduces the risk of systemic complications. Long-term follow-up is warranted after transcatheter vaso-occlusion of PAVMs due to frequent recanalization of treated PAVMs and development or growth of untreated PAVMs. Patients with HHT should be informed of the risk of PAVM and potentially severe complications occurring in heretofore asymptomatic subjects. All adult patients with HHT should be proposed systematic screening for PAVM, by contrast echocardiography (preceded by anteroposterior chest radiograph) or computed tomography of the chest. Pulmonary hypertension is rare in HHT, and may be due either to systemic arteriovenous shunting in the liver increasing cardiac output or be clinically and histologically indistinguishable from idiopathic pulmonary arterial hypertension. Pulmonary hypertension is detected by systematic examination of right cardiac cavities and tricuspid regurgitation flow at echocardiography, and the diagnosis is established by right heart catheterization.
Influence of Warm Ischemia Time on Peripheral-Type Benzodiazepine Receptor: A New Aspect of the Role of Mitochondria
Authors: Doucet Carole , Zhang Keqiang , Desurmont Thibault , Hebrard William , Scepi Michel , Nadeau Cedric , Cau Jerome , Leyre Pierre , Febrer Guillaume , Carretier Michel , Richer Jean Pierre , Papadopoulos Vassilios , Hauet Thierry , Burucoa Christophe , Goujon Jean Michel
Published: July 2007

The peripheral benzodiazepine receptor (PBR) is located mainly in the outer mitochondrial membrane and many functions are associated directly or indirectly with the PBR. We have studied the influence of different durations of warm ischemia (WI) on renal function, tissue damage and PBR expression in a Large Whitepig model. After a midline incision, the renal pedicle was clamped for 10 (WI10), 30 (WI30), 45 (WI45), 60 (WI60) or 90 min (WI90), and blood and renal tissue samples were collected between 1 day and 2 weeks after reperfusion for assessment of renal function. Metabolite excretion associated with renal ischemia reperfusion injury such as trimethylamine-N-oxide (TMAO) was quantified in blood by magnetic resonance spectroscopy. PBR mRNA and protein expression were determined in renal tissue. TMAO levels rose progressively and significantly with increasing duration of WI. PBR mRNA expression was upregulated between 3 h and 1 day after reperfusion in WI30, WI45 and WI60. Its upregulation was noted 3 days after reperfusion in WI90. At day 14, PBR transcript expression was not different from basal level in any group. PBR protein followed the same pattern. These findings suggest a new role for PBR which could be a major target in the regeneration process during ischemia reperfusion.
Pulse Pressure Is an Independent Predictor of Aortic Stiffness in Patients with Mild to Moderate Chronic Kidney Disease
Authors: Stancanelli Benedetta , Malatino Lorenzo S. , Malaponte Graziella , Noto Paola , Giuffrè Eliana , Caruso Alessia , Gagliano Carmela , Zoccolo Anna Maria , Puccia Giuseppe , Castellino Pietro
Published: July 2007

Background: In patients with end-stage renal disease pulse wave velocity (PWV) has been widely assessed, but its behavior in mild to moderate chronic kidney disease (CKD) has been less investigated. We evaluated PWV in mild to moderate CKD. Methods: We studied 31 patients with grade II–IV CKD. Aortic PWV (aPWV), aortic and upper limb augmentation index, creatinine clearance, C-reactive protein, serum fibrinogen, interleukin-1, interleukin-6, tumor necrosis factor, albumin, total and high-density lipoprotein cholesterol and blood pressure were evaluated. Results: aPWV (7.95 ± 0.64 m/s), but not augmentation index was significantly higher (p = 0.03) in CKD patients than age-matched healthy subjects (aPWV: 6.24 ± 0.43 m/s; upper limb: 32.8 ± 1.9; aortic: 27.7 ± 1.9). At univariate regression analysis, aPWV was significantly correlated with age (r = 0.44; p = 0.013), interleukin-6 (r = 0.43; p = 0.027), pulse (r = 0.39; p = 0.029), systolic blood pressure (r = 0.37; p = 0.038) and tumor necrosis factor (r = 0.39; p = 0.029). At multivariate analysis, pulse pressure was the only significant independent determinant (β = 0.37; p = 0.05) of aPWV. Conclusion: The results of this study confirm an aPWV increase in mild to moderate CKD and emphasize association between pulse pressure and PWV, independently of renal failure.
The von Willebrand factor antagonist (GPG-290) prevents coronary thrombosis without prolongation of bleeding time
Authors: Wadanoli Michael , Sako Dianne , Shaw Gray , Schaub Robert , Wang Qin , Tchernychev Boris , Xu Jin , Porter Thomas , Huang Qinheng
Published: July 2007

The interaction between von Willebrand factor (VWF) and platelet glycoprotein Ibα (GPIbα) is a critical step that allows platelet adhesion, activation and subsequent thrombus formation to the injured vessel wall under high-shear conditions. In this study, we sought to investigate 1) whether GPG-290, a recombinant human GPIbα chimeric protein, would prevent thrombosis in a canine model of coronary thrombosis by blocking VWFGPIbα interaction; and 2) whether desmopressin (DDAVP), a VWF release stimulant, could reduce the prolonged bleeding time caused by a 10x efficacious dose of GPG-290. The antithrombotic efficacy of GPG-290 was evaluated by the in-vivo ability to prevent cyclic flow reductions (CFRs) and ex-vivo inhibition of platelet adhesion/aggregation reflected by prolongation of Platelet Function Analyzer (PFA-100®) collagen /ADP closure time. The anti-hemostatic effect was assessed by template bleeding time. GPG-290 at doses of 25, 50 and 100 μg/kg abolished CFRs in 67%,100% and 100% of the treated dogs without bleeding time prolongation, respectively; GPG-290 dose-dependently prolonged the ex-vivo collagen/ADP-closure time, while it had no effects on plasma VWF antigen level (VWF:Ag) and VWF-collagen binding activity (VWF:CB); the prolonged template bleeding time caused by 500 μg/kg of GPG-290 was prevented by intravenous infusion of DDAVP (0.3 μg/kg). In conclusion, GPG-290 appears to be an effective agent for treating arterial thrombosis without bleeding time prolongation.