bluuebunny/crossref_metadata_2025 huggingface dataset:
Heterogeneity in conduit artery function in humans: impact of arterial size
Authors: Thijssen Dick H. J. , Dawson Ellen A. , Black Mark A. , Hopman Maria T. E. , Cable N. Timothy , Green Daniel J.
Published: September 2008

To determine whether conduit artery size affects functional responses, we compared the magnitude, time course, and eliciting shear rate stimulus for flow-mediated dilation (FMD) in healthy men ( n = 20; 31 ± 7 yr). Upper limb (brachial and radial) and lower limb (common and superficial femoral) FMD responses were simultaneously assessed, whereas popliteal responses were measured in the same subjects during a separate visit. Glyceryl trinitrate (GTN)-mediated responses were similarly examined. Edge detection and wall tracking of high-resolution B-mode arterial ultrasound images, combined with synchronized Doppler waveform envelope analysis, were used to calculate conduit artery diameter, blood flow, and shear rate continuously across the cardiac cycle. Baseline artery size correlated inversely with the FMD response ( r = −0.57, P < 0.001). Within-artery comparisons revealed a significant inverse correlation between artery size and FMD% for the radial ( r = −0.66, P = 0.001), brachial ( r = −0.55, P = 0.01), and popliteal artery ( r = −0.48, P = 0.03), but not for the superficial and common femoral artery. Normalization of FMD responses for differences in eliciting shear rate did not abolish the between-artery relationship for artery function and size ( r = −0.48, P < 0.001), suggesting that differences between artery function responses were not entirely due to size-related differences in shear rate. This was reinforced by a significant between-artery correlation for GTN responses and baseline artery size ( r = −0.74, P < 0.001). In summary, systematic differences exist in vascular function responses of conduit arteries that differ in size. This raises the possibility that differences in artery size within or between individuals may influence functional responses.
ERKs/p53 signal transduction pathway is involved in doxorubicin-induced apoptosis in H9c2 cells and cardiomyocytes
Authors: Liu Jiahao , Mao Weike , Ding Bo , Liang Chang-seng
Published: September 2008

The cardiotoxic effects of doxorubicin, a potent chemotherapeutic agent, have been linked to DNA damage, oxidative mitochondrial damage, and nuclear translocation of p53, but the exact molecular mechanisms causing p53 transactivation and doxorubicin-induced cardiomyopathy are not clear. The present study was carried out to determine whether extracellular signal-regulated kinases (ERKs), which are known to be activated by DNA damaging agents, are responsible for doxorubicin-induced p53 activation and oxidative mitochondrial damage in H9c2 cells. Cell death was measured by terminal deoxynucleotidyl transferase dUTP-mediated nick-end labeling, annexin V-fluorescein isothiocyanate, activation of caspase-9 and -3, and cleavage of poly(ADP-ribose) polymerase (PARP). We found that doxorubicin produced cell death in H9c2 cells in a time-dependent manner, beginning at 6 h, and these changes are associated decreased expression of Bcl-2, increases in Bax and p53 upregulated modulator of apoptosis-α expression, and collapse of mitochondria membrane potential. The changes in cell death and Bcl-2 family proteins, however, were preceded by earlier activation and nuclear translocation of ERKs, followed by increased phosphorylation at Ser15 and nuclear translocation of the phosphorylated p53. The functional importance of ERK1/2 and p53 in doxorubicin-induced toxicity was further demonstrated by the specific ERK inhibitor U-0126 and p53 inhibitor pifithrin (PFT)-α, which abrogated the changes in Bcl-2 family proteins and cell death produced by doxorubicin. U-0126 blocked the phosphorylation and nuclear translocation of both ERK1/2 and p53, whereas PFT-α blocked only the changes in p53. Doxorubicin and ERK inhibitors produced similar changes in ERK1/2-p53, PARP, and caspase-3 in neonatal rat cultured cardiomyocytes. Thus we conclude that ERK1/2 are functionally linked to p53 and that the ERK1/2-p53 cascade is the upstream signaling pathway responsible for doxorubicin-induced cardiac cell apoptosis. ERKs and p53 may be considered as novel therapeutic targets for the treatment of doxorubicin-induced cardiotoxicity.
Inhibition of rat aortic smooth muscle contraction by 2-methoxyestradiol
Authors: Gui Yu , Zheng Xi-Long , Zheng Jie , Walsh Michael P.
Published: September 2008

Recent studies suggest that 2-methoxyestradiol (2-ME), an estrogen metabolite, has a similar inhibitory effect as 17β-estradiol (E2) on vascular tone. However, it is not known whether 2-ME mediates the effects of E2or by what mechanism 2-ME regulates smooth muscle contraction. Therefore, we compared the effects of 2-ME and E2on rat aortic smooth muscle contraction. A preincubation with 2-ME (10 μM) for 1 h inhibited phenylephrine (PE)-induced tension in endothelium-intact, but not -denuded, tissues, whereas E2inhibited PE-induced contraction in both preparations. The effects of 2-ME and E2on endothelium-intact preparations were prevented by l-NAME hydrochloride (a nitric oxide synthase inhibitor). The 2-ME treatment reduced PE-induced phosphorylation of the 20-kDa myosin regulatory light chain. The inhibitory effects of 2-ME and E2were not affected by ICI-182780 (an estrogen receptor antagonist) or actinomycin D (a gene transcription inhibitor); however, the effect of 2-ME, but not E2, was prevented by cycloheximide (a protein synthesis inhibitor). Furthermore, the effect of E2was not blocked by 1-aminobenzotriazole (a cytochrome P-450 inhibitor) or Ro 41-0960 (a catechol- O-methyltransferase inhibitor). The effect of 2-ME was not mimicked by microtubule-interfering agents (nocodazole or Taxol). We conclude that 2-ME inhibits smooth muscle contractility through an endothelium- and nitric oxide-dependent mechanism, which does not involve estrogen receptors or microtubule disruption. The effect of 2-ME, but not E2, involves de novo protein synthesis. 2-ME does not mediate the inhibitory effect of E2on smooth muscle contraction. These results support a potentially important role of 2-ME in the regulation of smooth muscle tone in the vasculature.
Maturation of intracellular calcium homeostasis in sheep pulmonary arterial smooth muscle cells
Authors: Goyal Ravi , Creel Kara D. , Chavis Erica , Smith Gregory D. , Longo Lawrence D. , Wilson Sean M.
Published: September 2008

Cytosolic Ca2+ signaling dynamics are important to pulmonary arterial reactivity, and alterations are implicated in pulmonary vascular disorders. Yet, adaptations in cellular Ca2+ homeostasis and receptor-mediated Ca2+ signaling with maturation from fetal to adult life in pulmonary arterial smooth muscle cells (PASMCs) are not known. The present study tested the hypothesis that cytosolic Ca2+ homeostasis and receptor-generated Ca2+ signaling adapt with maturation in sheep PASMCs. Digitalized fluorescence microscopy was performed using isolated PASMCs from fetal and adult sheep that were loaded with the Ca2+ indicator fura 2. The results show that basal cytosolic and sarcoplasmic reticulum Ca2+ levels are attained before birth. Similarly, Ca2+ efflux pathways from the cytosol and basal as well as capacitative Ca2+ entry (CCE) are also developed before birth. However, receptor-mediated Ca2+ signaling adapts with maturation. Prominently, serotonin stimulation elicited Ca2+ elevations in very few fetal compared with adult PASMCs; in contrast, phenylephrine elevated Ca2+ in a similar percentage of fetal and adult PASMCs. Serotonin and phenylephrine elicited Ca2+ increases of a similar magnitude in reactive cells of fetus and adult, supporting the assertion that inositol trisphosphate signaling is intact. Caffeine and ATP elevated Ca2+ in equivalent numbers of fetal and adult PASMCs. However, the caffeine-induced cytosolic Ca2+ increase was significantly greater in fetal PASMCs, whereas the ATP-elicited increase was greater in adult cells. Overall, the results of this study demonstrate selective adaptations in receptor-mediated Ca2+ signaling, but not in cellular Ca2+ homeostasis.
Combined budesonide/formoterol therapy in conjunction with allergen avoidance ameliorates house dust mite-induced airway remodeling and dysfunction
Authors: Johnson Jill R. , Pacitto Stephanie R. , Wong Jonathan , Archer Elliot W. , Eirefelt Stefan , Miller-Larsson Anna , Jordana Manel
Published: September 2008

Allergic asthma is characterized by airway inflammation in response to chronic allergen exposure, resulting in remodeling of the airway wall accompanied by dysfunctional airway physiology. However, a link between the immune-inflammatory response to allergen and changes to airway structure and physiology has not yet been fully elucidated. Moreover, the impact of inhaled corticosteroids and β2-agonists, the primary pharmacotherapy for asthma, on this process has not been completely evaluated. In this study, we employed a murine model of chronic exposure to a common environmental aeroallergen, house dust mite, to recapitulate the phenotype of clinical asthma. By examining the therapeutic effects of corticosteroid/β2-agonist combination therapy with budesonide/formoterol (BUD/FORM) in this model of airway disease, we endeavored to determine the impact of BUD/FORM on lung inflammation, structure, and physiology. BUD/FORM was delivered either while allergen exposure was ongoing (concurrent therapy) or following the cessation of allergen exposure (postexposure therapy). Our results show that airway inflammation was substantially reduced in BUD/FORM-treated mice in the concurrent therapy group, whereas in the postexposure therapy group airway inflammation spontaneously resolved. In contrast, BUD/FORM was most effective in resolving several aspects of airway remodeling and bronchial hyperreactivity when delivered in conjunction with allergen withdrawal. This study demonstrates that although both BUD/FORM therapy and allergen avoidance independently reduce airway inflammation, only BUD/FORM therapy in conjunction with allergen avoidance can effectively reverse airway remodeling and bronchial hyperreactivity induced by chronic allergen exposure.
Upregulation of vascular calcium channels in neonatal piglets with hypoxia-induced pulmonary hypertension
Authors: Hirenallur-S. Dinesh K. , Haworth Steven T. , Leming Jeaninne T. , Chang James , Hernandez Guillermo , Gordon John B. , Rusch Nancy J.
Published: September 2008

Inhibition of voltage-gated, L-type Ca2+ (CaL) channels by clinical calcium channel blockers provides symptomatic improvement to some pediatric patients with pulmonary arterial hypertension (PAH). The present study investigated whether abnormalities of vascular CaL channels contribute to the pathogenesis of neonatal PAH using a newborn piglet model of hypoxia-induced PAH. Neonatal piglets exposed to chronic hypoxia (CH) developed PAH by 21 days, which was evident as a 2.1-fold increase in pulmonary vascular resistance in vivo compared with piglets raised in normoxia (N). Transpulmonary pressures (ΔPtp) in the corresponding isolated perfused lungs were 20.5 ± 2.1 mmHg (CH) and 11.6 ± 0.8 mmHg (N). Nifedipine reduced the elevated ΔPtp in isolated lungs of CH piglets by 6.4 ± 1.3 mmHg but only reduced ΔPtp in lungs of N piglets by 1.9 ± 0.2 mmHg. Small pulmonary arteries from CH piglets also demonstrated accentuated Ca2+-dependent contraction, and Ca2+ channel current was 3.94-fold higher in the resident vascular muscle cells. Finally, although the level of mRNA encoding the pore-forming α1C-subunit of the CaL channel was similar between small pulmonary arteries from N and CH piglets, a profound and persistent upregulation of the vascular α1C protein was detected by 10 days in CH piglets at a time when pulmonary vascular resistance was only mildly elevated. Thus chronic hypoxia in the neonate is associated with the anomalous upregulation of CaL channels in small pulmonary arteries in vivo and the resulting abnormal Ca2+-dependent resistance may contribute to the pathogenesis of PAH.
High levels of hyaluronan in idiopathic pulmonary arterial hypertension
Authors: Aytekin Metin , Comhair Suzy A. A. , de la Motte Carol , Bandyopadhyay Sudip K. , Farver Carol F. , Hascall Vincent C. , Erzurum Serpil C. , Dweik Raed A.
Published: September 2008

Hyaluronan (HA), a large glycosaminoglycan found in the ECM, has major roles in lung and vascular biology and disease. However, its role in idiopathic pulmonary arterial hypertension (IPAH) is unknown. We hypothesized that HA metabolism is abnormal in IPAH. We measured the plasma levels of HA in IPAH and healthy individuals. We also evaluated HA synthesis and the expression of HA synthases and hyaluronidases in pulmonary artery smooth muscle cells (PASMCs) from explanted lungs. Plasma HA levels were markedly elevated in IPAH compared with controls [HA (ng/ml, mean ± SD): IPAH 325 ± 80, control 28 ± 9; P = 0.02]. In vitro, unstimulated IPAH PASMCs produced high levels of HA compared with control cells [HA in supernatant (μg/ml, mean ± SD): IPAH 12 ± 2, controls 6 ± 0.9; P = 0.04]. HA levels were also higher in IPAH PASMC lysates. The increased HA was biologically relevant as shown by tissue staining and increased HA-specific binding of mononuclear cells to IPAH compared with control PASMCs [number of bound cells × 104(mean ± SD): IPAH 9.5 ± 3, control 3.0 ± 1; P = 0.01]. This binding was abrogated by the addition of hyaluronidase. HA synthase-2 and hyaluronidase-2 were predominant in control and IPAH PASMCs. Interestingly, the expressions of HA synthase-2 and hyaluronidase-2 were ∼2-fold lower in IPAH compared with controls [HA synthase-2 (relative expression mean ± SE): IPAH 4.3 ± 0.02, control 7.8 ± 0.1; P = 0.0004; hyaluronidase-2 (relative expression mean ± SE): IPAH 4.2 ± 0.06, control 7.6 ± 0.07; P = 0.008]. Thus patients with IPAH have higher circulating levels of HA, and PASMCs derived from IPAH lungs produce more HA compared with controls. This is associated with increased tissue levels and increased binding of inflammatory cells suggesting a role for HA in remodeling and inflammation in IPAH.
Effect of hypohydration on hyperthermic hyperpnea and cutaneous vasodilation during exercise in men
Authors: Fujii Naoto , Honda Yasushi , Hayashi Keiji , Kondo Narihiko , Nishiyasu Takeshi
Published: September 2008

We tested the hypothesis that, in humans, hypohydration attenuates hyperthermic hyperpnea during exercise in the heat. On two separate occasions, thirteen male subjects performed a fluid replacement (FR) and a no-fluid replacement (NFR) trial in random order. The subjects performed two bouts of cycle exercise (Ex1 and Ex2, 30–60 min) at 50% peak oxygen uptake (V̇o2 peak) in 35°C separated by a 70- to 80-min rest period, during which they drank water containing 25 mosmol/l sodium in the FR trial but not the NFR trial. The drinking in the FR trial nearly restored the body fluid to the euhydrated condition, so that the body fluid status differed between the trials before Ex2 (the difference in plasma osmolality before Ex2 was 9.4 mosmol/kgH2O; plasma volume was 7.6%, and body weight was 2.5%). The slopes of the linear relationships between ventilatory variables (minute ventilation, ventilatory equivalents for oxygen uptake and carbon dioxide output, tidal volume, respiratory frequency, and end-tidal CO2 pressure) and esophageal temperature (Tes) did not significantly differ between Ex1 and Ex2, or between the FR and NFR trials. On the other hand, during Ex2 in the NFR trial, the Tes threshold for the onset of increased forearm vascular conductance (FVC) was higher, and the slope and peak values of the relationship between FVC and Tes were lower than during Ex1 in the NFR trial and during Ex2 in the FR trial. These findings suggest that hypohydration does not affect the hyperthermic hyperpnea during exercise, although it markedly attenuates the cutaneous vasodilatory response.
Antixenograft tumor activity of a humanized anti-insulin-like growth factor-I receptor monoclonal antibody is associated with decreased AKT activation and glucose uptake
Authors: Shang Yonglei , Mao Yifan , Batson Jennifer , Scales Suzie J. , Phillips Gail , Lackner Mark R. , Totpal Klara , Williams Simon , Yang Jihong , Tang Zhijun , Modrusan Zora , Tan Christine , Liang Wei-Ching , Tsai Siao Ping , Vanderbilt Alexander , Kozuka Kenji , Hoeflich Klaus , Tien Janet , Ross Sarajane , Li Congfen , Lee Sang Hoon , Song An , Wu Yan , Stephan Jean-Philippe , Ashkenazi Avi , Zha Jiping
Published: September 2008

The insulin-like growth factor (IGF) system consists of two ligands (IGF-I and IGF-II), which both signal through IGF-I receptor (IGF-IR) to stimulate proliferation and inhibit apoptosis, with activity contributing to malignant growth of many types of human cancers. We have developed a humanized, affinity-matured anti-human IGF-IR monoclonal antibody (h10H5), which binds with high affinity and specificity to the extracellular domain. h10H5 inhibits IGF-IR-mediated signaling by blocking IGF-I and IGF-II binding and by inducing cell surface receptor down-regulation via internalization and degradation, with the extracellular and intracellular domains of IGF-IR being differentially affected by the proteasomal and lysosomal inhibitors. In vitro, h10H5 exhibits antiproliferative effects on cancer cell lines. In vivo, h10H5 shows single-agent antitumor efficacy in human SK-N-AS neuroblastoma and SW527 breast cancer xenograft models and even greater efficacy in combination with the chemotherapeutic agent docetaxel or an anti–vascular endothelial growth factor antibody. Antitumor activity of h10H5 is associated with decreased AKT activation and glucose uptake and a 316-gene transcription profile with significant changes involving DNA metabolic and cell cycle machineries. These data support the clinical testing of h10H5 as a biotherapeutic for IGF-IR-dependent human tumors and furthermore illustrate a new method of monitoring its activity noninvasively in vivo via 2-fluoro-2-deoxy-d-glucose-positron emission tomography imaging. [Mol Cancer Ther 2008;7(9):2599–608]
Antileukemia effects of xanthohumol in Bcr/Abl-transformed cells involve nuclear factor-κB and p53 modulation
Authors: Monteghirfo Stefano , Tosetti Francesca , Ambrosini Claudia , Stigliani Sara , Pozzi Sarah , Frassoni Francesco , Fassina Gianfranco , Soverini Simona , Albini Adriana , Ferrari Nicoletta
Published: September 2008

The oncogenic Bcr-Abl tyrosine kinase activates various signaling pathways including phosphoinositide 3-kinase/Akt and nuclear factor-κB that mediate proliferation, transformation, and apoptosis resistance in Bcr-Abl(+) myeloid leukemia cells. The hop flavonoid xanthohumol inhibits tumor growth by targeting the nuclear factor-κB and Akt pathways and angiogenesis. Here, we show that xanthohumol has in vitro activity against Bcr-Abl(+) cells and clinical samples and retained its cytotoxicity when imatinib mesylate–resistant K562 cells were examined. Xanthohumol inhibition of K562 cell viability was associated with induction of apoptosis, increased p21 and p53 expression, and decreased survivin levels. We show that xanthohumol strongly inhibited Bcr-Abl expression at both mRNA and protein levels and show that xanthohumol caused elevation of intracellular reactive oxygen species and that the antioxidant N-acetylcysteine blunted xanthohumol-induced events. Further, we observed that xanthohumol inhibits leukemia cell invasion, metalloprotease production, and adhesion to endothelial cells, potentially preventing in vivo life-threatening complications of leukostasis and tissue infiltration by leukemic cells. As structural mutations and/or gene amplification in Bcr-Abl can circumvent an otherwise potent anticancer drug such as imatinib, targeting Bcr-Abl expression as well as its kinase activity could be a novel additional therapeutic approach for the treatment of Bcr-Abl(+) myeloid leukemia. [Mol Cancer Ther 2008;7(9):2692–702]
SPC3042: a proapoptotic survivin inhibitor
Authors: Hansen Jens Bo , Fisker Niels , Westergaard Majken , Kjærulff Lene Sønderby , Hansen Henrik Frydenlund , Thrue Charlotte Albaek , Rosenbohm Christoph , Wissenbach Margit , Ørum Henrik , Koch Troels
Published: September 2008

The ability to regulate the cellular homeostasis of a higher organism through tight control of apoptosis and cell division is crucial for life. Dysregulation of these mechanisms is often associated with cancerous phenotypes in cells. Optimal cancer therapy is a fine balance between effective cancer cell killing and at the same time minimizing, or avoiding, damage to the surrounding healthy tissue. To obtain this, it is necessary to identify and inhibit molecular targets on which the cancer cells are strongly dependent. Survivin represents such a target, and it has been published previously that peptide vaccines, the small-molecule YM155, and the antisense molecule LY2181308/ISIS23722, via different mechanisms, have been used as survivin inhibitors. In this article, a new potent antisense inhibitor of survivin, SPC3042, is presented, and the properties of SPC3042 are compared with the previously published antisense drug, LY2181308/ISIS23722. SPC3042 is a 16-mer locked nucleic acid (LNA) oligonucleotide and designed as a fully phosphorothiolated gapmer containing 7 LNA nucleotides in the flanks. The LNA nucleotides in SPC3042 provide nuclease stability and higher potency for survivin mRNA inhibition compared with earlier generations of antisense reagents. It is shown that the down-regulation of survivin with SPC3042 leads to cell cycle arrest, pronounced cellular apoptosis, and down-regulation of Bcl-2. It is also shown that SPC3042 is a sensitizer of prostate cancer cells to Taxol treatment in vitro and in vivo. [Mol Cancer Ther 2008;7(9):2736–45]
Engineered anti-CD70 antibody-drug conjugate with increased therapeutic index
Authors: McDonagh Charlotte F. , Kim Kristine M. , Turcott Eileen , Brown Lindsay L. , Westendorf Lori , Feist Tiffany , Sussman Django , Stone Ivan , Anderson Martha , Miyamoto Jamie , Lyon Robert , Alley Stephen C. , Gerber Hans-Peter , Carter Paul J.
Published: September 2008

An anti-CD70 antibody conjugated to monomethylauristatin F (MMAF) via a valine-citrulline dipeptide containing linker has been shown previously to have potent antitumor activity in renal cell cancer xenograft studies. Here, we generated a panel of humanized anti-CD70 antibody IgG variants and conjugated them to MMAF to study the effect of isotype (IgG1, IgG2, and IgG4) and Fcγ receptor binding on antibody-drug conjugate properties. All IgG variants bound CD70+ 786-O cells with an apparent affinity of ∼1 nmol/L, and drug conjugation did not impair antigen binding. The parent anti-CD70 IgG1 bound to human FcγRI and FcγRIIIA V158 and mouse FcγRIV and this binding was not impaired by drug conjugation. In contrast, binding to these Fcγ receptors was greatly reduced or abolished in the variant, IgG1v1, containing the previously described mutations, E233P:L234V:L235A. All conjugates had potent cytotoxic activity against six different antigen-positive cancer cell lines in vitro with IC50 values of 30 to 540 pmol/L. The IgGv1 conjugate with MMAF displayed improved antitumor activity compared with other conjugates in 786-O and UMRC3 models of renal cell cancer and in the DBTRG05-MG glioblastoma model. All conjugates were tolerated to ≥40 mg/kg in mice. Thus, the IgG1v1 MMAF conjugate has an increased therapeutic index compared with the parent IgG1 conjugate. The improved antitumor activity of the IgG1v1 auristatin conjugates may relate to increased exposure as suggested by pharmacokinetic analysis. The strategy used here for enhancing the therapeutic index of antibody-drug conjugates is independent of the antigen-binding variable domains and potentially applicable to other antibodies. [Mol Cancer Ther 2008;7(9):2913–23]
Critical role of prostate apoptosis response-4 in determining the sensitivity of pancreatic cancer cells to small-molecule inhibitor-induced apoptosis
Authors: Azmi Asfar Sohail , Wang Zhiwei , Burikhanov Ravshan , Rangnekar Vivek M. , Wang Guoping , Chen Jianyong , Wang Shaomeng , Sarkar Fazlul H. , Mohammad Ramzi M.
Published: September 2008

Role of prostate apoptosis response-4 (PAR-4) has been well described in prostate cancer. However, its significance in other cancers has not been fully elucidated. For the current study, we selected four pancreatic cancer cell lines (BxPC-3, Colo-357, L3.6pl, and HPAC) that showed differential endogenous expression of PAR-4. We found that nonpeptidic small-molecule inhibitors (SMI) of Bcl-2 family proteins (apogossypolone and TW-37; 250 nmol/L and 1 μmol/L, respectively) could induce PAR-4-dependent inhibition of cell growth and induction of apoptosis. Sensitivity to apoptosis was directly related to the expression levels of PAR-4 (R = 0.92 and R2 = 0.95). Conversely, small interfering RNA against PAR-4 blocked apoptosis, confirming that PAR-4 is a key player in the apoptotic process. PAR-4 nuclear localization is considered a prerequisite for cells to undergo apoptosis, and we found that the treatment of Colo-357 and L3.6pl cells with 250 nmol/L SMI leads to nuclear localization of PAR-4 as confirmed by 4′,6-diamidino-2-phenylindole staining. In combination studies with gemcitabine, pretreatment with SMI leads to sensitization of Colo-357 cells to the growth-inhibitory and apoptotic action of a therapeutic drug, gemcitabine. In an in vivo setting, the maximum tolerated dose of TW-37 in xenograft of severe combined immunodeficient mice (40 mg/kg for three i.v. injections) led to significant tumor inhibition. Our results suggest that the observed antitumor activity of SMIs is mediated through a novel pathway involving induction of PAR-4. To our knowledge, this is the first study reporting SMI-mediated apoptosis involving PAR-4 in pancreatic cancer. [Mol Cancer Ther 2008;7(9):2884–93]
Hepatocyte Growth Factor Inhibits VEGF-Forkhead–Dependent Gene Expression in Endothelial Cells
Authors: Abid Md. Ruhul , Nadeau Robert J. , Spokes Katherine C. , Minami Takashi , Li Dan , Shih Shou-Ching , Aird William C.
Published: September 2008

Objective—

Recently, we reported that the forkhead transcription factor, FKHR/FOXO1, is required for vascular endothelial growth factor (VEGF)–mediated upregulation of a number of genes in endothelial cells. Here, we tested the hypothesis that hepatocyte growth factor (HGF), a potent activator of PI3K-Akt in endothelial cells, is capable of depleting the nucleus of FKHR/FOXO1 and thus inhibiting VEGF induction of this class of genes.

Methods and Results—

Incubation of human coronary artery endothelial cells with HGF induced prolonged PI3K/Akt-dependent phosphorylation and nuclear exclusion of FKHR/FOXO1. HGF-mediated inhibition of FKHR/FOXO1 activity resulted in secondary attenuation of VEGF-induced expression of FKHR/FOXO1-dependent genes including vascular cell adhesion molecule-1, manganese superoxide dismutase, endothelial specific molecule-1, CBP/p300 interacting transactivator with ED-rich tail-2, bone morphogenetic protein-2, matrix metalloproteinase (MMP)-10, and MGC5618. At a functional level, preincubation of HGF resulted in inhibition of VEGF-induced vascular cell adhesion molecule (VCAM)-1–mediated monocyte adhesion to endothelial cells. HGF-mediated inhibition of VEGF-inducible VCAM-1 expression and monocyte adhesion was reversed by overexpression of constitutively active phosphorylation-resistant triple mutant (TM)-FKHR.

Conclusion—

These findings suggest that physiological agonists of PI3K-Akt signaling pathway may modulate VEGF-FKHR/FOXO1–dependent gene expression in endothelial cells. The data underscore the importance of the “set point” of the endothelial cell when considering mechanisms of signal transduction.
The Wnt Antagonist Dickkopf-1 Mobilizes Vasculogenic Progenitor Cells via Activation of the Bone Marrow Endosteal Stem Cell Niche
Authors: Aicher Alexandra , Kollet Orit , Heeschen Christopher , Liebner Stefan , Urbich Carmen , Ihling Christian , Orlandi Alessia , Lapidot Tsvee , Zeiher Andreas M. , Dimmeler Stefanie
Published: September 2008

Therapeutic mobilization of vasculogenic progenitor cells is a novel strategy to enhance neovascularization for tissue repair. Prototypical mobilizing agents such as granulocyte colony-stimulating factor mobilize vasculogenic progenitor cells from the bone marrow concomitantly with inflammatory cells. In the bone marrow, mobilization is regulated in the stem cell niche, in which endosteal cells such as osteoblasts and osteoclasts play a key role. Because Wnt signaling regulates endosteal cells, we examined whether the Wnt signaling antagonist Dickkopf (Dkk)-1 is involved in the mobilization of vasculogenic progenitor cells. Using TOP-GAL transgenic mice to determine activation of β-catenin, we demonstrate that Dkk-1 regulates endosteal cells in the bone marrow stem cell niche and subsequently mobilizes vasculogenic and hematopoietic progenitors cells without concomitant mobilization of inflammatory neutrophils. The mobilization of vasculogenic progenitors required the presence of functionally active osteoclasts, as demonstrated in PTPε-deficient mice with defective osteoclast function. Mechanistically, Dkk-1 induced the osteoclast differentiation factor RANKL, which subsequently stimulated the release of the major bone-resorbing protease cathepsin K. Eventually, the Dkk-1–induced mobilization of bone marrow–derived vasculogenic progenitors enhanced neovascularization in Matrigel plugs. Thus, these data show that Dkk-1 is a mobilizer of vasculogenic progenitors but not of inflammatory cells, which could be of great clinical importance to enhance regenerative cell therapy.
Role of the ATP-Binding Cassette Transporter
Abcg2
in the Phenotype and Function of Cardiac Side Population Cells
Authors: Pfister Otmar , Oikonomopoulos Angelos , Sereti Konstantina-Ioanna , Sohn Regina L. , Cullen Darragh , Fine Gabriel C. , Mouquet Frédéric , Westerman Karen , Liao Ronglih
Published: September 2008

Recently, the side population (SP) phenotype has been introduced as a reliable marker to identify subpopulations of cells with stem/progenitor cell properties in various tissues. We and others have identified SP cells from postmitotic tissues, including adult myocardium, in which they have been suggested to contribute to cellular regeneration following injury. SP cells are identified and characterized by a unique efflux of Hoechst 33342 dye.
Abcg2
belongs to the ATP-binding cassette (ABC) transporter superfamily and constitutes the molecular basis for the dye efflux, hence the SP phenotype, in hematopoietic stem cells. Although
Abcg2
is also expressed in cardiac SP (cSP) cells, its role in regulating the SP phenotype and function of cSP cells is unknown. Herein, we demonstrate that regulation of the SP phenotype in cSP cells occurs in a dynamic, age-dependent fashion, with
Abcg2
as the molecular determinant of the cSP phenotype in the neonatal heart and another ABC transporter,
Mdr1
, as the main contributor to the SP phenotype in the adult heart. Using loss- and gain-of-function experiments, we find that
Abcg2
tightly regulates cell fate and function. Adult cSP cells isolated from mice with genetic ablation of
Abcg2
exhibit blunted proliferation capacity and augmented cell death. Conversely, overexpression of
Abcg2
is sufficient to enhance cell proliferation, although with a limitation of cardiomyogenic differentiation. In summary, for the first time, we reveal a functional role for
Abcg2
in modulating the proliferation, differentiation, and survival of adult cSP cells that goes beyond its distinct role in Hoechst dye efflux.
Activation of Na
+
/H
+
Exchanger 1 Is Sufficient to Generate Ca
2+
Signals That Induce Cardiac Hypertrophy and Heart Failure
Authors: Nakamura Tomoe Y. , Iwata Yuko , Arai Yuji , Komamura Kazuo , Wakabayashi Shigeo
Published: September 2008

Activation of the sarcolemmal Na
+
/H
+
exchanger (NHE)1 is increasingly documented as a process involved in cardiac hypertrophy and heart failure. However, whether NHE1 activation alone is sufficient to induce such remodeling remains unknown. We generated transgenic mice that overexpress a human NHE1 with high activity in hearts. The hearts of these mice developed cardiac hypertrophy, contractile dysfunction, and heart failure. In isolated transgenic myocytes, intracellular pH was elevated in Hepes buffer but not in physiological bicarbonate buffer, yet intracellular Na
+
concentrations were higher under both conditions. In addition, both diastolic and systolic Ca
2+
levels were increased as a consequence of Na
+
-induced Ca
2+
overload; this was accompanied by enhanced sarcoplasmic reticulum Ca
2+
loading via Ca
2+
/calmodulin-dependent protein kinase (CaMK)II-dependent phosphorylation of phospholamban. Negative force–frequency dependence was observed with preservation of high Ca
2+
, suggesting a decrease in myofibril Ca
2+
sensitivity. Furthermore, the Ca
2+
-dependent prohypertrophic molecules calcineurin and CaMKII were highly activated in transgenic hearts. These effects observed in vivo and in vitro were largely prevented by the NHE1 inhibitor cariporide. Interestingly, overexpression of NHE1 in neonatal rat ventricular myocytes induced cariporide-sensitive nuclear translocation of NFAT (nuclear factor of activated T cells) and nuclear export of histone deacetylase 4, suggesting that increased Na
+
/H
+
exchange activity can alter hypertrophy-associated gene expression. However, in transgenic myocytes, contrary to exclusive translocation of histone deacetylase 4, NFAT only partially translocated to nucleus, possibly because of marked activation of p38, a negative regulator of NFAT signaling. We conclude that activation of NHE1 is sufficient to initiate cardiac hypertrophy and heart failure mainly through activation of CaMKII–histone deacetylase pathway.
Bestrophin-3 (Vitelliform Macular Dystrophy 2–Like 3 Protein) Is Essential for the cGMP-Dependent Calcium-Activated Chloride Conductance in Vascular Smooth Muscle Cells
Authors: Matchkov Vladimir V. , Larsen Per , Bouzinova Elena V. , Rojek Aleksandra , Boedtkjer Donna M. Briggs , Golubinskaya Veronika , Pedersen Finn Skou , Aalkjær Christian , Nilsson Holger
Published: September 2008

Although the biophysical fingerprints (ion selectivity, voltage-dependence, kinetics, etc) of Ca
2+
-activated Cl
−
currents are well established, their molecular identity is still controversial. Several molecular candidates have been suggested; however, none of them has been fully accepted. We have recently characterized a cGMP-dependent Ca
2+
-activated Cl
−
current with unique characteristics in smooth muscle cells. This novel current has been shown to coexist with a “classic” (cGMP-independent) Ca
2+
-activated Cl
−
current and to have characteristics distinct from those previously known for Ca
2+
-activated Cl
−
currents. Here, we suggest that a bestrophin, a product of the
Best
gene family, is responsible for the cGMP-dependent Ca
2+
-activated Cl
−
current based on similarities between the membrane currents produced by heterologous expressions of bestrophins and the cGMP-dependent Ca
2+
-activated Cl
−
current. This is supported by similarities in the distribution pattern of the cGMP-dependent Ca
2+
-activated Cl
−
current and bestrophin-3 (the product of
Best-3
gene) expression in different smooth muscle. Furthermore, downregulation of
Best-3
gene expression with small interfering RNA both in cultured cells and in vascular smooth muscle cells in vivo was associated with a significant reduction of the cGMP-dependent Ca
2+
-activated Cl
−
current, whereas the magnitude of the classic Ca
2+
-activated Cl
−
current was not affected. The majority of previous suggestions that bestrophins are a new Cl
−
channel family were based on heterologous expression in cell culture studies. Our present results demonstrate that at least 1 family member, bestrophin-3, is essential for a well-defined endogenous Ca
2+
-activated Cl
−
current in smooth muscles in the intact vascular wall.
Reactive Oxygen Species Production in Energized Cardiac Mitochondria During Hypoxia/Reoxygenation
Authors: Korge Paavo , Ping Peipei , Weiss James N.
Published: September 2008

Mitochondria are an important source of reactive oxygen species (ROS), implicated in ischemia/reperfusion injury. When isolated from ischemic myocardium, mitochondria demonstrate increased ROS production as a result of damage to electron transport complexes. To investigate the mechanisms, we studied effects of hypoxia/reoxygenation on ROS production by isolated energized heart mitochondria. ROS production, tracked using Fe
2+
-catalyzed, H
2
O
2
-dependent H
2
DCF oxidation or Amplex Red, was similar during normoxia and hypoxia but markedly increased during reoxygenation, in proportion to the duration of hypoxia. In contrast, if mitochondria were rapidly converted from normoxia to near-anoxia ([O
2
], <1 μmol/L), the increase in H
2
DCF oxidation rate during reoxygenation was markedly blunted. To elicit the robust increase in H
2
DCF oxidation rate during reoxygenation, hypoxia had to be severe enough to cause partial, but not complete, respiratory chain inhibition (as shown by partial dissipation of membrane potential and increased NADH autofluorescence). Consistent with its cardioprotective actions, nitric oxide (

O) abrogated increased H
2
DCF oxidation under these conditions, as well as attenuating ROS-induced increases in matrix [Fe
2+
] and aconitase inhibition caused by antimycin. Collectively, these results suggest that (1) hypoxia that is sufficient to cause partial respiratory inhibition is more damaging to mitochondria than near-anoxia; and (2)

O suppresses ROS-induced damage to electron transport complexes, probably by forming

O-Fe
2+
complexes in the presence of glutathione, which inhibit hydroxyl radical formation.
Physiological Properties of hERG 1a/1b Heteromeric Currents and a hERG 1b-Specific Mutation Associated With Long-QT Syndrome
Authors: Sale Harinath , Wang Jinling , O'Hara Thomas J. , Tester David J. , Phartiyal Pallavi , He Jia-Qiang , Rudy Yoram , Ackerman Michael J. , Robertson Gail A.
Published: September 2008

CardiacIKris a critical repolarizing current in the heart and a target for inherited and acquired long-QT syndrome (LQTS). Biochemical and functional studies have demonstrated thatIKrchannels are heteromers composed of both hERG 1a and 1b subunits, yet our current understanding ofIKrfunctional properties derives primarily from studies of homooligomers of the original hERG 1a isolate. Here, we examine currents produced by hERG 1a and 1a/1b channels expressed in HEK-293 cells at near-physiological temperatures. We find that heteromeric hERG 1a/1b currents are much larger than hERG 1a currents and conduct 80% more charge during an action potential. This surprising difference corresponds to a 2-fold increase in the apparent rates of activation and recovery from inactivation, thus reducing rectification and facilitating current rebound during repolarization. Kinetic modeling shows these gating differences account quantitatively for the differences in current amplitude between the 2 channel types. Drug sensitivity was also different. Compared to homomeric 1a channels, heteromeric 1a/1b channels were inhibited by E-4031 with a slower time course and a corresponding 4-fold shift in the IC50. The importance of hERG 1b in vivo is supported by the identification of a 1b-specific A8V missense mutation in 1/269 unrelated genotype-negative LQTS patients that was absent in 400 control alleles. Mutant 1bA8V expressed alone or with hERG 1a in HEK-293 cells dramatically reduced 1b protein levels. Thus, mutations specifically disrupting hERG 1b function are expected to reduce cardiacIKrand enhance drug sensitivity, and represent a potential mechanism underlying inherited or acquired LQTS.
The Hybrid Story of Balaam (Numbers 22–24): Theology for the Diaspora in the Torah
Authors: Sals Ulrike
Published: September 2008

The strange character of Numbers 22–24 as a story about foreigners and their attempts to rule YHWH can successfully be read with Homi Bhabha's concept of hybridity and Gayatri Spivak's subaltern. Focusing on the characters' relationships in this text, Balak is the hegemon and Balaam the subaltern, and this constitutes much of their communicational failures. The donkey's episode serves as a lesson for the reader as well as for Balaam who is the hegemon in this case: he learns—as Balak does not—that God is the real worldly and 'wordly' hegemon. This monotheistic message is explained to the Judaean readers/listeners through non-Judean protagonists. Many details point to an origin of the final text in a reception of the deuteronomistic YHWH/Assur/Israel constellation and theology in Persian times.
Moses and Abraham Go Arctic
Authors: Petterson Christina
Published: September 2008

This paper reads the Gospel of John as expounded by Musa W. Dube in her article 'Savior of the World but not of This World: A Post-Colonial Reading of Spatial Construction in John' alongside the religious situation in contemporary Greenland, itself an often ignored example of the dilemmas of colonisation and postcolonialism. Tensions between the Danish Lutheran State Church and anti-Danish members of the indigenous Inuit populations over the place of Christianity in contemporary Inuit identity are analogous to the tension in John's gospel over who can claim to be Israel. In making this comparison, I hope not to exemplify what David Jobling warns us about: "Simple links between biblical and current situations, whether they leave the Bible looking good or bad, convey no lasting benefit." I seek to overcome the theoretical problems inherent in blindly adopting Dube's intertextual methods by employing Jonathan Z. Smith's observations on comparison. This in turn poses another range of problems about identity and method for readers as well as for the text which will be outlined here. Both the New Testament and the contemporary situation reveal the complexity of identities which simple categories of 'coloniser' and 'colonised' do not encompass.
Development of a Zero-Dimensional Mesoscale Thermal Model for Urban Climate
Authors: Silva Humberto R. , Bhardwaj Rahul , Phelan Patrick E. , Golden Jay S. , Grossman-Clarke Susanne
Published: September 2008

A simple energy balance model is created for use in developing mitigation strategies for the urban heat island effect. The model is initially applied to the city of Phoenix, Arizona. There are six primary contributions to the overall energy balance: incident solar radiation, anthropogenic heat input, conduction heat loss, outgoing evapotranspiration, outgoing convection, and outgoing emitted radiation. Meteorological data are input to the model, which then computes an urban characteristic temperature at a calculated time step for a specified time range. The model temperature is shown to have the same periodic behavior as the experimentally measured air temperatures. Predicted temperature changes, caused by increasing the average urban albedo, agree within 0.1°C with comparable maximum surface temperature predictions from the fifth-generation Pennsylvania State University–National Center for Atmospheric Research Mesoscale Model (MM5). The present model, while maintaining valid energy-balance physics, allows users to quickly and easily predict the relative effects of urban heat island mitigation measures. Representative mitigation strategies, namely changes in average albedo and long-wavelength emissivity are presented here. Increasing the albedo leads to the greater reduction in daytime maximum temperatures; increasing the emissivity leads to a greater reduction in nighttime minimum temperatures.
A Wind Tunnel Study on the Shape, Oscillation, and Internal Circulation of Large Raindrops with Sizes between 2.5 and 7.5 mm
Authors: Szakáll Miklós , Diehl Karoline , Mitra Subir K. , Borrmann Stephan
Published: September 2008

Precipitation prediction using weather radars requires detailed knowledge of the shape parameters of raindrops falling at their terminal velocities in air. Because the raindrops undergo oscillation, the most important shape parameters from the radar prediction point of view are the equilibrium drop shape, the time-averaged axis ratio, and the oscillation frequency. These parameters for individual water drops with equivalent diameter from 2.5 to 7.5 mm were investigated in a vertical wind tunnel using high-speed video imaging. A very good agreement was found between the measured and the theoretically determined raindrop shape calculated by a force balance model. A new method was developed to determine the equivalent drop diameter with the help of the oscillation frequency. The drop size determination by means of the frequency method was found to be three times more precise than by volumetric methods. The time-averaged axis ratio was found to be equal to the equilibrium axis ratio in the investigated raindrop size range. The analysis of the oscillation frequency of the raindrops revealed that the drops undergo multimode oscillations and are oscillating in a transverse mode in addition to an axisymmetric oblate–prolate mode. Experiments are included in which the internal circulation associated with drop oscillation was investigated and compared to theory.
On the Use of Satellite Altimeter Data in Argo Quality Control
Authors: Guinehut Stephanie , Coatanoan Christine , Dhomps Anne-Lise , Le Traon Pierre-Yves , Larnicol Gilles
Published: September 2008

Satellite altimeter measurements are used to check the quality of the Argo profiling floats time series. The method compares collocated sea level anomalies from altimeter measurements and dynamic height anomalies calculated from Argo temperature and salinity profiles for each Argo float time series. Different kinds of anomalies (sensor drift, bias, spikes, etc.) have been identified on some real-time but also delayed-mode Argo floats. About 4% of the floats should probably not be used until they are carefully checked and reprocessed by the principal investigators (PIs). The method appears to be very complementary to the existing quality control checks performed in real time or delayed mode. It could also be used to quantify the impact of the adjustments made in delayed mode on the pressure, temperature, and salinity fields.
Diabatically Induced Secondary Flows in Tropical Cyclones. Part II: Periodic Forcing
Authors: Willoughby Hugh E.
Published: September 2008

The linearized equation for the time-varying, axially symmetric circumferential component of the vorticity in a hurricane-like vortex closely resembles the classical Sawyer–Eliassen equation for the quasi-steady, diabatically induced secondary-flow streamfunction. The salient difference lies in the coefficients of the second partial derivatives with respect to radius and height. In the Sawyer–Eliassen equation, they are the squares of the buoyancy and isobaric local inertia frequencies; in the circumferential vorticity equation they are the differences between these quantities and the square of the frequency with which the imposed forcing varies. The coefficient of the mixed partial derivative with respect to radius and height is the same in both equations. Thus, for low frequencies the response to periodic forcing is a slowly varying analog to steady Sawyer–Eliassen solutions. For high frequencies, the solutions are radially propagating inertia-buoyancy waves. Since the local inertia frequency, which approximately defines the boundary between quasi-steady and propagating solutions, decreases with radius, quasi-steady solutions in the vortex core transform into radiating ones far from the center. Periodic forcing will always lead to some wave radiation to the storm environment unless the period of the forcing is longer than a half-pendulum day.