bluuebunny/crossref_metadata_2025 huggingface dataset:
Both Complement- and Fibrinogen-Dependent Mechanisms Contribute to Platelet Aggregation Mediated by
Staphylococcus aureus
Clumping Factor B
Authors: Miajlovic Helen , Loughman Anthony , Brennan Marian , Cox Dermot , Foster Timothy J.
Published: April 2007

Staphylococcus aureus
can stimulate activation and aggregation of platelets, which are thought to be factors in the development of infective endocarditis. Previous studies have identified clumping factor A (ClfA) and fibronectin binding proteins A and B (FnBPA and FnBPB) as potent platelet aggregators. These proteins are able to stimulate rapid platelet aggregation by either a fibrinogen- or a fibronectin-dependent process which also requires antibodies specific to each protein. Slower aggregation has been seen in other systems where specific fibrinogen binding ligands are absent and platelet aggregation is mediated by complement and specific antibodies. Bacteria expressing ClfB aggregate platelets with a longer lag time than ClfA or FnBPA and FnBPB. In order to investigate whether ClfB causes platelet aggregation in a complement- or fibrinogen-dependent manner, a non-fibrinogen-binding mutant of ClfB (ClfB Q235A) was constructed.
Lactococcus lactis
expressing ClfB Q235A was able to stimulate platelet aggregation in platelet-rich plasma without a significant increase in lag time. The requirements for platelet aggregation were investigated using gel-filtered platelets. Fibrinogen and specific anti-ClfB antibodies were found to be sufficient to allow platelet aggregation mediated by the wild-type ClfB protein. It seems that ClfB causes platelet aggregation by a fibrinogen-dependent mechanism. The non-fibrinogen-binding ClfB mutant was unable to stimulate platelet aggregation under these conditions. However, bacteria expressing ClfB Q235A caused platelet aggregation in a complement-dependent manner which required specific anti-ClfB antibodies.
Virulence Potential of
Ehrlichia chaffeensis
Strains of Distinct Genome Sequences
Authors: Miura Koshiro , Rikihisa Yasuko
Published: April 2007

Human monocytic ehrlichiosis, one of the most frequent life-threatening tick-borne zoonoses, is caused by
Ehrlichia chaffeensis
that lacks endotoxin and peptidoglycan. While sequence polymorphisms in several genes in
E. chaffeensis
strains have been reported, global genomic divergence and biological differences among strains are unknown. The objectives of the present study were to compare the genome sequences of strains of
E. chaffeensis
and to examine the virulence potentials of the strains with defined genome sequences. Genomic DNA was extracted from purified
E. chaffeensis
strains Wakulla and Liberty, and comparative genome hybridization was performed using a densely tiled microarray of 147,027 chromosome positions of the
E. chaffeensis
strain Arkansas genome. The results revealed that 4,663 and 5,325 positions in the chromosomes of strains Wakulla and Liberty, respectively, were different from those in the chromosome of strain Arkansas, including three common major polymorphic chromosomal regions. Of various functional categories, the differences were most concentrated in genes predicted to encode cell envelope proteins. Of all the open reading frames (ORFs), 21
omp-1
(p28 gene) paralogs, nine genes encoding hypothetical proteins, two genes encoding ankyrin repeat proteins, and
hemE
contained the most differences. Several highly polymorphic ORFs were confirmed by sequencing. When the
E. chaffeensis
strains were inoculated into severe combined immunodeficiency mice, the order of the severity of clinical signs and the bacterial burden detected in mice was Wakulla > Liberty > Arkansas. Severe diffuse inflammation and granulomatous inflammation were evident in the livers of mice infected with strains Wakulla and Arkansas, respectively, but not in the livers of mice infected with strain Liberty. These results revealed distinct virulence phenotypes of
E. chaffeensis
strains with defined genome sequences.
Oxidative Stress and Diabetic Retinopathy
Authors: Kowluru Renu A. , Chan Pooi-See
Published: April 2007

Oxygen metabolism is essential for sustaining aerobic life, and normal cellular homeostasis works on a fine balance between the formation and elimination of reactive oxygen species (ROS). Oxidative stress, a cytopathic consequence of excessive production of ROS and the suppression of ROS removal by antioxidant defense system, is implicated in the development of many diseases, including Alzheimer′s disease, and diabetes and its complications. Retinopathy, a debilitating microvascular complication of diabetes, is the leading cause of acquired blindness in developed countries. Many diabetes‐induced metabolic abnormalities are implicated in its development, and appear to be influenced by elevated oxidative stress; however the exact mechanism of its development remains elusive. Increased superoxide concentration is considered as a causal link between elevated glucose and the other metabolic abnormalities important in the pathogenesis of diabetic complications. Animal studies have shown that antioxidants have beneficial effects on the development of retinopathy, but the results from very limited clinical trials are somewhat ambiguous. Although antioxidants are being used for other chronic diseases, controlled clinical trials are warranted to investigate potential beneficial effects of antioxidants in the development of retinopathy in diabetic patients.
Motion Control and Implementation for an AC Servomotor System
Authors: Dülger L. Canan , Kireçci Ali
Published: April 2007

This paper presents a study on trajectory tracking problem for an AC synchronous servomotor. A mathematical model for the system including AC synchronous servomotor, gearbox, and a load is developed to examine the systems dynamic behavior. The system is controlled by a traditional PID (proportional + integral + derivative) controller. The required values for the controller settings are found experimentally. Different motion profiles are designed, and trapezoidal ones are implemented. Thus, the experimental validation of the model is achieved using the experimental setup. The simulation and experimental results are presented. The tracking performance of an AC servomotor system is illustrated with proposed PID controller.
Inhibition of Advanced Glycation and Absence of Galectin‐3 Prevent Blood‐Retinal Barrier Dysfunction during Short‐Term Diabetes
Authors: Canning Paul , Glenn Josephine V. , Hsu Daniel K. , Liu Fu-Tong , Gardiner Tom A. , Stitt Alan W.
Published: April 2007

Breakdown of the inner blood‐retinal barrier (iBRB) occurs early in diabetes and is central to the development of sight‐threatening diabetic macular edema (DME) as retinopathy progresses. In the current study, we examined how advanced glycation end products (AGEs) forming early in diabetes could modulate vasopermeability factor expression in the diabetic retina and alter inter‐endothelial cell tight junction (TJ) integrity leading to iBRB dysfunction. We also investigated the potential for an AGE inhibitor to prevent this acute pathology and examined a role of the AGE‐binding protein galectin‐3 (Gal‐3) in AGE‐mediated cell retinal pathophysiology. Diabetes was induced in C57/BL6 wild‐type (WT) mice and in Gal‐3−/− transgenic mice. Blood glucose was monitored and AGE levels were quantified by ELISA and immunohistochemistry. The diabetic groups were subdivided, and one group was treated with the AGE‐inhibitor pyridoxamine (PM) while separate groups of WT and Gal‐3−/− mice were maintained as nondiabetic controls. iBRB integrity was assessed by Evans blue assay alongside visualisation of TJ protein complexes via occludin‐1 immunolocalization in retinal flat mounts. Retinal expression levels of the vasopermeability factor VEGF were quantified using real‐time RT‐PCR and ELISA. WT diabetic mice showed significant AGE ‐immunoreactivity in the retinal microvasculature and also showed significant iBRB breakdown (P < .005). These diabetics had higher VEGF mRNA and protein expression in comparison to controls (P < .01). PM‐treated diabetics had normal iBRB function and significantly reduced diabetes‐mediated VEGF expression. Diabetic retinal vessels showed disrupted TJ integrity when compared to controls, while PM‐treated diabetics demonstrated near‐normal configuration. Gal‐3−/− mice showed significantly less diabetes‐mediated iBRB dysfunction, junctional disruption, and VEGF expression changes than their WT counterparts. The data suggests an AGE‐mediated disruption of iBRB via upregulation of VEGF in the diabetic retina, possibly modulating disruption of TJ integrity, even after acute diabetes. Prevention of AGE formation or genetic deletion of Gal‐3 can effectively prevent these acute diabetic retinopathy changes.
Effect of L‐Carnitine on Skeletal Muscle Lipids and Oxidative Stress in Rats Fed High‐Fructose Diet
Authors: Rajasekar Panchamoorthy , Anuradha Carani Venkatraman
Published: April 2007

There is evidence that high‐fructose diet induces insulin resistance, alterations in lipid metabolism, and oxidative stress in rat tissues. The purpose of this study was to evaluate the effect of L‐carnitine (CAR) on lipid accumulation and peroxidative damage in skeletal muscle of rats fed high‐fructose diet. Fructose‐fed animals (60 g/100 g diet) displayed decreased glucose/insulin (G/I) ratio and insulin sensitivity index (ISI0,120) indicating the development of insulin resistance. Rats showed alterations in the levels of triglycerides, free fatty acids, cholesterol, and phospholipids in skeletal muscle. The condition was associated with oxidative stress as evidenced by the accumulation of lipid peroxidation products, protein carbonyls, and aldehydes along with depletion of both enzymic and nonenzymic antioxidants. Simultaneous intraperitoneal administration of CAR (300 mg/kg/day) to fructose‐fed rats alleviated the effects of fructose. These rats showed near‐normal levels of the parameters studied. The effects of CAR in this model suggest that CAR supplementation may have some benefits in patients suffering from insulin resistance.
Voltage-Mode All-Pass Filters Including Minimum Component Count Circuits
Authors: Maheshwari Sudhanshu
Published: April 2007

This paper presents two new first-order voltage-mode all-pass filters using a single-current differencing buffered amplifier and four passive components. Each circuit is compatible to a current-controlled current differencing buffered amplifier with only two passive elements, thus resulting in two more circuits, which employ a capacitor, a resistor, and an active element, thus using a minimum of active and passive component counts. The proposed circuits possess low output impedance, and hence can be easily cascaded for voltage-mode systems. PSPICE simulation results are given to confirm the theory.
Overexpressed Cyclophilin A in Cancer Cells Renders Resistance to Hypoxia- and Cisplatin-Induced Cell Death
Authors: Choi Kyu Jin , Piao Yu Ji , Lim Min Jin , Kim Jin Hwan , Ha Joohun , Choe Wonchae , Kim Sung Soo
Published: April 2007

Cyclophilin A (CypA) has been reported to be overexpressed in cancer cells, especially in solid tumors. To determine the role of CypA in tumorigenesis, we investigated the induction of CypA as well as the role it plays in cancer cells. Here, we have shown that induction of CypA is associated with hypoxia in a variety of cells, including DU145 human prostate cancer cell line. Our analysis of the CypA promoter clearly showed that CypA up-regulation is mediated by hypoxia-inducible factor-1α transcription factor. Interestingly, overexpression of CypA prevented hypoxia- and cisplatin-induced apoptosis, and this was associated with the suppression of reactive oxygen species generation and depolarization of mitochondrial membrane potential, whereas small interfering RNA–based CypA knockdown aggravated these factors. These results suggest that CypA is important in tumorigenesis, especially in tumor apoptosis. [Cancer Res 2007;67(8):3654–62]
M3 Muscarinic Receptor Antagonists Inhibit Small Cell Lung Carcinoma Growth and Mitogen-Activated Protein Kinase Phosphorylation Induced by Acetylcholine Secretion
Authors: Song Pingfang , Sekhon Harmanjatinder S. , Lu Allison , Arredondo Juan , Sauer David , Gravett Courtney , Mark Gregory P. , Grando Sergei A. , Spindel Eliot R.
Published: April 2007

The importance of acetylcholine as a neurotransmitter in the nervous system is well established, but little is yet known about its recently described role as an autocrine and paracrine hormone in a wide variety of nonneuronal cells. Consistent with the expression of acetylcholine in normal lung, small cell lung carcinoma (SCLC) synthesize and secrete acetylcholine, which acts as an autocrine growth factor through both nicotinic and muscarinic cholinergic mechanisms. The purpose of this study was to determine if interruption of autocrine muscarinic cholinergic signaling has potential to inhibit SCLC growth. Muscarinic receptor (mAChR) agonists caused concentration-dependent increases in intracellular calcium and mitogen-activated protein kinase (MAPK) and Akt phosphorylation in SCLC cell lines. The inhibitory potency of mAChR subtype–selective antagonists and small interfering RNAs (siRNAs) on acetylcholine-increased intracellular calcium and MAPK and Akt phosphorylation was consistent with mediation by M3 mAChR (M3R). Consistent with autocrine acetylcholine secretion stimulating MAPK and Akt phosphorylation, M3R antagonists and M3R siRNAs alone also caused a decrease in basal levels of MAPK and Akt phosphorylation in SCLC cell lines. Treatment of SCLC cells with M3R antagonists inhibited cell growth both in vitro and in vivo and also decreased MAPK phosphorylation in tumors in nude mice in vivo. Immunohistochemical staining of SCLC and additional cancer types showed frequent coexpression of acetylcholine and M3R. These findings suggest that M3R antagonists may be useful adjuvants for treatment of SCLC and, potentially, other cancers. [Cancer Res 2007;67(8):3936–44]
Selective Down-Regulation of Glioma-Associated Oncogene 2 Inhibits the Proliferation of Hepatocellular Carcinoma Cells
Authors: Kim Youngsoo , Yoon Joon Won , Xiao Xiaokun , Dean Nicholas M. , Monia Brett P. , Marcusson Eric G.
Published: April 2007

The sonic hedgehog (Shh) pathway contributes to the initiation and progression of tumors with various origins when aberrantly activated. In this study, we investigated if the Shh pathway is important for the proliferation of hepatocellular carcinoma (HCC) cells and also began to identify which components of the pathway play a pivotal role in the biology of HCC. Expression levels of components in the pathway were measured, and glioma-associated oncogene (Gli) 2 levels were found to be considerably higher in human HCC lines compared with normal liver. Gli2 levels were also higher in tumor tissue from HCC patients compared with normal liver. Antisense oligonucleotides (ASO) were used to specifically down-regulate Gli2, and this led to decreased proliferation of various HCC cell lines. However, inhibition of Gli1 and Gli3 with ASOs did not decrease proliferation in most HCC cell lines and inhibitors targeting the upstream components of the pathway, including smoothened (Smo), displayed antiproliferative effects in only a subset of HCC cell lines. Moreover, in cancer cells harboring Smo mutations or unresponsive to the Smo inhibitor 3-keto-N-aminoethylaminoethylcaproyldihydrocinnamoyl cyclopamine, the Gli2 ASO was still able to inhibit proliferation. The importance of Gli2 in HCC proliferation was further confirmed by the changes in expression levels of genes, such as Bcl-2, c-Myc, and p27, following suppression of Gli2 expression. Taken together, these results suggest that, among the Gli transcription factors, Gli2 plays a predominant role in the proliferation of HCC cells and the suppression of Gli2 expression may provide a useful therapeutic option for the treatment of HCC. [Cancer Res 2007;67(8):3583–93]
Mechanism of Action of the Microtubule-Targeted Antimitotic Depsipeptide Tasidotin (Formerly ILX651) and Its Major Metabolite Tasidotin C-Carboxylate
Authors: Ray Anasuya , Okouneva Tatiana , Manna Tapas , Miller Herbert P. , Schmid Steven , Arthaud Larry , Luduena Richard , Jordan Mary Ann , Wilson Leslie
Published: April 2007

Tasidotin (ILX-651), an orally active synthetic microtubule-targeted derivative of the marine depsipeptide dolastatin-15, is currently undergoing clinical evaluation for cancer treatment. Tasidotin inhibited proliferation of MCF7/GFP breast cancer cells with an IC50 of 63 nmol/L and inhibited mitosis with an IC50 of 72 nmol/L in the absence of detectable effects on spindle microtubule polymer mass. Tasidotin inhibited the polymerization of purified tubulin into microtubules weakly (IC50 ∼ 30 μmol/L). However, it strongly suppressed the dynamic instability behavior of the microtubules at their plus ends at concentrations ∼5 to 10 times below those required to inhibit polymerization. Its major actions were to reduce the shortening rate, the switching frequency from growth to shortening (catastrophe frequency), and the fraction of time the microtubules grew. In contrast with all other microtubule-targeted drugs thus far examined that can inhibit polymerization, tasidotin did not inhibit the growth rate. In contrast to stabilizing plus ends, tasidotin enhanced microtubule dynamic instability at minus ends, increasing the shortening length, the fraction of time the microtubules shortened, and the catastrophe frequency and reducing the rescue frequency. Tasidotin C-carboxylate, the major intracellular metabolite of tasidotin, altered dynamic instability of purified microtubules in a qualitatively similar manner to tasidotin but was 10 to 30 times more potent. The results suggest that the principal mechanism by which tasidotin inhibits cell proliferation is by suppressing spindle microtubule dynamics. Tasidotin may be a relatively weak prodrug for the functionally active tasidotin C-carboxylate. [Cancer Res 2007;67(8):3767–76]
Therapeutic Effect of Rapamycin on Gallbladder Cancer in a Transgenic Mouse Model
Authors: Wu Qi , Kiguchi Kaoru , Kawamoto Toru , Ajiki Tetsuo , Traag Jeanine , Carbajal Steve , Ruffino Lynnsie , Thames Howard , Wistuba Ignacio , Thomas Melanie , Vasquez Karen M. , DiGiovanni John
Published: April 2007

The macrolide fungicide rapamycin has shown significant antiproliferative action toward a variety of tumor types. In this study, we used BK5.erbB2 transgenic mice as an animal model to examine the therapeutic effect of rapamycin as a potential treatment for gallbladder cancer. Homozygous BK5.erbB2 mice overexpressing the wild-type rat erbB2 gene in basal epithelial cells of the gallbladder have an ∼70% incidence of gallbladder adenocarcinoma by 2 to 3 months of age. Groups of mice (∼2–3 months of age) were treated with rapamycin by i.p. injection (once daily for 14 days) and then sacrificed 24 h after the last treatment. Rapamycin significantly reduced the incidence and severity of gallbladder carcinoma in BK5.erbB2 mice in a dose-dependent manner. Tumors responsive to treatment exhibited a higher number of apoptotic cells. Furthermore, rapamycin treatment led to decreased levels of phosphorylated p70 S6 kinase (Thr389) in gallbladder tissue as assessed by both Western blot and immunofluorescence analyses. Finally, immunofluorescence staining revealed elevated phosphorylated Akt (Ser473) and phosphorylated mammalian target of rapamycin (mTOR; Ser2448) in human gallbladder cancer compared with normal gallbladder tissue. Based on our results using a novel genetically engineered mouse model and the fact that the Akt/mTOR pathway is activated in human gallbladder cancer, rapamycin and related drugs may be effective therapeutic agents for the treatment of human gallbladder cancer. [Cancer Res 2007;67(8):3794–800]
Src Phosphorylates Tyr284 in TGF-β Type II Receptor and Regulates TGF-β Stimulation of p38 MAPK during Breast Cancer Cell Proliferation and Invasion
Authors: Galliher Amy J. , Schiemann William P.
Published: April 2007

Genetic and epigenetic events often negate the cytostatic function of transforming growth factor-β (TGF-β) in mammary epithelial cells (MEC), which ultimately enables malignant MECs to proliferate, invade, and metastasize when stimulated by TGF-β. The molecular mechanisms underlying this phenotypic conversion of TGF-β function during mammary tumorigenesis remain poorly defined. We previously established αvβ3 integrin and Src as essential mediators of mitogen-activated protein kinase (MAPK) activation, invasion, and epithelial-to-mesenchymal transition stimulated by TGF-β in normal and malignant MECs. Mechanistically, β3 integrin interacted physically with the TGF-β type II receptor (TβR-II), leading to its tyrosine phosphorylation by Src and the initiation of oncogenic signaling by TGF-β. We now show herein that Src phosphorylated TβR-II on Y284 both in vitro and in vivo. Interestingly, although the expression of Y284F-TβR-II mutants in breast cancer cells had no effect on TGF-β stimulation of Smad2/3, this TβR-II mutant completely abrogated p38 MAPK activation by TGF-β. Accordingly, Src-mediated phosphorylation of Y284 coordinated the docking of the SH2 domains of growth factor receptor binding protein 2 (Grb2) and Src homology domain 2 containing (Shc) TβR-II, thereby associating these adapter proteins to MAPK activation by TGF-β. Importantly, Y284F-TβR-II mutants also abrogated breast cancer cell invasion induced by αvβ3 integrin and TGF-β as well as partially restored their cytostatic response to TGF-β. Our findings have identified a novel αvβ3 integrin/Src/Y284/TβR-II signaling axis that promotes oncogenic signaling by TGF-β in malignant MECs and suggest that antagonizing this signaling axis may one day prove beneficial in treating patients with metastatic breast cancers. [Cancer Res 2007;67(8):3752–8]
Identification of Their Epitope Reveals the Structural Basis for the Mechanism of Action of the Immunosuppressive Antibodies Basiliximab and Daclizumab
Authors: Binder Mascha , Vögtle Friederike-Nora , Michelfelder Stefan , Müller Fabian , Illerhaus Gerald , Sundararajan Sangeeth , Mertelsmann Roland , Trepel Martin
Published: April 2007

Interleukin-2 (IL-2) and its receptor (IL-2R) play a major role in cellular immunity. The monoclonal antibodies basiliximab and daclizumab directed against the IL-2R subunit CD25 are widely used to prevent graft or host rejection after allogeneic tissue transplantation. Although these antibodies have been used for this purpose for many years, their common epitope within the CD25 protein is unknown. We screened a random phage display library to isolate peptides specifically binding to basiliximab. A striking amino acid sequence motif was enriched. This motif is homologous to the peptide ERIYHFV comprising amino acid positions 116 to 122 within the extracellular domain of CD25, suggesting that this is the basiliximab epitope. Basiliximab and daclizumab binding of selected phage was specific, as no binding was observed to isotype antibody controls. Phage binding could be inhibited by the cognate peptide. In cells expressing mutant CD25, binding of basiliximab was abolished when two or more amino acids of the suspected epitope were changed. In contrast, basiliximab binding remained unaffected in cells expressing CD25 versions with mutations outside this epitope. We therefore conclude that the (116)ERIYHFV(122) string within CD25 is the epitope recognized by basiliximab and daclizumab. This epitope overlaps with the interaction site of CD25 and IL-2, thus revealing the structural basis for the inhibition of IL-2R binding by this class of immunosuppressive antibodies. [Cancer Res 2007;67(8):3518–23]
P21-Activated Protein Kinase Is Overexpressed in Hepatocellular Carcinoma and Enhances Cancer Metastasis Involving c-Jun NH2-Terminal Kinase Activation and Paxillin Phosphorylation
Authors: Ching Yick-Pang , Leong Veronica Y.L. , Lee Man-Fong , Xu Hai-Tao , Jin Dong-Yan , Ng Irene Oi-Lin
Published: April 2007

Hepatocellular carcinoma (HCC) is one of the major malignancies in the world. The prognosis of HCC is poor, due to frequent intrahepatic metastasis and tumor recurrence. P21-activated protein kinase (Pak1), a main downstream effector of small Rho GTPases, Rac1 and Cdc42, plays an important role in the regulation of cell morphogenesis, motility, mitosis, and angiogenesis. Here, we show that Pak1 gene was overexpressed in human HCCs. Overexpression of Pak1 in human HCCs was associated with more aggressive tumor behavior in terms of more metastatic phenotype and more advanced tumor stages. In addition, HCC cell line stably expressing Pak1 displayed increased cell motility rates and, conversely, knockdown of endogenous Pak1 expression by small interfering RNA reduced the migration rates of HCC cells. In an established metastatic HCC cell line, we found that Pak1 was overexpressed compared with its primary HCC cell line and this overexpression was associated with higher cell motility. Importantly, we found that c-Jun NH2-terminal kinase (JNK) was activated in HCC cell lines overexpressing Pak1. Inhibition of the JNK activity by chemical inhibitor significantly reduced the migration rates of HCC cells via attenuation of paxillin phosphorylation at Ser178. In conclusion, our results document that Pak1 is overexpressed in HCCs and plays an important role in the metastasis of HCC. The mechanism by which Pak1 induces cancer metastasis may involve activation of JNK and phosphorylation of paxillin. [Cancer Res 2007;67(8):3601–8]
Tumor Necrosis Factor Receptor 1/c-Jun-NH2-Kinase Signaling Promotes Human Neoplasia
Authors: Zhang Jennifer Y. , Adams Amy E. , Ridky Todd W. , Tao Shiying , Khavari Paul A.
Published: April 2007

The tumor necrosis factor α receptor (TNFR1) activates downstream effectors that include the mitogen-activated protein kinase kinase 7 (MKK7)/c-Jun-NH2-kinase (JNK)/activator protein 1 (AP1) cascade. Here, we report that JNK is activated in a majority of spontaneous human squamous cell carcinomas (SCC). JNK pathway induction bypassed cell cycle restraints induced by oncogenic Ras and cooperated with Ras to convert normal human epidermis into tumors indistinguishable from SCC, confirming its oncogenic potency in human tissue. Inhibiting MKK7, JNK, and AP1 as well as TNFR1 itself using genetic, pharmacologic, or antibody-mediated approaches abolished invasive human epidermal neoplasia in a tumor cell autonomous fashion. The TNFR1/MKK7/JNK/AP1 cascade thus promotes human neoplasia and represents a potential therapeutic target for human epithelial cancers. [Cancer Res 2007;67(8):3827–34]
SAG/ROC2/Rbx2 Is a Novel Activator Protein-1 Target that Promotes c-Jun Degradation and Inhibits 12-O-Tetradecanoylphorbol-13-Acetate–Induced Neoplastic Transformation
Authors: Gu Qingyang , Tan Mingjia , Sun Yi
Published: April 2007

SAG (sensitive to apoptosis gene) was first identified as a stress-responsive protein that, when overexpressed, inhibited apoptosis both in vitro and in vivo. SAG was later found to be the second family member of ROC1 or Rbx1, a RING component of SCF and DCX E3 ubiquitin ligases. We report here that SAG/ROC2/Rbx2 is a novel transcriptional target of activator protein-1 (AP-1). AP-1 bound both in vitro and in vivo to two consensus binding sites in a 1.3-kb region of the mouse SAG promoter. The SAG promoter activity, as measured by luciferase reporter assay, was dependent on these sites. Consistently, endogenous SAG is induced by 12-O-tetradecanoylphorbol-13-acetate (TPA) with an induction time course following the c-Jun induction in both mouse epidermal JB6-Cl.41 and human 293 cells. TPA-mediated SAG induction was significantly reduced in JB6-Cl.41 cells overexpressing a dominant-negative c-Jun, indicating a requirement of c-Jun/AP-1. On the other hand, SAG seemed to modulate the c-Jun levels. When overexpressed, SAG remarkably reduced both basal and TPA-induced c-Jun levels, whereas SAG small interfering RNA (siRNA) silencing increased substantially the levels of both basal and TPA-induced c-Jun. Consistently, SAG siRNA silencing reduced c-Jun polyubiquitination and blocked c-Jun degradation induced by Fbw7, an F-box protein of SCF E3 ubiquitin ligase. Finally, SAG overexpression inhibited, whereas SAG siRNA silencing enhanced, respectively, the TPA-induced neoplastic transformation in JB6-Cl.41 preneoplastic model. Thus, AP-1/SAG establishes an autofeedback loop, in which on induction by AP-1, SAG promotes c-Jun ubiquitination and degradation, thus inhibiting tumor-promoting activity of AP-1. [Cancer Res 2007;67(8):3616–10]
Mechanistic Influences for Mutation Induction Curves after Exposure to DNA-Reactive Carcinogens
Authors: Doak Shareen H. , Jenkins Gareth J.S. , Johnson George E. , Quick Emma , Parry Elizabeth M. , Parry James M.
Published: April 2007

A mechanistic understanding of carcinogenic genotoxicity is necessary to determine consequences of chemical exposure on human populations and improve health risk assessments. Currently, linear dose-responses are assumed for DNA reactive compounds, ignoring cytoprotective processes that may limit permanent damage. To investigate the biological significance of low-dose exposures, human lymphoblastoid cells were treated with alkylating agents that have different mechanisms of action and DNA targets: methylmethane sulfonate (MMS), methylnitrosourea (MNU), ethylmethane sulfonate (EMS), and ethylnitrosourea (ENU). Chromosomal damage and point mutations were quantified with the micronucleus and hypoxanthine phosphoribosyltransferase forward mutation assays. MNU and ENU showed linear dose-responses, whereas MMS and EMS had nonlinear curves containing a range of nonmutagenic low doses. The lowest observed effect level for induction of chromosomal aberrations was 0.85 μg/mL MMS and 1.40 μg/mL EMS; point mutations required 1.25 μg/mL MMS and 1.40 μg/mL EMS before a mutagenic effect was detected. This nonlinearity could be due to homeostatic maintenance by DNA repair, which is efficient at low doses of compounds that primarily alkylate N7-G and rarely attack O atoms. A pragmatic threshold for carcinogenicity may therefore exist for such genotoxins. [Cancer Res 2007;67(8):3904–11]
Molecular Mechanisms Underlying FIP1L1-PDGFRA–Mediated Myeloproliferation
Authors: Buitenhuis Miranda , Verhagen Liesbeth P. , Cools Jan , Coffer Paul J.
Published: April 2007

An interstitial deletion on chromosome 4q12 resulting in the formation of the FIP1L1-PDGFRA fusion protein is involved in the pathogenesis of imatinib-sensitive chronic eosinophilic leukemia. The molecular mechanisms underlying the development of disease are largely undefined. Human CD34+ hematopoietic progenitor cells were used to investigate the role of FIP1L1-PDGFRA in modulating lineage development. FIP1L1-PDGFRA induced both proliferation and differentiation of eosinophils, neutrophils, and erythrocytes in the absence of cytokines, which could be inhibited by imatinib. Whereas expression of FIP1L1-PDGFRA in hematopoietic stem cells and common myeloid progenitors induced the formation of multiple myeloid lineages, expression in granulocyte-macrophage progenitors induced only the development of eosinophils, neutrophils, and myeloblasts. Deletion of amino acids 30 to 233 in the FIP1L1 gene [FIP1L1(1–29)-PDGFRA] gave rise to an intermediate phenotype, exhibiting a dramatic reduction in the number of erythrocytes. FIP1L1-PDGFRA and FIP1L1(1–29)-PDGFRA both induced the activation of p38 and extracellular signal-regulated kinase 1/2 (ERK1/2) in myeloid progenitors, whereas signal transducers and activators of transcription 5 (STAT5) and protein kinase B/c-akt were only activated by FIP1L1-PDGFRA. Dominant-negative STAT5 partially inhibited FIP1L1-PDGFRA–induced colony formation, whereas combined inhibition of phosphatidylinositol-3-kinase and ERK1/2 significantly reversed FIP1L1-PDGFRA–induced colony formation. Taken together, these results suggest that expression of FIP1L1-PDFGRA in human hematopoietic progenitors induce a myeloproliferative phenotype via activation of multiple signaling molecules including phosphatidylinositol-3-kinase, ERK1/2, and STAT5. [Cancer Res 2007;67(8):3759–66]
Malignant Glioma Cells Counteract Antitumor Immune Responses through Expression of Lectin-Like Transcript-1
Authors: Roth Patrick , Mittelbronn Michel , Wick Wolfgang , Meyermann Richard , Tatagiba Marcos , Weller Michael
Published: April 2007

Glioblastoma, one of the most lethal tumors, is paradigmatic for tumor-associated immunosuppression. Lectin-like transcript-1 (LLT1) is a newly identified ligand for the inhibitory natural killer (NK) cell receptor CD161. Here, we report that glioma cells express LLT1 mRNA and protein in vitro and in vivo, whereas expression levels in normal brain are low. LLT1 expression in human gliomas increases with the WHO grade of malignancy. We further show that transforming growth factor-β (TGF-β) up-regulates the expression of LLT1 in glioma cells. Small interfering RNA (siRNA)–mediated down-regulation of LLT1 in LNT-229 and LN-428 cells promotes their lysis by NK cells. Thus, LLT1 acts as a mediator of immune escape and contributes to the immunosuppressive properties of glioma cells. [Cancer Res 2007;67(8):3540–4]
Direct Intramyocardial But Not Intracoronary Injection of Bone Marrow Cells Induces Ventricular Arrhythmias in a Rat Chronic Ischemic Heart Failure Model
Authors: Fukushima Satsuki , Varela-Carver Anabel , Coppen Steven R. , Yamahara Kenichi , Felkin Leanne E. , Lee Joon , Barton Paul J.R. , Terracciano Cesare M.N. , Yacoub Magdi H. , Suzuki Ken
Published: April 2007

Background—

Therapeutic efficacy of bone marrow (BM) cell injection for treating ischemic chronic heart failure has not been established. In addition, experimental data are lacking on arrhythmia occurrence after BM cell injection. We hypothesized that therapeutic efficacy and arrhythmia occurrence induced by BM cell injection may be affected by the cell delivery route.

Methods and Results—

Three weeks after left coronary artery ligation, wild-type female rats were injected with 1×10
7
mononuclear BM cells derived from green fluorescent protein–transgenic male rats through either a direct intramyocardial or a retrograde intracoronary route. Both intramyocardial and intracoronary injection of BM cells demonstrated similar improvement in left ventricular ejection fraction measured by echocardiography and a similar graft size analyzed by real-time polymerase chain reaction for the Y chromosome–specific
Sry
gene. Noticeably, intramyocardial injection of BM cells induced frequent ventricular premature contractions (108±73 per hour at 7 days after BM cell injection), including multiform, consecutive ventricular premature contractions and ventricular tachycardia for the initial 14 days; intracoronary injection of BM cells and intramyocardial injection of phosphate-buffered saline rarely induced arrhythmias. Immunohistochemistry demonstrated that intramyocardial BM cell injection formed distinct cell clusters containing donor-derived cells and accumulated host-derived inflammatory cells in the infarct border zone, whereas intracoronary BM cell injection provided more homogeneous donor cell dissemination with less inflammation and without disrupting the native myocardial structure.

Conclusions—

BM cell injection is able to improve cardiac function in ischemic chronic heart failure but has a risk of arrhythmia occurrence when the intramyocardial route is used. Such arrhythmias may be prevented by using the intracoronary route.
Poly(ADP-Ribose) Polymerase Inhibition Reduces Atherosclerotic Plaque Size and Promotes Factors of Plaque Stability in Apolipoprotein E–Deficient Mice
Authors: Oumouna-Benachour Karine , Hans Chetan P. , Suzuki Yasuhiro , Naura Amarjit , Datta Rahul , Belmadani Souad , Fallon Kenneth , Woods Cooper , Boulares A. Hamid
Published: April 2007

Background—

Poly(ADP-ribose) polymerase (PARP) was suggested to play a role in endothelial dysfunction that is associated with a number of cardiovascular diseases. We hypothesized that PARP may play an important role in atherogenesis and that its inhibition may attenuate atherosclerotic plaque development in an experimental model of atherosclerosis.

Methods and Results—

Using a mouse (apolipoprotein E [ApoE]
−/−
) model of high-fat diet–induced atherosclerosis, we demonstrate an association between cell death and oxidative stress–associated DNA damage and PARP activation within atherosclerotic plaques. PARP inhibition by thieno[2,3-c]isoquinolin-5-one reduced plaque number and size and altered structural composition of plaques in these animals without affecting sera lipid contents. These results were corroborated genetically with the use of ApoE
−/−
mice that are heterozygous for PARP-1. PARP inhibition promoted an increase in collagen content, potentially through an increase in tissue inhibitor of metalloproteinase-2, and transmigration of smooth muscle cells to intima of atherosclerotic plaques as well as a decrease in monocyte chemotactic protein-1 production, all of which are markers of plaque stability. In PARP-1
−/−
macrophages, monocyte chemotactic protein-1 expression was severely inhibited because of a defective nuclear factor-κB nuclear translocation in response to lipopolysaccharide. Furthermore, PARP-1 gene deletion not only conferred protection to foam cells against H
2
O
2
-induced death but also switched the mode of death from necrosis to apoptosis.

Conclusions—

Our results suggest that PARP inhibition interferes with plaque development and may promote plaque stability, possibly through a reduction in inflammatory factors and cellular changes related to plaque dynamics. PARP inhibition may prove beneficial for the treatment of atherosclerosis.
Pathological Correlates of Late Drug-Eluting Stent Thrombosis
Authors: Finn Aloke V. , Joner Michael , Nakazawa Gaku , Kolodgie Frank , Newell John , John Mike C. , Gold Herman K. , Virmani Renu
Published: April 2007

Background—

Late stent thrombosis (LST) after Cypher and Taxus drug-eluting stent placement has emerged as a major concern. Although the clinical predictors of LST have been reported, specific morphological and histological correlates of LST remain unknown.

Methods and Results—

From a registry totaling 81 human autopsies of drug-eluting stents, 46 (62 lesions) had a drug-eluting stent implanted >30 days. We identified 28 lesions with thrombus and compared those with 34 of similar duration without thrombosis using computer-guided morphometric and histological analyses. LST was defined as an acute thrombus within a coronary artery stent in place >30 days. Multiple logistic generalized estimating equations modeling demonstrated that endothelialization was the best predictor of thrombosis. The morphometric parameter that best correlated with endothelialization was the ratio of uncovered to total stent struts per section. A univariable logistic generalized estimating equations model of occurrence of thrombus in a stent section versus ratio of uncovered to total stent struts per section demonstrated a marked increase in risk for LST as the number of uncovered struts increased. The odds ratio for thrombus in a stent with a ratio of uncovered to total stent struts per section >30% is 9.0 (95% CI, 3.5 to 22).

Conclusions—

The most powerful histological predictor of stent thrombosis was endothelial coverage. The best morphometric predictor of LST was the ratio of uncovered to total stent struts. Heterogeneity of healing is a common finding in drug-eluting stents with evidence of LST and demonstrates the importance of incomplete healing of the stented segment in the pathophysiology of LST.
A
1
Adenosine Receptor Upregulation Accompanies Decreasing Myocardial Adenosine Levels in Mice With Left Ventricular Dysfunction
Authors: Funakoshi Hajime , Zacharia Lefteris C. , Tang Zhonghua , Zhang Jin , Lee Ling L. , Good Julie C. , Herrmann David E. , Higuchi Yoshihiro , Koch Walter J. , Jackson Edwin K. , Chan Tung O. , Feldman Arthur M.
Published: April 2007

Background—

It is well known that adenosine levels are increased during ischemia and protect the heart during ischemia/reperfusion. However, less is known about the role of adenosine–adenosine receptor (AR) pathways in hearts with left ventricular dilation and dysfunction. Therefore, we assessed adenosine levels and selective AR expression in transgenic mice with left ventricular systolic dysfunction secondary to overexpression of tumor necrosis factor-α (TNF 1.6).

Methods and Results—

Cardiac adenosine levels were reduced by 70% at 3 and 6 weeks of age in TNF 1.6 mice. This change was accompanied by a 4-fold increase in the levels of A
1
-AR and a 50% reduction in the levels of A
2A
-AR. That the increase in A
1
-AR density was of physiological significance was shown by the fact that chronotropic responsiveness to the A
1
-AR selective agonist 2-chloro-
N
6
-cyclopentanyladenosine was enhanced in the TNF 1.6 mice. Similar changes in adenosine levels were found in 2 other models of heart failure, mice overexpressing calsequestrin and mice after chronic pressure overload, suggesting that the changes in adenosine-AR signaling were secondary to myocardial dysfunction rather than to TNF overexpression.

Conclusions—

Cardiac dysfunction secondary to the overexpression of TNF is associated with marked alterations in myocardial levels of adenosine and ARs. Modulation of the myocardial adenosine system and its signaling pathways may be a novel therapeutic target in patients with heart failure.
Norepinephrine, via β-Adrenoceptors, Regulates Bumetanide-Sensitive Cotransporter Type 1 Expression in Thick Ascending Limb Cells
Authors: Sonalker Prajakta A. , Jackson Edwin K.
Published: April 2007

The sympathetic nervous system, via norepinephrine, regulates renal sodium transport, and chronic sympathetic activation causes sustained increases in blood pressure by reducing sodium excretion. Our previous studies show that chronic norepinephrine infusion increases the abundance of the bumetanide-sensitive cotransporter type 1, the apical sodium transporter of the thick ascending limb of Henle’s loop. The present study was initiated to elucidate the mechanisms by which norepinephrine regulates the protein levels of this transporter in an immortalized thick ascending limb epithelial cell line. Treatment with norepinephrine, either alone or in the presence of actinomycin D or cycloheximide, had no effect on cotransporter mRNA levels. Treatment with norepinephrine, however, increased bumetanide-sensitive cotransporter type 1 protein levels (70% increase versus control;
P
=0.012), and pretreatment with cycloheximide blocked the effect of norepinephrine on bumetanide-sensitive cotransporter type 1 protein levels. To further elucidate the mechanism, thick ascending limb cells were treated with norepinephrine in the presence of phentolamine (α-adrenoceptor blocker), propranolol (β-adrenoceptor blocker), SQ22536 (adenylyl cyclase inhibitor), PD098059 (mitogen-activated protein kinase pathway inhibitor), H-89 (protein kinase A inhibitor), or staurosporine (protein kinase C inhibitor). Treatment with propranolol, SQ22536, and H-89 abolished the effects of norepinephrine on bumetanide-sensitive cotransporter type 1 protein levels, whereas staurosporine had no effect. Treatment with PD098059 partially inhibited the effects of norepinephrine (40% decrease versus norepinephrine;
P
=0.03), and treatment with phentolamine potentiated the effects of norepinephrine (30% increase versus norepinephrine;
P
=0.02) on bumetanide-sensitive cotransporter type 1 protein levels. We conclude that regulation of bumetanide-sensitive cotransporter type 1 by norepinephrine proceeds via the β-adrenoceptor receptor–cAMP–protein kinase A pathway that involves in part mitogen-activated protein kinases and that α-adrenoceptor activation negatively regulates bumetanide-sensitive cotransporter type 1 protein levels.
Whither Chinese Law?
Authors: Huang Philip C. C.
Published: April 2007

Current Chinese debates about “modernity” focus on what Chinese law was and is, and where it should go from here; this article argues that the answer should be sought in historical processes involved in the pursuit of modern ideals—such as scientific knowledge, industrial development, and citizen rights—and not in any one theory or ideology. The essay attempts to excavate from the past century's history of Chinese legal practice components of what might be considered Chinese modernity, with examples from such major areas of civil law as inheritance-old age support, property rights, torts, and divorce. In addition, it emphasizes the court mediation system created by the Chinese Communist Party and the “practical moralism” mode of thinking evident in both imperial and modern Chinese lawmaking, pointing out the many commonalities they share with the current “alternative dispute resolution” movement of the West and with the legal pragmatism tradition of modern American law. The proper direction of development of Chinese law lies neither simply in importing the formalist rights laws of the West nor simply in relying on the practical moralism of China's past but rather, and properly so, in their long-term coexistence, competition, division of labor, and mutual influence.
The Rule of Law without Due Process
Authors: Xiaoqun Xu
Published: April 2007

This article investigates one important aspect of the Chinese legal-judicial reform that was unfolding in the early twentieth century (1901-37): i.e., why and how certain types of violent crimes were categorized and punished outside the criminal code and the criminal procedural law that were adopted as the law of the land and applied in court. It will reveal a continuous tension between, on the one hand, the principles of the rule of law, judicial independence, and due process that guided the legal-judicial reform and were insisted on by judicial officials and, on the other hand, the desire of provincial and county administrative officials to resort to “quick justice” to punish and deter violent crimes. An analysis of that tension will help to illuminate not only criminal law and criminal justice but also an important dimension of provincial and county administrative and judicial practices in early-twentieth-century China.
The Determinants of Employee-Involvement Schemes: Private Sector Australian Evidence
Authors: Brown Michelle , Geddes Lori A. , Heywood John S.
Published: April 2007

Using data from the 1995 wave of the Australian Workplace Industrial Relations Survey, this article estimates the determinants of four types of group employee-involvement (EI) schemes: autonomous groups, quality circles, joint consultative committees and task forces.

The results indicate that EI is associated with employees having longer expected tenure and higher labour force attachment. The authors argue that this is sensible as EI will be more successful in settings of interdependent production, settings in which such employees are at a premium. The results also show that complementary HRM practices, such as formal training and incentive pay, are associated with an increased likelihood of EI. Unionization, size of workplace and the extent of competition are also confirmed as determinants.
Errorless Compliance Training
Authors: Ducharme Joseph M. , Sanjuan Elena , Drain Tammy
Published: April 2007

Errorless compliance training is a noncoercive, success-focused approach to treatment of problem behavior in children. The intervention involves graduated exposure of a child to increasingly more challenging requests at a slow enough rate to ensure that noncompliance rarely occurs, providing parents with many opportunities to reinforce cooperative responses and rendering punishment unnecessary. The authors evaluated this approach with three boys with characteristics of Asperger syndrome. Mothers first delivered a range of requests to their children and recorded child responses. For each child, the authors calculated compliance probability for all requests and categorized them into four probability levels, from those yielding high compliance (Level 1) to those that commonly led to opposition (Level 4). Treatment began with delivery of Level 1 requests. Requests from Levels 2 through 4 were faded in sequentially over several weeks. All three children demonstrated substantial generalized improvement in compliance.