bluuebunny/crossref_metadata_2025 huggingface dataset:
Real-time Imaging of Lymphogenic Metastasis in Orthotopic Human Breast Cancer
Authors: Dadiani Maya , Kalchenko Vyacheslav , Yosepovich Ady , Margalit Raanan , Hassid Yaron , Degani Hadassa , Seger Dalia
Published: August 2006

Metastatic spread to regional lymph nodes is one of the earliest events of tumor cell dissemination and presents a most significant prognostic factor for predicting survival of cancer patients. Real-time in vivo imaging of the spread of tumor cells through the lymphatic system can enhance our understanding of the metastatic process. Herein, we describe the use of in vivo fluorescence microscopy imaging to monitor the progression of lymph node metastasis as well as the course of spontaneous metastasis through the lymphatic system of orthotopic MDA-MB-231 human breast cancer tumors in severe combined immunodeficient mice. High-resolution noninvasive visualization of metastasizing cancer cells in the inguinal lymph nodes was achieved using cells expressing high levels of red fluorescent protein. Sequential imaging of these lymph nodes revealed the initial invasion of the tumor cells through the lymphatic system into the subcapsular sinuses followed by intrusion into the parenchyma of the nodes. FITC-dextran injected i.d. in the tumor area enabled simultaneous tracking of lymphatic vessels, labeled in green, and disseminated red cancer cells within these vessels. Fast snapshots of spontaneously metastasizing cells in the lymphatic vessels monitored the movement of a few tumor cells and the development of clumps clustered at lymphatic vessel junctions. Quantification of high interstitial fluid pressure (IFP) in the tumors and fast drainage rates of the FITC-dextran into the peritumoral lymphatic vessels suggested an IFP-induced intravasation into the lymphatic system. This work presents unprecedented live fluorescence images that may help to clarify the steps occurring in the course of spontaneous lymphogenic metastasis. (Cancer Res 2006; 66(16): 8037-41)
Influence of the Microenvironment on Melanoma Cell Fate Determination and Phenotype
Authors: Postovit Lynne-Marie , Seftor Elisabeth A. , Seftor Richard E.B. , Hendrix Mary J.C.
Published: August 2006

Tumor cells communicate bidirectionally with the surrounding microenvironment, sending and receiving topographical and molecular cues that direct diverse cellular phenomena, including differentiation, growth, and invasion. The microenvironment has long been acknowledged as a facilitator of melanoma progression, and recent studies have illuminated tumor-associated factors, including hypoxia and the extracellular matrix, as important mediators of melanocyte transformation and transdifferentiation. Although these findings portray the microenvironment as a perilous obstacle to the successful treatment of advanced melanomas, it is important to note that certain molecular milieus may be capitalized on as potential treatment modalities. Indeed, our group and others have elucidated the unique ability of embryonic microenvironments to normalize aggressive melanoma cells toward a more benign melanocytic phenotype. The microenvironment therefore presents a novel target for the treatment and ultimately the prevention of melanoma progression and metastasis. (Cancer Res 2006; 66(16): 7833-6)
Taxotere-Induced Inhibition of Human Endothelial Cell Migration Is a Result of Heat Shock Protein 90 Degradation
Authors: Murtagh Janice , Lu Haiyan , Schwartz Edward L.
Published: August 2006

In addition to effects on tumor cell proliferation and apoptosis, microtubule-binding agents are potent inhibitors of angiogenesis. The cancer chemotherapeutic drug Taxotere (docetaxel) inhibited vascular endothelial growth factor (VEGF)–induced human umbilical vein endothelial cell (HUVEC) migration in vitro at concentrations substantially lower than required to cause cell cycle arrest or apoptosis. Here, we show that Taxotere caused the ubiquitination and subsequent proteasomal degradation of heat shock protein 90 (Hsp90) in HUVEC. This prevented signaling from the focal adhesions and VEGF receptors and inhibited integrin activation. Taxotere prevented the VEGF-induced phosphorylation of focal adhesion kinase, Akt, and endothelial nitric oxide synthase (eNOS), all of which are Hsp90 client proteins. Taxotere completely blocked the VEGF-induced increase in eNOS activity, and the addition of a NO donor reversed the inhibitory effect of Taxotere on VEGF-induced migration. A similar reversal occurred with a proteasomal inhibitor of Hsp90 degradation. Furthermore, overexpression of Hsp90 rescued HUVEC from the inhibition of VEGF-induced migration by Taxotere. Previous studies have suggested that tubulin is also a client protein of Hsp90, and immunocytochemical analysis showed that Taxotere caused the dissociation of Hsp90 from tubulin. We suggest that uncomplexed Hsp90 is more susceptible to ubiquitination and subsequent proteasomal degradation than the bound form. Although inhibitors of Hsp90 are currently under clinical investigation as antitumor agents, this seems to be the first account of a drug that reduces Hsp90 function by enhancing its proteasomal degradation. Further, the loss of Hsp90 and the inactivation of Hsp90 client proteins are previously undescribed actions of Taxotere that may contribute to its antiangiogenic activity. (Cancer Res 2006; 66(16): 8192-9)
Stem Cell–like Glioma Cells Promote Tumor Angiogenesis through Vascular Endothelial Growth Factor
Authors: Bao Shideng , Wu Qiulian , Sathornsumetee Sith , Hao Yueling , Li Zhizhong , Hjelmeland Anita B. , Shi Qing , McLendon Roger E. , Bigner Darell D. , Rich Jeremy N.
Published: August 2006

Malignant gliomas are highly lethal cancers dependent on angiogenesis. Critical tumor subpopulations within gliomas share characteristics with neural stem cells. We examined the potential of stem cell–like glioma cells (SCLGC) to support tumor angiogenesis. SCLGC isolated from human glioblastoma biopsy specimens and xenografts potently generated tumors when implanted into the brains of immunocompromised mice, whereas non-SCLGC tumor cells isolated from only a few tumors formed secondary tumors when xenotransplanted. Tumors derived from SCLGC were morphologically distinguishable from non-SCLGC tumor populations by widespread tumor angiogenesis, necrosis, and hemorrhage. To determine a potential molecular mechanism for SCLGC in angiogenesis, we measured the expression of a panel of angiogenic factors secreted by SCLGC. In comparison with matched non-SCLGC populations, SCLGC consistently secreted markedly elevated levels of vascular endothelial growth factor (VEGF), which were further induced by hypoxia. In an in vitro model of angiogenesis, SCLGC-conditioned medium significantly increased endothelial cell migration and tube formation compared with non-SCLGC tumor cell–conditioned medium. The proangiogenic effects of glioma SCLGC on endothelial cells were specifically abolished by the anti-VEGF neutralizing antibody bevacizumab, which is in clinical use for cancer therapy. Furthermore, bevacizumab displayed potent antiangiogenic efficacy in vivo and suppressed growth of xenografts derived from SCLGC but limited efficacy against xenografts derived from a matched non-SCLGC population. Together these data indicate that stem cell–like tumor cells can be a crucial source of key angiogenic factors in cancers and that targeting proangiogenic factors from stem cell–like tumor populations may be critical for patient therapy. (Cancer Res 2006; 66(16): 7843-8)
Wilms' Tumor 1 and Signal Transducers and Activators of Transcription 3 Synergistically Promote Cell Proliferation: A Possible Mechanism in Sporadic Wilms' Tumor
Authors: Rong Yu , Cheng Long , Ning Hongxiu , Zou Jizhen , Zhang Yuanjiang , Xu Fang , Liu Li , Chang Zhijie , Fu Xin-Yuan
Published: August 2006

Transcription factor Wilms' tumor 1 (WT1) was originally identified as a tumor suppressor for Wilms' tumor, but it is also overexpressed in a variety of cancer cells, suggesting a potential oncogenic function of WT1. It is important to understand molecular mechanisms underlying these dual functions of WT1 in tumorigenesis. In the current study, we report a synergistic role for signal transducers and activators of transcription 3 (STAT3) and WT1 in tumor development, including Wilms' tumor. STAT3 interacts with WT1 through its conserved domains both in vitro and in vivo. When STAT3 is activated, expression of WT1 enhances STAT3 transcriptional activity. Overexpression of WT1 and STAT3CA in NIH 3T3 increases the expression level of STAT3 target genes, including cyclin D1 and Bcl-xL, which results in an advantage of cell proliferation. Our results suggest that in the presence of activated STAT3, WT1 promotes cell proliferation instead of suppressing cell proliferation. Strikingly, STAT3 translocates to the nucleus and interacts with WT1 in a variety of primary Wilms' tumor cells, raising the hypothesis that WT1 and activated STAT3 in Wilms' tumor accelerate tumorigenesis. (Cancer Res 2006; 66(16): 8049-57)
The Anti-CD25 Monoclonal Antibody 7G7/B6, Armed with the α-Emitter 211At, Provides Effective Radioimmunotherapy for a Murine Model of Leukemia
Authors: Zhang Meili , Yao Zhengsheng , Zhang Zhuo , Garmestani Kayhan , Talanov Vladimir S. , Plascjak Paul S. , Yu Sarah , Kim Hyung-Sik , Goldman Carolyn K. , Paik Chang H. , Brechbiel Martin W. , Carrasquillo Jorge A. , Waldmann Thomas A.
Published: August 2006

Radioimmunotherapy of cancer with radiolabeled antibodies has shown promise. α-Particles are very attractive for cancer therapy, especially for isolated malignant cells, as is observed in leukemia, because of their high linear energy transfer and short effective path length. We evaluated an anti-CD25 [interleukin-2 receptor α (IL-2Rα)] monoclonal antibody, 7G7/B6, armed with 211At as a potential radioimmunotherapeutic agent for CD25-expressing leukemias and lymphomas. Therapeutic studies were done in severe combined immunodeficient/nonobese diabetic mice bearing the karpas299 leukemia and in nude mice bearing the SUDHL-1 lymphoma. The results from a pharmacokinetic study showed that the clearance of 211At-7G7/B6 from the circulation was virtually identical to 125I-7G7/B6. The biodistributions of 211At-7G7/B6 and 125I-7G7/B6 were also similar with the exception of a higher stomach uptake of radioactivity with 211At-7G7/B6. Therapy using 15 μCi of 211At-7G7/B6 prolonged survival of the karpas299 leukemia–bearing mice significantly when compared with untreated mice and mice treated with 211At-11F11, a radiolabeled nonspecific control antibody (P < 0.01). All of the mice in the control and 211At-11F11 groups died by day 46 whereas >70% of the mice in the 211At-7G7/B6 group still survived at that time. In summary, 211At-7G7/B6 could serve as an effective therapeutic agent for patients with CD25-expressing leukemias. (Cancer Res 2006; 66(16): 8227-32)
Gene Expression Profiles Identify Epithelial-to-Mesenchymal Transition and Activation of Nuclear Factor-κB Signaling as Characteristics of a High-risk Head and Neck Squamous Cell Carcinoma
Authors: Chung Christine H. , Parker Joel S. , Ely Kim , Carter Jesse , Yi Yajun , Murphy Barbara A. , Ang K. Kian , El-Naggar Adel K. , Zanation Adam M. , Cmelak Anthony J. , Levy Shawn , Slebos Robbert J. , Yarbrough Wendell G.
Published: August 2006

Gene expression signatures generated from DNA microarray analyses have shown promise as predictive biomarkers of clinical outcome. In this study, we determined a high-risk signature for disease recurrence using formalin-fixed head and neck squamous cell carcinoma (HNSCC) tumors and compared the results with an independent data set obtained from fresh frozen tumors. We also showed that genes involved in epithelial-to-mesenchymal transition (EMT) and nuclear factor-κB (NF-κB) signaling deregulation are the most prominent molecular characteristics of the high-risk tumors. Gene expression was determined in 40 samples, including 34 formalin-fixed tissues and 6 matched frozen tissues, from 29 HNSCC patients. A 75-gene list predictive of disease recurrence was determined by training on the formalin-fixed tumor data set and tested on data from the independent frozen tumor set from 60 HNSCC patients. The difference in recurrence-free survival (RFS) between the high-risk versus low-risk groups in the training and test sets was statistically significant (P = 0.002 and 0.03, respectively, log-rank test). In addition, the gene expression data was interrogated using Gene Set Enrichment Analysis to determine biological significance. The most significant sets of genes enriched in the high-risk tumors were genes involving EMT, NF-κB activation, and cell adhesion. In conclusion, global gene expression analysis is feasible using formalin-fixed tissue. The 75-gene list can be used as a prognostic biomarker of recurrence, and our data suggest that the molecular determinants of EMT and NF-κB activation can be targeted as the novel therapy in the identified high-risk patients. (Cancer Res 2006; 66(16): 8210-8)
Discoidin Domain Receptor 1 Receptor Tyrosine Kinase Induces Cyclooxygenase-2 and Promotes Chemoresistance through Nuclear Factor-κB Pathway Activation
Authors: Das Sanjeev , Ongusaha Pat P. , Yang Yoon Sun , Park Jin-Mo , Aaronson Stuart A. , Lee Sam W.
Published: August 2006

Discoidin domain receptor 1 (DDR1) is a receptor tyrosine kinase activated by various types of collagens and is known to play a role in cell attachment, migration, survival, and proliferation. However, little is known about the molecular mechanism(s) underlying the role of DDR1 in cancer. We report here that DDR1 induces cyclooxygenase-2 (Cox-2) expression resulting in enhanced chemoresistance. Depletion of DDR1-mediated Cox-2 induction using short hairpin RNA (shRNA) results in increased chemosensitivity. We also show that DDR1 activates the nuclear factor-κB (NF-κB) pathway and blocking this activation by an IκB superrepressor mutant results in the ablation of DDR1-induced Cox-2, leading to enhanced chemosensitivity, indicating that DDR1-mediated Cox-2 induction is NF-κB dependent. We identify the upstream activating kinases of the NF-κB pathway, IKKβ and IKKγ, as essential for DDR1-mediated NF-κB activation, whereas IKKα seems to be dispensable. Finally, shRNA-mediated inhibition of DDR1 expression significantly enhanced chemosensitivity to genotoxic drugs in breast cancer cells. Thus, DDR1 signaling provides a novel target for therapeutic intervention with the prosurvival/antiapoptotic machinery of tumor cells. (Cancer Res 2006; 66(16): 8123-30)
Role of Nongenomic Activation of Phosphatidylinositol 3-Kinase/Akt and Mitogen-Activated Protein Kinase/Extracellular Signal-Regulated Kinase Kinase/Extracellular Signal-Regulated Kinase 1/2 Pathways in 1,25D3-Mediated Apoptosis in Squamous Cell Carcinoma Cells
Authors: Ma Yingyu , Yu Wei-Dong , Kong Rui-Xian , Trump Donald L. , Johnson Candace S.
Published: August 2006

Vitamin D is a steroid hormone that regulates calcium homeostasis and bone metabolism. The active form of vitamin D [1α,25-dihydroxyvitamin D3 (1,25D3)] acts through both genomic and nongenomic pathways. 1,25D3 has antitumor effects in a variety of cancers, including colorectal, prostate, breast, ovarian, and skin cancers. 1,25D3 exerts growth-inhibitory effects in cancer cells through the induction of apoptosis, cell cycle arrest, and differentiation. The mechanisms regulating 1,25D3-induced apoptosis remain unclear. We investigated the role of nongenomic signaling in 1,25D3-mediated apoptosis in squamous cell carcinoma (SCC) cells. 1,25D3 induced rapid and sustained activation of phosphatidylinositol 3-kinase/Akt and mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK) 1/2 pathways in SCC cells. These effects were nongenomic: they occurred rapidly and were not inhibited by cycloheximide or actinomycin D. To examine whether the nongenomic activation of Akt and ERK1/2 plays a role in 1,25D3-mediated apoptosis, the expression of Akt or ERK1/2 was reduced by small interfering RNA (siRNA). siRNA-Akt significantly enhanced 1,25D3-induced apoptosis as indicated by increased levels of Annexin V–positive cells and increased sub-G1 population and DNA fragmentation. In contrast, siRNA-ERK1/2 had no effects on 1,25D3-induced apoptosis. In addition, siRNA-Akt transfection followed by 1,25D3 treatment induced apoptosis much sooner than 1,25D3 alone. siRNA-Akt and 1,25D3 induced caspase-10 activation, suppressed the expression of c-IAP1 and XIAP, and promoted 1,25D3-induced caspase-3 activation. These results support a link between 1,25D3-induced nongenomic signaling and apoptosis. 1,25D3 induces the activation of phosphatidylinositol 3-kinase/Akt, which suppresses 1,25D3-mediated apoptosis and prolongs the survival of SCC cells. (Cancer Res 2006; 66(16): 8131-8)
Spontaneous Fusion with, and Transformation of Mouse Stroma by, Malignant Human Breast Cancer Epithelium
Authors: Jacobsen Britta M. , Harrell J. Chuck , Jedlicka Paul , Borges Virginia F. , Varella-Garcia Marileila , Horwitz Kathryn B.
Published: August 2006

Adenocarcinoma cells from the pleural effusion of a patient with breast cancer were injected into the mammary glands of nude mice and grown into solid tumors. A cell line derived from these tumors expressed α-smooth muscle actin but not human cytokeratin 7, indicating “activated” stroma of mouse origin. Cells in mitosis exhibited mainly polyploid mouse karyotypes, but 30% had mixed mouse and human chromosomes, among which 8% carried mouse/human translocations. Nuclei of interphase cells were 64% hybrid. Hybrid mouse/human nuclei were also detected in the primary xenograft. Thus, synkaryons formed in the solid tumor by spontaneous fusion between the malignant human epithelium and the surrounding normal host mouse stroma. The transformed stroma-derived cells are tumorigenic with histopathologic features of malignancy, suggesting a new mechanism for tumor progression. (Cancer Res 2006; 66(16): 8274-9)
Emergence of Androgen Independence at Early Stages of Prostate Cancer Progression in Nkx3.1; Pten Mice
Authors: Gao Hui , Ouyang Xuesong , Banach-Petrosky Whitney A. , Shen Michael M. , Abate-Shen Cory
Published: August 2006

Although androgen deprivation therapy is a widely used treatment for patients with advanced prostate cancer, it ultimately results in the emergence of a hormone-refractory disease that is invariably fatal. To provide insights into the genesis of this disease, we have employed an in vivo model to investigate how and when prostate epithelial cells can acquire the ability to survive and proliferate in the absence of androgens. In particular, we have been studying the evolution of androgen independence in Nkx3.1; Pten mutant mice, which develop prostatic intraepithelial neoplasia and adenocarcinoma as a consequence of aging, as well as androgen-independent phenotypes following castration. We now find that the prostate epithelial cells from these Nkx3.1; Pten mutant mice are capable of surviving and proliferating in the absence of androgens and that they develop androgen-independent phenotypes well before they display overt prostatic intraepithelial neoplasia or cancer phenotypes. Our findings in this mouse model show that acquisition of androgen independence can be uncoupled from overt cancer progression and raise the possibility that hormone-refractory disease can arise at early stages of prostate carcinogenesis. (Cancer Res 2006; 66(16): 7929-33)
GRP78 as a Novel Predictor of Responsiveness to Chemotherapy in Breast Cancer
Authors: Lee Eunjung , Nichols Peter , Spicer Darcy , Groshen Susan , Yu Mimi C. , Lee Amy S.
Published: August 2006

The discovery of predictive factors for chemoresistance is critical for improving adjuvant therapy for cancer patients. The 78-kDa glucose-regulated protein (GRP78), widely used as an indicator of the unfolded protein response (UPR), is induced in the tumor microenvironment. In vitro studies suggest that GRP78 confers chemoresistance to topoisomerase inhibitors, such as Adriamycin (doxorubicin). Here, we report on a retrospective cohort study of 127 stage II and III breast cancer patients who were treated with Adriamycin-based chemotherapy. Archival tumor specimens were available for analysis and the relationship of GRP78 expression level to “time to recurrence” (TTR), used as a surrogate marker for drug resistance, was examined. Our data show that 67% of the study subjects expressed high level of GRP78 in their tumors before the initiation of chemotherapy and suggest an association between GRP78 positivity and shorter TTR [hazard ratio (HR), 1.78; P = 0.16]. Interestingly, subgroup analysis reveals that the HR for the GRP78-positive group increased significantly among patients who did not receive further taxane treatment (HR, 3.00; P = 0.022) and among mastectomy patients (HR, 3.33; P = 0.027). The HR was even stronger among mastectomy patients who did not receive further taxane treatment (HR, 4.82; P = 0.010). The use of GRP78 as a predictor for chemoresponsiveness and the potential interaction of GRP78 and/or the UPR pathways with taxanes warrant larger studies. (Cancer Res 2006; 66(16): 7849-53)
Tsc1Haploinsufficiency without Mammalian Target of Rapamycin Activation Is Sufficient for Renal Cyst Formation inTsc1+/− Mice
Authors: Wilson Catherine , Bonnet Cleo , Guy Carol , Idziaszczyk Shelley , Colley James , Humphreys Vikki , Maynard Julie , Sampson Julian R. , Cheadle Jeremy P.
Published: August 2006

Tuberous sclerosis complex (TSC) is caused by mutations in either the TSC1 or TSC2 gene. Both genes are generally considered to act as tumor suppressors that fulfill Knudson's “two-hit hypothesis” and that function within the phosphoinositide 3-kinase-Akt-mammalian target of rapamycin (mTOR) pathway. We previously generated Tsc1+/− mice that are predisposed to renal cysts, which develop into cystadenomas and renal cell carcinomas. Here, we identified somatic Tsc1 mutations (second hits) in ∼80% of cystadenomas and renal cell carcinomas, but only 31.6% of cysts from Tsc1+/− mice (P < 0.0003), raising the possibility that haploinsufficiency for Tsc1 plays a role in cyst formation. Consistent with this proposal, many cysts showed little or no staining for phosphorylated mTOR (53%) and phosphorylated S6 ribosomal protein (37%), whereas >90% of cystadenomas and renal cell carcinomas showed strong staining for both markers (P < 0.0005). We also sought somatic mutations in renal lesions from Tsc1+/− Blm−/− mice that have a high frequency of somatic loss of heterozygosity, thereby facilitating the detection of second hits. We also found significantly less somatic mutations in cysts as compared with cystadenomas and renal cell carcinomas from these mice (P = 0.017). Our data indicate that although activation of the mTOR pathway is an important step in Tsc-associated renal tumorigenesis, it may not be the key initiating event in this process. (Cancer Res 2006; 66(16): 7934-8)
MIRA-Assisted Microarray Analysis, a New Technology for the Determination of DNA Methylation Patterns, Identifies Frequent Methylation of Homeodomain-Containing Genes in Lung Cancer Cells
Authors: Rauch Tibor , Li Hongwei , Wu Xiwei , Pfeifer Gerd P.
Published: August 2006

We present a straightforward and comprehensive approach for DNA methylation analysis in mammalian genomes. The methylated-CpG island recovery assay (MIRA), which is based on the high affinity of the MBD2/MBD3L1 complex for methylated DNA, has been used to detect cell type–dependent differences in DNA methylation on a microarray platform. The procedure has been verified and applied to identify a series of novel candidate lung tumor suppressor genes and potential DNA methylation markers that contain methylated CpG islands. One gene of particular interest was DLEC1, located at a commonly deleted area on chromosome 3p22-p21.3, which was frequently methylated in primary lung cancers and melanomas. Among the identified methylated genes, homeodomain-containing genes were unusually frequent (11 of the top 50 hits) and were targeted on different chromosomes. These genes included LHX2, LHX4, PAX7, HOXB13, LBX1, SIX2, HOXD3, DLX1, HOXD1, ONECUT2, and PAX9. The data show that MIRA-assisted microarray analysis has a low false-positive rate and has the capacity to catalogue methylated CpG islands on a genome-wide basis. The results support the hypothesis that cancer-associated DNA methylation events do not occur randomly throughout the genome but at least some are targeted by specific mechanisms. (Cancer Res 2006; 66(16): 7939-47)
Enalapril Attenuates Downregulation of Angiotensin-Converting Enzyme 2 in the Late Phase of Ventricular Dysfunction in Myocardial Infarcted Rat
Authors: Ocaranza María Paz , Godoy Ivan , Jalil Jorge E. , Varas Manuel , Collantes Patricia , Pinto Melissa , Roman Maritza , Ramirez Cristián , Copaja Miguel , Diaz-Araya Guillermo , Castro Pablo , Lavandero Sergio
Published: August 2006

The early and long-term effects of coronary artery ligation on the plasma and left ventricular angiotensin-converting enzyme (ACE and ACE2) activities, ACE and ACE2 mRNA levels, circulating angiotensin (Ang) levels [Ang I, Ang-(1-7), Ang-(1-9), and Ang II], and cardiac function were evaluated 1 and 8 weeks after experimental myocardial infarction in adult Sprague Dawley rats. Sham-operated rats were used as controls. Coronary artery ligation caused myocardial infarction, hypertrophy, and dysfunction 8 weeks after surgery. At week 1, circulating Ang II and Ang-(1-9) levels as well as left ventricular and plasma ACE and ACE2 activities increased in myocardial-infarcted rats as compared with controls. At 8 weeks post-myocardial infarction, circulating ACE activity, ACE mRNA levels, and Ang II levels remained higher, but plasma and left ventricular ACE2 activities and mRNA levels and circulating levels of Ang-(1-9) were lower than in controls. No changes in plasma Ang-(1-7) levels were observed at any time. Enalapril prevented cardiac hypertrophy and dysfunction as well as the changes in left ventricular ACE, left ventricular and plasmatic ACE2, and circulating levels of Ang II and Ang-(1-9) after 8 weeks postinfarction. Thus, the decrease in ACE2 expression and activity and circulating Ang-(1-9) levels in late ventricular dysfunction post-myocardial infarction were prevented with enalapril. These findings suggest that in this second arm of the renin-angiotensin system, ACE2 may act through Ang-(1-9), rather than Ang-(1-7), as a counterregulator of the first arm, where ACE catalyzes the formation of Ang II.
Randomized, Double-Blind, Multicenter Study of the Endeavor Zotarolimus-Eluting Phosphorylcholine-Encapsulated Stent for Treatment of Native Coronary Artery Lesions
Authors: Fajadet Jean , Wijns William , Laarman Gert-Jan , Kuck Karl-Heinz , Ormiston John , Münzel Thomas , Popma Jeffrey J. , Fitzgerald Peter J. , Bonan Raoul , Kuntz Richard E.
Published: August 2006

Background—

The use of the Endeavor stent might reduce restenosis and stent thrombosis at 9 months.

Methods and Results—

Patients (n=1197) treated for single coronary artery stenosis were enrolled in a prospective, randomized, double-blind study and randomly assigned to receive the Endeavor zotarolimus-eluting phosphorylcholine polymer–coated stent (n=598) or the same bare metal stent but without the drug or the polymer coating (n=599). The 2 groups were well matched in baseline characteristics. Diabetes was present in 20.1% of patients; the mean reference vessel diameter was 2.75 mm; and the mean lesion length was 14.2 mm. The primary end point of target vessel failure at 9 months was reduced from 15.1% with the bare metal stent to 7.9% with the Endeavor (
P
=0.0001), and the rate of major adverse cardiac events was reduced from 14.4% with the bare metal stent to 7.3% with the Endeavor (
P
=0.0001). Target lesion revascularization was 4.6% with Endeavor compared with 11.8% with the bare metal stent (
P
=0.0001). The rate of stent thrombosis was 0.5% with the Endeavor, which was not significantly different from 1.2% with the bare metal stent. In 531 patients submitted to angiographic follow-up, late loss was reduced from 1.03±0.58 to 0.61±0.46 (
P
<0.001) in stent and from 0.72±0.61 to 0.36±0.46 (
P
<0.001) in segment. The rate of in-segment restenosis was reduced from 35.0% to 13.2% with Endeavor (
P
<0.0001). There was no excessive edge stenosis, aneurysm formation, or late acquired malapposition by intravascular ultrasound imaging. Differences in clinical outcome were maintained at 12 and 24 months (
P
<0.0001).

Conclusions—

Compared with bare metal stents, the Endeavor stent is safe and reduces the rates of clinical and angiographic restenosis at 9, 12, and 24 months.
Oxidized Lipid-Driven Chemokine Receptor Switch, CCR2 to CX3CR1, Mediates Adhesion of Human Macrophages to Coronary Artery Smooth Muscle Cells Through a Peroxisome Proliferator-Activated Receptor γ–Dependent Pathway
Authors: Barlic Jana , Zhang Yuan , Foley John F. , Murphy Philip M.
Published: August 2006

Background—

Recent genetic data in mouse and humans suggest that the chemokine receptors CCR2 and CX3CR1 are involved in atherogenesis; however, detailed molecular and cellular mechanisms have not been fully delineated.

Methods and Results—

Here, we show that oxidized linoleic acid metabolites, which are components of oxidized LDL found in large amounts in atherosclerotic plaque, were able to specifically induce differentiation of human monocytes to macrophages with decreased expression of CCR2, confirming a previous report, and increased expression of CX3CR1. These macrophages acquired the ability to adhere to coronary artery smooth muscle cells. The adhesion was mediated directly and predominantly by CX3CR1. Reciprocal effects of these lipids on CCR2 and CX3CR1 expression were mediated by the nuclear receptor peroxisome proliferator-activated receptor (PPAR) γ, and targeting the
PPARγ
gene with sRNAi dramatically reduced macrophage adhesion to coronary artery smooth muscle cells.

Conclusions—

These data suggest that in atherogenesis oxidized lipid-driven activation of macrophage PPARγ in the intima may result in a proadhesive chemokine receptor switch–CCR2 off, CX3CR1 on–causing cessation of CCR2-dependent migration and activation of CX3CR1-dependent retention mechanisms, which together promote macrophage accumulation in vessel wall. Our results may explain at the molecular and cell biology levels the genetic link between CX3CR1 and atherosclerosis. Moreover, they identify macrophage binding to coronary artery smooth muscle cells as the first primary cell setting in which CX3CR1 functions as the major adhesion system.
Adverse Impact of Bleeding on Prognosis in Patients With Acute Coronary Syndromes
Authors: Eikelboom John W. , Mehta Shamir R. , Anand Sonia S. , Xie Changchun , Fox Keith A.A. , Yusuf Salim
Published: August 2006

Background—

The use of multiple antithrombotic drugs and aggressive invasive strategies has increased the risk of major bleeding in acute coronary syndrome (ACS) patients. It is not known to what extent bleeding determines clinical outcome.

Methods and Results—

Using Cox proportional-hazards modeling, we examined the association between bleeding and death or ischemic events in 34 146 patients with ACS enrolled in the Organization to Assess Ischemic Syndromes and the Clopidogrel in Unstable Angina to Prevent Recurrent Events studies. Patients with major bleeding were older, more often had diabetes or a history of stroke, had a lower blood pressure and higher serum creatinine, more often had ST-segment changes on the presenting ECG, and had a 5-fold-higher incidence of death during the first 30 days (12.8% versus 2.5%;
P
<0.0001) and a 1.5-fold-higher incidence of death between 30 days and 6 months (4.6% versus 2.9%;
P
=0.002). Major bleeding was independently associated with an increased hazard of death during the first 30 days (hazard ratio, 5.37; 95% CI, 3.97 to 7.26;
P
<0.0001), but the hazard was much weaker after 30 days (hazard ratio, 1.54; 95% CI, 1.01 to 2.36;
P
=0.047). The association was consistent across subgroups according to cointerventions during hospitalization, and there was an increasing risk of death with increasing severity of bleeding (minor less than major less than life-threatening;
P
for trend=0.0009). A similar association was evident between major bleeding and ischemic events, including myocardial infarction and stroke.

Conclusions—

In ACS patients without persistent ST-segment elevation, there is a strong, consistent, temporal, and dose-related association between bleeding and death. These data should lead to greater awareness of the prognostic importance of bleeding in ACS and should prompt evaluation of strategies to reduce bleeding and thereby improve clinical outcomes.
Redefinition of Myocardial Infarction
Authors: Roger Véronique L. , Killian Jill M. , Weston Susan A. , Jaffe Allan S. , Kors Jan , Santrach Paula J. , Tunstall-Pedoe Hugh , Jacobsen Steven J.
Published: August 2006

Background—

The 2000 European Society of Cardiology/American College of Cardiology definition for myocardial infarction (MI) combines ischemic symptoms, electrocardiographic changes, and troponin rather than creatine kinase levels. The use of troponins will increase the detection of MI by a magnitude to be quantified, and the clinical acceptance of the new definition is unknown.

Method and Results—

Subjects presenting to an Olmsted County facility with a troponin T value ≥0.03 ng/mL between November 2002 and March 2005 were prospectively classified through the use of standardized MI criteria, relying on cardiac pain, Minnesota coding of the ECG, and troponin, creatine kinase, and its MB fraction measured simultaneously. Through the use of dynamic changes in troponin, 538 MIs were identified versus 327 with creatine kinase and 427 with only the MB fraction of creatine kinase. This represents a 74% (95% confidence interval [CI], 69% to 79%) increase above the number of MIs identified with creatine kinase and a 41% (95% CI, 37% to 46%) increase above the number identified with criteria including only its MB fraction. When relying on single values of troponin, increases in the number of MIs were always large but varied widely according to the threshold used for troponin. Cases meeting only troponin-based criteria were less likely to have electrocardiographic ST-segment elevation and had better survival than those identified with previous criteria. Clinician diagnoses mentioned MI in 42% (95% CI, 34% to 49%) of cases meeting only troponin-based criteria versus 74% (95% CI, 69% to 78%) for MIs meeting the previous criteria (
P
<0.001).

Conclusions—

The prospective application of the new criteria in the community results in a large increase in the number of MIs and a change in case mix. The clinical acceptance of the new criteria is incomplete, and studies that rely exclusively on dismissal diagnoses to assess MI rates may underestimate the burden of disease as presently defined.
α
2
(VIII) Collagen Substrata Enhance Endothelial Cell Retention Under Acute Shear Stress Flow via an α
2
β
1
Integrin–Dependent Mechanism
Authors: Turner Neill J. , Murphy Michael O. , Kielty Cay M. , Shuttleworth C. Adrian , Black Richard A. , Humphries Martin J. , Walker Michael G. , Canfield Ann E.
Published: August 2006

Background—

Essential to tissue-engineered vascular grafts is the formation of a functional endothelial monolayer capable of resisting the forces of blood flow. This study targeted α
2
(VIII) collagen, a major component of the subendothelial matrix, and examined the ability of and mechanisms by which endothelial cells attach to this collagen under static and dynamic conditions both in vitro and in vivo.

Methods and Results—

Attachment of human endothelial cells to recombinant α
2
(VIII) collagen was assessed in vitro under static and shear conditions of up to 100 dyne/cm
2
. α
2
(VIII) collagen supported endothelial cell attachment in a dose-dependent manner, with an 18-fold higher affinity for endothelial cells compared with fibronectin. Cell attachment was significantly inhibited by function-blocking anti-α
2
(56%) and -β
1
(98%) integrin antibodies but was not RGD dependent. Under flow, endothelial cells were retained at significantly higher levels on α
2
(VIII) collagen (53% and 51%) than either fibronectin (23% and 16%) or glass substrata (7% and 1%) at shear rates of 30 and 60 dyne/cm
2
, respectively. In vivo studies, using endothelialized polyurethane grafts, demonstrated significantly higher cell retention rates to α
2
(VIII) collagen-coated than to fibronectin-coated prostheses in the midgraft area (
P
<0.05) after 24 hours’ implantation in the caprine carotid artery.

Conclusions—

These studies demonstrate that α
2
(VIII) collagen has the potential to improve both initial cell attachment and retention of endothelial cells on vascular grafts in vivo, which opens new avenues of research into the development of single-stage endothelialized prostheses and the next generation of tissue-engineered vascular grafts.
Risk Stratification of Patients With Acute Anterior Myocardial Infarction and Right Bundle-Branch Block
Authors: Wong Cheuk-Kit , Gao Wanzhen , Stewart Ralph A.H. , van Pelt Niels , French John K. , Aylward Philip E.G. , White Harvey D.
Published: August 2006

Background—

Patients with an acute anterior ST-segment elevation myocardial infarction and right bundle-branch block (RBBB) have a high mortality risk, which may be stratified by early ECG changes.

Methods and Results—

In the Hirulog Early Reperfusion Occlusion (HERO-2) trial, 17 073 patients with acute myocardial infarction (AMI) within 6 hours of symptom onset were treated with streptokinase and randomized to receive bivalirudin or heparin. There was no difference in the primary end point of 30-day mortality. ECGs were recorded at randomization and 60 minutes after fibrinolytic therapy was begun. The 30-day mortality rate was 31.6% in the 415 patients with RBBB and anterior AMI at randomization and 33% in the 100 patients who developed new RBBB at 60 minutes from normal baseline conduction accompanying an anterior AMI. An increase in QRS duration by 20-ms increments was associated with increasing 30-day mortality rate in both RBBB groups on multivariable analyses with covariates of age, Killip class, systolic blood pressure, pulse, and prior infarction. Patients with QRS duration ≥160 ms had higher 30-day mortality rate than those with QRS duration <160 ms (37.2% versus 27.2%,
P
=0.03, and 46.2% versus 24.5%,
P
=0.025, in the 2 groups, respectively). For the patients with RBBB and anterior MI at randomization, RBBB resolved at 60 minutes in 40 patients, but 30-day mortality rate was unchanged. For those with persisting RBBB at 60 minutes, 30-day mortality rate was lower if ST-segment elevation had resolved by ≥50% (20.4% versus 35.3%,
P
=0.006).

Conclusions—

In patients with anterior AMI and RBBB, increasing QRS duration is associated with increasing 30-day mortality. Early ST-segment resolution after fibrinolytic therapy despite persisting RBBB is associated with lower mortality rate.
The Epistle of Barnabas
Authors: Paget James Carleton
Published: August 2006

We know little that is certain about the author, origins or provenance of the Epistle of Barnabas, although most assume it to be Egyptian and written in the first third of the first century CE. In large part the letter concerns itself with questions relating to the interpretation of scripture, in particular the Torah. Its author expresses some singular views (the Law of Moses should never have been interpreted in a literal way; the covenant was lost by the Jews as a result of their worship of the golden calf), and he has been seen by some as the first Christian writer ‘adversus Judaeos’.
Learning and Cooperation in Sequential Games
Authors: Valluri Annapurna
Published: August 2006

The predictions of classical game theory for one-shot and finitely repeated play of many 2x2 simulta neous games do not correspond to human behavior observed in laboratory experiments. The promis ing results of learning models in tracking human behavior coupled with the growing electronic market and the number of e-commerce applications has resulted in an increased interest in studying the behavior of adaptive artificial agents in different economic games. We model agents with a reinforce ment learning algorithm and analyze cooperative behavior in a sequential prisoner's dilemma game. Our results demonstrate the ability of artificial agents to learn cooperative behavior even in sequential games where defection is the subgame perfect Nash equilibrium. We attribute the reciprocal-like behavior to the structural flow of information, which reduces the risks of exploitation faced by the second-mover. Additionally, we analyze the impact of the second-mover's temptation payoff and pay off risks on the rate of cooperative behavior.
Detecting the limits of regulatory element conservation and divergence estimation using pairwise and multiple alignments
Authors: Pollard Daniel A , Moses Alan M , Iyer Venky N , Eisen Michael B
Published: August 2006

Background

Molecular evolutionary studies of noncoding sequences rely on multiple alignments. Yet how multiple alignment accuracy varies across sequence types, tree topologies, divergences and tools, and further how this variation impacts specific inferences, remains unclear.

Results

Here we develop a molecular evolution simulation platform, CisEvolver, with models of background noncoding and transcription factor binding site evolution, and use simulated alignments to systematically examine multiple alignment accuracy and its impact on two key molecular evolutionary inferences: transcription factor binding site conservation and divergence estimation. We find that the accuracy of multiple alignments is determined almost exclusively by the pairwise divergence distance of the two most diverged species and that additional species have a negligible influence on alignment accuracy. Conserved transcription factor binding sites align better than surrounding noncoding DNA yet are often found to be misaligned at relatively short divergence distances, such that studies of binding site gain and loss could easily be confounded by alignment error. Divergence estimates from multiple alignments tend to be overestimated at short divergence distances but reach a tool specific divergence at which they cease to increase, leading to underestimation at long divergences. Our most striking finding was that overall alignment accuracy, binding site alignment accuracy and divergence estimation accuracy vary greatly across branches in a tree and are most accurate for terminal branches connecting sister taxa and least accurate for internal branches connecting sub-alignments.

Conclusion

Our results suggest that variation in alignment accuracy can lead to errors in molecular evolutionary inferences that could be construed as biological variation. These findings have implications for which species to choose for analyses, what kind of errors would be expected for a given set of species and how multiple alignment tools and phylogenetic inference methods might be improved to minimize or control for alignment errors.
V-MitoSNP: visualization of human mitochondrial SNPs
Authors: Chuang Li-Yeh , Yang Cheng-Hong , Cheng Yu-Huei , Gu De-Leung , Chang Phei-Lang , Tsui Ke-Hung , Chang Hsueh-Wei
Published: August 2006

Background

Mitochondrial single nucleotide polymorphisms (mtSNPs) constitute important data when trying to shed some light on human diseases and cancers. Unfortunately, providing relevant mtSNP genotyping information in mtDNA databases in a neatly organized and transparent visual manner still remains a challenge. Amongst the many methods reported for SNP genotyping, determining the restriction fragment length polymorphisms (RFLPs) is still one of the most convenient and cost-saving methods. In this study, we prepared the visualization of the mtDNA genome in a way, which integrates the RFLP genotyping information with mitochondria related cancers and diseases in a user-friendly, intuitive and interactive manner. The inherent problem associated with mtDNA sequences in BLAST of the NCBI database was also solved.

Description

V-MitoSNP provides complete mtSNP information for four different kinds of inputs: (1) color-coded visual input by selecting genes of interest on the genome graph, (2) keyword search by locus, disease and mtSNP rs# ID, (3) visualized input of nucleotide range by clicking the selected region of the mtDNA sequence, and (4) sequences mtBLAST. The V-MitoSNP output provides 500 bp (base pairs) flanking sequences for each SNP coupled with the RFLP enzyme and the corresponding natural or mismatched primer sets. The output format enables users to see the SNP genotype pattern of the RFLP by virtual electrophoresis of each mtSNP. The rate of successful design of enzymes and primers for RFLPs in all mtSNPs was 99.1%. The RFLP information was validated by actual agarose electrophoresis and showed successful results for all mtSNPs tested. The mtBLAST function in V-MitoSNP provides the gene information within the input sequence rather than providing the complete mitochondrial chromosome as in the NCBI BLAST database. All mtSNPs with rs number entries in NCBI are integrated in the corresponding SNP in V-MitoSNP.

Conclusion

V-MitoSNP is a web-based software platform that provides a user-friendly and interactive interface for mtSNP information, especially with regard to RFLP genotyping. Visual input and output coupled with integrated mtSNP information from MITOMAP and NCBI make V-MitoSNP an ideal and complete visualization interface for human mtSNPs association studies.
A general pipeline for the development of anchor markers for comparative genomics in plants
Authors: Fredslund Jakob , Madsen Lene H , Hougaard Birgit K , Nielsen Anna Marie , Bertioli David , Sandal Niels , Stougaard Jens , Schauser Leif
Published: August 2006

Background

Complete or near-complete genomic sequence information is presently only available for a few plant species representing a large phylogenetic diversity among plants. In order to effectively transfer this information to species lacking sequence information, comparative genomic tools need to be developed. Molecular markers permitting cross-species mapping along co-linear genomic regions are central to comparative genomics. These "anchor" markers, defining unique loci in genetic linkage maps of multiple species, are gene-based and possess a number of features that make them relatively sparse. To identify potential anchor marker sequences more efficiently, we have established an automated bioinformatic pipeline that combines multi-species Expressed Sequence Tags (EST) and genome sequence data.

Results

Taking advantage of sequence data from related species, the pipeline identifies evolutionarily conserved sequences that are likely to define unique orthologous loci in most species of the same phylogenetic clade. The key features are the identification of evolutionarily conserved sequences followed by automated design of intron-flanking Polymerase Chain Reaction (PCR) primer pairs. Polymorphisms can subsequently be identified by size- or sequence variation of PCR products, amplified from mapping parents or populations. We illustrate our procedure in legumes and grasses and exemplify its application in legumes, where model plant studies and the genome- and EST-sequence data available have a potential impact on the breeding of crop species and on our understanding of the evolution of this large and diverse family.

Conclusion

We provide a database of 459 candidate anchor loci which have the potential to serve as map anchors in more than 18,000 legume species, a number of which are of agricultural importance. For grasses, the database contains 1335 candidate anchor loci. Based on this database, we have evaluated 76 candidate anchor loci with respect to marker development in legume species with no sequence information available, demonstrating the validity of this approach.