bluuebunny/crossref_metadata_2025_split huggingface dataset:
New and Sensitive Assay for Determining
Pseudomonas aeruginosa
Metallo-Beta-Lactamase Resistance to Imipenem
Authors: Tan Jingyuan , Pitout Johann D. D. , Guttman David S. 
Published: March 2008

ABSTRACT
We present an imipenem lysate metallo-beta-lactamase (MBL) functional assay. This assay eliminates false-positive results due to the bactericidal effects of EDTA, can be performed with inexpensive reagents available in most laboratories, and is as accurate as the MBL Etest. It is appropriate for both high-accuracy screens and laboratories in developing countries with limited resources.
Stability of
Trichomonas vaginalis
DNA in Urine Specimens
Authors: Ingersoll Jessica , Bythwood Tameka , Abdul-Ali Deborah , Wingood Gina M. , Diclemente Ralph J. , Caliendo Angela M. 
Published: March 2008

ABSTRACT

Trichomonas vaginalis
is an important pathogen in both men and women. Culture is considered the diagnostic gold standard, although studies have shown that PCR is more sensitive than either culture or wet mount for the diagnosis of
T. vaginalis
infections. We sought to identify a simple method for stabilizing
T. vaginalis
DNA in urine samples that could be easily applied to molecular testing. The stability of
T. vaginalis
DNA in 40 urine samples was assessed by storage for various times at either 4°C or room temperature with or without the Becton Dickinson urine preservative transport (UPT) kit. Overall, there was better stability of
T. vaginalis
DNA when specimens were stored at 4°C than when they were stored at 20 to 22°C and when the UPT system was used.
T. vaginalis
DNA was stable in specimens stored without using the UPT at 4°C for about 3 days and at room temperature for only 1 day. For specimens placed in the UPT within 24 h (times of 1, 6, and 24 h) of collection, the DNA was stable for up to 30 days when stored at 4°C. For specimens stored at room temperature, the urine should be added to the UPT ideally within 1 hour of collection, and in this case the DNA remained stable for up to 30 days. When storing specimens at room temperature, a delay of 24 h prior to adding to UPT led to an unacceptably high loss of assay sensitivity.
Histone Hyperacetylation Occurs on Promoters of Lytic Cycle Regulatory Genes in Epstein-Barr Virus-Infected Cell Lines Which Are Refractory to Disruption of Latency by Histone Deacetylase Inhibitors
Authors: Countryman Jill K. , Gradoville Lyndle , Miller George 
Published: March 2008

ABSTRACT
Activation of the Epstein-Barr virus (EBV) lytic cycle is mediated through the combined actions of ZEBRA and Rta, the products of the viral BZLF1 and BRLF1 genes. During latency, these two genes are tightly repressed. Histone deacetylase inhibitors (HDACi) can activate viral lytic gene expression. Therefore, a widely held hypothesis is that Zp and Rp, the promoters for BZLF1 and BRLF1, are repressed by chromatin and that hyperacetylation of histone tails, by allowing the access of positively acting factors, leads to transcription of BZLF1 and BRLF1. To investigate this hypothesis, we used chromatin immunoprecipitation (ChIP) to examine the acetylation and phosphorylation states of histones H3 and H4 on Zp and Rp in three cell lines, Raji, B95-8, and HH514-16, which differ in their response to EBV lytic induction by HDACi. We studied the effects of three HDACi, sodium butyrate (NaB), trichostatin A (TSA), and valproic acid (VPA). We also examined the effects of tetradecanoyl phorbol acetate (TPA) and 5-aza-2′-deoxycytidine, a DNA methyltransferase inhibitor, on histone modification. In Raji cells, TPA and NaB act synergistically to activate the EBV lytic cycle and promote an increase in histone H3 and H4 acetylation and phosphorylation at Zp and Rp. Surprisingly, however, when Raji cells were treated with NaB or TSA, neither of which is sufficient to activate the lytic cycle, an increase of comparable magnitude of hyperacetylated and phosphorylated histone H3 at Zp and Rp was observed. In B95-8 cells, NaB inhibited lytic induction by TPA, yet NaB promoted hyperacetylation of H3 and H4. In HH514-16 cells, NaB and TSA strongly activated the EBV lytic cycle and caused hyperacetylation of histone H3 on Zp and Rp. However, when HH514-16 cells were treated with VPA, lytic cycle mRNAs or proteins were not induced, although histone H3 was hyperacetylated as measured by immunoblotting or by ChIP on Zp and Rp. Taken together, our data suggest that open chromatin at EBV BZLF1 and BRLF1 promoters is not sufficient to activate EBV lytic cycle gene expression.
Cloning of the Koi Herpesvirus Genome as an Infectious Bacterial Artificial Chromosome Demonstrates That Disruption of the Thymidine Kinase Locus Induces Partial Attenuation in
Cyprinus carpio koi
Authors: Costes B. , Fournier G. , Michel B. , Delforge C. , Raj V. Stalin , Dewals B. , Gillet L. , Drion P. , Body A. , Schynts F. , Lieffrig F. , Vanderplasschen A. 
Published: March 2008

ABSTRACT

Koi herpesvirus (KHV) is the causative agent of a lethal disease in koi and common carp. In the present study, we describe the cloning of the KHV genome as a stable and infectious bacterial artificial chromosome (BAC) clone that can be used to produce KHV recombinant strains. This goal was achieved by the insertion of a
loxP
-flanked BAC cassette into the thymidine kinase (TK) locus. This insertion led to a BAC plasmid that was stably maintained in bacteria and was able to regenerate virions when permissive cells were transfected with the plasmid. Reconstituted virions free of the BAC cassette but carrying a disrupted TK locus (the FL BAC-excised strain) were produced by the transfection of Cre recombinase-expressing cells with the BAC. Similarly, virions with a wild-type revertant TK sequence (the FL BAC revertant strain) were produced by the cotransfection of cells with the BAC and a DNA fragment encoding the wild-type TK sequence. Reconstituted recombinant viruses were compared to the wild-type parental virus in vitro and in vivo. The FL BAC revertant strain and the FL BAC-excised strain replicated comparably to the parental FL strain. The FL BAC revertant strain induced KHV infection in koi carp that was indistinguishable from that induced by the parental strain, while the FL BAC-excised strain exhibited a partially attenuated phenotype. Finally, the usefulness of the KHV BAC for recombination studies was demonstrated by the production of an ORF16-deleted strain by using prokaryotic recombination technology. The availability of the KHV BAC is an important advance that will allow the study of viral genes involved in KHV pathogenesis, as well as the production of attenuated recombinant candidate vaccines.
The Thiazolobenzimidazole TBZE-029 Inhibits Enterovirus Replication by Targeting a Short Region Immediately Downstream from Motif C in the Nonstructural Protein 2C
Authors: De Palma Armando M. , Heggermont Ward , Lanke Kjerstin , Coutard Bruno , Bergmann Mirko , Monforte Anna-Maria , Canard Bruno , De Clercq Erik , Chimirri Alba , Pürstinger Gerhard , Rohayem Jacques , van Kuppeveld Frank , Neyts Johan 
Published: March 2008

ABSTRACT

TBZE-029 {1-(2,6-difluorophenyl)-6-trifluoromethyl-1
H
,3
H
-thiazolo[3,4-a]benzimidazole} is a novel selective inhibitor of the replication of several enteroviruses. We show that TBZE-029 exerts its antiviral activity through inhibition of viral RNA replication, without affecting polyprotein processing. To identify the viral target of TBZE-029, drug-resistant coxsackievirus B3 (CVB3) was selected. Genotyping of resistant clones led to the identification of three amino acid mutations in nonstructural protein 2C, clustered at amino acid positions 224, 227, and 229, immediately downstream of NTPase/helicase motif C. The mutations were reintroduced, either alone or combined, into an infectious full-length CVB3 clone. In particular the mutations at positions 227 and 229 proved essential for the altered sensitivity of CVB3 to TBZE-029. Resistant virus exhibited cross-resistance to the earlier-reported antienterovirus agents targeting 2C, namely, guanidine hydrochloride, HBB [2-(alpha-hydroxybenzyl)-benzimidazole], and MRL-1237 {1-(4-fluorophenyl)-2-[(4-imino-1,4-dihydropyridin-1-yl)methyl]benzimidazole hydrochloride}. The ATPase activity of 2C, however, remained unaltered in the presence of TBZE-029.
Generation of Antiviral Major Histocompatibility Complex Class I-Restricted T Cells in the Absence of CD8 Coreceptors
Authors: Andrews Nicolas P. , Pack Christopher D. , Lukacher Aron E. 
Published: March 2008

ABSTRACTThe CD8 coreceptor is important for positive selection of major histocompatibility complex I (MHC-I)-restricted thymocytes and in the generation of pathogen-specific T cells. However, the requirement for CD8 in these processes may not be essential. We previously showed that mice lacking β2-microglobulin are highly susceptible to tumors induced by mouse polyoma virus (PyV), but CD8-deficient mice are resistant to these tumors. In this study, we show that CD8-deficient mice also control persistent PyV infection as efficiently as wild-type mice and generate a substantial virus-specific, MHC-I-restricted, T-cell response. Infection with vesicular stomatitis virus (VSV), which is acutely cleared, also recruited antigen-specific, MHC-I-restricted T cells in CD8-deficient mice. Yet, unlike in VSV infection, the antiviral MHC-I-restricted T-cell response to PyV has a prolonged expansion phase, indicating a requirement for persistent infection in driving T-cell inflation in CD8-deficient mice. Finally, we show that the PyV-specific, MHC-I-restricted T cells in CD8-deficient mice, while maintained long term at near-wild-type levels, are short lived in vivo and have extremely narrow T-cell receptor repertoires. These findings provide a possible explanation for the resistance of CD8-deficient mice to PyV-induced tumors and have implications for the maintenance of virus-specific MHC-I-restricted T cells during persistent infection.
CX3CR1 Is Expressed by Prostate Epithelial Cells and Androgens Regulate the Levels of CX3CL1/Fractalkine in the Bone Marrow: Potential Role in Prostate Cancer Bone Tropism
Authors: Jamieson Whitney L. , Shimizu Saori , D'Ambrosio Julia A. , Meucci Olimpia , Fatatis Alessandro 
Published: March 2008

Abstract
We have previously shown that the chemokine fractalkine promotes the adhesion of human prostate cancer cells to bone marrow endothelial cells as well as their migration toward human osteoblasts in vitro. Thus, the interaction of fractalkine with its receptor CX3CR1 could play a crucial role in vivo by directing circulating prostate cancer cells to the bone. We found that although CX3CR1 is minimally detectable in epithelial cells of normal prostate glands, it is overexpressed upon malignant transformation. Interestingly, osteoblasts, stromal and mesenchymal cells derived from human bone marrow aspirates express the cell-bound form of fractalkine, whereas the soluble form of the chemokine is detected in bone marrow supernatants. To investigate the mechanisms regulating the levels of soluble fractalkine in the bone marrow, we focused on androgens, which play a critical role in both prostate cancer progression and skeletal metastasis. Here, we show that dihydrotestosterone dramatically increases the cleavage of fractalkine from the plasma membrane of bone cells and its action is reversed by nilutamide—an antagonist of the androgen receptor—as well as the wide-spectrum inhibitor of matrix metalloproteases, GM6001. However, dihydrotestosterone was unable to induce fractalkine-cleavage from human bone marrow endothelial cells. Thus, androgens could promote the extravasation of CX3CR1-bearing cancer cells on a fractalkine concentration gradient, while leaving unaltered their ability to adhere to the bone marrow endothelium. In conclusion, our results indicate that CX3CR1, fractalkine, and the enzymes responsible for its cleavage might represent suitable targets for therapies aiming to counteract skeletal secondary tumors from prostate adenocarcinoma. [Cancer Res 2008;68(6):1715–22]
Rad6B Is a Positive Regulator of β-Catenin Stabilization
Authors: Shekhar Malathy P.V. , Gerard Brigitte , Pauley Robert J. , Williams Bart O. , Tait Larry 
Published: March 2008

Abstract
Mutations in β-catenin or other Wnt pathway components that cause β-catenin accumulation occur rarely in breast cancer. However, there is some evidence of β-catenin protein accumulation in a subset of breast tumors. We have recently shown that Rad6B, an ubiquitin-conjugating enzyme, is a transcriptional target of β-catenin/TCF. Here, we show that forced Rad6B overexpression in MCF10A breast cells induces β-catenin accumulation, which despite being ubiquitinated is stable and transcriptionally active. A similar relationship between Rad6B, β-catenin ubiquitination, and transcriptional activity was found in WS-15 and MDA-MB-231 breast cancer cells, and mouse mammary tumor virus–Wnt-1 mammary tumor—derived cells, implicating Rad6B in physiologic regulation of β-catenin stability and activity. Ubiquitinated β-catenin was detectable in chromatin immunoprecipitations performed with β-catenin antibody in MDA-MB-231 but not MCF10A cells. Rad6B silencing caused suppression of β-catenin monoubiquitination and polyubiquitination, and transcriptional activity. These effects were accompanied by a reduction in intracellular β-catenin but with minimal effects on cell membrane–associated β-catenin. Measurement of β-catenin protein stability by cycloheximide treatment showed that Rad6B silencing specifically decreases the stability of high molecular β-catenin with minimal effect upon the 90-kDa nascent form. In vitro ubiquitination assays confirmed that Rad6B mediates β-catenin polyubiquitination, and ubiquitin chain extensions involve lysine 63 residues that are insensitive to 26S proteasome. These findings, combined with our previous data that Rad6B is a transcriptional target of β-catenin, reveal a positive regulatory feedback loop between Rad6B and β-catenin and a novel mechanism of β-catenin stabilization/activation in breast cancer cells. [Cancer Res 2008;68(6):1741–50]
Regulation of CXCR4 by the Notch Ligand Delta-like 4 in Endothelial Cells
Authors: Williams Cassin Kimmel , Segarra Marta , De La Luz Sierra Maria , Sainson Richard C.A. , Tosato Giovanna , Harris Adrian L. 
Published: March 2008

Abstract
Gene-targeting studies have shown that Delta-like 4 (Dll4) is required for normal embryonic vascular remodeling, but the mechanisms underlying Dll4 regulatory functions are not well defined. We generated primary human umbilical vascular endothelial cells that express Dll4 protein to study Dll4 function and previously showed that Dll4 down-regulates vascular endothelial growth factor (VEGF) receptor 2 and NRP1 expression and inhibits VEGF function. We now report that expression of Dll4 in endothelial cells inhibited attachment and migration to stromal-derived growth factor 1 (SDF1) chemokine. Cell surface, total protein, and mRNA levels of CXCR4, principal signaling receptor for SDF1, were significantly decreased in Dll4-transduced endothelial cells, attributable to a significant reduction of CXCR4 promoter activity. An immobilized recombinant extracellular portion of Dll4 (rhDLL4) was sufficient to down-regulate CXCR4 mRNA and protein, whereas protein levels of SDF1, VEGF, and RDC1 were unchanged. The γ-secretase inhibitor L-685,458 significantly reconstituted CXCR4 mRNA in rhDLL4-stimulated endothelial cells. CXCR4 mRNA levels were significantly reduced in mouse xenografts of Dll4-transduced human gliomas compared with control gliomas, and vascular CXCR4 was not detected by immunohistochemistry in the enlarged vessels within the Dll4 gliomas. Thus, Dll4 may contribute to vascular differentiation and inhibition of the angiogenic response by regulating multiple receptor pathways. [Cancer Res 2008;68(6):1889–95]
AXL Is a Potential Target for Therapeutic Intervention in Breast Cancer Progression
Authors: Zhang Yi-Xiang , Knyazev Peter G. , Cheburkin Yuri V. , Sharma Kirti , Knyazev Yuri P. , Őrfi László , Szabadkai István , Daub Henrik , Kéri György , Ullrich Axel 
Published: March 2008

Abstract
Protein kinases play important roles in tumor development and progression. A variety of members of this family of signal transduction enzymes serve as targets for therapeutic intervention in cancer. We have identified the receptor tyrosine kinase (RTK) AXL as a potential mediator of motility and invasivity of breast cancer cells. AXL is expressed in most highly invasive breast cancer cells, but not in breast cancer cells of low invasivity. Ectopic expression of AXL was sufficient to confer a highly invasive phenotype to weakly invasive MCF7 breast cancer cells. Experimental inhibition of AXL signaling by a dominant-negative AXL mutant, an antibody against the extracellular domain of AXL, or short hairpin RNA knockdown of AXL decreased motility and invasivity of highly invasive breast cancer cells. To selectively interfere with cancer cell properties defining the rate of disease progression, we identified 3-quinolinecarbonitrile compounds, which displayed potent inhibitory activity against AXL and showed strong interference with motility and invasivity of breast cancer cells. Our findings validated the RTK AXL as a critical element in the signaling network that governs motility and invasivity of breast cancer cells, and allowed the identification of experimental anti-AXL small molecular inhibitors that represent lead substances for the development of antimetastatic breast cancer therapy. [Cancer Res 2008;68(6):1905–15]
Kaposi's Sarcoma–Associated Herpesvirus Viral IFN Regulatory Factor 3 Stabilizes Hypoxia-Inducible Factor-1α to Induce Vascular Endothelial Growth Factor Expression
Authors: Shin Young C. , Joo Chul-Hyun , Gack Michaela U. , Lee Hye-Ra , Jung Jae U. 
Published: March 2008

Abstract
Kaposi's sarcoma–associated herpesvirus (KSHV) is the etiologic agent associated with Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman's disease. Hypoxia-inducible factor-1 (HIF-1) is the master regulator of both developmental and pathologic angiogenesis, composed of an oxygen-sensitive α-subunit and a constitutively expressed β-subunit. HIF-1 activity in tumors depends on the availability of the HIF-1α subunit, the levels of which are increased under hypoxic conditions. Recent studies have shown that HIF-1 plays an important role in KSHV reactivation from latency and pathogenesis. Here, we report a novel mechanism by which KSHV activates HIF-1 activity. Specific interaction between KSHV viral IFN regulatory factor 3 (vIRF3) and the HIF-1α subunit led to the HIF-1α stabilization and transcriptional activation, which induced vascular endothelial growth factor expression and ultimately facilitated endothelial tube formation. Remarkably, the central domain of vIRF3, containing double α-helix motifs, was sufficient not only for binding to HIF-1α but also for blocking its degradation in normoxic conditions. This indicates that KSHV has developed a unique mechanism to enhance HIF-1α protein stability and transcriptional activity by incorporating a viral homologue of cellular IRF gene into its genome, which may contribute to viral pathogenesis. [Cancer Res 2008;68(6):1751–9]
14-3-3ζ Down-regulates p53 in Mammary Epithelial Cells and Confers Luminal Filling
Authors: Danes Christopher G. , Wyszomierski Shannon L. , Lu Jing , Neal Christopher L. , Yang Wentao , Yu Dihua 
Published: March 2008

Abstract
Recent progress in diagnostic tools allows many breast cancers to be detected at an early preinvasive stage. Thus, a better understanding of the molecular basis of early breast cancer progression is essential. Previously, we discovered that 14-3-3ζ is overexpressed in &gt;40% of advanced breast cancers, and this overexpression predicts poor patient survival. Here, we examined at what stage of breast disease 14-3-3ζ overexpression occurs, and we found that increased expression of 14-3-3ζ begins at atypical ductal hyperplasia, an early stage of breast disease. To determine whether 14-3-3ζ overexpression is a decisive early event in breast cancer, we overexpressed 14-3-3ζ in MCF10A cells and examined its effect in a three-dimensional culture model. We discovered that 14-3-3ζ overexpression severely disrupted the acini architecture resulting in luminal filling. Proper lumen formation is a result of anoikis, apoptosis due to detachment from the basement membrane. We found that 14-3-3ζ overexpression conferred resistance to anoikis. Additionally, 14-3-3ζ overexpression in MCF10A cells and in mammary epithelial cells (MEC) from 14-3-3ζ transgenic mice reduced expression of p53, which is known to mediate anoikis. Mechanistically, 14-3-3ζ induced hyperactivation of the phosphoinositide 3-kinase/Akt pathway which led to phosphorylation and translocation of the MDM2 E3 ligase resulting in increased p53 degradation. Ectopic expression of p53 restored luminal apoptosis in 14-3-3ζ–overexpressing MCF10A acini in three-dimensional cultures. These data suggest that 14-3-3ζ overexpression is a critical event in early breast disease, and down-regulation of p53 is one of the mechanisms by which 14-3-3ζ alters MEC acini structure and increases the risk of breast cancer. [Cancer Res 2008;68(6):1760–7]
Mammalian Target of Rapamycin Repression by 3,3′-Diindolylmethane Inhibits Invasion and Angiogenesis in Platelet-Derived Growth Factor-D–Overexpressing PC3 Cells
Authors: Kong Dejuan , Banerjee Sanjeev , Huang Wei , Li Yiwei , Wang Zhiwei , Kim Hyeong-Reh Choi , Sarkar Fazlul H. 
Published: March 2008

Abstract
Platelet-derived growth factor-D (PDGF-D) is a newly recognized growth factor known to regulate many cellular processes, including cell proliferation, transformation, invasion, and angiogenesis. Recent studies have shown that PDGF-D and its cognate receptor PDGFR-β are expressed in prostate tumor tissues, suggesting that PDGF-D might play an important role in the development and progression of prostate cancer. However, the biological role of PDGF-D in tumorigenesis remains elusive. In this study, we found that PDGF-D–overexpressing PC3 cells (PC3 cells stably transfected with PDGF-D cDNA and referred to as PC3 PDGF-D) exhibited a rapid growth rate and enhanced cell invasion that was associated with the activation of mammalian target of rapamycin (mTOR) and reduced Akt activity. Rapamycin repressed mTOR activity and concomitantly resulted in the activation of Akt, which could attenuate the therapeutic effects of mTOR inhibitors. In contrast, B-DIM (BR-DIM from Bioresponse, Inc.; a chemopreventive agent) significantly inhibited both mTOR and Akt in PC3 PDGF-D cells, which were correlated with decreased cell proliferation and invasion. Moreover, conditioned medium from PC3 PDGF-D cells significantly increased the tube formation of human umbilical vein endothelial cells, which was inhibited by B-DIM treatment concomitant with reduced full-length and active form of PDGF-D. Our results suggest that B-DIM could serve as a novel and efficient chemopreventive and/or therapeutic agent by inactivation of both mTOR and Akt activity in PDGF-D–overexpressing prostate cancer. [Cancer Res 2008;68(6):1927–34]