bluuebunny/crossref_metadata_2025 huggingface dataset:
Vascular endothelial growth factor does not improve liver regeneration and survival after 90% subtotal liver resection
Authors: Bockhorn Maximilian , Schöllmann Stefanie , Opitz Bettina , Sotiropoulos Georgious C. , Sheu Sien‐Yi , Niehaus Eva , Trippler Martin , Frilling Andreja , Broelsch Christoph E. , Schlaak Jörg F.
Published: April 2007

Aim:  Vascular endothelial growth factor (VEGF) has been shown to stimulate liver regeneration after 70% partial hepatectomy (PH). It is unclear, however, whether exogenous administration of VEGF can also be used to improve liver regeneration and survival after 90% subtotal liver resection. The aim of this study was to determine the effect of exogenous and endogenous VEGF after 90% subtotal hepatectomy (SH).

Methods:  Rats were subjected to 90% SH and treated with VEGF, anti‐VEGF or NaCl. Postoperatively (3 h – 5 days) liver body weight ratio (LBR), hepatocyte proliferation and biochemical markers were assessed. ELISA was performed to measure protein levels for VEGF. Gene expression was determined by customized cDNA arrays and quantitative RT‐PCR.

Results:  Administration of VEGF did not enhance LBR or hepatic proliferation, or reduce the serum parameters. VEGF levels were the highest in VEGF‐treated animals. The overall survival after 90% SH reached 78% in VEGF‐treated animals, but did not differ significantly from that of anti‐VEGF or NaCl‐treated animals (74% and 75%, respectively). Gene expression analysis showed a modulation of anti‐apoptotic and cell cycle control genes that was independent of VEGF.

Conclusions:  In contrast to PH, liver regeneration and survival after SH cannot be modulated by VEGF. This indicates that the relevant mechanisms that stimulate liver regeneration after hepatectomy at least partially depend upon the extent of liver resection.
Paradoxical Effect of Echinocandins across
Candida
Species In Vitro: Evidence for Echinocandin-Specific and
Candida
Species-Related Differences
Authors: Chamilos Georgios , Lewis Russell E. , Albert Nathaniel , Kontoyiannis Dimitrios P.
Published: April 2007

Paradoxical growth of some
Candida
isolates occurs at concentrations above the MIC for echinocandins. In 60
Candida
bloodstream isolates from cancer patients (20
C. albicans
isolates and 10 isolates each of
C. parapsilosis
,
C. tropicalis
,
C. krusei
, and
C. glabrata
), paradoxical growth was more frequent with caspofungin than micafungin or anidulafungin, was unrelated to MIC, and was strikingly absent in
C. glabrata
isolates.
Isoniazid Bactericidal Activity and Resistance Emergence: Integrating Pharmacodynamics and Pharmacogenomics To Predict Efficacy in Different Ethnic Populations
Authors: Gumbo Tawanda , Louie Arnold , Liu Weiguo , Brown David , Ambrose Paul G. , Bhavnani Sujata M. , Drusano George L.
Published: April 2007

Isoniazid, administered as part of combination antituberculosis therapy, is responsible for most of the early bactericidal activity (EBA) of the regimen. However, the emergence of
Mycobacterium tuberculosis
resistance to isoniazid is a major problem. We examined the relationship between isoniazid exposure and
M. tuberculosis
microbial kill, as well as the emergence of resistance, in our in vitro pharmacodynamic model of tuberculosis. Since single-nucleotide polymorphisms of the
N
-acetyltransferase-2 gene lead to two different clearances of isoniazid from serum in patients, we simulated the isoniazid concentration-time profiles encountered in both slow and fast acetylators. Both microbial kill and the emergence of resistance during monotherapy were associated with the ratio of the area under the isoniazid concentration-time curve from 0 to 24 h (AUC
0-24
) to the isoniazid MIC. The time in mutant selection window hypothesis was rejected. Next, we utilized the in vitro relationship between the isoniazid AUC
0-24
/MIC ratio and microbial kill, the distributions of isoniazid clearance in populations with different percentages of slow and fast acetylators, and the distribution of isoniazid MICs for isonazid-susceptible
M. tuberculosis
clinical isolates in Monte Carlo simulations to calculate the EBA expected for ∼10,000 patients treated with 300 mg of isoniazid. For those patient populations in which the proportion of fast acetylators and the isoniazid MICs were high, the average EBA of the standard dose was ∼0.3 log
10
CFU/ml/day and was thus suboptimal. Our approach, which utilizes preclinical pharmacodynamics and the genetically determined multimodal distributions of serum clearances, is a preclinical tool that may be able to predict the EBAs of various doses of new antituberculosis drugs.
Transient Loss of High-Level Mupirocin Resistance in
Staphylococcus aureus
Due to MupA Polymorphism
Authors: Driscoll Daniel G. , Young Casey L. , Ochsner Urs A.
Published: April 2007

Spontaneous loss of MupA-mediated high-level mupirocin resistance was observed in
Staphylococcus aureus
, although the isolate gave a PCR-positive test result for
mupA
. Sequencing of the
mupA
gene identified a single base-pair deletion that resulted in a frameshift mutation and loss of functional protein. Reversion to the wild-type allele and restoration of high-level resistance occurred with high frequency (>10
−6
), indicating the transient nature of MupA polymorphism.
Evidence and Possible Consequences of the Phosphorylation of Nucleoside Reverse Transcriptase Inhibitors in Human Red Blood Cells
Authors: Durand-Gasselin Lucie , Da Silva David , Benech Henri , Pruvost Alain , Grassi Jacques
Published: April 2007

The intracellular metabolism of nucleoside reverse transcriptase inhibitors (NRTI) in mononuclear cells has been thoroughly studied, but that in red blood cells (RBC) has been disregarded. However, the phosphorylation of other analogous nucleosides (in particular, ribavirin) has been described previously. In this study, we investigated for the first time the phosphorylation of NRTI in human RBC. The presence of intracellular zidovudine (AZT) monophosphate, AZT triphosphate, lamivudine (3TC) triphosphate, and tenofovir (TFV) diphosphate, as well as endogenous dATP, dGTP, and dTTP, in RBC collected from human immunodeficiency virus-infected patients was examined. We observed evidence of a selective phosphorylation of 3TC, TFV, and endogenous purine deoxynucleosides to generate their triphosphate moieties. Conversely, no trace of AZT phosphate metabolites was found, and only faint dTTP signals were visible. A comparison of intracellular TFV diphosphate and 3TC triphosphate levels in RBC and peripheral blood mononuclear cells (PBMC) further highlighted the specificity of NRTI metabolism in each cell type. These findings raise the issue of RBC involvement in drug-drug interaction, drug pharmacokinetics, and drug-induced toxicity. Moreover, the typical preparation of PBMC samples by gradient density centrifugation does not prevent their contamination with RBC. We demonstrated that the presence of RBC within PBMC hampers an accurate determination of intracellular TFV diphosphate and dATP levels in clinical PBMC samples. Thus, we recommend removing RBC during PBMC preparation by using an ammonium chloride solution to enhance both the accuracy and the precision of intracellular drug monitoring.
In Vitro Susceptibility of
Sporothrix schenckii
to Six Antifungal Agents Determined Using Three Different Methods
Authors: Alvarado-Ramírez Eidi , Torres-Rodríguez Josep M.
Published: April 2007

The in vitro susceptibility of
Sporothrix schenckii
to antifungal drugs has been determined with three different methods. Nineteen Peruvian clinical isolates of
S. schenckii
were tested against amphotericin B (AB), flucytosine (FC), fluconazole (FZ), itraconazole (IZ), voriconazole (VZ), and ketoconazole (KZ). Modified NCCLS M38-A, Sensititre YeastOne (SYO), and ATB Fungus 2 (ATBF2) methods were used to determine the MICs. ATCC isolates of
Candida parapsilosis
,
Candida krusei
, and
Aspergillus flavus
were used for quality control.
Sporothrix
inocula were prepared with the mycelial form growing on potato dextrose agar at 28 ± 2°C. MICs of AB, FC, FZ, and IZ were determined with all three methods, VZ with M38-A and SYO, and KZ with only SYO. The three methods showed high MICs of FZ and FC (MIC
90
of 0.5 μg/ml), being homogeneously lower than those of IZ and KZ. The M38-A method showed a variable MIC range of VZ (4.0 to 16 μg/ml); the geometric mean (GM) was 9.3 μg/ml. The MIC range of AB was wide (0.06 to 16 μg/ml), but the GM was 1.2 μg/ml, suggesting that the MIC is strain dependent. Agreement (two log
2
dilutions) between commercial techniques and the modified M38-A method was very high with FZ, IZ, and FC. In AB and VZ, the agreement was lower, being related to the antifungal concentrations of each method. The highest activity against
S. schenckii
was found with IZ and KZ. Lack of activity was observed with FZ, VZ, and FC. When AB is indicated for sporotrichosis, the susceptibility of the strain must be analyzed. Commercial quantitative antifungal methods have a limited usefulness in
S. schenckii
.
Biochemical Characterization of PER-2 and Genetic Environment of
bla
PER-2
Authors: Power Pablo , Di Conza José , Rodríguez María Margarita , Ghiglione Bárbara , Ayala Juan A. , Casellas José María , Radice Marcela , Gutkind Gabriel
Published: April 2007

PER-2 was the first detected and the second most prevalent extended-spectrum β-lactamase in clinical pathogens isolated in Argentina and was also reported only in other South American countries.
Citrobacter freundii
33587 was isolated in 1999 in Buenos Aires and was resistant to all tested β-lactams except cephamycins and carbapenems. The strain produced both plasmid-borne TEM-1 and PER-2 (pI 5.4), which could be transferred by conjugation. By PCR screening, thermal asymmetric interlaced PCR, and DNA sequencing, we detected an IS
Pa12
/IS
1387a
insertion sequence upstream of
bla
PER-2
, previously reported as also being associated with
bla
PER-1
. The presence of similar structures upstream of
bla
PER-1
and
bla
PER-2
suggests a common origin and mobilization. Compared to
bla
PER-1
genes, an additional putative promoter for
bla
PER-2
was found. PER-2 kinetic analysis showed its high hydrolysis efficiencies toward both CTX and CAZ (
k
cat
/

K
m

, 0.76 and 0.43 μM
−1
·s
−1
, respectively).
Multicopy
bla
OXA-58
Gene as a Source of High-Level Resistance to Carbapenems in
Acinetobacter baumannii
Authors: Bertini Alessia , Poirel Laurent , Bernabeu Sandrine , Fortini Daniela , Villa Laura , Nordmann Patrice , Carattoli Alessandra
Published: April 2007

The mechanisms at the origin of heterogeneous carbapenem resistance levels observed among
Acinetobacter baumannii
isolates collected in 2005 in a large University Hospital of Rome, Italy, were investigated. These isolates were related and possessed similar plasmids carrying the carbapenem-hydrolyzing oxacillinase gene
bla
OXA-58
but showed variable levels of resistance to carbapenems. Analysis of sequences surrounding the
bla
OXA-58
gene showed genetic variability, with the presence in several isolates of multiple copies of the
bla
OXA-58
gene; this extra copy number was likely related to an IS
26
-mediated transposition or recombination process.
Role of Motility and the
flhDC
Operon in
Escherichia coli
MG1655 Colonization of the Mouse Intestine
Authors: Gauger Eric J. , Leatham Mary P. , Mercado-Lubo Regino , Laux David C. , Conway Tyrrell , Cohen Paul S.
Published: April 2007

Previously, we reported that the mouse intestine selected mutants of
Escherichia coli
MG1655 that have improved colonizing ability (M. P. Leatham et al., Infect. Immun.
73:
8039-8049, 2005). These mutants grew 10 to 20% faster than their parent in mouse cecal mucus in vitro and 15 to 30% faster on several sugars found in the mouse intestine. The mutants were nonmotile and had deletions of various lengths beginning immediately downstream of an IS
1
element located within the regulatory region of the
flhDC
operon, which encodes the master regulator of flagellum biosynthesis, FlhD
4
C
2
. Here we show that during intestinal colonization by wild-type
E. coli
strain MG1655, 45 to 50% of the cells became nonmotile by day 3 after feeding of the strain to mice and between 80 and 90% of the cells were nonmotile by day 15 after feeding. Ten nonmotile mutants isolated from mice were sequenced, and all were found to have
flhDC
deletions of various lengths. Despite this strong selection, 10 to 20% of the
E. coli
MG1655 cells remained motile over a 15-day period, suggesting that there is an as-yet-undefined intestinal niche in which motility is an advantage. The deletions appear to be selected in the intestine for two reasons. First, genes unrelated to motility that are normally either directly or indirectly repressed by FlhD
4
C
2
but can contribute to maximum colonizing ability are released from repression. Second, energy normally used to synthesize flagella and turn the flagellar motor is redirected to growth.
Invasion Pathways and Malaria Severity in Kenyan
Plasmodium falciparum
Clinical Isolates
Authors: Deans Anne-Marie , Nery Susana , Conway David J. , Kai Oscar , Marsh Kevin , Rowe J. Alexandra
Published: April 2007

The invasion of erythrocytes by
Plasmodium falciparum
occurs through multiple pathways that can be studied in vitro by examining the invasion of erythrocytes treated with enzymes such as neuraminidase, trypsin, and chymotrypsin. We have studied the invasion pathways used by 31 Kenyan
P. falciparum
isolates from children with uncomplicated or severe malaria. Six distinct invasion profiles were detected, out of eight possible profiles. The majority of isolates (23 of 31) showed neuraminidase-resistant, trypsin-sensitive invasion, characteristic of the pathway mediated by an unknown parasite ligand and erythrocyte receptor “X.” The neuraminidase-sensitive, trypsin-sensitive phenotype consistent with invasion mediated by the binding of parasite ligand erythrocyte binding antigen 175 to glycophorin A, the most common invasion profile in a previous study of Gambian field isolates, was seen in only 3 of 31 Kenyan isolates. No particular invasion profile was associated with severe
P. falciparum
malaria, and there was no significant difference in the levels of inhibition by the various enzyme treatments between isolates from children with severe malaria and those from children with uncomplicated malaria (
P
, >0.1 for all enzymes; Mann-Whitney U test). These results do not support the hypothesis that differences in invasion phenotypes play an important role in malaria virulence and indicate that considerable gaps remain in our knowledge of the molecular basis of invasion pathways in natural
P. falciparum
infections.
Expression and Cellular Localization of Molecules of the gp82 Family in
Trypanosoma cruzi
Metacyclic Trypomastigotes
Authors: Atayde Vanessa D. , Cortez Mauro , Souza Renata , da Silveira José Franco , Yoshida Nobuko
Published: April 2007

A member of the
Trypanosoma cruzi
gp82 family, expressed on metacyclic trypomastigote surface and identified by monoclonal antibody (MAb) 3F6, plays a key role in host cell invasion. Apart from the gp82 defined by MAb 3F6, no information is available on members of this protein family. From cDNA clones encoding gp82 proteins sharing 59.1% sequence identity, we produced the recombinant proteins J18 and C03, the former containing and the latter lacking the epitope for MAb 3F6. Polyclonal antibodies to J18 and C03 proteins were generated and used, along with MAb 3F6, to analyze the expression and cellular localization of gp82 family members in metacyclic forms of CL and G strains, which belong to highly divergent genetic groups. By two-dimensional gel electrophoresis and immunoblotting, molecules of 82 to 86 kDa, focusing at pH 4.6 to 5.4, and molecules of 72 to 88 kDa, focusing at pH 4.9 to 5.7, were visualized in CL and G strains, respectively. Flow cytometry and microscopic analysis revealed in both strains similar expression of MAb 3F6-reactive gp82 in live and permeabilized parasites, indicating its surface localization. The reaction of live parasites of both strains with anti-J18 antibodies was weaker than with MAb 3F6 and was increased by permeabilization. Anti-C03 antibodies bound predominantly to flagellar components in permeabilized G strain parasites, but in the CL strain the flagellum was not the preferential target for these antibodies. Host cell invasion of metacyclic forms was inhibited by J18 protein, as well as by MAb 3F6 and anti-J18 antibodies, but not by C03 protein or anti-C03 antibodies.
Evaluation of the Role of LcrV-Toll-Like Receptor 2-Mediated Immunomodulation in the Virulence of
Yersinia pestis
Authors: Pouliot Kimberly , Pan Ning , Wang Shixia , Lu Shan , Lien Egil , Goguen Jon D.
Published: April 2007

Pathogenic members of the
Yersinia
genus require the translocator protein LcrV for proper function of the type III secretion apparatus, which is crucial for virulence. LcrV has also been reported to play an independent immunosuppressive role via the induction of interleukin-10 (IL-10) through stimulation of Toll-like receptor 2 (TLR2). To investigate the LcrV-TLR2 interaction in vitro, His-tagged recombinant LcrV (rLcrV) from
Yersinia pestis
was cloned and expressed in
Escherichia coli
and purified through Ni-nitrilotriacetic acid column chromatography. High concentrations (5 μg/ml) of rLcrV stimulated TLR2 in vitro. Fractionation of rLcrV preparations via gel filtration revealed that only a minor component consisting of high-molecular-weight multimers or aggregates has TLR2 stimulating activity. Dimer and tetramer forms of rLcrV, which constitute the bulk of the material, do not have this activity. To investigate the potential role of LcrV/TLR2 in plague pathogenesis, we infected wild-type and TLR2
−/−
mice with virulent
Y. pestis
. No discernible difference between the two mouse strains in severity of disease or kinetics of survival after subcutaneous challenge was observed. IL-6, tumor necrosis factor, and IL-10 levels from spleen homogenates; bacterial load; and the extent of inflammation observed in organs from mice infected intravenously were also indistinguishable in both mouse strains. Taken together, our data indicate that the most abundant molecular species of
Y. pestis
LcrV do not efficiently activate TLR2-signaling and that TLR2-mediated immunomodulation is unlikely to play a significant role in plague.
Further Studies on Antioxidant Potential and Protection of Pancreatic β‐Cells by Embelia ribes in Experimental Diabetes
Authors: Bhandari Uma , Jain Neeti , Pillai K. K.
Published: April 2007

This study was designed to examine the antioxidant defense by ethanolic extract of Embelia ribes on streptozotocin‐(40 mg/kg, intravenously, single‐injection) induced diabetes in Wistar rats. Forty days of oral feeding the extract (100 mg/kg and 200 mg/kg) to diabetic rats resulted in significant (P < .01) decrease in blood glucose, blood glycosylated haemoglobin, serum lactate dehydrogenase, creatine kinase, and increase in blood glutathione levels as compared to pathogenic diabetic rats. Further, the extract also significantly (P < .01) decreased the pancreatic thiobarbituric acid‐reactive substances (TBARS) levels and significantly (P < .01) increased the superoxide dismutase, catalase, and glutathione levels as compared to above levels in pancreatic tissue of pathogenic diabetic rats. The islets were shrunken in diabetic rats in comparison to normal rats. In the drug‐treated diabetic rats, there was expansion of islets. The results of test drug were comparable to gliclazide (25 mg/kg, daily), a standard antihyperglycemic agent. The study concludes that Embelia ribes enhances the antioxidant defense against reactive oxygen species produced under hyperglycemic condition and this protects β‐cells against loss, and exhibit antidiabetic property.
Comparison of a Ring On-Chip Network and a Code-Division Multiple-Access On-Chip Network
Authors: Wang Xin , Nurmi Jari
Published: April 2007

Two network-on-chip (NoC) designs are examined and compared in this paper. One design applies a bidirectional ring connection scheme, while the other design applies a code-division multiple-access (CDMA) connection scheme. Both of the designs apply globally asynchronous locally synchronous (GALS) scheme in order to deal with the issue of transferring data in a multiple-clock-domain environment of an on-chip system. The two NoC designs are compared with each other by their network structures, data transfer principles, network node structures, and their asynchronous designs. Both the synchronous and the asynchronous designs of the two on-chip networks are realized using a hardware-description language (HDL) in order to make the entire designs suit the commonly used synchronous design tools and flow. The performance estimation and comparison of the two NoC designs which are based on the HDL realizations are addressed. By comparing the two NoC designs, the advantages and disadvantages of applying direct connection and CDMA connection schemes in an on-chip communication network are discussed.
A Method for Routing Packets Across Multiple Paths in NoCs with In-Order Delivery and Fault-Tolerance Gaurantees
Authors: Murali Srinivasan , Atienza David , Benini Luca , De Micheli Giovanni
Published: April 2007

Networks on Chips (NoCs) are required to tackle the increasing delay and poor scalability issues of bus-based communication architectures. Many of today's NoC designs are based on single path routing. By utilizing multiple paths for routing, congestion in the network is reduced significantly, which translates to improved network performance or reduced network bandwidth requirements and power consumption. Multiple paths can also be utilized to achieve spatial redundancy, which helps in achieving tolerance against faults or errors in the NoC. A major problem with multipath routing is that packets can reach the destination in an out-of-order fashion, while many applications require in-order packet delivery. In this work, we present a multipath routing strategy that guarantees in-order packet delivery for NoCs. It is based on the idea of routing packets on partially nonintersecting paths and rebuilding packet order at path reconvergent nodes. We present a design methodology that uses the routing strategy to optimally spread the traffic in the NoC to minimize the network bandwidth needs and power consumption. We also integrate support for tolerance against transient and permanent failures in the NoC links in the methodology by utilizing spatial and temporal redundancy for transporting packets. Our experimental studies show large reduction in network bandwidth requirements (36.86% on average) and power consumption (30.51% on average) compared to single-path systems. The area overhead of the proposed scheme is small (a modest 5% increase in network area). Hence, it is practical to be used in the on-chip domain.
Advanced Readout System IC Current Mode Semi-Gaussian Shapers Using CCIIs and OTAs
Authors: Noulis Thomas , Deradonis Constantinos , Siskos Stylianos
Published: April 2007

Novel CMOS current mode shapers for front-end electronics are proposed. In particular, six semi-Gaussian shaper implementations based on second generation current conveyors and operational transconductance amplifiers are designed using advanced filter design techniques. Although all shaper architectures are fully integrated, they satisfy a relatively large peaking time. The topologies are analytically compared in terms of noise performance, power consumption, total harmonic distortion (THD), and dynamic range (DR) in order to examine which is the most preferable in readout applications. Design technique selection criteria are proposed in relation to the shaper structures performance. Analysis is supported by simulations results using SPICE in a 0.6 μm process by Austria Mikro Systeme (AMS).
Selective Targeting and Potent Control of Tumor Growth Using an EphA2/CD3-Bispecific Single-Chain Antibody Construct
Authors: Hammond Scott A. , Lutterbuese Ralf , Roff Shannon , Lutterbuese Petra , Schlereth Bernd , Bruckheimer Elizabeth , Kinch Michael S. , Coats Steve , Baeuerle Patrick A. , Kufer Peter , Kiener Peter A.
Published: April 2007

The EphA2 receptor tyrosine kinase is frequently overexpressed and functionally altered in malignant cells and thus provides opportunities for selective targeting of tumor cells. We describe here the development of a novel, bispecific single-chain antibody (bscAb) referred to as bscEphA2xCD3. This molecule simultaneously targets EphA2 on tumor cells and the T-cell receptor/CD3 complex on T cells and possesses structural and functional characteristics of the recently developed BiTE technology. An EphA2-specific single-chain antibody was selected for recognition of an epitope that is preferentially exposed on malignant cells based on the concept of epitope exclusion; this was fused to a CD3-specific single-chain antibody to generate bscEphA2xCD3. The resultant bscAb redirected unstimulated human T cells to lyse EphA2-expressing tumor cells both in vitro and in vivo. In separate experiments, efficient tumor cell lysis was achieved in vitro at drug concentrations ≤1 μg/mL, at a low T-cell effector-to-tumor target cell ratio (1:1), and with tumor cells that possess few available binding sites (2,400 per cell) for bscEphA2xCD3. Time-lapsed microscopy revealed potent cytotoxic activity of bscEphA2xCD3-activated T cells against monolayers of malignant cells but not against monolayers of nontransformed EphA2-positive cells except at the edges of the monolayer where the target epitope was exposed. BscEphA2xCD3 was also efficacious in human xenograft mouse models modified to show human T-cell killing of tumors. Together, our results reveal opportunities for redirecting the potent activity of cytotoxic T cells towards tumor cells that express selectively accessible epitopes and establish EphA2-specific bscAb molecules as novel and potent therapeutics with selectivity for tumor cells. [Cancer Res 2007;67(8):3927–35]
Cancer Cell Lines as Genetic Models of Their Parent Histology: Analyses Based on Array Comparative Genomic Hybridization
Authors: Greshock Joel , Nathanson Katherine , Martin Anne-Marie , Zhang Lin , Coukos George , Weber Barbara L. , Zaks Tal Z.
Published: April 2007

Tumor-derived cell lines are used as in vitro cancer models, but their ability to accurately reflect the phenotype and genotype of the parental histology remains questionable, given the prevalence of documented cell line–specific cytogenetic changes. We have addressed the issue of whether copy number alterations seen in tumor-derived cell lines reflect those observed in studies of fresh tissue by carrying out a meta-analysis of array-based comparative genomic hybridization data that considers both copy number alteration frequencies and the occurrence of cancer gene amplifications and homozygous deletions. Pairwise correlation comparisons between the data sets of seven diagnosis-specific matched tumor and cell line groups indicate that the trends in aberration frequencies are highly correlated between tumors and cell line sets of matched cancer histology relative to unmatched pairings. Despite their similarities, cell lines showed uniformly higher locus-specific alteration frequencies (P = 0.004) and several recurring cell line–specific alterations emerged. These include the previously documented losses of 13q and 9p and gains of 20q, as well as additional undescribed cell line–specific gains of 5p, 7p, and 17q and losses of 18q and 4q. These results indicate that, on average, cell lines preserve in vitro the genetic aberrations that are unique to the parent histology from which they were derived while acquiring additional locus-specific alterations. These data may enable a more predictive understanding of individual cell lines as in vitro models of cancer biology and therapy. [Cancer Res 2007;67(8):3594–600]
Activatable Fluorescent Molecular Imaging of Peritoneal Metastases following Pretargeting with a Biotinylated Monoclonal Antibody
Authors: Hama Yukihiro , Urano Yasuteru , Koyama Yoshinori , Choyke Peter L. , Kobayashi Hisataka
Published: April 2007

Optical probes that yield high target-to-background ratios are necessary to detect microfoci of cancer that would otherwise escape detection with white light imaging. Target-specific activation of the optical signal at tumor foci is one mechanism by which high target and low background signal can be achieved. Here, we describe a two-step activation process in which the tumors are first pretargeted with a nonfluorescent biotinylated monoclonal antibody [cetuximab (Erbitux) targeting human epidermal growth factor receptor type 1 (HER1)]. Following this, a second agent, neutravidin-BODIPY-FL fluorescent conjugate, is given and binds to the previously targeted antibody, resulting in an ∼10-fold amplification of the optical fluorescence signal, leading to high tumor-to-background ratios. Spectral fluorescence imaging was done in a mouse model of peritoneal metastasis using a HER1-overexpressing cell line (A431) after pretargeting with biotinylated cetuximab and 3 h after administration of neutravidin-conjugated BODIPY-FL. Both aggregated tumors as well as small cancer implants were clearly visualized in vivo. For lesions ∼0.8 mm or greater in diameter, the spectral fluorescence imaging had a sensitivity of 96% (178 of 185) and a specificity of 98% (188 of 191). This two-step activation paradigm (pretargeting followed by neutravidin-biotin binding with an attached activatable fluorophore) could be useful in tumor-specific molecular imaging of various targets to guide surgical resections. [Cancer Res 2007;67(8):3809–17]
Anticancer Therapies Combining Antiangiogenic and Tumor Cell Cytotoxic Effects Reduce the Tumor Stem-Like Cell Fraction in Glioma Xenograft Tumors
Authors: Folkins Chris , Man Shan , Xu Ping , Shaked Yuval , Hicklin Daniel J. , Kerbel Robert S.
Published: April 2007

Vascular endothelial cells have been identified as a critical component of the neural stem cell niche, raising the possibility that brain tumor stem-like cells (TSLC) may also rely on signaling interactions with nearby tumor vasculature to maintain their stem-like state. The disruption of such a TSLC vascular niche by an antiangiogenic therapy could result in loss of stemness characteristics associated with intrinsic drug resistance and, thus, preferentially sensitize TSLC to the effects of chemotherapy. Considering these possibilities, we investigated the impact of antiangiogenic anticancer therapy on the TSLC fraction of glioma tumors. Athymic nude mice bearing s.c. tumor xenografts of the C6 rat glioma cell line were treated with either a targeted antiangiogenic agent, antiangiogenic schedules of low-dose metronomic chemotherapy, combination therapies of antiangiogenic agents and chemotherapy, or, for the purpose of comparison, a conventional cytotoxic schedule of maximum tolerated dose chemotherapy using cyclophosphamide. Targeted antiangiogenic therapy or cytotoxic chemotherapy did not reduce the fraction of tumor sphere-forming units (SFU) in the tumor, whereas all treatment groups that combined both antiangiogenic and cytotoxic drug effects caused a significant reduction in SFU. This work highlights the possibility that selective eradication of TSLC may be achieved by targeting the tumor microenvironment (and potentially a supportive TSLC niche) rather than the TSLC directly. Furthermore, this work suggests a possible novel effect of antiangiogenic therapy, namely, as a chemosensitizer of TSLC, and thus represents a possible new mechanism to explain the ability of antiangiogenic therapy to enhance the efficacy of chemotherapy. [Cancer Res 2007;67(8):3560–4]
Curcumin Potentiates Antitumor Activity of Gemcitabine in an Orthotopic Model of Pancreatic Cancer through Suppression of Proliferation, Angiogenesis, and Inhibition of Nuclear Factor-κB–Regulated Gene Products
Authors: Kunnumakkara Ajaikumar B. , Guha Sushovan , Krishnan Sunil , Diagaradjane Parmeswaran , Gelovani Juri , Aggarwal Bharat B.
Published: April 2007

Gemcitabine is currently the best treatment available for pancreatic cancer, but the disease develops resistance to the drug over time. Agents that can either enhance the effects of gemcitabine or overcome chemoresistance to the drug are needed for the treatment of pancreatic cancer. Curcumin, a component of turmeric (Curcuma longa), is one such agent that has been shown to suppress the transcription factor nuclear factor-κB (NF-κB), which is implicated in proliferation, survival, angiogenesis, and chemoresistance. In this study, we investigated whether curcumin can sensitize pancreatic cancer to gemcitabine in vitro and in vivo. In vitro, curcumin inhibited the proliferation of various pancreatic cancer cell lines, potentiated the apoptosis induced by gemcitabine, and inhibited constitutive NF-κB activation in the cells. In vivo, tumors from nude mice injected with pancreatic cancer cells and treated with a combination of curcumin and gemcitabine showed significant reductions in volume (P = 0.008 versus control; P = 0.036 versus gemcitabine alone), Ki-67 proliferation index (P = 0.030 versus control), NF-κB activation, and expression of NF-κB–regulated gene products (cyclin D1, c-myc, Bcl-2, Bcl-xL, cellular inhibitor of apoptosis protein-1, cyclooxygenase-2, matrix metalloproteinase, and vascular endothelial growth factor) compared with tumors from control mice treated with olive oil only. The combination treatment was also highly effective in suppressing angiogenesis as indicated by a decrease in CD31+ microvessel density (P = 0.018 versus control). Overall, our results suggest that curcumin potentiates the antitumor effects of gemcitabine in pancreatic cancer by suppressing proliferation, angiogenesis, NF-κB, and NF-κB–regulated gene products. [Cancer Res 2007;67(8):3853–61]
Cyclooxygenase-2 Transcription Is Regulated by Human Papillomavirus 16 E6 and E7 Oncoproteins: Evidence of a Corepressor/Coactivator Exchange
Authors: Subbaramaiah Kotha , Dannenberg Andrew J.
Published: April 2007

Cyclooxygenase (COX-2) is overexpressed in human papillomavirus (HPV)-induced diseases, including cervical cancer. Although HPV E6 and E7 oncoproteins have been causally linked to cervical carcinogenesis, their effects on COX-2 gene expression are unknown. Increased levels of COX-2 mRNA, protein, and prostaglandin E2 synthesis were detected in HPV16 E6- and E7-expressing cervical cancer cells (CaSki and SiHa) compared with an uninfected cervical cancer cell line (C33A). HPV16 E6 and E7 oncoproteins induced COX-2 transcription by activating the epidermal growth factor receptor (EGFR)→Ras→mitogen-activated protein kinase pathway. Interestingly, HPV16 oncoproteins stimulated EGFR signaling, in part, by inducing the release of amphiregulin, an EGFR ligand. The inductive effects of HPV16 E6 and E7 were mediated by enhanced binding of activator protein-1 to the cyclic AMP (cAMP)-responsive element (−59/−53) of the COX-2 promoter. The potential contribution of coactivators and corepressors to HPV16 E6- and E7-mediated induction of COX-2 was also investigated. Chromatin immunoprecipitation assays indicated that E6 and E7 oncoproteins induced the recruitment of phosphorylated c-Jun, c-Fos, UbcH5, and cAMP-responsive element binding protein–binding protein/p300 to the COX-2 promoter. In contrast, E6 and E7 inhibited the binding of the histone deacetylase 3-nuclear receptor corepressor (NCoR) complex to the COX-2 promoter. Moreover, overexpression of NCoR blocked E6- and E7-mediated stimulation of the COX-2 promoter. Taken together, these results indicate that HPV16 E6 and E7 oncoproteins stimulated COX-2 transcription by inducing a corepressor/coactivator exchange. To our knowledge, this study also provides the first evidence that NCoR can function as a repressor of COX-2 gene expression. [Cancer Res 2007;67(8):3976–85]
A Selective Small Molecule Inhibitor of c-Met, PHA665752, Inhibits Tumorigenicity and Angiogenesis in Mouse Lung Cancer Xenografts
Authors: Puri Neelu , Khramtsov Andrey , Ahmed Salman , Nallasura Vidya , Hetzel Jeremy T. , Jagadeeswaran Ramasamy , Karczmar Greg , Salgia Ravi
Published: April 2007

The c-Met receptor tyrosine kinase is emerging as a novel target in many solid tumors, including lung cancer. PHA-665752 was identified as a small molecule, ATP competitive inhibitor of the catalytic activity of the c-Met kinase. Here, we show that treatment with PHA665752 reduced NCI-H69 (small cell lung cancer) and NCI-H441 (non–small cell lung cancer) tumorigenicity in mouse xenografts by 99% and 75%, respectively. Reduction in tumor size was also observed by magnetic resonance imaging of tumors in mice. PHA665752 inhibited c-Met phosphorylation at the autophosphorylation and c-Cbl binding sites in mouse xenografts derived from non–small cell lung cancer cell lines (NCI-H441 and A549) and small cell lung cancer cell line (NCI-H69). PHA665752 also inhibited angiogenesis by >85% in all the abovementioned cell lines and caused an angiogenic switch which resulted in a decreased production of vascular endothelial growth factor and an increase in the production of the angiogenesis inhibitor thrombospondin-1. These studies show the feasibility of selectively targeting c-Met with ATP competitive small molecule inhibitors and suggest that PHA665752 may provide a novel therapeutic approach to lung cancer. [Cancer Res 2007;67(8):3529–34]
A Variant in the Cytochrome P450 Oxidoreductase Gene Is Associated with Breast Cancer Risk in African Americans
Authors: Haiman Christopher A. , Setiawan V. Wendy , Xia Lucy Y. , Le Marchand Loïc , Ingles Sue A. , Ursin Giske , Press Michael F. , Bernstein Leslie , John Esther M. , Henderson Brian E.
Published: April 2007

Variation in the cytochrome P450 oxidoreductase (POR) gene, a key regulator of type II cytochrome P450 enzymes, may affect exposure to endogenous steroid hormones and breast cancer risk. We sequenced the POR locus and tested candidate polymorphisms G5G and A503V for association with breast cancer risk among women in the Multiethnic Cohort Study (1,615 cases and 1,962 controls). The single nucleotide polymorphism (SNP) A503V was common in all racial/ethnic populations (minor allele frequency, ≥0.05) but was not associated with risk. SNP G5G (A → G nucleotide change), which lies in a suggestive exonic splicing enhancer motif in exon 1, was common only in African Americans (minor allele frequency, 0.21) and the homozygous state was modestly associated with increased breast risk among all cases [345 cases and 426 controls; odds ratio (OR), 1.64; 95% confidence interval (CI), 0.89–3.04; P = 0.12] and among cases with advanced disease (95 cases: OR, 3.08; 95% CI, 1.42–6.70; P = 0.005). In an attempt to replicate this association, we genotyped SNP G5G in additional African American case-control studies (747 cases and 468 controls). Nonsignificant positive associations were noted with the GG genotype class in all studies. In the pooled analysis (1,038 cases and 877 controls with genotype data), the association was statistically significant among all cases (OR, 1.58; 95% CI, 1.04–2.41; P = 0.03) and stronger in those with advanced disease (411 cases and 877 controls; OR, 2.60; 95% CI, 1.56–4.34; P = 0.0002). These data suggest that African Americans harbor an allele at the POR locus that may increase breast cancer risk. [Cancer Res 2007;67(8):3565–8]
Novel Somatic and Germline Mutations in Cancer Candidate Genes in Glioblastoma, Melanoma, and Pancreatic Carcinoma
Authors: Balakrishnan Asha , Bleeker Fonnet E. , Lamba Simona , Rodolfo Monica , Daniotti Maria , Scarpa Aldo , van Tilborg Angela A. , Leenstra Sieger , Zanon Carlo , Bardelli Alberto
Published: April 2007

A recent systematic sequence analysis of well-annotated human protein coding genes or consensus coding sequences led to the identification of 189 genes displaying somatic mutations in breast and colorectal cancers. Based on their mutation prevalence, a subset of these genes was identified as cancer candidate (CAN) genes as they could be potentially involved in cancer. We evaluated the mutational profiles of 19 CAN genes in the highly aggressive tumors: glioblastoma, melanoma, and pancreatic carcinoma. Among other changes, we found novel somatic mutations in EPHA3, MLL3, TECTA, FBXW7, and OBSCN, affecting amino acids not previously found to be mutated in human cancers. Interestingly, we also found a germline nucleotide variant of OBSCN that was previously reported as a somatic mutation. Our results identify specific genetic lesions in glioblastoma, melanoma, and pancreatic cancers and indicate that CAN genes and their mutational profiles are tumor specific. Some of the mutated genes, such as the tyrosine kinase EPHA3, are clearly amenable to pharmacologic intervention and could represent novel therapeutic targets for these incurable cancers. We also speculate that similar to other oncogenes and tumor suppressor genes, mutations affecting OBSCN could be involved in cancer predisposition. [Cancer Res 2007;67(8):3545–50]
Phenethyl Isothiocyanate, a Cancer Chemopreventive Constituent of Cruciferous Vegetables, Inhibits Cap-Dependent Translation by Regulating the Level and Phosphorylation of 4E-BP1
Authors: Hu Jing , Straub Jonathan , Xiao Dong , Singh Shivendra V. , Yang Hsin-Sheng , Sonenberg Nahum , Vatsyayan Jaya
Published: April 2007

Phenethyl isothiocyanate (PEITC), a constituent of many edible cruciferous vegetables, exerts significant protection against chemically induced cancer in animal models and inhibits growth of cancer cells in culture and in vivo by causing cell cycle arrest and apoptosis induction. In this study, we report a novel response to PEITC involving the regulation of translation initiation at pharmacologically achievable concentrations. Treatment of human colorectal cancer HCT-116 cells and human prostate cancer PC-3 cells, but not a normal prostate epithelial cell line (PrEC), with PEITC caused an increase in expression of the eukaryotic translation initiation factor 4E (eIF4E) binding protein (4E-BP1) and inhibition of 4E-BP1 phosphorylation. Results from pull-down assay using 7-methyl-GTP Sepharose 4B beads indicated that PEITC treatment reduced cap-bound eIF4E, confirming that increased 4E-BP1 expression and inhibition of 4E-BP1 phosphorylation indeed reduced the availability of eIF4E for translation initiation. Accordingly, results from in vivo translation using luciferase reporter assay indicated that PEITC treatment inhibited cap-dependent translation, in particular the translation of mRNA with secondary structure (stem-loop structure). Ectopic expression of eIF4E prevented PEITC-induced translation inhibition and conferred significant protection against PEITC-induced apoptosis. These results indicate that PEITC modulates availability of eIF4E for translation initiation leading to inhibition of cap-dependent translation. The present study also suggests that inhibition of cap-dependent translation may be an important mechanism in PEITC-induced apoptosis. [Cancer Res 2007;67(8):3569–73]
Catecholamine Release–Inhibitory Peptide Catestatin (Chromogranin A
352–372
)
Authors: Rao Fangwen , Wen Gen , Gayen Jiaur R. , Das Madhusudan , Vaingankar Sucheta M. , Rana Brinda K. , Mahata Manjula , Kennedy Brian P. , Salem Rany M. , Stridsberg Mats , Abel Kenneth , Smith Douglas W. , Eskin Eleazar , Schork Nicholas J. , Hamilton Bruce A. , Ziegler Michael G. , Mahata Sushil K. , O’Connor Daniel T.
Published: April 2007

Background—

Chromogranin A, coreleased with catecholamines by exocytosis, is cleaved to the catecholamine release–inhibitory fragment catestatin. We identified a natural nonsynonymous variant of catestatin, Gly364Ser, that alters human autonomic function and blood pressure.

Methods and Results—

Gly364Ser heterozygotes and controls underwent physiological and biochemical phenotyping, including catecholamine production, chromogranin A precursor, and its catestatin product. Case-control studies replicated effects of the gene on blood pressure in the population. Gly364Ser displayed diminished inhibition of catecholamine secretion from cultured neurons. Gly/Ser heterozygotes displayed increased baroreceptor slope during upward deflections (by ≈47%) and downward deflections (by ≈44%), increased cardiac parasympathetic index (by ≈2.4-fold), and decreased cardiac sympathetic index (by ≈26%). Renal norepinephrine excretion was diminished by ≈26% and epinephrine excretion by ≈34% in Gly/Ser heterozygotes. The coalescent dated emergence of the variant to ≈70 000 years ago. Gly364Ser was in linkage disequilibrium with 1 major
Chromogranin A
promoter haplotype, although promoter haplotypes did not predict autonomic phenotypes. The 364Ser variant was associated with lower diastolic blood pressure in 2 independent/confirmatory groups of patients with hypertension; genotype groups differed by ≈5 to 6 mm Hg, and the polymorphism accounted for ≈1.8% of population diastolic blood pressure variance, although a significant gene-by-sex interaction existed, with an enhanced effect in men.

Conclusions—

The catestatin Gly364Ser variant causes profound changes in human autonomic activity, both parasympathetic and sympathetic, and seems to reduce risk of developing hypertension, especially in men. A model for catestatin action in the baroreceptor center of the nucleus of the tractus solitarius accounts for these actions.
Targeting Platelets in Acute Experimental Stroke
Authors: Kleinschnitz Christoph , Pozgajova Miroslava , Pham Mirko , Bendszus Martin , Nieswandt Bernhard , Stoll Guido
Published: April 2007

Background—

Ischemic stroke is a frequent and serious disease with limited treatment options. Platelets can adhere to hypoxic cerebral endothelial cells by binding of their glycoprotein (GP) Ib receptor to von Willebrand factor. Exposure of subendothelial matrix proteins further facilitates firm attachment of platelets to the vessel wall by binding of collagen to their GPVI receptor. In the present study, we addressed the pathogenic role of GPIb, GPVI, and the aggregation receptor GPIIb/IIIa in experimental stroke in mice.

Methods and Results—

Complete blockade of GPIbα was achieved by intravenous injection of 100 μg Fab fragments of the monoclonal antibody p0p/B to mice undergoing 1 hour of transient middle cerebral artery occlusion. At 24 hours after transient middle cerebral artery occlusion, cerebral infarct volumes were assessed by 2,3,5-triphenyltetrazolium chloride staining. In mice treated with anti-GPIbα Fab 1 hour before middle cerebral artery occlusion, ischemic lesions were reduced to ≈40% compared with controls (28.5±12.7 versus 73.9±17.4 mm
3
, respectively;
P
<0.001). Application of anti-GPIbα Fab 1 hour after middle cerebral artery occlusion likewise reduced brain infarct volumes (24.5±7.7 mm
3
;
P
<0.001) and improved the neurological status. Similarly, depletion of GPVI significantly diminished the infarct volume but to a lesser extent (49.4±19.1 mm
3
;
P
<0.05). Importantly, the disruption of early steps of platelet activation was not accompanied by an increase in bleeding complications as revealed by serial magnetic resonance imaging. In contrast, blockade of the final common pathway of platelet aggregation with anti-GPIIb/IIIa F(ab)
2
fragments had no positive effect on stroke size and functional outcome but increased the incidence of intracerebral hemorrhage and mortality after transient middle cerebral artery occlusion in a dose-dependent manner.

Conclusions—

Our data indicate that the selective blockade of key signaling pathways of platelet adhesion and aggregation has a different impact on stroke outcome and bleeding complications. Inhibition of early steps of platelet adhesion to the ischemic endothelium and the subendothelial matrix may offer a novel and safe treatment strategy in acute stroke.