bluuebunny/crossref_metadata_2025_split huggingface dataset:
In Vitro Human Immunodeficiency Virus Type 1 Resistance Selections with Combinations of Tenofovir and Emtricitabine or Abacavir and Lamivudine
Authors: Margot N. A. , Waters J. M. , Miller M. D. 
Published: November 2006

ABSTRACTHuman immunodeficiency virus type 1 (HIV-1) resistance development was evaluated in vitro by using combinations of the drugs tenofovir and emtricitabine or abacavir and lamivudine, as well as by using the compounds individually. Emtricitabine- and lamivudine-resistant HIV-1 isolates with the M184I or M184V mutation in reverse transcriptase were readily selected in the cultures with emtricitabine alone, lamivudine alone, and the two drug combinations and conferred high-level resistance to emtricitabine and lamivudine. Tenofovir-resistant HIV-1 isolates with the K65R mutation occurred in both the culture with tenofovir alone and the culture with the combination of emtricitabine and tenofovir. The S68N and S68K mutations were also observed in the tenofovir cultures, with no detectable impact on resistance, suggesting a possible compensatory role in viral fitness. At low concentrations of emtricitabine and tenofovir, the M184I mutation appeared first, followed by the K65R mutation, in a subset of viruses. At intermediate concentrations of emtricitabine and tenofovir, viruses harboring the K65R mutation or a novel K65N and K70R double mutation grew before they gave rise to mutants with K65R and M184V/I double mutations at higher emtricitabine concentrations. Abacavir resistance was characterized by the accumulation of the M184V, Y115F, and K65R mutations in the abacavir culture, while the M184V and L74V mutations were selected in combination with lamivudine. In the presence of the abacavir resistance mutations, viral growth was strong even in the presence of high concentrations of abacavir. In contrast, viral growth was markedly impaired in the cultures with high tenofovir concentrations, even in the presence of K65R. In conclusion, these studies show that HIV-1 mutants with a K65R and M184V genotype are generated under maximum selection pressure from the combination of tenofovir and emtricitabine.
Oxidant Generation by Single Infected Monocytes after Short-Term Fluorescence Labeling of a Protozoan Parasite
Authors: Chang Haeok K. , Thalhofer Colin , Duerkop Breck A. , Mehling Joanna S. , Verma Shilpi , Gollob Kenneth J. , Almeida Roque , Wilson Mary E. 
Published: November 2006

ABSTRACTLeishmaniaspp. are intracellular protozoa residing in mononuclear phagocytes.Leishmaniaorganisms are susceptible to microbicidal responses generated in response to phagocytosis. Assuming that both phagocyte and parasite populations are heterogeneous, it is advantageous to examine the response of individual cells phagocytosing living parasites. BecauseLeishmaniaspp. lose virulence during the raising of transfectants, we developed a method to label liveLeishmania chagasishort-term with fluorescent dyes. Up to six parasite divisions were detected by flow cytometry after labeling with carboxyfluorescein diacetate succinimidyl ester (CFSE), dioctadecyl-tetramethylindo carbocyanine perchlorate, or chloromethyl tetramethylrhodamine. Labeled parasites entered mononuclear phagocytes as determined by confocal and time-lapse microscopy. Dihydroethidium (DHE) was used to detect macrophage-derived oxidants generated during phagocytosis. PresumablyLeishmaniaorganisms are opsonized with host serum/tissue components such as complement prior to phagocytosis. Therefore, we investigated the effects of opsonization and found that this increased the efficiency of CFSE-labeled parasite entry into monocytes (84.6% ± 8.8% versus 20.2% ± 3.8% monocytes infected;P< 0.001). Opsonization also increased the percentage of phagocytes undergoing a respiratory burst (66.0% ± 6.3% versus 41.0% ± 8.3% of monocytes containing CFSE-labeled parasites;P< 0.001) and the magnitude of oxidant generation by each infected monocyte. Inhibitor data indicated that DHE was oxidized by products of the NADPH oxidase. These data suggest that opsonized serum components such as complement lead to more efficient entry ofLeishmaniainto their target cells but at the same time activate the phagocyte oxidase to generate microbicidal products in infected cells. The parasite must balance these positive and negative survival effects in order to initiate a viable infection.
Mutants of Type II Heat-Labile Enterotoxin LT-IIa with Altered Ganglioside-Binding Activities and Diminished Toxicity Are Potent Mucosal Adjuvants
Authors: Nawar Hesham F. , Arce Sergio , Russell Michael W. , Connell Terry D. 
Published: November 2006

ABSTRACTThe structure and function LT-IIa, a type II heat-labile enterotoxin ofEscherichia coli, are closely related to the structures and functions of cholera toxin and LT-I, the type I heat-labile enterotoxins ofVibrio choleraeand enterotoxigenicEscherichia coli, respectively. While LT-IIa is a potent systemic and mucosal adjuvant, recent studies demonstrated that mutant LT-IIa(T34I), which exhibits no detectable binding activity as determined by an enzyme-linked immunosorbent assay, with gangliosides GD1b, GD1a, and GM1 is a very poor adjuvant. To evaluate whether other mutant LT-IIa enterotoxins that also exhibit diminished ganglioside-binding activities have greater adjuvant activities, BALB/c mice were immunized by the intranasal route with the surface adhesin protein AgI/II ofStreptococcus mutansalone or in combination with LT-IIa, LT-IIa(T14S), LT-IIa(T14I), or LT-IIa(T14D). All three mutant enterotoxins potentiated strong mucosal immune responses that were equivalent to the response promulgated by wt LT-IIa. All three mutant enterotoxins augmented the systemic immune responses that correlated with their ganglioside-binding activities. Only LT-IIa and LT-IIa(T14S), however, enhanced expression of major histocompatibility complex class II and the costimulatory molecules CD40, CD80, and CD86 on splenic dendritic cells. LT-IIa(T14I) and LT-IIa(T14D) had extremely diminished toxicities in a mouse Y1 adrenal cell bioassay and reduced abilities to induce the accumulation of intracellular cyclic AMP in a macrophage cell line.
Enteropathogenic
Escherichia coli
,
Shigella flexneri
, and
Listeria monocytogenes
Recruit a Junctional Protein, Zonula Occludens-1, to Actin Tails and Pedestals
Authors: Hanajima-Ozawa Miyuki , Matsuzawa Takeshi , Fukui Aya , Kamitani Shigeki , Ohnishi Hiroe , Abe Akio , Horiguchi Yasuhiko , Miyake Masami 
Published: November 2006

ABSTRACT

Enteropathogenic
Escherichia coli
,
Shigella flexneri
, and
Listeria monocytogenes
induce localized actin polymerization at the cytoplasmic face of the plasma membrane or within the host cytoplasm, creating unique actin-rich structures termed pedestals or actin tails. The process is known to be mediated by the actin-related protein 2 and 3 (Arp2/3) complex, which in these cases acts downstream of neural Wiskott-Aldrich syndrome protein (N-WASP) or of a listerial functional homolog of WASP family proteins. Here, we show that zonula occludens-1 (ZO-1), a protein in the tight junctions of polarized epithelial cells, is recruited to actin tails and pedestals. Immunocytochemical analysis revealed that ZO-1 was stained most in the distal part of the actin-rich structures, and the incorporation was mediated by the proline-rich region of the ZO-1 molecule. The direct clustering of membrane-targeted Nck, which is known to activate the N-WASP-Arp2/3 pathway, triggered the formation of the ZO-1-associated actin tails. The results suggest that the activation of the Arp2/3 complex downstream of N-WASP or a WASP-related molecule is a key to the formation of the particular actin-rich structures that bind with ZO-1. We propose that an analysis of the recruitment on a molecular basis will lead to an understanding of how ZO-1 recognizes a distinctive actin-rich structure under pathophysiological conditions.
Vaccination with Live
Yersinia pestis
Primes CD4 and CD8 T Cells That Synergistically Protect against Lethal Pulmonary
Y. pestis
Infection
Authors: Philipovskiy Alexander V. , Smiley Stephen T. 
Published: November 2006

ABSTRACT

Vaccination with live attenuated
Yersinia pestis
confers protection against pneumonic plague but is not considered safe for general use. Subunit plague vaccines containing the
Y. pestis
F1 and LcrV proteins prime robust antibody responses but may not provide sufficient protection. To aid the development of a safe and effective plague vaccine, we are investigating roles for T cells during defense against
Y. pestis
infection. Here we demonstrate that vaccination of mice with live
Y. pestis
primes specific CD4 and CD8 T cells that, upon purification and direct transfer to naïve mice, synergistically protect against lethal intranasal
Y. pestis
challenge. While not preventing extrapulmonary dissemination, the coadministered T cells promote bacterial clearance and reduce bacteremia. These observations strongly suggest that development of pneumonic plague vaccines should strive to prime both CD4 and CD8 T cells. Finally, we demonstrate that vaccination with live
Y. pestis
primes CD4 and CD8 T cells that respond to
Y. pestis
strains lacking the capacity to express F1, LcrV, and all pCD1/pPCP-encoded proteins, suggesting that protective T cells likely recognize antigens distinct from those previously defined as targets for humoral immunity.
Mapping Geographic Zones of Cancer Risk with Epigenetic Biomarkers in Normal Breast Tissue
Authors: Yan Pearlly S. , Venkataramu Chinnambally , Ibrahim Ashraf , Liu Joseph C. , Shen Rulong Z. , Diaz Nils M. , Centeno Barbara , Weber Frank , Leu Yu-Wei , Shapiro Charles L. , Eng Charis , Yeatman Timothy J. , Huang Tim H.-M. 
Published: November 2006

AbstractPurpose: Genetic alterations were previously identified in normal epithelia adjacent to invasive cancers. The aim of this study was to determine DNA methylation in histologically normal tissues from multiple geographic zones adjacent to primary breast tumors.Experimental Design: First, methylation status of a 4-kb region of RASSF1A promoter was interrogated using oligonucleotide-based microarray in 144 samples (primary tumors, 47; adjacent normals, 69; reduction mammoplasty tissues, 28). Second, allelic imbalance (AI)/loss of heterozygosity (LOH) surrounding RASSF1A promoter were analyzed in 30 samples (tumors, 8; adjacent normals, 22). Third, global methylation screening of 49 samples (tumors, 12; adjacent normals, 25; reduction mammoplasty, 12) was done by differential methylation hybridization. Real-time quantitative methylation-specific PCR was used to validate the microarray findings.Results: DNA methylation in the core RASSF1A promoter was low in reduction mammoplasty tissues (P = 0.0001) when compared with primary tumors. The adjacent normals had an intermediate level of methylation. The regions surrounding the core were highly methylated in all sample types. Microsatellite markers showed AI/LOH in tumors and some of the adjacent normals. Concurrent AI/LOH and DNA methylation in RASSF1A promoter occurred in two of six tumors. Global methylation screening uncovered genes more methylated in adjacent normals than in reduction mammoplasty tissues. The methylation status of four genes was confirmed by quantitative methylation-specific PCR.Conclusions: Our findings suggest a field of methylation changes extending as far as 4 cm from primary tumors. These frequent alterations may explain why normal tissues are at risk for local recurrence and are useful in disease prognostication.
Axillary Lymph Node Nanometastases Are Prognostic Factors for Disease-Free Survival and Metastatic Relapse in Breast Cancer Patients
Authors: Querzoli Patrizia , Pedriali Massimo , Rinaldi Rosa , Lombardi Anna Rita , Biganzoli Elia , Boracchi Patrizia , Ferretti Stefano , Frasson Claudia , Zanella Caterina , Ghisellini Sara , Ambrogi Federico , Antolini Laura , Piantelli Mauro , Iacobelli Stefano , Marubini Ettore , Alberti Saverio , Nenci Italo 
Published: November 2006

Abstract
Purpose: Early breast cancer presents with a remarkable heterogeneity of outcomes. Undetected, microscopic lymph node tumor deposits may account for a significant fraction of this prognostic diversity. Thus, we systematically evaluated the presence of lymph node tumor cell deposits ≤0.2 mm in diameter [pN0(i+), nanometastases] and analyzed their prognostic effect.
Experimental Design: Single-institution, consecutive patients with 8 years of median follow-up (n = 702) were studied. To maximize chances of detecting micrometastases and nanometastases, whole-axilla dissections were analyzed. pN0 cases (n = 377) were systematically reevaluated by lymph node (n = 6676) step-sectioning and anticytokeratin immunohistochemical analysis. The risk of first adverse events and of distant relapse of bona fide pN0 patients was compared with that of pN0(i+), pN1mi, and pN1 cases.
Results: Minimal lymph node deposits were revealed in 13% of pN0 patients. The hazard ratio for all adverse events of pN0(i+) versus pN0(i−) was 2.51 (P = 0.00019). Hazards of pN1mi and pN0(i+) cases were not significantly different. A multivariate Cox model showed a hazard ratio of 2.16 for grouped pN0(i+)/pN1mi versus pN0(i−) (P = 0.0005). Crude cumulative incidence curves for metastatic relapse were also significantly different (Gray's test χ2 = 5.54, P = 0.019).
Conclusion: Nanometastases are a strong risk factor for disease-free survival and for metastatic relapse. These findings support the inclusion of procedures for nanometastasis detection in tumor-node-metastasis staging.
FGFR1 Emerges as a Potential Therapeutic Target for Lobular Breast Carcinomas
Authors: Reis-Filho Jorge Sergio , Simpson Pete T. , Turner Nicholas C. , Lambros Maryou Ballo , Jones Chris , Mackay Alan , Grigoriadis Anita , Sarrio David , Savage Kay , Dexter Tim , Iravani Marjan , Fenwick Kerry , Weber Barbara , Hardisson David , Schmitt Fernando Carlos , Palacios Jose , Lakhani Sunil R. , Ashworth Alan 
Published: November 2006

Abstract
Purpose: Classic lobular carcinomas (CLC) account for 10% to 15% of all breast cancers. At the genetic level, CLCs show recurrent physical loss of chromosome16q coupled with the lack of E-cadherin (CDH1 gene) expression. However, little is known about the putative therapeutic targets for these tumors. The aim of this study was to characterize CLCs at the molecular genetic level and identify putative therapeutic targets.
Experimental Design: We subjected 13 cases of CLC to a comprehensive molecular analysis including immunohistochemistry for E-cadherin, estrogen and progesterone receptors, HER2/neu and p53; high-resolution comparative genomic hybridization (HR-CGH); microarray-based CGH (aCGH); and fluorescent and chromogenic in situ hybridization for CCND1 and FGFR1.
Results: All cases lacked the expression of E-cadherin, p53, and HER2, and all but one case was positive for estrogen receptors. HR-CGH revealed recurrent gains on 1q and losses on 16q (both, 85%). aCGH showed a good agreement with but higher resolution and sensitivity than HR-CGH. Recurrent, high level gains at 11q13 (CCND1) and 8p12-p11.2 were identified in seven and six cases, respectively, and were validated with in situ hybridization. Examination of aCGH and the gene expression profile data of the cell lines, MDA-MB-134 and ZR-75-1, which harbor distinct gains of 8p12-p11.2, identified FGFR1 as a putative amplicon driver of 8p12-p11.2 amplification in MDA-MB-134. Inhibition of FGFR1 expression using small interfering RNA or a small-molecule chemical inhibitor showed that FGFR1 signaling contributes to the survival of MDA-MB-134 cells.
Conclusions: Our findings suggest that receptor FGFR1 inhibitors may be useful as therapeutics in a subset of CLCs.
Fluorescence Visualization Detection of Field Alterations in Tumor Margins of Oral Cancer Patients
Authors: Poh Catherine F. , Zhang Lewei , Anderson Don W. , Durham J. Scott , Williams P. Michele , Priddy Robert W. , Berean Ken W. , Ng Samson , Tseng Olivia L. , MacAulay Calum , Rosin Miriam P. 
Published: November 2006

AbstractPurpose: Genetically altered cells could become widespread across the epithelium of patients with oral cancer, often in clinically and histologically normal tissue, and contribute to recurrent disease. Molecular approaches have begun to yield information on cancer/risk fields; tissue optics could further extend our understanding of alteration to phenotype as a result of molecular change.Experimental Design: We used a simple hand-held device in the operating room to directly visualize subclinical field changes around oral cancers, documenting alteration to fluorescence. A total of 122 oral mucosa biopsies were obtained from 20 surgical specimens with each biopsy being assessed for location, fluorescence visualization (FV) status, histology, and loss of heterozygosity (LOH; 10 markers on three regions: 3p14, 9p21, and 17p13).Results: All tumors showed FV loss (FVL). For 19 of the 20 tumors, the loss extended in at least one direction beyond the clinically visible tumor, with the extension varying from 4 to 25 mm. Thirty-two of 36 FVL biopsies showed histologic change (including 7 squamous cell carcinoma/carcinomas in situ, 10 severe dysplasias, and 15 mild/moderate dysplasias) compared with 1 of the 66 FV retained (FVR) biopsies. Molecular analysis on margins with low-grade or no dysplasia showed a significant association of LOH in FVL biopsies, with LOH at 3p and/or 9p (previously associated with local tumor recurrence) present in 12 of 19 FVL biopsies compared with 3 of 13 FVR biopsies (P = 0.04).Conclusions: These data have, for the first time, shown that direct FV can identify subclinical high-risk fields with cancerous and precancerous changes in the operating room setting.
Synopsis of a Roundtable on Validating Novel Therapeutics for Multiple Myeloma
Authors: Dalton William , Anderson Kenneth C. 
Published: November 2006

Abstract
Purpose: With the identification of new molecular targets and pathways, many new therapeutic approaches are being identified for potential application in the treatment of multiple myeloma. New chemical compounds and biologics have been developed against molecular targets with substantial scientific evidence that these targets are involved in myeloma development, progression, or relapse. To safely and rapidly bring these advances to bear on the disease, new preclinical models in cells and animals need to be established, as well as prioritization and standardization in current preclinical and clinical validation. An experts' roundtable was convened in November 2005 to discuss shortcomings in current preclinical models and discuss what models are needed to best validate therapeutics and combinations of therapies for multiple myeloma.
Conclusions: This exciting event brought together experts in compound validation, preclinical development, and experts in multiple myeloma from academic institutions and the pharmaceutical and biotechnology industries. The goals were to evaluate an algorithm for therapeutic validation and discuss in vitro modeling for target discovery, animal models for preclinical development, and models for testing drug combinations.
Molecular and Cytogenetic Subgroups of Oropharyngeal Squamous Cell Carcinoma
Authors: Perrone Federica , Suardi Simona , Pastore Elisa , Casieri Paola , Orsenigo Marta , Caramuta Stefano , Dagrada Gianpaolo , Losa Marco , Licitra Lisa , Bossi Paolo , Staurengo Samantha , Oggionni Maria , Locati Laura , Cantu Giulio , Squadrelli Massimo , Carbone Antonino , Pierotti Marco A. , Pilotti Silvana 
Published: November 2006

Abstract
Purpose: The aim of this study was to acquire further insights into the pathogenetic pathways of head and neck squamous cell carcinomas (HNSCC) that may be useful for identifying new biomarkers instrumental in developing more specific treatment approaches.
Experimental Design: Cell cycle regulators and epidermal growth factor receptor (EGFR) and BRAF genes were analyzed in a series of 90 oropharyngeal SCCs of a cohort of surgically treated patients from a single institution, and the results were matched with the presence of high-risk human papillomavirus (HR-HPV) DNA and the TP53 status.
Results: At least four distinct groups of tumors were identified sharing a common histology but displaying different molecular/cytogenetic patterns: (a) 19% were HPV-positive SCCs whose lack of alterations of the investigated genes could explain their particular natural history, which requires less aggressive treatment; (b) 37% were HPV-negative SCCs carrying TP53 mutations, which may be more effectively treated by drugs acting through p53-independent apoptosis; (c) 34% were HPV-negative SCCs carrying wild-type TP53 and loss of 9p21 (p16INK4a and p15INK4b) and/or cyclin D1 overexpression that justify treatment with DNA-damaging drugs followed by cell cycle inhibitors; and (d) 10% were HPV-negative lacking tumor suppressor genes and cell cycle alterations. The second, third, and fourth groups also showed an increased copy number of EGFR and chromosome 7 (43%) that might justify the additional or alternative use of EGFR inhibitors.
Conclusions: Our findings suggest that assessing HPV, TP53, 9p21, and EGFR status may be crucial to finding more tailored and beneficial treatments for oropharyngeal SCCs.
Targeting the active β-catenin pathway to treat cancer cells
Authors: Dvory-Sobol Hadas , Sagiv Eyal , Kazanov Diana , Ben-Ze'ev Avri , Arber Nadir 
Published: November 2006

Abstract
The adenomatous polyposis coli or β-catenin genes are frequently mutated in colorectal cancer cells, resulting in oncogenic activation of β-catenin signaling. We tried to establish in vitro and in vivo models for selectively killing human cancer cells with an activated β-catenin/T-cell factor (Tcf) pathway. We used a recombinant adenovirus that carries a lethal gene [p53-up-regulated modulator of apoptosis (PUMA)] under the control of a β-catenin/Tcf–responsive promoter (AdTOP-PUMA) to selectively target human colorectal cancer cells (SW480, HCT116, DLD-1, and LS174T), hepatocellular carcinoma (HepG2), and gastric cancer cells (AGS) in which the β-catenin/Tcf pathway is activated, and compared its efficiency in killing cancer cells in which this pathway is inactive or only weakly active. AdFOP-PUMA, carrying a mutant Tcf-binding site, was used as control virus. The combined effect of AdTOP-PUMA with several chemotherapeutic agents (5-florouracil, doxorubicin, and paclitaxel) was also evaluated. The effect of AdTOP-PUMA on colorectal cancer cells was also examined in nude mice: SW480 cells were infected with the AdTOP-PUMA and AdFOP-PUMA, and then inoculated s.c. into nude mice. The TOP-PUMA adenovirus inhibited cell growth in a dose-dependent fashion, depending on the signaling activity of β-catenin. The growth of cells displaying high levels of active β-catenin/Tcf signaling was inhibited after infection with AdTOP-PUMA, whereas that of cells with low levels of β-catenin signaling was not. Growth inhibition was associated with induction of apoptosis. Chemotherapy synergistically enhanced the effect of AdTOP-PUMA. A combination of the adenovirus system with standard therapy may improve the efficacy and reduce the toxicity of therapy in humans. [Mol Cancer Ther 2006;5(11):2861–71]