bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inhibition by Woodchuck Hepatitis Virus of Class I Major Histocompatibility Complex Presentation on Hepatocytes Is Mediated by Virus Envelope Pre-S2 Protein and Can Be Reversed by Treatment with Gamma Interferon
Authors: Wang Jinguo , Michalak Tomasz I. 
Published: August 2006

ABSTRACT

Presentation of class I major histocompatibility complex (MHC) is severely down-regulated on hepatocytes in chronic hepatitis caused by woodchuck hepatitis virus (WHV). To determine which of the viral proteins mediates class I MHC antigen suppression, cultured normal woodchuck hepatocytes were transfected with the complete WHV genome, sequences encoding individual virus proteins, or whole virus genomes in which transcription of selected proteins was disabled by site-specific mutagenesis. It was found that hepatocyte presentation of class I MHC antigen was significantly inhibited following transfection with complete WHV genome or with viral subgenomic fragments encoding envelope pre-S2 protein or pre-S1 protein, which naturally encompasses pre-S2 amino acid sequence. In contrast, hepatocytes transfected with WHV X gene alone demonstrated a profound enhancement in the class I antigen display, whereas those expressing virus major S protein or nucleocapsid (core) protein were not different from control hepatocytes. Analysis of the mutated WHV sequences confirmed that the envelope pre-S2 protein was responsible for inhibition of the class I MHC antigen display. Interestingly, treatment with recombinant woodchuck gamma interferon (rwIFN-γ) restored the inhibited presentation of the class I antigen. Moreover, the class I antigen suppression was not associated with down-regulation of hepatocyte genes for class I MHC heavy chain, β
2
-microglobulin, transporters associated with antigen processing, and proteasome subunits. These findings indicate that the defective presentation of class I MHC antigen on hepatocytes transcribing WHV is a consequence of posttranscriptional suppression exerted by virus pre-S2 protein and that this hindrance can be fully reversed by IFN-γ.
Functional Entry of Baculovirus into Insect and Mammalian Cells Is Dependent on Clathrin-Mediated Endocytosis
Authors: Long Gang , Pan Xiaoyu , Kormelink Richard , Vlak Just M. 
Published: August 2006

ABSTRACT
Entry of the budded virus form of baculoviruses into insect and mammalian cells is generally thought to occur through a low-pH-dependent endocytosis pathway, possibly through clathrin-coated pits. This insight is primarily based on (immuno)electron microscopy studies but requires biochemical support to exclude the use of other pathways. Here, we demonstrate using various inhibitors that functional entry of baculoviruses into insect and mammalian cells is primarily dependent on clathrin-mediated endocytosis. Our results further suggest that caveolae are somehow involved in baculovirus entry in mammalian cells. A caveolar endocytosis inhibitor, genistein, enhances baculovirus transduction in these cells considerably.
Identification of Protective Lassa Virus Epitopes That Are Restricted by HLA-A2
Authors: Botten Jason , Alexander Jeff , Pasquetto Valerie , Sidney John , Barrowman Polly , Ting Joey , Peters Bjoern , Southwood Scott , Stewart Barbara , Rodriguez-Carreno Maria P. , Mothe Bianca , Whitton J. Lindsay , Sette Alessandro , Buchmeier Michael J. 
Published: August 2006

ABSTRACTRecovery from Lassa virus (LASV) infection usually precedes the appearance of neutralizing antibodies, indicating that cellular immunity plays a primary role in viral clearance. To date, the role of LASV-specific CD8+T cells has not been evaluated in humans. To facilitate such studies, we utilized a predictive algorithm to identify candidate HLA-A2 supertype epitopes from the LASV nucleoprotein and glycoprotein precursor (GPC) genes. We identified three peptides (GPC42-50, GLVGLVTFL; GPC60-68, SLYKGVYEL; and GPC441-449, YLISIFLHL) that displayed high-affinity binding (≤98 nM) to HLA-A*0201, induced CD8+T-cell responses of high functional avidity in HLA-A*0201 transgenic mice, and were naturally processed from native LASV GPC in human HLA-A*0201-positive target cells. HLA-A*0201 mice immunized with either GPC42-50or GPC60-68were protected against challenge with a recombinant vaccinia virus that expressed LASV GPC. The epitopes identified in this study represent potential diagnostic reagents and candidates for inclusion in epitope-based vaccine constructs. Our approach is applicable to any pathogen with existing sequence data, does not require manipulation of the actual pathogen or access to immune human donors, and should therefore be generally applicable to category A through C agents and other emerging pathogens.
Reovirus Outer Capsid Protein μ1 Induces Apoptosis and Associates with Lipid Droplets, Endoplasmic Reticulum, and Mitochondria
Authors: Coffey Caroline M. , Sheh Alexander , Kim Irene S. , Chandran Kartik , Nibert Max L. , Parker John S. L. 
Published: August 2006

ABSTRACT
The mechanisms by which reoviruses induce apoptosis have not been fully elucidated. Earlier studies identified the mammalian reovirus S1 and M2 genes as determinants of apoptosis induction. However, no published results have demonstrated the capacities of the proteins encoded by these genes to induce apoptosis, either independently or in combination, in the absence of reovirus infection. Here we report that the mammalian reovirus μ1 protein, encoded by the M2 gene, was sufficient to induce apoptosis in transfected cells. We also found that μ1 localized to lipid droplets, endoplasmic reticulum, and mitochondria in both transfected cells and infected cells. Two small
regions encompassing amphipathic α-helices within a carboxyl-terminal portion of μ1 were necessary for efficient
induction of apoptosis and association with lipid droplets, endoplasmic reticulum, and mitochondria in transfected cells. Induction of
apoptosis by μ1 and its association with lipid droplets and intracellular membranes in transfected cells were abrogated whenμ
1 was coexpressed with σ3, with which it is known to coassemble. We propose that μ1 plays a direct role in the
induction of apoptosis in infected cells and that this property may relate to the capacity of μ1 to associate with intracellular
membranes. Moreover, during reovirus infection, association with σ3 may regulate apoptosis induction byμ
1.
Differences and Similarities in Viral Life Cycle Progression and Host Cell Physiology after Infection of Human Dendritic Cells with Modified Vaccinia Virus Ankara and Vaccinia Virus
Authors: Chahroudi Ann , Garber David A. , Reeves Patrick , Liu Luzheng , Kalman Daniel , Feinberg Mark B. 
Published: August 2006

ABSTRACTModified vaccinia virus Ankara (MVA) is an attenuated strain of vaccinia virus (VV) that has attracted significant attention as a candidate viral vector vaccine for immunization against infectious diseases and treatment of malignancies. Although MVA is unable to replicate in most nonavian cells, vaccination with MVA elicits immune responses that approximate those seen after the administration of replication-competent strains of VV. However, the mechanisms by which these viruses elicit immune responses and the determinants of their relative immunogenicity are incompletely understood. Studying the interactions of VV and MVA with cells of the human immune system may elucidate these mechanisms, as well as provide a rational basis for the further enhancement of the immunogenicity of recombinant MVA vectors. Toward this end, we investigated the consequences of MVA or VV infection of human dendritic cells (DCs), key professional antigen-presenting cells essential for the generation of immune responses. We determined that a block to the formation of intracellular viral replication centers results in abortive infection of DCs with both VV and MVA. MVA inhibited cellular protein synthesis more rapidly than VV and displayed a distinct pattern of viral protein expression in infected DCs. MVA also induced apoptosis in DCs more rapidly than VV, and DC apoptosis after MVA infection was associated with an accelerated decline in the levels of intracellular Bcl-2 and Bcl-XL. These findings suggest that antigen presentation pathways may contribute differentially to the immunogenicity of VV and MVA and that targeted modifications of virus-induced DC apoptosis may further increase the immunogenicity of MVA-vectored vaccines.
FUNCTIONAL DECOMPOSITION — THE VALUE AND IMPLICATION FOR BOTH NEURAL NETWORKS AND DIGITAL DESIGNING
Authors: SELVARAJ HENRY , SAPIECHA PIOTR , RAWSKI MARIUSZ , ŁUBA TADEUSZ 
Published: August 2006

General functional decomposition is mainly perceived as a logic synthesis method for implementing Boolean functions into FPGA-based architectures. However it also has important applications in many other fields of modern engineering and science. In this paper, advantages of functional decomposition are demonstrated on "real life" examples. Application of decomposition-based methods in other fields of modern engineering is presented. In the case of decision tables, application of decomposition methods leads to significant benefits in the analysis process of data dependencies, especially in cases when the input decision tables are unmanageably large. Experimental results demonstrate that it can help implementing sequential machines using flip-flops or ROM memory. It also can be efficiently used as multilevel logic synthesis method for VLSI technology.
Inhibition of Phosphatidylinositol 3-Kinase Destabilizes Mycn Protein and Blocks Malignant Progression in Neuroblastoma
Authors: Chesler Louis , Schlieve Chris , Goldenberg David D. , Kenney Anna , Kim Grace , McMillan Alex , Matthay Katherine K. , Rowitch David , Weiss William A. 
Published: August 2006

AbstractAmplification of MYCN occurs commonly in neuroblastoma. We report that phosphatidylinositol 3-kinase (PI3K) inhibition in murine neuroblastoma (driven by a tyrosine hydroxylase-MYCN transgene) led to decreased tumor mass and decreased levels of Mycn protein without affecting levels of MYCN mRNA. Consistent with these observations, PI3K inhibition in MYCN-amplified human neuroblastoma cell lines resulted in decreased levels of Mycn protein without affecting levels of MYCN mRNA and caused decreased proliferation and increased apoptosis. To clarify the importance of Mycn as a target of broad-spectrum PI3K inhibitors, we transduced wild-type N-myc and N-myc mutants lacking glycogen synthase kinase 3β phosphorylation sites into human neuroblastoma cells with no endogenous expression of myc. In contrast to wild-type N-myc, the phosphorylation-defective mutant proteins were stabilized and were resistant to the antiproliferative effects of PI3K inhibition. Our results show the importance of Mycn as a therapeutic target in established tumors in vivo, offer a mechanistic rationale to test PI3K inhibitors in MYCN-amplified neuroblastoma, and represent a therapeutic approach applicable to a broad range of cancers in which transcription factors are stabilized through a PI3K-dependent mechanism. (Cancer Res 2006; 66(16): 8139-46)
Plasticity in Urokinase-Type Plasminogen Activator Receptor (uPAR) Display in Colon Cancer Yields Metastable Subpopulations Oscillating in Cell Surface uPAR Density—Implications in Tumor Progression
Authors: Yang Lin , Avila Hector , Wang Heng , Trevino Jose , Gallick Gary E. , Kitadai Yasuhiko , Sasaki Takamitsu , Boyd Douglas D. 
Published: August 2006

Abstract
It is becoming increasingly clear that tumor growth and progression is not entirely due to genetic aberrations but also reflective of tumor cell plasticity. It follows therefore that proteins contributing to tumor progression oscillate in their expression a contention yet to be shown. Because the urokinase-type plasminogen activator receptor (uPAR) promotes tumor growth and invasion, we determined whether its expression is itself plastic. In fluorescence-activated cell sorting (FACS), three independent colon cancer clonal populations revealed the expected Gaussian distribution for cell surface uPAR display. However, subcloning of cells collected from the trailing edge of the FACS yielded subpopulations, displaying low cell surface uPAR number. Importantly, these subclones spontaneously reverted to cells enriched in uPAR display, indicating a metastable phenotype. uPAR display plasticity was associated with divergent in vivo behavior with weak tumor growth and progression segregating with receptor deficiency. Mechanistically, reduced uPAR display reflected not repressed gene expression but a switch in uPAR protein trafficking from membrane insertion to shedding. To our knowledge, this is the first demonstration that uPAR cell surface density is oscillatory and we propose that such an event might well contribute to tumor progression. (Cancer Res 2006; 66(16): 7957-67)
Frequent Alterations in the Expression of Serine/Threonine Kinases in Human Cancers
Authors: Capra Maria , Nuciforo Paolo Giovanni , Confalonieri Stefano , Quarto Micaela , Bianchi Marco , Nebuloni Manuela , Boldorini Renzo , Pallotti Francesco , Viale Giuseppe , Gishizky Mikhail L. , Draetta Giulio F. , Di Fiore Pier Paolo 
Published: August 2006

Abstract
Protein kinases constitute a large family of regulatory enzymes involved in the homeostasis of virtually every cellular process. Subversion of protein kinases has been frequently implicated in malignant transformation. Within the family, serine/threonine kinases (STK) have received comparatively lesser attention, vis-a-vis tyrosine kinases, in terms of their involvement in human cancers. Here, we report a large-scale screening of 125 STK, selected to represent all major subgroups within the subfamily, on nine different types of tumors (∼200 patients), by using in situ hybridization on tissue microarrays. Twenty-one STK displayed altered levels of transcripts in tumors, frequently with a clear tumor type-specific dimension. We identified three patterns of alterations in tumors: (a) overexpression in the absence of expression in the normal tissues (10 kinases), (b) overexpression in the presence of expression by normal tissues (8 kinases), and (c) underexpression (3 kinases). Selected members of the three classes were subjected to in-depth analysis on larger case collections and showed significant correlations between their altered expression and biological and/or clinical variables. Our findings suggest that alteration in the expression of STK is a relatively frequent occurrence in human tumors. Among the overexpressed kinases, 10 were undetectable in normal controls and are therefore ideal candidates for further validation as potential targets of molecular cancer therapy. (Cancer Res 2006; 66(16): 8147-54)
Cyclin-Dependent Kinase 2 Functions in Normal DNA Repair and Is a Therapeutic Target in BRCA1-Deficient Cancers
Authors: Deans Andrew J. , Khanna Kum Kum , McNees Carolyn J. , Mercurio Ciro , Heierhorst Jörg , McArthur Grant A. 
Published: August 2006

AbstractAbnormal regulation of progression from G1 to S phase of the cell cycle by altered activity of cyclin-dependent kinases (CDKs) is a hallmark of cancer. However, inhibition of CDKs, particularly CDK2, has not shown selective activity against most cancer cells because the kinase seems to be redundant in control of cell cycle progression. Here, we show a novel role in the DNA damage response and application of CDK inhibitors in checkpoint-deficient cells. CDK2−/− mouse fibroblasts and small interfering RNA–mediated or small-molecule–mediated CDK2 inhibition in MCF7 or U2OS cells lead to delayed damage signaling through Chk1, p53, and Rad51. This coincided with reduced DNA repair using the single-cell comet assay and defects observed in both homologous recombination and nonhomologous end-joining in cell-based assays. Furthermore, tumor cells lacking cancer predisposition genes BRCA1 or ATM are 2- to 4-fold more sensitive to CDK inhibitors. These data suggest that inhibitors of CDK2 can be applied to selectively enhance responses of cancer cells to DNA-damaging agents, such as cytotoxic chemotherapy and radiotherapy. Moreover, inhibitors of CDKs may be useful therapeutics in cancers with defects in DNA repair, such as mutations in the familial breast cancer gene BRCA1. (Cancer Res 2006; 66(16): 8219-26)
Mechanisms of Tumor Regression and Resistance to Estrogen Deprivation and Fulvestrant in a Model of Estrogen Receptor–Positive, HER-2/neu-Positive Breast Cancer
Authors: Massarweh Suleiman , Osborne C. Kent , Jiang Shou , Wakeling Alan E. , Rimawi Mothaffar , Mohsin Syed K. , Hilsenbeck Susan , Schiff Rachel 
Published: August 2006

AbstractHER-2/neu in breast cancer is associated with tamoxifen resistance, but little data exist on its interaction with estrogen deprivation or fulvestrant. Here, we used an in vivo xenograft model of estrogen receptor (ER)-positive breast cancer with HER-2/neu overexpression (MCF7/HER-2/neu-18) to investigate mechanisms of growth inhibition and treatment resistance. MCF7/HER-2/neu-18 tumors were growth inhibited by estrogen deprivation and with fulvestrant, but resistance developed in 2 to 3 months. Inhibited tumors had reductions in ER, insulin-like growth factor-I receptor (IGF-IR), phosphorylated HER-2/neu (p-HER-2/neu), and phosphorylated p42/44 mitogen-activated protein kinase (p-MAPK). p27 was increased especially in tumors sensitive to estrogen deprivation. Tumors with acquired resistance to these therapies had complete loss of ER, increased p-HER-2/neu, increased p-MAPK, and reduced p27. In contrast, IGF-IR and phosphorylated AKT (p-AKT) levels were markedly reduced in these resistant tumors. The epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor gefitinib, which can block EGFR/HER-2/neu signaling, significantly delayed the emergence of resistance to both estrogen deprivation and fulvestrant. Levels of p-MAPK and p-AKT decreased with gefitinib, whereas high ER levels were restored. Eventually, however, tumors progressed in mice treated with gefitinib combined with estrogen deprivation or fulvestrant accompanied again by loss of ER and IGF-IR, increased p-HER-2/neu, high p-MAPK, and now increased p-AKT. Thus, estrogen deprivation and fulvestrant can effectively inhibit HER-2/neu-overexpressing tumors but resistance develops quickly. EGFR/HER-2/neu inhibitors can delay resistance, but reactivation of HER-2/neu and signaling through AKT leads to tumor regrowth. Combining endocrine therapy with EGFR/HER-2/neu inhibitors should be tested in clinical breast cancer, but a more complete blockade of EGFR/HER-2/neu may be optimal. (Cancer Res 2006; 66(16): 8266-73)
The Shaping of a Polyvalent and Highly Individual T-Cell Repertoire in the Bone Marrow of Breast Cancer Patients
Authors: Sommerfeldt Nora , Schütz Florian , Sohn Christoph , Förster Joanna , Schirrmacher Volker , Beckhove Philipp 
Published: August 2006

AbstractWe analyzed the T-cell repertoires from the bone marrow of 39 primary operated breast cancer patients and 11 healthy female donors for the presence and frequencies of spontaneously induced effector/memory T lymphocytes with peptide-HLA-A2-restricted reactivity against 10 breast tumor-associated antigens (TAA) and 3 normal breast tissue–associated antigens by short-term IFN-γ enzyme-linked immunospot (ELISpot) analysis. Sixty-seven percent of the patients recognized TAAs with a mean frequency of 144 TAA reactive cells per 106 T cells. These patients recognized simultaneously an average of 47% of the tested TAAs. The T-cell repertoire was highly polyvalent and exhibited pronounced interindividual differences in the pattern of TAAs recognized by each patient. Strong differences of reactivity were noticed between TAAs, ranging from 100% recognition of prostate-specific antigenp141-149 to only 25% recognition of MUC1p12-20 or Her-2/neup369-377. In comparison with TAAs, reactivity to normal breast tissue–associated antigens was lower with respect to the proportions of responding patients (30%) and recognized antigens (27%), with a mean frequency of only 85/106 T cells. Healthy individuals also contained TAA-reactive T cells but this repertoire was more restricted and the frequencies were in the same range as T cells reacting to normal breast tissue–associated antigens. Our data show a highly individual T-cell repertoire for recognition of TAAs in breast cancer patients. This has potential relevance for T-cell immune diagnostics, for tumor vaccine design, and for predicting immune responsiveness. (Cancer Res 2006; 66(16): 8258-65)
Joint Effects of Germ-Line p53 Mutation and Sex on Cancer Risk in Li-Fraumeni Syndrome
Authors: Wu Chih-Chieh , Shete Sanjay , Amos Christopher I. , Strong Louise C. 
Published: August 2006

Abstract
Germ-line p53 mutations have been identified in most families with Li-Fraumeni syndrome (LFS). For germ-line p53 mutation carriers, there is considerable variability with respect to age of cancer onset and tumor type, suggesting that additional genetic effects influence the clinical severity and tumor spectrum. To identify factors that might contribute to the observed heterogeneity in time to onset, we used segregation analysis to analyze the joint effects of germ-line p53 mutations and risk modifier(s) on cancer incidence. We studied 159 kindreds, ascertained through probands who had been diagnosed with childhood soft-tissue sarcoma before 16 years of age, survived &gt;3 years after diagnosis, and treated at The University of Texas M.D. Anderson Cancer Center (Houston, TX) from 1944 to 1975. This unique cohort has been followed systematically for &gt;20 years and has had germ-line p53 mutation testing in probands and extended family members. The analyses revealed that germ-line p53 mutations and sex had significant effects on cancer risk: men with p53 mutations had 151-fold higher odds of developing cancer than did those without mutations [95% confidence interval (95% CI), 60-380], and women with p53 mutations had 1,075-fold higher odds than did those without mutations (95% CI, 358-3,229) and 7.1-fold higher odds of having cancer than did men with mutations (95% CI, 2.5-20.3). These findings provide quantitative cancer risk assessments for LFS families. (Cancer Res 2006; 66(16): 8287-92)