bluuebunny/crossref_metadata_2025 huggingface dataset:
Time Frames for Neutralization during the Human Immunodeficiency Virus Type 1 Entry Phase, as Monitored in Synchronously Infected Cell Cultures
Authors: Haim Hillel , Steiner Israel , Panet Amos
Published: January 2007

Characterization of the neutralizing interaction between antibody and virus is hindered by the nonsynchronized progression of infection in cell cultures. Discrete steps of the viral entry sequence cannot be discerned, and thus, the mode of antibody-mediated interference with virus infectivity remains undefined. Here, we magnetically synchronize the motion and cell attachment of human immunodeficiency virus type 1 (HIV-1) to monitor the progression of neutralization, both in solution and following virus attachment to the cell. By simultaneous transfer of all viral particles from reaction solution with antibody to the cell-bound state, the precise rate of neutralization of cell-free virus could be determined for each antibody. HIV-1 neutralization by both monoclonal and polyclonal antibody preparations followed distinct pseudo-first-order kinetics. For all antibodies, cell types, and HIV-1 strains examined, postattachment interference served a major role in the neutralizing effect. To monitor the progression of postattachment interference, we synchronized the entry process at initiation and measured the escape of cell-bound virus from antibody. We found that different antibodies neutralized the virus over different time frames during the entry phase. Virus was observed to progress through a sequence of shifting sensitivities to different antibodies during entry, suggested here to correlate with the exposure time of the target epitope on receptor-activated viral envelope proteins. Thus, by monitoring the progression of HIV-1 entry under synchronized conditions, we identify a new and significant determinant of antibody neutralization capacity, namely, the time frames for neutralization during the course of the viral entry phase.
Inhibition of Human Immunodeficiency Virus Type 1 Infection of Human CD4
+
T Cells by Microbial HSP70 and the Peptide Epitope 407-426
Authors: Babaahmady Kaboutar , Oehlmann Wulf , Singh Mahavir , Lehner Thomas
Published: January 2007

Human immunodeficiency virus type 1 (HIV-1) virions contain heat shock proteins (HSP), but these proteins have received limited attention. The objectives of this study were to establish if the microbial 70-kDa HSP exerts an inhibitory effect on the HIV-1 infection of human CD4
+
T cells, to identify an inhibitory peptide epitope within the sequence of HSP70, and to evaluate the kinetic features of any inhibitory activity. The results of these studies suggest that microbial HSP70 exerts dose-dependent inhibition on CCR5 (R5) strains of clades B, C, and D of HIV-1 infecting human CD4
+
T cells. The site of the HIV-1-inhibitory function was identified within the C-terminal peptide binding domain of HSP70, and the function is expressed by the peptide epitope comprising amino acids 407 to 426. The mechanism of inhibition of HIV-1 infectivity by HSP70 is blocking of the CCR5 coreceptors directly and indirectly by inducing CC chemokines and APOBEC3G. The inhibitory effect of HSP70, its C-terminal fragment, or peptide 407-426 may make HSP70 useful as a microbicidal agent. A potentiating noncognate inhibition of HIV-1 infectivity by combined treatment with HSP70 and monoclonal or polyclonal antibody to CCR5 was demonstrated. This novel strategy may be utilized in therapeutic immunization against HIV-1 infection.
Subdominant CD8+T-Cell Responses Are Involved in Durable Control of AIDS Virus Replication
Authors: Friedrich Thomas C. , Valentine Laura E. , Yant Levi J. , Rakasz Eva G. , Piaskowski Shari M. , Furlott Jessica R. , Weisgrau Kimberly L. , Burwitz Benjamin , May Gemma E. , León Enrique J. , Soma Taeko , Napoe Gnankang , Capuano Saverio V. , Wilson Nancy A. , Watkins David I.
Published: January 2007

“Elite controllers” are individuals that durably control human immunodeficiency virus or simian immunodeficiency virus replication without therapeutic intervention. The study of these rare individuals may facilitate the definition of a successful immune response to immunodeficiency viruses. Here we describe six Indian-origin rhesus macaques that have controlled replication of the pathogenic virus SIVmac239 for 1 to 5 years. To determine which lymphocyte populations were responsible for this control, we transiently depleted the animals’ CD8+cells in vivo. This treatment resulted in 100- to 10,000-fold increases in viremia. When the CD8+cells returned, control was reestablished and the levels of small subsets of previously subdominant CD8+T cells expanded up to 2,500-fold above predepletion levels. This wave of CD8+T cells was accompanied by robust Gag-specific CD4 responses. In contrast, CD8+NK cell frequencies changed no more than threefold. Together, our data suggest that CD8+T cells targeting a small number of epitopes, along with broad CD4+T-cell responses, can successfully control the replication of the AIDS virus. It is likely that subdominant CD8+T-cell populations play a key role in maintaining this control.
Rat Cytomegalovirus Gene Expression in Cardiac Allograft Recipients Is Tissue Specific and Does Not Parallel the Profiles Detected In Vitro
Authors: Streblow Daniel N. , van Cleef Koen W. R. , Kreklywich Craig N. , Meyer Christine , Smith Patricia , Defilippis Victor , Grey Finn , Früh Klaus , Searles Robert , Bruggeman Cathrien , Vink Cornelis , Nelson Jay A. , Orloff Susan L.
Published: January 2007

Rat cytomegalovirus (RCMV) is a β-herpesvirus with a 230-kbp genome containing over 167 open reading frames (ORFs). RCMV gene expression is tightly regulated in cultured cells, occurring in three distinct kinetic classes (immediate early, early, and late). However, the extent of viral-gene expression in vivo and its relationship to the in vitro expression are unknown. In this study, we used RCMV-specific DNA microarrays to investigate the viral transcriptional profiles in cultured, RCMV-infected endothelial cells, fibroblasts, and aortic smooth muscle cells and to compare these profiles to those found in tissues from RCMV-infected rat heart transplant recipients. In cultured cells, RCMV expresses approximately 95% of the known viral ORFs with few differences between cell types. By contrast, in vivo viral-gene expression in tissues from rat heart allograft recipients is highly restricted. In the tissues studied, a total of 80 viral genes expressing levels twice above background (5,000 to 10,000 copies per μg total RNA) were detected. In each tissue type, there were a number of genes expressed exclusively in that tissue. Although viral mRNA and genomic DNA levels were lower in the spleen than in submandibular glands, the number of individual viral genes expressed was higher in the spleen (60 versus 41). This finding suggests that the number of viral genes expressed is specific to a given tissue and is not dependent upon the viral load or viral mRNA levels. Our results demonstrate that the profiles, as well as the amplitude, of viral-gene expression are tissue specific and are dramatically different from those in infected cultured cells, indicating that RCMV gene expression in vitro does not reflect viral-gene expression in vivo.
Sensing Infection by Adenovirus: Toll-Like Receptor-Independent Viral DNA Recognition Signals Activation of the Interferon Regulatory Factor 3 Master Regulator
Authors: Nociari Marcelo , Ocheretina Oksana , Schoggins John W. , Falck-Pedersen Erik
Published: January 2007

Infection with adenovirus vectors (AdV) results in rapid activation of innate immunity, which serves the dual purpose of stimulating inflammatory antiviral host defenses and the adaptive immune system. Viral recognition by macrophages, dendritic cells, and other cell types requires an ability to sense the presence of a foreign molecular pattern by “pattern recognition receptors.” The nature of the adenoviral sensor, the target ligand of the sensor, and the downstream antiviral signaling response triggered by virus infection have not been defined for this nonenveloped double-stranded DNA (dsDNA) virus. We have identified four critical links involved in AdV recognition by murine antigen-presenting cells (APC) and primary lung fibroblasts: (i) viral recognition occurs chiefly via a Toll-like receptor (TLR)-independent nucleic acid-sensing mechanism recognizing the viral dsDNA genome, (ii) the intact viral particle and capsid proteins are required for efficient intracellular delivery of the viral genome, (iii) delivery of the viral genome triggers interferon regulatory factor 3 (IRF3) phosphorylation, and (iv) IRF3 activation is the required dominant antiviral signaling pathway used by APC, whereas the “primary” involvement of NF-κB, mitogen-activated protein kinase, or Akt pathways is less prominent. In this study we provide the first direct evidence that infection by a dsDNA virus stimulates an IRF3-mediated interferon and proinflammatory response through a TLR-independent DNA-sensing mechanism.
Influence of Coagulation Factor Zymogens on the Infectivity of Adenoviruses Pseudotyped with Fibers from Subgroup D
Authors: Parker Alan L. , McVey John H. , Doctor Jessica H. , Lopez-Franco Oscar , Waddington Simon N. , Havenga Menzo J. E. , Nicklin Stuart A. , Baker Andrew H.
Published: January 2007

Recent evidence supports a role for vitamin K-dependent coagulation zymogens in adenovirus serotype 5 (Ad5, subgroup C) infection of hepatocytes. Here, we assessed the effect of virus-zymogen interaction on cellular transduction using a panel of fiber (f)-pseudotyped viruses derived from subgroup D (f47, f33, f24, f45, f17, f30). Each virus directly bound factor X (FX) as determined by surface plasmon resonance, resulting in enhanced cell surface binding. Infection of HepG2 cells was promoted by FX but not by FVII or FIX, while transduction of CHO cells was blocked in heparan sulfate proteoglycan-deficient cells. This suggests a broad role for FX in adenovirus infectivity.
GAMES OF INNOVATION: A NEW THEORETICAL PERSPECTIVE
Authors: MILLER ROGER , FLORICEL SERGHEI
Published: January 2007

Games of innovation are sets of rules that structure meso-level innovation systems composed of organisational actors that compete and collaborate to create value. All game rules are coherent, with one dominant value-creation logic, and refer to all the aspects of managing innovation, from competitive strategies and policies for investment in innovation capabilities to practices for identifying opportunities and managing projects. The dominant logic that guides them stems from prevailing conditions for innovation, which open certain avenues by which participants produce and capture value, but which close others. The rules stabilise and ensure the reproduction of innovation systems for long periods of time.
CONTINGENT ORGANISING FOR GAMES OF INNOVATION: DIVERSE CONFIGURATIONS OF CORE PRINCIPLES FOR INNOVATIVE ORGANISATIONAL DESIGN
Authors: DOUGHERTY DEBORAH
Published: January 2007

This paper leverages current thinking on organising for innovation to create new ideas on contingent organising for innovation. I argue that all successfully innovative organisations need to be built on the same higher-level principles of innovative organising, but the relative emphasis on which principles and how they are implemented will vary by game of innovation. I focus on four organising activities: defining the work that will be done, differentiating that work into coherent units, integrating those differentiated units, and controlling the whole system over time. I synthesise the literature into four principles of innovative organising: defining innovative work as professional practice; differentiating innovative work into domains of practice; integrating these domains via strategic sensemaking, and controlling the work with social rules. Finally, particular configurations of these principles are developed for various MINE games of innovation, based on the dynamics of each game.
Enhanced suicidal death of erythrocytes from gene-targeted mice lacking the Cl−/HCO3− exchanger AE1
Authors: Akel Ahmad , Wagner Carsten A. , Kovacikova Jana , Kasinathan Ravi. S. , Kiedaisch Valentin , Koka Saisudha , Alper Seth L. , Bernhardt Ingolf , Wieder Thomas , Huber Stephan M. , Lang Florian
Published: January 2007

Genetic defects of anion exchanger 1 (AE1) may lead to spherocytic erythrocyte morphology, severe hemolytic anemia, and/or cation leak. In normal erythrocytes, osmotic shock, Cl− removal, and energy depletion activate Ca2+-permeable cation channels with Ca2+-induced suicidal erythrocyte death, i.e., surface exposure of phosphatidylserine, cell shrinkage, and membrane blebbing, all features typical for apoptosis of nucleated cells. The present experiments explored whether AE1 deficiency favors suicidal erythrocyte death. Peripheral blood erythrocyte numbers were significantly smaller in gene-targeted mice lacking AE1 ( AE1−/− mice) than in their wild-type littermates ( AE1+/+ mice) despite increased percentages of reticulocytes ( AE1−/−: 49%, AE1+/+: 2%), an indicator of enhanced erythropoiesis. Annexin binding, reflecting phosphatidylserine exposure, was significantly larger in AE1−/−erythrocytes/reticulocytes (∼10%) than in AE1+/+ erythrocytes (∼1%). Osmotic shock (addition of 400 mM sucrose), Cl− removal (replacement with gluconate), or energy depletion (removal of glucose) led to significantly stronger annexin binding in AE1−/− erythrocytes/reticulocytes than in AE1+/+ erythrocytes. The increase of annexin binding following exposure to the Ca2+ ionophore ionomycin (1 μM) was, however, similar in AE1−/− and in AE1+/+ erythrocytes. Fluo3 fluorescence revealed markedly increased cytosolic Ca2+ permeability in AE1−/− erythrocytes/reticulocytes. Clearance of carboxyfluorescein diacetate succinimidyl ester-labeled erythrocytes/reticulocytes from circulating blood was more rapid in AE1−/− mice than in AE1+/+ mice and was accelerated by ionomycin treatment in both genotypes. In conclusion, lack of AE1 is associated with enhanced Ca2+ entry and subsequent scrambling of cell membrane phospholipids.
Mouse colon sensory neurons detect extracellular acidosis via TRPV1
Authors: Sugiura Takeshi , Bielefeldt Klaus , Gebhart G. F.
Published: January 2007

Extracellular acidification contributes to pain by activating or modulating nociceptor activity. To evaluate acidic signaling from the colon, we characterized acid-elicited currents in thoracolumbar (TL) and lumbosacral (LS) dorsal root ganglion (DRG) neurons identified by content of a fluorescent dye (DiI) previously injected into the colon wall. In 13% of unidentified LS DRG neurons (not labeled with DiI) and 69% of LS colon neurons labeled with DiI, protons activated a sustained current that was significantly and reversibly attenuated by the transient receptor potential vanilloid receptor 1 (TRPV1) antagonist capsazepine. In contrast, 63% of unidentified LS DRG neurons and 4% of LS colon neurons exhibited transient amiloride-sensitive acid-sensing ion channel (ASIC) currents. The peak current density of acid-elicited currents was significantly reduced in colon sensory neurons from TRPV1-null mice, supporting predominant expression of TRPV1 in LS colon sensory neurons, which was also confirmed immunohistochemically. Similar to LS colon DRG neurons, acid-elicited currents in TL colon DRG neurons were mediated predominantly by TRPV1. However, the pH producing half-activation of responses significantly differed between TL and LS colon DRG neurons. The properties of acid-elicited currents in colon DRG neurons suggest differential contributions of ASICs and TRPV1 to colon sensation and likely nociception.
Fiber types in canine muscles: myosin isoform expression and functional characterization
Authors: Toniolo Luana , Maccatrozzo Lisa , Patruno Marco , Pavan Elisabetta , Caliaro Francesca , Rossi Rosetta , Rinaldi Chiara , Canepari Monica , Reggiani Carlo , Mascarello Francesco
Published: January 2007

This study was aimed to achieve a definitive and unambiguous identification of fiber types in canine skeletal muscles and of myosin isoforms that are expressed therein. Correspondence of canine myosin isoforms with orthologs in other species as assessed by base sequence comparison was the basis for primer preparation and for expression analysis with RT-PCR. Expression was confirmed at protein level with histochemistry, immunohistochemistry, and SDS-PAGE combined together and showed that limb and trunk muscles of the dog express myosin heavy chain (MHC) type 1, 2A, and 2X isoforms and the so-called “type 2dog” fibers express the MHC-2X isoform. MHC-2A was found to be the most abundant isoform in the trunk and limb muscle. MHC-2X was expressed in most but not all muscles and more frequently in hybrid 2A-2X fibers than in pure 2X fibers. MHC-2B was restricted to specialized extraocular and laryngeal muscles, although 2B mRNA, but not 2B protein, was occasionally detected in the semimembranosus muscle. Isometric tension (Po) and maximum shortening velocity ( Vo) were measured in single fibers classified on the basis of their MHC isoform composition. Purified myosin isoforms were extracted from single muscle fibers and characterized by the speed ( Vf) of actin filament sliding on myosin in an in vitro motility assay. A close proportionality between Vo and Vf indicated that the diversity in Vo was due to the different myosin isoform composition. Vo increased progressively in the order 1/slow < 2A < 2X < 2B, thus confirming the identification of the myosin isoforms and providing their first functional characterization of canine muscle fibers.
On Use of a Nominal Internal Model to Detect a Loss of Balance in a Maximal Forward Reach
Authors: Ahmed Alaa A. , Ashton-Miller James A.
Published: January 2007

We hypothesize that the CNS detects a loss of balance by comparing outputs predicted by a nominal, forward internal model with actual sensory outputs. When the resulting control error signal reaches an anomalously large value, this control error anomaly (CEA) signals a loss of balance and precedes any observable compensatory response. To test this hypothesis, a multi-input, multi-output internal model of a standing forward reach task was developed that incorporated on-line model identification and a Gaussian failure detection algorithm. Eleven healthy young women were then asked to stand and reach forward to a target positioned from 95 to 125% of their maximum reach distance. Kinematic and kinetic data were recorded at 100 Hz unilaterally from the upper body, leg, and foot. Evidence of successful CEA detection was a compensatory step between 100 ms and 2 s later. The results show that use of a threshold, set at 3 SD from the mean, on error in the control of leg segment acceleration detected a CEA and correctly predicted a compensatory response in 92.6% of 108 trials. Leg acceleration control error was a better predictor than upper body or foot acceleration control error ( P = 0.000). CEA detection performed more reliably than loss of balance detection algorithms based on kinematic thresholds ( P = 0.000). The results support the hypothesis that a loss of balance may be identified via the use of a nominal forward internal model and probabilistic error monitoring.
Changes in Spinal Excitability After PAS
Authors: Meunier Sabine , Russmann Heike , Simonetta-Moreau Marion , Hallett Mark
Published: January 2007

Repetitive pairing of a peripheral stimulation with a magnetic transcortical stimulation (PAS) is widely used to induce plastic changes in the human motor cortex noninvasively. Based on the contrast between PAS-induced increase of corticospinal excitability and absence of PAS-induced increase of the spinal F wave size, it has been generally accepted that PAS-induced plasticity is cortical in origin. Here, instead of F waves, we used H reflex recruitment curves to assess spinal excitability, and we demonstrate that PAS induces parallel changes in cortical and spinal excitability.
Induction of dendritic cell-like phenotype in macrophages during foam cell formation
Authors: Cho Hyung Jun , Shashkin Pavel , Gleissner Christian A. , Dunson Dane , Jain Nitin , Lee Jae K. , Miller Yury , Ley Klaus
Published: January 2007

Foam cell formation from monocyte-derived macrophages is a hallmark of atherosclerotic lesions. Aspects of this process can be recapitulated in vitro by exposing M-CSF-induced or platelet factor 4 (CXCL4)-induced macrophages to oxidized (ox) or minimally modified (mm) low density lipoprotein (LDL). We measured gene expression in peripheral blood mononuclear cells, monocytes, and macrophages treated with CXCL1 (GRO-α) or CCL2 (MCP-1), as well as foam cells induced by native LDL, mmLDL, or oxLDL using 22 Affymetrix gene chips. Using an advanced Bayesian error-pooling approach and a heterogeneous error model with a false discovery rate <0.05, we found 5,303 of 22,215 probe sets to be significantly regulated in at least one of the conditions. Among a subset of 917 candidate genes that were preselected for their known biological functions in macrophage foam-cell differentiation, we found that 290 genes met the above statistical criteria for significant differential expression patterns. While many expected genes were found to be upregulated by LDL and oxLDL, very few were induced by mmLDL. We also found induction of unexpected genes, most strikingly MHC-II and other dendritic cell markers such as CD11c. The gene expression patterns in response to oxLDL were similar in M-CSF-induced and CXCL4-induced macrophages. Our findings suggest that LDL and oxLDL, but not mmLDL, induce a dendritic cell-like phenotype in macrophages, suggesting that these cells may be able to present antigens and support an immune response.
Circulating Mitochondrial Nucleic Acids Have Prognostic Value for Survival in Patients with Advanced Prostate Cancer
Authors: Mehra Niven , Penning Maarten , Maas Jolanda , van Daal Nancy , Giles Rachel H. , Voest Emile E.
Published: January 2007

Purpose: Advanced prostate cancer represents a heterogeneous disease entity with differences in clinical behavior, response to therapy, and survival. We assessed whether we could distinguish poor from good prognosis patients at presentation in our clinic by means of quantifying circulating cell-free mitochondrial and genomic nucleic acids in plasma.

Experimental Design: We collected plasma from 75 prostate cancer patients and from 14 subjects with benign disease. Nucleic acids were isolated, and mitochondrial DNA (mtDNA; 16S rRNA), mitochondrial RNA (mtRNA; cytochrome c oxidase subunit 1), and genomic DNA (U1A DNA) transcripts were quantified by real-time amplification. An association between cell-free nucleic acids and metastasis, prostate-specific antigen doubling time, and hemoglobin levels was determined. Multivariate Cox proportional hazard and survival estimation studies were done.

Results: We show that elevated mtDNA and mtRNA levels are present in plasma of prostate cancer patients with a poor 2-year survival (P = 0.02 and 0.003, respectively). Cancer patients with high plasma mitochondrial nucleic acids, using a calculated optimal cutoff point, show a decreased survival compared with patients with low levels (35% versus 73% cumulative survival for mtDNA and 21% versus 73% for mtRNA). Multivariate analysis indicates that mtRNA is an independent predictor of 2-year survival.

Conclusions: Quantification of plasma mitochondrial nucleic acids may be used to recognize patients with a poor prognosis. In advanced prostate cancer patients, mtRNA seemed the strongest predictor of overall survival and an independent prognostic factor for cancer-related death. Amplification of mitochondrial nucleic acids shows increased sensitivity and specificity over genomic DNA as diagnostic and prognostic marker in prostate cancer patients.
Decreased NKG2D Expression on CD8+ T Cell Is Involved in Immune Evasion in Patients with Gastric Cancer
Authors: Osaki Tomohiro , Saito Hiroaki , Yoshikawa Toshiaki , Matsumoto Sachiko , Tatebe Shigeru , Tsujitani Shunichi , Ikeguchi Masahide
Published: January 2007

Purpose: Some studies suggest that the immunoreceptor NKG2D expression on CD8+ T cells is down-regulated and this reduction may be involved in immune evasion in cancer patients. The present study was designed to investigate NKG2D expression on CD8+ T lymphocytes and its relationship to immune evasion in gastric cancer patients.

Experimental Design: NKG2D expression on both circulating and tumor-infiltrating CD8+ T cells was evaluated by multicolor flow cytometry. Soluble MHC class I chain-related gene A (MICA) in the sera was quantitated by ELISA. Transwell experiments were carried out to determine the effect of cancer cells on NKG2D expression.

Results: NKG2D expression on circulating CD8+ T cells was down-regulated and significantly correlated with IFN-γ production in gastric cancer patients (r = 0.68; P = 0.007). NKG2D expression was closely related to undifferentiated cancer (P = 0.021) as was the depth of invasion (P = 0.012). There was no difference in soluble MICA between gastric cancer patients and normal controls. NKG2D expression on CD8+ T cells was remarkably reduced in the tissue of gastric cancer compared with peripheral blood (P = 0.046). Complete removal of tumor by surgery restored NKG2D expression on CD8+ T cells (P = 0.0049). Transwell experiments showed that this down-regulation was induced by direct contact between cancer cells and CD8+ T cells and that soluble factors did not affect the NKG2D expression. This phenomenon was blocked by the addition of anti-MICA antibodies.

Conclusions: Decreased NKG2D expression may be one of the key mechanisms responsible for immune evasion by tumors in gastric cancer.
The von Hippel-Lindau Tumor Suppressor Protein and Clear Cell Renal Carcinoma
Authors: Kaelin William G.
Published: January 2007

Germ line VHL tumor suppressor gene loss-of-function mutations cause von Hippel-Lindau disease, which is associated with an increased risk of central nervous system hemangioblastomas, clear cell renal carcinomas, and pheochromocytomas. Somatic VHL mutations are also common in sporadic clear cell renal carcinomas. The VHL gene product, pVHL, is part of a ubiquitin ligase complex that targets the α-subunits of the heterodimeric transcription factor hypoxia-inducible factor (HIF) for polyubiquitylation, and hence, proteasomal degradation, when oxygen is available. pVHL-defective clear cell renal carcinomas overproduce a variety of mRNAs that are under the control of HIF, including the mRNAs that encode vascular endothelial growth factor, platelet-derived growth factor B, and transforming growth factor α. In preclinical models, down-regulation of HIF-α, especially HIF-2α, is both necessary and sufficient for renal tumor suppression by pVHL. These observations are probably relevant to the demonstrated clinical activity of vascular endothelial growth factor antagonists in clear cell renal carcinoma and form a foundation for the testing of additional agents that inhibit HIF, or HIF-responsive gene products, in this disease.
Implications of B7-H1 Expression in Clear Cell Carcinoma of the Kidney for Prognostication and Therapy
Authors: Thompson R. Houston , Dong Haidong , Kwon Eugene D.
Published: January 2007

B7-H1 encompasses a recently discovered cell surface glycoprotein within the B7 family of T-cell coregulatory molecules. B7-H1 expression can be induced on activated T lymphocytes and is normally expressed by macrophage lineage cells. In addition, some human tumors acquire the ability to aberrantly express B7-H1. Tumor-associated B7-H1, as well as B7-H1 on activated lymphocytes, has been shown to impair antigen-specific T-cell function and survival in vitro. In contrast, in vivo monoclonal antibody–mediated blockade of B7-H1 has been shown to potentiate antitumoral responses in several murine cancer models. Consequently, tumor-associated B7-H1 has garnered much attention in the recent literature as a potential inhibitor of host antitumoral immunity. Our group has recently reported that B7-H1 is aberrantly expressed in both primary and metastatic renal cell carcinoma (RCC) as revealed via immunohistochemical staining of both fresh-frozen and paraffin-embedded nephrectomy specimens. In addition, we have shown that B7-H1 expression by clear cell RCC tumors (or infiltrating mononuclear cells) correlates with aggressive pathologic features, including advanced tumor-node-metastasis stage, tumor size, higher nuclear grade, and coagulative necrosis. In one study of 306 patients, with a median clinical follow-up of 11 years, we reported that RCC B7-H1 expression correlates with increased risk of disease progression, cancer-specific death, and overall mortality even after multivariate adjustment. Five-year cancer-specific survival rates in this study were 42% and 83% for patients harboring B7-H1+ versus B7-H1− RCC tumors, respectively. Such associations may relate to the recognized ability of B7-H1 to inhibit T-cell–mediated antitumoral immunity. In summary, B7-H1 encompasses a potent independent predictor of prognosis for patients with RCC and an extremely promising target to facilitate immunotherapeutic responses during the management of this treatment-refractory tumor.
Identification of the Genes for Kidney Cancer: Opportunity for Disease-Specific Targeted Therapeutics
Authors: Linehan W. Marston , Pinto Peter A. , Srinivasan Ramaprasad , Merino Maria , Choyke Peter , Choyke Lynda , Coleman Jonathan , Toro Jorge , Glenn Gladys , Vocke Cathy , Zbar Bert , Schmidt Laura S. , Bottaro Donald , Neckers Len
Published: January 2007

Recent advances in understanding the kidney cancer gene pathways has provided the foundation for the development of targeted therapeutic approaches for patients with this disease. Kidney cancer is not a single disease; it includes a number of different types of renal cancers, each with different histologic features, a different clinical course, a different response to therapy, and different genes causing the defects. Most of what is known about the genetic basis of kidney cancer has been learned from study of the inherited forms of kidney cancer: von Hippel Lindau (VHL gene), hereditary papillary renal carcinoma (c-Met gene), Birt Hogg Dubé (BHD gene), and hereditary leiomyomatosis renal cell cancer (fumarate hydratase gene). These Mendelian single-gene syndromes provide a unique opportunity to evaluate the effectiveness of agents that target the VHL, c-Met, BHD, and fumarate hydratase pathways.
Prospective Early Response Imaging Biomarker for Neoadjuvant Breast Cancer Chemotherapy
Authors: Lee Kuei C. , Moffat Bradford A. , Schott Anne F. , Layman Rachel , Ellingworth Steven , Juliar Rebecca , Khan Amjad P. , Helvie Mark , Meyer Charles R. , Chenevert Thomas L. , Rehemtulla Alnawaz , Ross Brian D.
Published: January 2007

Purpose: The American Cancer Society estimates that in 2006, 212,920 women will be diagnosed with breast cancer and that 40,970 women will die from the disease. The development of more efficacious chemotherapies has improved outcomes, but the rapid assessment of clinical benefit from these agents remains challenging. In breast cancer patients receiving neoadjuvant chemotherapy, treatment response is traditionally assessed by physical examination and volumetric-based measurements, which are subjective and require macroscopic changes in tumor morphology. In this study, we evaluate the feasibility of using diffusion magnetic resonance imaging (MRI) as a reliable and quantitative measure for the early assessment of response in a breast cancer model.

Experimental Design: Mice implanted with human breast cancer (MX-1) were treated with cyclophosphamide and evaluated using diffusion MRI and growth kinetics. Histologic analyses using terminal nucleotidyl transferase–mediated nick end labeling and H&E were done on tumor samples for correlation with imaging results.

Results: Cyclophosphamide treatment resulted in a significant reduction in tumor volumes compared with controls. The mean apparent diffusion change for treated tumors at days 4 and 7 posttreatment was 44 ± 5% and 94 ± 7%, respectively, which was statistically greater (P < 0.05) than the control tumors at the same time intervals. The median time-to-progression for control and treated groups was 11 and 32 days, respectively (P < 0.05).

Conclusion: Diffusion MRI was shown to detect early changes in the tumor microenvironment, which correlated with standard measures of tumor response as well as overall outcome. Moreover, these findings show the feasibility of using diffusion MRI for assessing treatment response of a breast tumor model in a neoadjuvant setting.
Biomarkers for Monitoring Antiangiogenic Therapy
Authors: Bhatt Rupal S. , Seth Pankaj , Sukhatme Vikas P.
Published: January 2007

A variety of antiangiogenic agents are currently available for the treatment of renal cell carcinoma. With these exciting new therapeutic agents comes the challenge of elucidating useful biomarkers to monitor patients receiving these therapies. Although many patients benefit from antiangiogenic therapies, it is often by achieving stability of their disease. Thus, development of noninvasive biomarkers of disease response and relapse is a crucial objective to aid in the management of patients. The current technologies being explored in this field include circulating plasma proteins, cells, and nucleic acids and novel imaging techniques. Surrogate markers of angiogenesis could help with selecting patients for therapy, determining optimal dosing of therapy, deciding whether to change therapy, and assessing appropriate salvage therapy.
Reversal of Tumor-Mediated Immunosuppression
Authors: Vieweg Johannes , Su Zhen , Dahm Philipp , Kusmartsev Sergei
Published: January 2007

Therapeutic cancer vaccines, one form of active immunotherapy, have long been under investigation; consequently, several vaccine-based strategies have now moved from the bench to the clinical arena. Despite their tremendous promise, current vaccine strategies have shown only limited success in clinical settings, even in renal cell carcinoma (RCC), a prototypical malignancy for the application of immunotherapy. There is ample evidence that, especially in RCC, multiple immunosuppressive mechanisms exist that considerably dampen antitumor responses and weaken the activity of current immunotherapeutic regimens. Therefore, it will be necessary to reverse tumor-mediated immunosuppression before immunotherapies can successfully be applied. Recent insights into the nature and characteristics of the regulatory elements of the immune system have provided new opportunities to enhance vaccine-mediated antitumor immunity and, thereby, increase the chance for improving patient outcome. These new insights represent important considerations for the future design and application of more effective cancer vaccines against RCC and other cancers.
PTEN-Mediated Resistance to Epidermal Growth Factor Receptor Kinase Inhibitors
Authors: Mellinghoff Ingo K. , Cloughesy Tim F. , Mischel Paul S.
Published: January 2007

Molecularly targeted therapies are transforming the treatment of cancer. Elucidating the dynamic signaling networks that underlie sensitivity and resistance to these inhibitors is critical for successful clinical application. There is considerable evidence to suggest that constitutively activating mutations in kinases that regulate cellular growth may result in tumor cell “addiction” and favorable response to targeted inhibition. However, there is emerging evidence to suggest that clinical response may also be determined by other changes in the molecular circuitry of cancer cells, such as loss of key tumor-suppressor proteins. Here, we will discuss resistance to epidermal growth factor receptor tyrosine kinase inhibitors in glioblastoma patients that is mediated by loss of the PTEN tumor-suppressor protein.
Sorafenib in Renal Cell Carcinoma
Authors: Flaherty Keith T.
Published: January 2007

Sorafenib is an orally available inhibitor of vascular endothelial growth factor receptors, platelet-derived growth factor receptor-β, and RAF kinases. A dose of 400 mg twice daily administered continuously was selected for phase 2 testing, although 600 mg twice daily formally met criteria for a maximum tolerated dose. It is well tolerated compared with cytokine therapy. Antitumor activity was shown clearly in the context of a randomized discontinuation phase 2 trial. In this setting, even disease stabilization was established as a treatment-related phenomenon. A phase 3 trial with sorafenib confirmed a benefit of therapy across the vast majority of patients treated with sorafenib as opposed to placebo. Limited investigations into the mechanism of action of sorafenib in renal cell carcinoma support vascular endothelial growth factor receptor antagonism as the primary mediator of effect. The toxicity profile of sorafenib allows for its use in combination regimens. The focus of efforts to improve on the efficacy of sorafenib is on use with IFN, bevacizumab, or temsirolimus. Preliminary evidence with this approach is promising and will be the subject of the next generation of randomized trials in renal cell carcinoma.
Prognostic Role of the Reduced Folate Carrier, the Major Membrane Transporter for Methotrexate, in Childhood Acute Lymphoblastic Leukemia: A Report from the Children's Oncology Group
Authors: Ge Yubin , Haska Christina L. , LaFiura Katherine , Devidas Meenakshi , Linda Stephen B. , Liu Mingjun , Thomas Ronald , Taub Jeffrey W. , Matherly Larry H.
Published: January 2007

Purpose: The value of measuring expression of individual genes relevant to particular chemotherapy drugs and encoding metabolizing enzymes, transporters, or drug targets, as predictors of treatment response and outcome in pediatric acute lymphoblastic leukemia (ALL), remains controversial.

Experimental Design: In a case-control population of 91 pediatric B-precursor ALL patients [42 relapsed within 4 years (cases) and 49 did not relapse (controls)], we used real-time reverse transcription-PCR to measure transcript levels for 20 genes relevant to chemotherapy with the five major drugs used to treat this disease, including asparaginase, 6-mercaptopurine, methotrexate, prednisone, and vincristine. Results were confirmed in a separate case-control population of 26 patients.

Results: Only the human reduced folate carrier (hRFC) gene, encoding the major membrane transporter for methotrexate, showed a significant difference in median transcript levels between the 42 cases and the 49 controls (P = 0.0278, Wilcoxon test). Using cutoffs for hRFC expression levels (based on Akaike information criterion), there were statistically significant associations between hRFC transcripts and treatment relapse (P = 0.0052). hRFC-B, corresponding to the major hRFC transcript form in ALL, was also measured by real-time reverse transcription-PCR and was prognostic. The association between treatment relapse and hRFC levels was validated in a separate study population of 14 cases and 12 controls from an earlier case-control study (P = 0.0221).

Conclusions: Our results strongly suggest the prognostic importance of hRFC gene expression to treatment outcomes in pediatric ALL. They validate our previous studies of hRFC transcriptional regulation in pediatric ALL and provide further compelling evidence for the critical role for methotrexate in the successful treatment of this disease.
Arginase, Prostaglandins, and Myeloid-Derived Suppressor Cells in Renal Cell Carcinoma
Authors: Ochoa Augusto C. , Zea Arnold H. , Hernandez Claudia , Rodriguez Paulo C.
Published: January 2007

Tumor-induced tolerance is a well-established phenomenon in cancer patients that can severely impair the therapeutic efficacy of immunotherapy. One mechanism leading to T-cell tolerance is the generation of myeloid-derived suppressor cells (MDSC) by soluble factors produced by the tumor. MDSC express CD11b+ as a common marker but may vary in their stage of maturation, depending on the tumor factors being produced. Arginase production by MDSC depletes arginine from the tumor microenvironment and impairs T-cell signal transduction and function. We studied whether an increase in MDSC could explain the molecular alterations and dysfunction found in T cells of patients with renal cell carcinoma (RCC). Arginase activity in the peripheral blood mononuclear cells of 117 RCC patients was increased between 6- to 8-fold compared with normal controls. The increased arginase activity was limited to the CD11b+CD14− myeloid cells and resulted in significantly decreased serum levels of arginine and increased ornithine in patients. Depletion of MDSC restored IFN-γ production and T-cell proliferation. Preliminary data suggest that prostaglandin E2 produced by the tumor induces arginase I expression in MDSC. Therefore, blocking MDSC activity may enhance the therapeutic efficacy of immunotherapy in RCC.
Innovations and Challenges in Renal Cell Carcinoma: Summary Statement from the Second Cambridge Conference
Authors: Atkins Michael B. , Ernstoff Marc S. , Figlin Robert A. , Flaherty Keith T. , George Daniel J. , Kaelin William G. , Kwon Eugene D. , Libermann Towia A. , Linehan W. Marston , McDermott David F. , Ochoa Augusto C. , Pantuck Allan J. , Rini Brian I. , Rosen Mark A. , Sosman Jeffrey A. , Sukhatme Vikas P. , Vieweg Johannes W. , Wood Christopher G. , King Laura
Published: January 2007

Innovations and Challenges in Renal Cancer, chaired by Michael B. Atkins, was held April 28 to 29, 2006 in Cambridge, Massachusetts. The conference brought together leading experts in the fields of cancer research, medical oncology, urology, immunology, radiology, and immunotherapy, with the goal of advancing the field of renal cancer treatment by critiquing new data from ongoing clinical trials and stimulating communication among those involved in basic and clinical research. The conference proceedings published in this educational supplement to Clinical Cancer Research are intended to provide timely information and recommendations on important aspects of renal cancer genetics and biology and advances in prognostic classification and treatment.
Skeletal Muscle as a Metabolic Target for Growth Hormone
Authors: Jørgensen Jens O.L. , Vestergaard Esben T. , Krag Morten , Nielsen Charlotte , Møller Louise , Gormsen Lars , Jessen Niels
Published: January 2007

Skeletal muscle is the major constituent of lean body mass and a major determinant of energy expenditure, both at rest and during physical activity. Growth hormone (GH), in turn, influences muscle mass as well as energy expenditure. GH substitution in adults increases muscle mass by 5–10%, but part of this is attributed to rehydration. In addition, GH increases resting energy expenditure independently of muscle mass, via mechanisms that may include increased conversion of the thyroid hormones thyroxine (T4) to tri-iodothyronine (T3) and stimulation of skeletal muscle blood flow. In addition, GH regulates substrate metabolism in muscle and, in particular, antagonizes insulin-stimulated glucose disposal. This effect is linked to increased free fatty acid flux, but the molecular mechanisms remain unclear. During fasting, GH-induced insulin resistance may be favourable by reducing the demand for gluconeogenesis from protein. In the postprandial phase, however, GH exposure may compromise glucose tolerance via the same mechanisms. Understanding the mechanisms by which GH antagonizes insulin-stimulated glucose disposal in muscle is an important future research field, with implications for a variety of clinical conditions ranging from malnutrition to obesity and type 2 diabetes mellitus.
Growth Hormone and Testosterone: Effects on Whole Body Metabolism and Skeletal Muscle in Adolescence
Authors: Mauras Nelly
Published: January 2007

The characteristic changes in human puberty – increased muscle bulk, increased linear growth, and the mineralization of the skeleton – are due, in part, to the combined effects of growth hormone (GH), insulin-like growth factor I (IGF-I), sex hormones and insulin. GH and testosterone, but not oestrogen, are highly protein-anabolic in vivo, and the combined administration of GH and testosterone has synergistic effects on these measures, both in children and adults. GH has no significant effect on enhancing skeletal muscle strength in humans; however, testosterone is highly ergogenic and is largely responsible for the differences in muscle bulk apparent in late puberty between the genders. The results of recent detailed metabolic studies suggest that boys have higher rates of protein synthesis and IGF-I generation than girls, given comparable doses of GH. In patients with a constitutional delay in growth and maturation, relative deficiencies in testosterone and lower IGF-I concentrations are associated with greater rates of total energy expenditure, suggesting that this relatively hormone-insufficient state is associated with a hypermetabolic state. Whether added nutritional supplements, alone or in combination with GH, could improve the growth pattern and final height of these children deserves further study. In conclusion, the metabolic effects of GH and testosterone are complex and they synergize in puberty. These hormones could be of use as protein-anabolic agents in selected catabolic conditions.
Single and Combined Effects of Growth Hormone and Testosterone in Healthy Older Men
Authors: Weltman Arthur , Veldhuis Johannes D.
Published: January 2007

The life expectancy of populations in the USA and Western European countries is increasing, but the prevalence of features of ageing, such as physical frailty and disability, increases in parallel, creating the challenge of maintaining good health during this longer life. Many physical features of ageing resemble those seen in men with growth hormone (GH) deficiency and/or organic androgen deficiency. In this article, we briefly review the effects of ageing on GH and testosterone release in males, along with data regarding the single or combined administration of GH and testosterone on outcome variables in ageing men. Although some studies suggest that GH, testosterone, or combination therapy may have utility when administered in elderly males, adequately powered, long-term trials with appropriate endpoints are needed. Until this information becomes available, we believe that GH and/or testosterone supplementation in healthy older adults should be limited to individuals in well-controlled research studies.
Magnetic Resonance Techniques for Assessment of Body Components
Authors: Schick Fritz , Machann Jürgen , Boss Andreas , Thamer Claus , Stefan Norbert , Fritsche Andreas
Published: January 2007

With the increasing interest in personal health, nutritional status and fitness, several methods of estimating body fat have been developed and used in clinical settings. Hormonal effects and changes in metabolic pathways during the development of diseases (e.g. type 2 diabetes mellitus) lead to specific changes in the volume fractions and distribution of fat-containing compartments in the body. Magnetic resonance (MR) has been proven to be a reliable and non-invasive tool for the assessment of fatty and lean tissue, with a high spatial resolution of approximately 1 mm. Modern MR systems with large receiver coil arrays and automatic positioning tables allow whole-body imaging in examination times of about 20 min. Special highly specific fat-selective imaging techniques provide total suppression of water signals and allow a sensitive visualization of fatty infiltration in ‘lean’ organs, such as liver or skeletal musculature. Whereas fat-selective imaging requires at least 1–2% of lipids in parenchymal tissue to provide signal intensity in the images above the noise level, volume-selective [1H]MR spectroscopy is even more sensitive. Volume fractions of lipids down to 0.1% can be quantitatively assessed using [1H]MR spectroscopy, and several portions of lipids (fatty septa vs. intramyocellular fat) can be distinguished in skeletal musculature.