bluuebunny/crossref_metadata_2025_split huggingface dataset:
An In Vivo Topoisomerase II Cleavage Site and a DNase I Hypersensitive Site Colocalize Near Exon 9 in the MLLBreakpoint Cluster Region
Authors: Strissel Pamela L. , Strick Reiner , Rowley Janet D. , Zeleznik-Le Nancy J. 
Published: October 2019

Abstract
The human myeloid-lymphoid leukemia gene, MLL (also calledALL-1, Htrx, or HRX ), maps to chromosomal band 11q23. MLL is involved in translocations that result in de novo acute lymphoblastic leukemia (ALL), acute myelogenous leukemia (AML), mixed lineage leukemia, and also in therapy AML (t-AML) and therapy ALL (t-ALL) resulting from treatment with DNA topoisomerase II (topo II) targeting drugs. MLL can recombine with more than 30 other chromosomal bands, of which 16 of the partner genes have been cloned. Breaks in MLL occur in an 8.3-kb breakpoint cluster region (BCR) encompassing exons 5 through 11. We recently demonstrated that 75% of de novo patient breakpoints in MLL mapped in the centromeric half of the BCR between two scaffold-associated regions (SAR), whereas 75% of the t-AML patient breakpoints mapped to the telomeric half of the BCR within a strong SAR. We have mapped additional structural elements in the BCR. An in vivo DNA topo II cleavage site (induced with several different drugs that target topo II) mapped near exon 9 in three leukemia cell lines. A strong DNase I hypersensitive site (HS) also mapped near exon 9 in four leukemia cell lines, including two in which MLL was rearranged [a t(6;11) and a t(9;11)], and in two lymphoblastoid cell lines with normalMLL. Two of the leukemia cell lines also showed an in vivo topo II cleavage site. Our results suggest that the chromatin structure of the MLL BCR may influence the location of DNA breaks in both de novo and therapy-related leukemias. We propose that topo II is enriched in the MLL telomeric SAR and that it cleaves the DNase I HS site after treatment with topo II inhibitors. These events may be involved in recombination associated with t-AML/t-ALL breakpoints mapping in the MLL SAR.
Development of a Model for Evaluating the Interaction Between Human Pre-B Acute Lymphoblastic Leukemic Cells and the Bone Marrow Stromal Cell Microenvironment
Authors: Shah Nisha , Oseth LeAnn , LeBien Tucker W. 
Published: October 2019

AbstractClonal expansion of B-cell precursor acute lymphoblastic leukemia (ALL) is potentially regulated by survival, growth, and death signals transduced by the bone marrow (BM) microenvironment. Using a human BM stromal cell culture that supports the growth of normal human B-cell precursors, we established a pre-B ALL cell line designated BLIN-2. BLIN-2 has a clonal rearrangement of the Ig heavy chain locus, a dic(9;20) chromosomal abnormality, and a bi-allelic deletion of thep16INK4a and p19ARF genes. The most interesting feature of BLIN-2 is an absolute dependence on adherent human BM stromal cells for sustained survival and growth. BLIN-2 cultured in the absence of BM stromal cells undergo apoptosis, and direct contact with viable BM stromal cells is essential for optimal growth. BLIN-2 cells also grow on vascular cell adhesion molecule-1 (VCAM-1)–negative human skin fibroblasts, making it unlikely that a very late antigen-4 (VLA-4)/VCAM-1 interaction is required for BLIN-2 growth. Western blot analysis of BLIN-2 cells cultured in the presence or absence of BM stromal cells demonstrates that contact of BLIN-2 with BM stromal cells induces hyperphosphorylation of Rb. In contrast, the pre-B ALL cell line BLIN-1, which has a bi-allelic deletion of p16INK4ap19ARF but does not require BM stromal cells for growth, does not undergo Rb phosphorylation after BM stromal cell contact. The BLIN-2 cell line will facilitate identification of ligand/receptor interactions at the B-cell precursor/BM stromal cell interface and may provide new insight into microenvironmental regulation of leukemic cell survival and growth.
Bcr-Abl Efficiently Induces a Myeloproliferative Disease and Production of Excess Interleukin-3 and Granulocyte-Macrophage Colony-Stimulating Factor in Mice: A Novel Model for Chronic Myelogenous Leukemia
Authors: Zhang Xiaowu , Ren Ruibao 
Published: October 2019

Abstract
The bcr-abl oncogene plays a critical role in causing chronic myelogenous leukemia (CML). Effective laboratory animal models of CML are needed to study the molecular mechanisms by which thebcr-abl oncogene acts in the disease progression of CML. We used a murine stem cell retroviral vector (MSCV) to transduce thebcr-abl/p210 oncogene into mouse bone marrow cells and found that expression of Bcr-Abl/p210 induced a myeloproliferative disorder that resembled the chronic phase of human CML in 100% of bone marrow transplanted mice in about 3 weeks. This CML-like disease was readily transplanted to secondary recipient mice. Multiple clones of infected cells were expanded in the primary recipients, but the leukemia was primarily monoclonal in the secondary recipient mice. Mutation analysis demonstrated that the protein tyrosine kinase activity of Bcr-Abl/p210 was essential for its leukemogenic potential in vivo. Interestingly, we found that the leukemic cells expressed excess interleukin-3 (IL-3) and granulocyte-macrophage colony-stimulating factor (GM-CSF) in the diseased mice. These studies demonstrate that expression of Bcr-Abl can induce a CML-like leukemia in mice much more efficiently and reproducibly than in previously reported mouse CML models, probably due to efficient expression in the correct target cell(s). Our first use of this model for analysis of the molecular mechanisms involved in CML raises the possibility that excess expression of hematopoietic growth factors such as IL-3 and GM-CSF may contribute to the clinical phenotype of CML.
Deregulated PAX-5 Transcription From a TranslocatedIgH Promoter in Marginal Zone Lymphoma
Authors: Morrison Aline M. , Jäger Ulrich , Chott Andreas , Schebesta Michael , Haas Oskar A. , Busslinger Meinrad 
Published: October 2019

AbstractThe PAX-5 gene codes for the transcription factor BSAP, which is expressed throughout B-cell development. Although loss-of-function mutation in the mouse showed an essential role forPax-5 in early B lymphopoiesis, gain-of-function mutations have implicated the human PAX-5 gene in the control of late B-cell differentiation. PAX-5 (on 9p13) has been involved together with the immunoglobulin heavy-chain (IgH) gene (on 14q32) in the recurring t(9;14)(p13;q32) translocation that is characteristic of small lymphocytic lymphoma with plasmacytoid differentiation. Here we have characterized a complex t(2;9;14)(p12;p13;q32) translocation present in a closely related non-Hodgkin’s lymphoma referred to as splenic marginal zone lymphoma (MZL). In this MZL-1 translocation, the two promoters of PAX-5 were replaced on the derivative chromosome 14 by an immunoglobulin switch Sμ promoter that was linked to the structural PAX-5 gene upstream of its translation initiation codon in exon 1B. Expression analyses confirmed thatPAX-5 transcription was upregulated due to efficient initiation at the Sμ promoter in the malignant B lymphocytes of patient MZL-1. For comparison we have analyzed PAX-5 expression in another B-cell lymphoma, KIS-1, indicating that transcription from the distalPAX-5 promoter was increased in this tumor in agreement with the previously characterized translocation of the immunoglobulin Eμ enhancer adjacent to PAX-5 exon 1A. In both lymphomas, the J-chain gene, which is thought to be under negative control by BSAP, was not expressed, whereas transcription of the putative target genep53 was unaffected by PAX-5 overexpression. Together these data indicate that the t(9;14)(p13;q32) translocation contributes to lymphoma formation as a regulatory mutation that leads to increasedPAX-5 expression in late B-cell differentiation due to promoter replacement or enhancer insertion.
Antigen-Induced Eosinophilic Lung Inflammation Develops in Mice Deficient in Chemokine Eotaxin
Authors: Yang Yi , Loy James , Ryseck Rolf-Peter , Carrasco Daniel , Bravo Rodrigo 
Published: October 2019

AbstractThe mechanisms that regulate the selective infiltration of eosinophils in certain allergic diseases are still poorly understood. The CC chemokine eotaxin is a potent chemoattractant, highly specific for eosinophils. Recent studies have implicated that eotaxin plays an important role in the recruitment of eosinophils in different inflammation processes. A number of other chemokines, cytokines, and chemoattractants also have chemotactic activities for eosinophils and some of them present high selectivity for eosinophils. To further study the role of eotaxin in inflammation, we generated mutant mice with the eotaxin gene disrupted and replaced by the Escherichia coliβ-galactosidase gene. These mice developed normally and had no histologic or hematopoietic abnormalities. Furthermore, our studies showed that the lack of eotaxin did not affect the recruitment of eosinophils in the inflammation models induced by Sephadex beads and thioglycollate, as well as in an experimental lung eosinophilia model induced by ovalbumin aerosol challenge, even at the onset of the inflammatory response. The replacement of the eotaxin gene by the β-galactosidase gene provided a useful marker to monitor the activity of the eotaxin promoter under normal conditions and after antigen challenges. Immunohistochemical staining suggested that endothelial cells were the major sources of eotaxin expression.
Minimal Residual Disease Status Before Allogeneic Bone Marrow Transplantation Is an Important Determinant of Successful Outcome for Children and Adolescents With Acute Lymphoblastic Leukemia
Authors: Knechtli Christopher J.C. , Goulden Nicholas J. , Hancock Jeremy P. , Grandage Victoria L.G. , Harris Emma L. , Garland Russell J. , Jones Claire G. , Rowbottom Anthony W. , Hunt Linda P. , Green Ann F. , Clarke Emer , Lankester Alan W. , Cornish Jacqueline M. , Pamphilon Derwood H. , Steward Colin G. , Oakhill Anthony 
Published: October 2019

Abstract
The efficacy of allografting in acute lymphoblastic leukemia (ALL) is heavily influenced by remission status at the time of transplant. Using polymerase chain reaction (PCR)-based minimal residual disease (MRD) analysis, we have investigated retrospectively the impact of submicroscopic leukemia on outcome in 64 patients receiving allogeneic bone marrow transplantation (BMT) for childhood ALL. Remission BM specimens were taken 6 to 81 days (median, 23) before transplant. All patients received similar conditioning therapy; 50 received grafts from unrelated donors and 14 from related donors. Nineteen patients were transplanted in first complete remission (CR1) and 45 in second or subsequent CR. MRD was analyzed by PCR of Ig or T-cell receptor δ or γ rearrangements, electrophoresis, and allele-specific oligoprobing. Samples were rated high-level positive (clonal band evident after electrophoresis; sensitivity 10−2 to 10−3), low-level positive (MRD detected only after oligoprobing; sensitivity 10−3 to 10−5), or negative. Excluding 8 patients transplanted in CR2 for isolated extramedullary relapse (all MRD−), MRD was detected at high level in 12 patients, low level in 11, and was undetectable in 33. Two-year event-free survival for these groups was 0%, 36%, and 73%, respectively (P &lt; .001). Follow-up in patients remaining in continuing remission is 20 to 96 months (median, 35). These results suggest that MRD analysis could be used routinely in this setting. This would allow identification of patients with resistant leukemia (who may benefit from innovative BMT protocols) and of those with more responsive disease (who may be candidates for randomized trials of BMT versus modern intensive relapse chemotherapy).
Functional Analysis of Mature Hematopoietic Cells From Mice Lacking the βc Chain of the Granulocyte-Macrophage Colony-Stimulating Factor Receptor
Authors: Scott C.L. , Hughes D.A. , Cary D. , Nicola N.A. , Begley C.G. , Robb L. 
Published: October 2019

AbstractMice with a null mutation of the βc chain of the granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-3 (IL-3), and IL-5 receptors (βc-null mice) develop an alveolar proteinosis-like lung disease. The pathogenesis of this disease is uncertain and, although a defect in alveolar macrophage function has been postulated, no previous analysis of mature hematopoietic cells in mice with alveolar proteinosis has been reported. Therefore, we undertook a functional analysis of the mature hematopoietic cell compartment in βc-null mice. In addition, we reexamined the roles of the GM-CSF receptor  chain and the βc chain in signaling by GM-CSF. Neutrophils and macrophages from βc-null mice were capable of normal survival and phagocytosis in the absence of stimulus and of similar levels of nitric oxide production in response to interferon-γ and lipopolysaccharide. GM-CSF–mediated augmentation of survival, phagocytosis, and hydrogen-ion production were absent in neutrophils from βc-null mice. Interestingly, we were unable to show any ability of the GM-CSF receptor -chain alone to mediate glucose transport in these cells. In keeping with the βc-null mice lung pathology, examination of lavage fluid from the lungs of βc-null mice showed increased cellularity. This was caused by an increase in the number of lymphocytes, neutrophils, and macrophages. Large foamy cells in the lavage fluid from βc-null mice were identified as macrophages using immunohistochemistry. Functional analysis showed that these βc-null alveolar macrophages were capable of phagocytosis but uptake of colloidal carbon and cellular adhesion were reduced. In summary, mature hematopoietic cells with a null mutation of the βc receptor were unable to perform GM-CSF–mediated hematopoietic cell functions including glucose transport, but responded normally to a range of other ligands.
Role of Tissue Factor in Adhesion of Mononuclear Phagocytes to and Trafficking Through Endothelium In Vitro
Authors: Randolph Gwendalyn J. , Luther Thomas , Albrecht Sybille , Magdolen Viktor , Muller William A. 
Published: October 2019

AbstractAn in vitro model consisting of endothelium grown on collagen was used to investigate how mononuclear phagocytes traverse endothelium in the basal-to-apical direction (reverse transmigration), a process that mimics their migration across vascular and/or lymphatic endothelium during atherosclerosis and resolution of inflammation, respectively. Monoclonal antibody (MoAb) VIC7 against tissue factor (TF) inhibited reverse transmigration by 77%. Recombinant tissue factor fragments containing at least six amino acids C-terminal to residue 202 also strongly inhibited reverse transmigration. TF was absent on resting monocytes but was induced on these cells after initial apical-to-basal transendothelial migration. Two additional observations suggest that TF is involved in adhesion between mononuclear phagocytes and endothelium: (1) when monocytes were incubated with lipopolysaccharide (LPS) to stimulate expression of TF before they were added to endothelium, VIC7 or soluble TF modestly inhibited their adhesion to the apical endothelial surface, each by about 35%; and (2) endothelial cells specifically bound to surfaces coated with TF fragments containing amino acids 202-219. This binding was blocked by anti-TF MoAb, suggesting that endothelial cells bear a receptor for TF. These data suggest that mononuclear phagocytes use TF, perhaps as an adhesive protein, to exit sites of inflammation.
R to Q Amino Acid Substitution in the GFFKR Sequence of the Cytoplasmic Domain of the Integrin IIb Subunit in a Patient With a Glanzmann’s Thrombasthenia-Like Syndrome
Authors: Peyruchaud O. , Nurden A.T. , Milet S. , Macchi L. , Pannochia A. , Bray P.F. , Kieffer N. , Bourre F. 
Published: October 2019

AbstractThe integrin IIbβ3 mediates platelet aggregation through its fibrinogen and adhesive protein-binding properties. Particular interest concerns the role of the cytoplasmic domains of IIb and β3. We now report the molecular analysis of IIbβ3 from a patient with a Glanzmann’s thrombasthenia-like syndrome for whom the principal characteristics are an approximate 50% total platelet content of IIbβ3 but with a much lower proportion in the surface pool (Hardisty et al, Blood 80:696, 1992). Polymerase chain reaction (PCR) single-strand conformational polymorphism and DNA sequencing showed a heterozygous mutation giving rise to amino acid substitution R995 to Q in the GFFKR sequence of the cytoplasmic domain of IIb. Reverse transcriptase-PCR and polymorphism analysis only detected mRNA for the mutated allele of the IIb gene and a single allele of the β3 gene in his platelets, suggesting other unidentified defects. Site-directed mutagenesis followed by transient expression of the mutated IIb together with wild-type β3 in Cos-7 cells resulted in a markedly decreased expression of the complex at the cell surface when compared with cells transfected with wild-type IIb and β3. Flow cytometry with PAC-1 and a stable Chinese hamster ovary–transfected cell line showed that the mutated receptor was not locked into a high activation state, although it became so in the presence of the activating antibody, anti-LIBS6. This is the first reported natural mutation in the highly conserved GFFKR sequence of the IIb cytoplasmic domain.
Identification of Peptides, Selected by Phage Display Technology, That Inhibit von Willebrand Factor Binding to Collagen
Authors: Depraetere H. , Viaene A. , Deroo S. , Vauterin S. , Deckmyn H. 
Published: October 2019

AbstractA repeated selection of phages from a cyclic hexapeptide phage display library resulted in an enrichment of phages that bound to the monoclonal antibody (MoAb) 82D6A3 (an anti–von Willebrand Factor [vWF] antibody that inhibits binding of vWF to collagen). Two clones were selected that bound both to MoAb 82D6A3 and to rat tail collagen type I in a specific and dose-dependent manner. The two phage clones were further used in a two-direction competition experiment with vWF. vWF was able to displace phages from collagen in a dose-dependent manner with an IC50 of 35 μg/mL and phages were able to inhibit vWF binding to collagen. With the use of specific primers, the sequence of the cysteine-flanked hexapeptide inserts could be deduced. The two phage clones carried an almost identical sequence, CVWLWEQC and CVWLWENC, with a substitution of an N for a Q at position 6 of the hexapeptide. Sequence comparison with the known vWF sequence showed the presence of a comparable sequence at position 1129-1136 (VWTLPDQC), located between the collagen-binding A3-domain and the D4-domain. The two cyclic peptides, the putative corresponding vWF peptide, and a peptide with a scrambled cyclic sequence were synthesized. The two cyclic peptides inhibited vWF binding to rat tail collagen type I in a dose-dependent manner, whereas the linear vWF peptide and the scrambled cyclic peptide were inactive. For half maximal inhibition, 100 ± 12.7 μmol/L and 34.8 ± 8.59 μmol/L (mean ± SEM, n = 3) of the N- and the Q-peptide, respectively, were needed. The two cyclic peptides were also able to inhibit vWF binding to calfskin and human collagen type I, but effective concentrations were some 5 to 10 times higher.
Modulation of Granulocyte-Macrophage Colony-Stimulating Factor Gene Expression by a Tumor Necrosis Factor  Specific Ribozyme in Juvenile Myelomonocytic Leukemic Cells
Authors: Iversen Per Ole , Sioud Mouldy 
Published: October 2019

AbstractThe human cytokines tumor necrosis factor  (TNF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) both promote growth and survival of malignant cells from children with juvenile myelomonocytic leukemia (JMML). It has been postulated that TNF stimulates GM-CSF gene expression in an autocrine manner. We found here that the specific inhibition of TNF gene expression by a catalytic RNA molecule (ribozyme) also downregulated the expression of GM-CSF in JMML cells. GM-CSF protein, GM-CSF–dependent colony formation, and viability of JMML cells were reduced. The observed effect was specific, because synthesis of interleukin-1β, another cytokine produced by JMML cells, was not affected by the ribozyme treatment. The stimulatory effect of TNF on GM-CSF gene expression in JMML cells probably takes place at the transcription level, because the ribozyme treatment decreased GM-CSF mRNA. No apparent toxicity of the ribozyme was detected in normal bone marrow progenitor cells. Thus, the inhibition of TNF gene expression in JMML cells by ribozymes may be a novel therapeutic approach for this disorder.
Flow Cytometric Diagnosis of the Cell Lineage and Developmental Stage of Acute Lymphoblastic Leukemia by Novel Monoclonal Antibodies Specific to Human Pre–B-Cell Receptor
Authors: Tsuganezawa Keiko , Kiyokawa Nobutaka , Matsuo Yoshinobu , Kitamura Fujiko , Toyama-Sorimachi Noriko , Kuida Keisuke , Fujimoto Junichiro , Karasuyama Hajime 
Published: October 2019

AbstractThree novel monoclonal antibodies (MoAbs) have been established that recognize distinct epitopes of a human pre–B-cell receptor (pre-BCR) composed of a μ heavy (μH) chain and a λ5/VpreB surrogate light (SL) chain. HSL11 reacts with λ5 whereas HSL96 reacts with VpreB. Intriguingly, HSL2 does not bind to each component of the pre-BCR but does bind to the completely assembled pre-BCR complex. Flow cytometric analyses with cytoplasmic staining of a panel of human cell lines showed that HSL11 and HSL96 specifically stained cell lines derived from the pro–B and pre–B-cell stages of B-cell development. In contrast, HSL2 stained exclusively cell lines derived from the pre–B-cell stage. These results prompted us to explore the possibility of clinical application of these MoAbs for the determination of the cell lineage and developmental stage of acute lymphoblastic leukemia (ALL). Whereas none of mature B-lineage ALLs (B-ALLs), T-lineage ALLs (T-ALLs), and acute myeloid leukemias analyzed were stained in the cytoplasm with these three MoAbs, the vast majority of non–B- and non–T-ALLs (53 out of 56 cases) were found positive for either λ5, Vpre-B, or both in their cytoplasm. Among these 53 cytoplasmic SL chain-positive ALLs, 19 cases were also positive for cytoplasmic μH chain, indicative of pre–B-cell origin. Interestingly, 6 out of these 19 pre–B-ALL cases were found negative for cytoplasmic staining with HSL2. From these results, we propose a novel classification of B-ALL in which five subtypes are defined on the basis of the differential expression of SL chain, μH chain, pre-BCR, and light chain along the B-cell development.
Progressive and Persistent Downregulation of Surface CXCR4 in CD4+ T Cells Infected With Human Herpesvirus 7
Authors: Secchiero Paola , Zella Davide , Barabitskaja Oxana , Reitz Marvin S. , Capitani Silvano , Gallo Robert C. , Zauli Giorgio 
Published: October 2019

AbstractWe have previously shown that infection of CD4+ T lymphocytes with the T-lymphotropic human herpesvirus 7 (HHV-7) downregulates surface CD4, which represents the high-affinity receptor for HHV-7. In this study, we report that HHV-7 infection also causes a progressive loss of the surface CXC-chemokine receptor 4 (CXCR4) in CD4+ T cells, accompanied by a reduced intracellular Ca2+ flux and chemotaxis in response to stromal cell-derived factor-1 (SDF-1), the specific CXCR4 ligand. Moreover, CXCR4 is downregulated from the surface of HHV-7–infected T cells independently of CD4. Because intracellular CXCR4 antigen and mRNA levels are unaffected in productively HHV-7–infected cells, the downregulation of CXCR4 apparently does not involve a transcritional block. Since CXCR4 functions in association with CD4 to permit entry of several human immunodeficiency virus (HIV) isolates, the potential of HHV-7 to persistently downregulate the surface expression of CXCR4 may provide novel strategies for limiting HIV infection.