bluuebunny/crossref_metadata_2025_split huggingface dataset:
Altered Expression and Activity of Topoisomerases During All-Trans Retinoic Acid-Induced Differentiation of HL-60 Cells
Authors: Aoyama Masako , Grabowski Dale R. , Isaacs Richard J. , Krivacic Kim A. , Rybicki Lisa A. , Bukowski Ronald M. , Ganapathi Mahrukh K. , Hickson Ian D. , Ganapathi Ram 
Published: October 2019

AbstractRegulation of topoisomerase II (TOPO II) isozymes  and β is influenced by the growth and transformation state of cells. Using HL-60 cells induced to differentiate by all-trans retinoic acid (RA), we have investigated the expression and regulation of TOPO II isozymes as well as the levels of topoisomerase I (TOPO I). During RA-induced differentiation of human leukemia HL-60 cells, levels of TOPO I remained unchanged, whereas the levels and phosphorylation of TOPO II and TOPO IIβ proteins were increased twofold to fourfold and fourfold to eightfold, respectively. The elevation of TOPO II ( and β) protein levels and phosphorylation was apparent at 48 hours of treatment with RA and persisted through 96 hours. The increased level of TOPO IIβ protein was also detected in differentiated cells subsequently cultured for 96 hours in RA-free medium. Pulse chase experiments in cells labeled with 35S-methionine showed that the rate of degradation of TOPO IIβ protein in control cells was about twofold faster than that in the differentiated RA-treated cells. The level of decatenation activity of kDNA was comparable in nuclear extracts from control or RA-treated cells. Whereas etoposide (1 to 10 μmol/L) -induced DNA cleavage was not significantly different, apoptosis was significantly lower (P = .012) in RA-treated versus control cells after exposure to 10 μmol/L etoposide. Consistent with unaltered levels of TOPO I, camptothecin (CPT) -induced DNA cleavage was similar in control or RA-treated cells. However, apoptosis after exposure to 1 to 10 μmol/L CPT was significantly lower (P = .003 to P &lt; .001) in RA-treated versus control cells. Results suggest that TOPO IIβ protein levels are posttranscriptionally regulated and that degradation of TOPO IIβ is decreased during RA-induced differentiation. Furthermore, whereas the total level of TOPO II ( + β) is increased with RA, the level of TOPO II catalytic activity and etoposide-stabilized DNA cleavage activity remains unaltered. Thus, TOPO IIβ may have a specific role in transcription of genes involved in differentiation with RA treatment.© 1998 by The American Society of Hematology.
CBFA2(AML1) Translocations With Novel Partner Chromosomes in Myeloid Leukemias: Association With Prior Therapy
Authors: Roulston Diane , Espinosa Rafael , Nucifora Giuseppina , Larson Richard A. , Le Beau Michelle M. , Rowley Janet D. 
Published: October 2019

Abstract
CBFA2(AML1) has emerged as a gene critical in hematopoiesis; its protein product forms the DNA-binding subunit of the heterodimeric core-binding factor (CBF) that binds to the transcriptional regulatory regions of genes, some of which are active specifically in hematopoiesis. CBFA2 forms a fusion gene with ETO andMDS1/EVI1 in translocations in myeloid leukemia and withETV6(TEL) in the t(12;21) common in childhood pre-B acute lymphoblastic leukemia. We have analyzed samples from 30 leukemia patients who had chromosome rearrangements involving 21q22 by using fluorescence in situ hybridization (FISH). Our analysis showed that 7 of them involved CBFA2 and new translocation partners. Two patients had a t(17;21)(q11.2;q22), whereas the other 5 had translocations involving 1p36, 5q13, 12q24, 14q22, or 15q22. Five of these novel breakpoints in CBFA2 occurred in intron 6; this same intron is involved in the t(3;21). One breakpoint mapped to the t(8;21) breakpoint region in intron 5, and 1 mapped 5′ to that region. All 7 CBFA2 rearrangements resulted from balanced translocations. All 7 patients had myeloid disorders (acute myeloid leukemia or myelodysplastic syndrome); 2 were de novo and 5 had treatment histories that included topoisomerase II targeting agents. The association of therapy-related disorders with translocations involving CBFA2 was significant by Fisher’s exact test (P &lt; .003). These results provide further evidence that this region of CBFA2 is susceptible to breakage in cells exposed to topoisomerase II inhibitors.
© 1998 by The American Society of Hematology.
PTEN Gene Alterations in Lymphoid Neoplasms
Authors: Sakai Akira , Thieblemont Catherine , Wellmann Axel , Jaffe Elaine S. , Raffeld Mark 
Published: October 2019

Abstract
Recently, a novel phosphatase designated PTEN/MMAC1/TEP1 and located on chromosome 10q23.3 has been implicated as a new tumor suppressor gene in human cancer. Allelic loss and mutation of this gene has been reported in epithelial derived tumors, including breast cancer and prostate cancer, and in glioblastoma multiforme. The present study was designed to evaluate the potential involvement of PTEN in the pathogenesis of lymphoid neoplasms. We analyzed 27 hematopoietic cell lines (representing a variety of lymphoid lineages), 65 primary lymphoid tumors (including 24 lymphoblastic leukemia/lymphoma [LBL], 30 large B-cell lymphoma [LBCL], 7 Burkitt’s lymphoma [BL], and 4 anaplastic large cell lymphoma [ALCL]), and 25 nonmalignant lymph node controls. Gene deletion and gross rearrangement were evaluated using Southern blot analysis, and mutations were studied by polymerase chain reaction (PCR)-single-strand conformation polymorphism (SSCP) (PCR-SSCP) and sequencing. Six of 27 cell lines (22.2%) and 3 of 65 primary lymphomas (4.6%) contained alterations of this gene. A large homozygous deletion spanning exons 2 through 5 was detected in one LBL cell line, and two insertions potentially resulting in premature termination, were detected in a second LBL cell line. Nonconservative nucleotide variations were found in two other cell lines (one LBCL and one BL) and in one primary case of LBCL. In addition, two other cell lines (one BL and one myeloma) and two primary lymphomas, both LBCL, contained small deletions within intron 7. These deletions mapped to a poly-T–rich tract just 5′ to the intron 7/exon 8 spice site. Their significance is unclear, as they may represent polymorphisms. Overall, our results suggest that abnormalities of the PTEN gene can contribute to pathogenesis in a small percentage of malignant lymphomas.
This is a US government work. There are no restrictions on its use.
Comparison of Expression of Human Globin Genes Transferred Into Mouse Erythroleukemia Cells and in Transgenic Mice
Authors: Skarpidi E. , Vassilopoulos G. , Stamatoyannopoulos G. , Li Q. 
Published: October 2019

Abstract
To examine whether transfer of γ globin genes into mouse erythroleukemia cells can be used for the analysis of regulatory elements of γ globin gene promoter, Aγ gene constructs carrying promoter truncations that have been previously analyzed in transgenic mice were used for production of stably transfected mouse erythroleukemia (MEL) cell clones and pools. We found that constructs, which contain a microlocus control region (μLCR) that efficiently protects globin gene expression from the effects of the position of integration in transgenic mice, display position-dependent globin gene expression in MEL cell clones. Aγ globin gene expression among MEL cell clones carrying the μLCR(−201)Aγ and μLCR(−382)Aγ gene constructs ranged 15.5-fold and 17.6-fold, respectively, and there was no correlation between theAγ mRNA levels and the copies of the transgene (r= .28, P = .18). There was significant variation in per copy Aγ globin gene expression among MEL cell pools composed of 10 clones, but not among pools composed of 50 clones, indicating that position effects are averaged in pools composed by large numbers of clones. The overall pattern of Aγ globin gene expression in MEL cell pools resembled that observed in transgenic mice indicating that MEL cell transfections can be used in the study ofcis elements controlling γ globin gene expression. MEL cell transfections, however, are not appropriate for investigation of cis elements, which either sensitize or protect the globin transgenes from position effects.
© 1998 by The American Society of Hematology.
Light Chain Shifting: Identification of a Human Plasma Cell Line Actively Undergoing Light Chain Replacement
Authors: Tachibana Hirofumi , Haruta Hirotaka , Yamada Koji 
Published: October 2019

AbstractWe identified an antibody-secreting human B-cell line (HTD8), which actively replaces the production of the original λ light chain with a new λ chain (light chain shifting) at a high rate. Loss of the original rearranged λ light chain occurs by significantly reducing the amount of transcript expressed. Expression of the new λ chain, which replaces the original λ chain, occurs by rearranging new VJ segments on a previously excluded allele. V λ gene usage of these new rearrangements are biased toward Vλ4, Vλ6, and Vλ10 families, which are known to be the least frequently used. In striking contrast to the plasma cell phenotype, recombination activating genes, RAG-1 and RAG-2, were expressed in the HTD8 cells and were shown to be necessary, but insufficient for inducing expression of the new λ chain. These results suggest that human plasma cells have the potential to actively undergo light chain replacement.
Insulin-Like Growth Factor-1 Acts as a Chemoattractant Factor for 5T2 Multiple Myeloma Cells
Authors: Vanderkerken Karin , Asosingh Kewal , Braet Filip , Van Riet Ivan , Van Camp Ben 
Published: October 2019

AbstractThe chemotactic and growth-stimulatory effect of insulin-like growth factor 1 (IGF-1) was investigated in the experimental mouse 5T2 multiple myeloma (MM) model. Chemotaxis was analyzed by classical checkerboard analysis. Bone marrow fibroblasts–conditioned medium exhibited a chemotactic effect on 5T2 MM cells that could be neutralized by adding a blocking antibody to IGF-1. On the other hand, exogenously added IGF-1 also had a chemotactic effect on the 5T2 MM cells. Moreover, in vitro analysis demonstrated that transmigrated 5T2 MM cells have a higher expression of IGF-1 receptor, both in bone marrow–conditioned medium and in IGF-1–induced chemotaxis, in comparison to cells before migration. When analyzed in vivo, 18 hours after injection of the heterogeneous 5T2 MM population, 5T2 MM cells present in the bone marrow show a higher expression of the IGF-1 receptor than their counterparts before injection. When the proliferative effect of IGF-1 was analyzed, no stimulation was observed, which is in contrast to the influence of bone marrow–conditioned medium and interleukin-6. Our results suggest a causal relationship between the presence of IGF-1 in the bone marrow and the chemotaxis of MM cells to and their subsequent presence in the bone marrow.
Functional Differentiation Signals Mediated by Distinct Regions of the Cytoplasmic Domain of the Granulocyte Colony-Stimulating Factor Receptor
Authors: Koay Debbie C. , Sartorelli Alan C. 
Published: October 2019

AbstractGranulocyte colony-stimulating factor receptor (G-CSFR) regulates the proliferation and differentiation of neutrophilic progenitor cells through interaction with its cytokine. Exposure of WEHI-3B D+ myelomonocytic leukemia and myeloid LGM-1 cells overexpressing the G-CSFR to G-CSF resulted in induction of differentiation as measured by (1) the ability to reduce nitroblue tetrazolium (NBT), (2) the expression of Mac-I antigen, and (3) the expression of FcγII/III receptor. Mutational analyses indicated that distinct regions of the cytoplasmic domain were critical for efficient induction of each functional marker. The membrane proximal region containing homology sequences of boxes 1 and 2 was important for the activation of all three functional markers of mature neutrophils. Induction of the capacities to express Mac-I antigen or FcγII/III receptor also required additional sequences in the membrane proximal region between amino acids 70 and 100 and may be dependent on the phosphorylation of Tyr703. The findings suggest that distinct sequences within the amino-terminal region of the cytoplasmic domain of the receptor are sufficient to induce these functional markers of differentiation, and receptor tyrosine phosphorylation may be necessary.
Horizontal Transfer of DNA by the Uptake of Apoptotic Bodies
Authors: Holmgren Lars , Szeles Anna , Rajnavölgyi Eva , Folkman Judah , Klein Georg , Ernberg Ingemar , Falk Kerstin I. 
Published: October 2019

AbstractIn this study we have raised the question of whether DNA can be transferred from one cell to another by phagocytosis of apoptotic bodies. We have used integrated copies of the Epstein-Barr virus (EBV) as a marker to follow the fate and expression pattern of apoptotic DNA in the phagocytotic host. Apoptosis was induced in EBV-carrying cell lines by irradiation before cultivation with either human fibroblasts, macrophages, or bovine aortic endothelial cells. Analysis of the expression pattern of EBV-encoded genes was performed by immunofluorescent staining as well as in situ hybridization. Cocultivation of apoptotic bodies from lymphoid cell lines containing integrated but not episomal copies of EBV resulted in expression of the EBV-encoded genes EBER and EBNA1 in the recipient cells at a high frequency. Fluorescence in situ hybridization analysis showed uptake of human chromatin as well as integrated EBV-DNA into the nuclei of bovine aortic endothelial cells. These data show that DNA may be rescued and reused from apoptotic bodies by somatic cells. In addition, our findings suggest that apoptotic bodies derived from EBV-carrying B lymphocytes may serve as the source of viral transfer to cells that lack receptors for the EBV virus in vivo.
Human Immunoglobulin A Receptor (FcRI, CD89) Function in Transgenic Mice Requires Both FcR γ Chain and CR3 (CD11b/CD18)
Authors: van Egmond Marjolein , van Vuuren A.J. Hanneke , Morton H. Craig , van Spriel Annemiek B. , Shen Li , Hofhuis Frans M.A. , Saito Takashi , Mayadas Tanya N. , Verbeek J. Sjef , van de Winkel Jan G.J. 
Published: October 2019

AbstractEven though more immunoglobulin A (IgA) is produced in humans than all other isotypes combined, relatively little is known about receptors that bind the Fc part of IgA. The myeloid IgA receptor, FcRI (CD89), triggers various effector functions in vitro, but its in vivo role remains unclear. Here, a transgenic mouse model is described in which FcRI is expressed under its own regulatory sequences. Receptor expression and regulation by cytokines was comparable to the human situation and hFcRI can trigger phagocytosis and lysis of tumor cells. To analyze the contribution of the FcR γ chain or the β2 integrin CR3 (CD11b/CD18) in FcRI biological function, FcRI transgenic mice were crossed with either FcR γ chain −/− or CR3 −/− mice. In contrast to in vitro data, FcR γ chain was essential for surface expression of hFcRI in vivo. Functional studies in hFcRI/ γ−/−mice were, therefore, limited. In vitro studies showed FcR γ chain to be necessary for phagocytosis. Neither hFcRI expression nor phagocytosis, triggered via hFcRI, were influenced by CR3. Remarkably, the capacity to lyse tumor targets was ablated in hFcRI transgenic/ CR3−/− mice, although binding of neutrophils to tumor cells was intact. This shows a previously unrecognized importance of CR3 for hFcRI-mediated antibody-dependent cellular cytotoxicity (ADCC).
Enforced Expression of the GATA-2 Transcription Factor Blocks Normal Hematopoiesis
Authors: Persons Derek A. , Allay James A. , Allay Esther R. , Ashmun Richard A. , Orlic Donald , Jane Stephen M. , Cunningham John M. , Nienhuis Arthur W. 
Published: October 2019

AbstractThe zinc finger transcription factor GATA-2 is highly expressed in immature hematopoietic cells and declines with blood cell maturation. To investigate its role in normal adult hematopoiesis, a bicistronic retroviral vector encoding GATA-2 and the green fluorescent protein (GFP) was used to maintain the high levels of GATA-2 that are normally present in primitive hematopoietic cells. Coexpression of the GFP marker facilitated identification and quantitation of vector-expressing cells. Bone marrow cells transduced with the GATA-2 vector expressed GFP as judged by flow cytometry and GATA-2 as assessed by immunoblot analysis. A 50% to 80% reduction in hematopoietic progenitor-derived colony formation was observed with GATA-2/GFP-transduced marrow, compared with marrow transduced with a GFP-containing vector lacking the GATA-2 cDNA. Culture of purified populations of GATA-2/GFP-expressing and nonexpressing cells confirmed a specific ablation of the colony-forming ability of GATA-2/GFP-expressing progenitor cells. Similarly, loss of spleen colony-forming ability was observed for GATA-2/GFP-expressing bone marrow cells. Despite enforced GATA-2 expression, marrow cells remained viable and were negative in assays to evaluate apoptosis. Although efficient transduction of primitive Sca-1+Lin- cells was observed with the GATA-2/GFP vector, GATA-2/GFP-expressing stem cells failed to substantially contribute to the multilineage hematopoietic reconstitution of transplanted mice. Additionally, mice transplanted with purified, GATA-2/GFP-expressing cells showed post-transplant cytopenias and decreased numbers of total and gene-modified bone marrow Sca-1+ Lin−cells. Although Sca-1+ Lin− bone marrow cells expressing the GATA-2/GFP vector were detected after transplantation, no appreciable expansion in their numbers occurred. In contrast, control GFP-expressing Sca-1+Lin− cells expanded at least 40-fold after transplantation. Thus, enforced expression of GATA-2 in pluripotent hematopoietic cells blocked both their amplification and differentiation. There appears to be a critical dose-dependent effect of GATA-2 on blood cell differentiation in that downregulation of GATA-2 expression is necessary for stem cells to contribute to hematopoiesis in vivo.
Neutrophilic Cell Production by Combination of Stem Cell Factor and Thrombopoietin From CD34+ Cord Blood Cells in Long-Term Serum-Deprived Liquid Culture
Authors: Sawai Nobukuni , Koike Kenichi , Ito Susumu , Mwamtemi Hadija Hemed , Kurokawa Yumi , Kinoshita Tatsuya , Sakashita Kazuo , Higuchi Tsukasa , Takeuchi Kouichi , Shiohara Masaaki , Miyazaki Hiroshi , Kato Takashi , Komiyama Atsushi 
Published: October 2019

Abstract
In the present study, we investigated the effects of stem cell factor (SCF) and/or thrombopoietin (TPO) on the cell production by cord blood CD34+ cells using a serum-deprived liquid culture system. Although SCF alone supported a modest production of neutrophilic cells and a remarkable generation of mast cells, the addition of TPO to the culture containing SCF caused an apparent generation of neutrophilic cells, identified by immunocytochemical staining and flow cytometric analysis. The significant production of neutrophilic cells by SCF and TPO was persistently observed from 2 weeks to 2 to 3 months of culture. The interaction between SCF and TPO on the neutrophilic cell generation was greater than the combined effects of SCF with granulocyte colony-stimulating factor (G-CSF) or granulocyte-macrophage colony-stimulating factor (GM-CSF). The addition of neutralizing antibody against G-CSF or GM-CSF did not influence the SCF + TPO-dependent neutrophilic cell production. A single-cell culture study showed that not only CD34+CD38+ c-kit+ cells but also CD34+CD38−c-kit+ cells were responsible for the neutrophilic cell generation. In clonal cell cultures, GM progenitors as well as erythroid progenitors and multipotential progenitors expanded in the cultures supplemented with SCF and TPO. The neutrophilic cells grown by SCF + TPO were at myeloblast to band cell stages, and scarcely matured to segmented neutrophils. In addition, the cells generated by SCF + TPO were stained with monoclonal antibodies against myeloperoxidase, elastase, lactoferrin, and CD11b, but they had negligible levels of alkaline phosphatase (ALP) and CD35. The replating of the CD34−c-kit−/low CD15+ cells grown by SCF + TPO into a culture containing SCF + G-CSF permitted both the terminal maturation into segmented cells and the appearance of ALP and CD35. These results indicate the existence of a G-CSF/GM-CSF–independent system of neutrophilic cell production.
The Activity of the CCAAT-box Binding Factor NF-Y Is Modulated Through the Regulated Expression of Its A Subunit During Monocyte to Macrophage Differentiation: Regulation of Tissue-Specific Genes Through a Ubiquitous Transcription Factor
Authors: Marziali Giovanna , Perrotti Edvige , Ilari Ramona , Coccia Eliana M. , Mantovani Roberto , Testa Ugo , Battistini Angela 
Published: October 2019

AbstractIn this study, we analyzed the regulation of NF-Y expression during human monocyte to macrophage maturation. NF-Y is a ubiquitous and evolutionarily conserved transcription factor that binds specifically to the CCAAT motif present in the 5′ promoter region of a wide variety of genes. We show here that in circulating monocytes, NF-Y binding activity is not detected on the CCAAT motif present in the promoters of genes such as major histocompatibility complex (MHC) class II, gp91-phox, mig, and fibronectin, whereas during macrophage differentiation, a progressive increase in NF-Y binding activity is observed on these promoters. Analysis of NF-Y subunit expression indicates that the absence of NF-Y activity in circulating monocytes is caused by a lack of the A subunit. Furthermore, addition of the recombinant NF-YA subunit restores NF-Y binding. We show that the lack of NF-YA protein is due to posttranscriptional regulation and not to a specific proteolytic activity. In fact, NF-YA mRNA is present at the same level at all days of monocyte cultivation, whereas the protein is absent in freshly isolated monocytes but is progressively synthesized during the maturation process. We thus conclude that the NF-YA subunit plays a relevant role in activating transcription of genes highly expressed in mature monocytes. In line with this conclusion, we show that the cut/CDP protein, a transcriptional repressor that inhibits gpc91-phox gene expression by preventing NF-Y binding to the CAAT box, is absent in monocytes.
Synergistic Activation of Mitogen-Activated Protein Kinase by Cyclic AMP and Myeloid Growth Factors Opposes Cyclic AMP’s Growth-Inhibitory Effects
Authors: Lee Angel Wai-mun 
Published: October 2019

AbstractColony-stimulating factors (CSFs) promote the proliferation, differentiation, commitment, and survival of myeloid progenitors, whereas cyclic AMP (cAMP)-mediated signals frequently induce their growth arrest and apoptosis. The ERK/mitogen-activated protein kinase (MAPK) pathway is a target for both CSFs and cAMP. We investigated how costimulation by cAMP and colony-stimulating factor-1 (CSF-1) or interleukin-3 (IL-3) modulates MAPK in the myeloid progenitor cell line, 32D. cAMP dramatically increased ERK activity in the presence of CSF-1 or IL-3. IL-3 also synergized with cAMP to activate ERK in another myeloid cell line, FDC-P1. The increase in ERK activity was transmitted to a downstream target, p90rsk. cAMP treatment of 32D cells transfected with oncogenic Ras was found to recapitulate the superactivation of ERK seen with cAMP and CSF-1 or IL-3. ERK activation in the presence of cAMP did not appear to involve any of the Raf isoforms and was blocked by expression of dominant-negative MEK1 or treatment with a MEK inhibitor, PD98059. Although cAMP had an overall inhibitory effect on CSF-1–mediated proliferation and survival, the inhibition was markedly increased if ERK activation was blocked by PD98059. These findings suggest that upregulation of the ERK pathway is one mechanism induced by CSF-1 and IL-3 to protect myeloid progenitors from the growth-suppressive and apoptosis-inducing effects of cAMP elevations.