bluuebunny/crossref_metadata_2025_split huggingface dataset:
G-CSF Potently Suppresses Osteoblast Activity in the Bone Marrow.
Authors: Christopher Matthew J. , Liu Fulu , Short Brenton , Simmons Paul J. , Winkler Ingrid , Levesque Jean-Pierre , Link Daniel C. 
Published: April 2020

Abstract
There is accumulating evidence that interaction of stromal cell derived factor-1 (SDF-1/CXCL12) with its cognate receptor, CXCR4, generates signals that regulate hematopoietic progenitor cell (HPC) trafficking in the bone marrow. During G-CSF induced HPC mobilization, SDF-1 protein expression in the bone marrow decreases, thereby attenuating CXCR4 signaling. We recently reported that G-CSF treatment induced a decrease in bone marrow SDF-1 mRNA that closely mirrored the fall in SDF-1 protein, suggesting that G-CSF targets one or more SDF-1 producing cell population in the bone marrow. However, the identity of cell populations in the bone marrow that express SDF-1 is controversial. In the present study, we address this issue by sorting cells into mature hematopoietic, hematopoietic progenitor, endothelial, and osteoblast cell populations. Real time RT-PCR analyses showed that osteoblasts and to a lesser degree endothelial cells are the major sources of SDF-1 production in the bone marrow. Surprisingly, on a per cell basis, SDF-1 expression per osteoblast was only modestly (less than two-fold) reduced in mice treated with G-CSF. These data raised the possibility that, rather than affecting SDF-1 expression per osteoblast, G-CSF regulated the number of osteoblasts in the bone marrow. To explore this possibility, osteoblast number in the bone marrow was measured by histomorphometry. Indeed, after 5 days of G-CSF treatment, a significant reduction in the number of endosteal osteoblasts was observed [number of osteoblasts per mm bone perimeter ± SEM: 74.8 ± 13.5 (untreated) versus 33.3 ± 3.8 (G-CSF)]. Moreover, expression of osteocalcin (a specific marker of mature osteoblasts) in the bone marrow was sharply reduced during G-CSF treatment: a 47 ± 12 fold reduction in osteocalcin mRNA (relative to b-actin mRNA) was observed in the bone marrow of G-CSF-treated mice compared with untreated mice. Finally, calcein double-labeling experiments showed that the mineral apposition rate was significantly reduced in G-CSF-treated mice. However, RT-PCR analyses showed that the G-CSF receptor is not expressed on osteoblasts. Accordingly, G-CSF had no direct effect on osteoblast activity in vitro. Collectively, these data show that G-CSF potently suppresses osteoblast number/activity in the bone marrow through an indirect mechanism. Since osteoblasts are thought to play a key role in establishing and maintaining the stem cell niche in the bone marrow, these data raise the possibility that G-CSF, by regulating osteoblast function (including SDF-1 expression), may have profound effects on the stem cell niche that ultimately contribute to HPC mobilization.
Study of Lenalidomide Plus Dexamethasone Versus Dexamethasone Alone in Relapsed or Refractory Multiple Myeloma (MM): Results of a Phase 3 Study (MM-010).
Authors: Dimopoulos Meletios A. , Spencer Andrew , Attal Michael , Prince Miles , Harousseau Jean-Luc , Dmoszynska Anna , Yu Zhinuan , Olesnyckyj Marta , Zeldis Jerome , Knight Robert 
Published: April 2020

Abstract
High-dose dexamethasone (Dex) remains a standard therapy for relapsed or refractory MM. Lenalidomide is a novel, orally administered, immunomodulatory drug (IMiD) that has single-agent activity against MM and additive effects when combined with Dex. In this phase 3, multicenter, randomized, double-blind trial, 351 patients with relapsed or refractory MM were enrolled from clinical centers in Europe, Israel, and Australia. Patients were treated with Dex 40 mg daily on days 1–4, 9–12, and 17–20 every 28 days and were randomized to receive either lenalidomide 25 mg daily orally on days 1–21 every 28 days or placebo. Beginning at cycle 5, the dose intensity of Dex was reduced to 40 mg daily on days 1–4 only every 28 days. Patients resistant to Dex were excluded. Patients were stratified with respect to B2M (≤ 2.5 vs. &gt; 2.5 mg/mL), prior stem cell transplant (none vs. ≥1), and number of prior regimens (1 vs &gt; 1). A pre-planned interim analysis of time to progression (TTP; primary endpoint), response (Blade criteria), and safety data was performed by an independent Data Monitoring Committee (IDMC) when at least half the number of disease progressions required for full statistical power had occurred (50% information). The treatment arms were well balanced for prognostic features. With a study duration of 18 months, the median TTP for patients treated with the combination of lenalidomide plus Dex was 13.3 months compared to 5.1 months for patients treated with Dex and placebo (p &lt; 0.000001). The overall response rate was greater in patients who received lenalidomide plus Dex than in patients who were given Dex alone (58% vs. 22%; p &lt; 0.001). Grade 3 or 4 neutropenia adverse events were reported more frequently in patients given combination therapy than in patients treated Dex alone (16.5% vs. 1.2%), however grade 3 or 4 infections were reported with similar frequencies between treatment groups. Thromboembolic events occurred in 8.5% of patients in the lenalidomide/Dex group and in 4.5% of patients in the Dex alone group. Otherwise, the safety profile of lenalidomide/Dex was similar to that of Dex alone.
Conclusion: Combination lenalidomide/Dex is a relatively well-tolerated and active oral regimen for patients with relapsed or refractory MM. The difference in TTP between the 2 arms surpassed the pre-specified O’Brien-Fleming boundary for superior efficacy (p &lt; 0.0015) and the IDMC recommended the data be released to all study participants. Prophylactic antithrombotic therapy should be considered for patients undergoing treatment with lenalidomide/Dex. These data support further evaluation of this combination in previously untreated patients with MM.
Telomere-Based Pre-Clinical Therapy in a Murine Model of Non-Hodgkin’s Lymphoma of the Diffuse Large B Cell (DLCL)Type.
Authors: Longe Harold , Faller Douglas V. , Denis Gerald V. 
Published: April 2020

Abstract
The dual bromodomain Brd2 is closely related to the basal transcription factor TAFII250, which is essential for cyclin A transactivation and mammalian cell cycle progression. Constitutive expression of BRD2 (under Eμ control) in the lymphoid lineage of transgenic mice elevates basal transcription of cyclin A, destabilizes the cell cycle and leads to B cell leukemias and lymphomas that are monoclonal, morphologically uniform, transplantable and highly malignant. The surface immunophenotype of the lymphoma cells is: B220+, CD19+, sIgM+, CD5+, CD9+; B7-1 and B7-2 elevated, CD23low; CD11b-, Ly-6G- and CD49b-, supporting lymphoid-restricted lineage; CD117- (c-kit) and CD127- (interleukin-7 receptor α-chain), consistent with mature cells; CD25-, syndecan-1-, and CD69- and exhibit a high IgM/low IgD ratio, which taken together identify a B-1 cell type. Malignant, proliferating cells infiltrate lymph nodes, liver, lung and kidney, and at late stages, cause anemia and a fatal peripheral leukemia over a 14-day time course from tumor cell transplantation to death. Genome-wide transcriptional expression profiling of these lymphoma cells reveals a transcriptional fingerprint that is most similar to human diffuse large B cell lymphoma (DLCL) with an “activated B cell” signature, consistent with histopathology, and establishes a novel murine DLCL model. DLCL is the most common type of non-Hodgkin’s lymphoma (NHL) in humans; all lymphomas combined are the fifth most common type of cancer diagnosed and the sixth most common cause of death in the United States. We treated syngeneic transplanted mice with CHOP (i.e. cyclophosphamide 40 mg/kg i.v., doxorubicin 3.3 mg/kg i.v., vincristine 0.5 mg/kg i.v. and predisone 0.2 mg/kg p.o. every day for 14 days) and monitored individual lymphoma cells, tagged with human-CD4+, by flow cytometry of lymphoid and non-lymphoid organs. In a novel approach, we supplemented CHOP with DNA oligonucleotides that mimic the chromosomal telomere, which we call a “T-oligo.” Normal cells exposed to this drug in vitro undergo transient cell cycle arrest, but DLCL cells undergo p53-dependent apoptosis. The mechanism immediately suggests a novel method of chemotherapy for leukemia and lymphoma to supplement CHOP. In mice treated systemically with CHOP and T-oligo, we observed major reductions in the leukemic burden in peripheral blood, reduced lymphadenopathy, reduced leukemic infiltrates of non-lymphoid organs and splenomegaly in the combined (“CHOP+T”) regimen over CHOP alone. We also confirmed in normal B lymphocytes that T-oligo causes only cell cycle arrest, not apoptosis. Mice likewise showed low toxicity to T-oligo at the effective doses, opening the way to a more extensive pre-clinical trial of this novel approach to NHL therapy.
Insights into the Basis of Chromosomal Imbalances during the Clonal Evolution of Multiple Myeloma Using SNP Array Analysis.
Authors: Walker Brian A. , Leone Paola E. , Jenner Matthew , Gonzalez David , Ross Fiona M. , Li Cheng , Davies Faith E. , Morgan Gareth J. 
Published: April 2020

Abstract
On the basis of hyperdiploidy, often involving trisomies of chromosomes 3, 5, 7, 9, 11, 15, 19 and 21, and chromosomal translocations multiple myeloma (MM) can be separated into two broad groups. Neither the mechanism leading to the development of these trisomies nor their effect on myeloma pathogenesis is fully understood. With the aim of understanding these two questions further we have analysed the zygosity status and chromosomal copy number of 39 samples from the MRC Myeloma IX trial (9 t(4;14), 15 t(11;14), 15 hyperdiploid) and two cell lines using the Affymetrix 50K SNP mapping arrays. Plasma cells were selected using CD138+ MACS beads to purity greater than 95%. There was a good correlation between the FISH based detection of copy number change and that defined using SNP mapping arrays indicating that the SNP array methodology was robust. In the 24 non-hyperdiploid cases there are examples of chromosomes that are diploid by FISH and by copy number analysis, using a WGSA programme, however in some of these chromosomes there is loss of heterozygosity (LOH) across the whole or part of the chromosome indicating uniparental disomy (UPD). In addition, we demonstrate where there are large regions of UPD on one chromosome there will often be regions of UPD on other chromosomes. In the hyperdiploidy cases we find that large regions of UPD are rare on the trisomic chromosomes, but small regions of LOH exist in all 15 hyperdiploid samples indicating uniparental trisomy which is in agreement to MM cell lines where uniparental trisomy can also be found. In four out of 15 hyperdiploid samples LOH is also seen on tetraploid chromosomes. UPD, therefore, represents an important new mechanism for gene inactivation in myeloma whereby tumour suppressor genes can be inactivated even in the presence of increased copy number. The mechanism underlying this gene activation relies on the loss of one functional allele leaving only a single allele which may be defective. Duplication of the defective allele gives a normal chromosomal number but an abnormal phenotype, which would not be detected by FISH or conventional CGH. Such regions of LOH may arise through gene conversion events and somatic recombination during mitosis. The order in which these events occur in hyperdiploid cells can help in the understanding of the clonal evolution of myeloma. We demonstrate that gene inactivation methods such as deletions or UPD occur prior to chromosome copy number gain as areas of LOH are present on diploid and trisomic chromosomes. In order to understand how such regions of LOH contribute to the pathogenesis of MM and to define critically deregulated genes within these regions, where mutation and methylation may be important, we are currently comparing the SNP mapping arrays with expression patterns using the Affymetrix U133 plus 2 expression microarrays.
Thalidomide Derivative CC-4047 Inhibits Osteoclast Formation by down Regulation of PU.1.
Authors: Lentzsch Suzanne , Anderson Gulsum , Kurihara Noriyoshi , Honjo Tadashi , Anderson Judith , Mapara Markus Y. , Stirling David , Roodman David 
Published: April 2020

Abstract
CC-4047 (Actimid) is an immunomodulatory analog of thalidomide that has stronger anti-myeloma and anti-angiogenic activity than thalidomide, but its effects on human osteoclast lineage are unknown. Early osteoclast progenitors are of hematopoietic origin and progressively differentiate into mature bone resorbing multinucleated osteoclasts. We investigated the effects of CC-4047 and thalidomide on human osteoclastogenesis, using in vitro receptor activator of NFκ-B ligand/M-CSF stimulated culture system of bone marrow cells. Three weeks of treatment of primary bone marrow cultures with 100 μM CC-4047 decreased osteoclast formation accompanied by complete inhibition of bone resorption. Interestingly, osteoclast formation was also inhibited when cultures were treated with CC-4047 only for the first week (90% inhibition). In contrast, inhibitory effect was greatly diminished when the drug was given for only the last week (25% inhibition), indicating that inhibition of osteoclast formation is an early event. The inhibitory effect of CC-4047 on osteoclastogenesis was not induced by cell death, but by a shift of lineage commitment to granulocyte-CFU at the expense of GM-CFU that are osteoclast progenitors. Further studies revealed that this shift is mediated through down regulation of the transcription factor PU.1, which is critical for early osteoclast formation. In contrast to CC-4047, thalidomide was a significantly less potent inhibitor of osteoclast formation and bone resorption. These results provide the first evidence that CC-4047 blocks osteoclast differentiation at the early phase of osteoclastogenesis. Therefore, CC-4047 might be a valuable drug targeting both the tumor and osteoclastic activity in patients with multiple myeloma and potentially other diseases associated with the development of osteolytic lesions.
HoxA10 Represses Transcription of Multiple Genes Encoding Respiratory Burst Oxidase Proteins in Undifferentiated Myeloid Cells.
Authors: Lindsey Stephan , Lu YuFeng , Eklund Elizabeth A. 
Published: April 2020

Abstract
HoxA10 is a homeodomain (HD) transcription factor which is maximally expressed in committed myeloid progenitors and is overexpressed in acute myeloid leukemia (AML). Consistent with this, forced overexpression of HoxA10 in murine bone marrow leads to AML. Our studies identify a mechanism by which HoxA10-overexpression blocks differentiation, contributing to leukemogenesis. Previously, we found that HoxA10 represses transcription of the CYBB gene. This gene encodes the gp91phox component of the phagocyte respiratory burst oxidase and is actively transcribed in myeloid cells differentiated beyond the promyelocyte stage. CYBB transcription continues until cell death and is further increased in mature phagocytes by inflammatory mediators such as IFNg and LPS. In undifferentiated myeloid cells, HoxA10 represses CYBB transcription via a proximal promoter cis element with homology to the consensus sequence for HoxA10 DNA-binding as a heterodimer with Pbx1 (also a HD protein). However, we found that HoxA10 repression of CYBB transcription is Pbx1-independent and HDAC2-dependant. During cytokine induced differentiation, phosphorylation of two HoxA10 HD tyrosine residues decreases DNA-binding affinity and transcriptional repression. In the current studies, we investigate the impact of HoxA10 on transcription of the NCF2 gene. This gene, which encodes the p67phox phagocyte oxidase component, is transcribed concurrently with the CYBB gene during myelopoiesis and the inflammatory response. The NCF2 promoter also includes a sequence homologous to the HoxA10/Pbx1 DNA-binding consensus. In the current studies, we determine that HoxA10 functionally represses NCF2 transcription in undifferentiated myeloid cells in a Pbx1-independent, HDAC2-dependant manner. Additionally, we determine that NCF2-transcriptional repression by HoxA10 is abolished by phosphorylation of HD tyrosine residues in response to differentiating cytokines. In these studies, we also investigate the impact of IFNg-treatment of monocytes on HoxA10 phosphorylation and gp91phox and p67phox expression. We find that treatment of monocytes with this inflammatory mediator results in hyper tyrosine phosphorylation of HoxA10, which is necessary for IFNg-induced gp91phox and p67phox expression in these cells. These experiments suggest that HoxA10 contributes to differentiation block in AML by repressing transcription of genes that confer the mature myeloid phenotype. HoxA10 tyrosine phosphorylation abrogates transcriptional repression and may provide a molecular target for differentiation induction in AML. Additionally, HoxA10 hyper phosphorylation during the inflammatory response further increases oxidase gene expression. This represents the first demonstration that functions of HoxA10 contribute to gene regulation in mature phagocytes, contributing to the system of host defense.
Lineage Instruction by Oncogenic Tyrosine Kinase Fusions.
Authors: Shigematsu Hirokazu , Mizuno Shin-ichi , Iwasaki Hiromi , Arinobu Yojiro , Ozawa Hidetoshi , Sternberg David W. , Huntly Brian , Gilliland D. Gary , Akashi Koichi 
Published: April 2020

Abstract
Oncogenic tyrosine kinase fusions play a key role in transforming hematopoietic stem and progenitor cells. Bcr/Abl (B/A) and TEL/PDGFβR (T/P) tyrosine kinase fusions were isolated from chronic myeloid leukemia and chronic myelomonocytic leukemia respectively. The constitutive activation of these fusions mainly promotes cell growth of target cells inducing myeloproliferative disease (MPD), which could be a precondition for transformation into acute leukemia. We found that these kinase fusions not only stimulate autonomous cell growth, but also specify cells’ myeloid fate by their own myeloid lineage instructive signals. We retrovirally transduced either the B/A or the T/P gene into purified murine hematopoietic progenitor and stem cells. Transducion of B/A or T/P into hematopoietic stem cells (HSCs) and common myeloid progenitors (CMPs) resulted in formation of spontaneous myeloid colony in cytokine- independent manners. Interestingly, B/A-transduced HSCs (B/A+ HSCs) spontaneously formed granulocyte/monocyte (GM) and megakaryocyte/erythroid (MegE) colonies, while T/P-transduced HSCs (T/P+ HSCs) only generated GM colonies. T/P+ HSCs did not generate MegE-related colonies even in the presence of erythropoietin or thrombopoietin, suggesting that T/P transduces GM-restricted permissive signals. Both B/A+ HSCs and T/P+ HSCs displayed markedly reduced potential for B cells in vitro and vivo. We then transduced B/A or T/P into purified common lymphoid progenitors (CLPs) to test their effect on lymphoid commitment. In a limiting dilution assay, 1 in 7 control-GFP transduced CLPs generated B cell progeny in vitro, while only 1 in 150 B/A+ CLP and 1 in 500 T/P+ CLPs differentiated into B cells. Instead, surprisingly, the majority of B/A+ and T/P+ CLPs differentiated into granulocytes and monocytes in vitro and in vivo. These results indicate that B/A and T/P can specify the myeloid fate counteracting the lymphoid differentiation. We then tried to locate the responsible signaling domain for growth-stimulating or instructive signals by utilizing a series of tyrosine-to-phenylalanine mutants of T/P at the major autophosphorylation sites of PDGFβR. The substitution of only two juxtamembrane tyrosine residues resulted in impairment of cytokine-independent cell growth of HSCs. In contrast, CLPs transduced with mutant T/P substituted at all eight major tyrosine residues were still reprogrammed to differentiate into the myeloid lineage. These data collectively suggest that oncogenic tyrosine kinase fusions can specify the leukemic phenotype by their own instructive signals, which use independent signaling domain for growth promoting ones.
Dynamics of Calcium Mobilization in Platelets during Thrombus Formation in a Living Mouse.
Authors: Dubois Christophe , Panicot-Dubois Laurence , Furie Barbara C. , Furie Bruce 
Published: April 2020

Abstract
Platelet accumulation at sites of vascular injury arrests bleeding but also plays a critical role in the pathogenesis of thrombosis, leading to ischemia in myocardial infarction or stroke. Intracellular calcium mobilization in platelets is a critical step in the activation of platelets and formation of the platelet thrombus. Here we show the relationship of the dynamics of intracellular calcium mobilization with platelet accumulation into the developing thrombus in a living mouse. Following injection of 100 x 106 fura-2 loaded platelets into a living mouse we used high speed intravital multi-channel digital fluorescence microscopy to monitor calcium status in circulating and thrombus-bound platelets during thrombus development. One population of platelets binds transiently to the developing thrombus but does not mobilize calcium. The mean duration of platelet-thrombus interaction for these platelets is 11 sec. Another population of platelets undergoes calcium mobilization after binding to the developing thrombus. The time interval from attachment to calcium mobilization for individual platelets varied from 1.0 to 12 sec, with a median of 3.5 sec. More than 90% of platelets that undergo calcium mobilization do so with in 5 sec of attachment. The calcium mobilization in the thrombus bound platelets is reversible. About two thirds of the platelets return rapidly to the basal Ca2+ state while the remaining thrombus bound platelets maintain an elevated Ca2+ level for an extended period. The mean duration of platelet-thrombus interaction is 35 sec with a range of 1.5 sec to 284 sec (median duration 39.5 sec) as calculated from multiple independent observations of single platelets. In each platelet studied, only one calcium peak is detected per platelet. There is a close correlation between the duration of calcium mobilization in an individual platelet and the time that the platelet remains attached to the developing thrombus, suggesting a relationship of calcium-dependent events and platelet-thrombus affinity. A population of platelets binds to the thrombus, mobilizes calcium and remains associated with the thrombus. Using widefield deconvolution techniques to obtain planar images and increased numbers of dye-loaded platelets, individual platelets could be observed undergoing sustained calcium elevation within the thrombus. As the platelet thrombus reaches maximal size at about 120 sec, calcium mobilization continues in the stable core of the thrombus for several minutes, then decreases. These studies describe thrombus formation in a living animal under conditions in which the endothelium and vessel wall, blood cells and plasma components, and flowing blood are preserved in the absence of anticoagulants. Our results indicate that stable platelet thrombus formation is dependent upon durable calcium mobilization, and that intracellular calcium regulates thrombus development and maturation in vivo.