bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identification of SCL and LMO Oncogenes as Transcriptional Repressors of HEB/E2A in the Thymus through Functional Genomic/Genetic Approaches.
Authors: Tremblay Mathieu , Herblot Sabine , Todorova Margarita , Lisi Veronique , Major Francois , Lemieux Sebastien , Hoang Trang 
Published: April 2020

Abstract
The SCL and LMO oncogenes are frequently activated in childhood T cell acute leukemia (T-ALL). SCL is a bHLH transcription factor that forms heterodimers with other members, specifically HEB and E2A. SCL can either activate or repress transcription but its mechanism of action as an oncogene remains to be clarified. Ectopic expression of SCL and LMO in transgenic mice causes thymocyte differentiation arrest during the preleukemic phase with aberrant differentiation at the DN3–DN4 stage, prior to the acquisition of CD4 and CD8. We therefore took several approaches to define the mechanism underlying this differentiation arrest. Using a CD3e-deficient background to eliminate preTCR signaling effects, an event that is not essential for leukemogenesis, we first analyzed global gene expression of pre-leukemic SCLtg/LMOtg DN3 thymocytes against their non-transgenic littermates via the Affymetrix platform. In this context, SCL/LMO globally affects the expression of both positive and negative targets of E2A/HEB. These results were confirmed by real-time quantitative PCR, showing that SCL/LMO repress E2A/HEB activity. Second, bioinformatic analysis of genes significantly affected by SCL/LMO allowed us to identify phylogenetically conserved HEB/E2A binding sites within the promoter regions of half of these genes. E2A/HEB binding was directly assessed through chromatin immunoprecipitation of primary thymocytes, confirming known target genes and revealing novel ones. This assay also showed that SCL associates with HEB and/or E2A on DNA. Moreover, structure function analysis indicate that transcription inhibition by SCL depends on its HLH domain but not on LMO interaction. We therefore conclude that SCL inhibits thymocyte differentiation by inhibiting E2A/HEB targets that include genes required for thymocyte differentiation, cell signalling, DNA repair and replication. Finally, using a genetic approach we show that SCL/LMO collaborates with HEB haploinsufficiency in inducing leukemia. Our observations therefore reveal that the repression of HEB/E2A by SCL/LMO is a crucial step in T cell transformation.
Support from CIHR and FRSQ.
Bcl11a Causes p21Cip1 Down-Regulation and Transplantable Leukemia in Nf1-Deficient Mice.
Authors: Yin Bin , Delwel Ruud , Valk Peter J. , Loh Mignon L. , Shannon Kevin M. , Largaespada David A. 
Published: April 2020

Abstract
Inactivation of the tumor suppressor gene, NF1, is associated with chronic and acute forms of myeloid diseases including juvenile myelomonocytic leukemia. Nf1-deficiency mouse models have shown some phenotypes reminiscent of those of the human disease. However, Nf1mutation in itself does not lead to leukemia. We reported the identification of 37 common proviral insertion sites, loci containing candidate genes whose mutation could cooperate with inactivation of Nf1 to result in BXH-2 AML. Among these candidate genes, Bcl11a, was able to cause leukemia/lymphoma in bone marrow transduction and transplantation assay using Nf1-deficient cells. In this report, we have found that transplantation of these leukemia cells induced secondary leukemia in syngeneic recipient mice. In patients, we previously reported that BCL11A was expressed in juvenile myelomonocytic leukemia and chronic myelomonocytic leukemia samples. Interestingly, high expression levels of BCL11A are also observed in two specific subsets of samples from a large cohort of patients with acute myelogenous leukemia. Moreover, these subsets of patients tended to have a worse outcome. Regarding the biochemical mechanisms underlying the oncogenicity of Bcl11a, we have recently found that p21Cip1 induction by doxorubicin is severely impaired in Bcl11a-expressing cells, while other cell-cycle regulatory proteins are not affected. Examination of BCL11A’s role in leukemia patients using both over-expression and shRNA knocking-down approaches is underway.
Galiximab Sensitizes Malignant Human B Cell Lines to Apoptosis by Chemotherapeutic Drugs.
Authors: Baritaki Stravroula , Suzuki Eriko , Vega Mario , Ho Steffan , Hariharan Kandasamy , Bonavida Benjamin 
Published: April 2020

Abstract
Galiximab is a primatized anti-CD80 antibody that is being investigated as a treatment for non-Hodgkin’s lymphoma. Results to date from clinical trials indicate that galiximab is well-tolerated and suggest clinical activity both as monotherapy and in combination with rituximab (anti-CD20). CD80 (B7.1), expressed not only by malignant B cells but also by normal B cells, monocytes/macrophages, dendritic cells as well as T cells, plays an important role in the complex and dynamic regulation of adaptive immunity by interacting with either co-stimulatory (e.g. CD28) or co-inhibitory (e.g. CTLA-4, PD-L1) receptors expressed by T lymphocytes. Inhibition of anti-lymphoma immunity that exists within the tumor microenvironment may reflect selection of inhibitory immune regulation mediated through CD80. Galiximab may thus function by directly targeting malignant and possibly non-malignant CD80-expressing cells for antibody-dependent cytotoxicity, or by blocking CD80 interactions involved in suppressing anti-tumor immunity. In preclinical xenograft models, which do not assess the effect of galiximab on non-malignant cells given a lack of cross-reactivity with murine CD80, treatment with galiximab exhibited enhanced tumor growth inhibition when used in combination with either rituximab or with the chemotherapeutic drugs fludarabine and doxorubicin (Hariharan et al., abstract 3040, ASCO, 2007). However, the mechanisms by which galiximab enhances the cytotoxic effects of chemotherapy remain unclear. Rituximab has been shown by us to chemosensitize tumor cells by inhibiting intracellular survival pathways. Thus, we hypothesized that treatment of B lymphoma cells with galiximab facilitates the cytotoxic activity of chemotherapeutic drugs by modifying intracellular anti-apoptotic signaling pathways, resulting in the alteration of pro and anti-apoptotic gene products. The above hypothesis was examined using Raji (Burkitt lymphoma) and IM-9 (multiple myeloma) cell lines as models. Treatment with galiximab resulted in significant inhibition of cell growth and proliferation and modest apoptosis with high concentration. Both Raji and IM-9 are resistant to chemotherapeutic drugs; however, pretreatment with galiximab significantly sensitized the tumor cells to apoptosis induced by CDDP. The synergy achieved was found with subtoxic concentrations of CDDP (5–10 ug/mL) and galiximab. Analysis of the survival pathways and gene products regulating apoptosis following treatment with galiximab, CDDP, and combination will be presented. The present findings demonstrate that galiximab can synergistically enhance cytotoxicity mediated by chemotherapeutic drugs. These findings suggest that in vivo galiximab may have a chemosensitizing effect on resistant B cell malignancies, in addition to its direct cytotoxic effect via ADCC and CDC. The clinincal relevance of these findings will be discussed.
Phase II Pilot Study of Rituximab + CHOP in Patients with Newly Diagnosed Waldenström’s Macroglobulinemia, an Eastren Cooperative Oncology Group Trial (Study E1A02).
Authors: Abonour Rafat , Zhang Lijun A. , Rajkumar Vincent , Srkalovic Gordan , Greipp Philip R. , Fonseca Rafael , Gertz Morie 
Published: April 2020

Abstract
Waldenström’s Macroglobulinemia (WM) is a low-grade lymphoplasmacytic disorder associated with an IgM monoclonal protein that may present with anemia, lymphadenopathy, and hepatosplenomegaly. Since combination chemotherapy and Rituximab are both active in this disease, it is possible the response rate can be enhanced by using a combined modality of Rituximab and CHOP. This approach has been used in indolent lymphoma with remarkable results and limited toxicity.
Objective: To determine the response rate in previously untreated patients with Waldenström’s Macroglobulinemia receiving rituximab and CHOP.
Methods: This was a phase II study of standard R-CHOP in symptomatic WM patients. The study was activated on June 15, 2004 and closed on April 26, 2007 due to poor accrual. The median age of the sixteen patients enrolled was 60 (44–79 years), β2M 3 ug/ml (2.1–7.6), median hemoglobulin was 9 g/dl (7.7–10.9), Viscosity 3.4(1.6–10), and IgM 6389 (3229–13300 mg/dl). The most common symptoms were Fatigue (13/16), visual disturbance (7/16) and parasthesias or painful/numb feet (6/16). Only one patient had bulky adenopathy (6.3%).
Results: Of 16 patients treated, 5 patients have no response data available (it will be presented at the meeting). Objective response was 91% (90% CI: 63.5% ∼ 99.5%) and 1 patient had a minor response with an overall response rate of 100%. Median time to response was 1.6 months from registration and median time to maximum response was 2.1 months. Median duration of response has not been reached. The median follow up time of the 16 patients was 18.3 months with a range of 3.6–24.8 months. Among the 16 treated patients, there were 8 (50%, 90% exact binomial CI: 27.9%∼72.1%) grade 4 neutropenia. 8 patients experienced grade 3 lymphopenia (50%, 90% exact binomial CI: 27.9%∼72.1%). Only 2 grade 3 febrile neutropenia were noted. As of August 4, 2007, none of the 16 patients has died. R-CHOP is a promising regimen in the treatment of patients with Waldenström’s Macroglobulinemia. To succeed in completing clinical trials in this rare disease better international collaboration and involvement in advocacy groups are required.
Activation of Transforming Growth Factor β1 (TGF-β1) Released by Platelets Is Enhanced by Shear and Occurs in Platelet-Rich Thrombi In Vivo.
Authors: Ahamed Jasimuddin , Burg Nathalie , Janczak Christin , Li Jihong , Coller Barry S. 
Published: April 2020

Abstract
Platelets contain 40–100 times as much transforming growth factor β1 (TGF-β1) as other cells, and release it as an inactive (latent) complex. Although several TGF-β1 activating factors have been identified in various cell types, it is still not known whether and how platelet TGF-β1 becomes activated in vivo. In the present study, cell-free human washed platelet releasates (supernatant after stimulation with thrombin 0.125U/ml for 5 min) or serum samples were subjected to either stirring (1,200 rpm) in an aggregometer or a shear stress of 1800 s−1 in a cone and plate device at 37°C. Activation of TGF-β1 was analyzed by ELISA and selectively confirmed using a cell-based plasminogen activator inhibitor 1 (PAI-1) luciferase reporter assay. TGF-β1 was maximally released within 5 min after stimulation of platelets with thrombin (80 ± 23 ng/ml; n=3), but only 0.2% was active. TGF-β1 activity increased slowly and progressively under shear, reaching a maximum of ∼5% of total TGF-β1 (4.1 ± 1.5 ng/ml) after 1 h. In sharp contrast, in two experiments conducted without shear, active TGF-β1 constituted 0.04 and 0.2% of total at 0 time and remained nearly the same (0.1 and 0.2% of total) after 2 h. Activation of TGF-β1 in serum under shear occurred more slowly, but also reached a maximum of ∼5% of total at 2 h (4.1 ± 1.3 ng/ml active; 76 ± 14 ng/ml total; n=6). Without shear at 0 time, active TGF-β1 constituted 0.02 and 0.06% of total and at 2 h it was still only 0.05 and 0.07% of total. To asses whether TGF-β1 becomes activated in vivo during thrombosis, we induced thrombi in the carotid arteries of C57/BL mice with ferric chloride (8%) for 3 min and then removed the platelet-rich thrombi that formed after 5 or 120 min. The arteries were excised (∼4 mm) and the thrombi were removed and dispersed in buffer (200 μl) on ice for 1 h. Total TGF-β1 recovered from 5 min thrombi was 3.4 and 4.8 ng/ml and total TGF-β1 recovered from 120 min thrombi was 3.7 and 0.7 ng/ml. Active TGF-β1 could be detected in thrombi after 5 min and constituted 1.7 ± 1.1% of the total TGF-β1 recovered (n=3). After 120 min, active TGF-β1 could also be detected in thrombi and it constituted 5.1 ± 3.0% of the total recovered (p=0.14 compared to 5 min value; n=3). In sharp contrast, only 0.05% of TGF-β1 released by thrombin from mouse platelets in vitro was active without stirring or shear (n=3). These data indicate that shear can dramatically enhance TGF-β1 activation after release from platelets. Moreover, TGF-β1 activation occurs in vivo during platelet-rich thrombus formation and thus platelets may be an important source of active TGF-β1 in cardiovascular disease and wound healing.
CalDAG-GEFI and Protein Kinase C (PKC) Represent Alternative Pathways Leading to Activation of Integrin αIIbβ3 in Platelets.
Authors: Bergmeier Wolfgang , Crittenden Jill R. , Piffath Crystal L. , Cifuni Stephen M. , Wagner Denisa D. 
Published: April 2020

Abstract
Second messenger-mediated inside-out activation of integrin αIIbβ3 is a key step in platelet aggregation. We have recently shown strongly impaired aggregation in response to various agonists in CalDAG-GEFI-deficient platelets. Thrombin-induced aggregation, however, was affected only at low but not high doses of the agonist, suggesting CD-GEFI-dependent and -independent pathways for integrin activation in platelets. In this study, we further evaluated the roles of CalDAG-GEFI and PKC for integrin activation in platelets activated with a PAR4 receptor-specific agonist, GYPGKF (PAR4p). Compared to wild-type (WT) controls, platelets treated with the PKC inhibitor Ro31–8220 or CalDAG-GEFI-deficient platelets showed a marked defect in aggregation at low (&lt; 1mM PAR4p) but not high PAR4p concentrations. In contrast, aggregation/αIIbβ3 activation was significantly reduced at any tested PAR4p concentration in CalDAG-GEFI-deficient platelets pre-treated with Ro31–8220. PAR4p-induced αIIbβ3 activation in the absence of CalDAG-GEFI required co-signaling through the Gi-coupled receptor for ADP, P2Y12, while this was not the case in WT platelets treated with Ro31–8220. Consistent with these results, release of ADP-containing dense granules was completely inhibited by Ro31–8220 at all PAR4p concentrations tested. In contrast, dense granule release was impaired at low but not high dose PAR4p in CD-GEFI-deficient platelets. Independent roles of CalDAG-GEFI- and PKC/Gi-signaling were also observed for PAR4p-induced activation of Rap1, with CalDAG-GEFI mediating the rapid activation of this small GTPase. In summary, our studies identify CalDAG-GEFI and PKC as independent pathways leading to Rap1 and αIIbβ3 activation in mouse platelets activated through the PAR4 receptor.
PECAM-1 Is a Negative Regulator of Platelet Activation by Laminin.
Authors: Crockett Jimmy , Newman Peter J. 
Published: April 2020

Abstract
Interaction of resting platelets with exposed components of the subendothelial matrix is an important activating event that takes place early on at sites of vascular injury. Platelet responses to collagen are mediated both by the integrin α2β1 and the glycoprotein (GP)VI/Fc receptor (FcR) γ chain complex. Upon collagen binding, Src family kinases phosphorylate tyrosines within Immunoreceptor Tyrosine-based Inhibitory Motifs (ITAMs) that are present within the cytoplasmic domain of the FcRγ chain. These phosphorylated ITAMs serve as docking sites for the protein-tyrosine kinase Syk, which, when recruited and activated, initiates the rapid assembly of a series of adaptor proteins and protein-tyrosine kinases that are crucial for platelet activation responses. Recently, platelet activation by laminin, which binds the related integrin α6β1, was shown to also require signaling through the GPVI/FcRγ chain complex. Because the adhesion and signaling receptor, PECAM-1, serves as a negative regulator of collagen-induced platelet activation, we sought to determine whether PECAM-1 might similarly regulate platelet activation by laminin. We found that PECAM-1 became rapidly tyrosine phosphorylated on its cytoplasmic ITIMs following adhesion of either human or murine platelets to immobilized laminin, suggesting that it may be involved in modulating platelet responses to laminin. PECAM-1-deficient murine platelets exhibited both an increased rate and extent of cell spreading on immobilized laminin compared to their PECAM-1-positive, wild-type (wt) counterparts. Granule secretion, as determined by release of serotonin, was also augmented. Taken together, these data support the notion that PECAM-1 is a negative regulator of platelet responses to laminin.
Anemia in Congestive Heart Failure: The Anemia Is Common and Is Associated with More Severe CHF - Results of a National Survey.
Authors: Oster Howard S. , Hoffman Michael , Cohen Eythan , Mittelman Moshe 
Published: April 2020

Abstract
Anemia has been recognized as a risk as well as a precipitating factor in ischemic heart disease, and in congestive heart failure (CHF). However, there are still open questions regarding the prevalence of anemia in CHF, and the severity and associated clinical manifestations of the anemic CHF patient. In order to characterize CHF in Israel, a national survey was conducted during the period March 1–April 30, 2004. Data were collected on all patients with CHF exacerbation admitted to 96 departments of medicine and 26 cardiology units throughout the country. In this study we have focused on anemia in CHF patients with a special emphasis on the differences observed between CHF patients with anemia (A group) and CHF patients with no anemia (NA group).
Results: Of 2388 patients admitted for exacerbation of CHF, 1326 (55.5%) were found to have anemia (&lt;13g/dl for men, &lt;12g/dl women). Both A and NA groups had similar male/female ratio (57.2%/42.8% A vs 53.5%/46.5% NA). The anemic patients (A) tended to be older (74.8 yrs A vs 72.5 yrs NA, p=0.00001), to have more prior hospitalizations (2.0 A vs 1.3 NA, p=0.0001), and to suffer from a more severe CHF. For example, 49.3% of anemic vs only 41% of non-anemic patients were reported to have baseline New York Heart Association (NYHA) class III–IV. Most notably both in-hospital and six-month mortality rates were significantly higher among anemic CHF patients (in-hospital: 6.6% A vs 4.6% NA, p=0.039; six-month: 25% A vs 15% NA, p&lt;0.00001). Interestingly, no difference was observed between the two groups in the percentage of CHF patients taking aspirin prior to admission. However, fewer anemic patients were discharged with aspirin (63.7% A vs 72.7% NA, p=0.00001).
Conclusions: In this large survey of patients with CHF exacerbation, anemia was found to be common and the anemic patients were found to be older, to have more prior hospitalizations, more severe CHF (NYHA class III–IV), and higher in-hospital and six-month mortality rates. Because both groups had similar rates of aspirin usage, it may be suggested that aspirin plays no significant role in the development of anemia in such patients. Thus, the common practice of withholding this medication from anemic CHF patients may deserve reevaluation. Our data call for a prospective clinical trial, which will test the possibility that correction of the anemia (by RBC transfusion or recombinant erythropoietin) can improve the clinical outcome of the anemic CHF patient.
Thrombopoietin Stimulates the Formation of Endothelial Cell-Cell Contacts and Activates the Small GTPase Rap1.
Authors: Tijssen Marloes R. , di Summa Franca , van Stalborch Anne-Marieke , Van der Schoot C. Ellen , van Buul Jaap D. , Hordijk Peter L. , Voermans Carlijn 
Published: April 2020

Abstract
In addition to hematopoietic cells, the receptor for thrombopoietin (Tpo), c-Mpl, is expressed on human umbilical vein endothelial cells (HUVEC). In this study, we demonstrated that Mpl mRNA and protein can also be detected in immortalized human bone marrow endothelial cells (HBMEC). Furthermore, it was investigated whether Tpo affects endothelial monolayer integrity by either cell spreading or cell-cell contacts. By continuously monitoring the electrical resistance of freshly plated HUVEC or HBMEC with ECIS (electric cell-substrate impedance sensing), we observed a significant increase in the electrical resistance when endothelial cells were treated with 100 ng/ml of Tpo just prior to seeding, as shown in the figure below. This increase in electrical resistance was not due to increased cell adhesion or proliferation of the endothelial cells. However, a significant increase in initial spreading could be detected. Besides its effect on spreading, Tpo increased the electrical resistance of a confluent endothelial monolayer when compared to untreated monolayers. This indicates that Tpo promotes the formation of endothelial cell-cell contacts. Indeed, a decrease in immunostaining levels of phosphotyrosine could be observed in monolayers treated with Tpo. Also the junctional protein VE-cadherin showed diminished co-localization with phosphotyrosine staining when cells were treated with Tpo. The small GTPase Rap1 plays an important role in the formation of endothelial cell-cell contacts. In a pull-down experiment, using RalGDS as bait for active Rap1, we could demonstrate that Tpo transiently activates Rap1 in HUVEC. Thus, these results may put Tpo forward as a regulator of endothelial cell-cell contacts, possibly after vascular damage and subsequent release of Tpo by activated platelets. To our knowledge, Tpo is the first cytokine exerting this effect on endothelial cells.
Figure Figure