bluuebunny/crossref_metadata_2025_split huggingface dataset:
Role of Von Willebrand Factor Triplet Bands in Glycoprotein Ib-Dependent Platelet Adhesion Under Flow Conditions
Authors: Schwartz Bruce A. , Kannicht Christoph , Fuchs Birte , Kröning Mario , Solecka Barbera 
Published: October 2019

Abstract
Abstract 3356

Objective:
Multimeric glycoprotein von Willebrand factor (VWF) exhibits a unique triplet structure of individual oligomers, resulting from ADAMTS13 (a disintegrin and metalloproteinase with thrombospondin type 1 motifs 13) cleavage. The faster and slower migrating triplet bands of a given VWF multimer respectively have one shorter or longer N-terminal peptide sequence. Within this peptide sequence, the A1 domain regulates interaction of VWF with platelet glycoprotein (GP)Ib. Distribution of VWF triplet bands is significantly altered in some types of VWD, however, the impact of triplet structure on VWF function has not been investigated so far.

Methods:
Platelet-adhesive properties of two VWF preparations with similar multimeric distribution but different triplet composition obtained by size exclusion in addition to heparin affinity chromatography were investigated for differential functional activities. Preparation A was enriched in intermediate triplet bands, while preparation B predominantly contained larger triplet bands. Collagen- and GPIb-binding was determined by surface plasmon resonance (SPR). Platelet adhesion under flow was determined using flow-chamber models.

Results:
Binding studies revealed that preparation A displayed a reduced affinity for recombinant GPIb, but an unchanged affinity for collagen type III, when compared to preparation B. Under high-shear flow conditions, preparation A was less active in recruiting platelets to collagen type III. Furthermore, when added to blood from patients with von Willebrand disease (VWD), defective thrombus formation was less restored.

Conclusion:
Thus, VWF forms lacking larger size triplet bands appear to have a decreased potential to recruit platelets to collagen-bound VWF under arterial flow conditions. By implication, changes in triplet band distribution observed in patients with VWD may result in altered platelet adhesion at high-shear flow.

Disclosures:
Schwartz: Octapharma: Employment. Kannicht:Octapharma: Employment. Fuchs:octapharma: Employment. Kröning:octapharma: Employment. Solecka:Octapharma: Employment.
Expression of Let-7 Micro RNAs in Transgenic Mice Overexpressing Truncated Hmga2
Authors: Ikeda Kazuhiko , Harada Kayo , Ogawa Kazuei , Mason Philip J , Bessler Monica , Takeishi Yasuchika 
Published: October 2019

Abstract
Abstract 3470
Expression of HMGA2 is negatively regulated by binding of let-7-family micro RNAs (miRNAs) to specific sites in 3' untranslated region (UTR) of HMGA2. Either downregulation of let-7 or truncation of HMGA2 is thought to cause overexpression of HMGA2. Overexpression of HMGA2 mRNA due to truncation of its 3'UTR by chromosomal translocation was reported in 2 patients with paroxysmal nocturnal hemoglobinuria (PNH; Inoue et al, Blood, 2006). Accordingly, we recently established transgenic ΔHmga2 mice with 3'UTR-truncated Hmga2 cDNA, which revealed a clonal growth advantage of hematopoietic cells overexpressing Hmga2 mRNA that may lead to expansion of a PNH cell (Ikeda et al, Blood, 2011). It has also been reported that HMGA2 mRNA is overexpressed whereas let-7b and −7c are downregulated in peripheral blood cells from the majority of patients with PNH (Murakami et al, BJH, 2012). Although downregulation of let-7-family miRNAs may in part explain overexpression of HMGA2 mRNA, not only full-length HMGA2 mRNA but also short transcript variants of HMGA2 mRNA without 3'UTR are overexpressed in most of these patients. Thus, we aimed to investigate the influence of overexpression of 3'UTR-truncated Hmga2 mRNA, which mimics its short transcript variant, on expression of let-7-family miRNAs. We evaluated expression of let-7a, -7b, and -7c miRNAs in bone marrow (BM) and spleen cells of 12 week-old ΔHmga2 mice (n= 3–4) and wild-type (WT) mice (n= 3–4) using quantitative real-time RT-PCR. Relative expression levels of let-7a (mean ± SD, 1.14 ± 0.57 and 1.62 ± 1.05, respectively), -7b (0.76 ± 0.38 and 1.14 ± 0.77), and -7c (0.62 ± 0.47 and 0.96 ± 0.51) of BM cells were not significantly different between WT mice and ΔHmga2 mice. However, relative expression level of let-7c was significantly higher in spleen cells of ΔHmga2 mice (11.75 ± 2.10) compared with WT mice (1.47 ± 1.19; P &lt; .01). Expression of let-7a (2.46 ± 2.72 and 20.20 ± 25.22) and −7b (1.43 ± 1.62 and 5.27 ± 4.05) was not significantly different in spleen between WT mice and ΔHmga2 mice. Relative expression levels of let-7c were higher in spleen cells compared with those in BM cells in ΔHmga2 mice (P &lt; .01). Therefore, differences in cell lineage or differentiation status might alter expression of let-7-family miRNAs and 3'UTR-truncated Hmga2 may further influence let-7 expression in a tissue specific manner. However, the cause of downregulation of let-7b and -7c, and overexpression of 3'UTR truncated variants of HMGA2 in patients with PNH remains to be elucidated.

Disclosures:
No relevant conflicts of interest to declare.
C/EBPα-Induced Microrna-30c Directly Targets Notch1 During Granulopoiesis and Is Repressed in Acute Myeloid Leukemia
Authors: Katzerke Christiane , Madan Vikas , Gerloff Dennis , Braeuer-Hartmann Daniela , Hartmann Jens-Uwe , Wurm Alexander Arthur , Mueller-Tidow Carsten , Schnittger Susanne , Tenen Daniel G. , Niederwieser Dietger , Behre Gerhard 
Published: October 2019

Abstract
Abstract 3514
The transcription factor CCAAT Enhancer Binding Protein alpha (C/EBPα) is crucial for normal granulopoiesis and frequently disrupted in acute myeloid leukemia (AML). Mutations in the CEBPA gene are reported for about 10% of all AML. Loss of function of C/EBPα leads to a block of myeloid differentiation. MicroRNAs (miR) inhibiting translation of mRNA into protein were identified as critical players in granulocytic differentiation. We and others have already shown that C/EBPα exerts its effects by regulating miRNAs such as miR-223 and miR-34a. In a global microRNA-array we found miR-30c as a novel most important target of C/EBPα during granulopoiesis. Wild-type C/EBPα-p42 up regulates miR-30c expression, whereas the C/EBPα-p30 mutant, found in AML, does not. Furthermore, miR-30c expression is up regulated by G-CSF during granulocytic differentiation of primary human CD34-positive progenitor cells and down regulated in various subtypes of AML. Among these, miR-30c is significantly down regulated in samples from AML with normal karyotype and CEBPA mutations compared to AML patients with CEBPA wildtype. In mice, miR-30c shows a high expression in GMP and granulocytes. An induced tissue specific knock-out of C/EBPα in mice leads to a significant suppression of miR-30c expression in bone marrow cells. A luciferase reporter assay identifies NOTCH1 as a direct target of miR-30c as evident by its binding to the 3'UTR. Recent studies show that Notch1 blocks protein expression of C/EBPα-p42 by activation of Tribbles homolog 2 (Trib2). On the other hand, Proteins of Notch1 and Trib2 are down regulated by C/EBPα-p42. A block of miR-30c by locked nucleic acid (LNA) oligonucleotides prevents C/EBPα–induced downregulation of Notch1 protein expression, thus, miR-30c is necessary for C/EBPα to block NOTCH1. In this direction, the network leads to a block of granulopoiesis and further to leukemogenesis. Our study indicates that C/EBPα-induced miR-30c inactivates Notch1 during granulopoiesis and is down regulated in AML. This data stress the important role of deregulated miRNA expression in leukemia and may provide novel biomarkers and therapeutic targets in AML.

Disclosures:
Schnittger: MLL Munich Leukemia Laboratory: Equity Ownership.
Microrna-143 Blocks ERK5 Signaling During Granulocytic Differentiation of Hematopoietic Stem Cells and Is Downregulated in AML
Authors: Hartmann Jens-Uwe , Braeuer-Hartmann Daniela , Schödel Cindy , Gerloff Dennis , Katzerke Christiane , Müller-Tidow Carsten , Tenen Daniel G. , Niederwieser Dietger , Behre Gerhard 
Published: October 2019

Abstract
Abstract 3516
Mitogen-activated protein kinase (MAPK) pathways are a family of related and sometimes interconnected pathways and one of the most studied. Over the last years, extensive work has established that these proteins play a critical role in G-CSF mediated maturation of neutrophil granulocytes. Understanding the mechanisms by which the MAPK pathways are regulated represents an important area of investigation. MicroRNAs, a class of small non-coding RNAs, have been found to play an important role in the regulation of diverse cellular processes by binding to target mRNAs leading to their translational repression. Deregulation of certain microRNAs, thereby, may lead to disrupted signal pathways, such as MAPK-signaling, and to tumorigenesis. However, the role of microRNAs in hematopoietic differentiation and development of leukemia remains largely unknown. In this study we performed a global screen to identify microRNAs involved in G-CSF-regulated MAPK-pathways in primary human CD34+ hematopoietic progenitor cells. Here we found microRNA-143 (miR-143) to be frequently upregulated in G-CSF stimulated CD34+ cells with a strong correlation to CD15 expression. We could also show the granulopoietic association of miR-143 in several hematopoietic cell line models and acute myeloid leukemia (AML) patient samples. Especially, AML patient samples FAB M4 and M5, which show monocytic phenotypes, had a significant lower expression level of miR-143 compared to the AML FAB types M0, M1, M2, and M3. In general, miR-143 expression was shown to be downregulated in AML patient samples in comparison to normal CD34+ hematopoietic progenitor cells. Most interestingly, we show that miR-143 expression is upregulated in acute promyelocytic leukemia (APL) patients after ATRA treatment. By in silico prediction we found MAPK protein family members (eg. MAPK1, MAPK3 and MAPK7) as predicted targets of miR-143. Western blot analysis of AML patient samples and G-CSF stimulated CD34+ cells clearly show an inverse correlation of miR-143 and MAPK7 (ERK5) protein expression. Finally, by transient overexpression of miR-143 we could show a strong downregulation of ERK protein expression in NB4 cells. Our study suggest that miR-143 upregulation by G-CSF may be an important regulatory step for permitting neutrophil differentiation. MicroRNA-143 blocks ERK5 signaling in G-CSF-induced granulopoiesis of CD34+ hematopoietic stem cells, is downregulated in myelo-monocytic acute myeloid leukemia subtypes, and upregulated after ATRA treatment in APL patients. This information may prove useful for the understanding of conditions in which neutrophil proliferation/differentiation balancing is dysregulated, such as in myeloid leukemia and myelodysplastic disorders.

Disclosures:
No relevant conflicts of interest to declare.
Possible Association Between Acute Myelogenous Leukemia and Thrombopoietin Receptor Agonist in Immune Thrombocytopenia Patients: A Preliminary Signal Report
Authors: Yuji Koichiro , Tanimoto Tetsuya , Tojo Arinobu , Hinomura Yasushi , Yasuo Oshima 
Published: October 2019

Abstract
Abstract 3541

Background
One of the concerns of potential adverse reactions of thrombopoietin receptor (MPL) agonists (romiplostim and eltrombopag) is development of myeloid malignancies. Progression from myelodysplastic syndrome to acute myelogenous leukemia (AML) has been reported in romiplostim. However, development of AML in immune thrombocytopenia (ITP) patients has not been reported. The objective of this study is to clarify whether the concern of AML in MPL agonists in patients with ITP is worth further investigation.

Method
We performed a disproportionality analysis on patients with ITP registered in an adverse event database, AERS between 2002 and 2011. We compared characteristics between AML case and others.

Results
Total of 4,821 subjects were identified as ITP and 62 AML cases among them in the AERS. The proportion of AML reporting in romiplostim and eltrombopag were 1.73% (95%CI; 1.30–2.26%) and 1.35% (0.62–2.54%), respectively. It should be noted that all AML was reported with one or more MPL agonist(s). Other factors associated with AML were male gender (OR 2.01; 95%CI 1.03–3.91) and age between 60 and 69 (OR 2.22; 95%CI 1.16–4.24).

Conclusion
We reported possible association between AML and MPL agonist use in ITP subjects. Due to limitations of spontaneous reporting, further studies are warranted to determine whether the detected signal is real risk or not. Prescribing physicians should not alter their prescribing behaviors based on only this preliminary analysis.

Disclosures:
Tojo: Novartis Pharma K.K.: Research Funding; Bristol-Myers Squibb Company: Research Funding; Chugai Pharmaceutical Co., Ltd.: Research Funding; Otsuka Pharmaceutical Co., Ltd.: Research Funding; Dainippon Sumitomo Pharma Co., Ltd.: Research Funding; Celgene K.K.: Consultancy. Yasuo:sanofi-aventis K.K.: Employment.
Azacitidine Plus Lenalidomide for Untreated AML Patients Ineligible for Conventional Chemotherapy
Authors: Pollyea Daniel A , Zehnder James L. , Coutre Steven , Gotlib Jason , Gallegos Leonel , Greenberg Peter , Zhang Bing , Liedtke Michaela , Levine Ross L. , Medeiros Bruno C. 
Published: October 2019

Abstract
Abstract 3575
There are limited treatment options for older patients with acute myeloid leukemia (AML) and prognosis has remained poor, thereby warranting development of novel therapeutic strategies. The optimal treatment for these patients requires the consideration of multiple factors, such as patient and disease-related factors that can help to determine the appropriate therapy. Previous studies have shown that both azacitidine and lenalidomide have single-agent activity in patients older than 60 years with untreated AML and have non-overlapping mechanisms of action that may complement each other. We evaluated the efficacy and safety of the combination of azacitidine plus lenalidomide as front-line therapy for untreated, older AML patients. In this phase 2 study, patients 60 years of age or older with untreated AML received azacitidine 75mg/m2 for 7 days followed by escalating doses of lenalidomide daily for 21 day on 42-day cycles. Patients received continued therapy until disease progression, an unacceptable adverse event, or completion of 12 cycles. Forty-one AML patients (median age, 74 years) were enrolled with equal distribution according to ELN risk. Overall response rate (ORR) was 41% (CR/CRi rate was 29%). The median time to CR/CRi was 12 weeks, and duration of CR/CRi was 28 weeks (range, 4- >104 weeks). The median OS was 20 weeks (range, 1–121+) for the entire cohort and 69 weeks (range, 10–121+) for responders (Figure 1A; responders had better OS compared to non-responders (69 vs. 15 weeks, p-value <0.01). Baseline characteristics, such as age at diagnosis, baseline WBC count, bone marrow blast percentage or ELN risk classification, or molecular markers were not predictive of responses. Overall survival was similar according to ELN classification. Therapy-related AML and high hematopoietic cell transplantation comorbidity index were the only negative predictors of response. Early death was noted in 14% of patients. Grades ≥ 3 toxicities were uncommon and most adverse events were gastrointestinal, fatigue and myelosupression. Sequential combination of azacitidine plus lenalidomide has evidence of clinical activity as initial therapy for older AML patients, and further study of this combination in AML and MDS is warranted. This study is registered at www.clinicaltrials.gov as # NCT00890929.

Disclosures:
Gotlib: Celgene: Research Funding. Liedtke:Celgene: Research Funding. Medeiros:Celgene: Consultancy, Research Funding. Off Label Use: Treatment of AML.
Health Related Quality of Life of Bosutinib in Imatinib-Resistant or Imatinib-Intolerant Patients with Advanced Chronic Myeloid Leukemia
Authors: Whiteley Jennifer , Reisman Arlene , Kelly Virginia , Cortes Jorge E , Cella David 
Published: October 2019

Abstract
Abstract 4448

Purpose:
Bosutinib is a dual Src/Abl tyrosine kinase inhibitor (TKI), which has demonstrated efficacy in a phase I/II study of patients with Advanced Phase Chronic Myeloid Leukemia (CML). The objective was to evaluate the effect of bosutinib on health -related quality of life (HRQoL) in patients with advanced CML after failure with imatinib.

Methods:
Patient reported HRQoL was an exploratory objective in the clinical trial and measured using the 44-item Functional Assessment of Cancer Therapy-Leukemia (FACT-Leu). The FACT-Leu is a modular approach to assess patient HRQoL using a core set of general cancer questions as well as a cancer site specific leukemia subscale with 5 domains: Social Well-being (SWB), Emotional Well-being (EWB), Physical Well-being (PWB), Functional Well-being (FWB) and Leukemia Subscale (LeuS); and 3 summary scales: FACT-General, FACT Trial Outcome Index (TOI) and FACT-Leu Total. The item responses for each scale are summed to provide scores; higher scores indicate better HRQoL. The FACT-Leu was completed at weeks 4, 8, 12 and every 12 weeks thereafter, as well as treatment completion. Within cohort comparisons were assessed using paired t-tests.

Results:
Of the 164 patients with advanced leukemia included in the trial, 76 had accelerated phase (AP) CML and 64 blast phase (BP) CML. At 24 weeks, AP patients reported statistically significant improvements in PWB (p=0.02), EWB (p<0.001), LeuS (p<0.001), FACT-G (p<0.001), FACT-Leu (p<0.001) and FACT-TOI (p<0.001) with the PWB, FACT-G, LeuS, TOI and FACT-Leu exceeding minimally important differences (MID) at 24 weeks. Blast phase patients reported significant improvements in PWB (p=0.02), EWB (p=0.02), FWB (p=0.04), LeuS (p=0.01), FACT-G (p<0.001), FACT-Leu (p<0.001) and FACT-TOI (p=0.01) at 24-weeks with all scales exceeding MID except the SWB. At 48-weeks the AP patients continued to have statistically significant improvements in PWB (p=0.05), EWB (p=0.02), and FACT-G (p=0.03) and PWB, FACT-G, TOI and FACT-Leu exceeded the MID at 48 weeks. There were no statistically significant deteriorations in HRQoL through week 48 (Figure 1)

Conclusions:
These data suggest that CML patients treated with bosutinib demonstrate improved HRQoL. Confirmation in a controlled study is needed.

Disclosures:
Whiteley: Pfizer Inc: Employment, Equity Ownership. Reisman:Pfizer Inc: Employment, Equity Ownership. Kelly:Pfizer Inc: Employment, Equity Ownership. Cortes:Novartis, Bristol Myers Squibb, Pfizer, Ariad, Chemgenex: Consultancy, Research Funding. Cella:Pfizer Inc: Honoraria, Research Funding.
Molecular Response to Tyrosine Kinase Inhibitors (TKIs) for Chronic Myeloid Leukemia (CML), the Experience At Tawam Hospital, Abudhabi, UAE
Authors: Alam Arif , Hussain Sabir , Lal Amar , Lee Donna , Kristensen Jorgen 
Published: October 2019

Abstract
Abstract 4458
Chronic Myeloid Leukemia (CML) is a clonal myeloproliferative disorder characterized by the presence of a balanced reciprocal translocation involving the long arms of chromosomes 9 and 22. The fusion gene that is created by this translocation (BCR-ABL1) encodes for a constitutively active protein tyrosine kinase that is primarily responsible for the leukemic phenotype.
Targeted therapy with Tyrosine Kinase Inhibitors (TKIs) has become the recommended first-line treatment for patients with CML. Monitoring of the CML is done with quantification of the BCR-ABL transcripts by RQ-PCR–based molecular technique.
Twenty nine patients were diagnosed with CML in chronic phase between January 2009 till June 2012. The median age was 32 years (range 22–68 years). Male to female ratio was4.14:1. Three patients were lost from follow up after diagnosis and are excluded. Molecular response is available for 16 patients. Nine patients were treated with Imatinib 400 mg daily, four with Dasatinib 100 mg daily and three with Nilotinib 400 mg BID daily as upfront therapy. Twelve patients have achieved MMR/CMR (75 %) within 18months of starting therapy. Four patients have failed to achieve MMR by 24 months. All non responders were on Imatinib. Interestingly six (37.5%) patients achieved MMR/CMR within 9 months of starting TKIs. Of these only 1 was on Imatinib while the rest were on 2nd generation TKIs (Nilotinib 3 and Dasatinib 2).
MMR report from Enestnd trial is 67–71% in favor of Nilotinib as compared to Imatinib 44%, while the Dasision trial reported a MMR of 44 % in favor of Dasatinib with faster rate to response. Our results mirror the results of these phase 3 randomized trial with MMR/CMR of 75 %. Until today there has been no case of progressive disease.
Our data is limited but shows that the median age is much lower compared to Western countries, just reflecting differences in the age distribution of the population in the UAE with 80% being below the age of 65 years. Expatriates accounts for approximately 80% of the population in the UAE and many are temporary employed, having limited health care coverage, limited financial means as well as limited possibilities to attend regular follow-ups. This leads to compliance problems, loss from follow-up and suboptimal management and monitoring of their disease.

Disclosures:
Alam: BMS/Novartis: Consultancy, Honoraria. Hussain:BMS: Consultancy, Honoraria.
Outcome of Second Allotransplantation for Relapsed Hematologic Malignancies After Stem Cell Transplantation
Authors: Tan Tran-Der , Wu Mau-Ching , Chiou Lun-Wei 
Published: October 2019

Abstract
Abstract 4461

Background
Allogeneic or autologous stem cell transplantation is a curative therapy for hematologic malignant disease including leukemia, lymphoma, and myeloma. However, the most common cause of failure is disease relapse and then the prognosis is grim and life expectancy is limited. For selected patients in second remission after salvage treatment and performance status is good enough, second allotransplant is another chance to achieve durable survival.

Method
This is a retrospective study in the past 7 years. For relapsed hematolgic malignancy patients after first stem cell transplantation and the ECOG performance status is 0 or 1, we treated with reduced intensity (RIC) or myeloablative conditioning (MAC) regimens directly or after salvage chemotherapy to induce second remission.

Results
We treated 24 patients with salvage allogeneic stem cell transplantation including 23 underwent second and one underwent third transplant between September 2005 and October 2011. The follow-up period is between 10 and 82 months. Patients median age is 40 with range between 23 and 59 with male to female 15/9. Disease entities include 10 AML, 5 ALL, 1 CML BP, 3 NHL, 4 HL, and 1 myeloma. The median duration between first transplant and disease relapse is 13.1 months (range between 2.5 and 52 months). The median interval between first and second transplant is 17.4 months (range between 5 and 64 months). The 5-year overall survival rate is 37% for all 24 patients and 55% for the 10 AML patients.

Conclusion
Second allogeneic stem cell transplant is feasable and durable survival is still promising for selected relapsed patients after first transplantation but the treatment modality is very individualized either RIC or MAC allotransplant according to patients disease entity and disease status.

Disclosures:
No relevant conflicts of interest to declare.