bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Polycistronic miRNA Cluster miR-17-92 Is Over-Expressed in Early Phase Chronic Myeloid Leukemia (CML) CD34+ Cells.
Authors: Venturini Letizia , Battmer Karin , Castoldi Mirco , Schultheis Beate , Hochhaus Andreas , Muckenthaler Martina , Ganser Arnold , Eder Matthias , Scherr Michaela 
Published: April 2020

Abstract
Micro RNAs (miRNAs) are small non-coding, single-stranded RNAs regulating gene expression by hybridization to complementary sequences in target mRNAs. Aberrant miRNA expression has been found in a variety of human malignancies including B-cell leukemias and lymphomas. The polycistronic miR-17–92 cluster, which includes seven miRNAs (miR-17-5p, miR-17-3p, miR-18a, miR-19a, miR-20a, miR-19b-1, miR-92-1), resides in intron 3 of the C13orf25 gene located on human chromosome 13 and has recently been described to harbor oncogenic potential in a murine transplantation model. In addition, expression of the polycistron can be regulated by c-myc, which is also activated by the Bcr-Abl oncogene product. To study miRNA expression in CML, K562 cells were analyzed by microarray analysis (miCHIP) for normalized expression of 244 miRNAs following treatment either with
imatinib to inhibit Bcr-Abl kinase activity or with specific anti bcr-abl shRNA to knock-down gene expression.
Both of these treatment strategies led to a 2–4-fold reduction of six mature miRNAs (miR-17-5p, miR-17-3p, miR-18a, miR-20a miR-19b-1, miR-92–1) as compared to untreated control cells. The reduction of the miR-17–92 miRNA cluster expression was confirmed for each individual mature miRNA species encoded in the cluster by real-time RT-PCR. Treatment with either imatinib or anti-bcr-abl shRNA also down-regulates expression of mature miRNA miR-19a (&gt;3-fold) in K562 cells as quantified by real-time RT-PCR. We next used PCR based quantification to analyze miR-17–92 expression in purified normal (n=4) and CML CD34+ cells harvested at diagnosis of chronic phase disease (n=16). Individual mature miRNAs of the cluster were up-regulated (2–6-fold) in CML as compared to normal CD34+ cells. Additionally, the pri-miRNA for the miR-17–92 cluster was up-regulated in 70% (7/10) of CML samples. Interestingly, retrovirus-mediated over-expression of the miR-17-19b-1 cluster in K562 cells mediates enhanced colony-formation of transduced cells. Furthermore, K562 cells expressing high levels of the miR-17-19b-1 cluster are more resistant to proliferation inhibition induced by specific anti-myc RNAi, indicating some functional role of the miR-17-92 cluster on proliferation and survival in this model. In summary, the polycistronic miR-17–92 cluster is up-regulated in early chronic phase CML CD34+ cells and may contribute to cellular transformation by the Bcr-Abl oncogene product.
CD44 Is Selectively Required for the Homing and Engraftment of BCR-ABL-Expressing Leukemic Stem Cells.
Authors: Krause Daniela S. , Lazarides Katherine , von Andrian Ulrich H. , Van Etten Richard A. 
Published: April 2020

Abstract
In chronic myeloid leukemia (CML) patients treated by autologous hematopoietic stem cell (HSC) transplantation, malignant progenitors in the graft can contribute to relapse of leukemia (Deisseroth et al., Blood1994; 83:3068), but the mechanisms of homing and engraftment of leukemic CML stem cells are unknown. Although the frequency of autografting in CML has decreased following the introduction of imatinib, most imatinib-responsive patients harbor residual BCR-ABL-expressing stem cells (Graham et al., Blood2002; 99:319) and some will develop progressive leukemia. Autografting with cells harvested at the time of minimal residual disease could be an important salvage therapy, but methods to selectively block the engraftment of leukemic stem cells are needed. In this study, we show that CD44 expression is increased on murine BCR-ABL-expressing stem/progenitor cells and contributes to the ability of these cells to bind to Selectins. In a retroviral transduction/transplantation model of CML, BCR-ABL-transduced progenitors from CD44-deficient donors were defective in homing to recipient marrow, resulting in defective engraftment and impaired induction of CML-like myeloproliferative disease. By contrast, CD44-deficient stem cells transduced with empty retrovirus engrafted as efficiently as wild-type HSC. In addition, CD44 was not required for induction of acute B-lymphoblastic leukemia (B-ALL) by BCR-ABL, indicating that the engraftment requirement for CD44 is specific to leukemic cells initiating CML, not B-ALL. The requirement for donor CD44 was bypassed by direct intrafemoral injection of BCR-ABL-transduced CD44-deficient stem cells, or by co-expression of human CD44 with BCR-ABL. Treatment of BCR-ABL-transduced stem/progenitor cells from wild-type donors with antibody to CD44 attenuated the induction of CML-like leukemia in recipients. These results demonstrate a major role for CD44 in homing and engraftment of BCR-ABL-expressing leukemic stem cells, possibly through adhesive interactions with Selectins and/or hyaluronan in the recipient bone marrow niche. They further argue that BCR-ABL-transduced stem/progenitor cells depend to a greater extent on CD44 for engraftment than do normal HSC, and suggest that CD44 blockade may be beneficial in autologous transplantation in CML.
Psychosocial Factors as Measured by the Transplant Evaluation Rating Scale (TERS) Predict Length of Hospitalization and Transplant Outcomes Following Hematopoietic Stem Cell Transplantation.
Authors: Speckhart Dawn S. , Solomon Scott R. 
Published: April 2020

Abstract
Although psychological and social factors are recognized as being important in the evaluation of patients for hematopoietic stem cell transplantation (HSCT), no standard approach to psychosocial assessment currently exists. In solid organ transplantation, psychosocial assessments have been integrated into the selection of appropriate candidates, and certain psychosocial variables, such as active substance abuse, have been shown to negatively impact outcomes in solid organ transplant patients. To determine whether similar factors impact outcomes in patients undergoing HSCT, we prospectively conducted psychosocial assessments on 221 consecutive patients (155 autologous, 66 allogeneic) undergoing HSCT. The relationship between psychosocial variables, such as those assessed on the Transplant Evaluation Rating Scale (TERS), and objective outcomes, such as length of hospitalization and survival was evaluated. Based on the patient’s TERS score, each patient was stratified into one of two groups (low/moderate risk (n=187) vs. high risk (n=34)) based on their predicted psychosocial risk for problems during transplant. Although the two groups were similar in regards to known pre-transplant prognostic factors such as age, performance status, disease risk, and transplant type, there was a significant difference in the median length of hospitalization between patients who score low/moderate (10 days) and those who scored high (21.5 days) on the TERS. This difference was significant both for patients receiving autologous (9 vs. 15 days, p&lt;.02) and allogeneic transplants (16 vs. 45 days, p&lt;.001). Furthermore, 2-year overall survival was significantly improved in allogeneic transplant patients who score low/moderate vs. those that scored high on the TERS (72% vs. 46%; p&lt;=.02). These findings suggest a strong correlation between pre-transplant psychosocial risk factors, resource utilization and patient outcome in HSCT.
Figure 1. Overall survival following allogeneic stem cell transplantation according to TERS score Figure 1. Overall survival following allogeneic stem cell transplantation according to TERS score
Allelically Mismatched Replacement Therapy Due to Common African−Restricted Haplotypes of the Factor (F)VIII Protein May Underlie the Increased Incidence of FVIII Inhibitors Observed in Hemophilia−A Patients of African−Descent.
Authors: Howard Tom E. , Viel Kevin R. , Fernstrom Karl M. , Deshpande Seema , Ameri Afshin , Ali M. Showkat , Channell Cynthia , Iyer Rathi V. , Watts Raymond G. , Lutcher Charles , Nakaya Shelley , Kasper Carol K. , Thompson Arthur R. , Abshire Thomas C. , Almasy Laura 
Published: April 2020

Abstract
Alloantibodies that inhibit the function of wildtype (wt) FVIII molecules constitute the most serious complication of replacement therapy for hemophilia (H)A patients. Although it is not possible to accurately predict which patients will develop inhibitors, ethnicity is a known risk factor as alloimmunization occurs ~2−fold more often in African Americans (AAs) than in Caucasians (Cs). Analysis of data from a resequencing study revealed that the FVIII gene (F8) contains four nonsynonymous−single nucleotide polymorphisms (ns−SNPs) that encode six distinct wt FVIII proteins designated haplotype (H)1−H6. While AAs express all but H6, only H1 and H2, the two recombinant (r)−FVIII proteins used clinically, are expressed by Cs. About 25% of AAs express H3, H4, or H5, proteins that differ structurally from r−FVIII at three ns−SNPs (R484H, D1241E, M2238V), two of which are located in dominant inhibitor epitopes and have AA−restricted minor−alleles. We designed the Pharmacogenetics of Inhibitor Risk (PIR) study to test the hypothesis that these ns−SNPs, when allelically mismatched in replacement therapy, are pharmacogenetic risk factors that contribute to the greater incidence of inhibitor development in patients of African−descent. We enrolled 94 of 223 total AA HA patients from collaborating treatment centers. Table 1 presents characteristics of the first 47 subjects (whose functional F8 regions have been resequenced entirely) including: FVIII haplotype (exposure) − H3/H4/H5 vs H1/H2; inhibitor status (outcome) − yes/no; F8 mutation − high−risk vs low−risk types; other covariates and potential confounders. A preliminary analysis demonstrated an odds ratio of 3.6 for inhibitors developing in the exposed subjects (P=0.10; 95% CI=0.7–17.6). Our finding suggests that pharmacogenetic factors may indeed contribute to the increased incidence of this alloimmune complication in AAs. To increase the power to detect a true association and allow adjustment for confounders, we are currently completing F8 resequencing in the next 47 patients.
Table 1. Relevant characteristics of the first 47 African-American hemophilia-A PIR study patients*
A Variant of Recombinant Factor VIIa with Enhanced Procoagulant and Antifibrinolytic Activities in a Model of Hemophilia.
Authors: Wolberg Alisa S. , Persson Egon , Hedner Ulla , Ezban Mirella , Allen Geoffrey A. 
Published: April 2020

Abstract
Recombinant factor VIIa (rFVIIa, NovoSeven; Novo Nordisk A/S, Copenhagen, Denmark) has proven efficacy in treating bleeding in hemophilia patients with inhibitors. We have shown that high concentrations of rFVIIa improve parameters of thrombin generation and fibrin clot formation and stability in an in vitro model of hemophilia (Wolberg et al. 2005 Brit J Haem 131:645–55). Recently, new rFVIIa analogs with increased procoagulant activity have been described. One of these analogs, rFVIIa with mutations V158D/E296V/M298Q (NN1731), exhibits increased activity in in vitro and in vivo models. In the present study, we compared the abilities of rFVIIa and NN1731 to specifically modulate factor X activation, platelet activation, thrombin generation, and fibrin clot formation and stability in an in vitro model of hemophilia. RFVIIa and NN1731 similarly increased factor X activation on tissue factor−bearing monocytes; however, NN1731 exhibited 30−fold higher factor Xa generation rates on activated platelets than similar concentrations of rFVIIa. We employed a complete, cell−based, reconstituted model of coagulation to compare the activities of rFVIIa and NN1731 in hemophilic conditions. The model system consists of tissue−factor bearing monocytes, purified pro− and anti−coagulant proteins (XI, X, IX, VIII, VIIa, V, II, AT, TFPI), and freshly−isolated, unactivated platelets. Fibrinogen is included in certain wells to examine clot formation. “Hemophilia” is simulated by omitting factors VIII and IX. In this assay, NN1731 produced 4 – 10−fold higher maximal thrombin generation rates than equal concentrations of rFVIIa. In contrast to even very high concentrations of rFVIIa (up to 500 nM), NN1731 was able to normalize the rate of thrombin generation. NN1731 did not directly activate platelets and thrombin generation was not detected prior to platelet activation, suggesting that the presence of NN1731 would not lead to thrombin generation in the absence of injury. Both rFVIIa and NN1731 shortened clotting times in the absence of factors IX and VIII; however, NN1731 did so at lower concentrations than were required of rFVIIa. In a plasmin challenge assay, in which clot formation is initiated in the presence of plasmin, both rFVIIa and NN1731 increased fibrin formation and the length of time that fibrin was present in the absence of factors IX and VIII; however, NN1731 was effective at lower concentrations than were required of rFVIIa. Our results indicate that NN1731 increases factor Xa and thrombin generation and promotes clot formation and stability to a greater degree than equal concentrations of rFVIIa. For these reasons, NN1731 may be especially efficacious in situations in which rapid formation of a firm fibrin clot with increased resistance to fibrinolysis is necessary to achieve hemostasis.
Leukemia Stem Cells in Murine MLL−AF9 AML Are Downstream Myeloid Lineage Cells That Have Acquired Stem−Like Biological and Genetic Properties.
Authors: Somervaille Tim C.P. , Cleary Michael L. 
Published: April 2020

Abstract
An essential prerequisite for the development of more effective targeted therapies in AML is a characterization of the frequency and biological properties of leukemia stem cells (LSCs), which sustain the disease and mediate relapse. Previous studies have shown that hematopoietic stem cells, as well as progenitors, may be targeted by MLL oncoproteins to give rise to AML, however it was unclear whether these lineage negative cells also functioned as LSCs to sustain disease. To address this issue, we have identified and characterized LSCs in a somatic, genetic mouse model of leukemia that faithfully recapitulates many of the pathologic and clinical attributes of human leukemia initiated by the MLL−AF9 oncogene. In this model, CFCs in the bone marrow and spleen of leukemic mice were demonstrated to be LSCs, based on the observation that secondary transplantation of the progeny of individually isolated AML CFCs cultured in vitro for seven days or longer invariably resulted in transfer of short latency disease. These self−renewing cells were remarkably frequent, accounting for 25–30% of myeloid lineage cells at late−stage disease. Unexpectedly, they expressed mature myeloid lineage antigens (91.3 ± 3.8% Mac1+ Gr1+ immunophenotype, versus fewer than 0.2% lineage negative), placing them downstream of the known hematopoietic progenitor compartment. Furthermore, LSCs in this model generated a phenotypic, morphologic and functional leukemia cell hierarchy loosely defined by expression of c−kit. When compared with immortalized progenitors, LSCs exhibited a markedly enhanced ability to engraft secondary recipients, which was not due to differences in bone marrow homing, which was equivalently poor in the compared populations. Rather, LSCs exhibited an acquired ability to proliferate in response to stromal cell derived cytokines, an enhanced SDF1 induced chemotaxis, and increased proliferation in contact with OP9 stromal cells demonstrating that LSCs exhibit altered microenvironmental interactions by comparison with the oncogene immortalized CFCs that initiated the disease. Thus, the LSCs responsible for sustaining, expanding and regenerating MLL−AF9 AML are downstream myeloid lineage cells, outside of the normal stem and progenitor compartment. They have acquired an aberrant Hox−associated self−renewal program as well as other biologic features of hematopoietic stem cells. Our findings support a revision of the prevailing hypothesis that AML LSCs are always rare and solely located within the most immature bone marrow progenitor compartment. Furthermore, LSCs exhibit markedly different microenvironmental interactions, by comparison with cells simply immortalized by MLL−AF9, indicating that acquisition of sensitivity to stromal derived survival and proliferative signals is a critical feature of LSCs, in addition to their extensive self−renewal capabilities.
The MAML1 Transcriptional Co-Activator Is Required for the Development of Marginal Zone B Cells.
Authors: Wu Lizi , Maillard Ivan , Nakamura Makoto , Pear Warren S. , Griffin James D. 
Published: April 2020

Abstract
Notch1 and Notch2 receptor-mediated signaling appear to have important and unique roles in lymphoid lineage commitment. Notch1 is required for T cell development, while Notch2 is essential for marginal zone B cell development. This specificity is not completely explained by differential expression patterns of Notch1 and 2 or Notch ligands, suggesting that there are other genes that contribute to specifying Notch receptor functions. We have previously shown that the MAML family of transcriptional co-activators is essential for Notch-induced transcriptional events, and functions by forming ternary complexes with Notch and the transcription factor CSL in the nucleus. This MAML family currently consists of three members, MAML1-3, all of which can function as co-activators for Notch receptors in vitro . In this study, we investigated the possibility that MAML1 co-activator contributes to determining Notch receptor function by generating mice deficient in the Maml1 gene. Maml1 -deficient mice fail to thrive and die within 10 days of birth. The morphology of marrow, nodes, and spleen was grossly intact. The ability of Maml1-deficient stem cells to generate different T and B lineages of lymphoid cells was determined by transplanting fetal liver cells isolated from E14.5 embryos into lethally irradiated wild-type recipient mice and analyzing donor-derived lymphoid cells 12 weeks post-transplantation. We found that the deletion of Maml1 results in complete loss of marginal zone B cell lineage (MZB, defined by B220+CD21hiCD23lo). Moreover, the number of MZB cells was reduced to about 50% in Maml1 -heterozygous fetal liver chimeras as compared to wild type controls. However, T cell development was largely unaffected, with only a modest but significant increase in the number of γδ T cells (about 2 fold) in both the thymus and the spleen. Therefore, these results suggest the unexpected finding that targeted deletion of Maml1 in hematopoietic cells is similar to the targeted deletion of either Notch2 or the Notch ligand, Delta-like 1 (Dll1) resulting in the loss of marginal zone B cells and minimal effects on T cell development. Moreover, the number of marginal zone B cells is correlated with Maml1 gene dosage, indicating haploinsufficiency. These data suggest that the Notch ligand Dll1 activates Notch2 signaling resulting in a Notch2/MAML1/CSL complex that is essential for marginal zone B cell development. Further studies with respect to relative expression levels of various MAML genes and interactions of MAML co-activators and Notch receptors may shed additional light into understanding how different Notch receptors regulate cell fate decisions in hematopoiesis.
A Randomized Phase III Trial of Lenalidomide Plus High-Dose Dexamethasone Versus Lenalidomide Plus Low-Dose Dexamethasone in Newly Diagnosed Multiple Myeloma (E4A03): A Trial Coordinated by the Eastern Cooperative Oncology Group.
Authors: Rajkumar S. Vincent , Jacobus Susanna , Callander Natalie , Fonseca Rafael , Vesole David , Greipp Philip 
Published: April 2020

Abstract
Background: Lenalidomide has shown efficacy in patients with relapsed myeloma in phase II and III clinical trials, and is currently being investigated as initial therapy for the disease. We report results of a phase III trial comparing lenalidomide plus high-dose dexamethasone (Dex) versus lenalidomide plus low-dose Dex as first line therapy in newly diagnosed multiple myeloma (MM).
Methods: Pts with newly diagnosed, untreated, symptomatic MM were eligible. Pts in both arms received lenalidomide 25 mg/day PO on days 1–21 every 28 days. In addition, patients in the high-dose Dex arm (Arm A) received Dex 40 mg on days 1–4, 9–12, and 17–20 PO every 28 days, while pts in the low-dose Dex arm (Arm B) received Dex 40 mg on days 1, 8, 15, and 22 PO every 28 days. The primary endpoint was best response at 4 months on intent to treat basis. At 4 months pts could go off study for stem cell transplant or elect to continue therapy until progression. Response was defined as a decrease in serum and urine monoclonal (M) protein by 50% or higher. If the serum M protein was unmeasurable, a 90% or higher decrease in urine M protein was required. Responses need to be confirmed at least 4 weeks apart. Patients with disease progression or not responding to lenalidomide within 4 months switched to thalidomide with the same dose of dexamethasone they were receiving (Arms C and D, respectively). An independent Data Monitoring Committee approved release of these results.
Results: 445 pts were enrolled: 223 randomized to Arm A and 222 to Arm B. Median age was 65 yrs. Serious adverse event data based on expedited reporting (AdEERS) is available on all pts (see table). Common adverse events of Grade 3 or higher were thromboembolism (18.4% in arm A vs 5.4% in Arm B), infection/pneumonia (18.8% vs 9.0%) and hyperglycemia (5.8% vs 1.8%). Incidence of any grade 4 or higher toxicity was 22.0% in Arm A vs 12.6% in Arm B. Response data is being analyzed.
Conclusions: Lenalidomide plus two different schedules of Dex was investigated in this phase III trial. Preliminary results suggest that toxicity rates are higher in the high-dose Dex arm. The differences in the response rates between the two arms will dictate future trials and clinical practice.
Major Toxicties (AdEERS) Toxicity Arm A (n=223) Arm B (n=222) Cardiac ischemia (Grade &gt;=3) 2.7% 0.5% Hyperglycemia (Grade &gt;=3) 5.8% 1.8% Infection/Pneumonitis (Grade &gt;=3) 18.8% 9.0% Neuropathy (Grade &gt;=3) 0.9% 0.9% Thromboembolism (Grade &gt;=3) 18.4% 5.4% Any non-Hem toxicity (Grade &gt;=3) 53.4% 36.0% Any toxicity (Grade &gt;=4) 22.0% 12.6% Death (Grade 5) 4.5% 1.4%