bluuebunny/crossref_metadata_2025_split huggingface dataset:
Plasma Protease-Mediated Metabolism of Carfilzomib and Its Implications on Clinical Effects and Side Effects
Authors: Tristan Sissung M , Peer Cody J , Korde Neha , Nehal Lakhani , Sham Malinkody , Landgren Ola , Figg William D 
Published: October 2019

Abstract
Introduction: Similar to most other anti-cancer drugs, carfilzomib is administered at a defined dose per m2. Inspired by preclinical data showing that extrahepatic peptidases play an important role in the metabolism of carfilzomib, using samples from a prospective clinical trial, we conducted an investigation focusing on concentrations of albumin in peripheral blood and its effects on plasma protease-mediated metabolism of carfilzomib.
Methods: Baseline laboratory values, pharmacokinetics data, and response data were collected from the clinical trial. Minimal residual disease was determined by multi-parametric flow cytometry utilizing, 8-color flow panel and analyzes ≥ 3 x 106 events (sensitivity 1 x 10-5). To study the rate of metabolism in plasma, apheresis samples were obtained from the NIH blood bank, lyophilized albumin was added to plasma with and without a non-specific protease inhibitor cocktail (1X). Carfilzomib concentrations were obtained at several time points over the course of 24 hours by mass spectrometry via previously published methods.
Results: Patients with baseline serum albumin >4.0 g/dL had a near 4-fold greater clearance (1576 L/h vs 401.1 L/h; n=9 vs n=34) that was further increased in patients with normal white blood cell count. Consistent with the increase in clearance, 80% of patients (29/33) with albumin <4.0 g/dL became minimum residual disease (MRD) negative whereas only 44.4% of patients (4/9) with albumin >4.0 g/dL had a similar outcome. Therefore, individuals with baseline albumin >4.0 g/dL are at significantly greater risk for not responding to the combination of carfilzomib, lenalidomide, and dexamethasone [OR (95%CI) = 7.3 (1.4-36.7); P=0.0049]. Median progression-free survival was also longer in patients with albumin <4.0 g/dL vs. albumin >4.0 g/dL (unreached vs. 18.8 months; P=0.0002). A trend between albumin and lymphopenia was also detected (P=0.17). The addition of 1.0 g/dL albumin increased the ex vivo proteolytic rate of carfilzomib in apheresis plasma from healthy individuals (74% vs 57.2% unreacted carfilzomib after 24 hours at 37°C), and the addition of a non-specific protease inhibitor reduced carfilzomib metabolism in plasma
Conclusions: Although they have lower grade myeloma, patients with albumin >4.0 g/dL, surprisingly, are at greater risk at having worse clinical outcomes to carfilzomib therapy; this finding appears to depend upon the ability of albumin to directly potentiate plasma protease-mediated metabolism of carfilzomib. Therefore, dose adjustments or concomitant therapy with protease inhibitors may be warranted in such patients. Efforts are underway to identify specific proteases that metabolize carfilzomib and determine potential inhibitors that may be clinically useful.

Disclosures
No relevant conflicts of interest to declare.
Two-Track Epigenetic Remodeling and Backtracking to Embryonic Stem Cell Bivalency in B-Cell Acute Lymphoblastic Leukemias
Authors: Lee Seung-Tae , Muench Marcus O. , Fomin Marina , Xiao Jianqiao , Zhou Mi , de Smith Adam J. , Martín-Subero José , Heath Simon , Houseman E. Andres , Roy Ritu , Wrensch Margaret R. , Wiencke John K. , Metayer Catherine , Wiemels Joseph L. 
Published: October 2019

Abstract
Purpose: We sought to define the drivers and functional consequences of DNA methylation changes in childhood pre-B cell leukemia. A comprehensive analysis of such DNA methylation changes will reveal aspects of the etiology and pathogenesis of leukemias, and suggest potential therapeutic modalities.
Background: The epigenome is extensively altered in carcinogenesis, but the proximate causes, functional consequences, and overall patterning of DNA methylation changes in the pediatric leukemias is not well defined.
Methods: We bisulfite sequenced at single base pair resolution two common pre-B cell leukemia case DNAs and a pre-B cell control (CD19+/CD34+ pre-B cells from normal marrow), and analyzed DNA methylation by high definition microarray in another 227 subjects. RNA expression was available for 82 samples, including the sequenced pre-B cells and leukemias.
Results: Epigenetic alteration of B-ALLs occurred in two tracks: de novo methylation of small functional compartments and demethylation of large inter-compartmental backbones. The de novo methylation occurred preferentially at polycomb targets and binding sites for the transcriptional co-repressor CtBP2. DNA methylation of ETV6-AML1 leukemia was overall equivalent to the control, with high hyperdiploid methylation levels being 4.4% lower. Hierarchical clustering revealed four groups, with ETV6-AML1 and hyperdiploid leukemias enriched within two separate groups. DNA methylation deviations were exaggerated in lamina-associated domains, with differences corresponding to these methylation clusters and/or cytogenetic groups. DNA methylation changes were correlated with gene expression changes, and a key polycomb expression signature was reversed when DNA methylation marks were pharmacologically removed in leukemia cell lines.
Discussion: While leukemia cells retain the majority of their developmentally determined DNA methylation patterns, key modifications with leukemogenesis revealed both broad patterns and functional targets with some dependence on known characteristics of pre-B cell leukemias. Our data suggested a pivotal role of polycomb and CTBP2 in de novo methylation, which may be traced back to bivalency status of embryonic stem cells. Driven by these potent epigenetic modulations, suppression of polycomb target genes was observed along with disruption of developmental fate and cell cycle and mismatch repair pathways and altered activities of key upstream regulators. An appreciation and validation of the observed changes will lead to new insights into etiology, pathogenesis, and treatments of childhood ALL.

Disclosures
No relevant conflicts of interest to declare.
Rituximab May be Not Suitable for Epstein Barr Virus-Induced Hemophagocytic Lymphohistiocytosis in Chinese
Authors: Wang Zhao , Wang Yini , Wei Na , Zeng Xiangzong , Huang Wenqiu , Wang Jingshi 
Published: October 2019

Abstract
Purpose: Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening hyperinflammatory syndrome. Epstein-Barr virus (EBV) is the most frequent infection associated with HLH. Some studies revealed that rituximab containing regimens is an effective treatment for EBV- HLH. But we didn’t make the similar observation in Chinese adult patients. This study was aim to describe the outcomes and tried to explain the possible causes.
Methods: We performed an investigation involving 46 EBV-HLH patients. Eleven of them received treatment with rituximab plus HLH-94 protocol. The other 35 patients were only treated with HLH-94 protocol. The EBV-DNA load and survive rate of patients were used to evaluated curative effective. We identified the lineage of EBV-infected cell by immunohistochemistry (ICH) in combination with in site hybridization (ISH) in Epstein-barr Virus Encoded Rnas (EBER) for cell type-specific markers.
Result: The eleven patients received 3 rituximab infusions on average (range 2-4) at a dosage of 375mg/m2 every week. We found no significant difference in EBV-DNA load between the rituximab containing regimens group and conventional HLH-94 group at diagnosis (median load was 3.2×105copies/ml vs 2.8×105copies/ml) and 4 weeks after therapy (median load 6.4×103copies/ml vs 5.5×103copies/ml). The survive rates of the two groups on 2 months, 6 months and 12 months respectively were 45.5% vs 42.9%, 27.3% vs 28.6%, 18.2% vs 20.0%. The pathological examination of tissue biopsy in the patients from rituximab containing regimens group revealed that EBER was positive in all patients. We identified the lineage of EBV-infected cell by double staining——ICH in combination with ISH. Nine of them were CD3+/EBER+, and only two of them were CD20+/EBER+.
Conclusion: It suggested that rituximab may be not suitable for EBV-HLH patients in China. Most probably, EBV predominantly infects T cells in Chinese, which could explain the nonsuperiority of rituximab in Chinese adult EBV-HLH. It is necessary to make further research to demonstrate it.

Disclosures
No relevant conflicts of interest to declare.
The Tetraspanin CD81 Facilitates Tumor Metastasis By Modulating Immune Suppression
Authors: Vences Catalan Felipe , Rajapaksa Ranjani , Srivastava Minu K. , Marabelle Aurelien , Levy Shoshana 
Published: October 2019

Abstract
Tumor metastasis is the major cause of cancer mortality. While immune cells are aimed at halting metastases, the proliferating cancer cells at the primary tumor site recruit cells that counteract the adaptive anti-tumor immune response. Indeed, it is well established that tumors induce the accumulation and proliferation of immune suppressive cells, such as regulatory T cells (Tregs) and Myeloid Derived Suppressor cells (MDSC).
The tetraspanin CD81 belongs to a family of proteins that play an important role in the immune system as evident by impaired immune functions of DCs, B and T cells in several tetraspanin-deficient mice (CD37, CD81, CD151, and CD82).
While many studies have addressed the function of CD81 in infection and in the immune system, few have focused on its role in tumorigenesis and metastasis. Here we report that the growth of subcutaneously implanted breast cancer tumors (4T1) is slightly impaired in CD81 knockout (CD81KO) compared to wild type mice. Moreover, CD81KO mice develop very few lung metastases compared to their wild type and heterozygous counterparts.
Both wild type and CD81KO tumor-bearing mice show substantial increases in Tregs, and MDSCs. However, these Tregs and MDSCs differ functionally - those derived from wild type mice are effective suppressors of T cell proliferation. By contrast, Tregs and MDSCs derived from tumor-bearing CD81KO mice do not suppress the proliferation of Teff cells. Thus, it is highly likely that while Teff cells are greatly restrained by Tregs and MDSCs in wild type tumor-bearing mice, the impairment of both suppressive cell populations in CD81KO mice enables the anti-tumor function thereby opposing metastases.
Figure 1 Figure 1.

Disclosures
No relevant conflicts of interest to declare.
Clots from FXI-Deficient Patients Display a Reduced Fibrinolytic Resistance
Authors: Peyvandi Flora , Cannavò Antonino , Incampo Francesca , Menegatti Marzia , Semeraro Nicola , Biguzzi Eugenia , Siboni Simona Maria , Colucci Mario 
Published: October 2019

Abstract
Factor XI deficiency (FXI-Def) is associated with mild, unpredictable bleeding tendency. FXI is believed to participate in a thrombin-dependent positive feed-back that leads to the formation of a second burst of thrombin, which, in turn, inhibits fibrinolysis mainly through TAFI activation. It is conceivable, therefore, that FXI-Def leads to the formation of clots that are more susceptible to lysis. Our study was undertaken to test this hypothesis.
Eighteen subjects with FXI-Def (1-58%), and 17 matched controls were studied. All assays were performed on citrate-plasma stored at -80°C.
The fibrinolytic resistance to t-PA (30 ng/ml) of clots generated by 0.5 pM tissue factor was lower in samples from FXI-Def subjects than in controls (lysis time: 61.1 ± 9.7 vs 74.9 ± 14.9 min, P=0.008). Generation of thrombin and TAFIa during fibrinolysis was markedly reduced in FXI-Def samples (<0.0005) and TAFIa10min was significantly correlated with lysis time (rho=0.56, P=0.01). Furthermore, enhancement of TAFI activation by thrombomodulin increased fibrinolytic resistance to normal. However, neutralization of TAFIa by PTCI did not abolish the difference between the two groups, suggesting that both TAFI-dependent and TAFI-independent mechanisms concurred to enhance the lysability of FXI-Def clots. Several findings suggest that FXI-Def is not the main cause of hastened fibrinolysis: 1) lysis time did not correlate with FXI level; 2) a significant difference in fibrinolytic resistance between FXI-Def and controls was observed under conditions that bypassed FXI activation (clots induced by thrombin+CaCl2+FXa-inhibitor or by a 100-fold higher concentration of tissue factor) or after normalization of FXI levels by addition of purified FXI. In conclusion, bleeding in FXI-Def may result from premature lysis of the haemostatic plug, which ensues because of little TAFI activation and other unidentified mechanisms. Moreover, it appears that FXI-Def is not part of the causal pathway leading to hastened fibrinolysis but rather a bystander.

Disclosures
Peyvandi: NovoNordisk: Research Funding, speaker's fee Other; CSL Behring: speaker's fee, speaker's fee Other; LFB: speker's fee, speker's fee Other; Grifols: speaker's fee, speaker's fee Other; Bayer: speaker's fee Other; Baxter: speaker's fee Other; Biotest: Research Funding; Kedrion biopharma: Research Funding. Colucci:Boehringer Ingelheim : Research Funding.
A Systems Biology Model for the Coagulation Network in Non-Bleeding State Describes Baseline Activity of Coagulation
Authors: Lee Dooyoung , Nayak Satyaprakash , Pittman Debra , Arkin Steven , Martin Steven , Heatherington Anne C , Vicini Paolo , Hua Fei 
Published: October 2019

Abstract
Coagulation is a process crucial to stop bleeding from a damaged vessel. The network is comprised of a complex interplay of various pro-coagulant and anti-coagulant factors. Several systems models for the coagulation pathway have been published, as a way to investigate the pathway complexity. Most published models describe the thrombin generation profile (TGA) or prothrombin time (PT) following extrinsic pathway activation by tissue factor, or activated partial prothrombin time (aPTT) through activation of the intrinsic pathway by contact activation. In the clinical setting, thrombin-anti-thrombin complex (TAT) and prothrombin fragment 1+2 (PF1+2) are often used as biomarkers for in vivo coagulation activity in the non-bleeding state. Even in the absence of any treatment, there are detectable levels of PF1+2 and TAT in healthy volunteers indicating low level coagulation activity exists in the normal baseline, non-bleeding state. In this study, we developed a mathematical model for coagulation to describe the baseline activity of PF1+2 and TAT. We then used the model to understand the impact of the coagulation pathway activity during non-bleeding state on thrombin generation activated by tissue factor.
First, a coagulation model from Hockin et al. (J Biol Chem. 2002;277(21):18322-33) was modified to describe internally generated data for thrombin generation and aPTT modulation following addition of various concentrations of recombinant factor VIIa or plasma derived factor Xa to normal or hemophilic human plasma. Next, protein synthesis and degradation were incorporated into the model and platelet-dependent reactions were tuned down to describe the baseline coagulation activity in non-bleeding healthy subjects. Using a simulated annealing algorithm, the new parameters were optimized to fit published data for PF1+2 and TAT in healthy volunteers and changes of PF1+2 following treatment with eptacog alfa (recombinant factor VIIa). In the model, the baseline coagulation activities can be described by a very low level of tissue factor, which is much lower than the detection limit of a regular ELISA method. Using this baseline model, we tested the effect of this baseline coagulation activity on tissue factor-activated thrombin generation, and found that very small baseline levels of activated enzymes significantly shorten the lag time of thrombin generation, but did not affect the peak thrombin. We also performed a global sensitivity analysis to identify key proteins in the coagulation network whose modulation will have the biggest impact on PF1+2 and TAT levels.

Disclosures
Lee: Pfizer Inc.: Employment. Nayak:Pfizer Inc.: Employment. Pittman:Pfizer Inc.: Employment. Arkin:Pfizer Inc.: Employment. Martin:Pfizer Inc.: Employment. Heatherington:Pfizer Inc.: Employment. Vicini:Pfizer Inc.: Employment. Hua:Pfizer Inc: Employment.
Outcomes of Central Venous Catheter Associated Upper Extremity Deep Vein Thrombosis in Cancer Patents
Authors: Delluc Aurelien , Le Gal Gregoire , Scarvelis Dimitrios , Carrier Marc 
Published: October 2019

Abstract

Introduction: Upper extremity deep vein thrombosis (UEDVT) is a frequent complication of central venous catheters in cancer patients. Anticoagulation with low molecular weight heparin (LMWH) for a minimum of 3 months is the currently recommended treatment for catheter-related UEDVT in cancer patients. Following catheter removal and a minimum of three months of anticoagulant therapy, the risk of recurrence of VTE is likely to be low and it might be reasonable to discontinue anticoagulant therapy. However, there are no data available to support these hypotheses. Therefore, we sought to assess the efficacy and safety of LMWH for the treatment of catheter-related UEDVT in cancer patients and determine the risk of recurrence of VTE after discontinuation of anticoagulation.
Material and methods: A retrospective single center cohort study including consecutive cancer outpatients assessed between July 2008 and December 2012 for the management of symptomatic central venous catheter associated proximal UEDVT was conducted.
Results: A total of 99 patients were included. Among them, 89 were treated with one month of full therapeutic weight-adjusted dose of LMWH followed by an intermediate dose. A prophylactic dose of LMWH was given after 3 (n=8), 6 (n=4), or 12 (n=1) months of intermediate dosing of LMWH. The remainder patients continued with intermediate dose of LMWH until discontinuation or last follow up. Median duration of anticoagulation was 124 days (range 40 to 1849). No recurrent VTE and two major bleeding episodes occurred during the first 3 months of treatment. Among the 13 patients who were receiving prophylactic doses of LMWH after completion of 3, 6 or 12 months at full and intermediate doses, 2 (15.4%) had a recurrent VTE event. Others did not recurred while on treatment.
Eighty-three patients discontinued anticoagulation and 80 could be followed-up after anticoagulation discontinuation for a median of 632 days (range 6 to 2495). Central venous line was pulled out in 77 patients (96.2%). Five recurrences were observed during follow up. The cumulative probability of recurrent VTE was higher in patients whose cancer was active at the time of anticoagulation discontinuation as compared with those in remission (22.2% (95% CI: 0 to 40.6) vs. 2.3% (95% CI: 0 to 6.7)) (Figure 1).
Conclusion: LMWH can safely be used to treat catheter associated proximal UEDVT in the setting of cancer. In patients whose central venous line has been pulled and cancer is in remission, anticoagulation therapy can be safely discontinued.
Figure 1: cumulative probability of recurrence according to cancer status at the time of anticoagulation discontinuation

Disclosures
No relevant conflicts of interest to declare.
Transcription Activation of an Antisense Long Noncoding RNA (lnc-Mega1) of RBM15 By RUNX1 Enhances Megakaryocyte Differentiation
Authors: Zhao Xinyang , Tran Ngoc-Tung , Zhou Dewang , Su Hairui , Zhang Li , Townes Tim M. 
Published: October 2019

Abstract
RBM15 encodes an RNA binding protein, which regulates self-renewal and differentiation of hematopoietic stem cells. RBM15 knock-out promotes the proliferation of Mk progenitor cells but blocks the maturation of Mk progenitor cells as measured by polyploidy. RBM15-MKL1 fusion causes pediatric acute megakaryoblastic leukemia without Down’s syndrome. Here, we cloned a long non-coding RNA (we called Lnc-Mega1), which is transcribed in the opposite direction of the human RBM15 gene. Lnc-Mega1 is not transcribed in mice in the RBM15 locus. Blast search also indicates there are no homologues available in mouse. The 5’end of Lnc-Mega1 overlaps with the 5’ end of RBM15 transcript for 180bp. We found that RUNX1 binds to the promoter regions of RBM15 by chromatin immunoprecipitation assay. RUNX1 knock-down reduces the transcription of both RBM15 and Lnc-Mega1. Therefore, RUNX1 controls the transcription of both genes. Nevertheless, the promoter is not always bidirectional. We found in hematopoietic stem cell RBM15 is transcribed more actively than lnc-Mega1. During differentiation, both lnc-Mega-1 and RBM15 are transcribed actively. In addition, ectopic expression of Lnc-Mega1 enhances megakaryocyte differentiation in both leukemic cell lines and human CD34+ cord blood cells. The tertiary structure of the lnc-Mega1 is critical as truncations cannot expedite differentiation. Many genes important for hematopoiesis such as Pu.1, p21, and p53 contain anti-sense transcription, but the mechansims for antisense RNA molecules in regulating their sense counterparts are very different. Although RBM15 does not directly interact with lnc-Mega1, Lnc-Mega1 overexpression enhances the RBM15 protein level via increasing the translation efficiency. Given that RBM15-MKL1 is the causal protein in acute megakaryoblastic leukemia, lnc-Mega1 RNA might contribute to leukemogenesis by increasing the translation efficiency of the fusion protein.

Disclosures
Zhou: Univeristy of Alabama at Birmingham: Employment. Townes:University of Alabama at Birmingham: Employment.
Twist-1 Increases Hematopoietic Stem Cell Self-Renewal and Causes Myeloid Skewing
Authors: Ma Xiaotong , Dong Chengya , Liu Xiaoyan , Wang Nan , Wang Lina , Wang Jianxiang 
Published: October 2019

Abstract
Twist-1 protein belongs to the large family of basic Helix-Loop-Helix transcription factors with diverse physiological functions in mesoderm-derived tissues. Growing evidences now link Twist-1 to the acquisition of stem-cell-like properties. However, there is little information available regarding its expression pattern and functional role in the hematopoietic system. We analyzed Twist-1 expression patterns in different hematopoietic cell populations from normal mouse bone marrow, and found that Twist-1 was most highly expressed in long-term hematopoietic stem cells (LT-HSCs) but showed a low abundance in more differentiated descendants. To investigate Twist-1 gene function, retroviral-mediated overexpression or removal experiments were performed. Competitive repopulation studies demonstrated that enforced expression of Twist-1 in HSC-enriched Lin−c-Kit+Sca-1+ (LKS) cells resulted in an increase in the size of the G0 population, and in their reconstitution ability after the first and a second transplantation. Conversely, removal of Twist-1 in LKS cells impaired their ability to repopulate. In addition, increased Twist-1 expression caused a shift toward production of myeloid cells. Twist-1 transduction in LKS cells activated myeloid lineage-determining factors PU.1 and GATA-1 and down-regulated lymphoid factor GATA-3 in vitro, suggesting that Twist-1-mediated myeloid skewing occurs in hematopoietic stem and progenitor cells (HSPCs). These findings indicate that Twist-1 is not only involved in the maintenance of HSC dormancy and self-renewal capacity but also implicated in the myeloid lineage fate choice of HSPCs. Exploration of the underlying mechanisms revealed that Twist-1 overexpression lead to altered expression of Runx1/c-Mpl/Tie2 regulatory pathway, and quiescence-associated N-cadherin and Hes1 in LKS cells, which may contribute to the phenotypes observed in Twist-1-overexpressing mice. These studies shed additional light on the mechanisms involved in the maintenance of normal HSC and myeloid lineage differentiation, and may also provide clues to the mechanisms controlling pathogenesis and preservation of leukemic stem cells.

Disclosures
No relevant conflicts of interest to declare.