bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interleukin-21-Induced Granzyme B-Expressing B Lymphocytes Infiltrate Tumors and Regulate T Cells
Authors: Lindner Stefanie , Dahlke Karen , Sontheimer Kai , Hagn Magdalena , Kaltenmeier Christof , Barth Thomas F.E. , Beyer Thamara , Reister Frank , Fabricius Dorit , Lotfi Ramin , Lunov Oleg , Nienhaus Ulrich , Simmet Thomas , Kreienberg Rolf , Moeller Peter , Schrezenmeier Hubert , Jahrsdörfer Bernd 
Published: October 2019

Abstract
Abstract 3278
The role of B cells in tumor infiltrations is controversial. Different studies suggest that certain tumor-infiltrating B cell populations exhibit regulatory potential. Here, we demonstrate that the microenvironment of various solid tumors contains granzyme B (GrB)-expressing B cells adjacent to IL-21-providing T cells. GrB-mediated effector T cell modulation is already known from regulatory T cells (Treg) and plasmacytoid dendritic cells. We now show that IL-21 induces B cells to express high levels of GrB and to modulate T cell proliferation by GrB-dependent degradation of the T cell receptor z-chain. Detailed characterization of IL-21-induced GrB+ B cells reveals a CD19+CD38+CD1d+CD147+ phenotype and expression of additional regulatory molecules including IL-10, IDO and CD25. Of note, GrB induction is accompanied by both BCR- and TLR-mediated signals and GrB expression levels are influenced by B cell expression of CD5. In summary, we demonstrate that IL-21 induces GrB-expressing regulatory B cells, which are detected in tumor infiltrations, and which may contribute to the modulation of cellular adaptive immune responses by Treg-like mechanisms. Our findings may stimulate the development of novel diagnostic and cell therapeutic approaches to the management of malignant, autoimmune and graft-versus-host pathologies.

Disclosures:
No relevant conflicts of interest to declare.
IL-35 Suppresses Lipopolysaccharide-Induced Endothelial Cell Activation Through Downregulation of MAPK Signaling-Mediated Upregulation of Adhesion Molecule VCAM-1
Authors: Sha Xiaojin , Meng Shu , Li Xinyuan , Pastrana Jahaira Lopez , Wang Hong , Yang Xiao-Feng 
Published: October 2019

Abstract
Abstract 3310
Our previous reports showed that survival/apoptosis of CD4+CD25+Foxp3+ regulatory T cells (Tregs) modulates vascular inflammation even though the mode of Tregs inhibition was unknown. Interleukin-35 (IL-35), consisting of two subunits Epstein-Barr virus–induced gene 3 (EBI3) and p35, is a novel anti-inflammatory cytokine, which is a member of the interleukin-12 (IL-12) cytokine family. IL-35 is produced by Tregs. It has been shown that IL-35 suppresses chronic inflammatory diseases such as asthma and inflammatory bowel diseases. However, an important question of whether IL-35 can carry out Tregs suppression and inhibit endothelial cell (EC) activation in acute inflammation remained unknown. Here we found that IL-35 significantly inhibits lung neutrophil infiltration into the surrounding areas of bronchioles and alveolar space when induced by intraperitoneal injection of lipopolysaccharide (LPS) in wild type mice and EBI3-deficient mice. Furthermore, cremaster microvasculature study using intravital microscopy showed IL-35 significantly suppresses leukocyte adhesion to the vascular wall as well, suggesting IL-35 inhibition of endothelial activation. Mechanistically, IL-35 inhibited LPS-induced upregulation of adhesion molecules on human aortic endothelial cells, a marker of endothelial activation, including vascular cell adhesion molecule 1 (VCAM-1). IL-35 acted through new IL-35 dimeric receptors gp130 and IL-12Rβ2, and inhibited VCAM-1 promoter transcription in mitogen-activated protein kinase (MAPK)-mediated pathway. These results provide a novel insight on Tregs and IL-35 inhibition of vascular inflammation.

Disclosures:
No relevant conflicts of interest to declare.
Rituximab Does Not Prevent Relapse in Patients with Thrombotic Thrombocytopenic Purpura
Authors: Jatinder Goyal , Lima Jose L. O. , Adamski Jill , Marques Marisa 
Published: October 2019

Abstract
Abstract 3318

Objective:
In the last decade, rituximab has been added to therapeutic plasma exchange (TPE) to treat patients with thrombotic thrombocytopenic purpura (TTP) who appear resistant to TPE. We sought to determine first if rituximab prevented TTP relapse. In addition, if relapse has occurred, we compared the rates of relapse of patients treated with TPE alone with those treated with a combination of TPE and rituximab.

Methods:
We retrospectively reviewed the medical records of all adult patients treated for TTP between 2003 and 2008 at our institution. TTP was defined as thrombocytopenia, hemolytic anemia and ADAMTS13 activity less than 10% due to an inhibitor. None of the patients had congenital TTP. Patient demographics, laboratory data, treatment characteristics and follow up details were collected from their electronic and apheresis' medical records. Kaplan-Meier curves were drawn for survival and Cox proportional hazards models were applied to look for independent predictors of relapse-free survival (RFS).

Results:
A total of 20 patients underwent TPE only (Group 1) as compared to 18 patients who also received rituximab during admission with TTP (Group 2). Table 1 shows that both groups were balanced at baseline for demographic and laboratory data. However, patients in group 2 had longer duration of hospital stay (p<0.0001), underwent more TPE procedures (p<0.0001) and took longer to achieve remission (p<0.0001). The mean follow up in group 1 was 77.5 (±22.4) months and in group 2 was 68.6 (±28.5) months. At follow-up, 5 patients from group 1 relapsed (25%) as compared with 6 patients from group 2 (35%) (p=0.50). The 1-year, 3-year and 5-year RFS rates were 95%, 85% and 74% for group 1, and 94%, 76% and 71%, respectively, for group 2 (p=0.53 using log rank test). On univariate analysis, only age at the time of treatment (p=0.05) and duration of follow-up after treatment (p=0.03) were predictors of relapse. However, on multivariate analysis, no independent predictors of relapse were identified.

Conclusion:
Rituximab does not prevent or reduce rates of relapse when used with TPE in patients with TTP. Since rituximab was added to patients later in their TPE course due to delayed response to treatment, it may yet have a role in decreasing the number of TPEs needed to achieve a response if it were started earlier during hospitalization for TTP.

Disclosures:
No relevant conflicts of interest to declare.
Thrombophilia Effect On Periprocedural Thromboembolism and Bleeding in Chronically Anticoagulated Patients
Authors: Wysokinska Ewa M. , McBane Robert D , Wysokinski Waldemar E , Slusser Joshua , Hodge David O , Heit John A 
Published: October 2019

Abstract
Abstract 3404

Background:
Appropriate periprocedural management of the chronically-anticoagulated patient with an inherited or acquired thrombophilia is uncertain.

Objective:
To estimate the 3-month cumulative incidence of thromboembolism (TE) and major bleeding and test thrombophilia as a potential predictor of these outcomes among chronically-anticoagulated patients undergoing a procedure.

Methods:
2182 consecutive patients referred to the Mayo Thrombophilia Center for standardized peri-procedural anticoagulation management were followed for TE, major bleeding and survival. The three-month cumulative incidence rates for TE, major bleeding and death were estimated by Kaplan-Meier analyses. For each chronic anticoagulation indication, we tested “strong” thrombophilia (antithrombin, protein C or protein S deficiency, homozygous or combined heterozygous Factor V Leiden or prothrombin G20210A), ”weak” thrombophilia (heterozygous Factor V Leiden or prothrombin G20210A), lupus anticoagulant/antiphospholipid antibodies and bridging heparin as potential predictors of TE and major bleeding using Cox proportional hazards modeling.

Results:
Patients with thrombophilia tended to be younger with a slight female predominance. Compared to no thrombophilia, thrombophilia patients (n=202; 143 bridged with heparin) had similar rates of venous (0% vs. 0.5%; p=0.34) and arterial (0.5% vs. 0.5%; p=0.94) thromboembolism, major bleeding (2.0% vs. 2.0%; p=0.97) and mortality (1.5% vs. 2.2%; p=0.52). Among thrombophilia patients, the TE and major bleeding rates were similar for strong (n=29) or weak thrombophilia (n=99), or lupus anticoagulant/antiphospholipid antibodies (n=74). Similarly, among thrombophilia patients, bridging heparin did not affect the rates of major bleeding (2.1% vs. 1.7%; p=0.85) or TE (0.7% vs. 0%, p=0.52).

Conclusions:
Inherited or acquired thrombophilia does not appear to impact the rates of TE, major bleeding or mortality after temporary interruption of chronic anticoagulation for an invasive procedure.

Disclosures:
No relevant conflicts of interest to declare.
Cluster Analysis Followed by Network Meta-Analysis to Compare Efficacy and Safety of Dabigatran, Rivaroxaban and Apixaban After Elective Total Knee and Hip Replacement Surgery
Authors: Harenberg Job , Marx Svetlana , Zolfaghari Shabnam , Weiss Christel , Wehling Martin , Schulze Astrid , Dahl Ola E 
Published: October 2019

Abstract
Abstract 3409
The new oral anticoagulant (NOAC) regimens (dabigatran 150mg od (D150) and 220mg od (D220), rivaroxaban 10mg od (R10), and apixaban 2.5mg bid (A5) have shown equivalent or superior efficacy and safety vs enoxaparin regimens for prevention of venous thromboembolism (VTE) following elective total knee (TKR) or hip replacement (THR) surgery. Due to a lack of head to head trials a network meta-analysis (NMA) may give information on a comparison between NOACs.
Studies comparing a NOAC with low-molecular-weight heparin for prevention of VTE following TKR and THR were included into the following set of analyses. First, a cluster analysis was performed to identify homogenous groups. Second, only homogeneous studies regarding each endpoint (VTE and VTE related death, major bleeding, and mortality) were included into a meta-analysis for each NOAC regimen. The odds ratio (OR) and 95% confidence interval (CI) were calculated for each NOAC program versus the comparator. Third, these OR and 95% CI were used for the NMA comparing the 4 treatment regimens.
First, cluster analysis identified duration of treatment (10+5 and 32+5 days) as the only measure for obtaining homogeneity of trials for every NOAC on every endpoint at 10+5 and 32+5 days (p>0.05) except for A5 and VTE over 10+5 days (analysis not performed). Third, the results of the NMA of the OR and 95% CI of the 4 NOAC regimens over 10+5 days were: D150 and D220 not different on any endpoint; D150 and D220 inferior to R10 for VTE (p<0.01, p<0.001); A5 trend for less major bleeding than R10 (p=0.0546); no differences for the other indirect comparisons. Results for 32+5 days were: D150 and D220 not different on any endpoint; D150 and D220 inferior to R10 VTE (p<0.001, p=0.0015) and to A5 for VTE (p<0.001, p<0001); R10 and A5 not different on VTE. Comparisons of major bleeding and mortality were not different.
The lack of a standard definition of VTE and bleeding outcomes between and sometimes within the studies of the NOACs substantially reduce the number of homogenous studies for inclusion into the present NMA using cluster analysis. The differences may help doctors and patients to decide the optimal treatment regimen for individual patient groups.

Disclosures:
No relevant conflicts of interest to declare.
BCOR Is Involved in Myeloid Cell Growth Control by Regulating Hox Genes
Authors: Cao Qi , Gery Sigal , Shojaee Seyedmehdi , Gearhart Micah , Bardwell Vivian , Muschen Markus , Koeffler H. Phillip 
Published: October 2019

Abstract
Abstract 3445
BCOR interacts with Polycomb group (PcG) proteins to form a PRC1-like transcriptional repressive complex. BCOR is an essential developmental regulator: hemizygous mutation of BCOR in males causes gestational lethality, and heterozygous mutation in females causes the X-linked developmental disorder Oculofaciocardiodental syndrome (OFCD). Studies in humans, cell lines and mice indicate that BCOR plays key roles in the regulation of early embryonic development, mesenchymal stem cell function and hematopoiesis. Recently, recurrent somatic BCOR mutations have been reported in retinoblastoma, medulloblastoma and acute myelogenous leukaemia (AML) suggesting BCOR functions as a tumor suppressor protein. The goal of the current study was to begin elucidating the function of BCOR in normal hematopoiesis and in hematopoietic transformation. To examine this in the mouse we transduced bone marrow (BM) from mice harboring a conditional Bcor deletion allele (BcorFl/Y) with lentivirus expressing CRE. FACS analysis showed that with CRE, 83% of Bcor-/Y (Bcor KO) BM cells kept in IL3, IL6 and stem cell factor (SCF) were CD34+ compared to 95% of non-induced BcorFl/Y (Bcor WT) BM cells. Moreover, following G-CSF treatment, Bcor KO BM cells showed a much higher incidence of cell differentiation (40.5%) compared to Bcor WT cells (5.4%) as shown by CD11b/Gr-1 FACS analysis. Surprisingly, Bcor KO BM cells also showed significantly higher proliferation rates in liquid culture and methycellulose colony assays. To identify BCOR downstream target genes, we compared the gene expression profiles between Bcor KO and WT BM cells. Real-time-PCR of individual Hox genes confirmed the upregulation of HoxA5, HoxA7 and HoxA9 in Bcor KO BM cells, which are known to increase self-renewal of immature hematopoietic cells. In addition, ChIP analysis showed specific binding of BCOR to HoxA7 promoter. In conclusion, our results from mouse experiments suggest that BCOR is involved in maintaining the CD34+ stem cell state and loss of BCOR leads to enhanced myeloid cell differentiation and proliferation possibly by regulating Hox genes. In addition, we examined BCOR expression levels in a large panel of human leukemic cell lines; high level BCOR mRNA and protein were detected in most cell lines. Notably, 2 cell lines, U937 and HL60, had low levels of BCOR mRNA and no detectable BCOR protein. Treatment of both cell lines with the differentiation inducers ATRA, Vitamin D3 or DMSO lead to a mark induction in BCOR expression both at the mRNA and protein level, suggesting that BCOR may be involved in myeloid cell differentiation. Further investigation should shed more light on the roles BCOR that plays in normal hematopoiesis and whether BCOR loss later in hematopoiesis could result in a differentiation block.

Disclosures:
No relevant conflicts of interest to declare.
Overexpression of Sharp-1 in MLL-AF6-Positive Acute Myeloid Leukemia
Authors: Kawasaki Akira , Taneja Reshma , Delwel Ruud , Tenen Daniel G. 
Published: October 2019

Abstract
Abstract 3493
Patients with acute myeloid leukemia (AML) carry various chromosomal translocations and/or mutations. Although t(6;11)(q27;q23) is observed in only less than 0.5 % of adult AML patients, this translocation is reported to be one of the independent poor prognostic factors in AML. This translocation induces expression of MLL-AF6 fusion protein, but the precise mechanism of leukemogenesis by MLL-AF6 has not yet been elucidated compared to other MLL fusion proteins. During the analysis of gene expression profiling of >500 AML patients registered in Erasmus University Medical Center in Rotterdam, we happened to find that all of five patients carrying t(6;11) translocation exhibited overexpression of Sharp-1/Dec2, which is involved in the circadian rhythm. AML cell lines carrying this translocation, ML-2 and CTS, also showed more than 10-fold upregulation of Sharp-1 expression. Knockdown of MLL-AF6 expression to 10 % in ML-2 cells by shRNA suppressed expression of Sharp-1 to less than 1 % through the change in the methylation status of histone H3 lysine residues in the Sharp-1 gene promoter region confirmed by chromatin immunoprecipitation. In addition, this knockdown induced growth suppression of ML-2 cells to 40–50 %. Proliferation of ML-2 cells was also suppressed by the knockdown of Sharp-1. Growth suppression of ML-2 cells is neither due to increased apoptosis nor increased differentiation, but due to increased number of cells undergoing cellular senescence together with the upregulation of p21. Furthermore, exogenous expression of Sharp-1 in murine bone marrow cells induced the proliferation of myeloid cells with the reduction of lymphoid cells in the bone marrow transplantation model. These results suggested that Sharp-1 plays a crucial role in the pathogenesis of AML with t(6;11)(q27;q23) and that targeting of Sharp-1 in leukemic stem cells would be a novel therapy for this poor outcome AML.

Disclosures:
No relevant conflicts of interest to declare.
Bcr-Abl Represses IRF8 Gene Transcription in a Stat5-Dependent Manner
Authors: Hjort Elizabeth , Huang Weiqi , Eklund Elizabeth A. 
Published: October 2019

Abstract
Abstract 3497
The interferon consensus sequence binding protein is a member of the interferon regulatory factor family of transcription factors (referred to as Icsbp or Irf8). The first described functions for Icsbp involved regulation of phagocyte and B-cell effector genes, including genes encoding components of the phagocyte NADPH-oxidase, Toll-like receptors and interleukin receptors. However, subsequent studies in murine models and human disease indicated that Icsbp also functions as a myeloid leukemia suppressor. For example, decreased Icsbp expression is found in chronic myeloid leukemia (CML) in association with uncontrolled disease, drug resistance and progression to blast crisis (BC). Decreased Icsbp expression is also found in the bone marrow of subjects with some subtypes of acute myeloid leukemia (AML). Consistent with this clinical correlative data, IRF8−/− mice exhibit a myeloproliferative neoplasm that is similar to CML and progresses to BC over time. However, the mechanism for decreased Icsbp expression in leukemia is not known, although preliminary studies indicate that DNA-methylation of the IRF8 locus is not altered. Therefore, in these studies, we investigate the effects of Bcr-abl on IRF8 transcription. This is clinically relevant, because previous studies in our laboratory identified a set of Icsbp-target-genes that contribute to the pathogenesis of CML. We find that Bcr-abl decreases expression of Icsbp mRNA and protein in a kinase dependent manner. Since it is unlikely that Bcr-abl directly binds to the promoter to regulate gene transcription, we hypothesized that Bcr-abl regulates IRF8 through an intermediary transcription factor. In this study, we determine that Stat5 negatively regulates IRF8 transcription through a proximal promoter cis-element. We also find that Stat5 repression activity is necessary for Bcr-abl dependent regulation of IRF8. Bcr-abl is known to phosphorylate and activate Stat5 in CML. In our studies, we find that Stat5 protein (but not mRNA) is also increased in Bcr-abl+ cells. Stat5 is a known substrate for calpain; a serine protease. We previously demonstrated that Icsbp regulates calpain protease activity through repression of the gene encoding Gas2; an endogenous calpain inhibitor. Consistent with this, our current studies demonstrate that Stat5 protein stability is increased in Bcr-abl+ cells in an Icsbp/Gas2/calpain-dependent manner. These results identify novel mechanisms by which Bcr-abl-kinase activity controls a positive feedback loop that leads to decreased Icsbp expression and stabilization of Stat5 protein. These studies suggest that targeting Gas2/calpain might be a novel therapeutic approach to CML.

Disclosures:
No relevant conflicts of interest to declare.
Curcumin Potentiates Antitumor Activity of Imatinib Via Inhibition of the AKT/mTOR Signaling Pathway and Down-Regulation of Bcr-Abl Gene in Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia
Authors: Gong Yuping , Guo Yong , Niu Ting 
Published: October 2019

Abstract
Abstract 3559
Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ALL) is triggered by constitutively activated BCR-ABL and SRC family tyrosine kinases. They interact each other, then activate downstream growth-signaling pathways including Raf/MEK/ERK,Akt/mTOR and STAT5 pathways. The BCR-ABL tyrosine kinase inhibitor imatinib is the standard treatment for Ph+ leukemia. However, response rate of Ph+ ALL to imatinib is low, relapse is frequent and quick. Studies have documented the potential anti-tumor activities of curcumin, a yellow colored polyphenol from the perennial herb Curcuma longa. However, whether curcumin can be used in the therapy for Ph+ALL remains obscure. Here, we reported that curcumin induced autophagic cell death by activating RAF/MEK/ERK pathway in early stage of the 24-hour exposure course, later induced apoptosis by inhibiting AKT/mTOR, ABL/STAT5 signalings, down-regulating expression of bcr/abl gene and Bcl2 anti-apoptosis protein, and up-regulating the expression of pro-apoptosis protein BAX in Ph+ALL cell line SUP-B15. Furthermore, we found curcumin exerted synergetic anti-leukemia effect with imatinib by inhibiting imatinib-mediated up-regulation of the activation of AKT/mTOR signaling and down-regulating expression of bcr/abl gene. It is worth noting that curcumin provide advantages over dexmethasone as to synergetic anti-leukemia effect with imatinib because dexmethasone improved the imatinib-mediated up-regulation of the activation of AKT/mTOR/P70S6 signaling. In primary samples from Ph+ALL patients, curcumin inhibit growth signaling not only in newly-diagnosised patient but also in imatinib-resistant patient. Moreover, curcumin effectively exhibited anti-leukemia efficacy and synergetic anti-leukemia effect with imatinib in Ph+ALL mouse models. These results demonstrate that curcumin may be a promising agent for the treatment of patients with Ph+ ALL, and curcumin might be particularly effective when used with current induction regimens consisting of imatinib with or without chemotherapy for treating Ph+ ALL. [Grant Support:National Natural Science Foundation of China (No.30770912), Foundation of the Science & Technology Department of Sichuan Province (No.2008SZ0017)].

Disclosures:
No relevant conflicts of interest to declare.