bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hodgkin's Disease and HIV Infection (HD-HIV): Prognostic Factors In 596 Patients (pts) within the European Group for the Study of HIV and Tumours (GECAT)
Authors: Spina Michele , Ribera Josep-Maria , Gabarre Jean , Wyen Christoph , Montoto Silvia , Jaeger Ulrich , Talamini Renato , Re Alessandro , Miralles Pilar , Tirelli Umberto 
Published: October 2019

Abstract
Abstract 3883

Background:
Hodgkin's disease (HD) is the most common non-AIDS defining tumour diagnosed in HIV setting. The introduction of highly active antiretroviral therapy (HAART) has opened a new prospective in the treatment of pts with HD-HIV as the better control of the underlying HIV infection allows the use of more aggressive chemotherapy regimens, including high dose chemotherapy. However, up to now prognostic factors on overall survival (OS) or time to treatment failure (TTF) have not been identified yet.

Methods:
in order to identify prognostic factors, we analyze data on 596 pts with HD-HIV diagnosed and treated in 90 different Institution from 6 European countries from October 1983 to March 2010. All factors were analyzed for OS and TTF.

Results:
86% of pts were male and the median CD4 cell count was 224/mL (range 3–1274); 52% of pts had mixed cellularity subtype, stages III-IV were diagnosed in 72% of cases and 55% of pts had extranodal involvement (bone marrow 35%, spleen 21%, liver 14%). Table 1 summarizes the results of multivariate analysis.

Conclusion:
We identified a new “European Score” (IPS>2 and CD4 cell count <200/mL) for HD-HIV able to predict different outcomes in these patients. This score should be considered for future prospective studies.

Disclosures:
No relevant conflicts of interest to declare.
MAZ Is a Substrate for the Deubiquitinating Enzyme DUB1
Authors: Kim Yong-Soo , Shin Dong-Mi , Wang Hongsheng , Morse Herbert 
Published: October 2019

Abstract
Abstract 3913
Ubiquitination is a fundamental mechanism of signal transduction that regulates immune responses and many other biological processes. Similar to phosphorylation, ubiquitination is a reversible process that is counter-regulated by ubiquitinating enzymes and deubiquitinating enzymes (DUBs).
DUB1 has been identified as a member of a subfamily of deubiquitinating enzymes that are induced by Interleukin-3 (IL-3) in Ba/F3 cells. Recently, we've known that DUB1 is expressed in some pro-B and pre-B cell lines and is differentially regulated during normal B cell differentiation with highest expression in small pre-B cells. To understand the functional role of DUB1 in early B cell development, we identified a transcription factor, MAZ, as an interacting partner or substrate of DUB1 in the Abelson-transformed 220-8 pro-B cell line by using a retrovirus-based protein-fragment complementation assay (RePCA) screen. MAZ has been identified as a critical regulator of p21 gene induction, which controls cell cycle progression in synovial fibroblast cells.
Immunoprecipitation and immunoblot analysis confirmed that MAZ and DUB1 interact with each other in cells. DUB1 expression significantly increased the steady-state cellular levels of MAZ. Notably, the half-life of MAZ in the pEGFP-DUB1-transfected cells was significantly increased by DUB1 expression, whereas the half-life of MAZ in the mock-transfected cells was less than 1 hr. These data therefore demonstrate that DUB1 specifically stabilizes MAZ in vivo.
We found that the overexpressed MAZ was polyubiquitinated and that the polyubiquitinated MAZ was the substrate for proteasome inhibitor MG132 caused a robust increase of MAZ polyubiquitination. Overexpression of DUB1 in 293T cells caused a decrease of MAZ polyubiquitination in a DUB1 dose-dependent manner. Taken together, these results indicate that DUB1 mediate the ubiquitination-dependent degradation of MAZ.
Other study shows that the DUB1 targets both K-48 and K-63 linked ubiquitination suggesting that it may be involved in both protein degradative and non-degradative functions during early B cell differentiation.

Disclosures:
No relevant conflicts of interest to declare.
Decitabine Is Effective and Safe In Patients with Chronic Myelomonocytic Leukemia
Authors: Jabbour Elias , Kantarjian Hagop M. , Ravandi Farhad , Cornelison A. Megan , Kadia Tapan , Borthakur Gautam , Cortes Jorge E. , Garcia-Manero Guillermo 
Published: October 2019

Abstract
Abstract 4032

Background:
Chronic myelomonocytic leukemia (CMML) is a rare yet indolent disease. The median survival duration in CMML is 12 to 18 months and patients with poor prognostic features do even worse, with median survival time ranging 3 to 6 months. Activity with decitabine in CMML has been previously reported. We sought to analyze the clinical experience of 17 adults with a diagnosis of CMML treated on two decitabine studies.

Methods:
A subset of patients with CMML from a pivotal phase III 3-day dosing and an open-label trial of 5-day dosing were identified and reviewed to determine the overall response rate (ORR, based on IWG 2006 criteria), duration of response, time to response, and overall survival (OS).

Results:
A total of 17 patients with CMML were included in this review. Mean age at diagnosis was 71 years (range, 47 to 81 years) with a mean time from diagnosis of 406.4 days. The majority of CMML patients had de novo (94.1%), good risk cytogenetics (58.8%) with an IPSS classification of Intermediate-1 (64.7%). Baseline mean white blood count (WBC), hemoglobin (HGB), and platelets (plts) were 7.5 × 103/μ L, 14.6 g/dL and 81.9 × 103/μ L, respectively. A larger proportion of CMML patients at baseline were plt and RBC transfusion independent. Objective response rate (ORR) was 41% [17.6% complete response (CR) and 23.5% marrowCR (mCR)]; Hematologic improvement (HI) was observed in 11.7% and stable disease in 29.4% of patients. Median survival was 391 (95% CI 239, 678) days and 2 (11.7%) patients progressed to AML. The adverse event profile was similar to observations in previous trials with myelosuppression and infectious complications.

Conclusions:
This retrospective review of responses in CMML patients supports previous findings of decitabine experience in this population. In this analysis an overall response rate of 41.4% was achieved. Decitabine provided anti-CMML activity with an acceptable safety profile.

Disclosures:
Jabbour: Eisai Inc.: Editorial and statistical support from Eisai Inc., Honoraria. Kantarjian:Novartis: Research Funding; Pfizer: Research Funding; Bristol Myers Squibb: Research Funding; Novartis: Consultancy. Ravandi:Eisai Inc.: Research Funding; Eisai Inc.: Honoraria. Borthakur:Eisai Inc.: Research Funding. Cortes:Novartis: Research Funding; Pfizer: Consultancy, Research Funding; Bristol Myers Squibb: Research Funding.
Interleukin-16 Is An Important Growth-Promoting Factor and a Novel Diagnostic and Therapeutic Target for Multiple Myeloma
Authors: Atanackovic Djordje , Hildebrandt York , Luetkens Tim , Zander Axel R. , Bokemeyer Carsten , Kroeger Nicolaus 
Published: October 2019

Abstract
Abstract 4056

Background:
Multiple myeloma (MM) is a malignancy characterized by the expansion of a plasma cell (PC) clone that localizes to the bone marrow (BM). Myeloma cells and BM stromal cells both produce soluble factors promoting the survival and progression of MM. Interleukin-(IL)-16 is involved in regulating migration and proliferation of normal leukocytes, however, it has been unclear whether IL-16 also plays a role in the pathophysiology of human cancers.

Methods:
Using an antibody array we screened supernatants of myeloma cell lines for the presence of a variety of cytokines/chemokines. We confirmed IL-16 expression in myeloma cell lines as well as in malignant PC and BM plasma from MM patients applying real-time PCR, western blots, ELISA, and flow cytometry. We applied inhibitory RNA to analyze IL-16 function and we used anti-IL-16 antibodies to evaluate possible therapeutic options for MM.

Results:
We found IL-16 to be strongly overexpressed in the BM of myeloma patients. Myeloma cell lines as well as primary tumor cells from MM patients constitutively expressed IL-16 RNA and protein and spontaneously secreted soluble IL-16. Functional analyses revealed that IL-16 supports the proliferation of myeloma cells. Accordingly, silencing of IL-16 expression had an anti-proliferative effect on the tumor cells. Most importantly, the application of a monoclonal antibody directed against IL-16had a strong growth-inhibiting influence on myeloma cells.

Conclusions:
These findings suggest that cytokine IL-16 is an important growth-promoting factor in MM and might represent a novel diagnostic and therapeutic target for this incurable human malignancy.

Disclosures:
No relevant conflicts of interest to declare.
Weak Sensitivity of Myeloma Cells to CD38 or CD138-ADCC
Authors: Clemenceau Beatrice , Vivien Regine , Descamps Géraldine , Maiga Sophie , Amiot Martine , Vié Henri , Pellat-Deceunynck Catherine 
Published: October 2019

Abstract
Abstract 4072
The development of novel treatments such as those based on human monoclonal antibodies (mAb) are currently being evaluated in preclinical and early clinical studies in cancers. There is convincing evidence supporting a key role for antibody-dependent cell-mediated cytotoxicity (ADCC) in the clinical response of several therapeutic monoclonal antibodies. In myeloma, CD38 and CD138, both highly expressed by all myeloma cells, represent the best targets for ADCC and humanized Abs are currently in development for both antigens. The aim of the present study was to assess the CD38 and CD138-ADCC sensitivity of a large panel of human myeloma cell lines (HMCLs) representative of the disease heterogeneity.
To reproductively assess ADCC, we used mouse FcgRIII expressing human T lymphocytes as cytotoxic effector cells. We measured ADCC sensitivity of 20 HMCLs with two mouse IgG1 anti-CD38 (clones T16 and HIT2), with two mouse IgG1 anti-CD138 (clones BB4 and MI15) and with a mouse IgG2a anti-HLA class-I (clone W6.32) by a standard 51Cr release assays performed at an effector to target ratio of 10:1.
Unexpectedly, despite high level of CD38, only 3 cells lines among 20 were sensitive to anti-CD38/ADCC. No correlation was observed between anti-CD38/ADCC sensibility and the CD38 expression level. No correlation was observed too between sensitivity and representative molecular heterogeneity of HMCLs. The absence anti-CD38/ADCC was not due to intrinsic resistance lysis through ADCC since these cell lines were lysed when using an anti-HLA class-I mAb (or anti-CD20 mAbs for one CD20+ HMCL). Furthermore, absence of ADCC was not due to antibody-induced antigenic modulation. Surprisingly too, none HMCL was lysed by anti-CD138 mAbs despite high expression of CD138. Moreover, primary myeloma cells purified from peripheral blood of a patient were also resistant to both anti-CD38 and anti-CD138 mAbs.
These results show that ADCC activity mediated by a particular monoclonal antibody varies according to the target cell and independently of the antigen expression level, suggesting that the antigen “environment” might affect the interactions between antibody, Fc receptor and effector cells. Further studies will be required to determine the CD38 and CD138 “environment” factors on myeloma cell that can influence ADCC.

Disclosures:
No relevant conflicts of interest to declare.
CREBBP Mutations In Relapsed Acute Lymphoblastic Leukemia
Authors: Mullighan Charles , Zhang Jinghui , Kasper Lawryn H. , Lerach Stephanie , Payne-Turner Debbie , Phillips Letha A , Collins-Underwood J. Racquel , Heatley Susan L. , Ma Jing , Buetow Kenneth , Pui Ching-Hon , Brindle Paul K. , Downing James R. 
Published: October 2019

Abstract
Abstract 413
Relapsed acute lymphoblastic leukemia (ALL) is a leading cause of death due to disease in young people, but the biologic determinants of treatment failure remain poorly understood. To identify novel sequence mutations contributing to relapsed in ALL, we resequenced 300 genes in matched diagnosis and relapse samples from 23 patients with ALL. The cohort included B-progenitor ALL with high hyperdiploidy (N=3), TCF3-PBX1 (N=1), ETV6-RUNX1 (N=3), rearrangement of MLL (N=3), BCR-ABL1 (N=3), and low hyperdiploid, pseudodiploid, or miscellaneous karyotypes (N=10). This identified 52 somatic non-synonymous mutations in 32 genes, many of which were novel, including mutations in the transcriptional coactivators CREBBP and NCOR1, the transcription factors ERG, SPI1, TCF4 and TCF7L2, components of the Ras signalling pathway, histone genes, genes involved in histone modification (CREBBP and CTCF), and genes previously shown to be targets of recurring DNA copy number alteration in ALL. Analysis of an extended cohort of 63 diagnosis-relapse cases and 200 acute leukaemia cases that did not relapse found that 19% of relapse cases had sequence or deletion mutations of CREBBP, which encodes the transcriptional coactivator and histone acetyltransferase (HAT) CREB-binding protein (CBP). The mutations were either present at diagnosis, acquired at relapse, or duplicated to homozygosity at the time of relapse. Moreover, several mutations acquired at relapse were detected in subclones at diagnosis, suggesting that the mutations confer a selective advantage and promote resistance to therapy. The mutations either resulted in truncated alleles or deleterious substitutions in highly conserved residues of the HAT domain. To examine the functional consequences of the mutations, we introduced wild type or mutant Crebbp alleles into Cbp/Ep300flox/flox murine embryonic fibroblasts, (dKO MEFs), and examined histone acetylation, expression of CREBBP target genes, and cellular proliferation. The HAT domain mutations resulted in impaired acetylation of the key Crebbp substrate, H3K18, and resulted in impaired transcriptional regulation of multiple CREBBP targets and pathways, including cAMP, dsRNA and dexamethasone responsive genes. The latter observation suggests that CREBBP mutations may directly result in resistance to corticosteroid therapy, which is a hallmark of high risk ALL. Together, these data these results extend the landscape of genetic alterations in leukemia, and identify mutations targeting transcriptional and epigenetic regulation as a mechanism of resistance in ALL.

Disclosures:
Pui: EUSA Pharma: Honoraria; Enzon: Honoraria; Sanofi-Aventis: Honoraria.
Immunomodulation of NK Cells through 4-1BB (CD137) to Improve the Anti-Lymphoma Activity of Rituximab: Antibody-Based Anti-Lymphoma Synergy
Authors: Kohrt Holbrook E , Houot Roch , Goldstein Matthew J , Weiskopf Kipp , Chao Mark , Chen Lieping , Tedder Thomas , Levy Ron 
Published: October 2019

Abstract
Abstract 422

Background:
Antibody-dependent cell-mediated cytotoxicity (ADCC), largely mediated by natural killer (NK) cells, is thought to play an important role in the efficacy of rituximab, an anti-CD20 monoclonal antibody (mAb) used to treat patients with B cell lymphomas. CD137 is a costimulatory molecule expressed on a variety of immune cells following activation, including NK cells. We hypothesized that the anti-lymphoma activity of rituximab could be enhanced by stimulation of NK cells with an anti-CD137 agonistic mAb.

Methods:
Rituximab induced upregulation of CD137 on NK cells was assessed using lymphoma cell lines and primary lymphoma patient samples. In-vitro NK cell degranulation and cytotoxicity were assessed by CD107a mobilization and chromium release. A murine lymphoma tumor model targeted by mouse anti-mouse CD20 mAb was used to assess in-vivo synergy of anti-CD20 and anti-CD137 mAbs. Mechanism of synergy was explored by T cell, NK cell, and macrophage depletion in the immune competent mouse model. A xenotransplant model in SCID mice with disseminated, luciferase-labeled lymphoma was used to demonstrate efficacy of anti-CD137 mAb and rituximab, and sufficiency of an innate immune response.

Results:
NK cells in human primary lymphoma samples do not express CD137 at baseline, however these cells highly upregulate CD137 when encountering rituximab-coated tumor B cells. Rituximab-induced NK cell degranulation and cytotoxicity as measured by CD107a mobilization (p=.006) and chromium release (p=.01) are enhanced by anti-CD137 agonistic mAb. In a murine lymphoma model, anti-CD137 mAb significantly enhances anti-tumor activity of anti-CD20 mAb leading to complete tumor resolution (p<.001) and prolonged survival (p=.048). Sequential administration of anti-CD20 mAb followed by anti-CD137 mAb (p=.027) is required for the synergistic effect. In-vivo administration of anti-CD20 mAb induces upregulation of CD137 on mouse NK cells (p=0.001), allowing subsequent targeting with anti-CD137 mAb. NK cell depletion completely abrogates the therapeutic effect of anti-CD20 plus anti-CD137 mAb combination (p<.001). In a xenotransplant disseminated lymphoma model (Figure 1A), rituximab plus anti-CD137 mAb provided superior reduction in tumor burden, as quantified by bioluminescence (p=.001; Figure 1B), and prolonged overall survival (p=.013; Figure 1C).

Conclusions:
Our results demonstrate the synergy of anti-CD137 mAb and rituximab by stimulation of rituximab-activated NK cells with anti-CD137 mAb to enhance ADCC. These results support a novel, sequential antibody approach against B cell malignancies by targeting first the tumor and then the host immune system.

Disclosures:
No relevant conflicts of interest to declare.
Chronic IFNγ Production Induces Anemia by Reducing Erythrocyte Lifespan and Inhibiting Erythropoiesis through An IRF-1/PU.1-Axis
Authors: Libregts Sten F. W. M. , Gutierrez Laura , de Bruin Alexander M. , Wensveen Felix M. , Papadopoulos Petros , van Ijcken Wilfred , Ozgur Zeliha , Philipsen Sjaak , Nolte Martijn A. 
Published: October 2019

Abstract
Abstract 4234
Anemia of chronic disease (ACD) is a complication accompanying many inflammatory diseases. The pro-inflammatory cytokine IFNγ has been implicated in this form of anemia, but the underlying mechanism remains unclear. Using a novel model for ACD, we demonstrate that IFNγ reduces both the lifespan and formation of red blood cells. Molecular analysis revealed that IFNγ induces expression of the transcription factors IRF-1 and PU.1 in both murine and human erythroid precursors. We found that IRF-1 binds to the promoter of PU.1 and induces its expression, leading to inhibition of erythropoiesis. Notably, downregulation of either IRF-1 or PU.1 expression is sufficient to overcome IFNγ-induced inhibition of erythropoiesis. PU.1 is a key transcription factor in hematopoietic lineage determination and its expression is sufficient to block erythroid differentiation and enhance myeloid differentiation. We therefore postulate that expression of IFNγ during infection can briefly shift the balance of erythroid towards myeloid differentiation, which will benefit the anti-microbial response. However, continuation of this feedback mechanism will hamper erythroid development and subsequently lead to anemia.
In conclusion, we here provide evidence for both a cellular and molecular mechanism by which IFNγ modulates erythropoiesis and how this contributes to the development of ACD.

Disclosures:
No relevant conflicts of interest to declare.
Role for BH3-Only Protein NOXA In Growth-Factor Deprivation and Early Erythropoiesis
Authors: Geest Christian R. , Wensveen Felix M. , Libregts Sten F.W.M. , de Bruin Alex M. , Derks Ingrid A.M. , Ekert Paul G. , Labi Verena , Villunger Andreas , Nolte Martijn A. , Eldering Eric 
Published: October 2019

Abstract
Abstract 4235
Red blood cell production is a strictly regulated process and homeostatic maintenance of the erythropoietic system requires equilibrium between the rate of erythroid cell production and red blood cell destruction. Hematopoietic cytokines play a crucial role in regulating expansion, differentiation and survival of erythrocyte progenitors. Shortage of growth factors triggers the mitochondrial apoptosis pathway, which is critically dependent on Bcl-2 family members. However, the contribution of this mechanism in the regulation of erythropoiesis remains ill-defined. This prompted us to screen for candidate genes involved in this process in erythroid progenitors. We found that the expression of Noxa, a pro-apoptotic Bcl-2 family member, is upregulated during erythroid differentiation and following cytokine-withdrawal in erythroid progenitor cells. Knockdown or deletion of Noxa in IL-3 dependent human and murine erythroid progenitor cell lines increased Mcl-1 levels, which correlated with markedly decreased apoptosis following cytokine withdrawal. Importantly, Noxa ablation in mice increased extra-medullary erythropoiesis, resulting in enhanced numbers of early splenic erythroblasts and circulating reticulocytes. Noxa-deficient hematopoietic progenitors were more resistant to apoptosis induced by growth factor deprivation and displayed increased colony-forming potential. In addition, combined loss of Noxa and Bim resulted in enhanced resistance of erythroid progenitors to cytokine withdrawal compared to WT or single Bim knockouts, suggesting a non-redundant role for Noxa and Bim in regulating survival of erythroid progenitors in response to cytokine deprivation. Finally, in a model of acute haemolytic anaemia, deletion of Noxa enhanced subsequent hematocrit recovery. Together, these findings identify a non-redundant role for BH3-only protein Noxa in the regulation of erythroblast survival during early erythropoiesis. Therefore, Noxa may be a novel component to control red blood cell numbers and modulation of this pathway could be envisaged in therapeutic options for treatment of anaemia.

Disclosures:
No relevant conflicts of interest to declare.