bluuebunny/crossref_metadata_2025_split huggingface dataset:
Induction of T Cell Immunity Using a Multipeptide Cocktail Containing XBP1, CD138 and CS1 Peptides in Smoldering Multiple Myeloma
Authors: Bae Jooeun , Prabhala Rao H. , Song Weihua , Tai Yu-Tzu , Anderson Kenneth C. , Munshi Nikhil C 
Published: October 2019

Abstract
Abstract 5039
Smoldering multiple myeloma (SMM) patients are at high risk for progression to active multiple myeloma (MM), making them candidates for novel immunotherapeutic strategies to prevent or delay disease progression. Among potential strategies, the ability to induce cytotoxic T lymphocytes (CTL) against multiple immunogenic epitopes provides a framework for overcoming major therapeutic challenges including heterogeneity of tumor associated antigen expression, frequent mutations of specific antigens, and variability of the human T-cell repertoire among individuals. In this study, we provide evidence that a cocktail of four immunogenic HLA-A2 specific peptides, heteroclitic XBP1 US184–192, heteroclitic XBP1 SP367–375, native CD138260–268 and native CS1239–247, induces specific CTL response in T cells from SMM patients. Following repeated rounds of multipeptide stimulation, we induced development of CD8+ CTL from SMM patients' T cells. The multipeptide specific-CTL demonstrated polyfunctional immune activities including high levels of IFN-g production, cell proliferation and cytotoxicity against MM cells in an HLA-A2 restricted manner. The multipeptide-specific CTL displayed increased memory (CD45RO+) and activated (CD69+) CD3+CD8+ T lymphocytes, suggesting that a multipeptide vaccine has the potential to induce durable memory by generating specific memory CTL with characteristics of effector T cells against MM cells. In addition, the multipeptide-specific CTL demonstrated peptide-specific responses to each of the relevant epitopes including heteroclitic XBP1 US184–192, heteroclitic XBP1 SP367–375, native CD138260–268 and native CS1239–247, but not against an irrelevant HLA-A2-specific MAGE-3271–279 peptide in various functional assays including antigen-triggered CD137 (4-1BB) expression, IFN-g production and CD107a up-regulation. Therefore, these results suggest the potential of inducing a broad spectrum of immune responses against selected XBP1 unspliced, XBP1 spliced, CD138 and CS1 target antigens in SMM using multipeptide vaccination. In conclusion, these studies provide the framework for clinical trials of vaccination in patients with SMM to delay or prevent progression to active MM.

Disclosures:
Bae: Oncopep Inc. : Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties. Anderson:Oncopep Inc. : Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties. Munshi:Oncopep Inc: Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties.
Anti-ABCG2 Monoclonal Antibody in Combination with Paclitaxel-Nanoparticles Against Cancer Stem-Like Cell Activity in Multiple Myeloma
Authors: Yang Cuiping , Dou Jun , Chen Baoan , Sun Yunyu , Wang Yonglu , Li Xueming , Zhu Han , Li Zhi 
Published: October 2019

Abstract
Abstract 5044
In spite of the past efforts and progress made in treatment multiple myeloma (MM), most MM patients have eventually relapsed and died of the cancer. Cancer stem cells (CSCs) are considered responsible for continued growth and recurrence of cancer. The purpose of this study was to investigate the effects of anti-ABCG2 monoclonal antibody (mAb) in combination with paclitaxel-Fe3O4 nanoparticles (PTX-NPs) on CD138−CD34−MM cancer stem-like cells (MM CSCs) isolated from MM cell line JJN3. In our results, the MM CSCs expressed higher levels of the ABCG2 transporter, exhibited high proliferative, clonogenic and migratory potency, and demonstrated strong drug resistance and tumorigenicity when compared to non-CD138−CD34−MM cells. Incubation of mAb with PTX-NPs remarkably induced G/M cell cycle arrest, and increased synergistic induction of MM CSC apoptosis compared with incubation with PTX-NPs or PTX or mAb alone. More importantly, mAb in combination with PTX-NPs led to a significant reduction in the tumor volume, to a visible alleviation of murine lytic bone lesions and to a markedly increased survival rate in contrast to using a single agent in MM CSCs when it was transplanted to nonobese diabetic/severe combined immunodeficiency mice. Our study is the first to report on the anti-MM CSC activities by PTX-NPs as single agent or used together with mAb to treat MM. This finding from our study provides a rationale for future clinical trials.

Disclosures:
No relevant conflicts of interest to declare.
Nitrite Inhibits Platelet Reactivity in Presence of Deoxygenated Red Blood Cells As Measured by Flow Cytometry
Authors: Akrawinthawong Krittapoom , Piknova Barbora , Sibmooh Nathawut , Fucharoen Suthat , Schechter Alan N. 
Published: October 2019

Abstract
Abstract 5146
Nitric oxide (NO), a small gas molecule with multiple functions in the body, has been shown to have several precursors in body, the most abundant of which is nitrite. In the last decade several studies show that nitrite is reduced to NO by various enzymatic and non-enzymatic reductive processes, especially at low oxygenation conditions. These pathways are alternative mammalian sources of NO as compared to its enzymatic production by a family of nitric oxide synthase enzymes (NOS). NO has long been known to be a potent inhibitor of platelet function but the physiological and pathological implications of this has not been well clarified. We recently showed that addition of nitrite into plasma in the presence of red blood cells inhibits platelet aggregation and that this effect, as measured by cGMP production is enhanced by deoxygenation of erythrocytes. In order to study these effects more thoroughly on the molecular level, we have been developing flow-cytometric assays to study molecular processes on the platelet cell membrane known to correlate with platelet aggregation. We focused on P-selectin (CD62P) and activated GpIIb/IIIa (PAC-1) levels in platelets exposed to three activators, ADP, collagen and thrombin, in the presence of various concentrations of red blood cells and at variable levels of oxygen. We found that nitrite at physiological concentration (0. 1 to 1. 0 uM) significantly inhibited exposure of both of these surface markers on the outer membrane of platelets at levels of hematocrit above 23% and mean oxygen levels lower than 49 mmHg. The effect increased with increasing hematocrit and decreasing oxygen saturation into the hypoxic range. Addition of an NO scavenger prevented nitrite-related platelet inhibition, but addition of an inhibitor of NOS or of xanthine oxidoreductase had no effect. These results indicate that physiological levels of nitrite ions in the blood can modulate platelet reactivity in the presence of partially deoxygenated erythrocytes by the reduction to NO and that this process can modulate platelet activation and aggregation levels and confirm and extend our previous report (Srihirun et al, PLoS One 7, e30380, 2012), done primarily using aggregation assays. Our flow cytometry assays not only allows a more detailed and systematic study of the kinetics and equilibrium aspects of the aggregation process, but also offers a possibility to identify the individual molecular processes involved in these effects. The results may also explain certain differences between arterial and venous thrombosis.

Disclosures:
Schechter: NIH: Employment, co-inventor of NIH patent on use of nitrite in disease, co-inventor of NIH patent on use of nitrite in disease Patents & Royalties.
SNX3 Regulates Recycling of the Transferrin Receptor and Iron Assimilation in Developing Erythrocytes*
Authors: Chen Caiyong , Santos Daniel Garcia , Ishikawa Yuichi , Seguin Alexandra , Li Liangtao , Fegan Katherine H. , Hildick-Smith Gordon J. , Cooney Jeffrey D. , Chen Wen , King Matthew J. , Schultz Iman J. , Yien Yvette Y. , Dalton Arthur J. , Kingsley Paul D , Palis James , Hattangadi Shilpa , Lodish Harvey F. , Ward Diane M. , Kaplan Jerry , Maeda Takahiro , Ponka Prem , Paw Barry H. 
Published: October 2019

Abstract
Abstract 607
Developing erythrocytes acquire large amounts of iron through the transferrin (Tf) cycle for heme synthesis. The Tf cycle involves unidirectional transport of transferrin-transferrin receptor 1 (Tf-TfR1) complexes from the plasma membrane to the early and recycling endosomes (Figure). Besides the requirement for the basic trafficking machinery, specific sorting molecules exist to ensure the efficient re-cycling of Tf-TfR1 complexes and targeted iron delivery. The trafficking of TfR1 from recycling endosomes to the cell surface was shown to be mediated by Sec15L1, an exocyst component, as its mutation causes anemia in the hemoglobin deficit (hbd) mouse. The sorting mechanisms responsible for earlier trafficking steps in intracellular transferrin cycle, however, are poorly understood.

Here we report that sorting nexin 3 (SNX3), a cargo-specific retromer component, facilitates the endocytic recycling of TfR1, and thus, is required for the proper delivery of iron to erythroid progenitors for heme synthesis (Figure). Snx3 is highly expressed in hematopoietic tissues of zebrafish and mouse. Morpholino-mediated knockdown of snx3 in zebrafish embryos leads to a profound anemia. shRNA silencing of Snx3 in mouse primary fetal liver cells and mouse Friend erythroleukemia (MEL) cells inhibits the production of hemoglobin. We demonstrate that these defects are due to impaired transferrin-mediated iron uptake and delivery to the mitochondria. The impaired iron assimilation can be complemented with non-transferrin bound iron chelates, such as Fe-SIH (salicylaldehyde isonicotinoyl hydrazone). Furthermore, we show that SNX3 may act through direct physical interaction with TfR1 to sort Tf-TfR1 complexes to the recycling endosomes.
Our data from genetic, biochemical, and chemical biological studies collectively show that SNX3 regulates TfR1 trafficking and iron homeostasis in developing erythrocytes. The identification of SNX3 as an essential co-regulatory protein that regulates Tf-mediated iron delivery for heme synthesis provides a new genetic tool for exploring human disorders of iron metabolism, such as the hypochromic anemias, and erythropoiesis.
* Cell Metabolism (in revision).

Disclosures:
No relevant conflicts of interest to declare.
The Impact of Novel Molecular Markers on Risk Stratification in Acute Myeloid Leukemia
Authors: Löwenberg Bob , Valk Peter , Touw Ivo P. , Delwel Ruud 
Published: October 2019

Abstract
Abstract SCI-33
The treatment of acute myeloid leukemia (AML) remains associated with considerable failure rates. From a therapy viewpoint AML presents as a kaleidoscope of highly diverse diseases for which the (epi)genetic heterogeneity of the disease is the overriding determinant of treatment failure. Diverse coemerging molecular abnormalities (gene mutations, expression abnormalities) related, for instance, to the genes CEBPA, nucleophosmin-1, FLT-3, RUNX1, ASXL1, P53, G-CSF-R, IDH1/IDH2, DNMT3A, and EVI-1 in variable composite configurations, determine the considerable “interindividual” and “intraindividual” variations of AML. As these somatic genetic abnormalities in transformed hematopoietic progenitor cells perturb critical cellular pathways and functions, they confer a profound impact upon the clinical phenotype of the disease—and also may define unique diagnostic subtypes (diagnosis) and therapeutic resistance (treatment response). Using genome-wide approaches and well-defined cohorts, the identified molecular biomarkers provide insights into the variability of treatment outcome, and furnish an informative framework for risk-adapted treatment decisions according to disease risk and therapeutic responsiveness (prognosis and treatment choice). In this presentation, examples of strategies to assess the prognostic impact of genomic abnormalities will be discussed, as well as the challenge to integrate the numerous markers into meaningful decision algorithms that can be used for more individualized therapy choices, for example, regarding the use of particular therapeutic agents and the utility (risk-benefit) of allogeneic stem cell transplantation.

Disclosures:
Löwenberg: Skyline Diagnostics: Membership on an entity's Board of Directors or advisory committees.
Gut Microbiota and Intestinal Inflammation
Authors: Garrett Wendy S. 
Published: October 2019

Abstract
Abstract SCI-49
Numerous studies of the microbiota that are found throughout the human body are under way, with the goal of unraveling the role of microbes in human physiology. Using experimental colitis models, we are investigating microbes that may instigate chronic inflammation, and we are studying putative beneficial microbes whose reduced presence may impact not only host response to the microbiota but also the behavior of the endogenous microbiota. Genomic approaches, combined with following microbial community response to a spectrum of dietary and pharmacologic perturbations, are shedding light on the dynamic operations of the microbiota that influence health and disease. Chronic inflammation in the intestine is not only the central pathophysiologic mechanism of inflammatory bowel disease (IBD) but also a key contributor to colorectal cancer. Ongoing work on the colorectal microbiome, using experimental models and human tumors, will be discussed. Collectively, our studies support the utility of wedding culture-independent and culture-dependent studies with mouse models for defining how the gut microbiota works in concert with the mucosal immune system to shape disease susceptibility for IBD and colorectal cancer.

Disclosures:
Garrett: Groupe Danone: Research Funding.
Dual SYK/JAK Inhibition Has a Broader Anti-Tumor Activity In Both ABC and GCB Types Of Diffuse Large B Cell Lymphoma
Authors: Ma Jiao , Coffey Greg , Lu Pin , Cheng Shuhua , Guo Ailin , Pandey Anjali , Wang Y. Lynn 
Published: October 2019

Abstract
With increasing understanding of the genetic basis of diffuse large B cell lymphoma (DLBCL), more targeted therapies have been developed. However, most of these therapies have activities only against a subset of DLBCL, activated B-cell like subtype (ABC), in particular, where the BCR pathway is known to be chronically active. Specific single-molecule directed therapies, although effective, often induce resistance over long term treatment. Agents with broader activities are needed for the treatment of this heterogeneous disease. Since both the BCR and JAK/STAT pathways are strongly implicated in the pathogenesis of DLBCL, in the present study, we evaluated the anti-lymphoma activity of PRT062070 (PRT2070), a novel compound that dually targets both JAK and SYK signaling pathways. We analyzed a panel of DLBCL cells lines, of both ABC and germinal center B-cell like (GCB) subtypes, as well as DLBCL patient samples, for cellular and molecular events affected by PRT2070.
Immunoblotting analyses showed that ABC and GCB subtype of DLBCL cells exhibit different JAK/STAT and BCR signaling profiles. For instance, AKT was highly expressed in GCB cells, whereas STAT3 was more strongly expressed in ABC cells. In GCB cell lines, PRT2070 blocked G1/S transition and caused cell cycle arrest. In contrast, in ABC cells, the drug induced apoptosis and down-regulated MCL1 protein. Furthermore, array of PRT2070-treated ABC subtype of DLBCL cells revealed that several STAT3 regulated cytokines and chemokines, including IL10, were down-regulated, confirming that PRT2070 affects ABC-DLBCL cells via JAK/STAT pathway. Genetic knockdown of both JAK and SYK reduced the growth and the survival of DLBCL cells more pronouncedly than knockdown of JAK or SYK alone, suggesting the anti-tumor activity of PRT2070 was mediated by dual inhibition of JAK and SYK signaling pathways. Importantly, JAK/STAT and BCR signaling can be blocked by PRT2070 in GCB and non-GCB primary human DLBCL cells, which led to death of these cells. Our work provided mechanistic insights into the actions of JAK/SYK dual inhibitor PRT2070 suggesting that the drug may be a potent treatment of DLBCL with a broader anti-tumor activity in both ABC and GCB subtypes of the lymphoma.

Disclosures:
Coffey: Portola Pharmaceuticals: Employment. Pandey:Portola Pharmaceuticals: Employment.
Mir-15a/16-1 Haploinsufficiency Contributes To Myeloma Progression
Authors: Chesi Marta , Garbitt Victoria , Palmer Stephen , Bergsagel P. Leif 
Published: October 2019

Abstract

Deletions of chromosome 13 occur in about 50% of multiple myeloma (MM) patients, with monosomy being the most common (85%), and small interstitial deletions, often involving the Rb gene, representing only 15% of cases. In contrast to CLL, where a minimal deleted region (MDR) has been mapped to the DLEU2/miR-15a/16-1 locus, no MDR has been identified in MM. The prognostic significance of monosomy 13 has been overshadowed by its strong association with high-risk MM, mostly t(4;14) and t(14;16) translocations. Genomic analysis of 28 MM tumors from Vk*MYC mice identified recurrent (27%) monosomy of the syntenic chromosome 14, with focal bi-allelic deletions of Rb1 in three independent tumors. One tumor presented a focal monoallelic interstitial deletion of the mirR15a-16.1 cluster. Reasoning that the biological significance of monosomy 13 would be conserved between human and murine MM, we carried out genetic crosses between Vk*MYC and mice heterozygous for Rb1 (MYC/Rb1), for the DLEU2/miR-15a/16-1 locus (MYC/MDR) or for the miR-15a/16-1 cluster only (MYC/MIR).
All of the MYC/Rb1 mice died around one year of age of pituitary tumors without a significant plasma cell expansion compared to the Vk*MYC mice alone. In contrast, both the MYC/MDR+/- and MYC/MIR+/- mice exhibited a progressive monoclonal plasmacytosis affecting secondary lymphoid organs, with associated shorter overall survival. The development of extra-medullary MM was further accelerated in MYC/MDR -/- and MYC/MIR -/- mice, and was reminiscent of that observed in Vk*MYC crossed with Emu-BCL2 mice. As previously shown for the CLL-like disease that develops in the MIR and MDR mice, the MM phenotype is more pronounced in the MYC/MDR than the MYC/MIR, and in the homozygous than the heterozygous mice. Although BCL2 has been proposed as a target of the miR-15a/16-1, it has not been identified among genes whose expression is altered in MIR null B lymphocytes, where instead miR-15a/16-1 deletion promotes proliferation. In contrast, we found significant BCL2 upregulation in some MM tumors from MYC/MIR and MYC/MDR, suggesting that miR-15a/16-1 deletion in MM provides a survival signal that renders plasma cells less dependent on the BM microenvironment. We propose that selection for monosomy 13 in MM is driven in at least in part by loss of one copy of the miR cluster.

Disclosures:
No relevant conflicts of interest to declare.
Improving Hematopoietic Stem Cell Based Gene Therapy By Targeting CD133+ Cells
Authors: Goebel Benjamin , Brendel Christian , Abriss Daniela , Kneissl Sabrina , Brugman Martijn , Buchholz Christian J. , Serve Hubert , Grez Manuel 
Published: October 2019

Abstract

Introduction
Generally, CD34+ cells are used for genetic modification in gene therapy trials. CD34+ cells consist of a heterogeneous cell population with mostly limited long-term repopulating capabilities, resulting in low long-term engraftment levels in particular in those diseases in which gene modified cells lack a proliferative advantage over non-modified cells. Therefore, modifications in gene transfer vectors and gene transfer strategies are required to improve long-term clinical benefit in gene therapy patients. One particular attractive approach to solve this problem is the improvement of HSC based gene transfer by specifically targeting cells with long-term engraftment capabilities.

Material and Methods
We constructed lentiviral gene transfer vectors (LV) specifically targeting CD133+ cells, a cell population with recognized long-term repopulating capabilities. Targeting is achieved by pseudotyping with engineered measles virus (MV) envelope proteins. The MV glycoprotein hemagglutinin, responsible for receptor recognition, is blinded for its native receptors and displays a single-chain antibody specific for CD133 (CD133-LV). These vectors were compared to VSV-pseudotyped lentiviral vectors in in vitro and in vivocompetitive repopulation assays using mobilized peripheral blood CD34+ cells.

Results
Superior transduction of isolated human hematopoietic stem cell populations (CD34+CD38- or CD34+CD133+ cells) compared to progenitor cell populations (CD34+CD38+ or CD34+CD133-) could be shown using the newly developed CD133-LV. Transduction of total CD34+ cells with CD133-LV vectors resulted in stable gene expression and gene marked cells expanded in vitro, while the number of VSV-G-LV transduced CD34+ cells declined over time. Competitive repopulation experiments in NSG mice showed a significantly improved engraftment of CD133-LV transduced HSCs. At ∼12 weeks post-transplantation gene marked hematopoiesis was dominated by the progeny of CD133-LV transduced cells in 42 out of 52 transplanted animals in the bone marrow and 39 out of 45 transplanted animals in the spleen, respectively. Consistent with this data we could show that stem cell content in the CD133-LV transduced population is about five times higher compared to the VSV-transduced population using a limiting dilution competitive repopulation assay (LDA-CRU). Experiments showing proof of principle for the application of this technology for the correction of Chronic Granulomatous Disease (XCGD) using patient derived CD34+ cells are currently ongoing.

Discussion
In conclusions this new strategy may be promising to achieve improved long-term engraftment in patients treated by gene therapy.

Disclosures:
No relevant conflicts of interest to declare.