Glycovariant CD37 Small Modular Immuno-Pharmaceutical (TruADhanCe™ SMIP) Promotes Enhanced Natural Killer Cell Mediated Cytotoxicity against Primary Chronic Lymphocytic Leukemia Cells.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 1744-1744
Author(s):  
Sarwish Rafiq ◽  
Carolyn Cheney ◽  
Peter A Thompson ◽  
Tony Siadak ◽  
Paul Algate ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Natural Killer ◽  
B Cell Lymphoma ◽  
Leukemia Cells ◽  
New Variant ◽  
Direct Cytotoxicity ◽  
Cross Linker

Abstract Abstract 1744 Poster Board I-770 CD37 is a tetraspanin transmembrane family protein that is strongly expressed on the surface of mature human B-cells and transformed mature B-cell lymphoma and leukemia cells, including CLL cells. It is expressed minimally or is absent on normal T-cells, natural killer cells, monocytes, and granulocytes. Predominant expression of CD37 on CLL cells makes it an ideal candidate to target with potential agents for treatment of CLL. TRU-016, a Small Modular ImmunoPharmaceutical protein (SMIP) targeted towards the extracellular region of CD37, is presently in clinical trials in CLL patients. TRU-016 consists of variable regions (scFv) and engineered constant regions encoding the human IgG1 domains. We have previously reported that SMIP-016, the chimeric precursor of the fully humanized TRU-016, induced apoptosis in CLL B cells in the presence of goat anti-human Fc ab cross-linker through a novel, caspase-independent pathway. Furthermore, SMIP-016 showed potent in-vivo activity in a SCID xenograft mouse model. Aside from direct cytotoxicity, SMIP-016 mediates antibody-dependent cellular cytotoxicity (ADCC) by NK cells both in vitro and in vivo. Recently, in an attempt to enhance the ADCC function, a new variant of SMIP-016, Tru-ADhanCe SMIP-016, has been created with a modification of the glycosylation of the Fc portion of the molecule. TRU-ADhanCe SMIP-016 has been shown to exhibit enhanced binding to both low- and high-affinity molecular variants of human CD16 (FcRIII) and augmented ADCC potency when compared to SMIP-016. In this study, we compared TruADhanCe SMIP-016 and SMIP-016 in direct cytotoxicity and ADCC experiments using CLL B-cells. While SMIP-016, and TruADhanCe SMIP-016 mediated comparable direct cytotoxicity at 24, 48 and 72 hrs in the presence of anti-human Fc crosslinker, the TruADhanCe SMIP-016 resulted in 2 to 4 fold increased NK cell mediated ADCC function. Consistent with the comparable direct cytotoxic effects, the early phosphorylation patterns were similar in cells treated with TruADhanCe SMIP-016 or SMIP-016 in the presence of anti-human Fc cross linker. Ongoing studies are aimed to define the mechanistic basis of the enhanced ADCC function by TruADhanCe SMIP-016 and to determine if use of soluble CD16.Fc as a cross-linker, an in vitro model of in vivo Fc receptor binding, may reveal enhanced apoptotic-signaling of TruADhanCe SMIP-016. These results suggest potential use of TruADhanCe versions of TRU-016 with enhanced ADCC function as an alternate for TRU-016 in B cell malignancies including CLL therapy. [This work was supported by D. Warren Brown Foundation, Leukemia and Lymphoma Society and National Cancer Institute.] Disclosures Thompson: Trubion Pharmaceuticals: Employment. Siadak:Trubion Pharmaceuticals: Employment. Algate:Trubion Pharmaceuticals: Employment. Cerveny:Trubion Pharmaceuticals: Employment.

GlycoVariant Anti-CD37 Small Modular Immuno-Pharmaceutical Exhibits Superior Natural Killer Cell Mediated Cytotoxicity Against Chronic Lymphocytic Leukemia Cells at Low Concentrations and Low Antigen Density

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 1847-1847
Author(s):  
Sarwish Rafiq ◽  
Carolyn M Cheney ◽  
Gerard Lozanski ◽  
Rosa Lapalombella ◽  
Xiaokui Mo ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Nk Cells ◽  
Nk Cell ◽  
B Cell Lymphoma ◽  
Leukemia Cells ◽  
Low Concentrations ◽  
New Variant ◽  
Direct Cytotoxicity

Abstract Abstract 1847 CD37 is a tetraspanin transmembrane family protein that is strongly expressed on the surface of mature human B cells and transformed mature B cell lymphoma and leukemia cells, including CLL cells. It is absent or minimally expressed on normal T cells, NK cells, monocytes, and granulocytes. Predominant expression of CD37 on CLL cells makes it an ideal candidate to target with potential agents for treatment of CLL. TRU-016, a small modular immunopharmaceutical protein (SMIP) that specifically binds to an extracellular region of CD37, is presently in clinical trials in CLL patients. TRU-016 includes humanized immunoglobulin variable regions (scFv) fused to a human IgG1 Fc region. We have previously reported that SMIP-016, the chimeric version of the humanized TRU-016, induced apoptosis in CLL B cells in the presence of goat anti-human Fc antibody cross-linker through a novel, caspase-independent pathway. Furthermore, SMIP-016 showed potent in vivo activity in a SCID xenograft mouse model. Aside from direct cytotoxicity, SMIP-016 mediates antibody-dependent cellular cytotoxicity (ADCC) by NK cells both in vitro and in vivo. In an attempt to enhance its ADCC function, a new variant of SMIP-016, SMIP-016GV, was designed with a modification of the glycosylation of the Fc portion of the molecule. SMIP-016GV exhibits enhanced binding to both low- and high-affinity molecular variants of human CD16 (FcγRIII) and augments ADCC potency when compared to SMIP-016. In this study, we compared SMIP-016GV and SMIP-016 in direct cytotoxicity and ADCC against CLL B cells. While SMIP-016 and SMIP-016GV mediated comparable direct cytotoxicity at 48 hrs in the presence of goat anti-human Fc crosslinker, the SMIP-016GV resulted in 2 to 4 fold increase in NK cell mediated ADCC function at all effector to target ratios tested. This increased ADCC with SMIP-016GV was observed using NK cell effectors derived from both normal as well as CLL-affected individuals. In addition, this enhanced cytotoxicity was sustained at concentrations of SMIP-016GV as low at 5E-6 μg/ml. These low concentrations of SMIP-016GV were also able to mediate superior ADCC in 697 cells expressing as few as 10,000 molecules of surface CD37 antigen. Furthermore, NK cells stimulated with the glycovariant were potently activated and released 3 to 4 fold more IFNγ compared to SMIP-016. Ongoing studies are aimed at defining other effector cells which may interact with SMIP-016GV via different Fcγ Receptors. Collectively, these results suggest potential use of the SMIP-016GV with enhanced ADCC function as an alternate for TRU-016 in B cell malignancies including CLL therapy. Disclosures: Siadak: Trubion Pharmaceuticals: Employment.

Pathologic Co-Expression and Physical Interaction of c-MYC and BCL6 in B-Cell Lymphomas.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 2-2 ◽  
Author(s):  
Masumichi Saito ◽  
Ryan T. Phan ◽  
Herbert C. Morse ◽  
Laura Pasqualucci ◽  
Riccardo Dalla-Favera
Keyword(s):  
B Cells ◽  
B Cell ◽  
Cell Lymphoma ◽  
Somatic Hypermutation ◽  
B Cell Lymphoma ◽  
Transgenic Animals ◽  
Primary Lymphoma ◽  
Physical Interaction

Abstract Deregulated expression of the proto-oncogenes BCL6 and c-MYC caused by chromosomal translocation or somatic hypermutation is common in non-Hodgkin B cell lymphoma derived from germinal center (GC) B cells, including diffuse large cell lymphoma (DLBCL) and Burkitt lymphoma (BL). Normal GC B cells express BCL6, whereas, surprisingly, they do not express c-MYC, suggesting that the expression of this oncogene in BL and DLBCL (20% of cases) is ectopic (Klein, U. et al. Proc Natl Acad Sci U S A100, 2639–2644, 2003). Here we report that c-MYC is absent in proliferating GC B cells because it is transcriptionally suppressed by BCL6, as demonstrated by the presence of specific BCL6 binding sites in the c-MYC promoter region and by chromatin immunoprecipitation experiments showing that BCL6 is bound to these sites in vivo. Thus, c-MYC escapes BCL6-mediated suppression in lymphoma leading to the co-expression of the two transcription factors, an event never observed in immunohistochemical and gene expression profile analysis of normal GC B cells. Surprisingly, co-immunoprecipitation experiments and in vitro binding experiments indicate that, when co-expressed, BCL6 and c-MYC are physically bound in a novel complex detectable in DLBCL and BL cell lines as well as in primary lymphoma cases. The formation of the BCL6/c-MYC complex has several significant functional consequences on the function of both c-MYC and BCL6: 1) a two fold, BCL6-binding dependent increase in c-MYC half-life, an event that has been shown to contribute to its oncogenic activation; 2) a synergistic increase in the ability of both BCL6 and c-MYC to suppress MIZ1-activated transcription of the p21CIP cell cycle arrest gene; 3) MYC-dependent inhibition of BCL6 acetylation by p300, an event that physiologically inactivates BCL6 via c-MYC-mediated recruitment of HDAC. Notably, the pathologic co-expression of c-MYC and BCL6 was shown to have pathologic consequences in vivo, since double transgenic BCL6/c-MYC mice display accelerated lymphoma development and the appearance of a novel GC-derived tumor phenotype not recognizable in single transgenic animals and containing the pathologic c-MYC/BCL6 complex. Thus, the pathologic co-expression and illegitimate physical interaction of BCL6 and c-MYC leads to an increase in the constitutive activity of both oncogenes. These results identify a novel mechanism of oncogenic function for BCL6 and c-MYC and a novel tumor-specific protein complex of potential therapeutic interest.

Assessing CD137 (4-1BB) As a Therapeutic Target in B-Cell Neoplasms,

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3735-3735
Author(s):  
Adam D Cohen ◽  
Indira D Joshi ◽  
Valentin Robu ◽  
Hossein Borghaei ◽  
Tahseen I. Al-Saleem ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
B Cells ◽  
Tumor Cell ◽  
B Cell ◽  
Marginal Zone ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Tumor Cell Proliferation

Abstract Abstract 3735 Agonist monoclonal antibodies (mAbs) to CD137, a co-stimulatory TNF receptor family member expressed on activated T and NK cells, can induce immune-mediated rejection of multiple murine tumor types, and a fully human anti-CD137 mAb, BMS-663513, is in early-phase clinical trials in solid tumors. Significant activity has been seen in murine lymphoma models, both alone and in combination with anti-CD20 mAbs, providing rationale for clinical studies in lymphoma patients. Recently, however, CD137 up-regulation on activated human B cells has been reported, with CD137 ligation causing enhanced B cell proliferation and survival. This raises the concern that mAb binding to CD137, if present, on B cell neoplasms may promote tumor cell proliferation and/or resistance to apoptosis that may counteract the beneficial effects on T and NK cells. We therefore sought to assess the expression of CD137 on a series of human cell lines and primary tumor samples from patients with B-cell neoplasms, and if expressed, to explore the consequences of ligation with the anti-CD137 agonist BMS-66513. First, archived paraffin-embedded lymph node specimens from patients with low-grade B-cell lymphoma (n=11: 5 follicular, 4 marginal zone, 2 small lymphocytic) and diffuse large B-cell lymphoma (n=15) were stained for CD137 by immunohistochemistry. Reactive tonsillar tissue served as a positive control. No CD137 expression was observed within any tumor cells. Next, fresh samples from 14 additional patients with known tumor involvement of peripheral blood or bone marrow (8 chronic lymphocytic leukemia, 1 mantle cell lymphoma, 3 myeloma, 2 marginal zone lymphoma) were analyzed by multi-color flow cytometry. Again, no CD137 expression was observed on the gated neoplastic cells. Baseline surface expression of CD137 was similarly absent in all B cell-derived lines tested (Raji, FCTxFL2, FSCCL, DoHH2, Jeko-1, RPMI8226). However, activation with PMA/Ionomycin could reproducibly induce CD137 expression (% positive: 0.17% → 91%) after 24 hours in 1 of the lines: the follicular lymphoma FSCCL. Interestingly, this was the only line tested that lacked constitutive expression of CD137 ligand (CD137L), suggesting some reciprocal regulation of ligand and receptor expression. Despite this up-regulation of CD137, in vitro ligation of PMA/Ionomycin-activated FSCCL cells with BMS-66513 did not further increase tumor cell proliferation, nor protect the cells from activation-induced cell death, in contrast to effects of CD137 ligation reported in normal B cells (Zhang et al, J Immunol 2010; 184:787). Similarly, BMS-663513 treatment of activated, CD137+ FSCCL cells did not diminish the apoptosis induced by doxorubicin or bortezomib treatment. In addition, FSCCL cells recovered from ascites 7 and 14 days following intraperitoneal injection in SCID mice did not express CD137, implying that CD137 up-regulation is not occurring in vivo during tumor growth. Finally, treatment of FSCCL cells with rituximab, either in vitro or in vivo, did not induce CD137 expression. In conclusion, we demonstrate a lack of steady-state CD137 expression on malignant B cells, confirming the prior study by Houot et al (Blood 2009; 114:3431) and extending these findings to include CLL/SLL for the first time. While CD137 could be induced in a single cell line upon non-specific activation, CD137 expression on FSCCL cells was not seen under physiologic conditions likely to be encountered in the clinical setting, consistent with the primary patient data. Furthermore, even when CD137 was expressed, ligation with the agonist anti-CD137 mAb BMS-663513 did not provide a pro-proliferative or anti-apoptotic signal. These studies provide reassurance and further rationale for exploring agonist anti-CD137 antibodies as therapies for B cell neoplasms. Disclosures: Borghaei: Lilly, Genentech, Amgen, Pfizer: Honoraria, Research Funding. Jure-Kunkel:Bristol Meyers Squibb: Employment.

B-1239, a Novel Anti-BAFF-R Afucosylated Human Antibody, Promotes Potent Natural Killer Cell- Mediated Antibody Dependent Cellular Cytotoxicity In Chronic Lymphocytic Leukemia Cells In- Vitro and Depletion Of Circulating Leukemic CLL B Cells In-Vivo

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 4185-4185 ◽  
Author(s):  
Emily M. McWilliams ◽  
Carolyn Cheney ◽  
Jeffrey A. Jones ◽  
Joseph M. M. Flynn ◽  
Kami Maddocks ◽  
...  
Keyword(s):  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
Cytotoxic Activity ◽  
Natural Killer ◽  
Lymphocytic Leukemia ◽  
Cellular Cytotoxicity ◽  
Antibody Dependent Cellular Cytotoxicity

Abstract B-cell activating factor (BAFF) belongs to the TNF ligand superfamily of cytokines involved in B cell survival and maturation. BAFF is produced by diverse cell types including innate immune cells like monocytes and dendritic cells as well as T cells, activated B cells, and bone marrow stromal cells. BAFF binds to the BAFF receptor (BAFF-R) with high affinity compared to the other BAFF receptors, BCMA and TACI. While BAFF is known to regulate normal B-cell development and proliferation, it also contributes to survival in chronic lymphocytic leukemia (CLL). We observed expression of BAFF-R on virtually all B cells from CLL patients. B-CLL cells have strong up-regulation of BAFF and BAFF-R compared to normal healthy B cells. We describe here the in-vitro and in-vivo evaluation in CLL of B-1239, a fully human anti-BAFF-R monoclonal IgG1 antibody. B-1239 is devoid of fucose residues in its Fc domain, resulting in enhanced binding to FCgammaRIIIa activating receptor on Natural Killer (NK) cells. While B-1239 failed to induce direct or complement mediated cytotoxicity, binding of B-1239 to CLL cells resulted in enhanced antibody dependent cellular cytotoxicity (ADCC) with allogeneic or autologous NK effector cells in-vitro. Indeed, at a therapeutically relevant concentration of 10 ug/mL B-1239 shows more than 30% increased relative cytotoxic activity over current CLL antibody therapeutic Rituximab. Dilutions of B-1239 down to 0.01 ug/mL showed similar cytotoxicity to the 10 ug/mL concentration. At 0.0001 ug/mL B-1239 has a 40% cytotoxic effect on CLL cells in ADCC assays while antibody therapeutic controls, like Rituximab, show virtually no cytotoxic activity. Furthermore, B-1239 mediated antibody-dependent cellular phagocytosis (ADCP) by monocyte-derived macrophages and mediated activation of monocytes and macrophages as detected by TNF-alpha production. Consistent with the cross reactivity to murine BAFF-R, flow cytometric analysis revealed binding of B-1239 to CD5+CD19+ leukemic B cells from Eu-Tcl-1 transgenic mouse CLL cells. A single dose of B-1239 by i.v injection into Eu-Tcl-1 mice resulted in dramatic reduction in circulating CD5+CD19+ leukemic B cells in all three B-1239 injected mice. In contrast, we observed continued increase of leukemic CD5+CD19+ populations in the two vehicle treated mice. Ongoing studies are focused on determining how targeting BAFF-R on CLL B-cells depletes the leukemic population both in-vitro and in-vivo and the downstream effects of targeting through this receptor. Collectively, these results demonstrate that targeting BAFF-R on CLL cells provides a B-cell specific approach for rapid and robust depletion of leukemic CLL cells and provides evidence for a strong therapeutic advantage in BAFF-R targeted therapies in CLL. Disclosures: Huet: Novartis: Employment, Employment Related Perks Other. Gram:Novartis: Employment, Employment Related Perks Other. Baeck:Novartis: Employment, Employment Related Perks Other.

scholarly journals Epstein-Barr Virus Type 2 Infects T Cells and Induces B Cell Lymphomagenesis in Humanized Mice

2018 ◽  
Vol 92 (21) ◽  
Author(s):  
Carrie B. Coleman ◽  
Julie Lang ◽  
Lydia A. Sweet ◽  
Nicholas A. Smith ◽  
Brian M. Freed ◽  
...  
Keyword(s):  
T Cells ◽  
B Cells ◽  
B Cell ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Humanized Mice ◽  
Cells In Culture

ABSTRACTEpstein-Barr virus (EBV) has been classified into two strains, EBV type 1 (EBV-1) and EBV type 2 (EBV-2) based on genetic variances and differences in transforming capacity. EBV-1 readily transforms B cells in culture while EBV-2 is poorly transforming. The differing abilities to immortalize B cellsin vitrosuggest thatin vivothese viruses likely use alternative approaches to establish latency. Indeed, we recently reported that EBV-2 has a unique cell tropism for T cells, infecting T cells in culture and in healthy Kenyan infants, strongly suggesting that EBV-2 infection of T cells is a natural part of the EBV-2 life cycle. However, limitations of human studies hamper further investigation into how EBV-2 utilizes T cells. Therefore, BALB/c Rag2nullIL2rγnullSIRPα humanized mice were utilized to develop an EBV-2in vivomodel. Infection of humanized mice with EBV-2 led to infection of both T and B cells, unlike infection with EBV-1, in which only B cells were infected. Gene expression analysis demonstrated that EBV-2 established a latency III infection with evidence of ongoing viral reactivation in both B and T cells. Importantly, EBV-2-infected mice developed tumors resembling diffuse large B cell lymphoma (DLBCL). These lymphomas had morphological features comparable to those of EBV-1-induced DLBCLs, developed at similar rates with equivalent frequencies, and expressed a latency III gene profile. Thus, despite the impaired ability of EBV-2 to immortalize B cellsin vitro, EBV-2 efficiently induces lymphomagenesis in humanized mice. Further research utilizing this model will enhance our understanding of EBV-2 biology, the consequence of EBV infection of T cells, and the capacity of EBV-2 to drive lymphomagenesis.IMPORTANCEEBV is a well-established B cell-tropic virus. However, we have recently shown that the EBV type 2 (EBV-2) strain also infects primary T cells in culture and in healthy Kenyan children. This finding suggests that EBV-2, unlike the well-studied EBV-1 strain, utilizes the T cell compartment to persist. As EBV is human specific, studies to understand the role of T cells in EBV-2 persistence require anin vivomodel. Thus, we developed an EBV-2 humanized mouse model, utilizing immunodeficient mice engrafted with human cord blood CD34+stem cells. Characterization of the EBV-2-infected humanized mice established that both T cells and B cells are infected by EBV-2 and that the majority of infected mice develop a B cell lymphoma resembling diffuse large B cell lymphoma. This newin vivomodel can be utilized for studies to enhance our understanding of how EBV-2 infection of T cells contributes to persistence and lymphomagenesis.

A CD47xCD19 Bispecific Antibody That Remodels the Tumor Microenvironment for Improved Killing and Provokes a Memory Immune Response to Cancer B Cells

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 44-44
Author(s):  
Walter G. Ferlin ◽  
Xavier Chauchet ◽  
Vanessa Buatois ◽  
Susana Salgado-Pires ◽  
Limin Shang ◽  
...  
Keyword(s):  
B Cells ◽  
Tumor Microenvironment ◽  
Tumor Growth ◽  
B Cell ◽  
Cell Lymphoma ◽  
Treatment Strategies ◽  
B Cell Lymphoma ◽  
Tumor Killing

Abstract Up-regulation of CD47 in hematological and solid cancers correlates with poor clinical prognosis. CD47 interaction with SIRPα provides a ‘don't eat me’ signal that allows healthy cells to limit elimination by immune cells, in particular macrophages. Although tumor-associated macrophages (TAMs) are often considered pro-tumorigenic, several studies report a high phagocytic potential and tumoricidal function in the presence of therapeutic antibodies (Ab). Therefore, targeting the CD47-SIRPα pathway in the tumor microenvironment is an attractive approach to maximize the tumor killing potential of TAMs to boost tumor destruction. However, clinical development of monoclonal Abs to CD47 is likely to be hindered by the ubiquitous expression of CD47 leading to rapid drug elimination and toxicity including anemia. To address these concerns, we have created NI-1701, a bispecific Ab that drives efficacious binding only to CD19+B cells by pairing a high affinity anti-CD19 targeting arm to an anti-CD47 arm of optimized affinity.. In addition to in vitro data demonstrating that the bispecific Ab, NI-1701, effectively kills CD19+ human tumor B cells through ADCP (antibody-dependent cellular phagocytosis) and antibody-dependent cell-mediated cytotoxicity (ADCC), we have observed significant tumor killing in vivo, as either a monotherapy or in a combination approach. NI-1701 controlled sub-cutaneously implanted Raji cell tumor growth in NOD/SCID mice in a manner dependent on the co-ligation of both CD19 and CD47. Examination of the excised tumors revealed that NI-1701 reshaped the tumor microenvironment by enhancing the tumoricidal activity of macrophages (i.e., more macrophages engulfing tumor cells), by promoting an antitumor M1-like phenotype, and reducing the proportion of CD11b+Gr1+myeloid-derived suppressor cells (MDSCs). Extending these findings to a disseminated in vivo model, NI-1701 eliminated tumor cells from the peripheral blood, bone marrow and liver in mice transplanted either with the B-Acute Lymphocytic Leukemia (B-ALL) cell line NALM-6 or with primary cells from B-ALL patients. Furthermore, NI-1701 also abrogated tumor growth more efficiently than the BTK inhibitor ibrutinib in a Diffuse Large B-Cell Lymphoma (DLBCL) patient-derived xenograft (PDX) mouse model. As combination therapies are gaining traction as successful treatment strategies in the clinic, we next tested the effect of blocking CD47 biology in combination with clinically validated molecules. Interestingly, in NOD/SCID mice implanted with Raji cells, NI-1701 was shown to be more efficacious at controlling tumor cell growth than Rituximab. A combination of NI-1701 and Rituximab was shown to act synergistically at controlling tumor growth and leading to tumor regression in some mice. Finally, in a syngeneic re-challenge model, using bispecific reagents targeting CD47 blockade to the A20 murine B-cell lymphoma, we observed the induction of a durable and protective anti-tumor response when combined with a single administration of cyclophosphamide. Importantly, in vitro safety studies demonstrate a favorable binding profile of NI-1701 to B cells compared with erythrocytes, no evidence of platelet activation or aggregation and no haemagglutination at and above anticipated therapeutic concentrations. Single and multiple dose studies in non-human primates demonstrated favorable elimination kinetics and no effects on hematological parameters (e.g., red blood cell and platelet counts) up to 100mg/kg, the highest dose tested. Taken together, we describe a novel bispecific approach that balances a safe yet effective blockade of CD47 with a high selectivity for a B cell associated antigen resulting in impressive tumor cell killing in a range of preclinical models. The effects on both the reshaping of the tumor microenvironment and the induction of long term tumor immunity provide further evidence that manipulation of myeloid lineage cells (e.g., macrophages and dendritic cells) is a promising approach for the next frontier in immune-oncology treatment strategies. NI-1701 is in preclinical enabling studies in preparation for a Phase I clinical study in patients with CD19+ B cell malignancies, planned for early 2017. Disclosures Ferlin: Novimmune S.A.: Employment, Equity Ownership. Chauchet:Novimmune S.A.: Employment. Buatois:Novimmune S.A.: Employment. Salgado-Pires:Novimmune S.A.: Employment. Shang:Novimmune S.A.: Employment. Dheilly:Novimmune S.A.: Employment. Masternak:Novimmune S.A.: Employment. Johnson:Novimmune S.A.: Employment. DiPersio:Incyte Corporation: Research Funding. Kosco-Vilbois:Novimmune S.A.: Employment. Fischer:Novimmune S.A.: Employment.

scholarly journals Addiction of B Cell Lymphomas to microRNA-17-92 Is Mediated By a Single Target Gene

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 1258-1258
Author(s):  
Katia Schoeler ◽  
Teresa Mittermeier ◽  
Andreas Villunger ◽  
Klaus Rajewsky ◽  
Verena Labi
Keyword(s):  
B Cells ◽  
B Cell ◽  
Mammalian Cells ◽  
Conflicts Of Interest ◽  
B Cell Lymphoma ◽  
Messenger Rnas ◽  
B Cell Lymphomas ◽  
Apoptosis Pathway

Mature microRNAs (miRNA) are short non-coding RNAs that regulate gene expression by binding to messenger RNAs (mRNA) in a sequence-specific manner, causing translational repression and/or mRNA decay. The mammalian genome harbors thousands of miRNA genes, many of which are organized into transcriptionally co-regulated clusters such as miR-17-92. Knockout of the miR-17-92 cluster gene in mice blocked B lymphopoiesis, and ectopic miR-17-92 expression sufficed to initiate B cell lymphomas and autoimmunity. In humans, the miR-17-92 gene is commonly amplified or overexpressed via MYC-driven transcription in diffuse large B cell and Burkitt's lymphomas. A computationally predicted shared target of the miR-17-92 miRNAs is the pro-apoptotic BCL-2 family protein BIM, central to life-death decisions in mammalian cells. To clarify the contribution of miR-17-92:Bim interactions to the miR-17-92 knockout and overexpression phenotypes, we engineered a unique in vivo system of conditional mutagenesis of the nine Bim 3'UTR miR-17-92 binding sites. Instead of causing the predicted B cell developmental block, interruption of miR-17-92:Bim interactions produced a selective inability of B cells to resist cellular stress; and prevented lymphocyte hyperplasia caused by Bim haploinsufficiency. Surprisingly, partial genetic disruption of miR-17-92:Bim interactions was sufficient to fully prevent B cell lymphoma formation in two out of three mice using two independent pre-clinical MYC-driven cancer models. This protective effect could be attributed to an increased activity of the mitochondrial apoptosis pathway in pre-malignant B cells, as apoptosis was abolished by concomitant overexpression of an anti-apoptotic BCL-2 protein. MYC-driven B lymphoma cells are addicted to miR-17-92 function. Our data build on these results and strongly suggest that miR-17-92:Bim interactions are vital in this context as acute ablation of miR-17-92:Bim interactions effectively promoted lymphoma cell apoptosis, both in vitro and in vivo. In conclusion, among hundreds of putative miR-17-92 target mRNAs a single direct binding partner is vital for lymphoma development and maintenance, a discovery whose therapeutic exploitation is of major relevance. Disclosures No relevant conflicts of interest to declare.

scholarly journals Validation of epigenetic mechanisms regulating gene expression in canine B-cell lymphoma: An in vitro and in vivo approach

PLoS ONE ◽  
2018 ◽  
Vol 13 (12) ◽  
pp. e0208709 ◽  
Author(s):  
Silvia Da Ros ◽  
Luca Aresu ◽  
Serena Ferraresso ◽  
Eleonora Zorzan ◽  
Eugenio Gaudio ◽  
...  
Keyword(s):  
Gene Expression ◽  
B Cell ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Epigenetic Mechanisms
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