ANTISENSE GENE THERAPY DIRECTED AGAINST EBNA-1 IN EBVASSOCIATED B CELL LYMPHOMAS RESULTS IN POTENTIATION OF CHEMOTHERAPY IN VITRO AND DECREASED TUMOR VIRULENCE IN SCID MICE

1997 ◽  
Vol 14 (4) ◽  
pp. A53
Author(s):  
Myra B. Morgan ◽  
Pablo Cagnoni ◽  
Jill Lacy ◽  
Tyler J. Curiel
Keyword(s):  
Gene Therapy ◽  
B Cell ◽  
Scid Mice ◽  
B Cell Lymphomas ◽  
Antisense Gene

scholarly journals Treating B Cell Lymphomas with Anti CD81 Antibodies

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 4180-4180
Author(s):  
Felipe Vences-Catalan ◽  
Chiung-Chi Kuo ◽  
Ranjani Rajapaksa ◽  
Caroline Duault ◽  
Ronald Levy ◽  
...  
Keyword(s):  
Tumor Growth ◽  
B Cell ◽  
Scid Mice ◽  
Comparable Efficacy ◽  
B Cell Lymphomas ◽  
In Vivo Bioluminescence Imaging ◽  
Human Igg1 ◽  
Mouse Igg2a

Abstract The tetraspanin CD81 associates with CD19 on B cells; this molecular complex functions as co-receptor to lower the threshold of BCR-initiated B cell activation. Recently we have shown the importance of CD81 in tumor growth and metastasis of solid tumors (Vences-Catalan et al., 2015). However, the role of CD81 in lymphoid malignancies has not been explored. Previous studies demonstrated anti-proliferative effects of anti-CD81 antibodies on human B cell lymphomas using in vitro assays (Oren et al., 1990). Here we tested the therapeutic effect of an anti-human CD81 antibody in vivo against Raji and SUP-B8 B cell lymphomas using a xenograft model in SCID mice. Our studies demonstrated that our anti-human CD81 antibody (mouse IgG1) had therapeutic effect comparable to Rituximab (human IgG1) (Figure 1A). Yet, the two antibodies differ in their ability to mediate antibody-dependent cell cytotoxicity (ADCC), Rituximab is known to be highly effective, whereas the mouse IgG1 anti-CD81 antibody is not expected to mediate ADCC. To enhance the anti-CD81-mediated ADCC, we class switched the hybridoma to mouse IgG2a; we also engineered a chimeric antibody containing human IgG1ADCC-HIGH Fc constant region. Indeed, mouse IgG2a and the chimeric human IgG1 anti-CD81 mAb showed a remarkable increase in NK cell-mediated ADCC as well as complement-dependent cytotoxicity (CDC) when compared to Rituximab in vitro (data not shown) and in vivo (Figure 1B). These results suggest that CD81 can be a potential therapeutic target on B cell lymphomas by virtue of both its direct cytotoxic effect and as a mediator of ADCC and CDC. The humanized IgG1 version is being developed as a therapeutic candidate. Comparable efficacy of anti-CD81 to Rituximab. SCID mice were I.V.-injected with 1.5x106 Raji-GFP-Luc cells, tumors growth proceeded for 5 days before IP injection of 4 weekly doses of 100 ug of the indicated antibodies. (A) Survival of Raji-GFP-Luc bearing SCID mice given anti CD81 (n=30), Rituximab (n=20) or control MsIgG1 (n=30). (B) In vivo bioluminescence imaging of tumor growth in mice injected (left to right) with control mouse IgG1; anti-CD81 (MsIgG1); anti-CD81 MsIgG2a; chimeric anti-CD81 (HuIgG1) and Rituximab. Comparable efficacy of anti-CD81 to Rituximab. SCID mice were I.V.-injected with 1.5x106 Raji-GFP-Luc cells, tumors growth proceeded for 5 days before IP injection of 4 weekly doses of 100 ug of the indicated antibodies. (A) Survival of Raji-GFP-Luc bearing SCID mice given anti CD81 (n=30), Rituximab (n=20) or control MsIgG1 (n=30). / (B) In vivo bioluminescence imaging of tumor growth in mice injected (left to right) with control mouse IgG1; anti-CD81 (MsIgG1); anti-CD81 MsIgG2a; chimeric anti-CD81 (HuIgG1) and Rituximab. Disclosures Levy: Kite Pharma: Consultancy; Five Prime Therapeutics: Consultancy; Innate Pharma: Consultancy; Beigene: Consultancy; Corvus: Consultancy; Dynavax: Research Funding; Pharmacyclics: Research Funding.

Malignant hematopoietic cell lines: In vitro models for the study of primary mediastinal B-cell lymphomas

2015 ◽  
Vol 39 (1) ◽  
pp. 18-29 ◽  
Author(s):  
Hans G. Drexler ◽  
Stefan Ehrentraut ◽  
Stefan Nagel ◽  
Sonja Eberth ◽  
Roderick A.F. MacLeod
Keyword(s):  
B Cell ◽  
Cell Lines ◽  
In Vitro Models ◽  
Hematopoietic Cell ◽  
B Cell Lymphomas ◽  
Hematopoietic Cell Lines

scholarly journals Targeting N-myristoylation for therapy of B-cell lymphomas

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Erwan Beauchamp ◽  
Megan C. Yap ◽  
Aishwarya Iyer ◽  
Maneka A. Perinpanayagam ◽  
Jay M. Gamma ◽  
...  
Keyword(s):  
B Cell ◽  
Cancer Cell ◽  
Cancer Cell Line ◽  
Cell Receptor ◽  
B Cell Lymphomas ◽  
Cancer Cell Death ◽  
Anti Cancer ◽  
Xenograft Models ◽  
Patients Experience

Abstract Myristoylation, the N-terminal modification of proteins with the fatty acid myristate, is critical for membrane targeting and cell signaling. Because cancer cells often have increased N-myristoyltransferase (NMT) expression, NMTs were proposed as anti-cancer targets. To systematically investigate this, we performed robotic cancer cell line screens and discovered a marked sensitivity of hematological cancer cell lines, including B-cell lymphomas, to the potent pan-NMT inhibitor PCLX-001. PCLX-001 treatment impacts the global myristoylation of lymphoma cell proteins and inhibits early B-cell receptor (BCR) signaling events critical for survival. In addition to abrogating myristoylation of Src family kinases, PCLX-001 also promotes their degradation and, unexpectedly, that of numerous non-myristoylated BCR effectors including c-Myc, NFκB and P-ERK, leading to cancer cell death in vitro and in xenograft models. Because some treated lymphoma patients experience relapse and die, targeting B-cell lymphomas with a NMT inhibitor potentially provides an additional much needed treatment option for lymphoma.

scholarly journals Anti-CD19 inhibits the growth of human B-cell tumor lines in vitro and of Daudi cells in SCID mice by inducing cell cycle arrest

Blood ◽  
1994 ◽  
Vol 83 (5) ◽  
pp. 1329-1336 ◽  
Author(s):  
MA Ghetie ◽  
LJ Picker ◽  
JA Richardson ◽  
K Tucker ◽  
JW Uhr ◽  
...  
Keyword(s):  
Cell Cycle ◽  
B Cell ◽  
Cell Cycle Arrest ◽  
Inhibitory Effect ◽  
Scid Mice ◽  
Cell Tumor ◽  
Cycle Arrest ◽  
A Chain

Abstract In this report, we extend our previous findings that IgG or F(ab′)2 fragments of HD37 anti-CD19 antibody (Ab) in combination with the immunotoxin (IT), RFB4-anti-CD22-deglycosylated ricin A chain (dgA) (but neither reagent alone), prolonged the survival of SCID mice with disseminated human Daudi lymphoma (SCID/Daudi mice) to 1 year at which time they still remained tumor-free. We explored the mechanisms by which the HD37 Ab exerts antitumor activity in vivo by studying its activity in vitro. We found that it has antiproliferative activity (IC50 = 5.2 - 9.8 x 10(-7) mol/L) on three CD19+ Burkitt's lymphoma cell lines (Daudi, Raji, and Namalwa) but not on a weakly CD19-positive (CD19lo) pre-B cell tumor (Nalm-6). The inhibitory effect was manifested by cell cycle arrest, but not apoptosis. Results using three additional anti-CD19 Abs, suggest that the affinity of the antibody and possibly the epitope which it recognizes may effect its capacity to transmit a signal that induces cell cycle arrest. Hence, therapeutically useful Abs may exert anti-tumor activity by a variety of mechanisms, each of which should be evaluated before undertaking clinical trials in humans.

An Activating Mutation (Ser525Pro) within the Transactivation Domain of REL in Two Patients with Human B-Cell Lymphomas Enhances REL’s In Vitro Transforming Activity.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 2617-2617
Author(s):  
Heiko Trautmann ◽  
Daniel T. Starczynowski ◽  
Christiane Pott ◽  
Lana Harder ◽  
Norbert Arnold ◽  
...  
Keyword(s):  
B Cell ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Transactivation Domain ◽  
Wild Type ◽  
Spleen Cells ◽  
B Cell Lymphomas ◽  
Chicken Spleen ◽  
Human B Cell

Abstract REL/NF-κB transcription factors are implicated in the control of apoptosis and cell growth particular in hematopoetic lineages. The REL locus at chromosomal region 2p13–16 is frequently amplified in B-cell lymphomas including diffuse-large B-cell lymphoma (DLBCL) and may play a role in lymphomagenesis. Overexpression of wild-type REL can transform chicken lymphoid cells in culture, and several experimentally-generated mutations within the REL C-terminal transactivation domain (TAD) have been previously shown to enhance REL’s transforming ability. We analysed 83 B-cell lymphomas included in the ‘Deutsche Krebshilfe’ funded network „Molecular Mechanisms in Malignant Lymphoma“ for the presence of activating mutations in the coding region of REL. We performed a systematic dHPLC screening for mutation discovery and identified an identical point mutation in two human B-cell lymphomas (a t(14;18)-positive follicular lymphoma and a mediastinal B-cell lymphoma) that changes Ser525 to Pro within the REL TAD. In the mediastinal B-cell lymphoma, the mutation in REL was proven to be of germline origin. FISH showed an amplification of the REL locus in the tumor cells of this case. Quantitative allelic discrimination of S525P indicates that the mutant REL gene was over-represented in both cases. By in vitro experiments we could show that the S525P mutation enhances the in vitro transforming ability of REL in chicken spleen cells. In addition, REL-S525P differs from wild-type REL in its ability to activate certain κB site-containing reporter plasmids in transient transfection assays. In particular, REL-S525P has a reduced ability to activate the human manganese superoxide dismutase (MnSOD) promoter in A293 cells; however, the MnSOD protein is over-expressed in REL-S525P-transformed chicken spleen cells as compared to wild-type REL-transformed cells. Ser525 of REL falls within a sequence that is similar to other known phosphorylation sites of the IκB kinase, and REL-S525P shows a reduced ability to be phosphorylated by IKKα in vitro. The S525P mutation reduces IKKα- and TNFα-stimulated transactivation by REL, as measured in GAL4 reporter assays. Furthermore, REL-S525P-transformed chicken spleen cells are more resistant to TNFα-induced cell death than cells transformed by wild-type REL. These results represent the first identification of a tumor-derived activating mutation in the REL proto-oncogene, and they suggest that the S525P mutation contributes to the development of human B-cell lymphomas by altering REL’s ability to induce target gene expression by affecting an IKKα-regulated transactivation activity.

BCL6, p53 and Molecular Targeted Therapy in B-Cell Lymphomas.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 1484-1484 ◽  
Author(s):  
Leandro C.A. Cerchietti ◽  
Jose M. Polo ◽  
Gustavo F. Da Silva ◽  
Steve M. Dowdy ◽  
Catoretti M. Giorgio ◽  
...  
Keyword(s):  
Targeted Therapy ◽  
B Cell ◽  
Target Gene ◽  
Target Genes ◽  
Wild Type ◽  
B Cell Lymphomas ◽  
Lymphoma Cells ◽  
Sequential Administration ◽  
Wild Type P53

Abstract The BCL6 transcriptional repressor is an oncogene often constitutively expressed in diffuse large B-cell lymphomas (DLBCL). The oncogenic mechanism of action of BCL6 presumably involves repression of its direct target genes. We recently developed a targeted therapy agent (called BPI - BCL6 peptide inhibitor) that specifically blocks transcriptional repression by BCL6, and which causes apoptosis in lymphoma cells in vitro and in vivo. We present here potent and stable derivatives of BPI able to specifically eradicate lymphoma cells after a single dose in vitro. Expression array studies of BCL6 target genes reactivated by BPI revealed that one such gene is the p53 tumor suppressor. p53 was also recently shown to be BCL6 target gene by Phan et. al., Nature 2004. We find that BCL6 represses p53 in DLBCL cells through recruitment of the SMRT and N-CoR corepressors, which explains how BPI, which blocks recruitment of these corepressors, reactivates p53. We next wished to determine the contribution of BCL6-mediated repression of p53 to lymphomagenesis, and how p53 modulation might affect BCL6 targeted therapy strategies for DLBCL. We found that BPI could induce p53 target gene expression in DLBCL cells with wild-type p53 and that small molecules or peptides that block p53 rescue apoptosis induced by BPI. In contrast, although BPI also induces p53 in DLCBL cells with mutant p53, there was no activation of p53 target genes and no rescue by p53 blocking molecules. However BPI causes apoptosis of DLBCL cells regardless of p53 status indicating the BCL6 mediates its oncogenic actions through both p53 dependent and independent pathways. p53 is usually wild-type in DLBCL and our analysis of >100 patients show that p53 protein is, surprisingly, still expressed in these tumors. These data suggest that p53 is not fully active in DLBCL cells, consistent with the fact that we found that BCL6 also directly represses upstream activators of p53 such as Chk1 and ATR. BCL6 blockade thus can fully restore activity of p53, both by increasing its expression levels and by enhancing its activation by upstream mediators. Accordingly, sequential administration of p53 activating molecules that enhance p53 activity, potently synergizes with BPI in killing lymphoma cells. BPI also synergizes with chemotherapy drugs that act in part through p53, such as doxorubicin. From these studies we conclude that i) BCL6 mediates lymphomagenesis by direct repression of p53 and upstream target gene pathways; ii) BCL6 positive lymphomas are dependent on BCL6 for their survival regardless of whether p53 is wild type or mutated; iii) Sequential targeting of BCL6 and p53 with BPI and a p53 activating molecule or doxorubicin is likely to be a highly effective therapeutic regimen for patients with DLBCL, especially for the majority who have wild-type p53; iv) The new BPI derivatives are sufficiently potent and stable to be tested in the clinical setting.

Superior Immunogenicity of Idiotype Fab Fragments As Compared to Entire Immunoglobulin for Active Lymphoma Immunotherapy

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 1633-1633
Author(s):  
Marcelo A. Navarrete ◽  
Benjamin Kisser ◽  
Hendrik J. Veelken
Keyword(s):  
Flow Cytometry ◽  
T Cells ◽  
T Cell ◽  
B Cell ◽  
B Cell Lymphomas ◽  
Cd8 Cells ◽  
Fab Fragments ◽  
The Individual

Abstract Abstract 1633 Introduction: The individual collection of epitopes within the variable regions of the unique immunoglobulin expressed by every mature B-cell lymphoma (idiotype, or Id) represents a tumor-specific antigen and lends itself as a target for therapeutic vaccination strategies. Immunization with tumor Id has the capacity to elicit polyclonal antibody responses as well as CD8+ and CD4+ T cells recognizing Id-derived peptides presented on class I and class II HLA molecules, respectively. Due to a perceived low immunogenicity of lymphoma-derived Id, most Id vaccines tested in clinical trials so far have been formulated as conjugates with the strongly immunogenic carrier keyhole limpet hemocyanin (KLH). In contrast, we have consistently observed high rates of humoral and cellular anti-Id immune responses in consecutive trials of active immunization with unconjugated recombinant Fab fragments of Id in indolent B-cell lymphomas (Bertinetti et al., Cancer Res. 2006; Navarrete et al., BLOOD 2011). We therefore hypothesized that Id Fab fragment might be intrinsically more immunogenic than entire Id Ig and tested this hypothesis by comparative in vitro experiments. Methods: Monocyte-derived dendritic cells (DC) where loaded with human monoclonal IgG, papain-digested Fab fragments, Fc fragments, or recombinant lymphoma-derived Fab fragments. Functional DC phenotypes were assessed by flow cytometry of crucial maturation and activation markers. IL-10 and IL-12 was measured in DC culture supernatants by ELISA. Antigen-loaded DC where subsequently used for priming of CFSE-labeled autologous peripheral blood mononuclear cells. Stimulated T cell populations were analyzed by multicolor flow cytometry. Results: Loading of DC with Fab, Fc, IgG, or mixtures of Fab and Fc fragments did not alter surface expression of CD11c, CD80, CD83, CD86, HLA-DR, PDL-1 and PDL-2 on DC. Likewise, the various antigens did not influence the cytokine release by DC during the loading or maturation process. DC loaded with isolated Fab fragments induced significantly higher proliferation of both CD4+ and CD8+ T cells than undigested IgG. The mean proliferation rate of CD4+ cells stimulated with Fab fragments was 18.5% versus 5.6% for undigested IgG stimulation (p=0.021); proliferation rates of CD8+ cells were 14.2% versus 6.2% (p=0.034). These results were reproduced for 4 different monoclonal IgGs tested on 4 different donors. The addition of Fc fragments to Fab reduced the proliferation rates of CD4+ and CD8+ cells to 10.2% and 8.6% respectively. In addition, DC loaded with undigested IgG induced a relative increase in the number of CD25high/FoxP3+ regulatory T cells compared with Fab stimulation (8.2% versus 1.4%; p<0.01). Conclusions: Isolated Fab fragments, i.e. the Id portions that contain the individual candidate antigenic epitopes of B-cell lymphomas, prime autologous T cells in vitro more efficiently than entire IgG. This finding is consistent with the high immune response rate against recombinant unconjugated Fab fragments observed in vivo in our clinical vaccination trials. Peptide sequences shared between Ig molecules that are predominantly located in the IgG Fc fragment appear to exert an inhibitory effect on T-cell priming. In accordance with our recent in vivo data in a syngeneic mouse model of Id vaccination (Warncke et al., Cancer Immunol. Immunother. 2011), this effect may be mediated by effective activation of Treg. Fab fragments therefore appear to be the more immunogenic and therefore preferable Ig antigenic format for active anti-Id immunotherapy. Furthermore, the inhibitory effects of IgG Fc offers a potential explanation for the recently reported lack of efficacy of Id vaccination in IgG-expressing follicular lymphomas in a randomized phase III trial, in which patients with IgM-expressing lymphomas, in contrast, had a significant benefit from Id vaccination in intention-to-treat analyses (Schuster et al., JCO 2011). Disclosures: No relevant conflicts of interest to declare.

scholarly journals TC-PTP is required for the maintenance of MYC-driven B-cell lymphomas

Blood ◽  
2009 ◽  
Vol 114 (24) ◽  
pp. 5016-5023 ◽  
Author(s):  
Ryan M. Young ◽  
Avital Polsky ◽  
Yosef Refaeli
Keyword(s):  
B Cells ◽  
B Cell ◽  
Protein Tyrosine Phosphatases ◽  
Molecular Target ◽  
Cell Tumor ◽  
Tumor Proliferation ◽  
B Cell Lymphomas ◽  
Tumor Maintenance

Abstract We sought to determine the contributions of protein tyrosine phosphatases (PTPs) to the pathogenesis of B-cell lymphomas. We found that T-cell PTP (TC-PTP) was overexpressed in transformed B cells. We hypothesized that TC-PTP may be a tumor-promoting gene that is regulated by MYC overexpression in B cells. Knockdown of TC-PTP in murine tumors resulted in decreased cell viability in vitro because of an arrest in the G1 phase of the cell cycle. Furthermore, cells with reduced TC-PTP expression were unable to either engraft or expand in vivo. Taken together, these data indicate that TC-PTP is required for B-cell tumor maintenance. Our data also suggested a correlation between TC-PTP expression and MYC overexpression. To investigate this further, we used malignant murine B cells that contain a doxycycline-repressible MYC transgene. We found that repression of MYC overexpression with doxycycline reduced TC-PTP expression. Moreover, enforced expression of TC-PTP showed partial rescue of the expansion of tumor cells after suppression of MYC overexpression. These results suggest that MYC overexpression induces TC-PTP overexpression, which in turn promotes tumor proliferation, implicating TC-PTP as an important effector of the MYC-driven proliferation program in B-cell lymphomas. Thus, TC-PTP may be a suitable molecular target for the treatment of B-cell lymphomas.

Sign in / Sign up

Export Citation Format

Share Document