CD40L Modulates TRAIL-Induced Apoptosis in Germinal Center Derived B Cell Lymphomas.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 4630-4630
Author(s):  
Marion Travert ◽  
Patricia Ame-Thomas ◽  
Thierry Fest ◽  
Céline Pangault ◽  
Gilbert Semana ◽  
...  
Keyword(s):  
Follicular Lymphoma ◽  
B Cell ◽  
Cell Lines ◽  
Germinal Center ◽  
B Cell Lymphoma ◽  
B Cell Lymphomas ◽  
Lymphoma Cells ◽  
Over Expression ◽  
Induced Apoptosis ◽  
Transformed Cell Lines

Abstract Follicular lymphoma are characterized by the rearrangement of the bcl-2 gene, present in more than 90% of patients. Over-expression of the bcl-2 protein resulting from this translocation is associated with the inability to eradicate the lymphoma, by inhibiting apoptosis. Despite the median survival ranges from 8 to 15 years, leading to the designation of indolent lymphoma, patients with advanced-stage follicular lymphoma are not cured with current therapeutic options. Numerous reports have shown that Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) can induce apoptosis in a wide variety of transformed cell lines of diverse lineage, but does not appear to kill normal cells, even though TRAIL mRNA is expressed at significant levels in most normal tissues. As cell death induced by TRAIL occurs almost exclusively in tumor cells, it suggests that this drug is safe to use as an antitumor therapy. We therefore investigated the efficiency of this cytokine to induce apoptosis in germinal center derived B cell lymphoma, despite bcl-2 over-expression. Our study was also designed to evaluate the role of CD40L, one of the main differentiation signal involved in B cell maturation during the germinal center reaction, on the regulation of TRAIL-induced apoptosis. This study was performed on three germinal center derived tumor cell lines (BL2, VAL and RL), and on normal and tumor primary cells obtained from human tonsils and lymph nodes. Our data show that normal B lymphocytes obtained from tonsil biopsies are resistant to TRAIL-mediated apoptosis, when B lymphoma cells issued from lymph node of numerous patients are significantly sensitive to the cytokine. When we treat these lymphoma cells with trimeric huCD40L, we partly rescue these cells from spontaneous apoptosis which naturally occurs after few days of culture, and reverse by 50% TRAIL-mediated apoptosis when cells were co-treated with huCD40L for 16 hours. Similar results were reproduced on some germinal center derived cell lines. BL2 was indeed found highly sensitive to TRAIL-induced apoptosis following a 24 hour exposure. On the opposite, VAL and RL were almost insensitive. We have demonstrate that apoptosis is exclusively mediated by TRAIL-R1 in BL2. Analysis of signalling pathways revealed that the protection to TRAIL-induced apoptosis by CD40L is due to some specific anti-apoptotic molecules that will be described. Genes encoding these molecules are targets of the NFκB signalling pathway activated by CD40L. Our results suggest that activation of NFκB and induction of anti-apoptotic molecules by CD40L play an important role in the protection of germinal center derived B cell lymphomas against apoptosis. Then, NFκB inhibitors may be wise to use in clinical trials in conjunction with TRAIL against follicular lymphomas.

scholarly journals Prediction and Optimization of the Therapeutic Effect of mTOR Inhibitors in Aggressive B-Cell Lymphomas

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 4441-4441
Author(s):  
Chengfeng Bi ◽  
Xiaoyan Zhang ◽  
Zhang Xuan ◽  
Wing C Chan ◽  
Timothy McKeithan ◽  
...  
Keyword(s):  
B Cell ◽  
Conflicts Of Interest ◽  
Cell Lymphoma ◽  
Mtor Inhibitors ◽  
B Cell Lymphoma ◽  
Mechanism Study ◽  
B Cell Lymphomas ◽  
Lymphoma Cells ◽  
Induced Apoptosis ◽  
Aggressive B Cell Lymphoma

Abstract Mechanistic target of rapamycin complex 1 (mTORC1) is a central integrator of nutrient and growth factor inputs that controls cell growth in all eukaryotes. Rapamycin and its analogs (rapalogs) have been approved for the treatment of relapsed mantle cell lymphoma. A large proportion of aggressive B-cell lymphoma patients, however, respond poorly to rapalogs. The second generation of mTOR inhibitors function as ATP-competitive inhibitors (TORi), directly targeting the mTOR catalytic site. TORis have been proven to be more effective than rapalogs in cancer treatment. However, the mechanism underlying the cytotoxic effect of TORis in aggressive B-cell lymphomas remains unclear. In this study, we demonstrated that TORi-induced apoptosis is predominantly dependent on loss of mTORC1-mediated 4EBP phosphorylation. Knocking out Rictor, a key component of mTORC2, or inhibiting p70S6K has little effect on TORi-induced apoptosis. In contrast, increasing the EIF4E:4EBP ratio by either overexpressing EIF4E or knocking out 4EBP1/2 protected lymphoma cells from TORi-induced cytotoxicity. Furthermore, down-regulation of MCL1 and BCL-XL expression plays an important role in TORi-induced apoptosis whereas BCL-2, in cells with high expression, confers resistance to TORi treatment. Based on the mechanism study, we demonstrated that BH3 profiling, primarily NOXA and HRK stimulation, can effectively predict the cytotoxicity of the TORi in lymphoma cells. Also, in combination with pro-apoptotic drugs, especially BCL-2 inhibitors, the TORi exerted powerful anti-tumor effects both in vitro and in vivo. Taken together, this study provides mechanistic insight in TORi treatment in aggressive B-cell lymphoma and identified a mean to predict and improve its effectiveness clinically. Disclosures No relevant conflicts of interest to declare.

B Cell Lymphomas Are Resistant towards Bone Morphogenetic Protein (BMP) Induced Growth Inhibition.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 2381-2381
Author(s):  
Kanutte Huse ◽  
Marianne B. Eide ◽  
Christian Kersten ◽  
Erlend B. Smeland ◽  
June H. Myklebust
Keyword(s):  
Growth Inhibition ◽  
B Cell ◽  
Cell Lines ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Lymphoma Cell ◽  
Lymphoma Cells ◽  
Bmp Receptors ◽  
Induced Apoptosis

Abstract Bone morphogenetic proteins (BMPs) belong to the TGF-β superfamily, and mediate their effects mainly through the Smad signalling pathway. Whereas TGF-β is well established as one of the most potent negative regulators in hematopoietic cells, the role of BMPs remains more elusive. We have previously shown that BMP-6 inhibits the growth of naïve and memory human B cells. As high BMP-6 mRNA expression is associated with poor outcome in diffuse large B cell lymphoma (DLBCL; Rosenwald et al, N Engl J Med 2002), we hypothesized that resistance towards BMP-induced growth inhibition is a possible mechanism for lymphomagenesis. In the current study, 7 B cell lymphoma cell lines (representing Burkitt lymphoma (BL) and DLBCL) and tumour material from lymphoma patients were investigated to unravel the role of BMPs in lymphomas. We analyzed the expression of BMP receptors by FACS analysis, and found variable expression of the BMP receptor type I (Alk2, Alk3 and Alk6) and type II (BMP RII, Activin RIIA and RIIB) among the cell lines and in primary lymphoma cells, suggesting variable binding of BMPs. We next investigated the effect of BMP-2, BMP-4, BMP-6 and BMP-7 on proliferation and survival of B lymphoma cell lines, and found 2 of 7 cell lines to be resistant towards BMP-2 and BMP-4 induced growth inhibition. In contrast, 4 of 7 and 7 of 7 cell lines were resistant to BMP-6 and BMP-7 induced growth inhibition, respectively. In Sudhl6 cells that were highly sensitive to BMP-2 and BMP-6 induced apoptosis and inhibition of proliferation, we demonstrated that the cytokines IL-10, CD40 Ligand and BLyS were able to counteract the negative effects induced by BMPs, while IL-2 and IL-4 were not. On the contrary, both BMP-2 and BMP-6 greatly increased anti-IgM activation induced apoptosis. In resistant lymphoma cells, the BMPs were not able to induce detectable levels or induced low levels of phosphorylated SMAD1/5/8 compared to sensitive cell lines. Low or no increase in phosphorylation of SMAD1/5/8 induced by BMPs could only partly be explained by low/ undetectable expression of BMP receptors. Hence, upregulation of inhibitory Smads (Smad6, Smad7) or mutations in receptors or Smads represent other possible mechanisms for resistance to BMPs in lymphomas, and this is currently under investigation. We also investigated if the lymphoma cells produced BMPs themselves and found that 5 of 7 cell lines and 3 of 5 primary lymphomas produced significant amounts of BMP-7. Some lymphoma cells also had detectable levels of BMP-4 and BMP-6. Our findings that lymphoma cells are resistant towards BMP-7 and to some degree BMP-6 induced growth inhibition, whereas they produce these cytokines, suggest that resistance towards BMP induced signalling in B cell lymphomas can contribute to increased tumour growth.

scholarly journals Prosurvival and Chemoprotective Effects of Tumor-Associated Macrophages Reversed By Anti-CSF-1R Monoclonal Antibody in B-Cell Lymphomas

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 498-498
Author(s):  
Anupama Gopisetty ◽  
Myriam Foglietta ◽  
Min Zhang ◽  
Zhiqiang Wang ◽  
Nathan Fowler ◽  
...  
Keyword(s):  
B Cell ◽  
Cell Line ◽  
Tumor Cells ◽  
Cell Lines ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Lymphoma Cell ◽  
B Cell Lymphomas ◽  
Lymphoma Cells ◽  
Tumor Survival

Abstract The results of gene expression profiling (GEP) and immunohistochemical studies indicate that survival is worsened by macrophages (MΦ) in the tumor microenvironment of various B-cell lymphomas including follicular lymphoma (FL) and diffuse large B-cell lymphoma (DLBCL). Tumor-associated macrophages (TAMs) are known to be different from other types of MΦ, but the effects of TAMs that worsen prognosis in B-cell lymphoma are essentially unknown, as are the mechanisms of these effects. Here, we determined the phenotype and effects of TAMs on tumor survival, proliferation, and drug resistance in B-cell lymphomas and evaluated strategies to reverse their effects. As compared to peripheral blood monocytes (Mo) from normal donors (ND), Mo from FL patients were differentiated less into M1 MΦ (defined as CD68+CD163loCD206loCD86hi) by culture with CSF-1 for 5 days followed by IFN-g + LPS for 2 days more. In contrast, Mo from FL patients and ND were differentiated similarly into M2 MΦ (defined as CD68+CD163hiCD206hiCD86lo) by culture with CSF-1 followed by IL-4. Consistent with this, MΦ gene signatures from FL tumors were more similar to previously-described signatures of M2 rather than M1 MΦ (Martinez et al, J Immunol, 2006, 177(10):7303-11). In co-culture, primary FL tumor cells and lymphoma cell lines (including RL, a transformed FL cell line; Granta 519, a mantle cell lymphoma (MCL) cell line; and Raji, a Burkitt lymphoma cell line) induced differentiation of Mo into MΦ. Differentiation could be prevented by CS4 monoclonal antibody (mAb), a fully human IgG1 anti-human CSF-1R mAb (ImClone/Eli Lilly), but not isotype control Ab. Elevated levels of CSF-1 in culture supernatants after addition of CS4 mAb and real-time PCR of tumor cells suggested secretion of CSF-1 by lymphoma cells. Spontaneous apoptosis of primary FL and MCL tumor cells, determined by Annexin V and propidium iodide staining, was significantly reduced by co-culture with ND Mo (p<0.01), whether pre-differentiated into MΦ with CSF-1 or not, but this protection could be reversed by CS4 mAb. Mo and/or pre-differentiated MΦ protected primary FL and MCL tumor cells from cytotoxic effects of doxorubicin and/or bendamustine (p<0.01), but CS4 mAb reversed this effect. To assess effects of MΦ on proliferation, lymphoma cell lines (RL, Granta 519, and Raji) were CFSE-labeled prior to co-culture with Mo and doxorubicin, and proliferation assessed by CFSE dilution by flow cytometry in the presence or absence of CS4 or isotype control mAbs. MΦ promoted proliferation of all three cell lines, but this effect could be reversed by CS4 mAb. To further understand the mechanism by which MΦ promote tumor survival and growth, we performed phosflow analysis and found increased phosphorylation of STAT3 in co-cultured lymphoma cells. Consistent with this, we observed a correlation between an 11-gene STAT3 activation signature, described by Huang et al in DLBCL tumors (J Clin Oncol, 2013, 52.8414), and a MΦ gene signature in whole genome GEP studies of 191 FL tumors (Pearson correlation co-efficient=0.396, p<0.001). In conclusion, our results suggest that Mo from FL patients are predisposed to differentiate into an M2-like MΦ state. The interaction between lymphoma cells and Mo/MΦ is reciprocal: a change in Mo (MΦ differentiation) induced by interaction with lymphoma tumor cells leads to a change in the tumor cells (promotion of survival, proliferation, and chemoresistance). More importantly, our results demonstrate that targeting TAMs using CS4, an anti-CSF-1R mAb, can be an effective strategy to overcome the adverse effects of TAMs and reverse chemoresistance. Further studies are needed to determine whether STAT3 activation contributes to the protumor effects of TAMs. This may provide novel insights into the molecular mechanisms related to TAMs and lymphoma cells and offers additional targets for therapeutic development. In the long term, strategies targeting TAMs is especially appealing, as they should be able to be combined with existing therapies including chemotherapy, other immunotherapy, and targeted therapy, potentially improving their efficacy without increasing toxicity for FL, DLBCL, and other B-cell malignancies. Disclosures No relevant conflicts of interest to declare.

MiR-28 Silencing In Germinal Center-Derived Lymphomas

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 703-703
Author(s):  
Christof Schneider ◽  
Roy L Maute ◽  
Pavel Sumazin ◽  
Manisha Brahmachary ◽  
Manu Setty ◽  
...  
Keyword(s):  
B Cells ◽  
Tumor Suppressor ◽  
B Cell ◽  
Cell Lines ◽  
Mirna Expression ◽  
Germinal Center ◽  
Expression Profiling ◽  
B Cell Lymphoma ◽  
Lymphoma Cells

Abstract Abstract 703 In order to gain insights into the role of microRNA (miRNAs) in mature B cell function and lymphomagenesis, we performed a comprehensive miRNA expression profiling of normal mature B cells and of germinal center (GC)-derived lymphomas. miRNA expression profiles were generated using a commercial array platform designed to interrogate approximately 700 miRNAs. Normal GC B cells were isolated from tonsil tissue of 5 pediatric healthy donors and subjected to miRNA profiling in parallel with tumor specimens obtained from 10 Burkitt Lymphoma (BL), 16 Follicular Lymphoma (FL) and 20 Diffuse Large B Cell Lymphoma (DLBCL) patients. Each tumor type displayed a distinct miRNA profile and appeared to be clearly separated from the normal counterpart. Interestingly, a set of miRNAs was expressed in normal GC cells, but not in lymphoma samples, suggesting that structural and/or functional loss of miRNAs occur during lymphomagenesis. Among these, miR-28 was found to be up-regulated in GC B cells, while it was completely silenced in BL and significantly reduced in a large fraction of DLBCL and FL. Quantitative RT-PCR analysis confirmed miR-28 reduced expression in these GC-derived lymphoma subtypes including both primary biopsies and cell lines. MiR-28 is an intragenic miRNA encoded by the LPP gene locus, located on chromosome 3q28. Deletions affecting miR-28 and LPP were previously reported in FL (Schwaenen et al. Genes Chromosomes Cancer 2009; 48:39-54) and similarly we identified LPP deletions in about 9% of DLBCL investigated for copy number alterations by SNP arrays. Further FISH analyses performed in cell lines lacking miR-28 expression (12 DLBCL and 27 BL) failed to identify chromosomal aberrations in the LPP locus, suggesting that mechanisms other than genetic losses, possibly of epigenetic nature, are involved in miR-28 silencing in lymphomas. In order to investigate the effects of miR-28 in lymphoma cells, we generated stable lymphoma cell lines displaying inducible expression of miR-28. Re-expression of miR-28 in lymphoma cells led to a retarded growth due to a combination of G1-cell-cycle arrest and increased apoptosis. Furthermore, lymphoma cells expressing miR-28 lost their clonogenic properties as shown by their inability to form colonies in soft agar. Taken together these results suggest a tumor suppressor function for miR-28 in lymphoma cells. Toward the identification of the direct miR-28 target genes, we implemented computational target prediction methods with gene expression profiling data obtained from the miR-28 engineered cell lines. Approximately two thousand miR-28 direct candidate targets were computationally predicted, 88 of which displayed transcriptional down-regulation upon miR-28 induction, suggesting that miR-28 may affect the stability of the target transcript. The candidate targets included genes involved in the control of cell proliferation and apoptosis and in cell signaling, consistent with the phenotypic changes induced by miR-28 expression. In 4 out of 5 tested candidate targets, 3′-UTR reporter gene assay confirmed the direct effect of miR-28 on the target gene. Finally, we have generated a conditional, GC B cell-specific miR-28 knock-out mouse model, which will provide critical insights on the physiologic as well as the tumor suppressor role of miR-28 in vivo. Disclosures: No relevant conflicts of interest to declare.

scholarly journals The oncoprotein LMO2 is expressed in normal germinal-center B cells and in human B-cell lymphomas

Blood ◽  
2006 ◽  
Vol 109 (4) ◽  
pp. 1636-1642 ◽  
Author(s):  
Yasodha Natkunam ◽  
Shuchun Zhao ◽  
David Y. Mason ◽  
Jun Chen ◽  
Behnaz Taidi ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Cell Lines ◽  
Germinal Center ◽  
B Cell Lymphoma ◽  
Hierarchical Cluster ◽  
Tissue Expression ◽  
B Cell Lymphomas ◽  
Neoplastic Tissue ◽  
Associated Proteins

Abstract We previously developed a multivariate model based on the RNA expression of 6 genes (LMO2, BCL6, FN1, CCND2, SCYA3, and BCL2) that predicts survival in diffuse large B-cell lymphoma (DLBCL) patients. Since LMO2 emerged as the strongest predictor of superior outcome, we generated a monoclonal anti-LMO2 antibody in order to study its tissue expression pattern. Immunohistologic analysis of over 1200 normal and neoplastic tissue and cell lines showed that LMO2 protein is expressed as a nuclear marker in normal germinal-center (GC) B cells and GC-derived B-cell lines and in a subset of GC-derived B-cell lymphomas. LMO2 was also expressed in erythroid and myeloid precursors and in megakaryocytes and also in lymphoblastic and acute myeloid leukemias. It was rarely expressed in mature T, natural killer (NK), and plasma cell neoplasms and was absent from nonhematolymphoid tissues except for endothelial cells. Hierarchical cluster analysis of immunohistologic data in DLBCL demonstrated that the expression profile of the LMO2 protein was similar to that of other GC-associated proteins (HGAL, BCL6, and CD10) but different from that of non-GC proteins (MUM1/IRF4 and BCL2). Our results warrant inclusion of LMO2 in multivariate analyses to construct a clinically applicable immunohistologic algorithm for predicting survival in patients with DLBCL.

Acquisition of potential N-glycosylation sites in the immunoglobulin variable region by somatic mutation is a distinctive feature of follicular lymphoma

Blood ◽  
2002 ◽  
Vol 99 (7) ◽  
pp. 2562-2568 ◽  
Author(s):  
Delin Zhu ◽  
Helen McCarthy ◽  
Christian H. Ottensmeier ◽  
Peter Johnson ◽  
Terry J. Hamblin ◽  
...  
Keyword(s):  
Follicular Lymphoma ◽  
B Cell ◽  
Somatic Mutation ◽  
Germinal Center ◽  
Variable Region ◽  
B Cell Lymphoma ◽  
Single Chain ◽  
Single Chain Fv ◽  
Glycosylation Sites ◽  
Vh Genes

Most patients with follicular lymphoma (FL) have somatically mutated V genes with intraclonal variation, consistent with location in the germinal center site. Using our own and published sequences, we have investigated the frequency of potential N-glycosylation sites introduced into functional VH genes as a consequence of somatic mutation. FL cells were compared with normal memory B cells or plasma cells matched for similar levels of mutation. Strikingly, novel sites were detected in 55 of 70 (79%) patients with FL, compared to 7 of 75 (9%) in the normal B-cell population (P &lt; .001). Diffuse large B-cell lymphoma (DLCL) showed an intermediate frequency (13 of 32 [41%] patients). Myeloma and the mutated subset of chronic lymphocytic leukemia showed frequencies similar to those of normal cells in 5 of 64 (8%) patients and 5 of 40 (13%) patients, respectively. In 3 of 3 random patients with FL, immunoglobulin was expressed as recombinant single-chain Fv inPichia pastoris, and glycosylation was demonstrated. These findings indicate that N-glycosylation of the variable region may be common in FL and in a subset of DLCL. Most novel sites are located in the complementarity-determining regions. VH sequences of nonfunctional VH genes contained few sites, arguing for positive selection in FL. One possibility is that the added carbohydrate in the variable region contributes to interaction with elements in the germinal center environment. This common feature of FL may be critical for tumor behavior.

Acquirement of Rituximab Resistance Is Associated with the Development of Chemotherapy Resistance in B-Cell Lymphoma Cells: Evidence of Shared Pathways of Resistance between Chemotherapeutic Agents and Biological Therapies.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2297-2297
Author(s):  
Scott H. Olejniczak ◽  
Francisco J. Hernandez ◽  
Myron S. Czuczman
Keyword(s):  
B Cell ◽  
Cell Lines ◽  
Caspase 3 ◽  
Cell Lymphoma ◽  
Chemotherapy Resistance ◽  
B Cell Lymphoma ◽  
Parental Cell ◽  
Chemotherapeutic Agents ◽  
Lymphoma Cells ◽  
Apoptotic Effects

Abstract Pre-clinical studies have demonstrated that rituximab triggers apoptotic signals in B-cell lymphoma cells upon biding to CD20 antigen. Downstream signaling events observed in lymphoma cells following in vitro exposure of rituximab or chemotherapy include: 1) activation of the intrinsic apoptotic pathway and 2) increased mitogen activated protein kinase (MAPK) activity. In addition, pre-clinical and clinical studies strongly suggest that rituximab may sensitize lymphoma cells to apoptotic effects of various drugs used to treat NHL. Despite its anti-tumor activity, many patients relapse after initial response to rituximab-based therapy and demonstrate variable degrees of rituximab resistance. To further study the impact of rituximab resistance in cellular responses to chemotherapy we developed several rituximab resistant cell lines (RRCL) derived from Raji, SU-DHL-4 and RL cells by exposing cells to escalating doses of rituximab with (4RH cells) or without (2R cells) human serum. The rituximab resistance of each RRCL was confirmed by immunological assays. Subsequently, lymphoma cells (parental and RRCL) were exposed to various chemotherapeutic agents (cisplatin, doxorubicin, paclitaxel, or vincristine) for up to 48 hours. Detection of cell death was determined by trypan blue and/or propidium iodine staining. Caspase-3 activity was measured by PhiPhi Lux G1D2 enzymatic cleavage. Bcl-2 expression was determined by Western blotting. Chemotherapy resistance to all agents tested was observed in RRCL when compared to parental Raji, SU-DHL-4 and RL cell lines. In addition, caspase-3 activity was lower in RRCL following chemotherapy exposure than in parental cell lines. A significantly lower percent of RRCL cells within sub-G0/G1 peaks in cell cycle histograms confirmed that RRCL were less sensitive to chemotherapy-induced apoptosis. Additionally, an increase in Bcl-2 expression was observed in RRCL when compared parental cell lines. Our data strongly suggest that chemotherapy resistance emerges concomitantly with the acquirement of rituximab resistance in lymphoma cells. Chronic exposure to rituximab appears to cause overexpression of Bcl-2, which likely renders RRCL less susceptible to the apoptotic effects of chemotherapy agents. Ongoing studies are aimed at identifying and overcoming rituximab/chemotherapy shared cellular pathways of resistance.

Multiple Myeloma Oncogene 1 (MUM1)/Interferon Regulatory Factor 4 (IRF4) Upregulates Monokine Induced by Interferon-gamma (MIG) Gene Expression in B-Cell Malignancy.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 1111-1111
Author(s):  
Shinsuke Iida ◽  
Miyuki Uranishi ◽  
Takaomi Sanda ◽  
Takashi Ishida ◽  
Emi Tajima ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
B Cell ◽  
Cell Lines ◽  
Interferon Gamma ◽  
Zinc Finger Protein ◽  
B Cell Lymphoma ◽  
Interferon Regulatory Factor ◽  
Regulatory Factor ◽  
B Cell Lymphomas ◽  
Interferon Regulatory Factor 4

Abstract MUM1(multiple myeloma oncogene 1)/IRF4(interferon regulatory factor 4) is a transcription regulatory factor that is activated as a result of t(6;14)(p25;q32) in multiple myeloma. MUM1 expression is seen in various B-cell lymphomas/leukemias and has been reported to predict an unfavorable outcome in some lymphoma subtypes including diffuse large B-cell lymphoma (DLBCL) and B-cell chronic lymphocytic leukemia (B-CLL). To elucidate its role in B-cell malignancies, we prepared stably MUM1-expressing Ba/F3 cells, which proliferated at a higher rate than the parental cells, and performed cDNA microarray analysis to identify genes whose expression is regulated by MUM1. We found that the expression of four genes including FK506-binding protein 3 (FKBP3), the Monokine induced by interferon-gamma (MIG), Fas apoptotic inhibitory molecule (Faim) and Zinc finger protein 94 was altered in the MUM1-expressing cells. We then focused on MIG since its expression was immediately upregulated by MUM1 in inducible MUM1 expressing system. In reporter assays, MUM1 activated the MIG promoter in cooperation with PU.1, and the interaction between MUM1 and the MIG promoter sequence was confirmed in chromatin immunoprecipitation assay. The expression of MIG was correlated with that of MUM1 in B-CLL cell lines, and its receptor CXCR3 was also coexpressed in B-CLL cell lines that were positive for MUM1. Interestingly, treatment with neutralizing antibodies against MIG and its receptor, CXCR3, partially inhibited the proliferation of two MUM1-expressing B-CLL cell lines. These results suggest that MUM1 plays certain roles in the progression of B-cell lymphomas/leukemias by regulating the expression of various genes including MIG.

IL-4 Affects Proliferation, Chemosensitivity-and Rituximab Sensitivity of Germinal Center B-Cell like (GCB) and Activated B-Cell like (ABC) Diffuse Large B-Cell Lymphoma Differently.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 242-242 ◽  
Author(s):  
Hovav Nechushtan ◽  
Joseph D. Rosenblatt ◽  
Izidore S. Lossos
Keyword(s):  
Cell Death ◽  
B Cell ◽  
Cell Lines ◽  
Germinal Center ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Cell Lysis ◽  
Large B Cell Lymphoma ◽  
Expression Of Genes ◽  
Large B Cell

Abstract Diffuse Large B-cell Lymphoma (DLBCL) represent a diverse group of lymphoid neoplasms with heterogeneous clinical, histological, immunophenotypic, cytogenetic and molecular genetic features. Approximately 50% of DLBCL patients are not cured by the standard combination chemotherapy regimens. DLBCL can be subclassified into GCB-like DLBCL which are characterized by expression of genes normally expressed in germinal center B cells, and having a significantly better overall survival (OS) than the ABC-like DLBCL, which are characterized by expression of genes induced during in vitro activation of normal B cells. At least two markers of the GCB-phenotype - BCL6 and HGAL - are IL-4 target genes, increased expression of which independently predicts better OS. These observations suggest that endogenous or exogenously administered IL-4 may influence behavior of DLBCL. IL-4 mRNA was detected at low levels in 5 of 7 GCB-like and in all 4 ABC-like DLBCL tumor specimens. Two of 7 GCB-like tumors showed high expression levels of IL-4 as determined by real-time RT-PCR. Examination of the effects of IL-4 on proliferation of GCB-like (SUDHL6, SUDHL4 and OCILY19) and ABC-like (OCILY10 and OCILY3) DLBCL cell lines showed that IL-4 mildly increased DNA synthesis, as assessed by thymidine incorporation, in all the GCB-like DLBCL. Conversely, IL-4 markedly decreased proliferation in the ABC-like DLBCL cell lines by inducing G1 arrest. IL-4 also differently affected the sensitivity of GCB-like and ABC-like DLBCL to doxorubicin. IL-4 reduced doxorubicin-induced cell death of ABC-like cell lines (20–50% reduction) while it markedly increased the killing of the GCB-like cells (40–80% induction). IL-4 also prevented serum starvation-induced cell death of the ABC-like DLBCL, but it increased cell death of the GCB-like DLBCL cell lines. Recently, Rituximab was shown to improve survival of DLBCL patients when added to the CHOP regimen. The precise mechanisms of its action are unknown; however present data suggest that it may affect lymphoma cells either by activation of complement lysis or by mediating ADCC. IL-4 reduced the complement mediated Rituximab cell lysis of the ABC-like cell lines, while it increased the complement mediated Rituximab cell lysis of the GCB-like DLBCL cell lines. Expression levels of surface markers that modulate complement cell lysis (CD46, CD55 and CD59) were not affected by IL-4 exposure. In contrast, IL-4 did not affect killing of GCB-like and ABC-like cells by ADCC. These observations suggest that DLBCL subtypes may respond differently to the in vivo cytokine milieu of the tumor. Different responsiveness to IL-4 may modulate tumor sensitivity to the current therapeutic modalities and can potentially be explored to augment response to chemotherapy and Rituximab.

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