The Role of BCL-6 in Normal Lymphoid System and non-Hodgkin's Lymphomas

2003 ◽  
pp. 271-289
Author(s):  
B. Hilda Ye
1970 ◽  
Vol 245 (15) ◽  
pp. 3906-3910
Author(s):  
Asit K. Lahiri ◽  
William M. Mitchell ◽  
Victor A. Najjar

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 31-31
Author(s):  
Victor Yazbeck ◽  
Ian McConnell ◽  
Emily Harris ◽  
Joseph Lownik ◽  
Ariel Sindel ◽  
...  

Introduction: Indolent B-Cell Non-Hodgkin's Lymphomas (NHL) represent a heterogeneous group of lymphoproliferative malignancies, that remain largely incurable. Marginal zone lymphomas (MZL) are the second most common subtype of indolent NHL, and lack a unique cytogenetic identifying abnormality. The B-cell receptor signaling pathway is activated in B-cell malignancy and mediates its activity mainly through the Phosphoinositide 3-kinase (PI3K) pathway. Furthermore, novel PI3K inhibitors, such as copanlisib and parsaclisib, have shown impressive clinical activity in several indolent lymphomas including MZL. This further supports the important role of the PI3K pathway in the pathogenesis of this tumor. Therefore, we hypothesized that the PI3K-mTOR pathway is sufficient for driving the pathogenesis of MZL. Methods: In order to test our hypothesis, we generated a genetically engineered mouse model carrying heterozygous global knockout alleles of both the tumor suppressor genes Phosphatase and Tensin Homolog (PTEN) and Liver Kinase B1 (LKB1). This led to over-activation of the PI3K-mTOR pathway in all mouse tissues. We closely monitored these mice for tumor formation via weekly physical examinations for several months. Upon tumor detection, the mouse was sacrificed, and tumors were sectioned for histological characterization. In order to generate a more specific model of B cells, and more accurately mimic the underlying human disease, we used the Cre-LoxP system to create the CD19-Cre-PTENfl/fl-LKB1fl/fl. Results: Thirty mice of global KO PTEN+/- LKB1 +/- died or were sacrificed due to disease progression, defined as either lymph node enlargement and/or splenomegaly. All mice showed either abnormal lymphadenopathy or splenomegaly. By Kaplan-Meier analysis, we saw a steady decrease in both tumor-free and overall survival after 3 months of age. Utilizing the product limit method, the median survival time was 6 months (95% CI: 6, 8). A total of 51 lymph nodes were sent for immunohistochemistry and pathological characterization. Of the 51 nodes, 61.5% (N=32) showed indolent Non-Hodgkin's Lymphoma, 25% (N=13) were atypical, and 11.5% (N=6) were reactive. All lymph nodes with indolent NHL were of MZL subtype. Compared to wild type (n=3), the new CD19-Cre-PTENfl/fl -LKB1fl/fl (n=3) showed an overall increase in spleen mass (120 vs 196 mg, p=0.0564), % B1 cells (4% vs 59%, p= 0.0075), % MZ cells (5% vs 30%, p=0.0547), % plasma cells (1% vs 12%, p=0.0729), and decrease in % FO cells (80% vs 12%, p=0.0003) by flowcytometry. Further characterization of the new model is currently underway. Conclusion: Marginal zone lymphoma remains an incurable lymphoma that lacks reliable preclinical models. Our data provides, for the first time, a proof of concept on the role of the PI3K-mTOR pathway in the pathogenesis of marginal zone lymphoma and paves the way for future studies understanding the biology of this disease, and developing rational therapies for this incurable malignancy. Disclosures Yazbeck: Celgene: Consultancy; AstraZeneca: Consultancy; Gilead: Research Funding; Seattle Genetics: Consultancy; Verastem: Speakers Bureau.


2002 ◽  
Vol 88 (5) ◽  
pp. 400-406 ◽  
Author(s):  
Salvatore De Vita ◽  
Valli De Re ◽  
Domenico Sansonno ◽  
Annunziata Gloghini ◽  
Daniela Gasparotto ◽  
...  

Aims and background Preliminary evidence suggests that hepatitis C virus (HCV) might play a pathogenetic role in autoimmune-related, non-malignant B-cell lymphoproliferation, as well as in a subset of B-cell non-Hodgkin's lymphomas (NHLs). With regard to the mechanism(s) by which HCV might favor B-cell expansion and malignant transformation, most data support an indirect pathogenetic role of the virus as an exogenous trigger. A direct oncogenetic role of HCV by direct cell infection and deregulation has only been hypothesized on the basis of the lymphotropism of the virus. Methods In this study we investigated the possible HCV infection of NHL B cells by means of sensitive and quantitative polymerase chain reaction (PCR) on affinity-purified neoplastic cells, and by HCV-specific immunohistochemistry and in situ hybridization. Results HCV infection of neoplastic B cells was documented in only three cases, namely the low-grade B-cell NHLs that arose in the course of mixed cryoglobulinemia syndrome (MC). HCV infection, below one viral genome per cell, was detectable only by PCR. All the remaining low-grade (one case) and high-grade B-cell NHLs (two cases) were HCV uninfected. Previous immunoglobulin gene analyses were consistent with an antigen-driven B-cell lymphoproliferation in the studied cases. Conclusions Overall, our data are consistent with an indirect oncogenetic role of HCV in B-cell lymphomagenesis as an exogenous trigger. Infection of B cells by HCV appears possible in some NHL subsets, but the implications remain unknown.


Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 2371-2371
Author(s):  
Martin R. Mueller ◽  
Yoshiteru Sasaki ◽  
Sonia Sharma ◽  
Klaus Rajewsky ◽  
Anjana Rao

Abstract NFAT is a family of highly phosphorylated proteins residing in the cytoplasm of resting cells. Upon dephosphorylation by the Ca2+/calmodulin-dependent serine phosphatase calcineurin, NFAT translocates to the nucleus, where it induces the transcription of a large number of genes necessary for a productive immune response. NFAT signalling has also been implicated in lymphocyte homeostasis and its deregulation has been suggested to be involved in the pathogenesis of different malignancies. A recent immunohistochemical evaluation of approximately 300 Non-Hodgkin’s Lymphoma biopsy samples showed overexpression of NFAT2 in the majority of specimens with strong nuclear translocation in certain histologic subtypes (DLBCL, Burkitt’s Lymphoma) presumably reflecting activation of the NFAT pathway as part of their pathogenesis. Other recent studies have shown that NFAT activation leads to increased expression of different cell survival factors (CD154, BLyS) in several lymphoma subtypes (DLBCL, MCL). To study the role of constitutive activation of the NFAT pathway on lymphomagenesis, we generated several hyperactivable NFAT mutants which will be used to generate transgenic mice expressing the mutant proteins from the ROSA26 locus. Here, we present the in vitro characterization of these hyperactivable NFAT proteins in cell lines and primary lymphocytes. The major docking site for calcineurin is located at the N terminus of the NFAT regulatory domain and has the consensus sequence PxIxIT (e.g. SPRIEIT in NFAT1 and NFAT2). Substitution of the SPRIEIT sequence of NFAT with HPVIVIT, a higher-affinity version obtained by peptide selection, increases the basal calcineurin sensitivity of the protein significantly. Similarly, a major kinase for NFAT is CK1, and mutation of the CK1 docking site (FSILF to ASILA in NFAT1, FDFEF to ADAEA in NFAT2) also leads to partial nuclear localization of NFAT proteins by decreasing rephosphorylation and nuclear export. In the current analysis we compared the different hyperactivable NFAT proteins with respect to dephosphorylation status and nuclear translocation using western blotting and immunocytochemistry. Whereas the wildtype NFAT protein was entirely localized in the cytoplasm and completely phosphorylated under resting conditions, we observed an increasing degree of nuclear translocation and dephosphorylation for the different mutant proteins (ASILA 20%, VIVIT 30–40%, ASILA-VIVIT 50–70%). This system will allow us to study the impact of different levels of NFAT activation on the pathogenesis of lymphomas in vivo.


2000 ◽  
Vol 12 (5) ◽  
pp. 429-433 ◽  
Author(s):  
Dominique Dunon ◽  
Beat A. Imhof
Keyword(s):  

2008 ◽  
Vol 16 (3-4) ◽  
pp. 59-68 ◽  
Author(s):  
Vladimir Baltic ◽  
Milan Baltic ◽  
Zorica Svircev ◽  
Vera Jerant-Patic

MicroRNAs are a class of short, single-stranded, noncoding RNA molecules that negatively regulate the expression target mRNA at posttranslational level. microRNAs as key regulatory molecules play important biological function and might act as tumor suppressor oncogenes in cancer and lymphomas. microRNAs cause the expression of important cancer related genes and might prove useful in the diagnostics, prognosis, and treatment of some lymphomas This review focuses on the role of microRNAs in normal lymphocyte differentiation and in development of non-Hodgkin's lymphomas.


Blood ◽  
1995 ◽  
Vol 85 (8) ◽  
pp. 2182-2188 ◽  
Author(s):  
J Schwaller ◽  
A Tobler ◽  
G Niklaus ◽  
N Hurwitz ◽  
I Hennig ◽  
...  

Interleukin-12 (IL-12), a cytokine with in vitro and in vivo immunomodulatory effects, is produced by lymphocytes and stimulated monocytes. Little is known about the production and possible role of IL-12 in human lymphoproliferative disorders. We examined IL-12 expression by immunohistochemistry using antibodies recognizing the p40, p35 subunits, and the p70 heterodimeric IL-12 protein, and by Northern blot in lymph nodes from patients with Hodgkin's disease (HD), non-Hodgkin's lymphomas (NHL), and nonneoplastic lymphoid lesions. In the majority of the HD cases (28 of 34), IL-12 immunoreaction was found in small lymphoid cells cultured around Hodgkin and Reed-Sternberg (H&RS) cells. No IL-12 signal was seen in H&RS cells. Transcripts for IL-12 were found by Northern and dot blot analysis in 13 of 19 (IL-12 p40) and 11 of 19 (IL-12 p35) cases. The HD cases were further examined for the presence of Epstein-Barr virus (EBV) latent membrane protein (LMP-1). All cases with EBV-LMP-1 positivity (22 of 34 cases) also expressed IL- 12. No IL-12 immunoreaction was found in neoplastic cells of 33 cases of various NHLs, which were all LMP-1 negative and showed no EBV-genome sequence, as assessed by polymerase chain reaction (PCR). In 24 nonneoplastic lymphoid lesions, few dispersed IL-12 positive cells were seen in the parafollicular area and in the sinus of the lymph node. The marked presence of IL-12 in the majority of HD cases indicates that IL-12 might play a role in the pathobiology of HD, suggesting that this cytokine is involved in EBV-positive HD.


Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 3054-3054
Author(s):  
Roberto Guariglia ◽  
Stefano Luminari ◽  
Amalia De Renzo ◽  
Emilio Iannitto ◽  
Matteo Dell’Olio ◽  
...  

Abstract Antiviral therapy (AVT) with interferon +/− ribavirin can induce neoplastic regression without chemotherapy (CT) in low-grade non-Hodgkin’s lymphomas (in particular, immunocytomas and nodal/extranodal marginal lymphomas) with associated HCV infection (HCV+). High grade, diffuse large B-cell non- Hodgkin’s lymphomas (DLBCL) are HCV+ in about 12% of cases in Italian population. These patients show peculiar clinical characteristics, such as older age, liver damage, presence of monoclonal gammopathy (often with no clinically relevant cryoglobulinemic and/or rheumatoid activity), increased rate of autoimmune disorders and extranodal localizations. Their clinical outcome, however, is generally considered not significantly different, in terms of response rate, progression free survival (PFS) and overall survival (OS), from that of subjects with HCV negative (HCV−) DLBCL when treated with standard or even high dose CT and if significant signs of liver dysfunction are absent. In the present study we aimed to determine the possible role of AVT, performed after a standard CT treatment, in HCV+ DLBCL. We evaluated 40 HCV+ DLBCL patients (male/female ratio 25/15; median age 63 years, range 39–71) who received AVT after first complete (27 patients) or partial (13 patients) remission was achieved by frontline standard CT. Classic or modified CHOP+/− rituximab regimens were generally employed. Twenty-two patients (55%) showed a higher (3–4) IPI score and twenty patients (50%) evidenced increased ALT/AST values. A favourable HCV genotype (type 2–3) and a low viral load (< 600.000 copies) were observed in 19 (47.5%) and 15 (37.5%) patients, respectively. In the large majoriry of cases AVT consisted of peg-interferon 1 mg/kg (1.5 mg/kg for genotype 1) s.c. once-a-week, plus ribavirin 1000/1200 mg/d p.o., according to body-weight < or > 70/kg. A small number of patients received interferon-alpha with or without ribavirin. The planned duration of AVT ranged from 3 to 12 months and was modulated according to viral genotype and molecular response (genotype 2: 3 months, if viral clearance obtained after 1 month, otherwise continued for 6 months; other genotypes: 3 months of treatment with following suspension if viral clearance not obtained, otherwise continued for 12 months). Sequential treatment (CT followed by AVT) was generally well tolerated. Six patients, however, interrupted AVT before three months, mainly because of general malaise or myelotoxicity. HCV clearance was obtained in 22 patients (55%). A case-control comparison was made with a similar cohort of 40 HCV+ DBLCL patients, who did not receive AVT, matched for age, sex, IPI score, liver function, type of prior CT and response, viral load and HCV genotype. Three-year PFS was not statistically different between the two groups (52.5% vs 57.5%, p n.s.), while a trend in favour of AVT treated patients was observed in terms of three-year OS (67.5%% vs 57.5%, p=0.055). A weak correlation between viral clearance and longer OS duration was also observed (p=0.048). Interestingly, during the follow up period, severe hepatic failure developed in 5 (12.5%) out of patients who had not received AVT and in only one (2.5%) of those treated with AVT. Seventy-nine percent of relapsed patients not treated with AVT received salvage CT, compared to 100% of AVT treated patients. Our currently available data indicate that a sequential treatment with CT followed by AVT is feasible in HCV+ DLBCL and may induce complete virus clearance in more than half of these patients. We hypothesize that a better control of the viral infection, rather than a direct or indirect antineoplastic activity of AVT, could have positive effects on the clinical outcome of patients with HCV+ DLBCL and, possibly, on their survival, i.e. by allowing the possibility of further salvage therapies and reducing that of hepatic failure.


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