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Moloney murine leukemia virus (MLV) infects BALB/c mice and induces T-cell lymphoma in mice. Retroviral integration is mediated by the interaction of the MLV integrase (IN) with members of the bromodomain and extraterminal motif (BET) protein family (BRD2, BRD3, and BRD4). The introduction of the W390A mutation into MLV IN abolishes the BET interaction. Here, we compared the replication of W390A MLV to that of wild-type (WT) MLV in adult BALB/c mice to study the role of BET proteins in replication, integration, and tumorigenesis in vivo. Comparing WT and W390A MLV infections revealed similar viral loads in the blood, thymus, and spleen cells. Interestingly, W390A MLV integration was retargeted away from GC-enriched genomic regions. However, both WT MLV- and W390A MLV-infected mice developed T-cell lymphoma after similar latencies represented by an enlarged thymus and spleen and multiorgan tumor infiltration. Integration site sequencing from splenic tumor cells revealed clonal expansion in all WT MLV- and W390A MLV-infected mice. However, the integration profiles of W390A MLV and WT MLV differed significantly. Integrations were enriched in enhancers and promoters, but compared to the WT, W390A MLV integrated less frequently into enhancers and more frequently into oncogene bodies such as Notch1 and Ppp1r16b. We conclude that host factors direct MLV in vivo integration site selection. Although BET proteins target WT MLV integration preferentially toward enhancers and promoters, insertional lymphomagenesis can occur independently from BET, likely due to the intrinsically strong enhancer/promoter of the MLV long terminal repeat (LTR). IMPORTANCE In this study, we have shown that the in vivo replication of murine leukemia virus happens independently of BET proteins, which are key host determinants involved in retroviral integration site selection. This finding opens a new research line in the discovery of alternative viral or host factors that may complement the dominant host factor. In addition, our results show that BET-independent murine leukemia virus uncouples insertional mutagenesis from gene enhancers, although lymphomagenesis still occurs despite the lack of an interaction with BET proteins. Our findings also have implications for the engineering of BET-independent MLV-based vectors for gene therapy, which may not be a safe alternative. ispartof: MICROBIOLOGY SPECTRUM vol:10 issue:4 ispartof: location:United States status: published

Background A causative role of Coxiella burnetii (the causative agent of Q fever) in the pathogenesis of B-cell non-Hodgkin lymphoma (NHL) has been suggested, although supporting studies show conflicting evidence. We assessed whether this association is present by performing a detailed analysis on the risk of mature B-cell NHL after Q fever during and after the largest Q fever outbreak reported worldwide in the entire Dutch population over a 16-year period. Methods We performed an ecological analysis. The incidence of mature B-cell NHL in the entire Dutch population from 2002 until 2017 was studied and modelled with reported acute Q fever cases as the determinant. The adjusted relative risk of NHL after acute Q fever as the primary outcome measure was calculated using a Poisson regression. Results Between January 2002 and December 2017, 266 050 745 person-years were observed, with 61 424 diagnosed with mature B-cell NHL. In total, 4310 persons were diagnosed with acute Q fever, with the highest incidence in 2009. The adjusted relative risk of NHL after acute Q fever was 1.02 (95% CI 0.97–1.06, P = 0.49) and 0.98 (95% CI 0.89–1.07, P = 0.60), 0.99 (95% CI 0.87–1.12, P = 0.85) and 0.98 (95% 0.88–1.08, P = 0.67) for subgroups of diffuse large B-cell lymphoma, follicular lymphoma or B-cell chronic lymphocytic leukaemia, respectively. Modelling with lag times (1–4 years) did not change interpretation. Conclusion We found no evidence for an association between C. burnetii and NHL after studying the risk of mature B-cell NHL after a large Q fever outbreak in Netherlands.

TNF receptor-associated factor 3 (TRAF3) is an adapter protein that inhibits many signals that promote B cell survival and activation. Mice with a B cell-specific TRAF3 deficiency and humans with a rare haploinsufficiency in TRAF3 have enhanced development of BCLs as they age. Loss-of-function mutations in TRAF3 are common in B cell malignancies. Recent studies show that pharmacological inhibition of the enzyme glycogen synthase kinase 3 (GSK3), which regulates cellular growth, survival, and metabolism, inhibits growth and survival of BCL-derived B cells. In this study, we found that TRAF3 and GSK3 associated in B cells. The relative levels of TRAF3 in BCL cell lines correlated positively with the ratio of inactive to total GSK3β, and negatively correlated with susceptibility to GSK3 inhibition by the GSK3 inhibitory drug 9-ING-41, currently in clinical trials. Uniquely in BCLs with low TRAF3, GSK3 inhibition caused increased loss of the TRAF3-regulated, anti-apoptotic protein Mcl-1. GSK3 inhibition also blocked hyperresponsiveness to IL-6 receptor signaling in TRAF3-deficient BCL cells. Together, these results support the utility of 9-ING-41 as a treatment for BCL, and suggest that a decrease or loss of TRAF3 in BCLs could act as a biomarker for increased susceptibility to GSK3 inhibitor treatment.

The association of HCV-infection with B-lymphomas is supported by the regression of most indolent/low-grade lymphomas following anti-viral therapy. Studies on direct and indirect oncogenic mechanisms have elucidated the pathogenesis of HCV-associated B-lymphoma subtypes. These include B-lymphocyte proliferation and sustained clonal expansion by HCV-envelope protein stimulation of B-cell receptors, and prolonged HCV-infected B-cell growth by overexpression of an anti-apoptotic BCL-2 oncogene caused by the increased frequency of t(14;18) chromosomal translocations in follicular lymphomas. HCV has been implicated in lymphomagenesis by a "hit-and-run" mechanism, inducing enhanced mutation rate in immunoglobulins and anti-oncogenes favoring immune escape, due to permanent genetic damage by double-strand DNA-breaks. More direct oncogenic mechanisms have been identified in cytokines and chemokines in relation to NS3 and Core expression, particularly in diffuse large B-cell lymphoma. By reviewing genetic alterations and disrupted signaling pathways, we intend to highlight how mutually non-contrasting mechanisms cooperate with environmental factors towards progression of HCV-lymphoma.

Summary One of the unusual features of germinal center (GC) B cells is that they manifest many hallmarks of cancer cells. Accordingly, most B‐cell neoplasms originate from the GC reaction, and characteristically display abundant point mutations, structural genomic lesions, and clonal diversity from the genetic and epigenetic standpoints. The dominant biological theme of GC‐derived lymphomas is mutation of genes involved in epigenetic regulation and immune receptor signaling, which come into play at critical transitional stages of the GC reaction. Hence, mechanistic studies of these mutations reveal fundamental insight into the biology of the normal and malignant GC B cell. The BCL6 transcription factor plays a central role in establishing the GC phenotype in B cells, and most lymphomas are dependent on BCL6 to maintain survival, proliferation, and perhaps immune evasion. Many lymphoma mutations have the commonality of enhancing the oncogenic functions of BCL6, or overcoming some of its tumor suppressive effects. Herein, we discuss how unique features of the GC reaction create vulnerabilities that select for particular lymphoma mutations. We examine the interplay between epigenetic programming, metabolism, signaling, and immune regulatory mechanisms in lymphoma, and discuss how these are leading to novel precision therapy strategies to treat lymphoma patients.

B lymphocytes are an indispensable part of the human immune system. They are the effective mediators of adaptive immunity and memory. To accomplish specificity against an antigen, and to establish the related immunologic memory, B cells differentiate through a complicated and strenuous training program that is characterized by multiple drastic genomic modifications. In order to avoid malignant transformation, these events are tightly regulated by multiple checkpoints, the vast majority of them involving bioenergetic alterations. Despite this stringent control program, B cell malignancies are amongst the top ten most common worldwide. In an effort to better understand malignant pathobiology, in this review, we summarize the metabolic swifts that govern normal B cell lymphopoiesis. We also review the existent knowledge regarding malignant metabolism as a means to unravel new research goals and/or therapeutic targets.

The Epstein–Barr virus (EBV) is a well-adapted human virus, and its infection is exclusive to our species, generally beginning in the childhood and then persisting throughout the life of most of the affected adults. Although this infection generally remains asymptomatic, EBV can trigger life-threatening conditions under unclear circumstances. The EBV lifecycle is characterized by interactions with other viruses or bacteria, which increases the probability of awakening its pathobiont capacity. For instance, EBV infects B cells with the potential to alter the germinal center reaction (GCR)—an adaptive immune structure wherein mutagenic-driven processes take place. HIV- and Plasmodium falciparum-induced B cell hyperactivation also feeds the GCR. These agents, along with the B cell tropic KSHV, converge in the ontogeny of germinal center (GC) or post-GC lymphomas. EBV oral transmission facilitates interactions with local bacteria and HPV, thereby increasing the risk of periodontal diseases and head and neck carcinomas. It is less clear as to how EBV is localized in the stomach, but together with Helicobacter pylori, they are known to be responsible for gastric cancer. Perhaps this mechanism is reminiscent of the local inflammation that attracts different herpesviruses and enhances graft damage and chances of rejection in transplanted patients. In this review, we discussed the existing evidence suggestive of EBV possessing the potential to synergize or cooperate with these agents to trigger or worsen the disease.

// Estibaliz Tamayo-Orbegozo 1 , Laura Amo 1 , Marta Rinon 1 , Naiara Nieto 2 , Elena Amutio 3 , Natalia Maruri 1 , Miren Solaun 4 , Arantza Arrieta 1 and Susana Larrucea 1 1 Regulation of the Immune System Group, BioCruces Health Research Institute, Hospital Universitario Cruces, Barakaldo, Bizkaia, Spain 2 Cell Culture Unit, BioCruces Health Research Institute, Hospital Universitario Cruces, Barakaldo, Bizkaia, Spain 3 Hematology and Hemotherapy Service, BioCruces Health Research Institute, Hospital Universitario Cruces, Barakaldo, Bizkaia, Spain 4 Flow Cytometry Unit, BioCruces Health Research Institute, Hospital Universitario Cruces, Barakaldo, Bizkaia, Spain Correspondence to: Susana Larrucea, email: slarrucea@osakidetza.eus Keywords: podocalyxin, lymphomagenesis, obinutuzumab resistance, glutaminolysis, pentose phosphate pathway Received: December 23, 2016 Accepted: August 17, 2017 Published: September 27, 2017 ABSTRACT Podocalyxin (PCLP1) is a CD34-related sialomucin expressed by some normal cells and a variety of malignant tumors, including leukemia, and associated with the most aggressive cancers and poor clinical outcome. PCLP1 increases breast tumor growth, migration and invasion; however, its role in hematologic malignancies still remains undetermined. The purpose of this study was to investigate the expression and function of PCLP1 in mature B-cell lymphoma cells. We found that overexpression of PCLP1 significantly increases proliferation, cell-to-cell interaction, clonogenicity, and migration of B-cell lymphoma cells. Furthermore, PCLP1 overexpression results in higher resistance to death induced by dexamethasone, reactive oxygen species and type II anti-CD20 monoclonal antibody obinutuzumab. Strikingly, enforced expression of PCLP1 enhances lipid droplet formation as well as pentose phosphate pathway and glutamine dependence, indicative of metabolic reprogramming necessary to support the abnormal proliferation rate of tumor cells. Flow cytometry analysis revealed augmented levels of PCLP1 in malignant cells from some patients with mature B-cell lymphoma compared to their normal B-cell counterparts. In summary, our results demonstrate that PCLP1 contributes to proliferation and survival of mature B-cell lymphoma cells, suggesting that PCLP1 may promote lymphomagenesis and represents a therapeutic target for the treatment of B-cell lymphomas.

Introduction: MYC hyperactivation and genetic lesions affecting B-cell receptor and NFkB signaling have been described in recent years to be central features of aggressive non-Hodgkin-lymphoma. Yet little is currently known about the capacity of NFkB and B-cell receptor-associated lesions to drive lymphoma in co-operation with MYC and how they affect cell signaling and phenotype of manifest disease. Additionally, it is still not understood how MYD88L265P, NFKBIZ, CD79BY196H, CARD11L244P and PD-L1 affect the interaction between lymphoma cells and the immune system. Methods: We approached those enigmas of lymphoma biology using two transplantation models in which the transplanted cells were retrovirally transduced with genetic lesions MYD88L265P, NFKBIZ, CD79BY196H, CARD11L244P and PD-L1: (i) stem cell transplantation of retrovirally transduced Eµ-myc transgenic fetal liver cells as a source of hematopoietic stem cells to study lymphomagenesis and (ii) a retransplantation approach of retrovirally transduced manifest Eµ-myc lymphomas as model systems to study the lymphoma biology in vivo. For functional analysis of these models, we used histopathological, biochemical and classical molecular biology approaches, FACS, microscopy-coupled FACS, transcriptome and metabolomics analyses. Results: Of these in vivo approaches, NFKBIZ and MYD88L265P were found to be highly Eµ-myc co-operative genetic lesions in contrast to CARD11L244P in the fetal liver cell approach. NFKBIZ and MYD88L265P-driven lymphomas were found to form transcriptionally clustering and distinguishable entities compared to empty control Eµ-myc lymphomas. PD-L1 was found to be able to drive lymphoma in co-operation with Eµ-myc in the fetal liver cell model and was identified as an important mechanism contributing to lymphoma aggressiveness in MYD88L265P-driven Eµ-myc lymphomas. Overexpression of PD-L1 in the transplantation model of Eµ-myc transgenic fetal liver cell-induced lymphomas. Regarding the inability of CARD11L244P to drive lymphoma in our model, we found CARD11L244P-induced senescence to be a critical principle preventing lymphomagenesis. Conclusion: Our systematic in vivo analysis of different lesions indicated that MYD88L265P and NFKBIZ cooperate with Myc while CARD11L244P requires upfront senescence-ablating lesions to license Myc-driven lymphomagenesis. Immune evasive mechanisms were found to be central aspects of MYD88L265P driven lymphomas with an increase of PD-L1 expression as an important mechanism. Altogether these investigations provide mouse models of MYD88L265P, PD-L1 and NFKBIZ driven lymphomas, a mechanistic analysis of the MYD88L265P-NFKBIZ-PD-L1 triangle in aggressive lymphoma biology and senescence as a central barrier in CARD11L244P-driven lymphomagenesis., Einleitung: In den letzten Jahren wurde im aggressiven non-Hodgkin Lymphom gezeigt, dass die Hyperaktivierug von MYC und genetische Läsionen innerhalb immunologischer Signalkaskaden wesentliche Merkmale dieser Krankheitsentität darstellen. Im Moment ist wenig über das Zusammenspiel dieser Signalkaskaden mit MYC in der Lymphomgenese bekannt. Zudem ist es immer noch unklar, wie MYD88L265P, NFKBIZ, CD79BY196H, CARD11L244P und PD-L1 die Interaktion aggressiver Lymphome mit dem Immunsystem beeinflussen. Methoden: Um die aufgeworfenen Fragen beantworten zu können, nutzten wir zwei Transplantationsmodelle, bei denen die transplantierten Zellen jeweils retroviral mit genetischen Läsionen transduziert wurden, welche in humanen agressiven Lymphomen beschrieben wurden: (i) die Transplantation von retroviral transduzierten Eμ-myc transgenen murinen fetalen Leberzellen als Quelle hämatopoietischer Stammzellen, um die Lymphomgenese in vivo zu untersuchen und (ii) die Transplantation retroviral transduzierter, manifester murine Eμ-myc Lymphome, um die Lymphombiologie in vivo zu untersuchen. Dabei wurden histopathologische Untersuchungen, klassisch 3 molekularbiologische Methoden, Fluoreszenzmikroskopie gekoppelte FACS Analysen sowie RNA Sequenzierung und Metabolom Analysen genutzt Ergebnisse: Aus diesen in vivo Untersuchungen ergab sich, dass MYD88L265P und NFKBIZ im Gegensatz zu CARD11L244P wesentlich mit Eμ-myc in der Lymphomgenese zusammenwirken. Auf transkriptionaler Ebene zeigte sich, dass NFKBIZ und MYD88L265P getriebene und Leervektor Eμ-myc Lymphome transkriptional klar voneinander unterscheidbare Entitäten darstellten. Bei der Modellierung und Untersuchung des Einflusses von PD-L1 auf die Biologie aggressiver Lymphome zeigte sich, dass PD-L1 sowohl ein zentraler Regulator der Interaktion zwischen Lymphom und Immunsystem ist als auch wesentlich auf intrazelluläre Signalkaskaden der Lymphomzellen wirkt. Die Überexpression von PD-L1 generierte im Zusammenspiel mit Eμ-myc ebenfalls Lymphome im fetalen Leberzellmodell. Bezüglich der nicht onkogenen Eigenschaften von CARD11L244P im Zusammenspiel mit Eμ-myc zeigte sich, dass onkogen-induzierte Seneszenz dies in unserem System verhindert. Schlussfolgerung: Unsere systematische in vivo Analyse verschiedener genetischer Läsionen zeigte, dass MYD88L265P und NFKBIZ mit Myc kooperieren, wohingegen CARD11L244P initiale Seneszenzdefekte benötigt, um mit Myc in der Lymphomgenese zusammenzuarbeiten. Wir konnten feststellen, dass immunevasive Mechanismen zur MYD88L265P-getriebenen Lymphomgenese im fetalen Leberzellmodell beitragen. PD-L1 ist hierfür eine wichtige Schaltstelle. Insgesamt werden in dieser Arbeit die ersten Mausmodelle für PD-L1- und NFKBIZ- getriebene Lymphome und eine mechanistische Analyse der MYD88L265P–NFKBIZ- PD-L1 Interaktionen in der Biologie aggressiver Lymphome dargelegt. Zudem wird Seneszenz als zentrale Barriere, welche die Lymphomgenese durch CARD11L244P im Eμ-myc Modell verhindert, dargestellt.

Background DNA methylation regulates gene transcription in many physiological processes in mammals including development and haematopoiesis. It is catalysed by several DNA methyltransferases, including Dnmt3b that mediates both methylation-dependant and independent gene repression. Dnmt3b is critical for mouse embryogenesis and functions as a tumour suppressor in haematologic malignancies in mice. However, the extent to which Dnmt3b's catalytic activity (CA) is involved in development and cancer is unclear. Methods We used a mouse model expressing catalytically inactive Dnmt3b (Dnmt3bCI) to study a role of Dnmt3b's CA in development and cancer. We utilized global approaches including Whole-genome Bisulfite sequencing and RNA-seq to analyse DNA methylation and gene expression to identify putative targets of Dnmt3b's CA. To analyse postnatal development and haematopoiesis, we used tissue staining, histological and FACS analysis. To determine potential involvement of selected genes in lymphomagenesis, we used overexpression and knock down approaches followed by in vitro growth assays. Findings We show that mice expressing Dnmt3bCI only, survive postnatal development and develop ICF (the immunodeficiency-centromeric instability-facial anomalies) -like syndrome. The lack of Dnmt3b's CA promoted fibroblasts transformation in vitro, accelerated MLL-AF9 driven Acute Myeloid Leukaemia and MYC-induced T-cell lymphomagenesis in vivo. The elimination of Dnmt3b's CA resulted in decreased methylation of c-Met promoter and its upregulation, activated oncogenic Met signalling, Stat3 phosphorylation and up-regulation of Lin28b promoting lymphomagenesis. Interpretation Our data demonstrates that Dnmt3b's CA is largely dispensable for mouse development but critical to prevent tumourigenesis by controlling events involved in cellular transformation. Funding This study was supported by Department of Anatomy and Cell Biology and Cancer Centre at the University of Florida start-up funds, NIH/NCI grant 1R01CA188561-01A1 (R.O.).

// Nour Ghazzaui 1,* , Alexis Saintamand 1,* , Hussein Issaoui 1 , Christelle Vincent-Fabert 1 and Yves Denizot 1 1 Universite de Limoges, Centre National de la Recherche Scientifique, CNRS UMR, France * These authors have have contributed equally to this work Correspondence to: Yves Denizot, email: // Keywords : c-myc, 3’ regulatory region, lymphomagenesis, transgenic mice, HDAC Received : August 15, 2016 Accepted : October 05, 2016 Published : October 08, 2016 Abstract Deregulation and mutations of c-myc have been reported in multiple mature B-cell malignancies such as Burkitt lymphoma, myeloma and plasma cell lymphoma. After translocation into the immunoglobulin heavy chain (IgH) locus, c-myc is constitutively expressed under the control of active IgH cis -regulatory enhancers. Those located in the IgH 3’ regulatory region (3’RR) are master control elements of transcription. Over the past decade numerous convincing demonstrations of 3’RR’s contribution to mature c-myc-induced lymphomagenesis have been made using transgenic models with various types of IgH-c-myc translocations and transgenes. This review highlights how IgH 3’RR physiological functions play a critical role in c-myc deregulation during lymphomagenesis.

// Tara L. Peters 1 , Lingxiao Li 2 , Ana A. Tula-Sanchez 3 , Praechompoo Pongtornpipat 4 , Jonathan H. Schatz 2 1 Sheila and David Fuente Graduate Program in Cancer Biology, Division of Hematology-Oncology, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL, USA 2 Department of Medicine, Division of Hematology-Oncology, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL, USA 3 Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ, USA 4 Bio5 Institute, University of Arizona, Tucson, AZ, USA Correspondence to: Jonathan H. Schatz, email: jschatz@miami.edu Keywords: ABC-DLBCL, PIM kinase, cap-dependent translation, B-cell receptor signaling, lymphomagenesis Received: October 05, 2015 Accepted: August 05, 2016 Published: August 20, 2016 ABSTRACT The PIM family kinases promote growth and survival of tumor cells and are expressed in a wide variety of human cancers. Their potential as therapeutic targets, however, is complicated by overlapping activities with multiple other pathways and remains poorly defined in most clinical scenarios. Here we explore activity of the new pan-PIM inhibitor PIM447 in a variety of lymphoid-derived tumors. We find strong activity in cell lines derived from the activated B-cell subtype of diffuse large B-cell lymphoma (ABC-DLBCL). Sensitive lines show lost activation of the mTORC1 signaling complex and subsequent lost activation of cap-dependent protein translation. In addition, we characterize recurrent PIM1 protein-coding mutations found in DLBCL clinical samples and find most preserve the wild-type protein’s ability to protect cells from apoptosis but do not bypass activity of PIM447. Pan-PIM inhibition therefore may have an important role to play in the therapy of selected ABC-DLBCL cases.

The human BCL6 gene, which is involved in the pathogenesis of certain human lymphomas, encodes a transcriptional repressor that is needed for germinal center B cell development and T follicular helper cell differentiation. Our goal was to identify BCL6 target genes using a cell system in which BCL6 repressive effects are inhibited followed by subtractive hybridization, and we detected the RUVBL1 (Pontin, TIP49) gene as a potential target of BCL6 repression. Here we show that the BCL6 protein significantly represses RUVBL1 transcription (6.8-fold). Knockdown of endogenous BCL6 in a human B cell lymphoma line leads to significant upregulation of RUVBL1, and there is an inverse expression pattern between the BCL6 and RUVBL1 proteins in certain human lymphomas. RUVBL1 is part of the AAA+ superfamily and participates in multiple processes, including gene transcription regulation, chromatin remodeling, and DNA repair, which, if dysregulated, may promote lymphoma development. A further understanding of the relationship between RUVBL1 and BCL6 should improve our understanding of the pathogenesis of human lymphomas., Highlights • BCL6, a transcriptional repressor, is deregulated in human lymphomas. • The RUVBL1 (Pontin, TIP49) gene is a target of BCL6 repression. • Regulation of RUVBL1 by BCL6 may be important in lymphomagenesis.

The balance between cell survival and cell death represents an essential part of human tissue homeostasis, while altered apoptosis contributes to several pathologies and can affect the treatment efficacy. Impaired apoptosis is one of the main cancer hallmarks and some types of lymphomas harbor mutations that directly affect key regulators of cell death (such as BCL-2 family members). The development of novel techniques in the field of immunology and new animal models has greatly accelerated our understanding of oncogenic mechanisms in MYC-associated lymphomas. Mouse models are a powerful tool to reveal multiple genes implicated in the genesis of lymphoma and are extensively used to clarify the molecular mechanism of lymphoma, validating the gene function. Key features of MYC-induced apoptosis will be discussed here along with more recent studies on MYC direct and indirect interactors, including their cooperative action in lymphomagenesis. We review our current knowledge about the role of MYC-induced apoptosis in B-cell malignancies, discussing the transcriptional regulation network of MYC and regulatory feedback action of miRs during MYC-driven lymphomagenesis. More importantly, the finding of new modulators of apoptosis now enabling researchers to translate the discoveries that have been made in the laboratory into clinical practice to positively impact human health.

One of the most important determinants of aging-related changes is a complex biological process emerged recently and called “immunosenescence”. Immunosenescence refers to the inability of an aging immune system to produce an appropriate and effective response to challenge. This immune dysregulation may manifest as increased susceptibility to infection, cancer, autoimmune disease, and vaccine failure. At present, the relationship between immunosenescence and lymphoma in elderly patients is not defined in a satisfactory way. This review presents a brief overview of the interplay between aging, cancer and lymphoma, and the key topic of immunosenescence is addressed in the context of two main lymphoma groups, namely Non Hodgkin Lymphoma (NHL) and Hodgkin Lymphoma (HL). Epstein Barr Virus (EBV) plays a central role in the onset of neoplastic lymphoproliferation associated with immunological changes in aging, although the pathophysiology varies vastly among different disease entities. The interaction between immune dysfunction, immunosenescence and Epstein Barr Virus (EBV) infection appears to differ between NHL and HL, as well as between NHL subtypes.

Lymphoma is one of the most common malignancies in domestic cats. The lymphomagenicpotential of Felis catus gammaherpesvirus 1 (FcaGHV1), a common infection in domestic cats,is unknown. In other species, including humans, cellular transformation by gammaherpesvirusesis typically mediated by viral genes expressed during latency. We analysed tumour RNA, fromdiffuse large B-cell lymphomas (DLBCL) appearing in cats coinfected with FcaGHV1 and felineimmunodeficiency virus (FIV) (n = 10). Analysis was done by high throughput transcriptomesequencing and reverse transcription PCR. A limited repertoire of FcaGHV transcripts was identifiedin five tumors, including homologs of oncogenic latency-associated transcripts, latency-associatednuclear antigen (LANA, ORF73) and vFLIP (F7), lytic genes (ORF50, ORF6, ORF59, F10), and an ORFunique to FcaGHV1, F20. In situ hybridization of FIV-associated DLBCLs (n = 9), post-transplantlymphomas (n = 6) and high-grade B and T-cell intestinal lymphomas (n = 8) identified a single casein which FcaGHV1 nucleic acid was detectable. These results demonstrate that FcaGHV1 transcriptscan be detected in some FIV-associated lymphomas, but with a low copy number, precludingassessment of a potential role for FcaGHV1 in lymphomagenesis. Future investigation of the FcaGHV1transcriptome in clinical samples might employ viral enrichment and greater sequencing depth toenhance the retrieval of viral reads. Our results suggest prioritization of a subset of intestinal T-celltumors and large granular lymphocyte lymphoma, for study.

Despite antiretroviral therapy, HIV+ individuals still have increased risk to develop lymphomas, including marginal zone lymphomas, suggesting that factors other than HIV-related immunosuppression are probably acting as lymphomagenic factors in the HIV setting. The possible pathogenic involvement of HIV p17 protein variants was investigated in a particularly informative case of HIV-related splenic marginal zone lymphoma, which was negative for oncogenic virus infections, thus allowing us to assess the possible direct contribution of these HIV-encoded proteins to lymphomagenesis. The presence of p17 protein was analyzed by immunohistochemistry in lymphoma tissue. Recombinant p17 protein derived from the dominant sequence detected in plasma and lymphoma biopsy was characterized for B-cell proliferation, clonogenicity in soft agar, in vitro tube formation and wound healing. Intracellular signaling was investigated by immunoblotting. HIV p17 protein was detected in reactive lymphoid follicles but not within lymphoma cells. An identical dominant variant p17 sequence, p17-Lyrm, carrying a 117 to 118 Ala-Ala insertion was detected in both plasma and lymphoma tissue. Recombinant p17-Lyrm enhanced B-cell proliferation and clonogenicity promoted the formation of capillary-like structures and enhanced endothelial cell migration. Unlike reference p17, the p17-Lyrm variant enhanced the activation of Akt and ERK, critical kinases in lymphomagenesis. p17-Lyrm clonogenic activity was dependent on the activation of Akt but not of ERK1/2. These results indicated that HIV p17 variants with distinct molecular signatures and functional properties may accumulate in lymphoid tissues of HIV-infected individuals where they may act as a local stimulus promoting the development of lymphomas.

Background Development of non-Hodgkin's lymphoma (NHL) is the major adverse outcome of primary Sjogren's Syndrome (pSS) affecting both morbidity and mortality. The high frequency of transformation to lymphoid malignancy in pSS among autoimmune rheumatic diseases (6-10% of patients) and the accessibility of the affected organ (minor salivary glands; MSG), render pSS an ideal model for the study of lymphomagenesis associated with autoimmune diseases and inflammation. Although pSS-related lymphoid transformation is generally considered as an antigen-driven, multi-step process owed to the chronic activation of B-cells in MSGs, the underlying mechanisms remain elusive. Our recent results support that miR200b-5p miRNA is significantly down-regulated in the MSGs of pSS patients who have or will develop lymphoma, long before lymphoma clinical onset, indicating that it may be involved in lymphomagenesis. Aim To investigate the role of miR200b-5p miRNA in pSS-associated lymphomagenesis. Methods At first, the miR200b-5p-expression will be examined by in situ hybridization in MSGs of pSS patients who are at low risk and have not developed NHL during follow-up, high risk and developed NHL in the future (pre-lymphoma) or have NHL, and the expressing cellular types, as well as those with reduced expression during lymphomagenesis, will be identified. Then, the miR200b-5p targeted molecular pathways in those cellular types (epithelial, B-cells and/or other lymphocytes, all non-neoplastic) will be studied in in vitro experiments by over-expressing and silencing of miR200b-5p, followed by transcriptome analysis. This approach is expected to find possibly novel pathogenetic mechanisms underlying SS-related lymphomagenesis. The latter is of high significance, not only for the understanding of lymphomagenesis, but also for its reversal and/or treatment. Anticipated benefits This approach is anticipated to a) reveal the differentially regulated molecules and pathways by miR200b-5p, b) enlighten novel pathogenetic pathways underlying lymphomagenesis and c) identify novel therapeutic targets and possibly evidence-based therapeutic interventions.

Cernunnos/XLF deficiency is a rare primary immunodeficiency classified within the DNA repair defects. Patients present with severe growth retardation, microcephaly, lymphopenia and increased cellular sensitivity to ionizing radiation. Here, we describe two unrelated cases with the same non-sense mutation in the NHEJ1 gene showing significant differences in clinical presentation and immunological profile but a similar DNA repair defect.

CD300A is a type I transmembrane receptor protein which has shown inhibitory effects on B-cell receptor-mediated signals. In an analysis of public dataset, we found that CD300A mRNA levels were inversely correlated with the overall survival time of patients with diffuse large B-cell lymphoma (DLBCL). To decipher the role of CD300A in DLBCL, we knocked down the expression levels of CD300A in DLBCL cells and found that decreasing levels of CD300A significantly inhibited cell proliferation of OCI-Ly01, Farage, and SUDHL-4 cells, but not of VAL, OCI-Ly10, or SUDHL-8 cells. Mechanistically, reduced expression of CD300A resulted in a marked attenuation of AKT phosphorylation, a key molecular event in tumorigenesis, in OCI-Ly01, Farage, and SUDHL-4 cells. Pharmacologic inhibition of PI3K displayed a similar inhibitory effect on cell proliferation. Furthermore, using a xenograft animal model, we found that decreasing levels of CD300A in OCI-Ly01 and Farage cells significantly inhibited tumor formation in vivo. Collectively, our results suggested an oncogenic role of CD300A in DLBCL which could serve as a potential biomarker and therapeutic target for this malignant disease.

Overexpression of BCLX and BFL1/A1 has been reported in various human malignancies and is associated with poor prognosis and drug resistance, identifying these prosurvival BCL2 family members as putative drug targets. We have generated transgenic mice that express human BFL1 or human BCLX protein throughout the haematopoietic system under the control of the Vav gene promoter. Haematopoiesis is normal in both the Vav-BFL1 and Vav-BCLX transgenic (TG) mice and susceptibility to spontaneous haematopoietic malignancies is not increased. Lymphoid cells from Vav-BCLX TG mice exhibit increased resistance to apoptosis in vitro while most blood cell types form Vav-BFL1 TG mice were poorly protected. Both transgenes significantly accelerated lymphomagenesis in Eμ-MYC TG mice and, surprisingly, the Vav-BFL1 transgene was the more potent. Unexpectedly, expression of transgenic BFL1 RNA and protein is significantly elevated in B lymphoid cells of Vav-BFL1/Eμ-MYC double-transgenic compared to Vav-BFL1 mice, even during the preleukaemic phase, providing a rationale for the potent synergy. In contrast, Vav-BCLX expression was not notably different. These mouse models of BFL1 and BCLX overexpression in lymphomas should be useful tools for the testing the efficacy of novel human BFL1- and BCLX-specific inhibitors.

Mantle cell lymphoma (MCL) is characterized by an aggressive clinical course and secondary resistance to currently available therapies in most cases. Therefore, despite recent advances in the treatment of this disease, it is still considered to be incurable in the majority of cases. MCL B cells retain their B cell antigen receptor (BCR) expression during and after neoplastic transformation. BCRs in MCL show distinct patterns of antigen selection and ongoing BCR signaling. However, little is known about the involved antigens and the mechanisms leading to lymphomagenesis and lymphoma progression in MCL. Recent preclinical and clinical studies have established a crucial role of the BCR and the potential of inhibiting its signaling in this disease. This has established the B cell antigen receptor signaling cascade as a very promising therapeutic target to improve outcome in MCL alone or in combination with chemo-immunotherapy in recent years.

Immune deficiency and altered immunity are among the best characterized and strongest known risk factors of non-Hodgkin lymphomas (NHL). For instance, chronic inflammation or certain disturbances in the immune system are associated with an increased lymphoma risk. Occupational and environmental factors (i.e., dioxin) as well as lifestyle factors (i.e., obesity) may contribute to these risk factors. The precise role of these factors in the etiology of NHL, however, is still not entirely clear. Although the existing epidemiologic studies have not revealed consistent patterns of perturbations of the immune system by these factors, the findings might suggest an adverse impact on both the humoral and cell-mediated immune system.

Notch signaling pathway regulates a wide variety of cellular processes during development and it also plays a crucial role in human diseases. This important link is firmly established in cancer, since a rare T-ALL-associated genetic lesion has been initially reported to result in deletion of Notch1 ectodomain and constitutive activation of its intracellular region. Interestingly, the cellular response to Notch signaling can be extremely variable depending on the cell type and activation context. Notch signaling triggers signals implicated in promoting carcinogenesis and autoimmune diseases, whereas it can also sustain responses that are critical to suppress carcinogenesis and to negatively regulate immune response. However, Notch signaling induces all these effects via an apparently simple signal transduction pathway, diversified into a complex network along evolution from Drosophila to mammals. Indeed, an explanation of this paradox comes from a number of evidences accumulated during the last few years, which dissected the intrinsic canonical and non-canonical components of the Notch pathway as well as several modulatory extrinsic signaling events. The identification of these signals has shed light onto the mechanisms whereby Notch and other pathways collaborate to induce a particular cellular phenotype. In this article, we review the role of Notch signaling in cells as diverse as T lymphocytes and epithelial cells of the epidermis, with the main focus on understanding the mechanisms of Notch versatility.

Lymphangiogenesis and concurrent angiogenesis are essential in supporting proliferation and survival of AIDS-related lymphomas, which are often metastatic. In vitro studies suggest a candidate angiogienic and lymphangiogenic factor encoded by HIV: the matrix protein p17. p17 accumulates in lymph nodes of patients even when they are undergoing highly active antiretroviral therapy. p17 has been found to affect immune cells, and recent data showed that a variant p17, called S75X, induces cell growth by triggering MAPK/ERK and PI3K/AKT pathways. We tested the in vivo angiogenic activity of p17 by injecting it in Matrigel plugs in nude mice. Plugs were retrieved 7 days after injection, and assessed macroscopically, and by light and confocal microscopy. Our data revealed that both reference and S75X variant p17 promote angiogenesis and lymphangiogenesis in vivo. Our results suggest that the induction of angiogenesis and lymphangiogenesis by HIV-1 p17 may generate a favorable microenvironment that could trigger tumor growth and maintenance. Moreover, the presence of adipocytes infiltration observed at the histological level suggests a possible interplay between angiogenesis, lymphangiogenesis and adipogenesis. These findings offer new opportunities for the development of treatment strategies to combat HIV-related cancers.

Background Insulin enhancer binding protein-1 (ISL-1), a LIM-homeodomain transcription factor, is essential for the heart, motor neuron and pancreas development. Recently, ISL-1 has been found in some types of human cancers. However, how ISL-1 exerts the role in tumor development is not clear. Methods and results The expression of ISL-1 was assessed in 211 human lymphoma samples and 23 normal lymph node samples. Immunohistochemistry results demonstrated a markedly higher expression of ISL-1 in 75% of non-Hodgkin lymphoma (NHL) samples compared with that in normal lymph nodes or Hodgkin lymphoma (HL) samples. CCK-8 analysis, cell cycle assay and xenograft model were performed to characterize the association between ISL-1 expression level and biological functions in NHL. The results showed that ISL-1 overexpression obviously promoted NHL cells proliferation, changed the cell cycle distribution in vitro and significantly enhanced xenografted lymphoma development in vivo. Real-time PCR, Western blot, luciferase assay and ChIP assay were used to explore the potential regulatory targets of ISL-1 and the results demonstrated that ISL-1 activated the c-Myc expression in NHL by direct binding to a conserved binding site on the c-Myc enhancer. Further results revealed that ISL-1 could be positively regulated by the c-Jun N-terminal kinase (JNK) and the Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathways. Both the JNK and JAK/STAT signaling inhibitors could significantly suppressed the growth of NHL cells through the down-regulation of ISL-1 as demonstrated by CCK-8 and Western blot assays. Bioinformatic analysis and luciferase assay exhibited that ISL-1 was a novel target of p-STAT3 and p-c-jun. ChIP, Co-IP and ChIP-re-IP analysis revealed that ISL-1 could participate with p-STAT3 and p-c-Jun to form a p-STAT3/p-c-Jun/ISL-1 transcriptional complex that binds directly on the ISL-1 promoter, demonstrating a positive feedback regulatory mechanism for ISL-1 expression in NHL. Conclusions Our results provide the first evidence that ISL-1 is tightly linked to NHL proliferation and development by promoting c-Myc transcription, and its aberrant expression was regulated by p-STAT3/p-c-Jun/ISL-1 complex activation.

HIV infection increases the risk of many types of cancer, including lymphoma. Combination antiretroviral therapy (cART) has reduced, but not eliminated, the risk of HIV-associated lymphoma. There has been a substantial shift in the subtypes of lymphoma observed in HIV-infected patients treated with cART. In this review, we will first outline these changes based on epidemiological studies and describe the impact of cART on lymphoma risk and mortality. Then, we will discuss some immunological factors that may contribute to the increased risk of lymphoma persisting after the administration of cART, including immunological non-response to therapy, chronic B-cell activation and dysfunction, T follicular helper cells, natural killer cells and altered lymphopoiesis. A better understanding of the pathophysiologic mechanisms of HIV-associated lymphoma under effective cART will inform future treatment strategies.

PubMedID: 14508793 Hepatitis C virus (HCV) is an RNA virus in the Flaviviridae family. It displays lymphotropism in addition to hepatotropism and extrahepatic manifestations are very well known. There are many studies showing an association between HCV infection and non-Hodgkin's lymphomas (NHL). In this study the evidence for HCV infection was studied in cases with NHL. To this end, anti-HCV antibody and HCV-RNA were screened in serum samples of cases with NHL using third-generation ELISA and RT-PCR. Anti-HCV antibody was studied in 223 patients and was found to be positive in 18 cases (8.1%). Anti-HCV antibody positivity was compared with our blood bank/blood donor population. There was an important increased risk of HCV infection - the common odds ratio was 34.56 and corrected odds ratio was 19.07. HCV-RNA was studied in 67 of 223 serum samples. HCV-RNA was found to be positive in 21 of 67 samples (31.3%). When compared with clinico-demographic parameters for anti-HCV and HCV-RNA, including age, nodal status, and grade (in evaluable cases), except age in cases with or without HCV-RNA, we did not find an important correlation with HCV status and clinical findings (P = 0.155; 0.442; 0.288 for anti-HCV and 0.027; 0,558; 0.126, respectively). These results suggest that HCV infection may be an important risk factor for lymphomagenesis and HCV-RNA is more useful for the detection of HCV infection in these immunosuppressed cases. Simultaneous detection of anti-HCV and HCV-RNA will be more informative in this population. © 2003 Wiley-Liss, Inc.

Лимфома Беркитта встречается с большей частотой среди ВИЧ- инфицированных пациентов по сравнению со здоровыми людьми. Эта закономерность может быть связана с иммуносупрессией и значительным уменьшением количества CD4-клеток у людей, больных СПИДом. Однако есть данные и о прямом влиянии вируса на пролиферацию и дифференцировку B-клеток. Возможные механизмы ассоциации ВИЧ с лимфомой Беркитта могут включать в себя как взаимодействие самого вируса с B-клетками, так и роль различных компонентов вириона и вирусных белков (Tat, Nef, gp120, оболочка вируса). В миниобзоре обсуждается влияние ВИЧ и белков ВИЧ на транслокацию c-myc/IgH, характерную для клеток лимфомы Беркитта. Ключевые слова: лимфома Беркитта, возникновение лимфом, ВИЧ-1. Лімфома Беркітта з високою частотою зустрічається серед ВІЛ- інфікованих пацієнтів порівняно зі здоровими людьми. Така закономірність може бути пов’язана з імуносупресією і значним зменшенням кількості CD4-клітин у людей, хворих на СНІД. Однак є відомості і щодо прямого впливу вірусу на проліферацію та диференціювання B-клітин. Можливі механізми асоціації ВІЛ з лімфомою Беркітта можуть включати як взаємодію самого вірусу з B-клітинами, так і роль різних компонентів віріона і вірусних білків (Tat, Nef, gp120, оболонка вірусу). В мініогляді обговорюється вплив ВІЛ і білків ВІЛ на транслокацію c-myc/IgH, характерну для клітин лімфоми Беркітта. Ключові слова: лімфома Беркітта, утворення лімфом, ВІЛ-1. The risk of Burkitt lymphoma (BL) is increased in HIV-infected patients as compared to general population in Europe and in the US. This effect might be due to immune suppression and low CD4-cell counts associated with the development of AIDS. However, there is also evidence of a direct effect of HIV on B cell proliferation and differentiation, which may account for the development of B cell malignancies. We shall discuss possible mechanisms of implication of HIV in BL with a focus on the role of different viral components (Tat, Nef and gp120 proteins, viral envelope) in the c-myc/IgH translocation characteristic of BL. Keywords: Burkitt lymphoma, lymphomagenesis, HIV-1.

Genetic variants of the three-prime repair exonuclease 1 (TREX1) -an exonuclease involved in DNA repair and degradation- have been previously found to increase susceptibility to Aicardi Goutieres syndrome, familial chilblain lupus and systemic lupus erythematosus. We aimed to explore whether TREX1 common variants could influence the risk of primary Sjogren’s syndrome (SS) and SS-related lymphoma. Three single nucleotide polymorphisms (SNPs) of the TREX1 gene (rs11797, rs3135941 and the rs3135945) were evaluated in 229 SS, 89 SS-lymphoma (70 SS-MALT and 19 SS non-MALT) and 240 healthy controls by PCR-based assays. In available 52 peripheral blood and 26 minor salivary gland tissues from our SS cohort, mRNA expression of type I interferon (IFN) related genes and TREX1 was determined by real-time PCR. Significantly decreased prevalence of rs11797 A minor allele was detected in SS patients complicated by non-MALT lymphoma compared to controls (ΟR [95% CI]: 0.4 [0.2-0.9], p-value: 0.02). SS patients carrying the rs11797 AA genotype had increased type I IFN related gene mRNA expression in minor salivary gland tissues. These data support genetically related dampened type I IFN production as an additional mechanism for SS-related lymphomagenesis.

Genetic variants of the three-prime repair exonuclease 1 (TREX1) -an exonuclease involved in DNA repair and degradation- have been previously found to increase susceptibility to Aicardi Goutieres syndrome, familial chilblain lupus and systemic lupus erythematosus. We aimed to explore whether TREX1 common variants could influence the risk of primary Sjogren’s syndrome (SS) and SS-related lymphoma. Three single nucleotide polymorphisms (SNPs) of the TREX1 gene (rs11797, rs3135941 and the rs3135945) were evaluated in 229 SS, 89 SS-lymphoma (70 SS-MALT and 19 SS non-MALT) and 240 healthy controls by PCR-based assays. In available 52 peripheral blood and 26 minor salivary gland tissues from our SS cohort, mRNA expression of type I interferon (IFN) related genes and TREX1 was determined by real-time PCR. Significantly decreased prevalence of rs11797 A minor allele was detected in SS patients complicated by non-MALT lymphoma compared to controls (ΟR [95% CI]: 0.4 [0.2-0.9], p-value: 0.02). SS patients carrying the rs11797 AA genotype had increased type I IFN related gene mRNA expression in minor salivary gland tissues. These data support genetically related dampened type I IFN production as an additional mechanism for SS-related lymphomagenesis.