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Lymphoma Cell Lines (lymphoma + cell_line)
Selected AbstractsDifferential effects of US2, US6 and US11 human cytomegalovirus proteins on HLA class,Ia and HLA-E expression: impact on target susceptibility to NK cell subsetsEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 10 2003Manuel Llano Abstract We compared in an inducible expression system the individual effect of US2, US6 and US11 human cytomegalovirus (HCMV) proteins on HLA-E and HLA class,Ia surface expression, assessing in parallel their influence on target susceptibility to NK cell clones. To this end, the RPMI,8866 B,lymphoma cell line (HLA-A2, HLA-A3, HLA-B7, HLA-Cw7, HLA-ER, HLA-EG) was stably cotransfected with the ecdysone receptor, together with the US sequences under the control of an ecdysone-inducible promoter. Biosynthesis of viral proteins was turned on by incubating transfectants with Ponasterone,A. US6 down-regulated expression of all class,I molecules, hampering target resistance to NK cell clones controlled by the CD94/NKG2A, KIR2DL2 and/or CD85j (ILT2 or LIR-1) inhibitory receptors. By contrast, US11 reduced the surface levels of class,Ia molecules but preserved HLA-E; this rendered US11+ cells sensitive to NK clones under the control of KIR2DL2 and/or CD85j, while their resistance to CD94/NKG2A+KIR2DL2, effector cells was maintained. US2 preserved as well HLA-E expression but selectively targeted class,Ia molecules; in fact, HLA-A and HLA-C allotypes were down-modulated whereas HLA-B7 remained unaltered. US2+ targets became sensitive to KIR2DL2+ cells but remained resistant to CD94/NKG2A+CD85j+ NK clones. The differential effects of US proteins on HLA class,Ia and HLA-E likely reflect the evolutionary adaptation of HCMV to counteract NK-mediated surveillance. [source] Analysis of phosphatase and tensin homolog tumor suppressor interacting proteins by in vitro and in silico proteomicsPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 5 2005David K. Crockett Abstract The phosphatase and tensin homolog (PTEN) tumor suppressor is a multifunctional protein deregulated in many types of cancer. To date, a comprehensive documentation of PTEN interacting proteins has not been performed. The goal of our study was to characterize the PTEN interactome using affinity pull-down and tandem mass spectrometry (MS/MS). Wild-type PTEN cDNA was inserted into pTRC-His2 vector to create a 6-His tagged protein, which was expressed in Escherichia coli. Lysate from a human lymphoma cell line was used in pull-down assays, utilizing affinity for nickel-agarose beads. Bound proteins were eluted with imidazole, digested and analyzed on an LCQ DecaXP ion trap mass spectrometer. The nickel affinity pull-down efficiency was evaluated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot analysis. Acquired data were searched against the NCBI nr.fasta nonredundant protein database using the SEQUEST algorithm and screened using INTERACT and ProteinProphet. All experiments were performed in duplicate with 6-His- lacZ serving as control. A total of 79 proteins were identified in the wild-type 6-His-PTEN pull-down by MS/MS. We further validated a subset of the proteins present in the PTEN interactome by performing immunoprecipitation using an anti-PTEN antibody and establishing the presence of the proteins in the immunocomplex by Western blot analysis. A search of published PTEN interactions was also performed using Online Mendelian Inheritance in Man, Human Protein Reference Database, the IntAct Project database, and PubMed. This in silico analysis confirmed 42 out of 79 (53%) of the proteins identified by MS/MS. The remaining 37 proteins represent probable PTEN interactions not previously documented in public databases or reported in the literature. These results highlight the value of combining both in vitro biochemical approaches with in silico analyses for a comprehensive study of protein-protein interactions. [source] PAX5 activates the transcription of the human telomerase reverse transcriptase gene in B cells,THE JOURNAL OF PATHOLOGY, Issue 1 2010Stéphanie Bougel Abstract Telomerase is an RNA-dependent DNA polymerase that synthesizes telomeric DNA. Its activity is not detectable in most somatic cells but it is reactivated during tumorigenesis. In most cancers, the combination of hTERT hypermethylation and hypomethylation of a short promoter region is permissive for low-level hTERT transcription. Activated and malignant lymphocytes express high telomerase activity, through a mechanism that seems methylation-independent. The aim of this study was to determine which mechanism is involved in the enhanced expression of hTERT in lymphoid cells. Our data confirm that in B cells, some T cell lymphomas and non-neoplastic lymph nodes, the hTERT promoter is unmethylated. Binding sites for the B cell-specific transcription factor PAX5 were identified downstream of the ATG translational start site through EMSA and ChIP experiments. ChIP assays indicated that the transcriptional activation of hTERT by PAX5 does not involve repression of CTCF binding. In a B cell lymphoma cell line, siRNA-induced knockdown of PAX5 expression repressed hTERT transcription. Moreover, ectopic expression of PAX5 in a telomerase-negative normal fibroblast cell line was found to be sufficient to activate hTERT expression. These data show that activation of hTERT in telomerase-positive B cells is due to a methylation-independent mechanism in which PAX5 plays an important role. Copyright © 2009 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. [source] Synergism between fludarabine and rituximab revealed in a follicular lymphoma cell line resistant to the cytotoxic activity of either drug aloneBRITISH JOURNAL OF HAEMATOLOGY, Issue 4 2001N. Di Gaetano We have shown previously that the anti-CD20 chimaeric monoclonal antibody rituximab exerts its effects on neoplastic B-lymphoma cell lines in part via complement-dependent cytotoxicity. In addition, membrane expression levels of complement inhibitory proteins CD55 and CD59 play a role in determining susceptibility to lysis. We have identified one t(14;18)-positive human B-cell non Hodgkin's lymphoma cell line (Karpas 422) that is resistant to rituximab and complement and used it for subsequent studies on the possible interaction between this novel therapeutic agent and established antineoplastic drugs. We have exposed Karpas to several chemotherapeutic agents (doxorubicin, idarubicin, cisplatin, taxol) for different time periods and subsequently exposed the cells to rituximab and human complement. The combination of these drugs with rituximab induced an additive cytotoxic effect. In contrast, exposure to fludarabine (1 µg/ml for 48,72 h) showed a synergistic effect, with cell lysis increasing from 10% to 20% using fludarabine or rituximab and complement alone to about 70% with both cytotoxic agents. Analysis of the mechanism for this synergistic effect showed that fludarabine downmodulates the membrane expression of CD55 (from 96% to 55% positive cells) without significantly altering CD20 levels. Northern analysis demonstrated that fludarabine induced a general downmodulation of steady state mRNA levels with no change in transcription rate detected in run-off assays. The study of the effect of fludarabine and rituximab in six freshly isolated B-cell chronic lymphocytic leukaemia (B-CLL) samples showed that, in most cases, fludarabine has an additive cytotoxic activity with rituximab and complement. This report gives a rational support for clinical studies with combinations of drugs, including monoclonal antibodies and fludarabine. [source] Sample pooling in 2-D gel electrophoresis: A new approach to reduce nonspecific expression backgroundELECTROPHORESIS, Issue 22 2006Marc Weinkauf Abstract Protein expression alterations unrelated to an investigated phenotype are accumulated in most cell line models during establishment. Performing a whole proteome screening of lymphoma cell lines, we established a method to reduce the influence of protein expression unrelated to the distinct investigated phenotype. In 2-D PAGE, the comprehensive analysis of a large number of protein spots would be simplified by pooling cell line samples of the investigated phenotype. Applying this pooling approach, unrelated alterations of single samples are ,muted' by dilution. Analysing two different lymphoma subtypes (follicular and mantle cell lymphoma) by this method, spots originating in only single cell lines were reduced by 72% (650/900), whereas even modestly altered expression of protein spots detected in all lines were reliably detected in the pooled protein gels. We conclude that our pooling approach is a preferable approach to reliably detect a common protein expression pattern and may even allow proteomic analysis of clinical samples with limited amounts of sample material, even with minimal cell numbers as low as 1×106. [source] Molecular cytogenetic characterization of non-Hodgkin lymphoma cell linesGENES, CHROMOSOMES AND CANCER, Issue 3 2002Sukvarsha Mehra Spectral karyotyping (SKY) and comparative genomic hybridization (CGH) have greatly enhanced the resolution of cytogenetic analysis, enabling the identification of novel regions of rearrangement and amplification in tumor cells. Here we report the analysis of 10 malignant non-Hodgkin lymphoma (NHL) cell lines derived at the Ontario Cancer Institute (OCI), Toronto, designated as OCI-Ly1, OCI-Ly2, OCI-Ly3, OCI-LY4, OCI-Ly7, OCI-Ly8, OCI-Ly12, OCI-Ly13.2, OCI-Ly17, and OCI-Ly18, by G-banding, SKY, and CGH, and we present their comprehensive cytogenetic profiles. In contrast to the 52 breakpoints identified by G-banding, SKY identified 87 breakpoints, which clustered at 1q21, 7p15, 8p11, 13q21, 13q32, 14q32, 17q11, and 18q21. G-banding identified 10 translocations, including the previously described recurring translocations, t(8;14)(q24;q32) and t(14;18)(q32;q21). In contrast, SKY identified 60 translocations, including five that were recurring, t(8;14)(q24;q32), t(14;18)(q32;q21), t(4;7)(p12;q22), t(11;18)(q22;q21), and t(3;18)(q21;p11). SKY also identified the source of all the marker chromosomes. In addition, 10 chromosomes that were classified as normal by G-banding were found by SKY to be rearranged. CGH identified seven sites of high-level DNA amplification, 1q31-32, 2p12-16, 8q24, 11q23-25, 13q21-22, 13q32-34, and 18q21-23; of these, 1q31-32, 11q23-25, 13q21-22, and 13q32-34 have previously not been described as amplified in NHL. This comprehensive cytogenetic characterization of 10 NHL cell lines identified novel sites of rearrangement and amplification; it also enhances their value in experimental studies aimed at gene discovery and gene function. © 2002 Wiley-Liss, Inc. [source] Specific thermal ablation of tumor cells using single-walled carbon nanotubes targeted by covalently-coupled monoclonal antibodiesINTERNATIONAL JOURNAL OF CANCER, Issue 12 2009Radu Marches Abstract CD22 is broadly expressed on human B cell lymphomas. Monoclonal anti-CD22 antibodies alone, or coupled to toxins, have been used to selectively target these tumors both in SCID mice with xenografted human lymphoma cell lines and in patients with B cell lymphomas. Single-walled carbon nanotubes (CNTs) attached to antibodies or peptides represent another approach to targeting cancer cells. CNTs convert absorbed near-infrared (NIR) light to heat, which can thermally ablate cells that have bound the CNTs. We have previously demonstrated that monoclonal antibodies (MAbs) noncovalently coupled to CNTs can specifically target and kill cells in vitro. Here, we describe the preparation of conjugates in which the MAbs are covalently conjugated to the CNTs. The specificity of both the binding and NIR-mediated killing of the tumor cells by the MAb-CNTs is demonstrated by using CD22+CD25, Daudi cells, CD22,CD25+ phytohemagglutinin-activated normal human peripheral blood mononuclear cells, and CNTs covalently modified with either anti-CD22 or anti-CD25. We further demonstrate that the stability and specificity of the MAb-CNT conjugates are preserved following incubation in either sodium dodecyl sulfate or mouse serum, indicating that they should be stable for in vivo use. © 2009 UICC [source] Rapid induction of apoptosis in B-cell lymphoma by functionally isolated human antibodiesINTERNATIONAL JOURNAL OF CANCER, Issue 2 2006Johan Fransson Abstract Novel panning and screening methodology was devised to isolate high affinity human recombinant scFv antibody fragments with functionally associated properties in B lymphoma cells. The approach was used to generate a panel of apoptosis-inducing antibodies specific for antigens differentially expressed in B lymphoma vs. T leukaemia cells. The selections resulted in an antibody pool with near perfect selectivity (>99%) for the B lymphoma target cells. Randomly picked clones (72) revealed 7 unique antibody genotypes. Six of these rapidly induced apoptosis in target cells. Following the conversion to full IgGs, the antibodies were shown to be specific for HLA-DR/DP, the B-cell receptor , chain and for CD54/ICAM-1. The latter receptor was not previously associated with apoptotic properties in B-cell lymphomas. Anti-ICAM-1 IgG induced apoptosis in a broad range of B lymphoma cell lines and were shown by immunohistochemistry to bind strongly to B lymphoma tissue obtained from 5 different B lymphoma patients. The recombinant IgG antibodies had affinities in the subnanomolar (0.3 nM) to nanomolar (3 nM) range. The described technology is generally applicable for the rapid isolation of high affinity human antibodies with specificity for differentially expressed cell surface receptors with intrinsic negative or positive signalling properties from naïve phage libraries. © 2006 Wiley-Liss, Inc. [source] CD137 and CD137 ligand constitutively coexpressed on human T and B leukemia cells signal proliferation and survivalINTERNATIONAL JOURNAL OF CANCER, Issue 3 2004Carla Palma Abstract CD137, a member of the tumor necrosis factor receptor family, provides expansion and survival signal to T cells. Its ligand, CD137L, in addition to its ability to costimulate T cells, signals back into antigen presenting cells promoting their activation and differentiation. Recently, CD137 has been proposed as a therapeutic target to improve and sustain anticancer immune response. Several activated T leukemia and B lymphoma cell lines expressed CD137 or CD137L, respectively, and soluble CD137L has been found in sera of leukemia patients. However, the functionality and role of these costimulatory molecules in hematologic malignancies are until now unknown. Interestingly, we observed constitutive CD137 and CD137L coexpression on both human T and B leukemia cell lines. The constitutive CD137 expression on unstimulated T or B leukemia cells presents some differences compared to CD137 expressed on PMA/ionomycin-activated T leukemia cells. Surprisingly, in spite of the low expression level, both tumor CD137 and CD137L molecules signaled in T and B leukemia cells inducing proliferation and prolonging survival. In addition, CD137/CD137L system ligation opposed the anticancer drug cytotoxic effects, reducing the apoptotic DNA fragmentation and stimulating proliferation of doxorubicin-escaped leukemia cells. Although the role of leukemia CD137/CD137L system in vivo is unknown, these data suggest that these costimulatory molecules might confer an advantage to hematologic tumors promoting survival, sustaining cellular growth and contributing to drug resistance. © 2003 Wiley-Liss, Inc. [source] Alternatively spliced transcripts of Fas mRNAs in feline lymphoid cellsINTERNATIONAL JOURNAL OF IMMUNOGENETICS, Issue 4 2004T. Mizuno Summary Fas belongs to the tumour necrosis factor receptor family and transduces the death signal after binding to the Fas ligand. Five feline lymphoma cell lines were shown, by reverse transcription,polymerase chain reaction, to express six species of Fas transcripts. Based on sequence comparison of these Fas transcripts with the genomic Fas gene, five of the six transcripts were found to be generated through alternative splicing and to encode five different Fas proteins lacking the transmembrane domain. We also detected such alternatively spliced transcripts in primary tumour tissues from cats with naturally occurring lymphoma. These results suggest a possible association of the alternatively spliced Fas variants with the pathogenesis of feline lymphoma. [source] Molecular cloning of feline tumour necrosis factor receptor type I (TNFR I) and expression of TNFR I and TNFR II in lymphoid cells in catsINTERNATIONAL JOURNAL OF IMMUNOGENETICS, Issue 2 2003T. Mizuno Summary Tumour necrosis factor (TNF)-, is a pro-inflammatory cytokine produced by many types of cells. It has been shown that two distinct TNF receptors (TNFRs), TNFR type I (TNFR I) and TNFR type II (TNFR II), have different functions in signal transduction, which is possibly associated with the development of a variety of diseases. In this study, we isolated a feline TNFR I cDNA clone and analysed the expression of TNFR I and TNFR II mRNA in feline lymphoid cells. The deduced amino acid sequence of feline TNFRI cDNA showed 75.8, 62.5 60.9 and 72.1% similarity with those of its human, mouse, rat, and pig counterparts, respectively. The feline TNFR I cDNA was shown to encode extracellular, transmembrane and intracellular domains fundamentally conserved in the homologues of other species. Expression of TNFR I and TNFR II mRNAs was shown to be up-regulated in feline peripheral blood mononuclear cells (PBMC) by stimulation with concanavalin A. Five of six feline lymphoma cell lines were shown to express both TNFR I and TNFR II mRNAs. The expression of TNFR I in PBMC was up-regulated in cats infected with feline immunodeficiency virus (FIV), whereas the expression of TNFR II in PBMC was not different between FIV-infected cats and uninfected cats. The present study indicate that expression of TNFR I and TNFR II may be associated with disease progression, especially in retrovirus infections in cats. [source] An animal model for Epstein,Barr virus (EBV)-associated lymphomagenesis in the human: Malignant lymphoma induction of rabbits by EBV-related herpesvirus from cynomolgusPATHOLOGY INTERNATIONAL, Issue 2 2000Kazuhiko Hayashi It is very important to develop and analyze animal models of Epstein,Barr virus (EBV)-associated tumors in the human. However, only a few reports on the animal models of EBV infection have been reported. Here we review those previous models and describe the details on our newly developed rabbit model of malignant lymphoma induced by EBV-related virus from cynomolgus. In brief, Si-IIA-EBV or Cyno-EBV induced T-cell lymphomas in rabbits inoculated intravenously (77,90%), orally (82,89%), subcutaneously (3/3) and intraperitoneally (2/3) about 2,5 months later. EBV-DNA was detected in peripheral blood by polymerase chain reaction 2 days after oral inoculation of Cyno-EBV while antiviral capsid antigen immunoglobulin G (IgG) was raised 3 weeks after the inoculation. Rabbit lymphomas and their cell lines contained EBV-DNA and expressed EBV-encoded small RNA-1 and EBV-associated nuclear antigen. Rabbit lymphoma cell lines, some of which have specific chromosomal abnormality, showed tumorigenicity in nude mice. The significance and further research subjects of this animal model will be discussed. We believe that the present rabbit model of lymphoma with specific chromosomal abnormalities is very useful for clarifying the role of EBV in human EBV-associated lymphoma and provides a means for studying prophylactic and therapeutic regimens. [source] Involvement of macroautophagy in the caspase-independent killing of Burkitt lymphoma cell lines by rituximabBRITISH JOURNAL OF HAEMATOLOGY, Issue 1 2009Julie Turzanski First page of article [source] Role of CD21 antigen in diffuse large B-cell lymphoma and its clinical significanceBRITISH JOURNAL OF HAEMATOLOGY, Issue 4 2004Masaki Otsuka Summary Recent advances in immunological and molecular technology have prompted proposals to change tumour classification and treatment strategies. Cell surface antigens are now easy to access, and tumour origins and clinical characteristics are now readily identifiable. However, in diffuse large B-cell lymphoma (DLBCL), one of the heterogeneous forms of haematological malignancy, the clinical significance of tumour surface antigens has not been well documented. We analysed the tumour surface antigens of 50 tumours from newly diagnosed DLBCL patients by flow cytometry in accordance with their clinical characteristics and followed the patients for a median 3·7 years. Statistical analysis showed that CD21 expression was significantly negatively associated with mortality in DLBCL (CD21 negative versus positive; relative risk = 2·36, P < 0·05). As a result of these clinical observations, we generated CD21-overexpressed (CD21+) lymphoma cell lines after gene transfection and analysed tumour cell growth in vivo in immunocompromised mice. Mice challenged with vector-only transfectants and parental cells as controls died within 50 d. In contrast, mice injected with CD21+ transfectants exhibited significantly reduced tumour growth and 83% survived long term (versus control groups; P < 0·05). Interestingly, all established CD21+ transfectants (six clones from different bulks) showed homotypic aggregation during in vitro cell culture, and anti-CD21 antibodies did not block this aggregation. Expression of CD21 is strongly associated with increased survival in DLBCL in vivo. CD21 expression may be indirectly concerned with the expression of additional cell adhesion molecules. [source] Impairment of double-strand breaks repair and aberrant splicing of ATM and MRE11 in leukemia,lymphoma cell lines with microsatellite instabilityCANCER SCIENCE, Issue 3 2006Maria Francisca Ham Mutations of DNA double-strand breaks (DSB) repair genes, ATM, MRE11, RAD50, NBS1 and ATR, are postulated to play a role in the development of gastrointestinal malignancies with an impaired mismatch repair (MMR) function. In the present study, mutations of these genes together with the presence of microsatellite instability (MSI) were examined in 50 leukemia,lymphoma cell lines. MSI was detected in 13 (26%) lines. Mutations of intronic mononucleotide repeats in ATM and MRE11 were found in nine and six lines, respectively, whereas mutations of mononucleotide repeats of RAD50 were found in only one line, and none were found in either NBS1 or ATR. Frequencies of ATM and MRE11 mutations were significantly higher in MSI-positive than MSI-negative lines. These mutations generated aberrant splicing in both genes. The intensity of the aberrant transcript of ATM (497del22) was stronger in five lines harboring mononucleotide mutations of 2 bp or more than in the lines without or with a 1-bp mutation. The intensity of the aberrant transcript of MRE11 (315del88) was stronger in four lines with mononucleotide mutations than in lines without. The expression levels of ATM and MRE11 transcripts in MSI-positive lines were significantly higher than those in MSI-negative lines. MSI-positive cell lines showed delay or abrogation of DSB repair. The present study suggests that impairment of the MMR system causes aberrant transcripts in the DSB repair genes ATM and MRE11. This might result in inactivation of the DSB repair system, thus inducing an acceleration of genome instability and accumulation of genetic damage. (Cancer Sci 2006; 97: 226,234) [source] Adhesion of Epstein,Barr virus-positive natural killer cell lines to cultured endothelial cells stimulated with inflammatory cytokinesCLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 3 2008H. Kanno Summary Chronic active Epstein,Barr virus (EBV) infection (CAEBV) is characterized by chronic recurrent infectious mononucleosis-like symptoms. Approximately one-fourth of CAEBV patients develop vascular lesions with infiltration of EBV-positive lymphoid cells. Furthermore, EBV-positive natural killer (NK)/T cell lymphomas often exhibit angiocentric or angiodestructive lesions. These suggest an affinity of EBV-positive NK/T cells to vascular components. In this study, we evaluated the expression of adhesion molecules and cytokines in EBV-positive NK lymphoma cell lines, SNK1 and SNK6, and examined the role of cytokines in the interaction between NK cell lines and endothelial cells. SNKs expressed intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) at much higher levels than those in EBV-negative T cell lines. SNKs produced the larger amount of tumour necrosis factor (TNF)-,, which caused increased expression of ICAM-1 and VCAM-1 in cultured human endothelial cells, than that from EBV-negative T cell lines. Furthermore, SNKs exhibited increased adhesion to cultured endothelial cells stimulated with TNF-, or interleukin (IL)-1,, and the pretreatment of cytokine-stimulated endothelial cells with anti-VCAM-1-antibodies reduced cell adhesion. These indicate that the up-regulated expression of VCAM-1 on cytokine-stimulated endothelial cells would be important for the adhesion of EBV-positive NK cells and might initiate the vascular lesions. [source] | |||||||||||||||||||||||||