Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0079731 (B-cell lymphoma)
 16,671 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The CD53 antigen is a member of the tetraspan family of proteins with unknown function. Stimulation of rat IR938F B-cell lymphoma cells with monoclonal antibody MRC OX44 (anti-rat CD53) triggered a homotypic adhesion reaction which reached a maximum effect at 24 hr. This effect occurred at 37 degrees C but not at 4 degrees C. Adhesion was prevented by removal of divalent cations, Ca2+ and Mg2+, with EGTA and EDTA as chelating agents. The adhesion induced by MRC OX44 was inhibited by cycloheximide and actinomycin D, suggesting that de novo protein synthesis was required for this effect. The addition of mAb WT1 against rat LFA-1 (CD11a) antigen had no effect on adhesion, suggesting that the cell-cell interaction is not mediated by the expression of LFA-1 antigen. The intracellular signals required to induce adhesion were inhibited by two tyrosine kinase inhibitors, genistein and piceatannol. Wortmannin, a selective inhibitor of phosphoinositide 3-kinase activity, completely blocked adhesion. Two protein kinase C inhibitors, H7 and bisindolylmaleimide, inhibited the adhesion, suggesting that part of the signal is mediated by PKC. Electron microscopy of aggregated cells showed that the interaction is localized to short membrane regions, where contact areas of higher density in opposing zones from both cells were detected. We postulate that there is a common adhesion mechanism that is modulated by several tetraspan family members and associated proteins. This adhesion structure might represent a novel form of cell communication among lymphoid cells.
 ...
PMID:Ligation of CD53/OX44, a tetraspan antigen, induces homotypic adhesion mediated by specific cell-cell interactions. 922 4

BKS-2 is an immature B cell lymphoma that undergoes apoptotic cell death when signaled via its surface IgM receptor. To study the signaling components of surface IgM mediated apoptosis in B lymphoma cells, we generated mutants of BKS-2 that were resistant to anti-IgM induced apoptosis. One mutant cell line, 1.B5, did not undergo apoptotic cell death upon treatment with anti-IgM antibodies and also did not exhibit elevation of intracellular Ca2+ in response to cross-linking of surface IgM. This appeared to be due to a defect in protein tyrosine kinase (PTK) activity since fewer proteins were tyrosine phosphorylated in the mutant cells stimulated with anti-IgM when compared to wild type BKS-2. Subsequently, we showed that protein tyrosine kinases lyn and blk were inducibly tyrosine phosphorylated in the wild type BKS-2 but not in 1.B5 mutant cells in response to anti-IgM. Also the kinase activity of lyn was elevated in the wild type but not in mutant cells upon triggering through surface IgM. Furthermore, tyrosine phosphorylation of CD19, a known substrate of lyn, was inducible in anti-IgM stimulated BKS-2 cells but severely reduced in 1.B5 cells. In contrast, kinase activity of another src kinase, blk, was increased on anti-IgM stimulation in both wild type and mutant cells. Surprisingly, syk, a non-src protein tyrosine kinase important for surface IgM mediated signaling, was tyrosine phosphorylated in the lyn deficient mutant cells as well as in the wild type BKS-2 cells. Furthermore, anti-IgM induced increase in kinase activity of syk was similar in the mutant and wild type cells. Thus, in contrast to other studies that propose syk to be a downstream target of src family kinases, syk may act upstream of lyn in immature B cells. Consistent with a functional syk, its target, phospholipase gamma2 (PLC-gamma2) was normally tyrosine phosphorylated in mutant cells.
 ...
PMID:Activation of syk in an immature B cell line does not require lyn activity. 946 22

The 4-aminoquinolines, including chloroquine and hydroxychloroquine, have been successfully employed to treat patients with granuloma-forming disease-associated, vitamin D metabolite-mediated hypercalcemia. The calcium-lowering efficacy of these drugs has not been prospectively evaluated in patients with lymphoma and elevated 1,25-(OH)2D levels. Four such hypercalcemic patients with stage IV B-cell lymphoma were treated, two each, with either 400 mg daily oral hydroxychloroquine or a single course of prednisone-containing antitumor chemotherapy (CHOP). Antitumor therapy normalized the serum calcium and 1,25-(OH)2D concentration within 5 days. Over a 15-day period, hydroxychloroquine failed to reduce either the serum calcium or 1,25-(OH)2D level in lymphoma patients. In contrast, within 5 days 400 mg of hydroxychloroquine daily lowered elevated levels of calcium and 1,25-(OH)2D by 37% and 72%, respectively, in a hypercalcemic patient with sarcoidosis. These data suggest that regulation of the vitamin D-1-hydroxylase in lymphoma cells, the putative source of hormone in lymphoma patients, is refractory to the inhibitory actions of the aminoquinolines and that glucocorticoid-containing antitumor regimens are the antihypercalcemic therapies of choice in lymphoma patients with high 1,25-(OH)2D levels.
 ...
PMID:Inability of short-term, low-dose hydroxychloroquine to resolve vitamin D-mediated hypercalcemia in patients with B-cell lymphoma. 1002 56

The Src-homology domain 2 (SH2)-containing cytoplasmic tyrosine phosphatase, SHP-1 (SH2-containing protein tyrosine phosphatase-1), interacts with several B cell surface and intracellular signal transduction molecules through its SH2 domains. Mice with the motheaten and viable motheaten mutations are deficient in SHP-1 and lack most mature B cells. To define the role of SHP-1 in mature B cells, we expressed phosphatase-inactive SHP-1 (C453S) in a mature B cell lymphoma line. SHP-1 (C453S) retains the ability to bind to both substrates and appropriate tyrosine-phosphorylated proteins and therefore can compete with the endogenous wild-type enzyme. We found that B cells expressing SHP-1 (C453S) demonstrated enhanced and prolonged tyrosine phosphorylation of proteins with molecular masses of 110, 70, and 55-60 kDa after stimulation with anti-mouse IgG. The tyrosine kinase Syk was hyperphosphorylated and hyperactive in B cells expressing SHP-1 (C453S). SHP-1 and Syk were coimmunoprecipitated from wild-type K46 cells, K46 SHP-1 (C453S) cells, and splenic B cells, and SHP-1 dephosphorylated Syk. Cells expressing SHP-1 (C453S) showed increased Ca2+ mobilization, extracellular signal-regulated kinase activation, and homotypic adhesion after B cell Ag receptor engagement. Thus, SHP-1 regulates multiple early and late events in B lymphocyte activation.
 ...
PMID:Expression of dominant-negative src-homology domain 2-containing protein tyrosine phosphatase-1 results in increased Syk tyrosine kinase activity and B cell activation. 1007 16

The activation of phospholipase D in murine B cell lymphoma A20 cells treated with anti-Fas monoclonal antibody has been investigated. Fas cross-linking resulted in a both dose- and time-dependent increases in phospholipase D activity. There was a nearly maximum saturated rise in phospholipase D activity at the dose of 200 ng/ml anti-Fas monoclonal antibody showing a fourfold increase within 3 h. Fas activation also caused an approximately twofold increase of phosphatidylcholine-specific phospholipase C activity and 1,2-diacylglycerol release, which could be blocked by 30 min pretreatment with the phosphatidylcholine-specific phospholipase C inhibitor D609 (50 microgram/ml). Pretreatment of D609 also effectively inhibited the translocation of protein kinase C betaI and betaII from the cytosol to the membrane and the activation of phospholipase D induced by Fas cross-linking, suggesting that 1, 2-diacylglycerol released from the cellular phosphatidylcholine pool through phosphatidylcholine-specific phospholipase C plays a major role in protein kinase C/phospholipase D activation. Anti-Fas monoclonal antibody failed to elicit phosphoinositide-specific phospholipase C activation and any changes in the intracellular Ca2+ level in A20 cells, indicating that the phosphoinositide-mediated pathway is not involved in this Fas signaling. Therefore, these results suggest that Fas-mediated phospholipase D activation may be a consequence of primary stimulation of phosphatidylcholine-specific phospholipase C and that phospholipase D may play a role in Fas cross-linking signaling downstream from phosphatidylcholine-specific phospholipase C.
 ...
PMID:Fas-mediated activation of phospholipase D is coupled to the stimulation of phosphatidylcholine-specific phospholipase C in A20 cells. 1039 39

Sarcoidlike granulomas may occur in association with Hodgkin lymphoma and non-Hodgkin lymphoma. The granulomas may be concomitant and so extensive that they obscure the malignant process. In addition, a sarcoidosis-lymphoma syndrome has been described in which there appears to be a relationship between sarcoidosis and the development of a lymphoproliferative disorder. We report a case of a low-grade B-cell lymphoma with concomitant extensive sarcoidlike granulomas. The patient had no diagnostic clinical evidence of sarcoidosis, although she had an elevated serum calcium level and increased serum angiotensin converting enzyme activity. Increased serum calcium and serum angiotensin-converting enzyme activity have been associated with clinical sarcoidosis but have also occasionally been described in association with Hodgkin lymphoma and non-Hodgkin lymphoma without evidence of sarcoidosis. We describe our findings and illustrate the usefulness of immunoperoxidase immunophenotyping techniques in such a case.
 ...
PMID:Low-grade B-cell lymphoma and concomitant extensive sarcoidlike granulomas: a case report and review of the literature. 1062 50

The effect of lauryl gallate (antioxidant E-312) has been studied on the mouse B-cell lymphoma line Wehi 231. This compound is able to inhibit protein tyrosine kinases (PTKs) in whole cells and in crude extracts with a better efficiency than other well-known PTK inhibitors such as herbimycin or genistein. Initial events triggered upon the incubation of cells with lauryl gallate in phosphate-buffered saline (up to 1 h) include the inhibition of tyrosine phosphorylation, discharge of the mitochondrial transmembrane potential, and induction of mRNA for Bcl-2. Long-term cultures in complete medium supplemented with fetal calf serum (up to 24 h) in the presence of this compound exhibit clear apoptotic features such as increase in phosphatidylserine in the cell surface, decrease in the functionality of mitochondria, cytochrome c release to the cytosol, activation of caspases, hypodiploidy, and oligonucleosomal breakdown of DNA. Comparison between Wehi cells overexpressing Bcl-2 (Wehi-bcl-2) with Wehi-neo cells shows a delay in the manifestations of the apoptotic signs, indicating that Bcl-2 has a partial protective effect on the apoptosis induced by lauryl gallate. The proapoptotic effect of lauryl gallate is not dependent on DNA or protein synthesis, is not blocked by the chelation of calcium, and is not reverted by N-acetylcysteine.
 ...
PMID:Mechanistic aspects of the induction of apoptosis by lauryl gallate in the murine B-cell lymphoma line Wehi 231. 1118 55

The Kaposi's sarcoma-associated herpesvirus (KSHV) K1 gene encodes a polypeptide bearing an immunoreceptor tyrosine-based activation motif (ITAM) that is constitutively active for ITAM-based signal transduction. Although ectopic overexpression of K1 in cultured fibroblasts can lead to growth transformation, in vivo this gene is primarily expressed in lymphoid cells undergoing lytic infection. Here we have examined function of K1 in the setting of lytic replication, through the study of K1 mutants lacking functional ITAMs. Expression of such mutants in BJAB cells cotransfected with wild-type K1 results in dramatic inhibition of K1 signal transduction, as judged by impaired activation of Syk kinase and phospholipase C-gamma2 as well as by diminished expression of a luciferase reporter gene dependent upon K1-induced calcium and Ras signaling. Thus, the mutants behave as dominantly acting inhibitors of K1 function. To assess the role of K1 in lytic replication, we introduced these K1 mutants into BCBL-1 cells, a B-cell lymphoma line latently infected with KSHV, and induced lytic replication by ectopic expression of the KSHV ORF50 transactivator. Expression of lytic cycle genes was diminished up to 80% in the presence of a K1 dominant negative mutant. These inhibitory effects could be overridden by tetradecanoyl phorbol acetate treatment, indicating that inhibition was not due to irreversible cell injury and suggesting that other signaling events could bypass the block. We conclude that ITAM-dependent signaling by K1 is not absolutely required for lytic reactivation but functions to modestly augment lytic replication in B cells, the natural reservoir of KSHV.
 ...
PMID:Immunoreceptor tyrosine-based activation motif-dependent signaling by Kaposi's sarcoma-associated herpesvirus K1 protein: effects on lytic viral replication. 1139 May 90

Recent reports have demonstrated that EBV can be used as a target of specific CTL-based treatments in severe chronic EBV, immunoblastic B cell lymphoma and Hodgkin's disease (HD). Based upon the promising results form these in vivo studies, it has been suggested that an antigen-specific CTL-based immunotherapy may be of benefit in treating EBV-associated tumors such as HD and nasopharyngeal carcinoma (NPC) which express the potentially immunogenic antigens, LMP1 and LMP2a. Recent work form our group has demonstrated that LMP2a-specific CTLs may be generated in vitro using autologous antigen presenting cells which have been transfected with polyadenylated LMP2a RNA in the presence of a cationic lipid. In this study, we demonstrate that the presence of the lipid enhances dendritic cell (DC) transfection efficiency and appears to protect the intracellular LMP2a RNA from degradation by cellular RNAses. Significantly, these improvements resulted in the transfected DCs having a superior ability to stimulate autologous T cell proliferation. These LMP2a + DCs were used to stimulate LMP2a-specific effector cells which were predominantly a mixture of cytotoxic and helper CD4+ T cells. The molecular mechanisms whereby these CD4+ T cells lyzed their LMP2a-expressing targets was investigated and we show that, although expressing Fas ligand on their surface, LMP2a-specific CD4+ effector cells kill their targets using the Ca2+-dependent perforin/granzyme pathway which is the same mechanism used by CD8+ CTLs.
 ...
PMID:Antigen presenting cells transfected with LMP2a RNA induce CD4+ LMP2a-specific cytotoxic T lymphocytes which kill via a Fas-independent mechanism. 1240 Jun 9

A 75-yr-old male simultaneously having lymphoplasmacytic lymphoma (LPL) and diffuse large B-cell lymphoma (DLBCL) is presented. He had manifested with lumbago, high-grade fever, and confusion. Physical examination on admission showed disorientation and severe back pain. There were neither lymphadenopathy nor hepatosplenomegaly. Routine laboratory tests showed moderate pancytopenia, hypercalcemia (serum calcium, 15.9 mg/dL), IgM lambda-type monoclonal gammopathy (IgG, 405 mg/dL; IgA, 42 mg/dL; and IgM, 2023 mg/dL), and lambda-type Bence-Jones protein in the urine (0.8 g/d). Bone marrow biopsy showed the clusters of surface lambda-positive small-sized mature-appearing lymphoplasmacytoid cells. Bone survey and computed tomographic scan showed multiple osteolytic lesions and a tumor involving the third lumbar spine (L3). An open biopsy of the L3 tumor showed diffuse proliferation of CD20- and lambda-positive large cells. We thus diagnosed the patient as simultaneously having LPL and DLBCL. Although the combination chemotherapy was at least partially effective, he died of bacteremia and organ failure after three courses of chemotherapy. To clarify the clonal relatedness between LPL and DLBCL, we analyzed the sequences of the complementarity-determining region 3 in immunoglobulin heavy-chain genes. The data showed that LPL and DLBCL in the present patient originated from two independent clones.
 ...
PMID:Simultaneous development of lymphoplasmacytic lymphoma and diffuse large B-cell lymphoma--analyses of the clonal relatedness by sequencing CDR3 in immunoglobulin heavy chain genes. 1258 Nov 94


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>