Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Activated lymphocytes release numerous products which are either synthesized de novo or in increased amounts; some of these products play a role in the regulation of the immune response and are designated as mediators of cellular immune reactions or lymphokines. The first lymphokine described was the macrophage migration inhibitory factor (MIF) which has been studied most extensively with regard to its chemical and biological properties. Using sensitive radiolabelling techniques and an antiserum against highly purified fractions of MIF we were able to identify several products of activated guinea pig lymphocytes with different molecular weights of 15.000, 30.000, 45.000, 60.000 which all had an isoelectric point of 5.2 and were all inhibitory to macrophage migration. It is suggested, that these molecules are oligomers of a common subunit of molecular weight 15.000. It was further shown, that molecules of the same physical-chemical and serological characteristics are produced by activated B-cells, L2C leukemia cells and growing fibroblasts, thus further substantiating earlier reports on the production of MIF by lymphoid and non-lymphoid cells. The described molecules were also shown not to contain determinants of the major histocompatibility complex and to be distinct from lymphotoxin, another lymphocyte activation product. It is concluded, that MIF is not a single molecule but rather a system of structurally related molecules. Their interaction with macrophages and possible relationships to macrophage activating factor is discussed.
 ...
PMID:The biochemistry and in vitro activity of soluble factors of activated lymphocytes. 39 92

Recombinant human tumor necrosis factor-alpha (TNF-alpha) was found to stimulate the growth of CMK, a human megakaryoblastic leukemia cell line. This stimulatory effect of TNF-alpha was blocked by anti-TNF-alpha antibody, but antibodies to recombinant human interleukin 3, granulocyte-macrophage colony-stimulating factor and interleukin 6 (all growth factors for CMK cells) did not reduce the stimulatory effect of TNF-alpha. Scatchard analysis showed that CMK cells expressed TNF-alpha receptors on the cell surface. The growth of CMK cells was also stimulated by lymphotoxin, which shares the same receptor as TNF-alpha. These results suggest that TNF-alpha stimulated the growth of CMK cells directly via its specific receptor.
 ...
PMID:Stimulatory effect of tumor necrosis factor-alpha on the growth of CMK, a human megakaryoblastic leukemia cell line. 131 36

Hypercalcemia in hematological malignancy is frequently encountered in lymphoid malignancies such as adult T-cell leukemia (ATL) and multiple myeloma and is difficult to manage. As a causative agent of hypercalcemia in ATL, tumor necrosis factor-beta (TNF-beta), previously known as lymphotoxin, has been carefully studied and reviewed here. Bone resorption studies showed the presence of activity in culture supernatants of HTLV-I infected cells. Enzyme linked immunosorbent assays (ELISA) for TNF-beta detected elevated TNF-beta in the sera of ATL patients with hypercalcemia. Immunostaining by monoclonal anti-TNF-beta antibody demonstrated the presence of TNF-beta in both HTLV-I infected cell lines and freshly isolated ATL cells. Furthermore biological TNF-beta activity assay including inhibition of anti-TNF-beta antibody confirmed the conventional documentation of TNF-beta activity in the sera and culture supernatants of HTLV-I infected cell lines. These studies showed that the TNF-beta secreted from ATL cells might be one of the factors contributing to the hypercalcemia in patients with ATL functioning as an osteoclast activating factor (OAF).
 ...
PMID:Tumor necrosis factor-beta and hypercalcemia. 149 42

Thuja polysaccharide g fraction (TPSg) was shown to be an inducer of the CD4+ fraction of the human peripheral blood T-cell subset (1,2). Furthermore, it could be demonstrated that TPSg is a potent inhibitor of the expression of HIV-1-specific antigens and of the HIV-1-specific reverse transcriptase (3). This report deals with the cytokine pattern induced by TPSg in human peripheral blood lymphocyte (PBL) and purified monocyte/macrophage cultures. In addition, a further characterization of the CD4+ T-cell fraction stimulated by TPSg was performed by FACS analysis. TPSg is induces IL-1 beta, IL-2, IL-3, IL-6, gamma-IFN, G-CSF, GM-CSF, and TNF-beta production in PBL cultures; and IL-1 beta and IL-6 in monocyte/macrophage cultures. Enzyme-linked immunosorbent assays (ELISAs) demonstrated that no IL-4 was produced by PBL cultures under TPSg influence.
Leukemia 1992
PMID:Mitogenic activity of high molecular polysaccharide fractions isolated from the cuppressaceae Thuja occidentalis L. enhanced cytokine-production by thyapolysaccharide, g-fraction (TPSg). 160 22

In this study we demonstrate that tumor necrosis factors (TNF alpha and TNF beta) are potent modulators of the in vitro proliferation of human AML cells. Blast cells from 11 cases of acute myeloblastic leukemia (AML) were incubated with recombinant TNF alpha or TNF beta in serum-free 3H-TdR uptake and colony culture systems in the presence or absence of recombinant interleukin-3 (IL-3), granulocyte macrophage colony-stimulating factor (GM-CSF), G-CSF, or M-CSF. Depending on the supplemented CSF, TNF could upregulate or suppress AML blast proliferation. Enhancement of AML growth by TNF was observed in the presence of IL-3 (in 9 of 11 cases in 3H-TdR assay; 6 of 9 cases in colony assay) and GM-CSF (in 8 of 11 cases in 3H-TdR assay; 4 of 9 cases in colony assay). In certain cases in which IL-3 or GM-CSF alone was unable to induce proliferative responses of AML cells, the simultaneous addition of TNF elicited colony growth and DNA synthesis suggesting a synergistic action between TNF and IL-3 or GM-CSF. In contrast, TNF suppressed G-CSF-induced growth (9 of 10 cases in 3H-TdR assay; 5 of 6 cases in colony assay). TNF could also stimulate DNA synthesis (in 2 of 11 cases) or colony formation (in 2 of 9 cases) in AML cultures without the addition of other growth factors. Experiments with neutralizing antibodies and specific radioimmunoassays for individual CSFs showed that the synergistic and antagonistic effects of TNF on AML growth could not be attributed to a release of one of these CSFs by the AML cells. The opposing consequence of exposure of AML blasts to TNF are of interest in view of our understanding of the pathophysiology of AML growth and the in vivo application of recombinant cytokines in AML patients.
Leukemia 1990 Jan
PMID:Modulation of colony stimulating factor-(CSF) dependent growth of acute myeloid leukemia by tumor necrosis factor. 168 38

We have previously shown that maturing neoplastic cells from patients with stable phase chronic myelogenous leukemia (SP CML) constitutively produce granulocyte colony-stimulating factor (G-CSF) and are also receptive for this molecule. G-CSF functions as an endogenous growth factor in SP CML, and thus is responsible for divisions in maturing leukemic cells leading to an expansion of the compartment of mature cells. In the investigations to be reported below, the effects of various hematopoietic inhibitor molecules on the expression of the G-CSF gene by SP CML bone marrow cells enriched for promyelocytes/myelocytes were examined at the mRNA and protein level. We show that exposure of SP CML bone marrow promyelocytes/myelocytes to recombinant human (rh) interferon (IFN)-gamma but not to rh IFN-alpha, rh tumor necrosis factor (TNF)-alpha, and rh lymphotoxin (LT) leads to downregulation of G-CSF expression and interruption of the G-CSF-mediated endogenous growth stimulation. The action of G-CSF takes place at the posttranscriptional level and involves an acceleration of decay of steady-state levels of G-CSF transcripts in the malignant cell population.
Leukemia 1990 Nov
PMID:Gamma-interferon interrupts growth stimulation in chronic myelogenous leukemia established by endogenous granulocyte colony-stimulating factor. 170 Feb 39

Lymphotoxin (LT; also known as tumor necrosis factor-beta) is a pleiotropic cytokine whose expression is tightly regulated in most cells and is repressed prior to activation signals. In some early B cells and Abelson murine leukemia virus-transformed pre-B-cell lines, LT mRNA is constitutively expressed. To examine the molecular regulation of the LT gene in a constitutively expressing cell line, we studied the Abelson murine leukemia virus-transformed lines PD and PD31. As demonstrated by primer extension analysis, constitutively expressed pre-B-cell-derived and inducibly expressed T-cell-derived LT mRNA were initiated at the same cap sites and predominant cap site utilization was conserved. Furthermore, we delineated an upstream activating sequence that was an important functional component of lymphotoxin transcriptional activation in PD and PD31 cells. The upstream activating sequence was localized to an essentially homopolymeric A + T-rich region (LT-612/-580), which was bound specifically by recombinant human high-mobility group I protein (HMG-I) and a PD/PD31 nuclear extract HMG-I (HMG-I-like) protein. The nuclear extract-derived HMG-I-like protein was recognized by anti-HMG-I antibody and bound to LT DNA to effect an electrophoretic mobility shift identical to that of bound recombinant human HMG-I. These findings implicate HMG-I in the regulation of constitutive lymphotoxin gene expression in PD and PD31 cells. HMG-I and HMG-I-like proteins could facilitate the formation of active initiation complexes by altering chromatin structure and/or by creating recognition sites for other activator DNA-binding proteins, some of which may be unique to or uniquely modified in these constitutive LT mRNA producers.
 ...
PMID:A poly(dA-dT) upstream activating sequence binds high-mobility group I protein and contributes to lymphotoxin (tumor necrosis factor-beta) gene regulation. 173 52

The human T-cell leukemia virus type I tax1 gene product is responsible for the increased expression of several cytokine and cellular genes that contain NF-kappa B regulatory sequences. Our laboratory has previously demonstrated that purified, extracellular Tax1 protein induced the nuclear accumulation of NF-kappa B binding activity in lymphoid cells. Since HTLV-I infection causes increased levels of lymphotoxin tumor necrosis factor-beta [TNF-beta] and immunoglobulin secretion, we have studied the interaction of NF-kappa B proteins from Tax1-stimulated cells with the TNF-beta and immunoglobulin kappa (Ig kappa) light chain genes. Tax1 induction of NF-kappa B occurred in the presence of cycloheximide, and Tax1 stimulation did not result in increased levels of NF-kappa B or c-rel RNA. These results indicate that new synthesis of NF-kappa B proteins was not required for induction of NF-kappa B-binding activity. With use of the Ig kappa NF-kappa B-binding site as a probe, two distinct NF-kappa B gel shift complexes were induced by the Tax1 protein. A slower-migrating complex, C1, was inhibited by the addition of purified I kappa B. In contrast, the faster-migrating C2 complex was not inhibited by I kappa B, but C2 was increased by detergent treatment of cytoplasmic extracts, suggesting that its binding activity was also regulated by an inhibitor. The Tax1-stimulated proteins that interacted with the NF-kappa B-binding sites in the Ig kappa and TNF-beta promoters were distinct. A 75-kDa protein preferentially associated with the Ig kappa NF-kappa B-binding site. In contrast, a 59-kDa protein associated with the TNF-beta NF-kappa B-binding site. Tax1 stimulation led to increased levels of TNF-beta and Ig kappa mRNA, as measured by reverse transcription and polymerase chain reaction analysis. These results represent the first experimental evidence that extracellular Tax1 can regulate the expression of endogenous cellular genes.
 ...
PMID:Extracellular Tax1 protein stimulates tumor necrosis factor-beta and immunoglobulin kappa light chain expression in lymphoid cells. 173 91

In order to investigate the possible mechanisms for the effect of alpha-interferon (alpha-IFN) in hairy cell leukaemia (HCL), blood cells from 4 cases were treated in vitro with alpha-IFN, tumour necrosis factor (TNF) and interleukin 2 (IL-2). Changes in the antigen expression, immunoglobulin (Ig) secretion and the production of TNF and lymphotoxin (LT) were investigated. TNF induced expression of CD4 and CD71, increased the intensity of HLA-DR, CD25, CD11c and CD13 expression and decreased both the intensity and frequency of sIg and cIg positivity. alpha-IFN decreased CD25 expression, the tartrate-resistant acid phosphatase activity (TRAP), reduced the TNF-induced CD4 and CD71 expression and antagonized the TNF effect on the Ig expression. Spontaneous TNF or LT production could not be detected in culture supernatants. However, TNF was found to induce LT production, an effect which alpha-IFN antagonized and IL-2 augmented. The reduction of CD25, TNF-induced CD71 and TRAP caused by alpha-IFN seems to represent a deactivation of the activated state of hairy cells (HCs). The failure of alpha-IFN to induce Ig secretion or CD38 expression in HCs speaks against a differentiation induction effect. The LT secretion induced by TNF suggests that other cytokines than TNF might be involved in the proliferation of HCs and that alpha-IFN by blocking the production of LT and perhaps other cytokines causes a growth arrest in HCs.
 ...
PMID:Effect of alpha-IFN on cytokine-induced antigen expression and secretion of TNF, LT and IgM in HCL. 192 51

Human T-cell leukemia virus type I (HTLV-I)-infected T-cell lines constitutively produce high levels of biologically active lymphotoxin (LT; tumor necrosis factor-beta) protein and LT mRNA. To understand the regulation of LT transcription by HTLV-I, we analyzed the ability of a series of deletions of the LT promoter to drive the chloramphenicol acetyltransferase (CAT) reporter gene in HTLV-I-positive MT-2 cells. The smallest LT promoter fragment (-140 to +77) that was able to drive CAT activity contained a site that was similar to the immunoglobulin kappa-chain NF-kappa B-binding site. Since the HTLV-I tax gene activates the nuclear form of NF-kappa B, this finding suggested a possible means of HTLV-I activation of LT production. We found that the LT kappa B-like site specifically formed a complex with NF-kappa B-containing nuclear extract from MT-2, C81-66-45, and other activated T cells. Mutation of the LT kappa B site in the context of the LT promoter (-293 to +77) (mutant M1) reduced the ability of the promoter to drive the CAT gene in HTLV-I-infected and noninfected human T-cell lines. These data suggest a general role for NF-kappa B activation in the induction of LT gene transcription. Activation of LT in HTLV-I-infected cells may explain the pathology associated with HTLV-I infection, including the hypercalcemia that is prevalent in adult T-cell leukemia.
 ...
PMID:Lymphotoxin activation by human T-cell leukemia virus type I-infected cell lines: role for NF-kappa B. 197 20


1 2 3 4 5 6 7 Next >>