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

Late-phase human T-cell lymphotropic virus I-associated adult T-cell leukemia cells express IL-2 receptors (IL-2R) but no longer produce IL-2. We have reported that the IL-2-independent adult T-cell leukemia line HuT-102 secretes a cytokine, provisionally designated IL-T, that stimulates T-cell proliferation and lymphokine-activated killer cell activity. Stimulation of proliferation of the cytokine-dependent human T-cell line Kit-225 mediated by HuT-102-conditioned medium or by 3200-fold-purified IL-T was not blocked by the addition of antibodies against IL-2 or IL-2R alpha subunit. However, IL-T-mediated stimulation of this human T-cell line was inhibited by addition of Mik-beta 1, an antibody that binds specifically to IL-2R beta subunit. In addition, the activation of large granular lymphocytes to lymphokine-activated killer cells mediated by IL-T-containing conditioned medium was not blocked by antibodies directed toward IL-2 or IL-2 alpha but was inhibited by an antibody to IL-2R beta, suggesting the requirement of this receptor subunit for IL-T action. This conclusion was confirmed using an IL-3-dependent murine myeloid precursor cell line, 32D, that expresses IL-2R alpha and IL-2R gamma, but not IL-2R beta. Neither IL-2 nor IL-T stimulated 32D cell proliferation. However, after transfection with the gene encoding human IL-2R beta, 32D beta cells proliferated on addition of either cytokine. The IL-T-mediated stimulation of 32D beta proliferation was inhibited by an anti-IL-2R beta antibody but not by an anti-IL-2 antibody. Thus, the IL-T-mediated stimulation of T-cell and lymphokine-activated killer cell activation requires the expression of the IL-2R beta subunit.
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PMID:The interleukin (IL) 2 receptor beta chain is shared by IL-2 and a cytokine, provisionally designated IL-T, that stimulates T-cell proliferation and the induction of lymphokine-activated killer cells. 819 61

Proteins containing vicinal dithiols were purified by affinity chromatography using Sepharose 4B linked to aminohexanoyl-4-aminophenylarsineoxide (As-Sepharose). The protein vicinal dithiols form stable dithioarsine derivatives with the arsine oxide moieties of the gel. The adsorbed proteins were eluted, at physiological pH, by buffers containing beta-mercaptoethanol or dithiothreitol. The dithiol proteins were identified by their specific labeling with N-iodoacetyl-3-[125I]-iodotyrosine. Cytoplasmic thiol proteins of L1210 murine leukemia lymphoblasts were separated into three classes by interaction with As-Sepharose. Proteins that did not bind to the gel consisted of monothiol proteins; proteins eluted by beta-mercaptoethanol include vicinal dithiol-containing proteins with low affinity for the arsine oxide. DL-Dithiothreitol (DTT) elutes a large group of vicinal dithiol-containing proteins with high affinity for the arsine groups. Gradient elution allowed characterization of the relative affinities of dithiol proteins for the As-Sepharose. A one-step purification of the L-triiodothyronine recombinant rat c-erb A beta 1 T3 receptor synthesized in yeast required pretreatment with DTT for binding to As-Sepharose and resulted in a 62-fold increase in specific activity. The procedure allows purification of proteins inhibited by phenylarsine oxide such as phosphotyrosine phosphatases, proteins that are subject to redox regulation, and dithiol proteins that are targets of oxidative stress.
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PMID:Arsenical-based affinity chromatography of vicinal dithiol-containing proteins: purification of L1210 leukemia cytoplasmic proteins and the recombinant rat c-erb A beta 1 T3 receptor. 821 73

We examined T-cell receptor gene rearrangement in skin lesions and peripheral blood from 6 patients with adult T-cell leukemia (ATL) using the Southern blot method and a c beta 1 probe. A rearrangement signal common to skin lesions of all 6 patients was observed. One patient (Case 4) exhibited another rearrangement signal in the skin lesion and an identical signal was detected in the peripheral blood. This is the first report describing a specific pattern of T-cell receptor gene rearrangement in ATL. The signal obtained is assumed to represent receptors of T cells involved in surveillance of HTLV-I infected T cells.
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PMID:T-cell receptor gene rearrangement in cells infiltrating skin eruptions specific to adult T-cell leukemia. 827 59

To elucidate control mechanisms of O-glycan biosynthesis in leukemia and to develop biosynthetic inhibitors we have characterized core 2 UDP-GlcNAc:Gal beta 1-3GalNAc-R(GlcNAc to GalNAc) beta 6-N-acetylglucosaminyltransferase (EC 2.4.1.102; core 2 beta 6-GlcNAc-T) and CMP-sialic acid: Gal beta 1-3GalNAc-R alpha 3-sialyltransferase (EC 2.4.99.4; alpha 3-SA-T), two enzymes that are significantly increased in patients with chronic myelogenous leukemia (CML) and acute myeloid leukemia (AML). We observed distinct tissue-specific kinetic differences for the core 2 beta 6-GlcNAc-T activity; core 2 beta 6-GlcNAc-T from mucin secreting tissue (named core 2 beta 6-GlcNAc-T M) is accompanied by activities that synthesize core 4 [GlcNAc beta 1-6(GlcNAc beta 1-3)GalNAc-R] and blood group I [GlcNAc beta 1-6(GlcNAc beta 1-3)Gal beta-R] branches; core 2 beta 6-GlcNAc-T in leukemic cells (named core 2 beta-GlcNAc-T L) is not accompanied by these two activities and has a more restricted specificity. Core 2 beta 6-GlcNAc-T M and L both have an absolute requirement for the 4- and 6-hydroxyls of N-acetylgalactosamine and the 6-hydroxyl of galactose of the Gal beta 1-3GalNAc alpha-benzyl substrate but the recognition of other substituents of the sugar rings varies, depending on the tissue. alpha 3-sialyltransferase from human placenta and from AML cells also showed distinct specificity differences, although the enzymes from both tissues have an absolute requirement for the 3-hydroxyl of the galactose residue of Gal beta 1-3GalNAc alpha-Bn. Gal beta 1-3(6-deoxy)GalNAc alpha-Bn and 3-deoxy-Gal beta 1-3GalNAc alpha-Bn competitively inhibited core 2 beta 6-GlcNAc-T and alpha 3-sialyltransferase activities, respectively.
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PMID:Processing O-glycan core 1, Gal beta 1-3GalNAc alpha-R. Specificities of core 2, UDP-GlcNAc: Gal beta 1-3 GalNAc-R(GlcNAc to GalNAc) beta 6-N-acetylglucosaminyltransferase and CMP-sialic acid: Gal beta 1-3GalNAc-R alpha 3-sialyltransferase. 829 5

Clonality in T-cell malignancy was investigated using T-cell receptor (TcR) V beta 1-20 family primers and polymerase chain reaction amplification (PCR) of cDNA prepared from tissue biopsies and blood involved with tumour. Secondary PCR amplification of the VDJ joints of primary PCR products was performed to distinguish clonal from polyclonal products, and clonal V beta gene products were confirmed by direct PCR sequencing in the majority of cases. In eight T-cell malignancies including T-cell acute lymphoblastic leukaemia (T-ALL) and T-cell chronic lymphocytic leukaemia (T-CLL) shown to be clonal by Southern blot analysis, one or two primary PCR products were identified and shown to be clonal. In five cases of peripheral T-cell lymphoma (PTCL) all V beta 1-20 families were identified after primary PCR amplification, and clonal products were identified in two cases after secondary amplification; TcR V beta clonal families could not be demonstrated in the remaining three cases. These data were in agreement with previous Southern blot analysis of these cases, and confirmed the presence of reactive T cells in PTCL as well as providing further evidence for the genotypic heterogeneity of this entity. In the remaining case, a blood lymphocytosis, primary PCR amplification produced predominant TcR V beta 6 and V beta 12 family products, of which the V beta 6 family proved clonal after secondary PCR amplification. There was no evidence for overrepresentation of TCR V beta families by the tumour populations in this study, furthermore the data confirm the involvement of reactive cells in T-cell malignancy and the genetic heterogeneity of PTCL.
Leukemia 1994 Feb
PMID:Polymerase chain reaction amplification analyses of clonality in T-cell malignancy including peripheral T-cell lymphoma. 830 53

We studied the effects of differentiation-inducers on the integrin profile and adhesive properties of K562 leukemia cells. The fibronectin (Fn) receptor integrin, alpha 5 beta 1, was the only integrin expressed in suspension cultured K562 cells. When the cells were exposed to 12-0-tetradecanoylphorbol-13-acetate (TPA) immunoreactivity for the beta 1 integrin subunit was slightly enhanced. TPA exposure also induced the appearance of the alpha 2, alpha 3, alpha v and beta 3 integrin subunits, but the platelet integrin subunit alpha IIb was not detected. On the other hand, hemin chloride-induced erythroid differentiation of K562 cells diminished the expression of the alpha 5 beta 1 integrin on the surface of the cells. Adhesion experiments with TPA-exposed K562 cells indicated that although the adherence to the extracellular matrix (ECM) proteins as a rule was low a few cells spread on these proteins. The present results specify the effects of differentiation inducers on the integrin profile of K562 cells and excludes the comprehension that TPA would induce expression of the platelet integrin alpha IIb on their surface. Our results also show, that an increased expression of a certain integrin does not necessarily lead to a comparable adhesion ability on its ligand in vitro.
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PMID:The effect of differentiation inducers on the integrin expression of K562 erythroleukemia cells. 831 51

To date, it is still unclear how the trafficking and retention of activated lymphocytes in periodontal lesions are regulated. In this study, we investigated the molecular basis for the adhesive interactions between lymphocytes and human gingival fibroblasts (HGF). Peripheral blood T lymphocytes (PBT) exhibited binding ability, but only when the calls were activated with phorbol 12-myristate 13-acetate (PMA). Among several human cell lines tested, PMA-stimulated Molt-4, a human T-cell leukaemia line, also displayed significant binding ability to HGF. In order to clarify the molecule(s) involved in this cell-cell interaction, a panel of monoclonal antibodies (mAb) was prepared to PMA-activated Molt-4 and one clone, 4-145, was selected on the basis of its ability to block the binding of PMA-activated Molt-4 to HGF. Moreover, 4-145 inhibited the binding of not only activated Molt-4 but also activated PBT and other cell types to HGF. Biochemical and flow cytometric analyses revealed that 4-145 probably recognizes the beta 1 chain of very late antigen (VLA) integrins. Blocking experiments using mAb specific for the alpha-chain of VLA integrins demonstrated the involvement of alpha 4 (VLA-4) and, to a lesser extent, alpha 5 (VLA-5) chains in the adhesive interactions between T cells and HGF. Despite the significant involvement of VLA integrins in the adhesive interaction between PBT and HGF, the binding of PBT to human dermal fibroblasts (HDF) was not abrogated by 4-145, suggesting that HGF and HDF differ in their requirement of VLA integrins for adhesion to activated PBT. Furthermore, the fact that vascular cell adhesion molecule-1 (VCAM-1), one of the ligands of VLA-4, was not detected on HGF by flow cytometry and anti-fibronectin (FN) Ab did not block the adhesive interaction to HGF suggests that not-yet-identified ligand(s) for VLA-4 might be present on HGF.
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PMID:Very late antigen integrins are involved in the adhesive interaction of lymphoid cells to human gingival fibroblasts. 840 71

In the present study, we have investigated the leukemic cells obtained from 16 patients with acute myeloid leukemia (AML) at diagnosis for the membrane expression of p55 (alpha) and p75 (beta) interleukin-2 receptor (IL-2R) chains using specific monoclonal antibodies (mAbs), as well as for the presence of their transcripts using Northern blot analysis. In addition, immunoprecipitation of the p75 membrane molecule with TU27 and Mik-beta 1 mAbs was carried out in selected cases. The p75 IL-2R beta transcripts were detected in all cases, whereas the membrane p75 molecule was demonstrable by flow cytometry in three cases. However, data from the immunoprecipitation analysis suggest that the lack of the p75 IL-2R detection by flow cytometry might be caused by the low density of molecules per cell rather than the fact that the specific mRNA is not translated into the p75 surface molecule. In addition, a consistent membrane positivity with an anti-p55/CD25 mAb, present on fresh uncultured blasts in 37.5% of the cases, became detectable after short-term culture in 75% of cases. In each individual case, a strict correlation was found between membrane CD25 reactivity and the expression of p55 mRNA. Taken together, our data suggest that the expression of both alpha (p55) and beta (p75) IL-2R molecules is a common feature of leukemic cells in AML, and provide new arguments for reassessing the possible role of IL-2 in leukemic growth.
Leukemia 1993 Mar
PMID:Alpha (p55) and beta (p75) chains of the interleukin-2 receptor are expressed by AML blasts. 844 47

Graft-vs.-leukemia (GVL) is postulated to be the principal mechanism responsible for continued remission after allogeneic bone marrow transplantation (BMT). The specific cytotoxic effectors mediating this effect are as yet undefined, but the major histocompatibility complex (MHC)-nonrestricted lysis of tumor cell lines by natural killer (NK) and lymphokine-activated killer (LAK) cells from recipients of allogeneic BMTs has been proposed as an in vitro correlate of GVL. In vitro culture or treatment in vivo with interleukin-2 (IL-2) is associated with enhanced NK cytotoxicity and lysis of NK-resistant targets (LAK cytotoxicity). NK, LAK, and cytotoxic T lymphocytes (CTL) have cytotoxic properties against autologous and allogeneic leukemic targets. These immune effector cells require receptor-ligand interaction for target recognition and adhesion via specific molecules such as integrins, a group of heterodimeric transmembrane glycoproteins. The integrins include the very late activation (VLA) subfamily, which all share the same beta 1 subunit but have distinct chains. VLA-6 (CDw49f) has been identified on NK cells and binds to laminin, a basement membrane protein found on malignant tumor cells but not normal cells. Monoclonal antibodies (mAbs) to laminin have been found to inhibit in vitro cytotoxicity of the tumor cell line K562, suggesting an important role for VLA-6 in this interaction. The specific aim of this study was to investigate the role of VLA-6 in the interactions of the tumor cell lines K562 and Daudi with peripheral blood lymphocytes (PBL) acting as effectors in cell-mediated cytotoxicity from normal volunteers, patients recovering from chemotherapy, and patients recovering from autologous or allogeneic BMT. In over 96% of assays, incubation of effector cells with anti-CDw49f mAbs led to detectable inhibition of NK and LAK cell-mediated cytotoxicity. More notably, the degree of anti-VLA6-induced suppression of LAK activity was significantly greater in the normal donors than in any of the patient groups, despite a significantly lower incidence of expression of VLA-6 on NK cells from controls than from patients. This implies a reduced role for this adhesion molecule in LAK activity following some form of in vivo stimulation. This hypothesis is supported by the observation that addition of exogenous IL-2 to the cultures ameliorated the effect of VLA-6 blockade, although the incidence and level of VLA-6 expression was unchanged by IL-2. In contrast, VLA-6 blocking led to a greater reduction in NK activity of BMT recipients than of normal donors, demonstrating that the VLA-6 adhesion pathway is important in this group of patients. These results indicate that the VLA-6-laminin interaction is important in normal NK-target interaction but may play a less significant role in the innate cytotoxic response post-BMT, perhaps reflecting subtle differences in the subsets of NK cells present in BMT recipients compared with normal donors.
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PMID:VLA-6 (CDw49f) is an important adhesion molecule in NK cell-mediated cytotoxicity following autologous or allogeneic bone marrow transplantation. 854 43

The ultrastructural changes in leukaemic cells on initial contact with, and during migration into, layers of bone marrow stroma in vitro were examined in a variety of types of acute leukaemia and leukaemic cell lines. Bone marrow fibroblasts (BMF) were grown on polycarbonate microporous membranes, and acute leukaemia cells added to cultures and allowed to adhere to BMF for variable periods of time before fixation. Acute lymphoblastic leukaemia (ALL) blasts showed rapid development of surface membrane microvilli on contact with BMF layers. ALL blasts, and the pre-B ALL cell line NALM-6, showed evidence of movement in to the BMF layer within 15-30 min, with intrusion of extended cytoplasic processes into gaps between BMF cytoplasm. ALL cells were frequently seen within the layers of fibroblasts after 30 min incubation, and had pronounced morphological changes, with pseudopodia and attenuated and elongated microvilli interdigitating with the surface of fibroblasts or with strands of extracellular matrix material. Changes were also noted in the surface membrane of BMF adjacent to ALL cells, with invagination of the cytoplasmic membrane and formation of micropits. In contrast to the migratory behaviour of pre-B ALL cells, migration was not observed with acute myeloid leukaemia cells or other leukaemic cell lines. These cells showed membrane activation, with variable degrees of microvillous formation, and in some cases insertion of pseudopodia into BMF layers, but migration was not observed. Ultrastructural immunogold labelling was carried out to determine the localization of leukaemic adhesion molecules and their ligands on BMF. This demonstrated that beta 1 integrins were largely localized to the contact surfaces of both ALL blasts and fibroblasts, with VCAM-1 expressed only on the surface of BMF. These observations confirm the specificity of migratory behaviour for pre-B leukaemic cells, and indicate that a complex pattern of surface and intracellular events mediate this process, including the expression of beta 1 integrins and VCAM-1 at the sites of insertion of leukaemic cells between fibroblast margins.
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PMID:Ultrastructural changes during adhesion and migration of pre-B lymphoid leukaemia cells within bone marrow stroma. 856 15


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