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)

Adhesion of hematopoietic progenitor cells to marrow-derived adherent cells has been noted for erythroid, myeloid, and lymphoid precursors. In this report, we have characterized very late antigen (VLA) integrin expression on normal CD34+ marrow progenitors, on leukemic cell lines, and on blasts from patients with acute myelogenous or monocytic leukemias. CD34+ progenitor cells expressed the integrin beta 1 chain (CD29), VLA-4 alpha (CD49d), and VLA-5 alpha (CD49e). The myeloid lines KG1 and KG1a also expressed CD49d and CD49e as did the Mo7e megakaryoblastic line. CD29, CD18, and CD11a were also present on each of these cell lines. Only the Mo7e line expressed the cytoadhesins GPIIbIIIa or GPIb. Binding of KG1a to marrow stroma was partially inhibited by antibodies to CD49d and its ligand, vascular cell adhesion molecule (VCAM-1). The majority of leukemic blasts studied expressed CD49d and CD49e as well. Blasts from patients with acute myelomonocytic leukemia consistently bound to stroma at levels greater than 20%, and adhesion to stroma could in some cases be partly inhibited by anti-CD49d. No role for glycosylphosphatidyl-inositol (GPI)-linked structures was demonstrated in these binding assays because the adhesion of leukemic blasts to stroma was not diminished after treatment with phosphatidylinositol-specific phospholipase C (PI-PLC). These studies indicate that CD34+ myeloid progenitors, myeloid leukemic cell lines, and leukemic blasts possess a similar array of VLA integrins. Their functional importance individually or in combination with other mediators of attachment in adhesion, transendothelial migration, and differentiation has yet to be fully elucidated.
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PMID:Expression of integrins and examination of their adhesive function in normal and leukemic hematopoietic cells. 767 62

Lymphocyte function-associated antigen 1/intercellular adhesion molecule 1 (LFA-1/ICAM-1)-and very late antigen 4/vascular cell adhesion molecule 1 (VLA-4/VCAM-1)-mediated adhesion of T lymphocytes to endothelial cells (EC) can be regulated by increased expression of ICAM-1 and VCAM-1 upon cytokine treatment of EC, or by activation of the integrin molecules LFA-1 and VLA-4 on T cells. Here, we provide evidence that preferential usage of LFA-1 over VLA-4 is yet another mechanism to control T cell adhesion. We observed that binding of activated T lymphocytes, as opposed to resting T cells, to EC is essentially mediated through LFA-1 and not through VLA-4. VLA-4-mediated adhesion of T cells to EC is only found when LFA-1 is not expressed or not functional, as observed for several T cell leukemia cell lines. These results suggest that LFA-1-mediated adhesion dominates and may downregulate VLA-4-mediated adhesion through an unidentified mechanism.
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PMID:Lymphocyte function-associated antigen 1 dominates very late antigen 4 in binding of activated T cells to endothelium. 767 12

We have utilized two well-characterized human leukemia/lymphoma (LL) cell lines, UTMB-460 and CEM, to determine the role of integrin very late antigen-alpha 4 beta 1 (VLA-4) and its ligand vascular cell adhesion molecule-1 (VCAM-1) in the adherence of the LL cells to marrow stromal cells (MSC). Both these LL cell lines express alpha and beta subunits of VLA-4. VCAM-1 is constitutively expressed by human MSC and its expression can be upregulated by interleukin-4 (IL-4) and recombinant human tissue necrosis factor-alpha (rTNF-alpha). IL-4 and rTNF-alpha stimulation of MSC is associated with a significant increase in the adherence of both UTMB-460 and CEM LL cells to the cytokine-stimulated MSC. Monoclonal antibodies directed against the alpha and beta subunits of VLA-4 and VCAM-1 significantly inhibit adherence of the LL cells to unstimulated and cytokine-treated MSC. The data reported indicate that VCAM-1 and integrin VLA-4 are obligatory adhesion proteins in the heterotypic adherence between human LL cells and MSC. The constitutive expression of VCAM-1 by MSC may be partially responsible for retention of leukemia cells in th bone marrow and metastasis of lymphomas to the bone marrow.
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PMID:Vascular cell adhesion molecule-1 and VLA-4 are obligatory adhesion proteins in the heterotypic adherence between human leukemia/lymphoma cells and marrow stromal cells. 768

We studied the adhesion properties of peripheral blood leukemic cells from 10 patients with adult T-cell leukemia (ATL) to endothelial cells to better understand the mechanism of leukemic cell infiltration. ATL cells expressed lymphocyte function-associated antigen-1 (LFA-1), but the expression of very late antigen-4 (VLA-4) and sialyl-Lewisx (SLex) was variable. They did not express sialyl-Lewisa (SLea). Cell adhesion assays, which were performed in nine patients, showed marked adhesion of ATL cells to interleukin [IL]-1-activated human umbilical vein endothelial cells (HUVEC). A monoclonal antibody (MoAb) against E-selectin consistently inhibited ATL cell adhesion, and an MoAb against vascular cell adhesion molecule-1 (VCAM-1) or an MoAb against VLA-4 sometimes diminished it. In contrast, an MoAb against LFA-1 had a minor effect on freshly isolated ATL cell adhesion to HUVEC. The percentage of SLex+ cells in the cell population adherent to IL-1-activated HUVEC was slightly higher than that in unseparated cells. These results, together with the detection of E-selectin expression on the endothelium at ATL skin lesions, indicate that E-selectin-mediated adhesion is the major pathway for the adherence of ATL cells to endothelial cells. In addition, the ligand for E-selectin on ATL cells appears to differ from that on neutrophils.
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PMID:E-selectin and vascular cell adhesion molecule-1 mediate adult T-cell leukemia cell adhesion to endothelial cells. 768 74

Adhesion between leukemic cells and the vascular endothelium has been suggested to play a role in the development of leukostasis in myelocytic leukemia. To define the role of adhesion molecules on the surface of endothelial cells in leukostasis, we used immunohistochemistry to study the expression of endothelial leukocyte adhesion molecule-1 (ELAM-1), vascular cell adhesion molecule-1 (VCAM-1), and intercellular adhesion molecule-1 (ICAM-1) in lung tissue of 4 patients with pulmonary leukostasis. Lung tissue of 2 patients with myelocytic leukemia without leukostasis and 4 patients with irrelevant nonpulmonary disease was used as a negative control. Positive control tissues included a lymph node with angioimmunoblastic lymphadenopathy and a hyperplastic tonsil. Weak positive staining for ELAM-1 was found in 1 patient in vessels, both with and without leukostasis. Expression of VCAM-1 and ICAM-1 in all patients tested was similar to that in the negative controls. The results of this study suggest that activation of endothelium, with increased expression of the endothelial adhesion molecules under study, is not a prerequisite for the development of pulmonary leukostasis in leukemia.
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PMID:Endothelial activation antigens in pulmonary leukostasis in leukemia. 823 71

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

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

The spread of leukemia extends from mobilization of leukemic blast cells from the bone marrow to extramedullary tissue infiltration. Migration of leukemic blasts resembles that of neutrophils and may be regulated by activated endothelial cells via endothelial adhesion molecules such as E-selectin, VCAM-1 and ICAM-1. Plasma levels of soluble adhesion molecules may therefore indicate interaction between leukemic blasts and endothelium, and may be related to leukemic cell mass or subtype of leukemia. In this study, plasma levels of soluble E-selectin, VCAM-1 and ICAM-1 were analyzed in 40 untreated patients with acute leukemia (35 ANLL, five ALL). Plasma concentrations of all three receptors were significantly elevated when compared to healthy controls (P = 0.006, P = 0.0001, and P = 0.0001, respectively) but demonstrated high interindividual variations among leukemic patients. sE-selectin but not sVCAM-1 and sICAM-1 levels correlated with peripheral leukocyte and blast cell counts. Increased levels of either sE-selctin or sVCAM-1 were present in 32 out 40 leukemic patients (80%). FAB subgroups differed in levels of sVCAM-1. The highest levels were measured in acute myelomonocytic and lymphoblastic leukemia, ie in leukemia subtypes with a high incidence of extramedullary blast cell infiltration.
Leukemia 1996 Apr
PMID:Levels of circulating endothelial adhesion molecules (sE-selectin and sVCAM-1) in adult patients with acute leukemia. 861 47

Pulmonary distress symptoms and thrombotic complications are side-effects of all-trans-retinoic acid (ATRA) therapy for remission induction in acute promyelocytic leukaemia (APL). The ATRA-induced increase of leukaemic cell adhesive molecules may be responsible. To explore this we used a functional assay to study the effect of ATRA treatment on the adhesion of blast cells to cultured human endothelial cells (EC), endothelial cell matrix (ECM), and interleukin 1beta-activated EC (IL1 + EC). NB4 cells, a maturation-inducible human promyelocytic leukaemia cell line, were treated with 1 microM ATRA or the vehicle (control), labelled with 51Cr and tested in the adhesion assay. ATRA increased NB4 adhesion to EC (P<0.01), ECM (P<0.001) and IL1 + EC (P=n.s.). An inhibition study with anti-EC adhesion receptors MoAbs indicated that anti-E-selectin, anti-VCAM-1 and anti-ICAM-1 effectively inhibited cell adhesion to IL1 + EC (18+/-7%, 45 +/-6.9% and 29+/-6% inhibition, respectively) and to unstimulated EC. Preincubation of ATRA-treated NB4 cells with MoAbs anti-VLA4 and anti-LFA1, the VCAM-1 and ICAM-1 counter-receptors respectively, resulted in a significant inhibition of adhesion. Cytofluorimetric analysis of the NB4 cell membrane molecules confirmed the increase under ATRA of VLA4, LFA1, MAC1 and ICAM-1. Therefore ATRA increases NB4 cell adhesion to the endothelium and the subendothelial matrix. These findings parallel the increment of NB4 surface adhesive molecules, among which VLA4 and LFA1 appear to play an important part. These mechanisms may contribute to the complications of ATRA therapy in APL.
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PMID:All-trans-retinoic acid increases adhesion to endothelium of the human promyelocytic leukaemia cell line NB4. 863 29

All trans-retinoic acid (ATRA) induces complete remission in acute-promyelocytic-leukemia (APL) patients. This study investigated the adhesive properties of APL cells for the endothelium and the extracellular matrix, their motility and the effect of ATRA on these functions. Blasts from 7 APL patients adhered to resting and IL-1-activated endothelium, to the same degree as normal PMN. Adhesion was partially mediated by ICAM-1 and, for IL-1-activated endothelium, by VCAM-1 and E-selectin. These cells showed less adhesiveness for the matrix than PMN, although they maintained the same substrate preference: they adhered to fibronectin and thrombospondin, but not to laminin and type-IV collagen. Exposure to ATRA in vitro (1 microM for 48 to 96 hr) increased the adhesiveness of APL cells; this effect was particularly evident in the case of sub-endothelial matrix and fibronectin. A similar increment in adhesiveness was observed when comparing cells from 2 patients before and after treatment with ATRA. APL cells migrated in response to fMLP and motility was increased by ATRA. In conclusion, APL cells were less adhesive to the matrix than PMN, but treatment with ATRA considerably enhanced their adhesive properties. This could be important in determining the efflux of leukemic cells from the bone marrow and their tissue infiltration during ATRA therapy.
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PMID:Effect of all trans-retinoic acid (ATRA) on the adhesive and motility properties of acute promyelocytic leukemia cells. 898 93


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