Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0026764 (multiple myeloma)
 36,148 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Drug resistance remains a major obstacle to the treatment of many hematopoietic malignancies such as multiple myeloma. Although much research has been focused on acquired resistance phenotypes, we believe that de novo drug resistance mechanisms may be an important component in protecting cells from initial drug exposure. It is now realized that many of the biological processes associated with this disease, including cell survival, may come as a result of the direct interactions of malignant plasma cells with the bone marrow microenvironment. This review examines the role of cell adhesion to one bone marrow component, fibronectin (FN), and the impact it may have on response to cytotoxic drugs. We discuss the influence of the integrin VLA-4 (alpha4beta1) on cell adhesion mediated drug resistance (CAM-DR) as well as the effects of chronic drug exposure on integrin function. Data presented here demonstrates that drug selection can make a non-adherent cell line adherent to FN through inside-out integrin activation and consequently cause a decrease in sensitivity to drug. We also speculate on the possible mediators of this intrinsic mechanism of drug resistance which may, along with the integrins themselves, become promising therapeutic targets in cancer treatment.
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PMID:Integrin-mediated drug resistance in multiple myeloma. 1081 49

Cell migration requires a dynamic interaction between the cell, its substrate, and the cytoskeleton-associated motile apparatus. Integrin-associated protein (IAP)/CD47 is a 50-kd cell surface protein that is physically associated with beta3 integrins and that modulates the functions of beta3 integrins in various cells. However, in B-lymphocytes that express beta1 integrins but few beta3 integrins, the roles of IAP/CD47 remain to be determined. Cross-linking of IAP/CD47 by the immobilized anti-IAP/CD47 monoclonal antibody (mAb) B6H12, but not 2D3, produced signals to promote polarization with lamellipodia, a characteristic morphology during leukocyte migration, in pre-B and mature B-cell lines (BALL, Nalm6, ONHL-1, Daudi), but not in myeloma cell lines (RPMI8226, OPM-2). In the presence of the immobilized fibronectin (FN), soluble B6H12 could increase the rate of the polarization and activate migratory activity of BALL cells to FN in a transwell filter assay. Furthermore, the dominant-negative form of CDC42 completely blocked B6H12-induced morphologic and functional changes without inhibiting phorbol 12-myristate 13-acetate-induced spreading on FN in BALL cells, whereas the dominant-negative form of Rac1 inhibited all these changes. These findings demonstrate that in B-lymphocytes, IAP/CD47 may transduce the signals to activate the migratory activity, in which CDC42 may be specifically involved, and that IAP/CD47 shows synergistic effect with alpha4beta1 on B-cell migration. These findings would provide new insight into the role of IAP/CD47 on B-cell function.
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PMID:Integrin-associated protein/CD47 regulates motile activity in human B-cell lines through CDC42. 1089 56

The tumor cell environment may influence drug response through interactions with the extracellular matrix (ECM). We recently reported that adhesion of myeloma cells to fibronectin (FN) via beta1 integrins is associated with a cell adhesion mediated drug resistance (CAM-DR). Activation of beta1 integrins is known to influence both apoptosis and cell growth. We hypothesized that the FN mediated cytoprotection may be in part due to perturbations in cell cycle progression. In this report we demonstrate that adhesion of myeloma cells to FN results in a G1 arrest associated with increased p27kip1 protein levels and inhibition of cyclin A and E associated kinase activity. Disruption of cells from FN adhesion resulted in a rapid recruitment of cells into S phase, a decrease in p27kip1 levels, and reversion to a drug sensitive phenotype. Treatment of cells with p27Kip1 antisense oligonucleotides did not affect FN adhesion; however, p27Kip1 protein levels were reduced and cells became sensitive to cytotoxic drugs. These studies demonstrate that beta1 mediated adhesion of myeloma cells to FN regulates p27kip1 levels and that p27kip1 levels are causally related to CAM-DR. Disruption of beta1 integrin mediated FN adhesion may represent a potential target for the potentiation of drug induced apoptosis.
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PMID:Adhesion to fibronectin via beta1 integrins regulates p27kip1 levels and contributes to cell adhesion mediated drug resistance (CAM-DR). 1098 Jun 7

The chemokine stromal cell-derived factor-1alpha (SDF-1alpha) and its G-protein-linked receptor CXCR4 are involved in hematopoietic progenitor cell and lymphocyte migration. The integrin VLA-4 is a cell adhesion receptor for CS-1/fibronectin and VCAM-1 and constitutes one of the main adhesion receptors mediating myeloma cell adhesion to bone marrow (BM) stroma in multiple myeloma (MM). It is shown here that MM CD38(hi)CD45RA(-) BM cells and myeloma-derived cell lines expressed CXCR4 and displayed a moderate chemotactic response to SDF-1alpha. Because cell migration in response to SDF-1alpha might require a dynamic regulation of integrin function, it was investigated whether SDF-1alpha can modulate VLA-4 function on myeloma cells. SDF-1alpha rapidly and transiently up-regulated VLA-4-mediated myeloma cell adhesion to both CS-1/fibronectin and VCAM-1, which was inhibited by pertussis toxin and cytochalasin D, indicating the involvement of G(i) protein downstream signaling and an intact cytoskeleton. Modulation of VLA-4-dependent myeloma cell adhesion by SDF-1alpha could contribute to the trafficking and localization of these cells in the BM microenvironment.
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PMID:Chemokine stromal cell-derived factor-1alpha modulates VLA-4 integrin-mediated multiple myeloma cell adhesion to CS-1/fibronectin and VCAM-1. 1115 7

We have examined the in vitro anticancer activity of METVAN [bis(4,7-dimethyl-1,10 phenanthroline) sulfatooxovanadium(IV); VO(SO(4))(Me(2)-Phen)(2)] against acute lymphoblastic leukemia (ALL; NALM-6 and MOLT-3), acute myeloid leukemia (AML; HL-60), Hodgkin's disease (HS445), and multiple myeloma (ARH-77, U266BL, and HS-SULTAN) cell lines as well as primary leukemic cells from patients with ALL, AML, and chronic acute myeloid leukemia (CML). METVAN induced apoptosis in NALM-6, MOLT-3, and HL-60 cells in a concentration-dependent fashion with EC(50) values of 0.19 +/- 0.03 microM, 0.19 +/- 0.01 microM, and 1.1 +/- 0.2 microM, respectively. METVAN induced apoptosis at low micromolar concentrations in primary leukemic cells from patients with ALL, AML, and CML. METVAN inhibited the constitutive expression of matrix metalloproteinase (MMP)-9 protein and its gelatinolytic activity in HL-60 cells and MMP-2 as well as MMP-9 gelatinolytic activities in leukemic cells from ALL, AML, and CML patients. Furthermore, METVAN inhibited the leukemic cell adhesion to the extracellular matrix proteins laminin, type IV collagen, vitronectin, and fibronectin and the invasion through Matrigel matrix. Further preclinical development of METVAN may provide the basis for the development of more effective chemotherapy programs.
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PMID:Bis(4,7-dimethyl-1,10-phenanthroline) sulfatooxovanadium(I.V.) as a novel antileukemic agent with matrix metalloproteinase inhibitory activity. 1130 62

Bone marrow (BM) fibrosis may occur in myeloproliferative diseases, lymphoma, myelodysplastic syndrome, myeloma, and infectious diseases. In this study, the role of substance P (SP), a peptide with pleiotropic functions, was examined. Some of its functions-angiogenesis, fibroblast proliferation, and stimulation of BM progenitors-are amenable to inducing BM fibrosis. Indeed, a significant increase was found in SP-immunoreactivity (SP-IR) in the sera of patients with BM fibrosis (n = 44) compared with the sera of patients with hematologic disorders and no histologic evidence of fibrosis (n = 46) (140 +/-12 vs 18 +/-3; P <.01). Immunoprecipitation of sera SP indicated that this peptide exists in the form of a complex with other molecule(s). It was, therefore, hypothesized that SP might be complexed with NK-1, its natural receptor, or with a molecule homologous to NK-1. To address this, 3 cDNA libraries were screened that were constructed from pooled BM stroma or mononuclear cells with an NK-1 cDNA probe. A partial clone (clone 1) was retrieved that was 97% homologous to the ED-A region of fibronectin (FN). Furthermore, sequence analyses indicated that clone 1 shared significant homology with exon 5 of NK-1. Immunoprecipitation and Western blot analysis indicated co-migration of SP and FN in 27 of 31 patients with BM fibrosis. Computer-assisted molecular modeling suggested that similar secondary structural features between FN and NK-1 and the relative electrostatic charge might explain a complex formed between FN (negative) and SP (positive). This study suggests that SP may be implicated in the pathophysiology of myelofibrosis, though its role would have to be substantiated in future research. (Blood. 2001;97:3025-3031)
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PMID:Mimicry between neurokinin-1 and fibronectin may explain the transport and stability of increased substance P immunoreactivity in patients with bone marrow fibrosis. 1134 27

In multiple myeloma, the malignant plasma cells in the bone marrow attach to stromal elements using several adhesion receptors. The integrin VLA-4 plays a major role in mediating myeloma cell adhesion to the stroma, by interacting with its ligands VCAM-1 and fibronectin. VLA-4, as well as other integrins, can be expressed in different states of activation, which convey different levels of adhesion. Modulation of VLA-4 adhesive activity by external stimuli has been demonstrated for hematopoietic progenitor cells and lymphocytes, and can represent a potential mechanism contributing to the localization of myeloma cells in the bone marrow. In this review we have summarized data on the characterization of VLA-4-mediated myeloma cell adhesion, and we present potential mechanisms of modulation of VLA-4 activity. In addition, we also speculate on the signalling generated upon interaction of myeloma VLA-4 with its ligands on the survival of these cells in the bone marrow.
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PMID:VLA-4-dependent myeloma cell adhesion. 1137 37

Integrin-mediated cellular adhesion to extracellular matrix (ECM) components is an important determinant of chemotherapeutic response of human myeloma cells. Here, we demonstrate that when K562 chronic myelogenous leukemia (CML) cells are adhered to fibronectin (FN), they become resistant to apoptosis induced by the BCR/ABL inhibitors AG957 and STI-571, as well as DNA damaging agents and gamma-irradiation. This phenomenon, termed cell adhesion-mediated drug resistance (CAM-DR), was induced by adhesion through the alpha5beta1 (VLA-5) integrin. Phosphotyrosine analysis demonstrates that anti-apoptotic signaling through integrins in K562 cells is independent of the tyrosine kinases activated by BCR/ABL, with the possible exception of an unknown 80 kDa protein. Cytoprotection of FN-adhered CML cells indicates that tumor-ECM interactions may be critical for the emergence of drug-resistant tumor populations and treatment failure in this disease. Antagonists of beta1 integrin-mediated adhesion or corresponding signal transduction elements may sensitize CML cells to chemotherapy and prevent resistance to the novel BCR/ABL kinase inhibitors being used for the treatment of this disease.
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PMID:Cell adhesion-mediated drug resistance (CAM-DR) protects the K562 chronic myelogenous leukemia cell line from apoptosis induced by BCR/ABL inhibition, cytotoxic drugs, and gamma-irradiation. 1148 May 65

We previously showed that adhesion of myeloma cells to fibronectin (FN) by means of beta1 integrins causes resistance to certain cytotoxic drugs. The study described here found that adhesion of U937 human histiocytic lymphoma cells to FN provides a survival advantage with respect to damage induced by the topoisomerase (topo) II inhibitors mitoxantrone, doxorubicin, and etoposide. Apoptosis induced by a topo II inhibitor is thought to be initiated by DNA damage. The neutral comet assay was used to determine whether initial drug-induced DNA damage correlated with cellular-adhesion-mediated drug resistance. Cellular adhesion by means of beta1 integrins resulted in a 40% to 60% reduction in mitoxantrone- and etoposide-induced DNA double-strand breaks. When the mechanisms regulating the initial drug-induced DNA damage were examined, a beta1 integrin-mediated reduction in drug-induced DNA double-strand breaks was found to correlate with reduced topo II activity and decreased salt-extractable nuclear topo IIbeta protein levels. Confocal studies showed changes in the nuclear localization of topo IIbeta; however, alterations in the nuclear-to-cytoplasmic ratio of topo IIbeta in FN-adhered cells were not significantly different. Furthermore, after a high level of salt extraction of nuclear proteins, higher levels of topo IIbeta-associated DNA binding were observed in FN-adhered cells than in cells in suspension. Together, these data suggest that topo IIbeta is more tightly bound to the nucleus of FN-adhered cells. Thus, FN adhesion by means of beta1 integrins appears to protect U937 cells from initial drug-induced DNA damage by reducing topo II activity secondarily to alterations in the nuclear distribution of topo IIbeta.
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PMID:Reduction in drug-induced DNA double-strand breaks associated with beta1 integrin-mediated adhesion correlates with drug resistance in U937 cells. 1153 27

In multiple myeloma (MM), migration is necessary for the homing of tumor cells to bone marrow (BM), for expansion within the BM microenvironment, and for egress into the peripheral blood. In the present study we characterize the role of vascular endothelial growth factor (VEGF) and beta(1) integrin (CD29) in MM cell migration. We show that protein kinase C (PKC) alpha is translocated to the plasma membrane and activated by adhesion of MM cells to fibronectin and VEGF. We identify beta(1) integrin modulating VEGF-triggered MM cell migration on fibronectin. We show that transient enhancement of MM cell adhesion to fibronectin triggered by VEGF is dependent on the activity of both PKC and beta(1) integrin. Moreover, we demonstrate that PKC alpha is constitutively associated with beta(1) integrin. These data are consistent with PKC alpha-dependent exocytosis of activated beta(1) integrin to the plasma membrane, where its increased surface expression mediates binding to fibronectin; conversely, catalytically active PKC alpha-driven internalization of beta(1) integrin results in MM cell de-adhesion. We show that the regulatory subunit of phosphatidylinositol (PI) 3-kinase (p85) is constitutively associated with FMS-like tyrosine kinase-1 (Flt-1). VEGF stimulates activation of PI 3-kinase, and both MM cell adhesion and migration are PI 3-kinase-dependent. Moreover, both VEGF-induced PI 3-kinase activation and beta(1) integrin-mediated binding to fibronectin are required for the recruitment and activation of PKC alpha. Time-lapse phase contrast video microscopy (TLVM) studies confirm the importance of these signaling components in VEGF-triggered MM cell migration on fibronectin.
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PMID:Vascular endothelial growth factor-induced migration of multiple myeloma cells is associated with beta 1 integrin- and phosphatidylinositol 3-kinase-dependent PKC alpha activation. 1175 5


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