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

The objective of this study was to examine whether CD45 mediates interleukin 6 (IL-6) signaling in human multiple myeloma (MM) cells. We chose U266 MM cells as a study model and isolated cells into CD45+ and CD45- subpopulations. CD45+ and CD45- U266 cells were cocultured with bone marrow stromal cells (BMSCs). IL-6-induced proliferation in CD45+ U266 cells was inhibited by vanadate, a potent protein tyrosine phosphatase inhibitor. However, IL-6-independent CD45- U266 cell growth was not affected by vanadate. CD45+ U266 cells, but not CD45- U266 cells, have the capability of cell adhesion concomitant with actin filament polymerization at the adherent cells. Adhesion of CD45+ U266 cells to BMSCs was impaired by vanadate. We clarified the signaling differences between CD45+ and CD45- U266 cells in response to IL-6. In CD45+ U266 cells, IL-6 increased tyrosine phosphorylation of gp130 and STAT3 and stimulated the level of Mcl-1 protein expression. An association between CD45 and the Src-family protein tyrosine kinase, Lyn, was maintained in the presence of IL-6; the formation of the CD45/Lyn complex was impaired by vanadate. Additionally, IL-6-induced Lyn kinase activity in CD45+ U266 cells was increased by the cross-linking of CD45, and this increase was due to the dephosphorylation of Tyr507 at Lyn. In conclusion, IL-6-dependent MM cells require CD45 to initiate IL-6 signaling and to maintain Lyn kinase activity, both of which are essential for cell proliferation and cell adhesion.
 ...
PMID:The protein tyrosine phosphatase CD45 is required for interleukin 6 signaling in U266 myeloma cells. 1497 81

Monoclonal antibodies (mAb) directed against lineage-specific B-cell antigens have provided clinical benefit for patients with hematologic malignancies, but to date no antibody-mediated immunotherapy is available for multiple myeloma. In the present study, we assessed the efficacy of a fully human anti-CD40 mAb CHIR-12.12 against human multiple myeloma cells. CHIR-12.12, generated in XenoMouse mice, binds to CD138-expressing multiple myeloma lines and freshly purified CD138-expressing cells from >80% multiple myeloma patients, as assessed by flow cytometry. Importantly, CHIR-12.12 abrogates CD40L-induced growth and survival of CD40-expressing patient multiple myeloma cells in the presence or absence of bone marrow stromal cells (BMSC), without altering constitutive multiple myeloma cell proliferation. Immunoblotting analysis specifically showed that PI3-K/AKT, nuclear factor-kappaB (NF-kappaB), and extracellular signal-regulated kinase activation induced by CD40L (5 mug/mL) was inhibited by CHIR-12.12 (5 mug/mL). Because CD40 activation induces multiple myeloma cell adhesion to both fibronectin and BMSCs, we next determined whether CHIR-12.12 inhibits this process. CHIR-12.12 decreased CD40L-induced multiple myeloma cell adhesion to fibronectin and BMSCs, whereas control human IgG1 did not. Adhesion of multiple myeloma cells to BMSCs induces interleukin-6 (IL-6) and vascular endothelial growth factor (VEGF) secretion, and treatment of multiple myeloma cells with CD40L further enhanced adhesion-induced cytokine secretion; conversely, CHIR-12.12 blocks CD40L-enhanced IL-6 and VEGF secretion in cocultures of multiple myeloma cells with BMSCs. Finally, CHIR-12.12 triggered lysis of multiple myeloma cells via antibody-dependent cellular cytotoxicity (ADCC) but did not induce ADCC against CD40-negative multiple myeloma cells, confirming specificity against CD40-expressing multiple myeloma cells. These results provide the preclinical rationale for clinical trials of CHIR-12.12 to improve patient outcome in multiple myeloma.
 ...
PMID:Human anti-CD40 antagonist antibody triggers significant antitumor activity against human multiple myeloma. 1599 68

Recent studies have underscored the role of B-cell-activating factor (BAFF), a member of the tumor necrosis factor superfamily, in promoting the survival of malignant B cells, including human multiple myeloma. We here characterized the functional significance of BAFF in the interaction between multiple myeloma and bone marrow stromal cells (BMSC) and further defined the molecular mechanisms regulating these processes. BAFF is detected on BMSCs derived from multiple myeloma patients as evidenced by flow cytometry. BAFF secretion is 3- to 10-fold higher in BMSCs than in multiple myeloma cells, and tumor cell adhesion to BMSCs augments BAFF secretion by 2- to 5-fold, confirmed by both ELISA and immunoblotting. Adhesion of MM1S and MCCAR multiple myeloma cell lines to KM104 BMSC line transfected with a luciferase reporter vector carrying the BAFF gene promoter (BAFF-LUC) significantly enhanced luciferase activity, suggesting that nuclear factor-kappaB (NF-kappaB) activation induced by multiple myeloma adhesion to BMSCs mediates BAFF up-regulation. Moreover, BAFF (0-100 ng/mL) increases adhesion of multiple myeloma lines to BMSCs in a dose-dependent manner; conversely, transmembrane activator and calcium modulator and cyclophylin ligand interactor-Ig or B-cell maturation antigen/Fc blocked BAFF stimulation. Using adenoviruses expressing dominant-negative and constitutively expressed AKT as well as NF-kappaB inhibitors, we further showed that BAFF-induced multiple myeloma cell adhesion is primarily mediated via activation of AKT and NF-kappaB signaling. Importantly, BAFF similarly increased adhesion of CD138-expressing patient multiple myeloma cells to BMSCs. These studies establish a role for BAFF in localization and survival of multiple myeloma cells in the bone marrow microenvironment and strongly support novel therapeutics, targeting the interaction between BAFF and its receptors in human multiple myeloma.
 ...
PMID:Role of B-cell-activating factor in adhesion and growth of human multiple myeloma cells in the bone marrow microenvironment. 1681 41

Adhesion of myeloma cells to bone marrow stromal cells is now considered to play a critical role in chemoresistance. However, little is known about the molecular mechanism governing cell adhesion-mediated drug resistance (CAM-DR) of myeloma cells. In this study, we focused our interests on the implication of the Wnt signal in CAM-DR. We first screened the expression of Wnt family in myeloma cell lines and found that Wnt3 was overexpressed in all the myeloma cells examined. KMS-5 and ARH77, which highly expressed Wnt3 protein, tightly adhered to human bone marrow stromal cells, and accumulation of beta-catenin and GTP-bounded RhoA was observed in these myeloma cell lines. Conversely, RPMI8226 and MM1S, which modestly expressed Wnt3 protein, rather weakly adhered to human bone marrow stromal. We then examined the relevance of Wnt3 expression to adhesive property to stromal cells and to CAM-DR of myeloma cells. KMS-5 and ARH-77 exhibited apparent CAM-DR against doxorubicin. This CAM-DR was significantly reduced by anti-integrin beta(1) antibody, anti-integrin alpha(6) antibody and a Wnt-receptor competitor, secreted Frizzled-related protein-1, and Rho kinase inhibitor Y27632, but not by the specific inhibitor of canonical signaling (Dickkopf-1), indicating that Wnt-mediated CAM-DR that is dependent on integrin alpha(6)/beta(1) (VLA-6)-mediated attachment to stromal cells is induced by the Wnt/RhoA/Rho kinase pathway signal. This CAM-DR was also significantly reduced by Wnt3 small interfering RNA transfer to KMS-5. These results indicate that Wnt3 contributes to VLA-6-mediated CAM-DR via the Wnt/RhoA/ROCK pathway of myeloma cells in an autocrine manner. Thus, the Wnt3 signaling pathway could be a promising molecular target to overcome CAM-DR of myeloma cells.
 ...
PMID:Wnt3/RhoA/ROCK signaling pathway is involved in adhesion-mediated drug resistance of multiple myeloma in an autocrine mechanism. 1757 6

Adhesion is a hallmark of haematological and solid cancer cells. All five classes of cell adhesion molecules (CAM) - integrins, cadherins, immunoglobulin-like CAMs, selectins and CD44s - are characteristically dysregulated in human cancer. Adhesion enables and promotes cancer-defining biological processes like growth, survival, migration, extravasation, homing, and metastasis. Furthermore, cell adhesion mediates drug resistance (CAM-DR) in multiple myeloma, malignant lymphoma, acute and chronic leukaemias, as well as in pancreatic cancer, neuroblastoma, small cell and non-small cell lung cancer, mesothelioma, colorectal carcinoma, and breast cancer. Cell adhesion protects from death by radiation, genotoxic chemotherapy, or targeted pathway inhibitors. Adhesion molecules are overexpressed on drug resistant cells (e.g. multiple myeloma or prostate cancer). Very recently, several cell adhesion mediated survival pathways have been elucidated, with key mediators being LFA-1, VLA-4, FAK, ILK, Src, PI3K, Akt, Ras, MEK, Erk, HMG-CoA reductase, Rho, Rho kinase, PKC, and NFkB. Because the surface and the intracellular targets are now known and because specific compounds are becoming increasingly available, first clinical trials regarding ANTI-ADHESION therapies are ongoing. However, in comparison to the comprehensive preclinical and clinical knowledge about CAMs, the number of drugs developed thusfar is quite low. ANTI-ADHESION strategies include targeting of surface antigens, inhibition of cell adhesion associated pathways, inhibition of CAM-DR, and targeted drug delivery. As ANTI-ADHESION is based on general characteristics of cancer cells independent of specific disease entities or treatment modalities, it may become a successful, low-toxic and broadly applicable concept in cancer treatment.
 ...
PMID:ANTI-ADHESION evolves to a promising therapeutic concept in oncology. 1839 55

Heat shock proteins (HSPs) are a super family of highly conserved molecular chaperone proteins, which are induced in response to stress. HSP70 has been demonstrated to inhibit apoptosis induced by a number of chemotherapeutic agents. Previous investigations have suggested the development of drug resistance in multiple myeloma (MM) cells after adhesion to stroma. This study used MM cell lines and primary plasma cells to determine if HSP70 had a role in development of chemo resistance. Adhesion of MM cells to either bone marrow stromal cells or fibronectin (FN) enhanced HSP70 expression. Inhibition of the HSP70 expression decreased 8226 cell adhesion to stroma or FN and induced more apoptosis in FN-adhered 8226 cells than in suspension cultures at 24 h. Further, HSP70 inhibitors enhanced melphalan-induced apoptosis and reversed melphalan-induced cell adhesion-mediated drug resistance (CAM-DR) phenotype. In addition, compared to parental cells, KNK-437, a heat shock factor inhibitor caused more apoptosis in melphalan-resistant 8226/LR5 cells and sensitized them to melphalan. Primary CD138 positive cells showed high expression of HSPA4 mRNA, and KNK-437 caused apoptosis in these cells. In conclusion, our data suggest inhibition of HSP70, reduced adhesion and caused apoptosis of both acquired and de novo drug resistant MM cells.
 ...
PMID:HSP70 inhibition reverses cell adhesion mediated and acquired drug resistance in multiple myeloma. 1850 84

Adhesion of multiple myeloma (MM) cells in the bone marrow (BM) is important for the growth and survival of the myeloma cells. Very late antigen-4 (VLA-4) is one of the main adhesion receptors that mediate MM cell binding to fibronectin (FN). In this study we have examined the effect of divalent cations on adhesion of MM cells to FN, and compared this type of adhesion with the adhesion induced by the cytokines HGF, IGF-1 and SDF-1alpha. Mn(2+) induced adhesion in all cell lines tested. Cytokine- and Mn(2+)-induced VLA-4-mediated adhesion were different in many respects, including binding specificity, adhesion kinetics and the activation state of VLA-4. To study a potential role of divalent cations in vivo, we measured the concentrations of divalent cations in BM plasma from 14 MM patients. We also found that Mn(2+)-mediated adhesion to FN activated the MAPK pathway, indicating that the interaction of MM-cells with FN mediated by Mn(2+) could play a critical role for growth and proliferation. In conclusion, this study shows a potential important role of divalent cations in MM cell biology and supports earlier studies pointing to activated VLA-4 as a key for homing of MM cells to the BM.
 ...
PMID:Mn2+ regulates myeloma cell adhesion differently than the proadhesive cytokines HGF, IGF-1, and SDF-1alpha. 1877 52

Multiple myeloma (MM) cell adhesion to stromal cells via very late antigen (VLA)-4 and vascular cell adhesion molecule (VCAM)-1 interaction causes enhanced secretion of osteoclastogenic activity by MM cells. We have reported that MM cell-derived macrophage inflammatory protein (MIP)-1alpha and MIP-1beta are responsible for most of the osteoclastogenic activity in MM. Thus, adhesion-mediated osteoclastogenesis may be caused by enhanced production of MIP-1 via VLA-4-VCAM-1 interaction. The present study was undertaken to clarify whether MM cell-derived MIP-1 plays a role in VLA-4-VCAM-1 adhesion-mediated osteoclastogenesis. Adhesion of MM cells to VCAM-1 upregulated MIP-1alpha and MIP-1beta production from MM cells and enhanced production of osteoclastogenic activity by MM cells. Blockade of MIP-1alpha and MIP-1beta actions not only abrogated elaboration of osteoclastogenic activity, but also suppressed spontaneous MM cell adhesion to VCAM-1. These results demonstrate that MM cell adhesion to VCAM-1 upregulates MIP-1 production by MM cells to cause enhancement of osteoclastogenesis. In addition, the results suggest that the increased production of MIP-1 further enhances MM cell binding to stromal cells via stimulation of VLA-4-VCAM-1 adhesion, forming a "vicious cycle" between MM cell adhesion to stromal cells and MIP-1 production via VLA-4-VCAM-1 interaction.
 ...
PMID:Vicious cycle between myeloma cell binding to bone marrow stromal cells via VLA-4-VCAM-1 adhesion and macrophage inflammatory protein-1alpha and MIP-1beta production. 1905 41

Nuclear factor-kappaB (NF-kappaB) has an important role in multiple myeloma (MM) cell pathogenesis in the context of the bone marrow (BM) microenvironment. In NF-kappaB signaling cascades, IkappaB kinase alpha (IKKalpha) and IKKbeta are key molecules that predominantly mediate noncanonical and canonical pathways, respectively. In this study, we examined the biologic sequelae of the inhibition of IKKalpha versus IKKbeta in MM cell lines. All MM cell lines have constitutive canonical NF-kappaB activity, and a subset of MM cell lines shows noncanonical NF-kappaB activity. Adhesion to BM stromal cells further activates both canonical and noncanonical NF-kappaB activity. IKKbeta inhibitor MLN120B blocks canonical pathway and growth of MM cell lines but does not inhibit the noncanonical NF-kappaB pathway. Although IKKalpha knockdown induces significant growth inhibition in the cell lines with both canonical and noncanonical pathways, it does not inhibit NF-kappaB activation. Importantly, IKKalpha down-regulation decreases expression of beta-catenin and aurora-A, which are known to mediate MM cell growth and survival. Finally, IKKbeta inhibitor enhances the growth inhibition triggered by IKKalpha down-regulation in MM cells with both canonical and noncanonical NF-kappaB activity. Combination therapy targeting these kinases therefore represents a promising treatment strategy in MM.
 ...
PMID:Biologic sequelae of I{kappa}B kinase (IKK) inhibition in multiple myeloma: therapeutic implications. 1927 Feb 64

Multiple myeloma remains an incurable disease; however, newer biologically based therapies aimed at various molecular-cellular targets are showing promise. Some of these drugs target critical pathways of the tumor cell and the bone marrow microenvironment. A brief review of the pathogenesis of multiple myeloma is presented. Genetic aberrations are hallmarks of the disease. Chromosome 14 translocations are responsible for cellular processes implicated in tumorigenesis. Adhesion to the extracellular matrix and bone marrow stromal cells augments drug resistance and inhibits apoptosis. Bortezomib, a proteasome inhibitor, acts on bone marrow constituents blocking many signaling cascades mediating multiple myeloma cell growth, survival, and drug resistance. Bortezomib and other cell-cycle targeted therapies offer hope in the fight against multiple myeloma.
 ...
PMID:Characteristics, pathogenesis, and novel treatments for multiple myeloma. 1979 22


<< Previous 1 2 3 4 Next >>