Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0001511 (Adhesion)
 5,955 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In multiple myeloma, malignant plasma cells are localized in marrow and rarely circulate in peripheral blood. To investigate the role of adhesion proteins in this process, we determined the expression and function of adhesion molecules on cell lines derived from patients with myeloma. The U266, ARH-77, IM-9, and HS-Sultan cell lines strongly expressed beta 1 and alpha 4 integrins (89% to 98% positive), confirming that VLA-4 is the principal integrin on these cell lines. The U266 and IM-9 cell lines also expressed alpha 3 integrin on 15% to 20% cells. In contrast, all lines lacked cell surface alpha 2, alpha 5, and alpha 6 integrin expression (< 5% positive). These cell lines adhered to fibronectin (20% to 40% specific binding), without significant binding to either collagen or laminin. Adhesion of these cell lines to fibronectin was partially blocked with either anti-beta 1 integrin monoclonal antibody (MoAb) (75% inhibition), anti-alpha 4 integrin MoAb (75% inhibition), or RGD peptide (50% inhibition), but was unaffected by anti-alpha v beta 3 or anti-alpha IIb beta 3 MoAbs. Moreover, the combination of anti-beta 1 plus RGD peptide or anti-alpha 4 plus RGD peptide inhibited binding to fibronectin by 80% and 95%, respectively. Finally, pretreatment and coculture of the IM-9 cell line with interleukin-6 (IL-6) resulted in a 52% decrease in specific binding to fibronectin (30% +/- 6% to 15% +/- 6%; P = .001), associated with a decrease in the number of cells expressing VLA-4 and a decrease in intensity of VLA-4 expression. These data suggest that myeloma cells adhere to fibronectin through VLA-4 as well as through RGD-dependent mechanisms, and that this binding can be downregulated by IL-6. Future studies of binding of both myeloma cell lines and freshly isolated tumor cells to extracellular matrix proteins and to marrow stroma may enhance our understanding of localization and trafficking of cells within the bone marrow microenvironment.
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PMID:Characterization of adhesion molecules on human myeloma cell lines. 142 1

Adhesion of multiple myeloma (MM) cells to bone marrow stromal cells (BMSCs) not only localizes MM cells in the marrow microenvironment, but also triggers interleukin-6 (IL-6) secretion by BMSCs and related MM cell proliferation. In the present study, we characterized the regulation of IL-6 gene expression in BMSCs during MM cell adhesion. Adhesion of ARH-77, HS-Sultan, IM-9, and U266 MM cell lines to BMSCs and BMSC lines (LP 101 and AA 101) triggered 5-through 15-fold and 2-through 4-fold increases in IL-6 secretion, respectively. IL-6 mRNA transcripts were undetectable by Northern blotting in IM-9 MM cells or LP 101 BMSCs cultured alone; however, adherence of IM-9 cells to LP 101 cells induced a transient increase in IL-6 transcripts at 6 hours, followed by peak IL-6 secretion at 24 hours. To confirm increased IL-6 transcription and characterize its regulation, LP101 BMSCs were transiently transfected with full length and deletion fragments of the IL-6 promoter linked to the chloramphenicol acetyltransferase (CAT) reporter gene. Transient transfection of LP101 BMSCs with plasmid containing an intact NF-kappa B site showed a 6.8 +/- 0.4-fold increase in CAT activity triggered by IM-9 MM cell adhesion (n = 3, P < .05). Transfection of LP 101 cells with plasmid containing a single base pair deletion from the NF-kapp B binding motif abolished the MM adhesion-induced increase in CAT activity, whereas transfection with plasmid containing three copies of synthetic NF-kappa B sequence resulted in an 8.1 +/- 0.7-fold increase in CAT activity related to MM adhesion (n = 3, P < .05). These data suggest that the NF-kappa B site is one of the essential regulatory elements for MM cell adhesion-induced IL-6 transcription in BMSCs. Electrophoretic mobility shift assays confirmed the involvement of NF-kappa B activation in regulating MM adhesion-induced IL-6 transcription in BMSCs. Further characterization of the upstream events in the signalling cascade regulating IL-6 may not only delineate mechanisms of IL-6 regulation during paracrine MM cell growth, but also provide new therapeutic strategies based on interruption of IL-6 mediated tumor cell growth.
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PMID:Multiple myeloma cell adhesion-induced interleukin-6 expression in bone marrow stromal cells involves activation of NF-kappa B. 856 36

Cytokine stimulation can activate NF-kappaB that triggers inducible expression of E-selectin, VCAM-1 (Vascular Cell Adhesion Molecule-1) and ICAM-1 (Intercellular Cell Adhesion Molecule-1) in endothelial cells. In the previous study, we have shown that B lymphocytes and plasma cells can express E-selectin by constitutive activation of NF-kappaB. Here we show that human B lymphocytes and ARH-77 plasma cells expressed VCAM-1 and ICAM-1 in a cytokine dispensable mechanism. NF-kappaB antagonists could inhibit their expressions in ARH-77 cells. The activities of NF-kappaB for VCAM-1 and ICAM-1 promoters prior to cytokine stimulation were detected in ARH-77 cells using electrophoretic mobility shift assays. Again, NF-kappaB antagonists could abrogate these promoter activities. Taken together, our results demonstrate that NF-kappaB activation is the underlying molecular mechanism for constitutive expression of E-selectin, VCAM-1, and ICAM-1 on human B lymphocytes and plasma cells.
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PMID:NF-kappaB activation for constitutive expression of VCAM-1 and ICAM-1 on B lymphocytes and plasma cells. 1173 24

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.
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PMID:Wnt3/RhoA/ROCK signaling pathway is involved in adhesion-mediated drug resistance of multiple myeloma in an autocrine mechanism. 1757 6