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|Title:||The role of bone marrow mesenchymal stromal cells in the protection of B-cell chronic lymphocytic leukaemia from spontaneous and drug induced apoptosis|
|Presented at:||University of Leicester|
|Abstract:||An in vitro model to mimic in vivo conditions was developed using adherent BM Mesenchymal Stromal Cells (MSCs), isolated from the iliac crest of normal donors. These "fibroblast-like" MSCs provide a supporting layer for haemopoietic differentiation. They lack expression of haemopoietic differentiation antigens and lineage markers:- CD34, CD45, HLA-DR, CD31 and CD68 but express Vimentin, alphaSmooth Muscle Actin and Ab-1 (fibroblast marker). The model was used to determine if MSCs could protect B-CLL B cells from spontaneous apoptosis and prevent the effects of the therapeutic monoclonal antibodies Rituximab (CD20) and Campath-1H (CD52), the proteasomal inhibitor MG132 and BisIX, a protein kinase C inhibitor. Levels of apoptosis were determined by flow cytometry, using Annexin V-FITC/PI. MSCs abrogated spontaneous apoptosis of B-CLL B cells in direct contact with them, over 4 days (80-90% viability, n=30). Rituximab and Campath-1H induced apoptosis in the B-CLL B cells that could not be prevented by contact with MSCs (n=6). MG132 and BisIX caused substantial apoptosis in B-CLL B cells (0-15% viability) but MSCs could protect against lower concentrations (200nM) of both drugs (70-90% viability, n=6). MSCs' protection of B-CLL B cells from spontaneous apoptosis was through the upregulation of the expression of Mcl-1 and Xiap, but not Survivin. The cell-cell interactions include the beta1, beta2, beta3 and beta4 integrins but have variable effects on B-CLL cases when bound by blocking antibodies. Therefore MSCs can maintain B-CLL viability in vitro and influence chemotherapeutic strategies. The model provides a reliable method to evaluate drug cytotoxicity and Mcl-1 offers a novel therapeutic target.|
|Rights:||Copyright © the author. All rights reserved.|
|Appears in Collections:||Theses, Dept. of Cancer Studies & Molecular Medicine|
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