Lenalidomide restrains motility and overangiogenic potential of bone marrow endothelial cells in patients with active multiple myeloma

Purpose:To determine the in vivo and in vitro antiangiogenic power of lenalidomide, a 9lead-compound9 of IMiDs immunomodulatory drugs in bone-marrow (BM) endothelial cells (ECs) of patients with multiple myeloma (MM) in active phase (MMECs). Experimental Design:The antiangiogenic effect in vivo was studied using the chorioallantoic membrane (CAM) assay. Functional studies in vitro (angiogenesis, "wound" healing and chemotaxis, cell viability, adhesion, and apoptosis) were performed in both primary MMECs and ECs of patients with monoclonal gammopathies of undetermined significance (MGECs) or healthy human umbilical vein endothelial cells (HUVECs). Real-time RT-PCR, Western blotting and differential proteomic analysis were used to correlate morphological and biological ECs features to the lenalidomide effects at gene and protein level. Results:Lenalidomide exerted a relevant antiangiogenic effect in vivo at 1.75 uM, a dose reached in interstitial fluids of patients daily treated with 25 mg. In vitro, lenalidomide inhibited angiogenesis and migration of MMECs, but not of MGECs or control HUVECs; and had no effect on MMECs viability, apoptosis, or fibronectin- and vitronectin-mediated adhesion. Lenalidomide-treated MMECs showed changes in VEGF/VEGFR2-signaling pathway and on several proteins controlling ECs motility, cytoskeleton remodeling, and energy metabolism pathways. Conclusions:This study provides information on the molecular mechanisms associated with the antimigratory and antiangiogenic effects of lenalidomide in primary MMECs, thus giving new avenues for effective endothelium-targeted therapies in MM.