Comparison of bone-marrow mesenchymal stromal cells from multiple myeloma patients and healthy donors

It is now well established that bone marrow (BM) constitutes a microenvironment required for differentiation. Bone marrow mesenchymal stromal cells (BM-MSCs) strongly support MM cell growth, by producing a high level of Interleukin-6 (IL-6), a major MM cell growth factor. BM-MSCs also support osteoclastogenesis and angiogenesis. Previous studies have suggested that the direct (VLA-4, VCAM-1, CD44, VLA-5, LFA-1, syndecan-1,…) and indirect interactions (soluble factors) between MM plasma cells and BM-MSCs result in constitutive abnormalities in BM-MSCs. In particular, MM BM-MSCs express less CD106 and fibronectin and more DKK1, IL-1β and TNF-α as compared with normal BM-MSCs. In order to gain a global view of the differences between BM-MSCs from MM patients and healthy donors, we used gene expression profiling to identify genes associated to the transformation of MM BM-MSCs. BM-MSCs were isolated from 3 healthy donors and 4 untreated multiple myeloma patients. Total RNA from BM-MSCs was exctracted and hybridyzed on Affymetrix GeneChip® Human Genome U133 Plus 2.0 Array. Amplification, hybridization and scanning were done according to standard Affymetrix protocols (www.affymetrix.com). CEL files were normalized with RMA method.