Reciprocal leukemia-stroma VCAM-1/VLA-4-dependent activation 1 of NF-κB mediates chemoresistance

Bone marrow (BM) mesenchymal stromal cells (BM-MSC) upregulate their NF-κB signaling to protect leukemia cells from chemotherapy-induced apoptosis. To elucidate molecular mechanisms by which leukemia-stroma interactions within the BM microenvironment could confer chemoresistance to leukemia cells, we used genome-wide gene expression profiling (GEP) to examine human normal BM-MSC that had been co-cultured with the pre-B ALL REH cells and then separated by flow cytometry (FACS). GEP results for co-cultured cells of each type were compared to GEP results for cells of the corresponding type cultured alone, and taken through the same FACS purification procedure, to identify changes in gene expression profiles caused by co-culture.