TISSUE-SPECIFIC STEM CELLS Matrix Metalloproteinase 1 Is Necessary for the Migration

Human mesenchymal stem cells (MSCs) have increasingly been used as cellular vectors for the delivery of therapeutic genes to tumors. However, the precise mechanism of mobili-zation remains poorly defined. In this study, MSCs that expressed similar cell surface markers and exhibited multi-lineage differentiation potentials were isolated from various donors. Interestingly, different MSC isolates displayed dif-ferential migration ability toward human glioma cells. We hypothesized that distinct molecular signals may be involved in the varied tumor tropisms exhibited by different MSC isolates. To test this hypothesis, gene expression pro-files of tumor-trophic MSCs were compared with those of non–tumor-trophic MSCs. Among the various differentially regulated genes, matrix metalloproteinase one (MMP1