Effect of MMP/TIMP knock-downs on hMSC invasion. hMSCs carrying knock-downs for the expression of MMP-2, MT1-MMP (MT1), TIMP-1, and TIMP-2 were assessed for their ability to traverse human ECM. The hMSCs were applied in the Transwell invasion assay 24 hours after their transfection and incubated for 48 hours. Thereafter, cells that had migrated to the lower chamber were counted. Control cells transfected with non–target-directed siRNA were set as 100%. Data are presented as mean ± SD of 1 triplicate experiment representative of 3 independent measurements. ***P < .001, **P < .01, *P < .05.