Chemotactic importance of cytokines/chemokine on hMSC invasion and the implication of MMPs. hMSCs were seeded in the upper compartment of Transwell cell invasion chambers. The lower compartment was filled with DMEM containing TGF-β (100 ng/mL), IL-1α (50 ng/mL), TNF-α (50 ng/mL), or SDF-1α (100 ng/mL) as chemoattractants. Control wells contained DMEM medium only (Con). Both upper and lower compartments were provided without (▪) and with Ro 206-0222 (10 μg/mL) to inhibit MMP-2, MMP-9, and MT1-MMP activity (⊡). After a 48-hour period of incubation the amount of migrated cells was quantified. Results are given in fold increase relative to spontaneous cell migration in control wells. All experiments were performed in triplicate. The mean values ± SDs of 1 of 2 separate experiments are shown. *P < .05, **P < .01, ***P < .001.