Fig. 4. miR-9 suppresses cell migration by inhibiting CXCR4. (a) The migratory cells (lower chamber) were separately harvested for the in vitro cell migration assay. In a migration assay using the Transwell system, SDF-1, which is a CXCR4 ligand, was placed in the bottom chamber of the well and 10⁵ cells were added to the upper chamber and incubated for 24 hours. Percentage migration was calculated as (number of migrated cells/input cell number) × 100. Average cell number and standard deviation were determined from quadruplicate experiments. (b) Migration of CB-CD34⁺ with either miR-9 or anti-miR-9 was analyzed in the bottom chamber. Data and standard deviation were calculated from quadruplicate experiments. Student’s t-test: **p<0.01 and ***p<0.001. (c) Migration of TF-1 with either miR-9 or anti-miR-9 was analyzed in the bottom chamber. Data and standard deviation were calculated from quadruplicate experiments. Student’s t-test: *p<0.05, **p<0.01 and ***p<0.001.