Medulloblastoma cells (Daoy and D283 cells) were treated with mock (PBS Control), 50 MOI of Ad-SV or Ad-MMP-2 si for 24 h, and conditioned medium and cells were collected. (A) Top panel: Total RNA was extracted and semi-quantitative RT-PCR was performed for MMP-2; GAPDH was served as a control for RNA quality. Middle panel: MMP-2 levels were determined in the total cell lysates by western blot analysis using anti-MMP-2 antibody. GAPDH served as a loading control. Bottom panel: MMP-2 gelatinolytic activity was determined in the conditioned medium by gelatin zymography. Band intensities were quantified by densitometric analysis using ImageJ software (National Institutes of Health). The levels of MMP-2 mRNA, protein and gelatinolytic activity were normalized to levels in mock-transfected cells. Columns: mean of triplicate experiments; bars: SD; *p<0.05, significant difference from mock transfected control cells. (B) hUCBSCs migration towards tumor cell conditioned medium from medulloblastoma cells infected with Ad-MMP-2 si was studied in a transwell migration assay. Conditioned medium collected from mock, Ad-SV and Ad-MMP-2 si-infected tumor cells were designated as mock-CM, Ad-SV-CM and Ad-MMP-2 si-CM, respectively. The cells that had migrated to the lower side of the membrane were photographed under a light microscope at 20× magnification. Percentages of migrated cells were quantified by counting five fields in each condition. Results are representative of three independent experiments. Columns, mean of three experiments; bars, SD.