Expression of superoxide dismutase-1 (SOD-1) and effects on secretion of vascular endothelial growth factor (VEGF) from multicellular structures and cells monolayers. (A) Expression of SOD-1 of cells cultured in 3D and 2D cell models. SOD-1 was maintained at high levels in cancer cells cultured as 3D multicellular structures compared with 2D cell monolayers. (B) Secreted VEGF in the media was collected and examined by ELISA. The (■) dark and (grey square symbol) grey bars represent 3D cell cultures and cell monolayers respectively. (*) P < 0.05, compared to control multicellular structures. (#) P < 0.05, compared to control cell monolayers. Data are expressed as the mean ± SEM.