FIG. 3.

Angiogenic factor secretion. (a) Effect of culture dimensionality (two-dimensional monolayer culture vs. 3D alginate culture) on VEGF and IL-8 secretion by OSCC-3 cells in response to hypoxia and ambient O₂ as measured by ELISA of the conditioned medium and normalization to DNA content. (b) Effect of 3D cell–extracellular matrix interactions on VEGF and IL-8 secretion by OSCC-3 cells in response to hypoxia and ambient O₂. To prevent and enable 3D integrin engagement, tumor cells were cultured within nonmodified or RGD-modified alginate disks, respectively. The conditioned medium was analyzed as described above. (c) Effect of 3D cell–extracellular matrix interactions on VEGF and IL-8 secretion by U87 cells in response to hypoxia and ambient O₂. All 3D medium samples were analyzed after 3 days of culture, whereas two-dimensional medium samples were measured after 2 days to prevent formation of 3D cell aggregates. (*p < 0.05, **p < 0.01, and ***p < 0.001).