Protein (VEGF, IL-8, and MMP-9) production of THP-1 cells during differentiation. (A). THP-1 monocytic cells (n = 3) were differentiated for 3 days and were stimulated with LPS for 48 hours (hatched bars) or left unstimulated (open bars). Protein production of VEGF, IL-8 and MMP-9 was measured in cell supernatants by ELISA. In (B) the HIF-1α specific inhibitor YC-1 was added to the cultures (n = 3) and significant inhibition was seen for all proteins. Significance of inhibition was calculated compared to LPS stimulated sample (no inhibitor) with one-way ANOVA with Dunnett's post test: * p < 0.05, ** p < 0.01.