Fig. 6

Analysis of capillary tube formation and angiogenic sprouting of human endothelial cells in vitro. a Capillary tube formation of bortezomib (5 nM) and Aplidin™ and derivatives (10 nM) -treated HUVECs was analyzed in triplicate over a time window of 6 h (n = 3, mean ± SEM of three different donors) in direct comparison to respective controls (0.1 % DMSO, bortezomib, Aplidin™). Untreated cells indicate 100 % capillaries/mm² in matrigel. PM01215 and PM02781 significantly inhibited tube formation of HUVECs. The means of one treatment group are compared to untreated control. The level of significance for the analysis was set at p < 0.05. b Angiogenic sprouting of human endothelial cell spheroids in collagen type I/methylcellulose gel was analyzed after stimulation with 50 ng/mL human VEGF₁₆₅. (n = 3, mean ± SEM of three different donors). DMSO-treated (0.1 %) cells with VEGF stimulation correspond to 100 % cumulative sprout length. All tested drugs significantly inhibited VEGF-induced sprouting at concentrations of 1 to 10 nM. The means of one treatment group were compared to the DMSO control. Stars indicate p values < 0.05