Fig. 1. 3D culture of endothelial cells expressing constitutively active PIK3CA isoforms recapitulates irregular and enlarged vessel phenotypes associated with VMs.
(A) Control cells and endothelial cells expressing PIK3CA-activating mutations cultured in 3D fibrin matrices and imaged at 0 and 168 hours after seeding. Scale bars, 1000 μm. (B and C) Representative confocal images of control and PIK3CAE542K vascular networks. Vascular networks were labeled with fibrin (magenta), 4′,6-diamidino-2-phenylindole (DAPI) (white), actin (green), and endothelial cell–specific CD31 staining (cyan). Vascular networks were fixed 3 days after seeding. Scale bars, 100 μm. (D) Quantification of images in (A). (n = 3 to 5 independent experiments; mean ± SD; one-way analysis of variance (ANOVA) with Tukey post test, *P ≤ 0.05; ***P ≤ 0.001; ****P ≤ 0.0001). ns, not significant.