Three-dimensional in vitro assay of endothelial cell invasion and capillary tube morphogenesis

In vitro assays with endothelial cells (EC) cultured on three-dimensional gel recapitulate several aspects of vascular morphogenesis and pathological angiogenesis. The two most used in vitro assays of vascular mor- phogenesis are the tube formation on extracellular matrix gel and the sprouting from EC spheroids. Tube formation assay measures the ability of EC, plated on gel derived from reconstituted basement membrane, to form capillary-like structures. Sprouting assay is based on spheroids of EC, embedded in collagen gel and stimulated with angiogenic factors, which originate a complex network of capillary-like structures invading the gel. Both these assays can be exploited for antiangiogenic drug screening and gene function analysis during vascular morphogenesis.