Inhibitors of basement membrane collagen synthesis prevent endothelial cell alignment in Matrigel in vitro and angiogenesis in vivo

BACKGROUND: The formation of a basement membrane is the last step in the development of a new blood vessel. Matrigel, a laminin-rich reconstituted basement membrane matrix induces the differentiation of endothelial cells into capillary-like structures. EXPERIMENTAL DESIGN: The effect of inhibitors of basement membrane collagen synthesis, tricyclodecan-9-yl xanthate (D609) and 8,9-dihydroxy-7-methyl-benzo[b] quinolizinium bromide (GPA 1734), was investigated on endothelial cell tube formation on Matrigel in vitro and in an angiogenesis assay in C57 black mice in vivo. RESULTS: D609 and GPA 1734 caused a dose-dependent decrease in tube formation in vitro with complete inhibition at 50 μg/ml for D609 and 15 μg/ml for GPA 1734. The inhibitory effect on capillary tube formation by both agents was reversible. Tube formation correlated well with collagenous protein biosynthesis. Parallel studies on endothelial cells cultured on plastic indicate that cell viability, proliferation, attachment, and morphology were not affected by the presence of these collagen inhibitors at doses that blocked tube formation and collagen biosynthesis. D609 and GPA 1734 also inhibited endothelial cell infiltration in response to SIK VAV in an in vivo angiogenesis model system. CONCLUSIONS: These results indicate that newly synthesised collagen is a prerequisite for expression of the endothelial cell phenotype for tube formation and that prevention of collagenous protein biosynthesis inhibits tube formation and angiogenesis in vivo.