Robo1: A Potential Role in Ocular Angiogenesis

Purpose: Robo1, a member of the roundabout (Robo) family, serves as neuronal guidance receptors and has been reported to mediate tumor angiogenesis. In this study, we investigated the function of Robo1 and its possible role in retinal angiogenesis in vitro and in vivo. Methods: Expression of Robo1 in relation to retinal neovascularization was studied in an animal model of retinopathy of prematurity (ROP). siRNA technology was used to knockdown Robo1 expression to study its effects on monkey choroidal retinal endothelial cells (RF/6A) in vitro. Cell proliferation, migration, spreading, cycling, and apoptosis were assessed with the methyl thiaz olyl tetrazolium (MTT), Boyden chamber, immunohistochemistry, and flow cytometry assay. Tube formation by RF/6A on Matrigel was also analyzed. Results: Robo1 expression was elevated in the ROP murine eyes (P<0.01). Knockdown of Robo1 expression inhibited cell proliferation and migration. Tube formation by RF/6A was also disturbed. Conclusions: Our results show that Robo1 inhibits choroidal and retinal angiogenesis in vitro. Further studies are ongoing to evaluate Robo1 as a potential target for the treatment of choroidal or retinal angiogenesis.