Background/Aims: Stromal cell-derived factor-1 (SDF-1) has been shown to mediate a broad range of biological processes via CXCR4, once regarded as its only receptor. CXCR7 is a recently identified receptor for SDF-1. This study aimed to investigate whether the CXCR7/CXCR4/SDF-1 axis is involved in choroidal neovascularization (CNV) formation in an in vitro hypoxic model. Methods: CXCR7 siRNA and/or CXCR4 siRNA was transfected into a hypoxic model of the choroid-retinal endothelial RF/6A cell line. CCK-8 analysis, transwell migration analysis, annexin V-FITC and propidium iodide staining, and Matrigel tube formation analysis were performed to investigate the role of CXCR4 and CXCR7 in SDF-1-induced proliferation, migration, survival and tube formation of RF/6A cells. Results: CXCR4, but not CXCR7, mediates SDF-1-induced RF/6A cell migration and proliferation under hypoxic conditions, whereas CXCR7 was exclusively involved in RF/6A cell survival. In addition, CXCR7 and CXCR4 acted together to regulate RF/6A cell tube formation. Conclusion: The CXCR7/CXCR4/SDF-1 axis plays an important role in the formation of CNV, and may become a novel target for the treatment of CNV-associated diseases.

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