Plumbagin suppresses endothelial progenitor cell-related angiogenesis in vitro and in vivo

Plumbagin, a naturally occurring naphthoquinone component isolated from the root of Plumbago zeylanica, reduces angiogenesis in human umbilical vein endothelial cells; whether plumbagin also has anti-angiogenic activity in human endothelial progenitor cells (EPCs) has remained unclear. Importantly, the recruitment of bone marrow-derived EPCs promotes physiological and pathological neovascularization. In this study, plumbagin inhibited vascular endothelial growth factor (VEGF)-induced migration and tube formation of human EPCs, without cytotoxic effects. We also found that plumbagin inhibited angiogenesis via the phospholipase C (PLC), Akt, extracellular-signal-regulated kinase (ERK), nuclear factor (NF)-KB and hypoxia-inducible factor (HIF)-1 signaling pathways. In an EPC Matrigel plug assay, plumbagin significantly diminished microvessel formation and EPC-specific marker expression. Our report is the first to reveal that plumbagin reduces EPC-related angiogenesis both in vitro and in vivo. Further evaluations of plumbagin are warranted, to determine its antitumor activity and other angiogenesis-related disorders.