Pfn1-IN-2 is an inhibitor of Profilin1 (Pfn1) and has the activity to interfere with the interaction between Pfn1 and actin. Pfn1-IN-2 can significantly reduce the overall level of intracellular filamentous (F) actin. Pfn1-IN-2 also slows down the migration and proliferation of endothelial cells (EC). Pfn1-IN-2 can inhibit the angiogenic ability of endothelial cells both in vivo and in vitro.