Anacardic acid (6-pentadecylsalicylic acid) inhibits tumor angiogenesis by targeting Src/FAK/Rho GTPases signaling pathway

Anacardic acid (6-pentadecylsalicylic acid), a natural inhibitor of histone acetyltransferase from Amphipterygium adstringens, has been shown to have anti-inflammatory, anticancer, antioxi-dative, and antimicrobial functions. However, whether this sal-icylic acid could block angiogenesis has not been elucidated to date. Here, we postulate that anacardic acid affects multiple steps of tumor angiogenesis to contribute to tumor inhibition. In this study, we found that vascular endothelial growth factor (VEGF)-induced cell proliferation, migration, and adhesion and capillary-like structure formation of primary cultured human umbilical vascular endothelial cells (HUVECs) could all be sig-nificantly suppressed by anacardic acid in vitro, without detect-able cellular toxicity. Furthermore, anacardic acid effectively inhibited vascular development in chick embryo chorioallantoi