Breast Cancer Res Treat (2012) 134:943–955 DOI 10.1007/s10549-012-1977-9 P R E C L I N I C A L S T U D Y Ellagic acid, a phenolic compound, exerts anti-angiogenesis effects via VEGFR-2 signaling pathway in breast cancer Neng Wang • Zhi-Yu Wang • Sui-Lin Mo • Tjing Yung Loo • Dong-Mei Wang • Hai-Bin Luo • De-Po Yang • Yu-Ling Chen • Jian-Gang Shen • Jian-Ping Chen Received: 23 November 2011 / Accepted: 21 January 2012 / Published online: 21 February 2012 The Author(s) 2012. This article is published with open access at Springerlink.com Abstract Anti-angiogenesis targeting VEGFR-2 has been considered as an important strategy for cancer therapy. Ellagic acid is a naturally existing polyphenol widely found in fruits and vegetables. It was reported that ellagic acid interfered with some angiogenesis-dependent pathologies. Yet the mechanisms involved were not fully understood. Thus, we analyzed its anti-angiogenesis effects and mechanisms on human breast cancer utilizing in-vitro and in-vivo methodologies. The in-silico analysis was also carried out to further analyze the structure-based interac- tion between ellagic acid and VEGFR-2. We found that ellagic acid signiﬁcantly inhibited a series of VEGF- induced angiogenesis processes including proliferation, migration, and tube formation of endothelial cells. Besides, it directly inhibited VEGFR-2 tyrosine kinase activity and its downstream signaling pathways including MAPK and PI3K/Akt in endothelial cells. Ellagic acid also obviously inhibited neo-vessel formation in chick chorioallantoic membrane and sprouts formation of chicken aorta. Breast N. Wang Z.-Y. Wang T. Y. Loo J.-G. Shen J.-P. Chen (&) School of Chinese Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Estates Building, 10 Sassoon Road, Hong Kong, China e-mail: jpjpchen@yahoo.com S.-L. Mo The First Afﬁliated Hospital, Sun Yat-Sen University, Guangzhou 510080, China D.-M. Wang H.-B. Luo D.-P. Yang School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou 510080, China Y.-L. Chen Faculty of Pharmacy, The University of Sydney, Sydney, NSW 2006, Australia cancer xenografts study also revealed that ellagic acid signiﬁcantly inhibited MDA-MB-231 cancer growth and P-VEGFR2 expression. Molecular docking simulation indicated that ellagic acid could form hydrogen bonds and aromatic interactions within the ATP-binding region of the VEGFR-2 kinase unit. Taken together, ellagic acid could exert anti-angiogenesis effects via VEGFR-2 signaling pathway in breast cancer. Keywords Ellagic acid Anti-angiogenesis VEGF/VEGFR2 Molecular docking Breast cancer Introduction In recent decades, breast cancer has attracted global con- cern in recent decades. The global burden of breast cancer has engineered oncologists to develop novel strategies for breast cancer prevention and treatment [1, 2]. It has been recognized that angiogenesis is one of the essential hall- marks of cancer, typically breast cancer. To sustain growth, tumors require sufﬁcient nutrients, oxygen, and certain effective ways to evacuate waste. All the aforementioned needs can be addressed by angiogenesis, the process that consistently forms novel blood vessels into tumor masses from existing endothelium-lined vessels. Besides, exten- sive laboratory evidences supported that tumoral angio- genesis can be detected throughout the onset, growth, and metastasis in breast cancer [3, 4]. Thus, the anti-angio- genesis therapy has become one of the most important modalities in breast cancer treatment. Angiogenesis process is orchestrated by a balance between pro- and anti-angiogenic factors. During breast cancer progression, angiogenesis occurs when the activity of stimulators exceeds that of inhibitors. After vessel 123