Abrus agglutinin is a potent anti-proliferative and anti-angiogenic agent in human breast cancer Sujit K. Bhutia 1 , Birendra Behera 2 , Durgesh Nandini Das 1 , Subhadip Mukhopadhyay 1 , Niharika Sinha 1 , Prashanta Kumar Panda 1 , Prajna Paramita Naik 1 , Samir K. Patra 1 , Mahitosh Mandal 3 , Siddik Sarkar 4 , Mitchell E. Menezes 4 , Sarmistha Talukdar 4 , Tapas K. Maiti 2 , Swadesh K. Das 4,5 , Devanand Sarkar 4,5,6 and Paul B. Fisher 4,5,6 1 Department of Life Science, National Institute of Technology, Rourkela, India 2 Department of Biotechnology, Indian Institute of Technology, Kharagpur, India 3 School of Medical Science and Technology, Indian Institute of Technology, Kharagpur, India 4 Department of Human and Molecular Genetics, Virginia Commonwealth University, School of Medicine, Richmond, VA USA 5 VCU Institute of Molecular Medicine, Virginia Commonwealth University, School of Medicine, Richmond, VA USA 6 VCU Massey Cancer Center, Virginia Commonwealth University, School of Medicine, Richmond, VA USA Abrus agglutinin (AGG), a plant lectin isolated from the seeds of Abrus precatorius, has documented antitumor and immunosti- mulatory effects in murine models. To examine possible antitumor activity against breast cancer, we established human breast tumor xenografts in athymic nude mice and intraperitoneally administered AGG. AGG inhibited tumor growth and angiogenesis as confirmed by monitoring the expression of Ki-67 and CD-31, respectively. In addition, TUNEL positive cells increased in breast tumors treated with AGG suggesting that AGG mediates anti-tumorigenic activity through induction of apoptosis and inhibition of angiogenesis. On a molecular level, AGG caused extrinsic apoptosis through ROS generation that was AKT-dependent in breast cancer cells, without affecting primary mammary epithelial cells, suggesting potential cancer specificity of this natural compound. In addition, using HUVECs, AGG inhibited expression of the pro-angiogenic factor IGFBP-2 in an AKT-dependent manner, reducing angiogenic phenotypes both in vitro and in vivo. Overall, the present results establish that AGG promotes both apoptosis and anti-angiogenic activities in human breast tumor cells, which might be exploited for treatment of breast and other cancers. Cancer develops due to failures in mechanisms that normally control cell growth and proliferation. 1 Cancer is a multifaceted deregulated disease characterized by defined cellular behaviors, such as limitless replicative potential, autonomy with respect to growth signals, insensitivity towards growth-inhibitory signals, avoidance of cell death and sustained angiogenesis, together with evasion from immune attack. It follows that, to be success- ful, cancer therapies should focus on overriding these funda- mental characteristics of tumors. 1,2 The development of new tumor-specific drugs is greatly needed and there is significant interest in natural products that have clinical potential in the prevention and treatment of cancer. The plant lectins could be an alternative source of potential therapeutic molecules owing to their ease of availability and nontoxic properties. 3–5 Lectins are carbohydrate-binding proteins, which bind car- bohydrates reversibly and possess the ability to agglutinate cells or precipitate polysaccharides and glycoconjugates. 6,7 Lectins have been adapted for alternative tumor therapy in Europe. For decades, mistletoe lectin has been used as a complementary treatment for benign and malignant tumors. 8 Moreover, some plant lectins like concanavalin A, phytohemagglutinin, wheat germ agglutinin and others have shown potent antitumor activ- ity in preclinical studies thereby serving as potential antineo- plastic drugs for possible future cancer therapies. 3–5,9 Abrus agglutinin (AGG) isolated from the seeds of Abrus precatorius, an herbal medicinal plant in India, is a hetero- dimeric glycoprotein of 134-kDa molecular weight. It is Key words: Abrus, Akt, apoptosis, angiogenesis, IGFBP-2, ROS Additional Supporting Information may be found in the online version of this article. Grant sponsors: Research support was partly provided by the Rapid Grant for Young Investigators (RGYI), India [Number: BT/PR1/ 5090/GBD/27/309/2011], Department of Biotechnology; Science and Engineering Research Board (SERB), India [Number: SR/SO/BB- 0101/2012], Council of Scientific and Industrial Research (CSIR) [Number: 37(1608)/13/EMR-II] and Human Resource Development Group, Government of India. DOI: 10.1002/ijc.30055 History: Received 27 May 2014; Accepted 3 Dec 2014; Online 23 Feb 2016 Correspondence to: Dr. Sujit K. Bhutia, Assistant Professor, Department of Life Science, National Institute of Technology, Rourkela, India, E-mail: sujitb@nitrkl.ac.in or Dr. Paul B. Fisher, Professor and Chairman, Department of Human and Molecular Genetics, Director, VCU Institute of Molecular Medicine, VCU Massey Cancer Center, Virginia Commonwealth University, School of Medicine, 1101 East Marshall Street, Sanger Hall Building, Room11-015, Richmond, VA 23298-0033, Tel.:[804-828-9632], Fax: [804-827-1124], E-mail: paul.fisher@vcuhealth.org Cancer Therapy and Prevention Int. J. Cancer: 139, 457–466 (2016) V C 2016 UICC International Journal of Cancer IJC