Hindawi Publishing Corporation Evidence-Based Complementary and Alternative Medicine Volume 2013, Article ID 702869, 14 pages http://dx.doi.org/10.1155/2013/702869 Research Article Methanolic Extracts of Bitter Melon Inhibit Colon Cancer Stem Cells by Affecting Energy Homeostasis and Autophagy Deep Kwatra, 1 Dharmalingam Subramaniam, 1,2 Prabhu Ramamoorthy, 1,2 David Standing, 1,2 Elizabeth Moran, 1 Ravichandiran Velayutham, 3 Ashim Mitra, 4 Shahid Umar, 1,2 and Shrikant Anant 1,2 1 Department of Molecular and Integrative Physiology, University of Kansas Medical Center, 3901 Rainbow Boulevard MS 3040, Kansas City, KS 66160, USA 2 University of Kansas Cancer Center, University of Kansas Medical Center, 3901 Rainbow Boulevard MS 3040, Kansas City, KS 66160, USA 3 Department of Pharmacognosy, Vels University, Pallavaram, Chennai 600117, India 4 Department of Pharmaceutical Sciences, University of Missouri at Kansas City, Kansas City, MO 64108, USA Correspondence should be addressed to Shrikant Anant; sanant@kumc.edu Received 18 September 2012; Revised 21 January 2013; Accepted 29 January 2013 Academic Editor: Mani Vasudevan Copyright © 2013 Deep Kwatra et al. his is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Bitter melon fruit is recommended in ancient Indian and Chinese medicine for prevention/treatment of diabetes. However its efects on cancer progression are not well understood. Here, we have determined the eicacy of methanolic extracts of bitter melon on colon cancer stem and progenitor cells. Both, whole fruit (BMW) and skin (BMSk) extracts showed signiicant inhibition of cell proliferation and colony formation, with BMW showing greater eicacy. In addition, the cells were arrested at the S phase of cell cycle. Moreover, BMW induced the cleavage of LC3B but not caspase 3/7, suggesting that the cells were undergoing autophagy and not apoptosis. Further conirmation of autophagy was obtained when western blots showed reduced Bcl-2 and increased Beclin-1, Atg 7 and 12 upon BMW treatment. BMW reduced cellular ATP levels coupled with activation of AMP activated protein kinase; on the other hand, exogenous additions of ATP lead to revival of cell proliferation. Finally, BMW treatment results in a dose- dependent reduction in the number and size of colonospheres. he extracts also decreased the expression of DCLK1 and Lgr5, markers of quiescent, and activated stem cells. Taken together, these results suggest that the extracts of bitter melon can be an efective preventive/therapeutic agent for colon cancer. 1. Introduction Colorectal cancer is the second leading cause of cancer related deaths and the third most commonly occurring noncutaneous carcinoma in the United States of America [1]. Although early diagnosis oten leads to a complete cure, in most cases the polyps go undetected. In such cases, therapies such as surgical intervention, chemotherapy, and radiation are oten not suicient to tackle the disease, thus need- ing other prevention-related or nonconventional therapeutic strategies. Hence there is a need of better options for therapy and prevention of the disease. A number of studies have shown that diet can play a signiicant role in the development of colon cancer as a higher risk is associated with consumption of high-fat, low- iber diet and red meat [2, 3]. Use of certain foods and condiments (such as curcumin) in food may be responsible for lower prevalence of the disease in certain parts of India and central Asia [4, 5]. Bitter melon (Momordica charantia) is a tropical and subtropical vine, widely grown in Asia, Africa, and the Caribbean for its edible fruit. he fruit is recommended in ancient Indian and Chinese medicine for prevention/treatment of diabetes [6, 7], though all parts of the plant (fruit, seed, and leaves) have been shown to possess hypoglycemic properties [8]. Studies have shown that bitter melon extracts are well tolerated in both acute and chronic doses in animals [9–11]. Recent studies have demonstrated that aqueous extracts of bitter melon can inhibit the growth of