Received: 6 November 2017 | Revised: 26 January 2018 | Accepted: 12 February 2018 DOI: 10.1002/mc.22791 RESEARCH ARTICLE Abrus agglutinin stimulates BMP-2-dependent differentiation through autophagic degradation of β-catenin in colon cancer stem cells Prashanta K. Panda 1 | Prajna P. Naik 1 | Prakash P. Praharaj 1 | Biswa R. Meher 2 | Piyush K. Gupta 3 | Rama S. Verma 3 | Tapas K. Maiti 4 | Muthu K. Shanmugam 5 | Arunachalam Chinnathambi 6 | Sulaiman A. Alharbi 6 | Gautam Sethi 5,7 | Rajesh Agarwal 8 | Sujit K. Bhutia 1 1 Department of Life Science, National Institute of Technology, Rourkela, India 2 Department of Botany, Berhampur University, Berhampur, India 3 Bhupat and Jyoti Mehta School of Biosciences, Department of Biotechnology, Indian Institute of Technology Madras, Chennai, India 4 Department of Biotechnology, Indian Institute of Technology, Kharagpur, India 5 Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 6 Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, Kingdom of Saudi Arabia 7 School of Biomedical Sciences, Curtin Health Innovation Research Institute, Curtin University, Perth, Western Australia, Australia 8 Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Denver, Aurora, Colorado Correspondence Dr. Sujit Kumar Bhutia, Department of Life Science, National Institute of Technology Rourkela, Rourkela 769008, Odisha, India. Emails: sujitb@nitrkl.ac.in, bhutiask@gmail.com Funding information Department of Biotechnology, Ministry of Science and Technology, Grant number: BT/ PR7791/BRB/10/1187/2013; Board of Research in Nuclear Sciences, Grant number: 37(1)/14/38/2016-BRNS/37276; International Scientific Partnership Program ISPP at King Saud University, Grant number: ISPP# 0091; Science and Engineering Research Board, Grant number: EMR/2016/001246; National Cancer Institute, Grant number: CA195708 Eradicating cancer stem cells (CSCs) in colorectal cancer (CRC) through differentiation therapy is a promising approach for cancer treatment. Our retrospective tumor-specimen analysis elucidated alteration in the expression of bone morphogenetic protein 2 (BMP-2) and β-catenin during the colon cancer progression, indicating that their possible intervention through “forced differentiation” in colon cancer remission. We reveal that Abrus agglutinin (AGG) induces the colon CSCs differentiation, and enhances sensitivity to the anticancer therapeutics. The low dose AGG (max. dose = 100 ng/mL) decreased the expression of stemness-associated molecules such as CD44 and β-catenin in the HT-29 cell derived colonospheres. Further, AGG augmented colonosphere differentiation, as demonstrated by the enhanced CK20/CK7 expression ratio and induced alkaline phosphatase activity. Interestingly, the AGG-induced expression of BMP-2 and the AGG-induced differentiation were demonstrated to be critically dependent on BMP-2 in the colonospheres. Similarly, autophagy-induction by AGG was associated with colono- sphere differentiation and the gene silencing of BMP-2 led to the reduced accumulation of LC3-II, suggesting that AGG-induced autophagy is dependent on BMP-2. Furthermore, hVps34 binds strongly to BMP-2, indicating a possible association of BMP-2 with the process of autophagy. Moreover, the reduction in the self-renewal capacity of the Abbreviations: 3 MA, 3-methyl adenine; AGG, abrus agglutinin; ATRA, all-trans-retinoic acid; ALP, alkaline phosphatase; APC, adenomatous Polyposis Coli; BMP-2, bone morphogenetic protein 2; CSCs, cancer stem cells; CRC, colorectal cancer; DAPI, 4′,6-diamidino-2-phenylindole; DMEM, Dulbecco's modified Eagle's medium; DMSO, dimethylsulfoxide; IGFBP-2, endothelial growth factor binding protein 2; EGF, epidermal growth factor; ER, endoplasmic reticulum; FBS, fetal bovine serum; FGF, fibroblast growth factor; MD, molecular dynamics; PAGE, polyacrylamide gel electrophoresis; PBS, phosphate-buffered saline; RIP II, ribosome inhibiting protein; ROS, reactive oxygen species; SDS, sodium dodecyl sulfate; shRNA, short hairpin RNA; TGF-β, Transforming growth factor-β. Molecular Carcinogenesis. 2018;1–14. wileyonlinelibrary.com/journal/mc © 2018 Wiley Periodicals, Inc. | 1