American Chemical Society
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Structure–Activity Relationship Study Enables the Discovery of a Novel Berberine Analogue as the RXRα Activator to Inhibit Colon Cancer

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posted on 2020-05-28, 17:39 authored by Beibei Xu, Xunjin Jiang, Jing Xiong, Jun Lan, Yuan Tian, Linhai Zhong, Xinquan Wang, Ning Xu, Hanwei Cao, Wenqing Zhang, Hao Zhang, Xiaoting Hong, Yan-yan Zhan, Yandong Zhang, Tianhui Hu
We reported recently that berberine (Ber), a traditional oriental medicine to treat gastroenteritis, binds and activates retinoid X receptor α (RXRα) for suppressing the growth of colon cancer cells. Here, we extended our studies based on the binding mode of Ber with RXRα by design, synthesis, and biological evaluation of a focused library of 15 novel Ber analogues. Among them, 3,9-dimethoxy-5,6-dihydroisoquinolino­[3,2-a]­isoquinolin-7-ium chloride (B-12) was identified as the optimal RXRα activator. More efficiently than Ber, B-12 bound and altered the conformation of RXRα/LBD, thereby suppressing the Wnt/β-catenin pathway and colon cancer cell growth via RXRα mediation. In addition, B-12 not only preserved Ber’s tumor selectivity but also greatly improved its bioavailability. Remarkably, in mice, B-12 did not show obvious side effects including hypertriglyceridemia as other RXRα agonists or induce hepatorenal toxicity. Together, our study describes an approach for the rational design of Ber-derived RXRα activators as novel effective antineoplastic agents for colon cancer.