Contents lists available at ScienceDirect Phytomedicine journal homepage: www.elsevier.com/locate/phymed Original Article Aspalathin-rich green Aspalathus linearis extract suppresses migration and invasion of human castration-resistant prostate cancer cells via inhibition of YAP signaling Shih-Han Huang a,b , Yung-Hsi Kao b , Christo J.F. Muller c,d,e , Elizabeth Joubert f,g , Chih-Pin Chuu Dr. a,h,i,⁎ a Institute of Cellular and System Medicine, National Health Research Institutes, Miaoli County 35053, Taiwan b Department of Life Science, National Central University, Taoyuan City 32001, Taiwan c Biomedical Research and Innovation Platform (BRIP), South African Medical Research Council, Tygerberg 7505, South Africa d Division of Medical Physiology, Faculty of Health Sciences, Stellenbosch University, Tygerberg 7505, South Africa e Department of Biochemistry and Microbiology, University of Zululand, KwaDlangezwa 3886, South Africa f Plant Bioactives Group, Post-Harvest and Agro-Processing Technologies, Agricultural Research Council (ARC), Infruitec-Nietvoorbij, Stellenbosch 7599, South Africa g Department of Food Science, Stellenbosch University, Stellenbosch 7599, South Africa h PhD Program for Aging and Graduate Institute of Basic Medical Science, China Medical University, Taichung City 40402, Taiwan i Biotechnology Center, National Chung Hsing University, Taichung City 40227, Taiwan ARTICLEINFO Keywords: Rooibos Aspalathin Prostate cancer Migration Invasion YAP ABSTRACT Background: More than 80% of advanced prostate cancer (PCa) cases have bone metastasis, with a 5-year sur- vival rate of 25%. Previously, we reported that GRT, a standardized, pharmaceutical-grade aspalathin-rich ex- tract (12.78 g aspalathin/100 g extract), prepared from green rooibos produced from the leaves and fnestemsof Aspalathus linearis, inhibits the proliferation of PCa cells, meriting this investigation to determine if GRT can suppress the migration and invasion of castration-resistant prostate cancer (CRPC) cells. Purpose: In the present study, we investigated whether GRT extract can interfere with the migration and in- vasion of human CRPC cells. Methods: Transwell assays were used to explore the efects of GRT on the migration and invasion of CRPC cells. Micro-Western Array (MWA) and Western blot analysis were carried out to unravel the underlying molecular mechanism(s). Results: Treatment with 25–100 μg/ml GRT suppressed the migration and invasion of LNCaP C4-2B and 22Rv1 CRPC cells. MWA and Western blot analysis indicated that GRT treatment suppressed the protein level of yes- associated protein (YAP), macrophage stimulating 1 protein (MST1), phospho-MST1/phospho-MST2 T183/ T180, and paxillin, but increased the abundance of E-cadherin. Over-expression of YAP rescued the suppressive efects of GRT on migration and invasion of CRPC cells. Treatment with the major favonoid of GRT — the C- glucosyl dihydrochalcone, aspalathin — at a concentration of 75–100 μg/ml also reduced the migration and invasion of CRPC cells, and the inhibition was partially rescued by YAP over-expression. Conclusions: GRT treatment suppresses the migration and invasion of CRPC cells via inhibition of YAP signaling and paxillin. Introduction Prostate cancer (PCa) is the ffth most common cancer globally (Bray et al., 2018). The 5-year survival rate of patients with non-me- tastatic PCa is more than 98%; however, the 5-year survival rate of patients with metastatic PCa on initial diagnosis is less than 30% (Dong et al., 2019). More than 80% of advanced prostate cancer (PCa) cases have bone metastasis, with a 5-year survival rate of 25% (Koo et al., 2015). Bone is the most favorite site for metastasis of PCa cells. Androgen ablation therapy is the primary treatment for metastatic PCa. However, PCa patients receiving the androgen ablation therapy will eventually develop recurrent castration-resistant prostate cancer https://doi.org/10.1016/j.phymed.2020.153210 Received 16 December 2019; Received in revised form 28 February 2020; Accepted 16 March 2020 ⁎ Corresponding author at: Room R2-2021, Institute of Cellular and System Medicine, National Health Research Institutes, 35 Keyan Road, Zhunan, Miaoli County 350, Taiwan. E-mail address: cpchuu@gmail.com (C.-P. Chuu). Phytomedicine 69 (2020) 153210 0944-7113/ © 2020 Published by Elsevier GmbH. T