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Liu G, Shi A, Wang N, Li M, He X, Yin C, Tu Q, Shen X, Tao Y, Wang Q, Yin H. Polyphenolic Proanthocyanidin-B2 suppresses proliferation of liver cancer cells and hepatocellular carcinogenesis through directly binding and inhibiting AKT activity. Redox Biol 2020; 37:101701. [PMID: 32863234 PMCID: PMC7472926 DOI: 10.1016/j.redox.2020.101701] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 08/18/2020] [Accepted: 08/19/2020] [Indexed: 12/20/2022] Open
Abstract
The well-documented anticarcinogenic properties of natural polyphenolic proanthocyanidins (OPC) have been primarily attributed to their antioxidant and anti-inflammatory potency. Emerging evidence suggests that OPC may target canonical oncogenic pathways, including PI3K/AKT; however, the underlying mechanism and therapeutic potential remain elusive. Here we identify that proanthocyanidin B2 (OPC-B2) directly binds and inhibits AKT activity and downstream signalling, thereby suppressing tumour cell proliferation and metabolism in vitro and in a xenograft and diethyl-nitrosamine (DEN)-induced hepatocellular carcinoma (HCC) mouse models. We further find that OPC-B2 binds to the catalytic and regulatory PH domains to lock the protein in a closed conformation, similar to the well-studied AKT allosteric inhibitor MK-2206. Molecular docking and dynamic simulation suggest that Lys297 and Arg86 are critical sites of OPC-B2 binding; mutation of Lys297 or Arg86 to alanine completely abolishes the antitumor effects of OPC-B2 but not MK-2206. Together, our study reveals that OPC-B2 is a novel allosteric AKT inhibitor with potent anti-tumour efficacy beyond its antioxidant and anti-inflammatory properties.
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Affiliation(s)
- Guijun Liu
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, Shanghai Institute of Nutrition and Health (SINH), Chinese Academy of Sciences (CAS), Shanghai, 200031, China; University of the Chinese Academy of Sciences, CAS, Beijing, China
| | - Aimin Shi
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences (CAAS), Beijing, 100193, China
| | - Ningning Wang
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, Shanghai Institute of Nutrition and Health (SINH), Chinese Academy of Sciences (CAS), Shanghai, 200031, China; University of the Chinese Academy of Sciences, CAS, Beijing, China
| | - Min Li
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, Shanghai Institute of Nutrition and Health (SINH), Chinese Academy of Sciences (CAS), Shanghai, 200031, China; University of the Chinese Academy of Sciences, CAS, Beijing, China
| | - Xuxiao He
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, Shanghai Institute of Nutrition and Health (SINH), Chinese Academy of Sciences (CAS), Shanghai, 200031, China; University of the Chinese Academy of Sciences, CAS, Beijing, China
| | - Chunzhao Yin
- University of the Chinese Academy of Sciences, CAS, Beijing, China; School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Qiaochu Tu
- University of the Chinese Academy of Sciences, CAS, Beijing, China; School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Xia Shen
- University of the Chinese Academy of Sciences, CAS, Beijing, China; School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Yongzhen Tao
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, Shanghai Institute of Nutrition and Health (SINH), Chinese Academy of Sciences (CAS), Shanghai, 200031, China.
| | - Qiang Wang
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences (CAAS), Beijing, 100193, China.
| | - Huiyong Yin
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, Shanghai Institute of Nutrition and Health (SINH), Chinese Academy of Sciences (CAS), Shanghai, 200031, China; University of the Chinese Academy of Sciences, CAS, Beijing, China; Key Laboratory of Food Safety Risk Assessment, Ministry of Health, Beijing, China; School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
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