Basic Study
Copyright ©The Author(s) 2015. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Jan 28, 2015; 21(4): 1148-1157
Published online Jan 28, 2015. doi: 10.3748/wjg.v21.i4.1148
β-escin reverses multidrug resistance through inhibition of the GSK3β/β-catenin pathway in cholangiocarcinoma
Gui-Li Huang, Dong-Yan Shen, Cheng-Fu Cai, Qiu-Yan Zhang, Hong-Yue Ren, Qing-Xi Chen
Gui-Li Huang, Qiu-Yan Zhang, Qing-Xi Chen, State Key Laboratory of Cellular Stress Biology, Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, School of Life Sciences, Xiamen University, Xiamen 361005, Fujian Province, China
Dong-Yan Shen, Hong-Yue Ren, Biobank, the First Affiliated Hospital of Xiamen University, Xiamen 361003, Fujian Province, China
Cheng-Fu Cai, Department of Otorhinolaryngology, Head and Neck Surgery, the First Affiliated Hospital of Xiamen University, Xiamen 361003, Fujian Province, China
Author contributions: Huang GL, Shen DY and Cai CF contributed equally to this work; Shen DY and Chen QX designed the research; Huang GL and Cai CF performed the research; Huang GL, Zhang QY and Ren HY analyzed the data; Huang GL and Shen DY wrote the paper.
Supported by National Nature Science Foundation of China, No. 81101502; and the National Science Foundation for Fostering Talents in Basic Research of the National Natural Science Foundation of China, No. J1310027.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Qing-Xi Chen, Professor, State Key Laboratory of Cellular Stress Biology, Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, School of Life Sciences, Xiamen University, 42 Siming South Road, Xiamen 361005, Fujian Province, China. chenqxxm@126.com
Telephone: +86-592-2185487 Fax: +86-592-2185487
Received: July 14, 2014
Peer-review started: July 15, 2014
First decision: August 15, 2014
Revised: September 1, 2014
Accepted: September 29, 2014
Article in press: September 30, 2014
Published online: January 28, 2015
Processing time: 196 Days and 20.9 Hours
Abstract

AIM: To develop a safe and effective agent for cholangiocarcinoma (CCA) chemotherapy.

METHODS: A drug combination experiment was conducted to determine the effects of β-escin in combination with chemotherapy on CCA cells. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay was performed to determine the effects of β-escin and common chemotherapeutics on the proliferation of human CCA cells (QBC939, Sk-ChA-1, and MZ-ChA-1). Immunocytochemistry was used to detect the expression of P-glycoprotein (P-gp) protein. Luciferase reporter assay was used to detect the activation of the Wnt/β-catenin pathway. The protein levels of P-gp, pS9-GSK3β, pT216-GSK3β, GSK3β, β-catenin, and p-β-catenin were further confirmed by western blotting.

RESULTS: The drug sensitivity of QBC939 and QBC939/5-fluorouracil (5-FU) cells to 5-FU, vincristine sulfate (VCR), or mitomycin C was significantly enhanced by β-escin compared with either agent alone (P < 0.05). In addition, the combination of β-escin (20 μmol/L) with 5-FU and VCR was synergic with a combination index < 1. Further investigation found that the mRNA and protein expression of P-gp was down-regulated by β-escin. Moreover, β-escin induced GSK3β phosphorylation at Tyr-216 and dephosphorylation at Ser-9, resulting in phosphorylation and degradation of β-catenin. Interestingly, activation of the GSK3β/β-catenin pathway induced by Wnt3a resulted in up-regulation of P-gp, which was effectively abolished by β-escin, indicating that β-escin down-regulated P-gp expression in a GSK3β-dependent manner.

CONCLUSION: β-escin was a potent reverser of P-gp-dependent multidrug resistance, with said effect likely being achieved via inhibition of the GSK3β/β-catenin pathway and thus suggesting a promising strategy of developing combination drugs for CCA.

Keywords: β-escin; Multi-drug resistance; P-glycoprotein; GSK3β; Cholangiocarcinoma

Core tip: In our study, we received interesting and challenging results concerning the role of β-escin in reversing the multidrug resistance of cholangiocarcinoma (CCA). β-escin could enhance drug sensitivity of cholangiocarcinoma cells to common chemotherapeutics. 5-Fluorouracil, vincristine sulfate, or mitomycin C significantly reduced cell proliferation when combined with β-escin. In the molecular study, we found that β-escin could down-regulate P-gp expression via inhibiting the activation of GSK3β/β-catenin pathways. This study might offer a possible molecular basis for the further development of combinations of β-escin with common agents as a novel therapeutic approach for multidrug resistant CCA patients.