Basic Study
Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Apr 28, 2016; 22(16): 4149-4159
Published online Apr 28, 2016. doi: 10.3748/wjg.v22.i16.4149
Thymoquinone inhibits proliferation in gastric cancer via the STAT3 pathway in vivo and in vitro
Wen-Qian Zhu, Jun Wang, Xu-Feng Guo, Zhou Liu, Wei-Guo Dong
Wen-Qian Zhu, Jun Wang, Xu-Feng Guo, Zhou Liu, Wei-Guo Dong, Department of Gastroenterology, Renmin Hospital of Wuhan University, Key Laboratory of Hubei Province for Digestive System Disease, Wuhan 430060, Hubei Province, China
Author contributions: Zhu WQ and Wang J contributed equally to this work; Zhu WQ, Wang J, Guo XF, Liu Z and Dong WG designed research; Zhu WQ, Wang J, Guo XF and Liu Z performed research; Wang J, Zhu WQ and Guo XF contributed new reagents/analytic tools; Wang J, Zhu WQ, Guo XF and Liu Z analyzed data; and Zhu WQ and Wang J wrote the paper.
Supported by The National Natural Science Foundation of China, No. 81372551.
Institutional review board statement: This study was reviewed and approved by the Wuhan University Institutional Review Board.
Institutional animal care and use committee statement: All procedures involving animals were reviewed and approved by the Institutional Animal Care and Use Committee of the Wuhan University.
Conflict-of-interest statement: We declare that we have no financial and personal relationships with other people or organizations that can inappropriately influence our work, there is no professional or other personal interest of any nature or kind in any product, service and/or company that could be construed as influencing the position presented in, or the review of, the manuscript entitled, “Thymoquinone inhibits proliferation in gastric cancer via the STAT3 pathway in vivo and in vitro”.
Data sharing statement: Technical appendix, original data, images, and statistical code of this manuscript are available from the corresponding author at dwg@whu.edu.cn. Participants gave informed consent for data sharing.
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: Dr. Wei-Guo Dong, Professor, Department of Gastroenterology, Renmin Hospital of Wuhan University, Key Laboratory of Hubei Province for Digestive System Disease, Hubei Zhang Road, Wuhan 430060, Hubei Province, China. dwg@whu.edu.cn
Telephone: +86-27-88041911 Fax: +86-27-88042292
Received: January 23, 2016
Peer-review started: January 25, 2016
First decision: February 18, 2016
Revised: February 26, 2016
Accepted: March 18, 2016
Article in press: March 18, 2016
Published online: April 28, 2016
Abstract

AIM: To elucidate the mechanism of thymoquinone (TQ)-induced apoptosis in human gastric cancer cells in vitro and in vivo.

METHODS: HGC27, BGC823, and SGC7901 cells were cultured in vitro and treated with TQ (0, 10, 25, 50, 75, 100, 125 μmol/L) for 12 h, 24 h, and 36 h, and then the proliferation inhibitory rates were detected by methylthiazole tetrazolium assay. Apoptosis was observed after Hoechst staining. The protein expressions of signal transducer and activator of transcription (STAT)3, p-STAT3, STAT5, p-STAT5, phospho-janus-activated kinase 2 (JAK2), JAK2, p-Src, Src, glyceraldehyde-3-phosphate dehydrogenase, lamin-A, survivin, Cyclin D, Bcl-2, Bax, peroxisome proliferator activated receptor, and caspase-3,7,9 were detected by western blot. Cell cycle and apoptosis were determined with flow cytometry. TQ induced dose-dependent apoptotic cell death in HGC27 cells was measured by Annexin V-fluorescein isothiocyanate (FITC)/propidium iodide (PI) analysis and Hoechst 33258.

RESULTS: TQ inhibited the phosphorylation of STAT3 but not STAT5. TQ-induced downregulation of STAT3 activation was associated with a reduction in JAK2 and c-Src activity. TQ also downregulated the expression of STAT3-regulated genes, such as Bcl-2, cyclin D, survivin, and vascular endothelial growth factor, and activated caspase-3,7,9. Consistent with the in vitro results, TQ was significantly effective as an antitumor agent in a xenograft tumor mouse model.

CONCLUSION: This study provides strong evidence that downregulation of the STAT3 signaling pathway mediates TQ-induced apoptosis in gastric cancer.

Keywords: Thymoquinone, Gastric cancer, STAT3, Proliferation, Apoptosis

Core tip: Thymoquinone (TQ) has been demonstrated to exert biological activity in gastric cancer. However, the specific mechanism of TQ in gastric cancer has not been examined. In order to elucidate the mechanism of TQ-induced apoptosis in human gastric cancer cells, we investigated the effects of TQ on signal transducer and activator of transcription (STAT)3 and its related pathway in vitro and in vivo.