Basic Study
Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Mar 14, 2016; 22(10): 2971-2980
Published online Mar 14, 2016. doi: 10.3748/wjg.v22.i10.2971
Synergistic anticancer properties of docosahexaenoic acid and 5-fluorouracil through interference with energy metabolism and cell cycle arrest in human gastric cancer cell line AGS cells
Kun Gao, Qi Liang, Zhi-Hao Zhao, You-Fen Li, Shu-Feng Wang
Kun Gao, You-Fen Li, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an 710049, Shaanxi Province, China
Qi Liang, Department of Anesthesiology, Xi’an Traditional Chinese Medicine Hospital, Xi’an 710021, Shaanxi Province, China
Zhi-Hao Zhao, Shu-Feng Wang, Department of General Surgery, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an 710061, Shaanxi Province, China
Author contributions: Gao K, Liang Q and Zhao ZH contributed equally to this work; Wang SF conceived the idea and designed the research; Zhao ZH and Gao K performed all assays and cell culture experiments; Li YF, Liang Q and Wang SF analyzed and interpreted the data; Liang Q and Wang SF wrote the manuscript; Wang SF have read and approved the final version of the manuscript.
Conflict-of-interest statement: We have no conflicts of interest to declare.
Data sharing statement: Technical appendix, statistical code and dataset are available from the corresponding author at dawn@mail.xjtu.edu.cn.
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: Shu-Feng Wang, MD, PhD, Department of General Surgery, The First Affiliated Hospital of Xi’an Jiaotong University, Yanta West Road 277, Xi’an 710061, Shaanxi Province, China. dawn@mail.xjtu.edu.cn
Telephone: +86-29-85323870 Fax: +86-29-85323870
Received: September 2, 2015
Peer-review started: September 17, 2015
First decision: November 5, 2015
Revised: November 22, 2015
Accepted: December 19, 2015
Article in press: December 21, 2015
Published online: March 14, 2016
Processing time: 176 Days and 8 Hours
Abstract

AIM: To explore the synergistic effect of docosahexaenoic acid (DHA)/5-fluorouracil (5-FU) on the human gastric cancer cell line AGS and examine the underlying mechanism.

METHODS: AGS cells were cultured and treated with a series of concentrations of DHA and 5-FU alone or in combination for 24 and 48 h. To investigate the synergistic effect of DHA and 5-FU on AGS cells, the inhibition of cell proliferation was determined by MTT assay and cell morphology. Flow cytometric analysis was also used to assess cell cycle distribution, and the expression of mitochondrial electron transfer chain complexes (METCs) I, II and V in AGS cells was further determined by Western blot analysis.

RESULTS: DHA and 5-FU alone or in combination could markedly suppress the proliferation of AGS cells in a significant time and dose-dependent manner. DHA markedly strengthened the antiproliferative effect of 5-FU, decreasing the IC50 by 3.56-2.15-fold in an apparent synergy. The morphological changes of the cells were characterized by shrinkage, cell membrane blebbing and decreased adherence. Cell cycle analysis showed a shift of cells into the G0/G1 phase from the S phase following treatment with DHA or 5-FU (G0/G1 phase: 30.04% ± 1.54% vs 49.05% ± 6.41% and 63.39% ± 6.83%, respectively, P < 0.05; S phase: 56.76% ± 3.14% vs 34.75% ± 2.35% and 25.63% ± 2.21%, respectively, P < 0.05). Combination treatment of DHA and 5-FU resulted in a significantly larger shift toward the G0/G1 phase and subsequent reduction in S phase (G0/G1 phase: 69.06% ± 2.63% vs 49.05% ± 6.41% and 63.39% ± 6.83%, respectively, P < 0.05; S phase: 19.80% ± 4.30% vs 34.75% ± 2.35% and 25.63% ± 2.21%, respectively, P < 0.05). This synergy was also reflected in the significant downregulation of the expression of METCs in AGS cells.

CONCLUSION: Synergistic anticancer properties of DHA and 5-FU may involve interference with energy production of AGS cells via downregulation of METCs and cell cycle arrest.

Keywords: Docosahexaenoic acid; Gastric cancer; 5-fluorouracil; Cell line; Mitochondria

Core tip: We explored the synergistic anticancer properties of docosahexaenoic acid (DHA) and 5-fluorouracil (5-FU) against gastric cancer cells and the underlying mechanism. DHA and 5-FU alone or in combination could markedly suppress the proliferation of AGS cells in a significant time and dose-dependent manner. Co-administration of DHA with 5-FU resulted in a significantly larger shift toward the G0/G1 phase and a significant downregulation of the expression of mitochondrial electron transfer chain complexes in AGS cells. The associated mechanism may involve interference with energy production of AGS cells via downregulation of mitochondrial electron transfer chain complexes and cell cycle arrest in G0/G1 phase.