Basic Study
Copyright ©The Author(s) 2017. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Dec 28, 2017; 23(48): 8512-8525
Published online Dec 28, 2017. doi: 10.3748/wjg.v23.i48.8512
Astragaloside IV inhibits pathological functions of gastric cancer-associated fibroblasts
Zhen-Fei Wang, Da-Guang Ma, Zhe Zhu, Yong-Ping Mu, Yong-Yan Yang, Li Feng, Hao Yang, Jun-Qing Liang, Yong-Yan Liu, Li Liu, Hai-Wen Lu
Zhen-Fei Wang, Da-Guang Ma, Yong-Ping Mu, Yong-Yan Yang, Hai-Wen Lu, Laboratory for Tumor Molecular Diagnosis, Affiliated People’s Hospital of Inner Mongolia Medical University, Huhhot 010020, Inner Mongolia Autonomous Region, China
Zhe Zhu, Jun-Qing Liang, Yong-Yan Liu, Department of cytotherapy for tumors, Affiliated People’s Hospital of Inner Mongolia Medical University, Huhhot 010020, Inner Mongolia Autonomous Region, China
Li Feng, Department of Abdominal Tumor Surgery, Affiliated People’s Hospital of Inner Mongolia Medical University, Huhhot 010020, Inner Mongolia Autonomous Region, China
Hao Yang, Department of Radiotherapy, Affiliated People’s Hospital of Inner Mongolia Medical University, Huhhot 010020, Inner Mongolia Autonomous Region, China
Li Liu, Central Laboratory, People’s Hospital of Wuhai City, Wuhai 016000, Inner Mongolia Autonomous Region, China
Hai-Wen Lu, Affiliated Hospital of Inner Mongolia Medical University, Huhhot 010050, Inner Mongolia Autonomous Region, China
Author contributions: Wang ZF, Ma DG, Lu HW and Liu L designed the research; Wang ZF, Zhu Z, Mu YP, Yang YY, Yang H and Liang JQ performed the research; Feng L and Liu YY analyzed the data; Liu L and Wang ZF wrote the paper.
Supported by the National Natural Science Foundation of China, No. 81760552; the Program of the Inner Mongolia Natural Science Foundation, No. 2016MS0824 and No. 2015MS0896; the Program of “Keji Baiwan Gongcheng” of Inner Mongolia Medical University, No. YKD2015KJBW008; and the Supporting Program for Outstanding Youth in Science and Technology of Inner Mongolia Autonomous Region, No. NJYT-17-B30.
Institutional review board statement: The study was reviewed and approved by the Affiliated People’s Hospital of Inner Mongolia Medical University.
Conflict-of-interest statement: To the best of our knowledge, no conflict of interest exists.
Data sharing statement: No additional data are available.
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: Hai-Wen Lu, PhD, Professor, Affiliated Hospital, Inner Mongolia Medical University, Huhhot 010050, Inner Mongolia Autonomous Region, China. haiwen_l@yeah.net
Telephone: +86-15548798800 Fax: +86-471-3360302
Received: July 25, 2017
Peer-review started: July 25, 2017
First decision: September 14, 2017
Revised: September 29, 2017
Accepted: November 22, 2017
Article in press: November 22, 2017
Published online: December 28, 2017
ARTICLE HIGHLIGHTS
Research background

Currently, most chemotherapeutic agents perform by directly acting on cancer cells. They have limited efficacy and generate adverse reactions. Cancer-associated fibroblasts, the dominant cell population within cancer stroma, create favorable conditions for cancer initiation and progression. Preventing cancer-associated fibroblasts from nourishing and supporting cancer cells is a novel and effective anti-cancer pathway.

Research motivation

So far, few effective drugs have been found against cancer-associated fibroblasts. Developing effective inhibitors of cancer-associated fibroblasts is an urgent issue for cancer therapy.

Research objectives

Chinese herbs can regulate and improve patients’ internal environment to restore various tissues and cells to their normal states and enhance their functions. It is promising to find effective inhibitors of cancer-associated fibroblasts from Chinese herbs. Astragaloside IV is a cycloartane-type triterpene glycoside isolated from Radix astragali. Here, for the first time, we studied whether astragaloside IV can inhibit the pathological functions of cancer-associated fibroblasts, and explored the mechanism underlying the inhibitory effect. The research will provide valuable information on the feasibility of developing cancer-associated fibroblast inhibitors from Chinese herbs.

Research methods

Paired gastric normal fibroblast (GNF) and gastric cancer-associated fibroblast (GCAF) cultures were established from resected tissues. GCAFs were treated with vehicle control or different concentrations of astragaloside IV. Conditioned media were prepared from GNFs, GCAFs, control-treated GCAFs, and astragaloside IV-treated GCAFs, and used to culture BGC-823 human gastric cancer cells. Proliferation, migration, and invasion capacities of BGC-823 cells were determined with MTT, wound healing, and Transwell invasion assays, respectively. The expression of microRNAs in the GCAFs was detected by RT-qPCR. The expression and secretion of the oncogenic factor M-CSF and the tumor suppressive factor TIMP2 in different groups of GCAFs were determined by Western blot and ELISA analysis, respectively. The expression of the oncogenic pluripotency factors SOX2 and NANOG in BGC-823 cells cultured with different conditioned media was also examined by RT-qPCR and Western blot analysis.

Research results

GCAFs displayed higher capacities to induce BGC-823 cell proliferation, migration, and invasion than GNFs. Astragaloside IV treatment strongly inhibited the proliferation-, migration- and invasion-promoting capacities of GCAFs. Compared with GNFs, GCAFs expressed a lower level of mir-RNA-214 and a higher level of microRNA-301a. Astragaloside IV treatment significantly up-regulated microRNA-214 expression and down-regulated microRNA-301a expression in GCAFs. Reestablishing the microRNA expression balance subsequently suppressed M-CSF production and secretion, and elevated TIMP2 production and secretion. Consequently, the ability of GCAFs to increase SOX2 and NANOG expression in BGC-823 cells was abolished by astragaloside IV. These results demonstrate that astragaloside IV is promisingly a potent therapeutic agent regulating tumor microenvironment.

Research conclusions

This study shows for the first time that astragaloside IV can effectively inhibit the pathological functions of cancer-associated fibroblasts, and that astragaloside IV is useful for cancer therapy by regulating tumor microenvironment.

Previous studies focused on investigating the abnormal mir-RNA expression in cancer cells. Our results showed that the dysregulation in mir-RNA expression is an important cause of pathological functions of cancer-associated fibroblasts. Correcting the mir-RNA expression dysregulation in cancer associated fibroblasts is a new anti-cancer mechanism of Chinese herbs. Chinese herbs are a valuable source for developing new drugs regulating tumor microenvironment.

The method used in this study was to culture gastric cancer cells with the conditioned medium from GCAFs. In the culture system, GCAFs promoted the malignant behaviors of gastric cancer cells. Astragaloside IV inhibited the malignancy-promoting capacity of GCAFs through down-regulating the expression of oncogenic factors and up-regulating the expression of tumor suppressive factors. Also, we found that promoting the generation of gastric cancer stem cells and supporting their malignant phenotypes are an important oncogenic mechanism of GCAFs. Importantly, some Chinese herbs can destroy the niche of gastric cancer stem cells by acting on GCAFs.

Research perspectives

The concept of holism of traditional Chinese medicine is valuable for guidance of developing new anti-cancer drugs. Non-toxic Chinese herbs may have great values in cancer therapy by regulating the tumor microenvironment. Chinese herbs that can regulate the tumor microenvironment are a promising resource for the development of novel anti-cancer drugs.