Basic Study
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World J Gastroenterol. Dec 21, 2022; 28(47): 6769-6787
Published online Dec 21, 2022. doi: 10.3748/wjg.v28.i47.6769
Dickkopf-related protein 1/cytoskeleton-associated protein 4 signaling activation by Helicobacter pylori-induced activator protein-1 promotes gastric tumorigenesis via the PI3K/AKT/mTOR pathway
Mei Luo, Yuan-Jia Chen, Yuan Xie, Qin-Rong Wang, Yi-Ning Xiang, Ni-Ya Long, Wen-Xiu Yang, Yan Zhao, Jian-Jiang Zhou
Mei Luo, Yuan-Jia Chen, Yuan Xie, Qin-Rong Wang, Yan Zhao, Jian-Jiang Zhou, Key Laboratory of Endemic and Ethnic Diseases, Ministry of Education & Key Laboratory of Medical Molecular Biology of Guizhou Province, Guizhou Medical University, Guiyang 550004, Guizhou Province, China
Yi-Ning Xiang, Wen-Xiu Yang, Department of Pathology of Affiliated Hospital, Guizhou Medical University, Guiyang 550004, Guizhou Province, China
Ni-Ya Long, Department of Neurology of Affiliated Hospital, Guizhou Medical University, Guiyang 550004, Guizhou Province, China
Author contributions: Luo M and Chen YJ contributed equally to this work; Zhou JJ and Xie Y designed the research study; Luo M, Chen YJ, Zhao Y, and Long NY performed the research; Wang QR, Xiang YN, and Yang WX collected samples and analysis data; Zhou JJ and Zhao Y wrote the manuscript; all authors have read and approve the final manuscript.
Supported by the National Natural Science Foundation of China, No. 32160166, No. 31760328, and No. 31960028; Natural Science Foundation of Guizhou Province, No. ZC[2020]4Y026, No. JC[2020]1Z010, No. JC[2020]1Y333, and No. ZK[2022]041; and Scientific Research Project of Guizhou Medical University, No. 20NSP068.
Institutional review board statement: The study was reviewed and approved by the Guizhou Medical University Ethics Committee [Approval No. 2017(43)].
Institutional animal care and use committee statement: All procedures involving animal subjects were reviewed and approved by the Animal Care Welfare Committee of Guizhou Medical University (No: 1702155).
Informed consent statement: All study participants provided informed written consent.
Conflict-of-interest statement: All authors declare no competing interests for this article.
Data sharing statement: All the data presented in the study are included in the article/supplementary materials. The datasets analyzed in the study can be found online, and the names of the datasets can be found in the article. Other data are available from the corresponding author on reasonable request.
ARRIVE guidelines statement: The authors have read the ARRIVE guidelines, and the manuscript was prepared and revised according to the ARRIVE guidelines.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (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:
Corresponding author: Jian-Jiang Zhou, Doctor, Professor, Key Laboratory of Endemic and Ethnic Diseases, Ministry of Education & Key Laboratory of Medical Molecular Biology of Guizhou Province, Guizhou Medical University, No. 9 Beijing Road, Guiyang 550004, Guizhou Province, China.
Received: October 12, 2022
Peer-review started: October 12, 2022
First decision: October 20, 2022
Revised: November 5, 2022
Accepted: November 30, 2022
Article in press: November 30, 2022
Published online: December 21, 2022

Gastric cancer (GC) is a common malignant tumor with high incidence and mortality rates globally, especially in East Asian countries. Helicobacter pylori (H. pylori) infection is a significant and independent risk factor for GC. However, its underlying mechanism of action is not fully understood. Dickkopf-related protein (DKK) 1 is a Wnt signaling antagonist, and cytoskeleton-associated protein (CKAP) 4 is a newly identified DKK1 receptor. Recent studies found that the binding of DKK1 to CAKP4 mediated the procancer signaling of DKK1 inde-pendent of Wnt signaling. We hypothesize that H. pylori-induced activation of DKK1/CKAP4 signaling contributes to the initiation and progression of GC.


To investigate the interaction of H. pylori infection, DKK1 and CAKP4 in GC, as well as the underlying molecular mechanisms.


RNA sequencing was used to identify differentially expressed genes (DEGs) between H. pylori-infected and uninfected primary GC cells. Gain- and loss-of-function experiments were performed to verify the H. pylori-induced upregulation of activator protein-1 (AP-1) in GC cells. A dual-luciferase reporter assay and co-immunoprecipitation were used to determine the binding of AP-1 to the DKK1 promoter and DKK1 to CKAP4. Western blotting and immunohistochemistry detected the expression of DKK1, CKAP4, and phos-phatidylinositol 3-kinase (PI3K) pathway-related proteins in GC cells and tissues. Functional experiments and tumorigenicity in nude mice detected malignant behavior of GC cells in vitro and in vivo.


We identified 32 DEGs between primary GC cells with and without H. pylori infection, including JUN, fos-like antigen-1 (FOSL1), and DKK1, and confirmed that the three proteins and CKAP4 were highly expressed in H. pylori-infected GC cells, H. pylori-infected gerbil gastric tissues, and human GC tissues. JUN and FOSL1 form AP-1 to transcriptionally activate DKK1 expression by binding to the DKK1 promoter. Activated DKK1 bound to CKAP4, but not the most common Wnt coreceptor low-density lipoprotein receptor-related protein 5/6, to promote GC cell growth, colony formation, migration, invasion, and xenograft tumor growth in nude mice. All these effects were driven by activation of the PI3K/AKT/mammalian target of rapamycin (mTOR) pathway. Targeting the PI3K signaling pathway by LY294002 inhibited DKK1-mediated CKAP4/PI3K signaling activity and the malignant behavior of GC cells.


H. pylori induces JUN and FOSL1 expression to form AP-1, which transcriptionally activates DKK1. Binding of DKK1 to KAKP4 contributes to gastric tumorigenesis via the PI3K/AKT/mTOR pathway.

Keywords: Gastric cancer, Helicobacter pylori, Dickkopf-related protein 1, Cytoskeleton-associated protein 4, Phosphatidylinositol 3-kinase pathway

Core Tip: Helicobacter pylori (H. pylori) infection is the most significant risk factor for gastric cancer (GC). More than half of the global population has H. pylori infection, and 1%-3% of the infected individuals develop GC, but the mechanism behind this link remains unclear. Here, we identified 32 highly expressed genes in H. pylori-infected GC cells and demonstrated that H. pylori-induced high expression of JUN and fos-like antigen-1 formed activator protein-1 to transcriptionally activate dickkopf-related protein (DKK) 1, which by binding to cytoskeleton-associated protein 4 (CKAP4) receptor activated the PI3K/AKT/mammalian target of rapamycin pathway and, consequently, gastric tumorigenesis. Targeting the DKK1/CKAP4 interaction may be a novel strategy to treat GC.