CCL18 secreted from M2 macrophages promotes migration and invasion via the PI3K/Akt pathway in gallbladder cancer
- 228 Downloads
The presence of M2 macrophages within primary tumors has been correlated with a poor prognosis for many types of cancer. However, little is known about the role of M2 macrophages in gallbladder cancer (GBC).
The number of M2 macrophages in 78 GBC and 16 normal gallbladder tissue samples was assessed by immunohistochemistry. The THP-1 monocyte cell line was differentiated into M2 macrophages and co-cultured with GBC-derived cell lines. The effect of M2 macrophages on promoting GBC cell migration and invasion was analyzed using migration, invasion and scratch wound healing assays. Western blotting and real-time PCR were used to assess the expression of epithelial-mesenchymal transition (EMT) markers and the activation status of the PI3K/Akt signaling pathway in GBC cells co-cultured with THP-1-derived macrophages.
The average number of M2 macrophages was found to be significantly higher in GBC tissues than in normal gallbladder tissues. We also found that GBC patients with higher M2 macrophage counts exhibited poorer overall survival rates. Co-culture with M2 macrophages significantly promoted the migration, invasion and EMT of GBC cells. Moreover, we found that CCL18 secreted from M2 macrophages had the same effect on GBC cells as M2 macrophages. Blocking the function of CCL18 with a neutralizing antibody reversed this effect. Finally, we found that M2 macrophages could activate PI3K/Akt signaling in GBC cells, thereby leading to migration, invasion and EMT of these cells.
Our findings contribute to our understanding of the role of chronic inflammation in GBC development and progression, and may offer potential therapeutic targets for GBC.
KeywordsGallbladder cancer M2 macrophages CCL18 Epithelial-mesenchymal transition Chronic inflammation
This work was partially supported by the National Natural Science Foundation of China (Grant No. 81672405), the Key Project of the Natural Science Foundation of Guangdong Province, China (Grant No. 4210016041), the Science and Technology Program of Guangzhou, China (Grant No. 4250016043), a grant from the Guangdong Science and Technology Department (2015B050501004), Grant  163 from the Key Laboratory of Malignant Tumor Molecular Mechanism and Translational Medicine of the Guangzhou Bureau of Science and Information Technology, and Grant KLB09001 from the Key Laboratory of Malignant Tumor Gene Regulation and Target Therapy of the Guangdong Higher Education Institutes. We thank Pro. Dong Yin from Sun Yat-Sen Memorial Hospital and Dr. Hui Shen from Renji Hospital, School of Medicine, Shanghai Jiao Tong University, for their technical support and Dr. Jing Wei and Fang Su from Sun Yat-Sen Memorial Hospital for conducting the flow cytometry experiments.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
All procedures performed in studies involving human participants were conducted in accordance with the ethical standards of the Institutional Research Committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
- 3.R. Hundal, E.A. Shaffer, Gallbladder cancer: Epidemiology and outcome. Clin Epidemiol 6, 99–109 (2014)Google Scholar
- 11.S. Su, Q. Liu, J. Chen, J. Chen, F. Chen, C. He, D. Huang, W. Wu, L. Lin, W. Huang, Z. J, X. Cui, F. Zheng, H. Li, H. Yao, F. Su, E. Song, A positive feedback loop between mesenchymal-like cancer cells and macrophages is essential to breast cancer metastasis. Cancer Cell 25, 605–620 (2014)CrossRefGoogle Scholar
- 20.J.A. Espinoza, C. Bizama, P. García, C. Ferreccio, M. Javle, J.F. Miquel, J. Koshiol, J.C. Roa, The inflammatory inception of gallbladder cancer. Biochim Biophys Acta 1865, 245–254 (2016)Google Scholar
- 22.P. Italiani, D. Boraschi, From monocytes to M1/M2 macrophages: Phenotypical vs. functional differentiation. Front Immuno l5, 514 (2014)Google Scholar