Mesenchymal stem cells in inflammatory microenvironment potently promote metastatic growth of cholangiocarcinoma via activating Akt/NF-κB signaling by paracrine CCL5

// Wei Zhong 1, 2 , Yinping Tong 1 , Yang Li 1 , Jiahui Yuan 1 , Shaoping Hu 1 , Tianhui Hu 1 and Gang Song 1 1 Cancer Research Center, Medical College of Xiamen University, Xiamen 361102, China 2 Department of General Surgery, The Affiliated Southeast Hospital of Xiamen University, Zhangzhou 363000, China Correspondence to: Gang Song, email: gangsongsd@xmu.edu.cn Keywords: cholangiocarcinoma, mesenchymal stem cell, inflammatory microenvironment, CCL5 Received: June 15, 2016      Accepted: April 18, 2017      Published: May 11, 2017 ABSTRACT Our previous work has demonstrated that mesenchymal stem cells (MSCs) could induce metastatic growth of the inflammation-related cholangiocarcinoma (CCA). However, the functional mechanism of MSCs on CCA progression in the early inflammatory microenvironment remained undetermined. Here, we showed that TNF-α and IFN-γ-induced inflammatory microenvironment stimulated the expression of TNF-α, CCL5, IL-6, IDO, and activated the NF-κB signaling with p65 nuclear translocation in MSCs cells. CCA cell lines QBC939 and Mz-chA-1 exposed to the conditioned medium of MSCs after being stimulated by TNF-α and IFN-γ (TI-CM) exhibited enhanced mobility. Moreover, MSCs pre-stimulated by both inflammatory cytokines (TI-MSCs) increased tumor metastasis in vivo . The conditioned medium of TI-MSCs stimulated the transcription of snail , slug , ZEB1 and ZEB2 . Next, the expression of CCL5 of TI-MSCs was verified by ELISA, which indicated that MSCs contributed to CCA migration and metastasis in a paracrine fashion. CCA cells treated with TI-CM up-regulated CCA chemokine receptors, especially CCR5; CCL5 neutralizing antibody or CCR5 inhibitor Maraviroc inhibited the effects of MSCs on CCA cells migration. We also found that Akt/NF-κB signaling was activated by CCL5/CCR5 axis, which increased the expression of MMP2, MMP9. Together, these findings suggest that MSCs in tumor inflammatory microenvironment are elicited of CCL5, which activate AKT/NF-κB signaling and lead to metastatic growth of CCA cells.