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

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 TIMSCs 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.