Supporting data for "CX3CL1 recruits CX3CR1pos macrophages to promote tumor progression in intrahepatic cholangiocarcinoma"

  

Intrahepatic cholangiocarcinoma (iCCA) is the second most prevalent liver malignancy with a worse prognosis. It is characterized by a highly desmoplastic tumor microenvironment (TME) featured with abundant macrophages. Chemokines orchestrate the recruitment and infiltration of macrophages into the TME. The significance of CX3CR1^pos macrophages with pro-tumoral features has been documented in several tumors other than iCCA. We aimed to investigate the role of the CX3CL1/CX3CR1 signaling in the progression of iCCA.

The data are related to the following contents. CX3CL1 expression was analyzed in two independent clinical cohorts (HKU and external cohorts). The clinical significances of CX3CL1 and CX3CR1^pos macrophages were evaluated by Cox proportional hazards model. Phenotypes and functions of tumor-infiltrated and monocyte-derived CX3CR1^pos and CX3CR1^neg macrophages were also assessed via mRNA sequencing and flow cytometry. The interactions between iCCA cells and CX3CR1^pos macrophages were evaluated both in vitro and in vivo. The mechanisms for CX3CR1^pos macrophages contribute to the immunosuppressive microenvironment and tumor invasiveness were investigated in cells and an orthotopic model. The therapeutic potential of a CX3CR1 antagonist (AZD8797) targeting the CX3CL1-CX3CR1 axis was explored in vivo. 

Our data revealed that CX3CL1 was the most frequently up-regulated chemokine of iCCA in HKU and TCGA cohorts. Overexpression of CX3CL1 in iCCA tissue indicated tumor invasiveness and poor prognosis in both HKU and external validation cohorts. CX3CR1^pos macrophages were independent risk factors for both disease-free and overall survival of iCCA. CX3CL1 facilitated the infiltration of CX3CR1^pos macrophages into the TME of iCCA. CX3CR1^pos macrophages not only contributed to immunosuppressive TME through secreting IL10, but also promoted an invasive phenotype of iCCA cells via CCL5-mediated epithelial-mesenchymal transition. It is demonstrated that the tumor volume of CX3CL1-high-expressing xenografts was markedly more extensive than those of CX3CL1-low-expressing xenografts. Higher rate of lung metastases was shown in the group with CX3CL1-high-expressing xenografts compared to the control group. The protumoral effects of CX3CL1 cannot be achieved without the presence of CX3CR1^pos macrophages. Notably, blockage of the CX3CL1/CX3CR1 axis using AZD8797 inhibited the growth and metastasis of iCCA in vivo through the attenuation of immunosuppressive environment.