The Role of CXCL16 in the Pathogenesis of Cancer and Other Diseases.

CXCL16 is a chemotactic cytokine belonging to the α-chemokine subfamily. It plays a significant role in the progression of cancer, as well as the course of atherosclerosis, renal fibrosis, and non-alcoholic fatty liver disease (NAFLD). Since there has been no review paper discussing the importance of this chemokine in various diseases, we have collected all available knowledge about CXCL16 in this review. In the first part of the paper, we discuss background information about CXCL16 and its receptor, CXCR6. Next, we focus on the importance of CXCL16 in a variety of diseases, with an emphasis on cancer. We discuss the role of CXCL16 in tumor cell proliferation, migration, invasion, and metastasis. Next, we describe the role of CXCL16 in the tumor microenvironment, including involvement in angiogenesis, and its significance in tumor-associated cells (cancer associated fibroblasts (CAF), microglia, tumor-associated macrophages (TAM), tumor-associated neutrophils (TAN), mesenchymal stem cells (MSC), myeloid suppressor cells (MDSC), and regulatory T cells (Treg)). Finally, we focus on the antitumor properties of CXCL16, which are mainly caused by natural killer T (NKT) cells. At the end of the article, we summarize the importance of CXCL16 in cancer therapy.

Soluble CXCL16 promotes TNF-α-induced apoptosis in DLBCL via the AMAD10-NF-κB regulatory feedback loop.

We had previously identified that the co-expression of transmembrane CXCL16 (TM-CXCL16) and its receptor CXCR6 is an independent risk factor for poor survival in patients with diffuse large B-cell lymphoma (DLBCL). However, the impact of the soluble form of CXCL16 (sCXCL16) on the pathogenesis of DLBCL remains unknown. In the present study, the synergistic effect of sCXCL16 and tumor necrosis factor α (TNF-α) on apoptosis in DLBCL cell lines (OCI-LY8 and OCI-LY10) was investigated in vitro. sCXCL16 reinforced TNF-α-mediated inhibition of DLBCL cell proliferation, as determined by the cell counting kit-8 assay. The results of annexin V staining showed that sCXCL16 enhanced TNF-α-induced apoptosis in OCI-LY8 and OCI-LY10 cells through a death receptor-caspase signaling pathway. The results of gene microarray suggested a significant upregulation of differentially expressed genes in the TNF signaling pathway. sCXCL16 increased the concentration of extracellular TNF-α by binding to CXCR6 to activate the nuclear factor-κB (NF-κB) signaling pathway. TNF-α also induced the secretion of sCXCL16 by increasing the expression of ADAM10, which is known to cleave TM-CXCL16 to yield sCXCL16. Moreover, bioinformatics analysis revealed that elevated TNF-α and ADAM10 expression levels in tumor tissues predicted better survival in patients with DLBCL. Thus, our study suggests that sCXCL16 enhances TNF-α-induced apoptosis of DLBCL cells, which may involve a positive feedback loop consisting of TNF-α, ADAM10, sCXCL16, and members of the NF-κB pathway. sCXCL16 and TNF-α may be used as prognostic markers in the clinic, and their combinational use is a promising approach in the context of DLBCL therapy.

The Role of Autophagy and the Chemokine (C-X-C Motif) Ligand 16 During Acute Lung Injury in Mice.

BACKGROUND Acute lung injury (ALI) is responsible for mortality in hospitalized patients. Autophagy can negatively regulate inflammatory response, and CXCL16 (chemokine (C-X-C motif) ligand 16) is a kind of chemokine, which is closely related to the inflammatory response. However, the relationship between autophagy and CXCL16 in ALI is still unclear. This study aimed to investigate the role of autophagy and chemokine CXCL16 in ALI in mice. MATERIAL AND METHODS Thirty-two male C57BL/6 mice were divided into four groups. The control group (C group) was given normal saline through intraperitoneal injection. The L group was given LPS (lipopolysaccharide) at 30 mg/kg to construct an ALI model. The 3-MA group received an intraperitoneal injection of inhibitor of autophagy 3-methyladenine at 15 mg/kg, 30 minutes before LPS injection. The anti-CXCL16 group was given 20 mg/kg of CXCL16 monoclonal antibody 30 minutes before the LPS injection. RESULTS In the 3-MA Group, the level of histological analysis, lung wet/dry ratio, total protein of BAL (bronchoalveolar lavage fluid) and TNF-a level were higher than the L group (p<0.05), the level of autophagy was lower than the L group (p<0.05), and the level of CXCL16 was higher than the L group (p<0.05). In the anti-CXCL16 group, the level of histological analysis, lung wet/dry ratio, BAL protein, and TNF-α level were declined compared to the L group (p<0.05), but there was no statistically significant difference in expression of CXCL16 detected by ELISA between the anti-CXCL16 group and the L group (p>0.05). CONCLUSIONS Autophagy played a protective role in ALI induced by LPS in mice. Autophagy could regulate the level of CXCL16. The chemokine CXCL16 could exacerbate ALI.