Tumor-associated macrophages promote the metastasis of ovarian carcinoma cells by enhancing CXCL16/CXCR6 expression.

This study investigated the underlying mechanism by which C-X-C motif chemokine ligand 16 (CXCL16)/C-X-C motif chemokine receptor 6 (CXCR6) signaling is activated by tumor-associated macrophages and assists in regulating the metastasis of ovarian carcinoma. Specimens of ovarian carcinoma tissue and adjacent tissue were collected from 20 ovarian carcinoma patients. Human THP-1 cells were induced to differentiate into macrophages, which were then co-cultured with SKOV3 cells and low concentrations of tumor necrosis factor-α (TNF-α) to simulate the inflammatory microenvironment of ovarian carcinoma. Additionally, small interfering RNA (siRNA) targeting CXCR6 was transfected into SKOV3 cells; after which, the levels of nuclear factor kappa B p65 (NF-κB p65) protein and phosphorylated PI3K and Akt were measured. The migration and invasion abilities of the SKOV3 cells were also tested. The levels of TNF-α, interluekin-6 (IL-6), NF-κB p65, CXCL16, and CXCR6 expression in the ovarian carcinoma tissues were higher than those in the precancerous tissues. CXCR6 expression was positively correlated with TNF-α, IL-6, and CXCL16 expression. Co-culture of SKOV3 cells with macrophages significantly promoted CXCL16, CXCR6, NF-κB, and p65 expression by the SKOV3 cells, increased their levels of phosphorylated PI3K and Akt, and increased the migration and invasion abilities of SKOV3 cells. Silencing of CXCR6 or blocking the PI3K/Akt signal pathway markedly attenuated the expression of NF-κB p65 and phosphorylation of PI3K and Akt, as well as the migration and invasion abilities of SKOV3 cells. These findings demonstrate that macrophages can promote the migration and invasion of ovarian carcinoma cells by affecting the CXCL16/CXCR6 pathway.

Downregulation of MicroRNA eca-mir-128 in Seminal Exosomes and Enhanced Expression of CXCL16 in the Stallion Reproductive Tract Are Associated with Long-Term Persistence of Equine Arteritis Virus.

Equine arteritis virus (EAV) can establish long-term persistent infection in the reproductive tract of stallions and is shed in the semen. Previous studies showed that long-term persistence is associated with a specific allele of the CXCL16 gene (CXCL16S) and that persistent infection is maintained despite the presence of a local inflammatory and humoral and mucosal antibody responses. In this study, we demonstrated that equine seminal exosomes (SEs) are enriched in a small subset of microRNAs (miRNAs). Most importantly, we demonstrated that long-term EAV persistence is associated with the downregulation of an SE-associated miRNA (eca-mir-128) and with an enhanced expression of CXCL16 in the reproductive tract, a putative target of eca-mir-128. The findings presented here suggest that SE eca-mir-128 is implicated in the regulation of the CXCL16/CXCR6 axis in the reproductive tract of persistently infected stallions, a chemokine axis strongly implicated in EAV persistence. This is a novel finding and warrants further investigation to identify its specific mechanism in modulating the CXCL16/CXCR6 axis in the reproductive tract of the EAV long-term carrier stallion.IMPORTANCE Equine arteritis virus (EAV) has the ability to establish long-term persistent infection in the stallion reproductive tract and to be shed in semen, which jeopardizes its worldwide control. Currently, the molecular mechanisms of viral persistence are being unraveled, and these are essential for the development of effective therapeutics to eliminate persistent infection. Recently, it has been determined that long-term persistence is associated with a specific allele of the CXCL16 gene (CXCL16S) and is maintained despite induction of local inflammatory, humoral, and mucosal antibody responses. This study demonstrated that long-term persistence is associated with the downregulation of seminal exosome miRNA eca-mir-128 and enhanced expression of its putative target, CXCL16, in the reproductive tract. For the first time, this study suggests complex interactions between eca-mir-128 and cellular elements at the site of EAV persistence and implicates this miRNA in the regulation of the CXCL16/CXCR6 axis in the reproductive tract during long-term persistence.

High expression of CXC chemokine receptor 6 associates with poor prognosis in patients with clear cell renal cell carcinoma.

PURPOSE: Accumulating evidence indicates that CXC chemokine receptor 6 (CXCR6) has a crucial role in cancer development and progression, however, its role in clear cell renal cell carcinoma (ccRCC) remains obscure. The aim of this study is to investigate the prognostic value of CXCR6 expression in patients with ccRCC following surgery. MATERIALS AND METHODS: This study retrospectively included 239 patients with ccRCC who underwent nephrectomy and had paraffin tissue available at a single center. CXCR6 expression in tumor tissue was evaluated by immunohistochemistry and its associations with overall survival (OS) and recurrence-free survival (RFS) were investigated. RESULTS: A total of 47.3% tumors were considered as high expression of CXCR6, which was significantly associated with the male sex (P = 0.003) and high Fuhrman grade (P<0.001). A high expression of CXCR6 indicated a reduced OS (P<0.001) and RFS (P = 0.007). Multivariate analysis demonstrated that CXCR6 expression was an independent prognostic factor of OS (hazard ratio = 2.604; 95% CI: 1.338-5.068; P = 0.005) and RFS (hazard ratio = 1.957; 95% CI: 1.065-3.595; P = 0.031). Subgroup analysis found that CXCR6 expression could differentiate survival risks among patients with high-risk disease. Moreover, a nomogram integrating CXCR6 expression and traditional clinical and pathologic features was established and predicted postsurgical recurrence-risk well at 3- and 5-year. CONCLUSIONS: The expression of CXCR6 in tumor tissue may serve as a potential prognostic biomarker to refine clinical prognosis prediction combined with traditional clinical and pathological analysis for patients with ccRCC after surgery.