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1: Arthritis and rheumatism, 2010 Apr 19, 210(1)
Expression and function of CXCL16 in a novel model of gout.

[Abstract]OBJECTIVE:: To better define the activity of soluble CXCL16 to recruit polymorphonuclear cells (PMNs) in vivo, we developed a novel animal model of gout pathology. We tested CXCL16 to recruit PMNs in a human normal synovial tissue (NL ST) severe combined immunodeficient (SCID) mouse chimera injected intragraft with gouty SF. METHODS:: For in vitro studies, we utilized the modified Boyden chemotaxis system to identify CXCL16 as an active recruitment factor for PMNs. Cell migration could be reduced by neutralizing gouty SF CXCL16 activity. For in vivo analysis, fluorescently dye-tagged PMNs were injected i.v., while a simultaneous injection of diluted gouty SF containing CXCL16 was administered intragraft. We similarly inhibited the receptor for CXCL16, CXCR6, by incubating PMNs with neutralizing CXCR6 antibodies and examined PMN recruitment to gouty tissues in the SCID mouse chimera system. RESULTS:: CXCL16 is highly elevated in gouty SF and PMNs migrate to CXCL16 in vitro. NL ST SCID mouse chimeras injected intragraft with gouty SF depleted of CXCL16 during PMN transfer showed a significant 50% reduction of PMN recruitment to engrafted tissue compared to grafts administered sham depleted gouty SF. Similar findings were achieved when incubating PMNs with neutralizing anti-CXCR6 antibody before injection into chimeras administered gouty SF. CONCLUSION:: Overall, this study outlines the effectiveness of the human SCID mouse chimera system as a viable animal model for gout, identifying a primary function of CXCL16 as a significant mediator of in vivo PMN recruitment to gouty SF.

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2: Dermato-endocrinology, 2009 Mar, 1(2)
Overexpression of CXCL16 in lesional psoriatic skin.

[Abstract]BACKGROUND: Psoriasis is characterized as an autoimmune disease resulting in an exaggerated innate immune response. The CXC-chemokine ligand 16 (CXCL16) is described to function as an adhesion molecule, a scavenger receptor or as a soluble molecule it acts as a chemoattractant. CXCL16 has been reported to be expressed in a variety of inflammatory diseases. However, no information has been reported in the literature about the expression of CXCL16 in psoriatic skin. PURPOSE: The present study was designed to analyze the expression and localization of CXCL16 in human psoriatic skin tissues. RESULTS: In normal skin, cytpoplasmic expression of CXCL16 was increased in keratinocytes of upper epidermal cell layers as compared to the lower epidermal cell layers. In lesional psoriatic skin, CXCL16 immunoreactivity was increased in the cytoplasm of keratinocytes of lower epidermal layer kerartinocytes as compared to the normal epidermis. Cytoplasmic CXCL16 expression was increased in the capillary endothelial cells of psoriatic dermis as compared to capillary endothelial cells of the normal dermis. Notably, almost all inflammatory cells in the dermis were negative for CXCL16. MATERIALS AND METHODS: Ten paraffinized specimens of human lesional psoriatic skin and five paraffinized specimens of normal skin were studied using an immunohistochemical streptavidinperoxidase technique. CONCLUSION: We here report for the first time alterations in the immunohistochemical staining pattern of CXCL16 in lesional psoriatic skin compared to the normal skin. These results suggest that CXCL16 may play a role in the pathogenesis of psoriasis.

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3: European journal of cancer (Oxford, England : 1990), 2009 Feb, 45(3)
Tumoural CXCL16 expression is a novel prognostic marker of longer survival times in renal cell cancer patients.

[Abstract]The aim of our study was to analyse the expression of CXCL16, ADAM10 and CXCR6 in renal cell carcinoma (RCC) tissue and to correlate the expression pattern with clinicopathologic data, including patient survival. Furthermore, we investigated CXCL16, ADAM10 and CXCR6 expressions by FACS, immunofluorescence and ELISA analysis in renal carcinoma cell lines. Our immunohistochemical analysis on tissue microarray of renal cancer samples of 104 patients revealed that ADAM10 correlated significantly with tumour stage, pathological nodal status, M status and lymphangiosis carcinomatosa. CXCL16, CXCR6 and ADAM10 were significantly increased in papillary carcinomas. Importantly, high levels of CXCL16 expression in renal cancer tissue correlated with better survival of patients, and CXCL16 correlated inversely to the tumour stage. In addition, inhibition of CXCL16 induced the migration of renal cancer cells assuming an anti-migratory function of transmembrane CXCL16. Taken together, our data demonstrate that downregulation of CXCL16 plays an important role in renal cancer development and progression, and that CXCL16 in RCC is an independent prognostic marker for better patient survival.

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4: Clinical immunology (Orlando, Fla.), 2008 Nov, 129(2)
CXCR6-CXCL16 interaction in the pathogenesis of Juvenile Idiopathic Arthritis.

[Abstract]In order to evaluate the role of CXCR6/CXCL16 in driving lymphocyte migration into inflamed joints of children with oligoarticular Juvenile Idiopathic Arthritis (JIA) we analysed CXCR6 expression and functional capability in lymphocytes from synovial fluid (SF) by flow cytometry, by real-time polymerase chain reaction (RT-PCR) and migration assays. Furthermore, CXCR6 and CXCL16 expression in synovial tissue (ST) was analysed by immunohistochemistry. T cells isolated from SF of patients with JIA expressed CXCR6 which was functionally active as shown by chemotactic assays. The same cells expressed CXCR3 and it exerted a migratory activity in response to CXCL10. CXCL16 and CXCR6 were intensively expressed on the synovium cells, respectively on macrophages, synoviocytes and endothelial cells and on lymphocytes, synoviocytes and endothelial cells. Taken together, these data suggest that CXCR6 and CXCR3 act coordinately with respective ligands and are involved in the pathophysiology of JIA-associated inflammatory processes.

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5: Journal of immunology (Baltimore, Md. : 1950), 2008 Sep 1, 181(5)
Radiation-induced CXCL16 release by breast cancer cells attracts effector T cells.

[Abstract]Recruitment of effector T cells to inflamed peripheral tissues is regulated by chemokines and their receptors, but the factors regulating recruitment to tumors remain largely undefined. Ionizing radiation (IR) therapy is a common treatment modality for breast and other cancers. Used as a cytocidal agent for proliferating cancer cells, IR in combination with immunotherapy has been shown to promote immune-mediated tumor destruction in preclinical studies. In this study we demonstrate that IR markedly enhanced the secretion by mouse and human breast cancer cells of CXCL16, a chemokine that binds to CXCR6 on Th1 and activated CD8 effector T cells, and plays an important role in their recruitment to sites of inflammation. Using a poorly immunogenic mouse model of breast cancer, we found that irradiation increased the migration of CD8(+)CXCR6(+) activated T cells to tumors in vitro and in vivo. CXCR6-deficient mice showed reduced infiltration of tumors by activated CD8 T cells and impaired tumor regression following treatment with local IR to the tumor and Abs blocking the negative regulator of T cell activation, CTLA-4. These results provide the first evidence that IR can induce the secretion by cancer cells of proinflammatory chemotactic factors that recruit antitumor effector T cells. The ability of IR to convert tumors into "inflamed" peripheral tissues could be exploited to overcome obstacles at the effector phase of the antitumor immune response and improve the therapeutic efficacy of immunotherapy.

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6: International journal of oncology, 2008 Aug, 33(2)
Expression and potential function of the CXC chemokine CXCL16 in pancreatic ductal adenocarcinoma.

[Abstract]CXC chemokines have a major influence on the angiogenesis, growth and metastatic potential of pancreatic ductal adenocarcinoma. CXCL16 is a unique transmembrane CXC chemokine, which is shed by members of the disintegrins and metalloproteases (ADAMs), in particular by ADAM10 and ADAM17. In our study, we evaluated expression and potential function of CXCL16 and its receptor CXCR6. CXCL16 and the receptor CXCR6 are upregulated in pancreatic ductal adenocarcinoma (PDAC) and chronic pancreatitis tissues in contrast to normal pancreatic tissues at the mRNA and protein levels. In 85 and 100% of the investigated samples, tumor cells showed positive immuno-staining for CXCL16 and CXCR6, respectively; furthermore, tubular complexes of chronic pancreatitis and the invasive front of PDAC were immunopositive for CXCL16 and CXCR6. Stimulation of PDAC cells with proinflammatory cytokines increased CXCL16 protein levels, whereas silencing of ADAM10 with siRNA transfection led to a decrease in CXCL16 protein levels in cell culture supernatants. No effects on cell viability were notable after incubation of cancer cells with CXCL16. However, CXCL16 markedly increased invasiveness of PDAC cells. Clinically, 82.5% of PDAC patients had higher CXCL16 serum values than the highest value seen in healthy donors. SELDI-TOF-MS analysis confirmed the upregulation of CXCL16 in sera of PDAC patients. In conclusion, CXCL16 in both transmembrane and soluble forms, and its receptor CXCR6, seem to play an important role in the pathobiology of pancreatic cancer and might be potential markers for pancreatic cancer diagnosis and a target for multimodal therapy concepts in the future.