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Prediction of lymph node metastasis in colorectal carcinoma by expressionof chemokine receptor CCR7.

Chemokine receptors are known to regulate homing of lymphocytes into secondary lymphoid organs and may also be involved in the lymphatic spread of solid tumors. Therefore, the assessment of chemokine receptor expression on colorectal carcinomas could potentially improve the prediction of lymph node spread. This is of great importance for the selection of patients for local therapy without the need for concomitant lymphatic dissection. Currently, only 5% of all patients can be selected for this desirable treatment option by established prognosticators. In a retrospective study, expression levels of the chemokine receptors CCR7, CXCR4 and CXCR5 were determined by immunohistochemistry on paraffin-embedded specimens of 99 colorectal carcinomas, which were curatively operated on, comprising all stages of the disease. Receptor expressions (absent vs. positive) from the overall tumor (OT) and from the invasion front (IF) including further prognosticators were correlated with lymph node status by uni- and multivariate analysis. Data were also correlated with synchronous distant metastases and overall survival. Median follow-up was 64 months. In univariate analysis, lymph node status correlated significantly with lymphovascular invasion, the expression of CCR7 IF, CCR7 OT, CXCR4 IF and CXCR4 OT, as well as pT category. Multivariate analysis revealed a significant correlation of lymph node status with lymphovascular invasion and CCR7 IF expression level. Most interestingly, CCR7 IF expression was significantly linked to decreased survival. CCR7 plays an important role in the mechanism of lymph node spread in colorectal carcinoma. Evaluation of the chemokine receptor expression profile seems to be appropriate to improve the selection of patients suited for local treatment and might constitute targets for nonsurgical therapy.

Adult↗

The chemokine receptor CCR7 is expressed on epithelium of non-inflamed gastric mucosa, Helicobacter pylori gastritis, gastric carcinoma and its precursor lesions and up-regulated by H. pylori.

CCR7 chemokine-receptor expression on tumour cells of gastric carcinoma has been associated with lymph-node metastasis and is thought to play an important role in metastasis. However, so far it is unknown whether CCR7 is newly up-regulated on gastric carcinoma or already expressed in non-neoplastic gastric epithelium. Therefore, epithelial CCR7 expression was investigated in the process of gastric carcinogenesis: non-inflamed mucosa --Helicobacter pylori gastritis -- intestinal metaplasia/dysplasia -- gastric carcinoma. CCR7 was expressed by gastric epithelium in non-inflamed gastric mucosa (n = 5), H. pylori gastritis (n = 17), intestinal metaplasia (n = 10), dysplasia (n = 3) and on tumour cells in 20 of 24 patients with gastric carcinoma (13/14 intestinal-type; 7/10 diffuse-type) as tested by immunohistochemistry. As CCR7 expression by gastric epithelium was significantly stronger in H. pylori gastritis than in non-infected mucosa, the influence of H. pylori on CCR7 receptor expression of gastric epithelial cells was investigated by fluorescence activated cell sorter analysis. H. pylori strains up-regulated the CCR7 chemokine-receptor in CCR7-positive cell lines. No difference in CCR7 up-regulation between cag(+) and cag(-)H. pylori strains was found. Epithelial CCR7 up-regulation by H. pylori may alter the metastatic fate of gastric carcinoma. Additionally, CCR7 expression not only on gastric carcinoma, but also on non-neoplastic gastric epithelium, suggests a novel biological function.

Carcinoma↗

The chemokine receptor CCR7 and alpha4 integrin are important for migration of chronic lymphocytic leukemia cells into lymph nodes.

Malignant lymphocyte migration into lymph nodes is an important aspect of chronic lymphocytic leukemia (CLL), yet little is known about the processes involved. Here we demonstrate that CLL cells migrate across vascular endothelium in response to at least 3 chemokines, namely, CCL21, CCL19, and CXCL12. Moreover, transendothelial cell migration (TEM) in response to CCL21 and CCL19 was significantly higher for the malignant B cells of patients who had clinical lymph node involvement as compared with those of patients lacking such organomegaly. Furthermore, the expression of CCR7, the receptor for both CCL21 and CCL19, correlated with clinical lymphadenopathy, and blocking of CCR7 inhibited CLL cell TEM. By using immunohistochemistry we demonstrated that CCL21 and CCL19, but not CXCL12, are located in high endothelial venules and are, therefore, in an appropriate location to induce TEM. Regarding the adhesion receptors involved in TEM, alpha4 (most likely in association with beta1) and alphaLbeta2 were shown to be important in CLL cell TEM in vitro, but only the level of alpha4 expression correlated with the presence of clinical lymphadenopathy. The present studies are the first to shed light on the factors determining CLL cell entry into nodes and define the phenotype of circulating malignant cells likely to determine the pattern of lymph node enlargement in the disease.

Aged↗

The T cell chemokine receptor CCR7 is internalized on stimulation with ELC, but not with SLC.

ELC and SLC are potent agonists for CCR7, a receptor of up-most importance for the regulation of the homing and traffic of lymphocytes into and within secondary lymphoid tissues. We have studied the effects of both chemokines on receptor re-distribution in T lymphocytes and other CCR7-bearing cells by flow cytometry and by assessing receptor mediated functions. In this paper we show that ELC and SLC differ fundamentally in the ability to induce the internalization of their receptor. ELC induced a rapid time- and concentration-dependent internalization of CCR7 and markedly decreased the ability of CCR7-bearing cells to respond to a second stimulation. No receptor internalization, by contrast, was observed on stimulation with SLC. Receptors that were internalized on stimulation with ELC were re-expressed when the cells were washed. Re-expression of receptors and consequent re-activation of the cells was prevented in the presence of ELC, but was not affected in the presence of SLC. These findings could explain how T lymphocytes that enter lymphoid tissues in response to SLC produced by high-endothelial venules can subsequently migrate in response to SLC and ELC expressed within the T cell areas.

Calcium↗

Expression and function of the chemokine receptor CCR7 in thyroid carcinomas.

The chemokine receptor CCR7 plays a critical role in lymphocyte and dendritic cell trafficking into and within lymph nodes, the preferential metastatic site for papillary (PTC) and medullary (MTC) thyroid carcinomas. In order to determine a possible role for CCR7 in mediating the metastatic behaviour of thyroid carcinomas, we analysed its expression in normal and tumoral thyroid tissues of different histotypes and studied the in vitro effects of its activation by the CCR7 ligand, CCL21. Using real-time quantitative-PCR, we observed that CCR7 expression was higher in PTCs and MTCs than in follicular and poorly differentiated thyroid carcinomas. CCR7 expression was ninefold higher in classic compared with follicular variants of PTCs, and its expression in MTCs was significantly correlated with lymph node metastases. Immunohistochemical staining for CCR7 showed protein expression in neoplastic thyroid cells, with higher intensity in PTCs, MTCs and their lymph node metastases (LNMs). We further showed that CCL21 stimulation of a CCR7-expressing thyroid tumour cell line (TPC-1) promotes cell proliferation and migration, and the chemotactic effect of CCL21 in these cells involves actin polymerization, increased beta1-integrin expression and increased matrix metalloproteinase secretion. Taken together, our results demonstrate that CCR7 activation on thyroid carcinoma cells by CCL21 - a chemokine abundantly expressed in lymph nodes - favours tissue invasion and cell proliferation, and therefore may promote thyroid carcinoma growth and LNM.

Actins↗

6-C-kine (SLC), a lymphocyte adhesion-triggering chemokine expressed by high endothelium, is an agonist for the MIP-3beta receptor CCR7.

The beta chemokine known as 6-C-kine, secondary lymphoid-tissue chemokine (SLC), TCA4, or Exodus-2 (herein referred to as 6CK/SLC) can trigger rapid integrin-dependent arrest of lymphocytes rolling under physiological shear and is highly expressed by high endothelial venules, specialized vessels involved in lymphocyte homing from the blood into lymph nodes and Peyer's patches. We show that 6CK/SLC is an agonist for the lymphocyte chemoattractant receptor, CCR7 (EBI-1, BLR-2), previously described as a receptor for the related beta chemokine MIP-3beta (ELC or Exodus-3). Moreover, 6CK/SLC and MIP-3beta attract the same major populations of circulating lymphocytes, including naive and memory T cells > B cells (but not natural killer cells); desensitization to MIP-3beta inhibits lymphocyte chemotaxis to 6CK/SLC but not to the alpha chemokine SDF-1 (stromal cell-derived factor); and 6CK/SLC competes for MIP-3beta binding to resting mouse lymphocytes. The findings suggest that the majority of circulating lymphocytes respond to 6CK/SLC and MIP-3beta in large part through their common receptor CCR7 and that these molecules may be important mediators of physiological lymphocyte recirculation in vivo.

Animals↗

Expression of chemokine receptor CCR7 is associated with lymph node metastasis of gastric carcinoma.

The interactions of chemokine receptor CCR7 and its ligands are essential for migration of lymphocytes and dendritic cells to lymph nodes. In this study, we found that 4 of 6 (67%) gastric carcinoma cell lines tested expressed functional CCR7 for the chemokine CCL21/6Ckine, as demonstrated by calcium mobilization and actin polymerization assays. Moreover, we also showed that signaling through CCR7 induced chemotactic and invasive responses in CCR7-positive gastric carcinoma cells. In clinical samples, immunohistochemical assay showed that CCR7-positive carcinoma cells were detected in 42 of 64 (66%) cases and a significant difference in both lymph node metastasis (P < 0.001) and lymphatic invasion (P < 0.001) between CCR7-positive and -negative cases. Patients with CCR7-positive tumors had a significantly poorer prognosis than those with CCR7-negative tumors (P < 0.05). Stepwise regression analysis revealed that the most important factor related to lymph node metastasis was the expression of CCR7. These results indicated that CCR7 and its ligands interaction is associated with preferential lymph node metastasis of gastric carcinoma.

Actins↗

Binding of the chemokine SLC/CCL21 to its receptor CCR7 increases adhesive properties of human mesangial cells.

BACKGROUND: Adherence of human mesangial cells to the surrounding matrix contributes to glomerular homeostasis and is important for the maintenance of glomerular architecture and function in normal adult human kidney. The expression of chemokines and corresponding chemokine receptors on adjacent intrinsic renal cells indicates a novel chemokine/chemokine receptor function on nonimmune cells important for glomerular homeostasis. A constitutive expression of the chemokine SLC/CCL21 on human podocytes and of its corresponding receptor CCR7 on mesangial cells was shown before. SLC/CCL21 has a positive effect on proliferation and migration of mesangial cells and leads to increased cell survival in Fas-induced apoptosis. In leukocytes chemokines mediate integrin-dependent firm adhesion. Therefore, we examined the influence of chemokine receptor CCR7 activation by SLC/CCL21 on adhesive properties of human mesangial cells to matrix molecules. METHODS: Adhesion assays, mechanical detachment assays, and evaluation of integrin activation by integrin-linked kinase activity were performed. Changes in the cytoskeletal F-actin were illustrated by phalloidin immunofluorescence staining. RESULTS: SLC/CCL21 stimulation enhanced adhesiveness to fibronectin in a time- and concentration-dependent manner. SLC/CCL21 also increased the firmness of mesangial cells adhesion as judged by detachment assays. Furthermore activation of integrin-linked kinase occurred with SLC/CCL21 addition to mesangial cells, resulting in increased phosphorylation of glycogen synthase kinase-3 (GSK-3) and protein kinase B (PKB/Akt). Exposure of mesangial cells to SLC/CCL21 also resulted in F-actin rearrangements with membrane ruffling and extensions leading to bridging between mesangial cells. CONCLUSION: Activation of CCR7 on mesangial cells by SLC/CCL21 enhances the degree and firmness of cell adhesion and increases cell spreading and the formation of cell-cell contacts. This includes integrin-linked kinase activation and F-actin rearrangements. Thus, local chemokine generation and chemokine receptor expression on mesangial cells may play an important role in the maintenance of glomerular homeostasis and in local remodeling processes.

Actins↗

The chemokine receptor CCR7 controls lymph node-dependent cytotoxic T cell priming in alloimmune responses.

The chemokine receptor CCR7 and its ligands regulate migration and colocalization of T cells and mature dendritic cells to and within secondary lymphoid organs. The requirement of CCR7 in efficient priming of allospecific cytotoxic CD8(+) T cells is poorly characterized. Here, we demonstrate a role for CCR7 in the initiation of an alloimmune response and in the development of transplant rejection. Remarkably, in a model of acute allogeneic tumor rejection, CCR7(-/-) mice completely failed to reject subcutaneously injected MHC class I mismatched tumor cells and cytotoxic activity of allospecific T cells was severely compromised. When solid tumors derived from wild-type mice were transplanted, recipient CCR7(-/-) mice were capable of rejecting the allografts. In contrast, tumor allografts transplanted from CCR7(-/-) donors onto CCR7(-/-) recipients showed allograft survival up to 28 days, suggesting a critical function of CCR7 on donor-type passenger leukocytes in the initiation of cytotoxic CD8(+) T cell responses. In a heterotopic heart transplantation model CCR7 deficiency resulted in significantly prolonged but not indefinite allograft survival. Additional prolongation of graft survival was observed when hearts from CCR7(-/-) mice were used as donor organs. Our results define a key role for CCR7 in allogeneic T cell priming within the context of draining lymph nodes.

Adoptive Transfer↗

Circulating clonal CLA(+) and CD4(+) T cells in Sezary syndrome express the skin-homing chemokine receptors CCR4 and CCR10 as well as the lymph node-homing chemokine receptor CCR7.

BACKGROUND: Adhesion molecules and chemokine receptors are involved in tissue-specific homing of T cells to the skin and play an important role in the pathophysiology of cutaneous lymphoma. It has recently been reported that the chemokine CCL27 expressed by keratinocytes attracts lymphocytes bearing the chemokine receptor CCR10. OBJECTIVES: To investigate the expression of CCR4, CCR7 and CCR10 on skin-homing CLA(+) and CD4(+) T cells in the peripheral blood of patients with Sezary syndrome (SS), a rare leukaemic variant of cutaneous T-cell lymphoma. METHODS: Lymphocytes from five patients with SS, six patients with mycosis fungoides and four healthy volunteers were isolated and analysed using flow cytometry. Additionally, the T-cell receptor (TCR)-Vbeta CDR3 regions were cloned and sequenced in two patients. RESULTS: We found that CCR4 is expressed on almost all CLA(+) and CD4(+) memory T cells. Using monoclonal antibodies specific for single TCR-Vbeta chains we identified malignant T cells in four patients with SS. Importantly, we found that most but not all malignant Sezary cells expressed the skin-homing chemokine receptor CCR10. Additionally, we found that a significant proportion of these cells also expressed the lymph node-homing chemokine receptor CCR7. CONCLUSIONS: Our results support the concept that chemokine receptors play an important role in the pathophysiology of SS and suggest that the malignant clone may represent an expansion of skin-homing cutaneous 'central' memory T cells in the peripheral blood of these patients.

Adult↗

Expression of vascular endothelial growth factor C and chemokine receptor CCR7 in gastric carcinoma and their values in predicting lymph node metastasis.

AIM: To study the expression of vascular endothelial growth factor C (VEGF-C) and chemokine receptor CCR7 in gastric carcinoma and to investigate their associations with lymph node metastasis of gastric carcinoma and their values in predicting lymph node metastasis. METHODS: The expression of VEGF-C and CCR7 in gastric carcinoma tissues obtained from 118 patients who underwent curative gastrectomy was examined by immunohistochemistry. Among these patients, 39 patients underwent multi-slice spiral CT (MSCT) examination. RESULTS: VEGF-C and CCR7 were positively expressed in 52.5 and 53.4% of patients. VEGF-C expression was more frequently found in tumors with lymph node metastasis than those without it (P<0.001). VEGF-C expression was also closely related to lymphatic invasion (P<0.001), vascular invasion (P<0.01), and TNM stage (P<0.001). However, there was no significant correlation between VEGF-C expression and age at surgery, gender, tumor size, tumor location, Lauren classification, and depth of invasion. CCR7 expression was significantly higher in patients with lymph node metastasis compared with those without lymph node metastasis (P<0.001) and was also associated with tumor size (P<0.01), depth of invasion (P<0.001), lymphatic invasion (P<0.001), and TNM stage (P<0.001). However, the presence of CCR7 had no correlation to age at surgery, gender, tumor location, Lauren classification, and vascular invasion. Among the 39 patients who underwent MSCT examination, only CCR7 expression was related to lymph node metastasis determined by MSCT (P<0.05). In the current retrospective study, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of VEGF-C and CCR7 expression in the diagnosis of lymph node metastasis for patients with gastric carcinoma were 73.8%, 70.2%, 72.6%, 71.4% and 72.0%, and 82.0%, 77.2%, 79.4%, 80.0% and 79.7%, respectively. After subdivision according to the combination of VEGF-C and CCR7 expression, receiver operating characteristic (ROC) analysis showed that the accuracy of the combined examination of VEGF-C and CCR7 expression in predicting lymph node metastasis was relatively high (area under ROC curve [Az]=0.83). CONCLUSION: The expression of VEGF-C and CCR7 is related to lymph node metastasis of gastric carcinoma and both of them may become new targets for the treatment of gastric carcinoma. Furthermore, the combined examination of VEGF-C and CCR7 expression in endoscopic biopsy specimens may be useful in predicting lymph node metastasis of gastric carcinoma and deciding the extent of surgical lymph node resection.

Carcinoma↗

Chemokine receptor CCR7 enhances intrahepatic and lymphatic dissemination of human hepatocellular cancer.

Despite many pathophysiological analyses, the process of tumor dissemination of hepatocellular carcinoma (HCC) remains vague. In diverse tumor entities, expression of the chemokine receptor, CCR7, has been linked to tumor dissemination and poor prognosis. Therefore, we evaluated, whether CCR7 exerts similar effects in human HCC. CCR7 expression analysis was performed in vitro on human hepatoma cell lines (Huh7, Hep3B, wt HepG2, p53 dominant negative transfected HepG2). In addition, CCR7 expression was evaluated in 39 patients with hepatocellular cancer and correlated with both, tumor and patients characteristics. Human hepatocellular carcinoma samples and hepatoma cell lines displayed variable intensities of CCR7 expression. In patients, CCR7 expression was significantly associated with progressed local tumors (P = 0.02) and lymphatic metastasis (P = 0.02). Strong expression of CCR7 promotes intrahepatic and lymphatic HCC dissemination.

Aged↗

Differential requirements for the chemokine receptor CCR7 in T cell activation during Listeria monocytogenes infection.

Effective priming of T cell responses depends on cognate interactions between naive T cells and professional antigen-presenting cells (APCs). This contact is the result of highly coordinated migration processes, in which the chemokine receptor CCR7 and its ligands, CCL19 and CCL21, play a central role. We used the murine Listeria monocytogenes infection model to characterize the role of the CCR7/CCR7 ligand system in the generation of T cell responses during bacterial infection. We demonstrate that efficient priming of naive major histocompatibility complex (MHC) class Ia-restricted CD8+ T cells requires CCR7. In contrast, MHC class Ib-restricted CD8+ T cells and MHC class II-restricted CD4+ T cells seem to be less dependent on CCR7; memory T cell responses are independent of CCR7. Infection experiments with bone marrow chimeras or mice reconstituted with purified T cell populations indicate that CCR7 has to be expressed on CD8+ T cells and professional APCs to promote efficient MHC class Ia-restricted T cell priming. Thus, different T cell subtypes and maturation stages have discrete requirements for CCR7.

Animals↗

A ligand for the chemokine receptor CCR7 can influence the homeostatic proliferation of CD4 T cells and progression of autoimmunity.

Homeostasis of T cell numbers in the periphery implies an ability of lymphocytes to sense cell numbers. Although the mechanisms are unknown, we find that the chemokine CCL21 (also known as TCA4, SLC, 6Ckine), a ligand for the chemokine receptor CCR7, can regulate homeostasis of CD4 (but not CD8) T cells. In the absence of CCR7 ligands, transferred CD4 T cells failed to expand in lymphopenic hosts, whereas in the presence of CCL21 overexpression, homeostatic CD4 T cell proliferation occurred even in nonlymphopenic recipients. Ag-specific CD4 T cells transferred into Ag-expressing mice proliferated and induced autoimmunity only in lymphopenic recipients. Pancreatic expression of CCL21 was sufficient to replace the requirement for lymphopenia in the progression of autoimmune disease. These results suggest that CD4 T cells use local concentrations of CCR7 ligands as an index of T cell steady state numbers and that homeostatic expansion of the T cell population may be a contributing factor in the development of autoimmune disease.

Adoptive Transfer↗

Chemokine receptor CCR7 guides T cell exit from peripheral tissues and entry into afferent lymphatics.

T cell circulation between peripheral tissues and the lymphoid compartment is critical for immunosurveillance and host defense. However, the factors that determine whether T cells remain in peripheral tissue or return to the circulation are undefined. Here we demonstrate that the chemokine receptor CCR7 is a critical signal that determines T cell exit from peripheral tissue. Both CCR7(-) and CCR7(+) effector T cells entered mouse asthmatic lung and while CCR7(-) T cells accumulated, CCR7(+) T cells continued to migrate into afferent lymph. Delivery of both CCR7(+) and CCR7(-) T cells directly into the airways showed that only CCR7(+) T cells exited the lung and entered draining lymph nodes. Our study establishes a molecular basis for T cell exit from peripheral tissues.

Animals↗

Gene expression changes in foam cells and the role of chemokine receptor CCR7 during atherosclerosis regression in ApoE-deficient mice.

Atherosclerosis regression is an important clinical goal. In previous studies of regression in mice, the rapid loss of plaque foam cells was explained by emigration to lymph nodes, a process reminiscent of dendritic cells. In the present study, plaque-containing arterial segments from apoE-/- mice were transplanted into WT recipient normolipidemic mice or apoE-/- mice. Three days after transplant, in the WT regression environment, plaque size decreased by approximately 40%, and foam cell content by approximately 75%. In contrast, both parameters increased in apoE-/- recipients. Foam cells were isolated by laser capture microdissection. In WT recipients, there were 3- to 6-fold increases in foam cells of mRNA for liver X receptor alpha and cholesterol efflux factors ABCA1 and SR-BI. Although liver X receptor alpha was induced, there was no detectable expression of its putative activator, peroxisome proliferator-activated receptor gamma. Expression levels of VCAM or MCP-1 were reduced to 25% of levels in pretransplant or apoE-/- recipient samples, but there was induction at the mRNA and protein levels of chemokine receptor CCR7, an essential factor for dendritic cell migration. Remarkably, when CCR7 function was abrogated in vivo by treatment of WT recipients with antibodies to CCR7 ligands CCL19 and CCL21, lesion size and foam cell content were substantially preserved. In summary, in foam cells during atherosclerosis regression, there is induction of CCR7 and a requirement for its function. Taken with the other gene expression data, these results in vivo point to complex relationships among the immune system, nuclear hormone receptors, and inflammation during regression.

ATP Binding Cassette Transporter 1↗

Chemokine receptor CCR7 required for T lymphocyte exit from peripheral tissues.

Lymphocytes travel throughout the body to carry out immune surveillance and participate in inflammatory reactions. Their path takes them from blood through tissues into lymph and back to blood. Molecules that control lymphocyte recruitment into extralymphoid tissues are well characterized, but exit is assumed to be random. Here, we showed that lymphocyte emigration from the skin was regulated and was sensitive to pertussis toxin. CD4(+) lymphocytes emigrated more efficiently than CD8(+) or B lymphocytes. T lymphocytes in the afferent lymph expressed functional chemokine receptor CCR7, and CCR7 was required for T lymphocyte exit from the skin. The regulated expression of CCR7 by tissue T lymphocytes may control their exit, acting with recruitment mechanisms to regulate lymphocyte transit and accumulation during immune surveillance and inflammation.

Animals↗

Molecular cloning and chromosomal assignment to SSC12p13-->p11 of swine chemokine receptor CCR7.

We cloned a gene encoding the swine chemokine (C-C motif) receptor 7 (CCR7) and clarified its genomic structure and chromosomal assignment. The ORF and deduced amino-acid sequence were highly conserved with human and mouse CCR7. The swine CCR7 gene was mapped to SSC12p13-->p11 by FISH analysis. Stimulation of swine peripheral blood mononuclear cells by IL-12 and IL-18, considered potent inducers of Th1 cells from analyses in humans and mice, downregulated the expression of CCR7. This is the first report of the molecular cloning, chromosomal assignment and characterization of a chemokine receptor in swine.

Amino Acid Sequence↗