The chemotactic cytokines called chemokines are a superfamily of small secreted cytokines that were initially characterized through their ability to prompt the migration of leukocytes. Attention has been focused on the chemokine receptors expressed on cancer cells because cancer cell migration and metastasis show similarities to leukocyte trafficking. CXC chemokine receptor 4 (CXCR4) was first investigated as a chemokine receptor that is associated with lung metastasis of breast cancers. Recently, CXCR4 was reported to be a key molecule in the formation of peritoneal carcinomatosis in gastric cancer. In the present review, we highlight current knowledge about the role of CXCR4 in cancer metastases. In contrast to chemokine receptors expressed on cancer cells, little is known about the roles of cancer cell-derived chemokines. Cancer tissue consists of both cancer cells and various stromal cells, and leukocytes that infiltrate into cancer are of particular importance in cancer progression. Although colorectal cancer invasion is regulated by the chemokine CCL9-induced infiltration of immature myeloid cells into cancer, high-level expression of cancer cell-derived chemokine CXCL16 increases infiltrating CD8 + and CD4 + T cells into cancer tissues, and correlates with a good prognosis. We discuss the conflicting biological effects of cancer cell-derived chemokines on cancer progression, using CCL9 and CXCL16 as examples. (Cancer Sci 2007; 98: 1652-1658) C hemokines are a family of small (8-14 kDa), mostly basic, heparin-binding cytokines that primarily induce directed migration of various types of leukocytes through interactions with a group of seven transmembrane G protein-coupled receptors (GPCR). GPCR mediate biological effects such as cell migration. That is, normal rapid leukocyte trafficking is controlled strictly by chemokines and their receptors.(1,2) To date, over 50 chemokines and 20 chemokine receptors have been identified, and are grouped into four categories (C, CC, CXC, and CX3C) based on the location of the main cysteine residues near the N termini of these proteins.Leukocyte trafficking and, to a lesser degree, cancer metastasis have regular rules called organ selectivity. The cancer metastatic process can be divided into several migration steps. First, cancer cells are released from the primary cancer to the surrounding tissues, enter the vascular or lymphatic circulation, and are transported through it. Then, the cells become arrested in the capillary bed of a distant organ and extravasate from the circulation to organ parenchyma. However, although cancer migration from the primary site to distant organs is essential to establish metastasis, we know very little about the molecular mechanisms that regulate cancer cell migration.It is now thought that chemokines play a significant role in organ-selective cancer metastasis, because cancer cell migration and metastasis share many similarities with leukocyte trafficking. (3,4) Several chemokine receptors are regarded as molecules related to cancer metast...

CXCL16 is a new member of the chemokine superfamily, which exists in a transmembrane as well as a soluble form. Its receptor CXCR6 is detected on CD4 + T cells, CD8 + T cells, and natural killer T cells. Here, we report a significant correlation of CXCL16 expression by tumor cells with the infiltration of T cells and prognosis in colorectal cancer (CRC). We first found that CXCL16 expression was consistently up-regulated more in tumor tissues than in normal mucosa derived from the same CRC patients. Four human CRC cell lines also expressed CXCL16 mRNA and secreted soluble CXCL16. We next examined the expression of CXCL16 and infiltration of lymphocytes in CRC specimens (n = 58) by immunohistochemistry. CRC patients with high levels of CXCL16 expression (n = 43) had higher levels of CD4 + and CD8 + tumor-infiltrating lymphocytes (TIL; P < 0.01) than those with low levels of CXCL16 expression (n = 15). Furthermore, the high CXCL16 expression group showed significantly better prognosis than the low CXCL16 expression group (P < 0.05). Collectively, our data suggest that the expression of CXCL16 by tumor cells enhances the recruitment of TILs, thereby bringing about a better prognosis in CRC. Thus, CXCL16 is a new prognostic biomarker and may be useful for the development of a more effective therapeutic strategy for CRC. [Cancer Res 2007;67(10):4725-31]

No abstract

This study aimed to investigate the shear bond strength of an autopolymerizing resin to a nylon denture base polymer (Lucitone FRS: LT) subjected to different surface treatments, and the results thereof compared with a heat-polymerizing resin and a polycarbonate polymer. Specimens were divided into five groups according to the surface treatment method: polishing (#600), sandblasting, adhesive primer application (resin primer), sandblasting + adhesive primer application, and tribochemical coating (Rocatec system). Following which, specimens were subjected to a shear bond strength test and Si concentrations were measured using an electron probe microanalyzer (EPMA). On shear bond strength, that of LT with tribochemical coating was significantly higher than the other groups. On EPMA results, the surface of LT with tribochemical coating was found to be covered with a silica film. Therefore, findings in this study indicated that silica-coating by Rocatec system was effective in improving the bond strength of nylon denture base polymer to autopolymerizing repair resin.

No abstract