10663

CXCR6

chemokine (C-X-C motif) receptor 6;CXCR6;chemokine (C-X-C motif) receptor 6

C-X-C chemokine receptor type 6|CDw186|CXC-R6|CXCR-6|G protein-coupled receptor|G-protein coupled receptor STRL33|G-protein coupled receptor bonzo

3p21

protein-coding

Recent evidence suggests that the chemokine axis of CXC chemokine ligand-12 and its receptor CXC chemokine receptor-4 (CXCL12/CXCR4) is highly expressed in gynecological tumors and the axis of CXC chemokine ligand-16 and CXC chemokine receptor-6 (CXCL16/CXCR6) is overexpressed in inflammation-associated tumors. This study aimed to determine the relationship between CXCL12/CXCR4, CXCL16/CXCR6 and ovarian carcinomas clinicopathologic features and prognosis. Accordingly, the expression of these proteins in ovarian tissues was detected by tissue microarray and immunohistochemistry. The expressions of CXCL12/CXCR4 and CXCL16/CXCR6 were significantly higher in epithelial ovarian carcinomas than in normal epithelial ovarian tissues or benign epithelial ovarian tumors. The expression of chemokines CXCL12 and CXCL16 were positively correlated with their receptors CXCR4 and CXCR6 in ovarian carcinoma, respectively (r = 0.300, P < 0.05; r = 0.395, P < 0.05). Moreover, the expression of CXCL12 was related to the occurrence of ascites (Chi(2) = 4.76, P < 0.05), the expression of CXCR4 was significantly related to lymph node metastasis (Chi(2) = 4.37, P < 0.05), the expression of CXCR6 was significantly related to lymph node metastasis (Chi(2) = 7.43, P < 0.05) and histological type (Chi(2) = 33.48, P < 0.05). In univariate analysis, the expression of CXCR4 and CXCL16 significantly correlated with reduced median survival (Chi(2) = 4.67, P < 0.05; Chi(2) = 4.48, P < 0.05). Therefore, we conclude that the chemokine axes CXCL12/CXCR4 and CXCL16/CXCR6 may play important roles in the growth, proliferation, invasion, and metastasis of epithelial ovarian carcinoma.

In spite of the clinical importance of prostate cancer (PCa) bone metastasis, the precise mechanisms for the directed migration of malignant cells remain unclear. In the present study, the expression of CXCR6 in human PCa and benign prostatic hyperplasia samples, and the expression of CXCL16 in human osseous tissues were determined by immunohistochemistry. It was found that the level of CXCR6 protein expression was elevated in human malignant prostate tumors, and CXCL16 was expressed positively by human osteocytes in vivo. The in vitro experiments further confirmed that the PCa cell lines PC3 and LNCap expressed CXCR6 at both the mRNA and protein levels, and exogenous CXCL16 has the potential to stimulate the invasion of PC3 and LNCap. To further elucidate the role of the CXCL16-CXCR6 axis in PCa progression, we compared the expression of CXCR6 and CXCR4 in human PCa tissues and the effects of CXCL16 and CXCL12 on the in vitro invasion of PC3 and LNCap cells. It was shown that CXCR6 and CXCR4 proteins were coexpressed and elevated in human PCa samples, and CXCL16 and CXCL12 promoted the invasion of PC3 and LNCap via their respective receptors. Furthermore, in contrast to CXCL12, which enhanced the activity of matrix metalloproteinase (MMP) 9 and MMP2 in PC3 and LNCap, CXCL16 ligation resulted in stronger MMP9 and MMP2 activity in LNCap but not in PC3. Our results suggest that besides CXCL12/CXCR4, CXCL16/CXCR6 might be another important factor involved in PCa bone metastasis.