6347

CCL2

chemokine (C-C motif) ligand 2;CCL2;chemokine (C-C motif) ligand 2

C-C motif chemokine 2|monocyte chemoattractant protein 1|monocyte chemoattractant protein-1|monocyte chemotactic and activating factor|monocyte chemotactic protein 1|monocyte secretory protein JE|small inducible cytokine A2 (monocyte chemotactic protein 1

17q11.2-q12

protein-coding

Macrophages, which are abundant in the tumour microenvironment, enhance malignancy. At metastatic sites, a distinct population of metastasis-associated macrophages promotes the extravasation, seeding and persistent growth of tumour cells. Here we define the origin of these macrophages by showing that Gr1-positive inflammatory monocytes are preferentially recruited to pulmonary metastases but not to primary mammary tumours in mice. This process also occurs for human inflammatory monocytes in pulmonary metastases of human breast cancer cells. The recruitment of these inflammatory monocytes, which express CCR2 (the receptor for chemokine CCL2), as well as the subsequent recruitment of metastasis-associated macrophages and their interaction with metastasizing tumour cells, is dependent on CCL2 synthesized by both the tumour and the stroma. Inhibition of CCL2-CCR2 signalling blocks the recruitment of inflammatory monocytes, inhibits metastasis in vivo and prolongs the survival of tumour-bearing mice. Depletion of tumour-cell-derived CCL2 also inhibits metastatic seeding. Inflammatory monocytes promote the extravasation of tumour cells in a process that requires monocyte-derived vascular endothelial growth factor. CCL2 expression and macrophage infiltration are correlated with poor prognosis and metastatic disease in human breast cancer. Our data provide the mechanistic link between these two clinical associations and indicate new therapeutic targets for treating metastatic breast cancer.

PURPOSE: This study aimed to identify novel biological markers for the prediction of colorectal cancer liver metastasis. EXPERIMENTAL DESIGN: We established two models that mimicked the interactions between colorectal tumor cells and the liver microenvironment. From these models we established subcell lines that had an enhanced ability to metastasize to the liver. Genes that related to hepatic metastasis were screened by microarray. The candidate markers were tested by immunohistochemistry, and their predictive accuracy was assessed by the cross-validation method and an independent test set. RESULTS: Highly metastatic colon cancer cell sublines SW1116p21 and SW1116v3 were established from the tumor cell-microenvironment interaction models. Seven of the up-regulated genes in the sublines were selected as candidate markers for predicting metastatic potential. A total of 245 colorectal cancer samples were divided into a training set containing 117 cases and a test set containing 128 cases. In the training set, immunohistochemical analysis showed CCL2 and SNCG expression was higher in the hepatic metastasis group than in the nonmetastasis group, and was correlated with poor survival. Logistic regression analysis revealed that CCL2 and SNCG levels in primary tumors, serum carcinoembryonic antigen level, and lymph node metastasis status were the only significant (P < 0.05) parameters for detecting liver metastasis. In leave-one-out-cross-validation, the two markers, when combined with clinicopathologic features, resulted in 90.5% sensitivity and 90.7% specificity for hepatic metastasis detection. In an independent test set, the combination achieved 87.5% sensitivity and 82% specificity for predicting the future hepatic metastasis of colorectal cancer. CONCLUSION: Our results suggest that these models are able to mimic the interactions between colorectal cancer cells and the liver microenvironment, and may represent a promising strategy to identify metastasis-related genes. CCL2 and SNCG, combined with clinicopathologic features, may be used as accurate predictors of liver metastasis in colorectal cancer.

expression and activity of CC motif ligand 2 (CCL2) is down-regulated by curcumin, the active phytochemical ingredient of turmeric (Curcuma longa), a dietary supplement often self-prescribed to promote prostate health. CCL2 is a potent chemotactic factor of prostate cancer (PCa) with important roles in development of bone metastasis. The relationship between CCL2 and curcumin, however, has not been studied in PCa. Adhesion, invasion and motility of PC-3 cells were measured in response to exposure to curcumin (30 microM; 18 h), CCL2 (100 ng/ml; 18 h) or PMA (100 ng/ml; 18 h). CCL2 mRNA expression and protein secretion levels were measured by real-time PCR and ELISA respectively. Curcumin significantly blocked CCL2 induced adhesion, invasion and motility. Curcumin also significantly suppressed the mRNA expression and secreted CCL2 protein levels. The addition of PMA, a protein kinase C (PKC) activator, blocked the effects of curcumin, leading to an increase in CCL2 expression as well as an increase in PC-3 cell adhesion, invasion and motility. The introduction of a PKC inhibitor, however, blocked the effects of CCL2. We also found that curcumin, CCL2 and PMA, in part, function through the differential regulation of the proteolytic protein matrix metalloproteinase (MMP)-9. These data indicate a potential mechanism; by which curcumin can block the chemotactic effects of CCL2 on PCa. Curcumin exerts potential anti-metastatic effects in bone-derived PCa cells by blocking CCL2 mediated actions on invasion, adhesion and motility, in part through differential regulation of PKC and MMP-9 signaling.

Macrophages, which are abundant in the tumour microenvironment, enhance malignancy. At metastatic sites, a distinct population of metastasis-associated macrophages promotes the extravasation, seeding and persistent growth of tumour cells. Here we define the origin of these macrophages by showing that Gr1-positive inflammatory monocytes are preferentially recruited to pulmonary metastases but not to primary mammary tumours in mice. This process also occurs for human inflammatory monocytes in pulmonary metastases of human breast cancer cells. The recruitment of these inflammatory monocytes, which express CCR2 (the receptor for chemokine CCL2), as well as the subsequent recruitment of metastasis-associated macrophages and their interaction with metastasizing tumour cells, is dependent on CCL2 synthesized by both the tumour and the stroma. Inhibition of CCL2-CCR2 signalling blocks the recruitment of inflammatory monocytes, inhibits metastasis in vivo and prolongs the survival of tumour-bearing mice. Depletion of tumour-cell-derived CCL2 also inhibits metastatic seeding. Inflammatory monocytes promote the extravasation of tumour cells in a process that requires monocyte-derived vascular endothelial growth factor. CCL2 expression and macrophage infiltration are correlated with poor prognosis and metastatic disease in human breast cancer. Our data provide the mechanistic link between these two clinical associations and indicate new therapeutic targets for treating metastatic breast cancer.

PURPOSE: We herein examined whether the single nucleotide polymorphism (SNP) at -2518 of the MCP-1 gene promoter region influences clinical outcomes among nasopharyngeal carcinoma (NPC) patients. EXPERIMENTAL DESIGN: The study population consisted of 411 NPC patients without metastasis at diagnosis. All patients were treated at the Chang Gung Memorial Hospital from March 1994 to November 2004. The MCP-1 SNP-2518 genotype of each patient was determined by TaqMan genotyping kit. Statistical analyses were conducted to compare disease-specific survival (DSS), progression-free survival (PFS), local recurrence-free survival (LRFS), and distant metastasis-free survival (DMFS) of patients according to genotype. MCP-1 expression in tumor biopsies was examined by immunohistochemistry. RESULTS: Among 411 NPC patients, carriers of AA and AG genotypes were prone to distant metastasis than that of GG genotype (hazard ratio, 2.21; P = 0.017, and hazard ratio, 2.23; P = 0.005, for AA and AG genotype, respectively) after initial radiotherapy. No genotype-specific significant difference was found in DSS, PFS, and LRFS. Furthermore, immunohistochemistry revealed that MCP-1 expression level was higher in NPC tumor cells from GG carriers compared with those from AA and AG carriers. CONCLUSIONS: MCP-1 SNP-2518 may be a valuable genetic marker for assessing the risk of developing distant metastasis after the radiotherapy in NPC patients. Carriers of A allele may require more aggressive chemotherapy implicating a potential marker for personalized medicine. We speculate that a regulatory SNP may be associated with the distant metastasis of NPC. Validation studies are warranted.

PURPOSE: Carcinoma-associated fibroblasts (CAFs) in tumor stroma play an important role in tumor progression and have been associated with a poor prognosis in oral squamous cell carcinoma (OSCC). However, how CAFs influence OSCC malignancy and whether normalizing CAFs inhibits cancer progression remain unclear. EXPERIMENTAL DESIGN: The relationship between the expression of Galectin-1 (Gal-1) and alpha-smooth muscle actin (alpha-SMA, a CAF marker) in OSCC patient samples and primary cultured CAFs was examined by quantitative real-time PCR, Western blotting, and immunofluorescence. To examine the effect of Gal-1 on CAF activation and CAF-mediated tumor invasion and migration in vitro, Gal-1 expression was knocked down by small hairpin RNA. Finally, cancer cells and CAFs were coimplanted into SCID mice to evaluate the effect of Gal-1 on CAF-modulated tumor progression in vivo. RESULTS: Gal-1 expression is positively associated with alpha-SMA in the stroma of OSCC specimens. Gal-1 knockdown decreases activated CAF characteristics, resulting in a decrease in alpha-SMA expression and extracellular matrix protein production. Notably, blocking Gal-1 expression significantly inhibits CAF-conditioned medium-induced tumor cell migration and invasion, possibly by reducing the production of monocyte chemotactic protein-1 (MCP-1/CCL2). MCP-1 induces the migration of OSCC cells by binding to the receptor CCR2; adding an MCP-1 antibody to CAF-conditioned medium that inhibits the interaction between MCP-1 and CCR2 abolishes migration. Finally, we found that Gal-1 knockdown in CAFs significantly reduces CAF-augmented tumor growth and metastasis in vivo. CONCLUSIONS: Our findings demonstrate that Gal-1 regulates CAF activation and indicate that targeting Gal-1 in CAFs inhibits OSCC metastasis by modulating MCP-1 expression.

Monocyte chemoattractant protein 1 (CCL2) is a recently identified prominent regulator of prostate cancer growth and metastasis. The purpose of this study was to investigate the mechanistic role of CCL2 in prostate cancer growth in bone. The present study found that CCL2 was up-regulated in osteoblasts (3-fold by PC-3 and 2-fold by VCaP conditioned medium) and endothelial cells (2-fold by PC-3 and VCaP conditioned medium). Parathyroid hormone-related protein (PTHrP) treatment of osteoblastic cells up-regulated CCL2 and was blocked by a PTHrP antagonist, suggesting that prostate cancer-derived PTHrP plays an important role in elevation of osteoblast-derived CCL2. CCL2 indirectly increased blood vessel formation in endothelial cells through vascular endothelial growth factor-A, which was up-regulated 2-fold with administration of CCL2 in prostate cancer cells. In vivo, anti-CCL2 treatment suppressed tumor growth in bone. The decreased tumor burden was associated with decreased bone resorption (serum TRAP5b levels were decreased by 50-60% in anti-CCL2-treated animals from VCaP or PC-3 cell osseous lesions) and microvessel density was decreased by 70% in anti-CCL2-treated animals with bone lesions from VCaP cells. These data suggest that a destructive cascade is driven by tumor cell-derived, PTHrP-mediated induction of CCL2, which facilitates tumor growth via enhanced osteoclastic and endothelial cell activity in bone marrow. Taken together, CCL2 mediates the interaction between tumor-derived factors and host-derived chemokines acting in cooperation to promote skeletal metastasis.

CC chemokine ligand 2 (CCL2, also known as monocyte chemoattractant protein-1) has been demonstrated to recruit monocytes to tumor sites. Monocytes are capable of being differentiated into tumor-associated macrophages (TAMs) and osteoclasts (OCs). TAMs have been shown to promote tumor growth in several cancer types. Osteoclasts have also been known to play an important role in cancer bone metastasis. To investigate the effects of CCL2 on tumorigenesis and its potential effects on bone metastasis of human prostate cancer, CCL2 was overexpressed into a luciferase-tagged human prostate cancer cell line PC-3. In vitro, the conditioned medium of CCL2 overexpressing PC-3luc cells (PC-3(lucCCL2)) was a potent chemoattractant for mouse monocytes in comparison to a conditioned medium from PC-3(lucMock). In addition, CCL2 overexpression increased the growth of transplanted xenografts and increased the accumulation of macrophages in vivo. In a tumor dissemination model, PC-3(lucCCL2) enhanced the growth of bone metastasis, which was associated with more functional OCs. Neutralizing antibodies targeting both human and mouse CCL2 inhibited the growth of PC-3(luc), which was accompanied by a decrease in macrophage recruitment to the tumor. These findings suggest that CCL2 increases tumor growth and bone metastasis through recruitment of macrophages and OCs to the tumor site.