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Query: UMLS:C0027627 (metastases)
 103,950 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tumorigenesis involves not only tumor cells that become transformed but also the peritumoral stroma which reacts inducing inflammatory and angiogenic responses. Angiogenesis, the formation of new capillaries from preexisting vessels, is an absolute requirement for tumor growth and metastasis, and it can be induced and modulated by a wide variety of soluble factors. During angiogenesis, quiescent endothelial cells are activated and they initiate migration by degrading the basement membranes through the action of specific proteases, in particular of matrix metalloproteinases (MMPs). Among these, the membrane type 1-matrix metalloproteinase (MT1-MMP) has been identified as a key player during the angiogenic response. In this review, we will summarize the role of MT1-MMP in angiogenesis and the regulatory mechanisms of this protease in endothelial cells. Since our recent findings have suggested that MT1-MMP is not universally required for angiogenesis, we hypothesize that the regulation and participation of MT1-MMP in angiogenesis may depend on the nature of the angiogenic stimulus. Experiments aimed at testing this hypothesis have shown that similarly to the chemokine stromal cell-derived factor-1 (SDF-1)/CXCL12, lipopolysaccharide (LPS) seems to induce the formation of capillary tubes by human or mouse endothelial cells (ECs) in an MT1-MMP-independent manner. The implications of these findings in the potential use of MT1-MMP inhibitors in cancer therapy are discussed.
Cancer Metastasis Rev 2006 Mar
PMID:MT1-MMP: universal or particular player in angiogenesis? 1668 May 74

Nasopharyngeal carcinoma (NPC) is an epithelial cancer that metastasizes predictably to cervical lymph nodes or distant organs. To assess whether the chemokine receptors of NPC cells play important roles in metastasis and are associated with radiotherapy history, the significance of various chemokine receptors (CCR1-10, CXCR1-6, XCR1, and CX3CR1) in NPC cell lines (TW01, TW04, HONE1, BM1, and AS1) and 52 NPC tumour biopsies from 48 patients with NPC was evaluated by mRNA and cytometric analyses, chemotaxis and actin polymerization assays, and immunohistochemical staining. Quantitative real-time reverse transcription-polymerase chain reaction revealed substantial expression of CCR7, CCR9, CXCR4, and CXCR6 mRNA in all the NPC cell lines. Of these, however, only CCR7, CXCR4, and CXCR6 were functional in NPC cells. Negative immunoreactivity for CCR7, CXCR4, and CXCR6 was demonstrated in almost all nasopharyngeal (NP) specimens from patients with primary NPC (n = 12) and in those with regional metastatic NPC (n = 15). However, expression of two or three of these chemokine receptors was demonstrated in NP specimens from patients with liver metastasis. Strong positivity was demonstrated for all three of these chemokine receptors in almost all of the regional and distant metastasis specimens. Significant differences in the expression of CCR7, CXCR4, and CXCR6 were found between primary tumours and metastases (p < 0.001, p < 0.001, and p < 0.002, respectively). This observation was further confirmed by laser capture microdissection of freshly frozen tumours from primary (n = 5) and metastatic (n = 8) NPC sites (p = 0.04, 0.03, and 0.03 for CCR7, CXCR4, and CXCR6, respectively). Finally, significant differences in CXCR4 expression were demonstrated between de novo and post-radiotherapy groups (1/22 vs. 5/8; p < 0.003). It appears reasonable to conclude, therefore, that CCR7, CXCR4, and CXCR6 are expressed and active in human NPC metastases, while CXCR4 expression is associated with radiotherapy history.
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PMID:Chemokine receptor expression profiles in nasopharyngeal carcinoma and their association with metastasis and radiotherapy. 1695 98

Tumor development and progression are multifactorial processes, regulated by a large variety of intrinsic and microenvironmental factors. A key role in cancer is played by members of the chemokine superfamily. Chemokines and their receptors are expressed by tumor cells and by host cells, in primary tumors and in specific metastatic loci. The effects of chemokines on tumorigenesis are diverse: While some members of the superfamily significantly support this process, others inhibit fundamental events required for tumor establishment and metastasis. The current review describes the multifaceted roles of chemokines in malignancy, addressing four major aspects of their activities: (1) inducing leukocyte infiltration to tumors and regulating immune functions, with emphasis on tumor-associated macrophages (and the chemokines CCL2, CCL5), T cells (and the chemokines CXCL9, CXCL10) and dendritic cells (and the chemokines CCL19, CCL20, CCL21); (2) directing the homing of tumor cells to specific metastatic sites (the CXCL12-CXCR4 axis); (3) regulating angiogenic processes (mainly the ELR(+)-CXC and non-ELR-CXC chemokines); (4) acting directly on the tumor cells to control their malignancy-related functions. Together, these different chemokine functions establish a net of interactions between the tumor cells and their microenvironment, and partly dictate the fate of the malignancy cascade.
Cancer Metastasis Rev 2006 Sep
PMID:The multifaceted roles of chemokines in malignancy. 1701 63

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.
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PMID:Expression and function of the chemokine receptor CCR7 in thyroid carcinomas. 1706 6

Renal cell carcinoma (RCC) is characterized by organ-specific metastases. The chemokine stromal derived factor-1 (SDF-1/CXCL12) and its receptor CXCR4 have been suggested to regulate organ-specific metastasis in various other cancers. On this basis, we hypothesized that the biological axis of CXCL12 via interaction with its receptor, CXCR4, is a major mechanism for RCC metastasis. We demonstrated that CXCR4 was significantly expressed on circulating cytokeratin+ RCC cells from patients with known metastatic RCC. We detected up-regulation of CXCR4 mRNA and protein levels on a human RCC cell line by either knockdown of the von Hippel-Lindau (VHL) tumor suppressor protein, or incubating the cells under hypoxic conditions. The enhanced CXCR4 expression was mediated through the interaction of the Hypoxia Inducible Factor-1alpha (HIF-1alpha) with the promoter region of the CXCR4 gene. Furthermore, the expression of CXCR4 on human RCC directly correlated with their metastatic ability in vivo in both heterotopic and orthotopic SCID mouse models of human RCC. Neutralization of CXCL12 in SCID mice abrogated metastasis of RCC to target organs expressing high levels of CXCL12; without altering tumor cell proliferation, apoptosis, or tumor-associated angiogenesis. Therefore, our data suggest that the CXCL12/CXCR4 biological axis plays an important role in regulating the organ-specific metastasis of RCC.
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PMID:Stromal derived factor-1 (SDF-1/CXCL12) and CXCR4 in renal cell carcinoma metastasis. 1708 23

Multiple myeloma (MM) is a plasma cell malignancy, characterized by the localization of the MM cells in the bone marrow (BM), where they proliferate and induce osteolysis. The MM cells first need to home or migrate to the BM to receive necessary survival signals. In this work, we studied the role of CCR1 and CCR5, two known chemokine receptors, in both chemotaxis and osteolysis in the experimental 5TMM mouse model. A CCR1-specific (BX471) and a CCR5-specific (TAK779) antagonist were used to identify the function of both receptors. We could detect by RT-PCR and flow cytometric analyses the expression of both CCR1 and CCR5 on the cells and their major ligand, macrophage inflammatory protein 1alpha (MIP1alpha) could be detected by ELISA. In vitro migration assays showed that MIP1alpha induced a 2-fold increase in migration of 5TMM cells, which could only be blocked by TAK779. In vivo homing kinetics showed a 30% inhibition in BM homing when 5TMM cells were pre-treated with TAK779. We found, in vitro, that both inhibitors were able to reduce osteoclastogenesis and osteoclastic resorption. In vivo end-term treatment of 5T2MM mice with BX471 resulted in a reduction of the osteolytic lesions by 40%; while TAK779 treatment led to a 20% decrease in lesions. Furthermore, assessment of the microvessel density demonstrated a role for both receptors in MM induced angiogenesis. These data demonstrate the differential role of CCR1 and CCR5 in MM chemotaxis and MM associated osteolysis and angiogenesis.
Clin Exp Metastasis 2006
PMID:Role of CCR1 and CCR5 in homing and growth of multiple myeloma and in the development of osteolytic lesions: a study in the 5TMM model. 1708 56

The mechanisms that cause tumors such as melanomas to metastasize into peripheral lymphatic capillaries are poorly defined. Non-mutually-exclusive mechanisms are lymphatic endothelial cell (LEC) chemotaxis and proliferation in response to tumor cells (chemotaxis-lymphangiogenesis hypothesis) or LECs may secrete chemotactic agents that attract cancer cells (chemotactic metastasis hypothesis). Using migration assays, we found evidence supporting both hypotheses. Conditioned medium (CM) from metastatic malignant melanoma (MMM) cell lines attracted LEC migration, consistent with the lymphangiogenesis hypothesis. Conversely, CM from mixed endothelial cells or LECs, but not blood endothelial cells, attracted MMM cells but not non-metastatic melanoma cells, consistent with the chemotactic metastasis hypothesis. MMM cell lines expressed CCR7 receptors for the lymphatic chemokine CCL21 and CCL21 neutralizing antibodies prevented MMM chemotaxis in vitro. To test for chemotactic metastasis in vivo tumor cells were xenotransplanted into nude mice approximately 1 cm from an injected LEC depot. Two different MMM grew directionally towards the LECs, whereas non-metastatic melanomas did not. These observations support the hypothesis that MMM cells grow towards regions of high LEC density owing to chemotactic LEC secretions, including CCL21. This chemotactic metastasis may contribute to the close association between metastasizing tumor cells and peri-tumor lymphatic density and promote lymphatic invasion.
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PMID:Chemokine-mediated migration of melanoma cells towards lymphatics--a mechanism contributing to metastasis. 1713 Aug 36

The paradigm of cancer development and metastasis is a comprehensive, complex series of events that ultimately reflects a coordinated interaction between the tumor cell and the microenvironment within which the tumor cell resides. Despite the realization that this relationship has changed the current paradigm of cancer research, the struggle continues to more completely understand the pathogenesis of the disease and the ability to appropriately identify and design novel targets for therapy. A particular area of research that has added a significant understanding to cancer metastasis is the role of chemokines and chemokine receptors. Here we review the current concepts of CCL2 (monocyte chemoattractant protein 1) and its role in tumor metastasis with particular interest to its role in the development of bone metastases.
Cancer Metastasis Rev 2006 Dec
PMID:CCL2 (Monocyte Chemoattractant Protein-1) in cancer bone metastases. 1716 Jul 12

Breast cancer cells preferentially spread to bone. Bone metastases are currently incurable and therefore better treatments need to be developed. Metastasis is an inefficient, multi-step process. Specific aspects of both breast cancer cells and the bone microenvironment contribute to the development of bone metastases. Breast cancers express chemokine receptors, integrins, cadherins, and bone-resorbing and bone-forming factors that contribute to the successful and preferential spread of tumor to bone. Bone is rich in growth factors and cell types that make it a hospitable environment for breast cancer growth. Once breast cancer cells enter the bone, a highly complex vicious cycle develops, in which breast cancer cells secrete factors that act on bone cells and other cells within the bone (stem cells, T cells, platelets, adipocytes, fibroblasts, and endothelial cells), causing them to secrete factors that act on adjacent cancer cells. The steps in the metastatic cascade and the vicious cycle within bone offer unique targets for adjuvant treatments to treat and cure bone metastases.
Cancer Metastasis Rev 2006 Dec
PMID:Molecular interactions between breast cancer cells and the bone microenvironment drive skeletal metastases. 1716 31

Tumor cells are known to adapt to and utilize existing physiological mechanisms to promote survival and metastasis. The role of the microenvironment in the establishment of a metastatic lesion has become increasingly important as several factors secreted by stromal cells regulate metastatic pattern in a variety of tumor types. Tumor cells interact with osteoblasts, osteoclasts and bone matrix to form a vicious cycle that is essential for successful metastases. Here we review the current concepts regarding the role of an important chemokine/chemokine receptor (SDF-1 or CXCL12/CXCR4) pathway in tumor development and metastasis. CXCL12 secretion by stromal cells is known to attract cancer cells via stimulation of the CXCR4 receptor that is up regulated by tumor cells. CXCL12/CXCR4 activation regulates the pattern of metastatic spread with organs expressing high levels of CXCL12 developing secondary tumors (i.e., the bone marrow compartment). CXCL12 has a wide range of effects in regards to tumor development but the primary role of CXCL12 appears to be the mobilization of hematopoietic stem cells and the establishment of the cancer stem-like cell niche where high levels of CXCL12 recruit a highly tumorigenic population of tumor cells and promotes cell survival, proliferation, angiogenesis, and metastasis.
Cancer Metastasis Rev 2006 Dec
PMID:The pivotal role of CXCL12 (SDF-1)/CXCR4 axis in bone metastasis. 1716 32


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