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Query: UMLS:C0006142 (breast cancer)
 160,383 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Zoledronic acid (ZOL) is a nitrogen-containing bisphosphonate and its use in reducing osteoporosis and cancer-induced osteolysis is increasing. Recent findings indicated that ZOL has a direct effect on cancer cells. In this study, the effect of ZOL was examined on the aggressive MDA-MB-231 breast cancer cell line. ZOL induces an important inhibition of cell invasion at low concentrations (1 microM). This is not explained by modifications of proteases involved in cell invasiveness (matrix metalloproteinases and urokinase-type plasminogen activator), but by a disorganisation of actin cytoskeleton due to RhoA inhibition related to its defective prenylation as it was reversed by geranylgeraniol (GGOH) and mimicked by the Rho selective inhibitor C3 exoenzyme. In addition, ZOL inhibits the chemotactic effect induced by stromal cell-derived factor 1(SDF-1), a chemokine greatly involved in cancer metastasis to bone. This effect is related to both reduction of cell motility induced by RhoA inhibition and to a decreased expression of CXCR-4, the SDF-1 receptor. Finally, ZOL reduces Cox-2 expression and, consequently, the secretion of prostaglandins E2 (PGE2) in a RhoA-independent manner. This inhibition could contribute to bone protection in breast cancers because PGE2 stimulates osteoclast-mediated bone resorption. In summary, new insights in the mechanism of ZOL action on aggressive breast cancer cells are demonstrated and could explain its beneficial action in both the reduction of osteolysis and prevention of metastasis.
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PMID:New insights into the actions of bisphosphonate zoledronic acid in breast cancer cells by dual RhoA-dependent and -independent effects. 1277 33

The progression of breast cancer is affected by multiple cellular and microenvironmental components. The monocyte chemoattractant MCP-1, IL-6 and matrix metalloproteinases (MMP) were suggested to promote, each on its own, breast cancer progression. We recently demonstrated that the high-tumorigenicity phenotype of the DA3 and CSML murine mammary adenocarcinoma cells is correlated with a high expression of MCP-1, IL-6 and MMP. This raised the possibility that common intrinsic tumor-derived factors regulate the concordant expression of these 3 components. The aim of the present study was to gain insight into the mode by which the secretion of MCP-1, IL-6 and MMP from murine mammary adenocarcinoma cells is regulated. This was investigated in cellular clones established from a highly malignant variant of the DA3 tumor (DA3-high). We also determined the secretion of the antimalignancy chemokine IP-10 from these cells. The results indicate that the secretion levels of IL-6, MMP and IP-10 varied between the clones. In contrast, all the clones secreted uniformly high levels of MCP-1, suggesting that MCP-1 constitutes an important feature of the malignancy phenotype of mammary carcinoma. In most of the clones, elevated levels of 1 of the 3 promalignancy factors did not correlate with a high expression of the other 2 factors and vice versa. These findings indicate that the 3 promalignancy factors are not coregulated by a common intrinsic tumor-derived factor. Rather, these results suggest that the individual capacities of the different clones to secrete these factors are summed up in the high-malignancy DA3 parental tumor population, which secretes relatively high levels of MCP-1, IL-6 and MMP as compared to DA3 cells expressing a low-malignancy phenotype. In contrast to the lack of coordinated intrinsic regulation of MCP-1, IL-6 and MMP, it was found that recombinant TNFalpha, a product of tumor-associated macrophages contributing to breast cancer progression, upregulated the secretion of MCP-1, IL-6 and MMP from all the clones. These results suggest a key role for this microenvironmental, monocyte-derived cytokine in the coordinated regulation of these 3 molecules. Furthermore, additional results demonstrated that monocytic cell-derived TNFalpha upregulated MCP-1 secretion from the tumor cells and that MCP-1 in turn promoted the secretion of TNFalpha from monocytic cells. This may result in a positive feedback loop, whereby the tumor cells and the monocytic cells at tumor site promote each other's ability to express and secrete promalignancy factors. We next attempted to assess the contribution of the promalignancy factors MCP-1, IL-6 and MMP and of the antimalignancy factor IP-10 to mammary adenocarcinoma progression. To this end, a preliminary formula was developed in which the net balance between secretion levels of the promalignancy factors and that of the antimalignancy IP-10 chemokine from different clones was related to their in vivo tumorigenicity profile. This formula suggests that a balance between the secretion levels of these factors plays an important role in determining the malignancy phenotype of mammary carcinomas. In all, our findings demonstrate that the mammary tumor cell population is composed of a heterogeneous assortment of clones whose individual characteristics are averaged in the whole population. The malignancy potential of such tumors is thus determined, inter alia, by a combinatorial effect of several promalignancy and antimalignancy factors secreted from each of the clones comprising these tumors. Our results also suggest that the expression of such factors is determined by several nonmutually exclusive regulatory mechanisms.
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PMID:Progression of mouse mammary tumors: MCP-1-TNFalpha cross-regulatory pathway and clonal expression of promalignancy and antimalignancy factors. 1291 65

Interleukin 8 (IL-8) is a member of the alpha chemokine family of cytokines originally identified as a neutrophil chemoattractant. Recently, we reported that elevated levels of IL-8, but not parathyroid hormone-related protein (PTHrP), correlated with increased bone metastasis in a population of human breast cancer cells. We hypothesized that IL-8 expression by breast cancer cells would either indirectly influence osteoclastogenesis via nearby stromal cells or directly influence osteoclast differentiation and activity. In the present study, we investigated the role of IL-8 in the process of osteoclast formation and bone resorption, which is associated with metastatic breast cancer. The addition of recombinant human (rh) IL-8 (10 ng/ml) to cultures of stromal osteoblastic cells stimulated both RANKL mRNA expression and protein production, with no effect on the expression of osteoprotegerin. In addition, rhIL-8 also directly stimulated the differentiation of human peripheral blood mononuclear cells into bone-resorbing osteoclasts. In these cultures, IL-8 was able to stimulate human osteoclast formation even in the presence of excess (200 ng/ml) RANK-Fc. The effect of IL-8 on osteoclasts and their progenitors was associated with the cell surface expression of the IL-8-specific receptor (CXCR1) on the cells. These results demonstrate a direct effect of IL-8 on osteoclast differentiation and activity. Together, these data implicate IL-8 in the osteolysis associated with metastatic breast cancer.
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PMID:Interleukin-8 stimulation of osteoclastogenesis and bone resorption is a mechanism for the increased osteolysis of metastatic bone disease. 1291 97

Organ-specific metastasis is governed, in part, by interactions between chemokine receptors on cancer cells and matching chemokines in target organs. For example, malignant breast cancer cells express the chemokine receptor CXCR4 and commonly metastasize to organs that are an abundant source of the CXCR4-specific ligand stromal cell-derived factor-1alpha (ref. 1). It is still uncertain how an evolving tumour cell is reprogrammed to express CXCR4, thus implementing the tendency to metastasize to specific organs. Here we show that the von Hippel-Lindau tumour suppressor protein pVHL negatively regulates CXCR4 expression owing to its capacity to target hypoxia-inducible factor (HIF) for degradation under normoxic conditions. This process is suppressed under hypoxic conditions, resulting in HIF-dependent CXCR4 activation. An analysis of clear cell renal carcinoma that manifests mutation of the VHL gene in most cases revealed an association of strong CXCR4 expression with poor tumour-specific survival. These results suggest a mechanism for CXCR4 activation during tumour cell evolution and imply that VHL inactivation acquired by incipient tumour cells early in tumorigenesis confers not only a selective survival advantage but also the tendency to home to selected organs.
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PMID:Chemokine receptor CXCR4 downregulated by von Hippel-Lindau tumour suppressor pVHL. 1367 99

Estrogen contributes to the development of breast cancer through mechanisms that are not completely understood. Estrogen influences the function of immune effector cells, primarily through alterations in cytokine expression. Chemokines are proinflammatory cytokines that attract various immune cells to the site of tissue injury or inflammation, and activate many cell types, including T lymphocytes and monocytes. As an initial step toward ultimately determining whether regulation of chemokine expression and/or biological activity by estrogen could potentially be a contributing factor to the development and progression of mammary tumors, we evaluated the effect of estrogen on the expression of specific chemokines in murine mammary tissue. We also evaluated whether exposure of female mice to various chemokines could alter the growth of mammary tumors in the presence of estrogen. We report here that estrogen significantly decreases levels of the chemokines MIP-1alpha and MCP-1/JE in murine mammary tissue. Co-treatment with 4-hydroxytamoxifen partially reverses the suppressive effect of estrogen on MIP-1alpha levels. Estrogen increases the growth of CCL- 51 cell-based tumors in the mammary glands of female mice. Co-treatment with the chemokine MIP-1alpha or MCP- 1/JE substantially decreases the ability of estrogen to stimulate the formation of CCL-51 cell-based tumors. Our results show that estrogen might influence the bioactivity of specific chemokines through alteration of chemokine expression in mammary tissue, and further suggest that decreases in murine chemokines evoked by estrogen exposure could contribute to the promotion of mammary tumor growth.
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PMID:Estrogen decreases chemokine levels in murine mammary tissue: implications for the regulatory role of MIP-1 alpha and MCP-1/JE in mammary tumor formation. 1466 21

The leukocyte infiltrate of human and murine epithelial cancers is regulated by chemokine production in the tumor microenvironment. In this article, we tested the hypothesis that chemokine receptor antagonists may have anticancer activity by inhibiting this infiltrate. We first characterized CC chemokines, chemokine receptors, and the leukocyte infiltrate in the 410.4 murine model of breast cancer. We found that CCL5 (RANTES) was produced by the tumor cells, and its receptors, CCR1 and CCR5, were expressed by the leukocyte infiltrate. As Met-CCL5 is an antagonist of CCR1 and CCR5 with activity in models of inflammatory disease, we tested its activity against 410.4 tumors. After 5 weeks of daily treatment with Met-CCL5, the volume and weight of 410.4 tumors was significantly decreased compared with control-treated tumors. Met-CCL5 was also active against established tumors. The total cell number obtained after collagenase digestion was decreased in Met-CCL5-treated tumors as was the proportion of infiltrating macrophages. Furthermore, chemokine antagonist treatment increased stromal development and necrosis. Our results provide direct evidence that macrophages contribute to tumor development and are the first indication that chemokine receptor antagonists may provide novel strategies in cancer prevention and treatment.
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PMID:A chemokine receptor antagonist inhibits experimental breast tumor growth. 1467 97

The chemokine-CXCL12 and its receptor, CXCR4, have recently been shown to play an important role in regulating the directional migration of breast cancer cells to sites of metastasis. In the present study, we showed that CXCL12 enhanced the chemotaxis, chemoinvasion and adhesive properties of breast cancer cells; parameters that are critical for development of metastasis. We have also evaluated the signaling mechanisms that regulate CXCL12-induced and CXCR4-mediated breast cancer cell motility and invasion. These studies revealed that CXCL12 induces the tyrosine phosphorylation of focal adhesion kinase (FAK) at residues 397 and 577, and of RAFTK/Pyk2 at residues 402 and 579/580. The cytoskeletal proteins paxillin and Crk, as well as tyrosine phosphatase SHP2 and adaptor protein Cbl, were also phosphorylated. CXCL12 induced the activation of PI 3-kinase, and increased its association with Cbl and SHP2. PI 3-kinase, RAFTK/Pyk2 and tyrosine phosphatase inhibitors significantly blocked CXCL12-induced chemotaxis and chemoinvasion. The role of SHP2 and Cbl in CXCL12-induced chemotaxis and chemoinvasion in breast cancer cells was further defined by transiently overexpressing wild-type SHP2, wild-type Cbl, dominant-negative SHP2, Cbl mutants 70Z/3 and G306E or double transfectants of the Cbl and SHP2 constructs. We found a novel role of Cbl in CXCL12-induced chemotaxis, which may be mediated through the activation and formation of a multimeric complex comprised of Cbl, SHP2 and PI 3-kinase. We also observed the activation of matrix metalloproteinases 2 and 9 upon CXCL12 stimulation. These studies provide new information regarding signaling pathways that may regulate CXCL12-induced metastasis in breast cancer cells.
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PMID:Regulation of CXCR4-mediated chemotaxis and chemoinvasion of breast cancer cells. 1471 21

Chemokines are pro-inflammatory cytokines that function to attract immune cells to the sites of tissue inflammation, injury or infection. We have formulated the hypothesis that release of one chemokine can serve, in a local paracrine or endocrine fashion, to induce the release of other chemokines from neighboring mammary cells. We set out to investigate whether specific chemokines could promote the release of other chemokine members from mammary cells, and whether estrogen could serve to disrupt the release of these chemokines from mammary cells. We found that treatment with the chemokine IP-10 resulted in significant increases in the amount of MIP-1alpha and MCP-1/JE released from murine mammary cells. Estrogen co-treatment significantly blocked the ability of IP-10 to trigger the release of MIP-1alpha and MCP-1/JE. Suppressive effects of estrogen were reversed upon co-treatment with 4-hydroxytamoxifen. Estrogen treatment significantly decreased expression of proteins corresponding to the chemokine receptors CXCR3 and CCR5 on mammary cells. Exposure of female mice to IP-10 in vivo significantly decreased the ability of estrogen to support the growth of CCL-51-based tumors in mammary tissue. Our results suggest that exposure of mammary tissue to estrogen may decrease the release of local chemokines from mammary cells, potentially increasing the risk of tumor growth through decreased immune surveillance. Ongoing studies are investigating the possible mechanisms through which IP-10 stimulates the release of chemokines from mammary cells, and how the action of IP-10 may serve to decrease mammary tumor formation.
Breast Cancer Res Treat 2004 Apr
PMID:Estrogen disrupts chemokine-mediated chemokine release from mammary cells: implications for the interplay between estrogen and IP-10 in the regulation of mammary tumor formation. 1502 21

Recent evidence attributed important influence of chemokines and their receptors on motility, homing, and proliferation of cancer cells at specific metastatic sites. Here we report that the CXCL12 (SDF-1alpha) chemokine receptor CXCR4 is expressed in human ductal carcinoma in situ (DCIS) as well as in atypical ductal hyperplasia. CXCR4 was expressed in pure DCIS and DCIS with concurrent invasive disease. In 66% of the samples, atypical ductal hyperplasia was present, and > 92% exhibited positive CXCR4-staining. Expression of CXCR4 at this very early step of tumor development indicates a role of this receptor in providing a selective advantage to such cells on their way to metastasizing carcinomas. These results strengthen the ideas to target chemokine networks involved in tumor progression and metastatis as a therapeutic approach in malignant disease or as a chemoprevention strategy, blocking the transition from premalignancy to malignancy.
Breast Cancer Res Treat 2004 Apr
PMID:CXCR4 is expressed in ductal carcinoma in situ of the breast and in atypical ductal hyperplasia. 1502 22

The acquisition of a metastatic phenotype in breast epithelial cells is a progressive process, influenced by a large variety of cellular and soluble factors. Of these, members of the chemokine superfamily, such as CCL2, CCL5, CXCL8 and CXCL12 have been recently suggested to promote breast cancer progression. A pre-requisite for elucidation of the role of other chemokines in breast cancer progression is the characterization of chemokine and chemokine receptor expression by breast tumor cells. The present study focuses on CXCL10, a CXC chemokine that was recently suggested to have anti-malignant properties, and its corresponding receptor CXCR3. CXCR3 expression was detected in three human breast adenocarcinoma cell lines, MDA-MB-231, MCF-7 and T47D. CXCR3 expression was potently up-regulated by growing the cells under stress conditions, imposed by serum starvation. Unlike many other chemokine receptors, CXCR3 expression was not down-regulated by exposure to high concentrations (500ng/ml) of its ligand, CXCL10, but rather was promoted. CXCL10-induced up-regulation of CXCR3 expression in the three cell lines was inhibited by cycloheximide, indicating that de novo protein synthesis is required for this process. In addition to CXCR3, the secretion of CXCL10 was noted in the MDA-MB-231, MCF-7 and T47D cells. CXCL10 secretion was found to be down-regulated by IL-6, a potentially pro-malignant cytokine in breast cancer. The concomitant expression of CXCR3 and CXCL10 in breast tumor cells suggests that a CXCR3-CXCL10 axis may function in these cells, and paves the way for an in depth analysis of CXCL10-CXCR3 interactions in breast tumor cells.
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PMID:The expression of the chemokine receptor CXCR3 and its ligand, CXCL10, in human breast adenocarcinoma cell lines. 1508 42


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