Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0278488 (metastatic breast cancer)
 7,812 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The cellular and humoral mechanisms accounting for tumour osteolysis in metastatic breast cancer are uncertain. Osteoclasts, the specialised multinucleated cells responsible for tumour osteolysis, are derived from monocyte/macrophage precursors. Breast cancer-derived tumour-associated macrophages (TAMs) are capable of osteoclast differentiation but the cellular and humoral mechanisms controlling this activity are uncertain. In this study, TAMs were isolated from primary breast cancers and cultured in the presence and absence of cytokines/growth factors influencing osteoclastogenesis. Extensive TAM-osteoclast differentiation occurred only in the presence of RANKL and M-CSF; this process was inhibited by OPG and RANK:Fc, decoy receptors for RANKL. Breast cancer-derived fibroblasts and human bone stromal cells expressed mRNA for RANKL, OPG and TRAIL, and co-culture of these fibroblasts with human monocytes stimulated osteoclast formation by a RANKL-dependent mechanism. Osteoclast formation and lacunar resorption also occurred by a RANKL-independent mechanism when the conditioned medium from breast cancer cells, MDA-MB-231 and MCF-7, was added (with M-CSF) to monocyte cultures. Our findings indicate that TAMs in breast cancer are capable of osteoclast differentiation and that breast cancer-derived fibroblasts and breast cancer cells contribute to this process by producing soluble factors that influence osteoclast formation by RANKL-dependent and RANKL-independent mechanisms respectively.
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PMID:RANKL-dependent and RANKL-independent mechanisms of macrophage-osteoclast differentiation in breast cancer. 1715 27

Osteoprotegerin (OPG), member of tumor necrosis factor (TNF) receptor superfamily, has various biological functions including bone remodeling. OPG binds to receptor activator of nuclear factor-kB ligand (RANKL) and prevents osteoclastic bone resorption. Recently, OPG has gained more clinical interest as its role in cancer-mediated bone destruction and the potential of RANKL inhibition could act as a novel treatment in tumor-induced bone disease. OPG protects prostate cancer cells from apoptotic effects of TRAIL and therefore provides tumor cells producing OPG with survival advantages. Additionally, the increased RANKL/OPG ratio in metastatic breast cancer results in severe osteolysis. Thus, bone formation and resorption are the crux of cancer metastasis, resulting in bone pain and pathological fractures. This review provides an overview of the role of OPG in cancer-induced bone disease.
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PMID:Mechanism of bone metastasis: the role of osteoprotegerin and of the host-tissue microenvironment-related survival factors. 1920 Oct 81

Successful management of metastatic breast cancer still needs better chemotherapeutic approaches. The combination of fenretinide (4-HPR), a synthetic retinoid inducing apoptosis by ROS generation, and TRAIL, a cell death ligand inducing caspase-dependent apoptosis, might result in more powerful cytotoxic activity. We therefore investigated the cytotoxic activity and resulting cell death mode of this combination in MDA-MB-231 cell line as a representative of metastatic state. Cytotoxicity was assessed by the ATP viability assay while the mode of cell death was determined both morphologically using fluorescence microscopy and biochemically using Western blotting and ELISA. The combination resulted in an additive cytotoxic effect at the doses used. Fragmented and/or pyknotic nuclei, which is a feature of apoptosis, were observed after treatment with fenretinide or TRAIL. However, the combinatorial treatment further increased apoptotic figures. Confirming apoptosis, active caspase-3 and cleaved PARP were increased by fenretinide or TRAIL in both western blotting and ELISA. Again, apoptosis was further increased by the combination. The combination warrants further studies due to its superior cytotoxic activity in the metastatic setting of breast cancer.
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PMID:Additive enhancement of apoptosis by TRAIL and fenretinide in metastatic breast cancer cells in vitro. 2475 19

Brain metastasis in breast cancer is particularly deadly, but effective treatments remain out of reach due to insufficient information about the mechanisms underlying brain metastasis and the potential vulnerabilities of brain-metastatic breast cancer cells. Here, human breast cancer cells and their brain-metastatic derivatives (BrMs) were used to investigate synthetic lethal interactions in BrMs. First, it was demonstrated that c-MYC activity is increased in BrMs and is required for their brain-metastatic ability in a mouse xenograft model. Specifically, c-MYC enhanced brain metastasis by facilitating the following processes within the brain microenvironment: (i) invasive growth of BrMs, (ii) macrophage infiltration, and (iii) GAP junction formation between BrMs and astrocytes by upregulating connexin 43 (GJA1/Cx43). Furthermore, RNA-sequencing (RNA-seq) analysis uncovered a set of c-MYC-regulated genes whose expression is associated with higher risk for brain metastasis in breast cancer patients. Paradoxically, however, increased c-MYC activity in BrMs rendered them more susceptible to TRAIL (TNF-related apoptosis-inducing ligand)-induced apoptosis. In summary, these data not only reveal the brain metastasis-promoting role of c-MYC and a subsequent synthetic lethality with TRAIL, but also delineate the underlying mechanism. This suggests TRAIL-based approaches as potential therapeutic options for brain-metastatic breast cancer. IMPLICATIONS: This study discovers a paradoxical role of c-MYC in promoting metastasis to the brain and in rendering brain-metastatic cells more susceptible to TRAIL, which suggests the existence of an Achilles' heel, thus providing a new therapeutic opportunity for breast cancer patients.
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PMID:c-MYC Drives Breast Cancer Metastasis to the Brain, but Promotes Synthetic Lethality with TRAIL. 3026 55

We have developed a novel therapeutic paradigm ("metabolic priming") for cancer whereby restriction of the essential amino acid methionine activates a number of cell-stress-response pathways that can be selectively targeted to enhance the therapeutic impact of methionine restriction. One example of metabolic priming is the combination of methionine restriction with proapoptotic TRAIL receptor-2 (TRAIL-R2) agonists. Methionine restriction enhances the cell surface expression of TRAIL-R2 selectively in transformed breast epithelial cells and renders them more susceptible to cell death induction by TRAIL-R2 agonists in cellular and murine models of breast cancer. This methods review focuses on preclinical models of breast cancer to investigate metabolic priming by methionine restriction. Multiple cell-based methods are detailed to measure cell viability, cell survival, caspase activity, apoptosis, and matrix detachment-induced cell death (anoikis). In addition, we describe an orthotopic model of metastatic breast cancer that utilizes mCherry-fluorescently-labeled human breast cancer cells. This model captures the entire metastatic cascade from the mammary gland to the lung and mimics key features of the human disease. These breast-cancer models can be readily adapted to other tumor types. Overall, we provide a stepwise, translationally-relevant approach to study metabolic priming in the context of cancer.
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PMID:Preclinical Breast Cancer Models to Investigate Metabolic Priming by Methionine Restriction. 3072 8