Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027627 (metastases)
 103,950 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Osteoprotegerin (OPG) plays a central role in controlling bone resorption. Exogenous administration of OPG has been shown to be effective in preventing osteolysis and limiting the growth of osteolytic metastasis. The objective of this study was to investigate the effects of OPG on osteoblastic prostate cancer (CaP) metastases in an animal model. LuCaP 23.1 cells were injected intra-tibially and Fc-OPG (6.0 mg/kg) was administered subcutaneously three times a week starting either 24 hours prior to cell injection (prevention regimen) or at 4 weeks post-injection (treatment regimen). Changes in bone mineral density at the tumor site were determined by dual x-ray absorptiometry. Tumor growth was monitored by evaluating serum prostate specific antigen (PSA). Fc-OPG did not inhibit establishment of osteoblastic bone lesions of LuCaP 23.1, but it decreased growth of the tumor cells, as determined by decreases in serum PSA levels of 73.0 +/- 44.3% (P < 0.001) and 78.3 +/- 25.3% (P < 0.001) under the treatment and prevention regimens, respectively, compared to the untreated tumor-bearing animals. Administration of Fc-OPG decreased the proliferative index by 35.0% (P = 0.1838) in the treatment group, and 75.2% (P = 0.0358) in the prevention group. The results of this study suggest a potential role for OPG in the treatment of established osteoblastic CaP bone metastases.
Clin Exp Metastasis 2004
PMID:The effect of osteoprotegerin administration on the intra-tibial growth of the osteoblastic LuCaP 23.1 prostate cancer xenograft. 1567 62

It has recently been discovered that the receptor activator of nuclear kappaB-ligand (RANKL) plays a key role in the activation, differentiation and proliferation ofosteoblasts. The effects of RANKL are counteracted by the decoy receptor osteoprotegerin (OPG), which protects against bone resorption by preventing RANKL from coupling to its receptor RANK. An increase in the balance between RANKL and OPG leads to increased bone resorption (both locally and generalised), e.g. in patients with postmenopausal osteoporosis, glucocorticoid-induced osteoporosis, multiple myeloma, other malignancies with skeletal metastases, or rheumatoid arthritis. The development of new anti-osteoporotic drugs, based on the restoration of the imbalance between RANKL and OPG, may be a breakthrough in optimising the treatment of patients with bone diseases. However, the results of studies on fracture reduction, the safety profile, the costs of the new drugs and their comparison with bisphosphonates, currently the gold standard in osteoporosis treatment, must be awaited.
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PMID:[Clinical implications of new insights into the regulation of bone resorption]. 1610 10

The present study was sought to assess the relative use of eight biomarkers for the detection of bone metastases in cancer forms frequently spreading to the skeleton. Participants were 161 patients with either breast, prostate, or lung cancer. The presence and extent of bone metastases was assessed by imaging techniques (computer tomography and/or magnetic resonance imaging) and Technetium-99m scintigraphy. Serum or urinary level of the bone resorption markers (alphaalphaCTX, betabetaCTX, NTX, and ICTP), formation marker (BSAP), and osteoclastogenesis markers (osteoprotegerin, RANKL, and TRAP5b) was measured by commercially available immunoassays. When assessed on a group basis, all biomarkers, except for osteoprotegerin and RANKL, were significantly elevated in patients compared with those without bone metastases (P<0.05). Biomarkers had greater diagnostic value in breast and prostate cancer patients, yet alphaalphaCTX, NTx, and ICTP were able to discriminate lung cancer patients with or without bone metastases (P<0.05). Strong linear associations were seen between the extent of skeletal infiltration and levels of the different biomarkers, except for osteoprotegerin and RANKL. Furthermore, all biomarkers (except for osteoprotegerin and RANKL) were indicative at the early stage of skeletal involvement (one to five metastases). When expressing sensitivity as the percentage increase in biomarker level relative to patients without bone metastases, alphaalphaCTX showed the largest relative increases at each stage of the metastatic disease. These results suggest that closer monitoring of cancer patients with serial measures of biomarkers might facilitate the timely diagnosis of skeletal metastases.
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PMID:The relative use of eight collagenous and noncollagenous markers for diagnosis of skeletal metastases in breast, prostate, or lung cancer patients. 1643 83

Earlier reports showed that the balance between receptor activator of nuclear factor-kappaB ligand (RANKL) and its decoy-receptor osteoprotegerin (OPG) plays an important role in the pathogenesis of metastatic osteolysis induced by neuroblastoma cells. In this study, we investigated whether circulating levels of OPG, RANKL and their ratio were associated to the presence of osteolytic lesions in advanced neuroblastoma, as well as whether they provided additional information on the severity and prognosis of the disease. Plasma levels of RANKL and OPG were measured in 54 newly diagnosed neuroblastomas; 27 of them showed metastatic disease (stage IV), including 19 bone dissemination. Thirty-five children who were admitted to the pediatric department for minor surgical problems served as control group. OPG was significantly lower in all patients compared with controls, while RANKL levels were significantly increased in advanced neuroblastoma. OPG-to-RANKL ratio decreased in stage-IV patients, and particularly in those who had bone metastases. The diagnostic accuracy of the OPG-to-RANKL ratio in discriminating the presence of osteolytic lesions was not confirmed statistically. OPG correlated significantly with other prognostic factors, namely, ferritin and neurone-specific enolase. In addition, an inverse relationship was found between OPG and event-free survival, and it was more significant in patients who had bone metastasis. This pilot study confirms that the production of OPG and RANKL is disregulated in neuroblastoma. Although the OPG-to-RANKL ratio does not have a predictive value in detecting bone metastasis, the measurement of the previously mentioned markers could be useful in decisions regarding the use of adjuvant therapies.
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PMID:Plasma levels of receptor activator of nuclear factor-kappaB ligand and osteoprotegerin in patients with neuroblastoma. 1645 Mar 78

Bone metastases are a frequent complication of many cancers that result in severe disease burden and pain. Since the late nineteenth century, it has been thought that the microenvironment of the local host tissue actively participates in the propensity of certain cancers to metastasize to specific organs, and that bone provides an especially fertile 'soil'. In the case of breast cancers, the local chemokine milieu is now emerging as an explanation for why these tumours preferentially metastasize to certain organs. However, as the inhibition of chemokine receptors in vivo only partially blocks metastatic behaviour, other factors must exist that regulate the preferential metastasis of breast cancer cells. Here we show that the cytokine RANKL (receptor activator of NF-kappaB ligand) triggers migration of human epithelial cancer cells and melanoma cells that express the receptor RANK. RANK is expressed on cancer cell lines and breast cancer cells in patients. In a mouse model of melanoma metastasis, in vivo neutralization of RANKL by osteoprotegerin results in complete protection from paralysis and a marked reduction in tumour burden in bones but not in other organs. Our data show that local differentiation factors such as RANKL have an important role in cell migration and the tissue-specific metastatic behaviour of cancer cells.
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PMID:Regulation of cancer cell migration and bone metastasis by RANKL. 1731 31

The cellular and humoral mechanisms accounting for osteolysis in skeletal metastases of malignant melanoma are uncertain. Osteoclasts, the specialised multinucleated cells that carry out bone resorption, are derived from monocyte/macrophage precursors. We isolated tumour-associated macrophages (TAMs) from metastatic (lymph node/skin) melanomas and cultured them in the presence and absence of osteoclastogenic cytokines and growth factors. The effect of tumour-derived fibroblasts and melanoma cells on osteoclast formation and resorption was also analysed. Melanoma TAMs (CD14+/CD51-) differentiated into osteoclasts (CD14-/CD51+) in the presence of receptor activator for nuclear factor kappaB ligand (RANKL) and macrophage-colony stimulating factor. Tumour-associated macrophage-osteoclast differentiation also occurred via a RANKL-independent pathway when TAMs were cultured with tumour necrosis factor-alpha and interleukin (IL)-1alpha. RT-PCR showed that fibroblasts isolated from metastatic melanomas expressed RANKL messenger RNA and the conditioned medium of cultured melanoma fibroblasts was found to be capable of inducing osteoclast formation in the absence of RANKL; this effect was inhibited by the addition of osteoprotegerin (OPG). We also found that cultured human SK-Mel-29 melanoma cells produce a soluble factor that induces osteoclast differentiation; this effect was not inhibited by OPG. Our findings indicate that TAMs in metastatic melanomas can differentiate into osteoclasts and that melanoma fibroblasts and melanoma tumour cells can induce osteoclast formation by RANKL-dependent and RANKL-independent mechanisms, respectively.
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PMID:Malignant melanoma and bone resorption. 1664 14

The pathogenesis of bone metastases may require the activation of osteoclasts by tumor-secreted factors, which promote important interactions with the bone microenvironment. We utilized an intratibial model of bone metastasis with bioluminescent imaging (BLI) to measure the effect of osteoclast inhibition on the interaction of human lung cancer cells with bone, and on tumor growth. Mice were injected with luciferase-transduced tumor cells (HARA, human pulmonary squamous carcinoma) and divided into three groups: (1) untreated, (2) twice weekly treatment with the bisphosphonate zoledronic acid (ZOL), or (3) osteoprotegerin (OPG). Histomorphometry and imaging were used to evaluate tumor burden, and parameters of osteoclast activity. Mice in the treated groups had increased bone density and decreased osteoclast numbers in nontumor-bearing tibiae. There was greater than 60% reduction in mean tumor volume in both treatment groups when evaluated by histomorphometry (P = 0.06 [OPG], P = 0.07 [ZOL]). However, bioluminescent imaging failed to show a reduction in tumor burden due to wide variability in the data. Osteoclast numbers along tumor-associated bone were significantly increased compared to tumor-free bone, and were not reduced by either treatment. Plasma calcium concentration was increased in all groups. Plasma tartrate-resistant acid phosphatase 5b was reduced in both treatment groups. Plasma PTHrP was significantly increased in the untreated tumor-bearing group, but was not significantly different in the two treatment groups compared to normal mice. OPG or ZOL did not change tumor cell proliferation, but ZOL increased HARA cell apoptosis. OPG and ZOL reduced tumor growth in the tibiae of treated mice, however, PTHrP production by HARA cells may have resulted in a high concentration in the bone microenvironment, partially overriding the antiosteoclast effects of both OPG and ZOL.
Clin Exp Metastasis 2006
PMID:The effect of zoledronic acid and osteoprotegerin on growth of human lung cancer in the tibias of nude mice. 1671 52

The maintenance of skeletal integrity in a healthy individual requires a balanced regulation of the processes of bone formation, mediated by osteoblasts, and bone resorption, mediated by osteoclasts. This balanced process of bone remodeling becomes co-opted in the skeleton by tumor cells and this dramatically accelerates the process of remodeling and disrupts the normal equilibrium resulting in a spectrum of osteolytic to osteoblastic bone lesions. Certain tumor types, such as breast and prostate, frequently metastasize to the bone. It is now widely understood that the molecular triad--receptor activator of NF-kappaB ligand (RANKL), its receptor RANK, and the endogenous soluble RANKL inhibitor, osteoprotegerin (OPG)--play direct and essential roles in the formation, function, and survival of osteoclasts. Osteoclastic bone resorption contributes to the majority of skeletal sequelae, or skeletal-related events (SREs), in patients with bone metastases. In addition, osteoclastic bone resorption also contributes to the establishment of tumors in the skeleton. Therefore, blocking osteoclast activity and differentiation via RANKL inhibition may not only provide a beneficial treatment for skeletal complications of malignancy, but may also prevent bone metastases. In this review, we will first describe the operative role of osteoclasts and the RANK/RANKL/OPG triad in the pathophysiology of cancer-induced bone diseases, specifically solid tumor metastases to the bone. Secondly, we will describe a therapeutic approach that specifically targets the RANKL molecule.
Cancer Metastasis Rev 2006 Dec
PMID:The RANK/RANKL/OPG triad in cancer-induced bone diseases. 1718 Jul 11

Prostate cancer metastases to bone are observed in around 80% of prostate cancer patients and represent the most critical complication of advanced prostate cancer, frequently resulting in significant morbidity and mortality. As the underlying mechanisms are not fully characterized, understanding the biological mechanisms that govern prostate cancer metastases to bone at the molecular level should lead to the determination of new potential therapeutic targets. Receptor activator of NFkappaB ligand (RANKL)/RANK/Osteoprotegerin (OPG) are the key regulators of bone metabolism both in normal and pathological condition, including prostate cancer bone metastases. In the present study, we demonstrated that human prostate cancer cell lines, DU145 and PC3 express biologically functional RANK. Indeed, soluble human RANKL (shRANKL, 100 ng/ml) treatment induced ERK 1/2, p38 and IkappaB phosphorylations in these cells. shRANKL administration also promoted DU145 and PC3 prostate cancer cell invasion in vitro. Whereas human OPG (hOPG) administration alone (100 ng/ml) had no marked effect, combined association of both agents abolished the RANKL-induced DU145 cell invasion. As RANKL had no direct effect on DU145 cell proliferation, the observed effects were indeed related to RANKL-induced cell migration. DU145 human prostate cancer cells promoted osteoclastogenesis of osteoclast precursors generated from mouse bone marrow. Moreover, DU145 cells produced soluble factor(s) that up-regulate the proliferation of MC3T3-E1 pre-osteoblasts through the activation of the ERK 1/2 and STAT3 signal transduction pathways. This stimulation of pre-osteoblast proliferation resulted in an increased local RANKL expression that can activate both osteoclasts/osteoclast precursors and prostate cancer cells, thus facilitating prostate cancer metastasis development in bone. We confirm that RANKL is a factor that facilitates metastasis to bone by acting as an activator of both osteoclasts and RANK-positive prostate cancer cells in our model. Furthermore, the present study provides the evidence that blocking RANKL-RANK interaction offer new therapeutic approach not only at the level of bone resorbing cells, but also by interfering with RANK-positive prostate cancer cells in the prostate cancer bone metastasis development.
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PMID:DU145 human prostate cancer cells express functional receptor activator of NFkappaB: new insights in the prostate cancer bone metastasis process. 1719 95

Breast cancer cells preferentially metastasize to bone, leading to the formation of primarily osteolytic lesions. Osteoprotegerin (OPG) plays multifactorial roles in the development of osteolytic bone metastases. An increase in the ratio of receptor activator of nuclear factor kappaB ligand (RANKL) to OPG increases osteoclastogenesis within the bone microenvironment. OPG also acts as a survival factor for cancer cells by protecting them from tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) mediated apoptosis. This study compares OPG production in vitro in a number of breast cancer cell lines exhibiting both differences in metastatic capacity and in preferential metastasis to bone. Our studies demonstrated that OPG expression by MDA-231, MDA-MET, and MDA-231/K cancer cells was directly correlated with bone specific homing and colonization potential but not with metastasis of cancer cells to other organs; both in IL-1 beta stimulated and control cells. We also demonstrated expression of other bone-related markers including type I collagen, osteocalcin, osteopontin, and Runx2 in these cells. However, the generally lower expression of these markers in the bone selective cell line MDA-MET suggested that increased OPG expression in the bone specific variant was not merely a consequence of enhanced osteomimicry by these cells but that it has a significant role in the metastatic process. Co-culture of breast cancer cells with osteoblastic cells (hFOB 1.19) led to an overall downregulation in OPG production, which was not affected by the bone homing and colonization potential of the cell lines, suggesting that OPG alone is not indicative of osteolytic bone activity by breast cancer cells.
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PMID:Osteoprotegrin and the bone homing and colonization potential of breast cancer cells. 1747 10


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