Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0376358 (prostate cancer)
59,338 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Metastasis of prostate cancer to bone is a common complication of progressive prostate cancer. Skeletal metastases are often associated with severe pain and thus demand therapeutic interventions. Although often characterized as osteoblastic, prostate cancer skeletal metastases usually have an underlying osteoclastic component. Advances in osteoclast biology and pathophysiology have led toward defining putative therapeutic targets to attack tumor-induced osteolysis. Several factors have been found to be important in tumor-induced promotion of osteoclast activity. One key factor is the protein receptor activator of nuclear factor-kappa B ligand (RANKL), which is required to induce osteoclastogenesis. RANKL is produced by prostate cancer bone metastases, enabling these metastases to induce osteolysis through osteoclast activation. Another factor, osteoprotegerin, is a soluble decoy receptor for RANKL and inhibits RANKL-induced osteoclastogenesis. Osteoprotegerin has been shown in murine models to inhibit tumor-induced osteolysis. In addition to RANKL, parathyroid hormone-related protein and interleukin-6 are produced by prostate cancer cells and can promote osteoclastogenesis. Finally, matrix metalloproteinases (MMPs) are secreted by prostate cancer cells and promote osteolysis primarily through degradation of the nonmineralized bone matrix. MMP inhibitors have been shown to diminish tumor establishment in bone in murine models. Thus, many factors derived from prostate cancer metastases can promote osteolysis, and these factors may serve as therapeutic targets. The importance of osteoclasts in the establishment and progression of skeletal metastases has led to clinical evaluation of therapeutic agents to target them for slowing metastatic progression. Bisphosphonates are a class of compounds that decrease osteoclast life span by promoting their apoptosis. The bisphosphonate pamidronate has proven clinical efficacy for relieving bone pain associated with breast cancer metastases and has a promising outlook for prostate cancer metastases. Another bisphosphonate, zoledronic acid, appears to directly target prostate cancer cells in addition to diminishing osteoclast activity at the metastatic site. In addition to bisphosphonates, other novel therapies based on studies that delineate mechanisms of skeletal metastases establishment and progression will be developed in the near future.
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PMID:The role of osteoclastic activity in prostate cancer skeletal metastases. 1253 87

Prostate cancer (CaP) develops metastatic bone lesions that consist of a mixture of osteosclerosis and osteolysis. We have previously demonstrated that targeting receptor activator of nuclear factor kappaB ligand (RANKL) with osteoprotegerin (OPG) prevents the osteolytic activity of CaP and its ability to establish tumor in bone. However, OPG can block tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-mediated apoptosis, suggesting that the clinical use of OPG may prevent apoptosis of tumors mediated by TRAIL. Thus, methods to block RANKL activity, other than OPG, may be important. Accordingly, we evaluated the ability of soluble murine RANK-Fc (sRANK-Fc) to prevent progression of established CaP in a severe combined immunodeficient mouse implanted with fetal human bone. We first confirmed that sRANK did not block TRAIL-mediated apoptosis of LuCaP cells in vitro and that it did block LuCaP-conditioned media-induced osteoclastogenesis in vitro. Then, LuCaP 35 CaP cells were injected into the marrow space of the bone implanted in the severe combined immunodeficient mice implanted with fetal human bone and allowed to develop into tumors for 6 weeks. Either vehicle or sRANK-Fc was then administered for 6 weeks. sRANK-Fc diminished tumor-induced osteoblastic lesions as demonstrated by radiograph, bone mineral density measurement, and bone histomorphometry. sRANK-Fc also reduced systemic bone remodeling markers, including serum osteocalcin and bone-specific alkaline phosphatase and urine N-telopeptide of collagen. Finally, sRANK-Fc decreased serum prostate-specific antigen levels and tumor volume in the bone, which indicates decreased tumor burden. In contrast, sRANK-Fc had no effect on s.c. implanted LuCaP cells. We conclude that sRANK-Fc is an effective inhibitor of RANKL that diminishes progression of CaP growth in bone through inhibition of bone remodeling.
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PMID:Soluble receptor activator of nuclear factor kappaB Fc diminishes prostate cancer progression in bone. 1463 17

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

Inflammation enhances tumour promotion through NF-kappaB-dependent mechanisms. NF-kappaB was also proposed to promote metastatogenesis through epithelial-mesenchymal transition. Yet a mechanistic link between inflammation and metastasis is missing. We identified a role for IkappaB kinase alpha (IKKalpha), activated by receptor activator of NF-kappaB (RANK/TNFRSF11A), in mammary epithelial proliferation during pregnancy. Owing to similarities between mammary and prostate epithelia, we examined IKKalpha involvement in prostate cancer and its progression. Here we show that a mutation that prevents IKKalpha activation slows down CaP growth and inhibits metastatogenesis in TRAMP mice, which express SV40 T antigen in the prostate epithelium. Decreased metastasis correlated with elevated expression of the metastasis suppressor Maspin, the ablation of which restored metastatic activity. IKKalpha activation by RANK ligand (RANKL/TNFSF11) inhibits Maspin expression in prostate epithelial cells, whereas repression of Maspin transcription requires nuclear translocation of active IKKalpha. The amount of active nuclear IKKalpha in mouse and human prostate cancer correlates with metastatic progression, reduced Maspin expression and infiltration of prostate tumours with RANKL-expressing inflammatory cells. We propose that tumour-infiltrating RANKL-expressing cells lead to nuclear IKKalpha activation and inhibition of Maspin transcription, thereby promoting the metastatic phenotype.
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PMID:Nuclear cytokine-activated IKKalpha controls prostate cancer metastasis by repressing Maspin. 1737 33

Newly formed bone in the typically osteoblastic bone metastases from prostate cancer shows characteristics of woven bone, e.g. marked defects in mineralization and microstructure. Adding to the reduced mechanical strength of prostate cancer bone metastasis is an increasingly recognized osteolytic component. The existence of osteoclasts in osteoblastic bone metastases and concomitant increases in urine or serum markers for bone resorption are reported in affected patients. Pathologically increased osteoclastic bone resorption is a key mediator of the clinical complications from bone metastases, among them fractures, spinal cord compression and bone pain. The receptor activator of nuclear factor (NF)-kappaB ligand (RANKL) pathway has been identified as the main driving force for osteoclastogenesis and resulting bone resorption. Emerging data indicate that bone marrow-derived RANKL might also constitute a chemoattractant factor for RANK-expressing tumour cells that is likely to contribute to the pathogenesis of bone metastases, including those arising from prostate cancer. Cumulative evidence supports RANKL inhibition as a therapeutic goal for the treatment and prevention of bone metastases from prostate cancer.
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PMID:Targeting the receptor activator of nuclear factor-kappaB (RANK) ligand in prostate cancer bone metastases. 1807 Jan 91

Tumor cells induce excessive osteoclastogenesis, mediating pathologic bone resorption and subsequent release of growth factors and calcium from bone matrix, resulting in a "vicious cycle" of bone breakdown and tumor proliferation. RANK ligand (RANKL) is an essential mediator of osteoclast formation, function, and survival. In metastatic prostate cancer models, RANKL inhibition directly prevents osteolysis via blockade of osteoclastogenesis and indirectly reduces progression of skeletal tumor burden by reducing local growth factor and calcium concentrations. Docetaxel, a well-established chemotherapy for metastatic hormone-refractory prostate cancer, arrests the cell cycle and induces apoptosis of tumor cells. Suppression of osteoclastogenesis through RANKL inhibition may enhance the effects of docetaxel on skeletal tumors. We evaluated the combination of the RANKL inhibitor osteoprotegerin-Fc (OPG-Fc) with docetaxel in a murine model of prostate cancer bone metastasis. Tumor progression, tumor area, and tumor proliferation and apoptosis were assessed. OPG-Fc alone reduced bone resorption (P < 0.001 versus PBS), inhibited progression of established osteolytic lesions, and reduced tumor area (P < 0.0001 versus PBS). Docetaxel alone reduced tumor burden (P < 0.0001 versus PBS) and delayed the development of osteolytic lesions. OPG-Fc in combination with docetaxel suppressed skeletal tumor burden (P = 0.0005) and increased median survival time by 16.7% (P = 0.0385) compared with docetaxel alone. RANKL inhibition may enhance docetaxel effects by increasing tumor cell apoptosis as evident by increased active caspase-3. These studies show that inhibition of RANKL provides an additive benefit to docetaxel treatment in a murine model of prostate cancer bone metastasis and supports clinical evaluation of this treatment option in patients.
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PMID:RANK ligand inhibition plus docetaxel improves survival and reduces tumor burden in a murine model of prostate cancer bone metastasis. 1860 16

Metastasis to bone is the leading cause of morbidity and mortality in advanced prostate cancer patients. Considering the complex reciprocal interactions between the tumor cells and the bone microenvironment, there is increasing interest in developing combination therapies targeting both the tumor growth and the bone microenvironment. In this study, we investigated the effect of simultaneous blockade of BMP pathway and RANK/RANKL axis in an osteolytic prostate cancer lesion in bone. We used a retroviral vector encoding noggin (RetroNoggin) to antagonize the effect of BMPs and RANK:Fc, which is a recombinant RANKL antagonist was used to inhibit RANK/RANKL axis. The tumor growth and bone loss were evaluated using plain radiographs, hind limb tumor measurements, micro PET/CT ((18)FDG and (18)F-fluoride tracer), and histology. Tibias implanted with PC-3 cells developed pure osteolytic lesions at 2-weeks with progressive increase in cortical bone destruction at successive time points. Tibias implanted with PC-3 cells over expressing noggin (RetroNoggin) resulted in reduced tumor size and decreased bone loss compared to the implanted tibias in untreated control animals. RANK:Fc administration inhibited the formation of osteoclasts, delayed the development of osteolytic lesions, decreased bone loss and reduced tumor size in tibias implanted with PC-3 cells. The combination therapy with RANK:Fc and noggin over expression effectively delayed the radiographic development of osteolytic lesions, and decreased the bone loss and tumor burden compared to implanted tibias treated with noggin over expression alone. Furthermore, the animals treated with the combination strategy exhibited decreased bone loss (micro CT) and lower tumor burden (FDG micro PET) compared to animals treated with RANK:Fc alone. Combined blockade of RANK/RANKL axis and BMP pathway resulted in reduced tumor burden and decreased bone loss compared to inhibition of either individual pathway alone in osteolytic prostate cancer lesion in bone. These results suggest that simultaneous targeting of tumor cells and osteoclasts may be the most effective method of inhibiting the progression of established osteolytic metastatic lesions in vivo.
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PMID:Influence of simultaneous targeting of the bone morphogenetic protein pathway and RANK/RANKL axis in osteolytic prostate cancer lesion in bone. 1892 92

Bone is the preferred site of prostate cancer metastasis, contributing to the morbidity and mortality of this disease. A key step in the successful establishment of prostate cancer bone metastases is activation of osteoclasts with subsequent bone resorption causing the release of several growth factors from the bone matrix. CD11b+ cells in bone marrow are enriched for osteoclast precursors. Conditioned media from prostate cancer PC-3 cells induces CD11b+ cells from human peripheral blood to differentiate into functional osteoclasts with subsequent bone resorption. Analysis of PC-3 conditioned media revealed high amounts of IL-6 and IL-8. CD11b+ cells were cultured with M-CSF and RANKL, IL-6, IL-8, and CCL2, alone or in combination. All of these conditions induced osteoclast fusion, but cells cultured with M-CSF, IL-6, IL-8, and CCL2 were capable of limited bone resorption. Co-incubation with IL-6 and IL-8 and the RANK inhibitor, RANK-Fc, failed to inhibit osteoclast fusion and bone resorption, suggesting a potential RANKL-independent mechanism of functional osteoclast formation. This study demonstrates that functional osteoclasts can be derived from CD11b+ cells derived from human PBMCs. Prostate cancer cells secrete factors, including IL-6 and IL-8, that play an important role in osteoclast fusion by a RANKL-independent mechanism.
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PMID:Prostate cancer promotes CD11b positive cells to differentiate into osteoclasts. 1917 75

Despite that greater knowledge of prostate cancer biology has led to the isolation of many new and promising targets, treatment of metastatic prostate cancer is still challenging. New agents targeting these molecules are currently under development in large randomized phase III trials, to improve overall survival and the quality of life of patients with metastatic castrate-resistant prostatic cancer (CRPC). Cytotoxic chemotherapy (docetaxel-based chemotherapy) demonstrated clinical benefit on overall survival, but could be improved. Drugs targeting directly or not the androgen receptor such as abiraterone or new specific peripheral anti-androgens (MDV3100) are very promising. Bone targeted therapies (endothelin1 receptor A inhibitor, RANK ligant, metabolic irradiation) are also very promising and are in development in large phase III trials. Antiangiogenic therapies could also be effective in CRPC. Autologous vaccin against prostatic acid phosphatase seems to prolong overall survival and other vaccin and immunotherapy strategies are in development (anti-CTLA4 antibody). A recent analogue of thalidomide, probably more efficient, lenalidomide is also in development.
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PMID:[New drugs in metastatic castration-resistant prostate cancer]. 2002 54

This article reviews the concepts and rationale behind targeted agents that are currently in clinical testing for patients with castration resistant prostate cancer (CRPC). Advances in our understanding of the molecular mechanisms underlying prostate cancer progression has translated into a variety of treatment approaches. Agents targeting androgen receptor activation and local steroidogenesis, angiogenesis, apoptosis, chaperone proteins, the insulinlike growth factor pathway, RANK ligand, endothelin receptors, and Src family kinases are entering, or have recently completed, accrual to phase III trials for patients with CRPC. There has also been interest generated by data from early-phase studies evaluating multitargeted tyrosine kinase inhibitors, agents effecting signal transduction pathways, and novel cytotoxics.
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PMID:Novel targeted therapies for prostate cancer. 2015 24


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