osteoprotegerin and Neoplasms

Oncogenic events combined with a favourable environment are the two main factors in the oncological process. The tumour microenvironment is composed of a complex, interconnected network of protagonists, including soluble factors such as cytokines, extracellular matrix components, interacting with fibroblasts, endothelial cells, immune cells and various specific cell types depending on the location of the cancer cells (e.g. pulmonary epithelium, osteoblasts). This diversity defines specific "niches" (e.g. vascular, immune, bone niches) involved in tumour growth and the metastatic process. These actors communicate together by direct intercellular communications and/or in an autocrine/paracrine/endocrine manner involving cytokines and growth factors. Among these glycoproteins, RANKL (receptor activator nuclear factor-κB ligand) and its receptor RANK (receptor activator nuclear factor), members of the TNF and TNFR superfamilies, have stimulated the interest of the scientific community. RANK is frequently expressed by cancer cells in contrast with RANKL which is frequently detected in the tumour microenvironment and together they participate in every step in cancer development. Their activities are markedly regulated by osteoprotegerin (OPG, a soluble decoy receptor) and its ligands, and by LGR4, a membrane receptor able to bind RANKL. The aim of the present review is to provide an overview of the functional implication of the RANK/RANKL system in cancer development, and to underline the most recent clinical studies.

Topics: Clinical Trials as Topic; Disease Progression; Gene Expression Regulation, Neoplastic; Humans; Neoplasm Metastasis; Neoplasms; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, G-Protein-Coupled; Signal Transduction; Tumor Microenvironment

Receptor activator of nuclear factor kappa B ligand (RANKL) and its natural antagonist, osteoprotegerin (OPG), are, respectively, an indispensable factor and a potent inhibitor for osteoclast differentiation, activity, and survival. The development of a human monoclonal antibody to RANKL, denosumab, constitutes a novel approach to prevent fragility fractures in osteoporosis, skeletal complications of malignancy, and potentially bone erosions in rheumatoid arthritis (RA). In addition to being expressed by osteoblasts, RANKL is abundantly produced by activated T cells, and synoviocytes in RA, whereas its receptor, RANK, is also expressed by monocytes/macrophages and dendritic cells. However, in preclinical and clinical studies of RA-including patients with some degree of immunosuppression-RANKL inhibitors did not significantly alter inflammatory processes. RANKL, RANK, and OPG deficiency in murine models highlights the important role of this pathway in the development and maturation of the immune system in rodents, including functions of T and/or B cells, whereas OPG overexpression in mice and rats seems innocuous with regard to immunity. In contrast, loss-of-function mutations in humans have more limited effects on immune cells. In clinical studies, the overall rate of infections, cancer, and death was similar with denosumab and placebo. Nevertheless, the risk of severe infections and cancer in some specific tissues remains to be carefully scrutinized.

Topics: Animals; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Arthritis, Rheumatoid; B-Lymphocytes; Bone Resorption; Denosumab; Female; Humans; Infections; Mice; Neoplasms; Osteoblasts; Osteoclasts; Osteoporosis; Osteoprotegerin; RANK Ligand; Rats; Receptor Activator of Nuclear Factor-kappa B; T-Lymphocytes; Tumor Necrosis Factor-alpha

Cancers which damage the human skeleton include multiple myeloma, where the primary tumour colonises bone directly, or breast and prostate cancer, where malignant cells travel from the primary tumour to form clonal outgrowths within the bone. Owing to the interaction of tumour cells with those normally found in the bone microenvironment, such as osteoclasts and osteoblasts, these cancers affect the closely linked processes of bone formation and resorption. As a result, these twin processes contribute to the clinical manifestations of cancer metastasis, including bone pain and pathological fractures. A critical component of physiologically normal bone remodelling, the RANK/RANKL/OPG pathway, has been implicated in the formation of osteolytic, and possibly osteoblastic, lesions, which characterise the bone disease associated with these malignancies. In these cancers that affect the skeleton in this way the abnormally regulated RANK/RANKL system appears to be the final effector pathway. As a result, there has been much research focused upon targeting these molecules using OPG constructs, peptidomimetics, soluble receptor constructs and antibodies to RANKL, in pre-clinical studies. The success of these studies has paved the way for a clinical programme, the success of which is likely to lead to a new therapeutic approach to treating cancers that develop in the skeleton.

Topics: Animals; Bone Resorption; Breast Neoplasms; Female; Humans; Male; Models, Biological; Multiple Myeloma; Neoplasms; Osteoprotegerin; Prostatic Neoplasms; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Signal Transduction; TNF-Related Apoptosis-Inducing Ligand

Having defined a putative anticarcinogenic principle under physiological conditions of the auditory inner ear in the previous part of this study, part 2 is the continuation to evaluate this hypothesis under pathological conditions, i.e. with regard to the inflamed auditory inner ear. Inflammation of the auditory inner ear shows three characteristic phases. It starts with an acute phase, progresses to a fibrotic one and ends with ossification as the last phase. At the end of the fibrotic phase the inflammatory cells disappear, probably due to apoptosis, the ganglion neurons die and the fibrous matrix ossifies. No proliferating cells can be found in this area any more. Thus this kind of inflammation does not result in a restoration of the former state, but always in the destruction of the hearing organ and corresponding neurons. The osteoimmune axis is involved in this characteristic type of inflammation. Important factors hereby are M-CSF, RANKL/RANK and osteoprotegerin. In the inner auditory ear they inhibit the resorption of the fibrotic matrix, induce apoptosis of inflammatory cells and calcification. This inflammatory osteoimmune axis plays an important role at the cancer site as well. The relation of each factor to the other ones is however fundamentally different from that in the inner ear. Consequently inflammatory processes induced by a tumour foster its progression and may induce bone metastasis. Instead of a dominating and enclosing osteoblastic activity like in the inner ear, matrix resolving and often osteoclastic properties are developed allowing the spread of cancer cells. These processes allows us to set out the anticarcinogenic hypothesis more precisely and define its putative mechanistic rationale for the inflamed auditory inner ear.

Topics: Animals; Bone and Bones; Cell Transformation, Neoplastic; Ear Neoplasms; Ear, Inner; Hair Cells, Auditory, Inner; Humans; Labyrinthitis; Macrophage Colony-Stimulating Factor; Neoplasms; Ossification, Heterotopic; Osteoblasts; Osteoprotegerin; RANK Ligand

Carcinomas are composed of neoplastic epithelial cells, which form the heart of the tumor, as well as a variety of mesenchymal cell types and extracellular matrix components that comprise the tumor stroma, often termed its microenvironment. The normal counterparts of some stromal cells are thought to limit tumor growth, while tumor-associated stromal cells have been convincingly shown to actively promote tumor progression via complex heterotypic interactions with the nearby carcinoma cells. More recent advances have revealed that tumor-host interactions extend well beyond the local tissue microenvironment (ie, interactions between the neoplastic cells and the nearby stroma) and that tumors not only respond to, but actively perturb host organs at distant anatomic sites. This indicates that many aspects of tumor biology can only be explained by a detailed understanding of both local and systemic interactions, yet we currently have only a fragmentary understanding of both processes. In this review, we address the recent advances in our understanding of the contributions of local and systemic environments to cancer progression, the ability of tumors to actively perturb the host environment, and current therapeutic approaches that are designed to disrupt tumor-host relationships.

Topics: Bone Marrow; Cell Communication; Cell Movement; Disease Progression; Humans; Lung; Neoplasms; Osteoprotegerin; Paraneoplastic Syndromes; Spleen; Stromal Cells

Osteoprotegerin (OPG) is a secreted glycoprotein central to bone turnover via its role as a decoy receptor for the receptor activator of nuclear factor kappaB ligand (RANKL) and has traditionally been linked to a number of bone-related diseases. However, there is additional evidence that OPG can promote cell survival by inhibiting TNF-related apoptosis-inducing ligand (TRAIL)-induced apoptosis. As a result, a number of in vitro, in vivo and clinical studies have been performed assessing the role of OPG in tumourigenesis. Similar studies have been performed regarding vascular pathologies, resulting from observations of expression and regulation of OPG in the vasculature. This review aims to provide an update on this area and assess the potential protective or detrimental role of OPG in both vascular pathologies and tumourigenesis.

Topics: Animals; Apoptosis; Bone and Bones; Bone Diseases; Cell Survival; Humans; Immune System; Neoplasms; Osteoprotegerin; RANK Ligand; TNF-Related Apoptosis-Inducing Ligand; Vascular Diseases

Osteoprotegerin (OPG) is a soluble tumor necrosis factor receptor family member, which potently inhibits RANKL-mediated osteoclastogenesis. Numerous constructs have been created for therapeutic purposes in which the heparin-binding and death homology domains of OPG were removed and the remaining peptide (amino acids 22-194) was fused to the Fc domain of human IgG1 (OPG-Fc). The administration of OPG-Fc efficiently counteracted bone loss in a variety of preclinical models of cancers. However, several in vitro studies have shown that native or recombinant full-length OPG not only neuralizes RANKL, but also the death-inducing ligand TRAIL, suggesting that OPG might potentially counteract the anti-tumor activity of TRAIL. Additional evidence suggests that full-length OPG possesses RANKL- and TRAIL-independent biological properties, mainly related to the promotion of endothelial cell survival and angiogenesis. Finally, breast tumor cells overexpressing OPG have shown increased bone metastatic potential in vivo. The relevance of these apparently conflicting findings in tumor cell biology is highlighted.

Topics: Cell Survival; Endothelial Cells; Humans; Immunoglobulin G; Neoplasms; Neovascularization, Physiologic; Osteoclasts; Osteoprotegerin; RANK Ligand; Recombinant Fusion Proteins; TNF-Related Apoptosis-Inducing Ligand

Receptor activator of nuclear factor-kB (RANK), its ligand (RANKL) and its decoy receptor osteoprotegerin (OPG) together play a key role in osteoclastogenesis. Alterations in the RANKL/ OPG ratio are central in the pathogenesis of bone loss, from osteoporosis in all its forms to malignancy-induced bone loss. This fact has led to the search for drugs capable of targeted RANKL inhibition in the management of skeletal disorders associated with bone loss. Promising preclinical data using OPG have paved the way for the development of the new agent denosumab, a high-affinity, high-specificity, fully human monoclonal antibody to RANKL, shown to be able to induce a dose-dependent, rapid, profound and sustained inhibition of bone resorption lasting for months after a single subcutaneous injection in healthy postmenopausal women, men and patients with multiple myeloma or metastatic breast cancer. Data from a phase II study in postmenopausal women with low bone mineral density (BMD) demonstrate that the sustained inhibition of bone resorption induced by three or six monthly subcutaneously administered denosumab was associated with significant increases in BMD for up to two years of treatment. Antifracture efficacy and long-term skeletal and extraskeletal safety of denosumab are being addressed in ongoing phase III trials. The potential of denosumab to prevent bone loss has also been demonstrated in malignancy-induced bone loss. Ongoing studies in rheumatoid arthritis are also promising.

Topics: Animals; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Bone Density; Bone Density Conservation Agents; Bone Diseases; Bone Remodeling; Denosumab; Female; Humans; Injections, Subcutaneous; Male; Neoplasms; Osteoporosis, Postmenopausal; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B

Topics: Animals; Bone Density Conservation Agents; Calcitonin; Diphosphonates; Fluid Therapy; Humans; Hypercalcemia; Neoplasms; Osteoprotegerin; Paraneoplastic Syndromes; Parathyroid Hormone-Related Protein; Prednisolone; Sodium; Sodium Potassium Chloride Symporter Inhibitors

Bone integrity is maintained through a balance between bone formation and bone resorption, and osteoclasts are primary cells involved in bone resorption. Recent studies have revealed an essential role of macrophage colony-stimulating factor (M-CSF) and receptor activator of nuclear factor kappa-B ligand (RANKL) in the development of osteoclasts, and detailed molecular cascades that induce osteoclast differentiation, activation and apoptosis have been clarified. Osteoclasts are involved in various pathologic conditions, such as osteoporosis, rheumatoid arthritis and tumor-induced bone disease, which are characterized by abnormal bone resorption, and the finding of RANKL has provided us a good therapeutic target for such pathologic conditions.

Topics: Animals; Arthritis, Rheumatoid; Bone Diseases; Bone Resorption; Humans; Neoplasms; Osteoclasts; Osteoporosis; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Signal Transduction

OPG (osteoprotegerin), a secreted member of the TNF (tumour necrosis factor) receptor superfamily, has a variety of biological functions which include the regulation of bone turnover. OPG is a potent inhibitor of osteoclastic bone resorption and has been investigated as a potential therapeutic for the treatment of both osteoporosis and tumour-induced bone disease. Indeed, in murine models of cancer-induced bone disease, inhibition of osteoclastic activity by OPG was also associated with a reduction in tumour burden. The discovery that OPG can bind to and inhibit the activity of TRAIL (TNF-related apoptosis-inducing ligand) triggered extensive research into the potential role of OPG in the regulation of tumour cell survival. A number of reports from studies using in vitro models have shown that OPG protects tumour cells from the effects of TRAIL, thereby possibly providing tumour cells that produce OPG with a survival advantage. However, the ability of OPG to act as a tumour cell survival factor remains to be verified using appropriate in vivo systems. A third area of interest has been the use of OPG as a prognostic marker in various cancer types, including myeloma, breast and prostate cancer. This review provides an overview of the role of OPG in cancer, both in cancer-induced bone disease and in tumour growth and survival.

Topics: Animals; Apoptosis; Bone Remodeling; Bone Resorption; Cell Survival; Female; Glycoproteins; Humans; Male; Neoplasms; Osteoprotegerin; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor

Malignancy-associated hypercalcemia (MAH) is caused by tumor over-production of parathyroid hormone-related protein (PTHrP), or by locally enhanced bone resorption in metastatic lesions of solid cancers. Medical treatment of MAH includes hydration by saline infusion, loop diuretics to promote urinary calcium excretion and anti-resorptives such as calcitonin and bisphosphonates. Particularly, bisphosphonates are the current mainstay for MAH treatment : they not only inhibit osteoclastic bone resorption to ameliorate hypercalcemia but can also alleviate bone pain and can even prevent cancer cell expansion in bone metastatic lesions.

Topics: Bone Neoplasms; Bone Resorption; Calcitonin; Diphosphonates; Drug Design; Drug Therapy, Combination; Fluid Therapy; Glycoproteins; Humans; Hypercalcemia; Neoplasms; Osteoprotegerin; Parathyroid Hormone-Related Protein; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Sodium Chloride; Sodium Potassium Chloride Symporter Inhibitors

TRAIL is a member of the tumor necrosis factor superfamily that interacts with an unusually complex receptor system, comprising transmembrane (TRAIL-R1, -R2, -R3 and -R4) and soluble (osteoprotegerin) receptors. TRAIL has received considerable attention because of the finding that many cancer cell types are sensitive to TRAIL-induced apoptosis. However, increasing experimental evidence shows that TRAIL exhibits regulatory roles in various normal tissues, as well. Although the best-characterized biological activity of TRAIL is in the homeostatic regulation of the immune system, in this review we have summarized and discussed the physiological function of TRAIL and its receptors, in normal hematopoiesis and vascular physiopathology.

Topics: Animals; Apoptosis Regulatory Proteins; Endothelium, Vascular; Erythropoiesis; Glycoproteins; Hematopoiesis; Humans; Megakaryocytes; Membrane Glycoproteins; Mice; Monocytes; Neoplasms; Osteoprotegerin; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; TNF-Related Apoptosis-Inducing Ligand; Tumor Necrosis Factor-alpha; Vascular Diseases

The discovery of the receptor activator for nuclear factor kappaB (RANK) ligand (RANKL)/RANK signaling pathway has marked a major advance in our understanding of the mechanisms controlling osteoclastogenesis. RANKL, expressed by preosteoblasts and stromal cells, binds to RANK, expressed by cells of the osteoclast lineage, inducing a signaling cascade leading to the differentiation and fusion of osteoclast precursor cells and stimulating the activity of the mature osteoclast. The effects of RANKL are counteracted by osteoprotegerin (OPG), a soluble neutralizing decoy receptor.. This paper reviews the literature surrounding the use of circulating OPG and soluble RANKL (sRANKL) measurements and assesses their potential as markers of bone disease. Original clinical and basic research articles and reviews were identified using a Pubmed search strategy (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi) and cover the time period up until January 2005. Search terms osteoprotegerin, OPG, RANK, RANKL, and RANK ligand were used alone and in combination with bone, osteoporosis, and disease.. Assays for detecting OPG and sRANKL in the circulation in humans have been developed, and differences in the circulating concentrations of OPG and sRANKL have been observed in different disease states. There are, however, some inconsistencies in study outcome. These may relate to differences in study design, methodology, and other unknown factors influencing the variability of these measurements.. The clinical utility of serum OPG and sRANKL measurements as markers of disease activity requires additional investigation. In particular, rigorous testing of assays and identification of the sources of measurement variability are required.

Topics: Bone Diseases, Metabolic; Carrier Proteins; Female; Fracture Healing; Glycoproteins; Humans; Male; Membrane Glycoproteins; Neoplasms; Osteoporosis; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Sex Factors; Vascular Diseases

Topics: Apoptosis; Apoptosis Regulatory Proteins; Carrier Proteins; CASP8 and FADD-Like Apoptosis Regulating Protein; Caspase 8; Caspases; Cell Division; Glycoproteins; Intracellular Signaling Peptides and Proteins; Membrane Glycoproteins; Neoplasms; NF-kappa B; Osteoprotegerin; Proteins; Receptor-Interacting Protein Serine-Threonine Kinases; Receptors, Cytoplasmic and Nuclear; Receptors, TNF-Related Apoptosis-Inducing Ligand; Receptors, Tumor Necrosis Factor; Recombinant Proteins; Signal Transduction; TNF-Related Apoptosis-Inducing Ligand; Tumor Necrosis Factor-alpha

Topics: Animals; Antineoplastic Agents; Apoptosis; Carrier Proteins; CASP8 and FADD-Like Apoptosis Regulating Protein; Caspase 3; Caspase 9; Caspases; Glycoproteins; Humans; Inhibitor of Apoptosis Proteins; Intracellular Signaling Peptides and Proteins; Membrane Glycoproteins; Microtubule-Associated Proteins; Mitochondria; Models, Biological; Neoplasm Proteins; Neoplasms; NF-kappa B; Oligonucleotides, Antisense; Osteoprotegerin; Peptides; Proto-Oncogene Proteins c-bcl-2; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Recombinant Proteins; Signal Transduction; Survivin

Topics: Animals; Apoptosis; Arthritis, Experimental; Carrier Proteins; Glycoproteins; Humans; Hypercalcemia; Lymphocyte Activation; Membrane Glycoproteins; Mice; Mice, Knockout; Mice, Transgenic; Neoplasms; Osteoclasts; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; T-Lymphocytes

The purpose of this study is to determine the levels of procalcitonin (PCT), IL-8 (interleukin-8), MIF (macrophage migration inhibitory factor), osteoprotegerin (OPG), hs-CRP and D-dimer during fever above 38.3°C due to various causes.. Blood samples taken from a total of consecutive 65 hospitalized patients during fever were prospectively tested for hsCRP, PCT, IL-8, OPG, MIF and D-dimer. Of these patients, there were 26 patients presenting with chemotherapy-induced neutropenia who had no infectious agents found; 23 patients, who had a malignancy with a febrile episode which was neither a microbiologically documented infection nor a chemotherapy-induced neutropenia, and 16 patients who did not have a malignancy and were considered to have a clinically and microbiologically documented infection.. IL-8 and D-dimer levels were higher in patients with febrile neutropenia than in the other two groups. Although MIF and OPG were higher in patients with newly diagnosed cancers, there were no differences among the three groups regarding PCT and hs-CRP values.. High serum IL-8 and D-dimer levels can be useful markers to identify hospitalized chemotherapy-induced neutropenia patients. MIF and OPG were found to be higher in patients with newly diagnosed cancer.

Topics: Antineoplastic Agents; C-Reactive Protein; Calcitonin; Calcitonin Gene-Related Peptide; Female; Fever; Fibrin Fibrinogen Degradation Products; Humans; Infections; Interleukin-8; Intramolecular Oxidoreductases; Macrophage Migration-Inhibitory Factors; Male; Neoplasms; Neutropenia; Osteoprotegerin; Prospective Studies; Protein Precursors

Complexities in treating breast cancer with bone metastasis are enhanced by a vicious protumorigenic pathology, involving a shift in skeletal homeostasis toward aggressive osteoclast activity and polarization of immune cells supporting tumor growth and immunosuppression. Recent studies signify the role of receptor activator of NF-κB ligand (RANKL) beyond skeletal pathology in breast cancer, including tumor growth and immunosuppression. By using an osteoprotegerin (OPG) variant, which we developed recently through protein engineering to uncouple TNF-related apoptosis-inducing ligand (TRAIL) binding, this study established the potential of a cell-based OPG

Topics: Animals; Antineoplastic Agents, Immunological; Bone Neoplasms; Bone Remodeling; Cell Line, Tumor; Cytokines; Disease Models, Animal; Female; Humans; Immunohistochemistry; Macrophages; Mice; Neoplasms; Osteoprotegerin; Protein Binding; Receptor Activator of Nuclear Factor-kappa B; T-Lymphocytes; TNF-Related Apoptosis-Inducing Ligand; X-Ray Microtomography

We previously reported that OPG is involved in ischemic tissue neovascularization through the secretion of SDF-1 by pretreated-OPG endothelial colony-forming cells (ECFCs). As the vascularization is one of the key factor influencing the tumour growth and cancer cell dissemination, we investigated whether OPG was able to modulate the invasion of human MNNG-HOS osteosarcoma and DU145 prostate cancer cell lines in vitro and in vivo. Cell motility was analysed in vitro by using Boyden chambers. Human GFP-labelled MMNG-HOS cells were inoculated in immunodeficient mice and the tumour nodules formed were then injected with OPG and/or FGF-2, AMD3100 or 0.9% NaCl (control group). Tumour growth was manually followed and angiogenesis was assessed by immunohistochemistry. In vitro, SDF-1 released by OPG-pretreated ECFCs markedly attracted both MNNG-HOS and DU145 cells and induced spontaneous migration of cancer cells. In vivo, tumour volumes were significantly increased in OPG-treated group compared to the control group and OPG potentiated the effect of FGF-2. Concomitantly, OPG alone or combined with FGF-2 increased the number of new vasculature compared to the control group. Interestingly AMD3100, an inhibitor of SDF-1, prevented the in vivo effects of OPG induced by SDF-1 This study provides experimental evidence that OPG promotes tumour development trough SDF-1/CXCR4 axis.

Topics: Animals; Cell Line, Tumor; Cell Movement; Chemokine CXCL12; Fibroblast Growth Factor 2; Humans; Mice; Neoplasms; Neovascularization, Pathologic; Osteoprotegerin; Receptors, CXCR4; Xenograft Model Antitumor Assays

The purpose was to investigate the association between serum osteoprotegerin (OPG) and risk of incident cancer and cancer mortality in a general population. OPG was measured in serum collected from 6,279 subjects without prior cancer recruited from a general population. Incident cancer and cancer-related mortality were registered from inclusion in 1994-95 until end of follow-up December 31, 2008. Cox regression models were used to estimate crude and adjusted (for age, sex and other confounders) hazard ratios and 95% confidence intervals (HR 95% CI). There were 948 incident cancers and 387 deaths in the cohort during 71,902 person-years of follow up (median 13.5 years). Subjects with serum OPG in the upper tertile had 79% higher risk of incident gastrointestinal cancer than those in the lowest tertile (HR 1.79, 95% CI 1.19-2.67). In women <60 years, serum OPG (per SD 0.81 ng/ml) was associated with reduced risk of incident cancer (all cancers merged; 0.73; 0.57-0.94) and breast cancer (0.51; 0.31-0.83) after adjustment. Subjects in the upper tertile of OPG had higher risk of cancer-related mortality (1.63; 1.16-2.28), particularly mortality from cancer in the gastrointestinal system (2.28; 1.21-4.28) compared to those in the lowest OPG tertile. No significant association was detected between OPG and risk of death from cancer in the respiratory system or death from prostatic cancer. Our findings from a large population based cohort study suggest that serum OPG was associated with increased risk of incident gastrointestinal cancer, inversely associated with breast cancer, and predicts cancer-related mortality.

Topics: Adult; Aged; Aged, 80 and over; Biomarkers; Cohort Studies; Female; Humans; Incidence; Male; Middle Aged; Mortality; Neoplasms; Osteoprotegerin; Population Surveillance; Predictive Value of Tests; Proportional Hazards Models; Risk; Survival Rate; Time Factors

Bone metastases are frequently observed in patients with certain types of cancer and are significant cause of morbidity. Zoledronic acid (ZA) is routinely prescribed for patients with bone metastases by affecting osteoclast function. We aimed to assess the effect of ZA over time in patients with bone metastases by analyzing novel bone turnover marker levels including receptor activator of nuclear factor-k B ligand (RANKL) and osteoprotegerin (OPG) in serum and gingival crevicular fluid (GCF). Also, associations between these bone turnover markers with hematological and biochemistry dysregulation were studied. The study enrolled patients with bone metastases including 32 patients diagnosed with solid tumors and 15 patients with multiple myeloma. In these patients, GCF and serum RANKL and OPG levels were measured and compared with measures of hematological and biochemical parameters before and after 3 months of ZA therapy. Mean subject age was 54 years old with a range of 28-80 years. Skeletal-related events were observed in 8.5% of all patients. After the 3-month treatment of ZA therapy, no significant differences were found in serum and GCF levels of RANKL and OPG when compared with before treatment levels. GCF RANKL levels at baseline and following 3 months of ZA therapy were significantly higher in patients with solid tumors when compared patients diagnosed with multiple myeloma (p=0.001; p<0.001, respectively). GCF OPG levels after the entire course of ZA therapy were greater in patients with 5 or more bone metastases (p=0.04). For patients with multiple myeloma, control GCF OPG was negatively correlated with control platelet and WBC counts (p=0.018 and p=0.027, respectively). A negative correlation was observed between control serum RANKL and control serum OPG levels in myeloma patients (p=0.001). After 3 months of ZA therapy, no significant differences were observed in GCF and serum RANKL and OPG levels when compared with baseline. A negative correlation was observed between serum control RANKL and OPG levels in myeloma patients. OPG levels were greater in patients with 5 or more bone metastases. In patients diagnosed with multiple myeloma, GCF OPG levels were negatively associated with WBC and platelet counts.

Topics: Adult; Aged; Aged, 80 and over; Biomarkers; Bone Density Conservation Agents; Bone Neoplasms; Diphosphonates; Female; Follow-Up Studies; Gingival Crevicular Fluid; Humans; Imidazoles; Male; Middle Aged; Multiple Myeloma; Neoplasm Staging; Neoplasms; Osteoprotegerin; Prognosis; RANK Ligand; Survival Rate; Zoledronic Acid

Thymic central tolerance is a critical process that prevents autoimmunity but also presents a challenge to the generation of anti-tumor immune responses. Medullary thymic epithelial cells (mTECs) eliminate self-reactive T cells by displaying a diverse repertoire of tissue-specific antigens (TSAs) that are also shared by tumors. Therefore, while protecting against autoimmunity, mTECs simultaneously limit the generation of tumor-specific effector T cells by expressing tumor self-antigens. This ectopic expression of TSAs largely depends on autoimmune regulator (Aire), which is expressed in mature mTECs. Thus, therapies to deplete Aire-expressing mTECs represent an attractive strategy to increase the pool of tumor-specific effector T cells. Recent work has implicated the TNF family members RANK and RANK-Ligand (RANKL) in the development of Aire-expressing mTECs. We show that in vivo RANKL blockade selectively and transiently depletes Aire and TSA expression in the thymus to create a window of defective negative selection. Furthermore, we demonstrate that RANKL blockade can rescue melanoma-specific T cells from thymic deletion and that persistence of these tumor-specific effector T cells promoted increased host survival in response to tumor challenge. These results indicate that modulating central tolerance through RANKL can alter thymic output and potentially provide therapeutic benefit by enhancing anti-tumor immunity.

Topics: AIRE Protein; Animals; Antigens, Neoplasm; Autoimmunity; Central Tolerance; Epithelial Cells; Flow Cytometry; Homeodomain Proteins; Indoles; Kaplan-Meier Estimate; Mice; Mice, Inbred C57BL; Mice, Knockout; Microscopy, Fluorescence; Neoplasms; Osteoprotegerin; RANK Ligand; T-Lymphocytes; Thymus Gland; Transcription Factors

Serum levels of sRANKL, RANK, OPG, IL-8, IL-6, IL-16, MMP-2, and calcitonin were measured by ELISA in patients with malignant, borderline, and benign bone tumors and in healthy individuals (control). Serum levels of RANK, OPG, IL-8, IL-6, and the OPG/sRANKL ratio were significantly higher, while the level of MMP-2 was significantly lower in patients with bone tumors than in controls. Serum concentration of IL-16 in osteosarcoma patients was significantly lower than in chondrosarcoma patients. No significant differences between bone sarcomas of different differentiation were detected for any of the studied markers. Calcitonin level depended on the tumor location and type.

Topics: Adolescent; Adult; Aged; Bone Neoplasms; Calcitonin; Case-Control Studies; Chondrosarcoma; Chordoma; Female; Gene Expression; Humans; Interleukin-16; Interleukin-6; Interleukin-8; Male; Matrix Metalloproteinase 2; Middle Aged; Neoplasms; Osteoprotegerin; Osteosarcoma; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B

The identification of soluble factors involved in stem cell renewal is a major goal in the assessment of the BM niche. We have previously shown that human endothelial cell (EC) supernatants can induce the proliferation of hematopoietic progenitor cells (HPCs), especially after stimulation with IL-1β. To identify new potential growth factors, we compared the expression profile of IL-1β-stimulated ECs over 4, 8 and 16 h with non-stimulated ECs using oligonucleotide microarrays covering more than 46,000 transcripts. Most significant changes were detected after 4 h. Utilization of Gene Ontology annotation for the stimulated EC transcriptome indicated multiple upregulated genes encoding extracellular proteins with a cell-cell signaling function. Using flow cytometry, delta, colony and cobblestone assays, we assessed the proliferative capacities of 11 gene products, i.e. IL-8, IL-32, FGF-18, osteoprotegerin, Gro 1-3, ENA78, GCP-2, CCL2 and CCL20, which are not known to induce HPC expansion. Notably, IL-32 and to a lesser degree osteoprotegerin and Gro 3 significantly induced the proliferation of HPCs. Furthermore, IL-32 attenuated chemotherapy-related BM cytotoxicities by increasing the number of HPCs in mice. Our findings confirm that the combination of microarrays and gene annotation helps to identify new hematopoietic growth factors.

Topics: Animals; Apoptosis; Bone Marrow Cells; Cell Communication; Cell Growth Processes; Cell Survival; Cells, Cultured; Chemokines, CXC; Endothelial Cells; Fluorouracil; Gene Expression Profiling; Hematopoietic Stem Cells; Humans; Interleukin-1beta; Interleukins; Mice; Mice, Inbred BALB C; Neoplasms; Oligonucleotide Array Sequence Analysis; Osteoprotegerin

It was recently shown that physiological bone remodeling depends on the dynamic balance of two cytokines that are predominantly secreted by osteoblasts. RANKL promotes the differentiation of osteoclastic precursors and the activation of osteoclasts, whereas osteoprotegerin (OPG)inhibits RANKL action. During the development of many tumors, enhanced osteolysis results in pathological bone destruction. Tumor-associated osteolysis is characterized by the degradation and inhibition of osteoprotegerin (OPG) and increased RANKL expression and secretion by tumor tissue. The resulting RANKL/OPG imbalance causes increased generation and activation of osteoclasts and, finally, a significant decrease in bone mass and pathological bone fractures. Tumor cells may also produce many other factors which affect the RANK/RANKL/OPG system and accelerate osteolysis, including IL-1, IL-6, TNF, and MIP-1alpha. The elucidation of the key mechanisms of tumor osteolysis has led to clinical trials of biological therapies based on the inhibition of RANKL and stimulation of OPG activity.

Topics: Humans; Neoplasms; Osteoblasts; Osteoclasts; Osteolysis; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B

The identification of molecules that are down-regulated in malignant phenotype is important for understanding tumor biology and their role in tumor suppression. We compared the expression profile of four normal nasal mucosal (NNM) epithelia and a series of nasopharyngeal cancinoma (NPC) cell lines using cDNA microarray and confirmed the actual expression of the selected genes, and found osteoprotegerin (OPG) to be ubiquitously deficient in NPC cells. We also found OPG to be down-regulated in various cancer cell lines, including oral, cervical, ovarian, lung, breast, pancreas, colon, renal, prostate cancer, and hepatoma. Administration of recombinant OPG (rOPG) brought about a reduction in cancer cell growth through apoptotic mechanism. We generated eleven monoclonal antibodies (MAbs) against OPG to study OPG's expression and biological functions in cancer cells. OPG was detected in the tumor stromal regions, but not in the cancer cell per se in surgical specimens of liver cancer. Quantitative reverse transcription-polymerase chain reaction (Q-RT-PCR) revealed that OPG was down-regulated in NPC tissues compared with normal nasal polyp (NNP) tissues. In addition, we showed OPG silencing to be associated with promoter methylation as well as histone modifications. In OPG-silenced cancer cell lines, the OPG gene promoter CpG dinucleotides were highly methylated. Compared to normal cells, silenced OPG gene in cancer cells were found to have reduced histone 3 lysine 4 tri-methylation (H3K4me3) and increased histone 3 lysine 27 tri-methylation (H3K27me3). Taken together, these results suggest that OPG silencing in carcinoma cancer cells occurs through epigenetic repression.

Topics: Cell Line, Tumor; DNA Methylation; Epigenesis, Genetic; Gene Expression Regulation, Neoplastic; Gene Silencing; Histones; Humans; Male; Methylation; Neoplasms; Osteoprotegerin; Prostatic Neoplasms

To evaluate serum levels of osteoprotegerin (OPG), soluble receptor activator of the nuclear factor-kappaB (RANKL), and their relationship with FGF-23, lumbar bone mineral density (BMD), and bone turnover markers, five patients with tumor-induced osteomalacia (TIO) and 40 healthy controls were studied. TIO patients were followed for 360 days after surgical removal of underlying tumor (n = 2) or beginning of therapy with phosphate and calcitriol when surgical treatment was impossible (n = 3). At diagnosis, TIO patients had higher levels of FGF-23 and bone-specific alkaline phosphatase (bALP) and lower levels of cathepsin K (CathK), RANKL, and RANKL/OPG ratio compared to controls. During the follow-up, FGF-23 decreased significantly only in patients who underwent a surgical excision, while phosphate and BMD increased in all patients. The increases in BMD, phosphate, and renal phosphate reabsorption rate were directly related. In the first 60 days of follow-up, we observed a prolonged inhibition of RANKL, CathK, and bone resorption markers associated with a persistence of TIO symptoms and an increase in bALP. From day 60, levels of bone turnover markers returned progressively within the normal range and a clinical remission was observed. The inhibition of the RANKL/OPG pathway and the uncoupling of bone formation and resorption observed in patients with active TIO may be a compensatory mechanism, attempting to reduce worsening of osteomalacia. The BMD increase during TIO treatment is related to the improvement of phosphate rather than FGF-23 levels. A "hungry bone"-like syndrome was observed after surgical or pharmacological treatment.

Topics: Bone and Bones; Bone Density; Bone Resorption; Case-Control Studies; Female; Fibroblast Growth Factor-23; Fibroblast Growth Factors; Hemangiopericytoma; Humans; Longitudinal Studies; Male; Middle Aged; Neoplasms; Osteogenesis; Osteomalacia; Osteoprotegerin; RANK Ligand; Signal Transduction

Topics: Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Biomarkers; Bone Density Conservation Agents; Denosumab; Female; Humans; Neoplasms; Osteoporosis, Postmenopausal; Osteoprotegerin; RANK Ligand; Spinal Fractures

A commonly used monoclonal antibody targeting osteoprotegerin (OPG), MAB8051, detects a truncated protein species in breast and prostate cancer cell lysates. OPG expression has been reported to contribute to cell survival of both of these cancers. We hypothesised that the truncated protein represented a unique tumour-associated OPG isoform. However, here we show that the truncated protein identified by MAB8051 in cancer cell lines is carbonic anhydrase II (CA II), also implicated in tumour biology. We clearly demonstrate cross-reactivity of this OPG antibody in western blots. OPG and CA II RNA-interference studies confirmed the identity of the bands. We show almost identical staining patterns between MAB8051 and CA II immunohistochemistry of different human tissue types and human tumour types using serial sections. We conclude that care should be exercised using this antibody for immunohistochemistry studies, without additional in situ hybridisation, or parallel use of other OPG-specific antibodies.

Topics: Amino Acid Sequence; Antibodies, Monoclonal; Carbonic Anhydrase II; Cell Line, Tumor; Gene Expression Regulation, Neoplastic; Humans; Immunohistochemistry; Molecular Sequence Data; Molecular Weight; Neoplasms; Osteoprotegerin; Protein Processing, Post-Translational; RNA, Messenger; RNA, Small Interfering

Topics: Animals; Bone Neoplasms; Carrier Proteins; Glycoproteins; Humans; Membrane Glycoproteins; Mice; Neoplasm Metastasis; Neoplasms; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, CXCR4; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor

Topics: Animals; Carrier Proteins; Cell Death; Glycoproteins; Hypercalcemia; Membrane Glycoproteins; Mice; Models, Biological; Neoplasms; Osteoclasts; Osteoprotegerin; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor

Topics: Acidosis; Analgesics; Animals; Antineoplastic Agents; Atrasentan; Bone Neoplasms; Diphosphonates; Disease Models, Animal; Glycoproteins; Humans; Ion Channels; Neoplasms; Osteoprotegerin; Pain; Pyrrolidines; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor

Topics: Enzyme-Linked Immunosorbent Assay; Glycoproteins; Humans; Neoplasms; Osteoprotegerin; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor

Osteoprotegerin (OPG) is a novel secreted member of the tumor necrosis factor receptor superfamily. In vitro, OPG blocks osteoclastogenesis in a dose-dependent manner. Serum OPG levels were assayed in cancer patients and healthy control subjects using an ELISA.. OPG levels in healthy controls were significantly higher in sera (0.17 ng/ml) than in plasma (0.14 ng/ml). OPG levels did not differ by age in either control group. Serum was available from patients with solid tumors (n = 145), hematological malignancies (n = 111), benign hematological disorders (n = 35), and rheumatologic diseases (n = 60). When adjusted for age and sex, there was no significant OPG elevation in the sera of patients with solid tumors compared with controls (0.2 versus 0.18 ng/ml). When analyzed by site of primary malignancy within the solid tumor patient group, serum OPG elevations were observed only in patients with colorectal cancer (0.29 ng/ml; P < 0.0001) and pancreatic cancer (0.35 ng/ml; P < 0.0001). When analyzed by site of metastasis within the solid tumor patient group, significant elevations in serum OPG were observed only in patients with liver metastases (0.29 ng/ml) and soft tissue metastases (0.21 ng/ml) but not in patients with bone or lung metastases. Within the hematological malignancy group, serum levels of OPG were significantly lower in patients with multiple myeloma (0.12 ng/ml) but were elevated in patients with Hodgkin's disease (0.29 ng/ml) and Non-Hodgkin's Lymphoma (0.24 ng/ml; P = 0.048).. Although some patients with malignancy have significant elevations of circulating OPG, these concentrations do not approach the level that would be expected to suppress osteoclast function.

Topics: Adolescent; Adult; Aged; Case-Control Studies; Enzyme-Linked Immunosorbent Assay; Female; Glycoproteins; Humans; Male; Middle Aged; Neoplasms; Osteoprotegerin; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Rheumatic Diseases