osteoprotegerin and Prostatic-Neoplasms

Patients with advanced prostate cancer often develop bone metastases, leading to bone pain, skeletal fracture, and increased mortality. Bone provides a hospitable microenvironment to tumor cells. The disease manifestation is driven by the interaction between invading tumor cells, bone-forming osteoblasts, and bone-resorbing osteoclasts. The increased level of osteoclast-activating factor (parathyroid hormone-related peptide, PTHrP) is believed to induce bone resorption by upregulating receptor activator of nuclear factor-kappa B ligand (RANKL) and the release of various growth factors into the bone microenvironment to enhance cancer cell growth. However, the underlying molecular mechanisms remain poorly understood. This review outlines the possible molecular mechanisms involved in governing bone metastases driven by prostate cancer, which further provide the basis in searching for new molecular targets for the development of potential therapy.

Topics: Animals; Bone Neoplasms; Humans; Intercellular Signaling Peptides and Proteins; Male; Osteoprotegerin; Parathyroid Hormone-Related Protein; Prostatic Neoplasms; RANK Ligand; Signal Transduction

Bone metastasis leads to skeletal-related events in final-stage cancer patients. The incidence of prostate and lung cancers increases yearly; these cancers readily invade the bone. Some recent studies have found that serum osteoprotegerin (OPG) levels may be altered in patients with bone metastasis, whereas other reports have produced inconsistent findings. Hence, we conducted a meta-analysis to examine the effects of lung and prostate cancer on serum OPG levels. A systematic literature search was conducted using PubMed, Medline, and CNKI to identify relevant studies. A total of 11 studies were included. The standardized mean difference (SMD) and 95% confidence interval (95% CI) of the bone metastasis (BM) group, the non-bone metastasis (BM-) group and healthy controls were calculated. In prostate cancer, serum OPG levels in the BM group were higher than in the BM- group and healthy controls. Additionally, no significant difference in serum OPG levels was found between the BM- group and healthy controls. In lung cancer, serum OPG levels in the BM and BM- groups were significantly increased compared with healthy controls. However, no significant difference in serum OPG levels was found between the BM and BM- groups. Studies with larger sample sizes are required to confirm these findings.

Topics: Bone Neoplasms; Humans; Lung Neoplasms; Male; Neoplasm Metastasis; Osteoprotegerin; Prostatic Neoplasms

Disbalance of bone homeostasis, associated with malfunctioning of RANK/RANKL/OPG system underlies the oncological processes such as the destruction of bone, metastasis development, tumor progression. Pathological activity of system was described in such conditions, as breast cancer, prostate cancer, multiple myeloma, squamous cell carcinoma, Hodgkin's disease, and also metastasis in bones from lung cancer and other malignant diseases. In the literature, there is evidence of involvement of RANK/RANKL/OPG system in the pathogenesis of bone tumors (osteosarcoma, giant cell tumor of bone, chondroblastoma). Experimental data show that RANKL inhibitors can play a role in reducing tumor-induced lesions of bone in multiple myeloma, breast cancer, prostate cancer and lung cancer. Also this review presents data from clinical studies of the drug efficacy targeted on RANK/RANKL/OPG system and results of authors' study of the levels of this system's components and proinflammatory cytokines in blood serum of primary bone sarcoma patients.

Topics: Animals; Antineoplastic Agents; Bone Neoplasms; Breast Neoplasms; Cytokines; Female; Humans; Lung Neoplasms; Male; Multiple Myeloma; Osteoprotegerin; Prostatic Neoplasms; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Signal Transduction

Osteoprotegerin (OPG) acts as a soluble decoy receptor for the bone marrow stroma cell-derived and osteoblast-derived receptor activator of nuclear factor-kB ligand (RANKL), thus regulating the RANK-mediated osteoclastogenesis and osteoclast-mediated bone resorption at the metastatic niche of cancer in skeleton.. This article discusses the 'key' role of OPG expression during the early events of cancer cell invasion into the bone matrix and the subsequent events underlying the formation of osteoblastic metastasis, a unique event observed in human prostate cancer biology.. Understanding the cellular and molecular events implicated in bone metastasis can facilitate designing new therapeutic strategies for targeting early and/or late events in the metastasis processes. The RANKL/RANK/OPG pathway is a key regulator of pathological bone metabolism in metastatic sites. Targeted manipulation of these molecules may provide sustainable antitumor responses.

Topics: Animals; Bone Neoplasms; Humans; Male; Osteoblasts; Osteoprotegerin; Prostatic Neoplasms

Bone metastasis is a debilitating side effect of advanced prostatic carcinoma impacting nearly all of the men developing this disease. Even though a majority of these lesions are considered osteoblastic, it is believed that there is an underlying osteolytic component. Lytic processes are governed primarily by osteoclasts, the primary bone resorptive cell. Osteolysis has been implicated in tumor cell seeding and nourishment of tumor growth via development of pro-tumorigenic changes in the microenvironment. Herein, we provide a current view of the processes involved in regulating osteolysis in the presence of prostate cancer bone metastases. Several factors have been implicated in the division, differentiation, and activation of osteoclasts, including, but not limited to, interleukin-6, receptor activator of nuclear factor kappa B ligand (RANKL), osteoprotegerin (OPG), and parathyroid hormone-related protein (PTHrP). Effector molecules in bone resorption play a significant role, such as matrix metalloproteinases (MMPs), cathepsins, and acid secretion. The primary method for treating skeletal events associated with prostate cancer bone metastases has been bisphosphonates. However, a new therapeutic, denosumab, a monoclonal antibody that inhibits RANKL in a mechanism similar to that attributed to the endogenous mediator OPG, has received approval for treatment of skeletally associated metastases. Additional novel targets are continuously being developed for bone metastases. In this review, we describe the processes involved in osteolysis of the prostate cancer bone microenvironment, and introduce therapeutics that may play a role in inhibiting tumor growth leading to increased survival and quality of life.

Topics: Bone Neoplasms; Bone Resorption; Humans; Interleukin-6; Male; Osteoclasts; Osteoprotegerin; Parathyroid Hormone-Related Protein; Prostatic Neoplasms; RANK Ligand

Prostate cancer is known to have a tissue tropism for bone. This tissue tropism coupled with the experience with androgen deprivation therapy (ADT) over the past decade has led to heightened awareness of bone complications. Osteopenia and subsequent skeletal-related events (SREs) are one of the more concerning repercussions of ADT along with cardiovascular sequelae. To combat this decrease in bone mineral density, several agents have been developed for bone protection. The largest experience is with bisphosphonates (BPs), but recently (2011) head to head trials have established the role of monoclonal antibodies, particularly in patients with prostate cancer bone metastasis. For patients initiating ADT, monthly denosumab increased bone mineral density, the time for occurrence of any bone metastasis and time for symptomatic bone metastasis. Denosumab is a fully human monoclonal antibody of the IgG(2) subtype that selectively binds and neutralizes receptor activator NF kappa B ligand (RANKL), inhibiting osteoclastogenesis and bone turnover. In vitro binding assays have shown high-affinity binding of denosumab and osteoprotegerin to both soluble and membrane-bound forms of human RANKL. As clinicians may be less familiar with this newer agent, we compiled this review to summarize denosumab's current clinical indications for bone stabilization and mechanism of reduction in tumor burden.

Topics: Animals; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antineoplastic Agents; Bone and Bones; Clinical Trials as Topic; Denosumab; Gene Expression Regulation, Neoplastic; Humans; Male; Osteoprotegerin; Prostatic Neoplasms; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Tumor Burden; Tumor Microenvironment

Bone homeostasis is maintained by the remodelling of bone which depends on a balance between osteoclast-mediated bone resorption and osteoblast-mediated bone formation. Malignant bone lesions are very common in patients with cancer; whether they result from a tumor in bone (giant cell tumour of bone, osteosarcoma, multiple myeloma...) or they are bony metastases from advanced cancers of which the most osteotropic are breast and prostate cancer. Malignant cells within the bone disrupt the normal bone remodelling process, leading to increased bone destruction and occurence of pathological fractures. Receptor activator of NF-kB (RANK) and its ligand (RANKL) play a pivotal role in the regulation of bone remodelling; by binding to RANK, RANKL stimulates osteoclastogenesis and bone resorption, whereas its cognate decoy receptor osteoprotegerin (OPG) blocks this process by interacting with RANKL. Tumour cells produce different factors that manipulate the RANK/RANKL/OPG pathway in order to stimulate bone destruction. Furthermore, pending on the tumour type, RANKL plays a role in the migration, invasion and proliferation of malignant cells within the bone, while OPG increases survival of tumour cells. Inhibition of RANK/RANKL system may therefore offer new therapeutic perspectives for the treatment of primitive and secondary bone cancers.

Topics: Bone Neoplasms; Bone Remodeling; Bone Resorption; Breast Neoplasms; Female; Homeostasis; Humans; Male; Multiple Myeloma; Neoplasm Proteins; Osteoprotegerin; Prostatic Neoplasms; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B

Cancer development is complex and involves several layers of interactions and pleotropic signaling mechanisms leading to progression. Cancer cells associate with resident stromal fibroblasts, smooth muscle cells, macrophages, endothelium, neurons and migrating cells at metastatic sites and phenotypically and genotypically activate them. These become an integral part of the cancer cell community through activated cell signaling mechanisms. During this process, the cancer cells and cells in the cancer microenvironment "co-evolve" in part due to oxidative stress, and acquire the ability to mimic other cell types (which can be termed osteomimicry, vasculomimicry, neuromimicry and stem cell mimicry), and undergo transition from epithelium to mesenchyme with definitive morphologic and behavioral modifications. In our laboratory, we demonstrated that prostate cancer cells co-evolve in their genotypic and phenotypic characters with stroma and acquire osteomimetic properties allowing them to proliferate and survive in the skeleton as bone metastasis. Several signaling interactions in the bone microenvironment, mediated by reactive oxygen species, soluble and membrane bound factors, such as superoxide, beta2-microglobulin and RANKL have been described. Targeting the signaling pathways in the cancer-associated stromal microenvironment in combination with known conventional therapeutic modalities could have a synergistic effect on cancer treatment. Since cancer cells are constantly interacting and acquiring adaptive and survival changes primarily directed by their microenvironment, it is imperative to delineate these interactions and co-target both cancer and stroma to improve the treatment and overall survival of cancer patients.

Topics: Bone Neoplasms; Disease Progression; Humans; Male; Neoplasm Metastasis; Osteoblasts; Osteoprotegerin; Oxidative Stress; Prostatic Neoplasms; RANK Ligand; Stromal Cells

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

Bone metastasis is often the penultimate harbinger of death for many cancer patients. Bone metastases are often associated with fractures and severe pain resulting in decreased quality of life. Accordingly, effective therapies to inhibit the development or progression of bone metastases will have important clinical benefits. To achieve this goal understanding the mechanisms through which bone metastases develop and progress may provide targets to inhibit the metastases. In the past few years, there have been advances in both understanding the mechanisms through which bone metastases develop and how they impact bone remodeling. Additionally, gains in promising clinical strategies to target bone metastases have been developed. In this prospectus, we will discuss some of these advances.

Topics: Antineoplastic Agents; Bone Neoplasms; Breast Neoplasms; Diphosphonates; Female; Humans; Male; Neoplasm Metastasis; Osteolysis; Osteoprotegerin; Prostatic Neoplasms; RANK Ligand

Skeletal-related complications occur commonly in many solid tumors including breast, prostate and lung cancer as well as multiple myeloma. In addition, malignancies and their associated treatment may result in bone loss or osteoporosis. This review will focus solely on recent data associated with metastatic bone disease with a focus on breast cancer, prostate cancer and multiple myeloma. Bone loss or osteoporosis associated with cancer will be covered in a separate article in this issue.. Recent progress in understanding the pathophysiology of bone metastases has pointed to several novel pathways: transforming growth factor beta; receptor activator of nuclear factor beta ligand and osteoprotegerin; and Wnt signaling pathways and associated factors such as dickkopf-1 and endothelin-1.. The identification of new pathways is important in metastatic bone disease from cancer and has allowed for the development of novel therapeutics aimed at preventing the devastating complications of bone metastases. Bisphosphonates remain the predominant therapy in use for the treatment and prevention of skeletal-related adverse effects from cancer.

Topics: Bone Density Conservation Agents; Bone Neoplasms; Breast Neoplasms; Diphosphonates; Endothelin-1; Female; Humans; Intercellular Signaling Peptides and Proteins; Male; Multiple Myeloma; Osteoprotegerin; Prostatic Neoplasms; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Signal Transduction; Transforming Growth Factor beta; Wnt Proteins

Prostate-specific antigen (PSA) is currently the most important biochemical marker for the diagnosis of prostate cancer. Because of the limited specificity of PSA, clinically irrelevant tumours and benign abnormalities are also detected that potentially lead to over-treatment and the accompanying physical and emotional burden for the patient. In addition, PSA is used as an indicator of progression or clinical response after treatment for prostate cancer, but the prognostic value of this marker is limited. Current studies are evaluating a number of alternative markers, such as PSA-related parameters, human kallikrein 2, osteoprotegerin and the gene DD3(PCA3), that may improve the specificity of current PSA-based diagnostics and the prognostic value of PSA.

Topics: Antigens, Neoplasm; Biomarkers, Tumor; Diagnosis, Differential; Gene Expression Regulation, Neoplastic; Glycoproteins; Humans; Male; Osteoprotegerin; Predictive Value of Tests; Prognosis; Prostate-Specific Antigen; Prostatic Neoplasms; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Sensitivity and Specificity; Tissue Kallikreins

The incidence of prostate cancer has increased dramatically during the last 10-15 years and it is now the commonest cancer in males in developed countries. The increase is mainly caused by the increasing use of opportunistic screening or case-finding based on the use of prostate-specific antigen (PSA) testing in serum. With this approach, prostate cancer is detected 5-10 years before giving rise to symptoms and on average 17 years before causing the death of the patient. While this has led to detection of prostate cancer at a potentially curable stage, it has also led to substantial overdiagnosis, i.e. detection of cancers that would not surface clinically in the absence of screening. A major challenge is thus to identify the cases that need to be treated while avoiding diagnosing patients who will not benefit from being diagnosed and who will only suffer from the stigma of being a cancer patient. It would be useful to have prognostic markers that could predict which patients need to be diagnosed and which do not. Ideally, it should be possible to measure these markers using non-invasive techniques, i.e. by means of serum or urine tests. As it is very useful for both early diagnosis and monitoring of prostate cancer, PSA is considered the most valuable marker available for any tumor. Although the prognostic value of PSA is limited, measurement of the proportion of free PSA has improved the identification of patients with aggressive disease. Furthermore, the rate of increase in serum PSA reflects tumor growth rate and prognosis but, due to substantial physiological variation in serum PSA, reliable estimation of the rate of PSA increase requires follow-up for at least 2 years. Algorithms based on the combined use of free and total PSA and prostate volume in logistic regression and neural networks can improve the diagnostic accuracy for prostate cancer, and assays for minor subfractions of PSA and other new markers may provide additional prognostic information. Markers of neuroendocrine differentiation are useful for the monitoring of androgen-independent disease and various bone markers are useful in patients with metastatic disease.

Topics: Aged; Alkaline Phosphatase; Androgens; Biomarkers, Tumor; Biopsy; Bone Neoplasms; Carcinoma, Neuroendocrine; Chromogranin A; Chromogranins; Collagen Type I; Disease Progression; Glycoproteins; Humans; Insulin-Like Growth Factor I; Male; Middle Aged; Neoplasm Staging; Osteoprotegerin; Peptide Fragments; Phosphopyruvate Hydratase; Prevalence; Probability; Procollagen; Prognosis; Prostate-Specific Antigen; Prostatic Neoplasms; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Testosterone; Tissue Kallikreins

Topics: Anorexia Nervosa; Biomarkers; Cardiovascular Diseases; Diabetes Mellitus; Enzyme-Linked Immunosorbent Assay; Female; Glycoproteins; Humans; Kidney Diseases; Male; Multiple Myeloma; Osteitis Deformans; Osteoprotegerin; Prostatic Neoplasms; Reagent Kits, Diagnostic; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Reference Values; Specimen Handling; Urinary Bladder Neoplasms

Metastasis to bone is a common feature in advanced prostate cancer patients. Current treatments, while effective in suppressing tumour growth and relieving tumour associated bone pain, do not provide long term remission or 'cure' for the disease. A greater understanding of prostate cancer metastasis is required if new treatment strategies are to be developed. Growth of tumour foci in skeletal sites is a major cause of morbidity in advanced prostate cancer and has required the development of specialised approaches to treatment, including the use of bisphosphonates. These drugs inhibit tumour induced osteoclastic bone resorption, thereby preventing skeletal related events and treatment induced bone loss. Zoledronic acid is currently the only bisphosphonate with proven benefit in prostate cancer. Bisphosphonates may also modify the bone microenvironment so that it becomes less favourable for the growth and survival of metastases. The most recent developments in our understanding of the advantages for growth and survival gained by metastatic prostate cancer cells in the skeleton are reviewed, along with the clinical evidence supporting the use of bisphosphonates in advanced prostate cancer.

Topics: Bone Neoplasms; Diphosphonates; Glycoproteins; Humans; Interleukin-6; Male; Osteoprotegerin; Prostatic Neoplasms; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Transforming Growth Factor beta

The most common human cancers --lung, breast and prostate -- have a great avidity for bone, leading to painful and untreatable consequences. What makes some cancers, but not others, metastasize to bone, and how do they alter its physiology? Some of the molecular mechanisms that are responsible have recently been identified, and provide new molecular targets for drug development.

Topics: Bone Neoplasms; Breast Neoplasms; Calcium; Carrier Proteins; Diphosphonates; Female; Glycoproteins; Humans; Lung Neoplasms; Male; Membrane Glycoproteins; Osteoprotegerin; Prostatic Neoplasms; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Vitamin D

Topics: Biomarkers; Bone Neoplasms; Glycoproteins; Humans; Male; Middle Aged; Osteoprotegerin; Prostatic Neoplasms; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor

p53 plays a pivotal role in controlling the differentiation of mesenchymal stem cells (MSCs) by regulating genes involved in cell cycle and early steps of differentiation process. In the context of osteogenic differentiation of MSCs and bone homeostasis, the osteoprotegerin/receptor activator of NF-κB ligand/receptor activator of NF-κB (OPG/RANKL/RANK) axis is a critical signaling pathway. The absence or loss of function of p53 has been implicated in aberrant osteogenic differentiation of MSCs that results in higher bone formation versus erosion, leading to an unbalanced bone remodeling. Here, we show by microCT that mice with p53 deletion systemically or specifically in mesenchymal cells possess significantly higher bone density than their respective littermate controls. There is a negative correlation between p53 and OPG both in vivo by analysis of serum from p53

Topics: Animals; Bone Remodeling; Cell Differentiation; Cell Line, Tumor; Humans; Male; Mesenchymal Stem Cells; Mice; Mice, Inbred C57BL; Mice, Nude; NF-kappa B; Osteogenesis; Osteoprotegerin; Osteosarcoma; Prostatic Neoplasms; Receptor Activator of Nuclear Factor-kappa B; Signal Transduction; Transcription Factor RelA; Tumor Suppressor Protein p53

Androgen deprivation therapy (ADT) for men with prostate cancer (PCa) results in accelerated bone loss and increased risk of bone fracture. The aim of the present study was to evaluate serum bone markers-sclerostin, Dickkopf-1 (DKK-1) and osteoprotegerin (OPG), in a cohort of 88 PCa patients without known bone metastases, managed with and without ADT, and to analyse their relationship with bone mineral density (BMD) and sex steroids. The cross-sectional analysis between acute-, chronic- and former-ADT groups and PCa controls showed that sclerostin and OPG levels significantly differed between them (p = 0.029 and p = 0.032). Groups contributing to these significant changes were recorded. There were no significant differences in serum DKK-1 levels across the four groups (p = 0.683). In the longitudinal analysis, significant % decreases within groups were seen for DKK-1 [chronic-ADT (- 10.06%, p = 0.0057), former-ADT (- 12.77%, p = 0.0239), and in PCa controls group (- 16.73, p = 0.0022); and OPG levels in chronic ADT (- 8.28%, p = 0.003) and PCa controls group (- 12.82%, p = 0.017)]. However, % changes in sclerostin, DKK-1, and OPG did not differ significantly over 6-months across the evaluated groups. Sclerostin levels showed significant positive correlations with BMD at baseline in the ADT group, while in PCa controls this correlation existed at both baseline and 6-month time points. Sclerostin correlated negatively with testosterone in former ADT users and in PCa controls. Possible prognostic features denoted by parallel increases in sclerostin and BMD are discussed.

Topics: Adaptor Proteins, Signal Transducing; Androgen Antagonists; Biomarkers; Bone Density; Cross-Sectional Studies; Humans; Intercellular Signaling Peptides and Proteins; Longitudinal Studies; Male; Osteoporosis; Osteoprotegerin; Prostatic Neoplasms

The cytokine system RANKL (receptor activator of NF-κB ligand), its receptor RANK and the antagonist OPG (osteoprotegerin) play a critical role in bone turnover. Our investigation was conducted to describe the gene expression at primary tumour site in prostate cancer patients and correlate the results with Gleason Score and PSA level.. Seventy-one samples were obtained from prostate cancer patients at the time of radical prostatectomy and palliative prostate resection (n = 71). Patients with benign prostate hyperplasia served as controls (n = 60). We performed real-time RT-PCR after microdissection of the samples.. The mRNA expression of RANK was highest in tumour tissue from patients with bone metastases (p < 0.001) as compared to BPH or locally confined tumours, also shown in clinical subgroups distinguished by Gleason Score (< 7 or ≥ 7, p = 0.028) or PSA level (< 10 or ≥ 10 µg/l, p = 0.004). RANKL and OPG mRNA expression was higher in tumour tissue from patients with metastatic compared to local disease. The RANKL/OPG ratio was low in normal prostate tissue and high tumours with bone metastases (p < 0.05). Expression of all three cytokines was high in BPH tissue but did not exceed as much as in the tumour tissue.. We demonstrated that RANK, RANKL and OPG are directly expressed by prostate cancer cells at the primary tumour site and showed a clear correlation with Gleason Score, serum PSA level and advanced disease. In BPH, mRNA expression is also detectable, but RANK expression does not exceed as much as compared to tumour tissue.

Topics: Aged; Aged, 80 and over; Bone Neoplasms; Humans; Kallikreins; Male; Middle Aged; Neoplasm Grading; Neoplasm Metastasis; Osteoprotegerin; Prostate-Specific Antigen; Prostatic Hyperplasia; Prostatic Neoplasms; RANK Ligand; Real-Time Polymerase Chain Reaction; Receptor Activator of Nuclear Factor-kappa B; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Transcriptome

Prostate cancer (PCa) is unique in its tendency to produce osteoblastic (OB) bone metastases. There are no existing therapies that specifically target the OB phase that affects 90% of men with bone metastatic disease. Prostatic acid phosphatase (PAP) is secreted by PCa cells in OB metastases and increases OB growth, differentiation, and bone mineralization. The purpose of this study was to investigate whether PAP effects on OB bone metastases are mediated by autocrine and/or paracrine alterations in the receptor activator of nuclear factor κ-B (RANK)/RANK ligand (RANKL)/osteoprotegerin (OPG) system. To investigate whether PAP modulated these factors and altered the bone reaction, we knocked down PAP expression in VCaP cells and stably overexpressed PAP in PC3M cells, both derived from human PCa bone metastases. We show that knockdown of PAP in VCaP cells decreased OPG while increasing RANK/RANKL expression. Forced overexpression of PAP in PC3M cells had the inverse effect, increasing OPG while decreasing RANK/RANKL expression. Coculture of PCa cells with MC3T3 preosteoblasts also revealed a role for secretory PAP in OB-PCa cross talk. Reduced PAP expression in VCaP cells decreased MC3T3 proliferation and differentiation and reduced their OPG expression. PAP overexpression in PC3M cells altered the bone phenotype creating OB rather than osteolytic lesions in vivo using an intratibial model. These findings demonstrate that PAP secreted by PCa cells in OB bone metastases increases OPG and plays a critical role in the vicious cross talk between cancer and bone cells. These data suggest that inhibition of secretory PAP may be an effective strategy for PCa OB bone lesions.

Topics: Acid Phosphatase; Animals; Bone Neoplasms; Cell Differentiation; Cell Line, Tumor; Cell Proliferation; Humans; Male; Mice; Mice, SCID; Osteoblasts; Osteoprotegerin; Prostatic Neoplasms; RANK Ligand; RNA, Small Interfering; Signal Transduction

Osteolytic bone damage is a major cause of morbidity in several metastatic pathologies. Current therapies using bisphosphonates provide modest improvement, but cytotoxic side effects still occur prompting the need to develop more effective therapies to target aggressive osteoclastogenesis. Increased levels of receptor activator of NF-κB ligand (TNFSF11/RANKL), leading to RANKL-RANK signaling, remain the key axis for osteoclast activation and bone resorption. Osteoprotegerin (TNFRSF11B/OPG), a decoy receptor for RANKL, is significantly decreased in patients who present with bone lesions. Despite its potential in inhibiting osteoclast activation, OPG also binds to TNF-related apoptosis-inducing ligand (TNFSF10/TRAIL), making tumor cells resistant to apoptosis. Toward uncoupling the events of TRAIL binding of OPG and to improve its utility for bone remodeling without inducing tumor resistance to apoptosis, OPG mutants were developed by structural homology modeling based on interactive domain identification and by superimposing models of OPG, TRAIL, and its receptor DR5 (TNFRSF10B) to identify regions of OPG for rational design. The OPG mutants were purified and extensively characterized for their ability to decrease osteoclast damage without affecting tumor apoptosis pathway both in vitro and in vivo, confirming their potential in bone remodeling following cancer-induced osteolytic damage.. OPG variants were developed that lack TRAIL binding, yet retain RANKL binding and suggest new possibilities for therapeutic targeting in osteolytic malignancies.

Topics: Animals; Apoptosis; Bone Neoplasms; Bone Remodeling; Cell Line, Tumor; Cell Proliferation; Humans; Male; Mice; Mice, Nude; Osteoclasts; Osteolysis; Osteoprotegerin; Prostatic Neoplasms; Signal Transduction; TNF-Related Apoptosis-Inducing Ligand

To develop new and effective chemopreventive agents against bone metastasis, we assessed the effects of muscadine grape skin extract (MSKE), whose main bioactive component is anthocyanin, on bone turnover, using prostate and breast cancer cell models overexpressing Snail transcription factor. MSKE has been shown previously to promote apoptosis in prostate cancer cells without affecting normal prostate epithelial cells. Snail is overexpressed in prostate and breast cancer, and is associated with increased invasion, migration and bone turnover/osteoclastogenesis. Cathepsin L (CatL) is a cysteine cathepsin protease that is overexpressed in cancer and involved in bone turnover. Snail overexpression in prostate (LNCaP, ARCaP-E) and breast (MCF-7) cancer cells led to increased CatL expression/activity and phosphorylated STAT-3 (pSTAT-3), compared to Neo vector controls, while the reverse was observed in C4-2 (the aggressive subline of LNCaP) cells with Snail knockdown. Moreover, CatL expression was higher in prostate and breast tumor tissue compared to normal tissue. MSKE decreased Snail and pSTAT3 expression, and abrogated Snail-mediated CatL activity, migration and invasion. Additionally, Snail overexpression promoted osteoclastogenesis, which was significantly inhibited by the MSKE as effectively as Z-FY-CHO, a CatL-specific inhibitor, or osteoprotegerin, a receptor activator of nuclear factor kappa B ligand (RANKL) antagonist. Overall, these novel findings suggest that Snail regulation of CatL may occur via STAT-3 signaling and can be antagonized by MSKE, leading to decreased cell invasion, migration and bone turnover. Therefore, inhibition using a natural product such as MSKE could potentially be a promising bioactive compound for bone metastatic cancer.

Topics: Animals; Anticarcinogenic Agents; Apoptosis; Bone Neoplasms; Breast Neoplasms; Cathepsin L; Cell Line, Tumor; Cell Movement; Chemoprevention; Female; Humans; Male; MCF-7 Cells; Mice; Mice, Nude; Neoplasm Invasiveness; Osteoclasts; Osteogenesis; Osteoprotegerin; Plant Extracts; Prostatic Neoplasms; RANK Ligand; Signal Transduction; Snail Family Transcription Factors; STAT3 Transcription Factor; Transcription Factors; Vitis

Receptor activator of NF-κB (RANK), RANK ligand (RANKL) and osteoprotegerin (OPG) are key regulators of bone metabolism under both normal and pathological conditions, including prostate cancer (PCa) bone metastases. However, little is known concerning the expression and function of these regulators in prostate tumor samples and PCa cells and their correlation with invasion and bone metastasis. In the present study, we determined the expression of RANK, RANKL and OPG in 3 human PCa cell lines and 40 PCa patient samples by immunohistochemistry and enzyme-linked immunosorbent assay (ELISA). As controls, samples from 20 patients with benign prostate hyperplasia (BPH) and normal prostate epithelial RWPE2 cells were also included in the analyses. The effects of soluble RANKL (sRANKL) and OPG as well as RANK knockdown on PCa invasion were examined in Transwell assays. Immunohistochemical staining detected little RANK, OPG and RANKL expression in hyperplasia prostate while the percentages of positivity were increased to 50, 45 and 52.5%, respectively, in prostate tumor tissues. OPG and sRANKL levels in the prostate tumor samples as measured by ELISA were ~10-fold that in the BPHs (P<0.01) and the levels were higher in aggressive tumors than non-aggressive ones (P<0.05). The sRANKL level in the serum of PCa patients was the same as that in the patients with BPH, yet the serum OPG levels correlated with the tissue levels (R2=0.620, P<0.01, which both showed a 10-fold increase in PCa over BPH (P<0.01) with higher levels in aggressive PCa than non-aggressive ones (P<0.05). Consistent with the tissue analyses, expression levels of RANK mRNA and protein were detected in multiple human PCa cell lines by RT-PCR and western blotting, respectively. The treatment of PCa cells with RANKL significantly increased the number of invaded cells (P<0.01), which was suppressed by the decoy receptor OPG. RANK siRNA transfection dramatically dampened the stimulatory effect of RANKL on PCa cell invasion. Our findings indicate that the expression of RANK, RANKL and OPG may be used as diagnostic markers to identify patients at high risk for aggressive PCa and that the effective suppression of PCa cell migration by OPG via the blockage of RANKL activity represents a potential therapeutic strategy for interfering with prostate tumor metastasis and progression to bone.

Topics: Adenocarcinoma; Aged; Aged, 80 and over; Biomarkers, Tumor; Bone Neoplasms; Cell Line, Tumor; Humans; Male; Middle Aged; Neoplasm Invasiveness; Osteoprotegerin; Prostatic Neoplasms; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Risk

WHAT'S KNOWN ON THE SUBJECT? AND WHAT DOES THE STUDY ADD?: There is increasing evidence that the receptor activator of nuclear factor κB ligand (RANKL) pathway not only contributes to the development of bone metastases, but also influences tumour biology in earlier stages of cancer. The study shows that preoperative serum levels of RANKL and its inhibitor osteoprotegerin (OPG) have a prognostic impact in patients undergoing radical prostatectomy for clinically localized prostate cancer. Both high levels of RANKL and a higher RANKL/OPG ratio are independent predictors of early biochemical recurrence in these patients.. To assess the prognostic impact of proteins of the receptor activator of nuclear factor κB (RANKL) pathway in serum samples from patients undergoing radical prostatectomy.. We retrospectively determined soluble RANKL (sRANKL) and osteoprotegerin (OPG) by ELISA in serum samples of 178 patients undergoing radical prostatectomy between 2004 and 2006. Clinical and patient follow-up data were analysed using the Wilcoxon-Mann-Whitney test, the Kaplan-Maier method, and single variable or multifactorial Cox proportional hazards analysis.. Higher serum sRANKL levels (P = 0.01), lower serum OPG levels (P = 0.01) and a higher sRANKL/OPG ratio (P = 0.004) were significant risk factors for biochemical recurrence (BCR). In multifactorial analysis, adjusted for the common risk factors for BCR, sRANKL and sRANKL/OPG ratio were confirmed as independent prognostic factors. Neither sRANKL nor OPG showed a clear association with histopathological factors such as pT stage, pN Gleason score or resection margin status, nor were they associated with prostate-specific antigen level.. Greater activity of the RANKL pathway in the serum of patients with prostate cancer undergoing radical prostatectomy is a risk factor for BCR. The RANKL pathway seems to contribute to the biological behaviour of prostate cancer even at the organ-confined stage of the disease.

Topics: Adult; Aged; Biomarkers, Tumor; Bone Neoplasms; Follow-Up Studies; Humans; Lymph Node Excision; Male; Middle Aged; Neoplasm Grading; Neoplasm Recurrence, Local; Osteoprotegerin; Prognosis; Prostatectomy; Prostatic Neoplasms; RANK Ligand; Retrospective Studies; Signal Transduction

New drugs that inhibit the osteoprotegerin (OPG)/receptor activator of NF-κB ligand (RANKL)/RANK pathway have demonstrated efficacy for the treatment of bone metastasis. Toxicities induced by these drugs, however, including osteonecrosis of the jaw and hypocalcemia, may adversely affect therapy. The aim of this study was to identify additional therapeutic targets that can be combined with OPG/RANKL/RANK pathway inhibition in the treatment of prostate cancer bone metastasis. We established a stable transfectant that produces high levels of OPG mRNA and protein from PC-3 human prostate cancer cells (PC3-OPG). The culture medium of PC3-OPG cells significantly inhibited the differentiation of mouse monocytes into mature osteoclasts. Furthermore, when PC3-OPG cells were injected into the bones of nude mice, bone destruction and tumor-induced osteoclast formation were reduced. Injection into bone of the mixtures containing equal amounts of green fluorescent protein (GFP)-expressing PC-3 cells (PC3-GFP) and PC3-OPG cells also reduced bone destruction, compared to the control mixture. PC3-GFP cells were subsequently isolated from bone tumors and used for microarray analysis to assess changes in gene expression following osteolytic tumor growth inhibition by OPG. We selected the top 10 upregulated genes based on results from microarrays and confirmed mRNA expression of each gene by RT-PCR. The expression patterns of retinol-binding protein 4 (RBP4) and placenta-specific 8 (PLAC8) were consistent with microarray results. Expression of these genes was also increased in the bone tumors of PC3-GFP/PC3-OPG-injected mice. Knockdown of both RBP4 and PLAC8 by siRNA inhibited the growth of PC-3 cells in vitro. Thus, RBP4 and PLAC8 may become new therapeutic targets for prostate cancer bone metastasis, in combination with OPG/RANKL/RANK pathway inhibition.

Topics: Animals; Bone Neoplasms; Cell Line, Tumor; Cell Proliferation; Disease Models, Animal; Green Fluorescent Proteins; Humans; Male; Mice; Mice, Nude; Osteoclasts; Osteolysis, Essential; Osteoprotegerin; Prostatic Neoplasms; Proteins; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Retinol-Binding Proteins, Plasma; RNA Interference; RNA, Messenger; RNA, Small Interfering

Metastatic involvement of the skeleton is a frequent consequence of advanced prostate cancer. These skeletal metastases cause a number of debilitating complications and are refractory to current treatments. New therapeutic options are being explored, including conditionally replicating adenoviruses (CRAds). CRAds are engineered to selectively replicate in and destroy tumor cells and can be 'armed' with exogenous transgenes for enhanced potency. We hypothesized that a CRAd armed with osteoprotegerin (OPG), an inhibitor of osteoclastogenesis, would inhibit the progression of prostate cancer bone metastases by directly lysing tumor cells and by reducing osteoclast activity. Although prostate cancer bone metastases are predominantly osteoblastic in nature, increased osteoclast activity is critical for the growth of these lesions. Ad5-Δ24-sOPG-Fc-RGD is a CRAd that carries a fusion of the ligand-binding domains of OPG and the Fc region of human IgG1 in place of the viral E3B genes. To circumvent low tumor cell expression of the native adenoviral receptor, an arginine-glycine-aspartic acid (RGD) peptide insertion within the viral fiber knob allows infection of cells expressing α(v) integrins. A 24-base pair deletion (Δ24) within viral E1A limits replication to cells with aberrant retinoblastoma cell cycle regulator/tumor suppressor expression. We have confirmed that Ad5-Δ24-sOPG-Fc-RGD replicates within and destroys prostate cancer cells and, in both murine and human coculture models, that infection of prostate cancer cells inhibits osteoclastogenesis in vitro. In a murine model, progression of advanced prostate cancer bone metastases was inhibited by treatment with Ad5-Δ24-sOPG-Fc-RGD but not by an unarmed control CRAd.

Topics: Adenoviridae; Analysis of Variance; Animals; Bone Neoplasms; Cell Line, Tumor; Humans; Immunoglobulin G; Luciferases; Male; Mice; Oligopeptides; Oncolytic Virotherapy; Osteoclasts; Osteoprotegerin; Prostatic Neoplasms; Real-Time Polymerase Chain Reaction; X-Ray Microtomography

The estrogen receptor (ER)β1 is successively lost during cancer progression, whereas its splice variant, ERβ2, is expressed in advanced prostate cancer. The latter form of cancer often metastasizes to bone, and we wanted to investigate whether the loss of ERβ1 and/or the expression of ERβ2 affect such signaling pathways in prostate cancer. Using PC3 and 22Rv1 prostate cancer cell lines that stably express ERβ1 or ERβ2, we found that the ERβ variants differentially regulate genes known to affect tumor behavior. We found that ERβ1 repressed the expression of the bone metastasis regulator Runx2 in PC3 cells. By contrast, RUNX2 expression was up-regulated at the mRNA level by ERβ2 in PC3 cells, whereas Slug was up-regulated by ERβ2 in both PC3 and 22Rv1 cells. In addition, the expression of Twist1, a factor whose expression strongly correlates with high Gleason grade prostate carcinoma, was increased by ERβ2. In agreement with the increased Twist1 expression, we found increased expression of Dickkopf homolog 1; Dickkopf homolog 1 is a factor that has been shown to increase the RANK ligand/osteoprotegerin ratio and enhance osteoclastogenesis, indicating that the expression of ERβ2 can cause osteolytic cancer. Furthermore, we found that only ERβ1 inhibited proliferation, whereas ERβ2 increased proliferation. The expression of the proliferation markers Cyclin E, c-Myc, and p45(Skp2) was differentially affected by ERβ1 and ERβ2 expression. In addition, nuclear β-catenin protein and its mRNA levels were reduced by ERβ1 expression. In conclusion, we found that ERβ1 inhibited proliferation and factors known to be involved in bone metastasis, whereas ERβ2 increased proliferation and up-regulated factors involved in bone metastasis. Thus, in prostate cancer cells, ERβ2 has oncogenic abilities that are in strong contrast to the tumor-suppressing effects of ERβ1.

Topics: Animals; Bone Neoplasms; Cell Line, Tumor; Cell Proliferation; Core Binding Factor Alpha 1 Subunit; Estrogen Receptor beta; Humans; Intercellular Signaling Peptides and Proteins; Male; Mice; Mice, Nude; Neoplasm Metastasis; Nuclear Proteins; Osteoclasts; Osteoprotegerin; Prostatic Neoplasms; Protein Isoforms; RANK Ligand; RNA, Messenger; Signal Transduction; Snail Family Transcription Factors; Transcription Factors; Transcriptional Activation; Twist-Related Protein 1

We aimed to assess the diagnostic accuracy of serum osteoclastogenesis markers for detection of bone metastasis in patients with prostate cancer (PCa) and to assess the usefulness of these markers as predictors of mortality from PCa.. Serum osteoprotegerin (OPG) and receptor activator of nuclear factor κB ligand (RANKL) levels were measured in 201 patients (51 with bone metastasis, 55 with T2M0 PCa, 46 with T3M0 PCa, and 49 without PCa). Multivariate stepwise logistic regression analysis was used to identify independent predictors of bone metastasis. Correlation of serum marker levels with bone metastasis was assessed using receiver operating characteristics (ROC) analysis. Multivariate Cox proportional hazards analysis was used to predict cause-specific survival in PCa patients with bone metastasis.. Serum OPG and prostate-specific antigen levels were significantly elevated in patients with bone metastasis. Multivariate stepwise logistic regression analysis demonstrated that serum OPG levels were significant predictors of bone metastasis. ROC analyses showed that serum OPG levels were the most reliable predictor of bone metastasis (area under the curve = 0.68). Multivariate Cox proportional hazards analysis revealed that only serum OPG and extent of disease on bone scan (EOD) >3 were independent prognostic factors for PCa-related death. On the other hand, serum RANKL levels were not significant predictors of bone metastasis and could not predict survival probability in PCa patients with bone metastasis.. Serum OPG was a more reliable marker than serum RANKL in detecting bone metastatic spread and in predicting survival probability in PCa patients with bone metastasis.

Topics: Aged; Aged, 80 and over; Biomarkers, Tumor; Bone Neoplasms; Humans; Japan; Male; Middle Aged; Neoplasm Staging; Osteoprotegerin; Prostatic Neoplasms; RANK Ligand; Survival Analysis

Vitamin D is considered as an important determinant of bone turnover as well as cancer growth. Using a murine model of bone metastasis, we investigated the effect of vitamin D deficiency on prostate cancer cell growth in bone.. Three-week-old male nude mice were fed either normal chow (control) or a diet deficient in vitamin D. The latter diet resulted in severe hypovitaminosis D within 6 weeks. At this point of time, 5 × 10(4)  cells of the prostate cancer cell line, PC-3, were injected either into the bone marrow (tibia) or subcutaneously into soft tissues. Osteoprotegerin (OPG) was co-administered in subgroups of mice to suppress bone remodeling. Osteolytic lesions were monitored by serial X-ray, while soft tissue tumor growth was measured by caliper. All tissues were analyzed by micro-CT and histology at endpoint.. Bone turnover was significantly accelerated in vitamin D deficient compared to vitamin D sufficient mice from week 6 onwards. Intra-tibially implanted PC-3 cells resulted in mixed osteolytic and osteosclerotic lesion. At endpoint, osteolytic and osteosclerotic lesion areas, total tumor area, and tumor mitotic activity were all significantly increased in vitamin D deficient mice compared to controls. Regardless of diet, OPG reduced bone turnover, total tumor, and osteosclerotic area as well as tumor mitotic activity, while promoting cell apoptosis. In contrast, vitamin D deficiency did not alter tumor growth in soft tissues.. Vitamin D deficiency stimulates prostate cancer growth in bone through modulating the bone microenvironment.

Topics: Acid Phosphatase; Animals; Bone Neoplasms; Bone Remodeling; Calcitriol; Cell Line, Tumor; Histocytochemistry; Isoenzymes; Male; Mice; Mice, Inbred BALB C; Mice, Nude; Osteoprotegerin; Peptide Fragments; Procollagen; Prostatic Neoplasms; Specific Pathogen-Free Organisms; Tartrate-Resistant Acid Phosphatase; Tomography, X-Ray Computed; Vitamin D; Vitamin D Deficiency

Bone metastases are the most critical complication of prostate cancer (PCa), resulting in severe morbidity and mortality. Tumor necrosis factor receptor superfamily member 11b (TNFRSF11B) is a critical regulator between PCa cells and the bone environment. Recently, TNFRSF11B rs10505346 has been implicated in PCa risk in the Cancer Genetic Markers of Susceptibility genomewide association study. However, the association between this variant and biochemical failure in PCa patients receiving radical prostatectomy (RP) has not been determined.. Associations of TNFRSF11B rs10505346 with age at diagnosis, preoperative prostate-specific antigen (PSA) level, Gleason score, pathologic stage, surgical margin, and PSA recurrence were evaluated in a cohort of 314 localized PCa patients receiving RP. The prognostic significance on PSA recurrence was assessed by Kaplan-Meier analysis and Cox regression model.. The mean level of preoperative PSA and the relative risks of PSA recurrence after RP were lower in individuals with T allele than in those with the G allele at TNFRSF11B rs10505346 (P = 0.019 and 0.014, respectively). The T allele of rs10505346 remained a protective factor against PSA recurrence (P = 0.022) in multivariate Cox regression model after considering all clinicopathological risk factors except PSA level.. Our data suggest that TNFRSF11B rs10505346 is associated with PSA level and might be a prognostic factor for the recurrence of PSA in PCa patients receiving RP.

Topics: Aged; Alleles; Biomarkers, Tumor; Cohort Studies; Disease Progression; Humans; Kaplan-Meier Estimate; Male; Neoplasm Staging; Osteoprotegerin; Polymorphism, Genetic; Predictive Value of Tests; Preoperative Care; Prognosis; Proportional Hazards Models; Prostatectomy; Prostatic Neoplasms

Hematopoietic growth factors are used to reverse chemotherapy-induced leukopenia. However, some factors such as granulocyte macrophage colony-stimulating factor (GM-CSF) induce osteoclast-mediated bone resorption that can promote cancer growth in the bone. Accordingly, we evaluated the ability of GM-CSF to promote bone metastases of breast cancer or prostate cancer in a mouse model of chemotherapy-induced leukopenia. In this model, GM-CSF reversed cyclophosphamide-induced leukopenia but also promoted breast cancer and prostate cancer growth in the bone but not in soft tissue sites. Bone growth was associated with the induction of osteoclastogenesis, yet in the absence of tumor GM-CSF, it did not affect osteoclastogenesis. Two osteoclast inhibitors, the bisphosphonate zoledronic acid and the RANKL inhibitor osteoprotegerin, each blocked GM-CSF-induced tumor growth in the bone but did not reverse the ability of GM-CSF to reverse chemotherapy-induced leukopenia. Our findings indicate that it is possible to dissociate the bone-resorptive effects of GM-CSF, to reduce metastatic risk, from the benefits of this growth factor in reversing leukopenia caused by treatment with chemotherapy.

Topics: Animals; Antineoplastic Agents, Alkylating; Bone Density Conservation Agents; Bone Neoplasms; Breast Neoplasms; Cyclophosphamide; Diphosphonates; Female; Granulocyte-Macrophage Colony-Stimulating Factor; Humans; Imidazoles; Leukopenia; Male; Mice; Mice, Nude; Osteoclasts; Osteoprotegerin; Prostatic Neoplasms; RANK Ligand; Zoledronic Acid

Glucocorticoids (GCs) are widely used for the treatment of hormone refractory prostate cancer. However, few data are available on the expression and regulation of glucocorticoid and mineralocorticoid receptors (GR and MR) and 11beta-hydroxysteroid dehydrogenase (11beta-HSD) 1 and -2 activities in prostate cancer cells. Here we show that GR is expressed in both the androgen-independent PC-3 cell line and, at very low levels, in the androgen-dependent LNCaP cells, and MR is expressed in both cell lines. IL-1beta increased GR expression in both cell lines. In LNCaP cells IL-1beta also increased MR expression. Significant 11beta-HSD oxidase activity and 11beta-HSD2 protein were found in LNCaP cells, but not in PC3 cells, and no ketoreductase activity was detected in either cell lines. GR function was assessed by measuring the inhibitory effect of dexamethasone on constitutive and IL-1beta-inducible IL-6 and osteoprotegerin (OPG) production. In PC-3 cells, IL-1beta stimulated IL-6 and OPG release, and dexamethasone dose-dependently inhibited IL-1beta-inducible IL-6 release, and constitutive and IL-1beta-inducible OPG release. In LNCaP cells, IL-1beta stimulated only OPG release. While dexamethasone was ineffective, cortisol dose-dependently inhibited IL-1beta-inducible OPG release. Eplerenone (Epl), a selective mineralocorticoid antagonist, reverted this effect. We conclude that different patterns of expression of receptors and 11beta-HSD activity were associated with different responsiveness to GCs in terms of regulated gene expression. GR and MR expression may vary as a function not only of the malignant phenotype, but also of local conditions such as the degree of inflammation. Inhibition of IL-6 and OPG release by GCs may contribute to the antitumor efficacy in prostate cancer.

Topics: 11-beta-Hydroxysteroid Dehydrogenase Type 1; 11-beta-Hydroxysteroid Dehydrogenase Type 2; Androgens; Antineoplastic Agents; Cell Line, Tumor; Glucocorticoids; Humans; Interleukin-1beta; Male; Osteoprotegerin; Prostatic Neoplasms; Receptors, Glucocorticoid; Receptors, Mineralocorticoid

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

Prostate cancer (PCa) has a high propensity to metastasize to the bone. PCa cells produce several bone-related factors, namely parathyroid hormone related protein (PTHrP), its PTH type 1 receptor (PTH1R), osteoprotegerin (OPG), and receptor activator of NF-kappa B ligand (RANKL). The effects of these factors might explain, at least in part, the ability of PCa cells to grow in and interact with bone.. We first analyzed the expression of the aforementioned factors (by western blot and flow cytometry), and their modulation by the phytoestrogens genistein and daidzein (as potential anti-tumoral agents), in human PCa cells in vitro. We also assessed the impact of these osteomimetic factors on PCa cell viability (by propidium iodide staining and flow cytometry, and trypan blue staining).. Genistein and daidzein, at nM range, increased both the PTHrP/PTH1R system and the OPG/RANKL protein ratio, while genistein and, to a lesser extent, daidzein, at >microM doses, inhibited cell viability in PCa cells. Both N- and C-terminal domains of PTHrP inhibited genistein-induced cell death by modulating transcription factor Runx-2 and the Bcl-2/Bax protein ratio in PCa cells.. Our findings indicate that high doses of genistein and daidzein cause PCa cell death. On the other hand, low doses of these phytoestrogens induce some osteomimetic features in PCa cells with putative impact on PCa development.

Topics: Blotting, Western; Bone and Bones; Cell Death; Cell Line, Tumor; Cell Survival; Cytokines; Flow Cytometry; Genistein; Humans; Isoflavones; Male; Osteoprotegerin; Parathyroid Hormone-Related Protein; Phytoestrogens; Prostatic Neoplasms; RANK Ligand; Receptor, Parathyroid Hormone, Type 1; Reverse Transcriptase Polymerase Chain Reaction; RNA, Neoplasm; Transfection

Osteoprotegerin (OPG) expression participates in the pathophysiology of osteoblastic metastasis in prostate cancer.. We investigated whether the expression of OPG of PC-3 prostate cancer cells grown in 3-D collagen gels is stimulated by co-culture with MG-63 osteoblast-like cells. The expression of Runx2 (Cbfa1) and OPG were assessed by reverse transcription-polymerase chain reaction and Western blot analysis.. OPG and Runx2 were expressed in both PC-3 and MG-63 cells. OPG expression was remarkably enhanced in PC-3 cells grown in co-culture with MG-63 cells in a time-dependent manner. Runx2 expression of PC-3 cells was not altered by their co-culture with MG-63 cells. OPG expression of PC-3 cells was altered neither by insulin-like growth factor I (IGF-1), transforming growth factor beta1 (TGFbeta1), interleukin 6 (IL-6) nor by dexamethasone and zoledronic acid exogenously added to PC-3 cells.. The enhancement of the OPG expression in PC-3 cells by MG-63 cells is not mediated by IGF-1, IL-6 and TGFbeta1.

Topics: Bone Neoplasms; Cell Communication; Coculture Techniques; Core Binding Factor Alpha 1 Subunit; Humans; Insulin-Like Growth Factor I; Interleukin-6; Male; Osteoblasts; Osteoprotegerin; Osteosarcoma; Prostatic Neoplasms; Transforming Growth Factor beta1

Current evidence indicates that an osteoblast lesion in prostate cancer is preceded by osteolysis. Thus, prevention of osteolysis would reduce complications of bone metastasis. Bone marrow-derived mesenchymal stem cells have the ability to differentiate into osteoblast and produce osteoprotegerin, a decoy receptor for the receptor activator for nuclear factor kappaB ligand, naturally. The present study examined the potential of unmodified mesenchymal stem cells to prevent osteolytic bone lesions in a preclinical mouse model of prostate cancer.. The human prostate cancer cell line PC3 was implanted in tibiae of severe combined immunodeficient mice. After establishment of the tumor, either unmodified or genetically engineered mesenchymal stem cells overexpressing osteoprotegerin was injected at the site of tumor growth. The effects of therapy were monitored by bioluminescence imaging, micro-computed tomography, immunohistochemistry, and histomorphometry.. Data indicated significant (P < 0.001) inhibition of tumor growth and restoration of bone in mice treated with unmodified and modified mesenchymal stem cells. Detailed analysis suggested that the donor mesenchymal stem cell inhibited tumor progression by producing woven bone around the growing tumor cells in the tibiae and by preventing osteoclastogenesis.. Overcoming the limitation of the number of mesenchymal stem cells available in the bone can provide significant amelioration for osteolytic damage without further modification.

Topics: Animals; Bone Marrow Cells; Cell Line, Tumor; Cell- and Tissue-Based Therapy; Humans; Immunohistochemistry; Male; Mesenchymal Stem Cells; Mice; Mice, SCID; Neoplasm Metastasis; Osteoclasts; Osteoprotegerin; Prostatic Neoplasms; Tibia; X-Ray Microtomography

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.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Bone Neoplasms; Cell Line, Tumor; Cell Proliferation; Docetaxel; Humans; Male; Mice; Mice, Nude; Osteolysis; Osteoprotegerin; Prostatic Neoplasms; RANK Ligand; Receptors, Fc; Survival Analysis; Taxoids; Tumor Burden; Whole Body Imaging; Xenograft Model Antitumor Assays

The purpose of this study was to evaluate the role of osteoprotegerin gene (OPG) polymorphisms as genetic modifiers in the etiology of prostate cancer (PCa) and disease progression.. Three hundred and sixty one patients with PCa and 195 normal controls were enrolled in the study, and two genetic polymorphisms, 149 T/C and 950 T/C in the putative promoter region of OPG, were genotyped.. There was no significant difference in the genotype frequencies between PCa patients and controls (P = 0.939 and 0.294 for 149 T/C and 950 T/C polymorphisms, respectively). However, those patients with TC and TT genotypes in the 950 T/C polymorphism had a significantly increased risk of extraprostatic (age-adjusted odds ratio; aOR = 1.74 and 2.03 for TC and TT genotypes compared with the CC genotype, P = 0.028) and metastatic disease (aOR = 1.72 and 2.76 for TC and TT genotypes compared with the CC genotype, P = 0.009) compared with those with the CC genotype. In addition, analysis of the metastatic PCa patients (Stage D) showed that the presence of the T allele of the OPG 950 T/C polymorphism was an independent risk factor predicting survival by Cox proportional hazard regression analyses (P = 0.031).. Progression of PCa may be influenced by an intrinsic genetic factor of the host's bone metabolism. The variant C allele of 950 T/C in the OPG promoter may play a major role as a genetic safe guard against progression in patients with PCa.

Topics: Aged; Case-Control Studies; Disease Progression; Genetic Predisposition to Disease; Genotype; Humans; Male; Middle Aged; Models, Genetic; Odds Ratio; Osteoprotegerin; Polymorphism, Genetic; Promoter Regions, Genetic; Prostatic Neoplasms; Risk

Bone forming metastases are a common and disabling consequence of prostate cancer (CaP). The potential role of osteoclast activity in CaP bone metastases is not completely explained. In this study, we investigated ex vivo whether the osteolytic activity is present and how it is ruled in CaP patients with bone forming metastases.. Forty-six patients affected by newly diagnosed CaP and healthy controls were enrolled. At diagnosis, 37 patients had a primary tumour only, while 9 had primary tumour and concomitant bone forming metastases. In all patients there was no evidence of metastasis to other non-bone sites. For all patients and controls we collected blood and urinary samples. We evaluated patients' bone homeostasis; we made peripheral blood mononuclear cell (PBMC) cultures to detect in vitro osteoclastogenesis; we dosed serum expression of molecules involved in cancer induced osteoclatogenesis, such as RANKL, OPG, TNF-alpha, DKK-1 and IL-7. By Real-Time PCR, we quantified DKK-1 and IL-7 gene expression on micro-dissected tumour and healthy tissue sections.. CaP bone metastatic patients showed bone metabolism disruption with increased bone resorption and formation compared to non-bone metastatic patients and healthy controls. The CaP PBMC cultures showed an enhanced osteoclastogenesis in bone metastatic patients, due to an increase of RANKL/OPG ratio. We detected increased DKK-1 serum levels and tissue gene expression in patients compared to controls. IL-7 resulted high in patients' sera, but its tissue gene expression was comparable in patients and controls.. We demonstrated ex vivo that osteoclastogenesis is an active mechanism in tumour nesting of bone forming metastatic cancer and that serum DKK-1 levels are increased in CaP patients, suggesting to deeply investigate its role as tumour marker.

Topics: Aged; Bone Neoplasms; Bone Remodeling; Bone Resorption; Carcinoma; Case-Control Studies; Cell Differentiation; Cells, Cultured; Cross-Sectional Studies; Gene Expression Regulation, Neoplastic; Humans; Intercellular Signaling Peptides and Proteins; Interleukin-7; Male; Middle Aged; Osteoclasts; Osteoprotegerin; Prostatic Neoplasms; RANK Ligand

Metastases to bone are a frequent complication of human prostate cancer and result in the development of osteoblastic lesions that include an underlying osteoclastic component. Previous studies in rodent models of breast and prostate cancer have established that receptor activator of NF-kappaB ligand (RANKL) inhibition decreases bone lesion development and tumor growth in bone. RANK is essential for osteoclast differentiation, activation, and survival via its expression on osteoclasts and their precursors. RANK expression has also been observed in some tumor cell types such as breast and colon, suggesting that RANKL may play a direct role on tumor cells.. Male CB17 severe combined immunodeficient (SCID) mice were injected with PC3 cells intratibially and treated with either PBS or human osteprotegerin (OPG)-Fc, a RANKL antagonist. The formation of osteolytic lesions was analyzed by X-ray, and local and systemic levels of RANKL and OPG were analyzed. RANK mRNA and protein expression were assessed on multiple prostate cancer cell lines, and events downstream of RANK activation were studied in PC3 cells in vitro.. OPG-Fc treatment of PC3 tumor-bearing mice decreased lesion formation and tumor burden. Systemic and local levels of RANKL expression were increased in PC3 tumor bearing mice. PC3 cells responded to RANKL by activating multiple signaling pathways which resulted in significant changes in expression of genes involved in osteolysis and migration. RANK activation via RANKL resulted in increased invasion of PC3 cells through a collagen matrix.. These data demonstrate that host stromal RANKL is induced systemically and locally as a result of PC3 prostate tumor growth within the skeleton. RANK is expressed on prostate cancer cells and promotes invasion in a RANKL-dependent manner.

Topics: Animals; Bone Neoplasms; Cell Line, Tumor; Cell Movement; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Humans; Male; Mice; Mice, SCID; Neoplasm Transplantation; Osteolysis; Osteoprotegerin; Prostatic Neoplasms; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; RNA, Messenger; Signal Transduction

Factors that regulate the induction of apoptosis of tumour cells are potential candidates for therapeutic intervention for the majority of cancers. Studying modifiers of apoptotic responses, such as members of the tumour necrosis factor receptor superfamily, may give clues as to how induction of apoptosis in tumours could be maximized to enhance the benefit of treatment regimes. Tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising anti-tumour molecule since its activity is specific for tumour cell populations. TRAIL binds to death receptors, inducing apoptosis in susceptible cells. The mechanisms which determine whether tumour cells are susceptible to TRAIL are unclear, and several mechanisms have been proposed, including expression of osteoprotegerin (OPG), decoy receptors, and factors that affect intracellular signalling of pro-apoptotic molecules, such as c-FLIP. Here we show that experiments to modulate the activity of one of these factors, OPG, by over-expression and also by stable knockdown of OPG expression, alters the TRAIL sensitivity of PC3 prostate cancer cells. However we show that some observed effects, which appear to support the hypothesis that OPG prevents TRAIL-induced apoptosis of tumour cells, may be due to variation of the TRAIL response of sub-clones of tumour cells, even within a cloned population. These results highlight potential limitations of experiments designed to test contribution of factors affecting intrinsic apoptosis susceptibility using cloned tumour cell populations.

Topics: Apoptosis; Apoptosis Regulatory Proteins; Cell Line, Tumor; Clone Cells; Drug Resistance, Neoplasm; Gene Expression Regulation; Humans; Male; Osteoprotegerin; Phenotype; Prostatic Neoplasms; TNF-Related Apoptosis-Inducing Ligand

To investigate multiple bone cytokines produced by prostate carcinoma (PCa) as a novel strategy to differentiate potential aggressiveness in localised PCa using immunohistochemical analysis.. A total of 47 cases of PCa undergoing radical prostatectomy or transurethral prostatic resection at our institution (Fundación Jiménez Díaz (Grupo Capio), Madrid, Spain) between January 1991 and June 1998 were identified as low-grade (< or =4; n = 22) or high-grade (> or =7, excluding 7 (3+4) cases; n = 25) PCa according to Gleason grade. PCa specimens were immunostained for: parathyroid hormone (PTH)-related protein (PTHrP), the PTH1 receptor, osteoprotegerin and receptor activator of nuclear factor-kappa B ligand (RANKL), as well as Ki67 (a proliferation marker) and CD34 (an angiogenesis marker).. PCa samples showed an increased immunostaining for both osteoprotegerin and RANKL, associated with tumour grade and PTHrP positivity, in the tumoral epithelium. Using a score value of 4-corresponding to moderate staining - as cut-off, the best sensitivity value was for PTHrP (with C-terminal antiserum C6; 100 %); wheras the best specificity value was for RANKL (95 %).. All the evaluated factors are overexpressed mainly in the high-grade tumours. Our findings indicate that, in most patients with PCa (with Ki67 values between 1% and 9%), sequential determination of C-terminal PTHrP and RANKL immunoreactivities is a useful approach to discriminate low-grade and high-grade tumours.

Topics: Aged; Aged, 80 and over; Antigens, CD34; Biomarkers, Tumor; Humans; Immunoenzyme Techniques; Ki-67 Antigen; Male; Middle Aged; Neoplasm Proteins; Osteoprotegerin; Parathyroid Hormone-Related Protein; Prostatectomy; Prostatic Neoplasms; Receptor Activator of Nuclear Factor-kappa B; Receptor, Parathyroid Hormone, Type 1; Retrospective Studies; Sensitivity and Specificity

Osteoprotegerin (OPG), a key regulator of bone resorption, is hypothesized to have a role in prostate cancer (CaP) bone metastasis. As advanced CaP is treated by androgen ablation, we examined if androgen modulates OPG expression by CaP cell lines in vitro. Basal levels of secreted OPG protein were significantly greater in androgen-independent PC-3 cells compared with androgen-responsive LNCaP-FGC cells (P<0.001); OPG was not detected in the androgen-responsive CaP cell lines LAPC-4 or DuCaP. Treatment with 5alpha-dihydrotestosterone (5alpha-DHT) significantly decreased OPG protein levels in both PC-3 and LNCaP-FGC, with maximal suppression using 10(-9)-10(-7) M 5alpha-DHT in PC-3 (P<0.01; day 3), and using 10(-10)-10(-9) M 5alpha-DHT in LNCaP-FGC cells (P<0.01; day 6). OPG messenger RNA levels were not significantly altered by this 5alpha-DHT treatment. Co-treatment with 10(-6) M flutamide blocked 5alpha-DHT inhibition of OPG protein expression in LNCaP-FGC cells. These data suggest that androgen may modulate OPG protein levels in CaP cell lines in vitro using a post-transcriptional mechanism.

Topics: 5-alpha-Dihydroprogesterone; Androgens; Cell Line, Tumor; Flutamide; Gene Expression; Humans; Male; Osteoprotegerin; Prostatic Neoplasms; RNA, Messenger

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.

Topics: 3T3 Cells; Animals; Bone Neoplasms; Cell Line, Tumor; Culture Media, Conditioned; Humans; I-kappa B Proteins; Male; MAP Kinase Signaling System; Mice; Models, Biological; Osteoblasts; Osteoclasts; Osteoprotegerin; Prostatic Neoplasms; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Recombinant Proteins; Signal Transduction; STAT3 Transcription Factor

The role of receptor activator of nuclear factor-kappaB ligand (RANKL)/osteoprotegerin (OPG) system, and osteopontin (OPN) was studied in patients with solid tumors metastatic to the bone in relation to the type of malignancy and the neoplastic burden to the skeleton. Levels of soluble RANKL (sRANKL), OPG and OPN were assessed in 61 patients with breast, lung and prostate cancer with newly-diagnosed metastasis to the bone, in parallel with bone resorption [C-telopeptide of type-I collagen (CTX), tartrate-resistant acid phosphatase-5b (TRACP-5b)] and bone formation markers [bone-alkaline phosphatase (bALP), osteocalcin (OC), and C-terminal propeptide of collagen type-I (CICP)]. Patients had elevated serum levels of sRANKL, OPG, OPN, TRACP-5b, and bALP, and reduced OC levels compared to controls. OPG correlated with the extent of metastatic bone burden. Patients with breast and lung cancer shared increased levels of sRANKL, OPG, and OPN whereas prostate cancer patients had elevated values of OPG and bALP only. These results suggest that patients with solid tumors metastatic to the bone have severe disruption of the sRANKL/OPG axis. Breast and lung cancer seem to exert their osteolytic action through upregulation of the sRANKL/OPG system and OPN, whereas prostate cancer seems to provoke profound elevation of OPG levels only, thus leading to increased osteoblastic activity.

Topics: Adult; Aged; Aged, 80 and over; Biomarkers, Tumor; Bone and Bones; Bone Neoplasms; Bone Remodeling; Breast Neoplasms; Down-Regulation; Female; Humans; Lung Neoplasms; Male; Osteoblasts; Osteopontin; Osteoprotegerin; Prostatic Neoplasms; RANK Ligand; Skeleton; Up-Regulation

To evaluate the diagnostic usefulness of serum osteoprotegerin (OPG) in prostate cancer bone metastasis.. Serum osteoprotegerin were measured by ELISA assay in 30 healthy men, 30 patients with benign prostatic hyperplasia, 66 patients with prostate cancer including 36 without bone metastasis (30 with localized cancer, 6 with lymph node metastasis) and 30 with bone metastasis. The results associated with clinical data were calculated statistically.. Serum osteoprotegerin were significantly increased in patients with bone metastasis compared with others (P<0.001). OPG level had a positive correlation with either prostate specific antigen (PSA) or Alkaline phosphatase (ALP) level (r=0.427, 0.277; P<0.001); and a positive correlation with either Gleason score or grade (r=0.427, 0.277; P<0.001). ROC analysis proved that OPG had better diagnostic accuracy than ALP for detecting bone metastasis in prostate cancer.. Serum osteoprotegerin could be used as a marker for diagnosis of bone metastasis in prostate cancer.

Topics: Biomarkers, Tumor; Bone Neoplasms; Humans; Male; Osteoprotegerin; Prostatic Neoplasms; Sensitivity and Specificity

As advanced prostate cancers are resistant to currently available chemotherapies, we evaluated the cytotoxic effect of TNF-related apoptosis-inducing ligand (TRAIL) and characterized the involvement of its five receptors DR4, DR5, DcR1, DcR2, and osteoprotegerin (OPG) and of the death-inducing signaling complex (DISC)-forming proteins caspase 8 and c-FLIP in prostate cell lines.. We used six prostate cell lines, each corresponding to a particular stage in prostate tumorigenesis, and analyzed TRAIL sensitivity in relation to TRAIL receptors' expression.. TRAIL sensitivity was correlated with tumor progression and DR5 expression levels and apoptosis was exclusively mediated by DR5. DcR2 was significantly more abundant in tumor cells than in non-neoplastic ones and may contribute to partial resistance to TRAIL in some prostate tumor cells. Conversely, non-tumoral cells secreted high levels of OPG, which can protect them from apoptosis. Finally, caspase 8 expression levels were as DR5 directly correlated to TRAIL sensitivity in prostate tumor cells.. TRAIL-induced apoptosis is closely related to the balanced expression of its different receptors in prostate cancer cells and their modulation could be of potential clinical value for advanced tumor treatment.

Topics: Androgens; Antineoplastic Agents; Apoptosis; Apoptosis Regulatory Proteins; CASP8 and FADD-Like Apoptosis Regulating Protein; Caspase 8; Caspases; Cell Line; Cell Line, Tumor; Death Domain Receptor Signaling Adaptor Proteins; Disease Progression; Drug Screening Assays, Antitumor; Gene Expression Regulation, Neoplastic; Glycoproteins; Humans; Intracellular Signaling Peptides and Proteins; Male; Membrane Glycoproteins; Neoplasm Staging; Osteoprotegerin; Prostate; Prostatic Neoplasms; Receptors, Cytoplasmic and Nuclear; Receptors, TNF-Related Apoptosis-Inducing Ligand; Receptors, Tumor Necrosis Factor; RNA, Messenger; Signal Transduction; TNF-Related Apoptosis-Inducing Ligand; Tumor Necrosis Factor Decoy Receptors; Tumor Necrosis Factor Receptor-Associated Peptides and Proteins; Tumor Necrosis Factor-alpha

Metastatic bone disease is one of the major causes of morbidity and mortality in prostate cancer patients. Bisphosphonates are currently used to inhibit bone resorption and reduce tumor-induced skeletal complications. More effective bisphosphonates would enhance their clinical value.. We tested several bisphosphonates in a green fluorescent protein (GFP)-expressing human prostate cancer nude mouse model. The in vivo effects of four bisphosphonates, including pamidronate, etidronic acid, and olpadronate, on bone tumor burden in mice intratibially inoculated with PC-3-GFP human prostate cancer cells were visualized by whole-body fluorescence imaging and X-ray.. The PC-3-GFP cells produced extensive bone lesions when injected into the tibia of immunocompromised mice. The skeletal progression of the PC-3-GFP cell growth was monitored by GFP fluorescence and the bone destruction was evaluated by X-ray. We showed that 3,3-dimethylaminopropane-1-hydroxy-1,1-diphosphonic acid (olpadronate) was the most effective bisphosphonate treatment in reducing tumor burden as assessed by GFP imaging and radiography. The GFP tumor area and X-ray score significantly correlated. Reduced tumor growth in the bone was accompanied by reduced serum calcium, parathyroid hormone-related protein, and osteoprotegerin.. The serum calcium, parathyroid hormone-related protein, and osteoprotegerin levels were significantly correlated with GFP area and X-ray scores. Treatment with olpadronate reduced tumor growth in the bone measured by GFP and X-ray imaging procedures. Imaging of GFP expression enables monitoring of tumor growth in the bone and the GFP results complement the X-ray assessment of bone disease. The data in this report suggest that olpadronate has potential as an effective inhibitor of the skeletal progression of clinical prostate cancer.

Topics: Animals; Bone Density Conservation Agents; Bone Neoplasms; Calcium; Cell Line, Tumor; Diphosphonates; Disease Progression; Glycoproteins; Green Fluorescent Proteins; Humans; Male; Mice; Mice, Nude; Osteoprotegerin; Pamidronate; Parathyroid Hormone-Related Protein; Prostatic Neoplasms; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Time Factors; Treatment Outcome; Xenograft Model Antitumor Assays

Bone metastasis is very common in advanced prostate cancer. Docetaxel has been shown to improve survival in patients with metastatic prostate cancer. However, treatment with docetaxel is associated with a certain degree of toxicity. Genistein, derived from soybeans, has been found to inhibit cancer cell growth without toxicity. We have recently reported that genistein could potentiate the antitumor activity of chemotherapeutic agents both in vitro and in vivo. However, the molecular mechanism of this novel effect of genistein has not been fully elucidated. In this study, we found that genistein significantly potentiated the antitumor, anti-invasive, and antimetastatic activities of docetaxel both in culture and in severe combined immunodeficient (SCID)-human model of experimental prostate cancer bone metastasis. We further conducted microarray analysis, real-time reverse transcription-PCR, Western blot analysis, small interfering RNA and cDNA transfection, matrix metalloproteinase-9 (MMP-9) activity assay, and invasion assay. We found that the expression of osteoprotegerin (OPG) was induced by genistein and inhibited by docetaxel, whereas genistein significantly down-regulated the expression and secretion of receptor activator of nuclear factor-kappaB (RANK) ligand (RANKL) and inhibited osteoclast formation. Moreover, genistein down-regulated the expression and activity of MMP-9, which was induced by docetaxel treatment, and inhibited invasion of PC-3 cells. These results suggest that the observed potentiation of antitumor activity of docetaxel by genistein in the SCID-human model of experimental bone metastasis could be mediated by regulation of OPG/RANK/RANKL/MMP-9 signaling, resulting in the inhibition of osteoclastic bone resorption and prostate cancer bone metastasis. From these results, we conclude that genistein could be a promising nontoxic agent to improve the treatment outcome of metastatic prostate cancer with docetaxel.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Bone Neoplasms; Carrier Proteins; Cell Growth Processes; Cell Line, Tumor; Docetaxel; Down-Regulation; Drug Synergism; Genistein; Glycoproteins; Humans; Male; Matrix Metalloproteinase 9; Matrix Metalloproteinase Inhibitors; Membrane Glycoproteins; Mice; Mice, SCID; NF-kappa B; Osteoprotegerin; Prostatic Neoplasms; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; RNA, Messenger; RNA, Small Interfering; Signal Transduction; Taxoids; Xenograft Model Antitumor Assays

Late-stage prostate cancer patients are refractory to hormone therapy and exhibit a high propensity to develop skeletal metastasis. In this regard, the role of a novel cytokine system belonging to the tumor necrosis factor (TNF) family that is critical for osteoclastic osteolysis and that consists of receptor activator of NF-kappaB ligand (RANKL), its receptor (RANK), and decoy receptor osteoprotegerin (OPG) is of potential interest.. Reverse-transcriptase polymerase chain reaction (RT-PCR) and immunohistochemical analysis was used to examine the expression of RANKL, RANK, and OPG in human prostate cancer cell lines and in 89 archival samples of primary and metastatic (lymph nodes, skeleton) prostate cancer patients. Expression of these proteins was correlated with clinicopathogic parameters of the prostate cancer.. Expression of RANKL/RANK/OPG was low in normal but markedly higher in prostate cancer cell lines. Analysis of surgical biopsy specimens showed the expression of RANKL (31%), RANK (38%), and OPG (19%) in primary carcinoma. The expression frequency was significantly higher (RANKL [44%], RANK [49%], and OPG [73%]) in metastatic prostate cancer. OPG (83%) production was more common in skeletal as compared with lymph node metastases (46%), whereas the expression of RANKL expression was less discordant in bone (47%) and lymph node metastases (36%). The increased expression of RANKL/RANK/OPG observed correlated with Gleason score, TNM stage, androgen status, and serum prostate-specific antigen (PSA) levels in the prostate cancer patients.. Expression of RANKL/RANK/OPG correlates with more aggressive, advanced, metastatic prostate carcinoma to suggest their role as diagnostic, prognostic, and therapeutic targets for prostate cancer.

Topics: Aged; Biomarkers, Tumor; Carcinoma; Carrier Proteins; Glycoproteins; Humans; Male; Membrane Glycoproteins; Middle Aged; Neoplasm Metastasis; Neoplasm Staging; Osteoprotegerin; Prognosis; Prostate-Specific Antigen; Prostatic Neoplasms; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Tumor Cells, Cultured; Up-Regulation

Prostate cancers (PCas) produce factors that can serve as biomarkers for tumor metastasis and bone progression. Transduced GFP expression by cancer cells can be imaged to monitor therapy. We exploited both concepts by developing a GFP-expressing PCa cell line that expresses PTHrP and studying it in an animal model of malignancy with methods that assess the skeletal progression of this tumor.. We developed a GFP-producing PCa cell line by stable transduction of PC-3 PCa cells. This PC-3 variant was used to study tumor progression in an immunocompromised mouse model. Skeletal progression of the PCa cells and the effects of pamidronate administration were evaluated radiologically, fluorometrically, and by measurement of serum tumor markers.. The PC-3 cells produced extensive bone lesions when injected into the tibia of immunocompromised mice. The skeletal progression of the PC-3 cells could be monitored by GFP optical imaging, X-ray, and by measurements of tumor products in serum, notably PTHrP and OPG. Pamidronate treatment reduced tumor burden as assessed at autopsy by imaging and biomarkers.. Pamidronate treatment exhibited anti-tumor effects that were reflected by decreases in serum PTHrP, OPG, and by GFP and radiological imaging procedures. Imaging of GFP expression enables real-time monitoring of tumor growth in the bone. PTHrP and OPG may be useful as tumor biomarkers for PCa that has metastasized to bone. This novel human PCa model can be used to study the clinical potential of diagnostic and therapeutic modalities in the skeletal progression of PCas.

Topics: Adenocarcinoma; Animals; Antineoplastic Agents; Biomarkers, Tumor; Bone Neoplasms; Calcium; Carrier Proteins; Cell Line, Tumor; Diphosphonates; Disease Models, Animal; Glycoproteins; Green Fluorescent Proteins; Humans; Interleukin-6; Interleukin-8; Male; Membrane Glycoproteins; Mice; Mice, SCID; Microscopy, Fluorescence; Osteoprotegerin; Pamidronate; Parathyroid Hormone-Related Protein; Prostatic Neoplasms; Radiography; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Transduction, Genetic

Osteoprotegerin (OPG), a critical regulator of osteoclastogenesis, is expressed by prostate cancer cells, and OPG levels are increased in patients with prostate cancer bone metastases. The objective of this study was to investigate the effects of OPG overexpression on prostate cancer cells and prostate cancer/bone cell interactions in vitro and in vivo. OPG-transfected C4-2 cells expressed 8.0 ng OPG per mL per 10(6) cells, whereas no OPG was detected in the media of C4-2 cells transfected with a control plasmid. OPG overexpressed by C4-2 cells protected these cells from tumor necrosis factor-related apoptosis-inducing ligand-induced apoptosis and decreased osteoclast formation. Subcutaneous OPG-C4-2 and pcDNA-C4-2 tumors exhibited similar growth and take-rate characteristics. However, when grown in bone, tumor volume was decreased in OPG-C4-2 versus pcDNA-C4-2 (P=0.0017). OPG expressed by C4-2 cells caused increases in bone mineral density (P=0.0074) and percentage of trabecular bone volume (P=0.007), and decreases in numbers of osteoblasts and osteoclasts when compared with intratibial pcDNA-C4-2 tumors (P=0.003 and P=0.019, respectively). In summary, our data show that increased expression of OPG in C4-2 cells does not directly affect proliferation of prostate cancer cells but indirectly decreases growth of C4-2 tumors in the bone environment. Our data also show that OPG expressed by C4-2 cells inhibits bone lysis associated with C4-2 bone metastasis, which results in net increases in bone volume. We therefore hypothesize that OPG expressed in prostate cancer patient bone metastases may be at least partially responsible for the osteoblastic character of most prostate cancer bone lesions.

Topics: Animals; Apoptosis; Apoptosis Regulatory Proteins; Bone Neoplasms; Culture Media, Conditioned; Glycoproteins; Humans; Male; Membrane Glycoproteins; Mice; Mice, SCID; Osteoblasts; Osteoclasts; Osteolysis; Osteoprotegerin; Prostatic Neoplasms; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; RNA, Messenger; Survival Rate; TNF-Related Apoptosis-Inducing Ligand; Tumor Cells, Cultured; Tumor Necrosis Factor-alpha; Up-Regulation

The present study was undertaken to test the effects of prostate cancer cell lines (LNCaP, DU145, PC3, and MDA PCa 2b) on osteoclastogenesis. Crude conditioned medium (CM) from all four prostate cancer cell lines enhanced expression of the mRNA for receptor activator of NF-kappaB ligand (RANKL) in a mouse osteoblast cell line, MC3T3-E1; however, CM had no effect on expression of osteoprotegerin (OPG) mRNA. Coculture of MC3T3-E1 with prostate cancer cells yielded similar results. The number of mature osteoclasts induced by soluble RANKL increased significantly when osteoclast precursor cells were cultured with CM from LNCaP and DU145 cells. CM from LNCaP and DU145 cells also induced maturation from precursor in the absence of soluble RANKL, and this effect was not blocked by OPG. Addition of CM from DU145 cells increased expression of MMP-9 mRNA by osteoclast precursors. Our findings indicate that prostate cancer mediates osteoclastogenesis through induction of RANKL expression by osteoblasts and through direct actions on osteoclast precursors mediated by some factors other than RANKL.

Topics: Bone Neoplasms; Carrier Proteins; Cathepsin K; Cathepsins; Cell Line, Tumor; Cytokines; Glycoproteins; Humans; Male; Matrix Metalloproteinase 9; Membrane Glycoproteins; Osteoclasts; Osteoprotegerin; Prostatic Neoplasms; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; RNA, Messenger; Stem Cells

We developed a rodent model that mimics the osteoblastic and osteolytic changes associated with human metastatic prostate cancer. Microarray analysis identified MMP-7, cathepsin-K, and apolipoprotein D as being upregulated at the tumor-bone interface. MMP-7, which was produced by osteoclasts at the tumor-bone interface, was capable of processing RANKL to a soluble form that promoted osteoclast activation. MMP-7-deficient mice demonstrated reduced prostate tumor-induced osteolysis and RANKL processing. This study suggests that inhibition of MMP-7 will have therapeutic benefit in the treatment of prostate cancer-induced osteolysis.

Topics: Acid Phosphatase; Actins; Animals; Carrier Proteins; Disease Models, Animal; Down-Regulation; Gene Expression; Gene Expression Profiling; Glycoproteins; Humans; Isoenzymes; Male; Matrix Metalloproteinase 7; Membrane Glycoproteins; Mice; Mice, Inbred C57BL; Mice, Knockout; Models, Biological; Monocytes; Osteoclasts; Osteolysis; Osteoprotegerin; Parathyroid Hormone-Related Protein; Prostatic Neoplasms; RANK Ligand; Rats; Rats, Inbred F344; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Skull; Tartrate-Resistant Acid Phosphatase; Up-Regulation

Zoledronic acid (ZA) has been shown to inhibit prostate tumor growth in vitro and have beneficial effects in patients with advanced prostate cancer (CaP). The aim of this study was to determine whether ZA exhibits direct anti-tumor effects on CaP cells in vivo. To distinguish the effects of inhibition of osteolysis and direct anti-tumor activity of ZA in vivo, we compared the results of treatment with ZA and osteoprotegerin (Fc-OPG), which inhibits osteolysis, but without significant direct anti-tumor effects. In vitro Fc-OPG had no significant effects on C4-2 proliferation, whereas ZA decreased proliferation. However, both agents decreased tumor growth in bone. Moreover, both increased bone volume and prevented the overall decreases in BMD associated with growth of C4-2 cells in bone. Our study provides novel and significant observations that the in vivo effects of ZA are consistent with indirect effects mediated by osteoclasts.

Topics: Animals; Antibodies; Antineoplastic Agents; Apoptosis; Bone Density; Bone Density Conservation Agents; Bone Neoplasms; Cell Proliferation; Densitometry; Diphosphonates; Glycoproteins; Humans; Imidazoles; Immunoglobulin Fc Fragments; In Vitro Techniques; Male; Mice; Mice, SCID; Neoplasm Metastasis; Osteoclasts; Osteolysis; Osteoprotegerin; Prostatic Neoplasms; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Tibia; Time Factors; Zoledronic Acid

Adenocarcinoma of the prostate exhibits a clear propensity for bone and is associated with the formation of osteoblastic metastases. It has previously been suggested that osteoclast activity may be necessary for the development of these osteoblastic metastases based on data from lytic and mixed lytic-blastic tumors. Here we investigate the effects of complete in vivo osteoclast depletion via the blockade of receptor activator of NF:kappaB (RANK) on the establishment and progression of purely osteoblastic (LAPC-9 cells) bone lesions induced by human prostate cancer cells using a SCID mouse intratibial injection model. The subcutaneous administration of the RANK antagonist (15 mg/kg) RANK:Fc did not prevent the formation of purely osteoblastic lesions, indicating that osteoclasts may not be essential to the initial development of osteoblastic metastases. However, RANK:Fc protein appeared to inhibit the progression of established osteoblastic lesions, suggesting that osteoclasts may be involved in the subsequent growth of these tumors once they are already present. In contrast, RANK:Fc treatment effectively blocked the establishment and progression of purely osteolytic lesions formed by PC-3 cells, which served as a positive control. These results indicate that in vivo RANK blockade may not be effective for the prevention of osteoblastic metastasis but may potentially represent a novel therapy that limits the growth of established metastatic CaP lesions in bone.

Topics: Animals; Bone Neoplasms; Glycoproteins; Immunoglobulin Fc Fragments; Male; Mice; Mice, SCID; Osteoblasts; Osteoclasts; Osteolysis; Osteoprotegerin; Prostatic Neoplasms; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Recombinant Fusion Proteins

Prostate cancer is the most commonly diagnosed malignancy in men and is often associated with bone metastases. Prostate cancer bone lesions can be lytic or schlerotic, with the latter predominating. Bone morphogenetic proteins (BMPs) are a family of growth factors, which may play a role in the formation of prostate cancer osteoblastic bone metastases. This study evaluated the effects of BMPs on prostate cancer cell lines. We observed growth inhibitory effects of BMP-2 and -4 on LNCaP, while PC-3 was unaffected. Flow cytometric analysis determined that LNCaP cell growth was arrested in G(1) after bone morphogenetic protein-2 treatment. Treatment of LNCaP and PC-3 with BMP-2 and -4 activated downstream signaling pathways involving SMAD-1, up-regulation of p21(CIP1/WAF1) and changes in retinoblastoma (Rb) phosphorylation. Interestingly, bone morphogenetic protein-2 treatment stimulated a 2.7-fold increase in osteoprotegerin (OPG), a molecule, which inhibits osteoclastogenesis, production in PC-3.

Topics: Bone Morphogenetic Protein 2; Bone Morphogenetic Protein 4; Bone Morphogenetic Proteins; Bone Neoplasms; Cell Division; Cyclin-Dependent Kinase Inhibitor p21; Cyclins; DNA-Binding Proteins; Flow Cytometry; G1 Phase; Glycoproteins; Humans; Male; Osteoprotegerin; Phosphorylation; Prostatic Neoplasms; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Retinoblastoma Protein; Signal Transduction; Smad Proteins; Smad1 Protein; Trans-Activators; Transforming Growth Factor beta; Tumor Cells, Cultured; Up-Regulation

Osteoprotegerin (OPG) is a tumour and/or bone derived factor that may protect tumour cells from apoptosis. In this study, we have measured serum OPG levels in untreated prostate cancer patients with advanced prostate cancer compared to patients with organ confined disease and in treated patients receiving androgen ablation.. Serum OPG levels were measured by ELISA in samples collected from 104 patients with either newly diagnosed (n = 59) or advanced prostate cancer treated by androgen ablation (n = 45) and compared with levels in serum from patients with benign prostatic hyperplasia (BPH) (n = 10) and young healthy men (n = 10).. Untreated patients with locally advanced disease had significantly higher OPG levels than those with organ confined disease. Patients with advanced disease responding to androgen ablation (serum PSA < 1 ng/ml) had serum OPG levels that were significantly lower than those with clinically progressing disease (PSA > 10 ng/ml). OPG levels in the latter were not significantly different from levels in patients with early signs of biochemical progression (PSA >1 but <10 ng/ml).. OPG is a potential new marker, which is elevated in the serum of patients with advanced prostate cancer and may be an indicator of early disease progression.

Topics: Adult; Aged; Aged, 80 and over; Androgen Antagonists; Biomarkers, Tumor; Case-Control Studies; Disease Progression; Enzyme-Linked Immunosorbent Assay; Glycoproteins; Humans; Male; Middle Aged; Osteoprotegerin; Predictive Value of Tests; Prognosis; Prostatic Neoplasms; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Treatment Outcome

Our aim was to assess the diagnostic accuracy of bone markers in serum of patients with prostate cancer (PCa) for early detection of bone metastases and their usefulness as predictors of PCa-caused mortality. In sera of 117 PCa patients (pN0M0, n = 39; pN1M0, n = 34; M1, n = 44), 35 healthy men and 35 patients with benign prostatic hyperplasia, bone formation markers [total and bone-specific alkaline phosphatase (tALP, bALP), amino-terminal procollagen propeptides of type I collagen (P1NP), osteocalcin (OC)], bone resorption markers [bone sialoprotein (BSP), cross-linked C-terminal (CTX) and cross-linked N-terminal (NTX) telopeptides of type I collagen, tartrate-resistant acid phosphatase isoenzyme 5b (TRAP)] and osteoclastogenesis markers [osteoprotegerin (OPG), receptor activator of nuclear factor kappaB ligand (RANKL)] were measured. tALP, bALP, BSP, P1NP, TRAP, NTX and OPG were significantly increased in PCa patients with bone metastases compared to patients without metastases. OPG showed the best discriminatory power to differentiate between these patients. Logistic regression analysis resulted in a model with OPG and TRAP as variables that predicted bone metastasis with an overall correct classification of 93%. Patients with concentrations of OPG, P1NP, tALP, bALP, BSP, NTX, TRAP and CTX above cut-off levels showed significantly shorter survival than patients with low marker concentrations. Multivariate Cox proportional hazards regression revealed that only OPG and BSP were independent prognostic factors for PCa-related death. Thus, the importance of serum OPG in detecting bone metastatic spread, alone or in combination with other bone markers, and predicting survival in PCa patients has been clearly demonstrated.

Topics: Adult; Aged; Biomarkers, Tumor; Bone Neoplasms; Bone Resorption; Carcinoma; Glycoproteins; Humans; Male; Middle Aged; Osteoprotegerin; Prognosis; Prostatic Neoplasms; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Regression Analysis; Retrospective Studies; Survival Analysis

Tumor-derived OPG has recently been shown to protect prostate cancer cells from apoptosis. This study has confirmed that bone marrow stromal cell-derived OPG also suppresses cytokine-induced apoptosis in this tumor type, suggesting that it may be the presence of bone-derived OPG that is responsible for the observed preference of these cells in colonizing the skeleton.. Metastasis to the skeleton occurs in around 70% of patients with advanced prostate cancer (CaP), suggesting that the bone microenvironment may provide factors that favor the growth and survival of prostate cancer cells. Osteoprotegerin (OPG) is a molecule involved in bone remodeling, where it acts as an inhibitor of osteoclastogenesis, but it is also a decoy receptor for TRAIL/Apo 2L, a member of the TNF family of pro-apoptotic cytokines. The aim of this study was to determine whether OPG produced by human bone marrow stromal cells could protect prostate cancer cells from TRAIL-induced apoptosis.. Human bone marrow stromal cell cultures were generated from bone biopsies taken from newly diagnosed untreated CaP patients with (M1) or without (M0) bony metastasis. The stromal origin of these cells was confirmed by Western blot analysis using antibodies raised to stromal and epithelial markers. Media were conditioned over the cultures of these cells for 4 days, and levels of OPG were determined using an ELISA. The human prostate cancer cell line PC3 was challenged with TRAIL (50 ng/ml) in fresh media or in media supplemented with 50% conditioned media, and apoptosis was assessed using DAPI stain. The effects of specific removal of OPG activity by immunoprecipitation or by co-treatment of cultures with an alternative ligand for OPG (RANKL) were also tested.. The presence of stromal cell conditioned media in PC3 culture significantly reduced TRAIL-induced apoptosis. All stromal cell lines isolated were shown to express OPG and to release this protein into the conditioned media. Immunoprecipitation of OPG and co-treatment of cultures with sRANKL reversed the protective effects of the conditioned media. These data suggest that at least part of the survival advantage gained by CaP cells in colonizing bone may be caused by the production of OPG by tumor-associated stromal cells.

Topics: Apoptosis; Apoptosis Regulatory Proteins; Bone Marrow Cells; Bone Neoplasms; Carrier Proteins; Cells, Cultured; Glycoproteins; Humans; Immunohistochemistry; Male; Membrane Glycoproteins; Osteoprotegerin; Prostatic Neoplasms; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Stromal Cells; TNF-Related Apoptosis-Inducing Ligand; Tumor Necrosis Factor-alpha

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.

Topics: Animals; Bone Density; Bone Neoplasms; Glycoproteins; Injections, Subcutaneous; Lymphatic Metastasis; Male; Mice; Mice, Nude; Mice, SCID; Osteoblasts; Osteoprotegerin; Prostate-Specific Antigen; Prostatic Neoplasms; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Tibia; Tumor Cells, Cultured; Xenograft Model Antitumor Assays

Prostate adenocarcinoma is associated with the formation of osteoblastic metastases in bone. It is hypothesized that osteoclastogenesis is a critical component in the development of skeletal metastases. These findings, however, were generally noted in predominantly osteolytic lesions. The pathophysiology of osteoblastic lesions remains unknown but the type of bone lesion formed may be influenced by the cytokines produced by prostate tumors. To test this theory, we implanted PC-3 and LAPC-9 cells into the tibias of SCID mice. These mice were sacrificed at 1, 2, 4, 6, and 8 weeks after implantation and histologic analysis was performed on these tibias. PCR analysis was also performed on bulk tumors. The results showed that the PC-3 implanted tibias developed pure osteolytic lesions while the LAPC-9 implanted tibias developed pure osteoblastic lesions on radiographs. Analysis of tibias after injection with PC-3 cells revealed progressive osteolytic lesions with abundant osteoclast activity at 2 weeks and destruction of the proximal tibia at 6 weeks after cell implantation. In contrast, the LAPC-9 cells formed osteoblastic lesions six weeks after cell injection. There were rare osteoclasts prior to the establishment of the osteoblastic lesions but greater osteoclast activity was noted with remodeling of the osteoblastic lesion 8 weeks after implantation of the tumor cells. PCR analysis revealed that PC-3 cells produced RANKL, IL-1, and TNF-alpha, which are associated with osteoclastogenesis. In contrast, LAPC-9 cells produced osteoprotegerin, which blocks osteoclast production and no detectable levels of RANKL or IL-1 and only minimal amounts of TNF-alpha were noted. These cells secreted BMP-2, -4, -6, and IL-6, which are associated with bone formation. These results suggest that the role of the osteoclast in the development of a metastatic lesion is variable depending on the phenotype of the prostate cancer cells, and that tumor-induced osteolysis may not be required for osteoblastic metastases.

Topics: Animals; Cytokines; Gene Expression; Glycoproteins; Humans; Immunohistochemistry; Male; Mice; Mice, SCID; Neoplasm Transplantation; Osteoblasts; Osteolysis; Osteoprotegerin; Phenotype; Polymerase Chain Reaction; Prostatic Neoplasms; Radiography; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Tibia; Tumor Cells, Cultured

Human prostate cancer frequently metastasizes to bone, where it gives rise to osteoblastic bone metastases with an underlying osteoclastic component and subsequent bone pain. However, the importance of osteoclastogenesis in the development of prostate cancer bone lesions in humans is unclear. Osteoprotegerin/osteoclastogenesis inhibitory factor (OCIF) is a member of the tumor necrosis factor receptor family and a novel secreted protein, and it is a negative regulator of osteoclast differentiation, activation, and survival both in vitro and in vivo. In the present study we used a model in which human LNCaP prostate cancer cells that give rise to osteoblastic bone tumors were injected directly into the intramedullary space of human adult bone implanted into nonobese diabetic/severe combined immunodeficient mice to investigate whether the new bone-resorption inhibitor osteoprotegerin/OCIF would inhibit the development of new bone tumors and the progression of established osteoblastic bone tumors. The mice were given consecutive daily s.c. injections of recombinant human OCIF (rhOCIF; 100 micro g/mouse/day) for 2 weeks starting either immediately or 2 weeks after injection of the LNCaP cells. In both protocols, rhOCIF markedly inhibited both the development of bone tumors and the progression of established bone tumor foci quantified by histological examination. Histomorphometrical analysis revealed that rhOCIF markedly reduced the number of osteoclasts and the size of the tumors at the bone sites, but that it had no effect on the local growth of s.c. LNCaP tumors or on LNCaP cell proliferation in culture. These findings demonstrate that osteoclasts play an important role in bone tumor by prostate cancer, and that rhOCIF decreases the LNCaP prostate cancer burden selectively in bone, suppresses the progression of established tumor lesions, and prevents the development of new lesions. These results suggest that inhibition of osteoclastic bone resorption may be an effective therapy for the treatment of prostate cancer that has colonized bone.

Topics: Animals; Bone Neoplasms; Cell Division; Glycoproteins; Humans; Male; Mice; Mice, Inbred NOD; Mice, SCID; Osteoprotegerin; Prostatic Neoplasms; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Recombinant Proteins; Tumor Cells, Cultured; Xenograft Model Antitumor Assays

Prostate cancer specifically metastasizes to bone where it leads to bone formation. We previously reported that coculturing MDA PCa 2b prostate cancer cells with primary mouse osteoblasts (PMOs) induced PMO proliferation and differentiation. An osteoblastic reaction was also observed in vivo after injection of MDA PCa 2b cells into the bones of severe combined immunodeficient disease mice. The aim of this study was to identify the sequence of events that leads to these osteoblastic lesions in vivo and, using this in vitro model, to define the contributions of various genes and cellular pathways in the pathophysiology of osteoblastic bone metastases of prostate cancer.. We show histological evidence of de novo bone formation as early as 2 weeks after injection of MDA PCa 2b cells in the bone of severe combined immunodeficient disease mice. In vitro, we show that PMOs induce MDA PCa 2b proliferation, suggesting a synergistic paracrine loop between these cells and PMOs. Endothelin (ET)-1, which is a mitogen for several cell types, is produced by all prostate cancer cell lines tested, and Atrasentan, an antagonist of ET-1 receptor A, partially reversed PMO proliferation induced by MDA PCa 2b cells. ET-1 is known to be comitogenic with a number of growth factors, including insulin-like growth factor (IGF)-I. In this study, we report that IGF-binding protein (IGFBP)-3 transcripts (that regulate levels of free IGF) are down-regulated in prostate cancer cells cocultured with PMO, whereas prostate-specific antigen (a protease known to cleave IGFBP-3) is detected in the 150-400 ng/ml range. Accordingly, IGFBP-3 has antiproliferative effects in PMOs, which were attenuated in our in vitro system. Taken together, our studies also implicate the IGF axis to play a role in this model of bone metastases. Secondly, the transcript level of mouse double minute 2 (a protein that regulate p53) was increased in prostate cancer cells grown with PMOs. The p53-dependent and -independent oncogenic activities of mouse double minute 2 suggest that osteoblasts induce a survival advantage in prostate cancer cells. Lastly, we show that expression of osteoprotegerin is decreased and of receptor activator of nuclear factor-kappaB ligand is increased in PMOs cultured in the presence of MDA PCa 2b cells, two events associated with osteoclast activation and bone resorption.. Our results provide evidence that multiple and distinct molecular events affecting both bone formation and bone resorption concur to the increase bone mass in prostate cancer bone metastases. These data also provide a rationale for developing therapeutic strategies designed to target these molecular changes.

Topics: Alkaline Phosphatase; Animals; Blotting, Northern; Carrier Proteins; Cell Differentiation; Cell Division; Cell Line, Tumor; Cell Survival; Coculture Techniques; Culture Media, Conditioned; DNA; DNA, Complementary; Down-Regulation; Glycoproteins; Humans; Insulin-Like Growth Factor Binding Protein 3; Insulin-Like Growth Factor I; Male; Membrane Glycoproteins; Mice; Mice, SCID; Models, Biological; Neoplasm Metastasis; Oligonucleotide Array Sequence Analysis; Osteoblasts; Osteoprotegerin; Phenotype; Prostatic Neoplasms; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; RNA; RNA, Messenger

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.

Topics: Animals; Bone Neoplasms; Carrier Proteins; Disease Progression; Glycoproteins; Immunoglobulin Fc Fragments; Immunoglobulin G; Male; Membrane Glycoproteins; Mice; Mice, SCID; Osteogenesis; Osteoprotegerin; Prostatic Neoplasms; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Recombinant Fusion Proteins

We evaluated the behavior and diagnostic usefulness of the osteoclastogenesis proteins osteoprotegerin and receptor activator of nuclear factor-kappaB ligand (RANKL) in the serum of patients with prostate cancer (PCa).. Serum osteoprotegerin and RANKL were retrospectively measured in 117 patients with prostate cancer, including 39 with stage pN0M0, 34 with stage pN1M0 and 44 with bone metastases, in 35 presumably healthy men and in 35 patients with benign prostatic hyperplasia (BPH). The association of these components with clinical data (tumor stage and grade) and receiver operating characteristics curves compared with the bone formation marker alkaline phosphatase and bone resorption marker crosslaps (cross-linked C-terminal telopeptides of type I collagen) were calculated.. Osteoprotegerin was increased in patients with bone metastases, while those with localized cancer or lymph node metastases had values similar to those in presumably healthy controls and patients with BPH. RANKL did not differ among the control, BPH and PCa subgroups. Thus, the ratio of osteoprotegerin-to-RANKL showed behavior similar to that of osteoprotegerin. Osteoprotegerin and RANKL did not show any significant correlation with tumor stage, histological tumor grade, total prostate specific antigen, alkaline phosphatase activity or crosslaps. ROC analysis data proved that osteoprotegerin had a better diagnostic accuracy than alkaline phosphatase or crosslaps for detecting bone metastases in PCa cases.. Serum osteoprotegerin but not RANKL indicates disturbed osteoclastogenesis in patients with PCa and bone metastatic spread. It could be used as a marker for bone metastases.

Topics: Adult; Aged; Alkaline Phosphatase; Biomarkers, Tumor; Bone Neoplasms; Carcinoma; Carrier Proteins; Collagen; Collagen Type I; Glycoproteins; Humans; Lymphatic Metastasis; Male; Membrane Glycoproteins; Middle Aged; Osteogenesis; Osteoprotegerin; Peptides; Prostatic Hyperplasia; Prostatic Neoplasms; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Retrospective Studies; ROC Curve; Sensitivity and Specificity

Factors that aid survival of prostate cancer cells in the presence of the various categories of cytotoxic cytokines present in tumors in vivo are largely unknown. Osteoprotegerin (OPG) is a decoy receptor for tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) that inhibits TRAIL-induced apoptosis. In relation to this activity, we hypothesized that the ability to produce OPG by prostate cancer cells would confer a survival advantage on these cells. In this study we have demonstrated that high levels of OPG are produced by the hormone-insensitive prostate cancer cell lines PC3 and Du145, whereas the hormone-sensitive cell line LNCaP produced 10-20-fold less OPG under the same conditions. A strong negative correlation was observed between levels of endogenously produced OPG in the medium and the capacity of TRAIL to induce apoptosis in cells that produced high levels of OPG. The antiapoptotic effect of OPG was reversed by coadministration of 100-fold molar excess of receptor-activator of nuclear factor-kappaB ligand, another protein that selectively binds OPG. These observations suggest that prostate cancer-derived OPG may be an important survival factor in hormone-resistant prostate cancer cells.

Topics: Antibodies; Apoptosis; Apoptosis Regulatory Proteins; Cell Survival; Drug Interactions; Glycoproteins; Humans; Male; Membrane Glycoproteins; Osteoprotegerin; Prostatic Neoplasms; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Recombinant Proteins; TNF-Related Apoptosis-Inducing Ligand; Tumor Cells, Cultured; Tumor Necrosis Factor-alpha

To improve the therapy of advanced prostate cancer (CaP), it is critical to develop animal models that mimic CaP bone metastases. Unlike the human disease, CaP xenograft models rarely metastasize spontaneously to bone from the orthotopic site of primary tumor growth.. Single-cell suspensions of LNCaP, PC-3, LuCaP 35, and LuCaP 23.1 CaP cells were injected directly into tibia of SCID mice. Immunohistochemistry and bone histomorphometrical analyses were performed to characterize these osseous-CaP models.. LuCaP 23.1 yields an osteoblastic response, LNCaP yields mixed lesions, and LuCaP 35 and PC-3 result in osteolytic responses. We have detected osteoprotegerin, RANK ligand, parathyroid hormone-related protein, and endothelin-1, proteins associated with bone growth and remodeling, in the CaP cells grown in the bone.. These animal models can be used to study biological interactions, pathways, and potential therapeutic targets, and also to evaluate new agents for treatment and prevention of CaP bone metastasis.

Topics: Animals; Bone Density; Bone Neoplasms; Bone Remodeling; Carrier Proteins; Disease Models, Animal; Endothelin-1; Glycoproteins; Humans; Immunohistochemistry; Kinetics; Male; Membrane Glycoproteins; Neoplasm Transplantation; Orchiectomy; Osteoblasts; Osteoclasts; Osteoprotegerin; Parathyroid Hormone-Related Protein; Prostatic Neoplasms; Proteins; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Tibia; Transplantation, Heterologous; Tumor Cells, Cultured

Osteoprotegerin (OPG), a member of the tumor necrosis receptor family, is produced by various tissues and inhibits osteoclast differentiation and activity. Since the metastasis of prostate cancer to bone often induces osteosclerosis, the possibility that these tumor cells secrete OPG is of interest. We have investigated whether the prostate cancer cell lines LNCaP, PC-3, and DU-145 produce and secrete OPG in vitro and if the production might be regulated by cytokines involved in remodeling of bone. OPG transcripts were detected by RT-PCR in all cell lines. OPG in culture media was analyzed by ELISA. In all three lineages, treatment with tumor necrosis factor-alpha and interleukin-1 beta dose dependently (5-5000 pM) stimulated the OPG secretion. Treatment with tumor necrosis factor-beta in increasing concentrations (1-1000 pM) stimulated OPG secretion in PC-3 but had no effect on the DU-145 and LNCaP cells. Dexamethasone (100 pM) had a small, but not significant, inhibitory effect on OPG secretion from DU-145 and LNCaP. In human non-malignant prostate cells, used as controls, there was no effect of IL-1 or TNFs on the secretion rate of OPG.

Topics: Cytokines; Dexamethasone; Glycoproteins; Humans; Interleukin-1; Lymphotoxin-alpha; Male; Osteoprotegerin; Prostatic Neoplasms; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Tumor Cells, Cultured; Tumor Necrosis Factor-alpha

To investigate the expression of osteoprotegerin (OPG) and RANK ligand (RANKL) in human prostatic tissues. The factors regulating the increased turnover associated with prostate cancer (CaP) bone metastasis are unknown. OPG and RANKL are recently identified regulators of bone resorption and bone remodeling.. Tissues from 28 patients with CaP and from 4 normal organ donors were analyzed by reverse transcriptase-polymerase chain reaction and immunohistochemistry for the expression of OPG and RANKL.. OPG and RANKL messages were detected in both normal and cancerous prostate samples. In the normal prostate, OPG protein was detected in luminal epithelial and stromal cells (5% to 65% and 15% to 70%, respectively) and RANKL immunoreactivity was observed in 15% to 50% of basal epithelial cells, 40% to 90% of luminal epithelial cells, and 70% to 100% of stromal cells. OPG was not detected in 8 of 10 primary CaP specimens; RANKL was heterogeneously expressed in 10 of 11 CaP specimens. The percentage of tumor cells expressing OPG and RANKL was significantly increased in all CaP bone metastases compared with nonosseous metastases or primary CaP.. CaP bone metastases were consistently immunoreactive for both OPG and RANKL compared with nonosseous metastases or primary CaP. The presence of these crucial bone resorption regulators in CaP bone metastases suggests a mechanism whereby CaP cells may modulate bone turnover and has profound implications for the establishment and development of CaP bone metastases in advanced disease.

Topics: Aged; Aged, 80 and over; Base Sequence; Bone Neoplasms; Carrier Proteins; Cytokines; Glycoproteins; Humans; Immunohistochemistry; Lymphatic Metastasis; Male; Membrane Glycoproteins; Middle Aged; Osteoprotegerin; Prostate; Prostatic Neoplasms; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; RNA, Messenger

Prostate cancer frequently metastasizes to bone. However, unlike many other tumors that produce osteolytic lesions, prostate cancer produces osteoblastic lesions through unknown mechanisms. In the current study, we explored the ability and mechanism of an osteotropic prostate cancer cell line (C4-2B) to induce mineralization.. C4-2B cells were grown in promineralization media. Mineral deposition was characterized using von Kossa staining, calcium retention, alizarin red staining, Raman spectroscopy, and electron microscopy. Expression of osteoblast-related proteins was determined by RT-PCR. The nuclear level of the bone-specific transcription factor Cbfa1 was determined using western analysis and the effect of inhibiting Cbfa1 function, using a "decoy" Cbfa1 response element oligo, on mineralization was determined.. The studies demonstrated that C4-2B cells, but not its nonosteotropic parent cell line LNCaP, has an osteoblastlike phenotype including production of alkaline phosphatase, osteocalcin, osteonectin, bone sialoprotein, osteoprotegerin (OPG), and OPG ligand. Most importantly, the C4-2B cells produced hydroxyapatite mineral in vitro. Furthermore, C4-2B cells expressed high nuclear levels of the bone-specific transcription factor Cbfa1, compared to LNCaP cells, which accounts for their ability to produce bone-specific proteins. Inhibition of Cbfa1, using decoy DNA Cbfa1 response elements, abrogated the ability of C4-2B to produce mineral. Finally, we determined that C4-2B cells express bone morphogenic protein-7, a known inducer of Cbfa1 expression.. These data demonstrate a novel mechanism through which prostate cancer cells may directly contribute to the osteoblastic component that characterize their skeletal metastatic lesions. Prostate 47:212-221, 2001.

Topics: Anthraquinones; Bone Morphogenetic Protein 7; Bone Morphogenetic Proteins; Bone Neoplasms; Calcinosis; Calcium; Cell Division; Core Binding Factor Alpha 1 Subunit; Durapatite; Gene Expression Regulation, Neoplastic; Glycoproteins; Humans; Male; Neoplasm Proteins; Osteoblasts; Osteoprotegerin; Prostatic Neoplasms; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Spectrophotometry, Infrared; Spectrum Analysis, Raman; Staining and Labeling; Transcription Factors; Transforming Growth Factor beta; Tumor Cells, Cultured

Topics: Bone Neoplasms; Carrier Proteins; Glycoproteins; Humans; Male; Membrane Glycoproteins; Osteoclasts; Osteolysis; Osteoprotegerin; Prostatic Neoplasms; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor

Prostate cancer (CaP) forms osteoblastic skeletal metastases with an underlying osteoclastic component. However, the importance of osteoclastogenesis in the development of CaP skeletal lesions is unknown. In the present study, we demonstrate that CaP cells directly induce osteoclastogenesis from osteoclast precursors in the absence of underlying stroma in vitro. CaP cells produced a soluble form of receptor activator of NF-kappaB ligand (RANKL), which accounted for the CaP-mediated osteoclastogenesis. To evaluate for the importance of osteoclastogenesis on CaP tumor development in vivo, CaP cells were injected both intratibially and subcutaneously in the same mice, followed by administration of the decoy receptor for RANKL, osteoprotegerin (OPG). OPG completely prevented the establishment of mixed osteolytic/osteoblastic tibial tumors, as were observed in vehicle-treated animals, but it had no effect on subcutaneous tumor growth. Consistent with the role of osteoclasts in tumor development, osteoclast numbers were elevated at the bone/tumor interface in the vehicle-treated mice compared with the normal values in the OPG-treated mice. Furthermore, OPG had no effect on CaP cell viability, proliferation, or basal apoptotic rate in vitro. These results emphasize the important role that osteoclast activity plays in the establishment of CaP skeletal metastases, including those with an osteoblastic component.

Topics: Animals; Bone Neoplasms; Bone Resorption; Carrier Proteins; Glycoproteins; Humans; Male; Membrane Glycoproteins; Mice; Mice, Inbred C57BL; Mice, SCID; Neoplasm Metastasis; Osteoprotegerin; Prostatic Neoplasms; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor; Tibia

Osteoprotegerin (OPG) is a soluble osteoclastogenesis inhibitor that regulates bone turnover. We reported recently that OPG protein expression is significantly increased in prostate cancer (CaP) cells present in bone metastases. The aim of this study was to determine serum OPG levels in patients at different stages of CaP and correlate the results with disease status.. OPG levels were examined in patients with benign prostatic hyperplasia, clinically localized CaP, early recurrence of CaP, and advanced CaP and evidence of bone metastases. Serum OPG levels were measured by sandwich ELISA assays. The serum Crosslaps (sCTX) assay was used to quantify bone resorption in the advanced CaP group.. Serum OPG levels were increased significantly in the advanced CaP group versus all other groups. There was no significant correlation between serum OPG levels and PSA levels either in the advanced CaP group or within any of three treatment subclasses of this group: no Tx, those not treated; Tx, those treated; and R, those treated with resorption blockers. Levels of OPG were negatively correlated with sCTX levels only in the advanced CaP Tx group. sCTX levels correlated with prostate-specific antigen levels in the advanced CaP Tx and R groups but not in the no-Tx group.. Our data show that serum OPG levels are increased with advanced CaP. We hypothesize that OPG levels are related to CaP progression and suggest that further studies of the biological effects of OPG on CaP metastases are warranted.

Topics: Adult; Aged; Aged, 80 and over; Bone Neoplasms; Collagen; Enzyme-Linked Immunosorbent Assay; Glycoproteins; Humans; Male; Middle Aged; Neoplasm Recurrence, Local; Osteoprotegerin; Peptide Fragments; Prostatic Hyperplasia; Prostatic Neoplasms; Receptors, Cytoplasmic and Nuclear; Receptors, Tumor Necrosis Factor