endothelin-1 and Prostatic-Neoplasms

It has been long recognized that skeleton represents one of the most favored metastatic sites for common cancers like breast and prostate. During the last decade the molecular mechanisms that are responsible for the development of bone metastasis have been gradually illuminated. It appears that the bone microenvironment has a pivotal role in this process. Metastatic tumor cells interact with bone triggering a cascade of molecular events that produce osteolytic and/or osteoblastic phenomena. In this review, we summarize and discuss the most significant factors and signaling pathways implicated in bone colonization. Moreover, based on the recent literature and data, we foresee the need for designing novel agents that will efficiently disrupt these interactions among cancer cells and bone microenvironment, bringing hope for more effective treatments.

Topics: Animals; beta Catenin; Biphenyl Compounds; Bone Neoplasms; Bone Remodeling; Breast Neoplasms; Cathepsin K; Chemokine CXCL12; Diphosphonates; Endothelin-1; Female; Humans; Hypoxia; Male; Neoplastic Stem Cells; Osteoblasts; Osteoclasts; Osteolysis; Parathyroid Hormone-Related Protein; Prostatic Neoplasms; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors, CXCR4; Signal Transduction; Urokinase-Type Plasminogen Activator; Wnt Proteins

Recent advances in tumor biology have made remarkable achievements in the development of therapy for metastatic castrate-resistant prostate cancer. These advances reflect a growing appreciation for the role of the tumor microenvironment in promoting prostate cancer progression. Prostate cancer is no longer viewed predominantly as a disease of abnormally proliferating epithelial cells but rather as a disease of complex interactions between prostate cancer epithelial cells (epithelial compartment) and the surrounding tissues (stromal compartment) in which they reside. For example, prostate cancers frequently metastasize to bone, an organ that contains a microenvironment rich in extracellular matrix proteins and stromal cells including hematopoietic cells, osteoblasts, osteoclasts fibroblasts, endothelial cells, adipocytes, immune cells, and mesenchymal stem cells. Multiple signaling pathways provide crosstalk between the epithelial and the stromal compartments to enhance tumor growth, including androgen receptor signaling, tyrosine kinase receptor signaling, and immune surveillance. The rationale to disrupt this "two-compartment" crosstalk has led to the development of drugs that target tumor stromal elements in addition to the cancer epithelial cell.

Topics: Androstenes; Androstenols; Angiogenesis Inhibitors; Anilides; Animals; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antineoplastic Agents; Antineoplastic Agents, Hormonal; Atrasentan; Benzamides; Bevacizumab; Biomarkers, Tumor; Bone Remodeling; Cancer Vaccines; Clinical Trials as Topic; Clusterin; Dasatinib; Denosumab; Endothelin-1; Humans; Immunotherapy; Indoles; Ipilimumab; Male; Mice; Mice, SCID; Molecular Targeted Therapy; Nitriles; Orchiectomy; Phenylthiohydantoin; Prostate-Specific Antigen; Prostatic Neoplasms; Pyridines; Pyrimidines; Pyrroles; Pyrrolidines; RANK Ligand; Receptor Cross-Talk; Receptors, Androgen; Signal Transduction; Sunitinib; Taxoids; Thiazoles; Tissue Extracts; Treatment Failure; Tumor Microenvironment; Xenograft Model Antitumor Assays

Patients with prostate cancer who have progression of their disease while on androgen deprivation therapy have limited therapeutic options. Docetaxel is currently the only agent that increases overall survival in patients with metastatic, castration-resistant prostate cancer; additional agents are needed.. This review will describe the importance of endothelin-1 (ET-1) for growth of prostate cancer cells, development of bone metastases, and pain responses; the preclinical data for zibotentan, a specific inhibitor of the ET(A) receptor; and the clinical development of atrasentan, a first-generation ET receptor inhibitor, and zibotentan, a more selective inhibitor of the ET(A) receptor.. Readers will understand the importance of ET-1 as a novel pathway to target for patients with castration-resistant prostate cancer due to its association with prostate cancer growth, metastases to bone, and pain. Readers will learn about the preclinical and clinical development of zibotentan, including the promising Phase II results that have resulted in an extensive Phase III clinical trials program.. Modulating the activity of ET-1 through the ET(A) receptor is a novel target for treating patients with metastatic, castration-resistant prostate cancer. There are currently three ongoing Phase III trials with zibotentan, a selective ET(A) inhibitor, to determine the effect of this agent on overall survival in these patients.

Topics: Animals; Antineoplastic Agents; Bone Neoplasms; Clinical Trials as Topic; Disease-Free Survival; Drug Evaluation, Preclinical; Endothelin A Receptor Antagonists; Endothelin-1; Humans; Male; Molecular Structure; Neoplasms, Hormone-Dependent; Orchiectomy; Prostatic Neoplasms; Pyrrolidines

Bone metastases are complications of multiple myeloma and solid tumors, including breast and prostate carcinomas. Several reports have demonstrated that the preference to metastasize to bone by tumor cells is not a casual but an addressed event, which relies on specific interactions among tumor cells, bone marrow microenvironment and bone cells. One of the features that gives tumor cells more chances to survive and proliferate into the bone tissue is osteomimicry, that is the ability to acquire a bone cell phenotype, especially osteoblast-like. As clearly demonstrated, prostate and breast cancer cells try to resemble osteoblasts by expressing bone matrix proteins, the specific marker alkaline phosphatase, and molecules regulating the osteoblast/osteoclast cross-talk. Based on this evidence it is crucial to dissect in more detail the molecular mechanisms underlying the osteomimetic properties of cancer cells and identify new therapeutic targets eventually leading to a better and prolonged life expectation for patients with bone.

Topics: Alkaline Phosphatase; beta 2-Microglobulin; Bone Matrix; Bone Morphogenetic Proteins; Bone Neoplasms; Breast Neoplasms; Core Binding Factor Alpha 1 Subunit; Endothelin-1; Female; Humans; Male; Models, Biological; Osteoblasts; Osteolysis; Phenotype; Prostatic Neoplasms; Signal Transduction; Urokinase-Type Plasminogen Activator; Wnt Proteins

Endotelina (ET-1) is the polypeptide about wide spectrum of physiological effects, involved in pathophysiology of cardiovascular and neoplastic diseases. Thus, ET-1 blocking becomes modern therapeutic target. The endothelin receptor antagonists (ERA)--sentans are the intensely studied agents, already approved for an alternative pulmonary hypertension therapy and hormone-resistant prostate cancer treatment. The promising results of conducted clinical trials suggest the possible extension of ERA application in other clinical entities in the close future. The article shortly describes present studied endothelin receptor antagonists and rationale for their introduction to the general clinical practice.

Topics: Animals; Cardiovascular Diseases; Endothelin Receptor Antagonists; Endothelin-1; Humans; Hypertension, Pulmonary; Male; Prostatic Neoplasms

Castration-resistant prostate cancer (CRPC) refers to patients who no longer respond to surgical or medical castration. Standard treatment options are limited.. To review the concepts and rationale behind targeted agents currently in late-stage clinical testing for patients with CRPC.. Novel targeted therapies in clinical trials were identified from registries. The MEDLINE database was searched for all relevant reports published from 1996 to October 2009. Bibliographies of the retrieved articles and major international meeting abstracts were hand-searched to identify additional studies.. Advances in our understanding of the molecular mechanisms underlying prostate cancer (PCa) progression has translated into a variety of treatment approaches. Agents targeting androgen receptor (AR) activation and local steroidogenesis, angiogenesis, immunotherapy, apoptosis, chaperone proteins, the insulin-like growth factor (IGF) pathway, RANK-ligand, endothelin receptors, and the Src family kinases are entering or have recently completed accrual to phase 3 trials for patients with CRPC.. A number of new agents targeting mechanisms of PCa progression with early promising results are in clinical trials and have the potential to provide novel treatment options for CRPC in the near future.

Topics: Androgen Antagonists; Androgen Receptor Antagonists; Endothelin-1; Humans; Immunotherapy; Male; Molecular Chaperones; Orchiectomy; Prostatic Neoplasms; Receptors, Androgen; Receptors, Vascular Endothelial Growth Factor; Treatment Failure; Vascular Endothelial Growth Factor A

The endothelin system comprises the three peptide hormones endothelin (ET)-1, -2, -3, their G protein-coupled receptors, endothelin-A-receptor (ET(A)R) and endothelin-B-receptor (ET(B)R), and the enzymes of endothelin biosynthesis and degradation. In the past two decades, an impressive amount of data has been accumulated investigating the role of the endothelin system in a variety of malignancies. In many cancers, ET-1/ET(A)R interaction induces proliferation, angiogenesis, antiapoptosis and resistance to chemotherapy. Data indicate a pivotal role of the endothelin system in tumorigenesis, local progression and metastasis. Subsequently, novel drugs have been designed inhibiting ET-1 biosynthesis or ET(A)R interaction. A wide range of preclinical data is available on the role of ET(A)R antagonists in gynecological, urological and breast cancers providing evidence for their antiangiogenic, proapoptotic and growth inhibitory effects. Of particular interest is the anti-invasive and antimetastatic efficacy of ET(A)R antagonists and synergism when co-administered with established cancer therapies. Data indicate a future role of ET(A)R antagonists in oncologic therapies.

Topics: Animals; Antineoplastic Agents; Aspartic Acid Endopeptidases; Breast Neoplasms; Endometrial Neoplasms; Endothelin Receptor Antagonists; Endothelin-1; Endothelin-Converting Enzymes; Female; Humans; Kidney Neoplasms; Male; Metalloendopeptidases; Ovarian Neoplasms; Prostatic Neoplasms; Receptors, Endothelin; Urinary Bladder Neoplasms; Urogenital Neoplasms; Uterine Cervical Neoplasms

Although the number of men presenting with metastatic prostate cancer has decreased significantly over the last several years, the death rate for those men is essentially unchanged. Effective treatments have not existed for prostate cancer progressing after androgen deprivation therapy until recently. Docetaxel based chemotherapy has demonstrated to extend patient survival in two large randomized studies. These studies have provided the impetus to combine docetaxel with novel biologic drugs to further consolidate the gains in long-term outcome. With the arrival of new therapies such as epothilone analogues, small molecule receptor tyrosine kinase inhibitors, monoclonal antibodies, bone-targeted drugs, antisense oligonucleotides, antiangiogenics drugs and endothelin receptor antagonists, the future of prostate cancer therapy appears promising.

Topics: Angiogenesis Inhibitors; Antibodies, Monoclonal; Antineoplastic Agents; Boronic Acids; Bortezomib; Calcitriol; Cancer Vaccines; Diphosphonates; Docetaxel; Drug Resistance, Neoplasm; Endothelin-1; Epothilones; Humans; Male; Oligonucleotides, Antisense; Organoplatinum Compounds; Prostatic Neoplasms; Protease Inhibitors; Protein Kinase Inhibitors; Pyrazines; Taxoids

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

Endothelins are a family of peptide compounds which exert regulatory control over cellular processes important for growth, survival, invasion, and angiogenesis. In particular, endothelin-1, acting primarily through the endothelin-A receptor, is implicated in the neoplastic growth of multiple tumor types. In preclinical models, endothelin antagonism inhibits tumor cell proliferation, invasiveness, and new vessel formation, as well as attenuates osteoblastic and pain-related responses to tumor. Clinical testing of an orally bioavailable endothelin antagonist has demonstrated benefit in PSA progression, markers of bone turnover, and pain in men with prostate cancer, but has not demonstrated significant improvement in survival or time to cancer progression. Although this class of drugs is promising for targeted anti-cancer therapy, their role in treatment remains to be defined by completion of future clinical trials.

Topics: Atrasentan; Bosentan; Clinical Trials as Topic; Endothelin Receptor Antagonists; Endothelin-1; Female; Humans; Male; Neoplasms; Ovarian Neoplasms; Prostatic Neoplasms; Pyrimidines; Pyrrolidines; Receptors, Endothelin; Signal Transduction; Sulfonamides

Bone metastases are highly prevalent in patients with prostate cancer, and they commonly present a therapeutic challenge. The natural history of prostatic bone metastases is characterized by skeletal morbidity, often producing distressing symptoms for individual patients and reducing patient autonomy and mobility. These bone metastases are usually radiologically osteoblastic, but there is also a strong osteolytic component as evidenced by marked increases in bone resorption markers. Malignant bone lesions can reduce the structural integrity of the skeleton, resulting in skeletal complications such as pathologic fracture, spinal cord compression, and severe bone pain, which adversely affect quality of life. Preclinical and clinical studies have provided insight into the pathophysiology of malignant bone disease from prostate cancer and suggest that bone-directed therapies, including radionuclides, endothelin-1 antagonists, and bisphosphonates, may provide both palliative and therapeutic benefits. Clinical investigations with these agents are underway in patients with prostate cancer to gain insight into the pathophysiology of bone metastases and to evaluate the role of bone-specific therapies in treating and preventing bone metastases.

Topics: Androgen Antagonists; Bone Density Conservation Agents; Bone Neoplasms; Bone Resorption; Diphosphonates; Endothelin-1; Humans; Male; Osteoblasts; Osteoclasts; Palliative Care; Prostatic Neoplasms

Progression of hormone-refractory prostate cancer (HRPC) is associated with skeletal complications and bone pain, which contribute to deterioration in quality of life (QOL). The effects of new HRPC therapies on patients' QOL need to be studied. Patient-based assessments that help quantify the risk-benefit profile of HRPC therapies are warranted. This review summarizes the known QOL literature and estimates the potential effect of atrasentan, a novel, selective endothelin A receptor antagonist (SERA), on the QOL of HRPC patients.. Published studies were identified through a structured, detailed literature review. Clinical studies that report QOL data were reviewed, along with recent QOL data from atrasentan studies.. HRPC studies have begun to use QOL assessments as primary endpoints, but different assessments and therapies are not comparable. Very few data integrate QOL with clinical endpoints. Atrasentan clinical trials demonstrated a statistically significant difference in the prostate cancer-specific QOL in favor of atrasentan (p=.032) and an increased quality-adjusted time to progression in men with HRPC.. Atrasentan provides QOL benefits relevant to HRPC. The quality-adjusted analyses applied in the atrasentan studies have begun to lay the foundation for interpreting clinical endpoints in conjunction with QOL. These analyses will facilitate better QOL comparisons within studies and across trials. Further evaluation of atrasentan in HRPC is warranted.

Topics: Atrasentan; Drug Resistance, Neoplasm; Endothelin-1; Gonadal Steroid Hormones; Humans; Male; Neoplasm Metastasis; Prognosis; Prostatic Neoplasms; Pyrrolidines; Quality of Life

This review describes the current state of chemotherapy for androgen-independent prostate cancer. Landmark clinical trials, including TAX 327, a randomized trial comparing docetaxel and prednisone with mitoxantrone and prednisone, and SWOG 9916, a randomized clinical trial comparing docetaxel and estramustine with mitoxantrone and prednisone, are reviewed. Novel combination therapies, involving taxane administered with compounds such as calcitrol and thalidomide, newer cytotoxic agents, vaccine therapies, and targeted modalities are also detailed. This review mainly focuses on agents with activity in phase II/III clinical trials.

Topics: Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Atrasentan; Bevacizumab; Cancer Vaccines; Chemotherapy, Adjuvant; Clinical Trials as Topic; Docetaxel; Endothelin-1; Estramustine; Humans; Male; Mitoxantrone; Prednisone; Prostatic Neoplasms; Pyrrolidines; Randomized Controlled Trials as Topic; Taxoids; Tubulin Modulators; Vascular Endothelial Growth Factor A

Endothelin axis deregulation triggers a series of events that ultimately activates proliferation, invasion, escape from programmed cell death, new vessel formation, abnormal osteogenesis and alteration of nociceptive stimuli. Atrasentan is a novel agent that effectively targets this pathway and is able to inhibit and/or reverse several of these events. Biologic and clinical activity in patients with prostate cancer have been demonstrated in a phase III, placebo-controlled setting by the suppression of markers of biochemical prostate cancer progression and a delay in time to disease progression. Atrasentan may represent a therapeutic option in the management of prostate and other cancers that is worthy of continued investigation.

Topics: Animals; Antineoplastic Agents; Atrasentan; Drug Delivery Systems; Drug Design; Endothelin-1; Humans; Male; Prostatic Neoplasms; Pyrrolidines; Randomized Controlled Trials as Topic

Hormone refractory prostate cancer remains true to its middle name: it is largely refractory to attempts to delay its progression. New targets and new therapies are demanded. Through a review of the available literature on endothelin and several preclinical observations, the endothelin axis has emerged as one such target. In phase II and III clinical trials of atrasentan, a potent and selective endothelin receptor A subtype (ET(A)) antagonist, disease progression was delayed in some men. This well tolerated, oral agent may help convert advanced prostate cancer to a more chronic disease. This review will discuss the endothelin axis, preclinical rationale and some of the available clinical trial data on this promising new approach.

Topics: Apoptosis; Atrasentan; Biomarkers, Tumor; Clinical Trials as Topic; Disease Progression; Endothelin Receptor Antagonists; Endothelin-1; Humans; Male; Prostatic Neoplasms; Pyrrolidines; Receptors, Endothelin; Treatment Outcome

Topics: Alcohol Drinking; Antioxidants; Dose-Response Relationship, Drug; Endothelin-1; Female; Flavonoids; Food, Organic; Heart Diseases; Humans; Lung Neoplasms; Male; Phenols; Polyphenols; Prostatic Neoplasms; Wine

Endothelin axis deregulation triggers a series of events that lead to a profound deregulation in cancer cells, including key tumorigenic cellular events such as proliferation, invasion, escape from programmed cell death, new vessel formation, abnormal osteogenesis and the alteration of nociceptive stimuli. Atrasentan is a novel agent that effectively targets this pathway and is able to inhibit and/or reverse several of those events. Biological and clinical activity in patients with prostate cancer has been demonstrated in a Phase III clinical setting by the suppression of markers of biochemical and clinical prostate cancer progression, and by a delay in time to disease progression, especially in patients with bone disease.

Topics: Atrasentan; Carcinoma; Clinical Trials, Phase III as Topic; Endothelin-1; Humans; Male; Prostatic Neoplasms; Pyrrolidines; Receptor, Endothelin A

Androgen refractory prostate cancer continues to evade effective treatment. The potent vasoconstrictor endothelin-1 is produced by prostate cancer and appears to have a role in prostate cancer progression and morbidity. Background on the endothelin axis (endothelin-1 and endothelin receptors ET(A) and ET(B)), preclinical studies of its role in prostate cancer, results of phases I and II clinical trials, and future directions are reviewed.. A review was conducted of the published data on the endothelin axis in prostate cancer.. Based on preclinical and clinical trial data, the endothelin axis is emerging as potentially important in the biology of prostate cancer progression and morbidity. Drugs targeting the endothelin axis, such as the potent ET(A) receptor antagonist atrasentan (ABT-627), have been studied in large clinical trials and appear to have an impact on disease progression and morbidity.. The role of the endothelin axis in prostate cancer deserves further investigation in the laboratory and clinic. This new strategy for intervention is promising.

Topics: Antineoplastic Agents; Atrasentan; Clinical Trials, Phase I as Topic; Clinical Trials, Phase II as Topic; Endothelin-1; Humans; Male; Prostatic Neoplasms; Pyrrolidines

The endothelins, a family of potent vasoconstricting peptides, have been implicated in the pathophysiology of advanced prostate cancer. Two endothelin receptors, ET-A and ET-B are found in normal prostate tissue. Malignant prostate cells are notable for the loss of ET-B receptors and increased levels of endothelin-1 [ET-1]; this distortion of the endothelin system may be a significant factor in the progression of prostate cancer. Proposed roles for endothelin in prostate cancer include growth promotion, apoptosis inhibition, bone formation, and stimulation of nociceptive receptors. ET-1 can act alone as a mitogen, but its effects are greatest as a comitogen with a variety of growth factors, including basic fibroblast growth factor, insulin-like growth factors, and platelet derived growth factor. Although their exact functions are unclear, ET-1, in conjunction with vascular endothelial growth factor, appears to play a major role in tumor angiogenesis. By a variety of methods, ET-1 alters the balance of osteoblast and osteoclasts to the favor new bone formation that is characteristic of metastatic disease. Several studies indicate that the refractory pain of metastatic cancer is related to the direct nociceptive effects ET-1. These findings suggest that ET receptors are promising therapeutic targets for pharmacologic intervention. Early clinical trials indicate that the ET-A receptor antagonist used in prostate cancer is reasonably well tolerated with mild but pervasive symptoms related to ET-1's vasoconstrictive effects. Results of ongoing clinical trials are eagerly awaited in order to see if the hypothetical promise of ET antagonism will result in clinical success.

Topics: Apoptosis; Endothelin Receptor Antagonists; Endothelin-1; Half-Life; Humans; Male; Neovascularization, Pathologic; Prostatic Neoplasms; Receptors, Endothelin; Tissue Distribution

Prostate growth and development are primarily under the control of androgens; however, other factors can also influence prostatic growth through alternative pathways. This article discusses some of the major nonandrogenic mediators of prostate growth. Information on the pathways by which these factors exert their effects is also reviewed.

Topics: Adenocarcinoma; Androgens; Animals; APUD Cells; Bombesin; Carcinoma, Small Cell; Chromosomes, Human; Cytokines; Endothelin-1; Epidermal Growth Factor; Fibroblast Growth Factors; Growth Substances; Hormones; Humans; Insulin-Like Growth Factor Binding Proteins; Male; Neoplasms, Hormone-Dependent; Organ Specificity; Prostate; Prostatic Neoplasms; Receptors, Fibroblast Growth Factor; Receptors, Growth Factor; Receptors, Transforming Growth Factor beta; Somatomedins; Transforming Growth Factor beta; Tumor Cells, Cultured

Topics: Androgens; Animals; Bombesin; Caveolin 1; Caveolins; Cell Membrane; Endothelin-1; Gastrin-Releasing Peptide; Humans; Male; Membrane Proteins; Neprilysin; Neuropeptides; Neurotensin; Prostatic Neoplasms

Topics: Endothelin-1; Humans; Male; Pain; Prostate; Prostatic Neoplasms; Receptors, Endothelin; Tumor Cells, Cultured

Only 10 years ago, the vasoconstricting peptide endothelin was discovered; it is produced by endothelial cells. Different isoforms and receptors of endothelin have been identified. The effects of endothelin-I, the most important isoform, are mainly vasoconstriction and proliferation of cells. In the last few years endothelin receptor antagonists have become available, which can delineate the clinical importance of the endothelin system. Possible indications for endothelin receptor blockers are renal disease (acute and chronic renal failure) and cardiovascular disease (heart failure; restenosis after percutaneous transluminal coronary angioplasty (PTCA); pulmonary hypertension; systemic hypertension). There is also a possible role for endothelin receptor blockers in oncology (prostatic carcinoma). Currently clinical trials are being carried out to determine the efficacy of these compounds for the above-mentioned indications.

Topics: Cardiovascular Diseases; Endothelin Receptor Antagonists; Endothelin-1; Endothelins; Female; Humans; Kidney Diseases; Male; Prostatic Neoplasms; Receptors, Endothelin

Endothelin-1 and the endothelin A (ET(A) ) receptor have been implicated in prostate cancer progression in bone. This study aimed to determine whether the specific ET(A) receptor antagonist, zibotentan, prolonged overall survival (OS) in patients with castration-resistant prostate cancer and bone metastases who were pain-free or mildly symptomatic for pain.. Patients were randomized 1:1 to zibotentan 10 mg/day or placebo, plus standard prostate cancer treatment. The primary endpoint was OS. Secondary endpoints included times to pain progression, chemotherapy use, new bone metastases, and safety. Efficacy endpoints were analyzed using a log-rank test.. A total of 594 patients were randomized (zibotentan, n = 299; placebo, n = 295). Median OS was 24.5 months in zibotentan-treated patients versus 22.5 months for placebo, but the difference did not reach statistical significance (hazard ratio, 0.87; 95.2% confidence interval, 0.69-1.10; P = .240). No statistically significant differences were observed for any secondary efficacy endpoints. Peripheral edema (44%) and headache (31%) were the most commonly reported adverse events in the zibotentan group. Cardiac failure events were higher in the zibotentan group than placebo (any grade, 5.7% and 1.7%; Common Terminology Criteria for Adverse Events grade ≥3, 3.0% and 1.0%, respectively); these were manageable and reversible.. In this large, randomized, placebo-controlled phase 3 trial, treatment with zibotentan 10 mg/day did not lead to a statistically significant improvement in OS in this patient population. Zibotentan had an acceptable safety profile.

Topics: Antineoplastic Agents; Bone Neoplasms; Disease-Free Survival; Endothelin A Receptor Antagonists; Endothelin-1; Humans; Male; Orchiectomy; Placebos; Prostatic Neoplasms; Pyrrolidines; Survival; Treatment Outcome

Atrasentan is a potent, oral, selective endothelin-A (ET(A)) receptor antagonist that has clinical activity in patients with hormone-refractory prostate cancer (HRPC). In this article, the authors report the results from a phase 3, randomized, double-blind, placebo-controlled trial of atrasentan in patients with nonmetastatic HRPC.. Of 941 patients who had adequate androgen suppression and no radiographic evidence of metastases but rising prostate-specific antigen (PSA) levels, 467 patients were randomized to receive atrasentan at a dose of 10 mg, and 474 patients were randomized to receive placebo daily. The primary endpoint was the time to disease progression (TTP), which was defined as the onset of metastases. Secondary endpoints were the time to PSA progression, change in bone alkaline phosphatase (BALP) levels, PSA doubling time, and overall survival.. There was a 93-day delay in the median TTP with atrasentan, but the difference from placebo in TTP was not statistically significant (P= .288). Large geographic differences in the median TTP were noted: in the US: The difference was 81 days longer with placebo; whereas, in non-US sites, the difference was 180 days longer with atrasentan. Atrasentan lengthened the PSA doubling time (P= .031) and slowed the increase in BALP (P< .001). The median survival was 1477 days with atrasentan and 1403 days with placebo. The most common adverse events associated with atrasentan were peripheral edema, nasal congestion, and headache, consistent with the vasodilatory properties of ET(A) receptor antagonists.. Although the primary endpoint was not achieved, large regional differences in TTP were noted, suggesting that trial conduct may have influenced the results. The biologic activity was consistent with findings from other clinical trials of atrasentan in HRPC.

Topics: Administration, Oral; Aged; Aged, 80 and over; Alkaline Phosphatase; Atrasentan; Disease Progression; Double-Blind Method; Endothelin-1; Humans; Male; Middle Aged; Neoplasms, Hormone-Dependent; Placebos; Prognosis; Prostatic Neoplasms; Pyrrolidines; Treatment Outcome

We examined the effects of atrasentan (endothelin-A receptor antagonist) on bone deposition and resorption markers and on bone scan index.. This double-blind, randomized, placebo controlled clinical trial of hormone refractory prostate cancer patients was done at 74 medical centers in the United States and Europe. A total of 288 asymptomatic patients with hormone refractory prostate adenocarcinoma and evidence of metastatic disease were randomized to 1 of 3 treatment groups, namely 2.5 mg. atrasentan, 10 mg. atrasentan or placebo administered orally daily until disease progression. The main outcomes measures were changes in bone deposition markers (total alkaline phosphatase and bone alkaline phosphatase) and bone resorption (N-telopeptides, C-telopeptides and deoxypyridinoline), and in the bone scan index.. At baseline markers of bone deposition and resorption were elevated 1.4 to 2.7-fold above respective upper limits of normal. Subjects receiving placebo experienced a 58% elevation in mean total alkaline phosphatase and a 99% elevation in mean bone alkaline phosphatase (p < 0.001), whereas subjects receiving 10 mg. atrasentan maintained stable mean total alkaline phosphatase and bone alkaline phosphatase values compared with baseline. N-telopeptides, C-telopeptides and deoxypyridinoline elevation from baseline were consistently less in patients receiving 10 mg. atrasentan compared with placebo. Similar trends were observed in subjects who received 2.5 mg. atrasentan. Changes in clinical bone scan studies paralleled bone marker changes.. Atrasentan suppressed markers of biochemical and clinical prostate cancer progression in bone and demonstrates clinical activity for hormone refractory prostate cancer.

Topics: Adenocarcinoma; Aged; Alkaline Phosphatase; Amino Acids; Antineoplastic Agents; Atrasentan; Biomarkers, Tumor; Bone Remodeling; Bone Resorption; Collagen; Collagen Type I; Double-Blind Method; Endothelin-1; Humans; Male; Peptides; Prostatic Neoplasms; Pyrrolidines

Topics: Atrasentan; Disease Progression; Double-Blind Method; Endothelin-1; Humans; Male; Neoplasm Metastasis; Pain; Prostate-Specific Antigen; Prostatic Neoplasms; Pyrrolidines; Quality of Life; Survival Analysis; Treatment Outcome

Topics: Administration, Oral; Aged; Antineoplastic Agents, Hormonal; Atrasentan; Disease Progression; Dose-Response Relationship, Drug; Drug Administration Schedule; Drug Resistance, Neoplasm; Endothelin-1; Follow-Up Studies; Humans; Male; Neoplasm Staging; Prostatic Neoplasms; Pyrrolidines; Quality of Life; Risk Assessment; Treatment Outcome

Vimentin3 (Vim3) was recently described as a tumour marker for the direct discrimination between benign and malignant kidney tumours. Here, we examined its expression in prostate cancer (PCa) cell lines and the regulation of its expression by endothelin receptors.. Prostate cancer cell lines (PC3, DU145, LNCap) were incubated with endothelin 1 (ET-1), BQ123 [endothelin A receptor (ETAR) antagonist], BQ788 [endothelin B receptor (ETBR) antagonist], BQ123+ET-1, BQ788+ET-1 for 24 h and a scratch assay was performed. Cell extracts were analysed by western blotting and qRT-PCR.. ET-1 induced Vim3 overexpression. Blocking the ETBR in the different prostate cancer cell lines yielded a higher migration rate, whereby Vim3 expression was significantly increased.. Vim3 concentration increases in cell lines without a functional ETBR and may be used as a marker for PCas where ETBR is frequently methylated.

Topics: Biomarkers, Tumor; Cell Line, Tumor; Cell Movement; Cells, Cultured; Endothelin-1; Gene Expression; Humans; Male; Prostatic Neoplasms; Vimentin

Endothelin‑1 (ET‑1) is involved in the regulation of steroidogenesis. Additionally, patients with castration‑resistant prostate cancer (PCa) have a higher ET‑1 plasma concentration than those with localized PCa and healthy individuals. The aim of the present study was to evaluate the effect of ET‑1 on steroidogenesis enzymes, androgen receptor (AR) and testosterone (T) production in PCa cells. The expression levels of endothelin receptors in prostate tissue from patients with localized PCa by immunohistochemistry, and those in LNCaP and PC3 cells were determined reverse transcription‑quantitative PCR (RT‑qPCR) and western blotting. Furthermore, the expression levels of ET‑1 were determined in LNCaP and PC3 cells by RT‑qPCR and western blotting. The ET‑1 receptor activation was evaluated by intracellular calcium measurement, the expression levels of AR and enzymes participating in steroidogenesis [cytochrome P450 family 11 subfamily A member 1 (CyP11A1), cytochrome P450 family 17 subfamily A member 1, aldo‑keto reductase family member C2 and 3β‑hydroxysteroid dehydrogenase/isomerase 2 (3β HSD2)] were determined by western blotting and T concentration was determined by ELISA using PC3 cells. The present results revealed higher expression levels of endothelin A receptor (ET

Topics: 3-Hydroxysteroid Dehydrogenases; Aged; Aged, 80 and over; Cell Line, Tumor; Cholesterol Side-Chain Cleavage Enzyme; Endothelin-1; Humans; Male; Middle Aged; Neoplasm Grading; PC-3 Cells; Prostatic Neoplasms; Receptor, Endothelin A; Receptor, Endothelin B; Receptors, Androgen; Testosterone; Tissue Array Analysis; Up-Regulation

Bone metastasis is a painful complication of advanced prostate cancer. Endothelin-1 is a tumor-secreted factor that plays a central role in osteoblast activation and the osteosclerotic response of prostate cancer metastatic to bone. Antagonists that block the activation of the endothelin A receptor (ETAR), located on osteoblasts, reduce osteoblastic bone lesions in animal models of bone metastasis. However, ETAR antagonists demonstrated limited efficacy in clinical trials of men with advanced prostate cancer who also received standard androgen deprivation therapy (ADT). Previous data from our group suggested that, in a mouse model, ETAR antagonists might only be efficacious when androgen signaling in the osteoblast is lowered beyond the ability of standard ADT. This notion was tested in a mouse model of prostate cancer bone metastasis. Castrated and sham-operated male athymic nude mice underwent intracardiac inoculation of the ARCaPM castration-resistant prostate cancer cell line. The mice were then treated with either the ETAR antagonist zibotentan or a vehicle control to generate four experimental groups: vehicle+sham (Veh+Sham), vehicle+castrate (Veh+Castr), zibotentan+sham (Zibo+Sham), and zibotentan+castrate (Zibo+Castr). The mice were monitored radiographically for the development of skeletal lesions. The Zibo+Castr group had significantly longer survival and a single incidental lesion. Mice in the Zibo+Sham group had the shortest survival and the largest number of skeletal lesions. Survival and skeletal lesions of the Veh+Sham and Veh+Castr groups were intermediate compared with the zibotentan-treated groups. We report a complex interaction between ETAR and androgen signaling, whereby ETAR blockade was most efficacious when combined with complete androgen deprivation.

Topics: Animals; Bone Neoplasms; Cell Line, Tumor; Disease Models, Animal; Endothelin A Receptor Antagonists; Endothelin-1; Male; Mice; Orchiectomy; Osteoblasts; Prostatic Neoplasms; Pyrrolidines; Receptor, Endothelin A

Topics: 3T3 Cells; Animals; Bone Neoplasms; CCN Intercellular Signaling Proteins; Cell Adhesion; Cell Line, Tumor; Cell Movement; Coculture Techniques; Culture Media, Conditioned; Endothelin-1; Gene Expression Regulation, Neoplastic; Humans; Integrin alpha4beta1; Male; Mice; Neoplasm Transplantation; Osteoblasts; Osteogenesis; Prostatic Neoplasms; Proto-Oncogene Proteins; RAW 264.7 Cells; Signal Transduction; Vascular Cell Adhesion Molecule-1

Prostate cancers have a strong propensity to metastasize to bone and promote osteoblastic lesions. TMPRSS2:ERG is the most frequent gene rearrangement identified in prostate cancer, but whether it is involved in prostate cancer bone metastases is largely unknown. We exploited an intratibial metastasis model to address this issue and we found that ectopic expression of the TMPRSS2:ERG fusion enhances the ability of prostate cancer cell lines to induce osteoblastic lesions by stimulating bone formation and inhibiting the osteolytic response. In line with these in vivo results, we demonstrate that the TMPRSS2:ERG fusion protein increases the expression of osteoblastic markers, including Collagen Type I Alpha 1 Chain and Alkaline Phosphatase, as well as Endothelin-1, a protein with a documented role in osteoblastic bone lesion formation. Moreover, we determined that the TMPRSS2:ERG fusion protein is bound to the regulatory regions of these genes in prostate cancer cell lines, and we report that the expression levels of these osteoblastic markers are correlated with the expression of the TMPRSS2:ERG fusion in patient metastasis samples. Taken together, our results reveal that the TMPRSS2:ERG gene fusion is involved in osteoblastic lesion formation induced by prostate cancer cells.

Topics: Alkaline Phosphatase; Animals; Biomarkers, Tumor; Bone Neoplasms; Cell Line, Tumor; Collagen Type I, alpha 1 Chain; Endothelin-1; Gene Expression Regulation, Neoplastic; Humans; Male; Mice, SCID; Oncogene Proteins, Fusion; Osteoblasts; PC-3 Cells; Phenotype; Prostatic Neoplasms; Transplantation, Heterologous; Tumor Burden

Androgen deprivation is often the treatment of choice for patients with a new diagnosis of metastatic or locally advanced prostate cancer (CaP). However, most CaP patients showing a first response to androgen deprivation will progress to a hormone refractory phase of the disease (HRPC) with a much poorer prognosis. Accumulating evidence suggests that endothelin-1 (ET-1) plays an important role in CaP progression. Singlenucleotide polymorphisms (SNPs) of the ET-1 gene reportedly have been associated with cancer progression and chemoresistance. In the present study, we explored the association of SNPs and haplotypes of the ET-1 gene with the risk of HRPC. We genotyped three SNPs (rs1800541, rs2070699 and rs5370) in the ET-1 gene in a case-control study; 234 CaP patients who developed HRPC within six years after androgen deprivation therapy was used as HRPC cases, and 234 age- and primary therapy-matched CaP patients who had not developed HRPC within six years after androgen deprivation therapy were used as non-HRPC controls. Our results revealed that the G allele at rs1800541 and the G allele at rs2070699 were respectively associated with reduced and increased risk of HRPC at borderline statistical significance (p=0.047 and p=0.058, respectively). With adjustment for potential confounders including body mass index, initial Gleason score at diagnosis of CaP, and post-treatment nadir serum PSA level, we found that rs1800541-rs2070699 TG haplotype was significantly associated with increased risk of HRPC (p=0.033; adjusted OR, 2.10; 95% CI, 1.37-5.04). In conclusion, this study provides the first evidence that a 2-SNP haplotype of the ET-1 gene is associated with increased risk of HRPC, which adds new insights into early identification of CaP patients who are likely to develop HRPC in a later stage of the disease.

Topics: Aged; Alleles; Androgen Antagonists; Case-Control Studies; Disease Progression; Drug Resistance, Neoplasm; Endothelin-1; Genotype; Haplotypes; Humans; Male; Middle Aged; Polymorphism, Single Nucleotide; Prostate-Specific Antigen; Prostatic Neoplasms

Endothelin-1 and Endostar are both significant for the progression, proliferation, metastasis and invasion of cancer. In this paper, we studied the effect of ET-1 RNAi and Endostar in PC-3 prostatic cancer cells.. The lentiviral vector was used in the establishment of ET-1 knockdown PC-3 cells. Progression and apoptosis were assessed by CKK-8 and flow cytometry, respectively. Transwell assay was used to estimate invasion and signaling pathways were studied by Western blotting.. ET-1 mRNA and protein in ET-1 knockdown PC-3 cells were reduced to 26.4% and 22.4% compared with control group, respectively. ET-1 RNAi and Endostar both were effective for the suppression of progression and invasion of PC-3 cells. From Western blotting results, the effects of ET-1 regulation and Endostar on PC-3 cells were at least related to some signaling pathways involving PI3K/Akt/Caspase-3, Erk1/2/Bcl-2/Caspase-3 and MMPs (MMP-2 and MMP-9). Furthermore, combined treatment of ET-1RNAi and Endostar was found to be more effective than single treatment.. Both ET-1 RNAi and Endostar can inhibit the progression and invasion of PC-3 cells, but combined treatment might be a better therapeutic schedule.

Topics: Apoptosis; Caspase 3; Cell Line, Tumor; Cell Proliferation; Endostatins; Endothelin-1; Gene Expression Regulation; Gene Knockdown Techniques; Humans; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Neoplasm Invasiveness; Phosphatidylinositol 3-Kinases; Prostatic Neoplasms; Proto-Oncogene Proteins c-akt; Recombinant Proteins; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; RNA, Small Interfering

Approximately 90% of patients who die of Prostate Cancer (PCa) have bone metastases, which promote a spectrum of osteoblastic, osteolytic or mixed bone responses. Numerous secreted proteins have been reported to promote osteoblastic or osteolytic bone responses. We determined whether previously identified and/or novel proteins were associated with the osteoblastic or osteolytic response in clinical specimens of PCa bone metastases.. Gene expression was analyzed on 14 PCa metastases from 11 patients by microarray profiling and qRT-PCR, and protein expression was analyzed on 33 PCa metastases from 30 patients by immunohistochemistry on highly osteoblastic and highly osteolytic bone specimens.. Transcript and protein levels of BMP-2, BMP-7, DKK-1, ET-1, and Sclerostin were not significantly different between osteoblastic and osteolytic metastases. However, levels of OPG, PGK1, and Substance P proteins were increased in osteoblastic samples. In addition, Emu1, MMP-12, and sFRP-1 were proteins identified with a novel role of being associated with either the osteoblastic or osteolytic bone response.. This is the first detailed analysis of bone remodeling proteins in human specimens of PCa bone metastases. Three proteins not previously shown to be involved may have a role in the PCa bone response. Furthermore, our data suggests that the relative expression of numerous, rather than a single, bone remodeling proteins determine the bone response in PCa bone metastases.

Topics: Aged; Bone Morphogenetic Proteins; Bone Neoplasms; Bone Remodeling; Endothelin-1; Gene Expression; Humans; Immunohistochemistry; Intercellular Signaling Peptides and Proteins; Male; Neoplasm Proteins; Osteoblasts; Osteolysis; Phosphoglycerate Kinase; Prostatic Neoplasms; Substance P

Pathological endothelin axis is known to be involved in prostate cancer progression. Our study evaluates immunohistochemical expression of ET-1 and ET-AR on prostate biopsy specimen and the predictive value for biochemical relapse on patients with advanced and metastatic cancer. We also evaluated the impact of ET-1 and ET-AR expression on local progression and metastatic bone progression for these patients.. From 1992 to June 2009, 44 patients with clinical T3 stage and metastatic lymph nodes were included. PSA levels, Gleason score in biopsy cores, number of invaded lymph nodes, the existence of nodular capsule transgression and hormonal treatment given to the patient, were analyzed. Biopsy cores were submitted to immunohistochemical study of the expression of ET-1 and ET-AR. Semi-quantitative ET-1 and ET-AR staining assessment was always realised by the same pathologist.. The average age of the cohort was 65.6 (standard deviation 6.3), median PSA level was 52.8 ng /ml (3-227), median time of follow-up was 70 months (6-144). Biochemical relapse was observed in 62.8%. Statistically significant stronger ET-1 expression was observed in biopsies of patients with a biochemical relapse (p=0.014). Eighty percent of patients with a biochemical relapse had a high level of ET-AR expression, but no statistical significance has been shown (p=0.109). The relative risk for progression under hormonal therapy was 1.9 in case of high level of ET-1 expression and biochemical relapse was confirmed 8 months earlier in average. High level of ET-AR expression on biopsy cores may indicate earlier local progression and metastatic bone progression but there were no statistical proof.. In our study, the strength of ET-1 expression in prostate cancer biopsy cores is a prognostic factor of biochemical relapse for cT3 stage patients with metastatic lymph nodes. We have not been able to prove that ET-1 is an independent prognostic factor. A high level of ET-AR expression on prostate biopsy cores is not, in our study, a prognosis factor for predicting the biochemical relapse.

Topics: Aged; Biopsy; Endothelin-1; Humans; Immunohistochemistry; Lymphatic Metastasis; Male; Neoplasm Recurrence, Local; Prognosis; Prostate; Prostatic Neoplasms; Receptor, Endothelin A

Neuropeptides are important signal initiators in advanced prostate cancer, partially acting through activation of nuclear factor kappa B. Central to nuclear factor kappa B regulation is the ubiquitin-proteasome system, pharmacological inhibition of which has been proposed as an anticancer strategy. We investigated the putative role of the proteasome inhibitor bortezomib in neuropeptides signaling effects on prostate cancer cells.. Human prostate cancer cell lines, LNCaP and PC-3, were used to examine cell proliferation, levels of proapoptotic (caspase-3, Bad) and cell cycle regulatory proteins (p53, p27, p21), as well as total and phosphorylated Akt and p44/42 mitogen-activated protein kinase proteins. Furthermore, 20S proteasome activity, subcellular localization of nuclear factor kappa B and transcription of nuclear factor kappa B target genes, interleukin-8 and vascular endothelial growth factor, were assessed.. Neuropeptides (endothelin-1, bombesin) increased cell proliferation, whereas bortezomib decreased proliferation and induced apoptosis, an effect maintained after cotreatment with neuropeptides. Bad, p53, p21 and p27 were downregulated by neuropeptides in PC-3, and these effects were reversed with the addition of bortezomib. Neuropeptides increased proteasomal activity and nuclear factor kappa B levels in PC-3, and these effects were prevented by bortezomib. Interleukin-8 and vascular endothelial growth factor transcripts were induced after neuropeptides treatment, but downregulated by bortezomib. These results coincided with the ability of bortezomib to reduce mitogen-activated protein kinase signaling in both cell lines.. These findings are consistent with bortezomib-mediated abrogation of neuropeptides-induced proliferative and antiapoptotic signaling. Thus, the effect of the drug on the neuropeptides axis needs to be further investigated, as neuropeptide action in prostate cancer might entail involvement of the proteasome.

Topics: Antineoplastic Agents; Apoptosis; bcl-Associated Death Protein; Bombesin; Boronic Acids; Bortezomib; Cell Line, Tumor; Cell Proliferation; Cyclin-Dependent Kinase Inhibitor p21; Cyclin-Dependent Kinase Inhibitor p27; Down-Regulation; Endothelin-1; Humans; Interleukin-8; Male; Mitogen-Activated Protein Kinases; NF-kappa B; Prostatic Neoplasms; Proteasome Endopeptidase Complex; Pyrazines; RNA, Messenger; Signal Transduction; Translocation, Genetic; Tumor Suppressor Protein p53; Vascular Endothelial Growth Factor A

To assess the value of endothelin-1 (ET-1) expression in predicting extracapsular extension (ECE) in clinically localized prostate cancer (PCa).. ET-1 expression was determined by immunohistochemistry on archival needle biopsies (NBs) from 94 patients (49 pT2 and 45 pT3a) who underwent radical prostatectomy (RP) for clinical T1-T2 PCa. Each sample was analysed independently by two pathologists blinded to the clinical data.. In univariate analysis, high ET-1 expression in NBs, pre-operative prostate-specific antigen (PSA) level >10 ng/ml, percentage of positive biopsy cores and NB Gleason score ≥7 were significantly associated with ECE as determined on subsequent RP. No significant association was found between clinical stage and ECE. In multivariate analysis, there was a significant association with high ET-1 expression in NBs (p = 0.006), pre-operative PSA level >10 ng/ml (p = 0.049), and NB Gleason score ≥7 (p = 0.002). These three pre-operative factors combined provided the best model for predicting ECE with 93.3% sensitivity, 49% specificity, 62.5% positive predictive value, 88.9% negative predictive value. The combination yielded a higher concordance index (0.760 vs 0.720) and offered a higher log partial likelihood than the same model without ET1 (112.8 vs 105.7, p = 0.01).. ET-1 expression was strongly associated with ECE and, when combined with pre-operative PSA level and Gleason score, improved the predictive accuracy of pre-operative NBs. Its assessment in patients with localized PCa might be useful when making treatment decisions. Further studies with standardisation of immunohistochemical staining and multi-institutional validation are now needed to establish the appropriate use of ET-1 staining in PCa staging and to evaluate inter-observer reproducibility.

Topics: Adenocarcinoma; Aged; Biopsy, Needle; Endothelin-1; Humans; Immunohistochemistry; Male; Middle Aged; Neoplasm Invasiveness; Neoplasm Staging; Predictive Value of Tests; Prostate; Prostatic Neoplasms; Sensitivity and Specificity

We investigated whether serum markers of angiogenesis endothelin-1 (ET-1) and tissue factor (TF), and/or markers of vascular damage such as circulating endothelial cells (CECs), or their relative changes during treatment, were prognostic for overall survival (OS) in castration resistant prostate cancer (CRPC) patients. Additionally, we combined these markers with circulating tumour cells (CTCs) to construct a predictive nomogram for treatment outcome.. One hundred and sixty two CRPC patients treated with a docetaxel containing regimen had blood drawn before and at 2-5 weeks and 6-8 weeks after treatment start. Prospectively determined CTC and CEC levels, and retrospectively measured serum concentrations of ET-1 (pg/mL) and TF (pg/mL) were evaluated to determine their prognostic value for OS.. Baseline CEC, TF and ET-1 were not prognostic for OS. A > or = 3.8-fold increase in CEC 2-5 weeks after treatment initiation was associated with decreased OS (median 10.9 versus 16.8 months; P=0.015), as was any decrease in TF levels compared to baseline levels (median 11.9 versus 21.5 months; P=0.0005). As previously published, baseline and CTC counts > or = 5 at 2-5 weeks were also predictive of decreased OS. Combining CTC with changes in TF and CEC 2-5 weeks after treatment initiation yielded four groups differing in OS (median OS 24.2 versus 16.0 versus 11.4 versus 6.1 months; P<0.0001).. CEC, CTC and TF levels alone and combined can predict early on OS in CRPC patients treated with docetaxel-based therapy. A prospective study to confirm the use of these markers for patient management is needed.

Topics: Aged; Aged, 80 and over; Androgen Antagonists; Antineoplastic Agents; Biomarkers, Tumor; Docetaxel; Endothelin-1; Enzyme-Linked Immunosorbent Assay; Humans; Male; Middle Aged; Neoplastic Cells, Circulating; Neovascularization, Pathologic; Orchiectomy; Prospective Studies; Prostatic Neoplasms; Survival Analysis; Taxoids; Thromboplastin; Treatment Outcome

The study evaluated the immunohistochemistry expression of endothelin-1 (ET-1) by prostate cancer (PCa) in prostate biopsies as an extracapsular stage (pT3a) prognostic factor.. Sixty-eight radical prostatectomies (RP) were performed for clinically localised PCa (35 pT2 and 33 pT3a according to the 2002 pTNM classification). Age, digital rectal examination, initial PSA, biopsy Gleason score, positive biopsies ratio, specimen Gleason score, biopsy and RP specimen perineural neoplasic invasion, PCa DNA ploidy, PCa Ki-67 DNA image cytometry and biopsy and RP specimen ET-1 immunohistochemistry expression for both group were compared. Semi-quantitative ET-1 staining assessment was realised by the same pathologist.. pT3a group initial PSA was higher (p=0.032). No statistically difference was noticed between pT2 and pT3a groups for positive biopsies ratio, biopsy perineural neoplastic invasion and biopsy DNA ploidy determination. Biopsy Gleason score > or =7 was predictive of a pT3a stage (p=0.03). Statistically higher intensity of ET-1 PCa expression was observed in biopsies and specimens in pT3a group than in pT2 group (p<0.001 and p=0.01). In multivariate analysis, biopsy ET-1 PCa expression was an independent risk factor of pT3a stage with specificity 79 %, sensibility 69 %, predictive positive value 77 % and negative positive value 72 %. Combined with initial PSA > or =7, values were respectively 100 %, 76.9 %, 100 % and 57.1 %.. Endothelin-1 (ET-1) prostate cancer biopsy expression in our study was an independent prognostic factor of extracapsular stage (pT3a). Further studies will assess the relevance of ET-1 expression study in clinically localised PCa for active surveillance, curative treatment or targeted adjuvant therapy management.

Topics: Endothelin-1; Humans; Immunohistochemistry; Male; Middle Aged; Neoplasm Staging; Prognosis; Prostatic Neoplasms; Retrospective Studies

We investigated the clinical significance of chromogranin A and endothelin-1 polymorphism and expression in prostate cancer.. We analyzed 2 CHGA polymorphisms by polymerase chain reaction-restriction fragment length polymorphism in DNA samples of 435 patients with prostate cancer and 316 age matched male controls. Chromogranin A and endothelin-1 expression was evaluated by immunohistochemistry in prostate specimens of 114 men with prostate cancer who underwent radical retropubic prostatectomy and in 27 with bladder cancer who underwent radical cystectomy and served as controls.. For the CHGA Glu264Asp polymorphism men with the GG genotype were at 2.05 times higher risk for prostate cancer than men with the CC genotype (p = 0.014). In men with prostate cancer higher chromogranin A immunohistochemistry grade was associated with higher stage and higher Gleason score (p = 0.011 and 0.044, respectively). Multivariate analysis showed that chromogranin A immunohistochemistry grade was an independent variable for predicting biochemical failure after radical prostatectomy (p = 0.023). Higher endothelin-1 expression was observed in prostate cancers (p = 0.011), especially those with a higher Gleason score (p = 0.042). There was no significant relationship between chromogranin A polymorphisms, and chromogranin A and endothelin-1 expression.. Polymorphism and expression of chromogranin A and endothelin-1 have clinical significance in prostate cancer. Chromogranin A expression was an independent predictor of biochemical failure after prostatectomy in patients with localized prostate cancer.

Topics: Aged; Chromogranin A; Endothelin-1; Humans; Male; Polymorphism, Genetic; Prostatic Neoplasms

Plasma concentrations of the mitogenic peptide endothelin-1 (ET-1) are significantly elevated in men with metastatic prostate cancer (PC). ET-1 also contributes to the transition of hormonally regulated androgen-dependent PC to androgen-independent disease. ET-1 is generated from big-ET-1 by endothelin-converting enzyme (ECE-1). ECE-1 is present in PC cell lines and primary tissue and is elevated in primary malignant stromal cells compared with benign. siRNA or shRNA-mediated knockdown of endogenous ECE-1 in either the epithelial or stromal compartment significantly reduced PC cell (PC-3) invasion and migration. The re-addition of ET-1 only partially recovered the effect, suggesting ET-1-dependent and -independent functions for ECE-1 in pPC. The ET-1-independent effect of ECE-1 on PC invasion may be due to modulation of downstream signalling events. Addition of an ECE-1 specific inhibitor to PC-3 cells reduced phosphorylation of focal adhesion kinase (FAK), a signalling molecule known to play a role in PC. siRNA-mediated knockdown of ECE-1 resulted in a significant reduction in FAK phosphorylation. Accordingly, transient ECE-1 overexpression in PNT1-a cells increased FAK phosphorylation. In conclusion, ECE-1 influences PC cell invasion via both ET-1-mediated FAK phosphorylation and ET-1 independent mechanisms.

Topics: Aspartic Acid Endopeptidases; Cell Line, Tumor; Endothelin-1; Endothelin-Converting Enzymes; Focal Adhesion Kinase 1; Gene Expression; Humans; Isoenzymes; Male; Metalloendopeptidases; Neoplasm Invasiveness; Neprilysin; Phosphorylation; Prostatic Neoplasms; Protease Inhibitors; RNA, Small Interfering; Transfection

Increasing evidence suggests that androgen independent prostate cancer (PC) maintains a functional androgen receptor (AR) pathway despite the low levels of circulating androgen following androgen withdrawal, the molecular mechanisms of which are not well defined yet. To address this question, we investigated the effects of endothelin-1 (ET-1) on AR expression. Western analysis and RT-PCR revealed that in the presence of ET-1, levels of AR significantly increased in a time- and dose-dependent manner in LNCaP cells. Pretreatments with inhibitors of Src and phosphoinositide kinase 3 (PI-3K) suppressed ET-1-induced AR expression. As ET-1 was reported to cause a transient increase in c-myc mRNA levels, we examined the involvement of c-myc in ET-1-mediated AR expression. Transient transfection of c-myc siRNA neutralized ET-1-induced AR expression, suggesting that AR induction by ET-1 is c-myc dependent. AR can regulate the transcription of its own gene via a mechanism in which c-myc plays a crucial role. Therefore, we assessed if ET-1-induced-c-myc leads to the enhancement of AR transcription. Reporter gene assays using the previously identified AR gene enhancer containing a c-myc binding site were conducted in LNCaP cells. We found that ET-1 induced reporter gene activity from the construct containing the wild-type but not mutant c-myc binding site. Chromatin immunoprecipitation assays confirmed that ET-1 increased interaction between c-myc and c-myc binding sites in AR enhancer, suggesting that ET-1-induced AR transcription occurs via c-myc-mediated AR transcription. Together, these data support the notion that ET-1, via Src/PI-3K signaling, augments c-myc expression leading to enhanced AR expression in PC.

Topics: Base Sequence; Blotting, Western; Cell Line, Tumor; Chromatin Immunoprecipitation; DNA Primers; Endothelin-1; Genes, myc; Humans; Male; Phosphatidylinositol 3-Kinases; Prostatic Neoplasms; Receptors, Androgen; Reverse Transcriptase Polymerase Chain Reaction

The vasoactive peptide endothelin-1 (ET-1) has been implicated in promoting the progression of prostate and other cancers though its precise mechanism(s)-of-action remain unclear. To better define the role of ET-1 in prostate cancer progression, we generated prostate cancer cell lines (PC-3 and 22Rv1) that express elevated levels of ET-1. As anticipated, increased ET-1 lead to modest autocrine growth stimulation of PC-3 cells in monolayer culture and increased colony formation in soft agar by both cell lines. Unexpectedly, however, metastatic colonization of 22Rv1 cells expressing elevated levels of ET-1 was reduced, as was the size of subcutaneous tumors produced by both 22Rv1- and PC-3 cells. Based on these data, we hypothesized that high levels of ET-1 may negatively impact the tumor microenvironment. We found that increased ET-1 expression did not consistently inhibit angiogenesis, indicating that this was not the cause of poor tumor growth. As an alternative explanation, we examined whether elevated ET-1 results in local vasoconstriction and thus reduces the blood supply available to the tumor. Consistent with this hypothesis, treatment of mice bearing PC-3 xenografts with a vasodilator increased tumor perfusion and partially restored tumor growth. Moreover, analysis of tumor vascular casts indicated vasoconstriction of tumor-feeding arterioles. Taken together, our data suggest that the local concentration of the ET-1 peptide is critical for determining a balance between its previously unrecognized tumor growth-suppressing activity (vasoconstriction) and known growth-promoting (mitogenesis, survival and angiogenesis) activities. These findings may have implications for the modification of current prostate cancer therapies involving ET-1.

Topics: Animals; Arterioles; Endothelin-1; Male; Mice; Neovascularization, Pathologic; Prostatic Neoplasms; Vasoconstriction

To investigate the prognostic value of endothelin-1 (ET-1), a vasoconstrictor involved in differentiation and growth of cancer, in prostate cancer.. A tissue microarray was constructed of 287 prostate cancers from radical prostatectomy (RP) specimens with median follow-up of 48.9 months. Slides were immunostained for ET-1. Intensity and extent of immunoreactivity and their product (IRp) were evaluated. We separately arrayed benign prostatic tissue, atrophy, high grade prostatic intraepithelial neoplasia (HGPIN) and prostate cancer from 40 men.. ET-1 expression was stronger in both HGPIN and cancer than in benign tissue (p < 0.001). The intensity and the IRp of ET-1 predicted biochemical recurrence (p < 0.001 and p = 0.044, respectively), while the staining extent showed no significant correlation with outcome (p = 0.68). Recurrence-free survival in patients with strong ET-1 staining was shorter than in those with weaker expression (hazard ratio [CI 95%] 2.44 [1.55-3.84], p < 0.001). In a multivariate analysis including ET-1 expression, preoperative serum prostate-specific antigen (PSA), extraprostatic extension, margin status, seminal vesicle invasion and Gleason score, only PSA, margins and Gleason score remained significant.. ET-1 is overexpressed in localized prostate cancer and predicts outcome after RP in univariate analysis.

Topics: Adult; Aged; Biomarkers, Tumor; Endothelin-1; Follow-Up Studies; Humans; Male; Middle Aged; Multivariate Analysis; Neoplasm Recurrence, Local; Prostatic Neoplasms; Survival Analysis; Tissue Array Analysis

Topics: Atrasentan; Endothelin-1; Humans; Male; Neoplasms, Hormone-Dependent; Prostatic Neoplasms; Pyrrolidines

To investigate the expressions of VEGF in prostate cancer (PCa) and benign prostatic hyperplasia (BPH), their clinical significance and their relationship with that of ET-1.. A total of 44 specimens of PCa and 36 of BPH tissues were examined by the immunohistochemical Elivision plus method for the expressions of VEGF and ET-1. The intensity of staining for VEGF and ET-1 was assessed by light microscopy on a scale from "-" to "+ + +".. The rates of positive expression of VEGF were 69.4% in BPH and 80.9% in PCa, positive staining mostly in the cytoplasm of glandular epithelia and cancer cells, and strongly positive in all the stroma vascular endothelial cells. The staining intensity of VEGF was significantly higher in the PCa than in the BPH group (P < 0.05) , in the bone metastasis (BM) than in the non-BM group (P < 0.01), and in the lowly than in the highly and moderately differentiated PCa tissues (P < 0.01). The expression of VEGF was positively correlated with that of ET-1 ( r(s) = 0.780, P < 0.01).. VEGF is involved in the development, progression and metastasis of PCa. VEGF and ET-1 may play a joint role in its development and progression.

Topics: Aged; Aged, 80 and over; Endothelin-1; Humans; Male; Middle Aged; Neoplasm Metastasis; Neoplasm Staging; Prostatic Hyperplasia; Prostatic Neoplasms; Vascular Endothelial Growth Factor Receptor-1

To investigate the effects of the epidermal growth factor on the mRNA expression of endothelin-1 and its receptors (ET(A)R, ET(B)R) in hormone refractory prostate cancer (HRPC) PC-3 cell lines.. PC-3 cells were cultured in vitro. After the treatment with EGF, the mRNA expressions of endothelin-1, ET(A)R and ET(B)R were detected by RT-PCR in PC-3 cell lines. The levels of the mRNA expression of endothelin-1 and its receptors were examined at different time points by RT-PCR.. The expressions of endothelin-1 and ET(A)R mRNA but not the mRNA expression of ET(B)R was observed in PC-3 cell lines. After 24 hours of treatment with EGF, the expressions of endothelin-1 and ET(A)R in PC-3 cell lines were both up-regulated and there was significant difference (P < 0.05) between the experimental and control groups. Different expression levels of endothelin-1 and ET(A)R mRNA were noted at different time points of EGF intervention, up-regulated with the increase of treatment time, and with significant difference (P < 0.05).. EGF can up-regulate the mRNA expressions of endothelin-1 and ET(A)R in PC-3 cell lines and play a great role in prostate cancer progression, which may offer a substructure of molecular biology for the treatment of HRPC.

Topics: Cell Line, Tumor; Endothelin-1; Epidermal Growth Factor; Gene Expression Regulation, Neoplastic; Humans; Male; Prostatic Neoplasms; Receptor, Endothelin A; Receptor, Endothelin B; Receptors, Endothelin; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger

Following androgen ablation therapy, the majority of prostate cancer patients develop treatment resistance with a median time of 18-24 months to disease progression.. To identify molecular targets that promote prostate cancer cell survival and contribute to androgen independence, we evaluated changes in LNCaP cell gene expression during 12 months of androgen deprivation. At time points reflecting critical growth and phenotypic changes, we performed Affymetrix expression array analysis to examine the effects of androgen deprivation during the acute response, during the period of apparent quiescence, and following the emergence of a highly proliferative, androgen-independent prostate cancer cell phenotype (LNCaP-AI).. We discovered alterations in gene expression for molecules associated with promoting prostate cancer cell growth and survival, and regulating cell cycle progression and apoptosis. Additionally, expression of AR co-regulators, adrenal androgen metabolizing enzymes, and markers of neuroendocrine disease were significantly altered.. These findings contribute greatly to our understanding of androgen-independent prostate cancer. The value of this longitudinal approach lies in the ability to examine gene expression changes throughout the adaptive response to androgen deprivation; it provides a more dynamic illustration of genes which contribute to disease progression in addition to specific genes which constitute an androgen-independent phenotype.

Topics: Androgen Antagonists; Androgens; Antineoplastic Agents, Hormonal; Apoptosis; Cell Cycle; Cell Line, Tumor; Cell Survival; Drug Resistance, Neoplasm; Endothelin-1; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Humans; Male; Prostatic Neoplasms; Receptor, Endothelin A; Receptors, Androgen

To analyze the expression of endothelin-1 (ET-1), endothelin-A receptor (ET-A-R), and endothelin-B receptor (ET-B-R) in incidental prostate cancer in cystoprostatectomies (CyPs), clinically detected hormonally untreated and hormonally treated prostate cancer in radical prostatectomies (RPs), and hormone-independent prostate cancer in transurethral resections of the prostate (TURPs). High-grade prostatic intraepithelial neoplasia (HGPIN) was also investigated.. Nineteen CyPs and 44 RPs (25 untreated, 19 treated) with pT2a Gleason score 6 cancer and HGPIN were examined. The study included 9 TURPs with hormone-independent cancer and 8 normal cases from CyPs without prostate cancer and HGPIN. ET-1, ET-A-R, ET-B-R, and the proliferation marker Ki67 were investigated immunohistochemically.. The mean proportion of prostate cancer cells with strong ET-1, ET-A-R, and ET-B-R expression in CyPs was lower (18.5%, 28.0%, and 14.7%, respectively) than in the untreated group (40.7%, 39.7%, and 25.1%) and higher than in treated group (5.0%, 13.9%, and 11.3%). The highest values were in the hormone-independent cancer group (53.9%, 48.9%, 33.3%). The trend in the proportion of HGPIN cells overexpressing ET-1, ET-A-R, and ET-B-R was similar to that in the cancer groups. The values in HGPIN lesions were always slightly greater than those in the cancers. Ki67 expression in HGPIN and prostate cancer in CyPs was lower than in RPs and TURPs.. Our study showed for the first time that ET-1, ET-A-R, and ET-B-R expression is not limited to the late prostate cancer phases. It is also seen in HGPIN as well as in prostate cancers considered to be clinically insignificant, such as those seen in CyP specimens. Although the series of cases in each group was small, our data may have clinical significance.

Topics: Adult; Aged; Aged, 80 and over; Endothelin-1; Humans; Immunohistochemistry; Ki-67 Antigen; Male; Middle Aged; Prostatic Intraepithelial Neoplasia; Prostatic Neoplasms; Receptor, Endothelin A; Receptor, Endothelin B

Topics: Endothelin-1; Humans; Male; Prostatic Intraepithelial Neoplasia; Prostatic Neoplasms; Receptor, Endothelin A; Receptor, Endothelin B

Emerging evidence supports a role for endothelin-1 (ET-1), endothelin A and B receptors (ET(A) and ET(B), respectively), and neutral endopeptidase (NEP) in the progression of prostate carcinoma. In clinical trials for advanced prostate cancer, ET axis blockade significantly delayed the time to disease progression in a subset of patients. We examined ET axis expression in prostate cancer, prostatic intraepithelial neoplasia, and normal adjacent tissue and then analyzed the relationship of the protein levels with disease progression.. The expression levels of ET(A), ET(B), and NEP were determined in 120 prostate cancer specimens obtained at surgery or biopsy by immunohistochemistry. In situ hybridization on a subset of the specimens was used to confirm the immunohistochemistry findings.. In regions of adenocarcinoma, immunohistochemistry analysis demonstrated high ET(A) expression in 72% of the specimens. ET(A) expression was significantly elevated with increased pathologic stage and grade. ET(B) and NEP levels were significantly decreased in adenocarcinoma compared with normal adjacent tissue and prostatic intraepithelial neoplasia; however, reduced expression did not correlate with tumor grade or stage. Patients with prostate-specific antigen recurrence had significantly greater ET(A) levels in their primary tumors than did patients who were disease free 5 years after prostatectomy. Patients with high ET(A) expression in the adenocarcinoma regions with low ET(B) and NEP had a significantly decreased interval to prostate-specific antigen progression compared with patients with low ET(A) or high ET(B)/NEP expression.. These data suggest two patterns of ET(A) expression in primary prostate cancer, with increased expression correlating with more advanced disease. The use of these expression patterns to identify patients more likely to respond to ET axis blockade might enhance treatment outcomes.

Topics: Aged; Aged, 80 and over; Endothelin-1; Humans; Male; Middle Aged; Neoplasm Recurrence, Local; Prostatic Intraepithelial Neoplasia; Prostatic Neoplasms; Receptor, Endothelin A; Receptor, Endothelin B

To investigate the different expressions of endothelin-1 ET-1) in prostate cancer (PCa) and benign prostatic hyperplasia (BPH) tissues and their clinical significance.. A total of 36 BPH and 44 PCa specimens were examined for the expression of ET-1 by immunohistochemical technique (Elivision plus method). The staining intensity for ET-1 was assessed by light microscopy on a scale from "-" to "+ + +".. Positive immunoreactivity was found in BPH and PCa, with a positive rate of 100%. Positive staining was located mostly in the cytoplasm of glandular epithelia and smooth muscle cells of both BPH and PCa and was noted in all stroma vascular endothelial cells. These were no significant differences in the intensity of positive staining for ET-1 between the groups of BPH and PCa (P > 0.05), bone metastasis (BM) and non-BM (P > 0.05), and highly and moderately differentiated PCa (P > 0.05), but the staining intensity for ET-1 was significantly higher in the poorly than in the highly and moderately differentiated PCa (P < 0.01).. ET-1 has a high expression and the localization is the same in both BPH and PCa. It is involved in the development and progression of BPH and PCa.

Topics: Aged; Aged, 80 and over; Endothelin-1; Humans; Immunohistochemistry; Lymphatic Metastasis; Male; Middle Aged; Prostate; Prostatic Hyperplasia; Prostatic Neoplasms

Both malignant and normal prostate epithelial cells produce endothelin-1 (ET-1), a critical factor in prostate cancer (CaP) progression. beta-Catenin (beta-cat), a key component of the Wnt signaling pathway, is also implicated in CaP progression via beta-cat/T cell factor (Tcf) signaling. We recently demonstrated that beta-cat/Tcf-4 regulates transcription of ET-1 in colon cancer cells. In the present study, we found that Tcf-4 specifically bound to and activated the ET-1 promoter in vivo in human CaP cells and mouse prostate tissue. Expression of ET-1 in DU145 CaP cells was down-regulated by knocking down endogenous beta-cat or Tcf-4. Ectopic activation of beta-cat/Tcf-4 signaling significantly elevated expression of ET-1 in LNCaP cells. In addition, genetic ablation of beta-cat significantly inhibited transcription of ET-1 in primary prostate epithelial cells. Meanwhile, exogenous ET-1 enhanced beta-cat/Tcf signaling and ET-1 expression in DU145 cells, which was blocked by both selective phosphatidylinositol 3-kinase (PI3K) inhibitor 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one (LY294002) and endothelin-A receptor antagonist cyclo(L-Leu-D-Trp-D-Asp-L-Pro-D-Val) (BQ123). Furthermore, knockdown of either beta-cat or Tcf-4 substantially reduced cell proliferation and potentiated paclitaxel-induced apoptosis in DU145 cells, which largely were rescued by treatment with exogenous ET-1. Together, our results suggest that beta-cat/Tcf-4 signaling transcriptionally activates ET-1 in CaP cells; meanwhile, ET-1 enhances beta-cat/Tcf-4 signaling and in turn further increases ET-1 expression in a PI3K-dependent manner. The positive inter-regulation between beta-cat/Tcf-4 signaling and ET-1 signaling potentiates proliferation and survival of CaP cells, thereby representing a novel mechanism that contributes to CaP progression.

Topics: Animals; Antineoplastic Agents, Phytogenic; Apoptosis; beta Catenin; Cell Proliferation; Endothelin A Receptor Antagonists; Endothelin-1; Gene Expression Regulation, Neoplastic; Humans; Male; Mice; Paclitaxel; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Promoter Regions, Genetic; Prostatic Neoplasms; Signal Transduction; TCF Transcription Factors; Thymidine; Transcription Factor 7-Like 2 Protein; Transcription, Genetic; Tumor Cells, Cultured

We have previously reported that adenoviral vector-mediated interferon (IFN)-beta gene therapy inhibits orthotopic growth of human prostate cancer cells in nude mice. The purpose of this study was to determine efficacy and mechanisms of this therapy in immune-competent mice. TRAMP-C2Re3 mouse prostate cancer cells infected with 100 multiplicity of infection (MOI) of adenoviral vector encoding for mouse IFN-beta (AdmIFN-beta), but not AdE/1 (a control adenoviral vector), produced approximately 60 ng/10(5) cells/24 h of IFN-beta. The tumorigenicity of AdmIFN-beta-transduced cells was dramatically reduced in the prostates of C57BL/6 mice. A single intratumoral injection of 2 x 10(9) PFU (plaque-forming unit) of AdmIFN-beta inhibited tumor growth by 70% and prolonged survival of tumor-bearing mice. Intriguingly, this AdmIFN-beta therapy did not alter the growth of tumors in inducible nitric oxide synthase (iNOS)-null C57BL/6 mice. Immunohistochemical analysis revealed that treatment of tumors with AdmIFN-beta in wild-type C57BL/6 mice led to increased iNOS expression, decreased microvessel density, decreased cell proliferation, and increased apoptosis. Furthermore, quantitative reverse-transcriptional PCR analysis showed that AdmIFN-beta therapy, in C57BL/6 but not the iNOS-null counterparts, reduced levels of the mRNAs for angiopoietin, basic fibroblast growth factor, matrix metalloproteinase-9, transforming growth factor-beta1, vascular endothelial growth factor (VEGF)-A, and VEGF-B, as well as the antiapoptotic molecule endothelin-1. These data indicated that IFN-beta gene therapy could be effective alternative for the treatment of locally advanced prostate cancer and suggest an obligatory role of NO in IFN-beta antitumoral effects in vivo.

Topics: Adenoviridae; Animals; Cytokines; Endothelin-1; Gene Expression Regulation, Neoplastic; Genetic Therapy; Interferon-beta; Male; Matrix Metalloproteinase 9; Mice; Mice, Mutant Strains; Neoplasms, Experimental; Nitric Oxide Synthase Type II; Prostatic Neoplasms; Transduction, Genetic

The endothelins (ETs), which include ET-1, ET-2, ET-3, and their receptors ET-A and ET-B, play a major role in tumor growth, proliferation, apoptosis, angiogenesis, and bone metastasis. Atrasentan is a novel and selective inhibitor of ET-1 and ET-A. In vitro and in vivo data show that this oral agent is capable of inhibiting tumor cells in vitro. More recently, this agent was studied in several phase I trials with refractory carcinoma patients. Subsequently, phase II and III clinical trials evaluating atrasentan in patients with hormone-refractory prostate carcinoma have suggested that targeting this pathway may be a new therapeutic strategy in the treatment of solid malignancies, specifically, prostate cancer.

Topics: Antineoplastic Agents; Atrasentan; Clinical Trials as Topic; Disease Progression; Endothelin A Receptor Antagonists; Endothelin Receptor Antagonists; Endothelin-1; Endothelins; Humans; Male; Neoplasms; Prostatic Neoplasms; Pyrrolidines; Receptor, Endothelin A; Receptors, Endothelin

The neuropeptides bombesin and endothelin-1 stimulate prostate cancer (PC) cell migration and invasion (J Clin Invest, 2000; 106: 1399-1407). The intracellular signaling pathways that direct this cell movement are not well delineated. The monomeric GTPase RhoA is required for migration in several cell types including neutrophils, monocytes and fibroblasts. We demonstrate that bombesin-stimulated PC cell migration occurs via the heterotrimeric G-protein-coupled receptors (G-protein) G alpha 13 subunit leading to activation of RhoA, and Rho-associated coiled-coil forming protein kinase (ROCK). Using siRNA to suppress expression of the three known G-protein alpha-subunit-associated RhoA guanine nucleotide exchange factors (GEFs), we also show that two of these RhoA GEFs, PDZ-RhoGEF and leukemia-associated RhoGEF (LARG), link bombesin receptors to RhoA in a non-redundant manner in PC cells. We next show that focal adhesion kinase, which activates PDZ-RhoGEF and LARG, is required for bombesin-stimulated RhoA activation. Neutral endopeptidase (NEP) is expressed on normal prostate epithelium whereas loss of NEP expression contributes to PC progression. We also demonstrate that NEP inhibits neuropeptide activation of RhoA. Together, these results establish a contiguous signaling pathway from the bombesin receptor to ROCK in PC cells, and they implicate NEP as a major regulator of neuropeptide-stimulated RhoA in these cells. This work also identifies members of this signaling pathway as potential targets for rational pharmacologic manipulation of neuropeptide-stimulated migration of PC cells.

Topics: Bombesin; Cell Line, Tumor; Cell Movement; Cytoskeleton; Endothelin-1; Enzyme Activation; Humans; Male; Neprilysin; Neuropeptides; Prostatic Neoplasms; rhoA GTP-Binding Protein; Signal Transduction

To investigate plasma endothelin-1 (ET-1) level in patients with prostate cancers and its clinical significance.. Plasma ET-1 level was measured by radioimmunoassay in 31 patients of prostate cancer (23 with non-HRPC, 8 with HRPC) and 26 patients of BPH.. Compared with each other of the ET-1 level, there were no significant difference among the BPH group,non-HRPC group and HRPC group. No significant difference was found either between bone metastasis (BM) and non- BM, between high and middling differentiation prostate cancer group, as well as in different PSA level groups (P >0.05). But the ET-1 level in low differentiation prostate cancer was notably lower than those of the high and middle respectively (P < 0.05).. To detect plasma endothelin-1 (ET-1) level is not a useful method to evaluate the development and the prognosis of prostate cancer.

Topics: Aged; Aged, 80 and over; Endothelin-1; Humans; Male; Prognosis; Prostatic Hyperplasia; Prostatic Neoplasms; Radioimmunoassay

Mitogenic and anti-apoptotic actions of endothelin-1 (ET-1) are mediated through endothelin A (ET(A)) receptors. We investigated endothelin receptor expression in increasingly aggressive phenotype and in vivo effects of combination therapy using ET(A) antagonist with paclitaxel.. Dunning prostate cancer cells ranged in aggressiveness from non-tumorigenic G, to tumorigenic, non-metastatic AT-1, and to tumorigenic and metastatic MLL. Binding assays were performed alongside Q-PCR to assess receptor density. MLL xenografts were treated with vehicle, atrasentan, paclitaxel, and paclitaxel+atrasentan.. Saturation binding assays demonstrated endothelin receptor density of MLL and AT-1 cells seven- and threefold higher than G cells, respectively. Q-PCR showed 9- and 4.5-fold greater ET(A) mRNA expression in MLL and AT-1 than G cells, respectively and no endothelin receptor B (ET(B)) expression. Combination therapy had significant effect on reduction of tumor volume than paclitaxel or atrasentan alone.. ET(A) expression increases in aggressive prostate carcinoma. ET(A) blockade combined with paclitaxel may reduce tumor growth in advanced prostate carcinoma.

Topics: Adenocarcinoma; Animals; Disease Progression; Endothelin A Receptor Antagonists; Endothelin-1; Humans; Male; Mice; Phenotype; Prostatic Neoplasms; Receptor, Endothelin A; Receptor, Endothelin B

Endothelin-1 (ET-1), produced by the prostate epithelia, likely plays an important role in the progression of prostate cancer. ET-1 can bind two receptor subtypes; generally, binding of the endothelin receptor A (ET(A)) induces a survival pathway, whereas binding of the endothelin receptor B (ET(B)) mediates clearance of circulating ET-1 as well as promotes apoptosis. In prostate carcinoma, hypermethylation of the ET(B) promoter results in repression of ET(B) expression, thereby eliminating the negative growth response that ET-1 binding elicits through this receptor. Therefore, activation of ET(A) exclusively provides a pathway for survival advantage. Our current studies examine the mechanisms by which activation of the ET(A) may allow growth/survival. ET-1 treatment of prostate tumor cells significantly decreased paclitaxel-induced apoptosis through activation of the ET(A) subtype. The anti-apoptotic effects of ET-1 are mediated, at least in part, through the Bcl-2 family. Although no significant changes in Bcl-2 expression occurred with ET-1 treatment, the pro-apoptotic family members Bad, Bax, and Bak all decreased significantly. Further analysis of the survival pathway demonstrated that phosphorylation of Akt occurs with ET-1 treatment in a time- and dose-dependent manner through phosphatidyinositol 3-kinase activation. These data support the combination of ET(A) antagonists and apoptosis-inducing therapies for prostate cancer treatment.

Topics: Annexin A5; Apoptosis; bcl-2 Homologous Antagonist-Killer Protein; bcl-2-Associated X Protein; bcl-Associated Death Protein; Carrier Proteins; Cell Line, Tumor; Cell Survival; DNA Methylation; Dose-Response Relationship, Drug; Endothelin-1; Flow Cytometry; Humans; Immunoblotting; Male; Membrane Proteins; Paclitaxel; Phosphatidylinositol 3-Kinases; Phosphorylation; Promoter Regions, Genetic; Prostatic Neoplasms; Protein Binding; Proto-Oncogene Proteins c-bcl-2; Receptors, Endothelin

Prostate cancer frequently metastasizes to bone where it forms osteoblastic lesions through unknown mechanisms. Bone morphogenetic proteins (BMP) are mediators of skeletal formation. Prostate cancer produces a variety of BMPs, including BMP-6. We tested the hypothesis that BMP-6 contributes to prostate cancer-induced osteosclerosis at bone metastatic sites. Prostate cancer cells and clinical tissues produced BMP-6 that increased with aggressiveness of the tumor. Prostate cancer-conditioned medium induced SMAD phosphorylation in the preosteoblast MC3T3 cells, and phosphorylation was diminished by anti-BMP-6 antibody. Prostate cancer-conditioned medium induced mineralization of MC3T3 cells, which was blocked by both the BMP inhibitor noggin and anti-BMP-6. Human fetal bones were implanted in severe combined immunodeficient mice and after 4 weeks, LuCaP 23.1 prostate cancer cells were injected both s.c. and into the bone implants. Anti-BMP-6 or isotype antibody administration was then initiated. Anti-BMP-6 reduced LuCaP 23.1-induced osteoblastic activity, but had no effect on its osteolytic activity. This was associated with increased osteoblast numbers and osteoblast activity based on bone histomorphometric evaluation. As endothelin-1 has been implicated in bone metastases, we measured serum endothelin-1 levels but found they were not different among the treatment groups. In addition to decreased bone production, anti-BMP-6 reduced intraosseous, but not s.c., tumor size. We found that BMP-2, BMP-4, BMP-6, and BMP-7 had no direct effect on prostate cancer cell growth, but BMP-2 and BMP-6 increased the in vitro invasive ability of prostate cancer cell. These data show that prostate cancer promotes osteoblastic activity through BMP-6 and that, in addition to its bone effects, suggest that BMPs promote the ability of the prostate cancer cells to invade the bone microenvironment.

Topics: Animals; Bone Development; Bone Morphogenetic Protein 6; Bone Morphogenetic Proteins; Bone Neoplasms; Cell Line, Tumor; Culture Media, Conditioned; Endothelin-1; Humans; Male; Mice; Mice, SCID; Osteoblasts; Phosphorylation; Prostatic Neoplasms; Smad Proteins

(1) Atrasentan (Xinlay(R)) is an anti-cancer drug from a new class of agents called selective endothelin-A receptor antagonists. The orally administered drug is being studied in a subset of patients with advanced prostate cancer. (2) Phase II and III studies evaluating time to clinical and radiographic progression failed to demonstrate a significant benefit with atrasentan versus placebo. (3) The adverse effects, observed more frequently in those treated with atrasentan than in placebo-treated patients, were peripheral edema, rhinitis, headache, infection, dyspnea, and heart failure. (4) Atrasentan's role in the various stages of advanced prostate cancer, and relative to the chemotherapeutic agent docetaxel, has not been determined.

Topics: Bone Neoplasms; Canada; Clinical Trials, Phase II as Topic; Clinical Trials, Phase III as Topic; Drug Approval; Endothelin Receptor Antagonists; Endothelin-1; Humans; Male; Neoplasm Metastasis; Prostatic Neoplasms; Pyrrolidines; Randomized Controlled Trials as Topic; Survival Rate; Treatment Outcome; United States; United States Food and Drug Administration

Some men treated with atrasentan (ABT-627), an endothelin A (ETA) receptor inhibitor, had declines in their serum PSA levels. It is our hypothesis that this decrease is due to anti-tumoral activity and not a reduction in PSA secretion at the cellular level.. Two PSA secreting prostate cancer cell lines (LAPC4 and LNCaP) were treated with atrasentan and an ETB receptor antagonist (A192621) in varying concentrations (10(-6)-10(-10) M) and PSA levels were measured in the culture media.. LNCaP and LAPC4 cells both express ETA receptors. Neither the ETA or ETB antagonist altered PSA secretion, while addition of DHT, a positive control, produced a marked increase in PSA secretion.. Blockade of the ETA receptor does not affect the secretion of PSA in prostate cancer cell lines.

Topics: Atrasentan; Endothelin A Receptor Antagonists; Endothelin-1; Humans; Male; Prostate-Specific Antigen; Prostatic Neoplasms; Pyrrolidines; Receptor, Endothelin A; Tumor Cells, Cultured

In some diseases in which endothelin-1 production increases, e.g. prostate cancer, endothelin-1 is considered to be involved in the generation of pain. In the present study, we investigated the effects of a selective endothelin ET(A) receptor antagonist, (E)-N-[6-methoxy-5-(2-methoxyphenoxy)[2,2'-bipyrimidin]-4-yl]-2-phenylethenesulfonamide monopotassium salt (YM598), on the nociception potentiated by endothelin-1 in a cancer inoculation-induced pain model in mice, induced by inoculation of the androgen-independent human prostate cancer cell line PPC-1 into the hind paws of severe combined immunodeficiency (SCID) mice. No pain responses were observed in the sham-operated mice, whereas monophasic pain responses were observed in the PPC-1-inoculated mice. Endothelin-1 (1 to 10 pmol/paw) but not sarafotoxin S6c potentiated the pain response in prostate cancer-inoculated mice. Both YM598 and atrasentan (0.3 to 3 mg/kg, p.o.) significantly inhibited the endothelin-1 (10 pmol/paw)-induced potentiation of nociception in a dose-dependent manner. These results suggest that selective endothelin ET(A) receptor antagonists might relieve pain in patients with various diseases in which endothelin-1 production is increased, e.g. prostate cancer.

Topics: Analgesics, Non-Narcotic; Animals; Atrasentan; Dose-Response Relationship, Drug; Endothelin A Receptor Antagonists; Endothelin-1; Hindlimb; Male; Mice; Mice, SCID; Pain; Prostatic Neoplasms; Pyrimidines; Pyrrolidines; Sulfonamides; Time Factors; Viper Venoms

To study the expression of ET receptor and the apoptosis after intervened with ET receptor antagonist in androgen-independent prostate cancer.. PC3, an androgen-independent prostate cancer cell line, was used. The expression of ETA and ETB receptor in PC3 was measured through RT-PCR. After intervened with selective ETA and ETB receptor antagonist, the apoptosis in PC3 was studied through flow cytometry and electron microscope.. Clear signal was obtained in PC3 for ETA receptor mRNA transcript, while the signal for ETB receptor mRNA transcript was very weak. The expression of ETA receptor mRNA was obviously reduced and the apoptosis of PC3 cell was observed after intervened with selective ETA receptor antagonist. There was no change after intervened with selective ETB receptor antagonist.. ET-1 exerts its effects through the ETA receptor subtype and ETB receptor is silenced in PC3. The expression of ETA was reduced and the apoptosis was observed in PC3 when ETA receptor was blocked. It was dose-dependent.

Topics: Androgens; Apoptosis; Endothelin A Receptor Antagonists; Endothelin B Receptor Antagonists; Endothelin-1; Humans; In Vitro Techniques; Male; Neoplasms, Hormone-Dependent; Oligopeptides; Peptides, Cyclic; Piperidines; Prostatic Neoplasms; Receptor, Endothelin A; Receptor, Endothelin B

In some diseases in which endothelin-1 (ET-1) production increases (e.g. prostate cancer), ET-1 is considered to be involved in the generation of pain. In the present study, we investigated the effects of a selective endothelin-A receptor antagonist, YM598, on the nociception potentiated by ET-1 in formalin-induced and cancer inoculation-induced pain models in mice. The formalin-induced pain model was prepared by intraplantar injection of 0.7% formalin into the hind paws of ICR mice, and the cancer pain model was prepared by inoculation of the human prostate cancer cell line PPC-1 into the hind paws of severe combined immunodeficiency mice. Formalin caused a biphasic pain response and paw edema in the mouse hind paw. ET-1 (10 pmol/paw) potentiated these responses, and single oral administration of YM598 (0.3-3 mg/kg) significantly inhibited this ET-1-induced potentiation of nociception and paw edema. ET-1 (10 pmol/paw) also potentiated the pain response in prostate cancer-inoculated mice. Both YM598 and atrasentan (0.3-3 mg/kg) significantly inhibited the ET-1-induced potentiation of nociception. These results suggest that selective endothelin-A receptor antagonists relieve pain in patients with various diseases in which ET-1 production increases (e.g. prostate cancer).

Topics: Administration, Oral; Analgesics, Non-Narcotic; Animals; Behavior, Animal; Cell Line, Tumor; Disease Models, Animal; Dose-Response Relationship, Drug; Endothelin A Receptor Antagonists; Endothelin-1; Formaldehyde; Humans; Male; Mice; Mice, Inbred ICR; Mice, SCID; Pain; Pain Measurement; Prostatic Neoplasms; Pyrimidines; Receptor, Endothelin A; Sulfonamides; Time Factors

Topics: Angiogenesis Inhibitors; Antineoplastic Agents; Atrasentan; Clinical Trials as Topic; Endothelin Receptor Antagonists; Endothelin-1; Humans; Male; Prostatic Neoplasms; Pyrrolidines

Endothelin (ET) plays a pivotal role in the pathogenesis of cell growth disorders such as cancer. Atrasentan (ABT-627), a selective antagonist for the ET receptor A (ET(A)), has shown benefit in controlling disease progression in men with hormone refractory prostate cancer who have undergone aggressive hormone ablation therapy. It is not known how hormone ablation affects ET-binding sites, although ET-1 and ET(A) expression are found to be elevated in prostate cancer patients. In this study, we examined the effect of castration on ET receptor binding in male beagle dogs. Three dogs were surgically castrated and another three sham-operated. The animals were sacrificed 1 week after operation and membranes were prepared from the prostate, heart, brain, kidney, liver and lung for ET-1, ET-3 and angiotensin II (A-II, as a control) binding studies. No significant difference in A-II binding was observed between castrated and sham-operated animals. However, ET-1 and ET-3 binding to prostate and brain membranes were altered significantly. From saturation binding studies using ET-1 in the prostate, the K(d) and B(max) values increased from 0.043 nM and 0.094 pmol/mg respectively in sham-operated dogs to 0.104 nM and 0.311 pmol/mg respectively in castrated animals. These results indicate that surgical castration in dogs produces a change in the ET receptor density in the prostate and brain, and may have implications for the effect of hormone ablation therapy on ET receptor expression in prostate cancer patients.

Topics: Angiotensin II; Animals; Brain; Dogs; Endothelin-1; Endothelin-3; Endothelins; Male; Orchiectomy; Prostate; Prostatic Neoplasms; Protein Binding; Receptors, Endothelin

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

Topics: Antineoplastic Agents; Atrasentan; Clinical Trials as Topic; Disease Progression; Endothelin-1; Humans; Male; Prostatic Neoplasms; Pyrrolidines

To study effects of estrogens on endothelin-1 (ET-1) mRNA expression in the androgen-sensitive LNCaP-FGC cell line and its androgen-resistant derivative LNCaP-r. Further, if effects of estrone sulfate (E1S) are mediated via conversion to estradiol-17beta (E2). Estrogens have been shown to down-regulate ET-1, a mediator of the osteoblastic response of bone to metastatic prostate cancer.. Cells were grown in steroid-depleted medium and incubated for 2-4 and 48 hours with 0, 1, 10, and 100 nM of either E1S or E2. mRNA levels were measured with an RT-PCR technique. Estrogen metabolism by LNCaP-FGC cells was studied by incubation with estrone (E1) and E1S at the same conditions, followed by determination of E1 and E2.. ET-1 mRNA expression in LNCaP-FGC cells was significantly suppressed by E2 and E1S following incubation for 2-4h but after 48 h only by E2 at 1 and 10nM and in LNCaP-r cells only by E2 at 100 nM following 2-4h of incubation. ET-1 mRNA expression was significantly higher in untreated LNCaP-r than in untreated LNCaP-FGC cells. E1 was efficiently transformed into E2 by LNCaP-FGC cells but very little to E1 and no E2 was formed from E1S.. ET-1 mRNA expression in LNCaP-FGC can be inhibited by E2, but also by its prehormone E1S. The lack of formation of E2 from E1S suggests a mode of action not related to classical steroid receptors. The higher level of ET-1 mRNA expression found in LNCaP-r cells may reflect the capability of a hormone refractory tumor to maintain activity on its own, independently of known regulatory mechanisms such as sex steroids.

Topics: Biomarkers, Tumor; Endothelin-1; Estradiol; Estrogen Receptor beta; Estrone; Gene Expression; Humans; Male; Neoplasms, Hormone-Dependent; Prostatic Neoplasms; Receptors, Estrogen; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Tumor Cells, Cultured

G-protein coupled receptor (GPCR) agonists such as neuropeptides activate the insulin-like growth factor-1 receptor (IGF-IR) or the serine-threonine protein kinase Akt, suggesting that neuropeptides-GPCR signaling can cross-communicate with IGF-IR-Akt signaling pathways. Neutral endopeptidase 24.11 (NEP) is a cell-surface peptidase that cleaves and inactivates the neuropeptides endothelin-1 (ET-1) and bombesin, which are implicated in progression to androgen-independent prostate cancer (PC). We investigated the mechanisms of NEP regulation of neuropeptide-mediated cell survival in PC cells, including whether neuropeptide substrates of NEP induce phosphorylations of IGF-IR and Akt in PC cells. Western analyses revealed ET-1 and bombesin treatment induced phosphorylation of IGF-IRbeta and Akt independent of IGF-I in TSU-Pr1, DU145, and PC-3 PC cells, which lack NEP expression, but not in NEP-expressing LNCaP cells. Recombinant NEP and induced NEP expression in TSU-Pr1 cells using a tetracycline-repressive expression system inhibited ET-1-mediated phosphorylation of IGF-IRbeta and Akt, and blocked the protective effects of ET-1 against apoptosis induced by serum starvation. Incubation of TSU-Pr1 cells with specific kinase inhibitors together with ET-1 or bombesin showed that IGF-IR activation is required for neuropeptide-induced Akt phosphorylation, and that neuropeptide-induced Akt activation is predominantly mediated by Src and phosphatidylinositol 3-kinase but not by mitogen-activated protein kinase or protein kinase C. These data show that the neuropeptides ET-1 and bombesin stimulate ligand-independent activation of the IGF-IR, which results in Akt activation, and that this cross-communication between GPCR and IGF-IR signaling is inhibited by NEP.

Topics: Bombesin; Cell Survival; Endothelin-1; Enzyme Activation; Humans; Male; Neprilysin; Phosphorylation; Prostatic Neoplasms; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; Receptor, IGF Type 1; Signal Transduction; src-Family Kinases; Transcriptional Activation; Tumor Cells, Cultured

Various reports suggest a role for endothelin-1 in prostatic carcinoma. The objective of the current study was to evaluate the changes of the immunodetectable endothelin-1 in prostatic carcinomas characterized by different grades of regression due to total androgen withdrawal.. An immunohistochemical study was made on eleven prostatic carcinomas treated with neoadjuvant hormonal therapy for 3 months, followed by radical prostatectomy. Another ten specimens of untreated carcinomas were studied for comparison. An appraisal of androgen receptors was associated. A highly specific polyclonal antibody against endothelin-1 and a commercial monoclonal mouse antibody for androgenic receptors were used.. In all cases, a prevalent quantity of androgenic receptor-positive tumor cells were present. Neoplastic cells of untreated carcinomas showed a strong and heterogeneous staining for endothelin -1. In unregressed areas of treated cases, the features of endothelin-1 and androgen-receptor staining were the same as those of untreated cases. In areas characterized by moderate histologic regression, the endothelin-1 staining became more heterogeneous. In areas of strong histologic regression, a diffuse membrane staining was often noted. Only in completely regressed cancer cells was a definite loss of immunodetectable endothelin-1 and androgenic receptors observed.. Endothelin-1 is one of the proteins intrinsic to prostatic epithelial cells, both benign and malignant. In cases treated with androgen withdrawal, histologic regression is not uniform. In unmodified areas, immunodetectable endothelin-1 and androgenic receptors also are unmodified, thus suggesting some mechanism that substitutes for the action of androgen. Only neoplastic cells with complete histologic regression also lose androgenic receptors and endothelin-1, whereas the preserved immunostaining in deeply modified prostatic neoplastic cells seems to indicate that these cells still are potentially active.

Topics: Aged; Antineoplastic Agents, Hormonal; Cyproterone Acetate; Endothelin-1; Goserelin; Humans; Immunoenzyme Techniques; Leuprolide; Male; Middle Aged; Prostatectomy; Prostatic Neoplasms; Receptors, Androgen; Treatment Outcome

Topics: Antineoplastic Agents; Bone and Bones; Bone Neoplasms; Endothelin Receptor Antagonists; Endothelin-1; Humans; Male; Prostatic Neoplasms; Receptor, Endothelin A

Recent data demonstrate that endothelin-1 (ET-1) concentration increases in plasma of men with advanced, hormone-refractory prostate adenocarcinoma. In addition, ET-1 is involved in osteblastic remodelling and new bone formation, suggesting a role for this vasoactive peptide in the metastatic progression of prostate cancer to the bone.. We investigated the regulation of ET-1 expression in androgen-sensitive and insensitive prostate cancer cell lines by androgens and several factors involved in progression of prostate cancer (EGF) and bone remodelling (TGFbeta-1, IL1-alpha and IGF-1).. Northern analysis and radio immunoassay demonstrated that all the ET-1 pathways are tuned off in the androgen-sensitive LNCaP cell line when compared to the androgen-insensitive PC-3 and DU145. In PC-3 cells transfected with a full-length androgen receptor expression vector (PC-3-AR), treatment with androgens reduced gene expression and secretion of ET-1 without affecting the gene expression of ET-3. Collectively, these data support a role for androgens in the regulation of ET-1 production by prostate adenocarcinoma cells. In PC-3 and DU145 cells, ET-1 gene expression and secretion were up-regulated by TGFbeta-1, EGF and IL1-alpha, whereas IGF-1 was ineffective. Conversely, none of the treatments affected ECE-1 or ET-3 gene expression.. In conclusion, ET-1 production by prostate adenocarcinoma cells is down-regulated by androgens and up-regulated by factors involved in tumour progression indicating a role for this peptide in the biology of prostate cancer. In view of the role exerted by ET-1 in the process of bone metastasis, our data suggest the use of ET-1 receptor antagonists in the treatment of advanced prostate cancer.

Topics: Adenocarcinoma; Androgens; Blotting, Northern; Bone Neoplasms; Cytokines; Endothelin-1; Endothelin-3; Epidermal Growth Factor; Gene Expression Regulation, Neoplastic; Humans; Male; Metalloendopeptidases; Neoplasms, Hormone-Dependent; Prostatic Neoplasms; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; RNA, Neoplasm; Tumor Cells, Cultured

The causes for the propensity of metastasized prostate cancer cells to grow in bone and to induce osteoblastic lesions remain unresolved. Co-culture of human prostate cancer cell lines with bone slices was determined to increase the level of endothelin-1 (ET-1) mRNA and its production. ET-1 is an ejaculate protein that also stimulates osteoblasts. Osteoclastic bone resorption was significantly blocked by the presence of androgen-independent prostate cancer cells in a dose-dependent manner as that of synthetic ET-1. The inhibition could be neutralized by specific ET-1 antibody, indicating the association of prostate cancer-derived ET-1 with inhibition of bone resorption. The combined ET-1 activity on osteoclasts and osteoblasts disrupts bone remodelling. ET-1 production is also elevated in the presence of prostate-specific antigen (PSA). ET-1 in turn enhances DNA synthesis of prostate cancer cells. Interactions among cancer cells, bone, ET-1 and PSA may be critical in cancer growth and lesions in bone.

Topics: Analysis of Variance; Blotting, Northern; Bone and Bones; Bone Resorption; Cell Division; Endothelin-1; Humans; Male; Osteoblasts; Osteoclasts; Prostate-Specific Antigen; Prostatic Neoplasms; Reverse Transcriptase Polymerase Chain Reaction; Tumor Cells, Cultured

Phorbol esters induce apoptosis in androgen-sensitive LNCaP cells, which express neutral endopeptidase (NEP), but not in androgen-independent prostate cancer (PC) cells, which lack NEP expression. We investigated the role of NEP in PC cell susceptibility to 12-O-tetradecanoylphorbol-13-acetate (TPA). Western analysis showed that expression of NEP and protein kinase Cdelta (PKCdelta) correlated with PC cell sensitivity to TPA-induced growth arrest and apoptosis in LNCaP cells and in TSU-Prl cells expressing an inducible wild-type NEP protein. Inhibition of NEP enzyme activity using the specific NEP inhibitor CGS24592, or inhibition of PKCdelta using Rottlerin at concentrations that inhibit PKCdelta but not PKCalpha, significantly inhibited TPA-induced growth inhibition and cell death. Furthermore, pulse-chase experiments showed PKCdelta is stabilized in LNCaP cells and in TSU-Pr1 cells overexpressing wild-type NEP compared with PC cells lacking NEP expression. This results from NEP inactivation of its neuropeptide substrates (bombesin and endothelin-1), which in the absence of NEP stimulate cSrc kinase activity and induce rapid degradation of PKCdelta protein. These results indicate that expression of enzymatically active NEP by PC cells is necessary for TPA-induced apoptosis, and that NEP inhibits neuropeptide-induced, cSrc-mediated PKCdelta degradation.

Topics: Amino Acid Sequence; Apoptosis; Bombesin; Cell Division; CSK Tyrosine-Protein Kinase; Down-Regulation; Endothelin-1; Enzyme Activation; Growth Inhibitors; Humans; Isoenzymes; Male; Molecular Sequence Data; Neprilysin; Prostatic Neoplasms; Protein Kinase C; Protein Kinase C-delta; Protein-Tyrosine Kinases; src-Family Kinases; Tetradecanoylphorbol Acetate; Tumor Cells, Cultured

Increasing evidence indicates that endothelin 1 (ET-1) is implicated in prostate tumour progression. However, data on ET-1 regulation in human prostate and prostate cancer cell lines are lacking. In this study, regulation of ET-1 and its precursor big ET-1, using PC3 cells, a human bone metastatic prostatic carcinoma cell line, was addressed. ET-1 and big ET-1 assays demonstrated greater secretion of both peptides in the presence of 10% fetal calf serum (FCS) as compared with 0.5% FCS. Incubation of PC3 cells in the absence and presence of various cytokines and growth factors known to be implicated in prostate stroma-epithelium interactions, revealed that IL-6, FGF7/KGF and FGF2/bFGF had no effect on ET-1 and big ET-1 secretion, whereas interleukin 1beta (IL-1beta), tumour necrosis factor alpha (TNF-alpha) and transforming growth factor beta (TGF-beta) stimulated their secretion in a concentration-dependent manner. Binding experiments indicated the presence of specific ET-1 receptors in PC3 cells: Kdapp = 1.1 x 0.2 x 10(-10)M, Bmax = 2660 +/- 390 sites/cell. Data analysis demonstrated the presence of only the ETA receptor subtype in PC3 cells. In conclusion, our results indicate that the implication of ET-1 in prostate cancer is likely to be mediated via paracrine/autocrine control of cell factors.

Topics: Cytokines; Dose-Response Relationship, Drug; Endothelin-1; Endothelins; Growth Substances; Humans; Interleukin-1; Male; Prostatic Neoplasms; Protein Precursors; Receptors, Endothelin; Transforming Growth Factor beta; Tumor Cells, Cultured; Tumor Necrosis Factor-alpha; Up-Regulation

Endothelin-1 (ET-1) is not only a potent vasoconstrictor but also serves as an important growth stimulator in various cancers, including breast, cervical, pancreatic, and prostate cancer. This suggests that blockage of ET-1 production may suppress tumor growth and possibly metastasis. We observed that certain synthetic retinoids, and all-trans-retinoic acid can repress LNCaP prostate cancer cell growth in vitro. In addition, these retinoid compounds counteracted exogenous ET-1-induced growth stimulation. Retinoid-dependent growth retardation of LNCaP cells coincided with suppression of ET-1 gene expression to a level undetectable by reverse transcription-PCR. Contrarily, the androgen-insensitive DU145 cells were refractory to retinoid treatment. To investigate the underlying mechanisms of the cell-specific response to retinoids, we transfected ET-1 promoter constructs containing wild-type or mutated AP-1 or GATA-2 site into prostate cancer cells. Distinct regulations of ET-1 promoter activity were found; in LNCaP cells, both binding sites are essential for optimal promoter activation, whereas in DU145 cells, additional promoter sequences and/or transcriptional factors seem to be involved. Furthermore, several anti-AP-1 selective retinoids failed to repress ET-1 promoter activity and to exhibit a cell growth-inhibitory effect on LNCaP cells, suggesting that different retinoid structural configurations are required for the inhibition of an AP-1 complex versus an AP-1/GATA-2 complex.

Topics: DNA-Binding Proteins; Endothelin-1; GATA2 Transcription Factor; Humans; Male; Promoter Regions, Genetic; Prostatic Neoplasms; Retinoids; Transcription Factor AP-1; Transcription Factors; Transcription, Genetic; Tumor Cells, Cultured