adrenomedullin and Neoplasms

Adrenomedullin (AM) is a peptide responsible for many physiological processes including vascular health and hormone regulation. Dysregulation of AM signaling can stimulate cancers by promoting proliferation, angiogenesis and metastasis. Two AM receptors contribute to tumor progression in different ways. Adrenomedullin-1 receptor (AM. We review the literature to highlight AM's role in cancer as well as delineating the specific roles AM. As tool compounds, AM

Topics: Adrenomedullin; Antineoplastic Agents; Calcitonin Receptor-Like Protein; Humans; Neoplasms; Receptor Activity-Modifying Protein 2; Receptor Activity-Modifying Protein 3; Receptors, Adrenomedullin; Tumor Microenvironment

The peptide hormone adrenomedullin (ADM) consists of 52 amino acids and plays a pivotal role in the regulation of many physiological processes, particularly those of the cardiovascular and lymphatic system. Like calcitonin (CT), calcitonin gene-related peptide (CGRP), intermedin (IMD) and amylin (AMY), it belongs to the CT/CGRP family of peptide hormones, which despite their low little sequence identity share certain characteristic structural features as well as a complex multicomponent receptor system. ADM, IMD and CGRP exert their biological effects by activation of the calcitonin receptor-like receptor (CLR) as a complex with one of three receptor activity-modifying proteins (RAMP), which alter the ligand affinity. Selectivity within the receptor system is largely mediated by the amidated C-terminus of the peptide hormones, which bind to the extracellular domains of the receptors. This enables their N-terminus consisting of a disulfide-bonded ring structure and a helical segment to bind within the transmembrane region and to induce an active receptor confirmation. ADM is expressed in a variety of tissues in the human body and is fundamentally involved in multitude biological processes. Thus, it is of interest as a diagnostic marker and a promising candidate for therapeutic interventions. In order to fully exploit the potential of ADM, it is necessary to improve its pharmacological profile by increasing the metabolic stability and, ideally, creating receptor subtype-selective analogs. While several successful attempts to prolong the half-life of ADM were recently reported, improving or even retaining receptor selectivity remains challenging.

Topics: Adrenomedullin; Animals; Binding Sites; Calcitonin; Calcitonin Gene-Related Peptide; Calcitonin Receptor-Like Protein; Cardiovascular Diseases; Central Nervous System; Gene Expression Regulation; Humans; Islet Amyloid Polypeptide; Lymphatic System; Models, Molecular; Neoplasms; Peptide Hormones; Protein Binding; Signal Transduction

Sepsis and bloodstream infections remain a leading cause of death in immunocompromised patients with cancer. The management of these serious infections consist of empiric use of antimicrobial agents which are often overused. Procalcitonin and proadrenomedullin are biomarkers that have been extensively evaluated in the general populations but with little emphasis in the population immunocompromised patients with cancer, where they may have promising roles in the management of febrile patients. In this review, we summarize the available evidence of the potential role of these available biomarkers in guiding antimicrobial therapy to optimize the use of resources in the general patient population. Special emphasis is given to the role of these 2 biomarkers in the immunocompromised and critically ill patients with cancer, highlighting the distinctive utility of each.

Topics: Adrenomedullin; Bacteremia; Biomarkers; Critical Illness; Fever; Humans; Immunocompromised Host; Neoplasms; Procalcitonin; Protein Precursors; Randomized Controlled Trials as Topic; Sepsis

Adrenomedullin (AM), adrenomedullin 2 (AM2/intermedin) and calcitonin gene-related peptide (CGRP) are members of the calcitonin family of peptides. They can act as growth or survival factors for a number of tumours, including those that are endocrine-related. One mechanism through which this occurs is stimulating angiogenesis and lymphangiogenesis. AM is expressed by numerous tumour types and for some cancers, plasma AM levels can be correlated with the severity of the disease. In cancer models, lowering AM content or blocking AM receptors can reduce tumour mass. AM receptors are complexes formed between a seven transmembrane protein, calcitonin receptor-like receptor and one of the two accessory proteins, receptor activity-modifying proteins (RAMPs) 2 or 3 to give the AM1 and AM2 receptors respectively. AM also has affinity at the CGRP receptor, which uses RAMP1. Unfortunately, due to a lack of selective pharmacological tools or antibodies to distinguish AM and CGRP receptors, the precise receptors and signal transduction pathways used by the peptides are often uncertain. Two other membrane proteins, RDC1 and L1/G10D (the 'ADMR'), are not currently considered to be genuine CGRP or AM receptors. In order to properly evaluate whether AM or CGRP receptor inhibition has a role in cancer therapy, it is important to identify which receptors mediate the effects of these peptides. To effectively distinguish AM1 and AM2 receptors, selective receptor antagonists need to be developed. The development of specific CGRP receptor antagonists suggests that this is now feasible.

Topics: Adrenomedullin; Animals; Calcitonin Gene-Related Peptide; Humans; Neoplasms; Receptor Activity-Modifying Proteins; Receptors, Calcitonin Gene-Related Peptide

Tumor growth, invasion and metastasis are largely dependent on the development of tumor vasculature. A great number of pro- and antiangiogenic molecules, have been identified. Bone marrow-derived cells are mobilized and recruited to angiogenic sites, by a variety of growth factors and cytokines, to promote angiogenesis and the formation of new blood vessels. The hypoxic microenvironment that is inevitably generated in solid tumors is a major contributor to tumor angiogenesis. Tumor hypoxia aberrantly modulates the expression of many potent pro- and antiangiogenic molecules, primarily through the action of heterodimeric transcription factors termed hypoxia-inducible factors, HIF-1 and HIF-2. The disruption of the balance between pro- and antiangiogenic activities eventually leads to a shift in balance to a more angiogenic state. These findings have provoked considerable interest in HIFs as attractive targets for cancer therapy. Consequently, the development of small molecule HIF inhibitors is currently moving ahead at a fast pace.

Topics: Adrenomedullin; Angiogenesis Inhibitors; Angiopoietin-2; Animals; Bone Marrow Cells; Chemokines; Cyclooxygenase 2; Endothelins; Fibroblast Growth Factor 2; Humans; Hypoxia; Hypoxia-Inducible Factor 1; Intracellular Signaling Peptides and Proteins; Matrix Metalloproteinases; Membrane Proteins; Neoplasms; Neovascularization, Pathologic; NF-kappa B; Nitric Oxide Synthase; Placenta Growth Factor; Plasminogen Activator Inhibitor 1; Pregnancy Proteins; Proto-Oncogene Proteins c-sis; Stem Cell Factor; Vascular Endothelial Growth Factor A

Adrenomedullin (ADM) was first isolated from pheochromocytoma tissue as a novel vasodilative peptide in 1993. ADM binds to two receptors on plasma membrane which are comprised of Calcitonin Receptor-Like Receptor (CRLR), a member of serpentine receptor superfamily, and Receptor Activity Modifying Protein (RAMP) type 2 or 3. ADM is known to have hypotensive activity. Recently, ADM has been shown to be an almost ubiquitous peptide, synthesized in many mammalian tissues. ADM has potent in vivo angiogenic activity and tumor growth promoting effect in animal models. Many human tumors express ADM. However, only little information exists regarding the expression or the role of ADM in bone and its effect in bone metabolism. It is still not clear whether ADM is involved in pathogenesis and development of osteosarcoma, the most common form of bone tumor. The purpose of this review is to examine the most salient features of adrenomedullin biology, its expression in tumors and its potential implication in the treatment of bone tumors.

Topics: Adrenomedullin; Bone and Bones; Humans; Neoplasms

Hypoxia, a frequent characteristic in the microenvironment of solid tumors, leads to adrenomedullin (AM) upregulation through the hypoxia inducible factor-1 pathway, explaining its high expression in a variety of malignant tissues. AM is believed to play an important role in tumor progression and angiogenesis in many cancers. Therefore, it could become a new therapeutic target.. We performed a review of the literature based on published data to highlight AM's critical roles in tumor cell growth and cancer invasiveness, and its involvement in tumor angiogenesis through promotion of recruitment of hematopoietic progenitors, vascular morphogenesis, and blood vessel stabilization and maturation. Inhibition of AM has antitumoral effects linked to antiangiogenic effects but in some cases also to direct antiproliferative activity on cancer cells. Several studies demonstrated that systemic inhibition of AM receptors was well tolerated in murine models.. The goal of this review is to inform readers about the role of AM in tumor angiogenesis and cancer progression and, therefore, about its possible place as a new therapeutic target.. Taken together, these data support targeting the AM pathway as a new potential therapy in cancer, complementary to other existing treatments.

Topics: Adrenomedullin; Angiogenesis Inhibitors; Animals; Cell Differentiation; Cell Proliferation; Disease Progression; Humans; Hypoxia; Hypoxia-Inducible Factor 1; Mice; Molecular Targeted Therapy; Neoplasms; Neovascularization, Pathologic; Treatment Outcome; Vascular Endothelial Growth Factor A

Angiogenesis is the production of new blood vessels from pre-existing ones. This process is tightly regulated by a series of pro- and anti-angiogenic molecules in normal physiology and when this equilibrium is broken serious consequences may arise. Solid tumors are characterized by a fast growth that eventually pushes cells away from their natural source of oxygen and nutrients from the capillaries. To survive in this hypoxic environment, tumor cells secrete a variety of pro-angiogenic molecules that would elicit proliferation of new blood vessels, thus re-establishing oxygen and nutrient supply. Blockade of angiogenesis may provide a rational approach to managing tumor growth and novel strategies are being developed. The identification of new targets is of paramount importance in the search for a clinically proficient anti-angiogenic therapy. The adrenomedullin family of peptides and gastrin-releasing peptide (GRP) are newly identified pro-angiogenic molecules, secreted by the tumors, whose inhibition results in a considerable reduction of angiogenesis and of tumor growth in animal models. The recent identification of small molecules that reduce the angiogenic effect of these peptides opens new avenues for the development of new anti-tumorigenic drugs.

Topics: Adrenomedullin; Angiogenesis Inhibitors; Angiogenic Proteins; Animals; Antineoplastic Agents; Biological Assay; Gastrin-Releasing Peptide; Humans; Neoplasms; Neovascularization, Pathologic; Peptides; Pyrimidines

The angiogenic activity of peptide adrenomedullin (AM) was first shown in 1998 . Since then, a number of reports have confirmed the ability of AM to induce the growth and migration of isolated vascular endothelial and smooth muscle cells in vitro and to promote angiogenesis in xenografted tumours in vivo. In addition, knockout murine models point to an essential role for AM in embryonic vasculogenesis and ischaemic revascularisation. AM expression is upregulated by hypoxia (a typical feature of solid tumours) and a potential role as a regulator of carcinogenesis and tumour progression has been proposed based on studies in vitro and in animal models. Nevertheless, translational research on AM, and in particular, confirmation of its importance in the vascularisation of human tumours has lagged behind. In this commentary, we review current progress and potential directions for future research into the role of AM in tumour angiogenesis.

Topics: Adrenomedullin; Animals; Cell Hypoxia; Cell Transformation, Neoplastic; Disease Models, Animal; Gene Expression Regulation; Humans; Neoplasms; Neovascularization, Pathologic; Peptides; Signal Transduction; Transplantation, Heterologous

Adrenomedullin (AM) is a 52 amino acid peptide that plays a critical role in several diseases such as hypertension, cancer, diabetes, cardiovascular and renal disorders, among others. Interestingly, AM behaves as a protective agent against some pathologies, yet is a stimulating factor for other disorders. Thus, AM can be considered as a new and promising target for the design of non-peptidic modulators that could be useful for the treatment of those pathologies, by regulating AM levels or the activity of AM. A full decade on from its discovery, much more is known about AM molecular biology and pharmacology, but this knowledge still needs to be applied to the development of clinically useful drugs.

Topics: Adrenomedullin; Animals; Cardiovascular Diseases; Drug Delivery Systems; Drug Design; Humans; Neoplasms; Peptides

Adrenomedullin (ADM) is a 52-amino acid peptide with structural homology to calcitonin gene-related peptide (CGRP) initially isolated from human pheochromocytoma. ADM is synthesized and is secreted from many mammalian tissues, including the adrenal medulla, endothelial and vascular smooth muscle cells, as well as the myocardium and central nervous system. ADM has been implicated as a mediator of several diseases such as cardiovascular and renal disorders, sepsis, inflammation, diabetes and cancer. ADM is also expressed in a variety of tumors, including breast, endometrial and prostate cancer. ADM has been shown to be a mitogenic factor capable of stimulating growth of several cancer cell types. In addition, ADM is a survival factor for certain cancer cells and an indirect suppressor of the immune response. ADM plays an important role in environments subjected to low oxygen tension, which is a typical feature of solid tumors. Under these conditions, ADM is up regulated and acts as a potent angiogenic factor promoting neovascularization. The major focus of this review will be on the role of ADM in cancer, with emphasis on its utility in diagnostic and prognostic terms, along with its relevance as a therapeutic target.

Topics: Adrenomedullin; Animals; Disease Progression; Endometrial Neoplasms; Female; Humans; Male; Neoplasms; Neovascularization, Physiologic; Ovarian Neoplasms; Pancreatic Neoplasms; Prognosis; Prostatic Neoplasms; Protein Biosynthesis; Receptors, Adrenomedullin; Receptors, Peptide; Signal Transduction

Adrenomedullin (AM) is a 52-amino acid peptide with a pluripotential activity. AM is expressed in many tissues throughout the body, and plays a critical role in several diseases such as cancer, diabetes, cardiovascular and renal disorders, among others. While AM is a protective agent against cardiovascular disorders, it behaves as a stimulating factor in other pathologies such as cancer and diabetes. Therefore, AM is a new and promising target for the development of molecules which, through their ability to regulate AM levels, could be used in the treatment of these pathologies.

Topics: Adrenomedullin; Amino Acid Sequence; Animals; Antihypertensive Agents; Cardiovascular Diseases; Diabetes Mellitus; Drug Design; Humans; Molecular Sequence Data; Neoplasms; Peptides; Sequence Alignment

Adrenomedullin (AM) is a 52 amino acid peptide originally isolated from human pheochromocytoma. It was initially demonstrated to have profound effects in vascular cell biology, since AM protects endothelial cells from apoptosis, promotes angiogenesis and affects vascular tone and permeability. This review article summarizes the literature data concerning the relationship between AM and angiogenesis and describes the relationship between vascular endothelial growth factor, hypoxia and AM and tumor angiogenesis. Finally, the role of AM as a potential target of antiangiogenic therapy is discussed.

Topics: Adrenomedullin; Angiogenesis Inhibitors; Animals; Gene Expression; Humans; Hypoxia; Neoplasms; Neovascularization, Pathologic; Neovascularization, Physiologic; Peptides; Vascular Endothelial Growth Factor A

Adrenomedullin (AM) is a peptide that possesses potentially beneficial properties. Since the initial discovery of the peptide by Kitamura et al. in 1993, the literature has been awash with reports describing its novel mechanisms of action and huge potential as a therapeutic target. Strong evidence now exists that AM is able to act as an autocrine, paracrine, or endocrine mediator in a number of biologically significant functions, including the endothelial regulation of blood pressure, protection against organ damage in sepsis or hypoxia, and the control of blood volume through the regulation of thirst. Its early promise as a potential mediator/modulator of disease was not, however, entirely as a result of the discovery of physiological functions but due more to the observation of increasing levels measured in plasma in direct correlation with disease progression. In health, AM circulates at low picomolar concentrations in plasma in 2 forms, a mature 52-amino acid peptide and an immature 53-amino acid peptide. Plasma levels of AM have now been shown to be increased in a number of pathological states, including congestive heart failure, sepsis, essential hypertension, acute myocardial infarction, and renal impairment. These earliest associations have been further supplemented with evidence of a role for AM in other pathologies including, most intriguingly, cancer. In this review, we offer a timely review of our current knowledge on AM and give a detailed account of the putative role of AM in those clinical areas in which the best therapeutic opportunities might exist.

Topics: Adrenomedullin; Animals; Cardiovascular Diseases; Clinical Trials as Topic; Diabetes Mellitus; Humans; Inflammation; Kidney Diseases; Neoplasms; Neovascularization, Pathologic; Peptides; Sepsis

Adrenomedullin (AM) is a pluripotent hormone with structural similarities to calcitonin gene-related peptide (CGRP), which is expressed by many tissues in the body and shows a remarkable range of effects mediated by paracrine/autocrine and possibly endocrine mechanisms. AM has been implicated as a mediator of several pathologies such as cardiovascular and renal disorders, sepsis, inflammation, diabetes and cancer, among others. AM is expressed in a variety of tumors where it aggravates several of the molecular and physiological features of malignant cells. AM has been shown to be a mitogenic factor stimulating growth in several cancer types and to encourage a more aggressive tumor phenotype. In addition, AM is an apoptosis survival factor for cancer cells and an indirect suppressor of the immune response through its binding protein, complement factor H, and regulation in expression of cytokines. AM plays an important role in environments subjected to low oxygen tensions, which is a typical feature in the proximity of solid tumors. Under these conditions, AM is upregulated through a hypoxia-inducible factor 1 (HIF-1)-dependent pathway and acts as a potent angiogenic factor promoting neovascularization. The collective findings brought together over the last years place AM as a major regulator of carcinogenesis-tumor progression and identifies its autocrine loop as a putative target for developing new strategies against human cancers.

Topics: Adrenomedullin; Angiogenesis Inducing Agents; Animals; Apoptosis; Cell Hypoxia; Humans; Immunologic Surveillance; Neoplasms; Peptides; Rats; Receptors, Adrenomedullin; Receptors, Peptide; Signal Transduction

Adrenomedullin (AM) is a recently discovered regulatory peptide involved in many functions including vasodilatation, electrolyte balance, neurotransmission, growth, and hormone secretion regulation, among others. This 52-amino acid peptide is expressed by specific cell types in many organs throughout the body. A complex receptor system has been described for AM; it requires at least the presence of a seven-transmembrane-domain G-protein-coupled receptor, a single-transmembrane-domain receptor activity modifying protein, and a receptor component protein needed to establish the connection with the downstream signal transduction pathway, which usually involves cyclicAMP. In addition, a serum-binding protein regulates the biological actions of AM, frequently by increasing AM functional attributes. Changes in levels of circulating AM correlate with several critical diseases, including cardiovascular and renal disorders, sepsis, cancer, and diabetes. Whether AM is a causal agent, a protective reaction, or just a marker for these diseases is currently under investigation. New technologies seeking to elevate and/or reduce AM levels are being investigated as potential therapeutic avenues.

Topics: Adrenomedullin; Animals; Diabetes Mellitus; Disease Models, Animal; GTP-Binding Proteins; Humans; Neoplasms; Peptides; Receptors, Cell Surface; Signal Transduction; Viscera

Adrenomedullin (AM) is a pluripotent regulatory peptide initially isolated from a human pheochromocytoma (adrenal tumor) and subsequently shown to play a critical role in cancer cell division, tumor neovascularization, and circumvention of programmed cell death, thus it is an important tumor cell survival factor underlying human carcinogenesis. A variety of neural and epithelial cancers have been shown to produce abundant amounts of AM. Recent findings have implicated elevation of serum AM with the onset of malignant expression. In addition, patients with tumors producing high levels of this peptide have a poor prognostic clinical outcome. Given that most human epithelial cancers display a microenvironment of reduced oxygen tension, it is interesting to note that AM and several of its receptors are upregulated during hypoxic insult. The existence of such a regulatory pathway has been implicated as the basis for the overexpression of AM/AM-R in human malignancies, thereby generating a subsequent autocrine/paracrine growth advantage for the tumor cell. Furthermore, AM has been implicated as a potential immune suppressor substance, inhibiting macrophage function and acting as a newly identified negative regulator of the complement cascade, protective properties which may help cancer cells to circumvent immune surveillance. Hence, AM's traditional participation in normal physiology (cited elsewhere in this issue) can be extended to a primary player in human carcinogenesis and may have clinical relevance as a biological target for the intervention of tumor progression.

Topics: Adrenomedullin; Animals; Apoptosis; Disease Progression; Humans; Neoplasms; Neovascularization, Pathologic; Peptides; Rats; Tumor Cells, Cultured

Topics: Adrenomedullin; Animals; Cytokines; Humans; Hypoxia; Neoplasms; Peptide Fragments; Peptides; Phorbol Esters; Protein Precursors; Receptors, Adrenomedullin; Receptors, Peptide; Vasodilator Agents

In this study, we aimed to determine serum adrenomedullin levels and compare them with levels of C-reactive protein (CRP) and procalcitonin (PCT). Cancer patients aged 0-18 years who experienced febrile neutropenia attacks were included in the study. Adrenomedullin, CRP, and PCT were analyzed at admission, day 3, and days 7-10 later. Fifty episodes of febrile neutropenia that developed in 37 patients were analyzed in this study. The mean age of the patients was 7.5 ± 4.7 (1-18) years. The patients had leukemia (73%), solid tumors (19%), and lymphoma (8%). The percentages of the patients in the clinically documented infection (CDI), fever of unknown origin (FUO), sepsis, and microbiological documented infection (MDI) categories were 34%, 34%, 20%, and 12%, respectively. During the study period, four patients were lost. In the MDI group, adrenomedullin levels on day 3 were significantly higher than those in the CDI and FUO groups. PCT levels were significantly higher in the sepsis group than those in the CDI group at admission, day 3, and days 7-10. In the sepsis group, PCT levels on days 7-10 days were significantly higher than those in the sepsis group. PCT values from the deceased patients on days 7-10 were significantly higher than those from patients who survived. CRP levels did not differ significantly among the febrile neutropenia groups. First, in our study, adrenomedullin was used as a biomarker in the febrile neutropenia episodes of children with cancer. Among adrenomedullin, CRP, and PCT, procalcitonin demonstrates the highest correlation with the severity of infection.

Topics: Adolescent; Adrenomedullin; Biomarkers; C-Reactive Protein; Calcitonin; Calcitonin Gene-Related Peptide; Chemotherapy-Induced Febrile Neutropenia; Child; Child, Preschool; Disease-Free Survival; Female; Humans; Infant; Infant, Newborn; Male; Neoplasms; Protein Precursors; Survival Rate

Within the tumor microenvironment, tumor cells and endothelial cells regulate each other. While tumor cells induce angiogenic responses in endothelial cells, endothelial cells release angiocrine factors, which act on tumor cells and other stromal cells. We report that tumor cell-derived adrenomedullin has a pro-angiogenic as well as a direct tumor-promoting effect, and that endothelium-derived CC chemokine ligand 2 (CCL2) suppresses adrenomedullin-induced tumor cell proliferation. Loss of the endothelial adrenomedullin receptor CALCRL or of the G-protein Gs reduced endothelial proliferation. Surprisingly, tumor cell proliferation was also reduced after endothelial deletion of CALCRL or Gs. We identified CCL2 as a critical angiocrine factor whose formation is inhibited by adrenomedullin. Furthermore, CCL2 inhibited adrenomedullin formation in tumor cells through its receptor CCR2. Consistently, loss of endothelial CCL2 or tumor cell CCR2 normalized the reduced tumor growth seen in mice lacking endothelial CALCRL or Gs. Our findings show tumor-promoting roles of adrenomedullin and identify CCL2 as an angiocrine factor controlling adrenomedullin formation by tumor cells.

Topics: Adrenomedullin; Animals; Cell Proliferation; Chemokine CCL2; Chemokines; Endothelial Cells; Ligands; Mice; Neoplasms; Receptors, CCR2; Tumor Microenvironment

Little information is available concerning protein expression of the calcitonin receptor-like receptor (CALCRL) at the protein level. Here, we developed a rabbit monoclonal antibody, 8H9L8, which is directed against human CALCRL but cross-reacts with the rat and mouse forms of the receptor. We confirmed antibody specificity via Western blot analyses and immunocytochemistry using the CALCRL-expressing neuroendocrine tumour cell line BON-1 and a CALCRL-specific small interfering RNA (siRNA). We then used the antibody for immunohistochemical analyses of various formalin-fixed, paraffin-embedded specimens of normal and neoplastic tissues. In nearly all tissue specimens examined, CALCRL expression was detected in the capillary endothelium, smooth muscles of the arterioles and arteries, and immune cells. Analyses of normal human, rat, and mouse tissues revealed that CALCRL was primarily present in distinct cell populations in the cerebral cortex; pituitary; dorsal root ganglia; epithelia, muscles, and glands of the larger bronchi; intestinal mucosa (particularly in enteroendocrine cells); intestinal ganglia; exocrine and endocrine pancreas; arteries, capillaries, and glomerular capillary loops in the kidneys; the adrenals; Leydig cells in the testicles; and syncytiotrophoblasts in the placenta. In the neoplastic tissues, CALCRL was predominantly expressed in thyroid carcinomas, parathyroid adenomas, small-cell lung cancers, large-cell neuroendocrine carcinomas of the lung, pancreatic neuroendocrine neoplasms, renal clear-cell carcinomas, pheochromocytomas, lymphomas, and melanomas. In these tumours with strong expression of CALCRL, the receptor may represent a useful target structure for future therapies.

Topics: Adrenomedullin; Animals; Arteries; Calcitonin Receptor-Like Protein; Humans; Intestinal Mucosa; Intestines; Male; Mice; Neoplasms; Rats

To investigate the value of presepsin and proadrenomedullin (proADM) as new markers for febrile neutropenia, by comparing them with conventional markers.. Plasma specimens for presepsin, proADM, C-reactive protein (CRP), and procalcitonin (PCT) were collected every 3 days during each episode of febrile neutropenia.. A total of 39 patients experiencing a collective 47 episodes of febrile neutropenia with hematological malignant neoplasms, as well as 40 healthy control patients without infectious disease, were enrolled in this study. Levels of the studied analytes in the presepsin 1 group (with baseline values taken at admission), presepsin 2 group (values recorded on the 3rd day of febrile neutropenia), and presepsin 3 group (values recorded on the 6th day of hospitalization) were all higher in the subgroups with bacteremia. C-reactive protein 1 (baseline value taken at admission), procalcitonin 1 (as recorded at admission), and procalcitonin 2 (recorded on the 3rd day of febrile neutropenia) were higher in the subroups with bacteremia (P =.03, P = .04, and P = .04, respectively). In multivariate logistic regression analysis, presepsin 1 and/or PCT 1/CRP 1 combined analysis was superior in predicting bacteremia.. Presepsin could be used in combination with other biomarkers to detect bacteremia.

Topics: Adrenomedullin; Bacteremia; Biomarkers; C-Reactive Protein; Child; Febrile Neutropenia; Hematologic Neoplasms; Humans; Lipopolysaccharide Receptors; Neoplasms; Peptide Fragments; Procalcitonin; Protein Precursors

In this study, we investigated the roles of presepsin (PSP) and midregional proadrenomedullin (mr-proADM) in children with febrile neutropenia (FN) due to chemotherapy.. We assessed 36 FN episodes in 26 children. Patients were classified into bacteremia (B) and fever of unknown origin (FUO) groups. We evaluated PSP and mr-proADM at admission (T0), after 24/48 h (T1), and after 5 days (T2).. PSP and mr-proADM levels were elevated at T0 and significantly decreased at T2. mr-proADM levels did not significantly differ between the B and FUO groups. PSP levels significantly differed between the B and FUO groups only at T1. Both PSP and mr-proADM levels at T0 were a predictor of length of hospital stay but not of the duration of fever. Finally, receiver operating characteristic curve analysis showed that PSP and mr-proADM had low diagnostic accuracy for blood culture positivity.. PSP and mr-proADM display poor clinical usefulness for FN in oncologic children.

Topics: Adrenomedullin; Age Factors; Antineoplastic Combined Chemotherapy Protocols; Biomarkers; Child; Febrile Neutropenia; Female; Humans; Lipopolysaccharide Receptors; Male; Neoplasms; Peptide Fragments; Prognosis; Protein Precursors; ROC Curve

GDF-15 is an established cardiovascular risk marker but is equally implicated in tumour biology. Elevated levels of GDF-15 have indeed been observed in distinct tumour entities. This study aimed to explore the relation of GDF-15 to other cardiac biomarkers and the general association of GDF-15 on prognosis in an unselected cohort of treatment-naïve cancer patients.. We prospectively enrolled 555 consecutive patients at time of diagnosis of malignant disease prior receiving anticancer therapy. Plasma GDF-15 concentrations were determined alongside other cardiac and routine laboratory markers. All-cause mortality was defined as primary endpoint.. GDF-15 levels were 338 ng/L (IQR:205-534) for the total cohort, and values were comparable for different tumour entities except breast cancer. Metastatic disease was characterized by higher plasma GDF-15 [435 ng/L (IQR:279-614) vs 266 ng/L (IQR:175-427), P < .001]. GDF-15 correlated positively with inflammatory status reflected by CRP, SAA and IL-6 [r = .31, P < .001, r = .23, P < .001 and r = .14, P = .002] and cardiac biomarkers as NT-proBNP, hsTnT, MR-proADM and CT-proET-1 [r = .46; r = .46; r = .59 and r = .50; P < .001 for all]. GDF-15 was significantly associated with all-cause mortality after multivariate adjustment [adj.HR for ln(GDF-15) 1.78, 95%CI:1.47-2.16, P < .001]. There was a significant interaction between solid and haematological malignancies with loss of association of GDF-15 with outcome in myelodysplastic and myeloproliferative disease.. Elevated plasma GDF-15 is associated with progressing disease severity and poor prognosis in solid tumours of treatment-naïve cancer patients. GDF-15 increase is accompanied by worsening systemic inflammation and a subclinical functional impairment of different organs including the heart. GDF-15 represents a promising target for our pathophysiologic understanding in cardio-oncology linking conditions of both cardiac and neoplastic disease.

Topics: Adrenomedullin; Aged; Breast Neoplasms; C-Reactive Protein; Cause of Death; Endothelin-1; Female; Gastrointestinal Neoplasms; Glycopeptides; Growth Differentiation Factor 15; Humans; Interleukin-6; Lung Neoplasms; Male; Middle Aged; Mortality; Myelodysplastic Syndromes; Myeloproliferative Disorders; Natriuretic Peptide, Brain; Neoplasm Metastasis; Neoplasms; Peptide Fragments; Prognosis; Proportional Hazards Models; Prospective Studies; Protein Precursors; Serum Amyloid A Protein; Troponin T

Neutropenic fever is a source of morbidity and mortality in children with cancer. It is not possible to detect the causative agent in cultures in most cases; the research for a marker that can show the severity of the disease is ongoing. We evaluated the role of adrenomedullin (ADM) at predicting prognosis on patients with febrile neutropenia, which has been proven to be a good prognostic marker for diseases with high morbidity and mortality, such as heart failure, ischemic ventricular dysfunction, sepsis, and systemic inflammatory response syndrome.. We recorded the 36 febrile episodes of 14 children receiving chemotherapy due to solid tumors. There were 10 events with unknown origin in the low-risk group, while in the high-risk group, there were 17 events with unknown origin, 8 events with microbiological origin and 1 event with clinically proven infection. Cultures were positive only in the high-risk group. However, the changes of ADM levels through time periods (first, second, third, and seventh days) were not significant.. The first-day plasma ADM levels significantly predicted the presence of culture positivity (AUC 0.628, 95% CI 0.40-0.85, p = 0.303) and high-risk patients with neutropenic fever (AUC 0.76, 95% CI 0.56-0.97, p = 0.016).. Our study showed that increased plasma ADM was correlated with high-risk neutropenic fever and culture positivity. The ADM levels in the high-risk group were clearly high at the diagnosis and continued to the end of the treatment.

Topics: Adolescent; Adrenomedullin; Anti-Bacterial Agents; Biomarkers; Child; Child, Preschool; Enzyme-Linked Immunosorbent Assay; Febrile Neutropenia; Fever of Unknown Origin; Humans; Neoplasms; Prognosis; Sensitivity and Specificity; Severity of Illness Index

Patients with cancer may display elevated levels of B-type natriuretic peptide (BNP) and high-sensitive troponin T (hsTnT) without clinical manifestation of cardiac disease. This study aimed to evaluate circulating cardiovascular hormones and hsTnT and their association with mortality in cancer.. We prospectively enrolled 555 consecutive patients with a primary diagnosis of cancer and without prior cardiotoxic anticancer therapy. N-terminal pro BNP (NT-proBNP), mid-regional pro-atrial natriuretic peptide (MR-proANP), mid-regional pro-adrenomedullin (MR-proADM), C-terminal pro-endothelin-1 (CT-proET-1), copeptin, hsTnT, proinflammatory markers interleukin 6 (IL-6) and C reactive protein (CRP), and cytokines serum amyloid A (SAA), haptoglobin and fibronectin were measured. All-cause mortality was defined as primary endpoint.. During a median follow-up of 25 (IQR 16-31) months, 186 (34%) patients died. All cardiovascular hormones and hsTnT levels rose with tumour stage progression. All markers were significant predictors of mortality with HRs per IQR of 1.54 (95% CI 1.24 to 1.90, p<0.001) for NT-proBNP, 1.40 (95% CI 1.10 to 1.79, p<0.01) for MR-proANP, 1.31 (95% CI 1.19 to 1.44, p<0.001) for MR-proADM, 1.21 (95% CI 1.14 to 1.30, p<0.001) for CT-proET-1, 1.22 (95% CI 1.04 to 1.42, p=0.014) for copeptin and 1.21 (95% CI 1.13 to 1.32, p<0.001) for hsTnT, independent of age, gender, tumour entity and stage, and presence of cardiac comorbidities. NT-proBNP, MR-proANP, MR-proADM and hsTnT displayed a significant correlation with IL-6 and CRP.. Circulating levels of cardiovascular peptides like NT-proBNP, MR-proANP, MR-proADM, CT-pro-ET-1 and hsTnT were elevated in an unselected population of patients with cancer prior to induction of any cardiotoxic anticancer therapy. The aforementioned markers and copeptin were strongly related to all-cause mortality, suggesting the presence of subclinical functional and morphological myocardial damage directly linked to disease progression.

Topics: Adrenomedullin; Aged; Asymptomatic Diseases; Atrial Natriuretic Factor; Austria; Biomarkers; C-Reactive Protein; Cardiovascular Diseases; Endothelin-1; Female; Glycopeptides; Humans; Kaplan-Meier Estimate; Male; Middle Aged; Natriuretic Peptide, Brain; Neoplasm Staging; Neoplasms; Peptide Fragments; Prospective Studies; Protein Precursors; Troponin T

Infections in critically ill patients continue to impose diagnostic and therapeutic challenges. We seek to investigate the utility of proadrenomedullin and procalcitonin as diagnostic and prognostic biomarkers in febrile critically ill patients with cancer and compare their performance with that of C-reactive protein.. Single-center prospective cohort study.. Tertiary care, academic, university hospital.. One hundred fourteen critically ill patients with cancer with fever.. None.. Blood samples were withdrawn on the day of fever onset and 4 to 7 days thereafter, and the serum proadrenomedullin, procalcitonin, and C-reactive protein levels were measured using the Kryptor technology afterward. Of the 114 adult patients, 27 had bloodstream infections, 36 had localized infections, and the remaining had no infections. The area under the receiver operating characteristic curve for bloodstream infection diagnosis was significantly greater for proadrenomedullin (0.70; 95% CI, 0.59-0.82) and procalcitonin (0.71; 95% CI, 0.60-0.83) compared with C-reactive protein (0.53; 95% CI, 0.39-0.66) (p = 0.021 and p = 0.003, respectively). Receiver operating characteristic analysis also showed that proadrenomedullin (p = 0.005) and procalcitonin (p = 0.009) each had a better performance than C-reactive protein in predicting patients' mortality within 2 months after their fever onset. Regarding patients' response to antimicrobial therapy, proadrenomedullin, procalcitonin, and C-reactive protein levels all significantly decreased from baseline to follow-up in responders (p ≤ 0.002), whereas only proadrenomedullin level significantly increased in nonresponders (p < 0.0001). In patients with documented infections, proadrenomedullin (0.81; 95% CI, 0.71-0.92) and procalcitonin (0.73; 95% CI, 0.60-0.85) each had a greater area under the curve compared with C-reactive protein (0.59; 95% CI, 0.45-0.73) as for as predicting response (p = 0.004 and p = 0.043, respectively). However, for all febrile patients, proadrenomedullin had a significantly greater area under the curve for predicting favorable response than procalcitonin (p < 0.0001).. In critically ill patients with cancer, proadrenomedullin and procalcitonin both have a promising role in predicting bloodstream infections in a manner more helpful than C-reactive protein. These two biomarkers were superior to C-reactive protein in the prognostic analysis of response to antimicrobial therapy for those patients with documented infections. However, proadrenomedullin was superior to procalcitonin in predicting response in all febrile patients and was unique in showing increased levels among nonresponders.

Topics: Academic Medical Centers; Adrenomedullin; Adult; Aged; Aged, 80 and over; Bacteremia; Biomarkers; C-Reactive Protein; Calcitonin; Calcitonin Gene-Related Peptide; Critical Illness; Female; Humans; Male; Middle Aged; Neoplasms; Prognosis; Prospective Studies; Protein Precursors; ROC Curve; Sepsis

Topics: Adrenomedullin; C-Reactive Protein; Calcitonin; Female; Humans; Male; Neoplasms; Protein Precursors; Sepsis

The risk of developing cancer is regulated by genetic variants, including polymorphisms. Characterizing such variants may help in developing protocols for personalized medicine.. Adrenomedullin is a regulatory peptide involved in cancer promotion and progression. Carriers of a single nucleotide polymorphism (SNP) in the proximity of the adrenomedullin gene have lower levels of circulating peptide. The aim of the present work was to investigate whether carriers of this SNP (rs4910118) are protected against cancer.. This was a retrospective study. DNA samples were obtained from the Carlos III DNA National Bank (University of Salamanca, Salamanca, Spain).. Samples represent a variety of donors and patients from Spain.. DNA from patients with breast cancer (n = 238), patients with lung cancer (n = 348), patients with cardiac insufficiency (n = 474), and healthy donors of advanced age (n = 500) was used.. All samples were genotyped using double-mismatch PCR, and confirmation was achieved by direct sequencing.. The minor allele frequency was calculated in all groups. The Pearson χ(2) was used to compare SNP frequencies.. Of 1560 samples, 14 had the minor allele, with a minor allele frequency in healthy donors of 0.90%. Patients with cancer had a statistically significantly lower frequency than healthy donors (odds ratio = 0.216, 95% confidence interval = 0.048-0.967, P = .028).. Carriers of the minor allele have a 4.6-fold lower risk of developing cancer than homozygotes for the major allele. Knowledge of the rs4910118 genotype may be useful for stratifying patients in clinical trials and for designing prevention strategies.

Topics: Adolescent; Adrenomedullin; Adult; Aged; Aged, 80 and over; Cytoprotection; Female; Genetic Loci; Genetic Predisposition to Disease; Genotype; Humans; Male; Middle Aged; Neoplasms; Polymorphism, Single Nucleotide; Retrospective Studies; Spain; Young Adult

Tumor development requires angiogenesis, and antiangiogenesis has been introduced in the treatment of cancer patients; however, how the cardiovascular phenotype correlates with cancer risk remains ill-defined. Here, we hypothesized that vasoactive peptides previously implicated in angiogenesis regulation predict long-term cancer risk.. We measured midregional proatrial natriuretic peptide (MR-proANP), proadrenomedullin (MR-proADM), and C-terminal preprovasopressin (copeptin) in fasting plasma from participants of the Malmö Diet and Cancer Study that were free from cancer prior to the baseline exam in 1991 to 1994 (1,768 males and 2,293 females). We used Cox proportional hazards models to determine the time to first cancer event in relation to baseline levels of vasoactive peptides during a median follow-up of 15 years.. First cancer events occurred in 366 males and in 368 females. In males, one SD increase of MR-proANP, copeptin, and MR-proADM was independently related to incident cancer [HR (95% CI)] by 0.85 (0.74-0.96), P = 0.012; 1.17 (1.04-1.32), P = 0.009; and 1.12 (0.99-1.26), P = 0.065, respectively, and a summed biomarker score identified an almost 2-fold difference in cancer risk between the top and bottom quartile (P < 0.001). In younger males, the biomarker score identified a more than 3-fold increase in risk between the top and bottom quartile (P < 0.001). Among females, we found no relationship between biomarkers and cancer incidence.. Our data suggest that vasoactive peptide biomarkers predict cancer risk in males, particularly in younger males.. Our findings may have implications for cancer risk prediction and present novel, potentially drug modifiable, mechanisms underlying cancer development.

Topics: Adrenomedullin; Adult; Aged; Atrial Natriuretic Factor; Biomarkers, Tumor; Case-Control Studies; Female; Follow-Up Studies; Glycopeptides; Humans; Male; Middle Aged; Neoplasms; Neovascularization, Pathologic; Peptide Fragments; Prognosis; Prospective Studies; Protein Precursors; Risk Factors; Survival Rate; Sweden

Long-term outcomes in patients surviving community-acquired pneumonia (CAP) are still incompletely understood. This study investigates the association of clinical parameters and blood markers with long-term mortality. We prospectively followed 877 CAP patients from a previous multicentre trial for 18 months follow-up and investigated all-cause mortality following hospital discharge. Overall mortality was 17.3% (95% CI 14.8-19.8%) with a 12.8% (95% CI 10.9-15.0%) mortality incidence rate per year. Initial risk assignment using the Pneumonia Severity Index was accurate during the 18 month follow-up. Multivariable regression models (hazard ratio, 95% CI) designated the following as independent risk factors for long-term mortality: male sex (1.7, 1.2-2.5); chronic obstructive pulmonary disease (1.5, 1.1-2.1); neoplastic disease (2.5, 1.7-3.7); and highest quartile of peak pro-adrenomedullin level (3.3, 1.7-6.2). Initial presentation with temperature>38.7°C (0.4, 0.2-0.6), chills (0.6, 0.4-0.99) and highest quartile of the inflammatory marker C-reactive-protein (0.3, 0.2-0.5) were independent protective factors. A weighted risk score based on these variables showed good discrimination (area under receiver operating characteristic curve 0.78, 95% CI 0.74-0.82). Pronounced clinical and laboratory signs of systemic inflammatory host response upon initial hospital stay were associated with favourable long-term prognosis. Further studies should address whether closer monitoring of high-risk CAP patients after hospital discharge favourably impacts long-term mortality.

Topics: Adrenomedullin; Aged; Aged, 80 and over; C-Reactive Protein; Chills; Community-Acquired Infections; Female; Fever; Humans; Inflammation; Male; Middle Aged; Neoplasms; Pneumonia; Prognosis; Prospective Studies; Protein Precursors; Pulmonary Disease, Chronic Obstructive; Risk; Severity of Illness Index; Sex Factors; Treatment Outcome

The lymphatic vascular system mediates fluid homeostasis, immune defense, and tumor metastasis. Only a handful of genes are known to affect the development of the lymphatic vasculature, and even fewer represent therapeutic targets for lymphatic diseases. Adrenomedullin (AM) is a multifunctional peptide vasodilator that transduces its effects through the calcitonin receptor-like receptor (calcrl) when the receptor is associated with a receptor activity-modifying protein (RAMP2). Here we report on the involvement of these genes in lymphangiogenesis. AM-, calcrl-, or RAMP2-null mice died mid-gestation after development of interstitial lymphedema. This conserved phenotype provided in vivo evidence that these components were required for AM signaling during embryogenesis. A conditional knockout line with loss of calcrl in endothelial cells confirmed an essential role for AM signaling in vascular development. Loss of AM signaling resulted in abnormal jugular lymphatic vessels due to reduction in lymphatic endothelial cell proliferation. Furthermore, AM caused enhanced activation of ERK signaling in human lymphatic versus blood endothelial cells, likely due to induction of CALCRL gene expression by the lymphatic transcriptional regulator Prox1. Collectively, our studies identify a class of genes involved in lymphangiogenesis that represent a pharmacologically tractable system for the treatment of lymphedema or inhibition of tumor metastasis.

Topics: Adrenomedullin; Animals; Calcitonin Receptor-Like Protein; Cell Proliferation; Embryo Loss; Embryonic Development; Endothelial Cells; Female; Homeodomain Proteins; Homeostasis; Intracellular Signaling Peptides and Proteins; Lymphatic Diseases; Lymphatic Vessels; Lymphedema; Male; MAP Kinase Signaling System; Membrane Proteins; Mice; Neoplasm Metastasis; Neoplasms; Neovascularization, Physiologic; Pregnancy; Receptor Activity-Modifying Protein 2; Receptor Activity-Modifying Proteins; Receptors, Calcitonin; Tumor Suppressor Proteins

The preferred conformation of Proadrenomedullin N-Terminal 20 Peptide (PAMP; ARLDVASEFRKKWNKWALSR-amide) has been determined using 1H and 13C two-dimensional nuclear magnetic resonance (NMR) spectroscopy and molecular modeling. PAMP is a peptide that has various physiological functions, including its role as a proangiogenic factor in facilitating tumor growth and its inhibitory effect on catecholamine secretion at nicotinic receptors. The preferred conformation of PAMP was determined in a helix-inducing trifluoroethanol and water (TFE/H2O) solution, and in a membrane-mimetic sodium dodecylsulfate-d25 (SDS) micellar solution. The secondary structure consists of an alpha-helix for residues Arg2 to Arg20 in TFE/H2O solution and an alpha-helix for residues Arg2 to Ala17 in SDS solution. We postulate that the polar charged residues Arg2, Lys12, and Arg20 are responsible for the initial interaction of the peptide with the micelle, and that this is followed by the binding of the hydrophobic residues Leu3, Val5, Phe9, Trp13, and Trp16 to the micellar core. The three C-terminal amino acid residues adopt an extended structure in SDS, suggesting that they are important in receptor recognition and binding. This is supported by truncation studies done by Mahata et al. (Hypertension, 1998, Vol. 32, pp. 907-916), which show the importance of the C-terminal in physiological activity. Furthermore, Belloni et al. (Hypertension, 1999, Vol. 33, pp. 1185-1189), and Martinez et al. (Cancer Research, 2004, Vol. 64, pp. 6489-6494) suggested that the N-terminal was also important in PAMP activity. However, no differences in conformational preference of the N-terminal were observed between the two solvent systems.

Topics: Adrenomedullin; Angiogenesis Inducing Agents; Humans; Magnetic Resonance Spectroscopy; Models, Molecular; Neoplasms; Neovascularization, Pathologic; Peptides; Protein Conformation; Protein Precursors; Solutions

We have previously demonstrated that adrenomedullin (AM) plays a critical role as an autocrine/paracrine tumor cell survival factor. We now present evidence that AM is an important regulator of mast cell (MC) function and that this modulation is potentially involved in tumor promotion. AM induced histamine or beta-hexosaminidase release from rat and human MCs through a receptor-independent pathway. AM was chemotactic for human MCs and stimulated mRNA expression of vascular endothelial growth factor, monocyte chemoattractant protein-1, and basic fibroblast growth factor in this cell type. Differentiated but not undifferentiated human MCs responded to hypoxic insult with elevated AM mRNA/protein expression. Using confocal microscopy, we identified AM-producing MCs in tumor infiltrates of human breast and lung cancer patients. In mixed culture assays the AM-producing human MC line HMC-1 augmented both anchorage-dependent and -independent growth of human lung cancer A549 cells, an effect that was suppressed by MC-targeted siRNA AM knockdown. Finally, HMC-1 cells induced in vivo angiogenesis as assessed by directed in vivo angiogenesis assay analysis; neutralizing anti-AM monoclonal antibody blocked this ability. Our collective data suggest a new role for AM as a cross-talk molecule that integrates tumor and MC communication, underlying a unique promotion mechanism of human cancers.

Topics: Adrenomedullin; Animals; Cell Communication; Cell Line, Tumor; Chemokine CCL2; Chemotaxis, Leukocyte; Fibroblast Growth Factor 2; Humans; Mast Cells; Microscopy, Confocal; Neoplasms; Neovascularization, Pathologic; Peptides; Rats; Receptor Cross-Talk; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Vascular Endothelial Growth Factor A

The cytostatic cytokine tumor necrosis factor-alpha (TNF-alpha) and proliferative hormone adrenomedullin (AM) are abundantly expressed in human tumors. However, little is known about mechanism (s) through which TNF-alpha and AM exert their regulatory effects, especially in the regulation of proliferative activity in malignant cells. Also the role played by TNF-alpha in pathogenesis and treatment of cancer (targeted cancer therapy) remains less understood. The purpose of this study was therefore to characterize the significance of TNF-alpha induced apoptosis with down-regulation of plasma-membrane TNF-alpha receptors and up-regulation of AM receptors with increased production of human AM mRNA, i.e. mechanisms that subsequently control aberrant cellular proliferation in malignant cells. Cytotoxicity, and the whole cell ligand binding assays for TNF-alpha and AM receptors, and RIA-assays of AM production were accomplished in control experiments using pharmacologically pretreated HeLa cells. AM increased proliferation of HeLa cells and AM antagonist (Ala6,21)AM(22-52) significantly antagonized this increase. TNF-alpha inhibitor of cell growth actinomycin-D significantly increased cytotoxicity of TNF-alpha in HeLa cells. Hypoxia increased TNF-alpha production and increased surface-membrane [125I]AM binding. Tumor promotor PMA and histamine down-regulated specific binding of [125I]TNF- alpha on HeLa cells. Mitogenic peptide endothelin-1 increased and specific ET-1 antagonist BQ123 and significantly reduced AM binding. Production of AM in HeLa cells markedly increased after exposure to hypoxia >ET-1 >PMA. BAY11-7082 at concentrations that inhibited IkappaB phosphorylation and thus nuclear translocation and surface membrane TNF-alpha expression increased AM specific binding. Pretreatment of cells inhibitor of HMGCoA reductase inhibitor VULM1457 significantly increased the total number of specific [125I]AM binding sites on HeLa cells. These results suggest relative and contradictory TNF-alpha and AM surface-membrane receptor signaling in HeLa cells and findings reveal a novel proliferative mechanisms that control AM production and thus oncogenic signaling in cells. This implies that several putative inhibitors of TNF-alpha and AM signaling may be considered in oncology for treatment of tumors otherwise nonresponding to cytostatic therapy.

Topics: Adrenomedullin; Cell Death; Cell Proliferation; Enzyme-Linked Immunosorbent Assay; HeLa Cells; Humans; Neoplasms; Peptides; Radioimmunoassay; Tumor Necrosis Factor-alpha

We have found through ex vivo and in vivo angiogenesis models that the adrenomedullin gene-related peptide, proadrenomedullin NH2-terminal 20 peptide (PAMP), exhibits a potent angiogenic potential at femtomolar concentrations, whereas classic angiogenic factors such as vascular endothelial growth factor and adrenomedullin mediate a comparable effect at nanomolar concentrations. We found that human microvascular endothelial cells express PAMP receptors and respond to exogenous addition of PAMP by increasing migration and cord formation. Exposure of endothelial cells to PAMP increases gene expression of other angiogenic factors such as adrenomedullin, vascular endothelial growth factor, basic fibroblast growth factor, and platelet-derived growth factor C. In addition, the peptide fragment PAMP(12-20) inhibits tumor cell-induced angiogenesis in vivo and reduces tumor growth in xenograft models. Together, our data demonstrate PAMP to be an extremely potent angiogenic factor and implicate this peptide as an attractive molecular target for angiogenesis-based antitumor therapy.

Topics: Adrenomedullin; Animals; Calcium; Cell Division; Cell Line, Tumor; Chick Embryo; Endothelium, Vascular; Female; Humans; Mice; Mice, Nude; Neoplasms; Neovascularization, Physiologic; Peptide Fragments; Peptides; Xenograft Model Antitumor Assays

Adrenomedullin (AM) is a regulatory peptide involved in several physiological processes. Among them, AM has been implicated in the regulation of growth, both with mitogenic and antiproliferative activities on normal cells. AM is widely expressed during embryogenesis and may have a significant role in the proliferation and differentiation processes associated with development. AM is also expressed by cancer cell lines and tumors and has been implicated in the growth of malignant cells. Some additional activities associated with AM (antiapoptotic capabilities, angiogenic potential, and upregulation in hypoxic conditions), together with its wide distribution in cancer, suggest that AM may be an important factor in carcinogenesis. Besides its implication in growth, embryogenesis and tumor biology, AM is also involved in pancreatic regulation and diabetes. AM regulates insulin secretion and is overexpressed in the plasma of diabetic patients. Several findings indicate that AM may participate in the pathogenesis and/or clinical complications of this disease.

Topics: Adrenomedullin; Animals; Cell Division; Complement Factor H; Diabetes Mellitus; Humans; Neoplasms; Pancreas; Peptides

Little is known about the molecular mechanisms that control adrenomedullin (AM) production in human cancers. We demonstrate here that the expression of AM mRNA in a variety of human tumor cell lines is highly induced in a time-dependent manner by reduced oxygen tension (1% O2) or exposure to hypoxia mimetics such as desferrioxamine mesylate (DFX) or CoCl2. This AM expression seems to be under hypoxia-inducible factor-1 (HIF-1) transcriptional regulation, since HIF-1alpha and HIF-1beta knockout mouse cell lines had an ablated or greatly reduced hypoxia AM mRNA induction. Similarly, inhibition or enhancement of HIF-1 activity in human tumor cells showed an analogous modulation of AM mRNA. Under hypoxic conditions, immunohistochemical analysis of tumor cell lines revealed elevated levels of AM and HIF-1alpha as compared with normoxia, and we also found an increase of immunoreactive AM in the conditioned medium of tumor cells analyzed by RIA. AM mRNA stabilization was shown to be partially responsible for the hypoxic up-regulated expression of AM. In addition, we have identified several putative hypoxia response elements (HREs) in the human AM gene, and reporter studies with selected HREs were capable of enhancing luciferase expression after exposure to DFX. Furthermore, transient coexpression of HIF-1alpha resulted in an augmented transactivation of the reporter gene after DFX treatment. Given that most solid human tumors have focal hypoxic areas and that AM functions as a mitogen, angiogenic factor, and apoptosis-survival factor, our findings implicate the HIF-1/AM link as a possible promotion mechanism of carcinogenesis.

Topics: Adrenomedullin; Cell Hypoxia; Culture Media, Conditioned; Deferoxamine; DNA; DNA-Binding Proteins; Gene Expression Regulation, Neoplastic; Humans; Hypoxia-Inducible Factor 1; Hypoxia-Inducible Factor 1, alpha Subunit; Immunohistochemistry; Luciferases; Neoplasms; Nuclear Proteins; Oxygen; Peptides; Promoter Regions, Genetic; Response Elements; RNA, Messenger; Transcription Factors; Tumor Cells, Cultured

Adrenomedullin (AM) is a novel vasorelaxing peptide which was originally isolated from the extracts of human pheochromocytoma. It is produced by a number of organs among which the adrenal gland exhibits by far the highest concentrations. The peptide circulates in blood and its plasma levels have been reported to be increased in several diseases such as renal failure and sepsis. In the present study plasma concentrations of AM were measured in various forms of severe illness and compared to clinical and biochemical parameters in order to gain an insight into the factors controlling the plasma levels of this peptide. The highest concentrations of AM were found in patients with sepsis (344.4 +/- 60.4 pg/ml, n = 16) who exhibited up to 12-fold higher levels than a group of healthy subjects (74.1 +/- 4.1 pg/ml, n = 20). Markedly elevated levels were also measured in hemorrhagic (250.1 +/- 37.9 pg/ml, n = 9) and cardiogenic (216.2 +/- 29.4 pg/ml, n = 7) shock as well as in patients with cancer of the gastrointestinal tract (155.6 +/- 32.5 pg/ml, n = 11) or the lungs (146.5 +/- 19.1 pg/ml, n = 22). Plasma AM levels were positively correlated with serum creatinine concentrations in shock (r = 0.06, p < 0.001) and with C-reactive protein levels in patients with cancer (r = 0.64, p < 0.001) or sepsis (r = 0.63, p < 0.01). In order to examine the potential role of the adrenal gland as a site of AM release, hypoglycemia was induced in a group of healthy volunteers by graded infusion of insulin. Despite a more than 20-fold increase in plasma adrenalin indicating maximal stimulation of the adrenal medulla, no significant alterations of the plasma AM levels were observed. The study demonstrates that not only sepsis but also various forms of cancer and shock are associated with high levels of circulating AM. The correlation with C-reactive protein levels suggests a role of cytokines in mediating the elevations in plasma AM observed in sepsis and cancer. Reduced clearance of the peptide by the kidneys may be one of the mechanisms involved in the accumulation of AM in shock. The adrenal gland appears not to be a major source for circulating AM.

Topics: Adrenal Medulla; Adrenomedullin; Adult; Aged; Aged, 80 and over; C-Reactive Protein; Case-Control Studies; Female; Gastrointestinal Hemorrhage; Humans; Kidney Failure, Chronic; Male; Middle Aged; Neoplasms; Peptides; Shock, Cardiogenic; Systemic Inflammatory Response Syndrome; Vasodilator Agents

Topics: Adrenomedullin; Animals; Anti-Infective Agents; Antihypertensive Agents; Antineoplastic Agents; Apoptosis; Cardiovascular Diseases; Humans; Neoplasms; Peptides; Wound Healing

Although adrenomedullin (AM) previously has been identified in human tumors, its role has remained elusive. Analysis by reverse transcriptase-polymerase chain reaction (RT-PCR) revealed AM mRNA in 18 of 20 human normal tissues representing major organs, and 55 of 58 (95%) malignant cell lines. Western blot and high performance liquid chromatography analysis showed immunoreactive AM species of 18, 14, and 6 kDa that are consistent with the precursor, intermediate product, and active peptide, respectively. Immunohistochemistry and in situ RT-PCR performed on paraffin-embedded tumor cell lines of various tissue origins exhibited AM cytoplasmic staining. Neutralizing monoclonal antibody to AM inhibits tumor cell growth in a concentration-dependent manner, an effect that was reversed with the addition of exogenous AM. Responding tumor cells were shown to have approximately 50,000 AM receptors per cell by Scatchard analysis with 125I-AM and expressed AM receptor mRNA by RT-PCR. Our data showed 36 of 48 (75%) tumor cell lines expressed AM receptor mRNA by RT-PCR assessment, all of them also expressed AM. In the presence of AM, cAMP levels were shown to increase in tumor cells. Our collective data demonstrate that AM and AM receptor are expressed in numerous human cancer cell lines of diverse origin and constitute a potential autocrine growth mechanism that could drive neoplastic proliferation.

Topics: Adrenomedullin; Antihypertensive Agents; Cell Division; Cell Line; Cloning, Molecular; Cyclic AMP; Dose-Response Relationship, Drug; Humans; Immunohistochemistry; Membrane Proteins; Molecular Sequence Data; Neoplasms; Peptides; Polymerase Chain Reaction; Receptors, Adrenomedullin; Receptors, Peptide; RNA, Messenger; RNA, Neoplasm; Signal Transduction; Tumor Cells, Cultured