Cancer, inflammation and the AT1 and AT2 receptors
© Smith and Missailidis; licensee BioMed Central Ltd. 2004
Received: 05 July 2004
Accepted: 30 September 2004
Published: 30 September 2004
The critical role of inappropriate inflammation is becoming accepted in many diseases that affect man, including cardiovascular diseases, inflammatory and autoimmune disorders, neurodegenerative conditions, infection and cancer.
This review proposes that cancer up-regulates the angiotensin II type 1 (AT1) receptor through systemic oxidative stress and hypoxia mechanisms, thereby triggering chronic inflammatory processes to remodel surrounding tissue and subdue the immune system. Based on current literature and clinical studies on angiotensin receptor inhibitors, the paper concludes that blockade of the AT1 receptor in synergy with cancer vaccines and anti-inflammatory agents should offer a therapy to regress most, if not all, solid tumours.
With regard to cancer being a systemic disease, an examination of supporting evidence for a systemic role of AT1 in relationship to inflammation in disease and injury is presented as a logical progression. The evidence suggests that regulation of the mutually antagonistic angiotensin II receptors (AT1 and AT2) is an essential process in the management of inflammation and wound recovery, and that it is an imbalance in the expression of these receptors that leads to disease.
In consideration of cancer induced immune suppression, it is further postulated that the inflammation associated with bacterial and viral infections, is also an evolved means of immune suppression by these pathogens and that the damage caused, although incidental, leads to the symptoms of disease and, in some cases, death.
It is anticipated that manipulation of the angiotensin system with existing anti-hypertensive drugs could provide a new approach to the treatment of many of the diseases that afflict mankind.
Tumour and Inflammation
Tumour has been linked with inflammation since 1863, when Rudolf Virchow discovered leucocytes in neoplastic tissues and made the first connection between inflammation and cancer . Since then, chronic inflammation has been identified as a risk factor for cancer and even as a means to prognose/diagnose cancer at the onset of the disease. Examples of such association include the Human papiloma virus (HPV) and cancer , including cervical , cancers of the oesophagus  and larynx , Helicobacter pylori bacterial infection and gastric adenocarcinoma , the hepatitis B virus, cirrhosis and hepato-cellular carcinoma , Schistosoma haematobium and cancer of the bladder , asbestos induced inflammation and bronchogenic carcinoma or mesothelioma in humans .
Several reports implicate inflammation as a significant risk factor in cancer development: asbestos, cigarette smoke and inflammation of the bowel and pancreas are but a few well-known examples given [1, 10]. These papers demonstrate that the inflammation environment is one that would support tumour development and is consistent with that observed in tumour sites. The relationship of cancer with inflammation is, however, not limited to the onset of the disease due to chronic inflammation. Schwartsburd  goes a step further and proposes that chronic inflammation occurs due to tumour environment stress and that this would generate a protective shield from the immune system. It has been recently demonstrated that the tumour microenvironment highly resembles an inflammation site, with significant advantages for the progression of tumour, including the use of cytokines, chemokines, leucocytes, lymphocytes and macrophages to contribute to both vassal dilation and neovascularisation for increased blood flow, the immunosuppression associated with the malignant disease, and tumour metastasis [1, 11]. Furthermore, this inflammation-site tumour-generated microenvironment, apart from its significant role in cancer progression and protection from the immune system, has a considerable adverse effect to the success of the various current cancer treatments. It has recently been demonstrated that the inflammatory response in cancer can greatly affect the disposition and compromise the pharmacodynamics of chemotherapeutic agents .
It is evident that cancer is using natural inflammatory processes to spread and, unlikely as it seems at first, it is proposed that this is through the use of the angiotensin II type 1 (AT1) receptor.
AT receptors and inflammation
Angiotensin II (Ang II) is a peptide hormone within the renin-angiotensin system (RAS), generated from the precursor protein angiotensinogen, by the actions of renin, angiotensin converting enzyme, chymases and various carboxy- and amino-peptidases . Ang II is the main effector of the RAS system, which has been shown to play an important role in the regulation of vascular homeostasis, with various implications for both cardiovascular diseases and tumour angiogenesis. It exerts its various actions to the cardiovascular and renal systems via interactions with its two receptor molecules, angiotensin II type 1 receptor (AT1) and angiotensin II type 2 receptor (AT2) . AT1 and AT2 receptors have been identified as seven transmembrane-spanning G protein-coupled receptors , comprising an extracellular, glycosylated region connected to the seven transmembrane α-helices linked by three intracellular and three extracellular loops. The carboxy-terminal domain of the protein is cytoplasmic and it is a regulatory site. AT1 is 359 amino acids, while AT2 is 363 amino acids being ~30% homologous to AT1 and are both N-linked glycosylated post-translationally. Various studies have looked at the pharmacological properties of the two receptors and the expression of those receptors on various cell lines. Their affinity for the angiotensin II peptide and their ability to perform their physiological functions has been characterised using radioligand binding analyses and Scatchard plots. The results have indicated that both receptors have high binding affinities for the AngII peptide. The AT1 receptor has demonstrated a Kd of 0.36 nM for the AngII peptide , whereas the AT2 receptor has demonstrated a Kd of 0.17 nM respectively, under similar studies .
AT1 receptors are expressed in various parts of the body and are associated with their respective functions, such as blood vessels, adrenal cortex, liver, kidney and brain, while AT2 receptors are highest in fetal mesenchymal tissue, adrenal medulla, uterus and ovarian follicles . The opposing roles of the AT1 and AT2 receptors in maintaining blood pressure, water and electrolyte homeostasis are well established. It is, however, becoming recognised that the renin-angiotensin system is a key mediator of inflammation , with the AT receptors governing the transcription of pro-inflammatory mediators both in resident tissue and in infiltrating cells such as macrophages.
In addition to the mediators reviewed by Suzuki et al (2003) , a number of vital molecules in inflammatory processes are induced by the AT1 receptor. These include interleukin-1 beta (IL-1b) in activated monocytes , Tumour Necrosis Factor-alpha (TNF-α) , Plasminogen Activator Inhibitor Type 1 (PAI-1)  and adrenomedullin  all of which have been shown to have active participation in various aspects of cancer development. Activation of AT1 also causes the expression of TGF-β [21, 22] and a review of literature indicates this may be a unique capability for this receptor. TGF-β is a multifunctional cytokine that is produced by numerous types of tumours and amongst its many functions is the ability to promote angiogenesis, tissue invasion, metastasis and immune suppression . It has been postulated that the low response rates achieved in cancer patients undergoing immunotherapy is in part caused by tumour expression of TGF-β and this is supported by inhibition of the antigen-presenting functions and anti-tumour activity of dentritic cell vaccines .
On examination of the tumour environment, it is interesting to note that angiotensin II actually increases vasodilation, a phenomenon that researchers have attempted to utilise for drug delivery . This would imply something unusual about the presentation of angiotensin receptors; however it is predominantly over expression of the vasoconstrictor AT1 that is reported in association with human cancers of the breast , pancreas , kidney , squamous cell carcinoma , keratoacanthoma , larynx , adrenal gland , and lung . AT2 has been identified as expressed in preference to AT1 in only one case, in an earlier paper on colorectal cancer .
Is it evolution that causes over expression of AT1?
In the 'Hallmarks of Cancer', the authoritative work by Douglas Hanahan and Robert A. Weinberg, the evolutionary acquired capabilities necessary for cancer cells to become life-threatening tumours are described. Furthermore, it is suggested that cancer researchers should look not just at the cancer cells, but also at the environment in which they interact, with cancers eliciting the aid of fibroblasts, endothelial cells and immune cells .
Sustained angiogenesis, tissue invasion and metastasis are the latter of six necessary steps in tumour progression, as described in the 'Hallmarks of Cancer' . These envisaged evolutionary steps allow cancers to progress from growths of <2 mm to full tumors. A single evolutionary step, however, upregulation of AT1 would provide a considerable advantage to cancer cells that have learnt to evade the apoptosis and growth regulatory effects of TGF-β. Supporting this hypothesis is the observed genetic change from non-invasive cancer esophageal cell line T.Tn to invasive cancer cell line T.Tn-AT1. This genetic change concerns 9 genes, all of which are known to influence inflammation signalling (8 down and 1 up regulated) .
Is it environment?
The alternative basis under which induction of AT1 in tumours may occur is by looking at the environment under which the cancer is developing. Stresses and cell damage on the growing tumour boundary could potentially be causing the expression of AT1. Evidence that appears to support this view can be found in a study of AT1 expression in breast cancers . In this case, in situ carcinoma has over-expressed AT1 receptors in addition to expressing proteins for yet more AT1. In the invasive carcinoma, high proportions of AT1 receptors are found on the tumour boundary, but in this case protein generation for AT1 is very noticeably absent. How could this behaviour be explained? Perhaps the answer lies in oxidative stress and hypoxia.
The formation of oxidised LDL by monocytes and macrophages at the sites of tissue damage has been established in a recent report by Jawahar L. Mehta and Dayuan Li . In this study, the ox-LDL LOX-1 receptor is noted to be induced by fluid shear stress (4 hrs), TNF-α (8 hrs) and self-induced by ox-LDL (12 hrs). Of particular interest is that activation of LOX-1 by ox-LDL induces the expression of the AT1 receptor . This key role of ox-LDL regarding AT1 is demonstrated by HMG Co-A reductase inhibitor causing the down-regulation of the AT1 receptor with consequential reduction in inflammatory response . Also of interest is that another marker of many diseases, homocysteine, enhances endothelial LOX-1 expression .
Hypoxia has been demonstrated to induce the expression of both AT1b (AT1a and AT1b are subsets of AT1) and AT2 receptors in the rat carotid body and pancreas [39, 40]. The expression of AT1 and AT2 receptors has been studied during the development and regression of hypoxic pulmonary hypertension . Hypoxia has been shown to strongly induce the expression of AT1b but not AT1a. The expression of AT2 is believed to protect the cell from apoptosis and this effect has been demonstrated in the brain when AT1 is antagonized . Since HIF-1α governs many hypoxia driven transcriptions , its control of AT1b and AT2 expression can be hypothesized. AT1 activation has also been shown to increase the activity of HIF-1α , and is consistent with other cases of AT1 providing a positive feedback mechanism. Since hypoxia counts for the expression of AT1b, the speculation that the AT1a subtype is induced by oxidative stress is tempting, although a review of literature appears absent in this regard and further investigation is required to confirm this hypothesis.
A combination therapy for cancer
The evidence relating to over-expression of AT1 with cancer progression is compelling. To this effect, AT1 blockade has been hypothesised as the mechanism to overcome cancer associated complications in organ graft recipients . Additionally, a study undertaken in 1998 suggested that hypertensive patients taking ACE inhibitors were significantly less at risk of developing cancer than those taking other hypertensive treatments .
Tumour progression has been significantly slowed with AT1 receptor antagonists [47, 48]. The results appeared to far exceed the expectations of simple inhibition of angiogenesis. Reduction of MCP-1 was noted , as was the expression of many pro-inflammatory cytokines. The activity of tumour-associated macrophages was also noticed to be severely impaired . The importance in reducing the action of tumour-associated macrophages in extracellular matrix decomposition is not to be underestimated, since, in this action, they further progress remodelling by releasing stored TGF-β . The similarity of action of tumour associated macrophages with those in the tissue healing and repair environment has been noted . The tumour suppressant action of tranilast, an AT1 antagonist,  has been more widely explored [51–54]. In one study on the inhibition of uterine leiomyoma cells, Tranilast also induced p21 and p53 . Similarly, the AT1 blocker losartan has been shown to antagonise platelets, which are thought to modulate cell plasticity and angiogenesis via the vascular endothelial growth factor (VEGF) . It has been postulated that losartan and other AT1 blockers can act as novel anti-angiogenic, anti-invasive and anti-growth agents against neoplastic tissue . Furthermore, it has been shown that angiotensin II induces the phosphorylations of mitogen-activated protein kinase (MAPK) and signal transducer and activator of transcription 3 (STAT3) in prostate cancer cells. In contrast, AT1 inhibitors have been shown to inhibit the proliferation of prostate cancer cells stimulated with EGF or angiotensin II, through the suppression of MAPK or STAT3 phosphorylation . Angiotensin II also induces (VEGF), which plays a pivotal role in tumour angiogenesis and has been the target of various therapeutics, including antibodies and aptamers . Although the role of angiotensin II in VEGF-mediated tumour development has not yet been elucidated, an ACE inhibitor significantly attenuated VEGF-mediated tumour development, accompanying the suppression of neovascularisation in the tumour and VEGF-induced endothelial cell migration . Perindopril, another ACE inhibitor has also been shown to be a potent inhibitor of tumour development and angiogenesis through suppression of the VEGF and the endothelial cell tubule formation .
The powerful direct and indirect suppression effects of TNF-α , IL-1β  and TGF-β  on APC presenting cells, NK, T and B cell have been reviewed . The expression of these mediators makes an effective immune response most unlikely.
Despite this, it has long been established that the body does have the capability to recognise cancer cells and develop antigens. Dentritic cell vaccines for instance have been developed and have demonstrated limited effect in treating established tumours. The effectiveness of one such approach was greatly enhanced leading to complete regression of tumours in 40% of cases when TGF-β was neutralised using TGF-β monoclonal antibodies in synergy with a dentritic cell vaccine .
Strong evidence suggests that tumour cells over-express AT1 receptors and compelling evidence has been presented on the implications of AT1 in cancer progression. Although still at a theoretical stage, this evidence leads to the formulation of the hypothesis that effective blockade of AT1 with a tight binding receptor antagonist, in combination with NSAIDs to further control the inflammation, and immunotherapy, such as cancer vaccines, would provide an effective treatment. Most, if not all, solid tumours utilise inflammation processes, which, through the over-expression and activation of AT1 and the subsequent expression of a number of inflammatory cytokines and chemokines, allow for tumour protection from the immune system through immunosuppression, as well as tumour progression and metastasis. Blocking these pathways through inhibition of AT1 using one of the commercially available AT1 inhibitors, whilst lifting the induced protective effect of immunosuppression and further reducing inflammation with the use of NSAIDs will both inhibit tumour progression and allow currently developed immunotherapies, such as cancer vaccines, to promote their therapeutic effect uninhibited. The role of AT1 post-metastasis, given the observation that AT1 protein expression ceases, as demonstrated in the breast cancer study, requires further investigation . However, the premise for the necessity of immunosuppression by cancer is none the less fundamental and this is encouraging for the prospects of regression of cancers that have progressed to metastasis by combinational AT1 blockade/immune therapy.
Learning from Cancer: wound management
Cancer is a systemic disease, one that can affect every part and organ in the body and, as presented in this review so far with regards to the role of AT1 in cancer, AT1 upregulation is of the utmost importance in the activation of inflammation. Systemically, therefore, what purpose does this upregulation of AT1 serve? The release of ACE and extended expression of AT1 and AT2 during the healing process following vascular injury helps to answer this question . AngII is demonstrated to promote migration and proliferation of smooth muscle cells, as well as production of extracellular matrix through AT1 activation. In this work , the AT1 and AT2 receptors are recognized as having a substantial role in the tissue repair and healing processes of injured arteries. Although further literature in regard to the role of AT1 and AT2 in the healing process appears absent and additional studies are required, it appears rational that a systemic agent for the management of inflammation and healing would be one associated with the vascular system.
Confirming the systemic role of the AT1 receptor in inflammation and disease
AT1 as a key inductor of inflammation and disease. A wide range of pro-inflammatory mediators, cytokines, chemokines and surface adhesion moleculesinvolved in a number of diseases are induced by AT1 and thus inhibited by its blockade.
Mediators inhibited by AT1 blockade
NFκB, 'markers of oxidation inflammation and fibrinolysis'
TNF-α, IL-6, ICAM-1, VCAM-1
Surface adhesion molecules
MCP in Hypercholesterolemia associated endothelial dysfunction
None noted in this study.
(Key markers of the disease)
Liver fibrosis and cirrhosis
'TGF-β and pro-inflammatory cytokines'
None noted in this study.
'Markers of inflammation'
Alzheimer's, Huntington's and Parkinson's
(TGF-β , over expression of AT1 and AT2 noted in affected brain areas)
It is clear that a number of diseases, including heart and kidney disease, diseases associated with the liver and pancreas, as well as diseases of the skin, bone, the brain and most of the autoimmune and inflammatory disorders, are all affected by the AT1 blockade. It is worth noting at this stage that many of these diseases are often considered to be associated with ageing and with fibrosis. An investigation of the action of IGF-1 in the regulation of expression of AT2 leads to an explanation of this association.
Role of IGF-1 in regulating AT receptors
The majority of studies on AT1 are related to cardiovascular disease, for which AT1 receptor antagonists were generated as treatment. Regarding AT2, although there has been increased research and interest in its role, this area appears little explored. That which has been learnt so far about the interplay and regulation of these receptors lends itself to a potentially useful model for the management of inflammation:
The expression of AT1 and AT2 receptors on fibroblasts present in cardiac fibrosis is investigated . These types of fibroblast are noted for their expression of AT1 and AT2 receptors. The presence of IL-1b, TNF-α and lipopolysaccharides, through induction of NO and cGMP, all serve to down-regulate AT2 with no effect on AT1 leading to a quicker progression of fibrosis. Interestingly, the continuance in the presence of pro-inflammatory signals serves to delay expression of AT2. This is confirmed in a separate study of AT2 expression in proliferating cells. TGF-β1 and bFGF are shown as powerful inhibitors of AT2 expression, whilst IGF-1 is shown to induce the expression of AT2 .
IGF-1 is principally produced by the liver from GH (Growth Hormone) and circulates in the blood (decreasing with age) and is important in the regulation of immunity and inflammation : IGF-1 is also capable of being produced by fibroblasts and macrophages on induction by pro-inflammatory cytokines, including TNF-α and IL-1b. In addition to the induction of AT2, IGF-1 can be seen as responsible for mediating the actions of many active cells in the immune/inflammation response . Of note is that TNF-α and IL-1b also affect the circulating expression of IGF-1 by feedback on the release of GH from the anterior pituitary.
The controlling role of AT receptors in inflammation and healing
Significant evidence has been shown that AT1 receptors are upregulated during disease and that AT2 receptor expression follows behind AT1 expression during injury and healing. Given the opposing roles of AT1 and AT2 it can thus be postulated that the interplay of these receptors plays a significant part in judging the current local status of appropriate versus inappropriate inflammation and in providing feedback to the rest of the body. Indeed it is anticipated that prolonged expression of AT1 combined with a lack of AT2 expression results in sustained chronic inflammation and fibrosis.
The invasiveness and immunosuppression of many cancers appears dependent on inflammation and the upregulation of AT1. Two mechanisms for upregulation of AT1 are discussed: 1) evolutionary changes to take advantage of this pro-inflammatory control mechanism, 2) AT1 expression induced by an alternating environment of hypoxia and oxidative stress. Immunosuppression as a common protection mechanism of solid tumours against immune responses has been verified from current literature and experimental procedures, as has the implication of cytokines and chemokines in tumour growth and metastasis. Given the involvement of AT1 in the immunosuppression and inflammatory processes, as well as in the expression of the pro-inflammatory cytokines and chemokines, it becomes evident that the AT1 receptor is essential for tumour protection and progression. A combination therapy consisting of AT1 receptor antagonists, NSAID for further control of the inflammation and immune therapy in the form of tumour vaccines should provide a novel and successful treatment for solid tumours.
In the renin-angiotensin system, the angiotensin II receptors AT1 and AT2 seem to have opposing functions. The actions of AT1 being principally pro-inflammatory whilst AT2 provides protection against hypoxia, draws inflammatory action to a close and promotes healing. The various direct and indirect mechanisms for feedback between the receptors, their induced products and the external hormonal system in the control of inflammation and healing are summarised in a highly simplified model which none the less can be used to explain how many key promoters and inhibitors of disease exert their effects.
From a review of the current disease literature, it has been demonstrated that the role of AT1 and AT2 in inflammation is not limited to cancer-associated inflammation, but is generally consistent and system wide. Potential therapy by manipulation of these receptors, although at an early stage, has been demonstrated for some of these diseases and it is proposed that this approach will provide an effective basis for the treatment of autoimmune, inflammatory and neurodegenerative disorders using existing drugs. AT1 receptor blockade should, in addition, provide a treatment to alleviate the damage caused by bacterial and viral infections, where their destructive action is through chronic inflammation. Given the importance of the immune suppressant effect of inflammation in cancer, it is anticipated that AT1 blockade should also serve to elicit a more effective immune response to other invaders that seek to corrupt the wound recovery process.
Manipulation of the AT1 and AT2 receptors has profound and exciting implications in the control of disease.
List of abbreviations used
- TGF-β :
Transforming Growth Factor Beta
Angiotensin II Type 1 receptor
Angiotensin II Type 2 receptor
Insulin-like Growth Factor 1
Lectin-like Oxidized Low-Density Lipoprotein Receptor 1
Hypoxia Induced Factor 1 Alpha
- HMG CoA:
3-Hydroxy-3-Methyl-Glutaryl Coenzyme A
basic Fibroblast Growth Factor
Reactive Oxygen Species (most notably O2-.)
Many thanks to Jim Iley of the Open University not only for S807 Molecules in Medicine but also for suggesting the title of this paper.
- Balkwill F, Mantovani A: Inflammation and cancer: back to Virchow?. Lancet. 2001, 357: 539-545. 10.1016/S0140-6736(00)04046-0.PubMedView ArticleGoogle Scholar
- Munger K: The role of human papillomaviruses in human cancers. Frontiers in Bioscience. 2002, 7: D641-D649.PubMedView ArticleGoogle Scholar
- Castle PE, Hillier S, Rabe L, Hildesheim A, Herrero R, Bratti M, Sherman M, Burk R, Rodriguez A, Alfaro M, Hutchinson M, Morales J, Schiffman M: An Association of Cervical Inflammation with High-Grade Cervical Neoplasia in Women Infected with Oncogenic Human Papillomavirus (HPV). Cancer Epidemiol Biomarkers Prev. 2001, 10: 1021-1027.PubMedGoogle Scholar
- Syrjanen KJ: HPV infections and oesophageal cancer. Journal of Clinical Pathology. 2002, 55: 721-728. 10.1136/jcp.55.10.721.PubMedPubMed CentralView ArticleGoogle Scholar
- Aaltonen LM, Rihkanen H, Vaheri A: Human papillomavirus in larynx. Laryngoscope. 2002, 112 (4): 700-707. 10.1097/00005537-200204000-00020.PubMedView ArticleGoogle Scholar
- Naumann M, Crabtree J: Helicobacter pylori-induced epithelial cell signalling in gastric carcinogenesis. Trends in Microbiology. 2002, 12: 29-36. 10.1016/j.tim.2003.11.005.View ArticleGoogle Scholar
- Hilleman M: Critical overview and outlook: pathogenesis, prevention, and treatment of hepatitis and hepatocarcinoma caused by hepatitis B virus. Vaccine. 2003, 21: 4626-4649. 10.1016/S0264-410X(03)00529-2.PubMedView ArticleGoogle Scholar
- Rosin MP, Anwar WA, Ward AJ: Inflammation, chromosomal instability and cancer: the schistosomiasis model. Cancer Res. 1994, 54 (7 Suppl): 1929S-1933S.PubMedGoogle Scholar
- Manninga C, Vallyathanb V, Mossman B: Diseases caused by asbestos: mechanisms of injury and disease development. International Immunopharmacology. 2002, 2: 191-200. 10.1016/S1567-5769(01)00172-2.View ArticleGoogle Scholar
- Farrow B, Evers BM: Inflammation and the development of pancreatic cancer. Surgical Oncology. 2002, 10: 153-169. 10.1016/S0960-7404(02)00015-4.PubMedView ArticleGoogle Scholar
- Schwartsburd PM: Chronic inflammation as inductor of pro-cancer microenvironment: Pathogenesis of dysregulated feedback control. Cancer and Metastasis reviews. 2003, 22: 95-102. 10.1023/A:1022220219975.PubMedView ArticleGoogle Scholar
- Slaviero KA, Clarke SJ, Rivory LP: Inflammatory response: an unrecognised source of variability in the pharmacokinetics and pharmacodynamics of cancer chemotherapy. Lancet Oncol. 2003, 4: 224-32. 10.1016/S1470-2045(03)01034-9.PubMedView ArticleGoogle Scholar
- Thomas WG, Mendelsohn FAO: Molecules in Focus Angiotensin receptors: form and distribution. IJBCB. 2003, 35: 774-779. 10.1016/S1357-2725(02)00263-7.Google Scholar
- Martin MM, Victor X, Zhao X, McDougall JK, Elton TS: Identification and characterization of functional angiotensin II type 1 receptors on immortalized human fetal aortic vascular smooth muscle cells. Molecular and Cellular Endocrinology. 2001, 183: 81-91. 10.1016/S0303-7207(01)00595-0.PubMedView ArticleGoogle Scholar
- Moore SA, Patel AS, Huang N, Lavin BC, Grammatopoulos TN, Andres RD, Wayhenmeyer JA: Effects of mutations in the highly concerved DRY motif on binding affinity, expression, and G-protein recruitment of the human angiotensin II type-2 receptor. Molecular Brain Res. 2002, 109: 161-167. 10.1016/S0169-328X(02)00552-1.View ArticleGoogle Scholar
- Suzuki Y, Ruiz-Ortega M, Lorenzo O, Ruperez M, Esteban V, Egido J: Inflammation and angiotensin II. IJBCB. 2003, 35: 881-900. 10.1016/S1357-2725(02)00271-6.Google Scholar
- Dorffel Y, Latsch C, Stuhlmuller B, Schreiber S, Scholze S, Burmester GR, Scholze J: Preactivated Peripheral Monocytes in Patients with Essential Hypertension. Hypertension. 1999, 34: 113-117.PubMedView ArticleGoogle Scholar
- Tsutamoto T, Wada A, Maeda K, Mabuchi N, Hayashi M, Tsutsui T, Ohnishi M, Sawaki M, Fujii M, Matsumoto T, Kinoshita M: Angiotensin II type 1 receptor antagonist decreases plasma levels of tumor necrosis factor alpha, interleukin-6 and soluble adhesion molecules in patients with chronic heart failure. Journal of the American College of Cardiology. 2000, 35: 715-721. 10.1016/S0735-1097(99)00594-X.View ArticleGoogle Scholar
- Chen HC, Bouchie J, Perez A, Clermont A, Izumo S, Hampe J, Feener E: Role of the Angiotensin AT1 Receptor in Rat Aortic and Cardiac PAI-1 Gene Expression. Arteriosclerosis, Thrombosis, and Vascular Biology. 2000, 20: 2297-PubMedView ArticleGoogle Scholar
- Mishima K, Kato J, Kuwasako K, Imamura T, Kitamura K, Eto T: Angiotensin II modulates gene expression of adrenomedullin receptor components in rat cardiomyocytes. Life Sciences. 2003, 73: 1629-35. 10.1016/S0024-3205(03)00484-3.PubMedView ArticleGoogle Scholar
- Leung PS, Suen PM, Ip SP, Yip CK, Chen G, Paul BS, Lai PBS: Expression and localization of AT1 receptors in hepatic Kupffer cells: its potential role in regulating a fibrogenic response. Regulatory Peptides. 2003, 116: 61-69. 10.1016/S0167-0115(03)00192-7.PubMedView ArticleGoogle Scholar
- Rosenkranz S: TGF-beta1 and angiotensin networking in cardiac remodeling. Cardiovasc Res. 2004, 63: 423-432. 10.1016/j.cardiores.2004.04.030.PubMedView ArticleGoogle Scholar
- Teicher B: Malignant cells, directors of the malignant process: Role of transforming growth factor-beta. Cancer and Metastasis reviews. 2001, 20: 133-143. 10.1023/A:1013177011767.PubMedView ArticleGoogle Scholar
- Kobie JJ, Wu RS, Kurt RA, Lou S, Adelman MK, Whitesell LJ, Ramanathapuram LV, Arteaga CL, Akporiaye ET: Transforming Growth Factor β Inhibits the Antigen-Presenting Functions and Antitumor Activity of Dendritic Cell Vaccines. Cancer Research. 2003, 63: 1860-1864.PubMedGoogle Scholar
- Maeda H, Fang J, Inutsuka T, Kitamoto Y: Vascular permeability enhancement in solid tumors: various factors, mechanisms involved and its implications. International Immunopharmacology. 2003, 3: 319-328. 10.1016/S1567-5769(02)00271-0.PubMedView ArticleGoogle Scholar
- Tahmasebi M, Puddefoot JR, Inwang ER, Goode AW, Carpenter R, Vinson GP: Transcription of the prorenin gene in Normal and Diseased Breast. Eur J Cancer. 1998, 34: 1777-1782. 10.1016/S0959-8049(98)00173-7.PubMedView ArticleGoogle Scholar
- Fujimoto Y, Sasaki T, Tsuchida A, Chayama K: Angiotensin II type 1 receptor expression in human pancreatic cancer and growth inhibition by Angiotensin type 1 receptor antagonist. FEBS Letters. 2001, 495: 197-200. 10.1016/S0014-5793(01)02377-8.PubMedView ArticleGoogle Scholar
- Goldfarb A, Diz I, Tubbs R, Ferrario M, Novick C: Angiotensin II receptor subtypes in the human renal cortex and renal cell carcinoma. J Urol. 1994, 151 (1): 208-13.PubMedGoogle Scholar
- Takeda H, Kondo S: Differences between Squamous Cell Carcinoma and Keratoacanthoma in Angiotensin Type-1 Receptor Expression. American Journal of Pathology. 2001, 158: 1633-1637.PubMedPubMed CentralView ArticleGoogle Scholar
- Marsigliante S, Resta L, Muscella A, Vinson GP, Marzullo A, Storelli C: AT1 antagonist II receptor subtype in the human larynx and squamous laryngeal carcinoma. Cancer Letters. 1996, 110: 19-27. 10.1016/S0304-3835(96)04449-7.PubMedView ArticleGoogle Scholar
- Batra V, Gropalakrish V, McNeill J, Hickie R: Angiotensin II elevates cytosolic free calcium in human lung adenocarcinoma cells via activation of AT1 receptors. J Urol. 1994, 151: 208-213.Google Scholar
- Dana K, Blanka Z, Eva S, Vlasta S: Int J Mol Med. 1998, 593-595.Google Scholar
- Hanahan D, Weinberg RA: The Hallmarks of Cancer. Cell. 2000, 100: 57-70. 10.1016/S0092-8674(00)81683-9.PubMedView ArticleGoogle Scholar
- Kawamata H, Furihata T, Omotehara F, Sakai T, Horiuchi H, Shinagawa Y, Imura J, Ohkura Y, Tachibana M, Kubota K, Terano A, Fujimori T: Identification of genes differentially expressed in a newly isolated human metastasizing esophageal cancer cell line, T.Tn-AT1, by cDNA microarray. Cancer Sci. 2003, 94: 699-706.PubMedView ArticleGoogle Scholar
- De Paepe, Verstraeten VLRM, De Potter CR, Vakaet LAML, Bullock GR: Growth stimulatory angiotensin II type-1 receptor is upregulated in breast hyperplasia and in situ carcinoma but not in invasive carcinoma. Histochem Cell Biol. 2001, 116: 247-254.View ArticleGoogle Scholar
- Mehta JL, Li D: Identification, Regulation and Function of a Novel Lectin-Like Oxidized Low-Density Lipoprotein Receptor. J Am Coll Cardiol. 2002, 39: 1429-1435. 10.1016/S0735-1097(02)01803-X.PubMedView ArticleGoogle Scholar
- Dechend R, Fiebler A, Lindschau C, Bischoff H, Muller D, Park JK, Dietz R, Haller H, Luft FC: Modulating Angiotensin II-Induced Inflammation by HMG Co-A Reductase Inhibition. Am J Hypertens. 2001, 14: 55S-61S. 10.1016/S0895-7061(01)02070-2.PubMedView ArticleGoogle Scholar
- Nagase M, Ando K, Nagase T, Kaname S, Sawamura T, Fuj T: Redox-Sensitive Regulation of LOX-1 Gene Expression in Vascular Endothelium. Biochemical and Biophysical Research Communications. 2001, 281: 720-725. 10.1006/bbrc.2001.4374.PubMedView ArticleGoogle Scholar
- Chan WP, Fung ML, Nobiling R, Leung PS: Activation of local renin-angiotensin system by chronic hypoxia in rat pancreas. Molecular and Cellular Endocrinology. 2000, 160: 107-114. 10.1016/S0303-7207(99)00258-0.PubMedView ArticleGoogle Scholar
- Leung PS, Fung ML, Tam MS: Renin-angiotensin system in the carotid body. Int J Biochem Cell Biol. 2003, 35: 847-854. 10.1016/S1357-2725(02)00180-2.PubMedView ArticleGoogle Scholar
- Chassagne C, Eddahibi S, Adamy C, Rideau D, Marcotte F, Dubois-Rande JL, Adnot S, Samuel JL, Teiger E: Modulation of Angiotensin II Receptor Expression during Development and Regression of Hypoxic Pulmonary Hypertension. Am J Respir Cell Mol Biol. 2000, 22: 323-332.PubMedView ArticleGoogle Scholar
- Grammatopoulos T, Morris K, Ferguson P, Weyhenmeyer J: Angiotensin protects cortical neurons from hypoxia-induced apoptosis via the angiotensin type 2 receptor. Molecular Brain Research. 2002, 99: 144-124. 10.1016/S0169-328X(02)00101-8.View ArticleGoogle Scholar
- Page EL, Robitaille GA, Pouyssegur , Richard DE: Induction of Hypoxia-Inducible Factor-1α by Transcriptional and Translation Mechanisms. JBC. 2002, 277: 48403-48409. 10.1074/jbc.M209114200.View ArticleGoogle Scholar
- Brown NS, Bicknell R: Hypoxia and oxidative stress in breast cancer. Oxidative stress: its effects on the growth, metastatic potential and response to therapy of breast cancer. Breast Cancer Res. 2001, 3: 323-327. 10.1186/bcr315.PubMedPubMed CentralView ArticleGoogle Scholar
- Maluccio M, Sharma V, Lagman M, Konijn G, Suthanthiran M: Angiotensin II Receptor Blockade: A novel Strategy to Prevent Immunosuppressant-Associated cancer Progression. Transplantation Proceedings. 2001, 33: 1820-1821. 10.1016/S0041-1345(00)02696-8.PubMedView ArticleGoogle Scholar
- Lever AF, Hole DJ, Gillis CR, McCallum IR, McInnes GT, MacKinnon PL, Meredith PA, Murray LS, Reid JL, Robertson JWK: Do inhibitors of angiotensin-1-converting enzyme protect against risk of cancer?. Lancet. 1998, 352: 179-184. 10.1016/S0140-6736(98)03228-0.PubMedView ArticleGoogle Scholar
- Miyajima A, Kosaka T, Asano T, Asano T, Seta K, Kawai T, Hayakawa M: Angiotensin II Type I Antagonist Prevents Pulmonary Metastasis of Murine Renal Cancer by Inhibiting Tumor Angiogenesis. Cancer research. 2002, 62: 4176-4179.PubMedGoogle Scholar
- Egami K, Murohara T, Shimada T, Sasaki KI, Shintani S, Sugaya T, Ishii M, Akagi T, Ikeda H, Matsuishi T, Imaizumi T: Role of host angiotensin II type I receptor in tumor angiogenesis and growth. J Clin Invest. 2003, 112: 67-75. 10.1172/JCI200316645.PubMedPubMed CentralView ArticleGoogle Scholar
- Yu Q, Stamenkovic I: Cell surface-localised matrix metalloproteinase-9 proteolytically activates TGF-β and promotes tumor invasion and angiogenesis. Genes & Development. 2000, 14: 163-176.Google Scholar
- Jin D, Takai S, Shiota N, Miyazaki M: Tranilast, an anti-allergic drug, possesses antagonistic potency to angiotensin II. European Journal of Pharmacology. 1998, 361: 199-205. 10.1016/S0014-2999(98)00740-7.PubMedView ArticleGoogle Scholar
- Yashiro M, Chung Y, Sowa M: Tranilast [N-(3,4 dimethoxycinnamoyl) anthranilic acid] down regulates the growth of scirrhous gastric cancer. Anticancer Res. 1997, 17: 895-900.PubMedGoogle Scholar
- Noguchi N, Kawashiri S, Tanaka A, Kato K, Nakaya H: Effects of fibroblast growth inhibitor on proliferation and metastasis of oral squamous cell carcinoma. Oral Oncology. 2003, 39: 240-247. 10.1016/S1368-8375(02)00092-1.PubMedView ArticleGoogle Scholar
- Platten M, Wild-Bode C, Wick W, Leitlein J, Dichgans J, Weller M: [N-(3,4-dimethoxycinnamoyl) anthranilic acid] (Tranilast) inhibits transforming growth factor-beta release and reduces migration and invasiveness of human malignant glioma cells. Int J Cancer. 2001, 93: 53-61. 10.1002/ijc.1289.PubMedView ArticleGoogle Scholar
- Hiroi M, Onda M, Uchida E, Aimoto T: Anti-tumor Effect of [N-(3,4-dimethoxycinnamoyl) anthranilic acid] (tranilast) on Experimental Pancreatic Cancer. J Nippon Med Sch. 2002, 69: 224-234. 10.1272/jnms.69.224.PubMedView ArticleGoogle Scholar
- Shime H, Kariya M, Orii A, Momma C, Kanamori T, Fukuhara K, Musakari T, Tsuruta Y, Takakura K, Nikaido T, Fujii S: Tranilast inhibits the proliferation of uterine leiomyoma cells vitro through G1 arrest associated with the induction of p21 (waf1) and p53. J Clin Endocrinol Metab. 2002, 87: 5610-5617. 10.1210/jc.2002-020444.PubMedView ArticleGoogle Scholar
- Abali H, Gullu IH, Engin H, Haznedaroglu IC, Erman M, Tekuzman G: Old antihypertensives as novel antineoplastics: angiotensin-I-converting enzyme inhibitors and angiotensin II type 1 receptor antagonists. Medical Hypotheses. 2002, 59: 344-348. 10.1016/S0306-9877(02)00185-8.PubMedView ArticleGoogle Scholar
- Uemura H, Ishiguro H, Nakaigawa N, Nagashima Y, Miyoshi Y, Fujinami K, Sakaguchi A, Kubota Y: Angiotensin II receptor blocker shows antiproliferative activity in prostate cancer cells: A possibility of tyrosine kinase inhibitor of growth factor. Molecular Cancer Therapeutics. 2003, 2 (11): 1139-1147.PubMedGoogle Scholar
- Tucker CE, Chen LS, Judkins MB, Farmer JA, Gill SC, Drolet DW: Detection and plasma pharmacokinetics of an anti-vascular endothelial growth factor oligonucleotide-aptamer (NX1838) in rhesus monkeys. Journal of Chromatography B. 1999, 732 (1): 203-212. 10.1016/S0378-4347(99)00285-6.View ArticleGoogle Scholar
- Yoshiji H, Yoshii J, Ikenaka Y, Noguchi R, Yanase K, Tsujinoue H, Imazu H, Fukui H: Suppression of the renin-angiotensin system attenuates vascular endothelial growth factor-mediated tumor development and angiogenesis in murine hepatocellular carcinoma cells. Int J Oncol. 2002, 20: 1227-1231.PubMedGoogle Scholar
- Yoshiji H, Kuriyama S, Kawata M, Yoshii J, Ikenaka Y, Noguchi R, Nakatani T, Tsujinoue H, Fukui H: The angiotensin-I-converting enzyme inhibitor perindopril suppresses tumor growth and angiogenesis: Possible role of the vascular endothelial growth factor. Clinical Cancer Research. 2001, 7: 1073-1078.PubMedGoogle Scholar
- Szlosarek PW, Balkwill FR: Tumour necrosis factor α: a potential target for the therapy of solid tumours. The Lancet oncol. 2003, 4: 565-573. 10.1016/S1470-2045(03)01196-3.PubMedView ArticleGoogle Scholar
- Apte RN, Voronov E: Interleukin-1, a major pleiotropic cytokine in tumor-host interactions. Seminars in Cancer Biology. 2002, 12: 277-290. 10.1016/S1044-579X(02)00014-7.PubMedView ArticleGoogle Scholar
- Kobie JJ, Akporiaye ET: Immunosuppressive role of transforming growth factor beta in breast cancer. Clinical and Applied Immunology Reviews. 2003, 3: 277-287.View ArticleGoogle Scholar
- Adam JK, Odhav B, Bhoola KD: Immune responses in cancer. Pharmacology & Therapeutics. 2003, 99: 113-132. 10.1016/S0163-7258(03)00056-1.View ArticleGoogle Scholar
- Eto H, Biro S, Miyata M, Kaieda H, Obata H, Kihara K, Tei C: Angiotensin II type 1 receptor participates in extracellular matrix production in the late stage of remodelling after vascular injury. Cardiovascular research. 2003, 59: 200-211. 10.1016/S0008-6363(03)00356-0.PubMedView ArticleGoogle Scholar
- Kwang KK, Jeong YA, Sueng HH, Dae SK, Dong KJ, Hyung SK, Mi-Seung S, Ta HA, In SC, Eak KS: Pleiotropic Effects of Angiotensin II receptor blockade in Hypertensive Patients. J Am Coll of Cardiol. 2003, 42: 905-910. 10.1016/S0735-1097(03)00846-5.View ArticleGoogle Scholar
- Saiura A, Sata M, Hirata Y, Nagai R, Makuuchi M: Tranilast inhibits transplant-associated coronary arteriosclerosis in a murine model of cardiac transplantation. European Journal of Pharmacology. 2001, 433: 163-168. 10.1016/S0014-2999(01)01501-1.PubMedView ArticleGoogle Scholar
- Costanzo A, Moretti F, Burgio VL, Bravi C, Guido F, Levrero M, Puri PL: Endothelial activation by angiotensin II through NfkappaB and P38 pathways: Involvement of NfkappaB-inducible kinase (NIK), free oxygen radicals, and selective inhibition by aspirin. J Cell Physiol. 2003, 195: 402-410. 10.1002/jcp.10191.PubMedView ArticleGoogle Scholar
- Takemori K, Ito H, Suzuki T: Effects of the AT1 Receptor Antagonist on Adhesion Molecule Expression in Leukocytes and Brain Microvessels of Stoke-Prone Spontaneously Hypertensive Rats. Am J Hypertens. 2000, 13: 1233-1241. 10.1016/S0895-7061(00)01202-4.PubMedView ArticleGoogle Scholar
- Wassmann S, Hilgers S, Laufs U, Bohm M, Nickenig G: Angiotensin II type 1 receptor antagonism improves hypercholesterolemia-associated endothelial dysfunction. Arteriosclerosis, Thrombosis and Vascular Biology. 2002, 22: 1208-10.1161/01.ATV.0000022847.38083.B6.View ArticleGoogle Scholar
- Franscini LMD, Vigier ROV, Pfister R, Casaulta-Aebischer C, Fossali E, Bianchetti MG: Effectiveness and Safety of the Angiotensin II Antagonist Irbesartan in Children With Chronic Kidney Diseases. Am J Hypertens. 2002, 15: 1057-1063. 10.1016/S0895-7061(02)03083-2.PubMedView ArticleGoogle Scholar
- Tsang SW, Ip SP, Leung PS: Prophylactic and therapeutic treatments with AT1 and AT2 receptor antagonists and their effects on changes in the severity of pancreatitis. IJBCB. 2004, 36: 330-339. 10.1016/S1357-2725(03)00257-7.Google Scholar
- Stander H, Stadelmann , Luger T, Traupe H: Granulomatous blephartis successfully treated with Tranilast,. Br J Dermatol. 2003, 149: 222-224. 10.1046/j.1365-2133.2003.05424.x.View ArticleGoogle Scholar
- Perez-Castrillon JL, Silvia J, Justo I, Sanz A, Martin-Luquero M, Igea R, Escudero P, Pueyo C, Diaz C, Hernandez G, Duenas A: Effect of Quinapril, Quinapril-Hydroclorothiazide, and Enalapril on the Bone Mass of Hypertensive Subjects: Relationship with Angiotensin Converting Enzyme Polymorphisms. Am J Hypertens. 2003, 16: 453-459. 10.1016/S0895-7061(03)00845-8.PubMedView ArticleGoogle Scholar
- Burton T, Liang B, Dibrov A, Amara F: Transforming growth factor-β-induced transcription of the Alzheimer β-amyloid precursor proteingene involves interaction between the CTCF-complex and Smads. Biochemical and Biophysical Research Communications. 2002, 295: 713-723. 10.1016/S0006-291X(02)00725-8.PubMedView ArticleGoogle Scholar
- Ge J, Barnes NM: Alterations in angiotensin AT1 and AT2 receptor subtype levels in brain regions from patients with neurodegenerative disorders. European Journal of Pharmacology. 1996, 297: 299-306. 10.1016/0014-2999(95)00762-8.PubMedView ArticleGoogle Scholar
- Savaskan E, Hock C, Olivieri G, Bruttel S, Rosenberg C, Hulette C, Muller-Spahn F: Cortical alterations of angiotensin converting enzyme, angiotensin II and AT1 receptor in Alzheimer's disease. Neurobiology of Aging. 2001, 22: 541-546. 10.1016/S0197-4580(00)00259-1.PubMedView ArticleGoogle Scholar
- Platten M, Eitel K, Wischhusen J, Dichgans J, Weller M: Involvement of protein kinase Cδ and extracellular signal-regulated kinase-2 in the suppression of microglial inducible nitric oxide synthase expression by [N-(3,4-dimethoxycinnamoyl) anthranilic acid] (Tranilast). Biochemical Pharmacology. 2003, 66: 1263-1270. 10.1016/S0006-2952(03)00449-0.PubMedView ArticleGoogle Scholar
- Tamura M, Chen YJ, Howard EF, Tanner M, Landon EJ, Myers PR: Lipopolysaccharides and cytokines downregulate the angiotensin II type 2 receptor in rat cardiac fibroblasts. European Journal of Pharmacology. 1999, 386: 289-295. 10.1016/S0014-2999(99)00755-4.PubMedView ArticleGoogle Scholar
- Li JY, Avallet O, Berthelon MC, Langlois D, Saez JM: Effects of growth factors on cell proliferation and angiotensin II type 2 receptor number and mRNA in PC12W and R3T3 cells. Molecular and Cellular Endocrinology. 1998, 139: 61-69. 10.1016/S0303-7207(98)00074-4.PubMedView ArticleGoogle Scholar
- Heemskerk VH, Daemen MARC, Buurman WA: Insulin-like growth factor (IGF-1) and growth hormone (GH) in immunity and inflammation. Cytokine & Growth Factor Reviews. 1999, 10: 5-14. 10.1016/S1359-6101(98)00022-7.View ArticleGoogle Scholar
- Khan AS, Sane DC, Wannenburg T, Sonntag WE: Growth hormone, insulin-like growth factor-1 and the aging cardiovascular system. Cardiovascular Research. 2002, 54: 25-35. 10.1016/S0008-6363(01)00533-8.PubMedView ArticleGoogle Scholar
- Katsanos KH, Tsatsoulis A, Christodoulou D, Challa A, Katsaraki A, Tsianos EV: Reduced serum insulin-like growth factor-1 (IGF-1) and IGF-binding protein-3 levels in adults with inflammatory bowel disease. Growth Hormone & IGF Research. 2001, 11: 364-367. 10.1054/ghir.2001.0248.View ArticleGoogle Scholar
- Humbert S, Saudou F: Huntingtin phosphorylation and signaling pathways that regulate toxicity in Huntington's disease. Clinical Neuroscience Research. 2003, 3: 149-155. 10.1016/S1566-2772(03)00057-4.View ArticleGoogle Scholar
- Gasparini L, Xu H: Potential roles of insulin and IGF-1 in Alzheimer's disease. Trends in Neurosciences. 2003, 28: 404-406. 10.1016/S0166-2236(03)00163-2.View ArticleGoogle Scholar
- Offen D, Shtaif B, Hadad D, Weizman A, Melamed E, Gil-Ad I: Protective effect of insulin-like-growth-factor-1 against dopamine-induced neurotoxicity in human and rodent neuronal cultures: possible implications for Parkinson's disease. Neuroscience Letters. 2001, 316: 129-132. 10.1016/S0304-3940(01)02344-8.PubMedView ArticleGoogle Scholar
- Schulze PC, Gielen S, Schuler G, Hambrecht R: Chronic heart failure and skeletal muscle catabolism: effects of exercise training. International Journal of Cardiology. 2002, 85: 141-149. 10.1016/S0167-5273(02)00243-7.PubMedView ArticleGoogle Scholar
This article is published under license to BioMed Central Ltd. This is an open-access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.