Differential Effects of Doxazosin on Renin-Angiotensin-System- Regulating Aminopeptidase Activities in Neuroblastoma and Glioma Tumoral Cells

2019 ◽  
Vol 18 (1) ◽  
pp. 29-36 ◽  
Author(s):  
María Jesús Ramírez-Expósito ◽  
José Manuel Martínez-Martos

Background: It has been described that doxazosin, an antihypertensive drug, also promotes glioblastoma cells death by inhibiting cell proliferation, arresting cell cycle and inducing apoptosis. Doxazosin has also demonstrated several modulator effects on renin-angiotensin system (RAS)- regulating aminopeptidase activities, which are highly involved in tumor growth in experimental glioma. Therefore, it remains to elucidate if the anti-tumoral effects of doxazosin could also be mediated by the proteolytic regulatory components of the RAS. Objective: To analyze the effects of doxazosin on cell growth and on RAS-regulating proteolytic regulatory aspartyl aminopeptidase (ASAP), aminopeptidase A (APA), aminopeptidase N (APN), aminopeptidase B (APB) and insulin-regulated aminopeptidase (IRAP) specific activities in the human neuroblastoma NB69 and astroglioma U373-MG tumoral cell lines. Methods: Human neuroblastoma NB69 and astroglioma U373-MG cell lines were treated with doxazosin 50-500 μM for 24h or 48h. The effects on cell growth and on RAS-regulating aminopeptidase specific activities were analyzed. Results: Doxazosin treatments promote a concentration-dependent inhibition on cell growth in both NB69 and U373-MG cells, being NB69 cells more sensitive to the drug than U373-MG cells. However, its effects on RAS-regulating aminopeptidase specific activities depend on the concentration used, the duration of the treatment and the cell type. These data confirm the existence of a different dynamic progression of RAS cascade in each tumoral cell line as a consequence of the treatment with doxazosin and time of action, which also implies a very dynamic metabolism of the peptides which participate in each step of RAS cascade. Conclusion: Our results indicate that doxazosin modifies the proteolytic regulatory enzymes of RAS cascade, modulating the bioactive efficacy of the different angiotensin peptides, and therefore, of their functional roles as initiators/promoters of cell proliferation as autocrine/paracrine mediators.

Cancers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1457 ◽  
Author(s):  
Maria Joana Catarata ◽  
Ricardo Ribeiro ◽  
Maria José Oliveira ◽  
Carlos Robalo Cordeiro ◽  
Rui Medeiros

The mechanistic involvement of the renin-angiotensin system (RAS) reaches beyond cardiovascular physiopathology. Recent knowledge pinpoints a pleiotropic role for this system, particularly in the lung, and mainly through locally regulated alternative molecules and secondary pathways. Angiotensin peptides play a role in cell proliferation, immunoinflammatory response, hypoxia and angiogenesis, which are critical biological processes in lung cancer. This manuscript reviews the literature supporting a role for the renin-angiotensin system in the lung tumor microenvironment and discusses whether blockade of this pathway in clinical settings may serve as an adjuvant therapy in lung cancer.


Hypertension ◽  
2012 ◽  
Vol 60 (suppl_1) ◽  
Author(s):  
Julia M Carlson ◽  
John J Gildea ◽  
Helen E McGrath ◽  
Robin A Felder

SLC4A5 is a sodium-bicarbonate co-transporter involved with sodium homeostasis. Based on unpublished data, two SLC4A5 single nucleotide polymorphisms (SNPs rs1017783 and rs7571842) have been highly associated with an individual’s salt-sensitivity status. Since the renal proximal tubule (RPT) regulates a large percentage of renal sodium transport, we investigated whether SLC4A5 was present in this nephron segment. Using confocal immunofluorescence microscopy, we found expression of SLC4A5 in human RPT cell plasma membrane and intracellular membrane vesicles. We then examined the physiologic implications of the SLC4A5 SNPs in human RPT cells. Using immunoblotting and RT-PCR, we found no significant differences in basal SLC4A5 expression in RPT cells between individuals that are homozygous variant at both SNPs and individuals that are wild-type (WT) for both alleles. Stimulation of the dopaminergic system with 1μM fenoldopam, or the renin-angiotensin system with 10 nM angiotensin II or 10 nM angiotensin III (n=18 per treatment) over 3 and 24 hours did not significantly alter SLC4A5 protein or 24 hour mRNA expression. These data indicate that SLC4A5 is not directly regulated by either the renal dopaminergic or renin-angiotensin system. However, 24 hour stimulation with the sodium ionophore monensin (MON, 1μM) significantly increased overall mRNA expression of SLC4A5 by 182±0.098% over vehicle (VEH) (ΔCq VEH=0.283±0.035; n=18, p<0.001). There was also a significant increase in SLC4A5 mRNA in three cell lines homozygous variant for both alleles compared to three WT cell lines following MON treatment at both 3 hours (138±0.10%; ΔCq WT MON = 0.5±0.052; n=9, p<0.05) and 24 hours (161±0.11%; ΔCq WT MON = 0.39±0.066; n=9, p<0.02). Three but not 24 hour stimulation with MON also significantly increased overall expression of SLC4A5 protein (137±0.00041%; RFU VEH=0.0030±0.00022; n=18, p<0.01). MON, by allowing salt to enter a cell, may be activating an enhancer that leads to increased transcription of SLC4A5 mRNA that is more effective in homozygous variant cell lines. These novel observations demonstrate that SNPs located in a non-promoter DNA intron are associated with enhanced promoter activity that is regulated by altered intracellular sodium.


2020 ◽  
Vol 71 (6) ◽  
pp. 307-311
Author(s):  
Sorin Ungurianu ◽  
Constantin Trus ◽  
Roxana-Rosmary Enciu

It is already known from a variety of previous reports that an independent brain renin�angiotensin system (RAS) exists, completely separated from the one in the periphery. This independent brain RAS has all the precursors and the enzymatic structures necessary for the generation of the angiotensin peptides. Thus, in the last few years various groups started focusing on the more central effects of less known angiotensins (e.g in comparison with Angiotensin (Ang) II), namely Ang III, Ang IV, Ang-(1�7) or Ang 5-8. One of these newly emerging angiotensins which has become an increased center of interest in many studies is Ang-(1-7), which is a heptapeptide previously described especially for its opposite effects to Ang II, in the peripheral vascular area, but also described for some opposite central functions vs. Ang II. These aspects are completed with the fact that it was recently suggested that the renin�angiotensin system could modulate the oxidative stress metabolism, and also it seems that the manifestations of Angiotensin-(1-7) on the basal oxidative stress status are contradictory, with a variety of reports describing controversial (e.g. both pro-oxidant and antioxidant actions) effects for this heptapeptide. Our results presented here are confirming a possible antioxidant effect of Ang-(1�7) administration on rat, as shown by the increased levels of antioxidant enzymes from the temporal lobe (superoxide dismutase and glutathione peroxidase) and decreased levels of malondialdehyde, as an important lipid peroxidation parameter.


2014 ◽  
Vol 138 ◽  
pp. 56-63 ◽  
Author(s):  
María Jesús Ramírez-Expósito ◽  
María Dolores Mayas-Torres ◽  
María Pilar Carrera-González ◽  
Sonia B. Jiménez-Pulido ◽  
Nuria A. Illán-Cabeza ◽  
...  

2021 ◽  
Author(s):  
Matthew Munro

Colorectal cancer (CRC) is the third most common cancer and the second highest cause of cancer deaths globally. More than 70% of CRC-related deaths are due to metastasis to the liver. The cancer stem cell (CSC) concept hypothesises that CSCs drive tumour growth, chemoresistance, recurrence and metastasis. Markers such as CD133, LGR5 and EpCAM, have been used to identify and isolate CSCs in CRC. However, these markers are often expressed by cells with no stem cell properties and are not expressed by all tumour-initiating cells. An improved range of markers to define CSCs is needed. In 2007, adult mouse and human fibroblasts were reprogrammed into a stem cell state and defined as induced pluripotent stem cells (iPSCs) using transcription factors OCT4, SOX2, NANOG, KLF4 and c-MYC. These genes have well-documented roles in embryonic development and the maintenance of pluripotency, and their expression has been investigated in a range of cancers. <br><br>The renin-angiotensin system (RAS) physiologically maintains blood pressure and volume and is also acknowledged to play a role in cancer. Over-expression of (pro)renin receptor (PRR), angiotensin II type 1 receptor (AT1R) and type 2 receptor (AT2R), and angiotensin-converting enzyme (ACE) have been reported in cancer. Epidemiological studies investigating the effect of RAS inhibitors on cancer outcomes have shown contradictory results.<br><br>This thesis investigates the expression of iPSC markers and RAS components in colon adenocarcinoma (CA) with three specific aims: (1) to compare CA-derived primary cell lines to their original CA tissues; (2) to investigate the expression profiles of iPSC markers in CA; and (3) to investigate expression of RAS components by CA CSCs and to determine whether CSCs can be targeted by RAS modulators. <br><br>DNA sequencing was carried out to compare the mutational profiles of formalin-fixed paraffin-embedded (FFPE) CA tissues and CA-derived cell lines to confirm whether the cell lines were a suitable in vitro model for the parent tumours.<br><br><div>Proteomics was performed to determine proteomic differences between CA tissues and patient-matched normal colon (NC) tissues, CA-derived cell lines and NC-derived cells, and between low grade CA (LGCA) tissues and cell lines and high grade CA (HGCA) tissues and cell lines. Biological processes which may link the RAS and CA were investigated, revealing enrichment of various signalling pathways that may play roles in CA onset and progression directly or via the RAS.</div><div><br></div>Western blotting and immunohistochemical staining showed elevated protein levels of OCT4, SOX2, NANOG, c-MYC, AT2R, PRR and cathepsin D in CA tissues relative to their patient-matched NC tissues, with SOX2, ACE and cathepsin B at similar levels and KLF4 less abundant in CA compared with NC tissues. Co-expression analysis by immunofluorescence staining showed a small number of epithelial cells co-expressed NANOG, SOX2, KLF4, c-MYC and CD133, as well as PRR, ACE2 and AT2R, while a small number of stromal cells co-expressed OCT4 and AT2R. This indicates the presence of at least one CSC subpopulation in CA, which expresses RAS components. HGCA tissue-derived cell lines expressed higher levels of OCT4 and SOX2 than LGCA-derived cell lines. The primary cell lines were sorted based on EpCAM expression. These EpCAM High and EpCAM Low cell subpopulations could undergo directed differentiation down the three embryonic lineages. A small number of CA-derived cells, particularly within the HGCA-derived cells, formed tumourspheres. Treatment of HGCA-derived cell lines with RAS modulators revealed that β-blockers and AT2R antagonists consistently reduced their metabolism, tumoursphere formation and iPSC marker expression. <br><br>The findings of this thesis suggest that CA-derived cell lines expressing iPSC markers have stem cell function and express RAS components. Furthermore, RAS modulators may directly influence CSCs in CA by reducing iPSC marker gene expression. This indicates a potential role for RAS modulators in regulating CSCs, which merits further investigation.


2019 ◽  
Vol 316 (5) ◽  
pp. H958-H970 ◽  
Author(s):  
Robson Augusto Souza Santos ◽  
Gavin Y. Oudit ◽  
Thiago Verano-Braga ◽  
Giovanni Canta ◽  
Ulrike Muscha Steckelings ◽  
...  

Thirty years ago, a novel axis of the renin-angiotensin system (RAS) was unveiled by the discovery of angiotensin-(1−7) [ANG-(1−7)] generation in vivo. Later, angiotensin-converting enzyme 2 (ACE2) was shown to be the main mediator of this reaction, and Mas was found to be the receptor for the heptapeptide. The functional analysis of this novel axis of the RAS that followed its discovery revealed numerous protective actions in particular for cardiovascular diseases. In parallel, similar protective actions were also described for one of the two receptors of ANG II, the ANG II type 2 receptor (AT2R), in contrast to the other, the ANG II type 1 receptor (AT1R), which mediates deleterious actions of this peptide, e.g., in the setting of cardiovascular disease. Very recently, another branch of the RAS was discovered, based on angiotensin peptides in which the amino-terminal aspartate was replaced by alanine, the alatensins. Ala-ANG-(1−7) or alamandine was shown to interact with Mas-related G protein-coupled receptor D, and the first functional data indicated that this peptide also exerts protective effects in the cardiovascular system. This review summarizes the presentations given at the International Union of Physiological Sciences Congress in Rio de Janeiro, Brazil, in 2017, during the symposium entitled “The Renin-Angiotensin System: Going Beyond the Classical Paradigms,” in which the signaling and physiological actions of ANG-(1−7), ACE2, AT2R, and alatensins were reported (with a focus on noncentral nervous system-related tissues) and the therapeutic opportunities based on these findings were discussed.


2000 ◽  
Vol 4 (1) ◽  
pp. 67-73 ◽  
Author(s):  
GARY PRESCOTT ◽  
DAVID W. SILVERSIDES ◽  
SUI MEI LINDA CHIU ◽  
TIMOTHY L. REUDELHUBER

The activity of a local cardiac renin-angiotensin system (RAS) has long been suspected in the promotion of cardiac pathologies including hypertrophy, ischemia, and infarction. All of the components of the RAS cascade have been demonstrated to be synthesized within the heart with the possible exception of the first enzyme in the cascade, renin. In the current study, we provide direct evidence that circulating renin can contribute to cardiac-specific synthesis of angiotensin peptides. Furthermore, we demonstrate this effect is independent of blood pressure and that in animals of comparable blood pressure, elevated circulating renin significantly enhances cardiac fibrosis. These results may serve to explain some of the cardiac pathologies associated with the RAS.


2016 ◽  
Vol 310 (2) ◽  
pp. H137-H152 ◽  
Author(s):  
Mark C. Chappell

The renin-angiotensin system (RAS) constitutes a key hormonal system in the physiological regulation of blood pressure through peripheral and central mechanisms. Indeed, dysregulation of the RAS is considered a major factor in the development of cardiovascular pathologies, and pharmacological blockade of this system by the inhibition of angiotensin-converting enzyme (ACE) or antagonism of the angiotensin type 1 receptor (AT1R) offers an effective therapeutic regimen. The RAS is now defined as a system composed of different angiotensin peptides with diverse biological actions mediated by distinct receptor subtypes. The classic RAS comprises the ACE-ANG II-AT1R axis that promotes vasoconstriction; water intake; sodium retention; and increased oxidative stress, fibrosis, cellular growth, and inflammation. In contrast, the nonclassical RAS composed primarily of the ANG II/ANG III-AT2R and the ACE2-ANG-(1–7)-AT7R pathways generally opposes the actions of a stimulated ANG II-AT1R axis. In lieu of the complex and multifunctional aspects of this system, as well as increased concerns on the reproducibility among laboratories, a critical assessment is provided on the current biochemical approaches to characterize and define the various components that ultimately reflect the status of the RAS.


Hypertension ◽  
2012 ◽  
Vol 60 (suppl_1) ◽  
Author(s):  
Marko Poglitsch ◽  
Cornelia Schwager ◽  
Oliver Domenig ◽  
Dunja van Oyen ◽  
Manfred Schuster ◽  
...  

The Renin-Angiotensin-System (RAS) is critically involved in the regulation of important physiological functions including blood pressure and fluid balance. It is constituted by multiple enzymes giving rise to a meshwork of effector peptides, which mediate their functions through binding to specific receptor molecules. Therefore, the modification of angiotensin peptide levels represents a common strategy for the treatment of RAS-associated diseases and is frequently achieved by the pharmacologic regulation of enzymes taking part in angiotensin metabolism. We developed a highly sensitive method, which allows the simultaneous absolute quantification of up to 10 different angiotensin peptides in human plasma and whole blood (RAS-Fingerprinting). The measurement of RAS-Fingerprints provides unique insights into the physiology of the human RAS and therefore represents a powerful tool for the patient specific evaluation of this physiologically important peptide hormone system. Beside the precise quantification of angiotensin peptides in plasma and whole blood, RAS-Fingerprints analyze the biochemical hardware of the RAS at a previously unachieved level of detail and accuracy. During the development and validation of our LC-MS/MS based method, comprehensive datasets showing multiple applications for RAS-Fingerprinting have been generated. Investigation of healthy volunteers revealed that a patient specific state of the RAS exists, which is defined by a unique composition of RAS enzyme activities that might have crucial effects on the outcome of RAS targeted therapies in individual patients. RAS-Fingerprinting in healthy volunteers treated with an Angiotensin-Receptor-Blockers, ACE-Inhibitor or Renin-Inhibitor revealed that the human RAS reacts to different drugs in a very dynamic and specific way. Therefore, RAS-Fingerprinting could contribute to the development of innovative therapeutic approaches affecting the RAS. The implementation of RAS-Fingerprinting into clinical studies would substantially enhance our understanding of the human RAS and could lead to the development of personalized treatment schemes in the management of RAS-associated diseases in the near future.


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