Angiotensin II facilitates breast cancer cell migration and metastasis

Beyond blood pressure, fluid and electrolyte homeostasis - Role of the renin angiotensin aldosterone system in the interplay between metabolic diseases and breast cancer

The classical renin angiotensin aldosterone system (RAAS), as well as the recently described counter-regulatory or non-canonical RAAS have been well characterized for their role in cardiovascular homeostasis. Moreover, extensive research has been conducted over the past decades on both paracrine and the endocrine roles of local RAAS in various metabolic regulations and in chronic diseases. Clinical evidence from patients on RAAS blockers as well as pre-clinical studies using rodent models of genetic manipulations of RAAS genes documented that this system may play important roles in the interplay between metabolic diseases and cancer, namely breast cancer. Some of these studies suggest potential therapeutic applications and repurposing of RAAS inhibitors for these diseases. In this review, we discuss the mechanisms by which RAAS is involved in the pathogenesis of metabolic diseases such as obesity and type-2 diabetes as well as the role of this system in the initiation, expansion and/or progression of breast cancer, especially in the context of metabolic diseases.

Preparation, Radiolabeling with 68Ga/177Lu and Preclinical Evaluation of Novel Angiotensin Peptide Analog: A New Class of Peptides for Breast Cancer Targeting

AIM

Angiotensin II (AngII) is known to play a significant part in the development of breast cancer by triggering cell propagation of breast cancer, tumor angiogenesis, and regulating tumor invasion and cell migration. AngII arbitrates its action via two G-protein-coupled receptors, AngII type 1 receptor (AT1) and AngII type 2 receptor (AT2). Overexpression of the AT1 receptor in breast cancer cells seems to promote tumor growth and angiogenesis, thus targeting the AT1 receptor using AngII peptide would facilitate the detection of breast carcinoma. We developed an AngII peptide intending to assess whether the peptide of the renin-angiotensin system holds the ability to target AT1 receptor-overexpressing breast cancer in vivo.

METHODS

DOTA-coupled AngII peptide was synthesized by conventional solid-phase peptide synthesis according to Fmoc/HATU chemistry. 68Ga/177Lu labeled AngII peptide was evaluated for its binding with TNBC MDA-MB-231 and ER+ MCF7 cell lines. Pharmacokinetics was studied in healthy balb/c mice and in vivo tumor targeting in nude mice with MDA-MB-231 tumors xenografts.

RESULTS

DOTA-AngII peptide was labeled efficiently with 68Ga/177Lu with high labeling efficiency (≥90%). The stability of the radiopeptide in human plasma was found to be high. The AngII peptide analog showed nanomolar (<40 nM) AT1 receptor-specific binding affinity. The radioactivity internalized into MDA-MBA-231 and MCF7 cells were 14.97% and 11.75%, respectively. In vivo, biodistribution in balb/c mice exhibited efficient clearance of 68Ga/177Lu-DOTA-AngII peptide from the blood and elimination predominantly by the renal system due to its hydrophilic nature. A low amount of radioactivity was seen in the major organs including lungs, liver, stomach, spleen, and intestines (<3% ID/g) except the kidneys. A high renal-urinary excretion was observed for the radiotracer. In the TNBC MDA-MB-231 xenografts model, radiolabeled AngII peptide exhibited specific and effective AT1-based targeting in vivo. A rapid and efficient tumor targeting (2.18% ID/g at 45 min p.i.) together with fast renal excretion (~67% ID) highlights the tumor-targeting potential of the radiotracer. The AT1 receptor specificity of the radiotracer was validated by blocking assays. Furthermore, PET imaging provided sufficient visualization of MDA-MB-231 tumors in nude mice.

CONCLUSION

Our findings suggest that 68Ga/177Lu-DOTA-AngII peptide can be useful for the theranostic application of breast carcinomas. This study suggests the potential of this innovative class of peptides for rapid and efficient targeting of tumors and warrants further evaluation.

The renin-angiotensin-aldosterone system (RAAS) signaling pathways and cancer: foes versus allies

The renin-angiotensin-aldosterone system (RAAS), is an old system with new fundamental roles in cancer biology which influences cell growth, migration, death, and metastasis. RAAS signaling enhances cell proliferation in malignancy directly and indirectly by affecting tumor cells and modulating angiogenesis. Cancer development may be influenced by the balance between the ACE/Ang II/AT1R and the ACE2/Ang 1-7/Mas receptor pathways. The interactions between Ang II/AT1R and Ang I/AT2R as well as Ang1-7/Mas and alamandine/MrgD receptors in the RAAS pathway can significantly impact the development of cancer. Ang I/AT2R, Ang1-7/Mas, and alamandine/MrgD interactions can have anticancer effects while Ang II/AT1R interactions can be involved in the development of cancer. Evidence suggests that inhibitors of the RAAS, which are conventionally used to treat cardiovascular diseases, may be beneficial in cancer therapies.Herein, we aim to provide a thorough description of the elements of RAAS and their molecular play in cancer. Alongside this, the role of RAAS components in sex-dependent cancers as well as GI cancers will be discussed with the hope of enlightening new venues for adjuvant cancer treatment.

The use of angiotensin system inhibitors correlates with longer survival in resected pancreatic adenocarcinoma patients

BACKGROUND

Activities and inhibition of the Renin-Angiotensin-Aldosterone System (RAAS) may affect the survival of resected pancreatic ductal adenocarcinoma (PDAC) patients METHOD: A single-institution retrospective analysis of resected PDAC patients between 2010 and 2019. To estimate the effect of angiotensin system inhibitors (ASIs) on patient survival, we performed Kaplan Meier analysis, Cox Proportional Hazards model, Propensity Score Matching (PSM), and inverse probability weighting (IPW) analysis.

RESULTS

742 patients were included in the analysis. The average age was 67.0 years, with a median follow-up of 24.1 months. The use of ASI was associated with significantly longer overall survival in univariate (p = 0.004) and multivariable (HR = 0.70 [0.56-0.88],p = 0.003) adjusted analysis. In a propensity score-matched cohort of 400 patients, ASI use was again associated with longer overall survival (p = 0.039). Lastly, inverse probability weighting (IPW) analysis suggested that the use of ASI was associated with an average treatment effect on the treated (ATT) of HR = 0.68 [0.53-0.86],p = 0.002) for overall survival.

CONCLUSION

In this single-institution retrospective study focusing on resected PDAC patients, the use of ASI was associated with longer overall survival in multiple statistical models. Prospective clinical trials are needed before routine clinical implementation of ASI as an adjuvant to existing therapy can be recommended.

Using publicly available datasets to identify population-based transcriptomic landscape contributing to the aggressiveness of breast cancer in young women

Introduction: Although the risk of breast cancer increases with advancing age, some regions have larger number of young breast cancer patients (≤45 years-old), such as the Middle East, Eastern Asia, and North Africa, with more aggressive and poorly differentiated tumors. We aimed to conduct an in-silico analysis in an attempt to understand the aggressive nature of early-onset breast cancer, and to identify potential drivers of early-onset breast cancer using gene expression profiling datasets in a population-dependent manner. Methods: Functional genomics experiments data were acquired from cBioPortal database for cancer genomics, followed by the stratification of patients based on the age at representation of breast cancer and race. Differential gene expression analysis and gene amplification status analysis were carried out, followed by hub gene, transcription factor, and signalling pathway identification. Results: PAM50 subtype analysis revealed that young patients (≤45 years-old) had four-fold more basal tumors and worst progression-free survival (median of 101 months), compared with the 45-65 years group (median of 168 months). Fourteen genes were amplified in more than 14% of patients with an early-onset breast cancer. Interestingly, FREM2, LINC00332, and LINC00366 were exclusively amplified in younger patients. Gene expression data from three different populations (Asian, White, and African) revealed a unique transcriptomic profile of young patients, which was also reflected on the PAM50 subtype analysis. Our data indicates a higher tendency of young African patients to develop basal tumors, while young Asian patients are more prone to developing Luminal A tumors. Most genes that were found to be upregulated in younger patients are involved in important signaling pathways that promote cancer progression and metastasis, such as MAPK pathway, Reelin pathway and the PI3K/Akt pathway. Conclusion: This study provides strong evidence that the molecular profile of tumors derived from young breast cancer patients of different populations is unique and may explain the aggressiveness of these tumors, stressing the need to conduct population- based multi-omic analyses to identify the potential drivers for tumorigenesis and molecular profiles of young breast cancer patients.

Inhibition of NF-kB/IL-6/JAK2/STAT3 Pathway and Epithelial-Mesenchymal Transition in Breast Cancer Cells by Azilsartan

Metastatic breast cancer is an incurable form of breast cancer that exhibits high levels of epithelial-mesenchymal transition (EMT) markers. Angiotensin II has been linked to various signaling pathways involved in tumor cell growth and metastasis. The aim of this study is to investigate, for the first time, the anti-proliferative activity of azilsartan, an angiotensin II receptor blocker, against breast cancer cell lines MCF-7 and MDA-MB-231 at the molecular level. Cell viability, cell cycle, apoptosis, colony formation, and cell migration assays were performed. RT-PCR and western blotting analysis were used to explain the molecular mechanism. Azilsartan significantly decreased the cancer cells survival, induced apoptosis and cell cycle arrest, and inhibited colony formation and cell migration abilities. Furthermore, azilsartan reduced the mRNA levels of NF-kB, TWIST, SNAIL, SLUG and bcl2, and increased the mRNA level of bax. Additionally, azilsartan inhibited the expression of IL-6, JAK2, STAT3, MMP9 and bcl2 proteins, and increased the expression of bax, c-PARP and cleaved caspase 3 protein. Interestingly, it reduced the in vivo metastatic capacity of MDA-MBA-231 breast cancer cells. In conclusion, the present study revealed, for the first time, the anti-proliferative, apoptotic, anti-migration and EMT inhibition activities of azilsartan against breast cancer cells through modulating NF-kB/IL-6/JAK2/STAT3/MMP9, TWIST/SNAIL/SLUG and apoptosis signaling pathways.

Brain Microvascular Pericytes—More than Bystanders in Breast Cancer Brain Metastasis

Brain tissue contains the highest number of perivascular pericytes compared to other organs. Pericytes are known to regulate brain perfusion and to play an important role within the neurovascular unit (NVU). The high phenotypic and functional plasticity of pericytes make this cell type a prime candidate to aid physiological adaptations but also propose pericytes as important modulators in diverse pathologies in the brain. This review highlights known phenotypes of pericytes in the brain, discusses the diverse markers for brain pericytes, and reviews current in vitro and in vivo experimental models to study pericyte function. Our current knowledge of pericyte phenotypes as it relates to metastatic growth patterns in breast cancer brain metastasis is presented as an example for the crosstalk between pericytes, endothelial cells, and metastatic cells. Future challenges lie in establishing methods for real-time monitoring of pericyte crosstalk to understand causal events in the brain metastatic process.

Ginsenoside CK Inhibits TGF-β-Induced Epithelial-Mesenchymal Transition in A549 Cell via SIRT1

Ginsenoside CK is the main metabolite of protopanaxadiol saponins in intestinal bacteria. Previous studies have shown that ginsenoside CK can affect many aspects of tumor development through a variety of mechanisms. However, few studies have reported the antimetastatic effects of ginsenoside CK in non-small-cell lung cancer (NSCLC). In this study, we explored the effect of ginsenoside CK on epithelial-mesenchymal transition (EMT) induced by TGF-β in A549 cells and the potential molecular mechanisms. Our data showed that ginsenoside CK effectively prevented TGF-β-induced EMT, as indicated by the upregulation of E-cadherin and downregulation of vimentin. Furthermore, ginsenoside CK inhibited the metastatic ability of A549 cells in the tail vein lung metastasis model of nude mice. Additionally, ginsenoside CK decreased the expression of silent information regulator 2 homolog 1 (SIRT1) in the inhibition of EMT induced by TGF-β. Moreover, the antimetastatic effect of ginsenoside CK was reversed by SIRT1 overexpression. Generally, our results indicated the antimetastatic effect and underlying mechanism of ginsenoside CK on TGF-β-induced EMT in A549 cells, suggesting that ginsenoside CK can be used as an effective antineoplastic agent.

Angiotensin II promotes primary tumor growth and metastasis formation of murine TNBC 4T1 cells through the fibroblasts around cancer cells

Angiotensin II (Ang II) reportedly facilitates primary tumor growth and distal hematogenous metastasis formation in various murine intravenous metastasis models. However, it is unclear whether Ang II accelerates the initial processes of metastasis formation that begins in primary tumors surrounded by tumor microenvironment. We examined the effects of Ang II on primary tumors and lung metastasis lesions using a murine spontaneous metastasis model, in which triple negative breast cancer 4T1 cells constitutively expressing luciferase (4T1-Luc cells) were injected into the mammary fat pad of BALB/c mice. Subcutaneous injection of Ang II significantly accelerated primary tumor growth and lung metastasis formation. Ang II increased the protein expression levels of c-Myc, cyclin D1, fibronectin, vimentin, αSMA and Snail, and the treatment with the Ang II type 1 receptor blocker valsartan significantly suppressed the Ang II-induced increases of fibronectin and vimentin. Valsartan also significantly reduced lung metastatic lesions. However, Ang II did not have significant effects on 4T1-Luc cells including the proliferation, migration, invasion, or the expressions of proteins related to cell proliferation and epithelial-to-mesenchymal transition. In contrast, when 4T1-Luc cells were co-cultured with dermal fibroblasts, Ang II significantly accelerated cell migration and increased the expressions of fibronectin, vimentin, αSMA and Snail in 4T1-Luc cells. And moreover, Ang II significantly increased the mRNA expression of IL-6 in fibroblasts co-cultured with 4T1-Luc cells. These results suggested that Ang II accelerates surrounding fibroblasts by soluble factors such as IL-6 to promote epithelial-to-mesenchymal transition, which result in the initiation of cancer metastasis.

Serum anti-AP3D1 antibodies are risk factors for acute ischemic stroke related with atherosclerosis

Atherosclerosis has been considered as the main cause of morbidity, mortality, and disability worldwide. The first screening for antigen markers was conducted using the serological identification of antigens by recombinant cDNA expression cloning, which has identified adaptor-related protein complex 3 subunit delta 1 (AP3D1) as an antigen recognized by serum IgG antibodies of patients with atherosclerosis. Serum antibody levels were examined using the amplified luminescent proximity homogeneous assay-linked immunosorbent assay (AlphaLISA) using a recombinant protein as an antigen. It was determined that the serum antibody levels against AP3D1 were higher in patients with acute ischemic stroke (AIS), transient ischemic attack, diabetes mellitus (DM), cardiovascular disease, chronic kidney disease (CKD), esophageal squamous cell carcinoma (ESCC), and colorectal carcinoma than those in the healthy donors. The area under the curve values of DM, nephrosclerosis type of CKD, and ESCC calculated using receiver operating characteristic curve analysis were higher than those of other diseases. Correlation analysis showed that the anti-AP3D1 antibody levels were highly associated with maximum intima-media thickness, which indicates that this marker reflected the development of atherosclerosis. The results of the Japan Public Health Center-based Prospective Study indicated that this antibody marker is deemed useful as risk factors for AIS.

Combinatorial targeting of microRNA-26b and microRNA-101 exerts a synergistic inhibition on cyclooxygenase-2 in brain metastatic triple-negative breast cancer cells

PURPOSE

Extravasation of triple-negative (TN) metastatic breast cancer (BC) cells through the brain endothelium (BE) is a critical step in brain metastasis (BM). During extravasation, metastatic cells induce alteration in the inter-endothelial junctions and transmigrate through the endothelial barrier. Transmigration of metastatic cells is mediated by the upregulation of cyclooxygenase-2 (COX-2) that induces matrix metalloproteinase-1 (MMP-1) capable of degrading inter-endothelial junctional proteins. Despite their important role in BM, the molecular mechanisms upregulating COX-2 and MMP-1 in TNBC cells remain poorly understood. In this study, we unraveled a synergistic effect of a pair of micro-RNAs (miR-26b-5p and miR-101-3p) on COX-2 expression and the brain transmigration ability of BC cells.

METHODS

Using a gain-and-loss of function approach, we modulated levels of miR-26b-5p and miR-101-3p in two TNBC cell lines (the parental MDA-MB-231 and its brain metastatic variant MDA-MB-231-BrM2), and examined the resultant effect on COX-2/MMP-1 expression and the transmigration of cancer cells through the BE.

RESULTS

We observed that the dual inhibition of miR-26b-5p and miR-101-3p in BC cells results in higher increase of COX-2/MMP-1 expression and a higher trans-endothelial migration compared to either micro-RNA alone. The dual restoration of both micro-RNAs exerted a synergistic inhibition on COX-2/MMP-1 by targeting COX-2 and potentiated the suppression of trans-endothelial migration compared to single micro-RNA.

CONCLUSION

These findings provide new insights on a synergism between miR-26-5p and miR-101-3p in regulating COX-2 in metastatic TNBC cells and shed light on miR-26-5p and miR-101-3p as prognostic and therapeutic targets that can be exploited to predict or prevent BM.

Angiotensin II enhances the proliferation of Natural Killer/T-cell lymphoma cells via activating PI3K/Akt signaling pathway

The present study was to determine the roles of Angiotensin (Ang) II in the growth of lymphoma in nude mice and the proliferation and viability of the human Natural Killer/T (NK/T)-cell lymphoma cell line SNK-6, and the activation of downstream signaling pathway. Lymphoma samples and corresponding normal tissues were obtained from lymphoma patients. Proliferation of SNK-6 cells was detected by CCK8 or MTT assay. The levels of Ang II and its receptor Ang II type 1 receptor (AT1R) were higher in lymphoma tissues than those in control tissues. Ang II increased the lymphoma volume and size in nude mice, the proliferation and viability and the proliferating cell nuclear antigen (PCNA) and Ki67 levels of SNK-6 cells. Losartan, an antagonist of AT1R, reduced lymphoma volume and size in nude mice, and the proliferation and viability and the PCNA and Ki67 levels of SNK-6 cells. The levels of phosphorylated phosphatidylinositol 3-kinase (p-PI3K) and phosphorylated protein kinase B (p-Akt) were increased by Ang II and then reduced by losartan in SNK-6 cells. The proliferation and viability of SNK-6 cells were increased by Ang II, but these increases were inhibited by PI3K inhibitor wortmannin and Akt inhibitor MK2206. The increases of PCNA and Ki67 induced by Ang II were inhibited by wortmannin or MK2206 in SNK-6 cells. These results indicate that Ang II/AT1R is activated in lymphoma, and Ang II promotes the progression of lymphoma in nude mice and the proliferation and viability of SNK-6 cells via activating PI3K/Akt signaling pathway.

Angiotensin II and Angiotensin Receptors 1 and 2-Multifunctional System in Cells Biology, What Do We Know?

For years, the renin-angiotensin system (RAS) has been perceived as a system whose role is to primarily modulate the functioning of the cardiovascular system. Years of research into the role of RAS have provided the necessary data to confirm that the role of RAS is very complex and not limited to the cardiovascular system. The presence of individual elements of the renin-angiotensin (RA) system allows to control many processes, ranging from the memorization to pro-cancer processes. Maintaining the proportions between the individual axes of the RA system allows for achieving a balance, often called homeostasis. Thus, any disturbance in the expression or activity of individual RAS elements leads to pathophysiological processes.

Silencing miR-202-3p increases MMP-1 and promotes a brain invasive phenotype in metastatic breast cancer cells

BACKGROUND

Brain metastasis (BM) is a major cause of morbidity and mortality in breast cancer (BC) and its molecular mechanism remains poorly understood. Transmigration of metastatic cells through the brain endothelium is an essential step in BM. Metalloproteinase-1 (MMP-1) overexpression plays a key role in promoting trans-endothelial migration by degrading the inter-endothelial junctions and disrupting the endothelial integrity. However, little is known about the molecular mechanisms that induce MMP-1 in metastatic cells granting them a brain invasive phenotype. MiR-202-3p is downregulated in brain metastases compared to primary breast tumors and directly targets MMP-1. Here, we unraveled a critical role of miR-202-3p loss in MMP-1 upregulation promoting transmigration of metastatic cells through the brain endothelium.

METHODS

A variant of the MDA-MB-231 human BC cell line (MDA-MB-231-BrM2) selected for its propensity to form brain metastases was found to express high levels of MMP-1 and low levels of miR-202-3p compared to the parental cells. Using a gain-and-loss of function approach, we modulated levels of miR-202-3p and examined the resultant effect on MMP-1 expression. Effect of miR-202-3p modulation on integrity of the brain endothelium and the transmigrative ability of BC cells were also examined.

RESULTS

Loss of miR-202-3p in breast cancer cells enhanced their transmigration through the brain endothelium by upregulating MMP-1 and disrupting the inter-endothelial junctions (claudin-5, ZO-1 and ß-catenin). Restoring miR-202-3p exerted a metastasis-suppressive effect and preserved the endothelial barrier integrity.

CONCLUSIONS

Our study identified a critical regulatory role of miR-202-3p in brain metastasis and shed light on miR-202-3p/MMP-1 axis as a novel prognostic and therapeutic target that can be exploited to predict and prevent brain metastasis in breast cancer patients.

Targeting lung cancer stem cells using combination of Tel and Docetaxel liposomes in 3D cultures and tumor xenografts

Cancer stem cells (CSCs) accounts for recurrence and resistance to chemotherapy in various tumors. Efficacy of chemotherapeutic drugs is limited by tumor stromal barriers, which hinder their penetration into deep tumor sites. We have earlier shown telmisartan (Tel) pretreatment prior to Docetaxel (DTX) administration enhances anti-cancer effects in non-small cell lung cancer (NSCLC). Herein, we demonstrated for the first time the efficacy of Docetaxel liposomes (DTXPL) in combination with Tel in 3D cultures of H460 cells by using polysaccharide-based hydrogels (TheWell Biosciences) and also in xenograft model of DTX resistant H460 derived CD133+ lung tumors. DTXPL and Tel combination showed enhanced cytotoxicity in H460 WT 3D cultures by two folds. In H460 3D cultures, Tel pretreatment showed increased liposomal uptake. DTXPL and Tel combination treated tumors showed reduction in tumor volume (p < .001), increased apoptosis and downregulation of CSC markers (p < .01) in H460 WT and DTX resistant CD133+ xenograft models.

ATIP3 deficiency facilitates intracellular accumulation of paclitaxel to reduce cancer cell migration and lymph node metastasis in breast cancer patients

Taxane-based chemotherapy is frequently used in neoadjuvant treatment of breast cancer patients to reduce tumor growth and lymph node metastasis. However, few patients benefit from chemotherapy and predictive biomarkers of chemoresistance are needed. The microtubule-associated protein ATIP3 has recently been identified as a predictive biomarker whose low levels in breast tumors are associated with increased sensitivity to chemotherapy. In this study, we investigated whether ATIP3 deficiency may impact the effects of paclitaxel on cancer cell migration and lymph node metastasis. Expression levels of ATIP3 were analyzed in a cohort of 133 breast cancer patients and classified according to lymph node positivity following neoadjuvant chemotherapy. Results showed that low ATIP3 levels are associated with reduced axillary lymph node metastasis. At the functional level, ATIP3 depletion increases cell migration, front-rear polarity and microtubule dynamics at the plus ends, but paradoxically sensitizes cancer cells to the inhibitory effects of paclitaxel on these processes. ATIP3 silencing concomitantly increases the incorporation of fluorescent derivative of Taxol along the microtubule lattice. Together our results support a model in which alterations of microtubule plus ends dynamics in ATIP3-deficient cells may favor intracellular accumulation of paclitaxel, thereby accounting for increased breast tumor sensitivity to chemotherapy.

AGTR1 promotes lymph node metastasis in breast cancer by upregulating CXCR4/SDF-1α and inducing cell migration and invasion

The angiotensin II type I receptor (AGTR1) has a strong influence on tumor growth, angiogenesis, inflammation and immunity. However, the role of AGTR1 on lymph node metastasis (LNM) in breast cancer, which correlates with tumor progression and patient survival, has not been examined. AGTR1 was highly expressed in lymph node-positive tumor tissues, which was confirmed by the Oncomine database. Next, inhibition of AGTR1 reduced tumor growth and LNM in orthotopic xenografts by bioluminescence imaging (BLI). Losartan, an AGTR1-specific inhibitor, decreased the chemokine pair CXCR4/SDF-1α levels in vivo and inhibited AGTR1-induced cell migration and invasion in vitro. Finally, the molecular mechanism of AGTR1-induced cell migration and LNM was assessed by knocking down AGTR1 in normal cells or CXCR4 in AGTR1^high cells. AGTR1-silenced cells treated with losartan showed lower CXCR4 expression. AGTR1 overexpression caused the upregulation of FAK/RhoA signaling molecules, while knocking down CXCR4 in AGTR1^high cells downregulated these molecules. Collectively, AGTR1 promotes LNM by increasing the chemokine pair CXCR4/SDF-1α and tumor cell migration and invasion. The potential mechanism of AGTR1-mediated cell movement relies on activating the FAK/RhoA pathway. Our study indicated that inhibiting AGTR1 may be a potential therapeutic target for LNM in early-stage breast cancer.

Renin-Angiotensin System in Lung Tumor and Microenvironment Interactions

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.

Therapeutic potential of renin angiotensin system inhibitors in cancer cells metastasis

Metastasis is a complex process which contributes to the dissemination of cancer cells to other organs and forms new tumor sites. The proliferation of tumor cells is a necessary step for the initiation and progression of cancers and is associated with the formation of new vessels. In the latter stages of metastasis, cancer cells may spread into the extracellular matrix and may form metastatic nodules. Despite efforts to prevent this, effective therapies are limited in the treatment of some malignancies. Among the different tumor properties which could be usefully employed as a cancer target, metastasis may be one suitable target. The renin- angiotensin system is a physiological pathway that contributes to the proliferation of tumor cells, angiogenesis and the inflammatory response in tumor tissue. Angiotensin II (ANGII), a key peptide of this pathway, induces cell proliferation through the activation of two cellular pathways (mitogen-activated protein kinase (MAPK)-STAT3 and phosphoinositide 3-kinase (PI3K) -AKT pathway). AT1-R increases angiogenesis via the elevation of angiogenic factors expression (vascular endothelial growth factor (VEGF) and matrix metallopeptidases (MMPs)). The local activation of the RAS pathway increases the expression of ICAM, VCAM and MMPs genes that are involved in the late steps of the metastasis process. There is some evidence that RAS components are expressed in metastatic tumors and RASIs (renin-angiotensin system inhibitors) could be used to reduce cancer metastasis by affecting the mechanisms involved in several different cancers. Therefore, we have summarized the effects of RASIs, observed in pre-clinical and clinical studies of cancer cell metastasis.

Angiotensin receptor autoantibodies as exposures that modify disease progression: Cross sectional, longitudinal and in vitro studies of prostate cancer

Circulating angiotensin type I receptor (AT1R) agonistic autoantibodies (AT1RaAbs) that bind and chronically activate the receptor have been associated with a number of diseases suggesting that while the autoantibodies are not necessarily causative they may promote disease progression. The prostate has a local renin angiotensin system. The current study examines associations between AT1RaAbs and prostate cancer (PCA), disease-free survival (DFS), overall survival (OS) and AT1RaAb effects on PCA cell phenotype. In a cross-sectional set of serum obtained from 151 men diagnosed with PCA, nonmalignant prostate disease or no disease, higher serum AT1RaAb levels were associated with PCA and non-organ confined PCA. The odds ratio for PCA was 6.3 (95% confidence interval 2.2 to 18) for a positive 1:1600 titer and 18 (95% confidence interval 6.9 to 45) at AT1RaAb levels > 1.04 μg/ml, (p < 0.0001). In a longitudinal set of pre-diagnosis samples from 109 men, DFS hazard ratios of 2.2 (95% confidence interval 1.4 to 3.5) and 1.6 (95% confidence interval 1.0 to 2.5) for most proximal to diagnosis and most distal to diagnosis samples, respectively, were found for high versus low AT1RaAb groups. Hazard ratios for OS in most proximal and distal samples were 2.4 (95% confidence interval 1.6 to 3.6) and 1.8 (95% confidence interval 1.1 to 2.8), respectively. Accelerated failure modeling of survival indicated that a 1 μg/ml increase in AT1RaAb levels was associated with a reduction of DFS and OS by 20% at the most proximal time point and by 15% at the most distal time points. Adjusting for age, did not affect the association with DFS in proximal samples but changed distal time point DFS and OS to a 10% decrease for every 1 μg/ml increase in AT1RaAb. Additional adjustments for body mass index, systolic blood pressure and prostate-specific antigen did not appreciably alter these associations. AT1RaAb treatment of PC3, DU145, and LNCaP cells significantly increased the maximal growth rate approximately 2-fold and invasiveness approximately 3-fold. Conclusions: These observations provide evidence supporting AT1RaAbs as exposures that may modify prostate cancer progression and indicate they may be predictive markers for risk stratification.

Fibroblastic Reticular Cells Control Conduit Matrix Deposition during Lymph Node Expansion

Lymph nodes (LNs) act as filters, constantly sampling peripheral cues. This is facilitated by the conduit network, a tubular structure of aligned extracellular matrix (ECM) fibrils ensheathed by fibroblastic reticular cells (FRCs). LNs undergo rapid 3- to 5-fold expansion during adaptive immune responses, but these ECM-rich structures are not permanently damaged. Whether conduit flow or filtering function is affected during LN expansion is unknown. Here, we show that conduits are partially disrupted during acute LN expansion, but FRC-FRC contacts remain connected. We reveal that polarized FRCs deposit ECM basolaterally using LL5-β and that ECM production is regulated at transcriptional and secretory levels by the C-type lectin CLEC-2, expressed by dendritic cells. Inflamed LNs maintain conduit size exclusion, and flow is disrupted but persists, indicating the robustness of this structure despite rapid tissue expansion. We show how dynamic communication between peripheral tissues and LNs provides a mechanism to prevent inflammation-induced fibrosis in lymphoid tissue.

A Novel Zebrafish Model of Metastasis Identifies the HSD11β1 Inhibitor Adrenosterone as a Suppressor of Epithelial-Mesenchymal Transition and Metastatic Dissemination

Metastasis of cancer cells is multi-step process and dissemination is an initial step. Here we report a tamoxifen-controllable Twist1a-ER^T2 transgenic zebrafish line as a new animal model for metastasis research, and demonstrate that this model can serve as a novel platform for discovery of antimetastasis drugs targeting metastatic dissemination of cancer cells. By crossing Twist1a-ER^T2 with xmrk (a homolog of hyperactive form of EGFR) transgenic zebrafish, which develops hepatocellular carcinoma, approximately 80% of the double transgenic zebrafish showed spontaneous cell dissemination of mCherry-labeled hepatocytes from the liver to the entire abdomen region and the tail region. The dissemination is accomplished in 5 days through induction of an epithelial-to-mesenchymal transition. Using this model, we conducted in vivo drug screening and identified three hit drugs. One of them, adrenosterone, an inhibitor for hydroxysteroid (11-beta) dehydrogenase 1 (HSD11β1), has a suppressor effect on cell dissemination in this model. Pharmacologic and genetic inhibition of HSD11β1 suppressed metastatic dissemination of highly metastatic human cell lines in a zebrafish xenotransplantation model. Through downregulation of Snail and Slug, adrenosterone-treated cells recovered expression of E-cadherin and other epithelial markers and lost partial expression of mesenchymal markers compared with vehicle-treated cells. Taken together, our model offers a useful platform for the discovery of antimetastasis drugs targeting metastatic dissemination of cancer cells. IMPLICATIONS: This study describes a transgenic zebrafish model for liver tumor metastasis and it has been successfully used for identification of some drugs to inhibit metastatic dissemination of human cancer cells.

Breast cancer brain metastasis: molecular mechanisms and directions for treatment

The development of brain metastasis (BM) of breast cancer is usually a late event with deleterious effect on the prognosis. Treatment options for intracerebral seeding of breast cancer are limited and, so far, nonspecific. Molecular detailing of subsequent events of penetration, seeding, and outgrowth in brain is highly relevant for developing therapeutic strategies to treat, or prevent, BM.We scrutinize recent literature for molecules and pathways that are operative in the formation of breast cancer BM. We also summarize current data on therapeutic efforts to specifically address BM of breast cancer. Data on molecular pathways underlying the formation of BM of breast cancer are sketchy and to some extent inconsistent. The molecular makeup of BM differs from that of the primary tumors, as well as from metastases at other sites. Current efforts to treat breast cancer BM are limited, and drugs used have proven effects on the primary tumors but lack specificity for the intracerebral tumors.More basic research is necessary to better characterize BM of breast cancer. Apart from the identification of drug targets defined by the intracerebral tumors, also targets in the molecular pathways involved in passing the blood-brain barrier and intracerebral tumor cell growth should be revealed.

Extracellular Hsp90α and clusterin synergistically promote breast cancer epithelial-to-mesenchymal transition and metastasis via LRP1

Extracellular heat shock protein 90 alpha (eHsp90α, also known as HSP90AA1) has been widely reported to promote tumor cell motility and tumor metastasis in various types of cancer. Several extracellular proteins and membrane receptors have been identified as interacting proteins of eHsp90α and mediate its pro-metastasis function. However, the regulatory mechanism of eHsp90α activity remains largely unknown. Here, we report that clusterin, a protein newly demonstrated to interact with eHsp90α, modulates eHsp90α signaling. We found that clusterin potentiated the effects of eHsp90α on activation of the AKT, ERK and NF-κB protein families, epithelial-to-mesenchymal transition (EMT) and migration in breast cancer cells. Furthermore, in vivo investigations demonstrated similar synergistic effects of eHsp90α and clusterin on tumor metastasis. Notably, the effects of eHsp90α and clusterin were mediated by low-density lipoprotein receptor-related protein 1 (LRP1). Proximity ligation assay and co-immunoprecipitation experiments demonstrated that clusterin participated in eHsp90α-LRP1 complex formation, which enhanced the binding affinity of eHsp90α to LRP1. Collectively, our data establish a role of clusterin as a newly discovered modulator of eHsp90α, and unravel detailed molecular mechanisms underlying the synergistic metastasis-promoting effects of clusterin and eHsp90α.

EXPRESSION OF THE RENIN-ANGIOTENSIN SYSTEM COMPONENTS IN ONCOLOGIC DISEASES

The literature devoted to changes in the expression of the renin-angiotensin system (RAS) proteins of cancer cells was analyzed. The dynamics of RAS protein expression in malignant tumors and the possible role of epigenetic mechanisms in these processes are briefly reviewed. Through research of the epigenetic mechanisms in cancer, principally new techniques for their correction based on the use of selective regulatory systems of covalent modification of histone proteins (for example, deacetylase inhibitor) and microRNA synthesis technologies have been developed. Literature data show promising pharmacological correction of epigenetic modification of chromatin in the treatment of cancer.

20(S)-Protopanaxadiol Inhibits Angiotensin II-Induced Epithelial- Mesenchymal Transition by Downregulating SIRT1

20(S)-Protopanaxadiol (PPD) is one of the major active metabolites in ginseng saponin. Our previous studies revealed a broad spectrum of antitumor effects of PPD. Angiotensin II (Ang II), the biologically active peptide of the renin-angiotensin system (RAS), plays a critical role in the metastasis of various cancers. However, its role in the anti-metastatic effects of PPD is not clearly understood. In this study, we investigated the inhibitory effect of PPD on Ang II-induced epithelial-mesenchymal transition (EMT) in non-small cell lung cancer (NSCLC) cells, and the potential molecular mechanisms of suppression of NSCLC migration and metastasis by PPD. Treatment of A549 cells with Ang II increased metastases in an experimental model of cancer metastasis in vivo. PPD effectively prevented Ang II-induced EMT, as indicated by upregulation of E-cadherin and downregulation of vimentin. Additionally, Ang II upregulated the class III deacetylase sirtuin 1 (SIRT1) expression in EMT progression, while downregulation of SIRT1 was involved in suppression of Ang II-induced EMT by PPD. Moreover, the inhibitory effect of PPD was reversed by SIRT1 upregulation, and PPD demonstrated synergy with an SIRT1 inhibitor on Ang II-induced EMT. Taken together, our data reveal the mechanism of the anti-metastatic effects of PPD on Ang II-induced EMT and indicate that PPD can be used as an effective anti-tumor treatment.

Phenotypic and Expressional Heterogeneity in the Invasive Glioma Cells

BACKGROUND: Tumor cell invasion is a hallmark of glioblastoma (GBM) and a major contributing factor for treatment failure, tumor recurrence, and the poor prognosis of GBM. Despite this, our understanding of the molecular machinery that drives invasion is limited. METHODS: Time-lapse imaging of patient-derived GBM cell invasion in a 3D collagen gel matrix, analysis of both the cellular invasive phenotype and single cell invasion pattern with microarray expression profiling. RESULTS: GBM invasion was maintained in a simplified 3D-milieue. Invasion was promoted by the presence of the tumorsphere graft. In the absence of this, the directed migration of cells subsided. The strength of the pro-invasive repulsive signaling was specific for a given patient-derived culture. In the highly invasive GBM cultures, the majority of cells had a neural progenitor-like phenotype, while the less invasive cultures had a higher diversity in cellular phenotypes. Microarray expression analysis of the non-invasive cells from the tumor core displayed a higher GFAP expression and a signature of genes containing VEGFA, hypoxia and chemo-repulsive signals. Cells of the invasive front expressed higher levels of CTGF, TNFRSF12A and genes involved in cell survival, migration and cell cycle pathways. A mesenchymal gene signature was associated with increased invasion. CONCLUSION: The GBM tumorsphere core promoted invasion, and the invasive front was dominated by a phenotypically defined cell population expressing genes regulating traits found in aggressive cancers. The detected cellular heterogeneity and transcriptional differences between the highly invasive and core cells identifies potential targets for manipulation of GBM invasion.

The role of angiotensin II in cancer metastasis: Potential of renin-angiotensin system blockade as a treatment for cancer metastasis

Hypertension, which often exists as a comorbid condition in cancer patients, is considered as a factor affecting cancer progression. The renin-angiotensin system (RAS) plays an important role in the regulation of blood pressure, and angiotensin II (Ang II) is a well-known pressor peptide in RAS. There is also accumulated evidence indicating that Ang II plays a critical role in the metastasis of various cancers by modulating adhesion, migration invasion, proliferation, and angiogenesis. Consistent with this, large epidemiological studies have reported the potential beneficial effects of angiotensin-converting enzyme (ACE) inhibitors and Ang II type 1 receptor blockers (ARBs) against cancer metastasis; however, some of the results remain controversial. Although the precise Ang II-related mechanisms involved in cancer metastasis are not completely clear yet, a number of basic and meta-analytic studies have shown that ACE inhibitors and ARBs reduce the metastatic potential of tumors. In this review, we summarize the relationships among hypertension, RAS, and metastasis as demonstrated in basic and clinical studies. Finally, we discuss the possibility of using RAS inhibitors as anti-metastatic drugs.

Telmisartan inhibits NSCLC A549 cell proliferation and migration by regulating the PI3K/AKT signaling pathway

Expression of angiotensin II (Ang II), a key biological peptide in the renin-angiotensin system, is closely associated with the occurrence and development of cancer. Ang II binds two receptor subtypes, the Ang II type 1 receptor (AT1R) and the AT2R, to mediate a series of biological effects. Telmisartan, a specific AT1R blocker, has been reported to have potential as an anticancer drug for treating renal cancer. In the present study, whether telmisartan had an effect on non-small cell lung cancer (NSCLC) cell proliferation and migration was investigated. The Cell Counting kit-8 assay revealed that telmisartan significantly inhibited the growth of the NSCLC A549 cell line in a time- and dose-dependent manner. In a transwell assay, telmisartan significantly inhibited cellular invasion and migration. Furthermore, it was determined that the expression of the anti-apoptotic protein B-cell lymphoma was decreased, and that of the pro-apoptotic proteins caspase-3 and Bcl-associated X increased in the A549 cells treated with telmisartan. Additionally, levels of phosphorylated RAC serine/threonine-protein kinase (p-AKT), p-mechanistic target of rapamycin, p70-S6 kinase and cyclin D1 was decreased in the telmisartan-treated group. Therefore, the current study reveals that telmisartan-induced NSCLC apoptosis may be regulated via the phosphoinositide 3-kinase/AKT signaling pathway, which indicates that it may be a potential novel drug for clinical NSCLC treatment.

Angiotensin-(1-7) counteracts the transforming effects triggered by angiotensin II in breast cancer cells

Angiotensin (Ang) II, the main effector peptide of the renin-angiotensin system, has been implicated in multiple aspects of cancer progression such as proliferation, migration, invasion, angiogenesis and metastasis. Ang-(1-7), is a biologically active heptapeptide, generated predominantly from AngII by the enzymatic activity of angiotensin converting enzyme 2. Previous studies have shown that Ang-(1-7) counterbalances AngII actions in different pathophysiological settings. In this study, we have analysed the impact of Ang-(1-7) on AngII-induced pro-tumorigenic features on normal murine mammary epithelial cells NMuMG and breast cancer cells MDA-MB-231. AngII stimulated the activation of the survival factor AKT in NMuMG cells mainly through the AT1 receptor. This PI3K/AKT pathway activation also promoted epithelial–mesenchymal transition (EMT). Concomitant treatment of NMuMG cells with AngII and Ang-(1-7) completely abolished EMT features induced by AngII. Furthermore, Ang-(1-7) abrogated AngII induced migration and invasion of the MDA-MB-231 cells as well as pro-angiogenic events such as the stimulation of MMP-9 activity and VEGF expression. Together, these results demonstrate for the first time that Ang-(1-7) counteracts tumor aggressive signals stimulated by AngII in breast cancer cells emerging the peptide as a potential therapy to prevent breast cancer progression.

Antihypertensive drug use and breast cancer risk: a meta-analysis of observational studies

We conducted a meta-analysis of observational studies to examine the hypothesized association between breast cancer and antihypertensive drug (AHT) use. Fixed- or random- effect models were used to calculate pooled risk ratios (RRs) and 95% confidence intervals (CIs) for all AHTs and individual classes (i.e., angiotensin-converting enzyme inhibitors, [ACEi]; angiotensin-receptor blockers, [ARBs]; calcium channel blockers, [CCBs]; beta-blockers, [BBs], and diuretics). Twenty-one studies with 3,116,266 participants were included. Overall, AHT use was not significantly associated with breast cancer risk (RR = 1.02, 95% CI: 0.98-1.06), and no consistent association was found for specific AHT classes with pooled RRs of 1.02 (95% CI: 0.96-1.09) for BBs, 1.07 (95% CI: 0.99-1.16) for CCBs, 0.99 (95% CI: 0.93-1.05) for ACEi/ARBs, and 1.05 (95% CI: 0.99-1.12) for diuretics. When stratified by duration of use, there was a significantly reduced breast cancer risk for ACEi/ARB use ≥10 years (RR = 0.80, 95% CI: 0.67-0.95). Although there was no significant association between AHT use and breast cancer risk, there was a possible beneficial effect was found for long-term ACEi/ARB. Large, randomized controlled trials with long-term follow-up are needed to further test the effect of these medications on breast cancer risk.

The ACE2/Angiotensin-(1-7)/Mas Receptor Axis: Pleiotropic Roles in Cancer

Cancer remains one of the most common causes of death and disability and represents a major economic burden in industrialized nations. The renin-angiotensin system (RAS) has been well-recognized as one of the most important regulators of both normal and pathological physiological processes in the brain, kidney, heart, and blood vessels. The activation of the angiotensin-converting enzyme 2/angiotensin-(1–7)/mitochondrial assembly receptor [ACE2/Ang-(1–7)/MasR] axis, which is one component of the RAS, has recently been identified as a critical component of pulmonary systems, gastric mucosa, and cancer. However, the ability of the ACE2/Ang-(1–7)/MasR axis to suppress or promote cancer has not been fully elucidated. In this review, we focus on recent experimental and clinical studies investigating the basic properties, roles, and mechanisms of ACE2, Ang-(1–7), and the MasR, as well as the axis pathway, to provide insights into possible therapeutic strategies for treating cancer that target the ACE2/Ang-(1–7)/MasR axis.

Angiotensin II receptor blockers induce autophagy in prostate cancer cells

Angiotensin II receptor blockers (ARBs) are anti-hypertensive drugs that competitively inhibit the binding of angiotensin II to its receptor, resulting in blood vessel dilation and the reduction of blood pressure. These antagonists are also known as sartans, and are a group of pharmaceuticals that possess tetrazole or imidazole groups. In the present study, the anticancer and antimetastatic effects of the ARBs fimasartan, losartan, eprosartan and valsartan on the human prostate cancer PC-3, DU-145 and LNCap-LN3 cell lines were investigated in vitro. The proliferation of the prostate cancer cells was inhibited following treatment with 100 µM ARB. In particular, treatment with fimasartan resulted in marked anti-proliferative activity compared with the other ARBs. With respect to the molecular mechanism of the growth inhibition exhibited by the ARBs, 3-methyladenin (3-MA), an autophagy inhibitor, was revealed to increase the survival rate of PC-3 cells when cell death inhibitors were pretreated with fimasartan. In addition, the ARBs induced autophagy with increased expression levels of autophagy protein (Atg) 5-12, Atg 16-like-1, beclin-1 and microtubule-associated protein 1A/1B-light chain 3 (LC3). Notably, the enhanced expression of LC3-II (a 6.7-fold increase at 72 h) was observed in PC3 cells treated with fimasartan. This was supported by the observation of the time-dependent accumulation of LC3-positive foci in PC-3. In addition, a migration assay indicated that the ARBs induced anti-metastatic effects in PC-3 and DU-145 cells. The aforementioned results suggest that ARBs may induce autophagy-associated cell death and anti-metastatic activity in prostate cancer cells. Thus, ARBs may be a potential medication for patients with prostate cancer and hypertension.

Angiotensin Converting Enzyme Regulates Cell Proliferation and Migration

Background

The angiotensin-I converting enzyme (ACE) plays a central role in the renin-angiotensin system, acting by converting the hormone angiotensin-I to the active peptide angiotensin-II (Ang-II). More recently, ACE was shown to act as a receptor for Ang-II, and its expression level was demonstrated to be higher in melanoma cells compared to their normal counterparts. However, the function that ACE plays as an Ang-II receptor in melanoma cells has not been defined yet.

Aim

Therefore, our aim was to examine the role of ACE in tumor cell proliferation and migration.

Results

We found that upon binding to ACE, Ang-II internalizes with a faster onset compared to the binding of Ang-II to its classical AT1 receptor. We also found that the complex Ang-II/ACE translocates to the nucleus, through a clathrin-mediated process, triggering a transient nuclear Ca²⁺ signal. In silico studies revealed a possible interaction site between ACE and phospholipase C (PLC), and experimental results in CHO cells, demonstrated that the β3 isoform of PLC is the one involved in the Ca²⁺ signals induced by Ang-II/ACE interaction. Further studies in melanoma cells (TM-5) showed that Ang-II induced cell proliferation through ACE activation, an event that could be inhibited either by ACE inhibitor (Lisinopril) or by the silencing of ACE. In addition, we found that stimulation of ACE by Ang-II caused the melanoma cells to migrate, at least in part due to decreased vinculin expression, a focal adhesion structural protein.

Conclusion

ACE activation regulates melanoma cell proliferation and migration.

Angiotensin II promotes endometrial cancer cell survival

Endometrial cancer (EC) is one of the most common female cancers. One of the key processes involved in EC development is uncontrolled proliferation stimulated by local factors such as angiotensin. The aim of the present study was to evaluate the influence of angiotensin II (Ang II) on human EC cells. Biological assays and gene expression analysis were performed on three cell lines: ISH, MFE-296 and MFE-280. Our results indicated that at the beginning of cancerogenesis Ang II induced abnormal proliferation at lower doses. We also showed that dose-dependent induction of proliferation was connected with changes in the expression of MKI67, CCND1 and CCNE1 genes in well- and poorly differentiated cancer cells. After Ang II treatment, poorly differentiated endometrial cancer cell line acquired a mesenchymal phenotype, which was characterized by induced expression of EMT-related genes (VIM, CD44, SNAI1, ZEB1 and ZEB2). Our study revealed that Ang II influences EC cells in terms of cancer-related processes, and is responsible for increased proliferation, reduction in apoptosis, increased mobility and modulation of adhesion potential. Its effect and effectiveness appear to be highly connected with the differentiation status of the cancerous cells, as Ang II appears to play a crucial role in the early and late stages of malignant transformation.

Interaction between angiotensin II and relaxin 2 in the progress of growth and spread of prostate cancer cells

Deregulation of locally secreted hormones, such as angiotensin II (Ang II) and relaxin 2 (RLN2), has been linked to a higher risk of select cancers or a poor prognosis in patients. In this study, for the first time a common effect of Ang II and RLN2 in relation to various aspects of prostate cancer development and metastasis are presented. Four independent colorimetric assays were used to analyze cell viability and proliferation. The changes of cell adhesion to extracellular matrix proteins and invasion/aggressiveness ability of prostate cancer cells (LNCaP, PC3) before and after peptides treatment, were also investigated. The findings suggest that the both investigated systems, have an impact on cell growth/division or spread, to some degree via overlapping signal transduction pathways. Intermediate or sometimes poorer results were achieved by using a combination of both hormones than when each was used individually. It seems that Ang II and RLN2 can play a significant role in increasing the aggressiveness of prostate tumors by up-regulating BIRC5 expression and MMP-2 and MMP-9 secretion. In addition, we speculate that Ang II and RLN2 are involved in the transition from the androgen-dependent to the androgen-independent phenotype via modulation of the expression of androgen receptors.

Overexpression of angiotensin II type 1 receptor in breast cancer cells induces epithelial-mesenchymal transition and promotes tumor growth and angiogenesis

The angiotensin II type I receptor (AGTR1) has been implicated in diverse aspects of human disease, from the regulation of blood pressure and cardiovascular homeostasis to cancer progression. We sought to investigate the role of AGTR1 in cell proliferation, epithelial-mesenchymal transition (EMT), migration, invasion, angiogenesis and tumor growth in the breast cancer cell line MCF7. Stable overexpression of AGTR1 was associated with accelerated cell proliferation, concomitant with increased expression of survival factors including poly(ADP-ribose) polymerase (PARP) and X-linked inhibitor of apoptosis (XIAP), as well as extracellular signal-regulated kinase (ERK) activation. AGTR1-overexpressing MCF7 cells were more aggressive than their parent line, with significantly increased activity in migration and invasion assays. These observations were associated with changes in EMT markers, including reduced E-cadherin expression and increased p-Smad3, Smad4 and Snail levels. Treatment with the AGTR1 antagonist losartan attenuated these effects. AGTR1 overexpression also accelerated tumor growth and increased Ki-67 expression in a xenograft model. This was associated with increased tumor angiogenesis, as evidenced by a significant increase in microvessels in the intratumoral and peritumoral areas, and enhanced tumor invasion, with the latter response associated with increased EMT marker expression and matrix metallopeptidase 9 (MMP-9) upregulation. In vivo administration of losartan significantly reduced both tumor growth and angiogenesis. Our findings suggest that AGTR1 plays a significant role in tumor aggressiveness, and its inhibition may have therapeutic implications.

Pathogenesis of Breast Cancer Metastasis to Brain: a Comprehensive Approach to the Signaling Network

There is a general consensus that breast cancer is a rising trend disease in the world. It is one of the most common cancer types and is the leading cause of death among women's cancers. There are several reasons for this high rate of mortality including metastasis which is responsible for about 90 % of cancer-related mortality. Therefore, recognition and understanding of metastatic process is important, and by considering the key role of pathophysiological route in metastasis as a multistep cascade of "invasion-metastasis," it might modify and improve our insight toward this complex phenomenon. Moreover, it can provide novel approaches for designing advanced targeted therapies. The present work aimed to review the published papers regarding molecular basis of metastatic process of breast cancer to brain metastasis, especially related genes and signaling network. Furthermore, the use of molecular aspects of metastatic breast cancer to brain was discussed in horizon of future treatment of breast cancer.

Protease-activated receptors (PARs) in cancer: Novel biased signaling and targets for therapy

Despite the fact that G protein-coupled receptors (GPCRs) mediate numerous physiological processes and represent targets for therapeutics for a vast array of diseases, their role in tumor biology is under appreciated. Protease-activated receptors (PARs) form a family which belongs to GPCR class A. PAR1&2 emerge with a central role in epithelial malignancies. Although the part of PAR1&2 in cancer is on the rise, their underlying signaling events are poorly understood. We review hereby past, present, and future cancer-associated PAR biology. Mainly, their role in physiological (placenta-cytotophobalst) and patho-physiological invasion processes. The identification and characterization of signal pleckstrin homology (PH)-domain-binding motifs established critical sites for breast cancer growth in PAR1&2. Among the proteins found to harbor important PH-domains and are involved in PAR biology are Akt/PKB as also Etk/Bmx and Vav3. A point mutation in PAR2, H349A, but not R352A, abrogated PH-protein association and is sufficient to markedly reduce PAR2-instigated breast tumor growth in vivo as also placental extravillous trophoblast (EVT) invasion in vitro is markedly reduced. Similarly, the PAR1 mutant hPar1-7A, which is unable to bind PH-domain, inhibits mammary tumors and EVT invasion, endowing these motifs with physiological significance and underscoring the importance of these previously unknown PAR1 and PAR2 PH-domain-binding motifs in both pathological and physiological invasion processes.

The use of angiotensin II receptor antagonists to increase the efficacy of radiotherapy in cancer treatment

Angiotensin II receptor antagonists inhibit various signaling pathways involved in the regulation of inflammation, apoptosis and angiogenesis. Radiation-induced activation of a proinflammatory cytokine network has been shown to mediate normal tissue injury induced by ionizing radiation in cancer patients, resulting in serious side effects. Hence, not only do angiotensin II receptor antagonists block inflammatory signaling both in cancer cells and in normal cells, but they are also effective in the treatment of cancer by inhibiting tumor progression, vascularization and metastasis. This review addresses the role of angiotensin II inhibitors in cancer therapy, and their potential to increase therapeutical index by protecting normal cells and sensitizing tumor cells to radiotherapy.

Matrix-assisted laser desorption/ionisation (MALDI) TOF analysis identifies serum angiotensin II concentrations as a strong predictor of all-cause and breast cancer (BCa)-specific mortality following breast surgery

MALDI-TOF MS was used to recognise serum peptidome profiles predictive of mortality in women affected by early BCa. Mortality was analysed based on signal profiling, and appropriate statistics were used. The results indicate that four signals were increased in deceased patients compared with living patients. Three of the four signals were individually associated with all-cause mortality, but only one having mass/charge ratio (m/z) 1,046.49 was associated with BCa-specific mortality and was the only peak to maintain an independent prognostic role after multivariate analysis. Two groups exhibiting different mortality probabilities were identified after clustering patients based on the expression of the four peptides, but m/z 1,046.49 was exclusively expressed in the cluster exhibiting the worst mortality outcome, thus confirming the crucial value of this peptide. The specific role of this peak was confirmed by competing risk analysis. MS findings were validated by ELISA analysis after demonstrating that m/z 1,046.49 structurally corresponded to Angiotensin II (ATII). In fact, mortality results obtained after arbitrarily dividing patients according to an ATII serum value of 255 pg/ml (which corresponds to the 66(th) percentile value) were approximately comparable to those previously demonstrated when the same patients were analysed according to the expression of signal m/z 1,046.49. Similarly, ATII levels were specifically correlated with BCa-related deaths after competing risk analysis. In conclusion, ATII levels were increased in women who exhibited worse mortality outcomes, reinforcing the evidence that this peptide potentially significantly affects the natural history of early BCa. Our findings also confirm that MALDI-TOF MS is an efficient screening tool to identify novel tumour markers and that MS findings can be rapidly validated through less complex techniques, such as ELISA.

Renin-Angiotensin system blockers may prolong survival of metastatic non-small cell lung cancer patients receiving erlotinib

The aim of this study is to determine whether renin-angiotensin system blockers (RASBs), which include angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin-2 receptor 1 blockers (ARBs), improve the overall survival (OS) of patients with metastatic non-small cell lung cancer (NSCLC).The medical charts of 117 patients with metastatic NSCLC were retrospectively assessed. Thirty-seven patients (RASB group) using RASBs during systemic treatment were compared with 80 controls (control group) who did not use RASBs following the diagnosis of NSCLC. The histological tumor subtype, performance status, age, sex, smoking status, comorbidities, other medications, chemotherapeutics (CT), and erlotinib that were received in any line of treatment were recorded. We compared the OS of the patients in the RASB and control groups.The median (±SD) age of the patients was 61 (±1) years and all patients were administered systemic treatment (CT or erlotinib). The patients in RASB group were more likely to be smokers, have hypertension and ischemic heart disease, and use erlotinib, thiazides, beta-blockers, and calcium-channel blockers (P < 0.05 for all) compared with the control group. The median follow-up time was 18.9 months (range 1-102 months) for the entire group. The median follow-up period was longer for RASB group than control group (17 vs 11 months, P = 0.033). The most commonly prescribed RASB agent was valsartan (n = 12/37). At the time of the analysis, 98 (83.7%) of all patients had died. In the univariate analysis, the median OS was longer in the RASB group compared with the control group (17 [±4.1] vs 12 [±1.4] months, P = 0.016). Interestingly, further analyses revealed that RASBs significantly improved OS only if used with erlotinib concurrently (34 [±13.8] vs 25 [±5] months, P = 0.002) and the OS benefit was more attributable to ARBs because only 4 patients received ACEI and erlotinib concurrently. However, the benefit of ARBs on OS disappeared in the multivariate analysis.The use of ARBs during erlotinib treatment may prolong OS of patients with metastatic NSCLC.

G-protein coupled receptors of the renin-angiotensin system: new targets against breast cancer?

G-protein coupled receptors (GPCRs) constitute the largest family of membrane receptors, with high potential for drug discovery. These receptors can be activated by a panel of different ligands including ions, hormones, small molecules, and vasoactive peptides. Among those, angiotensins [angiotensin II (AngII) and angiotensin 1–7] are the major biologically active products of the classical and alternative renin-angiotensin system (RAS). These peptides bind and activate three different subtypes of GPCRs, namely AT1, AT2, and Mas receptors, to regulate cardiovascular functions. Over the past decade, the contribution of several RAS components in tumorigenesis has emerged as a novel important concept, AngII being considered as harmful and Ang1–7 as protective against cancer. Development of selective ligands targeting each RAS receptor may provide novel and efficient targeted therapeutic strategies against cancer. In this review, we focus on breast cancer to summarize current knowledge on angiotensin receptors (AT1, AT2, and Mas), and discuss the potential use of angiotensin receptor agonists and antagonists in clinics.