Local angiotensin II-generation in human gastric cancer: correlation with tumor progression through the activation of ERK1/2, NF-kappaB and survivin

New insights into prostate Cancer from the renin-angiotensin-aldosterone system

Prostate cancer is among the most common malignancies found in men, with multifactorial changes occurring altogether to disrupt the pathophysiology of this gland. The Renin-Angiotensin-Aldosterone System (RAAS) is an extensively studied pathway that has newly attributed fundamental roles in cancer biology that impact cell growth, migration, metastasis, and death. These processes are significantly influenced by various components of the RAAS, including prorenin, AT1R, AT2R, and Ang 1-7/Mas receptors. Although the pathophysiology of prostate cancer is complex, targeting the RAAS shows promise as a therapeutic approach. RAAS dysregulation is evident in prostate cancer, and treatments traditionally used for cardiovascular diseases are being explored for cancer therapy. The RAAS pathway has significant effects on the formation of new blood vessels (angiogenesis), the spread of cancer cells to other parts of the body (metastasis), and cell proliferation. In this pathway, angiotensin II and its receptors have crucial functions. Angiotensin II stimulates angiogenesis and cell proliferation through the AT1R, whereas the AT2R has the opposite effect by inhibiting cell growth. Additional pathways involving ACE2/Ang 1-7/Mas also provide potential targets for therapeutic intervention, mitigating the impact of the traditional ACE/Angiotensin II/AT1R pathway. The components of the RAAS influence multiple signalling pathways, such as Androgen Receptor (AR), NF-κB, and PI3K/AKT/mTOR, which enhances our understanding of how it contributes to the progression of prostate cancer. This also provides new possibilities for therapeutic interventions.

MR imaging characteristics of different pathologic subtypes of esophageal carcinoma

OBJECTIVES

To describe the specific MRI characteristics of different pathologic subtypes of esophageal carcinoma (EC) METHODS: This prospective study included EC patients who underwent esophageal MRI and esophagectomy between April 2015 and October 2021. Pathomorphological characteristics of EC such as localized type (LT), ulcerative type (UT), protruding type (PT), and infiltrative type (IT) were assessed by two radiologists relying on the imaging characteristics of tumor, especially the specific imaging findings on the continuity of the mucosa overlying the tumor, the opposing mucosa, mucosa linear thickening, and transmural growth pattern. Intraclass correlation coefficients (ICC) were calculated for the consistency between two readers. The associations of imaging characteristics with different pathologic subtypes were assessed using multilogistic regression model (MLR).

RESULTS

A total of 201 patients were identified on histopathology with a high inter-reader agreement (ICC = 0.991). LT showed intact mucosa overlying the tumor. IT showed transmural growth pattern extending from the mucosa to the adventitia and a "sandwich" appearance. The remaining normal mucosa on the opposing side was linear and nodular in UT. PT showed correlation with T1 staging and grade 1; IT showed correlation with T3 staging and grades 2-3. Four MLR models showed high predictive performance on the test set with AUCs of 0.94 (LT), 0.87 (PT), 0.96 (IT), and 0.97 (UT), respectively, and the predictors that contributed most to the models matched the four specific characteristics.

CONCLUSIONS

Different pathologic subtypes of EC displayed specific MR imaging characteristics, which could help predict T staging and the degree of pathological differentiation.

CLINICAL RELEVANCE STATEMENT

Different pathologic subtypes of esophageal carcinoma displayed specific MR imaging characteristics, which correspond to differences in the degree of differentiation, T staging, and sensitivity to radiotherapy, and could also be one of the predictive factors of cause-specific survival and local progression-free rates.

KEY POINTS

Different types of EC had different characteristics on MR images. A total of 91/95 (96%) LTEC showed intact mucosa over the tumor, while masses or nodules are specific to PTEC; 21/27 (78%) ITEC showed a "sandwich" sign; and 33/35 (60%) UTEC showed linear and nodular opposing mucosa. In the association of tumor type with degree of differentiation and T staging, PTEC was predominantly associated with T1 and grade 1, and ITEC was associated with T3 and grades 2-3, while LTEC and UECT were likewise primarily linked with T2-3 and grades 2-3.

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.

Role of angiotensin II in aging

Aging is an inevitable progressive decline in physiological organ function that increases the chance of disease and death. The renin-angiotensin system (RAS) is involved in the regulation of vasoconstriction, fluid homeostasis, cell growth, fibrosis, inflammation, and oxidative stress. In recent years, unprecedented advancement has been made in the RAS study, particularly with the observation that angiotensin II (Ang II), the central product of the RAS, plays a significant role in aging and chronic disease burden with aging. Binding to its receptors (Ang II type 1 receptor - AT1R in particular), Ang II acts as a mediator in the aging process by increasing free radical production and, consequently, mitochondrial dysfunction and telomere attrition. In this review, we examine the physiological function of the RAS and reactive oxygen species (ROS) sources in detail, highlighting how Ang II amplifies or drives mitochondrial dysfunction and telomere attrition underlying each hallmark of aging and contributes to the development of aging and age-linked diseases. Accordingly, the Ang II/AT1R pathway opens a new preventive and therapeutic direction for delaying aging and reducing the incidence of age-related diseases in the future.

Increased risk of metastasis in patients with incidental use of renin-angiotensin system inhibitors: a retrospective analysis for multiple types of cancer based on electronic medical records

Renin-angiotensin system inhibitors have been shown to prevent cancer metastasis in experimental models, but there are limited data in clinical studies. We aimed to explore whether renin-angiotensin system inhibitors administered during the period of cancer resection can influence the subsequent development of metastasis by analyzing multiple individual types of primary cancers. A total of 4927 patients who had undergone resection of primary cancers at Kyushu University Hospital from 2009 to 2014 were enrolled and categorized into 3 groups based on the use of antihypertensive drugs: renin-angiotensin system inhibitors, other drugs, and none. Cumulative incidence functions of metastasis, treating death as a competing risk, were calculated, and the difference was examined among groups by Gray's test. Fine and Gray's model was employed to evaluate multivariate-adjusted hazards of incidental metastasis. In the multivariate-adjusted analysis, patients with skin and renal cancers showed statistically higher risks of metastasis with the use of renin-angiotensin system inhibitors (hazard ratio [95% confidence interval], 5.81 [1.07-31.57] and 4.24 [1.71-10.53], respectively). Regarding pancreatic cancer, patients treated with antihypertensive drugs other than renin-angiotensin system inhibitors had a significantly increased risk of metastasis (hazard ratio [95% confidence interval], 3.31 [1.43-7.69]). Future larger studies are needed to ascertain whether renin-angiotensin system inhibitors can increase the risk of metastasis in skin and renal cancers, focusing on specific tissue types and potential factors associated with renin-angiotensin system inhibitor use.

Angiotensin II Receptor Antagonist, Valsartan, Has Beneficial Effect in Lung Metastasis of Colorectal Cancer Treated with Fluorouracil

PURPOSE

Lung metastasis is the main cause of death in patients with colorectal carcinoma (CRC). Angiotensin II has been confirmed to facilitate cancer cell progression and metastasis. In this study, the possible anti-metastatic effects of an angiotensin II receptor type 1 (AT1R) antagonist, valsartan, have been investigated in an experimental CRC lung metastasis model.

METHODS

An animal CRC lung metastasis model was used, involving intravenous injection of CRC cells. The experimental groups included (1) control group; (2) 5-FU (5-fluorouracil) group (5 mg/kg/every other day; ip); (3) valsartan group (40 mg/kg/day; po); and (4) valsartan + 5-FU group (combination group; valsartan 40 mg/kg/day, oral gavage, and 5-FU 5 mg/kg/every other day; ip). After 11 days, macroscopic and histological evaluations of lung tissues have been done for evaluation of lung metastatic nodules. In addition, inflammatory and angiogenic markers and oxidative stress index were measured in lung tissue.

RESULTS

Our results showed that administration of valsartan especially in combination with 5-FU significantly reduced lung metastatic nodule and metastatic area (p < 0.05) in macroscopic and histological evaluations stained by hematoxylin-eosin. Measurement of inflammatory, angiogenic, and oxidative/antioxidative markers in lung tissue indicated that the level of IL-6, angiogenic markers (VEGF and VEGFR-1), and antioxidative markers significantly reduced in combination group (p < 0.05) while the MDA as a marker of oxidative stress increased (p < 0.05).

CONCLUSION

These results suggest that valsartan in combination with standard chemotherapeutic agents can have a synergistic effect in treatment of lung metastasis of CRC.

Angiotensin-converting Enzyme Inhibitors and Angiotensin Receptor Blockers as Potential Therapeutic Options for Pancreatic Cancer

The renin-angiotensin system (RAS) has been reported to have a role in carcinogenesis, and therefore it may be of value as a potential therapeutic target in inhibiting tumor growth. It has been shown that inhibition of RAS via angiotensin I-converting enzyme inhibitors (ACEIs) and angiotensin II type-1 receptor (ARBs) inhibitors may have a protective effect against several malignancies. Here, we provide an overview of the potential value of the RAS pathway and targeting via ACE/ARB inhibitors in pancreatic cancer. Whilst the potential role of RAS as a target for the treatment of pancreatic cancer has been reported, the use of candesartan with gemcitabine failed to improve outcomes in pancreatic cancer. Another study of 1-3 years using ARB was found to reduce the risk of pancreatic cancer. In line with these trials, others have demonstrated that the ARBs in combination with gemcitabine might improve clinical outcomes in patients with advanced pancreatic cancer. Prospective trials are warranted to investigate this hypothesis.

An Insight into GPCR and G-Proteins as Cancer Drivers

G-protein-coupled receptors (GPCRs) are the largest family of cell surface signaling receptors known to play a crucial role in various physiological functions, including tumor growth and metastasis. Various molecules such as hormones, lipids, peptides, and neurotransmitters activate GPCRs that enable the coupling of these receptors to highly specialized transducer proteins, called G-proteins, and initiate multiple signaling pathways. Integration of these intricate networks of signaling cascades leads to numerous biochemical responses involved in diverse pathophysiological activities, including cancer development. While several studies indicate the role of GPCRs in controlling various aspects of cancer progression such as tumor growth, invasion, migration, survival, and metastasis through its aberrant overexpression, mutations, or increased release of agonists, the explicit mechanisms of the involvement of GPCRs in cancer progression is still puzzling. This review provides an insight into the various responses mediated by GPCRs in the development of cancers, the molecular mechanisms involved and the novel pharmacological approaches currently preferred for the treatment of cancer. Thus, these findings extend the knowledge of GPCRs in cancer cells and help in the identification of therapeutics for cancer patients.

AGTR1 Inhibits the Progression of Lung Adenocarcinoma

Purpose

The occurrence and development of lung adenocarcinoma (LUAD) are related to many factors. Multiple researches showed that the renin-angiotensin system (RAS) plays an important role in lung cancer. This research mainly focuses on angiotensin II receptor 1 (AT1R) encoding gene AGTR1, an important part of the RAS.

Methods

We comprehensively evaluated the expression of AGTR1 in pan-cancer based on RNA sequencing data obtained from The Cancer Genome Atlas (TCGA). We explored the correlation of AGTR1 with clinicopathological features, prognosis and tumor microenvironment in LUAD. We also explored the mechanism through enrichment analysis and verified it with cell lines and tissue samples.

Results

We found that AGTR1 was less expressed in most tumors and related to prognosis based on the TCGA database. To further explore its mechanism, we mainly focused on LUAD. Combined with the verification results in the GEO database, AGTR1 was associated with a better prognosis in LUAD. High expression of AGTR1 was associated with less lymph node metastasis (P=0.007) and MET mutation (P=0.019). High expression of AGTR1 was related to the anti-tumor immune microenvironment with high infiltration of B cells, myeloid dendritic cells, monocytes, and low infiltration of myeloid-derived suppressor cells (all P<0.05). Enrichment analysis and in vitro verification results showed that AGTR1 was likely to play a role in LUAD through the PI3K/AKT3 pathway. Finally, we verified the above results through tissue samples and the construction of AGTR1 overexpressing cells.

Conclusion

AGTR1 inhibits the progression of lung adenocarcinoma through the PI3K/AKT3 pathway.

Roles of G Protein-Coupled Receptors (GPCRs) in Gastrointestinal Cancers: Focus on Sphingosine 1-Shosphate Receptors, Angiotensin II Receptors, and Estrogen-Related GPCRs

It is well established that gastrointestinal (GI) cancers are common and devastating diseases around the world. Despite the significant progress that has been made in the treatment of GI cancers, the mortality rates remain high, indicating a real need to explore the complex pathogenesis and develop more effective therapeutics for GI cancers. G protein-coupled receptors (GPCRs) are critical signaling molecules involved in various biological processes including cell growth, proliferation, and death, as well as immune responses and inflammation regulation. Substantial evidence has demonstrated crucial roles of GPCRs in the development of GI cancers, which provided an impetus for further research regarding the pathophysiological mechanisms and drug discovery of GI cancers. In this review, we mainly discuss the roles of sphingosine 1-phosphate receptors (S1PRs), angiotensin II receptors, estrogen-related GPCRs, and some other important GPCRs in the development of colorectal, gastric, and esophageal cancer, and explore the potential of GPCRs as therapeutic targets.

Renin-Angiotensin-Aldosterone System and Immunomodulation: A State-of-the-Art Review

The renin–angiotensin system (RAS) has long been described in the field of cardiovascular physiology as the main player in blood pressure homeostasis. However, other effects have since been described, and include proliferation, fibrosis, and inflammation. To illustrate the immunomodulatory properties of the RAS, we chose three distinct fields in which RAS may play a critical role and be the subject of specific treatments. In oncology, RAS hyperactivation has been associated with tumor migration, survival, cell proliferation, and angiogenesis; preliminary data showed promise of the benefit of RAS blockers in patients treated for certain types of cancer. In intensive care medicine, vasoplegic shock has been associated with severe macro- and microcirculatory imbalance. A relative insufficiency in angiotensin II (AngII) was associated to lethal outcomes and synthetic AngII has been suggested as a specific treatment in these cases. Finally, in solid organ transplantation, both AngI and AngII have been associated with increased rejection events, with a regional specificity in the RAS activity. These elements emphasize the complexity of the direct and indirect interactions of RAS with immunomodulatory pathways and warrant further research in the field.

Protective Effects of Irbesartan, an Angiotensin Receptor Blocker with PPARγ Agonistic Activity, against Estradiol Benzoate-Induced Endometrial Hyperplasia and Atypia in Female Rats via Modulation of TNFα/Survivin Pathway

Endometrial hyperplasia (EH) is a common gynecological problem and may progress to carcinoma. Early detection and management of EH are mandatory for the prevention of endometrial cancer. Activation of the renin-angiotensin system and angiotensin II signaling are involved in the progression of precancerous and cancerous lesions. However, no studies have evaluated the role of this system in estradiol benzoate (EB)-induced EH and atypia. Irbesartan (IRB), an angiotensin II receptor blocker with peroxisome proliferator-activated receptor gamma (PPARγ) agonistic activity was administered (30 mg/kg/d) in EB-treated (60 µg/100 g bodyweight, intramuscularly, three times per week) or untreated rats for 4 weeks. Uterine weight changes, malondialdehyde, superoxide dismutase (SOD), tumor necrosis factor-alpha (TNFα), survivin, cleaved caspase 3, interleukin-10 (IL10), and PPARγ were measured in addition to undergoing histopathological examination. Results showed that EB-induced EH and atypia significantly increased the uterine body weight, malondialdehyde, TNFα, and survivin, accompanied with significantly decreased SOD, cleaved caspase 3, IL10, and PPARγ, with typical histopathological changes of EH and atypia. Coadministration of IRB significantly prevented EB-induced biochemical and histopathological changes. The protective effects of IRB may be attributed to its anti-inflammatory and antioxidant properties, reduction of survivin, and increased levels of cleaved caspase 3.

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.

Renin angiotensin system genes are biomarkers for personalized treatment of acute myeloid leukemia with Doxorubicin as well as etoposide

Despite the availability of various treatment protocols, response to therapy in patients with Acute Myeloid Leukemia (AML) remains largely unpredictable. Transcriptomic profiling studies have thus far revealed the presence of molecular subtypes of AML that are not accounted for by standard clinical parameters or by routinely used biomarkers. Such molecular subtypes of AML are predicted to vary in response to chemotherapy or targeted therapy. The Renin-Angiotensin System (RAS) is an important group of proteins that play a critical role in regulating blood pressure, vascular resistance and fluid/electrolyte balance. RAS pathway genes are also known to be present locally in tissues such as the bone marrow, where they play an important role in leukemic hematopoiesis. In this study, we asked if the RAS genes could be utilized to predict drug responses in patients with AML. We show that the combined in silico analysis of up to five RAS genes can reliably predict sensitivity to Doxorubicin as well as Etoposide in AML. The same genes could also predict sensitivity to Doxorubicin when tested in vitro. Additionally, gene set enrichment analysis revealed enrichment of TNF-alpha and type-I IFN response genes among sensitive, and TGF-beta and fibronectin related genes in resistant cancer cells. However, this does not seem to reflect an epithelial to mesenchymal transition per se. We also identified that RAS genes can stratify patients with AML into subtypes with distinct prognosis. Together, our results demonstrate that genes present in RAS are biomarkers for drug sensitivity and the prognostication of AML.

Elucidating the Association Between the Upregulation of Angiotensin Type 1-Receptors and the Development of Gastrointestinal Malignancies

The renin-angiotensin system (RAS) is a major regulator of body fluid hemostasis and blood pressure. Angiotensin type 1 receptors (AT1R) are one of the major components of this system and are widely expressed in different organs, including the gastrointestinal (GI) system. Very little known about the physiological roles of AT1R in GI tract but evidence has reported that local AT1Rs are upregulated in pathological conditions like GI malignancies and play role in stimulation of signaling pathways associated with GI cancers progression. AT1Rs axes signaling in tumor microenvironments stimulate inflammation and facilitate vascularization around the tumor cell to display invasive behavior. AT1Rs in stroma cells promote tumor-associated angiogenesis by upregulated of vessel endothelial growth factor (VEGF). Also, AT1Rs by the activation of molecular mechanisms such as PI3/Akt/NF-κB pathways increase the invasion of tumor cells. Experimental and clinical studies have reported that AT1R antagonists have beneficial influences by increasing the survival of patients with GI malignancies and reduction in the proliferation of GI cancer cell lines in vitro, and the growth and metastasis of tumors in vivo, therefore, AT1Rs antagonist have the potential for future anticancer strategies. This review focuses on the pathological roles of AT1Rs in GI malignancies.

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.

Therapeutic Targeting of Cancer Stem Cells via Modulation of the Renin-Angiotensin System

Cancer stem cells (CSCs) are proposed to be the cells that initiate tumorigenesis and maintain tumor development due to their self-renewal and multipotency properties. CSCs have been identified in many cancer types and are thought to be responsible for treatment resistance, metastasis, and recurrence. As such, targeting CSCs specifically should result in durable cancer treatment. One potential option for targeting CSCs is by manipulation of the renin-angiotensin system (RAS) and pathways that converge on the RAS with numerous inexpensive medications currently in common clinical use. In addition to its crucial role in cardiovascular and body fluid homeostasis, the RAS is vital for stem cell maintenance and differentiation and plays a role in tumorigenesis and cancer prevention, suggesting that these roles may converge and result in modulation of CSC function by the RAS. In support of this, components of the RAS have been shown to be expressed in many cancer types and have been more recently localized to the CSCs in some tumors. Given these roles of the RAS in tumor development, clinical trials using RAS inhibitors either singly or in combination with other therapies are underway in different cancer types. This review outlines the roles of the RAS, with respect to CSCs, and suggests that the presence of components of the RAS in CSCs could offer an avenue for therapeutic targeting using RAS modulators. Due to the nature of the RAS and its crosstalk with numerous other signaling pathways, a systems approach using traditional RAS inhibitors in combination with inhibitors of bypass loops of the RAS and other signaling pathways that converge on the RAS may offer a novel therapeutic approach to cancer treatment.

Telmisartan Inhibits Cell Proliferation and Tumor Growth of Esophageal Squamous Cell Carcinoma by Inducing S-Phase Arrest In Vitro and In Vivo

Esophageal squamous cell carcinoma (ESCC) is the most common primary esophageal malignancy. Telmisartan, an angiotensin II type 1 (AT1) receptor blocker (ARB) and a widely used antihypertensive, has been shown to inhibit proliferation of various cancer types. This study evaluated the effects of telmisartan on human ESCC cell proliferation in vitro and in vivo and sought to identify the microRNAs (miRNAs) involved in these antitumor effects. We examined the effects of telmisartan on three human ESCC cell lines (KYSE150, KYSE180, and KYSE850). Telmisartan inhibited proliferation of these three cell lines by inducing S-phase arrest, which was accompanied by decreased expression of cyclin A2, cyclin-dependent kinase 2, and other cell cycle-related proteins. Additionally, telmisartan reduced levels of phosphorylated ErbB3 and thrombospondin-1 in KYSE180 cells. Furthermore, expression of miRNAs was remarkably altered by telmisartan in vitro. Telmisartan also inhibited tumor growth in vivo in a xenograft mouse model. In conclusion, telmisartan inhibited cell proliferation and tumor growth in ESCC cells by inducing cell-cycle arrest.

Multidisciplinary therapy for scirrhous gastric cancer: a retrospective analysis and proposal of new treatment strategy

Background

Scirrhous gastric cancer (SGC) is highly invasive and metastatic because of its interactions with stromal cells, such as fibroblasts and macrophages, and extracellular matrix, leading to a higher incidence of peritoneal metastasis (PM) than other gastric cancers (GCs). Taxane-based intraperitoneal chemotherapy (IPC) is a promising therapy for PM. We retrospectively analyzed outcomes of multidisciplinary therapies that included IPC for SGC.

Patients and therapy

Of 1,679 GC patients treated between 1990 and 2012, we analyzed 119 patients who underwent multidisciplinary therapy for SGC. Patients without PM received gastrectomy with lymphadenectomy and resection of involved adjacent organs followed by intraoperative IPC using cisplatin. Patients with PM received chemotherapy using fluorouracil, with or without methotrexate plus IPC using cisplatin before 2000, and S-1 plus IPC using paclitaxel or docetaxel since 2000.

Results

Of the 119 patients, 73 (61%) had PM and 63 (53%) had positive peritoneal lavage cytology. Of the 89 gastrectomy patients, 30 (34%) had macroscopic residual tumors (R2). Of the patients treated since 2000, 66 (100%) received S-1 plus taxanes and 44 patients (67%) received taxane-based IPC. Median survival time was significantly longer in the post-2000 group (22.8 months) than in the pre-2000 group (9.5 months). In univariate analysis, lavage cytology, PM, taxane-based IPC, gastrectomy, and R2 resection were significant prognostic factors. However, only R2 resection was an independent prognostic factor in multivariate analysis (hazard ratio: 5.53, 95% CI: 2.05–14.93).

Conclusion

As use of taxane-based IPC is not an independent prognostic factor, new multidisciplinary therapies are necessary to avoid R2 resections.

AngII induces HepG2 cells to activate epithelial-mesenchymal transition

The present study aimed to determine whether HepG2 can induce epithelial-mesenchymal transition (EMT) via angiotensin II (AngII) simulation. The expression levels of EMT markers vimentin and E-cadherin in cancer tissues and adjacent tissues of patients with hepatocellular carcinoma (HCC) were detected by immunohistochemistry. In addition, HepG2 cells were stimulated with AngII, and the gene and protein expression levels of vimentin and E-cadherin were measured by reverse transcription-quantitative polymerase chain reaction and western blot analyses, respectively, whereas cell migration and invasion were assessed using Transwell assays. The AngII inhibitor Ang1-7 and the Ang1-7 inhibitor A779 were added to the system to further evaluate AngII-induced EMT. Compared with that in normal tissue, the expression level of vimentin in HCC tissue was increased, whereas that of E-cadherin was decreased. EMT occurred 48 h following AngII stimulation. The transcription level of E-cadherin in HepG2 cells was decreased, whereas that of vimentin was increased. In addition, the migration and invasion abilities of the cells were increased simultaneously. Ang1-7 partly inhibited AngII-induced EMT. When stimulated at an appropriate time, HepG2 cells have the ability to undergo EMT.

The angiotensin II type 1 receptor antagonist telmisartan inhibits cell proliferation and tumor growth of esophageal adenocarcinoma via the AMPKα/mTOR pathway in vitro and in vivo

Telmisartan, a widely used antihypertensive drug, is an angiotensin II type 1 (AT1) receptor blocker (ARB). This drug inhibits cancer cell proliferation, but the underlying mechanisms in various cancers, including esophageal cancer, remain unknown. The aim of the present study was to evaluate the effects of telmisartan on human esophageal cancer cell proliferation in vitro and in vivo. We assessed the effects of telmisartan on human esophageal adenocarcinoma (EAC) cells using the cell lines OE19, OE33, and SKGT-4. Telmisartan inhibited the proliferation of these three cell lines via blockade of the G₀ to G₁ cell cycle transition. This blockade was accompanied by a strong decrease in cyclin D1, cyclin E, and other cell cycle-related proteins. Notably, the AMP-activated protein kinase (AMPK) pathway, a fuel sensor signaling pathway, was enhanced by telmisartan. Compound C, which inhibits the two catalytic subunits of AMPK, enhanced the expression of cyclin E, leading to G₀/G₁ arrest in human EAC cells. In addition, telmisartan reduced the phosphorylation of epidermal growth factor receptor (p-EGFR) and ERBB2 in vitro. In our in vivo study, intraperitoneal injection of telmisartan led to a 73.2% reduction in tumor growth in mice bearing xenografts derived from OE19 cells. Furthermore, miRNA expression was significantly altered by telmisartan in vitro and in vivo. In conclusion, telmisartan suppressed human EAC cell proliferation and tumor growth by inducing cell cycle arrest via the AMPK/mTOR pathway.

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 receptor blocker use and gastro-oesophageal cancer survival: a population-based cohort study

BACKGROUND

Angiotensin receptor blockers (ARBs; including candesartan, losartan, olmesartan and valsartan) are widely used to treat hypertension, heart failure and diabetic neuropathy. There is considerable pre-clinical evidence that ARBs can reduce cancer progression, particularly for gastric cancer. Despite this, epidemiological studies have yet to assess the impact of ARB use on gastro-oesophageal cancer survival.

AIM

To investigate the association between post-diagnosis ARB use and gastro-oesophageal cancer survival.

METHODS

We selected a cohort of patients with newly-diagnosed gastro-oesophageal cancer between 1998 and 2012 from English cancer registries. We linked to prescription and clinical records from the Clinical Practice Research Datalink, and to death records from the Office for National Statistics. We used time-dependant Cox-regression models to calculate hazard ratios (HRs) comparing gastro-oesophageal cancer-specific mortality between post-diagnosis ARB users and non-users, after adjusting for demographics, comorbidities and post-diagnosis aspirin or statin use.

RESULTS

Our cohort included 5124 gastro-oesophageal cancer patients, of which 360 used ARBs, and 3345 died due to their gastro-oesophageal cancer during follow-up. After adjustment, ARB users had moderately lower risk of gastro-oesophageal cancer mortality than the non-users (HR = 0.83, 95% CI 0.71-0.98). There was evidence of a dose-response relationship with the lowest HRs observed among patients receiving at least 2 years of prescriptions (HR = 0.42, 95% CI 0.25-0.72).

CONCLUSIONS

In this large population-based gastro-oesophageal cancer cohort, we found moderately reduced cancer-specific mortality among ARB users. However, confirmation in further independent epidemiological studies with sufficient staging information is required.

Angiotensin receptor blocker telmisartan inhibits cell proliferation and tumor growth of cholangiocarcinoma through cell cycle arrest

Cholangiocarcinoma (CCA) is at an advanced stage at the time of its diagnosis, and developing a more effective treatment of CCA would be desirable. Angiotensin II type 1 (AT1) receptor blocker (ARB), telmisartan may inhibit cancer cell proliferation, but the mechanisms by which telmisartan affects various cancers remain unknown. In this study, we evaluated the effects of telmisartan on human CCA cells and to assess the expression of microRNAs (miRNAs). We studied the effects of telmisartan on CCA cells using two cell lines, HuCCT-1 and TFK-1. In our experiments, telmisartan inhibited the proliferation of HuCCT-1 and TFK-1 cells. Additionally, telmisartan induced G0/G1 cell cycle arrest via blockade of the G0 to G1 cell cycle transition. Notably, telmisartan did not induce apoptosis in HuCCT-1 cells. This blockade was accompanied by a strong decrease in cell cycle-related protein, especially G1 cyclin, cyclin D1, and its catalytic subumits, Cdk4 and Cdk6. Telmisartan reduced the phosphorylation of EGFR (p-EGFR) and TIMP-1 by using p-RTK and angiogenesis array. Furthermore, miRNA expression was markedly altered by telmisartan in HuCCT-1. Telmisartan inhibits tumor growth in CCA xenograft model in vivo. In conclusion, telmisartan was shown to inhibit human CCA cell proliferation by inducing cell cycle arrest.

Telmisartan inhibits hepatocellular carcinoma cell proliferation in vitro by inducing cell cycle arrest

Hepatocellular carcinoma (HCC) is the most common primary malignancy of the liver and the third leading cause of cancer-related death. Telmisartan, a widely used antihypertensive drug, is an angiotensin II type 1 (AT1) receptor blocker (ARB) that might inhibit cancer cell proliferation, but the mechanisms through which telmisartan affects various cancers remain unknown. The aim of the present study was to evaluate the effects of telmisartan on human HCC and to assess the expression of microRNAs (miRNAs). We studied the effects of telmisartan on HCC cells using the HLF, HLE, HepG2, HuH-7 and PLC/PRF/5 cell lines. In our experiments, telmisartan inhibited the proliferation of HLF, HLE and HepG2 cells, which represent poorly differentiated types of HCC cells. However, HuH-7 and PLC/PRF/5 cells, which represent well-differentiated types of HCC cells, were not sensitive to telmisartan. Telmisartan induced G₀/G₁ cell cycle arrest of HLF cells by inhibiting the G₀-to-G₁ cell cycle transition. This blockade was accompanied by a marked decrease in the levels of cyclin D1, cyclin E and other cell cycle-related proteins. Notably, the activity of the AMP-activated protein kinase (AMPK) pathway was increased, and the mammalian target of rapamycin (mTOR) pathway was inhibited by telmisartan treatment. Additionally, telmisartan increased the level of caspase-cleaved cytokeratin 18 (cCK18), partially contributed to the induction of apoptosis in HLF cells and reduced the phosphorylation of ErbB3 in HLF cells. Furthermore, miRNA expression was markedly altered by telmisartan in vitro. In conclusion, telmisartan inhibits human HCC cell proliferation by inducing cell cycle arrest.

A precision-guided MWNT mediated reawakening the sunk synergy in RAS for anti-angiogenesis lung cancer therapy

Multi-walled carbon nanotube (MWNT) with its versatility has exhibited tremendous superiority in drug delivery. Despite plenty of researches on MWNT based delivery systems, precision-guided assistances to maximize their profitable properties are still lacking in substantive progress. We developed here a dual-targeting and co-delivery system based on MWNT for antiangiogenesis therapy in lung cancer which aimed at renin-angiotensin system (RAS) dysregulation by synergistically conducting angiotensin II type 1 receptor (AT₁R) and type 2 receptor (AT₂R) pathway. In this work, iRGD peptide connected to polyethyleneimine (PEI) was linked to MWNT skeleton, accompanying with candesartan (CD) conjugated to MWNT mediated by cystamine (SS). The functionalized MWNT is assembled with plasmid AT₂ (pAT₂) to form iRGD-PEI-MWNT-SS-CD/pAT₂ complexes. iRGD and CD act as pilots for complexes to dually target symbolic ανβ3-integrin and AT₁R both overexpressed on tumor angiogenic endothelium and lung cancer cell. CD as chemotherapy showed synergistic downregulation of VEGF when combining of pAT₂ and efficiently inhibited angiogenesis. iRGD-PEI-MWNT-SS-CD/pAT₂ complexes greatly appreciated drug activities by changing drug distribution and exhibited remarkable tumor growth suppression in A549 xenograft nude mice. Our work presents that such dual-targeting strategy highly improves the delivery performance of MWNT and open a new avenue for RAS related lung cancer therapy.

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.

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.

[Oncology-related issues of angiotensin-receptor blockers]

Recently controversial data emerged regarding the cancer inducing activity of angiotensin-receptor blockers. There may be several reasons which may explain the controversial data published in the scientific literature including wrong trial design or misinterpretation of data. Considering the large number of patients receiving treatment for hypertension, it is essential to have a clear view of the cancer-related safety of these drugs. This paper tries to give an overview on this issue based on data available in the literature. According to our present knowledge, angiotensin-receptor blockers exert more likely anticancer activity rather than carcinogenesis inducing effect. In fact, some oncologic trials point to this direction, because angiotensin-receptor blockers are suggested as co-treatment to chemotherapy in cases of pancreatic, oesophageal and gastric cancers.

Lack of an association between angiotensin receptor blocker based therapy and increased risk of cancer: evidence from large observational studies

Background

A previous meta-analysis of randomized controlled studies that were not designed to investigate cancer as a primary outcome suggested that ARB-based therapy is associated with increased risk of cancer; however, results of recent observational studies considering the association have been contradictory. This study sought to evaluate the association between angiotensin receptor blocker (ARB)-based therapy and risk of cancer by conducting a meta-analysis of observational studies.

Methods

Relevant articles published before February 2014 were identified by searching PubMed and the Cochrane Library. Pooled relative risks (RRs) were determined using a random effects model and were used to assess the strength of association between use of ARB-based therapy and risk of cancer.

Results

Six retrospective cohort studies involving a total of 3,827,109 participants and four case-control studies involving a total of 193,029 cases were included. The present study found that ARB-based therapy was not significantly associated with an increased risk of cancer (RR = 0.87, 95%CI: [0.75, 1.01]). However, an analysis including only cohort studies suggested a significantly decreased risk of cancer among individuals with any history of ARB use as compared to those with no history of ARB use (RR = 0.80, 95%CI: [0.55, 0.95]); no significant association was found between ARB use and risk of cancer when the case-control studies were separately considered (RR = 1.03, 95%CI: [0.93, 1.13]). Subgroup analyses showed that use of ARB-based therapy was associated with decreased risk of lung cancer (RR = 0.81, 95%CI: [0.69, 0.94]); however, no significant associations were found with the other cancer sites investigated. Furthermore, no association was observed upon adjustment by type of ARB drug. No publication bias was detected.

Conclusion

Overall, ARB-based therapy was not associated with increased risk of cancer. However, its use may be related to decreased incidence of lung cancer; this finding should be considered carefully and confirmed with further studies.

Angiotensin II: immunohistochemical study in Sardinian pterygium

The Angiotensin II (Ang II) is the principal effector peptide of the RAS system. It has a pleiotropic effect and, beside its physiological role, it has the property to stimulate angiogenesis and activate multiple signalling pathways related to cell proliferation. The purpose of the study was to determinate the Ang II expression and localization in Sardinian pterygium and normal conjunctiva by immunohistochemistry, and its possible involvement in the development and progression of the disease. Twenty-three pterygiums and eleven normal conjunctiva specimens obtained from Sardinian patients, were processed for paraffin embedding and assessed for the immunohistochemi-cal revelation of Ang II. Significant Ang II expression was identified in pterygium and conjunctiva. Particularly, thirteen pterygium specimens (n=13) displayed exclusively moderate to strong nuclear staining; some specimens (n=5) showed exclusively a moderate cytoplasmic immunoreactivity, and few specimens (n=2) displayed moderate to strong immunoreactivity in both cytoplasm and nucleus. Only 3 specimens were negative. Statistical significance difference in respect of nuclear and cytoplasmic localization was observed between normal conjunctiva and pterygium (P=0.020). The results showed a predominant intranuclear localization of Ang II in pterygium epithelial cells, in spite of conjunctiva that mainly showed cytoplasmic localization. These findings suggest a possible role for Ang II in the development and/or progression of pterygium mediated by the activation of local RAS system.

Angiotensin II promotes the progression of human gastric cancer

The renin-angiotensin system (RAS) plays an important role in cardiovascular homeostasis, carcinogenesis‑related angiogenesis and cell proliferation. The present study was undertaken to determine the expression of angiotensin (Ang) II, Ang II type 1 and 2 receptors (AT1R and AT2R), and the activity of the angiotensin‑converting enzyme (ACE) in gastric cancer tissue. The study further examined the roles of Ang II in the growth of gastric cancer cells in nude mice and in the migration and proliferation of MKN45 human gastric cancer cells. Gastric cancer tissue samples were obtained from gastric cancer patients. The levels of Ang II, AT1R and AT2R, as well as ACE activity were increased in tissues from gastric cancer patients compared to healthy tissues. A gastric cancer model was established by intraperitoneally injecting MKN45 human gastric cancer cells in nude mice, intraperitoneally injecting Ang II and measuring the tumor size every two days. Ang II treatment caused an increase in the size and weight of the tumor mass in nude mice, whereas the AT1R antagonist losartan significantly inhibited the size and weight of the tumor. While Ang II enhanced the migratory and proliferative rate of MKN45 human gastric cancer cells, these were significantly reduced following treatment with losartan. These results indicate that RAS is activated in gastric cancer patients and Ang II promotes the progression of gastric cancer in nude mice, as well as the migration and proliferation of MKN45 human gastric cancer cells.

[Angiotensin-2 type 1 receptors (AT1R) and cancers]

Recently, several meta-analysis suggested an increased risk of cancers linked to the use of antagonists of angiotensin-2 receptors or inhibitors of angiotensinogen converting enzyme. The results of epidemiological studies are conflicting. Meta-analysis as well as retrospective studies are not reliable and biased, since they have never been designed to explore any pro- or antitumoral effect. We lack of prospective studies that could take off the doubt on these drugs. Nevertheless, all experimental researches pointed out potent antitumoral properties. Indeed, direct antiproliferative and neo-angiogenic inhibition have been described on tumor cell cultures as well as on animal models. Moreover, we are convinced that the use of antagonists of angiotensin-2 receptors and inhibitors of angiotensinogen converting enzyme may be then of clinical use in the near future in association with classical antitumor drugs. In this review, we proposed to explore these data by a thorough analysis of recent literature associating epidemiological and experimental studies.

A modern understanding of the traditional and nontraditional biological functions of angiotensin-converting enzyme

Angiotensin-converting enzyme (ACE) is a zinc-dependent peptidase responsible for converting angiotensin I into the vasoconstrictor angiotensin II. However, ACE is a relatively nonspecific peptidase that is capable of cleaving a wide range of substrates. Because of this, ACE and its peptide substrates and products affect many physiologic processes, including blood pressure control, hematopoiesis, reproduction, renal development, renal function, and the immune response. The defining feature of ACE is that it is composed of two homologous and independently catalytic domains, the result of an ancient gene duplication, and ACE-like genes are widely distributed in nature. The two ACE catalytic domains contribute to the wide substrate diversity of ACE and, by extension, the physiologic impact of the enzyme. Several studies suggest that the two catalytic domains have different biologic functions. Recently, the X-ray crystal structure of ACE has elucidated some of the structural differences between the two ACE domains. This is important now that ACE domain-specific inhibitors have been synthesized and characterized. Once widely available, these reagents will undoubtedly be powerful tools for probing the physiologic actions of each ACE domain. In turn, this knowledge should allow clinicians to envision new therapies for diseases not currently treated with ACE inhibitors.

The roles of beta-adrenergic receptors in tumorigenesis and the possible use of beta-adrenergic blockers for cancer treatment: possible genetic and cell-signaling mechanisms

Cancer is the leading cause of death in the USA, and the incidence of cancer increases dramatically with age. Beta-adrenergic blockers appear to have a beneficial clinical effect in cancer patients. In this paper, we review the evidence of an association between β-adrenergic blockade and cancer. Genetic studies have provided the opportunity to determine which proteins link β-adrenergic blockade to cancer pathology. In particular, this link involves the major histocompatibility complex class II molecules, the renin-angiotensin system, transcription factor nuclear factor-kappa-light-chain-enhancer of activated B cells, poly(ADP-ribose) polymerase-1, vascular endothelial growth factor, and the reduced form of nicotinamide adenine dinucleotide phosphate oxidase. Beta-adrenergic blockers also exert anticancer effects through non-genomic factors, including matrix metalloproteinase, mitogen-activated protein kinase pathways, prostaglandins, cyclooxygenase-2, oxidative stress, and nitric oxide synthase. In conclusion, β-adrenergic blockade may play a beneficial role in cancer treatment. Additional investigations that examine β-adrenergic blockers as cancer therapeutics are required to further elucidate this role.

Angiotensin II facilitates breast cancer cell migration and metastasis

Breast cancer metastasis is a leading cause of death by malignancy in women worldwide. Efforts are being made to further characterize the rate-limiting steps of cancer metastasis, i.e. extravasation of circulating tumor cells and colonization of secondary organs. In this study, we investigated whether angiotensin II, a major vasoactive peptide both produced locally and released in the bloodstream, may trigger activating signals that contribute to cancer cell extravasation and metastasis. We used an experimental in vivo model of cancer metastasis in which bioluminescent breast tumor cells (D3H2LN) were injected intra-cardiacally into nude mice in order to recapitulate the late and essential steps of metastatic dissemination. Real-time intravital imaging studies revealed that angiotensin II accelerates the formation of metastatic foci at secondary sites. Pre-treatment of cancer cells with the peptide increases the number of mice with metastases, as well as the number and size of metastases per mouse. In vitro, angiotensin II contributes to each sequential step of cancer metastasis by promoting cancer cell adhesion to endothelial cells, trans-endothelial migration and tumor cell migration across extracellular matrix. At the molecular level, a total of 102 genes differentially expressed following angiotensin II pre-treatment were identified by comparative DNA microarray. Angiotensin II regulates two groups of connected genes related to its precursor angiotensinogen. Among those, up-regulated MMP2/MMP9 and ICAM1 stand at the crossroad of a network of genes involved in cell adhesion, migration and invasion. Our data suggest that targeting angiotensin II production or action may represent a valuable therapeutic option to prevent metastatic progression of invasive breast tumors.

Role of renin-angiotensin system in gastric oncogenesis

The renin-angiotensin system (RAS) plays an important role not only in homeostasis but also in carcinogenesis. Recent epidemiological studies suggest that hypertensive patients with upregulated systemic RAS functions are at a significantly increased risk for the subsequent development of cancers with poor outcomes, and moreover that RAS inhibitors reduce tumor development, progression, and metastasis. Notably, Helicobacter pylori infection, one of the major predictors of gastric carcinogenesis, generally leads to RAS component overexpression, as exemplified by that of angiotensin I, angiotensin II, angiotensin I converting enzyme and angiotensin II receptor. Gastric mucosal RAS expression gradually increases with time after H. pylori infection with respect to the severity of inflammatory cell infiltration. Gastric carcinogenic potential is therefore considered to relate to RAS component expression levels and activities. This hypothesis is supported by findings that RAS genotypic variation can lead to high component expression levels (e.g. angiotensin I converting enzyme, chymase and angiotensinogen), and thereby increase the risk of development of gastric cancer. Thus, the RAS may be potently associated with the pathogenesis of H. pylori-related gastric carcinogenesis, and RAS inhibitors may provide tools for specifically preventing this disease.

Review article: the pathophysiological roles of the renin-angiotensin system in the gastrointestinal tract

BACKGROUND

The renin-angiotensin system (RAS) is a homeostatic pathway widely known to regulate cardiovascular and renal physiology; however, little is known about its influence in gastrointestinal tissues.

AIM

To elicit the anatomical distribution and physiological significance of the components of the RAS in the gastrointestinal tract.

METHODS

An extensive online literature review including Pubmed and Medline.

RESULTS

There is evidence for RAS involvement in gastrointestinal physiology and pathophysiology, with all the components required for autonomous regulation identified throughout the gastrointestinal tract. The RAS is implicated in the regulation of glucose, amino acid, fluid and electrolyte absorption and secretion, motility, inflammation, blood flow and possibly malignant disease within the gastrointestinal tract. Animal studies investigating the effects of RAS blockade in a range of conditions including inflammatory bowel disease, functional gut disorders, gastrointestinal malignancy and even intestinal ischaemia have been encouraging to date. Given the ready availability of drugs that modify the RAS and their excellent safety profile, an opportunity exists for investigation of their possible therapeutic role in a variety of human gastrointestinal diseases.

CONCLUSIONS

The gastrointestinal renin-angiotensin system appears to be intricately involved in a number of physiological processes, and provides a possible target for novel investigative and therapeutic approaches.

Regulation of monocyte chemoattractant protein-1 through angiotensin II type 1 receptor in prostate cancer

Monocyte chemoattractant protein-1 (MCP-1/CCL2) is reported to contribute to tumor progression and is regulated by the renin-angiotensin system in hypertensive disease. In this study, we investigated the clinical outcome of MCP-1 expression in patients with prostate cancer (CaP) and the regulation of MCP-1 through angiotensin II (AngII) type 1 receptor (AT1R) in CaP. Specimens were obtained from 138 CaP patients and analyzed by immunostaining for both MCP-1 and macrophages. We investigated the regulation of MCP-1 expression through AT1R both in vivo and in vitro using three human prostate cancer cell lines: LNCaP, C4-2, and C4-2AT6. Specimens with a high Gleason score (≥7) and a high pathological classification (≤pT3), and those with castration-resistant prostate cancer showed significantly higher MCP-1 expression and higher macrophage infiltration than low malignant potential CaP. High MCP-1 expression in CaP correlated significantly with high prostate-specific antigen (PSA) recurrence rates. AngII induced significantly higher MCP-1 levels in C4-2AT6 than in LNCaP, whereas AT1R blockade (ARB) inhibited MCP-1 production via the inhibition of the PI3K/Akt pathway in C4-2AT6. ARB also significantly suppressed MCP-1 expression in C4-2AT6 tumors. Our study is the first to demonstrate that both high MCP-1 expression and high macrophage infiltration in CaP specimens correlate with a high PSA recurrence rate and that ARB inhibits MCP-1 expression through the PI3K/Akt pathway and blocks macrophage infiltration in castration-resistant prostate cancer.

Differential gene expression profiling of human bone marrow-derived mesenchymal stem cells during adipogenic development

BACKGROUND

Adipogenesis is the developmental process by which mesenchymal stem cells (MSC) differentiate into pre-adipocytes and adipocytes. The aim of the study was to analyze the developmental strategies of human bone marrow MSC developing into adipocytes over a defined time scale. Here we were particularly interested in differentially expressed transcription factors and biochemical pathways. We studied genome-wide gene expression profiling of human MSC based on an adipogenic differentiation experiment with five different time points (day 0, 1, 3, 7 and 17), which was designed and performed in reference to human fat tissue. For data processing and selection of adipogenic candidate genes, we used the online database SiPaGene for Affymetrix microarray expression data.

RESULTS

The mesenchymal stem cell character of human MSC cultures was proven by cell morphology, by flow cytometry analysis and by the ability of the cells to develop into the osteo-, chondro- and adipogenic lineage. Moreover we were able to detect 184 adipogenic candidate genes (85 with increased, 99 with decreased expression) that were differentially expressed during adipogenic development of MSC and/or between MSC and fat tissue in a highly significant way (p < 0.00001). Subsequently, groups of up- or down-regulated genes were formed and analyzed with biochemical and cluster tools. Among the 184 genes, we identified already known transcription factors such as PPARG, C/EBPA and RTXA. Several of the genes could be linked to corresponding biochemical pathways like the adipocyte differentiation, adipocytokine signalling, and lipogenesis pathways. We also identified new candidate genes possibly related to adipogenesis, such as SCARA5, coding for a receptor with a putative transmembrane domain and a collagen-like domain, and MRAP, encoding an endoplasmatic reticulum protein.

CONCLUSIONS

Comparing differential gene expression profiles of human MSC and native fat cells or tissue allowed us to establish a comprehensive differential kinetic gene expression network of adipogenesis. Based on this, we identified known and unknown genes and biochemical pathways that may be relevant for adipogenic differentiation. Our results encourage further and more focused studies on the functional relevance of particular adipogenic candidate genes.

Evidence of an intracellular angiotensin-generating system and non-AT1, non-AT2 binding site in a human pancreatic cell line

OBJECTIVES

To assess the presence of a local angiotensin-generating systems (LAGS) and its participation in tumor growth in the human pancreatic cancer derived cell line Capan-1.

METHODS

Capan-1 cells were cultured in Dulbecco modified Eagle medium, and angiotensin I was assayed by radioimmunoassay and angiotensin II and vascular endothelial growth factor were assayed by enzyme-linked immunosorbent assay in the supernatant. Immunohistochemistry and reverse transcription-polymerase chain reaction were performed for the expression of AT1 and AT2 receptors. Angiotensin II binding assays and blockade were studied.

RESULTS

High levels of both angiotensins I and II were found in Capan-1 cells, although neither angiotensin I nor angiotensin II was detected in the cell culture supernatant. Reverse transcription-polymerase chain reaction and immunocytochemistry revealed that Capan-1 cells do not express AT1 and AT2 receptors; however, specific binding to the cell membrane was identified for angiotensin II. Neither exogenous angiotensin II nor Dup753 (specific AT1 receptor blocker) affected Capan-1 cells' proliferation or vascular endothelial growth factor secretion.

CONCLUSIONS

Detection of both angiotensin I and angiotensin II along with specific binding of angiotensin II in Capan-1 cells provides evidence of the existence of a LAGS that operates in an intracrine manner. Intracellular angiotensin II may play a role in the aggressiveness of pancreatic cancer and is a possible target for therapeutic agents.