Role of host angiotensin II type 1 receptor in tumor angiogenesis and growth

Diverse biological functions of the renin-angiotensin system

The renin-angiotensin system (RAS) has been widely known as a circulating endocrine system involved in the control of blood pressure. However, components of RAS have been found to be localized in rather unexpected sites in the body including the kidneys, brain, bone marrow, immune cells, and reproductive system. These discoveries have led to steady, growing evidence of the existence of independent tissue RAS specific to several parts of the body. It is important to understand how RAS regulates these systems for a variety of reasons: It gives a better overall picture of human physiology, helps to understand and mitigate the unintended consequences of RAS-inhibiting or activating drugs, and sets the stage for potential new therapies for a variety of ailments. This review fulfills the need for an updated overview of knowledge about local tissue RAS in several bodily systems, including their components, functions, and medical implications.

Hypertension and hyperglycaemia are positively correlated with local invasion of early cervical cancer

Background

Metabolic disorders are involved in the development of numerous cancers, but their association with the progression of cervical cancer is unclear. This study aims to investigate the association between metabolic disorders and the pathological risk factors and survival in patients with early cervical cancer.

Methods

Patients with FIGO IB1 (2009) primary cervical cancer who underwent radical hysterectomy and systematic pelvic lymph node dissection at our institution from October 2014 to December 2017 were included retrospectively. Clinical data regarding the metabolic syndrome and surgical pathology of the patient were collected. The correlations between metabolic disorders (hypertension, hyperglycemia, and obesity) and clinicopathological characteristics as well as survival after surgery were analyzed.

Results

The study included 246 patients with clinical IB1 cervical cancer, 111 (45.1%) of whom had at least one of the comorbidities of hypertension, obesity, or hyperglycemia. Hypertension was positively correlated with parametrial invasion and poorly differentiated histology; hyperglycemia was positively correlated with stromal invasion; obesity was negatively associated with lymph node metastasis; but arbitrary disorder did not show any correlation with pathologic features. Hypertension was an independent risk factor for parametrial invasion (OR=6.54, 95% CI: 1.60-26.69); hyperglycemia was an independent risk factor for stromal invasion (OR=2.05, 95% CI: 1.07-3.95); and obesity was an independent protective factor for lymph node metastasis (OR=0.07, 95% CI: 0.01-0.60). Moreover, the patients with hypertension had a significantly lower 5-year OS rate (70.0% vs. 95.3%, P<0.0001) and a significantly lower 5-year PFS rate than those without hypertension (70.0% vs. 91.2%, P=0.010).

Conclusion

Hypertension and hyperglycemia are positively associated with local invasion of early cervical cancer, which need to be verified in multi-center, large scale studies.

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.

Prognosis of Midkine and AT1R expression in resectable head and neck squamous cell carcinoma

BACKGROUND

Research studies have demonstrated that Midkine (MDK) can influence the expression and activity of Renin-angiotensin system (RAS) components. Angiotensin II is involved in tumor growth and angiogenesis in different cancers. We previously observed Angiotensin II receptor blockers (ARBs) improve the survival rates of patients with oral cancers. These findings have prompted us to investigate whether MDK can influence the RAS pathway, mainly through its association with angiotensin II type 1 receptor (AT1R), which contributes to the observed poor prognosis in head and neck squamous cell carcinoma (HNSCC) patients.

METHODS

MDK and AT1R expressions were examined in 150 HNSCC patients post-operation by immunohistochemical staining between 1 January 2010 and 31 December 2016. We tested the over-expression and silencing of MDK to evaluate the AT1R expression and functional biological assays in HNSCC cell lines HSC-3 and SAS.

RESULTS

Positive expression of MDK is correlated with positive AT1R expression. MDK predicted poor NSCC patients' survival. Silencing MDK could suppress AT1R and pAKT expression and reduce the growth, migration, and invasion of HNSCC cells. ARB also inhibits MDK stimulating HNSCC cell proliferation. Overexpression of MDK could upregulate AT1R and pAKT.

CONCLUSIONS

MDK is an independent prognostic factor of HNSCC post-operation, and AT1R regulates HNSCC cell growth, invasion, and migration. Positive MDK and AT1R expressions are highly correlated. Mechanistically, the interaction between MDK and AT1R is crucial for MDK-mediated cell viability, and inhibiting AT1R can effectively counteract or abolish these effects. Furthermore, MDK exerts a regulatory role in the expression of AT1R, as well as in the growth and motility of HNSCC cells. These findings highlight the involvement of the interaction between MDK, AT1R, and the pAkt signaling pathways in HNSCC cell viability growth.

Metabolic syndrome and thyroid Cancer: risk, prognosis, and mechanism

The increasing incidence of thyroid cancer (TC) cannot be fully explained by overdiagnosis. Metabolic syndrome (Met S) is highly prevalent due to the modern lifestyle, which can lead to the development of tumors. This review expounds on the relationship between Met S and TC risk, prognosis and its possible biological mechanism. Met S and its components were associated with an increased risk and aggressiveness of TC, and there were gender differences in most studies. Abnormal metabolism places the body in a state of chronic inflammation for a long time, and thyroid-stimulating hormones may initiate tumorigenesis. Insulin resistance has a central role assisted by adipokines, angiotensin II, and estrogen. Together, these factors contribute to the progression of TC. Therefore, direct predictors of metabolic disorders (e.g., central obesity, insulin resistance and apolipoprotein levels) are expected to become new markers for diagnosis and prognosis. cAMP, insulin-like growth factor axis, angiotensin II, and AMPK-related signaling pathways could provide new targets for TC treatment.

Associations between genetically predicted levels of blood metabolites and pancreatic cancer risk

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive solid malignancies, which is featured by systematic metabolism. Thus, a better understanding of metabolic dysregulation in PDAC is important to better characterize its etiology. Here, we performed a large metabolome-wide association study (MWAS) to systematically explore associations between genetically predicted metabolite levels in blood and PDAC risk. Using data from 881 subjects of European descent in the TwinsUK Project, comprehensive genetic models were built to predict serum metabolite levels. These prediction models were applied to the genetic data of 8275 cases and 6723 controls included in the PanScan (I, II and III) and PanC4 consortia. After assessing the metabolite-PDAC risk associations by a slightly modified TWAS/FUSION framework, we identified five metabolites (including two dipeptides) showing significant associations with PDAC risk at false discovery rate (FDR) <0.05. Integrated with gut microbial information, two-sample Mendelian randomization (MR) analyses were further performed to investigate the relationship among serum metabolites, gut microbiome features and PDAC. The flavonoid-degrading bacteria Flavonifractor sp90199495 was found to be associated with metabolite X-21849 and it was also shown to be associated with PDAC risk. Collectively, our study identified novel candidate metabolites for PDAC risk, which could lead to new insights into the etiology of PDAC and improved treatment options.

Molecular differences of angiogenic versus vessel co-opting colorectal cancer liver metastases at single-cell resolution

BACKGROUND

Colorectal cancer liver metastases (CRCLM) are associated with a poor prognosis, reflected by a five-year survival rate of 14%. Anti-angiogenic therapy through anti-VEGF antibody administration is one of the limited therapies available. However, only a subgroup of metastases uses sprouting angiogenesis to secure their nutrients and oxygen supply, while others rely on vessel co-option (VCO). The distinct mode of vascularization is reflected by specific histopathological growth patterns (HGPs), which have proven prognostic and predictive significance. Nevertheless, their molecular mechanisms are poorly understood.

METHODS

We evaluated CRCLM from 225 patients regarding their HGP and clinical data. Moreover, we performed spatial (21,804 spots) and single-cell (22,419 cells) RNA sequencing analyses to explore molecular differences in detail, further validated in vitro through immunohistochemical analysis and patient-derived organoid cultures.

RESULTS

We detected specific metabolic alterations and a signature of WNT signalling activation in metastatic cancer cells related to the VCO phenotype. Importantly, in the corresponding healthy liver of CRCLM displaying sprouting angiogenesis, we identified a predominantly expressed capillary subtype of endothelial cells, which could be further explored as a possible predictor for HGP relying on sprouting angiogenesis.

CONCLUSION

These findings may prove to be novel therapeutic targets to the treatment of CRCLM, in special the ones relying on VCO.

Drug Repurposing in Non-Small Cell Lung Carcinoma: Old Solutions for New Problems

Lung cancer is the second most common cancer and the leading cause of cancer-related deaths in 2022. The majority (80%) of lung cancer cases belong to the non-small cell lung carcinoma (NSCLC) subtype. Despite the increased screening efforts, the median five-year survival of metastatic NSCLC remains low at approximately 3%. Common treatment approaches for NSCLC include surgery, multimodal chemotherapy, and concurrent radio and chemotherapy. NSCLC exhibits high rates of resistance to treatment, driven by its heterogeneity and the plasticity of cancer stem cells (CSCs). Drug repurposing offers a faster and cheaper way to develop new antineoplastic purposes for existing drugs, to help overcome therapy resistance. The decrease in time and funds needed stems from the availability of the pharmacokinetic and pharmacodynamic profiles of the Food and Drug Administration (FDA)-approved drugs to be repurposed. This review provides a synopsis of the drug-repurposing approaches and mechanisms of action of potential candidate drugs used in treating NSCLC, including but not limited to antihypertensives, anti-hyperlipidemics, anti-inflammatory drugs, anti-diabetics, and anti-microbials.

Effect of renin-angiotensin-aldosterone system inhibitors on survival outcomes in cancer patients treated with immune checkpoint inhibitors: a systematic review and meta-analysis

Background

Effect of renin-angiotensin-aldosterone system inhibitors (RAASIs) in combination with immune checkpoint inhibitors (ICIs) on prognoses in cancer patients remains controversial. This study systematically evaluated the effect of RAASIs on survival outcomes in cancer patients receiving ICIs treatment and provided an evidence-based reference for the rational use of RAASIs and ICIs combination therapy in clinical practice.

Methods

Studies evaluating the prognosis of RAASIs-used versus RAASIs-free in cancer patients receiving ICIs treatment from inception to 1 November 2022 were retrieved by searching PubMed, Cochrane Library, Web of Science, Embase, and major conference proceedings. Studies in English reporting hazard ratios (HRs) with 95% confidence intervals (CIs) for overall survival (OS) and/or progression-free survival (PFS) were included. Statistical analyses were conducted using the software Stata 17.0.

Results

A total of 12 studies containing 11739 patients were included, comprising ~4861 patients in the RAASIs-used and ICIs-treated group and ~6878 patients in RAASIs-free and ICIs-treated group. The pooled HR was 0.85 (95%CI, 0.75-0.96; P = 0.009) for OS and 0.91 (95%CI, 0.76-1.09; P = 0.296) for PFS, indicating a positive effect of RAASIs concomitant with ICIs on cancer patients. This effect was observed especially in patients with urothelial carcinoma (HR, 0.53; 95%CI, 0.31-0.89; P = 0.018) and renal cell carcinoma (HR, 0.56; 95%CI, 0.37-0.84; P = 0.005) on OS.

Conclusion

Concomitant use of RAASIs and ICIs enhanced the efficacy of ICIs and this combination regimen was associated with significantly improved OS and a trend towards better PFS. RAASIs can be considered as adjuvant drugs when hypertensive patients receive ICIs treatment. Our results provide an evidence-based reference for the rational use of the RAASIs and ICIs combination therapy to improve the efficacy of ICIs in clinical practice.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42022372636; https://inplasy.com/, identifier INPLASY2022110136.

Potential use of angiotensin receptor blockers in skin pathologies

Renin-angiotensin system (RAS) components such as angiotensin II, angiotensin receptors (AT₁R and AT₂R), and angiotensin-converting enzyme (ACE) are expressed in different cell types of the skin. Through AT1R, angiotensin II increases proinflammatory cytokines contributing to fibrosis, angiogenesis, proliferation, and migration of immune cells to the skin. In contrast, AT₂R suppresses the effects mentioned above. Many studies show that angiotensin receptor blockers (ARBs) and angiotensin-converting enzymes (ACEi) reduce the proinflammatory cytokines and fibrogenic factors including transforming growth factor β (TGF-β), Connective tissue growth factor (CTGF), and IL-6. This review article provides a detailed research study on the implications of ARBs in wound healing, hypertrophic scar, and keloids. We further discuss the therapeutic potentials of ARBs in autoimmune and autoinflammatory skin diseases and cancer, given their anti-fibrotic and anti-inflammatory effects.

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.

System analysis based on the cuproptosis-related genes identifies LIPT1 as a novel therapy target for liver hepatocellular carcinoma

BACKGROUND

Liver hepatocellular carcinoma (LIHC) ranks sixth among the most common types of cancer with a high mortality rate. Cuproptosis is a newly discovered type of cell death in tumor, which is characterized by accumulation of intracellular copper leading to the aggregation of mitochondrial lipoproteins and destabilization of proteins. Thus, understanding the exact effects of cuproptosis-related genes in LIHC and determining their prognosticvalue is critical. However, the prognostic model of LIHC based on cuproptosis-related genes has not been reported.

METHODS

Firstly, we downloaded transcriptome data and clinical information of LIHC patients from TCGA and GEO (GSE76427), respectively. We then extracted the expression of cuproptosis-related genes and established a prognostic model by lasso cox regression analysis. Afterwards, the prediction performance of the model was evaluated by Kaplan-Meier survival analysis and receiver operating characteristic curve (ROC). Then, the prognostic model and the expression levels of the three genes were validated using the dataset from GEO. Subsequently, we divided LIHC patients into two subtypes by non-negative matrix factorization (NMF) classification and performed survival analysis. We constructed a Sankey plot linking different subtypes and prognostic models. Next, we calculate the drug sensitivity of each sample from patients in the high-risk group and low-risk group by the R package pRRophetic. Finally, we verified the function of LIPT1 in LIHC.

RESULTS

Using lasso cox regression analysis, we developed a prognostic risk model based on three cuproptosis-related genes (GCSH, LIPT1 and CDKN2A). Both in the training and in the test sets, the overall survival (OS) of LIHC patients in the low-risk group was significantly longer than that in the high-risk group. By performing NMF cluster, we identified two molecular subtypes of LIHC (C1 and C2), with C1 subtype having significantly longer OS and PFS than C2 subtype. The ROC analysis indicated that our model had a precisely predictive capacity for patients with LIHC. The multivariate Cox regression analysis indicated that the risk score is an independent predictor. Subsequently, we identified 71 compounds with IC50 values that differed between the high-risk and low-risk groups. Finally, we determined that knockdown of LIPT1 gene expression inhibited proliferation and invasion of hepatoma cells.

CONCLUSION

In this study, we developed a novel prognostic model for hepatocellular carcinoma based on cuproptosis-related genes that can effectively predict the prognosis of LIHC patients. The model may be helpful for clinicians to make clinical decisions for patients with LIHC and provide valuable insights for individualized treatment. Two distinct subtypes of LIHC were identified based on cuproptosis-related genes, with different prognosis and immune characteristics. In addition, we verified that LIPT1 may promote proliferation, invasion and migration of LIHC cells. LIPT1 might be a new potential target for therapy of LIHC.

Hypertension Was Associated with Higher Tumor Stages in Papillary Thyroid Cancer: A Large Sample Single-Center Study

Background: Hypertension (HTN) is known to increase the risk of thyroid cancer. However, few studies have explored the association between HTN and the prognostic factors of papillary thyroid cancer (PTC). Methods: We retrospectively evaluated 2838 PTC patients treated with surgery at our center between January 2017 and September 2020. The association between both HTN and antihypertensive drug use and the clinicopathological features of the PTC patients was analyzed. The odds ratios (ORs) were estimated using both univariate and multivariate logistic regression models, which were adjusted for the patients' age, sex, and thyroid-stimulating hormone level. Results: A total of 2838 patients were enrolled in this study, including 409 patients with HTN. In the multivariate analysis, HTN was associated with larger tumor size [OR = 1.51, 95% confidence interval (CI): 1.10-2.07], lymph node metastasis (OR = 1.43, 95% CI: 1.02-1.99), and higher tumor stages (OR = 1.79, 95% CI: 1.12-2.86). There was no statistical difference between females >40 years of age and any pathological features, while a positive association was observed between older males and larger tumors (OR = 1.87, 95% CI: 1.01-3.45), and lymph node metastasis (OR = 2.01, 95% CI: 1.08-3.73). No statistical difference was found in the effects of taking alone calcium channel blockers, angiotensin-converting enzyme inhibitors/angiotensin II-receptor blockers, and their combination on the pathological features of PTC. Conclusion: PTC patients with HTN, particularly males of age >40, tend to have invasive features. Common antihypertension therapy appears to exert no effect on the pathological characteristics of these patients.

Antihypertensive Drugs and Cancer Risk

Hypertension is the most prevalent comorbidity in cancer patients. Consequently, many cancer patients are prescribed antihypertensive drugs before cancer diagnosis or during cancer treatment. However, whether antihypertensive drugs affect the incidence, treatment efficacy, or prognosis of cancer remains unanswered. For instance, renin-angiotensin and β-adrenergic signaling may be involved not only in blood pressure elevation but also in cell proliferation, angiogenesis, and tissue invasion. Therefore, the inhibition of these pathways may have beneficial effects on cancer prevention or treatment. In this article, we reviewed several studies regarding antihypertensive drugs and cancer. In particular, we focused on the results of clinical trials to evaluate whether the use of antihypertensive drugs affects future cancer risk and prognosis. Unfortunately, the results are somewhat inconsistent, and evidence demonstrating the effect of antihypertensive drugs remains limited. We indicate that the heterogeneity in the study designs makes it difficult to clarify the causal relationship between antihypertensive drugs and cancer. We also propose that additional experimental studies, including research with induced pluripotent cells derived from cancer patients, single-cell analyses of cancer cell clusters, and clinical studies using artificial intelligence electronic health record systems, might be helpful to reveal the precise association between antihypertensive drugs and cancer risk.

The use of renin angiotensin aldosterone system inhibitors may be associated with decreased mortality after cancer surgery

Renin–angiotensin–aldosterone system (RAAS) inhibitors are antihypertensive agents with conflicting results on protective effects against some types of cancer. In light of these controversies, we aimed to study the effects of RAAS inhibitors in patients undergoing cancer surgery. From March 2010 to December 2019, consecutive adult patients with antihypertensive drug prescription at discharge after cancer surgery were enrolled and divided into two groups according to RAAS inhibitors prescription. The primary outcome was 5-year mortality after surgery. Secondary outcomes included mortalities during 3-year and 1-year follow-ups and cancer-specific mortality and recurrence rates during 5-, 3-, and 1-year follow-ups. A total of 19,765 patients were divided into two groups according to RAAS inhibitor prescription at discharge: 8,374 (42.4%) patients in the no RAAS inhibitor group and 11,391 (57.6%) patients in the RAAS inhibitor group. In 5022 pairs of propensity-score matched population, 5-year mortality was significantly lower in the RAAS inhibitor group (11.4% vs. 7.4%, hazard ratio [HR] 0.73, 95% confidence interval [CI] 0.64–0.83, P < 0.001), and 5-year recurrence rate was also lower for the RAAS inhibitor group (5.3% vs. 3.7%, HR 0.82, 95% CI 0.68–0.99, P = 0.04). In our analysis, RAAS inhibitor was associated with decreased 5-year mortality in hypertensive patients who underwent cancer surgery. Prescription of RAAS inhibitor in accordance with current guidelines may be associated with improved mortality after cancer surgery.

Prognostic impact of angiotensin-converting enzyme inhibitors and angiotensin receptors blockers in esophageal or gastric cancer patients with hypertension - a real-world study

Background

Angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) are used in treating cardiovascular diseases. Previous studies indicated that ACEIs/ARBs may benefit cancer patients by inhibiting tumor angiogenesis and proliferation. The effect of ACEIs/ARBs on cancer survival in esophageal and gastric cancer is still unclear. This study is to investigate the association between ACEIs/ARBs usage and esophageal and gastric cancer prognosis.

Methods

This retrospective cohort study identified esophageal and gastric cancer patients during 2008–2016 from the Taiwan Cancer Registry, and obtained medication usage and follow-up information from the National Health Insurance Research Database and Death Registry. Analysis groups were defined as ACEIs/ARBs user or non-user based on the usage of ACEIs/ARBs within the 6 months after cancer diagnosis. The stabilized inverse probability of treatment weighting using propensity scores was applied to balance covariates between study groups. We also used Kaplan-Meier estimates and Cox regression to compare survival outcome and estimate hazard ratios (HRs).

Results

We identified 14,463 and 21,483 newly-diagnosed esophageal and gastric cancer patients during 2008–2016. ACEIs/ARBs users were associated with lower risk of cancer-specific mortality, although only significantly in gastric cancer (gastric: adjusted HR = 0.87, 95% CI = 0.78–0.97; esophageal: adjusted HR =0.88, 95% CI = 0.76–1.02). A better survival outcome was observed among patients who received higher cumulative defined daily dose of ACEIs/ARBs.

Conclusions

We found that using ACEIs/ARBs after cancer diagnosis were associated with lower risk of mortality. Our results add to the knowledge of the benefit of ACEIs/ARBs against mortality in individuals with esophageal/gastric cancer patients with hypertension.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09513-4.

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.

Blood pressure and risk of cancer: a Mendelian randomization study

Background

Previous large observational cohort studies showed higher blood pressure (BP) positively associated with cancer. We used Mendelian randomization (MR) to obtain less confounded estimates of BP on total and site-specific cancers.

Methods

We applied replicated genetic instruments for systolic and diastolic BP to summary genetic associations with total cancer (37387 cases, 367856 non-cases) from the UK Biobank, and 17 site-specific cancers (663–17881 cases) from a meta-analysis of the UK Biobank and the Kaiser Permanente Genetic Epidemiology Research on Adult Health and Aging. We used inverse-variance weighting with multiplicative random effects as the main analysis, and sensitivity analyses including the weighted median, MR-Egger and multivariable MR adjusted for body mass index and for smoking. For validation, we included breast (Breast Cancer Association Consortium: 133384 cases, 113789 non-cases), prostate (Prostate Cancer Association Group to Investigate Cancer Associated Alterations in the Genome Consortium: 79194 cases, 61112 non-cases) and lung (International Lung and Cancer Consortium: 10246 cases, 38295 non-cases) cancer from large consortia. We used asthma as a negative control outcome.

Results

Systolic and diastolic BP were unrelated to total cancer (OR 0.98 per standard deviation higher [95% confidence interval (CI) 0.89, 1.07] and OR 1.00 [95% CI 0.92, 1.08]) and to site-specific cancers after accounting for multiple testing, with consistent findings from consortia. BP was nominally associated with melanoma and possibly kidney cancer, and as expected, not associated with asthma. Sensitivity analyses using other MR methods gave similar results.

Conclusions

In contrast to previous observational evidence, BP does not appear to be a risk factor for cancer, although an effect on melanoma and kidney cancer cannot be excluded. Other targets for cancer prevention might be more relevant.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-09067-x.

Repurposing of Anticancer Stem Cell Drugs in Brain Tumors

Brain tumors in adults may be infrequent when compared with other cancer etiologies, but they remain one of the deadliest with bleak survival rates. Current treatment modalities encompass surgical resection, chemotherapy, and radiotherapy. However, increasing resistance rates are being witnessed, and this has been attributed, in part, to cancer stem cells (CSCs). CSCs are a subpopulation of cancer cells that reside within the tumor bulk and have the capacity for self-renewal and can differentiate and proliferate into multiple cell lineages. Studying those CSCs enables an increasing understanding of carcinogenesis, and targeting CSCs may overcome existing treatment resistance. One approach to weaponize new drugs is to target these CSCs through drug repurposing which entails using drugs, which are Food and Drug Administration-approved and safe for one defined disease, for a new indication. This approach serves to save both time and money that would otherwise be spent in designing a totally new therapy. In this review, we will illustrate drug repurposing strategies that have been used in brain tumors and then further elaborate on how these approaches, specifically those that target the resident CSCs, can help take the field of drug repurposing to a new level.

The Role of the Renin-Angiotensin System in the Cancer Stem Cell Niche

Cancer stem cells (CSCs) drive metastasis, treatment resistance, and tumor recurrence. CSCs reside within a niche, an anatomically distinct site within the tumor microenvironment (TME) that consists of malignant and non-malignant cells, including immune cells. The renin-angiotensin system (RAS), a critical regulator of stem cells and key developmental processes, plays a vital role in the TME. Non-malignant cells within the CSC niche and stem cell signaling pathways such as the Wnt, Hedgehog, and Notch pathways influence CSCs. Components of the RAS and cathepsins B and D that constitute bypass loops of the RAS are expressed on CSCs in many cancer types. There is extensive in vitro and in vivo evidence showing that RAS inhibition reduces tumor growth, cell proliferation, invasion, and metastasis. However, there is inconsistent epidemiological data on the effect of RAS inhibitors on cancer incidence and survival outcomes, attributed to different patient characteristics and methodologies used between studies. Further mechanistic studies are warranted to investigate the precise effects of the RAS on CSCs directly and/or the CSC niche. Targeting the RAS, its bypass loops, and convergent signaling pathways participating in the TME and other key stem cell pathways that regulate CSCs may be a novel approach to cancer treatment.

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.

New-Onset Cancer in the HF Population: Epidemiology, Pathophysiology, and Clinical Management

PURPOSE OF REVIEW

Oncological treatments are known to induce cardiac toxicity, but the impact of new-onset cancer in patients with pre-existing HF remains unknown. This review focuses on the epidemiology, pathophysiological mechanisms, and clinical implications of HF patients who develop malignancies.

RECENT FINDINGS

Novel findings suggest that HF and cancer, beside common risk factors, are deeply linked by shared pathophysiological mechanisms. In particular, HF itself may enhance carcinogenesis by producing pro-inflammatory cytokines, and it has been suggested that neurohormonal activation, commonly associated with the failing heart, might play a pivotal role in promoting neoplastic transformation. The risk of malignancies seems to be higher in HF patients compared to the general population, probably due to shared risk factors and common pathophysiological pathways. Additionally, management of these patients represents a challenge for clinicians, considering that the co-existence of these diseases significantly worsens patients' prognosis and negatively affects therapeutic options for both diseases.

Role of Melatonin in Angiotensin and Aging

The cellular utilization of oxygen leads to the generation of free radicals in organisms. The accumulation of these free radicals contributes significantly to aging and several age-related diseases. Angiotensin II can contribute to DNA damage through oxidative stress by activating the NAD(P)H oxidase pathway, which in turn results in the production of reactive oxygen species. This radical oxygen-containing molecule has been linked to aging and several age-related disorders, including renal damage. Considering the role of angiotensin in aging, melatonin might relieve angiotensin-II-induced stress by enhancing the mitochondrial calcium uptake 1 pathway, which is crucial in preventing the mitochondrial calcium overload that may trigger increased production of reactive oxygen species and oxidative stress. This review highlights the role and importance of melatonin together with angiotensin in aging and age-related diseases.

ACE Inhibitor Therapy Does Not Influence the Survival Outcomes of Patients with Colorectal Liver Metastases Following Liver Resection

BACKGROUND

Angiotensin-converting enzyme (ACE) inhibitors have been shown to possibly influence the survival outcomes in certain cancers. The aim of this study was to evaluate the impact of ACE inhibitors on the outcomes of patients undergoing liver resection for colorectal liver metastases (CRLM). The secondary aim was to determine whether ACE inhibitors influenced histopathological changes in CRLM.

METHODS

Patients treated with liver resection for CRLM over a 13-year period were identified from a prospectively maintained database. Data including demographics, primary tumour treatment, surgical data, histopathology analysis and clinical outcome were collated and analysed.

RESULTS

A total of 586 patients underwent primary hepatic resections for CRLM during this period including 100 patients on ACE inhibitors. The median follow-up period was 23 (range: 12-96) months, in which 267 patients developed recurrent disease and 131 patients died. Independent predictors of disease-free survival on multivariate analysis included synchronous presentation, neoadjuvant chemotherapy, major liver resection, tumour size and number, extent of hepatic steatosis, R0 resection and presence of perineural invasion. Poorer overall survival was associated with neoadjuvant treatment, major liver resection, presence of multiple metastases, perineural invasion and positive resection margins on multivariate analysis. ACE inhibitors did not influence the survival outcome or histological presentation in CRLM.

CONCLUSION

The use of ACE inhibitors did not affect the survival outcome or tumour biology in patients with CRLM following liver resection.

Effects of hypertension on cancer survival: A meta-analysis

BACKGROUND

Hypertension is usually associated with increased cardiovascular mortality. Uncertainty exists about the possible role of hypertension as a poor prognostic factor for cancer-specific mortality (CSM). To assess the association between pre-existing hypertension and the risk of mortality and relapse after a diagnosis of cancer, we performed a systematic review and meta-analysis of published studies.

METHODS

PubMed, Scopus, Web of Science, the Cochrane Library and EMBASE were searched from inception until May 2020, without language restrictions, for observational studies reporting the prognosis of patients with hypertension and cancer. The primary outcome of the study refers to CSM in hypertensive vs nonhypertensive patients, and secondary endpoints were overall mortality (OM) and progression- or relapse-free survival. The effect size was reported as hazard ratios (HRs) with 95% CIs.

RESULTS

Mortality and relapse associated with hypertension in patients with various cancers were evaluated among 1 603 437 participants (n = 66 studies). Overall, diagnosis of cancer and hypertension was associated with an increased independent risk of OM (HR = 1.2 [95% CI, 1.13-1.27], P < .01) and CSM (HR = 1.12 [95% CI, 1.04-1.21], P < .01) but not of relapse (HR = 1.08 [95% CI, 0.98-1.19], P = .14).

CONCLUSIONS

Among cancer patients, those with pre-existing hypertension have a poorer outcome, probably due to multifactorial reasons. Adequate control of lifestyle, more intensive follow-ups, monitoring for hypertension- and anticancer-related cardiovascular complications, and establishing multidisciplinary cardio-oncology units can be useful measures for reducing mortality and improving care in this setting.

Breast cancer and the renin-angiotensin system (RAS): Therapeutic approaches and related metabolic diseases

The Renin-Angiotensin System (RAS) is classically recognized for regulating blood pressure and fluid balance. Recently, this role has extended to other areas including inflammation, obesity, diabetes, as well as breast cancer. RAS components are expressed in normal and cancerous breast tissues, and downregulation of RAS inhibits metastasis, proliferation, angiogenesis, and desmoplasia in the tumor microenvironment. Therefore, RAS inhibitors (Angiotensin receptor blockers, ARBs, or angiotensin converting enzyme inhibitors, ACE-I) may be beneficial as preventive adjuvant therapies to thwart breast cancer development and improve outcomes, respectively. Given the beneficial effects of RAS inhibitors in metabolic diseases, which often co-exist in breast cancer patients, combining RAS inhibitors with other breast cancer therapies may enhance the effectiveness of current treatments. This review scrutinizes above associations, to advance our understanding of the role of RAS in breast cancer and its potential for repurposing of RAS inhibitors to improve the therapeutic approach for breast cancer patients.

Extracellular matrix and its therapeutic potential for cancer treatment

The extracellular matrix (ECM) is one of the major components of tumors that plays multiple crucial roles, including mechanical support, modulation of the microenvironment, and a source of signaling molecules. The quantity and cross-linking status of ECM components are major factors determining tissue stiffness. During tumorigenesis, the interplay between cancer cells and the tumor microenvironment (TME) often results in the stiffness of the ECM, leading to aberrant mechanotransduction and further malignant transformation. Therefore, a comprehensive understanding of ECM dysregulation in the TME would contribute to the discovery of promising therapeutic targets for cancer treatment. Herein, we summarized the knowledge concerning the following: (1) major ECM constituents and their functions in both normal and malignant conditions; (2) the interplay between cancer cells and the ECM in the TME; (3) key receptors for mechanotransduction and their alteration during carcinogenesis; and (4) the current therapeutic strategies targeting aberrant ECM for cancer treatment.

Dysfunction of retinal neurons and glia during diabetes

Diabetic retinopathy is the leading cause of blindness in those of working age. It is well known that the retinal vasculature is altered during diabetes. More recently, it has emerged that neuronal and glial dysfunction occurs in those with diabetes. Current research is directed at understanding these neuronal and glial changes because they may be an early manifestation of disease processes that ultimately lead to vascular abnormality. This review will highlight the recent advances in our understanding of the neuronal and glial changes that occur during diabetes.

CCL5 production by fibroblasts through a local renin-angiotensin system in malignant melanoma affects tumor immune responses

PURPOSE

To enhance the antitumor effects of anti-programmed death-1 (PD-1) antibodies, it is important to reverse cancer-induced immunosuppression. We previously reported that a localized renin-angiotensin system in the tumor microenvironment inhibited tumor immunity via macrophages. In this study, we analyzed the underlying mechanism through which fibroblasts express tumor immunity influenced by the angiotensin receptor.

METHODS

We used an angiotensin receptor inhibitor (ARB) to inhibit renin-angiotensin system. Furthermore, angiotensin receptors were knocked out from mice fibroblasts, which were then collected. The fibroblasts and a malignant melanoma were then transfused into a mouse model and tumor immunity response was analyzed.

RESULTS

Fibroblasts produced CC motif chemokine ligand 5 (CCL5) on renin-angiotensin system stimulation, and this production decreased after ARB administration. In mice with transplanted malignant melanoma, ARB administration resulted in decreased CCL5 concentration in the blood, increase in tumor-infiltrating T cells, decrease in regulatory T cells, as well as an increase in tumor antigen-specific T-cell responses. The mice in which the angiotensin receptor knockout fibroblasts and malignant melanoma were transplanted showed a similar decrease in CCL5 concentration and increased tumor antigen-specific T-cell responses. Furthermore, ARB and anti-PD-1 antibody were administered in combination, which resulted in significantly better tumor growth inhibition over monotherapy.

CONCLUSION

Inhibiting renin-angiotensin system restored the therapeutic efficacy of inhibited anti-PD-1 antibodies. Thus, this could be considered a valid approach to enhance the therapeutic efficacy of anti-PD-1 antibodies.

A 2-Benzylmalonate Derivative as STAT3 Inhibitor Suppresses Tumor Growth in Hepatocellular Carcinoma by Upregulating β-TrCP E3 Ubiquitin Ligase

The aberrant activation of a signal transducer and activator of transcription 3 (STAT3) restrains type I interferon (IFN) α/β-induced antiviral responses and is associated with the development of cancer. Designing specific STAT3 inhibitors will thus provide new options for use as IFN therapy. Herein, we identified a novel small molecule, dimethyl 2-(4-(2-(methyl(phenyl(p-tolyl)methyl)amino)ethoxy)benzyl)malonate (CIB-6), which can inhibit the IFN-α-induced interferon stimulated response element (ISRE) luciferase reporter (IC₅₀ value = 6.4 μM) and potentiate the antiproliferative effect of IFN-α in human hepatocellular carcinoma (HCC) cells. CIB-6 was found to bind to the STAT3 Src homology 2 (SH2) domain, thereby selectively inhibiting STAT3 phosphorylation without affecting Janus kinases and STAT1/2. CIB-6 also inhibited the migration and invasion of HCC cells by inhibiting the epithelial-mesenchymal transition (EMT) process. Mechanistically, CIB-6 reduced the expression of β-catenin (an EMT key protein) via upregulating β-transducin repeat-containing protein (β-TrCP) and curbed nuclear factor kappa-B (NF-κB) activation through restricting the phosphorylation of the inhibitor of NF-κB (IκB) kinase (IKK) via STAT3 inhibition. Treatment with CIB-6 significantly retarded tumor growth in nude mice with SK-HEP-1 xenografts. In addition, clinical sample analysis revealed that lower β-TrCP and higher β-catenin expression could affect the median survival time of HCC patients. Our findings suggest that CIB-6 could be a new therapeutic strategy for HCC therapy through STAT3-mediated β-TrCP/β-catenin/NF-κB axis.

Sex differences exist in brain renin-angiotensin system-regulating aminopeptidase activities in transplacental ethyl-nitrosourea-induced gliomas

INTRODUCTION

The renin angiotensin system (RAS) is emerging as an important target for the treatment of glioma. We had described that the local RAS is involved in vivo in tumor growth in the rat model of experimental C6 glioma implanted at the subcutaneous region, through the modification of several proteolytic regulatory enzymes of aminopeptidase type.

METHODS

We analyze RAS-regulating aminopeptidase activities in plasma and brain tissue of control male and female rats and rats with transplacental ethylnitrosourea-induced gliomas.

RESULTS

No differences were found either the mean total number of tumors per animal or the tumor volume between male and female animals. However, we have found increased levels in aspartyl aminopeptidase in both males and females and of aminopeptidase B only in males. On the contrary, decreased levels were found in aminopeptidase N and insulin-regulated aminopeptidase activities in both males and females, whereas aminopeptidase A only decreased in females. Decreased levels of aminopeptidase N, aminopeptidase B and insulin-regulated aminopeptidase were also shown in plasma of only female rats.

CONCLUSIONS

Under the complexity of RAS cascade, the changes found suggest the predominant actions of angiotensin III against a decreased action of angiotensin II and angiotensin IV. We conclude that angiotensin peptides are involved in tumor growth in this rat model of glioma and that their role in tumor growth can be analyzed through their corresponding proteolytic regulatory enzymes, which make them new and attractive therapeutic targets beyond the use or angiotensin converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs).

The role of the renin-angiotensin system inhibitors in malignancy: a review

Hypertension is one of the most prevalent diseases in cardiology. The angiotensin receptor blockers (ARBs)/angiotensin converting enzyme inhibitors (ACEIs) are widely used drugs to stabilize the blood pressure via inhibition of the renin-angiotensin system (RAS). Studies have found that the exposure to RAS inhibitors (RASi) can suppress the development of cancers via multimodal mechanisms and has attracted increased attentions in the recent past. Owing the potential of RASi to inhibit tumor growth, proliferation and metastasis, they are considered as the potential and exciting candidates to enhance the effect of chemo-radiotherapy and targeted therapy efficacy. However, there are conflicting reports as to the use of ARB/ACEI in all facets of tumor growth. In this study, we comprehensively summarize and review the potential mechanisms of RASi in cancer treatment, like inhibition of tumor angiogenesis, reduction of cancer-associated fibroblasts (CAFs) and extracellular matrix (ECM), regulation of immune cells and improvement of hypoxia. Additionally, based on the basic and clinical experiments, we analyze the views and results regarding the role of RASi plays in tumor from genesis to recurrence, and certainly cancer treatment (chemo-radiotherapy and targeted therapy). In the last, not only do we discuss the prospects of using RASi to enhance cancer treatment efficacy but also point out the conflicting situation with the intention to give some directions and inspiration on this topic.

Prevalence and impact of concomitant malignancy on outcomes among ambulatory heart failure population

INTRODUCTION

Heart failure (HF) and cancer are medical conditions with a rising prevalence resulting in increased co-occurrence. We assessed the impact of cancer on clinical outcome in patients with HF and the prognostic impact of specific types of cancers on different HF subpopulations.

METHODS

All patients with HF were evaluated for the occurrence of malignant neoplasm at a health maintenance organization and were followed for cardiac-related hospitalizations and death.

RESULTS

The study cohort included 7106 HF patients, 1564 of them (22%) had a diagnosis of malignant neoplasm. HF patients with concomitant cancer were older, had more comorbidities and were more likely to have NYHA class III/IV (42% vs. 37%, P < .01), compared with patients with no malignancy. The overall 2-year mortality rate of the entire HF cohort was 23.2%. Survival rate by Kaplan-Meier analysis demonstrated that the presence of a malignancy was directly associated with reduced survival: 67.2 ± 1.2% vs 79.5 ± 0.5%, P < .001. Malignancy was associated with an increase in mortality with a hazard ratio (HR) of 1.36, 95% confidence interval (CI) 1.21-1.54, P < .001. The strongest impact of malignancy on outcomes was related to age; among patients <70 years old, the increase in the risk of mortality was the highest with a HR of 2.07, 95% CI 1.54-2.80, P < .001.

CONCLUSIONS

Malignancy is common among patients with HF. Patients with concomitant HF and malignancies have poor outcomes, and the impact of cancer on outcome is stronger among young patients.

Cancer Stem Cells in Metastatic Head and Neck Cutaneous Squamous Cell Carcinoma Express Components of the Renin-Angiotensin System

We investigated the expression of components of the renin-angiotensin system (RAS) by cancer stem cell (CSC) subpopulations in metastatic head and neck cutaneous squamous cell carcinoma (mHNcSCC). Immunohistochemical staining demonstrated expression of prorenin receptor (PRR), angiotensin-converting enzyme (ACE), and angiotensin II receptor 2 (AT₂R) in all cases and angiotensinogen in 14 cases; however, renin and ACE2 were not detected in any of the 20 mHNcSCC tissue samples. Western blotting showed protein expression of angiotensinogen in all six mHNcSCC tissue samples, but in none of the four mHNcSCC-derived primary cell lines, while PRR was detected in the four cell lines only. RT-qPCR confirmed transcripts of angiotensinogen, PRR, ACE, and angiotensin II receptor 1 (AT₁R), but not renin or AT₂R in all four mHNcSCC tissue samples and all four mHNcSCC-derived primary cell lines, while ACE2 was expressed in the tissue samples only. Double immunohistochemical staining on two of the mHNcSCC tissue samples showed expression of angiotensinogen by the SOX2+ CSCs within the tumor nests (TNs), and immunofluorescence showed expression of PRR and AT₂R by the SOX2+ CSCs within the TNs and the peritumoral stroma (PTS). ACE was expressed on the endothelium of the tumor microvessels within the PTS. We demonstrated expression of angiotensinogen by CSCs within the TNs, PRR, and AT₂R by the CSCs within the TNs and the PTS, in addition to ACE on the endothelium of tumor microvessels in mHNcSCC.

Effect of angiotensin receptor blockers on the development of cancer: A nationwide cohort study in korea

The potential cancer risk associated with long‐term exposure to angiotensin receptor blockers (ARBs) is still unclear. We assessed the risk of incident cancer among hypertensive patients who were treated with ARBs compared with patients exposed to angiotensin‐converting enzyme inhibitors (ACEIs), which are known to have a neutral effect on cancer development. Using the Korean National Health Insurance Service database, we analyzed the data of patients diagnosed with essential hypertension from January 2005 to December 2012 who were aged ≥40 years, initially free of cancer, and were prescribed either ACEI or ARB (n = 293,962). Cox proportional hazard model adjusted for covariates was used to evaluate the risk of incident cancer. During a mean follow‐up of 10 years, 24,610 incident cancers were observed. ARB use was associated with a decreased risk of overall cancer compared with ACEI use (hazard ratio [HR] 0.76, 95% confidence interval [CI] 0.72‐0.80). Similar results were obtained for lung (HR 0.73, 95% CI 0.64‐0.82), hepatic (HR 0.56, 95% CI 0.48‐0.65), and gastric cancers (HR 0.74, 95% CI 0.66‐0.83). Regardless of the subgroup, greater reduction of cancer risk was seen among patients treated with ARB than that among patients treated with ACEIs. Particularly, the decreased risk of cancer among ARB users was more prominent among males and heavy drinkers (interaction P < .005). Dose‐response analyses demonstrated a gradual decrease in risk with prolonged ARB therapy than that with ACEI use. In conclusion, ARB use was associated with a decreased risk of overall cancer and several site‐specific cancers.

Renin-Angiotensin System in the Tumor Microenvironment

For enhancing the antitumor effects of current immunotherapies including immune-checkpoint blockade, it is important to reverse cancer-induced immunosuppression. The renin-angiotensin system (RAS) controls systemic body fluid circulation; however, the presence of a local RAS in tumors has been reported. Furthermore, the local RAS in tumors influences various immune and interstitial cells and affects tumor immune response. RAS stimulation through the angiotensin II type 1 receptor has been reported to inhibit tumor immune response. Therefore, RAS inhibitors and combined treatment with immunotherapy are expected in the future. In this chapter, we provide a background on the RAS and describe the tumor environment with regard to the RAS and tumor immune response.

Acetyl-CoA Synthetase 2: A Critical Linkage in Obesity-Induced Tumorigenesis in Myeloma

Obesity is often linked to malignancies including multiple myeloma, and the underlying mechanisms remain elusive. Here we showed that acetyl-CoA synthetase 2 (ACSS2) may be an important linker in obesity-related myeloma. ACSS2 is overexpressed in myeloma cells derived from obese patients and contributes to myeloma progression. We identified adipocyte-secreted angiotensin II as a direct cause of adiposity in increased ACSS2 expression. ACSS2 interacts with oncoprotein interferon regulatory factor 4 (IRF4), and enhances IRF4 stability and IRF4-mediated gene transcription through activation of acetylation. The importance of ACSS2 overexpression in myeloma is confirmed by the finding that an inhibitor of ACSS2 reduces myeloma growth both in vitro and in a diet-induced obese mouse model. Our findings demonstrate a key impact for obesity-induced ACSS2 on the progression of myeloma. Given the central role of ACSS2 in many tumors, this mechanism could be important to other obesity-related malignancies.

No influence on tumor growth by intramuscular injection of adipose-derived regenerative cells: safety evaluation of therapeutic angiogenesis with cell therapy

Therapeutic angiogenesis with autologous stem/progenitor cells is a promising novel strategy for treatment of severe ischemic diseases. Human clinical trials utilizing autologous adipose-derived regenerative cells (ADRCs) have not reported treatment-related critical adverse effects thus far. However, there is still a large knowledge gap regarding whether treatment of ischemic diseases with angiogenic therapy using ADRCs would promote unfavorable angiogenesis associated with tumors in vivo. Herein, we addressed this clinical question using a mouse hindlimb ischemia (HLI) and simultaneous remote tumor implantation model. C57BL/6J background wild-type mice were injected with murine B16F10 melanoma cells on their back, 1 day before ischemic surgery. These mice were subjected to surgical unilateral hindlimb ischemia, followed by ADRC implantation or PBS injection into the hindlimb ischemic muscles on the next day. Intramuscular implantation of ADRCs enhanced tissue capillary density and blood flow examined by a laser Doppler blood perfusion analysis in hind limb. However, this therapeutic regimen for ischemic limb using ADRCs did not affect remote melanoma growth nor the density of its feeder artery, angiogenesis, and lymphatic vessels compared with the PBS group. In addition, no distant metastases were detected in any of the mice regardless of the group. In conclusion, local implantation of ADRCs promotes angiogenesis in response to tissue ischemia in the hindlimb without promoting remote tumor growth and related angio/lymphangiogenesis. Therapeutic angiogenesis to the ischemic hindlimb using ADRCs seems to be safe regarding remote tumor growth.NEW & NOTEWORTHY In this study, we demonstrated that local injection of ADRCs can promote angiogenesis in response to tissue ischemia without promoting remote tumor growth in a mouse model. Our findings indicate that therapeutic angiogenesis to the ischemic hindlimb using ADRCs seems to be safe regarding remote tumor growth.

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.

Risk of lung cancer and renin-angiotensin blockade: a concise review

Purpose

The blockade of the renin–angiotensin–aldosterone system (RAAS) by angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs) is one of the most common treatments for hypertension, heart failure and renal diseases. However, concerns have been raised about a possible link between RAAS-blockers and an increased risk of cancer, particularly of lung cancer. This narrative review aims to give a critical appraisal of current evidence and to help physicians understand potential links between RAAS blockade and de novo lung cancer development.

Methods

Numerous pharmaco-epidemiologic studies, mostly retrospective cohort analyses, evaluated the association of RAAS blockade with lung cancer incidence and reported inconsistent findings. Meta-analyses could not further clarify a possible link between RAAS blockade and the risk of lung cancer.

Results

International regulatory agencies (FDA, EMA) have concluded that the use of RAAS blockers is not associated with an increased risk of developing lung cancer. Co-administration of RAAS blockers to systemic therapy of advanced non-small cell lung cancer seems to have positive effects on the outcome.

Conclusion

Until more comprehensive analyses have been completed, there is no need to change clinical practise. Additional prospective randomized trials with long-term follow-up are needed to investigate the effects of these drugs on the development and progression of lung cancer.

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.

Cancer Stem Cells in Head and Neck Metastatic Malignant Melanoma Express Components of the Renin-Angiotensin System

Components of the renin-angiotensin system (RAS) are expressed by cancer stem cells (CSCs) in many cancer types. We here investigated expression of the RAS by the CSC subpopulations in human head and neck metastatic malignant melanoma (HNmMM) tissue samples and HNmMM-derived primary cell lines. Immunohistochemical staining demonstrated expression of pro-renin receptor (PRR), angiotensin-converting enzyme (ACE), and angiotensin II receptor 2 (AT₂R) in all; renin in one; and ACE2 in none of the 20 HNmMM tissue samples. PRR was localized to cells within the tumor nests (TNs), while AT₂R was expressed by cells within the TNs and the peritumoral stroma (PTS). ACE was localized to the endothelium of the tumor microvessels within the PTS. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) detected transcripts for PRR, ACE, ACE2, and AT₁R, in all the five HNmMM tissue samples and four HNmMM-derived primary cell lines; renin in one tissue sample and one cell line, and AT₂R in none of the five HNmMM tissue samples and cell lines. Western blotting showed variable expression of ACE, PRR, and AT₂R, but not ACE2, in six HNmMM tissue samples and two HNmMM-derived primary cell lines. Immunofluorescence staining of two HNmMM tissue samples demonstrated expression of PRR and AT₂R by the SOX2+ CSCs within the TNs and the OCT4+ CSCs within the PTS, with ACE localized to the endothelium of the tumor microvessels within the PTS.

Targeting AGTR1/NF-κB/CXCR4 axis by miR-155 attenuates oncogenesis in glioblastoma

Glioblastoma (GBM) represents the most aggressive malignancy of the central nervous system. Increased expression of Angiotensin II Receptor Type 1 (AGTR1) has been associated with proliferative and infiltrative properties of glioma cells. However, the underlying mechanism of AGTR1 upregulation in GBM is still unexplored. To understand the post-transcriptional regulation of AGTR1 in GBM, we screened 3'untranslated region (3'UTR) of AGTR1 for putative miRNA binding by using prediction algorithms. Interestingly, miR-155 showed conserved binding on the 3'UTR of AGTR1, subsequently confirmed by luciferase reporter assay. Furthermore, miR-155 overexpressing GBM cells show decrease in AGTR1 expression accompanied with reduced cell proliferation, invasion, foci formation and anchorage-independent growth. Strikingly, immunodeficient mice implanted with stable miR-155 overexpressing SNB19 cells show negligible tumor growth. Notably, miR-155 attenuates NF-κB signaling downstream of AGTR1 leading to reduced CXCR4 as well as AGTR1 levels. Mechanistically, miR-155 mitigates AGTR1-mediated angiogenesis, epithelial-to-mesenchymal transition, stemness, and MAPK signaling. Similar effects were observed by using pharmacological inhibitor of IκB Kinase (IKK) complex in multiple cell-based assays. Taken together, we established that miRNA-155 post-transcriptionally regulates AGTR1 expression, abrogates AGTR1/NF-κB/CXCR4 signaling axis and elicits pleiotropic anticancer effects in GBM. This study opens new avenues for using IKK inhibitors and miRNA-155 replacement therapies for the treatment of AGTR1-positive malignancies.

Hepatocyte Growth Factor and Macrophage-stimulating Protein "Hinge" Analogs to Treat Pancreatic Cancer

Pancreatic cancer (PC) ranks twelfth in frequency of diagnosis but is the fourth leading cause of cancer related deaths with a 5 year survival rate of less than 7 percent. This poor prognosis occurs because the early stages of PC are often asymptomatic. Over-expression of several growth factors, most notably vascular endothelial growth factor (VEGF), has been implicated in PC resulting in dysfunctional signal transduction pathways and the facilitation of tumor growth, invasion and metastasis. Hepatocyte growth factor (HGF) acts via the Met receptor and has also received research attention with ongoing efforts to develop treatments to block the Met receptor and its signal transduction pathways. Macrophage-stimulating protein (MSP), and its receptor Ron, is also recognized as important in the etiology of PC but is less well studied. Although the angiotensin II (AngII)/AT1 receptor system is best known for mediating blood pressure and body water/electrolyte balance, it also facilitates tumor vascularization and growth by stimulating the expression of VEGF. A metabolite of AngII, angiotensin IV (AngIV) has sequence homology with the "hinge regions" of HGF and MSP, key structures in the growth factor dimerization processes necessary for Met and Ron receptor activation. We have developed AngIV-based analogs designed to block dimerization of HGF and MSP and thus receptor activation. Norleual has shown promise as tested utilizing PC cell cultures. Results indicate that cell migration, invasion, and pro-survival functions were suppressed by this analog and tumor growth was significantly inhibited in an orthotopic PC mouse model.

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.

Contribution of Macrophages and T Cells in Skeletal Metastasis

Bone is a common site for metastases with a local microenvironment that is highly conducive for tumor establishment and growth. The bone marrow is replete with myeloid and lymphoid linage cells that provide a fertile niche for metastatic cancer cells promoting their survival and growth. Here, we discuss the role of macrophages and T cells in pro- and anti-tumoral mechanisms, their interaction to support cancer cell growth, and their contribution to the development of skeletal metastases. Importantly, immunotherapeutic strategies targeting macrophages and T cells in cancer are also discussed in this review as they represent a great promise for patients suffering from incurable bone metastases.

Association between Angiotensin-Converting Enzyme Inhibitors and Lung Cancer-A Nationwide, Population-Based, Propensity Score-Matched Cohort Study

Background: Direct evidence of lung cancer risk in Asian users of angiotensin-converting enzyme inhibitors (ACEIs) is lacking. Methods: The ACEI cohort comprised 22,384 patients aged ≥ 18 years with a first prescription of ACEI. The comparison angiotensin receptor blocker (ARB) cohort consisted of age-, sex- and comorbidity-matched patients at a ratio of 1:1. The primary outcome was the incidence of lung cancer, which was evaluated using a proportional hazard model. Results: The overall incidence rates of lung cancer in the ACEI and ARB cohorts were 16.6 and 12.2 per 10,000 person-years, respectively. The ACEI cohort had a significantly higher risk of lung cancer than the ARB cohort (adjusted hazard ratio [aHR]. = 1.36; 95% confidence interval [CI]. = 1.11–1.67). Duration–response and dose–response analyses revealed that compared with patients who did not receive ACEIs, patients who received ACEIs for more than 45 days per year (aHR = 1.87; 95% CI = 1.48–2.36) and patients who received more than 540 defined daily doses of ACEIs per year (aHR =1.80; 95% CI = 1.43–-2.27) had a significantly higher risk of lung cancer. The cumulative incidence of lung cancer was also significantly higher in the ACEI cohort than in the ARB cohort (log-rank test, p = 0.002). Conclusions: ACEI use is associated with an increased risk of lung cancer compared with ARB use. Patients using ARBs have a significantly lower risk of lung cancer than non-ARB users.

Evaluating the benefits of renin-angiotensin system inhibitors as cancer treatments

G-protein-coupled receptors (GPCRs) are the largest and most diverse group of cellular membrane receptors identified and characterized. It is estimated that 30 to 50% of marketed drugs target these receptors. The angiotensin II receptor type 1 (AT1R) is a GPCR which signals in response to systemic alterations of the peptide hormone angiotensin II (AngII) in circulation. The enzyme responsible for converting AngI to AngII is the angiotensin-converting enzyme (ACE). Specific inhibitors for the AT1R (more commonly known as AT1R blockers or antagonists) and ACE are well characterized for their effects on the cardiovascular system. Combined with the extensive clinical data available on patient tolerance of AT1R blockers (ARBs) and ACE inhibitors (ACEIs), as well as their non-classical roles in cancer, the notion of repurposing this class of medications as cancer treatment(s) is explored in the current review. Given that AngII-dependent AT1R activity directly regulates angiogenesis, remodeling of vasculature, pro-inflammatory responses, stem cell programming and hematopoiesis, and electrolyte balance; the modulation of these processes with pharmacologically well characterized medications could present a valuable complementary treatment option for cancer patients.