Association of polymorphisms in angiotensin II receptor genes with aldosterone-producing adenoma

Exploring AT2R and its polymorphism in different diseases: An approach to develop AT2R as a drug target beyond hypertension

The Angiotensin II type 2 receptor (AT2R) is one of the critical components of the renin-angiotensin system (RAS), which performs diverse functions like inhibiting cell differentiation, cell proliferation, vasodilatation, reduces oxidative stress and inflammation. AT2R is relatively less studied in comparison to other components of RAS despite its uniqueness (sex-linked) and diverse functions. The AT2R is differentially expressed in different tissues, and its gene polymorphisms are associated with several diseases. The molecular mechanism behind the association of AT2R and its gene polymorphisms with the diseases remains to be fully understood, which hinders the development of AT2R as a drug target. Single nucleotide polymorphisms (SNPs) in AT2R are found at different locations (exons, introns, promoter, and UTR regions) and were studied for association with different diseases. There may be different mechanisms behind these associations as some AT2R SNP variants were associated with differential expression, the SNPs (A1675G/A1332G) affect the alternate splicing of AT2R mRNA, A1332G genotype results in shortening of the AT2R mRNA and subsequently defective protein. Few SNPs were found to be associated with the diseases in either females (C4599A) or males (T1334C). Several other SNPs were expected to be associated with other similar/related diseases, but studies have not been done yet. The present review emphasizes on the significance of AT2R and its polymorphisms associated with the diseases to explore the precise role of AT2R in different diseases and the possibility to develop AT2R as a potential drug target.

Germline Genetic Variants of the Renin-Angiotensin System, Hypoxia and Angiogenesis in Non-Small Cell Lung Cancer Progression: Discovery and Validation Studies

Simple Summary

The presence of polymorphic gene variants in the human genome provides extensive genetic (and eventually phenotypic) variation affecting both normal physiological mechanisms and cancer pathogenesis. Functional genetic polymorphisms might have predictive and/or prognostic value in lung cancer, opening novel opportunities to improve prediction and guide clinical reasoning and therapeutics in lung cancer patients. Recent knowledge pinpoints a pleiotropic role for renin-angiotensin system, particularly in the lung and mainly through locally regulated alternative molecules and secondary pathways. Dysregulation of this system play a role in cell proliferation, hypoxia and angiogenesis, which processes are involved in lung cancer progression. Here we suggest that polymorphic variants in genes coding for renin-angiotensin system might play a role in Non-Small Cell Lung Cancer progression.

Abstract

Introduction: The renin–angiotensin system (RAS) is involved in cell proliferation, immunoinflammatory response, hypoxia and angiogenesis, which are critical biological processes in lung cancer. Our aim was to study the association of putatively functional genetic polymorphisms in genes coding for proteins involved in RAS, hypoxia and angiogenesis with non-small cell lung cancer (NSCLC) prognosis. Methods: Genotyping of 52 germline variants from genes of the RAS and hypoxic/angiogenic factors/receptors was performed using MassARRAY iPLEX Gold in a retrospective cohort (n = 167) of advanced NSCLC patients. Validation of the resulting genetic markers was conducted in an independent group (n = 190), matched by clinicopathological characteristics. Results: Multivariate analysis on the discovery set revealed that MME rs701109 C carriers were protected from disease progression in comparison with homozygous T (hazard ratio (HR) = 0.5, 95% confidence interval (CI) = 0.2–0.8, p = 0.010). Homozygous A and T genotypes for KDR rs1870377 were at increased risk for disease progression and death compared to heterozygous (HR = 1.7, 95% CI = 1.2–2.5, p = 0.005 and HR = 2.1, 95% CI = 1.2–3.4, p = 0.006, respectively). Carriers of homozygous genotypes for ACE2 rs908004 presented increased risk for disease progression, only in the subgroup of patients without tumour actionable driver mutations (HR = 2.9, 95% CI = 1.3–6.3, p = 0.010). Importantly, the association of homozygous genotypes in MME rs701109 with risk for disease progression was confirmed after multivariate analysis in the validation set. Conclusion: This study provides evidence that MME polymorphism, which encodes neprilysin, may modulate progression-free survival in advanced NSCLC. Present genetic variation findings will foster basic, translational, and clinical research on their role in NSCLC.

Association of angiotensin ІІ type 1 receptor gene A1166C polymorphism with cancer risk: An updated meta-analysis

Objective:

The association between angiotensin II type 1 receptor (AGTR1) gene A1166C polymorphism and cancer risk has been investigated in many studies. However, the results have been inconclusive. A meta-analysis was performed to obtain a more precise estimation of the relationship.

Methods:

The PubMed and China National Knowledge Infrastructure databases were searched for published literature. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strengths of association.

Results:

Ten studies, including 1553 patients and 1904 controls, were included in the meta-analysis. Overall, there were no significant associations between the AGTR1 gene A1166C polymorphism and cancer risk in the general population (CC vs AA: OR = 1.09, 95% CI = 0.50–2.37; AC vs AA: OR = 1.54, 95% CI = 0.81–2.91; dominant model: OR = 1.46, 95% CI = 0.77–2.79; recessive model: OR = 1.12, 95% CI = 0.84–1.49). In a subgroup analysis by nationality and cancer type, the results also showed no association between this polymorphism and cancer risk.

Conclusions:

This meta-analysis demonstrated that the AGTR1 gene A1166C polymorphism does not appear to be related to the risk of cancer.

Gene Expression Profile of Persistent Postoperative Hypertension Patients with Aldosterone-producing Adenomas

Background:

Hypertension often persists after adrenalectomy for primary aldosteronism (PA). Many studies have analyzed the outcomes of adrenalectomy for aldosterone-producing adenomas (APA) to identify predictive factors for persistent hypertension. However, differentially expressed genes in persistent postoperative hypertension remain unknown. Our aim was to describe gene expression profile of persistent postoperative hypertension patients with APA.

Methods:

In this study, we described and compared gene expression profiles in persistent postoperative hypertension and postoperative normotension in Chinese patients with APA using microarray analysis. Confirmation was performed with quantitative real time-polymerase chain reaction analysis. Bioinformatic analysis (gene ontology analysis, pathway analysis and network analysis) was used for further research.

Results:

Microarray analysis identified a total of 99 differentially expressed genes, including 18 up-regulated and 81 down-regulated genes. Among the dysregulated genes were fat atypical cadherin 1 as well as fatty acid binding protein 4 and other genes that have not been previously studied in persistent postoperative hypertension with APA. Bioinformatics analysis indicated that differentially expressed genes were associated with lipid metabolic process, metal ion binding, and cell differentiation. Pathway analysis determined that five pathways corresponded to the dysregulated transcripts. The mRNAs-ncRNAs co-expression network was composed of 49 network nodes and 72 connections between 18 coding genes and 31 noncoding genes.

Conclusions:

This study revealed differentially expressed genes in persistent postoperative hypertension with APA and provided a resource of candidate genes for exploration of possible drug targets and prognostic markers.

Association of polymorphisms in AGTR1 and AGTR2 genes with primary aldosteronism in the Chinese Han population

HYPOTHESIS

Polymorphisms in angiotensin II type-1/2 receptor genes (AGTR1/AGTR2) may be involved in the pathogenesis of primary aldosteronism. The present study aims to reveal some loci susceptible to the disease on the genes in a group of Chinese Han nationality.

MATERIALS AND METHODS

A case-control study was conducted in 202 patients and 188 controls. Ten tagging SNPs on AGTR1/AGTR2 were genotyped for all subjects via the method of multiplex PCR-ligase detection reaction. Statistical analysis was performed with chi-square test and logistic regression analysis.

RESULTS

rs3772616 on the AGTR1 gene was a factor for susceptibility to primary aldosteronism (p<0.001), and the TT genotype significantly decreased the risk of primary aldosteronism compared with the CC homozygote (p=0.008, adjusted OR=0.13; 95%CI: 0.03-0.59). The rs3772616 polymorphism was associated with primary aldosteronism under the additive and dominant models. The female carriers of the G allele in rs5193 showed a significant difference compared with the T allele.

CONCLUSIONS

The AGTR1 rs3772616 polymorphism can be considered as a hereditary marker for primary aldosteronism, and in the Chinese Han population the rs5193 G allele seems to predispose to it only in women.

Association between single-nucleotide polymorphisms in six hypertensive candidate genes and hypertension among northern Han Chinese individuals

Hypertension is one of the leading risk factors for mortality. The renin-angiotensin-aldosterone system (RAAS) is a potent and powerful mediator in the homeostasis of hypertension. Here, the association between six candidate genes, renin, adrenoceptor β3, angiotensinogen, aldosterone synthase, angiotensin II receptor type 1 and angiotensin II receptor type 2, that are related to RAAS and essential hypertension (EH) was evaluated and explored in northern Chinese Han individuals. A case-control study including 1090 EH cases and 700 controls was performed. Eight single-nucleotide polymorphisms (SNPs), rs699, rs4762, rs5707, rs5186, rs4994, rs1799998, rs5193 and rs5194, located in the six genes were genotyped with TaqMan real-time PCR method. Statistical analysis software (SPSS 17.0) was used for descriptive statistics and association analyses. Among the six genes related to RAAS, the frequencies of rs4994 (ADRB3) and rs5194 (AGTR2) were found to be significantly different between the EH cases and controls (P < 0.05). Logistic regression analyses adjusted for covariates showed rs4994 to be closely associated with EH under the recessive (P = 0.019, odds ratio (OR) = 0.373, 95% confidence interval (CI) 0.163-0.851) and homozygous (P = 0.028, OR = 0.394, 95% CI 0.172-0.903) models. The association was also significantly close in the male subset (P < 0.05). Significant association was also observed between rs1799998 (CYP11B2) and EH (P < 0.05) in the dominant, additive and allelic models. These data demonstrated that ADRB3 rs4994 and CYP11B2 rs1799998 were significantly closely associated with EH in northern Han Chinese individuals. The CC of rs4994 and CC or C allele of rs1799998 might be protective genetic factors of hypertension.