The decrease of mineralcorticoid receptor drives angiogenic pathways in colorectal cancer

The multifaceted role of the mineralocorticoid receptor in cancers

The mineralocorticoid receptor (MR/NR3C2) is a member of the family of steroid receptors (SR) which also includes the estrogen receptor (ER), progesterone receptor (PR), androgen receptor (AR) and glucocorticoid receptor (GR). They function primarily as nuclear receptors to regulate gene expression. While the other steroid hormone receptors are known to play important roles in the pathogenesis and progression of many cancers, relatively little is understood about the role of MR in cancer biology. This review focuses on examining new insights into the potential roles and mechanisms of action of MR in cancers.

Mineralocorticoid receptor signaling inhibits bladder cancer progression

The biological or clinical significance of mineralocorticoid receptor (MR) in urothelial cancer remains largely unknown. The present study aimed to determine the functional role of MR in bladder cancer progression. In two of the human bladder cancer lines expressing MR, treatment with a natural MR ligand, aldosterone, significantly reduced cell proliferation and migration, which was restored by three MR antagonists clinically used, spironolactone (except colony formation of androgen receptor-positive cells cultured in the presence of androgens), eplerenone, and esaxerenone. Similarly, MR knockdown via shRNA virus infection resulted in significant increases in cell viability/migration, as well as colony formation, compared with control sublines. In addition, MR knockdown augmented the expression of β-catenin, c-fos, and N-cadherin, and lowered that of E-cadherin and p53, indicating the induction of the cadherin switching. Immunohistochemistry in surgical specimens detected MR signals in 58 (92.1%; 36.5% weakly-positive/1+, 44.4% moderately-positive/2+, and 11.1% strongly-positive/3+) of 63 muscle-invasive bladder cancers, which was significantly lower than in adjacent non-neoplastic urothelial tissues (100%; 15.7% 1+, 37.3% 2+, and 47.1% 3+). Moreover, patients with MR-high (3+) tumor had a significantly lower risk of cancer-specific mortality (P=0.039). Multivariable analysis further showed that strong MR expression was an independent predictor of cancer-specific survival in patients with muscle-invasive bladder cancer (hazard ratio 0.117, P=0.039). These findings suggest that MR signaling functions as a tumor suppressor in urothelial carcinoma and prevents tumor growth. Accordingly, there is a possibility that the concurrent use of anti-mineralocorticoids, particularly eplerenone and esaxerenone, in patients with bladder cancer rather contributes to the promotion of disease progression.

Genetic variants in the renin-angiotensin-aldosterone system: Impact on cancer risk, prognosis, and therapeutic directions

Although renin-angiotensin-aldosterone system (RAAS) is known to maintain blood pressure and electrolyte balance, it has recently been linked to a number of biological processes such as angiogenesis, tumorigenesis, metastasis, and cellular proliferation, increasing the risk of cancer development and progression. Multiple genetic variants have been found to affect the genes encoding RAAS components, altering gene transcription and protein expression. This review provides an up-to-date insight into the role of RAAS in carcinogenesis, as well as the impact of RAAS genetic variants on the risk of cancer development, progression, and patient survival and outcomes, as well as response to treatment. This paves the way for the application of precision medicine in cancer risk assessment and management by implementing preventative programs in individuals at risk and guiding the therapeutic direction in cancer patients.

Development and validation of a prognosis prediction model based on 18 endoplasmic reticulum stress-related genes for patients with lung adenocarcinoma

Background

Endoplasmic reticulum (ER) stress had a crucial impact on cell survival, proliferation, and metastasis in various cancers. However, the role of ER stress in lung adenocarcinoma remains unclear.

Method

Gene expression and clinical data of lung adenocarcinoma (LUAD) samples were extracted from The Cancer Genome Atlas (TCGA) and three Gene Expression Omnibus (GEO) datasets. ER stress score (ERSS) was constructed based on hub genes selected from 799 ER stress-related genes by least absolute shrinkage and selection operator (LASSO) regression. A Cox regression model, integrating ERSS and the TNM stage, was developed to predict overall survival (OS) in TCGA cohort and was validated in GEO cohorts. Gene set enrichment analysis (GSEA), single-sample GSEA (ssGSEA), and gene mutation analyses were performed to further understand the molecular features of ERSS. The tumor immune infiltration was evaluated by ESTIMATE, CIBERSORT, and xCell algorithms. The receiver operating characteristic (ROC) curves were used to evaluate the predictive value of the risk model. p< 0.05 was considered statistically significant.

Results

One hundred fifty-seven differentially expressed genes (DEGs) were identified between tumor and para-carcinoma tissues, and 45 of them significantly correlated with OS. Next, we identified 18 hub genes and constructed ERSS by LASSO regression. Multivariate analysis demonstrated that higher ERSS (p< 0.0001, hazard ratio (HR) = 3.8, 95%CI: 2.8–5.2) and TNM stage (p< 0.0001, HR = 1.55, 95%CI: 1.34–1.8) were independent predictors for worse OS. The prediction model integrating ERSS and TNM stage performed well in TCGA cohort (area under the curve (AUC) at five years = 0.748) and three GEO cohorts (AUC at 5 years = 0.658, 0.717, and 0.739). Pathway enrichment analysis showed that ERSS significantly correlated with unfolded protein response. Meanwhile, pathways associated with the cell cycle, growth, and metabolism were significantly enriched in the high ERSS group. Patients with SMARCA4, TP53, and EGFR mutations showed significantly higher ERSS (p = 4e−04, 0.0027, and 0.035, respectively). Tissues with high ERSS exhibited significantly higher infiltration of M1 macrophages, activated dendritic cells, and lower infiltration of CD8+ T cells and B cells, which indicate an activated tumor antigen-presenting but suppressive immune response status.

Conclusion

We developed and validated an ER stress-related risk model that exhibited great predictive value for OS in patients with LUAD. Our work also expanded the understanding of the role of ER stress in LUAD.

Nuclear receptor subfamily 3 group c member 2 (NR3C2) is downregulated due to hypermethylation and plays a tumor-suppressive role in colon cancer

Nuclear receptor subfamily 3 group c member 2 (NR3C2) has been reported to function as a tumor suppressor in several tumors. However, the clinical significance and potential action mechanisms of NR3C2 in colon cancer (COAD) remain unclear. NR3C2 expression and its correlation with clinicopathological features in COAD were analyzed based on the Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. Receiver operating characteristic (ROC) curves and Human Protein Atlas (HPA) database were used to evaluate the diagnostic and prognostic values of NR3C2 in COAD. Immune infiltration and DNA methylation analyses were performed by Gene Set Cancer Analysis (GSCA) database. NR3C2-correlated genes were identified by UALCAN database and subjected to gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment pathway analyses. Cell apoptosis and proliferation were evaluated using TUNEL and CCK-8 assays, respectively. NR3C2 was downregulated in COAD based on TCGA and GEO databases, which may be due to promoter hypermethylation. NR3C2 expression was correlated with prognosis and immune infiltration of COAD. High NR3C2 expression displayed good diagnostic value in COAD. KEGG pathway analysis presented that NR3C2-correlated genes were mainly clustered in choline metabolism in cancer and apoptosis. In vitro experiments confirmed that NR3C2 overexpression induced apoptosis and suppressed proliferation in COAD cells. In conclusion, our study revealed the potential prognostic and diagnostic values of NR3C2 and provided insights into understanding the tumor-suppressive role of NR3C2 in COAD progression.

NR3C2 suppresses the proliferation, migration, invasion and angiogenesis of colon cancer cells by inhibiting the AKT/ERK signaling pathway

Nuclear receptor subfamily 3, group C, member 2 (NR3C2) serves an antitumorigenic role in several types of cancer; however, its role and mechanisms of action in colon cancer remains to be elucidated. The aim of the present study was to explore the effects of NR3C2 on the proliferation, migration, invasion and angiogenesis of colon cancer cells. The expression levels of NR3C2 in human colon epithelial NCM460 cells (spontaneously immortalized cell line) and colon cancer cell lines was detected using reverse transcription-quantitative PCR and western blotting. Cell Counting Kit-8 (CCK-8) and colony formation assays were used to assess cell viability and wound healing and Transwell assays were used to detect cell invasion and migration. ELISA was used to detect the expression levels of VEGF and tube formation assays were used to assess angiogenesis. The expression levels of angiogenesis-related proteins and AKT/ERK signaling pathway-related proteins were detected by western blotting. NR3C2 expression was downregulated in colon cancer cells and overexpression of NR3C2 inhibited proliferation, colony formation, migration and invasion of colon cancer cells. Overexpression of NR3C2 inhibited angiogenesis and activity of the AKT/ERK signaling pathway in colon cancer cells. Thus, it was demonstrated that NR3C2 inhibited the proliferation, colony formation, migration, invasion and angiogenesis of colon cancer cells through the AKT/ERK signaling pathway. These results may highlight novel targets for the treatment of colon cancer.

Novel Insights into the Role of the Mineralocorticoid Receptor in Human Glioblastoma

The majority of glioblastoma (GBM) patients require the administration of dexamethasone (DEXA) to reduce brain inflammation. DEXA activates the glucocorticoid receptor (GR), which can consequently crosstalk with the mineralocorticoid receptor (MR). However, while GR signaling is well studied in GBM, little is known about the MR in brain tumors. We examined the implication of the MR in GBM considering its interplay with DEXA. Together with gene expression studies in patient cohorts, we used human GBM cell lines and patient-derived glioma stem cells (GSCs) to assess the impact of MR activation and inhibition on cell proliferation, response to radiotherapy, and self-renewal capacity. We show that in glioma patients, MR expression inversely correlates with tumor grade. Furthermore, low MR expression correlates with poorer survival in low grade glioma while in GBM the same applies to classical and mesenchymal subtypes, but not proneural tumors. MR activation by aldosterone suppresses the growth of some GBM cell lines and GSC self-renewal. In GBM cells, the MR antagonist spironolactone (SPI) can promote proliferation, radioprotection and cooperate with DEXA. In summary, we propose that MR signaling is anti-proliferative in GBM cells and blocks the self-renewal of GSCs. Contrary to previous evidence obtained in other cancer types, our results suggest that SPI has no compelling anti-neoplastic potential in GBM.

Targeting steroid hormone receptors for anti-cancer therapy-A review on small molecules and nanotherapeutic approaches

The steroid hormone receptors (SHRs) among nuclear hormone receptors (NHRs) are steroid ligand-dependent transcription factors that play important roles in the regulation of transcription of genes promoted via hormone responsive elements in our genome. Aberrant expression patterns and context-specific regulation of these receptors in cancer, have been routinely reported by multiple research groups. These gave an window of opportunity to target those receptors in the context of developing novel, targeted anticancer therapeutics. Besides the development of a plethora of SHR-targeting synthetic ligands and the availability of their natural, hormonal ligands, development of many SHR-targeted, anticancer nano-delivery systems and theranostics, especially based on small molecules, have been reported. It is intriguing to realize that these cytoplasmic receptors have become a hot target for cancer selective delivery. This is in spite of the fact that these receptors do not fall in the category of conventional, targetable cell surface bound or transmembrane receptors that enjoy over-expression status. Glucocorticoid receptor (GR) is one such exciting SHR that in spite of it being expressed ubiquitously in all cells, we discovered it to behave differently in cancer cells, thus making it a truly druggable target for treating cancer. This review selectively accumulates the knowledge generated in the field of SHR-targeting as a major focus for cancer treatment with various anticancer small molecules and nanotherapeutics on progesterone receptor, mineralocorticoid receptor, and androgen receptor while selectively emphasizing on GR and estrogen receptor. This review also briefly highlights lipid-modification strategy to convert ligands into SHR-targeted cancer nanotherapeutics. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Biology-Inspired Nanomaterials > Lipid-Based Structures Therapeutic Approaches and Drug Discovery > Emerging Technologies.

Weighted Gene Co-expression Network Analysis Identified a Novel Thirteen-Gene Signature Associated With Progression, Prognosis, and Immune Microenvironment of Colon Adenocarcinoma Patients

Colon adenocarcinoma (COAD) is one of the most common malignant tumors and has high migration and invasion capacity. In this study, we attempted to establish a multigene signature for predicting the prognosis of COAD patients. Weighted gene co-expression network analysis and differential gene expression analysis methods were first applied to identify differentially co-expressed genes between COAD tissues and normal tissues from the Cancer Genome Atlas (TCGA)-COAD dataset and GSE39582 dataset, and a total of 309 overlapping genes were screened out. Then, our study employed TCGA-COAD cohort as the training dataset and an independent cohort by merging the GES39582 and GSE17536 datasets as the testing dataset. After univariate and multivariate Cox regression analyses were performed for these overlapping genes and overall survival (OS) of COAD patients in the training dataset, a 13-gene signature was constructed to divide COAD patients into high- and low-risk subgroups with significantly different OS. The testing dataset exhibited the same results utilizing the same predictive signature. The area under the curve of receiver operating characteristic analysis for predicting OS in the training and testing datasets were 0.789 and 0.868, respectively, which revealed the enhanced predictive power of the signature. Multivariate Cox regression analysis further suggested that the 13-gene signature could independently predict OS. Among the 13 prognostic genes, NAT1 and NAT2 were downregulated with deep deletions in tumor tissues in multiple COAD cohorts and exhibited significant correlations with poorer OS based on the GEPIA database. Notably, NAT1 and NAT2 expression levels were positively correlated with infiltrating levels of CD8+ T cells and dendritic cells, exhibiting a foundation for further research investigating the antitumor immune roles played by NAT1 and NAT2 in COAD. Taken together, the results of our study showed that the 13-gene signature could efficiently predict OS and that NAT1 and NAT2 could function as biomarkers for prognosis and the immune response in COAD.

Network pharmacology and molecular docking study on the mechanism of colorectal cancer treatment using Xiao-Chai-Hu-Tang

BACKGROUND AND OBJECTIVE

We aimed to predict the targets and signal pathways of Xiao-Chai-Hu-Tang (XCHT) in the treatment of colorectal cancer (CRC) based on network pharmacology, just as well as to further analyze its anti-CRC material basis and mechanism of action.

METHODS

We adopted Traditional Chinese Medicine Systems Pharmacology Database (TCMSP) and Traditional Chinese Medicine Integrated Database (TCMID) databases to screen the active ingredients and potential targets of XCHT. CRC-related targets were retrieved by analyzing published microarray data (accession number GSE110224) from the Gene Expression Omnibus (GEO) database. The common targets were used to construct the "herb-active ingredient-target" network using the Cytoscape 3.8.0 software. Next, we constructed and analyzed protein-to-protein interaction (PPI) using BisoGenet and CytoNCA plug-in in Cytoscape. We then performed Gene Ontology (GO) functional and the Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathway enrichment analyses of target genes using the R package of clusterProfiler. Furthermore, we used the AutoDock Tools software to conduct molecular docking studies on the active ingredients and key targets to verify the network pharmacological analysis results.

RESULTS

We identified a total of 71 active XCHT ingredients and 20 potential anti-CRC targets. The network analysis revealed quercetin, stigmasterol, kaempferol, baicalein, and acacetin as potential key compounds, and PTGS2, NR3C2, CA2, and MMP1 as potential key targets. The active ingredients of XCHT interacted with most CRC disease targets. We showed that XCHT's therapeutic effect was attributed to its synergistic action (multi-compound, multi-target, and multi-pathway). Our GO enrichment analysis showed 46 GO entries, including 20 biological processes, 6 cellular components, and 20 molecular functions. We identified 11 KEGG signaling pathways, including the IL-17, TNF, Toll-like receptor, and NF-kappa B signaling pathways. Our results showed that XCHT could play a role in CRC treatment by regulating different signaling pathways. The molecular docking experiment confirmed the correlation between five core compounds (quercetin, stigmasterol, kaempferol, baicalein, and acacetin) just as well as PTGS2, NR3C2, CA2, and MMP1.

CONCLUSION

In this study, we described the potential active ingredients, possible targets, and key biological pathways responsible for the efficacy of XCHT in CRC treatment, providing a theoretical basis for further research.

miR-301b and NR3C2 co-regulate cells malignant properties and have the potential to be independent prognostic factors in breast cancer

This study intends to address the function of miR-301b/nuclear receptor subfamily 3 group C member 2 (NR3C2) in breast cancer. The Cancer Genome Atlas database was processed to investigate the expression of miR-301b/NR3C2 in breast cancer samples, as well as the relationship between their expression and the prognosis of the patients. Cox regression analysis was performed to determine whether miR-301b/NR3C2 was an independent predictor of the patient's prognosis. Associations between miR-301b and NR3C2 were analyzed by prediction website, dual-luciferase assay, and Pearson correlation coefficient. Quantitative polymerase chain reaction and Western blot analyses were implemented to detect gene expression. The relevant biological characteristics of MCF7 and BCAP-37 cells were tested by cell counting kit-8, colony formation, and transwell assays. Lower expression of NR3C2, which was closely related to the bad prognosis of breast cancer patients, was presented in breast cancer samples and can be used as an independent predictor. miR-301b, as an upstream regulator of NR3C2, was highly expressed in breast cancer samples and can be used as an independent predictor as well. Notably, a higher level of miR-301b and lower level of NR3C2 were related to the reduced overall survival in patients with breast cancer. The proliferative and migratory behaviors of cells were elevated or blocked after overexpression of miR-301b or NR3C2, respectively. However, the above situation was attenuated after together upregulation of miR-301b and NR3C2. The present data afforded evidence that miR-301b may be a tumor-promoting miRNA in breast cancer, and that miR-301b/NR3C2 axis mediated tumor development from cell proliferation and migration.

miR-301b-3p Regulates Breast Cancer Cell Proliferation, Migration, and Invasion by Targeting NR3C2

Objectives

Breast cancer is the most common malignant tumor among females, and miRNAs have been reported to play an important regulatory role in breast cancer progression. This study aimed to explore the function and underlying molecular mechanism of miR-301b-3p in breast cancer.

Methods

Differential analysis and survival analysis were performed based on the data accessed from the TCGA-BRCA dataset for identification of the target miRNA. Bioinformatics analysis was conducted to predict the downstream target gene of the miRNA. Real-time quantitative PCR was carried out to detect the expression of miR-301b-3p and nuclear receptor subfamily 3 group C member 2 (NR3C2). Western blot was used to assess the protein expression of NR3C2. Cell counting kit-8 assay was performed to evaluate the proliferation of breast cancer cells. Transwell assay was conducted to determine the migratory and invasive abilities of breast cancer cells. Dual-luciferase reporter assay was employed to verify the targeting relationship between miR-301b-3p and NR3C2.

Results

miR-301b-3p was elevated in breast cancer cell lines and promoted cell proliferation, migration, and invasion in terms of its biological function in breast cancer. NR3C2 was validated as a direct target of miR-301b-3p via bioinformatics analysis and dual-luciferase reporter assay, and NR3C2 was downregulated in breast cancer cell lines. The rescue experiment indicated that NR3C2 was involved in the mechanism by which miR-301b-3p regulated the malignant phenotype of breast cancer cells.

Conclusion

The present study revealed for the first time that miR-301b-3p could foster breast cancer cell proliferation, migration, and invasion by targeting NR3C2, unveiling that miR-301b-3p is a novel carcinogen in breast cancer.

CREB1-induced miR-1204 promoted malignant phenotype of glioblastoma through targeting NR3C2

Background

Glioblastoma (GBM) is a subclass of brain malignancy with unsatisfactory prognosis. MicroRNAs (miRNAs) are a group of non-coding RNAs (ncRNAs) that exert key function on tumorigenesis and tumor development.

Purposes

The purpose of this work was to unravel the biological behavior and mechanism of miR-1204 in GBM.

Methods

Expressions of miR-1204, NR3C2 and CREB1 were detected by RT-qPCR and western blot. Proliferation and apoptosis of GBM cells were detected by CCK-8, colony formation, caspase-3 activity and TUNEL assays. Molecular interplays were examined by ChIP, RIP, and luciferase reporter assays.

Results

MiR-1204 level was elevated in GBM cell lines. Functionally, miR-1204 aggravated cell proliferation whereas suppressed cell apoptosis in GBM cells. Mechanistically, cAMP Responsive Element Binding Protein 1 (CREB1) bound to the promoter of miR-1204 and activated the transcription of miR-1204. Furthermore, miR-1204 targeted and inhibited Nuclear receptor subfamily 3 group C member 2 (NR3C2), a tumor suppressor gene in GBM cells. Rescue assays indicated that NR3C2 participated in the regulation of miR-1204 on the malignant phenotype of GBM cells.

Conclusions

We observed for the first time that CREB1-induced miR-1204 promoted malignant phenotype of GBM through targeting NR3C2, indicating that miR-1204 acted as a novel oncogenic miRNA in GBM.

miR-454 performs tumor-promoting effects in oral squamous cell carcinoma via reducing NR3C2

BACKGROUND

Aberrant miRNAs expression regulates the occurrence and progression of a variety of cancers, including oral squamous cell carcinoma (OSCC). This study aims to illustrate the potential effects of miR-454/nuclear receptor subfamily 3 group C member 2 (NR3C2) on the biological behaviors of OSCC cells.

METHODS

GEO database was applied to detect and analyze the expression of miR-545 and NR3C2 in OSCC tissues. Two OSCC cell lines including CAL27 and Tca-83 were utilized to determine the function of miR-454/NR3C2 on OSCC cells biological behaviors. miR-454 and NR3C2 expressions were regulated by miR-454 mimic/inhibitor and pcDNA3.1-NR3C2/si-NR3C2, respectively. Cells biological behaviors were evaluated by cell proliferation, colony formation, and transwell assays.

RESULTS

The data collected from GEO database indicated that miR-454 expression was upregulated in OSCC tissues; however, the expression of NR3C2 assumed a downward trend. In vitro experiments, the expression trend of miR-454 in OSCC cell lines was consistent with that of the trend in tissues, and the OSCC cells growth and movement abilities significantly decreased after miR-454 depletion. Through co-transfection experiments, we explored that the abilities of OSCC cell proliferation, colony formation, invasion, and migration obviously reduced after miR-454 depletion, but these phenomena were mitigated to some extent after NR3C2 silencing.

CONCLUSION

The study illustrates that miR-454 acts as an active regulator to facilitate OSCC cells growth, colony formation, invasion, and migration by targeting NR3C2, which may afford a novel perspective and possibility for the targeted treatment of OSCC.

miR-4709 overexpression facilitates cancer proliferation and invasion via downregulating NR3C2 and is an unfavorable prognosis factor in colon adenocarcinoma

To date, microRNA-4709 (miR-4709) has not been studied in colon adenocarcinoma (COAD) on the basis of experiments. In our study, we aimed to investigate the biological roles and clinical significance of miR-4709 in COAD. The expression difference between miR-4709 and NR3C2 was measured based on The Cancer Genome Atlas database and cells. Kaplan-Meier and logrank tests were applied to determine the overall survival (OS) differences according to the miR-4709 and NR3C2 expression levels. To measure whether the miR-4709 level was associated with COAD cell growth, migration, and invasion, we respectively conducted 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, wound healing, and transwell assays. A luciferase reporter assay was applied to confirm the relationship between miR-4709 and its predicted target. High expression of miR-4709 was found in COAD tissues and cells. The OS rate in the miR-4709 low expression group was significantly higher than that in the miR-4709 high expression group. Univariate and multivariate analyses exhibited that miR-4709 expression was an independent adverse prognostic factor. Exogenous miR-4709 overexpression promoted proliferation, migration, and invasion of LOVO and SW480 cells. Bioinformatics analysis and luciferase assay demonstrated that miR-4709 directly binds to the 3'-untranslated region of NR3C2. NR3C2 was lowly expressed in COAD and high expression of NR3C2 had a better prognosis compared with that in the low expression of NR3C2. Correlation analysis showed that there is a close association between the level of expression of NR3C2 and miR-4709. Accordingly, miR-4709 may function as an oncogene in COAD and provide a preclinical proof for candidate management to target new miR-4709-NR3C2 signaling for COAD therapy.

Glucocorticoid-mediated effects on angiogenesis in solid tumors

Angiogenesis is essential in tumor development to maintain the oxygen and nutrient supply. Glucocorticoids have shown both direct and indirect angiostatic properties in various types of solid cancers. In most of the reported cases glucocorticoid-mediated actions involved suppression of multiple pro-angiogenic factors expression by cancer cells. The anti-angiogenic properties of glucocorticoids correlated with diminished tumor vasculature and reduced tumor growth in multiple in vivo studies. However, when glucocorticoid treatment is considered, possible adverse events should be taken into account. Additional research is needed to further test the use of these steroidal drugs in cancer therapy.

FoPA: identifying perturbed signaling pathways in clinical conditions using formal methods

BACKGROUND

Accurate identification of perturbed signaling pathways based on differentially expressed genes between sample groups is one of the key factors in the understanding of diseases and druggable targets. Most pathway analysis methods prioritize impacted signaling pathways by incorporating pathway topology using simple graph-based models. Despite their relative success, these models are limited in describing all types of dependencies and interactions that exist in biological pathways.

RESULTS

In this work, we propose a new approach based on the formal modeling of signaling pathways. Signaling pathways are formally modeled, and then model checking tools are applied to find the likelihood of perturbation for each pathway in a given condition. By adopting formal methods, various complex interactions among biological parts are modeled, which can contribute to reducing the false-positive rate of the proposed approach. We have developed a tool named Formal model checking based pathway analysis (FoPA) based on this approach. FoPA is compared with three well-known pathway analysis methods: PADOG, CePa, and SPIA on the benchmark of 36 GEO datasets from various diseases by applying the target pathway technique. This validation technique eliminates the need for possibly biased human assessments of results. In the cases that, there is no apriori knowledge of all relevant pathways, simulated false inputs (permuted class labels and decoy pathways) are chosen as a set of negative controls to test the false positive rate of the methods. Finally, to further evaluate the efficiency of FoPA, it is applied to a list of autism-related genes.

CONCLUSIONS

The results obtained by the target pathway technique demonstrate that FoPA is able to prioritize target pathways as well as PADOG but better than CePa and SPIA. Also, the false-positive rate of finding significant pathways using FoPA is lower than other compared methods. Also, FoPA can detect more consistent relevant pathways than other methods. The results of FoPA on autism-related genes highlight the role of "Renin-angiotensin system" pathway. This pathway has been supposed to have a pivotal role in some neurodegenerative diseases, while little attention has been paid to its impact on autism development so far.

Heteropolymerization of α-1-antitrypsin mutants in cell models mimicking heterozygosity

The most common genotype associated with severe α-1-antitrypsin deficiency (AATD) is the Z homozygote. The Z variant (Glu342Lys) of α-1-antitrypsin (AAT) undergoes a conformational change and is retained within the endoplasmic reticulum (ER) of hepatocytes leading to the formation of ordered polymeric chains and inclusion bodies. Accumulation of mutated protein predisposes to cirrhosis whilst plasma AAT deficiency leads to emphysema. Increased risk of liver and lung disease has also been reported in heterozygous subjects who carry Z in association with the milder S allele (Glu264Val) or even with wild-type M. However, it is unknown whether Z AAT can co-polymerize with other AAT variants in vivo. We co-expressed two AAT variants, each modified by a different tag, in cell models that replicate AAT deficiency. We used pull-down assays to investigate interactions between co-expressed variants and showed that Z AAT forms heteropolymers with S and with the rare Mmalton (Phe52del) and Mwurzburg (Pro369Ser) mutants, and to a lesser extent with the wild-type protein. Heteropolymers were recognized by the 2C1 mAb that binds to Z polymers in vivo. There was increased intracellular accumulation of AAT variants when co-expressed with Z AAT, suggesting a dominant negative effect of the Z allele. The molecular interactions between S and Z AAT were confirmed by confocal microscopy showing their colocalization within dilated ER cisternae and by positivity in Proximity Ligation Assays. These results provide the first evidence of intracellular co-polymerization of AAT mutants and contribute to understanding the risk of liver disease in SZ and MZ heterozygotes.

Characterisation of a type II functionally-deficient variant of alpha-1-antitrypsin discovered in the general population

Lung disease in alpha-1-antitrypsin deficiency (AATD) results from dysregulated proteolytic activity, mainly by neutrophil elastase (HNE), in the lung parenchyma. This is the result of a substantial reduction of circulating alpha-1-antitrypsin (AAT) and the presence in the plasma of inactive polymers of AAT. Moreover, some AAT mutants have reduced intrinsic activity toward HNE, as demonstrated for the common Z mutant, as well as for other rarer variants. Here we report the identification and characterisation of the novel AAT reactive centre loop variant Gly349Arg (p.G373R) present in the ExAC database. This AAT variant is secreted at normal levels in cellular models of AATD but shows a severe reduction in anti-HNE activity. Biochemical and molecular dynamics studies suggest it exhibits unfavourable RCL presentation to cognate proteases and compromised insertion of the RCL into β-sheet A. Identification of a fully dysfunctional AAT mutant that does not show a secretory defect underlines the importance of accurate genotyping of patients with pulmonary AATD manifestations regardless of the presence of normal levels of AAT in the circulation. This subtype of disease is reminiscent of dysfunctional phenotypes in anti-thrombin and C1-inibitor deficiencies so, accordingly, we classify this variant as the first pure functionally-deficient (type II) AATD mutant.

Endothelial cell mineralocorticoid receptors oppose VEGF-induced gene expression and angiogenesis

Aldosterone is a key factor in adverse cardiovascular remodeling by acting on the mineralocorticoid receptor (MR) in different cell types. Endothelial MR activation mediates hypertrophy, inflammation and fibrosis. Cardiovascular remodeling is often accompanied by impaired angiogenesis, which is a risk factor for the development of heart failure. In this study, we evaluated the impact of MR in endothelial cells on angiogenesis. Deoxycorticosterone acetate (DOCA)-induced hypertension was associated with capillary rarefaction in the heart of WT mice but not of mice with cell type-specific MR deletion in endothelial cells. Consistently, endothelial MR deletion prevented the inhibitory effect of aldosterone on the capillarization of subcutaneously implanted silicon tubes and on capillary sprouting from aortic ring segments. We examined MR-dependent gene expression in cultured endothelial cells by RNA-seq and identified a cluster of differentially regulated genes related to angiogenesis. We found opposing effects on gene expression when comparing activation of the mineralocorticoid receptor in ECs to treatment with vascular endothelial growth factor (VEGF), a potent activator of angiogenesis. In conclusion, we demonstrate here that activation of endothelial cell MR impaired angiogenic capacity and lead to capillary rarefaction in a mouse model of MR-driven hypertension. MR activation opposed VEGF-induced gene expression leading to the dysregulation of angiogenesis-related gene networks in endothelial cells. Our findings underscore the pivotal role of endothelial cell MR in the pathophysiology of hypertension and related heart disease.

Potential endocrine-disrupting effects of metals via interference with glucocorticoid and mineralocorticoid receptors

As a result of human activities, the pollution of metals is becoming ubiquitous in the environment. Among various toxicological mechanisms of action, metals have been considered as endocrine-disrupting chemicals (EDCs) through interference with steroid receptors. However, information regarding the potential endocrine disruption of metals on glucocorticoid receptor (GR) and mineralocorticoid receptor (MR) is especially scarce. In this study, a total of 16 metals were assessed for their GR/MR activities using luciferase reporter gene assay. None of the tested metals exhibited GR or MR agonistic activity, but a total of 7 and 5 candidate metals showed obvious GR and MR antagonistic properties, respectively. All 7 GR antagonistic metals [ BaCl₂, CoCl₂, CuCl₂, Pb(NO₃)₂, LiCl, SnCl₂ and ZnCl₂] inhibited glucocorticoid-responsive gene GILZ expression in J774A.1 cells. Further investigations indicated that the 5 MR antagonistic metals [ CdCl₂, Pb(NO₃)₂, LiCl, MnCl₂ and SnCl₂] antagonized aldosterone-inhibited hepatocellular carcinoma cell proliferation. Among these metals, Pb(NO₃)₂, LiCl, and SnCl₂ showed both anti-glucocorticoid and anti-mineralocorticoid activities. Comprehensive screening and evaluation of GR and MR antagonists and agonists among metals should be considered to better understand the ecological and health risks of metals.

A Novel MIF Signaling Pathway Drives the Malignant Character of Pancreatic Cancer by Targeting NR3C2

Pancreatic cancers with aberrant expression of macrophage migration inhibitory factor (MIF) are particularly aggressive. To identify key signaling pathways that drive disease aggressiveness in tumors with high MIF expression, we analyzed the expression of coding and noncoding genes in high and low MIF-expressing tumors in multiple cohorts of pancreatic ductal adenocarcinoma (PDAC) patients. The key genes and pathways identified were linked to patient survival and were mechanistically, functionally, and clinically characterized using cell lines, a genetically engineered mouse model, and PDAC patient cohorts. Here, we report evidence of a novel MIF-driven signaling pathway that inhibits the orphan nuclear receptor NR3C2, a previously undescribed tumor suppressor that impacts aggressiveness and survival in PDAC. Mechanistically, MIF upregulated miR-301b that targeted NR3C2 and suppressed its expression. PDAC tumors expressing high levels of MIF displayed elevated levels of miR-301b and reduced levels of NR3C2. In addition, reduced levels of NR3C2 expression correlated with poorer survival in multiple independent cohorts of PDAC patients. Functional analysis showed that NR3C2 inhibited epithelial-to-mesenchymal transition and enhanced sensitivity to the gemcitabine, a chemotherapeutic drug used in PDAC standard of care. Furthermore, genetic deletion of MIF disrupted a MIF-mir-301b-NR3C2 signaling axis, reducing metastasis and prolonging survival in a genetically engineered mouse model of PDAC. Taken together, our results offer a preclinical proof of principle for candidate therapies to target a newly described MIF-miR-301b-NR3C2 signaling axis for PDAC management. Cancer Res; 76(13); 3838-50. ©2016 AACR.

The effects of transfection reagent polyethyleneimine (PEI) and non-targeting control siRNAs on global gene expression in human aortic smooth muscle cells

BACKGROUND

RNA interference (RNAi) is a powerful platform utilized to target transcription of specific genes and downregulate the protein product. To achieve effective silencing, RNAi is usually applied to cells or tissue with a transfection reagent to enhance entry into cells. A commonly used control is the same transfection reagent plus a "noncoding RNAi". However, this does not control for the genomic response to the transfection reagent alone or in combination with the noncoding RNAi. These control effects while not directly targeting the gene in question may influence expression of other genes that in turn alter expression of the target. The current study was prompted by our work focused on prevention of vascular bypass graft failure and our experience with gene silencing in human aortic smooth muscle cells (HAoSMCs) where we suspected that off target effects through this mechanism might be substantial. We have used Next Generation Sequencing (NGS) technology and bioinformatics analysis to examine the genomic response of HAoSMCs to the transfection reagent alone (polyethyleneimine (PEI)) or in combination with commercially obtained control small interfering RNA (siRNAs) (Dharmacon and Invitrogen).

RESULTS

Compared to untreated cells, global gene expression of HAoSMcs after transfection either with PEI or in combination with control siRNAs displayed significant alterations in gene transcriptome after 24 h. HAoSMCs transfected by PEI alone revealed alterations of 213 genes mainly involved in inflammatory and immune responses. HAoSMCs transfected by PEI complexed with siRNA from either Dharmacon or Invitrogen showed substantial gene variation of 113 and 85 genes respectively. Transfection of cells with only PEI or with PEI and control siRNAs resulted in identification of 20 set of overlapping altered genes. Further, systems biology analysis revealed key master regulators in cells transfected with control siRNAs including the cytokine, Interleukin (IL)-1, transcription factor GATA Binding Protein (GATA)-4 and the methylation enzyme, Enhancer of zeste homolog 2 (EZH-2) a cytokine with an apical role in initiating the inflammatory response.

CONCLUSIONS

Significant off-target effects in HAoSMCs transfected with PEI alone or in combination with control siRNAs may lead to misleading conclusions concerning the effectiveness of a targeted siRNA strategy. The lack of structural information about transfection reagents and "non coding" siRNA is a hindrance in the development of siRNA based therapeutics.

Mineralocorticoid receptor suppresses cancer progression and the Warburg effect by modulating the miR-338-3p-PKLR axis in hepatocellular carcinoma

Hormones and their corresponding receptors are vital in controlling metabolism under normal physiologic and pathologic conditions, but less is known about their roles in the metabolism of cancer. Using a small interfering RNA screening approach, we examined the effects of silencing 20 well-known hormone receptors on the Warburg effect, specifically by measuring the production of lactate in four established hepatocellular carcinoma (HCC) cell lines. We found that silencing a variety of hormone receptors had effects on the production of this metabolite. Unexpectedly silencing of mineralocorticoid receptor (MR) significantly increased lactate production in all these HCC cell lines. Subsequent in vitro and in vivo studies showed that gain- and loss-of-function of MR significantly influenced HCC cellular proliferation, cell cycle distribution, and apoptosis. Furthermore, mechanistic studies revealed that MR as a transcriptional factor directly regulated the expression of miR-338-3p, suppressing the Warburg effects of HCC cells by targeting a key enzyme of glycolysis: pyruvate kinase, liver and red blood cells. Moreover, MR expression was significantly down-regulated in 81% of HCC patient tissues, caused by both chromosome deletion and histone deacetylation. Low expression of MR in tumor tissues was associated with poor patient prognosis. The expression level of miR-338-3p was found to positively correlate with the expression of MR in HCC tissues and to inversely correlate with expression of the enzyme pyruvate kinase, liver and red blood cells.

CONCLUSION

MR affects HCC development by modulating the miR-338-3p/pyruvate kinase, liver and red blood cells axis with an ability to suppress the Warburg effect.

Aldosterone promotes cardiac endothelial cell proliferation in vivo

BACKGROUND

Experimentally, aldosterone in association with NaCl induces cardiac fibrosis, oxidative stress, and inflammation through mineralocorticoid receptor activation; however, the biological processes regulated by aldosterone alone in the heart remain to be identified.

METHODS AND RESULTS

Mice were treated for 7 days with aldosterone, and then cardiac transcriptome was analyzed. Aldosterone regulated 60 transcripts (51 upregulated and 9 downregulated) in the heart (fold change ≥1.5, false discovery rate <0.01). To identify the biological processes modulated by aldosterone, a gene ontology analysis was performed. The majority of aldosterone-regulated genes were involved in cell division. The cardiac Ki-67 index (an index of proliferation) of aldosterone-treated mice was higher than that of nontreated mice, confirming microarray predictions. Costaining of Ki-67 with vinculin, CD68, α-smooth muscle actin, CD31, or caveolin 1 revealed that the cycling cells were essentially endothelial cells. Aldosterone-induced mineralocorticoid receptor-dependent proliferation was confirmed ex vivo in human endothelial cells. Moreover, pharmacological-specific blockade of mineralocorticoid receptor by eplerenone inhibited endothelial cell proliferation in a preclinical model of heart failure (transverse aortic constriction).

CONCLUSIONS

Aldosterone modulates cardiac gene expression and induces the proliferation of cardiac endothelial cells in vivo.

Crystal structure of the mineralocorticoid receptor DNA binding domain in complex with DNA

The steroid hormone receptors regulate important physiological functions such as reproduction, metabolism, immunity, and electrolyte balance. Mutations within steroid receptors result in endocrine disorders and can often drive cancer formation and progression. Despite the conserved three-dimensional structure shared among members of the steroid receptor family and their overlapping DNA binding preference, activation of individual steroid receptors drive unique effects on gene expression. Here, we present the first structure of the human mineralocorticoid receptor DNA binding domain, in complex with a canonical DNA response element. The overall structure is similar to the glucocorticoid receptor DNA binding domain, but small changes in the mode of DNA binding and lever arm conformation may begin to explain the differential effects on gene regulation by the mineralocorticoid and glucocorticoid receptors. In addition, we explore the structural effects of mineralocorticoid receptor DNA binding domain mutations found in type I pseudohypoaldosteronism and multiple types of cancer.