Endothelin-3 is epigenetically silenced in endometrioid endometrial cancer.

PURPOSE: Changes in the activity of endothelins and their receptors may promote neoplastic processes. They can be caused by epigenetic modifications and modulators, but little is known about endothelin-3 (EDN3), particularly in endometrial cancer. The aim of the study was to determine the expression profile of endothelin family and their interactions with miRNAs, and to assess the degree of EDN3 methylation. METHODS: The study enrolled 45 patients with endometrioid endometrial cancer and 30 patients without neoplastic changes. The expression profile of endothelins and their receptors was determined with mRNA microarrays and RT-qPCR. The miRNA prediction was based on the miRNA microarray experiment and the mirDB tool. The degree of EDN3 methylation was assessed by MSP. RESULTS: EDN1 and EDNRA were overexpressed regardless of endometrial cancer grade, which may be due to the lack of regulatory effect of miR-130a-3p and miR-485-3p, respectively. In addition, EDN3 and EDNRB were significantly downregulated. CONCLUSION: The endothelial axis is disturbed in endometrioid endometrial cancer. The observed silencing of EDN3 activity may be mainly due to DNA methylation.

Bombesin, endothelin, neurotensin and pituitary adenylate cyclase activating polypeptide cause tyrosine phosphorylation of receptor tyrosine kinases.

Numerous peptides including bombesin (BB), endothelin (ET), neurotensin (NTS) and pituitary adenylate cyclase-activating polypeptide (PACAP) are growth factors for lung cancer cells. The peptides bind to G protein-coupled receptors (GPCRs) resulting in elevated cAMP and/or phosphatidylinositol (PI) turnover. In contrast, growth factors such as epidermal growth factor (EGF) or neuregulin (NRG)-1 bind to receptor tyrosine kinases (RTKs) such as the EGFR or HER3, increasing tyrosine kinase activity, resulting in the phosphorylation of protein substrates such as PI3K or phospholipase (PL)C. Peptide GPCRs can transactivate numerous RTKs, especially members of the EGFR/HER family resulting in increased phosphorylation of ERK, leading to cellular proliferation or increased phosphorylation of AKT, leading to cellular survival. GRCR antagonists and tyrosine kinase inhibitors are useful agents to prevent RTK transactivation and inhibit proliferation of cancer cells.

Targeting the endothelin axis as a therapeutic strategy for oral cancer metastasis and pain.

Metastasis reduces survival in oral cancer patients and pain is their greatest complaint. We have shown previously that oral cancer metastasis and pain are controlled by the endothelin axis, which is a pathway comprised of the endothelin A and B receptors (ETAR and ETBR). In this study we focus on individual genes of the pathway, demonstrating that the endothelin axis genes are methylated and dysregulated in cancer tissue. Based on these findings in patients, we hypothesize that ETAR and ETBR play dichotomous roles in oral carcinogenesis and pain, such that ETAR activation and silenced ETBR expression result in increased carcinogenesis and pain. We test a treatment strategy that targets the dichotomous functions of the two receptors by inhibiting ETAR with macitentan, an ETAR antagonist approved for treatment of pulmonary hypertension, and re-expressing the ETBR gene with adenovirus transduction, and determine the treatment effect on cancer invasion (i.e., metastasis), proliferation and pain in vitro and in vivo. We demonstrate that combination treatment of macitentan and ETBR gene therapy inhibits invasion, but not proliferation, in cell culture and in a mouse model of tongue cancer. Furthermore, the treatment combination produces an antinociceptive effect through inhibition of endothelin-1 mediated neuronal activation, revealing the analgesic potential of macitentan. Our treatment approach targets a pathway shown to be dysregulated in oral cancer patients, using gene therapy and repurposing an available drug to effectively treat both oral cancer metastasis and pain in a preclinical model.

The EDN2 rs110287192 gene polymorphism is associated with paratuberculosis susceptibility in multibreed cattle population.

Paratuberculosis (pTB), also known as Johne's disease (JD), is a contagious, chronic, and granulomatous inflammatory disease of the intestines of ruminants which is caused by Mycobacterium avium subsp. paratuberculosis (MAP) infection, resulting in billions of dollars in economic losses worldwide. Since, currently, no effective cure is available for MAP infection, it is important to explore the genetic variants that affect the host MAP susceptibility. The aim of this study was to analyze a potential association between EDN2 synonymous gene mutations (rs110287192, rs109651404 and rs136707411), that modifies susceptibility to pTB. EDN2 rs110287192, rs109651404 and rs136707411 mutations were genotyped in 68 infected and 753 healthy animals from East Anatolian Red crossbred, Anatolian Black crossbred and Holstein breed cattle by using Custom TaqMan SNP Genotyping Assays. For pTB status, serum antibody levels S/P ≥ 1.0 were assessed in carriers of the different EDN2 genotypes. EDN2 rs110287192 mutation showed a significant association with bovine pTB (adj. p < 0.05). For rs110287192 locus, the odd ratios for GG and TG genotypes versus TT genotypes were 1.73; (95% CI = 0.34-8.59) and 0.53 (95% CI = 0.12-2.37) respectively, which indicated that proportion of TG heterozygotes were significantly higher in control animals as compared to pTB animals. On the other hand, while rs136707411 mutation showed a suggestive association with pTB status in the examined cattle population (nominal p < 0.05); no association was detected between rs109651404 genotypes and pTB status. Selecting animals against rs110287192-GG genotype may decrease the risk of pTB in cattle of the Bos taurus taurus subspecies.

Hereditary Hearing Impairment with Cutaneous Abnormalities.

Syndromic hereditary hearing impairment (HHI) is a clinically and etiologically diverse condition that has a profound influence on affected individuals and their families. As cutaneous findings are more apparent than hearing-related symptoms to clinicians and, more importantly, to caregivers of affected infants and young individuals, establishing a correlation map of skin manifestations and their underlying genetic causes is key to early identification and diagnosis of syndromic HHI. In this article, we performed a comprehensive PubMed database search on syndromic HHI with cutaneous abnormalities, and reviewed a total of 260 relevant publications. Our in-depth analyses revealed that the cutaneous manifestations associated with HHI could be classified into three categories: pigment, hyperkeratosis/nail, and connective tissue disorders, with each category involving distinct molecular pathogenesis mechanisms. This outline could help clinicians and researchers build a clear atlas regarding the phenotypic features and pathogenetic mechanisms of syndromic HHI with cutaneous abnormalities, and facilitate clinical and molecular diagnoses of these conditions.

Elucidating essential kinases of endothelin signalling by logic modelling of phosphoproteomics data.

Endothelins (EDN) are peptide hormones that activate a GPCR signalling system and contribute to several diseases, including hypertension and cancer. Current knowledge about EDN signalling is fragmentary, and no systems level understanding is available. We investigated phosphoproteomic changes caused by endothelin B receptor (ENDRB) activation in the melanoma cell lines UACC257 and A2058 and built an integrated model of EDNRB signalling from the phosphoproteomics data. More than 5,000 unique phosphopeptides were quantified. EDN induced quantitative changes in more than 800 phosphopeptides, which were all strictly dependent on EDNRB. Activated kinases were identified based on high confidence EDN target sites and validated by Western blot. The data were combined with prior knowledge to construct the first comprehensive logic model of EDN signalling. Among the kinases predicted by the signalling model, AKT, JNK, PKC and AMP could be functionally linked to EDN-induced cell migration. The model contributes to the system-level understanding of the mechanisms underlying the pleiotropic effects of EDN signalling and supports the rational selection of kinase inhibitors for combination treatments with EDN receptor antagonists.

Transition from post-capillary pulmonary hypertension to combined pre- and post-capillary pulmonary hypertension in swine: a key role for endothelin.

KEY POINTS: Passive, isolated post-capillary pulmonary hypertension (PH) secondary to left heart disease may progress to combined pre- and post-capillary or 'active' PH This 'activation' of post-capillary PH significantly increases morbidity and mortality, and is still incompletely understood. In this study, pulmonary vein banding gradually produced post-capillary PH with structural and functional microvascular remodelling in swine. Ten weeks after banding, the pulmonary endothelin pathway was upregulated, likely contributing to pre-capillary aspects in the initially isolated post-capillary PH. Inhibition of the endothelin pathway could potentially stop the progression of early stage post-capillary PH. ABSTRACT: Passive, isolated post-capillary pulmonary hypertension (IpcPH) secondary to left heart disease may progress to combined pre- and post-capillary or 'active' PH (CpcPH) characterized by chronic pulmonary vascular constriction and remodelling. The mechanisms underlying this 'activation' of passive pulmonary hypertension (PH) remain incompletely understood. Here we investigated the role of the vasoconstrictor endothelin-1 (ET) in the progression from IpcPH to CpcPH in a swine model for post-capillary PH. Swine underwent pulmonary vein banding (PVB; n = 7) or sham-surgery (Sham; n = 6) and were chronically instrumented 4 weeks later. Haemodynamics were assessed for 8 weeks, at rest and during exercise, before and after administration of the ET receptor antagonist tezosentan. After sacrifice, the pulmonary vasculature was investigated by histology, RT-qPCR and myograph experiments. Pulmonary arterial pressure and resistance increased significantly over time. mRNA expression of prepro-endothelin-1 and endothelin converting enzyme-1 in the lung was increased, while ETA expression was unchanged and ETB expression was downregulated. This was associated with increased plasma ET levels from week 10 onward and a more pronounced vasodilatation to in vivo administration of tezosentan at rest and during exercise. Myograph experiments showed decreased endothelium-dependent vasodilatation to Substance P and increased vasoconstriction to KCl in PVB swine consistent with increased muscularization observed with histology. Moreover, maximal vasoconstriction to ET was increased whereas ET sensitivity was decreased. In conclusion, PVB swine gradually developed PH with structural and functional vascular remodelling. From week 10 onward, the pulmonary ET pathway was upregulated, likely contributing to pre-capillary activation of the initially isolated post-capillary PH. Inhibition of the ET pathway could thus potentially provide a pharmacotherapeutic target for early stage post-capillary PH.

The endothelin 1 and endothelin receptor A gene polymorphisms increase the risk of developing papillary thyroid cancer.

The endothelin (EDN) axis (EDN1 and EDN1 receptor A, EDNRA) is involved in cellular growth, differentiation, invasiveness, and tumor progression in several cancers. We wanted to examine the possible impact of single nucleotide polymorphisms (SNPs) of EDN1 and EDNRA genes on papillary thyroid cancer (PTC) development and general characteristics of PTC. Study population consist of 113 PTC patients and 185 controls. EDN1 (G5665T, T-1370G) and EDNRA (C TT70G, G-231A) SNPs were investigated by real-time PCR. The GG genotype of EDNRA + 70 SNP was associated with threefold increased PTC risk (p = 0.01), and the combined CG + GG genotype was 2.48 fold higher among PTC patients compared to controls. The variant EDNRA - 231 allele was overrepresented in PTC patients according to controls (p = 0.05). The combined GT + TT genotype of EDN1 5665 SNP was related with late (age after 40 years) PTC onset (p = 0.04), and was more prominent among male patients with PTC according to females (p = 0.03). No significant associations between PTC and - 1370 SNP were found. There were no relationships between laboratory parameters and investigated polymorphisms. The EDNRA + 70 SNP was associated with PTC development. The EDN1 5665 SNP was linked with increased risk for late PTC onset and was more prominent among male patients with PTC.

Human chorionic villous mesenchymal stem/stromal cells protect endothelial cells from injury induced by high level of glucose.

BACKGROUND: Mesenchymal stem/stromal cells derived from chorionic villi of human term placentae (pMSCs) protect human endothelial cells from injury induced by hydrogen peroxide (H2O2). In diabetes, elevated levels of glucose (hyperglycaemia) induce H2O2 production, which causes the endothelial dysfunction that underlies the enhanced immune responses and adverse complications associated with diabetes, which leads to thrombosis and atherosclerosis. In this study, we examined the ability of pMSCs to protect endothelial cell functions from the negative impact of high level of glucose. METHODS: pMSCs isolated from the chorionic villi of human term placentae were cultured with endothelial cells isolated from human umbilical cord veins in the presence of glucose. Endothelial cell functions were then determined. The effect of pMSCs on gene expression in glucose-treated endothelial cells was also determined. RESULTS: pMSCs reversed the effect of glucose on key endothelial cell functions including proliferation, migration, angiogenesis, and permeability. In addition, pMSCs altered the expression of many genes that mediate important endothelial cell functions including survival, apoptosis, adhesion, permeability, and angiogenesis. CONCLUSIONS: This is the first comprehensive study to provide evidence that pMSCs protect endothelial cells from glucose-induced damage. Therefore, pMSCs have potential therapeutic value as a stem cell-based therapy to repair glucose-induced vascular injury and prevent the adverse complications associated with diabetes and cardiovascular disease. However, further studies are necessary to reveal more detailed aspects of the mechanism of action of pMSCs on glucose-induced endothelial damage in vitro and in vivo.

The C9ORF72 Gene, Implicated in Amyotrophic Lateral Sclerosis and Frontotemporal Dementia, Encodes a Protein That Functions in Control of Endothelin and Glutamate Signaling.

A GGGGCC repeat expansion in the C9ORF72 (C9) gene is the most common known cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia. Several mechanisms have been proposed to account for its toxicity, including the possibility that reduced C9 protein levels contribute to disease. To investigate this possibility, we examined the effects of reduced C9 levels in several cell systems. We first showed that C9 knockdown (KD) in U87 glioblastoma cells results in striking morphological changes, including vacuolization and alterations in cell size. Unexpectedly, RNA analysis revealed changes in expression of many genes, including genes involved in endothelin (EDN) signaling and immune system pathways and multiple glutamate cycling genes (e.g., EAAT2), which were verified in several cell models, including astrocytes and brain samples from C9-positive patients. Consistent with deregulation of the glutamate cycling genes, elevated intracellular glutamate was detected in both KD cells and patient astrocytes. Importantly, levels of mRNAs encoding EDN1 and its receptors, known to be elevated in ALS, were sharply increased by C9 KD, likely resulting from an observed activation of NF-κB signaling and/or a possible role of a C9 isoform in gene control.

The Endothelin Type A Receptor as a Potential Therapeutic Target in Preeclampsia.

Preeclampsia (PE) is a disorder of pregnancy typically characterized by new onset hypertension after gestational week 20 and proteinuria. Although PE is one of the leading causes of maternal and perinatal morbidity and death worldwide, the mechanisms of the pathogenesis of the disease remain unclear and treatment options are limited. However, there is increasing evidence to suggest that endothelin-1 (ET-1) plays a critical role in the pathophysiology of PE. Multiple studies report that ET-1 is increased in PE and some studies report a positive correlation between ET-1 and the severity of symptoms. A number of experimental models of PE are also associated with elevated tissue levels of prepro ET-1 mRNA. Moreover, experimental models of PE (placental ischemia, sFlt-1 infusion, Tumor necrosis factor (TNF) -α infusion, and Angiotensin II type 1 receptor autoantibody (AT1-AA) infusion) have proven to be susceptible to Endothelin Type A (ETA) receptor antagonism. While the results are promising, further work is needed to determine whether ET antagonists could provide an effective therapy for the management of preeclampsia.

Endothelin causes transactivation of the EGFR and HER2 in non-small cell lung cancer cells.

Endothelin (ET)-1 is an important peptide in cancer progression stimulating cellular proliferation, tumor angiogenesis and metastasis. ET-1 binds with high affinity to the ETA receptor (R) and ETBR on cancer cells. High levels of tumor ET-1 and ETAR are associated with poor survival of lung cancer patients. Here the effects of ET-1 on epidermal growth factor (EGF)R and HER2 transactivation were investigated using non-small cell lung cancer (NSCLC) cells. ETAR mRNA was present in all 10 NSCLC cell lines examined. Addition of ET-1 to NCI-H838 or H1975 cells increased EGFR, HER2 and ERK tyrosine phosphorylation within 2min. The increase in EGFR and HER2 transactivation caused by ET-1 addition to NSCLC cells was inhibited by lapatinib (EGFR and HER2 tyrosine kinase inhibitor (TKI)), gefitinib (EGFR TKI), ZD4054 or BQ-123 (ETAR antagonist), GM6001 (matrix metalloprotease inhibitor), PP2 (Src inhibitor) or Tiron (superoxide scavenger). ET-1 addition to NSCLC cells increased cytosolic Ca2+ and reactive oxygen species. ET-1 increased NSCLC clonal growth, whereas BQ123, ZD4054, lapatinib or gefitinib inhibited proliferation. The results indicate that ET-1 may regulate NSCLC cellular proliferation in an EGFR- and HER2-dependent manner.

Chronic estrogen exposure affects gene expression in the rostral ventrolateral medulla of young and aging rats: Possible role in hypertension.

BACKGROUND: Chronic exposure to estradiol-17ß (E2) in adult female rats increases mean arterial pressure by stimulating superoxide production in the rostral ventrolateral medulla (RVLM). However the mechanisms behind this phenomenon are unknown. We hypothesized that E2 exposure induces the gene expression of cytokines, chemokines and NADPH oxidase (Nox) in the RVLM that promotes superoxide production and aging would exacerbate this effect. METHODS: Young adult (3-4 month old) and middle-aged (6-8 month old) female Sprague Dawley rats were sham-implanted (YS and MS respectively) or implanted s.c. with slow-release E2 pellets (20 ng of E2/day for 90 days; YE and ME respectively). Blood pressure (BP) was measured during the last 3 weeks of exposure in a separate set of rats. At the end of treatment, the animals were sacrificed and RVLM was isolated from the brainstem. PCR array and Quantitative RT-PCR were performed with the tissue to quantify genes associated with hypertension and superoxide production. Superoxide dismutase (SOD) activity was also measured in the RVLM from a different set of animals. RESULTS: E2 exposure increased mean arterial pressure in both YE and ME animals. Inflammatory genes such as interleukin-1ß, interleukin-6 and monocyte chemoattractant protein-1 were significantly up-regulated in the RVLM of ME treated female rats compared to YS rats, but not in YE rats. Endothelin-1 (ET-1) gene was up-regulated in the RVLM of both YE and ME rats that were exposed to E2. Furthermore, chronic E2 treatment increased the mRNA levels of Nox1 and Nox2 genes in the RVLM of YE but not ME animals. SOD activity was reduced in MA animals, compared to young animals. E2 treatment had no significant effect on SOD activity. CONCLUSION: Chronic E2 exposure stimulates the expression of inflammatory genes in older animals and increases the expression of Nox subunits in the RVLM of younger animals. SOD activity was reduced in older animals. This suggests increased superoxide production in younger animals, but reduced superoxide elimination in older animals. On the other hand, E2 exposure stimulates ET-1 expression in both young and aging animals. These findings suggest that hypertension caused by chronic E2 exposure may involve different molecular mediators in young and aging animals, however ET-1 and superoxide could be common mediators for both age groups.

Therapeutic effects of Lactobacillus casei Qian treatment in activated carbon-induced constipated mice.

In the present study, the therapeutic effects of Lactobacillus casei Qian (LC-Qian), the key microorganism in Tibetan yak yoghurt, on activated carbon-induced constipation were determined in vivo. ICR mice were treated with LC-Qian for nine days by oral administration. The body weight, defecation status, gastrointestinal transit and defecation time of mice were assessed, and the serum levels of motilin (MTL), gastrin (Gas), endothelin (ET), somatostatin (SS), acetylcholinesterase (AChE), substance P (SP) and vasoactive intestinal peptide (VIP) were further evaluated. Bisacodyl was used as the positive control. The time until the first black stool defecation following carbon intake of the normal, control, 100 mg/kg bisacodyl-treated, Lactobacillus bulgaricus (LB)-treated, LC-Qian (L)-and LC-Qian (H)-treated mice was 93, 231, 121, 194, 172 and 157 min, respectively. Following treatment with LC-Qian, the gastrointestinal transit was increased to 52.4% [LC-Qian (L)] and 65.8% [LC-Qian (H)], while that in the group treated with the common lactic acid bacteria of LB was 40.3%. The MTL, Gas, ET, AChE, SP and VIP serum levels were significantly increased and levels of SS were reduced in mice following LC-Qian treatment compared with those in the control mice (P<0.05). Reverse transcription quantitative polymerase chain reaction indicated that LC-Qian raised the c-Kit, GDNF as well as SCF mRNA expression levels and reduced the TRPV1 and NOS expression levels in tissue of the small intestine in mice. These results suggested that lactic acid bacteria prevent constipation in mice, among which LC-Qian was the most effective.

Pathogenic pathways are activated in each major cell type of the glomerulus in the Cd2ap mutant mouse model of focal segmental glomerulosclerosis.

BACKGROUND: Mutations in several genes expressed in podocytes, including Cd2ap, have been associated with focal segmental glomerulosclerosis in humans. Mutant mouse models provide an opportunity to better understand the molecular pathology that drives these diseases. METHODS: In this report we use a battery of transgenic-GFP mice to facilitate the purification of all three major cell types of the glomerulus from Cd2ap mutant mice. Both microarrays and RNA-seq were used to characterize the gene expression profiles of the podocytes, mesangial cells and endothelial cells, providing a global dual platform cross-validating dataset. RESULTS: The mesangial cells showed increased expression of profibrotic factors, including thrombospondin, Tgfb2 and Tgfb3, as well as the angiogenesis factor Vegf. They also showed upregulation of protective genes, including Aldh1a2, involved in retinoic acid synthesis and Decorin, a Tgfb antagonist. Of interest, the mesangial cells also showed significant expression of Wt1, which has generally been considered podocyte specific. The Cd2ap mutant podocytes showed upregulation of proteases as well as genes involved in muscle and vasculature development and showed a very strong gene expression signature indicating programmed cell death. Endothelial cells showed increased expression of the leukocyte adhesion associated factors Vcam1 and Sele, as well as Midkine (promoting angiogenesis), endothelin and many genes responsive to cytokines and interferons. CONCLUSIONS: This study provides a comprehensive analysis of the changing properties of the three cell types of the glomerulus in Cd2ap mutants, identifying activated and repressed pathways and responsible genes, thereby delivering a deeper molecular understanding of this genetic disease.

Privileged frameworks from snake venom.

Venom as a form of chemical prey capture is a key innovation that has underpinned the explosive radiation of the advanced snakes (Caenophidia). Small venom proteins are often rich in disulfide bonds thus facilitating stable molecular scaffolds that present key functional residues on the protein surface. New toxin types are initially developed through the venom gland over-expression of normal body proteins, their subsequent gene duplication and diversification that leads to neofunctionalisation as random mutations modify their structure and function. This process has led to preferentially selected (privileged) cysteine-rich scaffolds that enable the snake to build arrays of toxins many of which may lead to therapeutic products and research tools. This review focuses on cysteine-rich small proteins and peptides found in snake venoms spanning natriuretic peptides to phospholipase enzymes, while highlighting their three-dimensional structures and biological functions as well as their potential as therapeutic agents or research tools.

Endothelin@25 - new agonists, antagonists, inhibitors and emerging research frontiers: IUPHAR Review 12.

Since the discovery of endothelin (ET)-1 in 1988, the main components of the signalling pathway have become established, comprising three structurally similar endogenous 21-amino acid peptides, ET-1, ET-2 and ET-3, that activate two GPCRs, ETA and ETB . Our aim in this review is to highlight the recent progress in ET research. The ET-like domain peptide, corresponding to prepro-ET-193-166 , has been proposed to be co-synthesized and released with ET-1, to modulate the actions of the peptide. ET-1 remains the most potent vasoconstrictor in the human cardiovascular system with a particularly long-lasting action. To date, the major therapeutic strategy to block the unwanted actions of ET in disease, principally in pulmonary arterial hypertension, has been to use antagonists that are selective for the ETA receptor (ambrisentan) or that block both receptor subtypes (bosentan). Macitentan represents the next generation of antagonists, being more potent than bosentan, with longer receptor occupancy and it is converted to an active metabolite; properties contributing to greater pharmacodynamic and pharmacokinetic efficacy. A second strategy is now being more widely tested in clinical trials and uses combined inhibitors of ET-converting enzyme and neutral endopeptidase such as SLV306 (daglutril). A third strategy based on activating the ETB receptor, has led to the renaissance of the modified peptide agonist IRL1620 as a clinical candidate in delivering anti-tumour drugs and as a pharmacological tool to investigate experimental pathophysiological conditions. Finally, we discuss biased signalling, epigenetic regulation and targeting with monoclonal antibodies as prospective new areas for ET research.

Endothelin system mRNA variation in the heart of Zucker rats: evaluation of a possible balance with natriuretic peptides.

BACKGROUND AND AIMS: The deregulation of neurohormonal systems, including the natriuretic peptide (NP) and endothelin (ET) systems, may increase the possibility of developing obesity-related risk. The aim of our paper was to evaluate ET system mRNA variation in heart of the Zucker rat model together with the simultaneous evaluation of the NP system transcriptomic profile. In order to analyze the link between the ET-1 system and the inflammatory process, the cardiac expression of interleukin (IL)-6 and tumor necrosis factor (TNF)-α was also measured. METHODS AND RESULTS: Zucker rats of 11-13 weeks were subdivided into obese rats (O, n = 20) and controls (CO, n = 20): half of them were studied under fasting conditions (CO(fc)-O(fc)) and the remainder after the induction of acute hyperglycemia (CO(AH)-O(AH)). Cardiac mRNA expression of TNF-α, IL-6, and NP/ET-1 systems was evaluated by Real-Time polymerase chain reaction. No significant difference for pre-proET-1, ET-A, and ET-B mRNA expression was detected between O and CO, whereas significantly lower mRNA levels of the ECE-1 were observed in O (p = 0.02). Regarding NPs, only BNP mRNA expression decreased significantly in O with respect to CO (p = 0.01). A down-regulation of NPR-B and NPR-C and an up-regulation of NPR-A were observed in O. No significant difference for IL-6 and TNF-α mRNA was revealed. Subdividing into fasting and hyperglycemic rats, many of the genes studied maintained their mRNA expression pattern almost unchanged. CONCLUSIONS: The modulation of ET-1/NP systems in obesity could be a useful starting point for future studies aimed at identifying new therapeutic strategies for the treatment of cardiometabolic syndrome.

Role of the endothelin axis in astrocyte- and endothelial cell-mediated chemoprotection of cancer cells.

BACKGROUND: Recent evidence suggests that astrocytes protect cancer cells from chemotherapy by stimulating upregulation of anti-apoptotic genes in those cells. We investigated the possibility that activation of the endothelin axis orchestrates survival gene expression and chemoprotection in MDA-MB-231 breast cancer cells and H226 lung cancer cells. METHODS: Cancer cells, murine astrocytes, and murine fibroblasts were grown in isolation, and expression of endothelin (ET) peptides and ET receptors (ETAR and ETBR) compared with expression on cancer cells and astrocytes (or cancer cells and fibroblasts) that were co-incubated for 48 hours. Type-specific endothelin receptor antagonists were used to evaluate the contribution of ETAR and ETBR to astrocyte-induced activation of the protein kinase B (AKT)/mitogen-activated protein kinase (MAPK) signal transduction pathways, anti-apoptotic gene expression, and chemoprotection of cancer cells. We also investigated the chemoprotective potential of brain endothelial cells and microglial cells. RESULTS: Gap junction signaling between MDA-MB-231 cancer cells and astrocytes stimulates upregulation of interleukin 6 (IL-6) and IL-8 expression in cancer cells, which increases ET-1 production from astrocytes and ET receptor expression on cancer cells. ET-1 signals for activation of AKT/MAPK and upregulation of survival proteins that protect cancer cells from taxol. Brain endothelial cell-mediated chemoprotection of cancer cells also involves endothelin signaling. Dual antagonism of ETAR and ETBR is required to abolish astrocyte- and endothelial cell-mediated chemoprotection. CONCLUSIONS: Bidirectional signaling between astrocytes and cancer cells involves upregulation and activation of the endothelin axis, which protects cancer cells from cytotoxicity induced by chemotherapeutic drugs.