Irreversible and sustained upregulation of endothelin axis during oncogene-associated pancreatic inflammation and cancer

Endothelin-1 (ET-1) and its two receptors, endothelin receptor A (ETAR) and endothelin receptor B (ETBR) exhibit deregulated overexprerssion in pancreatic ductal adenocarcinoma (PDAC) and pancreatitis. We examined the expression pattern of endothelin (ET) axis components in the murine models of chronic and acute inflammation in the presence or absence of oncogenic K-ras. While the expression of endothelin converting enzyme-1 (ECE-1), ET-1, ETAR and ETBR in the normal pancreas is restricted predominantly to the islet cells, progressive increase of ET receptors in ductal cells and stromal compartment is observed in the KC model (Pdx-1 Cre; K-rasG12D) of PDAC. In the murine pancreas harboring K-rasG12D mutation (KC mice), following acute inflammation induced by cerulein, increased ETAR and ETBR expression is observed in the amylase and CK19 double positive cells that represent cells undergoing pancreatic acinar to ductal metaplasia (ADM). As compared to the wild type (WT) mice, cerulein treatment in KC mice resulted in significantly higher levels of ECE-1, ET-1, ETAR and ETBR, transcripts in the pancreas. Similarly, in response to cigarette smoke-induced chronic inflammation, the expression of ET axis components is significantly upregulated in the pancreas of KC mice as compared to the WT mice. In addition to the expression in the precursor pancreatic intraepithelial neoplasm (PanIN lesions) in cigarette smoke-exposure model and metaplastic ducts in cerulein-treatment model, ETAR and ETBR expression is also observed in infiltrating F4/80 positive macrophages and α-SMA positive fibroblasts and high co-localization was seen in the presence of oncogenic K-ras. In conclusion, both chronic and acute pancreatic inflammation in the presence of oncogenic K-ras contribute to sustained upregulation of ET axis components in the ductal and stromal cells suggesting a potential role of ET axis in the initiation and progression of PDAC.

ECE2 is a prognostic biomarker associated with m6A modification and involved in immune infiltration of lung adenocarcinoma

BACKGROUND

The targeted therapy for lung cancer relies on prognostic genes and requires further research. No research has been conducted to determine the effect of endothelin-converting enzyme 2 (ECE2) in lung cancer.

METHODS

We analyzed the expression of ECE2 in lung adenocarcinoma (LUAD) and normal adjacent tissues and its relationship with clinicopathological characteristics from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus database (GEO). Immunohistochemical staining was used to further validate the findings. GO/KEGG enrichment analysis and gene set enrichment analysis (GSEA) of ECE2 co-expression were performed using R software. Data from TIMER, the GEPIA database, and TCGA were analyzed to determine the relationship between ECE2 expression and LUAD immune infiltration. To investigate the relationship between ECE2 expression levels and LUAD m6A modification, TCGA data and GEO data were analyzed.

RESULTS

ECE2 is highly expressed in various cancers including LUAD. ECE2 showed high accuracy in distinguishing tumor and normal sample results. The expression level of ECE2 in LUAD was significantly correlated with tumor stage and prognosis. GO/KEGG enrichment analysis showed that ECE2 was closely related to mitochondrial gene expression, ATPase activity and cell cycle. GSEA analysis showed that ECE2-related differential gene enrichment pathways were related to mitotic cell cycle, MYC pathway, PLK1 pathway, DNA methylation pathway, HIF1A pathway and Oxidative stress-induced cellular senescence. Analysis of the TIMER, GEPIA database, and TCGA datasets showed that ECE2 expression levels were significantly negatively correlated with B cells, CD4+ cells, M2 macrophages, neutrophils, and dendritic cells. TCGA and GEO datasets showed that ECE2 was significantly associated with m6A modification-related genes HNRNPC, IGF2BP1, IGF2BP3 and RBM1.

CONCLUSION

ECE2 is associated with m6A modification and immune infiltration and is a prognostic biomarker in LUAD.

Cisplatin-resistance and aggressiveness are enhanced by a highly stable endothelin-converting enzyme-1c in lung cancer cells

BACKGROUND

Lung cancer constitutes the leading cause of cancer mortality. High levels of endothelin-1 (ET-1), its cognate receptor ETAR and its activating enzyme, the endothelin-converting enzyme-1 (ECE-1), have been reported in several cancer types, including lung cancer. ECE-1 comprises four isoforms, which only differ in their cytoplasmic N-terminus. Protein kinase CK2 phosphorylates the N-terminus of isoform ECE-1c, increasing its stability and leading to enhanced invasiveness in glioblastoma and colorectal cancer cells, which is believed to be mediated by the amino acid residue Lys-6, a conserved putative ubiquitination site neighboring the CK2-phosphorylated residues Ser-18 and Ser-20. Whether Lys-6 is linked to the acquisition of a cancer stem cell (CSC)-like phenotype and aggressiveness in human non-small cell lung cancer (NSCLC) cells has not been studied.

METHODS

In order to establish the role of Lys-6 in the stability of ECE-1c and its involvement in lung cancer aggressiveness, we mutated this residue to a non-ubiquitinable arginine and constitutively expressed the wild-type (ECE-1cWT) and mutant (ECE-1cK6R) proteins in A549 and H1299 human NSCLC cells by lentiviral transduction. We determined the protein stability of these clones alone or in the presence of the CK2 inhibitor silmitasertib, compared to ECE-1cWT and mock-transduced cells. In addition, the concentration of secreted ET-1 in the growth media was determined by ELISA. Expression of stemness genes were determined by Western blot and RT-qPCR. Chemoresistance to cisplatin was studied by MTS viability assay. Migration and invasion were measured through transwell and Matrigel assays, respectively, and the side-population was determined using flow cytometry.

RESULTS

ECE-1cK6R displayed higher stability in NSCLC cells compared to ECE-1cWT-expressing cells, but ET-1 secreted levels showed no difference up to 48 h. Most importantly, ECE-1cK6R promoted expression of the stemness genes c-Myc, Sox-2, Oct-4, CD44 and CD133, which enhance cellular self-renewal capability. Also, the ECE-1cK6R-expressing cells showed higher cisplatin chemoresistance, correlating with an augmented side-population abundance due to the increased expression of the ABCG2 efflux pump. Finally, the ECE-1cK6R-expressing cells showed enhanced invasiveness, which correlated with the regulated expression of known EMT markers.

CONCLUSIONS

Our findings suggest an important role of ECE-1c in lung cancer. ECE-1c is key in a non-canonical ET-1-independent mechanism which triggers a CSC-like phenotype, leading to enhanced lung cancer aggressiveness. Underlying this mechanism, ECE-1c is stabilized upon phosphorylation by CK2, which is upregulated in many cancers. Thus, phospho-ECE-1c may be considered as a novel prognostic biomarker of recurrence, as well as the CK2 inhibitor silmitasertib as a potential therapy for lung cancer patients.

Comprehensive analysis of the endothelin system in the kidneys of mice, rats, and humans

The intrarenal endothelin (ET) system is an established moderator of kidney physiology and mechanistic contributor to the pathophysiology and progression of chronic kidney disease in humans and rodents. The aim of the present study was to characterize ET system by combining single cell RNA sequencing (scRNA-seq) data with immunolocalization in human and rodent kidneys of both sexes. Using publicly available scRNA-seq data, we assessed sex and kidney disease status (human), age and sex (rats), and diurnal expression (mice) on the kidney ET system expression. In normal human biopsies of both sexes and in rodent kidney samples, the endothelin-converting enzyme-1 (ECE1) and ET-1 were prominent in the glomeruli and endothelium. These data agreed with the scRNA-seq data from these three species, with ECE1/Ece1 mRNA enriched in the endothelium. However, the EDN1/Edn1 gene (encodes ET-1) was rarely detected, even though it was immunolocalized within the kidneys, and plasma and urinary ET-1 excretion are easily measured. Within each species, there were some sex-specific differences. For example, in kidney biopsies from living donors, men had a greater glomerular endothelial cell endothelin receptor B (Ednrb) compared with women. In mice, females had greater kidney endothelial cell Ednrb than male mice. As commercially available antibodies did not work in all species, and RNA expression did not always correlate with protein levels, multiple approaches should be considered to maintain required rigor and reproducibility of the pre- and clinical studies evaluating the intrarenal ET system.

A non-canonical role of endothelin converting enzyme 1 (ECE1) in promoting lung cancer development via directly targeting protein kinase B (AKT)

BACKGROUND

Lung cancer is the second most common malignancy in the world, and lung adenocarcinoma (LUAD) in particular is the leading cause of cancer death worldwide. Endothelin converting enzyme 1 (ECE1) is a membrane-bound metalloprotease involved in endothelin-1 (ET-1) processing and regulates vasoconstriction. However, very few studies have reported the involvement of ECE1 in regulating tumor cell proliferation, and the mechanism remains poorly understood. Therefore, we aimed to determine the role of ECE1 in lung cancer development.

METHODS

The Cancer Genome Atlas database and Kaplan-Meier plotter were used to assess the association between ECE1 and lung cancer. The expression of ECE1 was detected using immunohistochemistry staining and western blotting. A variety of in vitro assays were performed to evaluate the effects of ECE1 on the colony formation, proliferation, migration and invasion using ECE1 knockdown lung cancer cells. The gene expression profiles regulated by ECE1 were investigated by RNA sequencing. An immunoprecipitation assay and immunofluorescence assay were used to evaluate the mechanism underlying the regulatory effect of ECE1 on protein kinase B (AKT). The effect of ECE1 on tumor development was assessed by xenografted lung cancer cells in either C57BL/6 mice or nude mice.

RESULTS

ECE1 was upregulated in LUAD and correlated with the poor prognosis of patients with LUAD. Functional studies showed that knockdown of ECE1 retarded the progression of tumors formed by lung cancer cells at least partly by inhibiting tumor cell proliferation. Moreover, ECE1 accelerated tumor cell proliferation through promoting AKT activation dispensable of its canonical target ET-1. Mechanically, ECE1 interacted with the pleckstrin homology (PH) domain of AKT and facilitated its translocation to the plasma membrane for activation. Furthermore, the inhibition of AKT activity counteracted the lung cancer cell growth inhibition observed both in vitro and in xenografts caused by ECE1 suppression.

CONCLUSIONS

The present study reveals a non-canonical function of ECE1 in regulating AKT activation and cell proliferation, which provides the basis for the development of a novel strategy for the intervention of cancer including LUAD by abrogating ECE1-AKT signaling.

Mutation analysis of the ECE1 gene in late-onset Alzheimer's disease

We recently identified a rare coding mutation (R186C) in the ECE2 gene in a late-onset AD (LOAD) family, and demonstrated ECE2 is a risk gene for AD development. ECE1 is a homologous enzyme that shares catalytic activity with ECE2. Although ECE1 has been regarded as a potential candidate gene for AD, few studies have investigated the role of ECE1 variants in patients with AD. In this study, we aimed to investigate rare variants in ECE1 in a cohort of 610 patients with LOAD (age of onset ≥65 years). The summary data of ECE1 variants from ChinaMAP database were used as controls (n = 10,588). We found four rare variants (p.R50W, p.A166=, p.R650Q, and p.P751=) in the patients with sporadic LOAD, while we identified a large number of controls carrying rare variants in ECE1. Moreover, there was no significant association between LOAD and non-synonymous rare damaging variants at the gene level. Our results suggest rare coding variants of ECE1 might not play an important role in AD risk in the Chinese population.

Unveiling the peptidases of parasites from the office chair - The endothelin-converting enzyme case study

The emergence of high-throughput methodologies such as next-generation sequencing and proteomics has necessitated significant advancements in biological databases and bioinformatic tools, therefore reshaping the landscape of research into parasitic peptidases. In this review we outline the development of these resources along the -omics technologies and their transformative impact on the field. Apart from extensive summary of general and specific databases and tools, we provide a general pipeline on how to use these resources effectively to identify candidate peptidases from these large datasets and how to gain as much information about them as possible without leaving the office chair. This pipeline is then applied in an illustrative case study on the endothelin-converting enzyme 1 homologue from Schistosoma mansoni and attempts to highlight the contemporary capabilities of bioinformatics. The case study demonstrate how such approach can aid to hypothesize enzyme functions and interactions through computational analysis alone effectively and emphasizes how such virtual investigations can guide and optimize subsequent wet lab experiments therefore potentially saving precious time and resources. Finally, by showing what can be achieved without traditional wet laboratory methods, this review provides a compelling narrative on the use of bioinformatics to bridge the gap between big data and practical research applications, highlighting the key role of these technologies in furthering our understanding of parasitic diseases.

Cancer Stem Cell and Aggressiveness Traits Are Promoted by Stable Endothelin-Converting Enzyme-1c in Glioblastoma Cells

Glioblastoma (GBM) is the most common and aggressive type of brain tumor due to its elevated recurrence following treatments. This is mainly mediated by a subpopulation of cells with stemness traits termed glioblastoma stem-like cells (GSCs), which are extremely resistant to anti-neoplastic drugs. Thus, an advancement in the understanding of the molecular processes underlying GSC occurrence should contribute significantly towards progress in reducing aggressiveness. High levels of endothelin-converting enzyme-1 (ECE1), key for endothelin-1 (ET-1) peptide activation, have been linked to the malignant progression of GBM. There are four known isoforms of ECE1 that activate ET-1, which only differ in their cytoplasmic N-terminal sequences. Isoform ECE1c is phosphorylated at Ser-18 and Ser-20 by protein kinase CK2, which increases its stability and hence promotes aggressiveness traits in colon cancer cells. In order to study whether ECE1c exerts a malignant effect in GBM, we designed an ECE1c mutant by switching a putative ubiquitination lysine proximal to the phospho-serines Lys-6-to-Arg (i.e., K6R). This ECE1cK6R mutant was stably expressed in U87MG, T98G, and U251 GBM cells, and their behavior was compared to either mock or wild-type ECE1c-expressing clone cells. ECE1cK6R behaved as a highly stable protein in all cell lines, and its expression promoted self-renewal and the enrichment of a stem-like population characterized by enhanced neurospheroid formation, as well as increased expression of stem-like surface markers. These ECE1cK6R-derived GSC-like cells also displayed enhanced resistance to the GBM-related chemotherapy drugs temozolomide and gemcitabine and increased expression of the ABCG2 efflux pump. In addition, ECE1cK6R cells displayed enhanced metastasis-associated traits, such as the modulation of adhesion and the enhancement of cell migration and invasion. In conclusion, the acquisition of a GSC-like phenotype, together with heightened chemoresistance and invasiveness traits, allows us to suggest phospho-ECE1c as a novel marker for poor prognosis as well as a potential therapeutic target for GBM.

Endothelin-converting Enzyme-1b Genetic Variants Increase the Risk of Coronary Artery Ectasia

Coronary artery ectasia (CAE), defined as a 1.5-fold or greater enlargement of a coronary artery segment compared to the adjacent normal coronary artery, is frequently associated with atherosclerotic coronary artery disease (CAD). Membrane-bound endothelin converting enzyme-1 (ECE-1) is involved in the maturation process of the most potent vasoconstrictor ET-1. Polymorphisms in the endothelin (ET) gene family have been shown associated with the development of atherosclerosis. This study aims to investigate the effects of rs213045 and rs2038089 polymorphisms in the ECE-1 gene which have been previously shown to be associated with atherosclerosis and hypertension (HT), in CAE patients. Ninety-six CAE and 175 patients with normal coronary arteries were included in the study. ECE-1b gene variations rs213045 and rs2038089 were determined by real-time PCR. The frequencies of rs213045 C > A (C338A) CC genotype (60.4% vs. 35.4%, p < 0.001) and rs2038089 T > C T allele (64.58% vs. 35.42%, p = 0.017) were higher in the CAE group compared to the control group. The multivariate regression analysis showed that the ECE-1b rs213045 CC genotype (p = 0.001), rs2038089 T allele (p = 0.017), and hypercholesterolemia (HC) (p = 0.001) are risk factors for CAE. Moreover, in nondiabetic individuals of the CAE and control groups, it was observed that the rs213045 CC genotype (p < 0.001), and rs2038089 T allele (p = 0.003) were a risk factor for CAE, but this relationship was not found in the diabetic subgroups of the study groups (p > 0.05). These results show that ECE-1b polymorphisms may be associated with the risk of CAE and this relationship may change according to the presence of type II diabetes.

Exome sequencing identifies novel genetic variants associated with varicose veins

BACKGROUND

Varicose veins (VV) are one of the common human diseases, but the role of genetics in its development is not fully understood.

METHODS

We conducted an exome-wide association study of VV using whole-exome sequencing data from the UK Biobank, and focused on common and rare variants using single-variant association analysis and gene-level collapsing analysis.

FINDINGS

A total of 13,823,269 autosomal genetic variants were obtained after quality control. We identified 36 VV-related independent common variants mapping to 34 genes by single-variant analysis and three rare variant genes (PIEZO1, ECE1, FBLN7) by collapsing analysis, and most associations between genes and VV were replicated in FinnGen. PIEZO1 was the closest gene associated with VV (P = 5.05 × 10-31), and it was found to reach exome-wide significance in both single-variant and collapsing analyses. Two novel rare variant genes (ECE1 and METTL21A) associated with VV were identified, of which METTL21A was associated only with females. The pleiotropic effects of VV-related genes suggested that body size, inflammation, and pulmonary function are strongly associated with the development of VV.

CONCLUSIONS

Our findings highlight the importance of causal genes for VV and provide new directions for treatment.

Brachial Plexus Root Avulsion Injury-Induced Endothelin-Converting Enzyme-Like 1 Overexpression Is Associated with Injured Motor Neurons Survival

Brachial plexus root avulsion (BPRA) injury arises from challenging delivery during childbirth, sports-related incidents, or car accidents, leading to extensive loss of motor neurons (MNs) and subsequent paralysis, including both motor and sensory impairment. Surgical nerve re-implantation cannot effectively restore motor function, and the survival of injured MNs is vital for axon regeneration and re-innervating the target muscles. Therefore, identifying novel molecular targets to improve injured MNs survival is of great significance in the treatment of BPRA injuries. Endothelin-converting enzyme-like 1 (ECEL1), a membrane-bound metallopeptidase, was initially identified as a molecule associated with nerve injuries. Damaged neurons exhibit a significant increase in the expression of ECEL1 following various types of nerve injuries, such as optic nerve injury and sciatic nerve injury. This study aimed to investigate the relationship between ECEL1 overexpression and the survival of injured MNs following BPRA injury. Our results observed a significant elevation in ECEL1 expression in injured MNs and positively correlated with MNs survival following BPRA injury. The transcription of ECEL1 is regulated by the transcription factors c-Jun and ATF3 in the context of BPRA injury, which is consistent with previous other nerve injuries study. In addition, the expression of TrkA gradually decreases in ECEL1-positive MNs and ECEL1 possibly preserves the activity of downstream AKT-GSK3β pathway of TrkA in injured MNs. In conclusion, our results introduce a promising therapeutic molecular target to assist re-implantation surgery for the treatment of BPRA injury.

Identification of ECE2 signaling in promoting non-small lung cancer progression through ET1/YAP1/MAGEA3 axis

Non-small cell lung cancer (NSCLC) is a major cause of cancer-related mortality worldwide with high heterogeneity. However, the molecular basis for NSCLC development remains poorly understood. In this study, we analyzed endothelin converting enzyme 2 (ECE2) expression in NSCLC using transcriptome data from 59 normal and 515 NSCLC tissues obtained from The cancer genome atlas (TCGA) database. Additionally, we investigated the role of ECE2 in metastasis using 30 clinical NSCLC specimens. In vitro cell proliferation and migration assays were conducted using CCK8 and Transwell assays in NSCLC cells overexpressing ECE2. We employed Western blotting and immunostaining to assess activation of the endothelin-1 (ET1)/YAP1/MAGEA3 pathway. Furthermore, in vivo studies using subcutaneous xenograft mouse models with vector and ECE2-overexpressing A549 cells evaluated the anticancer effects. Our findings revealed elevated ECE2 expression in NSCLC tissues associated with poor prognosis. Moreover, overexpression of ECE2 enhanced both the proliferative and metastatic potential of NSCLC cells. Mechanistically, ECE2 promoted the production of ET1 in NSCLC cells. Subsequently, increased ET1 levels activated the YAP1/MAGEA3 pathway, thereby facilitating tumor progression. Our study uncovered the oncogenic role of ECE2 in promoting NSCLC growth through the ET1/YAP1/MAGEA3 pathway. Inhibiting ET1 signaling markedly enhanced the anticancer effectiveness of paclitaxel (PTX), providing a promising approach for managing NSCLC.