HMGA1 sensitizes esophageal squamous cell carcinoma to mTOR inhibitors through the ETS1-FKBP12 axis.

Esophageal carcinoma is amongst the prevalent malignancies worldwide, characterized by unclear molecular classifications and varying clinical outcomes. The PI3K/AKT/mTOR signaling, one of the frequently perturbed dysregulated pathways in human malignancies, has instigated the development of various inhibitory agents targeting this pathway, but many ESCC patients exhibit intrinsic or adaptive resistance to these inhibitors. Here, we aim to explore the reasons for the insensitivity of ESCC patients to mTOR inhibitors. We assessed the sensitivity to rapamycin in various ESCC cell lines by determining their respective IC50 values and found that cells with a low level of HMGA1 were more tolerant to rapamycin. Subsequent experiments have supported this finding. Through a transcriptome sequencing, we identified a crucial downstream effector of HMGA1, FKBP12, and found that FKBP12 was necessary for HMGA1-induced cell sensitivity to rapamycin. HMGA1 interacted with ETS1, and facilitated the transcription of FKBP12. Finally, we validated this regulatory axis in in vivo experiments, where HMGA1 deficiency in transplanted tumors rendered them resistance to rapamycin. Therefore, we speculate that mTOR inhibitor therapy for individuals exhibiting a reduced level of HMGA1 or FKBP12 may not work. Conversely, individuals exhibiting an elevated level of HMGA1 or FKBP12 are more suitable candidates for mTOR inhibitor treatment.

Proteomics Analysis of the Polyomavirus DNA Replication Initiation Complex Reveals Novel Functional Phosphorylated Residues and Associated Proteins.

Polyomavirus (PyV) Large T-antigen (LT) is the major viral regulatory protein that targets numerous cellular pathways for cellular transformation and viral replication. LT directly recruits the cellular replication factors involved in initiation of viral DNA replication through mutual interactions between LT, DNA polymerase alpha-primase (Polprim), and single-stranded DNA binding complex, (RPA). Activities and interactions of these complexes are known to be modulated by post-translational modifications; however, high-sensitivity proteomic analyses of the PTMs and proteins associated have been lacking. High-resolution liquid chromatography tandem mass spectrometry (LC-MS/MS) of the immunoprecipitated factors (IPMS) identified 479 novel phosphorylated amino acid residues (PAARs) on the three factors; the function of one has been validated. IPMS revealed 374, 453, and 183 novel proteins associated with the three, respectively. A significant transcription-related process network identified by Gene Ontology (GO) enrichment analysis was unique to LT. Although unidentified by IPMS, the ETS protooncogene 1, transcription factor (ETS1) was significantly overconnected to our dataset indicating its involvement in PyV processes. This result was validated by demonstrating that ETS1 coimmunoprecipitates with LT. Identification of a novel PAAR that regulates PyV replication and LT's association with the protooncogenic Ets1 transcription factor demonstrates the value of these results for studies in PyV biology.

Cellular senescence-Related genes define the immune microenvironment and molecular characteristics in severe asthma patients.

Recent studies have shown that cellular senescence is involved in the pathogenesis of severe asthma (SA). The objective of this study was to investigate the role of cellular senescence-related genes (CSGs) in the pathogenesis of SA. Here, 54 differentially expressed CSGs were identified in SA patients compared to healthy control individuals. Among the 54 differentially expressed CSGs, 3 CSGs (ETS2, ETS1 and AURKA) were screened using the LASSO regression analysis and logistic regression analysis to establish the CSG-based prediction model to predict severe asthma. Moreover, we found that the protein expression levels of ETS2, ETS1 and AURKA were increased in the severe asthma mouse model. Then, two distinct senescence subtypes of SA with distinct immune microenvironments and molecular biological characteristics were identified. Cluster 1 was characterized by increased infiltration of immature dendritic cells, regulatory T cells, and other cells. Cluster 2 was characterized by increased infiltration levels of eosinophils, neutrophils, and other cells. The molecular biological characteristics of Cluster 1 included aerobic respiration and oxidative phosphorylation, whereas the molecular biological characteristics of Cluster 2 included activation of the immune response and immune receptor activity. Then, we established an Random Forest model to predict the senescence subtypes of SA to guide treatment. Finally, potential drugs were searched for each senescence subgroup of SA patients via the Connectivity Map database. A peroxisome proliferator-activated receptor agonist may be a potential therapeutic drug for patients in Cluster 1, whereas a tachykinin antagonist may be a potential therapeutic drug for patients in Cluster 2. In summary, CSGs are likely involved in the pathogenesis of SA, which may lead to new therapeutic options for SA patients.

IGF2BP2-m6A-circMMP9 axis recruits ETS1 to promote TRIM59 transcription in laryngeal squamous cell carcinoma.

Laryngeal squamous cell carcinoma (LSCC) is a common malignancy of the head and neck. Recently, circular RNA (circRNA) has been studied extensively in multisystem diseases. However, there are few research on biological functions and molecular mechanisms of circRNAs in LSCC. CircRNA array was used to detect the differentially expressed circRNAs. Kaplan-Meier and cox regression analysis were used to identify survival based on circMMP9. The qRT-PCR, RNase R treatment, sanger sequencing and in situ hybridization were used to verify circMMP9 expression, characteristics and localization in LSCC tissues and cells. Functionally, colony formation, MTS, transwell and in vivo assays were proceeded to detect the biological function of circMMP9 in LSCC progression. The RNA-seq was conducted to identify the molecular targets of circMMP9. Mechanically, MeRIP, RNA Immunoprecipitation (RIP), RNA pulldown, Chromatin immunoprecipitation (ChIP) and dual-luciferase reporter assays were carried on to verify the regulatory mechanism of circMMP9. CircMMP9 was discovered upregulated in LSCC tissues and cells, and high level of circMMP9 was associated with poor prognosis, low degree of pathological grading, high TNM stage and lymph node metastasis of LSCC. CircMMP9 knockdown prevented LSCC progression both in vitro and in vivo, whereas, circMMP9 overexpression had the opposite effect. CircMMP9 was stabilized by IGF2BP2 in m6A-dependent manner. TRIM59 was identified as downstream target of circMMP9. CircMMP9 recruited ETS1 to stimulate TRIM59 transcription. Moreover, TRIM59 accelerated LSCC progression via activating the PI3K/AKT signal pathway. Our findings offered a unique regulatory mechanism for circMMP9 in LSCC, as well as a novel proof that circMMP9 may be utilize as a diagnostic marker and therapeutic target for LSCC patients.

Allele-specific effect of various dietary fatty acids and ETS1 transcription factor on SCD1 expression.

Overnutrition and genetic predisposition are major risk factors for various metabolic disorders. Stearoyl-CoA desaturase-1 (SCD1) plays a key role in these conditions by synthesizing unsaturated fatty acids (FAs), thereby promoting fat storage and alleviating lipotoxicity. Expression of SCD1 is influenced by various saturated and cis-unsaturated FAs, but the possible role of dietary trans FAs (TFAs) and SCD1 promoter polymorphisms in its regulations has not been addressed. Therefore, we aimed to investigate the impact of the two main TFAs, vaccenate and elaidate, and four common promoter polymorphisms (rs1054411, rs670213, rs2275657, rs2275656) on SCD1 expression in HEK293T and HepG2 cell cultures using luciferase reporter assay, qPCR and immunoblotting. We found that SCD1 protein and mRNA levels as well as SCD1 promoter activity are markedly elevated by elaidate, but not altered by vaccenate. The promoter polymorphisms did not affect the basal transcriptional activity of SCD1. However, the minor allele of rs1054411 increased SCD1 expression in the presence of various FAs. Moreover, this variant was predicted in silico and verified in vitro to reduce the binding of ETS1 transcription factor to SCD1 promoter. Although we could not confirm an association with type 2 diabetes mellitus, the FA-dependent and ETS1-mediated effect of rs1054411 polymorphism deserves further investigation as it may modulate the development of lipid metabolism-related conditions.

Downregulation of circular RNA ETS1 promotes SLE activity and inhibits Treg cell differentiation through miR-1205/FoxP3 molecular axis.

PURPOSE: This study aimed to explore the mechanism by which systemic lupus erythematosus (SLE) activity is promoted through Treg inhibition from the perspective of ceRNA. METHODS: qRT-PCR was used to detect the expressions of circETS1, miR-1205, and FoxP3 in clinical SLE patient samples. Overexpression of circETS1and miR-1205, along with knockdown of miR-1205 and FoxP3 were conducted in CD4+ T cells, while the proliferation of helper T cell 17 (Th17) and regulatory T cell (Treg) was detected. Arescue assay was performed to verify the molecular mechanism of circETS1/miR-1205/Foxp3 mRNA axis in regulating CD4+ T cell differentiation. In the in vivo experiment, the expression of miR-1205 in SLE mice was intervened, and renal function, inflammatory factors, and serum complement were measured. Additionally, Treg/Th17 cell ratio was detected by flow cytometry. RESULTS: In SLE patients, Treg cells were found to decrease, while Th17 cells increased. Transfection with circETS1 overexpression led to CD4+ T cells differentiating into Treg cells, causing an imbalance in the Th17/Treg ratio. Transfection of miR-1205 mimic and si-FoxP3 could reverse the effect of circETS1 overexpression. Moreover, inhibiting the expression of miR-1205 showed therapeutic effects on SLE mice. CONCLUSION: circETS1 inhibits Treg via the miR-1205/FoxP3 axis, thereby promoting SLE activity, which may become a new target for SLE treatment.

SLC9A2, suppressing by the transcription suppressor ETS1, restrains growth and invasion of osteosarcoma via inhibition of aerobic glycolysis.

Recent studies have shown that Solute Carrier Family 9 Member A2 (SLC9A2) could serve as a biomarker for cancer. However, its mechanism of action in osteosarcoma (OS) was still unclear. In this study, the data sets GSE154530 and GSE99671 were downloaded from the Gene Expression Omnibus (GEO) database, and 31 differentially expressed genes (DEGs) related to methylation were screened by bioinformatics analysis tools. Subsequently, SLC9A2 was screened as a candidate gene from DEGs, which was significantly downregulated in OS. CCK-8, transwell, western blotting and Seahorse XFe24 Cell Metabolic Analyzer assays demonstrated that overexpression of SLC9A2 could constrain OS cell proliferation, invasion, and aerobic glycolysis. Dual-luciferase reporter gene assay and chromatin immunoprecipitation (ChIP) assays indicated ETS proto-oncogene 1 (ETS1) was a transcription suppressor of SLC9A2, and overexpression of ETS1 could promote methylation levels in specific regions of the SLC9A2 promoter. ETS1 could promote the proliferation, invasion, and aerobic glycolysis ability of OS cells, as well as tumor growth in vivo by inhibiting the expression of SLC9A2. In addition, SLC9A2, suppressing by ETS1, restrains growth and invasion of OS via inhibition of aerobic glycolysis. Thus, SLC9A2 can function as a key inhibitory factor in the aerobic glycolysis to inhibit proliferation and invasion of OS. This indicated that SLC9A2 has a potential targeted therapeutic effect on OS.

LINC00922 decoys SIRT3 to facilitate the metastasis of colorectal cancer through up-regulation the H3K27 crotonylation of ETS1 promoter.

BACKGROUND: Lysine crotonylation (Kcr) is up-regulation in colorectal cancer (CRC) tissues, while its specific contribution remains uncertain. This study aimed to elucidate the role and mechanism of crotonylation on Lys27 of histone H3 (H3K27cr) in facilitating CRC metastasis. METHODS: Immunohistochemistry was employed to investigate the correlation between H3K27cr and CRC metastasis. Both in vitro and in vivo assays employing loss function or gain function approaches were conducted to elucidate the role of LINC00922 in promoting CRC metastasis. ScRNA-seq analysis and immunoprecipitation analyses were employed to explore the underlying mechanism by which LINC00922 facilitates CRC metastasis through H3K27cr. RESULTS: Clinically, H3K27cr was upregulated in metastatic CRC tissues and positively correlated with advanced clinical stages. Functionally, knockdown of LINC00922 inhibited migration of CRC cells both in vitro and in vivo. Furthermore, the supplementation of NaCr restored the migration and invasion levels of LINC00922 stable knockdown cells by restoring the H3K27cr level. Mechanistically, LINC00922 promoted invasion and migration through H3K27cr mediated cell adhesion molecules (CAMs) in epithelial cells. Notably, LINC00922 interacted with the protein sirtuin 3 (SIRT3) and obstructed its binding to the promoter region of ETS1, leading to an elevation in the level of H3K27cr in this promoter region and the subsequent activation of ETS1 transcription. CONCLUSIONS: Our findings uncovered a novel regulatory function of H3K27cr, regulated by LINC00922, in facilitating CRC metastasis. This discovery contributed to a deeper comprehension of the involvement of histone crotonylation in the metastatic process of CRC.

Ets-1 transcription factor regulates glial cell regeneration and function in planarians.

Glia play multifaceted roles in nervous systems in response to injury. Depending on the species, extent of injury and glial cell type in question, glia can help or hinder the regeneration of neurons. Studying glia in the context of successful regeneration could reveal features of pro-regenerative glia that could be exploited for new human therapies. Planarian flatworms completely regenerate their nervous systems after injury - including glia - and thus provide a strong model system for exploring glia in the context of regeneration. Here, we report that planarian glia regenerate after neurons, and that neurons are required for correct glial numbers and localization during regeneration. We also identify the planarian transcription factor-encoding gene ets-1 as a key regulator of glial cell maintenance and regeneration. Using ets-1 (RNAi) to perturb glia, we show that glial loss is associated with altered neuronal gene expression, impeded animal movement and impaired nervous system architecture - particularly within the neuropil. Importantly, our work reveals the inter-relationships of glia and neurons in the context of robust neural regeneration.

An update on the roles of transcription factor Ets1 in autoimmune diseases.

Transcription factors are crucial to regulate gene expression in immune cells and in other cell types. In lymphocytes, there are a large number of different transcription factors that are known to contribute to cell differentiation and the balance between quiescence and activation. One such transcription factor is E26 oncogene homolog 1 (Ets1). Ets1 expression is high in quiescent B and T lymphocytes and its levels are decreased upon activation. The human ETS1 gene has been identified as a susceptibility locus for many autoimmune and inflammatory diseases. In accord with this, gene knockout of Ets1 in mice leads to development of a lupus-like autoimmune disease, with enhanced activation and differentiation of both B cells and T cells. Prior reviews have summarized functional roles for Ets1 based on studies of Ets1 knockout mice. In recent years, numerous additional studies have been published that further validate ETS1 as a susceptibility locus for human diseases where immune dysregulation plays a causative role. In this update, new information that further links Ets1 to human autoimmune diseases is organized and collated to serve as a resource. This update also describes recent studies that seek to understand molecularly how Ets1 regulates immune cell activation, either using human cells and tissues or mouse models. This resource is expected to be useful to investigators seeking to understand how Ets1 may regulate the human immune response, particularly in terms of its roles in autoimmunity and inflammation. This article is categorized under: Immune System Diseases > Genetics/Genomics/Epigenetics Immune System Diseases > Molecular and Cellular Physiology.

ETS1 Ameliorates Hyperoxia-Induced Bronchopulmonary Dysplasia in Mice by Activating Nrf2/HO-1 Mediated Ferroptosis.

PURPOSE: Bronchopulmonary dysplasia (BPD) is associated with hyperoxia-induced oxidative stress-associated ferroptosis. This study examined the effect of E26 oncogene homolog 1 (ETS1) on oxidative stress-associated ferroptosis in BPD. METHODS: Hyperoxia-induced A549 cells and neonatal mice were used to establish BPD models. The effects of ETS1 on hyperoxia-induced ferroptosis-like changes in A549 cells were investigated by overexpression of ETS1 plasmid transfection and erastin treatment. Glucose consumption, lactate production, and NADPH levels were assessed by the glucose, lactate, and NADP+/NADPH assay kits, respectively. The potential regulatory relationship between ETS1 and Nrf2/HO-1 was examined by treating hyperoxia-induced A549 cells with the Nrf2 inhibitor ML385. ETS1 effect on the Nrf2 promoter was explored by dual-luciferase reporter and chromatin immunoprecipitation assay. The effect of ETS1 on the symptoms of BPD mice was examined by injecting an adenovirus overexpressing ETS1. RESULTS: ETS1 overexpression increased hyperoxia-induced cell viability, glucose consumption, lactate production, and NADPH levels and reduced inflammation and apoptosis in A549 cells. In animal experiments, ETS1 overexpression prevented weight loss, airway enlargement, and reductions in radial alveolar counts in BPD mice, while reducing the mean linear intercept, mean alveolar diameter and inflammation. ETS1 overexpression suppressed PTGS2 and CHAC1 expression, reduced ROS, MDA and ferrous iron (Fe2+) production and increased GSH levels in hyperoxia-induced A549 cells and BPD mice. In addition, ETS1 can bind to the Nrf2 promoter region and thus promote Nrf2 transcription. ETS1 overexpression increased the mRNA and protein levels of Nrf2, HO-1, xCT, and GPX4 in hyperoxia-induced A549 cells and BPD mice. In hyperoxia-induced A549 cells, erastin and ML385 treatment abolished the effect of ETS1 overexpression. CONCLUSION: ETS1 is important in oxidative stress-related ferroptosis in a hyperoxia-induced BPD model, and the effect is partially mediated by the Nrf2/HO-1 axis.

Establishment of the lymphoid ETS-code reveals deregulated ETS genes in Hodgkin lymphoma.

The human family of ETS transcription factors numbers 28 genes which control multiple aspects of development, notably the differentiation of blood and immune cells. Otherwise, aberrant expression of ETS genes is reportedly involved in forming leukemia and lymphoma. Here, we comprehensively mapped ETS gene activities in early hematopoiesis, lymphopoiesis and all mature types of lymphocytes using public datasets. We have termed the generated gene expression pattern lymphoid ETS-code. This code enabled identification of deregulated ETS genes in patients with lymphoid malignancies, revealing 12 aberrantly expressed members in Hodgkin lymphoma (HL). For one of these, ETS gene ETV3, expression in stem and progenitor cells in addition to that in developing and mature T-cells was mapped together with downregulation in B-cell differentiation. In contrast, subsets of HL patients aberrantly overexpressed ETV3, indicating oncogenic activity in this B-cell malignancy. Analysis of ETV3-overexpressing HL cell line SUP-HD1 demonstrated genomic duplication of the ETV3 locus at 1q23, GATA3 as mutual activator, and suppressed BMP-signalling as mutual downstream effect. Additional examination of the neighboring ETS genes ETS1 and FLI1 revealed physiological activities in B-cell development and aberrant downregulation in HL patient subsets. SUP-HD1 showed genomic loss on chromosome 11, del(11)(q22q25), targeting both ETS1 and FLI1, underlying their downregulation. Furthermore, in the same cell line we identified PBX1-mediated overexpression of RIOK2 which inhibited ETS1 and activated JAK2 expression. Collectively, we codified normal ETS gene activities in lymphopoiesis and identified oncogenic ETS members in HL.

MiR-193b-3p Regulates TLR4 Expression to Inhibit Inflammation by Targeting ETS1 in Allergic Rhinitis.

INTRODUCTION: Allergic rhinitis (AR) is identified as a multifactorial disease caused by the interaction of genes and surroundings, which is difficult to cure. MicroRNAs were reported to be engaged in AR development. Here, we aimed to seek the anti-inflammatory effects and regulatory mechanism of miR-193b-3p in AR. METHODS: Mucosal tissues from AR patients and healthy volunteers were collected, and human nasal epithelial cells (HNECs) were treated with IL-13 to establish a cell model of AR. The gene expression of miR-193b-3p, ETS1, TLR4, GM-CSF, eotaxin, and MUC5AC was determined by RT-qPCR. The protein levels of ETS1 and TLR4 were examined using Western blot. Enzyme-linked immunosorbent assay was performed to measure protein concentration of GM-CSF, eotaxin, and MUC5AC in cell supernatant. Dual luciferase assay was applied to verify the interaction among miR-193b-3p, ETS1, and TLR4. RESULTS: The expression of miR-193b-3p was declined in clinical samples from AR patients and in IL-13-induced HNECs, while the mRNA and protein levels of ETS1 and TLR4 were elevated. MiR-193b-3p overexpression or ETS1 silencing notably decreased the mRNA and protein levels of GM-CSF, eotaxin, and MUC5AC in IL-13-treated HNECs. Mechanistically, miR-193b-3p directly combined with ETS1 to silence ETS1 expression. ETS1 promoted the transcriptional activity of TLR4 through interacting with TLR4 promoter. Furthermore, rescue experiments revealed that ETS1 overexpression abolished miR-193b-3p sufficiency-mediated suppression of the mRNA and protein levels of GM-CSF, eotaxin, and MUC5AC in IL-13-treated HNECs. Similarly, TLR4 overexpression compromised the inhibitory impacts of ETS1 downregulation on the mRNA and protein levels of GM-CSF, eotaxin, and MUC5AC in IL-13-induced HNECs. DISCUSSION: MiR-193b-3p repressed IL-13-induced inflammatory response in HNECs by suppressing ETS1/TLR4 axis, which indicated that miR-193b-3p might be a therapeutic target for AR treatment.

LncRNA HOTAIRM1 promotes osteogenic differentiation of human bone marrow-derived mesenchymal stem cells by targeting miR-152-3p/ETS1 axis.

BACKGROUND: Bone marrow mesenchymal stem cells (BMSCs) can differentiate into osteoblasts and thus present a tremendous therapeutic potential in osteoporosis. Here, we elucidated the involvement of long non-coding RNAs (lncRNAs) HOXA transcript antisense RNA, myeloid-specific 1 (HOTAIRM1) in the osteogenic differentiation of BMSCs. METHODS AND RESULTS: The expression levels of HOTAIRM1, miR-152-3p, ETS proto-oncogene 1 (ETS1), runt-related transcription factor 2 (RUNX2), Osterix, and osteocalcin (OCN) were determined by a quantitative real-time polymerase chain reaction (qRT-PCR) or western blot method. Targeted relationship between miR-152-3p and HOTAIRM1 or ETS1 was confirmed by dual-luciferase reporter and RNA pull-down assays. The activity of alkaline phosphatase (ALP) was measured by the ALP Activity Assay Kit. The extent of the calcium deposition was assessed by Alizarin Red Staining. Our data showed that HOTAIRM1 and ETS1 levels were up-regulated and miR-152-3p expression was down-regulated during osteogenic differentiation of human BMSCs (HBMSCs). HOTAIRM1 overexpression enhanced osteogenic differentiation of HBMSCs, and decreased level of HOTAIRM1 suppressed osteogenic differentiation of HBMSCs. HOTAIRM1 directly targeted miR-152-3p. ETS1 was identified as a direct and functional target of miR-152-3p. Furthermore, HOTAIRM1 functioned as a post-transcriptional regulator of ETS1 expression by miR-152-3p. CONCLUSION: The findings in this paper identify HOTAIRM1 as a novel regulator of osteogenic differentiation of BMSCs by the regulation of miR-152-3p/ETS1 axis, uncovering HOTAIRM1 as a promising therapeutic strategy for osteoporosis.

NF-κB/p52 augments ETS1 binding genome-wide to promote glioma progression.

Gliomas are highly invasive and chemoresistant cancers, making them challenging to treat. Chronic inflammation is a key driver of glioma progression as it promotes aberrant activation of inflammatory pathways such as NF-κB signalling, which drives cancer cell invasion and angiogenesis. NF-κB factors typically dimerise with its own family members, but emerging evidence of their promiscuous interactions with other oncogenic factors has been reported to promote transcription of new target genes and function. Here, we show that non-canonical NF-κB activation directly regulates p52 at the ETS1 promoter, activating its expression. This impacts the genomic and transcriptional landscape of ETS1 in a glioma-specific manner. We further show that enhanced non-canonical NF-κB signalling promotes the co-localisation of p52 and ETS1, resulting in transcriptional activation of non-κB and/or non-ETS glioma-promoting genes. We conclude that p52-induced ETS1 overexpression in glioma cells remodels the genome-wide regulatory network of p52 and ETS1 to transcriptionally drive cancer progression.

Distinct Prognostic and Immunological Roles of ETS1 and ETS2: A Pan-Cancer Analysis.

Objective: ETS1 and ETS2, the main ETS family of transcription factors, have been found to act as downstream effectors of the RAS/MAPK pathway. This study explores the expression and prognostic values of ETS1 and ETS2 across cancers. We also aimed to explore the significance of ETS1 and ETS2 expression in normal immune cells with relation to tumorigenesis. Methods: The expression of ETS1 and ETS2 was examined in the HPA and GEPIA2 databases. The KM plotter was applied to examine prognostic value of ETS1 and ETS2. Correlation between ETS1/ETS2 and infiltrating immune cells and immune checkpoints was assessed using TIMER2.0. The mutation landscape of ETS1/ETS2 was explored using the cBioPortal. STRING and GEPIA2 were used to screen ETS1/ETS2 binding and correlated genes. Enrichr was applied to perform GO and KEGG enrichment analyses. Results: ETS1 showed enhanced expression in lymphoid tissue, while ETS2 showed low tissue specificity. ETS1 was increased in 12 and decreased in 6 cancers, while ETS2 was increased in 4 and decreased in 13 cancers. Both ETS1 and ETS2 were favorable prognostic markers in LIHC and KIRC, while they showed different prognostic roles in more cancers. ETS1 showed stronger correlation with several infiltrating immune cells and immune checkpoints compared with ETS2. Both ETS1 and ETS2 harbored low mutation ratio. ETS1 interacting and correlated genes were enriched in GO terms in response to cadmium ion and response to oxidative stress, while those of ETS2 were enriched in transcription regulation. Conclusion: ETS1 and ETS2 showed different patterns in expression, prognostic values, correlation with immune infiltrating, and immune checkpoints. ETS1 and ETS2 play distinct roles across cancer.

ETS1-HMGA2 Axis Promotes Human Limbal Epithelial Stem Cell Proliferation.

Purpose: This study aimed to investigate the role and molecular mechanism of ETS1 in the proliferation and differentiation of human limbal epithelial stem cells (LESCs). Methods: RNA-seq and quantitative real-time PCR were used to determine gene expression changes when ETS1 and HMGA2 was knocked down using short-hairpin RNAs or overexpressed by lentivirus. Immunofluorescence and flow cytometry experiments were performed to assess the roles of ETS1 and HMGA2 in LESC proliferation. ETS1-bound cis-regulatory elements and target genes in LESCs were identified using chromatin immunoprecipitation sequencing. The epigenetic features of ETS1-binding sites were assessed by the published histone modification and chromatin accessibility profiles. Results: ETS1 was robustly expressed in LESCs but dramatically reduced on differentiation into corneal epithelial cells (CECs). ETS1 knockdown in LESCs inhibited cellular proliferation and activated CEC markers (KRT3, KRT12, CLU, and ALDH3A1). When ETS1 was overexpressed during CEC differentiation, LESC-associated genes were upregulated while CEC-associated genes were downregulated. The genome-wide binding profile of ETS1 was identified in LESCs. ETS1 occupied H3K4me3-marked promoters and H3K27ac/H3K4me1-marked enhancers. ETS1-binding sites were also enriched for chromatin accessibility signal. HMGA2 showed a consistent expression pattern with ETS1. ETS1 activates HMAG2 by binding to its promoter. Knockdown and overexpression experiments suggested that HMGA2 can promote LESC proliferation and inhibits its differentiation. Conclusions: ETS1 promotes LESC proliferation and inhibits its differentiation via activating HMGA2.

Defective binding of ETS1 and STAT4 due to a mutation in the promoter region of THPO as a novel mechanism of congenital amegakaryocytic thrombocytopenia.

Congenital amegakaryocytic thrombocytopenia (CAMT) is a recessive disorder characterized by severe reduction of megakaryocytes and platelets at birth, which evolves toward bone marrow aplasia in childhood. CAMT is mostly caused by mutations in MPL (CAMT-MPL), the gene encoding the receptor of thrombopoietin (THPO), a crucial cytokine regulating hematopoiesis. CAMT can be also due to mutations affecting the THPO coding region (CAMT-THPO). In a child with the clinical picture of CAMT, we identified the homozygous c.-323C>T substitution, affecting a potential regulatory region of THPO. Although mechanisms controlling THPO transcription are not characterized, bioinformatics and in vitro analysis showed that c.-323C>T prevents the binding of transcription factors ETS1 and STAT4 to the putative THPO promoter, impairing THPO expression. Accordingly, in the proband the serum THPO concentration indicates defective THPO production. Based on these findings, the patient was treated with the THPO-mimetic agent eltrombopag, which induced a significant increase in platelet count and stable remission of bleeding symptoms. Herein, we report a novel pathogenic variant responsible for CAMT and provide new insights into the mechanisms regulating transcription of the THPO gene.

Laminins in tumor-derived exosomes upregulated by ETS1 reprogram omental macrophages to promote omental metastasis of ovarian cancer.

Tumor-derived exosomes participate in omental metastatic colonization of ovarian cancer by inducing an adaptive response in the tumor microenvironment. However, cell-cell communication via exosomes between primary tumor cells and the microenvironment of distant omentum and the mechanism of pre-metastatic niche formation are poorly understood. Here, we demonstrated that ETS1-overexpressing ovarian cancer cells secreted larger exosomes with higher laminin levels. In addition, ovarian cancer exosomes could be taken up by omental macrophages through integrin and laminin interaction. Compared with control exosomes, exosomes derived from ETS1-overexpressing ovarian cancer cells (LV-ETS1 Exos) stimulated the polarization of more macrophages toward the M2 phenotype (CD163 marker), as well as the production of more CXCL5 and CCL2 in macrophages, via integrin αvß5/AKT/Sp1 signaling. In vivo experiments showed that LV-ETS1 Exos promoted omental metastasis of ovarian cancer by mediating the tumor-promoting effect of macrophages, which could be neutralized by integrin ανß5 inhibitor cilengitide. These results indicated that ETS1 could drive ovarian cancer cells to release exosomes with higher laminin levels, thereby accelerating the exosome-mediated pro-metastatic effects of omental macrophages via the integrin αvß5/AKT/Sp1 signaling pathway, and the integrin ανß5 inhibitor cilengitide could inhibit omental metastasis of ovarian cancer driven by tumor-derived exosomes.

Role of m6A modification and novel circ_0066715/ miR-486-5p/ ETS1 axis in rheumatoid arthritis macrophage polarization progression.

Rheumatoid arthritis (RA) is a systemic disease dominated by inflammatory synovitis. RA synovial macrophages tend undergo M1-type macrophage polarization. Then, polarized M1-type macrophages secrete abundant pro-inflammatory cytokines, causing joint and cartilage destruction. N6-methyladenosine (m6A) methylation modification, circular RNA (circRNA), microRNA (miRNA), messenger RNA (mRNA), etc. are involved in the inflammatory response of RA. We found that there is an imbalance of inflammatory polarization in RA, which is manifested by a sharp increase in inflammatory markers and a high inflammatory response. Here, we show that RA was closely associated with low expression of circ_0066715. The overexpression of circ_0066715 significantly increased the ETS1 levels in RA-FLS cells, decreased cytokine secretion by M1-type macrophages, elevated M2-type cytokines, and inhibited FLS proliferation. Interestingly, the overexpression of miR-486-5p significantly suppressed the attenuation of the cell function and the effect on M1 macrophage polarization caused by circ_0066715 positive expression. WTAP may be involved in the methylation process of ETS1 in RA. ETS1 m6A methylation levels were altered upon WTAP intervention. The overexpression or interference of circ_0066715 decreased or increased WTAP expression. Our findings provide a novel circRNA/miRNA/mRNA regulatory axis and m6A regulatory mechanism involved in the process of RA macrophage polarization, thereby providing a powerful diagnostic and therapeutic strategy for RA treatment.