Construction of gastric cancer prognostic signature based on the E26 transcription factor and the identification of novel oncogene ELK3.

The aim of the present study was to investigate the function of 29 E26 (ETS) transcription factor families in gastric cancer (GC) and determine their association with prognosis. Our analysis of the expression of the ETS family revealed that 28 genes were dysregulated in GC, and that their expression was associated with multiple clinicopathological features (P<0.05). Based on the expression signature of the ETS family, consensus clustering was performed to generate two gastric cancer subtypes. These subtypes exhibited differences in overall survival (OS, P = 0.161), disease-free survival (DFS, P<0.05) and GC grade (P<0.01). Functional enrichment analysis of the target genes associated with the ETS family indicated that these genes primarily contribute to functions that facilitate tumor progression. A systematic statistical analysis was used to construct a prognostic model related to OS and DFS in association with the ETS family. This model demonstrated that the maximum area under the curve (AUC) values for predicting OS and DFS were 0.729 and 0.670, respectively, establishing ETS as an independent prognostic factor for GC Furthermore, a nomogram was created from the prognostic signature, and its predictive accuracy was confirmed by a calibration curve. Finally, the expression and prognostic significance of the six genes comprising the model were also examined. Among these, ELK3 was found to be significantly overexpressed in GC clinical samples. Subsequent in vitro and in vivo studies verified that ELK3 regulates GC proliferation and metastasis, highlighting its potential as a therapeutic target for gastric cancer.

Early Progression of Abdominal Aortic Aneurysm is Decelerated by Improved Endothelial Barrier Function via ALDH2-LIN28B-ELK3 Signaling.

The involvement of endothelial barrier function in abdominal aortic aneurysm (AAA) and its upstream regulators remains unknown. Single-cell RNA sequencing shows that disrupted endothelial focal junction is an early (3 days) and persistent (28 days) event during Angiotensin II (Ang II)-induced AAA progression. Consistently, mRNA sequencing on human aortic dissection tissues confirmed downregulated expression of endothelial barrier-related genes. Aldehyde dehydrogenase 2 (ALDH2), a negative regulator of AAA, is found to be upregulated in the intimal media of AAA samples, leading to testing its role in early-stage AAA. ALDH2 knockdown/knockout specifically in endothelial cells (ECs) significantly increases expression of EC barrier markers related to focal adhesion and tight junction, restores endothelial barrier integrity, and suppresses early aortic dilation of AAA (7 and 14 days post-Ang II). Mechanically, ELK3 acts as an ALDH2 downstream regulator for endothelial barrier function preservation. At the molecular level, ALDH2 directly binds to LIN28B, a regulator of ELK3 mRNA stability, hindering LIN28B binding to ELK3 mRNA, thereby depressing ELK3 expression and impairing endothelial barrier function. Therefore, preserving vascular endothelial barrier integrity via ALDH2-specific knockdown in ECs holds therapeutic potential in the early management of AAAs.

ETS transcription factor ELK3 in human cancers: An emerging therapeutic target.

Cancer is a genetic and complex disorder, resulting from several events associated with onset, development, and metastasis. Tumor suppressors and oncogenes are among the main regulators of tumor progression, contributing to various cancer-related behaviors like cell proliferation, invasion, migration, epithelial-mesenchymal transition (EMT), cell cycle, and apoptosis. Transcription factors (TFs) could act as tumor suppressors or oncogenes in cancer progression. E-twenty-six/E26 (ETS) family of TFs have a winged helix-turn-helix (HLH) motif, which interacted with specific DNA regions with high levels of purines and GGA core. ETS proteins act as transcriptional repressors or activators to modulate the expression of target genes. ETS transcription factor ELK3 (ELK3), as a type of ETS protein, was shown to enhance in various cancers, suggesting that it may have an oncogenic role. These studies indicated that ELK3 promoted invasion, migration, cell cycle, proliferation, and EMT, and suppressed cell apoptosis. In addition, these studies demonstrated that ELK3 could be a promising diagnostic and prognostic biomarker in human cancer. Moreover, accumulating data proved that ELK3 could be a novel chemoresistance mediator in human cancer. Here, we aimed to explore the overall change of ELK3 and its underlying molecular mechanism in human cancers. Moreover, we aimed to investigate the potential role of ELK3 as a prognostic and diagnostic biomarker as well as its capability as a chemoresistance mediator in cancer.

ELK3 Targeting AEG1 Promotes Migration and Invasion of Ovarian Cancer Cells under Hypoxia.

Ovarian cancer (OC) is one of the most common tumors in female reproductive organs with a five-year survival rate of less than 45%. Metastasis is a crucial contributor to OC development. ETS transcription factor (ELK3), as a transcriptional factor, have been involved in multiple tumor development. However, its role in OC remains elusive. In this study, we observed high expression of ELK3 and AEG1 in human OC tissues. OVCAR-3 and SKOV3 cells were treated with hypoxia to mimic tumor microenvironment in vivo. We found that the expression of ELK3 was significantly increased in cells under hypoxia compared with normoxia. ELK3 knockdown inhibited cell migration and invasion abilities under hypoxia. Moreover, ELK3 knockdown decreased ß-catenin expression and inhibited the activation of Wnt/ß-catenin pathway in SKOV3 cells under hypoxia. Astrocyte-elevated gene-1 (AEG1) has been reported to promote OC progression. Our results showed that the mRNA level of AEG1 was decreased when ELK3 knockdown under hypoxia. Dural luciferase assay confirmed that ELK3 bound to gene AEG1 promoter (-2005-+15) and enhanced its transcriptional activity under hypoxia. Overexpression of AEG1 increased the migration and invasion abilities of SKOV3 cell with ELK3 knockdown. In the absence of ELK3, the activation of ß-catenin was recovered by AEG1 overexpression. To sum up, we conclude that ELK3 promotes AEG1 expression by binding to its promoter. ELK3 could promote migration and invasion of OC cells by targeting AEG1, which provides a potential basis for therapeutic approaches to OC.

Glioma angiogenesis is boosted by ELK3 activating the HIF-1[Formula: see text]/VEGF-A signaling axis.

BACKGROUND: Clinical studies have shown that first-line use of anti-angiogenetic therapy can prolong progression-free survival but little progress has been made in extending the overall survival of the patients. We explored the role of ELK3 in glioma angiogenesis to improve and design more efficacious therapies. METHODS: A tissue microarray and immunohistochemistry analysis were used to determine the expression of ELK3 protein in 400 glioma patients. Cell proliferation, metastasis, cell cycle, and apoptosis were monitored in U87 and U251 cells using CCK-8, EdU, transwell assays, and flow cytometry. A tube-formation assay, a rat aorta ring sprouting assay, and a matrigel plug assay were performed to examine the antiangiogenic activity of ELK3. An ELISA, Western blot, and correlation analysis of the CGGA dataset were used to detect the association between ELK3 and VEGF-A or ELK3 and HIF-1[Formula: see text]. Besides, orthotopic transplantation in nude mice and histopathological and immunological analysis of in vitro tumors were used to explore the effect of ELK3 on tumor progression and median survival. RESULTS: ELK3 was upregulated in glioma tissues and associated with a poor prognosis. In vitro, ELK3 promoted cell proliferation and cell cycle progression, induced metastasis, and suppressed apoptosis. Then, silencing ELK3 inhibited VEGF-A expression and secretion by facilitating HIF-1[Formula: see text] degradation via ubiquitination. Finally, knockdown ELK3 inhibited tumor progression and angiogenesis in vitro and in vivo, as well as prolonged nude mice's median survival. CONCLUSIONS: Our findings first evidenced that ELK3 is crucial for glioma because it promotes angiogenesis by activating the HIF-1[Formula: see text]/VEGF-A signaling axis. Therefore, we suggest that ELK3 is a prognostic marker with a great potential for glioma angiogenesis and ELK3-targeted therapeutic strategies might hold promise in improving the efficacy of anti-angiogenic therapies.

ELK3-CXCL16 axis determines natural killer cell cytotoxicity via the chemotactic activity of CXCL16 in triple negative breast cancer.

Triple-negative breast cancer (TNBC) is the most challenging subtype of breast cancer because of its aggressive behavior and the limited therapeutic strategies available. In the last decade, immunotherapy has become a promising treatment to prolong survival in advanced solid cancers including TNBC. However, the efficacy of immunotherapy in solid cancers remains limited because solid tumors contain few tumor-infiltrating lymphocytes. Here, we show that targeting an ETS transcription factor ELK3 (ELK3) recruits immune cells including natural killer (NK) cells into tumors via the chemotactic activity of chemokine. ELK3 depletion increases CXCL16 expression level and promotes NK cell cytotoxicity through CXCL16-mediated NK cell recruitment in TNBC. In silico analysis showed that ELK3 is negatively correlated with CXCL16 expression in breast cancer patient samples. Low expression of ELK3 and high expression of CXCL16 were associated with a better prognosis. Low expression of ELK3 and high expression of CXCL16 were associated with increased expression of NK cell-related genes. Our findings demonstrate that the ELK3-CXCL16 axis modulates NK cell recruitment to increase NK cell cytotoxicity, suggesting that targeting the ELK3 gene could be an adjuvant strategy for increasing the efficacy of immunotherapy in TNBC.

Deubiquitinase UCHL5 stabilizes ELK3 to potentiate cancer stemness and tumor progression in pancreatic adenocarcinoma (PAAD).

Aberrant ubiquitin-proteasome system (UPS) contributes to tumorigeneisis or drug resistance of Pancreatic Adenocarcinoma (PAAD). Previous studies have implicated the deubiquitinase UCHL5 was abnormally expressed in multiple malignancies. However, little was reported about the specific roles of UCHL5 in PAAD. We aimed to identify the biological roles of UCHL5 in PAAD and demonstrate its prognostic significance. Differential analysis revealed that UCHL5 expressed highly in tumors versus normal tissues, like TCGA-PAAD, GSE28735, GSE15471 and collected samples. Patients with high UCHL5 expressions had worse survival outcomes relative to those with low UCHL5 levels. Experimental assays showed that UCHL5 overexpression could significantly enhance cell proliferation, colony formation and self-renewal capacities. UCHL5 could also promote PAAD migration in vitro and in vivo. Mechanistically, UCHL5 could directly deubiquitinate and stabilize ELK3 proteins. UCHL5 relied on accumulated ELK3 proteins to drive cell growth, stem-like properties and migration abilities. In addition, enrichment analysis based on RNA-seq data implicated that ELK3 mainly correlated with Notch1 signaling and ELK3 could notably elevate ELK3 mRNA levels. UCHL5 could thus promote self-renewal abilities of PAAD and targeting ELK3 could inhibit the stemness features. In contrast, UCHL5 deficiency could suppress PAAD stemness features, and ectopic expression of ELK3 could rescue this effect. Last of all, we utilized the UCHL5 inhibitor, b-AP15, to treat PAAD cells and found that b-AP15 could inhibit the growth of PAAD cells in a dose-dependent manner. Collectively, our study uncovered the underlying mechanisms of UCHL5/ELK3/Notch1 axis in PAAD progression and stemness maintaince, shedding light on individualized treatment and risk stratification for PAAD patients.

Circular RNA hsa_circ_0000144 aggravates ovarian Cancer progression by regulating ELK3 via sponging miR-610.

BACKGROUND: Ovarian cancer is a common cause of death among women and a health problem worldwide. Circ_0000144 has been confirmed to be an oncogene involved in cancer progression, such as gastric cancer. However, the role of circ_0000144 in ovarian cancer remains unclear and needs to be elucidated. This retrospective study aimed to investigate the underlying mechanism of circ_0000144 in ovarian cancer. METHODS: Differentially expressed circ_0000144 expression in ovarian cancer and normal tissues was identified by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). In vitro assays were performed to explore the biological functions of circ_0000144 in ovarian cancer cells. An in vivo xenograft model was used to investigate the efficacy of circ_0000144 in the progression of ovarian cancer. RESULTS: Circ_0000144 was significantly upregulated in ovarian cancer cells and tissues. Circ_0000144 overexpression significantly promoted ovarian cancer cell proliferation, migration, and invasion. This study further demonstrated that circ_0000144 downregulated ELK3 levels by sponging miR-610 in ovarian cancer cells. Moreover, circ_0000144 significantly promotes ovarian cancer tumorigenesis in vivo. CONCLUSION: Our data indicate that circ_0000144 could enhance the carcinogenesis of ovarian cancer by specifically targeting miR-610, which may serve as a novel target for the diagnosis and prognosis of ovarian cancer.

RREB1 promotes the development of parafollicular carcinogenesis through the Ras-Raf-1-ELK3 signaling pathway.

Thyroid cancer (TC) is the most common endocrine malignancy. Medullary thyroid carcinoma (MTC) is derived from parathyroid follicle cells (C cells) secrete calcitonin, accounting for approximately 5-10% of all thyroid cancers. The malignancy is between differentiated and undifferentiated thyroid cancer and undifferentiated thyroid cancer and has a relatively poor prognosis. In MTC tumor cells, RREB1 regulates the differentiation of parathyroid cells via RAS-Raf-1-ELK3 signaling and induce calcitonin secretion. Therefore, it is easy to induce parathyroid parafollicular cells canceration and medullary thyroid carcinoma. Here, we investigated the correlation between RREB1, RAS-Raf-1-ELK3 signaling pathway and medullary thyroid carcinoma with various phases. Our results suggest that RREB1 promotes parafollicular carcinoma through the Ras-Raf1-elk3 signaling pathway, providing a rationale to further investigate the role of RREB1 in parafollicular carcinoma. It provides theoretical guidance for the clinical treatment of medullary thyroid cancer.

ELK3 Controls Gastric Cancer Cell Migration and Invasion by Regulating ECM Remodeling-Related Genes.

Current therapeutic strategies for gastric cancer, including surgery and chemotherapy improve patient survival; however, the survival rate of patients with metastatic gastric cancer is very low. The molecular mechanisms underlying the dissemination of gastric cancer cells to distant organs are currently unknown. Here, we demonstrate that the E26 transformation-specific (ETS) transcription factor ELK3 (ELK3) gene is required for the migration and invasion of gastric cancer cells. The ELK3 gene modulates the expression of extracellular matrix (ECM) remodeling-related genes, such as bone morphogenetic protein (BMP1), lysyl oxidase like 2 (LOXL2), Snail family transcriptional repressor 1 (SNAI1), serpin family F member 1 (SERPINF1), decorin (DCN), and nidogen 1 (NID1) to facilitate cancer cell dissemination. Our in silico analyses indicated that ELK3 expression was positively associated with these ECM remodeling-related genes in gastric cancer cells and patient samples. The high expressions of ELK3 and other ECM remodeling-related genes were also closely associated with a worse prognosis of patients with gastric cancer. Collectively, these findings suggest that ELK3 acts as an important regulator of gastric cancer cell dissemination by regulating ECM remodeling.

[Expression characteristics and functional analysis of ELK3 in gastric cancer].

OBJECTIVE: To explore the expression characteristics of ELK3 and its role in the occurrence, progression and prognosis of gastric cancer. METHODS: We analyzed the expression characteristics of ELK3 in gastric cancer based on E-MTAB-6693 dataset and explored the prognostic value of ELK3 using Kaplan-Meier survival analysis and univariate and multivariate Cox regression analysis. Chip-Atlas, ChipBase, Genes Transcription Regulation Database, and hTFtarget were used for predicting the target genes of ELK3 and constructing the transcription regulation network. Functional enrichment analysis of the target genes was performed using R software. The proportions of infiltrating immune cells in gastric cancer were analyzed using Cibersort tool, and the Pearson coefficients between ELK3 and these cells were calculated. The expression profile of ELK3 was verified based on Gene Expression Profiling Interactive Analysis and Human Protein Atlas databases. We also collected 5 pairs of gastric cancer and adjacent tissue samples and detected the expression of ELK3 at both the mRNA and protein levels using RT-PCR and Western blotting. RESULTS: In public datasets and clinical samples, ELK3 was highly expressed in gastric cancer (P < 0.05), and its expression increased with the progression of M stage, AJCC stage, and perineural invasion (P < 0.05). ELK3 expression was correlated with N stage, AJCC stage, Lauren classification, differentiation, pathological classification, and microsatellite status of gastric cancer (P < 0.05). A high expression of ELK3 was associated with significantly reduced overall survival and disease-free survival of the patients, and served as an independent prognostic factor of gastric cancer (P < 0.05). Comprehensive analysis identified 176 potential target genes of ELK3, and enrichment analysis showed that ELK3 may regulate Rap1, AMPK, chemokines, VEGF, TNF, and tumor PD-L1/PD-1 signaling (PP < 0.05). The expression of ELK3 was negatively correlated with regulatory T cells, follicular helper T cells, and CD8+T cells in gastric cancer (P < 0.05). CONCLUSION: ELK3 acts as an oncogene in gastric cancer, and its high expression may promote the occurrence, progression and immune escape of gastric cancer.

ELK3 Mediated by ZEB1 Facilitates the Growth and Metastasis of Pancreatic Carcinoma by Activating the Wnt/ß-Catenin Pathway.

Rapid progression and metastasis are the major causes of death in patients with pancreatic ductal adenocarcinoma (PDAC). ELK3, a member of the ternary complex factor (TCF), has been associated with the initiation and progression of various cancers. However, the role of ELK3 in PDAC is not yet fully understood. Online databases and immunohistochemistry were used to analyze the ELK3 levels in PDAC tissues. The function of ELK3 was confirmed by a series of in vivo and in vitro studies. Western blotting and immunofluorescence were used to detect the molecular mechanisms of PDAC. ChIP-qPCR was used to study the mechanism responsible for the elevation of ELK3 expression in PDAC. The ELK3 levels were higher in PDAC tissues than in adjacent normal tissues. Functionally, we demonstrated that ELK3 acted as an oncogene to promote PDAC tumorigenesis and metastasis. Further study suggested that ELK3 promoted PDAC cell migration and invasion by activating the Wnt/ß-catenin pathway, and proved that ZEB1 could directly bind to the promoter of ELK3 to increase its transcription. Finally, both were associated with the patients' clinicopathological features and worse overall survival. Conclusively, our findings enrich the role of ELK3 in PDAC, and provide potential avenues for exploring more effective biomarkers and therapeutic strategies for the treatment of PDAC.

Methyltransferase-like protein 11A promotes migration of cervical cancer cells via up-regulating ELK3.

Cervical cancer is one of the common malignancies in women, which is characterized with high invasion and metastatic tendency in its advanced stage. Increasing evidence indicates that methyltransferase-like (METTL) gene family is involved in the progression of various cancers. However, the functional role of methyltransferase-like gene family in cervical cancer remains unclear. In the present study, we found that METTL11A, a member of the methyltransferase-like gene family, was significantly over-expressed in cervical carcinoma by analyzing TCGA database. This finding was further validated in clinical tissue samples. Moreover, ectopic expression of METTL11A in cervical cancer cell lines promoted cell proliferation and migration both in vitro and in vivo. Differential gene expression analysis in the transcriptomic sequencing data indicated that ELK3 was down-regulated in METTL11A-silenced cervical cancer cells, which was further verified at both protein and mRNA levels. Functional experiments identified that METTL11A promoted migration of cervical cancer cells in an ELK3-dependent manner. This study will promote understanding the mechanism of cervical cancer progression and the functional role of methyltransferase-like gene families in cancers.

Prognostic signature composed of transcription factors accurately predicts the prognosis of gastric cancer patients.

BACKGROUND: Transcription factors (TFs) are involved in important molecular biological processes of tumor cells and play an essential role in the occurrence and development of gastric cancer (GC). METHODS: Combined The Cancer Genome Atlas Program and Genotype-Tissue Expression database to extract the expression of TFs in GC, analyzed the differences, and weighted gene co-expression network analysis to extract TFs related to GC. The cohort including the training and validation cohort. Univariate Cox, least absolute contraction and selection operator (LASSO) regression, and multivariate Cox analysis was used for screening hub TFs to construct the prognostic signature in the training cohort. The Kaplan-Meier (K-M) and the receiver operating characteristic curve (ROC) was drawn to evaluate the predictive ability of the prognostic signature. A nomogram combining clinical information and prognostic signatures of TFs was constructed and its prediction accuracy was evaluated through various methods. The target genes of the hub TFs was predicted and enrichment analysis was performed to understand its molecular biological mechanism. Clinical samples and public data of GC was collected to verify its expression and prognosis. 5-Ethynyl-2'-deoxyuridine and Acridine Orange/Ethidium Bromide staining, flow cytometry and Western-Blot detection were used to analyze the effects of hub-TF ELK3 on the proliferation and apoptosis of gastric cancer in vitro. RESULTS: A total of 511 misaligned TFs were obtained and 200 GC-related TFs were exposed from them. After systematic analysis, a prognostic signature composed of 4 TFs (ZNF300, ELK3, SP6, MEF2B) were constructed. The KM and ROC curves demonstrated the good predictive ability in training, verification, and complete cohort. The areas under the ROC curve are respectively 0.737, 0.705, 0.700. The calibration chart verified that the predictive ability of the nomogram constructed by combining the prognostic signature of TFs and clinical information was accurate, with a C-index of 0.714. Enriching the target genes of hub TFs showed that it plays an vital role in tumor progression, and its expression and prognostic verification were consistent with the previous analysis. Among them, ELK3 was proved in vitro, and downregulation of its expression inhibited the proliferation of gastric cancer cells, induced proliferation, and exerted anti-tumor effects. CONCLUSIONS: The 4-TFs prognostic signature accurately predicted the overall survival of GC, and ELK3 may be potential therapeutic targets for GC.

ELK3: A New Molecular Marker for the Diagnosis and Prognosis of Glioma.

ETS transcription factor ELK3 (ELK3), a novel oncogene, affects pathological processes and progression of many cancers in human tissues. However, it remains unclear whether ELK3, as a key gene, affects the pathological process of gliomas and the prognosis of patients with gliomas. This study aimed to comprehensively and systematically reveal the correlation between ELK3 and the malignant progression of gliomas by analyzing clinical sample information stored in multiple databases. We revealed the putative mechanism of ELK3 involvement in malignant gliomas progression and identified a new and efficient biomarker for glioma diagnosis and targeted therapy. Based on the sample data from multiple databases and real-time quantitative polymerase chain reaction (RT-qPCR), the abnormally high expression of ELK3 in gliomas was confirmed. Kaplan-Meier and Cox regression analyses demonstrated that a high ELK3 expression was markedly associated with low patient survival and served as an independent biomarker of gliomas. Wilcox and Kruskal-Wallis tests revealed that expression of ELK3 was positively correlated with several clinical characteristics of patients with gliomas, such as age, WHO classification, and recurrence. Moreover, Cell Counting Kit-8 (CCK-8), immunofluorescence, and wound healing assays confirmed that ELK3 overexpression markedly promoted the proliferation and migration of glioma cells. Finally, gene set enrichment analysis (GSEA) and western blotting confirmed that overexpression of ELK3 regulated the JAK-STAT signaling pathway and upregulate the expression of signal transducer and activator of transcription 3 (STAT3) and phosphorylated STAT3 (P-STAT3) to promote the malignant transition of gliomas. Therefore, ELK3 may serve as an efficient biomarker for the diagnosis and prognosis of gliomas and it can also be used as a therapeutic target to improve the poor prognosis of patients with gliomas.

PIM1 inhibition attenuated endotoxin-induced acute lung injury through modulating ELK3/ICAM1 axis on pulmonary microvascular endothelial cells.

OBJECTIVE: The dysfunction of pulmonary microvascular endothelial cells (PMVECs) is one of the critical characteristics of acute lung injury/acute respiratory distress syndrome (ALI/ARDS) induced by severe infection. PIM1 is a constitutively active serine/threonine kinase that is involved in multiple biological processes. However, the underlying correlation between PIM1 and PMVECs injury remains unclear. The main purpose of this study was to reveal roles of PIM1 and explore the potential mechanisms during the development of endotoxin-induced ALI induced by intraperitoneal LPS administration. MATERIALS AND METHODS: PIM1 level in the lung tissues of endotoxin-induced ALI mice or plasma derived from cardiopulmonary bypass (CPB)-induced ALI patients were measured. The protective roles of PIM1 specific inhibitor SMI-4a on endotoxin-induced lung injuries were evaluated through histological, permeability, neutrophil infiltration and survival assessment. The relationship between PIM1 and ELK3/ICAM-1 axis was validated in vivo and vitro. The correlation between plasma PIM1 and indicative vascular endothelium injury biomarkers (PaO2/FiO2 ratio, Ang-II, E-selectin and PAI-1) levels derived from CPB-induced ALI patient were analyzed. RESULTS: PIM1 expression in the lung tissues was increased in the mice of endotoxin-induced ALI. The PIM1 specific inhibitor SMI-4a administration relieved the severity of endotoxin-induced ALI. More importantly, PIM1 modulates ICAM1 expression through regulating transcription factor ELK3 expression in vitro. Eventually, plasma PIM1 level was positively correlated with Ang-II and PAI-1 levels but negatively correlated with SpO2/FiO2 ratio among CPB induced ALI patients. CONCLUSION: Our results indicated that PIM1 inhibition carried a protective role against endotoxin-induced ALI by modulating the ELK3/ICAM1 axis on PMVECs. PIM1 may be a potential therapeutic target for endotoxin-induced ALI.

High ELK3 expression is associated with the VEGF-C/VEGFR-3 axis and gastric tumorigenesis and enhances infiltration of M2 macrophages.

Aim: To assess the expression and effect of ELK3 in gastric cancer, along with its associations with the VEGF-C/VEGFR-3 axis, IC50 of the VEGFR-3 inhibitor axitinib and immune infiltration of M2-polarized macrophages in gastric cancer, and to analyze the possible epigenetic regulation mechanism. Materials & methods: Expression profiles and methylation data from 1645 samples were obtained and examined from multi-institutional public datasets. The associations were assessed by multiple analysis methods. Results: Elevated ELK3 is associated with the VEGF-C/VEGFR-3 axis and tumorigenesis, reduces the effect of axitinib in vitro, enhances immune infiltration of M2 macrophages and affects clinical outcomes. Hypomethylation contributes to the upregulation of ELK3 in gastric cancer. Conclusions:ELK3 is a potential therapeutic target which reduces the effect of axitinib and enhances infiltration of M2-polarized macrophages.

Functional Link between miR-200a and ELK3 Regulates the Metastatic Nature of Breast Cancer.

Triple-negative breast cancer (TNBC) refers to breast cancer that does not have receptors for estrogen, progesterone, and HER2 protein. TNBC accounts for 10-20% of all cases of breast cancers and is characterized by its metastatic aggressiveness, poor prognosis, and limited treatment options. Here, we show that the metastatic nature of TNBC is critically regulated by a functional link between miR-200a and the transcription factor ELK3. We found that the expression levels of miR-200a and the ELK3 mRNA were negatively correlated in the luminal and TNBC subtypes of breast cancer cells. In vitro experiments revealed that miR-200a directly targets the 3' untranslated region (UTR) of the ELK3 mRNA to destabilize the transcripts. Furthermore, ectopic expression of miR-200a impaired the migration and invasion of TNBC cells by reducing the expression level of the ELK3 mRNA. In in vivo studies, transfection of MDA-MB 231 cells (a claudin-low TNBC cell type) with exogenous miR-200a reduced their extravasation into the lung during 48 h after tail vein injection, and co-transfection of the cells with an expression plasmid harboring ELK3 that lacked an intact 3'UTR recovered their extravasation ability. Overall, our findings provide evidences that miR-200a and ELK3 is functionally linked to regulate invasive characteristics of breast cancers.

SMAD3 promotes ELK3 expression following transforming growth factor ß-mediated stimulation of MDA-MB231 cells.

Transforming growth factor-ß (TGFß) is a secreted cytokine whose aberrant spatiotemporal expression is related to cancer progression and metastasis. While TGFß acts as a tumor suppressor in normal and premalignant stages, TGFß functions as a tumor promoter during the malignant phases of tumor progression by prompting cancer cells to undergo epithelial-mesenchymal transition (EMT), which enhances tumor cell invasion and ultimately promotes metastasis to other organs. Extensive studies have been performed to uncover the molecular and cellular mechanisms underlying TGFß inducing EMT in cancer cells. Here, we suggested that ELK3, which encodes a protein that orchestrates invasion and metastasis of triple negative breast cancer cells, is a downstream target of TGFß-SMAD3 in MDA-MB231 cells. ELK3 expression was increased in a time-dependent manner upon TGFß treatment. Chemical and molecular inhibition of the TGFß receptor blocked the ability of TGFß to induce ELK3 expression. Small interfering RNA-mediated suppression analysis revealed that SMAD3 induces TGFß signaling to express ELK3. Moreover, the results of the luciferase reporter assay and chromatin immunoprecipitation analysis showed that SMAD3 directly binds to the SMAD-binding element on the promoter of ELK3 to activate gene expression following TGFß stimulation. We concluded that ELK3 is a novel downstream target of TGFß-SMAD3 signaling in aggressive breast cancer cells.

Regulation of MicroRNA-155 and Its Related Genes Expression by Inositol Hexaphosphate in Colon Cancer Cells.

Inositol hexaphosphate (IP6), a natural dietary component, has been found as an antitumor agent by stimulating apoptosis and inhibiting cancer cell proliferation, their migration, and metastasis in diverse cancers including colon cancer. However, molecular mechanisms of its action have not been well understood. In recent years, microRNAs (miRNAs) have been reported to play important roles in a broad range of biologic processes, such as cell growth, proliferation, apoptosis, or autophagy. These small noncoding molecules regulate post-transcriptional expression of targets genes via degradation of transcript or inhibition of protein synthesis. Aberrant expression and/or dysregulation of miRNAs have been characterized during tumor development and progression, thus, they are potential molecular targets for cancer prevention. The aim of this study was to investigate the effect of IP6 on the miRNAs expression profile in Caco-2 colon cancer cells. 84 miRNAs were analyzed in Caco-2 cells treated with 2.5 mM and 5 mM IP6 by the use of PCR (Polymerase Chain Reaction) array. The effect of 5 mM IP6 on selected potential miR-155 targets was determined by real-time (RT)-qPCR and ELISA (quantitative Polymerase Chain Reaction and Enzyme-Linked Immunosorbent Assay )method. The results indicated alteration in the specific 10 miRNA expression in human colon cancer cells following their treatment with 5 mM IP6. It down-regulated 8 miRNAs (miR-155, miR-210, miR-144, miR-194, miR-26b, miR-126, miR-302c, and miR-29a) and up-regulated 2 miRNAs (miR-223 and miR-196b). In silico analysis revealed that FOXO3a, HIF-1α, and ELK3 mRNAs are those of predicted targets of miR-155. IP6 at the concentration of 5 mM markedly induced FOXO3a and HIF-1a genes' expression at both mRNA and protein level and decreased the amount of ELK3 mRNA as well as protein concentration in comparison to the control. In conclusion, the present study indicates that one of the mechanisms of antitumor potential of IP6 is down-regulation of the miR-155 expression in human colon cancer cells. Moreover, the expression of genes that are targeted by miRNA are also modulated by IP6.