ESE-1/ELF3 mRNA expression associates with poor survival outcomes in HER2+ breast cancer patients and is critical for tumorigenesis in HER2+ breast cancer cells

The function of the ELF3 gene and its mechanism in cancers

E74-like factor 3 (ELF3) is an important member of the E-twenty-six (ETS) transcription factor family. ELF3 is expressed in various types of cells and regulates a variety of biological behaviors, such as cell proliferation, differentiation, apoptosis, migration, and invasion, by binding to DNA to regulate the expression of other genes. In recent years, studies have shown that ELF3 plays an important role in the occurrence and development of many tumors and inflammation and immune related diseases. ELF3 has different functions and expression patterns in different tumors; it can function as a tumor suppressor gene or an oncogene, highlighting its dual effects of tumor promotion and inhibition. ELF3 also affects the levels of tumor immunity-related cytokines and is involved in the regulation and expression of multiple signaling pathways. In tumor therapy, ELF3 is a complex and multifunctional gene and has become a key focus of targeted treatment research. An in-depth study of the biological function of ELF3 can help to elucidate its role in biological processes and provide ideas and a basis for the development and clinical application of ELF3-related therapeutic methods. This review introduces the structure and physiological and cellular functions of the ELF3 gene, summarizes the mechanisms of action of ELF3 in different types of malignant tumors and its role in immune regulation, inflammation, etc., and discusses treatment methods for ELF3-related diseases, providing significant reference value for scholars studying the ELF3 gene and related diseases.

MicroRNAs as the critical regulators of epithelial mesenchymal transition in pancreatic tumor cells

Pancreatic cancer (PC), as one of the main endocrine and digestive systems malignancies has the highest cancer related mortality in the world. Lack of the evident clinical symptoms and appropriate diagnostic markers in the early stages of tumor progression are the main reasons of the high mortality rate among PC patients. Therefore, it is necessary to investigate the molecular pathways involved in the PC progression, in order to introduce novel early diagnostic methods. Epithelial mesenchymal transition (EMT) is a critical cellular process associated with pancreatic tumor cells invasion and distant metastasis. MicroRNAs (miRNAs) are also important regulators of EMT process. In the present review, we discussed the role of miRNAs in regulation of EMT process during PC progression. It has been reported that the miRNAs mainly regulate the EMT process in pancreatic tumor cells through the regulation of EMT-specific transcription factors and several signaling pathways such as WNT, NOTCH, TGF-β, JAK/STAT, and PI3K/AKT. Considering the high stability of miRNAs in body fluids and their role in regulation of EMT process, they can be introduced as the non-invasive diagnostic markers in the early stages of malignant pancreatic tumors. This review paves the way to introduce a non-invasive EMT based panel marker for the early tumor detection among PC patients.

Emerging role of miR-320a in lung cancer: a comprehensive review

A specialized biomarker(s) for lung cancer is imperative owing to its high mortality. Continuing our earlier work demonstrating the role of miR-320a as a tumor suppressor, here we discuss the most recent updates on miR-320a in lung cancer pathogenesis. We found that miR-320a modulates levels of diverse cancer-associated molecules and signaling pathways, and is also involved in modulating the immune microenvironment of lung cancer during its pathogenesis. We also discuss how miR-320a encapsulated in exosomes inhibits invasive phenotypes of lung cancer. Therefore, based on the multimodal role of miR-320a in lung cancer development and progression, we believe that miR-320a may be utilized as a potential diagnostic/prognostic marker and therapeutic target for lung cancer patients.

The ELF3 transcription factor is associated with an epithelial phenotype and represses epithelial-mesenchymal transition

BACKGROUND

Epithelial-mesenchymal plasticity (EMP) involves bidirectional transitions between epithelial, mesenchymal and multiple intermediary hybrid epithelial/mesenchymal phenotypes. While the process of epithelial-mesenchymal transition (EMT) and its associated transcription factors are well-characterised, the transcription factors that promote mesenchymal-epithelial transition (MET) and stabilise hybrid E/M phenotypes are less well understood.

RESULTS

Here, we analyse multiple publicly-available transcriptomic datasets at bulk and single-cell level and pinpoint ELF3 as a factor that is strongly associated with an epithelial phenotype and is inhibited during EMT. Using mechanism-based mathematical modelling, we also show that ELF3 inhibits the progression of EMT. This behaviour was also observed in the presence of an EMT inducing factor WT1. Our model predicts that the MET induction capacity of ELF3 is stronger than that of KLF4, but weaker than that of GRHL2. Finally, we show that ELF3 levels correlates with worse patient survival in a subset of solid tumour types.

CONCLUSION

ELF3 is shown to be inhibited during EMT progression and is also found to inhibit the progression of complete EMT suggesting that ELF3 may be able to counteract EMT induction, including in the presence of EMT-inducing factors, such as WT1. The analysis of patient survival data indicates that the prognostic capacity of ELF3 is specific to cell-of-origin or lineage.

ESE1/AGR2 axis antagonizes TGF-β-induced epithelial-mesenchymal transition in low-grade pancreatic cancer

Epithelium-specific ETS transcription factor 1 (ESE1) has been implicated in epithelial homeostasis, inflammation, as well as tumorigenesis, and cancer progression. However, numerous studies have reported contradictory roles-as an oncogene or a tumor suppressor of ESE1 in different cancers, and its function in the development and progression of pancreatic ductal adenocarcinoma (PDAC) has remained largely unexplored. Herein, we report that ESE1 was found upregulated in primary PDAC compared to normal pancreatic tissue, but high expression of ESE1 correlated to better relapse-free survival in patients with PDAC. Interestingly, ESE1 was found to exhibit dual roles in regulation of malignant properties of PDAC cells in that its overexpression promoted cell proliferation, whereas its downregulation enhanced epithelial-mesenchymal transition (EMT) phenotype. In the context of TGF-β-induced EMT, ESE1 is markedly downregulated at post-transcriptional level, and reconstituted ESE1 expression partially reversed TGF-β-induced EMT marker expression. Furthermore, we identify AGR2 as a novel transcriptional target of ESE1 that participates in TGF-β-induced EMT in PDAC. Collectively, our findings reveal an ESE1/AGR2 axis that interacts with TGF-β signaling to modulate EMT phenotype in PDAC.

Hypoxia‐induced ELF3 promotes tumor angiogenesis through IGF1/IGF1R

Epithelial ovarian cancer (EOC) is one of the most lethal gynecological cancers despite a relatively low incidence. Angiogenesis, one of the hallmarks of cancer, is essential for the pathogenesis of EOC, which is related to the induction of angiogenic factors. We found that ELF3 was highly expressed in EOCs under hypoxia and functioned as a transcription factor for IGF1. The ELF3‐mediated increase in the secretion of IGF1 and VEGF promoted endothelial cell proliferation, migration, and EOC angiogenesis. Although this situation was much exaggerated under hypoxia, ELF3 silencing under hypoxia significantly attenuated angiogenic activity in endothelial cells by reducing the expression and secretion of IGF1 and VEGF. ELF3 silencing attenuated angiogenesis and tumorigenesis in ex vivo and xenograft mouse models. Consequently, ELF3 plays an important role in the induction of angiogenesis and tumorigenesis in EOC as a transcription factor of IGF1. A detailed understanding of the biological mechanism of ELF3 may both improve current antiangiogenic therapies and have anticancer effects for EOC.

N6-Methyladenosine Regulators Are Involved in the Progression of and Have Clinical Impact on Breast Cancer

Background

N6-methyladenosine (m⁶A) modification has been widely studied in various cancers, and m⁶A regulators, such as METTL3, METTL14, WTAP, and YTHDF1, play crucial roles in breast cancer. However, a comprehensive study of m⁶A regulators in breast cancer is still lacking.

Material/Methods

Expression data of m⁶A regulators and clinicopathological information were acquired from The Cancer Genome Atlas (TCGA) program. Protein interaction was collected from the STRING database. Data on tumor purity and correlation among m⁶A regulators were obtained from the TIMER database. LASSO, consensus clustering, and gene set enrichment analysis (GSEA) were used to evaluate the role of m⁶A regulators. Moreover, the prognostic value of m⁶A-related genomic targets in breast cancer was analyzed by Kaplan-Meier analysis and Cox regression models.

Results

We found most m⁶A regulators were associated with key clinicopathological parameters, such as tumor staging, Nottingham prognostic index (NPI), and cellularity. Also, consensus clustering analysis-based grouping could effectively predict patients’ overall survival. Correlation analysis also showed that these regulators interacted with each other. Patients were further split into a high-risk group and low-risk group based on Cox and LASSO analysis. High-risk patients had a significantly worse overall survival than did low-risk patients. Moreover, AKT1 and MYC were enriched in patients in the high-risk group, according to GSEA analysis. The patients in the high-risk group also displayed resistance to chemoradiotherapy or hormone therapy.

Conclusions

The m⁶A regulators are critical participants in the development and progression of breast cancer and are likely to be used to predict prognosis and develop treatment strategies.

Nanopore Sequencing Unveils Diverse Transcript Variants of the Epithelial Cell-Specific Transcription Factor Elf-3 in Human Malignancies

The human E74-like ETS transcription factor 3 (Elf-3) is an epithelium-specific member of the ETS family, all members of which are characterized by a highly conserved DNA-binding domain. Elf-3 plays a crucial role in epithelial cell differentiation by participating in morphogenesis and terminal differentiation of the murine small intestinal epithelium, and also acts as an indispensable regulator of mesenchymal to epithelial transition, underlying its significant involvement in development and in pathological states, such as cancer. Although previous research works have deciphered the functional role of Elf-3 in normal physiology as well as in tumorigenesis, the present study highlights for the first time the wide spectrum of ELF3 mRNAs that are transcribed, providing an in-depth analysis of splicing events and exon/intron boundaries in a broad panel of human cell lines. The implementation of a versatile targeted nanopore sequencing approach led to the identification of 25 novel ELF3 mRNA transcript variants (ELF3 v.3–v.27) with new alternative splicing events, as well as two novel exons. Although the current study provides a qualitative transcriptional profile regarding ELF3, further studies must be conducted, so the biological function of all novel alternative transcript variants as well as the putative protein isoforms are elucidated.

ETS transcription factor ESE-1/Elf3 is an independent prognostic factor of survival in HR+HER2+ breast cancer patients

PURPOSE

The ETS transcription factor ESE-1 has been shown to be important in HER2⁺ breast cancer and ESE-1 mRNA expression has been shown to associate with prognostic outcomes in the HER2⁺ subtype, as well as in ER⁺, HER2⁺ luminal B patients. However, the clinical significance of ESE-1 protein expression remains unknown. The purpose of the current exploratory study is to evaluate the prognostic value of ESE-1 protein expression in molecular breast cancer subtypes with special emphasis on hormone receptor positive HER2⁺(HR⁺ HER2⁺) and the HER2 positive (HER2⁺-only) breast cancer patients.

METHODS

We developed a mouse monoclonal anti-ESE-1 antibody, verified its specificity, epitope, and used immunohistochemical staining to assess ESE-1 expression in an IBC approved archive of 957 breast tumor samples. Using Pearson product correlation, contingency analysis, and long rank P value testing, we analyzed the association of ESE-1 expression with clinicopathological features and survival outcomes in HR⁺HER2^-; HR⁺HER2⁺; HR^- HER2^- (Triple negative) and HR^-HER2⁺ (HER2 subtype) patients.

RESULTS

ESE-1, nuclear or cytoplasmic, was not significantly associated with survival outcomes in HR⁺HER2^-, triple-negative, or HER2⁺-only breast cancer patients. However, high nuclear ESE-1 was associated with poor survival outcomes in hormone receptor positive (ERα⁺, PR⁺) HER2⁺ patients and was an independent prognostic marker for that group.

CONCLUSIONS

This study provides evidence for prognostic significance of nuclear ESE-1 in ERalpha positive breast cancers patients also positive for HER2 indicating that crosstalk between ERalpha and ESE-1 in HER2⁺ tumors could be important for prognostic outcomes. Further studies regarding the nature of interaction between ESE-1 and ERalpha in these tumors are warranted.

The miR-1224-5p/ELF3 Axis Regulates Malignant Behaviors of Pancreatic Cancer via PI3K/AKT/Notch Signaling Pathways

Purpose

Aberrant expression of microRNAs contributes to the progression of pancreatic cancer by targeting downstream genes. A novel regulatory axis, miR-1224-5p/ELF3, was identified by bioinformatic analysis and experimental verification. Studies of the underlying molecular mechanisms behind this axis lead to a better understanding of the development of pancreatic cancer.

Materials and Methods

The differential expression of miR-1224-5p and ELF3 was verified based on Gene Expression Omnibus (GEO) datasets and clinical samples. The relationship between miR-1224-5p and ELF3 was demonstrated by luciferase assay and Western blot. The related signaling pathways of the miR-1224-5p/ELF3 axis in pancreatic cancer were investigated by gene set enrichment analysis (GSEA) and verified by Western blot. An analysis between ELF3 expression and immune infiltration was performed. Cellular and animal experiments were utilized to explore the effects of miR-1224-5p and ELF3 in pancreatic cancer.

Results

Suppressed expression of miR-1224-5p in pancreatic tumor tissues and cancer cells was identified first. Furthermore, miR-1224-5p is correlated with clinicopathological features, and decreased expression of miR-1224-5p indicates poor prognosis. miR-1224-5p serves as a tumor suppressor and inhibits malignant behaviors of pancreatic cancer based on in vivo and in vitro assays. The putative target gene ELF3 was predicted by bioinformatic analysis and confirmed by dual-luciferase reporter assay. Overexpression of ELF3 can improve the malignant behaviors of pancreatic cancer and demonstrates poor prognosis and advanced clinical stage. The inhibitory role of miR-1224-5p in pancreatic cancer is manifested by its direct targeting of ELF3. A negative correlation between ELF3 expression and immune cell infiltration was identified, suggesting an immunosuppressive state resulting from ELF3 overexpression. The PI3K/AKT/Notch signaling pathways and epithelial-to-mesenchymal transition (EMT) are important underlying mechanisms.

Conclusion

The miR-1224-5p/ELF3 axis may serve as a new diagnostic, therapeutic, and prognostic biomarker in pancreatic cancer. The related PI3K/AKT/Notch/EMT signaling pathways greatly promote the elucidation of the progression of pancreatic cancer.

Targeting PDZ-binding kinase is anti-tumorigenic in novel preclinical models of ACC

Adrenocortical carcinoma (ACC) is an aggressive orphan malignancy with less than 35% 5-year survival and 75% recurrence. Surgery remains the primary therapy and mitotane, an adrenolytic, is the only FDA-approved drug with wide-range toxicities and poor tolerability. There are no targeted agents available to date. For the last three decades, H295R cell line and its xenograft were the only available preclinical models. We recently developed two new ACC patient-derived xenograft mouse models and corresponding cell lines (CU-ACC1 and CU-ACC2) to advance research in the field. Here, we have utilized these novel models along with H295R cells to establish the mitotic PDZ-binding kinase (PBK) as a promising therapeutic target. PBK is overexpressed in ACC samples and correlates with poor survival. We show that PBK is regulated by FOXM1 and targeting PBK via shRNA decreased cell proliferation, clonogenicity and anchorage-independent growth in ACC cell lines. PBK silencing inhibited pAkt, pp38MAPK and pHistone H3 altering the cell cycle. Therapeutically, targeting PBK with the small-molecule inhibitor HITOPK032 phenocopied PBK-specific modulation of pAkt and pHistone H3, but also induced apoptosis via activation of JNK. Consistent with in vitro findings, treatment of CU-ACC1 PDXs with HITOPK032 significantly reduced tumor growth by 5-fold (P < 0.01). Treated tumor tissues demonstrated increased rates of apoptosis and JNK activation, with decreased pAkt and Histone H3 phosphorylation, consistent with effects observed in ACC cell lines. Together these studies elucidate the mechanism of PBK in ACC tumorigenesis and establish the potential therapeutic potential of HITOPK032 in ACC patients.

Ultrasound-mediated delivery of siESE complexed with microbubbles attenuates HER2+/- cell line proliferation and tumor growth in rodent models of breast cancer

The highly tunable, noninvasive and spatially targeted nature of microbubble-enhanced, ultrasound-guided (MB+US) drug delivery makes it desirable for a wide variety of therapies. In breast cancer, both HER2+ and HER2- type neoplasms pose significant challenges to conventional therapeutics in greater than 40% of breast cancer patients, even with the widespread application of biologics such as trastuzumab. To address this therapeutic challenge, we examined the novel combination of tumor-injected microbubble-bound siRNA complexes and monodisperse size-isolated microbubbles (4-µm diameter) to attenuate tumor growth in vivo, as well as MB+US-facilitated shRNA and siRNA knockdown of ESE-1, an effector linked to dysregulated HER2 expression in HER2+/- cell line propagation. We first screened six variants of siESE and shESE for efficient knockdown of ESE in breast cancer cell lines. We demonstrated efficient reduction of BT-474 (PR+, ER+, HER2+; luminal B) and MDA-MB-468 (PR-, ER-, HER2-; triple-negative) clonogenicity and non-adherent growth after knockdown of ESE-1. A significant reduction in proliferative potential was seen for both cell lines using MB+US to deliver shESE and siESE. We then demonstrated significant attenuation of BT-474 xenograft tumor growth in Nod/SCID female mice using direct injection of microbubble-adsorbed siESE to the tumor and subsequent sonication. Our results suggest a positive effect on drug delivery from MB+US, and highlights the feasibility of using RNAi and MB+US for breast cancer pathologies. RNAi coupled with MB+US may also be an effective theranostic approach to treat other acoustically accessible tumors, such as melanoma, thyroid, parotid and skin cancer.

ELF3, ELF5, EHF and SPDEF Transcription Factors in Tissue Homeostasis and Cancer

The epithelium-specific ETS (ESE) transcription factors (ELF3, ELF5, EHF and SPDEF) are defined by their highly conserved ETS DNA binding domain and predominant epithelial-specific expression profile. ESE transcription factors maintain normal cell homeostasis and differentiation of a number of epithelial tissues, and their genetic alteration and deregulated expression has been linked to the progression of several epithelial cancers. Herein we review the normal function of the ESE transcription factors, the mechanisms by which they are dysregulated in cancers, and the current evidence for their role in cancer progression. Finally, we discuss potential therapeutic strategies for targeting or reactivating these factors as a novel means of cancer treatment.

MiR-320a-3p/ELF3 axis regulates cell metastasis and invasion in non-small cell lung cancer via PI3K/Akt pathway

MicroRNAs (miRNAs) play important roles in tumorigenesis and tumor progression. In this study, we investigated the role of miR-320a-3p in non-small cell lung cancer (NSCLC). Expressions of miR-320a-3p were firstly determined in 80 NSCLC patients' cancer tissues and adjacent normal lung tissues by qRT-PCR. Then MTT assay, cell migration and invasion assays were performed in vitro. Potential binding sites on target gene of miR-320a-3p were predicted and luciferase reporter assay was used to identify the potential binding sites. Tumorigenesis assay were performed in nude mice by injecting A549 cells which stably express miR-320a-3p. Results indicated that high expression of miR-320a-3p suppresses cell proliferation, migration and invasion through the inactivation of PI3K/Akt signaling pathway in NSCLC cells. Smaller tumor size and lighter weight were also found in nude mice which had miR-320a-3p higher expressed. Furthermore, data from luciferase reporter assay proved the direct binding of miR-320a-3p on the 3'UTR region of ELF3 mRNA, this could further decrease ELF3 expression transcriptionally. We provided evidence that miR-320a-3p might work as a tumor suppressor in NSCLC both in vivo and in vitro.