ETV4 Facilitates Cell-Cycle Progression in Pancreatic Cells through Transcriptional Regulation of Cyclin D1

ETV4 promotes the progression of cholangiocarcinoma by regulating glycolysis via the TGF-β signaling

BACKGROUND

Considerable studies show that ETS variant 4 (ETV4) plays an important roles in multitudinous tumor. This study investigated its function in cholangiocarcinoma (CCA) progression and revealed the underlying mechanisms.

METHODS

The expression of ETV4 in CCA was evaluated using TCGA database and the single-cell analysis based on GSE189903 dataset. ETV4 expression in CCA human specimens was detected by reverse transcription-quantitative PCR, immunohistochemistry, and western blot. Cell Counting Kit-8, EdU, colony formation, wound healing, and Transwell assays were used to analyze the effects of ETV4. Extracellular acidification rate, oxygen consumption rate, glucose uptake, and lactate production were used to measure glycolysis in CAA cells. Western blot was performed to explore glycolysis-related proteins. Tumor growth was evaluated in mice xenograft tumors.

RESULTS

ETV4 was up-regulated in CCA epithelial cells. The high-expression of ETV4 was associated with poor prognosis of patients with CCA. ETV4 overexpression enhanced the proliferation, migration, invasion, and glycolysis of CCA cells; ETV4 silencing led to the contrary effects. Mechanistically, ETV4 activates TGF-β/Smad2/3 signaling pathway. In mice xenograft mode, ETV4 silencing inhibits the tumor growth, the expression of glycolysis-related proteins and TGF-β/Smad2/3 pathway proteins.

CONCLUSIONS

ETV4 functions as an essential factor in the roles of TGF-β1 in CCA cells, and may be a promising target for TGF-β1-mediated CCA progression.

Biological effect of ETV4 and the underlying mechanism of its regulatory effect on epithelial‑mesenchymal transition in intrahepatic cholangiocarcinoma cells

Intrahepatic cholangiocarcinoma (ICC) is a highly invasive malignant tumor. The prognosis of patients with ICC after radical surgical resection remains poor, due to local infiltration, distant metastasis, a high recurrence rate and lack of effective treatment strategies. E26 transformation-specific sequence variant 4 (ETV4) is a pro-carcinogenic factor that is upregulated in several tumors; however, the role of ETV4 in ICC is relatively unknown. The present study aimed to determine the role of ETV4 in the Hccc9810 ICC cell line and to assess how it contributes to epithelial-mesenchymal transition (EMT) in ICC. Hccc9810 cells were infected with lentiviruses to construct stable ETV4-overexpressing cells, stable ETV4 knockdown cells and corresponding control groups. The Cell Counting Kit-8 and Transwell assays were used to quantify cell proliferation, invasion and migration, and the effects on cell cycle progression and apoptosis were detected by flow cytometry. ETV4 was identified as a driver of cell growth, invasion, migration and cell cycle progression, while restraining apoptosis in Hccc9810 cells. Reverse transcription-quantitative PCR and western blotting revealed that increased ETV4 levels may drive EMT by triggering the TGF-β1/Smad signaling pathway. This cascade, in turn, may foster tumor cell proliferation, migration, invasion and cell cycle advancement, and hinder apoptosis.

An oncogenic enhancer promotes melanoma progression via regulating ETV4 expression

BACKGROUND

Enhancers are important gene regulatory elements that promote the expression of critical genes in development and disease. Aberrant enhancer can modulate cancer risk and activate oncogenes that lead to the occurrence of various cancers. However, the underlying mechanism of most enhancers in cancer remains unclear. Here, we aim to explore the function and mechanism of a crucial enhancer in melanoma.

METHODS

Multi-omics data were applied to identify an enhancer (enh17) involved in melanoma progression. To evaluate the function of enh17, CRISPR/Cas9 technology were applied to knockout enh17 in melanoma cell line A375. RNA-seq, ChIP-seq and Hi-C data analysis integrated with luciferase reporter assay were performed to identify the potential target gene of enh17. Functional experiments were conducted to further validate the function of the target gene ETV4. Multi-omics data integrated with CUT&Tag sequencing were performed to validate the binding profile of the inferred transcription factor STAT3.

RESULTS

An enhancer, named enh17 here, was found to be aberrantly activated and involved in melanoma progression. CRISPR/Cas9-mediated deletion of enh17 inhibited cell proliferation, migration, and tumor growth of melanoma both in vitro and in vivo. Mechanistically, we identified ETV4 as a target gene regulated by enh17, and functional experiments further support ETV4 as a target gene that is involved in cancer-associated phenotypes. In addition, STAT3 acts as a transcription factor binding with enh17 to regulate the transcription of ETV4.

CONCLUSIONS

Our findings revealed that enh17 plays an oncogenic role and promotes tumor progression in melanoma, and its transcriptional regulatory mechanisms were fully elucidated, which may open a promising window for melanoma prevention and treatment.

ETV4 facilitates proliferation, migration, and invasion of liver cancer by mediating TGF-β signal transduction through activation of B3GNT3

BACKGROUND

Metastasis of liver cancer (LC) is the main cause of its high mortality. ETV4 is a critical regulatory factor in promoting LC progression, but the mechanism that ETV4 impacts LC proliferation, migration, and invasion is poorly understood.

OBJECTIVE

Investigation of the molecular mechanism of LC metastasis is conducive to developing effective drugs that prevent LC metastasis.

METHODS

Expression of ETV4 and its target gene B3GNT3 in LC tissue was analyzed by bioinformatics, and the result was further verified in LC cells by qRT-PCR. In vitro cellular assays evaluated the impact of ETV4 on the proliferation, migration, and invasion of LC cells. Chromatin immunoprecipitation (ChIP) and dual-luciferase reporter gene assay were conducted to analyze the interaction between B3GNT3 and ETV4. SB525334 suppressor was used to treat and access the activation of ETV4 on the TGF-β pathway.

RESULTS

We discovered that ETV4 and B3GNT3 were evidently up-regulated in LC, and high expression of ETV4 was coupled to the increase of proliferation, migration, and invasion of LC cells and epithelial-mesenchymal transition ability. Besides, ETV4 could bind to the B3GNT3 promoter and activate its transcription. Knockdown of B3GNT3 could prominently suppress the effect of up-regulated ETV4 on LC cells. Meanwhile, ETV4 could activate the TGF-β signaling pathway via B3GNT3, while SB525334 treatment notably repressed the functions of ETV4.

CONCLUSION

ETV4 emerges as a driven oncogene in LC, and the ETV4/B3GNT3-TGF-β pathway promotes proliferation, migration, invasion, and epithelial-mesenchymal transition progress of LC. Inhibition of the pathway may provide an underlying method for the prevention and treatment of LC metastasis.

Differential expression of PEA3 in odontogenic cysts and tumors

BACKGROUND

PEA3 transcription factor has been identified as a downstream target of the MAPK and PI3K pathways, and PEA3 overexpression has been observed in a variety of tumor types. We aimed to evaluate PEA3 expression in odontogenic cysts and tumors and compare the expression among odontogenic lesions. In addition, the correlations between PEA3 expression and clinicopathological characteristics of conventional ameloblastoma and unicystic ameloblastoma were investigated.

METHODS

This study was performed on 165 samples of odontogenic cysts and tumors including 20 dentigerous cysts, 20 odontogenic keratocysts, 16 adenomatoid odontogenic tumors, 5 ameloblastic fibromas, 45 unicystic ameloblastomas, and 59 conventional ameloblastomas. The sections were immunohistochemically stained with mouse monoclonal anti-PEA3 antibody and PEA3 expression was evaluated as the immunoreactive score.

RESULTS

PEA3 expression was absent in all dentigerous cysts (DCs) and odontogenic keratocysts, while all adenomatoid odontogenic tumors showed either no (75%) or low (25%) expression of PEA3. Most of the ameloblastic fibromas (60%) displayed no PEA3 expression. A high expression of PEA3 was observed in a substantial number of unicystic ameloblastomas (48.9%) and conventional ameloblastomas (49.2%) in our study. PEA3 expression in DCs, odontogenic keratocysts and adenomatoid odontogenic tumors were significantly different from that in conventional ameloblastomas and that in unicystic ameloblastomas (p < 0.05). The expression of PEA3 was significantly different in the age groups of unicystic ameloblastomas and histological subtypes of conventional ameloblastomas (p < 0.05).

CONCLUSION

PEA3 overexpression is predominant in unicystic ameloblastomas and conventional ameloblastomas compared to other odontogenic lesions, indicating a pivotal role of PEA3 as a downstream effector of MAPK pathway in these two odontogenic lesions.

Targeting PEA3 transcription factors to mitigate small cell lung cancer progression

Small cell lung cancer (SCLC) remains a lethal disease with a dismal overall survival rate of 6% despite promising responses to upfront combination chemotherapy. The key drivers of such rapid mortality include early metastatic dissemination in the natural course of the disease and the near guaranteed emergence of chemoresistant disease. Here, we found that we could model the regression and relapse seen in clinical SCLC in vitro. We utilized time-course resolved RNA-sequencing to globally profile transcriptome changes as SCLC cells responded to a combination of cisplatin and etoposide-the standard-of-care in SCLC. Comparisons across time points demonstrated a distinct transient transcriptional state resembling embryonic diapause. Differential gene expression analysis revealed that expression of the PEA3 transcription factors ETV4 and ETV5 were transiently upregulated in the surviving fraction of cells which we determined to be necessary for efficient clonogenic expansion following chemotherapy. The FGFR-PEA3 signaling axis guided the identification of a pan-FGFR inhibitor demonstrating in vitro and in vivo efficacy in delaying progression following combination chemotherapy, observed inhibition of phosphorylation of the FGFR adaptor FRS2 and corresponding downstream MAPK and PI3K-Akt signaling pathways. Taken together, these data nominate PEA3 transcription factors as key mediators of relapse progression in SCLC and identify a clinically actionable small molecule candidate for delaying relapse of SCLC.

Down-regulated MiRNA 29-b as a diagnostic marker in colorectal cancer and its correlation with ETV4 and Cyclin D1 immunohistochemical expression

BACKGROUND

Colorectal cancer (CRC) is the most common malignant tumor of the gastrointestinal tract with unfavorable prognosis. Therefore, novel biomarkers that may be used for new diagnostic strategies and drug-targeting therapy should be developed.

OBJECTIVES

To investigate the expression of miR-29b in CRC and its association with ETV4 and cyclin D1 expression. Moreover, the current work aims to investigate the association between them and the clinicopathological features of CRC.

METHODS

The expression of miR-29b and ETV4 (by qRT-PCR) and ETV4 and cyclin D1 (immunohistochemistry) was investigated in 65 cases of colon cancer and surrounding healthy tissues.

RESULTS

MiR-29b down-regulated and ETV4 and Cyclin D1 up-regulated significantly in colon cancer tissues compared to normal nearby colonic tissues. In addition, significant associations between ETV4 and cyclin D1 expressions and progressive stage and lymph node (LN) metastasis (P< 0.001 for each) were found. Furthermore, there was a negative correlation between miR-29b gene expression and ETV4 gene expression (r=-0.298, P<0.016).

CONCLUSION

Down-regulation of miR-29b and over-expression of ETV4 and cyclin D1 may be utilized as early diagnostic marker for development of colon cancer. ETV4 and cyclin D1 correlate with poor prognostic indicators and considered as a possible target for therapy in colon cancer.

Dissecting novel mechanisms of hepatitis B virus related hepatocellular carcinoma using meta-analysis of public data

BACKGROUND

Hepatitis B virus (HBV) is a cause of hepatocellular carcinoma (HCC). Interestingly, this process is not necessarily mediated through cirrhosis and may in fact involve oncogenic processes. Prior studies have suggested specific oncogenic gene expression pathways were affected by viral regulatory proteins. Thus, identifying these genes and associated pathways could highlight predictive factors for HCC transformation and has implications in early diagnosis and treatment.

AIM

To elucidate HBV oncogenesis in HCC and identify potential therapeutic targets.

METHODS

We employed our Search, Tag, Analyze, Resource platform to conduct a meta-analysis of public data from National Center for Biotechnology Information’s Gene Expression Omnibus. We performed meta-analysis consisting of 155 tumor samples compared against 185 adjacent non-tumor samples and analyzed results with ingenuity pathway analysis.

RESULTS

Our analysis revealed liver X receptors/retinoid X receptor (RXR) activation and farnesoid X receptor/RXR activation as top canonical pathways amongst others. Top upstream regulators identified included the Ras family gene rab-like protein 6 (RABL6). The role of RABL6 in oncogenesis is beginning to unfold but its specific role in HBV-related HCC remains undefined. Our causal analysis suggests RABL6 mediates pathogenesis of HBV-related HCC through promotion of genes related to cell division, epigenetic regulation, and Akt signaling. We conducted survival analysis that demonstrated increased mortality with higher RABL6 expression. Additionally, homeobox A10 (HOXA10) was a top upstream regulator and was strongly upregulated in our analysis. HOXA10 has recently been demonstrated to contribute to HCC pathogenesis in vitro. Our causal analysis suggests an in vivo role through downregulation of tumor suppressors and other mechanisms.

CONCLUSION

This meta-analysis describes possible roles of RABL6 and HOXA10 in the pathogenesis of HBV-related HCC. RABL6 and HOXA10 represent potential therapeutic targets and warrant further investigation.

Identification of potential plasma protein biomarkers for feline pancreatic carcinoma by liquid chromatography tandem mass spectrometry

In both humans and cats, pancreatic carcinoma is an aggressive cancer with a grave prognosis. Proteomics techniques have successfully identified several blood-based biomarkers of human pancreatic neoplasia. Thus, this study aims to investigate whether similar biomarkers can be identified in the plasma of cats with FePAC by using liquid chromatography tandem mass spectrometry (LC-MS/MS). To facilitate evaluation of the low abundance plasma proteome, a human-based immunodepletion device (MARS-2) was first validated for use with feline plasma. Marked reduction and/or complete removal of albumin and immunoglobulins was confirmed by analysis of electrophoretograms and mass spectral data. Subsequently, plasma collected from 9 cats with pancreatic carcinoma (FePAC), 10 cats with symptomatic pancreatitis, and 10 healthy control cats was immunodepleted and subjected to LC-MS/MS. Thirty-seven plasma proteins were found to be differentially expressed (p < .05 in one-way ANOVA, FC >2 in fold change analysis). Among these proteins, ETS variant transcription factor 4 (p < .05) was overexpressed, while gelsolin (p < .01), tryptophan 2,3-dioxygenase (p < .05), serpin family F member 1 (p < .01), apolipoprotein A-IV (p < .01) and phosphatidylinositol-glycan-specific phospholipase D (p < .05) were down-regulated in cats with FePAC. Further studies on these potential biomarkers are needed to investigate their diagnostic value.

Reliable epithelial-mesenchymal transition biomarkers for colorectal cancer detection

Aims: To combat increases in colorectal cancer (CRC) incidence and mortality, biomarkers among differentially expressed genes (DEGs) have been identified to objectively detect cancer. However, DEGs are numerous, and additional parameters may identify more reliable biomarkers. Here, CRC DEGs were filtered into a prioritized list of biomarkers. Materials & methods: Two independent datasets (COAD-READ [n = 698] and GSE50760 [n = 36]) were input alternatively to the recently published data-driven reference method. Results were filtered based on epithelial-mesenchymal transition enrichment (χ-square statistic: 919.05; p = 2.2e-16) to produce 37 potential CRC biomarkers. Results: All 37 genes reliably classified CRC samples and ETV4, CLDN1 and CA2 together were top-ranked by DDR (accuracy: 89%; F1 score: 0.89). Conclusion: Biological and statistical information were combined to produce a better set of CRC detection biomarkers.

Pathological and Prognostic Characterization of Craniopharyngioma Based on the Expression of TrkA, β-Catenin, Cell Cycle Markers, and BRAF V600E Mutation

We collected 61 craniopharyngioma (CP) specimens to investigate the expression of TrkA, β-catenin, BRAF gene mutation, and NTRK1 fusion in CP. There were 37 male and 24 female individuals with a median age of 34 years (range, 4-75 years). Histologically, there were 46 cases of adamantinomatous craniopharyngioma (ACP), 14 cases of papillary craniopharyngioma (PCP), and 1 case with a mixed adamantinomatous and papillary pattern. By immunohistochemistry, we found that moderate/high TrkA expression was detected in 47% (28/60) CP and was significantly higher in adult patients (p = 0.018). Interestingly, TrkA is more expressed in "whorled epithelium" cells in ACP, similar to the localization of abnormal β-catenin. The abnormal expression rate of β-catenin was 70% (43/61), and the medium/high cyclin D1 expression rate was 73% (44/60), both of which were significantly higher in ACP than in PCP. Of the CP, 41% (21/51) had a moderate/strong P16-positive signal; 58% (34/59) showed a high Ki-67 expression, and there was a significant correlation between high Ki-67 L.I. and high tumor recurrence (p = 0.021). NTRK1 fusion was not found in CP by fluorescence in situ hybridization (FISH). By PCR, 26% (15/58) CP showed BRAF V600E gene mutation, which mainly occurred in PCP (100%, 14/14) except one case of mixed CP. Moreover, TrkA expression was negatively correlated with Ki-67 index and positively correlated with P16 expression. There was a significantly negative correlation between BRAF V600E mutation and abnormal β-catenin expression. Our results demonstrate for the first time that TrkA expression might occur in CP, especially in adult CP patients, and suggest that cyclin D1 could be used for ACP histological classification in addition to β-catenin and BRAF V600E mutation, while Ki-67 could be used as a marker to predict CP recurrence.

ETV4 promotes pancreatic ductal adenocarcinoma metastasis through activation of the CXCL13/CXCR5 signaling axis

Pancreatic ductal adenocarcinoma (PDAC) has the highest fatality rate of any solid tumor, with a five-year survival rate of only 10% in the USA. PDAC is characterized by early metastasis. More than 50% of patients present with distant metastases at the time of diagnosis, and the majority of patients will develop metastasis within 4 years after tumor resection. Despite extensive studies, the molecular mechanisms underlying PDAC metastasis remain unclear. The polyoma enhancer activator protein (PEA3) subfamily was reported to play a vital role in the initiation and progression of multiple tumors. Herein, we found that ETS variant 4 (ETV4) was highly expressed in PDAC tissues and associated with poor survival. Univariate and multivariate analyses revealed that ETV4 expression was an independent prognostic factor for patient survival. Further experiments showed that ETV4 overexpression promoted PDAC invasion and metastasis both in vitro and in vivo. For the first time, we demonstrated that, mechanistically, ETV4 increased CXCR5 expression by directly binding to the CXCR5 promoter region. Knockdown of CXCR5 significantly reversed ETV4-mediated PDAC migration and invasion, while CXCR5 overexpression exerted the opposite effects. Intriguingly, we found that CXCL13, a specific ligand of CXCR5, increased ETV4 expression and promoted PDAC invasion and metastasis by activating the ERK1/2 pathway. ETV4 knockdown significantly abrogated the enhanced migratory and invasive abilities induced by the CXCL13/CXCR5 axis. In addition, a CXCR5 neutralizing antibody disrupted the CXCL13/ETV4/CXCR5 positive feedback loop and inhibited cell migration and invasion. Overall, in this study, we demonstrated that ETV4 plays a vital role in PDAC metastasis and defined a novel CXCL13/ETV4/CXCR5 positive feedback loop. Targeting this pathway has implications for potential therapeutic strategies for PDAC treatment.

Tumor-associated macrophages (TAMs) depend on MMP1 for their cancer-promoting role

The complex interaction between tumor-associated macrophages (TAMs) and tumor cells through several soluble factors and signaling is essential for colorectal cancer (CRC) progression. However, the molecular mechanism involved remains elusive. In this study, we demonstrated that MMP1 derived from TAMs markedly facilitated colon cancer cell proliferation via accelerating cell cycle transition from G0/G1 to S and G2/M phase. Moreover, exogenous MMP1 activated cdc25a/CDK4-cyclin D1 and p21/cdc2-cyclin B1 complexes through altering c-Myc and ETV4. Mechanistic studies indicated that inhibition of PAR1 or blockage of MAPK/Erk signaling eliminated the proliferation induced by exogenous MMP1 in vitro and in vivo. In addition, ETV4 could bind to the promoter of MMP1 and activate MMP1 transcription, which confirmed the MMP1/ETV4/MMP1 positive feedback. Altogether, our study identified a cytokine paracrine manner between colon cancer cells and TAMs. MMP1/PAR1/Erk1/2/ETV4 positive feedback loop may represent to be a therapeutic target and prognostic marker in CRC.

E26 transformation-specific variant 4 as a tumor promotor in human cancers through specific molecular mechanisms

E26 transformation-specific (ETS) variant 4 (ETV4) is an important transcription factor that belongs to the ETS transcription factor family and is essential for much cellular physiology. Recent evidence has revealed that ETV4 is aberrantly expressed in many types of tumors, and its overexpression is related to poor prognosis of cancer patients. Additionally, increasing studies have identified that ETV4 promotes cancer growth, invasion, metastasis, and drug resistance. Mechanistically, the level of ETV4 is regulated by some post-translation modulations in a broad spectrum of cancers. However, little progress has been made to comprehensively summarize the critical roles of ETV4 in different human cancers. Hence, this review mainly focuses on the physiological functions of ETV4 in various human tumors. In addition, the molecular mechanisms of ETV4-mediated cancer progression were elucidated, including how ETV4 modulates its downstream signaling pathways and how ETV4 is regulated by some factors. On this basis, the present review may provide a valuable therapeutics strategy for future cancer treatment by targeting ETV4-related pathways.

ETV4 mediates the wnt/β-catenin pathway through transcriptional activation of ANXA2 to promote hepatitis B virus-associated liver hepatocellular carcinoma progression

ETS variant 4 (ETV4) has been implicated in the development of various cancers. However, the molecular events mediated by ETV4 in liver cancer are poorly understood, especially in Hepatitis B virus (HBV)-associated liver hepatocellular carcinoma (LIHC). Here, we aimed to identify the target involved in ETV4-driven hepatocarcinogenesis. Bioinformatics analysis revealed that ETV4 was highly expressed in patients with HBV-associated LIHC, and HBV infection promoted the expression of ETV4 in LIHC cells. Inhibition of ETV4 repressed the proliferation, migration, invasion of LIHC cells and suppressed the secretion of HBV and the replication of HBV DNA. ANXA2 expression in LIHC patients was positively correlated with ETV4 expression. ChIP and dual-luciferase reporter assays revealed that ETV4 elevated the ANXA2 expression at the transcriptional level by binding to the ANXA2 promoter. Overexpression of ANXA2 reversed the inhibitory effect of sh-ETV4 on the malignant biological behaviors of HBV-infected LIHC cells by activating the Wnt/β-catenin pathway. In conclusion, ETV4 mediates the activation of Wnt/β-catenin pathway through transcriptional activation of ANXA2 expression to promote HBV-associated LIHC progression.

ETV4 transcriptionally activates HES1 and promotes Stat3 phosphorylation to promote malignant behaviors of colon adenocarcinoma

Colon adenocarcinoma (COAD) is the commonest type of colorectal cancer with high morbidity and mortality worldwide. ETS variant 4 (ETV4) is a member of the ETS transcription factors and is frequently involved in the progression of many cancers. This study focused on the relevance of ETV4 to the progression of COAD. ETV4 was highly expressed in the collected COAD tissues and acquired cells and indicated advanced Dukes staging in patients. Knockdown of ETV4 in COAD cells weakened proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) activity of cells. The downstream genes of ETV4 were predicted, and a Gene Ontology (GO) analysis was conducted to identify the key molecule involved. ETV4 bound to the promoter sequence of HES1 and activated its transcription. Further overexpression of HES1 restored the malignant behaviors of COAD cells. HES1 was also found to promote phosphorylation of Stat3. Similar results were reproduced in vivo where downregulation of ETV4 blocked the growth of xenograft tumors in nude mice. This study demonstrated that ETV4 encourages malignant development of COAD through activating HES1 transcription and Stat3 phosphorylation. This study may offer novel insights into COAD therapy.

ETV4 and ETV5 drive synovial sarcoma through cell cycle and DUX4 embryonic pathway control

Synovial sarcoma is an aggressive malignancy with no effective treatments for patients with metastasis. The synovial sarcoma fusion SS18-SSX, which recruits the SWI/SNF-BAF chromatin remodeling and polycomb repressive complexes, results in epigenetic activation of FGF receptor (FGFR) signaling. In genetic FGFR-knockout models, culture, and xenograft synovial sarcoma models treated with the FGFR inhibitor BGJ398, we show that FGFR1, FGFR2, and FGFR3 were crucial for tumor growth. Transcriptome analyses of BGJ398-treated cells and histological and expression analyses of mouse and human synovial sarcoma tumors revealed prevalent expression of two ETS factors and FGFR targets, ETV4 and ETV5. We further demonstrate that ETV4 and ETV5 acted as drivers of synovial sarcoma growth, most likely through control of the cell cycle. Upon ETV4 and ETV5 knockdown, we observed a striking upregulation of DUX4 and its transcriptional targets that activate the zygotic genome and drive the atrophy program in facioscapulohumeral dystrophy patients. In addition to demonstrating the importance of inhibiting all three FGFRs, the current findings reveal potential nodes of attack for the cancer with the discovery of ETV4 and ETV5 as appropriate biomarkers and molecular targets, and activation of the embryonic DUX4 pathway as a promising approach to block synovial sarcoma tumors.

Circular RNA hsa_circ_0001666 sponges miR‑330‑5p, miR‑193a‑5p and miR‑326, and promotes papillary thyroid carcinoma progression via upregulation of ETV4

Circular RNAs (circRNAs) are a group of regulators that affect the aggressive behaviors of several types of cancer. Hsa_circ_0001666 (also referred to as hsa_circ_000742) is a newly discovered circRNA that is upregulated in human papillary thyroid carcinoma (PTC) based on microarray analysis. However, the role of hsa_circ_0001666 in PTC progression remains unknown. Thus, the aim of the present study was to determine the potential function and underlying mechanism of hsa_circ_0001666 in PTC. The results demonstrated that hsa_circ_0001666 was upregulated in both PTC clinical samples and cell lines. Its expression was associated with lymph node metastasis of patients with PTC. Knocking down hsa_circ_0001666 expression inhibited cell proliferation, as evidenced by decreased cell viability, arrest of cell cycle progression at the G₁ phase and an increase in cell cycle-associated proteins. Apoptosis rates and expression levels of pro-apoptotic proteins were also increased by silencing hsa_circ_0001666. In xenograft experiments, the oncogenic effect of hsa_circ_0001666 on tumor growth was verified. Additionally, luciferase reporter assays showed that hsa_circ_0001666 and ETS variant transcription factor 4 (ETV4) shared common binding sites with three microRNAs [(miRNA/miR)-330-5p, miR-193a-5p and miR-326]. Knockdown of these miRNAs separately reversed the inhibitory effect of hsa_circ_0001666 small interfering RNAs on PTC tumor aggressiveness, and ETV4 overexpression also induced a similar effect to that of miRNA inhibitors. Thus, hsa_circ_0001666 may function as an oncogene, promoting PTC tumorigenesis via the miR-330-5p/miR-193a-5p/miR-326/ETV4 pathway. This provides a basis for identifying potential novel therapeutic targets for PTC.

Acetylation of ELF5 suppresses breast cancer progression by promoting its degradation and targeting CCND1

E74-like ETS transcription factor 5 (ELF5) is involved in a wide spectrum of biological processes, e.g., mammogenesis and tumor progression. We have identified a list of p300-interacting proteins in human breast cancer cells. Among these, ELF5 was found to interact with p300 via acetylation, and the potential acetylation sites were identified as K130, K134, K143, K197, K228, and K245. Furthermore, an ELF5-specific deacetylase, SIRT6, was also identified. Acetylation of ELF5 promoted its ubiquitination and degradation, but was also essential for its antiproliferative effect against breast cancer, as overexpression of wild-type ELF5 and sustained acetylation-mimicking ELF5 mutant could inhibit the expression of its target gene CCND1. Taken together, the results demonstrated a novel regulation of ELF5 as well as shedding light on its important role in modulation of breast cancer progression.

Molecular profiles of response to neoadjuvant chemoradiotherapy in oesophageal cancers to develop personalized treatment strategies

Identification of molecular predictive markers of response to neoadjuvant chemoradiation could aid clinical decision‐making in patients with localized oesophageal cancer. Therefore, we subjected pretreatment biopsies of 75 adenocarcinoma (OAC) and 16 squamous cell carcinoma (OSCC) patients to targeted next‐generation DNA sequencing, as well as biopsies of 85 OAC and 20 OSCC patients to promoter methylation analysis of eight GI‐specific genes, and subsequently searched for associations with histopathological response and disease‐free (DFS) and overall survival (OS). Thereby, we found that in OAC, CSMD1 deletion (8%) and ETV4 amplification (5%) were associated with a favourable histopathological response, whereas SMURF1 amplification (5%) and SMARCA4 mutation (7%) were associated with an unfavourable histopathological response. KRAS (15%) and GATA4 (7%) amplification were associated with shorter OS. In OSCC, TP63 amplification (25%) and TFPI2 (10%) gene promoter methylation were associated with an unfavourable histopathological response and shorter DFS (TP63) and OS (TFPI2), whereas CDKN2A deletion (38%) was associated with prolonged OS. In conclusion, this study identified candidate genetic biomarkers associated with response to neoadjuvant chemoradiotherapy in patients with localized oesophageal cancer.

Roquin1 inhibits the proliferation of breast cancer cells by inducing G1/S cell cycle arrest via selectively destabilizing the mRNAs of cell cycle-promoting genes

BACKGROUND

Dysregulation of cell cycle progression is a common feature of human cancer cells; however, its mechanism remains unclear. This study aims to clarify the role and the underlying mechanisms of Roquin1 in cell cycle arrest in breast cancer.

METHODS

Public cancer databases were analyzed to identify the expression pattern of Roquin1 in human breast cancers and its association with patient survival. Quantitative real-time PCR and Western blots were performed to detect the expression of Roquin1 in breast cancer samples and cell lines. Cell counting, MTT assays, flow cytometry, and in vivo analyses were conducted to investigate the effects of Roquin1 on cell proliferation, cell cycle progression and tumor progression. RNA sequencing was applied to identify the differentially expressed genes regulated by Roquin1. RNA immunoprecipitation assay, luciferase reporter assay, mRNA half-life detection, RNA affinity binding assay, and RIP-ChIP were used to explore the molecular mechanisms of Roquin1.

RESULTS

We showed that Roquin1 expression in breast cancer tissues and cell lines was inhibited, and the reduction in Roquin1 expression was associated with poor overall survival and relapse-free survival of patients with breast cancer. Roquin1 overexpression inhibited cell proliferation and induced G1/S cell cycle arrest without causing significant apoptosis. In contrast, knockdown of Roquin1 promoted cell growth and cycle progression. Moreover, in vivo induction of Roquin1 by adenovirus significantly suppressed breast tumor growth and metastasis. Mechanistically, Roquin1 selectively destabilizes cell cycle-promoting genes, including Cyclin D1, Cyclin E1, cyclin dependent kinase 6 (CDK6) and minichromosome maintenance 2 (MCM2), by targeting the stem-loop structure in the 3' untranslated region (3'UTR) of mRNAs via its ROQ domain, leading to the downregulation of cell cycle-promoting mRNAs.

CONCLUSIONS

Our findings demonstrated that Roquin1 is a novel breast tumor suppressor and could induce G1/S cell cycle arrest by selectively downregulating the expression of cell cycle-promoting genes, which might be a potential molecular target for breast cancer treatment.

Impact of Capicua on Pancreatic Cancer Progression

BACKGROUND

The transcription factor capicua (CIC) regulates mammalian development and homeostasis. Growing evidence shows that CIC suppresses various human cancers by directly repressing the downstream cancer-related target genes. This study investigated the clinical and biologic significance of CIC expression in pancreatic cancer (PC).

METHODS

The study reviewed 132 patients with PC who underwent curative resection. The patients were divided into two groups according to CIC immunoreactivity score by immunohistochemistry, and the associations between CIC expression, clinicopathologic characteristics, and postoperative prognosis were investigated. Moreover, the influence of CIC expression on the malignant potential of PC cells was assessed with cell proliferation, motility assays, and use of quantitative real time-polymerase chain reaction and Western blot on the downstream target genes of CIC in knockdown experiments.

RESULTS

The low-CIC expression group showed a higher proportion of lymphatic invasion (72.9% vs. 53.1%; p = 0.024), intrapancreatic neural invasion (94.1% vs. 81.3%; p = 0.021), and extrapancreatic plexus invasion (30.9% vs. 7.8%; p = 0.0006) than the high-CIC expression group as well as significantly worse overall survival (p = 0.0002) and recurrence-free survival (p = 0.0041) rates. Low CIC expression was an independent risk factor for poor prognosis (p = 0.038). Pancreatic cancer cells with knockdown CIC significantly enhanced cell motilities and cell cycle progression, promoted expression levels of ETV4 and MMP-9, and induced EMT.

CONCLUSIONS

The study elucidated the association of low CIC expression with a poor prognosis for patients with PC and suggested that the CIC-ETV4-MMP-9 axis might control PC progression.

Function and regulation of the PEA3 subfamily of ETS transcription factors in cancer

The PEA3 subfamily is a subgroup of the E26 transformation-specific (ETS) family. Its members, ETV1, ETV4, and ETV5, have been found to be overexpressed in multiple cancers. The deregulation of ETV1, ETV4, and ETV5 induces cell growth, invasion, and migration in various tumor cells, leading to tumor progression, metastasis, and drug resistance. Therefore, exploring drugs or therapeutic targets that target the PEA3 subfamily may contribute to the clinical treatment of tumor patients. In this review, we introduce the structures and functions of the PEA3 subfamily members, systematically review their main roles in various tumor cells, analyze their prognostic and diagnostic value, and, finally, introduce several molecular targets and therapeutic drugs targeting ETV1, ETV4, and ETV5. We conclude that targeting a series of upstream regulators and downstream target genes of the PEA3 subfamily may be an effective strategy for the treatment of ETV1/ETV4/ETV5-overexpressing tumors.

Melatonin modulates proliferation of pancreatic stellate cells through caspase-3 activation and changes in cyclin A and D expression

In this study, the effects of melatonin (1 μM-1 mM) on pancreatic stellate cells (PSC) have been examined. Cell viability and proliferation, caspase-3 activation, and the expression of cyclin A and cyclin D were analyzed. Our results show that melatonin decreased PSC viability in a time- and concentration-dependent manner. This effect was not inhibited by treatment of cells with MT1, MT2, calmodulin, or ROR-alpha inhibitors prior to melatonin addition. Activation of caspase-3 in response to melatonin was detected. The expression of cyclin A and cyclin D was decreased in cells treated with melatonin. Finally, changes in BrdU incorporation into the newly synthesized DNA of proliferating cells were also observed in the presence of melatonin. We conclude that melatonin, at pharmacological concentrations, modulates proliferation of PSC through activation of apoptosis and involving crucial regulators of the cell cycle. These actions might not require specific melatonin receptors. Our observations suggest that melatonin, at high doses, could potentially exert anti-fibrotic effects and, thus, could be taken into consideration as supportive treatment in the therapy of pancreatic diseases.

Knockdown of P3H4 inhibits proliferation and invasion of bladder cancer

The prolyl 3-hydroxylase family member 4 (P3H4) (alias SC65) is implicated in a variety of physiological and pathological processes. However, little is known about the role of P3H4 in tumors. This study aimed to investigate the role of P3H4 in bladder cancer (BC) and the regulatory mechanisms that influence its expression. P3H4 was highly expressed in BC tissues. Knockdown of P3H4 inhibited BC cell proliferation, cell cycle, migration and invasion in vitro, and inhibited BC growth in vivo. We also found that ETV4 bound directly to the promoter region of P3H4 and activated its transcription. Furthermore, overexpression of ETV4 rescued the inhibition of proliferation and invasion induced by PH4 silencing. ETV4 was significantly overexpressed in the BC tissues. In conclusion, P3H4 functioned an oncogene role in BC progression, and ETV4 bound directly to the P3H4 promoter region to regulate its transcription.

ETV4 overexpression promotes progression of non-small cell lung cancer by upregulating PXN and MMP1 transcriptionally

ETS variant 4 (ETV4), together with ETV1 and ETV5, constitute the PEA3 subfamily of ETS transcription factors, which are implicated in the progression of many cancers. However, the clinicopathologic significance and molecular events regulated by ETV4 in lung cancer are still poorly understood, especially in squamous cell carcinoma of the lung. Here, we aimed to identify functional targets involved in ETV4-driven lung tumorigenesis. Microarray analysis and validation data revealed that ETV4 was the most preponderant PEA3 factor, which was significantly related to the advanced stage, lymph node metastasis, and poor prognosis of non-small cell lung cancers (NSCLCs; all P < .001). Reduced ETV4 expression suppressed the growth and metastasis of NSCLC both in vivo and in vitro. Microarray, gain, or loss of function and luciferase report assays revealed the direct regulatory effect of ETV4 on the expression of focal adhesion gene PXN and matrix metalloproteinase 1 (MMP1), and PXN and/or MMP1 inhibition partially abolished cell proliferation and migration induced by ETV4. Kaplan-Meier analysis indicated that ETV4 and PXN or MMP1 co-overexpression is associated with poor prognosis in human NSCLCs. In conclusion, the ETV4-PXN and ETV4-MMP1 axes are useful biomarkers of tumor progression and worse outcomes in NSCLCs.

NeTFactor, a framework for identifying transcriptional regulators of gene expression-based biomarkers

Biological and regulatory mechanisms underlying many multi-gene expression-based disease biomarkers are often not readily evident. We describe an innovative framework, NeTFactor, that combines network analyses with gene expression data to identify transcription factors (TFs) that significantly and maximally regulate such a biomarker. NeTFactor uses a computationally-inferred context-specific gene regulatory network and applies topological, statistical, and optimization methods to identify regulator TFs. Application of NeTFactor to a multi-gene expression-based asthma biomarker identified ETS translocation variant 4 (ETV4) and peroxisome proliferator-activated receptor gamma (PPARG) as the biomarker's most significant TF regulators. siRNA-based knock down of these TFs in an airway epithelial cell line model demonstrated significant reduction of cytokine expression relevant to asthma, validating NeTFactor's top-scoring findings. While PPARG has been associated with airway inflammation, ETV4 has not yet been implicated in asthma, thus indicating the possibility of novel, disease-relevant discovery by NeTFactor. We also show that NeTFactor's results are robust when the gene regulatory network and biomarker are derived from independent data. Additionally, our application of NeTFactor to a different disease biomarker identified TF regulators of interest. These results illustrate that the application of NeTFactor to multi-gene expression-based biomarkers could yield valuable insights into regulatory mechanisms and biological processes underlying disease.

[E26 transformation-specific variant 4 promotes sorafenib and cisplatin resistance in hepatocellular carcinoma cells in vitro]

OBJECTIVE

To investigate the role of E26 transformation-specific variant 4 (ETV4) in sorafenib and cisplatin resistance in hepatocellular carcinoma (HCC).

METHODS

HCC cell lines SMMC-7721 and HCC-LM3 were transfected with an ETV4- overexpressing plasmid or small interfering RNAs (siRNAs) targeting ETV4. The cells with ETV4 overexpression or ETV4 interference were treated with DMSO, sorafenib (5 μmol/L) or cisplatin (5 μmol/L) for 48 h, and the total protein and total RNA were collected. Western blotting, flow cytometry, EdU proliferation assay were used to analyze the apoptosis and proliferation of the cells. We also obtained clinical specimens of HCC tissues and paired adjacent tissues from 11 patients for detecting ETV4 mRNA expression levels using real-time fluorescence quantitative PCR (q-PCR). The effect of ETV4 interference on the mRNA expression levels of immediate early response gene 3 (IER3) was examined in HCC cells that were treated with DMSO, sorafenib or cisplatin for 48 h.

RESULTS

The expression of ETV4 mRNA was significantly higher in HCC tissues than in the paired adjacent tissues. Overexpression of ETV4 in the HCC cell lines obviously inhibited cell apoptosis induced by sorafenib or cisplatin. Conversely, ETV4 interference significantly enhanced the apoptosis and inhibited the proliferation of the HCC cells following treatments with sorafenib or cisplatin. In addition, ETV4 regulated the mRNA expression levels of IER3 in the cells treatmed with sorafenib and cisplatin.

CONCLUSIONS

ETV4 promotes resistance of HCC cells to sorafenib or cisplatin in vitro.

ETS transcription factors as emerging drug targets in cancer

The ETS family of proteins consists of 28 transcription factors, many of which have been implicated in development and progression of a variety of cancers. While one family member, ERG, has been rigorously studied in the context of prostate cancer where it plays a critical role, other ETS factors keep emerging as potential hallmark oncodrivers. In recent years, numerous studies have reported initial discoveries of small molecule inhibitors of ETS proteins and opened novel avenues for ETS-directed cancer therapies. This review summarizes the state of the art data on therapeutic targeting of ETS family members and highlights the corresponding drug discovery strategies.

Caveolin-1 and -2 regulate cell motility in castration-resistant prostate cancer

Background

Caveolin (Cav)-1 and Cav-2 are cell membrane proteins, which are structural proteins of caveolae and are reported to be positive regulators of cell survival and metastasis in prostate cancer (PC). In a previous study, we reported that elevated levels of Cav-1 and Cav-2 were significantly associated with PC progression. However, their functions in PC have not yet been clarified. In this study, we examined the function of Cav-1 and Cav-2 in PC cell invasiveness and motility.

Materials and methods

We introduced Cav-1- and Cav-2-specific small interfering into PC3 cells to knock-down (KD) both molecules. We also performed cell proliferation assay, wound healing assay, migration assay, and invasion assay using PC3 cells and compared the results between Cav-1-KD, Cav-2-KD, and negative control PC3 cells. In addition, we performed real-time quantitative PCR (RT-qPCR) and RT2 Profiler PCR Array analysis to identify factors influencing migration.

Results

We observed no significant difference in the proliferative and invasive activities of Cav-1-KD and Cav-2-KD PC3 cells; however, the cell motility was significantly decreased compared with negative control PC3 cells. RT-qPCR revealed that the expression of vimentin and N-cadherin was downregulated in Cav-1-KD PC3 cells. In addition, PCR array revealed a decreased expression of MGAT5, MMP13, and MYCL in Cav-1-KD PC3 and ETV4, FGFR4, and SRC in Cav-2-KD PC3.

Conclusion

Cav-1 and Cav-2 may positively contribute to the upregulation of castration-resistant PC cell migration. Cav-induced regulation of several molecules including vimentin, N-cadherin, MGAT5, MMP13, MYCL, ETV4, FGFR4, and SRC may have an important role in PC3 cell motility. However, further examination will be required.

Long noncoding RNA SNHG6 promotes osteosarcoma cell proliferation through regulating p21 and KLF2

The effects of long non-coding RNAs (lncRNAs) on cellular biological processes and even the tumorigenesis have been widely reported. Small nucleolar RNA host gene 6 (SNHG6) has been reported to participate in regulating biological behaviors of multiple types of cancers. Nevertheless, the functions of SNHG6 in osteosarcoma still remain to be uncovered. This study intended to determine the clinical significance and biological functions of SNHG6 in osteosarcoma. It was confirmed by qRT-PCR that SNHG6 was highly expressed in osteosarcoma tissues and cell lines. Highly expressed SNHG6 predicted poor survival rate and advanced clinical stage for osteosarcoma patients, according to Kaplan-Meier method and Cox regression analysis. Loss-of-function assays were performed to examine the effects of silenced SNHG6 on the progression of osteosarcoma, indicating that silenced SNHG6 suppressed cell proliferation through inducing cell cycle arrest in G0/G1 phase and causing cell apoptosis. In vitro assays exposed the potential oncogenic role of SNHG6 in osteosarcoma, further affirmed by in vivo nude mice assays. Mechanistic assays demonstrated that SNHG6 was negatively correlated with p21 and KLF2 in osteosarcoma. And biological functions of SNHG6 in osteosarcoma were realized through regulating p21 and KLF2. Collectively, SNHG6 was a new type of molecule involving in the progression of osteosarcoma.