Prognostic values of E2F mRNA expression in human gastric cancer

Comprehensive review regarding the association of E2Fs with the prognosis and immune infiltrates in human head and neck squamous cell carcinoma

E2F transcription factors (E2Fs) are a group of genes that encode a family of transcription factors. They have been identified as being involved in the tumor progression of various cancer types. However, little is known about the expression level, genetic variation, molecular mechanism, and prognostic value and immune infiltration of different E2Fs in HNSCC.In this study, we utilized multiple databases to investigate the mRNA expression level, genetic alteration, and biological function of E2Fs in HNSCC patients. Then, the relationship between E2Fs expression and its association with the occurrence, progress, prognosis, and immune cell infiltration in patients with HNSCC was evaluated. We found that all eight E2Fs were higher expressed in HNSCC tissues than in normal tissues, and the expression levels of E2F1/2/3/4/5/6/8 were also associated with the stage and grade of HNSCC. The abnormal expression of E2F1/2/4/8 in HNSCC patients is related to the clinical outcome. The expression of E2Fs was statistically correlated with the immune cell infiltration in HNSCC and the infiltration of B cells and CD8+ T cells were positively associated with better OS in HNSCC patients. Furthermore, we verified the E2F2 at the tissue level in the validation experiment. Our study may provide novel insights into the choice of immunotherapy targets and potential prognostic biomarkers in HNSCC patients.

Expression patterns of E2Fs identify tumor microenvironment features in human gastric cancer

Objective

E2F transcription factors are associated with tumor development, but their underlying mechanisms in gastric cancer (GC) remain unclear. This study explored whether E2Fs determine the prognosis or immune and therapy responses of GC patients.

Methods

E2F regulation patterns from The Cancer Genome Atlas (TCGA) were systematically investigated and E2F patterns were correlated with the characteristics of cellular infiltration in the tumor microenvironment (TME). A principal component analysis was used to construct an E2F scoring model based on prognosis-related differential genes to quantify the E2F regulation of a single tumor. This scoring model was then tested in patient cohorts to predict effects of immunotherapy.

Results

Based on the expression profiles of E2F transcription factors in GC, two different regulatory patterns of E2F were identified. TME and survival differences emerged between the two clusters. Lower survival rates in the Cluster2 group were attributed to limited immune function due to stromal activation. The E2F scoring model was then constructed based on the E2F-related prognostic genes. Evidence supported the E2F score as an independent and effective prognostic factor and predictor of immunotherapy response. A gene-set analysis correlated E2F score with the characteristics of immune cell infiltration within the TME. The immunotherapy cohort database showed that patients with a higher E2F score demonstrated better survival and immune responses.

Conclusions

This study found that differences in GC prognosis might be related to the E2F patterns in the TME. The E2F scoring system developed in this study has practical value as a predictor of survival and treatment response in GC patients.

miR-125b-5p, miR-155-3p, and miR-214-5p and Target E2F2 Gene in Oral Squamous Cell Carcinoma

It is known that E2F2 (E2F transcription factor 2) plays an important role as controller in the cell cycle. This study aimed to analyse the expression of the E2F2 gene and E2F2 protein and demonstrate E2F2 target microRNAs (miRNAs) candidates (miR-125b-5p, miR-155-3p, and miR-214-5p) in oral squamous cell carcinoma tumour and margin samples. The study group consisted 50 patients. The E2F2 gene and miRNAs expression levels were assessed by qPCR, while the E2F2 protein was assessed by ELISA. When analysing the effect of miRNAs expression on E2F2 gene expression and E2F2 protein level, we observed no statistically significant correlations. miR-125b-5p was downregulated, while miR-155-3p, and miR-214-5p were upregulated in tumour samples compared to margin. We observed a difference between the miR-125b-5p expression level in smokers and non-smokers in margin samples. Furthermore, HPV-positive individuals had a significantly higher miR-125b-5p and miR-214-5p expression level compared to HPV-negative patients in tumour samples. The study result showed that the E2F2 gene is not the target for analysed miRNAs in OSCC. Moreover, miR-155-3p and miR-125b-5p could play roles in the pathogenesis of OSCC. A differential expression of the analysed miRNAs was observed in response to tobacco smoke and HPV status.

Dexmedetomidine promotes ferroptotic cell death in gastric cancer via hsa_circ_0008035/miR-302a/E2F7 axis

Dexmedetomidine (DEX), a common anesthetic, has significant effects on the biological features of cancer cells. Although numerous studies have been published on the impact of DEX on the biological characteristics of GC cells, the mechanism remains unknown. This study aimed to explore the effect of DEX on the biological properties of GC cells. DEX suppressed the viability and increased the apoptosis of GC cells in vitro and inhibited tumor growth in vivo. Besides, DEX raised the levels of reactive oxygen species (ROS) and iron, but decreased the levels of glutathione (GSH), glutathione peroxidase 4 (GPX4), and solute carrier family 7 member 11 (SLC7A11) in GC cells, which were abolished by Ferrostatin-1 (the inhibitor of ferroptosis) treatment. In addition, the level of circ0008035 and E2F7 were downregulated, but miR-302a level was upregulated in DEX-treated GC cells. Circ0008035 increased the expression of E2F2 by acting as a sponge for miR-302a. Circ0008035 inhibited DEX-induced ferroptotic cell death in GC cells, which was reversed by miR-302a overexpression or E2F7 reduction. Taken together, DEX mediated ferroptotic cell death in GC through regulating the circ0008035/miR-302a/E2F7 axis, suggesting a feasible therapy option for GC.

A bioinformatics analysis for diagnostic roles of the E2F family in esophageal cancer

BACKGROUND

Esophageal cancer (EC) is the eighth most commonly occurring cancer worldwide and the sixth leading cause of cancer-related deaths. The therapeutic effect of EC patients is not ideal, and new biomarkers are needed to guide diagnosis and prognosis of EC patients. E2F family transcription factors are among the most important links in the cell cycle regulatory network. E2Fs dysregulation not only promotes the early stages of tumor development but also the progression of benign tumors to malignant tumors. E2F is expected to be a new biomarker. The prognostic significance of the E2F family in EC requires further research.

METHODS

We analyzed The Cancer Genome Atlas (TCGA), Gene Expression Profiling Interactive Analysis (GEPIA), and GeneMANIA databases to obtain RNA-sequencing data and clinical data. The clinical data included age, gender, race, stage, type, status, etc. The prognosis outcome included overall survival (OS) and progression-free interval (PFI). Subsequently, we conducted further research on gene expressions, enrichment analysis, interaction network, and prognostic values by R software, containing ggplot2, ComplexHeatmap, DESeq2, pROC R package, based on t-test, Wilcoxon rank sum test, Spearman rank correlation analysis, log-rank test and COX model.

RESULTS

We found that mRNA transcription levels of E2F1, E2F3-8 were more highly expressed in esophageal carcinoma (ESCA) tissues than in normal tissues. E2F8 expression was correlated with tumor stage [Pr(>F)=0.00856]. E2F-related genes played a role in development and differentiation, and were prevalent in the endoplasmic reticulum lumen, Golgi lumen, and lipoprotein particle, catalyzing translation activities and lipid metabolism. Each gene was found to be related to each other to some degree. The GeneMANIA network analysis revealed links between E2Fs and other genes. We compared the correlations between 24 kinds of tumor-infiltrating immune cells and E2Fs. E2F1 (AUC =0.945, CI: 0.890-1.000) and E2F7 (AUC =0.958, CI: 0.920-0.996) exhibited higher predictive power accuracy. However, only E2F7 was closely related to OS [HR =1.91 (1.16-3.16), P=0.011].

CONCLUSIONS

We discover that E2F7 is a prognostic biomarker. E2F family may take part in the development of EC through lipid metabolism pathways, which is helpful to predict the prognosis of EC patients and guide accurate diagnosis and treatment.

PLK2 Single Nucleotide Variant in Gastric Cancer Patients Affects miR-23b-5p Binding

PURPOSE

Chromosomal instability is a hallmark of gastric cancer (GC). It can be driven by single nucleotide variants (SNVs) in cell cycle genes. We investigated the associations between SNVs in candidate genes, PLK2, PLK3, and ATM, and GC risk and clinicopathological features.

MATERIALS AND METHODS

The genotyping study included 542 patients with GC and healthy controls. Generalized linear models were used for the risk and clinicopathological association analyses. Survival analysis was performed using the Kaplan-Meier method. The binding of candidate miRs was analyzed using a luciferase reporter assay.

RESULTS

The PLK2 Crs15009-Crs963615 haplotype was under-represented in the GC group compared to that in the control group (Pcorr=0.050). Male patients with the PLK2 rs963615 CT genotype had a lower risk of GC, whereas female patients had a higher risk (P=0.023; P=0.026). The PLK2 rs963615 CT genotype was associated with the absence of vascular invasion (P=0.012). The PLK3 rs12404160 AA genotype was associated with a higher risk of GC in the male population (P=0.015). The ATM Trs228589-Ars189037-Grs4585 haplotype was associated with a higher risk of GC (P<0.001). The ATM rs228589, rs189037, and rs4585 genotypes TA+AA, AG+GG, and TG+GG were associated with the absence of perineural invasion (P=0.034). In vitro analysis showed that the cancer-associated miR-23b-5p mimic specifically bound to the PLK2 rs15009 G allele (P=0.0097). Moreover, low miR-23b expression predicted longer 10-year survival (P=0.0066) in patients with GC.

CONCLUSIONS

PLK2, PLK3, and ATM SNVs could potentially be helpful for the prediction of GC risk and clinicopathological features. PLK2 rs15009 affects the binding of miR-23b-5p. MiR-23b-5p expression status could serve as a prognostic marker for survival in patients with GC.

E2F4 transcription factor is a prognostic biomarker related to immune infiltration of head and neck squamous cell carcinoma

To investigate the relationship between the transcription factor, E2F4, and head and neck squamous cell carcinoma (HNSCC), and to preliminarily explore the signaling pathways and immunological role of E2F4. The mRNA expression of E2F4 in HNSCC was evaluated by searching Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) datasets. E2F4 protein expression was analyzed by immunohistochemistry using the CMU1h-ENT database. The association between E2F4 expression and tumor infiltration of immune cells was analyzed. Intracellular signaling by E2F4 was explored using KEGG and GO analysis. The correlation of E2F4 expression with clinical characteristics and its prognostic role were validated and analyzed in TCGA database. From the analysis of GEO and TCGA data, E2F4 expression was found to be up-regulated in HNSCC tumor tissues, and its level was associated with T, Grade, and M staging. Kaplan–Meier curve and Cox analyses indicated that the high expression of E2F4 was related to a poor prognosis. Thus, E2F4 was considered a potential prognostic factor for HNSCC. Immunohistochemical staining showed that E2F4 was mainly localized in the cell nucleus; it was highly expressed in HNSCC tissues, with a significant difference noted from that in pericancerous mucosa tissues. A correlation was observed between the differential expression of E2F4 and the immune infiltration of HNSCC. As revealed by KEGG and GO analysis, differential enrichment was found in the cell cycle, spliceosome, meiosis, microbial polysaccharide synthesis, and WNT signaling pathway, as well as in cyclic adenosine monophosphate, ERBB2, VEGF, GCNP and MYC pathways. E2F4 plays an important role in tumor progression and may be a critical biological prognostic factor for HNSCC. In addition, it functions in the nucleus as a transcription factor, regulates immune cells, and could be a promising molecular target for the diagnosis and treatment of HNSCC.

A novel circ_0000654/miR-375/E2F3 ceRNA network in esophageal squamous cell carcinoma

Background

The competing endogenous RNA (ceRNA) activity of circular RNAs (circRNAs) has been implicated in the pathogenesis of cancers, including esophageal squamous cell carcinoma (ESCC). Here, we identified the ceRNA mechanism of circ_0000654 regulation in ESCC.

Methods

The levels of circ_0000654, E2F transcription factor 3 (E2F3), and microRNA (miR)‐375 were gauged by quantitative real‐time PCR (qRT‐PCR) and western blot. Cell proliferation was assessed by 3‐(4,5‐dimethylthiazol‐2‐yl)‐5‐(3‐carboxymethoxyphenyl)‐2‐(4‐sulfophenyl)‐2H‐tetrazolium (MTS) and 5‐ethynyl‐2′‐deoxyuridine (EdU) assays. Cell apoptosis was detected by flow cytometry. Cell colony formation was tested by colony formation assay. Dual‐luciferase reporter, RNA pull‐down and RNA immunoprecipitation (RIP) assays were performed to confirm the direct relationship between miR‐375 and circ_0000654 or E2F3. Xenograft model assays were used to evaluate the effect of circ_0000654 in vivo.

Results

Circ_0000654 and E2F3 were upregulated in ESCC. Circ_0000654 depletion enhanced cell apoptosis and hindered cell proliferation and glycolysis in vitro, as well as weakened tumor growth in vivo. Increased expression of E2F3 counteracted the effects of circ_0000654 depletion. Mechanistically, E2F3 was a target of miR‐375, and circ_0000654 modulated E2F3 expression through sequestering miR‐375. Furthermore, miR‐375 upregulation phenocopied circ_0000654 knockdown in inhibiting ESCC progression.

Conclusion

Our findings identify a new circ_0000654/miR‐375/E2F3 ceRNA crosstalk for the oncogenic role of circ_0000654 in ESCC and establish a notion that targeting circ_0000654 and its pathways may have the potential to improve ESCC outcome.

E2F4-induced AGAP2-AS1 up-regulation accelerates the progression of colorectal cancer via miR-182-5p/CFL1 axis

BACKGROUND

Long non-coding RNAs (lncRNAs) are closely associated with the pathogenesis of numerous diseases including cancers. LncRNA AGAP2 Antisense RNA 1 (AGAP2-AS1) has been found to participate in the tumorigenesis of several kinds of human cancers. Nonetheless, its potential function in colorectal cancer (CRC) was still poorly investigated.

METHODS

The expression level of RNAs or proteins was assessed by RT-qPCR or western blot analysis. Functional experiments were performed to analyze the role of AGAP2-AS1 in CRC in vitro and in vivo. Mechanism investigations were fulfilled to determine the potential mechanism of the molecules.

RESULTS

AGAP2-AS1 expression was significantly elevated in CRC cells and could be transcriptionally activated by E2F Transcription Factor 4 (E2F4). Down-regulated AGAP2-AS1 could weaken CRC cell growth, migration, invasion, and epithelial-mesenchymal transition (EMT). MicroRNA-182-5p (miR-182-5p) was the target downstream molecule of AGAP2-AS1. Furthermore, Cofilin 1 (CFL1) was proved as the target of miR-182-5p. Mechanically, AGAP2-AS1 could boost the CFL1 expression via competitively binding to miR-182-5p in CRC. Importantly, CFL1 restoration could counteract the in vitro and in vivo suppression of depleted AGAP2-AS1 on CRC progression.

CONCLUSION

E2F4-stimulated AGAP2-AS1 aggravated CRC development through regulating miR-182-5p/CFL1 axis, implying that AGAP2-AS1 might become a potent new target for future therapies for CRC.

E2F5 promotes proliferation and invasion of gastric cancer through directly upregulating UBE2T transcription

The underlying mechanisms of E2F5 upregulation and its pro-tumor functions have not been elucidated in gastric cancer (GC). Here, the expression, prognostic value, mutation status, and promoter methylation of E2F5 were evaluated. The effects of E2F5 depletion on cell proliferation and invasion in GC, were also assessed through in vitro experiments. Additionally, gene set enrichment analysis (GSEA) was applied to analyze the potential downstream regulator of E2F5. The study also assessed the correlation and transcription regulation between E2F5 and UBE2T. Finally, the roles of UBE2T in E2F5-related pro-tumor functions were examined. The findings revealed that E2F5 was upregulated and showed remarkable association with pathological variables and prognosis. Hypomethylation of the E2F5 promoter predicted poor prognosis and partially caused E2F5 upregulation in GC. E2F5 knockdown significantly inhibited the proliferation and invasion of GC cells. E2F5 had a significant positive correlation with UBE2T in GC. Mechanistically, E2F5 promoted UBE2T transcription and UBE2T overexpression reversed the effects of E2F5 depletion on the proliferation and invasion of cells in GC. Taken together, this study originally confirmed the upregulation of E2F5 in GC, revealed that E2F5 can directly upregulate UBE2T transcription, and subsequently promote the malignant progression, which highlights that the E2F5/UBE2T axis can potentially be used in the diagnosis and treatment of GC.

Bayesian hierarchical lasso Cox model: A 9-gene prognostic signature for overall survival in gastric cancer in an Asian population

Objective

Gastric cancer (GC) is one of the most common tumour diseases worldwide and has poor survival, especially in the Asian population. Exploration based on biomarkers would be efficient for better diagnosis, prediction, and targeted therapy.

Methods

Expression profiles were downloaded from the Gene Expression Omnibus (GEO) database. Survival-related genes were identified by gene set enrichment analysis (GSEA) and univariate Cox. Then, we applied a Bayesian hierarchical lasso Cox model for prognostic signature screening. Protein-protein interaction and Spearman analysis were performed. Kaplan–Meier and receiver operating characteristic (ROC) curve analysis were applied to evaluate the prediction performance. Multivariate Cox regression was used to identify prognostic factors, and a prognostic nomogram was constructed for clinical application.

Results

With the Bayesian lasso Cox model, a 9-gene signature included TNFRSF11A, NMNAT1, EIF5A, NOTCH3, TOR2A, E2F8, PSMA5, TPMT, and KIF11 was established to predict overall survival in GC. Protein-protein interaction analysis indicated that E2F8 was likely related to KIF11. Kaplan-Meier analysis showed a significant difference between the high-risk and low-risk groups (P<0.001). Multivariate analysis demonstrated that the 9-gene signature was an independent predictor (HR = 2.609, 95% CI 2.017–3.370), and the C-index of the integrative model reached 0.75. Function enrichment analysis for different risk groups revealed the most significant enrichment pathway/term, including pyrimidine metabolism and respiratory electron transport chain.

Conclusion

Our findings suggested that a novel prognostic model based on a 9-gene signature was developed to predict GC patients in high-risk and improve prediction performance. We hope our model could provide a reference for risk classification and clinical decision-making.

Gastric cancer cell-derived extracellular vesicles elevate E2F7 expression and activate the MAPK/ERK signaling to promote peritoneal metastasis through the delivery of SNHG12

Cancer cell-derived extracellular vesicles (EVs) have extensive application in the formation of their environment, including metastasis. This study explored the ability of gastric cancer (GC) cell-derived EVs-mediated microRNA-129-5p/E2F transcription factor 7/mitogen-activated protein kinase/extracellular regulated protein kinase (miR-129-5p/E2F7/MAPK/ERK) axis to affect the peritoneal metastasis of GC by delivering lncRNA small nucleolar RNA host gene 12 (SNHG12). EV-derived lncRNA and SNHG12/miR-129-5p/E2F7 network were determined by bioinformatics analysis. The regulatory relationship among SNHG12, miR-129-5p, and E2F7 was verified using a combination of dual-luciferase reporter gene, RNA immunoprecipitation, and RNA pull-down assays. The SNHG12, miR-129-5p, and E2F7 expression was measured by RT-qPCR. After GC cell-derived EVs were isolated and co-cultured with human peritoneal mesothelial cells (HPMCs), the uptake of EVs by HPMCs was observed under laser scanning confocal microscopy. Cell viability and apoptosis were examined using cell counting kit-8 and flow cytometry, respectively. Western blot analysis was performed to measure the mesothelial–mesenchymal transition (MMT)-related protein expression. The pathological and morphological characteristics of metastatic tumors in nude mice were observed by hematoxylin–eosin staining. A high SNHG12 expression was correlated with the poor prognosis of patients with GC. GC-derived EVs led to increased HPMC apoptosis and MMT by transferring SNHG12, whereas the knockdown of SNHG12 annulled the aforementioned results. SNHG12 sponged miR-129-5p to boost E2F7 expression and activate the MAPK/ERK signaling, thus inducing HPMC apoptosis and MMT. In vivo experiments further verified that EVs derived from GC cells promoted peritoneal metastasis in nude mice. GC cell-derived EVs elevated the E2F7 expression and activated the MAPK/ERK signaling to promote peritoneal metastasis through the delivery of SNHG12.

Impact of Cancer Stem Cells on Therapy Resistance in Gastric Cancer

Gastric cancer (GC) is the fourth leading cause of cancer death worldwide, with an average 5-year survival rate of 32%, being of 6% for patients presenting distant metastasis. Despite the advances made in the treatment of GC, chemoresistance phenomena arise and promote recurrence, dissemination and dismal prognosis. In this context, gastric cancer stem cells (gCSCs), a small subset of cancer cells that exhibit unique characteristics, are decisive in therapy failure. gCSCs develop different protective mechanisms, such as the maintenance in a quiescent state as well as enhanced detoxification procedures and drug efflux activity, that make them insusceptible to current treatments. This, together with their self-renewal capacity and differentiation ability, represents major obstacles for the eradication of this disease. Different gCSC regulators have been described and used to isolate and characterize these cell populations. However, at the moment, no therapeutic strategy has achieved the effective targeting of gCSCs. This review will focus on the properties of cancer stem cells in the context of therapy resistance and will summarize current knowledge regarding the impact of the gCSC regulators that have been associated with GC chemoradioresistance.

E2F1/2/4 mRNA is associated with immune infiltration and are potential biomarkers for the prognosis of human gastric carcinoma

Background

E2Fs are genes that regulate DNA synthesis and the cell cycle by encoding a family of transcription factors. Increasing experimental evidence has revealed that E2Fs play key roles in tumor progression in various types of cancer.

Methods

We investigated the survival, expression and transcriptional data of E2F1/2/4 in gastric cancer (GC) patients using the immunohistochemistry assay, Kaplan-Meier Plotter, cBioPortal, String, and GEPIA databases. The plasma of GC patients was analyzed using the real-time reverse transcription polymerase chain reaction (RT-PCR) assay. The correlation between E2F1/2/4 expression and clinical features was analyzed using the quartile method. As well, the correlation between E2F1/2/4 and GC immune infiltration was also investigated using the TIMER database. Database of Immune Cell Expression (DICE) was also used to analyze correlations between SOX4 and immune responses.

Results

RT-PCR and tissue immunohistochemistry confirmed that E2F1/2/4 was highly expressed in serum and GC tissue samples of GC patients, the expression of which was not affected by patient age and gender. Also, the survival analysis revealed that low levels of E2F1/2/4 expression were significantly associated with a longer overall survival (OS) in GC patients. E2F1/2/4 was correlated with patient prognosis and immune cell infiltration, including B cells, CD8⁺ T cells, CD4⁺ T cells, macrophages, neutrophils, and DCs in GC. Our findings indicated that E2F1/2/4 could be used as a prognostic biomarker and indicator of immune infiltration in GC.

Conclusions

This study revealed that E2F1/2/4 could be a promising indicator for tumor-associated immune infiltration and prognosis in GC patients.

Identification of the Expression and Clinical Significance of E2F Family in Clear Cell Renal Cell Carcinoma

Background

Multiple studies have identified that E2F transcriptions act as important regulators for the tumorigenesis and progression of several human cancers. However, little is known about the function of E2Fs in clear cell renal cell carcinoma (ccRCC).

Methods

We firstly investigated the expression levels, genetic alteration, and biological function of E2Fs in patients with ccRCC and the connections between the immune cell infiltration and the overall survivals of ccRCC patients with the E2Fs expression levels based on UALCAN, The Cancer Genome Atlas database, Gene Expression Profiling Interactive Analysis, TIMER, STRING, GSCALite and cBioPortal databases.

Results

Results revealed that the expression levels of E2F1/2/3/4/6/7/8 were markedly upregulated in patients with ccRCC, while the expression of E2F5 displayed an opposite trend. We also experimentally validated the overexpression of E2F3/4/7 in human ccRCC tissues and ccRCC cell lines. Furthermore, the high E2F1/2/3/4/7/8 expression levels were clearly associated with worse pathological characteristics of ccRCC, including high pathological stage, poor molecular subtypes and high tumor grade. Meanwhile, high expression levels of E2F1/2/4/7/8 were evidently associated with worse overall survivals (OSs) and progression-free survivals (PFSs) of patients harboring ccRCC. Univariate and multivariate analyses illustrated that the expressions of E2F4/5/7 were independent factors associated with the OSs and PFSs of patients with ccRCC. Meanwhile, the mutations in E2Fs were also significantly related to poor OSs and PFSs of patients with ccRCC. Mechanically, the E2Fs genes synergistically promoted the progression of ccRCC by accelerating the cell cycle and inhibiting DNA damage response and apoptosis after performing the protein structure, functional enrichment, and PPI network analyses. In addition, E2Fs genes were also significantly associated with tumor immune cells infiltration and the drug sensitivity in ccRCC.

Conclusion

As a result, E2F4/7 were highly expressed in ccRCC and significantly associated with worse pathological characteristics of ccRCC, including high pathological stage, poor molecular subtypes and high tumor grade, tumor immune cell infiltration, and drug sensitivity, consequently translating into poor OSs and PFSs of patients with ccRCC. Our results indicated that E2F4/7 could be potential biomarkers and therapeutic targets of ccRCC patients.

ZNF750 exerted its Antitumor Action in Oral Squamous Cell Carcinoma by regulating E2F2

Cell cycle activator E2F transcription factor 2 (E2F2) play a key role in tumor development and metastasis. Previous RNA sequence analysis (GSE134835) revealed E2F2 was significantly reduced by Zinc-finger protein 750 (ZNF750) in oral squamous cell carcinoma (OSCC). This study was aimed to determine the involvement of E2F2 in antitumor action of ZNF750. The nude mouse xenograft model was established by subcutaneously injection of stable cell line CAL-27^oeZNF750 or CAL-27^shZNF750. Xenograft tumor volume and tumor weight was measured. The expression of E2F2, transcriptional repressors such as enhancer of zeste 2 (Ezh2), PHD finger protein 19 (PHF19), and the genes related to cell proliferation or metastasis was studied in vivo or in vitro. Luciferase assay was performed to investigate regulation effect of ZNF750 on E2F2 luciferase activity. The involvement of E2F2 in the antitumor action of ZNF750 was studied by cotransduced ZNF750 with E2F2 lentivirus. The tumor growth and metastasis was repressed by ZNF750 manifested by reduced tumor size, tumor weight and the genes related to cell proliferation and metastasis. However, all of these were reversed by knockdown of the ZNF750 gene. Furthermore, E2F2 luciferase activity was inhibited by ZNF750. E2F2 partly blocked the antitumor action of ZNF750 manifested by increased self-renewal, invasion, migration, elevated Ezh2 and MMP13 protein expression in ZNF750 + E2F2 groups. However, silenced E2F2 further enhanced the antitumor action of ZNF750. ZNF750 depressed E2F2 activity and played a critical role in regulating transcriptional repressors for inhibiting the OSCC growth and metastasis in OSCC.

Expression and Prognostic Role of E2F2 in Hepatocellular Carcinoma

Introduction

Hepatocellular carcinoma (HCC) is a common clinical malignancy. Recent studies reported that E2F transcription factor 2 (E2F2) plays a significant role in tumor progression. However, its expression and biological function in HCC are still unclear. Therefore, we explored the relationship between E2F2 expression and tumor progression in HCC.

Methods

In this study, we utilized some online tools to explore the E2F2 expression in pan-carcinoma and HCC. The association of E2F2 expression with the clinical characteristics and prognosis of HCC was further studied. In addition, we explored the co-expressed genes of E2F2 and mined the positively/negatively corrected significant genes and excavated the possible functions. Meanwhile, the hub gene set was constructed based on protein-protein interaction (PPI) network, and the relationship between E2F2 and immunity was discovered.

Results

We observed that the expression level of E2F2 was generally upregulated in HCC. However, E2F2 expression was not significantly different between HCC and normal tissues in regard to the disease stage 4. Furthermore, we also observed the poor prognosis in patients with high E2F2 expression. The co-expressed genes of E2F2 were identified and further detected. Thereafter, we identified the positively/negatively corrected significant genes and constructed the hub gene network of E2F2 based on PPI network. We also found that E2F2 expression was positively correlated with the infiltration levels of CD4+ T, CD8+ T cells, macrophages, neutrophils, and dendritic cells.

Conclusion

Our findings suggested that E2F2 could be a potential prognostic factor for HCC, which could provide a therapeutic target for the molecular treatment of HCC.

Integrated Analysis of Mutations, miRNA and mRNA Expression in Glioblastoma

Background

Glioblastoma multiforme (GBM) is a common, malignant brain tumor in adults, with a median survival of only 15–23 months. Organisms respond to disease stress through sophisticated mechanisms at the physiological, transcriptional and metabolic levels. However, the molecular regulatory networks responsible for occurrence, progression and recurrence of glioma have yet to be elucidated.

Methods

In this study, we sought to determine the cause of gliomas by developing an RNA-seq technique that analyzes mRNA and small RNA (sRNA) with the aim of discovering potential methods for precisely blocking key signaling pathways in occurrence, progression, and recurrence. The explication of mechanisms leading to GBM formation has become a feasible and promising new therapeutic method.

Results

GBM-associated genes were identified based on their expression during the disease stress response. Analysis of the inverse correlations between microRNAs (miRNAs) and target mRNAs revealed 43 mRNA–miRNA interactions during disease progression. BOC-SMO and BOC-RAS were found to promote the malignant progression of glioma. A total of 3088 differentially expressed genes were identified as involved in several biological processes, such as amino acid metabolism, protein transport associated with immune response, cell proliferation, and cell apoptosis. Fifteen miRNAs were also identified as being differentially expressed in GBM and control groups.

Conclusion

The results of this study provide an important foundation for understanding the pathogenesis of glioma and discovering new therapeutic targets.

Genetic variants of cell cycle pathway genes are associated with head and neck squamous cell carcinoma in the Chinese population

Genetic alterations in the cell cycle pathway are common in head and neck squamous cell carcinoma (HNSCC). We identified four novel HNSCC susceptibility loci (CDKN1C rs452338, CDK4 rs2072052, E2F2 rs3820028 and E2F2 rs2075993) through a two-stage matched case-control study. There was a combined effect among the four single nucleotide polymorphisms (SNPs), as the number of risk genotypes increased, the risk of HNSCC displayed an increasing trend (Ptrend < 0.001). And there were multiplicative interactions between rs452338 and rs2072052, rs2072052 and rs3820028, rs2072052 and rs2075993. Functional bioinformatics analysis and dual-luciferase reporter assay revealed that E2F2 rs2075993 T>C reduced the stability of E2F2 3'-UTR secondary structure and affected the binding of E2F2 to miR-940, which was up-regulated in HNSCC tumor tissues (P = 2.9e-8) and was correlated with poor overall survival of HNSCC (HR = 1.39, 95% CI = 1.02-1.90). In vitro assays, we discovered that the expression of miR-940 was regulated by METTL3, and miR-940 promoted the proliferation, migration and invasion, and inhibited the senescence and autophagy of tumor cells. In terms of mechanism, compared with rs2075993 allele T, we found that the protective variant rs2075993 allele C interfered with the translational inhibition of E2F2 by miR-940, resulting in increased expression of E2F2 protein, which further reduced the proliferation, migration, invasion, and increased the senescence of tumor cells.

Comprehensive Analysis of E2F Family Members in Human Gastric Cancer

Gastric cancer (GC) is the second most common cancer and the third most frequent cause of cancer-related deaths in China. E2Fs are a family of transcription factors reported to be involved in the tumor progression of various cancer types; however, the roles of individual E2Fs are still not known exactly in tumor progression of GC. In this study, we examined the expression of E2Fs to investigate their roles in tumor progression in GC patients using multiple databases, including ONCOMINE, GEPIA2, Kaplan-Meier plotter, cBioPortal, Metascape, LinkedOmics, GeneMANIA, STRING and UCSC Xena. We also performed real-time polymerase chain reaction (RT-PCR) to validate the expression levels of individual E2Fs in several GC cell lines. Our results demonstrated that the mRNA levels of E2F1/2/3/5/8 were significantly higher both in GC tissues and cell lines. The expression levels of E2F1 and E2F4 were correlated with poor overall survival (OS), decreased post-progression survival (PPS), and decreased progression-free survival (FP) in patients with GC. However, overexpression of E2F2, E2F5, E2F7 and E2F8 is significantly associated with disease-free survival and overall survival in patients with GC. In addition, higher E2F3 and E2F6 mRNA expression was found to increase GC patients' OS and PPS. 224 of 415 patients with STAD (54%) had gene mutations that were associated with longer disease-free survival (DFS) but not OS. Cell cycle pathway was closely associated with mRNA level of more than half of E2Fs (E2F1/2/3/7/8). There were close and complicated interactions among E2F family members. Finally, our results indicated the gene expressions of E2Fs had a positive relationship with its copy numbers. Taken together, E2F1/2/3/5/8 can serve as biomarkers for GC patients with high prognostic value for OS of GC patients or therapeutic targets for GC.

Knockdown of E2F4 suppresses the growth of ovarian cancer cells through the cell cycle pathway

Ovarian cancer remains one of the major causes of death from gynecologic cancer in developed countries. The E2F family has been shown to have a central role in the control of cell proliferation, differentiation, and cell cycle progression in various types of cancer. Despite advances in cancer research, the carcinogenic role of E2F transcription factor 4 (E2F4) in ovarian cancer remains unclear. In this study, we investigated the underlying molecular mechanism of E2F4 in human ovarian cancer cells (OCC). E2F4 expression was demonstrated by quantitative real time polymerase chain reaction (qRT-PCR) in OCC. The alterations of expression values were determined using 2^(-ΔΔCt) method. The effects of suppressing E2F4 on cell proliferation, migration, and differentiation were evaluated by cell proliferation assay, colony formation assay and wound healing assay in vitro. Overexpression of E2F4 was found at both mRNA and protein levels in OCC. Small interfering RNA was used to suppress E2F4 expression. Depletion of E2F4 inhibited cell proliferation and suppressed the cell migration and colony formation ability compared to controls. The expression of cell cycle machinery including cyclin A, cyclin D and cyclin dependent kinase 2 (CDK2) was increased after E2F4 knockdown. E2F4 modulates ovarian cancer cell proliferation and migration through cell cycle components including cyclin A, cyclin D, and CDK2. Our findings indicate that E2F4 may serve as a valuable candidate and therapeutic target for ovarian cancer treatment in regard to cell cycle control.

E2F1 transcriptionally regulates CCNA2 expression to promote triple negative breast cancer tumorigenicity

BACKGROUND

Triple-negative breast cancer (TNBC) is a highly malignant breast cancer subtype with a poor prognosis. The cell cycle regulator cyclin A2 (CCNA2) plays a role in tumor development. Herein, we explored the role of CCNA2 in TNBC.

METHODS

We analyzed CCNA2 expression in 15 pairs of TNBC and adjacent tissues and assessed the relationship between CCNA2 expression using the tissue microarray cohort. Furthermore, we used two TNBC cohort datasets to analyze the correlation between CCNA2 and E2F transcription factor 1 (E2F1) and a luciferase reporter to explore their association. Through rescue experiments, we analyzed the effects of E2F1 knockdown on CCNA2 expression and cellular behavior.

RESULTS

We found that CCNA2 expression in TNBC was significantly higher than that in adjacent tissues with similar observations in MDA-MB-231 and MDA-MB-468 cells. E2F1 was highly correlated with CCNA2 as observed through bioinformatics analysis (R= 0.80, P< 0.001) and through TNBC tissue verification analysis (R= 0.53, P< 0.001). We determined that E2F1 binds the +677 position within the CCNA2 promoter. Moreover, CCNA2 overexpression increased cell proliferation, invasion, and migration owing to E2F1 upregulation in TNBC.

CONCLUSION

Our data indicate that E2F1 promotes TNBC proliferation and invasion by upregulating CCNA2 expression. E2F1 and CCNA2 are potential candidates that may be targeted for effective TNBC treatment.

Prognostic Values of E2F1/2 Transcriptional Expressions in Chromophobe Renal Cell Carcinoma Patients: Evidence from Bioinformatics Analysis

Background

Numerous studies on the E2F transcription factors have led to increasing insights that E2Fs could be an important driver of the formation and progression of many human cancers. Little is known about the function of distinct E2Fs in chromophobe renal cell carcinoma (chRCC).

Methods

We utilized the UALCAN, GEPIA, Cancer Genome Atlas (TCGA) database, cBioPortal, Metascape, STRING, Cytoscape, GeneMANIA, TIMER, TISIDB, GSCALite, and MEXPRESS databases to investigate the transcription level, genetic alteration, methylation, and biological function of E2Fs in chRCC patients, and its association with the occurrence, progress, prognosis, and immune cell infiltration in patients with chRCC.

Results

We found that E2F1/2/4/7/8 were more expressed in chRCC tissues than in normal tissues, while the expression of E2F5/6 was lower in the former than in the latter, and the expression levels of E2F1/2/4/5/6//7/8 were also associated with the histological parameters of chRCC, including T-stage and N-stage. Higher expression of E2F1/2/7/8 was found to be significantly correlated with worse overall survival (OS) in chRCC patients. Cox regression and time-dependent ROC analysis further suggested that E2F1/2 could be the potential independent biomarkers for chRCC prognosis. Besides, a moderate mutation rate of E2Fs (34%) was noticed in chRCC, and the genetic mutations in E2Fs were associated with poor survival of chRCC patients. We noticed that the expression of E2Fs was statistically correlated with the immune cell infiltration in chRCC. Moreover, we also found that the expression of E2F1 was significantly correlated with tumor-infiltrating lymphocytes and immunomodulators, E2F7 expression was associated with MHC molecules, and the expression of E2F1/8 was correlated to their methylation levels.

Conclusion

Our results provide novel insights for selecting the prognostic biomarkers for chRCC and suggest that E2F1/2 could act as potential prognostic biomarkers for the survival of chRCC patients. However, more in-depth experiments are required to identify the underlying mechanisms and verify the clinical value of E2F1/2 in the prognosis of chRCC.

The RNA-Binding Protein NELFE Promotes Gastric Cancer Growth and Metastasis Through E2F2

Worldwide, the incidence rate of gastric cancer ranks fifth, and the mortality rate of gastric cancer ranks third among all malignant tumors. However, the pathogenesis of gastric cancer remains poorly understood. In this study, we demonstrated that the expression level of NELFE is higher in human gastric cancer tissues than in adjacent nontumor tissues. A high level of NELFE is associated with worse postoperative overall survival (OS) and relapse-free survival (RFS) rates in patients with gastric cancer. Moreover, the expression of NELFE is correlated with high tumor grade and lymph node metastasis in gastric cancer patients. Knockdown of NELFE dramatically inhibits the cell proliferation and metastasis of gastric cancer xenografts in vivo. Furthermore, we found that NELFE binding to the 3'UTR of E2F2 affects the mRNA stability of E2F2 to regulate the expression level of E2F2. In gastric cancer, E2F2 also acts as an oncogene to inhibit the proliferation and migration of gastric cancer cells by knocking down the expression level of E2F2. However, overexpressing E2F2 in cells with NELFE knockdown significantly reverses the inhibition of cell proliferation and migration induced by NELFE knockdown. Therefore, NELFE at least partially functions as an oncogene through E2F2. Moreover, CIBERSORTx analysis of the proportion of tumor-infiltrating immune cells (TICs) revealed that immune cells are correlated with NELFE and E2F2 expression, suggesting that NELFE and E2F2 might be responsible for the preservation of the immunodominant status for gastric cancer. In conclusion, NELFE acts as an oncogene in gastric cancer and can be used as a potential therapeutic target.

Analysis of Gastric Cancer Transcriptome Allows the Identification of Histotype Specific Molecular Signatures With Prognostic Potential

Gastric cancer is the fifth most common malignancy but the third leading cause of cancer-associated mortality worldwide. Therapy for gastric cancer remain largely suboptimal making the identification of novel therapeutic targets an urgent medical need. In the present study we have carried out a high-throughput sequencing of transcriptome expression in patients with gastric cancers. Twenty-four patients, among a series of 53, who underwent an attempt of curative surgery for gastric cancers in a single center, were enrolled. Patients were sub-grouped according to their histopathology into diffuse and intestinal types, and the transcriptome of the two subgroups assessed by RNAseq analysis and compared to the normal gastric mucosa. The results of this investigation demonstrated that the two histopathology phenotypes express two different patterns of gene expression. A total of 2,064 transcripts were differentially expressed between neoplastic and non-neoplastic tissues: 772 were specific for the intestinal type and 407 for the diffuse type. Only 885 transcripts were simultaneously differentially expressed by both tumors. The per pathway analysis demonstrated an enrichment of extracellular matrix and immune dysfunction in the intestinal type including CXCR2, CXCR1, FPR2, CARD14, EFNA2, AQ9, TRIP13, KLK11 and GHRL. At the univariate analysis reduced levels AQP9 was found to be a negative predictor of 4 years survival. In the diffuse type low levels CXCR2 and high levels of CARD14 mRNA were negative predictors of 4 years survival. In summary, we have identified a group of genes differentially regulated in the intestinal and diffuse histotypes of gastric cancers with AQP9, CARD14 and CXCR2 impacting on patients' prognosis, although CXCR2 is the only factor independently impacting overall survival.

E2F1 Maintains Gastric Cancer Stemness Properties by Regulating Stemness-Associated Genes

Purpose

To determine the regulatory role of E2F1 in maintaining gastric cancer stemness properties and the clinical significance of E2F1 in gastric cancer.

Materials and Methods

We conducted a tumor spheroid formation assay to enrich gastric cancer stem-like cells. The protein and mRNA expression levels of genes were measured using Western Blot and qRT-PCR. Lentivirus-mediated overexpression and downregulation of E2F1 were performed to evaluate the effect of E2F1 on the stemness properties of gastric cancer cells. The effect of E2F1 on gastric cancer cell sensitivity of 5-Fu was evaluated using cell viability assay and TdT-mediated dUTP Nick-End Labeling staining. We also analyzed the association between E2F1 expression and clinical characteristics in gastric cancer patients. The KM plotter database was used to analyze the relationship between E2F1 and overall survival in GC patients.

Results

We found that E2F1 expression was significantly higher in gastric cancer tissues than in the paired adjacent normal tissues (p < 0.05) and was positively correlated with tumor size (p < 0.05), T stage (p < 0.05), and differentiation degree (p < 0.05). KM plotter database demonstrated a close association between higher E2F1 expression level and worse overall survival of gastric cancer patients (p < 0.05). In vitro assay illustrated that E2F1 could regulate the expression of stemness-associated genes, such as BMI1, OCT4, Nanog, and CD44, and maintain the tumor spheroid formation ability of gastric cancer cells. E2F1 enhanced 5-Fu resistance in gastric cancer cells, and the E2F1 expression level was correlated with the prognosis of gastric cancer patients receiving 5-Fu therapy. The expression levels of stemness-associated genes were also significantly higher in gastric cancer tissues than the paired adjacent normal tissues (p < 0.05). A positive correlation was observed between E2F1 and BMI1 (r = 0.422, p < 0.05), CD44 (r = 0.634, p < 0.05), OCT4 (r = 0.456, p < 0.05), and Nanog (r = 0.337, p < 0.05) in gastric cancer tissues. The co-overexpression of E2F1 and stemness-associated genes was associated with worse overall survival.

Conclusion

E2F1 plays a significant role in gastric cancer progression by maintaining gastric cancer stemness properties through the regulation of stemness-associated genes. The close association between E2F1 and poor prognosis of patients suggests that E2F1 could serve as a prognostic biomarker and a therapeutic target in gastric cancer patients.

LINC00200 contributes to the chemoresistance to oxaliplatin of gastric cancer cells via regulating E2F1/RAD51 axis

The goal of this research was to decipher the biological functions and mechanism of long intergenic non-protein coding RNA 200 (LINC00200) in gastric cancer (GC). In this study, our data confirmed that LINC00200 expression was up-regulated in GC tissues and its high expression was correlated with the poor differentiation of GC tissues and lymph node metastasis of the patients. In vitro experiments indicated that, the overexpression of LINC00200 facilitated the proliferation of GC cells, constrained their apoptosis, and increased the IC₅₀ of oxaliplatin (Oxa), whereas knockdown of LINC00200 exhibited the opposite effects. Additionally, we demonstrated that LINC00200 could bind to E2F transcription factor 1 (E2F1), and the up-regulation of LINC00200 expression enhanced the binding between E2F1 and RAD51 promoter, hence promoting RAD51 transcription, while knockdown of LINC00200 inhibited the transcription of RAD51. In conclusion, LINC00200 may recruit E2F1 to the RAD51 recombinase (RAD51) promoter region, thereby up-regulating the expression of RAD51 and enhancing the chemoresistance of GC cells to Oxa. Our data suggested that LINC00200 could probably be a promising target for treating GC.

OSchol: an online consensus survival web server for cholangiocarcinoma prognosis analysis

BACKGROUND

As the most common biliary ducts, cholangiocarcinoma (CHOL) is an aggressive malignancy with complex pathological context, high mortality and relapse rate. The current therapy of CHOL is mainly performed with surgery followed by chemoradiotherapy. Due to the high metastasis and relapse rate of CHOL, the prognosis of CHOL is still poor, and the molecular prognostic system is to be constructed.

METHODS

In this study, we have established an online prognostic analysis web server named OSchol to evaluate the correlation between candidate genes and survival for CHOL.

RESULTS

The prognostic values of previous published biomarkers in OSchol, including ITIH4, PTEN and DACH1, have been validated by OSchol. In addition, we have identified novel potential prognostic biomarker for CHOL using OSchol, that E2F1 has significant prognostic ability in OSchol (both TCGA and GSE107943 cohorts).

CONCLUSION

Our study provides a platform for researchers and clinicians to screen, develop and validate their genes of interest to be potential prognostic biomarkers for CHOL and may also help guide the targeted therapies for CHOL.

DNA polymerase theta repression enhances the docetaxel responsiveness in metastatic castration-resistant prostate cancer

OBJECTIVE

Docetaxel remains a main treatment for metastatic castration-resistant prostate cancer (mCRPC); however, the development of docetaxel resistance has been found in some mCRPC patients. The aim of this work is to identify an effective biomarker for predicting therapeutic effectiveness of docetaxel in mCRPC patients.

METHODS

We examined DNA polymerase theta (POLQ) expression in The Cancer Genome Atlas (TCGA) database and Tissue microarray. Kaplan-Meier analyses were performed to estimate the prognostic significance of POLQ. A series of functional analyses were conducted in cell lines and xenograft models. Regulated pathways were predicted by Geneset Enrichment Analysis (GSEA) software and further investigated by luciferase reporter and RT-PCR assays.

RESULTS

We found that POLQ mRNA levels in CRPC tissues was significantly higher than that of other DNA polymerases in non-CRPC prostate tissues. POLQ upregulation was extensively detected in mCRPC and strongly predicted a poor prognosis. POLQ knockdown enhanced docetaxel sensitivity in a cell-based cytotoxicity assay and promoted the therapeutic effect on the tumor growth of metastatic PC-3M cells in xenograft models. The computational simulation by GSEA software significantly predicted the association between POLQ upregulation and the activation of E2F/G2M checkpoint-related pathways. Moreover, luciferase reporter and RT-PCR assays demonstrated that POLQ knockdown downregulated the transcriptional regulatory activity of E2F and repressed E2F/G2M checkpoint-regulated CDK1 in mCRPC cells.

CONCLUSION

Our results suggest that POLQ serves as a predictive factor for poor docetaxel response and provide a novel strategy to enhance the anticancer effects of docetaxel therapy by targeting POLQ in mCRPC patients.

Bioinformatics Identification of the Expression and Clinical Significance of E2F Family in Endometrial Cancer

Background

Besides being one of the most prevalent cancers among women, incidence and mortality rates of endometrial cancer (EC) are still increasing. The E2F family of transcriptional factors is involved in cell differentiation, apoptosis, and inhibition of DNA damage response, thus affecting growth and invasion of tumor cells.

Methods

We used multiple bioinformatics tools to explore the role of E2F family in endometrial cancer.

Results

The expression of E2F1/2/3/7/8 was significantly upregulated in endometrial cancer tissues, converse to E2F4, which was downregulated. Methylation downregulates all E2Fs except for E2F2. Accordingly, E2F1/2/3/5/7/8 are potential diagnostic biomarkers for EC. In particular, EC patients displaying upregulated E2F1, and E2F3 expression had a worse overall survival and relapse-free survival. E2F8, E2F7, and E2F1 were the top three, most-frequently altered genes in endometrial cancer. E2F family activates apoptosis pathways, regulates cell cycle, and impairs DNA damage response pathways. Drug-sensitivity analysis demonstrated that the level of E2F2/3/8 negatively correlated with drug resistance. Meanwhile, immune infiltrations analysis revealed that E2F family is associated with recruitment of several immune cells. Enrichment analysis on its part revealed that the E2F family is mainly associated with cell cycle, sequence-specific DNA binding, nuclear transcription factor complex, PI3K-Akt signaling, and p53 signaling pathway. We also identified multiple E2Fs-associated miRNA and kinase targets in endometrial cancer.

Conclusion

Our study revealed the unique expression signature and clinical significance of E2F family in EC, demonstrating the potential clinical utility of these transcription factors (TF) in endometrial cancer.

Novel Potential Therapeutic Target for E2F1 and Prognostic Factors of E2F1/2/3/5/7/8 in Human Gastric Cancer

E2F transcription factors (E2Fs) were found to be related with cell activities and disease progression among a variety of different tumors, including regulating cell division and cell proliferation. In the analysis, it aimed to focus on transcriptional and survival information of E2Fs in gastric cancer (GC) from Gene Expression Profiling Interactive Analysis (GEPIA), Kaplan-Meier plotter, cBioPortal, Database for Annotation, Visualization and Integrated Discovery (DAVID), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway, and Oncomine databases. It was found that the expression of E2F1/2/3/5/7/8 in GC tissues was obviously higher than the normal. Of interest, none of the E2Fs was related with pathological stages. Nevertheless, high expression of E2F2/3/5/7/8 was related with better survival data, except E2F6 regarding shorter first-progression (FP) survival. High expression levels of E2F2/5/7/8 have significant correlations with overall survival (OS) in patients with intestinal and diffuse GC, and this prognostic value is not affected by gender. Oppositely, the lower level of E2F1/4 illustrated superior survival data. Moreover, increased expression of E2F1 in GC tissues might play an important role in the development of GC. Collectively, E2F1 could be a potential therapeutic target for patients with GC. E2F1/2/3/5/7/8 might be original prognostic predictors of GC.

Triptolide Inhibits the Proliferation of HaCaT Cells Induced by IL22 via Upregulating miR-181b-5p

BACKGROUND

Evidence has been shown that triptolide was effective in the treatment of psoriasis; however, the mechanisms remain poorly understood. Thus, this study aimed to investigate the role of triptolide on the proliferation and differentiation of HaCaT cells which are treated with IL22 to mimic abnormal proliferation/differentiation in keratinocyte of psoriasis.

MATERIALS AND METHODS

HaCaT cells were transfected with miR-181b-5p antagomir for 24 h, and then exposed to 10 μM Triptolide for 24 h, following by 100 ng/mL of IL22 for 24 h. In addition, the proliferation and cell cycle distribution in HaCaT cells were assessed by immunofluorescence or flow cytometry assays, respectively.

RESULTS

Triptolide obviously upregulated the level of miR-181b-5p in HaCaT cells. In addition, triptolide significantly inhibited IL22-induced proliferation of HaCaT cells via inducing cell cycle arrest. Moreover, IL22 markedly inhibited the differentiation of HaCaT cells, and this phenomenon was reversed by triptolide treatment. In contrast, the effects of triptolide on the proliferation and differentiation in IL22-stimulated HaCaT cells were notably reversed by miR-181b-5p antagomir. Moreover, dual-luciferase assay showed that E2F5 was the direct target of miR-181b-5p in HaCaT cells. Meanwhile, upregulation of miR-181b-5p obviously decreased the level of E2F5 in HaCaT cells.

CONCLUSION

In this study, we found that triptolide could inhibit the proliferation and promote the differentiation in IL22-stimulated keratinocytes via upregulating miR-181b-5p. These data indicated that triptolide may be a potential agent for the treatment of psoriasis.

LncRNA HAND2-AS1 represses cervical cancer progression by interaction with transcription factor E2F4 at the promoter of C16orf74

Cervical cancer is one of the major malignancies, the pathophysiology and progression of which remain to be scarcely understood. Long non-coding RNAs (lncRNAs) have been previously implicated in the progression of cervical cancer. Here, the purpose of this study was to identify whether lncRNA heart- and neural crest derivative-expressed 2-antisense RNA 1 (HAND2-AS1) affect the development of cervical cancer through regulation of chromosome 16 open reading frame 74 (C16orf74) by mediating a transcription factor E2F4. RT-qPCR was performed to determine the expression of HAND2-AS1 in cervical cancer cells. Then, cervical cancer cells were treated with HAND2-AS1 or si-E2F4 RNA, or C16orf74, after which the proliferation, colony formation, migration and invasion were detected. Moreover, the binding between HAND2-AS1 and E2F4 or between E2F4 and C16orf74 was explored. Finally, the tumorigenesis of cervical cancer cells was measured in nude mice with altered HAND2-AS1/E2F4/C16orf74 expression. HAND2-AS1 exhibited poor expression in cervical cancer, and HAND2-AS1 overexpression suppressed the proliferation, colony formation, migration and invasion of cervical cancer cells. In addition, HAND2-AS1 was found to recruit transcription factor E2F4 to C16orf74 promoter region and down-regulate C16orf74 expression. Lastly, HAND2-AS1/E2F4/C16orf74 modulated the tumorigenesis of cervical cancer in nude mice. In conclusion, this study provided evidence on the inhibitory effect of HAND2-AS1 on the development of cervical cancer through the suppression of C16orf74 expression by recruiting transcription factor E2F4. This study highlights the potential of lncRNA HAND2-AS1 as a target in the treatment of cervical cancer.

Analysis of Gene Expression of miRNA-106b-5p and TRAIL in the Apoptosis Pathway in Gastric Cancer

Helicobacter pylori (H. pylori) is one of the main causes of gastric gancer. TNF-related apoptosis-inducing ligand (TRAIL) is a protein able to promote apoptosis in cancer cells, however not in gastric cancer, which presents resistance to apoptosis via TRAIL. It is believed that MicroRNA-106b-5p might be involved in this resistance, although its role in Gastric Cancer is unclear. We aimed to determine the expression of microRNA-106b-5p and TRAIL in patients with gastric diseases, infected by H. pylori, and understand the relationship between these genes and their role in apoptosis and the gastric cancer pathways. H. pylori was detected by PCR, gene expression analysis was performed by real-time-qPCR, and bioinformatics analysis was performed using the Kyoto Encyclopedia of Genes and Genomes (KEGG) and Cytoscape software. A total of 244 patients were divided into groups (Control, Gastritis, and Cancer); H. pylori was detected in 42.2% of the samples. The cancer group had a poor expression of TRAIL (p < 0.0001) and overexpression of microRNA-106b-5p (p = 0.0005), however, our results confirmed that these genes are not directly related to each other although both are apoptosis-related regulators. Our results also indicated that H. pylori decreases microRNA-106b-5p expression and that this is a carcinogenic bacterium responsible for gastric diseases.

Integrated analysis of the E2F transcription factors across cancer types

E2F transcription factors are associated with the development of cancer. However, the E2F family genes have not yet been studied in a comprehensive manner. Using The Cancer Genome Atlas, the present study analyzed the functions of the E2F family genes across different types of tumor. It was revealed that compared with normal tissues, the E2F family genes are highly expressed in several types of tumor tissue. Furthermore, E2F transcription factors were significantly enriched in tumor samples across different types of tumor. The high expression levels of E2F family genes were associated with an unfavorable prognosis in liver hepatocellular carcinoma (LIHC) and lung adenocarcinoma (LUAD). Furthermore, patients with pathological T1 stage and iCluster2 molecular subtype of LIHC expressed particularly low levels of E2F family genes. The present study demonstrated that hypo-DNA methylation, DNA amplification and TP53 mutation contributed to the high expression levels of E2F family genes in cancer cells. Finally, the present study revealed that, compared with other types of tumor, the E2F family genes were specifically downregulated in patients with LIHC. The expression levels and prognostic effects of the E2F family genes were validated using the Gene Expression Omnibus database. The results of the present study revealed the biological functions of E2F family genes in the development of cancer and provided potential biomarkers for further therapeutic studies, particularly for patients with LIHC and LUAD.

Upregulation of miRNA-154-5p prevents the tumorigenesis of osteosarcoma

BACKGROUND

Osteosarcoma (OS) is a primary malignant bone sarcoma in human worldwide. It has been shown that the level of microRNA-154-5p (miR-154-5p) was downregulated in human OS tissues. However, the mechanisms by which miR-154-5p regulates the proliferation, apoptosis and invasion in OS remain unclear. Thus, the present study aimed to investigate the role of miR-154-5p during the tumorigenesis of OS.

METHODS

The level of miR-154-5p in human OS tissues was detected by RT-qPCR. In addition, the effects of miR-154-5p on apoptosis and invasion of OS cells were assessed by flow cytometry and transwell assays, respectively. Meanwhile, the dual luciferase reporter system assay was performed to explore the interaction of miR-154-5p and E2F5.

RESULTS

The level of miR-154-5p was downregulated in OS tissues. Overexpression of miR-154-5p significantly inhibited the proliferation, migration and invasion of MG63 cells. In addition, upregulation of miR-154-5p obviously induced apoptosis in MG63 cells via upregulation of Bax and cleaved caspase 3, and downregulation of Bcl-2. Moreover, luciferase reporter assay identified that E2F5 was the binding target of miR-154-5p. Meanwhile, overexpression of miR-154-5p induced cell cycle arrest in MG63 cells via inhibiting the expressions of E2F5, Cyclin E1 and CDK2. Furthermore, in vivo assays indicated that overexpression of miR-154-5p notably inhibited the tumor growth in an OS xenograft model.

CONCLUSION

These results indicated that miR-154-5p may function as a potential tumor suppressor in OS. Therefore, miR-154-5p might be a novel therapeutic option for the treatment of OS.

The Long Non-Coding RNA SBF2-AS1 Exerts Oncogenic Functions In Gastric Cancer By Targeting The miR-302b-3p/E2F Transcription Factor 3 Axis

Background and aims

Studies show that the long non-coding RNA, SBF2-AS1, plays a critical role in cancer progression, but the role of SBF2-AS1 in gastric cancer has not been reported. Therefore, this study aimed to elucidate the mechanism of SBF2-AS1 in gastric cancer (GC).

Methods

A meta-analysis, based on the gene expression omnibus database and TCGA dataset was performed to explore the prognostic value of SBF2-AS1 in GC. RT-PCR was also conducted to investigate the clinicopathologic value of SBF2-AS1 in GC. The effect of SBF2-AS1 in GC cell lines was conducted by gain or loss-of-function assays, and the SBF2-AS1 target gene was confirmed using a luciferase reporter assay and bioinformatics.

Results

SBF2-AS1 was overexpressed in GC tissues and cell lines, and SBF2-AS1 overexpression indicated poor overall survival and could serve as an independent prognostic factor. Moreover, knockdown of SBF2-AS1 inhibited cell growth, invasion, and metastasis, promoted apoptosis, and caused cell cycle arrest. Luciferase reporter and gain- or loss-of-function assays indicated that SBF2-AS1 acted as a competing endogenous (ceRNA) for microRNA (miR)-302b-3p, which blocked the inhibitory effect of miR-302b-3p on the E2F transcription factor 3 (E2F3).

Conclusion

SBF2-AS1 could be a potential diagnostic and prognostic biomarker in GC, and SBF2-AS1 accelerates tumor progression via the miR-302b-3p/E2F3 axis.

Transcription factor E2F1 positively regulates interferon regulatory factor 5 expression in non-small cell lung cancer

Purpose

Lung cancer is the most common malignant tumor in the world, and its incidence and mortality are very high. This study focuses on the mechanism of non-small cell lung cancer to find new therapeutic targets.

Methods

We used RT-PCR and Western blot to verify the linear relationship between E2F1 and IRF5 in normal lung tissue and lung cancer tissues. Secondly, we used overexpression and knock down E2F1 in cell lines to detect the expression of IRF5. The prime enzyme reporter plasmid verified that E2F1 binds to the core promoter region of IRF5; finally, CHIP experiments demonstrated that E2F1 binds directly to IRF5.

Results

We verified that E2F1 and IRF5 are decreased in patient tissues, and there is a strong linear relationship between E2F1 and IRF5. Secondly, we used overexpression of E2F1 or E2F1 siRNA transfected into HCC827 cells and found that E2F1 positively regulates the activity of the IRF5 promoter and the mRNA level of IRF5. Finally, the results of a chromatin immunoprecipitation assay demonstrated that E2F1 bound to the promoter region of IRF5 in vitro. These results suggested that the E2F1 transcription factor is the primary determinant for activating the basal transcription of the IRF5.

Conclusion

The transcription factor E2F1 positively regulates IRF5 in non-small cell lung cancer.

The E2F3/miR-125a/DKK3 regulatory axis promotes the development and progression of gastric cancer

Background

Gastric cancer (GC) is one of the most common malignant tumours with high mortality and metastasis rates. E2F3, miR-125a and DKK3 have been reported to be involved in various cancer types, but their detailed roles in GC have not been fully understood.

Methods

A QRT-PCR assay was used to examine the expression of E2F3, miR-125a and DKK3 in metastatic and nonmetastatic GC tissues. DKK3 plasmids, DKK3 shRNA, miR-125a mimic and miR-125a inhibitor were transfected into BGC823 cells to evaluate the biological functions of DKK3 and miR-125a. A scratch wound healing assay and Transwell assay were utilized to determine the migratory and invasive ability of BGC823 cells transfected with the DKK3 plasmids, DKK3 shRNA, miR-125a mimic and miR-125a inhibitor. Moreover, qRT-PCR and WB analysis were used to analyse the mRNA and protein expression levels of metastasis-related genes after proper transfection. The target relationship between miR-125a and the DKK3 mRNA 3′UTR was determined by a dual luciferase reporter assay, while the interaction between E2F3 and miR-125a was analysed by a ChIP assay.

Results

The clinical data showed that the DKK3 expression level in metastatic GC samples was significantly less than that in nonmetastatic GC samples, whereas the E2F3 and miR-125a expression levels in metastatic GC samples were notably greater than those in nonmetastatic GC samples. Moreover, knockdown of DKK3 and overexpression of miR-125a markedly promoted the migratory and invasive abilities of GC cells. Additionally, the protein and mRNA expression levels of metastasis-related genes, including N-cadherin, Vimentin, MMP2 and MMP9, were markedly decreased in the DKK3 and miR-125a inhibitor groups compared to their control groups and markedly increased in the DKK3 shRNA and miR-125a groups compared with the control group. Finally, a dual luciferase reporter assay and ChIP assay showed that E2F3 binds to the miR-125a promoter and that the DKK3 mRNA 3′UTR is a direct target of miR-125a. Furthermore, analysis of Kaplan–Meier curves also confirmed the regulatory role of E2F3 on miR-125a. Additionally, BGC823 cells transfected with E2F3 plasmids and shRNA downregulated and upregulated the expression of DKK3, respectively.

Conclusion

Our results suggested that E2F3 might play a tumour-promoting role in the metastasis and progression of GC by regulating the miR-125a/DKK3 axis.

Comprehensive analysis of peroxiredoxins expression profiles and prognostic values in breast cancer

BACKGROUND

The peroxiredoxins (PRDXs) gene family has been demonstrated to participate in carcinogenesis and development of numerous cancers and the prognostic values in several cancers have been evaluated already. Purpose of our research is to explore the expression profiles and prognostic values of PRDXs in breast cancer (BrCa).

METHODS

The transcriptional levels of PDRX family members in primary BrCa tissues and their association with intrinsic subclasses were analyzed using UALCAN database. Then, the genetic alterations of PDRXs were examined by cBioPortal database. Moreover, the prognostic values of PRDXs in BrCa patients were investigated via the Kaplan-Meier plotter.

RESULTS

The transcriptional levels of most PRDXs family members in BrCa tissues were significantly elevated compared with normal breast tissues. Meanwhile, dysregulated PRDXs expression was associated with intrinsic subclasses of BrCa. Besides, copy number alterations (CNA) of PRDXs positively regulated their mRNA expressions. Furthermore, high mRNA expression of PRDX4/6 was significantly associated with poor overall survival (OS) in BrCa patients, while high mRNA expression of PRDX3 was notably related to favorable OS. Simultaneously, high mRNA expression of PRDX1/2/4/5/6 was significantly associated with shorter relapse-free survival (RFS) in BrCa patients, while high mRNA expression of PRDX3 was notably related to favorable RFS. In addition, the prognostic value of PRDXs in the different clinicopathological features based on intrinsic subclasses and chemotherapeutic treatment of BrCa patients was further assessed in the KM plotter database.

CONCLUSION

Our findings systematically elucidate the expression profiles and distinct prognostic values of PRDXs in BrCa, which might provide novel therapeutic targets and potential prognostic biomarkers for BrCa patients.

Identification of long noncoding RNA RP11-169F17.1 and RP11-669N7.2 as novel prognostic biomarkers of stomach adenocarcinoma based on integrated bioinformatics analysis

Aim: We aim to identify differentially expressed long noncoding RNAs (lncRNAs) and explored their functional roles in stomach adenocarcinoma. Materials & methods: Based on public omics data, we identified disregulated lncRNAs and investigated their prognostic values and potential functions based on ceRNA hypothesis. Results: Among the 52 differentially expressed lncRNAs, upregulated RP11-169F17.1 and RP11-669N7.2 were significantly associated with both poor overall survival and disease-free survival. RP11-169F17.1 and RP11-669N7.2 strongly correlated with microRNAs in cancer, cell proliferation and differentiation. RP11-169F17.1 and RP11-669N7.2 closely related to Helicobacter pylori infection-induced gastritis, duodenal ulcer, gastric cancer and mucosa-associated lymphoid tissue lymphoma. Conclusion: RP11-169F17.1 and RP11-669N7.2 act as novel prognostic biomarkers of stomach adenocarcinoma and may also play an important role in H. pylori infection-induced gastric diseases.

Identification of five hub genes as monitoring biomarkers for breast cancer metastasis in silico

BACKGROUND

Breast cancer is one of the most common endocrine cancers among females worldwide. Distant metastasis of breast cancer is causing an increasing number of breast cancer-related deaths. However, the potential mechanisms of metastasis and candidate biomarkers remain to be further explored.

RESULTS

The gene expression profiles of GSE102484 were downloaded from the Gene Expression Omnibus (GEO) database. Weighted gene co-expression network analysis (WGCNA) was used to screen for the most potent gene modules associated with the metastatic risk of breast cancer, and a total of 12 modules were identified based on the analysis. In the most significant module (R2 = 0.68), 21 network hub genes (MM > 0.90) were retained for further analyses. Next, protein-protein interaction (PPI) networks were used to further explore the biomarkers with the most interactions in gene modules. According to the PPI networks, five hub genes (TPX2, KIF2C, CDCA8, BUB1B, and CCNA2) were identified as key genes associated with breast cancer progression. Furthermore, the prognostic value and differential expression of these genes were validated based on data from The Cancer Genome Atlas (TCGA) and Kaplan-Meier (KM) Plotter. Receiver operating characteristic (ROC) curve analysis revealed that the mRNA expression levels of these five hub genes showed excellent diagnostic value for breast cancer and adjacent tissues. Moreover, these five hub genes were significantly associated with worse distant metastasis-free survival (DMFS) in the patient cohort based on KM Plotter.

CONCLUSION

Five hub genes (TPX2, KIF2C, CDCA8, BUB1B, and CCNA2) associated with the risk of distant metastasis were extracted for further research, which might be used as biomarkers to predict distant metastasis of breast cancer.