E2F1 Expression Research Articles

Retracted] MicroRNA‑34a expression affects breast cancer invasion in vitro and patient survival via downregulation of E2F1 and E2F3 expression.

Following the publication of the above paper, it was drawn to the Editor's attention by a concerned reader that there appeared to be overlapping sections of data in the three Transwell invasion assay images shown in Fig. 4A, and in the 3D sphere formation assay data shown in Fig. 5, on p. 2068; moreover, certain of the data featured in one of the data panels in Fig. 4A also appeared in a subsequent publication by the same research group in the journal Scientific Reports. The authors requested the publication of a corrigendum to acount for the errors made in assembling the data in Figs. 4 and 5; however, after careful consideration of the matter, the Editor of Oncology Reports has decided that this paper should be retracted from the Journal on account of the number of issues that were identified, and a general lack of confidence in the data. The authors were asked for an explanation to account for these concerns, but the Editorial Office did not receive a satisfactory reply. The Editor apologizes to the readership for any inconvenience caused. [Oncology Reports 43: 2062‑2072, 2020; DOI: 10.3892/or.2020.7549].

Pan-cancer Analysis Combined with Experiments Deciphers PHB Regulation for Breast Cancer Cell Survival and Predicts Biomarker Function.

Breast carcinoma has become the leading fatal disease among women. The location of prohibitin in the chromosome is close to the breast cancer susceptibility gene 1 (BRCA1). Accumulated research reported that prohibitin could interact with a variety of transcription factors and cell cycle-regulating proteins. This present study aims to comprehensively explore and reveal the biological functions of prohibitin on breast cancer via The Cancer Genome Atlas (TCGA) and validation experiment in vitro. Exploring the expression level of prohibitin across 27 tumors based on the TGGA database by bioinformatic methods and its relationship with tumor immune infiltration. Furthermore, we thus analyzed the biological roles of prohibitin on human breast cancer cell line MCF- 7 with pEGFP-prohibitin overexpression plasmid by western blotting and transwell-assay. Firstly, we found prohibitin is overexpressed in most tumors based on The Cancer Genome Atlas database, and the negative relationships between prohibitin and tumors infiltrating lymphocytes including B lymphocyte, CD4 T lymphocyte, CD8 T lymphocyte, Neutrophil, Macrophage and Dendritic, and its significant correlation with the prognosis of human cancer. In vitro, expression not only inhibited cell viability and invasive abilities but also increased the apoptosis percentage of cells with a decreased percentage of the S phase and an increased G2 phase. The reduction of Bcl-2 was observed when prohibitin was upregulated, although the expression of E2F-1 did not change. Although prohibitin is over-expressed in various cancer types, it functions as an important tumor suppressor that may suppress breast cancer cell proliferation and the invasive ability of MCF-7 by influencing its DNA synthesis and promoting cell apoptosis. All these may be likely associated with P53, erbB-2, and Bcl-2.

DTL promotes the growth and migration of melanoma cells through the ERK/E2F1/BUB1 axis

Melanoma is the most dangerous form of skin cancer. Hence, a better understanding of molecular mechanisms in melanoma pathogenesis is urgently needed, which provides a new insight into the therapy of melanoma. DTL gene is screened out in melanoma pathogenesis by integrated bioinformatics analysis, and its expression is validated in the tissue and cell samples of melanoma. Forced DTL expression facilitates the proliferation, invasion, migration and EMT of melanoma cells, while DTL knockdown suppresses the biological behavior of melanoma cells. In addition, DTL promotes the malignancy of melanoma in vivo. Mechanistically, BUB1 is the crucial downstream target of DTL. Reduced DTL expression suppresses BUB1 expression, while enhanced DTL expression induces BUB1 upregulation. Rescue experiments showed that growing and migrating of melanoma cells induced by DTL are partially impaired by BUB1 inhibition. In addition, the expression of phosphorylated ERK (p-ERK) and the downstream transcription factor E2F1 are reduced when DTL expression is blocked. Meanwhile, BUB1 levels are decreased when the expression of p-ERK or E2F1 is repressed. Notably, the growth and migration of melanoma cells by inhibition of ERK and knockdown of E2F1 was rescued by overexpressing BUB1. DTL gene may be a prognosis marker and represent a unique potential target for melanoma patients. DTL supports the biologically malignant activity of melanoma cells via the ERK/E2F1/BUB1 axis.

MiR-195-5p inhibits cisplatin resistance in lung adenocarcinoma by regulating DNA damage via targeting E2F7.

Lung adenocarcinoma (LUAD) emerges as one of the most lethal malignant tumors worldwide. Platinum-based combination chemotherapy remains one of the main methods for patients with advanced LUAD. Due to the resistance, the effect of this chemotherapy was not satisfactory. Therefore, studying the mechanism of cisplatin (DDP) resistance is essential for promoting the effect of this therapeutic strategy. Therefore, this work sought to probe the impact of E2F Transcription Factor 7 (E2F7) on LUAD resistance and the molecular regulatory mechanism. The mRNA expression level of the target gene E2F7 in LUAD was predicted by bioinformatics analysis, and regulatory miRNA upstream of the target gene was identified. The mRNA and protein expression of E2F7 in LUAD cells was detected through quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) and Western blot, respectively. The expression of miR-195-5p in LUAD cells was measured via qRT-PCR. E2F7 high and low expression groups underwent enrichment analysis by utilizing Gene Set Enrichment Analysis software. The targeting relationship of miR-195-5p and E2F7 was validated by conducting a dual-luciferase reporter assay. The cell viability was tested through cell counting kit-8. The cell cycle was examined by flow cytometry. DNA damage level was determined via Comet assay and Western blot assay. The findings indicated that the mRNA and protein levels of E2F7 were high in LUAD. MiR-195-5p was the regulatory miRNA upstream of E2F7, and lowly expressed in LUAD. The cell experiments suggested that E2F7 advanced the DDP resistance of LUAD cells by repressing DNA damage. Finally, the rescue assay manifested that miR-195-5p overexpression could abate inhibition of E2F7 overexpression on the DNA damage and the DDP sensitivity of LUAD cells. MiR-195-5p raised the DDP sensitivity of LUAD cells by advancing the DNA damage in LUAD cells via inhibition of E2F7.

E2F2 Reprograms Macrophage Function By Modulating Material and Energy Metabolism in the Progression of Metabolic Dysfunction-Associated Steatohepatitis.

Macrophages are essential for the development of steatosis, hepatic inflammation, and fibrosis in metabolic dysfunction-associated steatohepatitis(MASH). However, the roles of macrophage E2F2 in the progression of MASH have not been elucidated. This study reveals that the expression of macrophage E2F2 is dramatically downregulated in MASH livers from mice and humans, and that this expression is adversely correlated with the severity of the disease. Myeloid-specific E2F2 depletion aggravates intrahepatic inflammation, hepatic stellate cell activation, and hepatocyte lipid accumulation during MASH progression. Mechanistically, E2F2 can inhibit the SLC7A5 transcription directly. E2F2 deficiency upregulates the expression of SLC7A5 to mediate amino acids flux, resulting in enhanced glycolysis, impaired mitochondrial function, and increased macrophages proinflammatory response in a Leu-mTORC1-dependent manner. Moreover, bioinformatics analysis and CUT &Tag assay identify the direct binding of Nrf2 to E2F2 promoter to promote its transcription and nuclear translocation. Genetic or pharmacological activation of Nrf2 effectively activates E2F2 to attenuate the MASH progression. Finally, patients treated with CDK4/6 inhibitors demonstrate reduced E2F2 activity but increased SLC7A5 activity in PBMCs. These findings indicated macrophage E2F2 suppresses MASH progression by reprogramming amino acid metabolism via SLC7A5- Leu-mTORC1 signaling pathway. Activating E2F2 holds promise as a therapeutic strategy for MASH.

Profiling mRNA and miRNA expression variations associated with cyclin-dependent kinase pathway in the low-grade luminal early breast cancer.

Luminal A and B subtypes of breast tumors have fluctuated in proliferation rates, which arise from cell cycle dysregulation in cancer. Besides, microRNAs can regulate various cell processes through integration with mRNA. miRNAs that target the cell cycle are significant because of their prediction capability of prognosis. The objective of this study is to discover the integration between miRNA-mRNA and miRNA-miRNA related to cyclin-dependent kinase. Thirty-four pairs of human primary breast cancer and tumor margin samples from luminal breast cancer patients were investigated to assess the expression levels of CCND1, E2F1, miR-124, miR-503, miR-449a, and miR-449b. Afterward, the expression levels of mRNAs and miRNAs were investigated by real-time PCR. Statistical analysis was conducted to compare the expression levels between breast cancer and corresponding normal tissues. The protein expressions of E2F1 and CCND1 were verified by western blotting. Further, the correlation between mRNAs and miRNAs was calculated. E2F1 was significantly increased in both luminal A and B patients, while CCND1 was upregulated only in luminal B. Significant differences in all miRNAs were detected in both luminal A and B biopsy specimens (p < 0.0001). The correlation analysis revealed a positive strong correlation between miR-124 and E2F1 in luminal A patient. Moreover, the correlation test confirmed the ability of miR-449a to increase the CCND1 gene in luminal B subtypes. Also, miRNA correlation exhibited the miRNA-miRNA interaction in luminal breast cancer. This study demonstrated the novel miRNA-mRNA and miRNA-miRNA interactions, providing new insights into the molecular integration in luminal A and B patients. The authors propose that this research could contribute to introducing valuable biomarkers for luminal cancerous cells.

Regular exercise suppresses steatosis-associated liver cancer development by degrading E2F1 and c-Myc via circadian gene upregulation.

Regular exercise is believed to suppress cancer progression. However, the precise molecular mechanisms by which exercise prevents cancer development remain unclear. In this study, using a steatosis-associated liver cancer mouse model, we found that regular exercise at a speed of 18 m/min for 20 min daily suppressed liver cancer development. To explore the underlying mechanisms, we examined the gene expression profiles in the livers of the exercise and non-exercise groups. The expressions of circadian genes, such as Per1 and Cry2, were upregulated in the exercise group. As circadian rhythm disruption is known to cause various diseases, including cancer, improving circadian rhythm through exercise could contribute to cancer prevention. We further found that the expression of a series of E2F1 and c-Myc target genes that directly affect the proliferation of cancer cells was downregulated in the exercise group. However, the expression of E2F1 and c-Myc was transcriptionally unchanged but degraded at the post-translational level by exercise. Cry2, which is regulated by the Skp1-Cul1-FBXL3 (SCFFBXL3) ubiquitin ligase complex by binding to FBXL3, can form a complex with E2F1 and c-Myc, which we think is the mechanism to degrade them. Our study revealed a previously unknown mechanism by which exercise prevents cancer development.

PHF10 inhibits gastric epithelium differentiation and induces gastric cancer carcinogenesis.

Gastric cancer (GC) is characterized with differentiation disorders, the precise mechanisms of which remain unknown. Our previous study showed that PHF10 exhibits oncogenic properties in GC, with its histological presentation indicating a potential role in the modulation of differentiation disorders in GC. This study reveals a significant upregulation of PHF10 in GC tissues, showing a negative correlation with differentiation level. PHF10 was found to impede the differentiation of GC cells while promoting their stemness properties. This was attributed to the formation of a positive feedback loop between PHF10 and E2F1, resulting in dysregulated expression levels in GC. Additionally, PHF10 was found to mediate the transcriptional repression of the target gene DUSP5 in GC cells through the assembly of the SWI/SNF complex, leading to an elevation in pERK1/2 levels. In GC tissues, a negative association was noted between the expression of E2F1 or PHF10 and DUSP5, whereas a positive correlation was observed between the expression of E2F1 or PHF10 and pERK1/2. Additional rescue experiments confirmed that the inhibitory effect on differentiation of GC cells by PHF10 is dependent on the DUSP5-pERK1/2 axis. The signaling cascade involving E2F1-PHF10-DUSP5-pERK1/2 was identified as an important player in regulating differentiation and stemness in GC cells. PHF10 emerges as a promising target for differentiation induction therapy in GC.

LOCC: a novel visualization and scoring of cutoffs for continuous variables with hepatocellular carcinoma prognosis as an example

BackgroundThe interpretation of large datasets, such as The Cancer Genome Atlas (TCGA), for scientific and research purposes, remains challenging despite their public availability. In this study, we focused on identifying gene expression profiles most relevant to patient prognosis and aimed to develop a method and database to address this issue. To achieve this, we introduced Luo’s Optimization Categorization Curve (LOCC), an innovative tool for visualizing and scoring continuous variables against dichotomous outcomes. To demonstrate the efficacy of LOCC using real-world data, we analyzed gene expression profiles and patient data from TCGA hepatocellular carcinoma samples.ResultsTo showcase LOCC, we demonstrate an optimal cutoff for E2F1 expression in hepatocellular carcinoma, which was subsequently validated in an independent cohort. Compared to ROC curves and their AUC, LOCC offered a superior description of the predictive value of E2F1 expression across various cancer types. The LOCC score, comprised of factors representing significance, range, and impact of the biomarker, facilitated the ranking of all gene expression profiles in hepatocellular carcinoma, aiding in the evaluation and understanding of previously published prognostic gene signatures. We also demonstrate that LOCC does not have the same assumptions required of Cox proportional hazards modeling for accurate analysis. Repeated sampling demonstrated that LOCC scores outperformed ROC’s AUC in discriminating predictors from non-predictors. Additionally, gene set enrichment analysis revealed significant associations between certain genes and prognosis, such as E2F target genes and G2M checkpoint with poor prognosis, and bile acid metabolism and oxidative phosphorylation with good prognosis.ConclusionIn summary, we present LOCC as a novel visualization tool for the analysis of gene expression in cancer, particularly for understanding and selecting cutoffs. Our findings suggest that LOCC scores, which effectively rank genes based on their prognostic potential, represent a more suitable approach than ROC curves and Cox proportional hazard for prognostic modeling and understanding in cancer gene expression analysis. LOCC holds promise as an invaluable tool for advancing precision medicine and furthering biomarker research. Further research regarding multivariable integration and validation will help LOCC reach its full potential and establish its utility across diverse cancer types and clinical settings.Graphical abstract

Deubiquitylase USP31 Induces Autophagy and Promotes the Progression in Lung Squamous Cell Carcinoma Cells by Stabilizing E2F1 Expression.

Autophagy exerts a vital role in the progression of lung squamous cell carcinoma (LUSC). Ubiquitin-specific peptidase 31 (USP31) has recently been found to be involved in the development of a variety of cancers. However, whether USP31 modulates autophagy in LUSC remains unclear. This study revealed that high levels of USP31 were discovered in LUSC tissue samples employing the Gene Expression Profiling Interactive Analysis (GEPIA) database, quantitative real- time PCR (qRT-PCR), and Western blot analysis. Cell proliferation was tested via cell counting kit 8 (CCK-8) as well as colony formation, demonstrating that USP31-stable knockdown reduced cell viability. Immunofluorescence analysis illustrated that USP31 knockdown blocked the occurrence of LUSC autophagy. Meanwhile, USP31 has been shown to stabilize the expression of E2F transcription factor 1 (E2F1) through the proteasome pathway. Furthermore, overexpressed E2F1 effectively eliminated the effect of USP31 knockdown on LUSC cell proliferation and autophagy. In summary, this investigation proved that USP31 promoted LUSC cell growth and autophagy, at least in part by stabilizing E2F1 expression, which provided a potential therapeutic gene for the treatment of LUSC.

The novel circFKBP8/miR-432-5p/E2F7 cascade functions as a regulatory network in breast cancer

BackgroundCircular RNAs (circRNAs) are capable of affecting breast cancer (BC) development. However, the role and underneath mechanism of circFKBP8 (also known as hsa_circ_0000915) in BC remain largely unknown.MethodsExpression analyses were performed using quantitative real-time polymerase chain reaction (qRT-PCR), western blot, and immunohistochemistry (IHC) assays. Effects on cell functional phenotypes were determined by assessing cell proliferation, migratory capacity, invasion, and stemness in vitro. The relationship between microRNA (miR)-432-5p and circFKBP8 or E2F transcription factor 7 (E2F7) was examined by RNA pull-down, dual-luciferase reporter, and RNA immunoprecipitation (RIP) assays. Xenograft assays were used to identify the function of circFKBP8 in vivo.ResultsCircFKBP8 was presented at high levels in BC tissues and cells. High circFKBP8 expression was associated with worse overall survival in BC patients. CircFKBP8 suppression inhibited BC cell proliferation, migratory capacity, invasion and stemness in vitro. CircFKBP8 suppression blocked xenograft tumor growth in vivo. Mechanistically, circFKBP8 functioned as a miR-432-5p sponge to modulate E2F7 expression. CircFKBP8 modulated BC cell malignant behaviors by miR-432-5p, and miR-432-5p affected these cell phenotypes through E2F7.ConclusionOur observations prove that circFKBP8 promotes BC malignant phenotypes through the miR-432-5p/E2F7 cascade, offering a promising therapeutic and prognostic target for BC.

Relationship Between Changes in the Expression Levels of miR-134 and E2F6 in Mediating Control of Apoptosis in NMDA-Induced Glaucomatous Mice

Objective This investigation was to determine the relationship between changes in the expression levels of miR-134 and the E2F transcription factor 6 (E2F6) in mediating control of apoptosis in N-methyl-D-aspartate (NMDA)-induced glaucomatous mice. Methods Morphological and structural changes were quantitatively analyzed along with apoptosis in the retinal ganglion cell (RGC) layer, internal plexiform layer and RGCs. Glaucomatous RGCs were transfected, and cell viability and apoptosis were examined. The targeting relationship between miR-134 and E2F6 was analyzed, as well as their expression pattern. Results Intravitreal injection of NMDA induced a significant reduction in the number of RGCs and thinning of IPL thickness. miR-134 was highly expressed and E2F6 was lowly expressed in glaucoma mice. Suppression of miR-134 or E2F6 overexpression inhibited apoptosis in the glaucomatous RGCs and instead their proliferative activity. MiR-134 targeted inhibition of E2F6 expression. Suppressing rises in E2F6 expression reduced the interfering effect of miR-134 on glaucomatous RGC development. Conclusion Depleting miR134 expression increases, in turn, E2F6 expression levels and in turn reduces glaucomatous RGC apoptosis expression.

ARHGEF39 targeted by E2F1 fosters hepatocellular carcinoma metastasis by mediating fatty acid metabolism

BackgroundHepatocellular carcinoma (HCC) stands as the prevailing manifestation of primary liver cancer. Previous studies have implicated ARHGEF39 in various cancer progression processes, but its impact on HCC metastasis remains unclear. MethodsBioinformatics analysis and qRT-PCR were employed to test ARHGEF39 expression in HCC tissues and cells, identified enriched pathways associated with ARHGEF39, and investigated its regulatory relationship with E2F1. The impact of ARHGEF39 overexpression or knockdown on cellular phenotypes in HCC was assessed through the implementation of CCK-8 and Transwell assays. Accumulation of neutral lipids was determined by BODIPY 493/503 staining, while levels of triglycerides and phospholipids were measured using specific assay kits. Expression of E-cadherin, Vimentin, MMP-2, MMP-9, and FASN were analyzed by Western blot. The interaction between ARHGEF39 and E2F1 was validated through ChIP and dual-luciferase reporter assays. ResultsOur study demonstrated upregulated expression of both ARHGEF39 and E2F1 in HCC, with ARHGEF39 being associated with fatty acid metabolism (FAM) pathways. Additionally, ARHGEF39 was identified as a downstream target gene of E2F1. Cell-based experiments unmasked that high expression of ARHGEF39 mediated the promotion of HCC cell viability, migration, and invasion via enhanced FAM. Moreover, rescue assays demonstrated that the promotion of HCC cell metastasis by high ARHGEF39 expression was attenuated upon treatment with Orlistat. Conversely, the knockdown of E2F1 suppressed HCC cell metastasis and FAM, while the upregulation of ARHGEF39 counteracted the repressive effects of E2F1 downregulation on the metastatic potential of HCC cells. ConclusionOur findings confirmed the critical role of ARHGEF39 in HCC metastasis and unmasked potential molecular mechanisms through which ARHGEF39 fostered HCC metastasis via FAM, providing a theoretical basis for exploring novel molecular markers and preventive strategies for HCC metastasis.

ZFP36L1 and ZFP36L2 reduce cyclin D1 expression by decreasing expression of E2F1 and long 3'UTR isoform of CCND1 transcripts.

The CCND1 mRNA possesses at least two distinct lengths of the 3'-untranslated region (3'UTR), with the long isoform containing multiple AU-rich elements (AREs). The tandem zinc finger (TZF) domains of human ZFP36 family members have the capacity to bind to AREs and promote mRNA degradation. Our previous study demonstrated that mutations in the TZF domain of ZFP36L1 or ZFP36L2 increased the CCND1 expression. In this study, we investigated whether ZFP36L1 and ZFP36L2 could downregulate the expression of the long 3'UTR isoform of CCND1 mRNA in human colorectal cancer (CRC) cells. Firstly, the Gene Expression Profiling Interactive Analysis 2 database indicated downregulation of ZFP36 and ZFP36L1, while E2F1 and CCND1 were upregulated in human CRC tissues compared to normal colorectal tissues. Overexpression of ZFP36L1 and/or ZFP36L2 in T-REx-293, DLD-1, and HCT116 cells led to a decrease in the total CCND1, long isoform ratio of CCND1 mRNA, and E2F1 expression. Conversely, knockdown of ZFP36L1 and ZFP36L2 in HCT116 cells resulted in an increase in total CCND1, long isoform ratio of CCND1 mRNA, and E2F1 expression. Knockdown of E2F1 decreased CCND1 expression, indicating a potential role for E2F1 in regulating CCND1 expression at the transcriptional level. These findings suggest that ZFP36L1 and ZFP36L2 play a negative role in CCND1 expression. The underlying mechanisms might involve the reduction of E2F1 transactivation at the transcriptional level and the promotion of AREs-mediated decay of the long 3'UTR isoform of CCND1 through posttranscriptional processes.

A testis-specific lncRNA functions as a post-transcriptional regulator of MDM2 and stimulates apoptosis of testicular germ cell tumor cells

Germ cells preferentially induce apoptosis in response to DNA damage to avoid genomic mutations. Apoptosis of germ cells is closely related to cancer development and chemotherapy resistance; however, its regulatory mechanism is unclear. Here, we suggest that testis-specific lncRNA LINC03074 is involved in male germ cell apoptosis by regulating the expression of the proto-oncogene MDM2. LINC03074 is highly expressed in the sperm of healthy adult testes and cancer cells of testes with testicular germ cell tumors (TGCTs). LINC03074 binds to MDM2 mRNA via an Alu element, thereby reducing MDM2 protein levels. LINC03074 stimulates STAU1-mediated nuclear export of MDM2 mRNA by increasing STAU1 binding to MDM2 mRNA in the cell nucleus, thereby promoting PKR-mediated translational repression in the cytoplasm. The induction of apoptosis in TGCT cells and their responsiveness to the anticancer drug cisplatin is enhanced by LINC03074. Notably, LINC03074 increased E2F1 expression without increasing p53, the primary target of MDM2, and upregulated the apoptotic gene p73, the target gene of E2F1. LINC03074-mediated regulation of apoptosis contributes to the responsiveness of TGCTs to anticancer drug-induced DNA damage.

AB045. E2F6 promotes temozolomide resistance in glioblastoma by enrichment in CARD6 and POSTN promoter region.

Glioblastoma (GBM) is the most aggressive primary malignant brain tumor. Temozolomide (TMZ) is the most used first-line chemotherapeutic agent for GBM after surgery, but acquired resistance to TMZ frequently leads to treatment failure and is a major challenge in the clinical treatment of GBM. Increasing evidence suggests that E2F transcription factor 6 (E2F6) is associated with a variety of tumor malignant biological behaviors and drug resistance, but its biological function and underlying molecular mechanisms in GBM are unknown. The study investigated the levels of E2F6 in both TMZ-sensitive and TMZ-resistant GBM cells and tissues using Western blotting and immunofluorescence assays. In vitro experiments were conducted to explore the impact of E2F6 on TMZ resistance and glioma stem cell stemness. These experiments included Western blotting, colony formation assay, flow cytometry assay, and TdT-mediated dUTP nick-end labeling (TUNEL) assay. Bioinformatic analyses were conducted to investigate the mechanism behind the high expression of E2F6 in TMZ-resistant cells and its correlation with caspase recruitment domain 6 (CARD6) and disulfide-linked cell adhesion protein (POSTN). The study employed bioinformatic analyses, messenger RNA (mRNA) sequencing, chromatin immunoprecipitation sequencing assay, immunofluorescence, quantitative real-time polymerase chain reaction (qRT-PCR), and Western blotting. To examine the function of E2F6, an intracranial xenograft tumor mouse model was used for in vivo experiments. It was found that CARD6 and POSTN were significantly associated with TMZ resistance and survival of GBM patients. E2F6 was up-regulated in TMZ-resistant cells and tissues. Knockdown of E2F6 down-regulated the expression of CARD6, promoted TMZ-induced apoptosis, and enhanced chemo-sensitivity, whereas its overexpression significantly increased TMZ resistance in vitro and in vivo. In addition, E2F6 can promote TMZ resistance through stem-like properties acquisition. We identified a signaling pathway related to E2F6 and POSTN, which maintains the self-renewal of GBM stem cells (GSCs). E2F6 concentrates in the promoter region of POSTN, thereby regulating the expression of GSCs-related genes cluster of differentiation 133 (CD133), Nestin, and sex-determining region Y-box 2 (SOX2), which may be involved in tumor metabolism and drug resistance processes. Down-regulation of E2F6 down-regulated the expression of POSTN and inhibited tumor growth in nude mice. These results suggest that the E2F6-CARD6/POSTN signaling axis regulates the malignant biological behaviors of GBM and TMZ resistance. These findings are expected to provide promising therapeutic targets for CARD6 overcoming GBM TMZ resistance.

Sustained cancer-relevant alternative RNA splicing events driven by PRMT5 in high-risk neuroblastoma.

Protein arginine methyltransferase 5 (PRMT5) is over-expressed in a wide variety of cancers and is implicated as having a key oncogenic role, achieved in part through its control of the master transcription regulator E2F1. We investigated the relevance of PRMT5 and E2F1 in neuroblastoma (NB) and found that elevated expression of PRMT5 and E2F1 occurs in poor prognosis high-risk disease and correlates with an amplified Myelocytomatosis viral-related oncogene, neuroblastoma-derived (MYCN) gene. Our results show that MYCN drives the expression of splicing factor genes that, together with PRMT5 and E2F1, lead to a deregulated alternative RNA splicing programme that impedes apoptosis. Pharmacological inhibition of PRMT5 or inactivation of E2F1 restores normal splicing and renders NB cells sensitive to apoptosis. Our findings suggest that a sustained cancer-relevant alternative RNA splicing programme desensitises NB cells to apoptosis, and identify PRMT5 as a potential therapeutic target for high-risk disease.

DNMT1-Mediated the Downregulation of FOXF1 Promotes High Glucose-induced Podocyte Damage by Regulating the miR-342-3p/E2F1 Axis.

Podocyte damage plays a crucial role in the occurrence and development of diabetic nephropathy (DN). Accumulating evidence suggests that dysregulation of transcription factors plays a crucial role in podocyte damage in DN. However, the biological functions and underlying mechanisms of most transcription factors in hyperglycemia-induced podocytes damage remain largely unknown. Through integrated analysis of data mining, bioinformatics, and RT-qPCR validation, we identified a critical transcription factor forkhead box F1 (FOXF1) implicated in DN progression. Moreover, we discovered that FOXF1 was extensively down-regulated in renal tissue and serum from DN patients as well as in high glucose (HG)-induced podocyte damage. Meanwhile, our findings showed that FOXF1 might be a viable diagnostic marker for DN patients. Functional experiments demonstrated that overexpression of FOXF1 strikingly enhanced proliferation, outstandingly suppressed apoptosis, and dramatically reduced inflammation and fibrosis in HG-induced podocytes damage. Mechanistically, we found that the downregulation of FOXF1 in HG-induced podocyte damage was caused by DNMT1 directly binding to FOXF1 promoter and mediating DNA hypermethylation to block FOXF1 transcriptional activity. Furthermore, we found that FOXF1 inhibited the transcriptional expression of miR-342-3p by binding to the promoter of miR-342, resulting in reduced sponge adsorption of miR-342-3p to E2F1, promoting the expression of E2F1, and thereby inhibiting HG-induced podocytes damage. In conclusion, our findings showed that blocking the FOXF1/miR-342-3p/E2F1 axis greatly alleviated HG-induced podocyte damage, which provided a fresh perspective on the pathogenesis and therapeutic strategies for DN patients.

HES6 Mediates Oxidative Phosphorylation Pathway to Promote Immune Infiltration of CD8 + T Cells in Lung Adenocarcinoma.

Tumor immunotherapy has recently gained popularity as a cancer treatment strategy. The molecular mechanism controlling immune infiltration in lung adenocarcinoma (LUAD) cells, however, is not well characterized. Investigating the immune infiltration modulation mechanism in LUAD is crucial. LUAD patient samples were collected, and HES6 expression and immune infiltration level of CD8 + T cells in patient tissues were analyzed. Bioinformatics was utilized to identify binding relationship between E2F1 and HES6, and enrichment pathway of HES6. The binding of E2F1 to HES6 was verified using dual-luciferase and ChIP experiments. HES6 and E2F1 expression in LUAD cells was detected. LUAD cells were co-cultured with CD8 + T cells, and the CD8 + T cell killing level, IFN-γ secretion, and CD8 + T-cell chemotaxis level were measured. Expression of key genes involved in oxidative phosphorylation was detected, and the oxygen consumption rate of LUAD cells was assessed. A mouse model was constructed to assay Ki67 expression and apoptosis in tumor tissue. High expression of HES6 promoted CD8 + T-cell infiltration and enhanced T-cell killing ability through oxidative phosphorylation. Further bioinformatics analysis, molecular experiments, and cell experiments verified that E2F1 negatively regulated HES6 by oxidative phosphorylation, which suppressed CD8 + T-cell immune infiltration. In addition, in vivo assays illustrated that silencing HES6 repressed tumor cell immune evasion. E2F1 inhibited HES6 transcription, thereby mediating oxidative phosphorylation to suppress immune infiltration of CD8 + T cells in LUAD. The biological functions and signaling pathways of these genes were analyzed, which may help to understand the possible mechanisms regulating immune infiltration in LUAD.

The role of circHmbox1(3,4) in ferroptosis-mediated cognitive impairments induced by manganese

Excessive environmental exposure to manganese (Mn) has been linked to cognitive impairments, circular RNAs (circRNAs) have been recognized for their roles in epigenetic regulation in various biological processes, including neurological pathogenesis. Previous studies found that ferroptosis, an iron ion-dependent programmed cell death, may be involved in cognitive impairments. However, specific mechanisms underlying the relationship among circRNA, ferroptosis, and neurotoxicity of Mn are not well-understood. In the current study, RNA sequencing was performed to profile RNA expression in Neuro-2a (N2a) cells that were treated with 300 μM Mn. The potential molecular mechanisms of circHmbox1(3,4) in Mn-induced cognitive impairments were investigated via various experiments, such as Western blot and intracerebroventricular injection in mice. We observed a significant decrease in the expression of circHmbox1(3,4) both in vitro and in vivo following Mn treatment. The results of Y maze test and Morris water maze test demonstrated an improvement in learning and memory abilities following circHmbox1(3,4) overexpression in Mn treated mice. Mn treatment may reduce circHmbox1(3,4) biogenesis through lowered expression of E2F1/QKI. Inhibiting circHmbox1(3,4) expression led to GPX4 protein degradation through protein ligation and ubiquitination. Overall, the current study showed that Mn exposure-induced cognitive dysfunction may be mediated through ferroptosis regulated by circHmbox1(3,4).