The Role and Clinical Implications of the Retinoblastoma (RB)-E2F Pathway in Gastric Cancer

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.

The structure and function of multifunctional protein ErbB3 binding protein 1 (Ebp1) and its role in diseases

ErbB3-binding protein 1(Ebp1) has two isoforms, p42 Ebp1 and p48 Ebp1, both of which can regulate cell growth and differentiation. But these isoforms often have opposite effects, including contradictory roles in regulation of cell growth in different tissues and cells. P48 Ebp1 belongs to the full-length sequence, while conformational changes in the crystal structure of p42 Ebp1 reveals a lack of an α helix at the amino terminus. Due to the differences in the structures of these two isoforms, they have different binding partners and protein modifications. Ebp1 can function as both an oncogene and a tumor suppressor factor. However, the underlying mechanisms by which these two isoforms exert opposite functions are still not fully understood. In this review, we summarize the genes and the structures of protein of these two isoforms, protein modifications, binding partners and the association of different isoforms with diseases.

Working title: Molecular involvement of p53-MDM2 interactome in gastrointestinal cancers

The interaction between murine double minute 2 (MDM2) and p53, marked by transcriptional induction and feedback inhibition, orchestrates a functional loop dictating cellular fate. The functional loop comprising p53-MDM2 axis is made up of an interactome consisting of approximately 81 proteins, which are spatio-temporally regulated and involved in DNA repair mechanisms. Biochemical and genetic alterations of the interactome result in dysregulation of the p53-mdm2 axis that leads to gastrointestinal (GI) cancers. A large subset of interactome is well known and it consists of proteins that either stabilize p53 or MDM2 and proteins that target the p53-MDM2 complex for ubiquitin-mediated destruction. Upstream signaling events brought about by growth factors and chemical messengers invoke a wide variety of posttranslational modifications in p53-MDM2 axis. Biochemical changes in the transactivation domain of p53 impact the energy landscape, induce conformational switching, alter interaction potential and could change solubility of p53 to redefine its co-localization, translocation and activity. A diverse set of chemical compounds mimic physiological effectors and simulate biochemical modifications of the p53-MDM2 interactome. p53-MDM2 interactome plays a crucial role in DNA damage and repair process. Genetic aberrations in the interactome, have resulted in cancers of GI tract (pancreas, liver, colorectal, gastric, biliary, and esophageal). We present in this article a review of the overall changes in the p53-MDM2 interactors and the effectors that form an epicenter for the development of next-generation molecules for understanding and targeting GI cancers.

E2F1 promotes cell migration in hepatocellular carcinoma via FNDC3B

FNDC3B (fibronectin type III domain containing 3B) is highly expressed in hepatocellular carcinoma (HCC) and other cancer types, and fusion genes involving FNDC3B have been identified in HCC and leukemia. Growing evidence suggests the significance of FNDC3B in tumorigenesis, particularly in cell migration and tumor metastasis. However, its regulatory mechanisms remain elusive. In this study, we employed bioinformatic, gene regulation, and protein-DNA interaction screening to investigate the transcription factors (TFs) involved in regulating FNDC3B. Initially, 338 candidate TFs were selected based on previous chromatin immunoprecipitation (ChIP)-seq experiments available in public domain databases. Through TF knockdown screening and ChIP coupled with Droplet Digital PCR assays, we identified that E2F1 (E2F transcription factor 1) is crucial for the activation of FNDC3B. Overexpression or knockdown of E2F1 significantly impacts the expression of FNDC3B. In conclusion, our study elucidated the mechanistic link between FNDC3B and E2F1. These findings contribute to a better understanding of FNDC3B in tumorigenesis and provide insights into potential therapeutic targets for cancer treatment.

The association of E2F1 and E2F2 single nucleotide polymorphisms with laryngeal squamous cell carcinoma pathomorphological features

BACKGROUND

Laryngeal squamous cell carcinoma (LSCC) is one of the most common types of cancer in the upper respiratory tract. It is well-known that it has a high mortality rate and poor prognosis in advanced stages. There are well-known risk factors for LSCC, though new specific and prognostic blood-based markers for LSCC development and prognosis are essential. The current study aimed to evaluate the impact of four different single nucleotide polymorphisms (SNPs), E2F1 (rs3213183 and rs3213180) and E2F2 (rs2075993 and rs3820028), on LSCC development, morphological features, and patient 5-year survival rate.

METHODS

A total of 200 LSCC patients and 200 controls were included in this study; both groups were matched by age and sex. In the present study, we analyzed four single nucleotide polymorphisms (SNPs) in the genes E2F1 (rs3213183 and rs3213180) and E2F2 (rs2075993 and rs3820028) and evaluated their associations with the risk of LSCC development, its clinical and morphological manifestation, and patients 5-year survival rate. Genotyping was carried out using RT-PCR.

RESULTS

None of the analyzed SNPs showed a direct association with LSCC development. E2F2 rs2075993 G allele carriers (OR = 4.589, 95% CI 1.050-20.051, p = 0.043) and rs3820028 A allele carriers (OR = 4.750, 95% CI 1.088-20.736, p = 0.038) had a statistically significantly higher risk for poor differentiated or undifferentiated LSCC than non-carriers. E2F1 rs3213180 GC heterozygotes were found to have a 3.7-fold increased risk for lymph node involvement (OR = 3.710, 95% CI 1.452-9.479, p = 0.006). There was no statistically significant association between investigated SNPs and patient 5-year survival rate.

CONCLUSIONS

The present study indicates that E2F2 rs2075993 and rs3820028 impact LSCC differentiation, whereas E2F1 rs3213180 - on lymph node involvement.

Exploring Key Biomarkers and Common Pathogenesis of Seven Digestive System Cancers and Their Correlation with COVID-19

Digestive system cancer and COVID-19 significantly affect the digestive system, but the mechanism of interaction between COVID-19 and the digestive system cancers has not been fully elucidated. We downloaded the gene expression of COVID-19 and seven digestive system cancers (oral, esophageal, gastric, colorectal, hepatocellular, bile duct, pancreatic) from GEO and identified hub differentially expressed genes. Multiple verifications, diagnostic efficacy, prognostic analysis, functional enrichment and related transcription factors of hub genes were explored. We identified 23 common DEGs for subsequent analysis. CytoHubba identified nine hub genes (CCNA2, CCNB1, CDKN3, ECT2, KIF14, KIF20A, KIF4A, NEK2, TTK). TCGA and GEO data validated the expression and excellent diagnostic and prognostic ability of hub genes. Functional analysis revealed that the processes of cell division and the cell cycle were essential in COVID-19 and digestive system cancers. Furthermore, six related transcription factors (E2F1, E2F3, E2F4, MYC, TP53, YBX1) were involved in hub gene regulation. Via in vitro experiments, CCNA2, CCNB1, and MYC expression was verified in 25 colorectal cancer tissue pairs. Our study revealed the key biomarks and common pathogenesis of digestive system cancers and COVID-19. These may provide new ideas for further mechanistic research.

In Silico and Experimental Analyses of Long Non-coding RNA TMPO-AS1 Expression in Iranian Patients with Gastric Cancer

Background: In recent decades, many long non-coding RNAs (lncRNAs) have been reported to play a prominent role in tumorigenesis and the progression of human cancers, including gastric cancer (GC), a leading cause of cancer death in Iranian men and women. Studies have demonstrated that thymopoietin antisense transcript 1 (TMPO-AS1) was upregulated in different cancers by acting as an oncogenic lncRNA. Objectives: This study aimed to evaluate the expression of lncRNA TMPO-AS1 in Iranian patients with GC. Methods: In order to conduct the present study, 40 gastric tumor samples and 40 marginal noncancerous counterparts were collected. The characteristics of patients’ samples were recorded, and the TMPO-AS1 expression levels were evaluated by qRT-PCR analysis. The Cancer Genome Atlas (TCGA) data for TMPO-AS1 were used and analyzed through GEPIA and TANRIC online tools. Receiver operating characteristic (ROC) curve analysis was used to estimate the diagnostic value. Student t-test, one-way ANOVA, and chi-square test were accomplished via SPSS software. Results: Our data demonstrated that TMPO-AS1 was overexpressed in cancerous tissues compared to adjacent nonmalignant ones (P = 0.0076). None of the demographic and clinicopathological data were associated with TMPO-AS1 expression levels. The TCGA data demonstrated that TMPO-AS1 was upregulated in GC tissues in comparison to adjacent nonmalignant ones (P = 0.001). ROC curve analysis suggested that TMPO-AS1 expression levels could discriminate GC tumor tissues from normal ones (AUC = 0.699, P = 0.001). Conclusions: Altogether, in our study, we demonstrated that lncRNA TMPO-AS1 may be considered a biomarker in Iranian patients with GC. However, further investigations are required to confirm the potential application of this lncRNA in diagnosis, prognosis, and therapeutic applications of GC.

Cancer immunotherapies: A hope for the uncurable?

The use of cancer immunotherapies is not novel but has been used over the decades in the clinic. Only recently have we found the true potential of stimulating an anti-tumor response after the breakthrough of checkpoint inhibitors. Cancer immunotherapies have become the first line treatment for many malignancies at various stages. Nevertheless, the clinical results in terms of overall survival and progression free survival were not as anticipated. Majority of cancer patients do not respond to immunotherapies and the reasons differ. Hence, further improvements for cancer immunotherapies are crucially needed. In the review, we will discuss various forms of cancer immunotherapies that are being tested or already in the clinic. Moreover, we also highlight future directions to improve such therapies.

Epstein-Barr virus miR-BART2-5p and miR-BART11-5p regulate cell proliferation, apoptosis, and migration by targeting RB and p21 in gastric carcinoma

Epstein-Barr virus (EBV) was the first tumor virus discovered in humans and can cause various types of tumors. Molecular classification suggests that EBV-associated gastric cancer (EBVaGC) is a unique subtype of gastric cancer.EBV was also the first virus found to encode its own microRNAs. However, the functions of many miRNAs remain unknown. This study investigated the roles and targets of miR-BART2-5p (BART2-5p) and miR-BART11-5p (BART11-5p) in EBVaGC. The expression of RB and p21 in EBVaGC and EBV negative GC (EBVnGC) cells was evaluated by western blotting. Expression of BART2-5p and BART11-5p in EBVaGC cells was evaluated by droplet digital PCR. The effects of BART2-5p or BART11-5p and their potential mechanisms were further investigated using cell counting kit-8, colony formation assay, flow cytometry analysis, and transwell assay. BART2-5p and BART11-5p were abundantly expressed and RB and p21 were downregulated in EBVaGC cells. BART2-5p regulates RB and p21 expression by directly targeting them. BART11-5p regulates RB expression by directly targeting RB. Both BART2-5p and BART11-5p promoted proliferation and migration of gastric cancer cells, while inhibiting apoptosis and promoting S-phase arrest of the cell cycle. Thus, BART2-5p and BART11-5p play important roles in promoting proliferation and migration, and inhibiting apoptosis in EBVaGC by targeting RB and p21, thus providing new potential therapeutic targets for EBVaGC.

A novel ribociclib derivative WXJ-103 exerts anti-breast cancer effect through CDK4/6

The triple-negative breast cancer (TNBC) subtype is the most aggressive type of breast cancer with a low survival prognosis and high recurrence rate. There is currently no effective treatment to improve it. In this work, we explored the effect of a synthetic compound named WXJ-103 on several aspects of TNBC biology. The human breast cancer cell lines MDA-MB-231 and MCF-7 were used in the experiments, and the cell viability was detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method, and the cell migration and invasion abilities were detected by wound healing assay and Transwell invasion assay. Cell cycle and apoptosis experiments were analyzed by flow cytometry, and protein levels related to cyclin-dependent kinase (CDK) 4/6-cyclin D-Rb-E2F pathway were analyzed by western blotting. Then, in-vivo experiments were performed to determine the clinical significance and functional role of WXJ-103. The results show that WXJ-103 can inhibit the adhesion, proliferation, migration, and invasion of TNBC cells, and can arrest the cell cycle in G1 phase. The levels of CDK4/6-cyclin D-Rb-E2F pathway-related proteins such as CDK6 and pRb decreased in a dose-dependent manner. Therefore, the antitumor activity of WXJ-103 may depend on the inhibition of CDK4/6-cyclin D1-Rb-E2F pathway. This research shows that WXJ-103 may be a new promising antitumor drug, which can play an antitumor effect on TNBC and provide new ideas for the treatment of TNBC.

High Expression of E2F4 Is an Adverse Prognostic Factor and Related to Immune Infiltration in Oral Squamous Cell Carcinoma

Background

We aimed to evaluate the prognostic value of E2F4 expression in oral squamous cell carcinoma (OSCC) and clarify its influence on immune cell infiltration and biological functions.

Methods

The Cancer Genome Atlas (TCGA) database, the STRING database, and related online tools as well as single-sample gene set enrichment analysis (ssGSEA) were used for the analyses in our study.

Results

The E2F4 expression was elevated in OSCC tumor tissue compared with paracancerous tissues. The high expression of E2F4 was closely related to the poorer overall survival, disease-free survival, and progression-free interval of OSCC. In addition, pathway enrichment analyses revealed that the top 49 genes most closely related to E2F4 were strongly associated with the cell cycle. E2F4-related proteins were closely related to the following KEGG pathways: cell cycle, cellular senescence, PI3K-Akt signaling pathway, Wnt signaling pathway, and notch signaling pathway. It was also demonstrated that the E2F4 expression was negatively correlated with immune purity and strongly related to immune cell infiltration in OSCC.

Conclusions

E2F4 can be used as a novel biomarker for the diagnosis and prognosis of OSCC.

E2F1 promotes cell cycle progression by stabilizing spindle fiber in colorectal cancer cells

BACKGROUND

E2F1 is a transcription factor that regulates cell cycle progression. It is highly expressed in most cancer cells and activates transcription of cell cycle-related kinases. Stathmin1 and transforming acidic coiled-coil-containing protein 3 (TACC3) are factors that enhance the stability of spindle fiber.

METHODS

The E2F1-mediated transcription of transforming acidic coiled-coil-containing protein 3 (TACC3) and stathmin1 was examined using the Cancer Genome Atlas (TCGA) analysis, quantitative polymerase chain reaction (qPCR), immunoblotting, chromatin immunoprecipitation (ChIP), and luciferase reporter. Protein-protein interaction was studied using co-IP. The spindle structure was shown by immunofluorescence. Phenotype experiments were performed through MTS assay, flow cytometry, and tumor xenografts. Clinical colorectal cancer (CRC) specimens were analyzed based on immunohistochemistry.

RESULTS

The present study showed that E2F1 expression correlates positively with the expression levels of stathmin1 and TACC3 in colorectal cancer (CRC) tissues, and that E2F1 transactivates stathmin1 and TACC3 in CRC cells. Furthermore, protein kinase A (PKA)-mediated phosphorylation of stathmin1 at Ser16 is essential to the phosphorylation of TACC3 at Ser558, facilitating the assembly of TACC3/clathrin/α-tubulin complexes during spindle formation. Overexpression of Ser16-mutated stathmin1, as well as knockdown of stathmin1 or TACC3, lead to ectopic spindle poles including disorganized and multipolar spindles. Overexpression of wild-type but not Ser16-mutated stathmin1 promotes cell proliferation in vitro and tumor growth in vivo. Consistently, a high level of E2F1, stathmin1, or TACC3 not only associates with tumor size, lymph node metastasis, TNM stage, and distant metastasis, but predicts poor survival in CRC patients.

CONCLUSIONS

E2F1 drives the cell cycle of CRC by promoting spindle assembly, in which E2F1-induced stathmin1 and TACC3 enhance the stability of spindle fiber.

A Novel Gene Signature Associated With “E2F Target” Pathway for Predicting the Prognosis of Prostate Cancer

Background: The effect of the adenoviral early region 2 binding factors (E2Fs) target pathway on prostate cancer is not clear. It is necessary to establish an E2F target-related gene signature to predict prognosis and facilitate clinical decision-making.

Methods: An E2F target-related gene signature was established by univariate and LASSO Cox regression analyses, and its predictive ability was verified in multiple cohorts. Moreover, the enrichment pathway, immune microenvironment, and drug sensitivity of the activated E2F target pathway were also explored.

Results: The E2F target-related gene signature consisted of MXD3, PLK1, EPHA10, and KIF4A. The patients with high-risk scores showed poor prognosis, therapeutic resistance, and immunosuppression, along with abnormal growth characteristics of cells. Tinib drugs showed high sensitivity to the expression of MXD3 and EPHA10 genes.

Conclusion: Our research established an E2F target-related signature for predicting the prognosis of prostate cancer. This study provides insights into formulating individualized detection and treatment as well as provides a theoretical basis for future research.

High expression of ECT2 and E2F1 is associated with worse clinical manifestations and prognosis in patients with oral squamous cell carcinoma

To detect the expression, prognostic value, and possible effects of epithelial cell transforming sequence 2 (ECT2) and E2F1 in patients with oral squamous cell carcinoma (OSCC). Seventy subjects hospitalized for OSCC surgical treatment in the Fourth Hospital of Hebei Medical University were selected for this study. Expression levels of ECT2 and E2F1 were detected by qRT-PCR, Western blot, and immunohistochemistry. The Kaplan-Meier method and Cox risk proportional regression analysis were used to analyze the relationship between different expression levels of ECT2 or E2F1 and the survival of patients with OSCC in 3 years. Relative expression levels of E2F1 mRNA (1.31 ± 0.15) and ECT2 mRNA (3.95 ± 0.72) in OSCC tissues, compared to adjacent normal tissues (0.87 ± 0.11, 1.03 ± 0.23, all p < 0.05). ECT2 was highly expressed in 42 (60.00%) OSCC samples and E2F1 was highly expressed in 45 (64.29%) samples. The expression of ECT2 and E2F1 was related to clinical stage, lymphatic metastasis, tumor differentiation grade, and tumor diameter in OSCC patients. The higher the expression of ECT2 and E2F1, the lower the 3-year survival rate of patients. ECT2 high expression (HR=2.407, p < 0.001), E2F1 high expression of E2F1 (HR = 2.159, p = 0.013), Clinical stages (III+IV) (HR = 1.362, p = 0.012), medium and low differentiation (HR = 1.522, p = 0.015), lymphatic metastasis (HR = 1.951, p < 0.001), and tumor diameter (≥3 cm) (HR = 1.824, p = 0.002) could be independent factors for 3-year survival of patients with OSCC. The expression of ECT2 and E2F1 in OSCC was significantly up-regulated, which was closely related to clinical stage, lymph node metastasis, tumor size, and 3-year survival of OSCC patients.

Inhibition of HDACs Suppresses Cell Proliferation and Cell Migration of Gastric Cancer by Regulating E2F5 Targeting BCL2

(1) Background: Gastric cancer (GC) is the most common high death-rate cancer type worldwide, with an enhanced prevalence and increased rate of mortality. Although significant evidence on surgery strategy has been generated for the treatment of GC, conclusions are still uncertain regarding profound metastatic or persevering gastric cancer. Therefore, it is essential to develop novel and effective biomarkers or therapeutic targets for the diagnosis of GC. Histone deacetylations (HDACs) are important epigenetic regulators that control the aberrant transcription of critical genes that are mainly involved in cell proliferation, cell migration, regulation of the cell cycle, and different signal pathways. (2) Methods: Expression analysis of HDACs family members and E2F5 in gastric cancer cell lines was determined by RT-PCR and Western blotting. The cell proliferation was determined through an MTT assay. Cell migration was determined using a wound-healing assay. Flow cytometry experiments were used to determine cell-cycle analysis. The statistical software OriginPro 2015 (OriginLab, Northampton, MA, USA) was used to analyze data. A p value of < 0.05 was regarded as significant. (3) Results: The present study shows that E2F5 expression is upregulated in GC cancer cell lines compared to normal cell lines, and is positively associated with the level of HDACs and BCL2. HDACi and knocking down of E2F5 as tumor suppressors inhibited cell proliferation, migration invasion, and blocked the cell cycle in gastric cancer cells by suppressing BCL2. The results conclude that the anticancer mechanism of HDACi was determined by regulating E2F5 via targeting BCL2. (4) Conclusions: Our results suggest that the HDAC–E2F5–BCL2 signaling axis might be a novel potential biomarker in gastric cancer.