Effects of EIF3B gene downregulation on apoptosis and proliferation of human ovarian cancer SKOV3 and HO-8910 cells

N6-Methyladenosine Methylation of mRNA in Cell Apoptosis

Apoptosis, a highly controlled homeostatic mechanism that eliminates single cells without destroying tissue function, occurs during growing development and senescence. N6-methyladenosine (m6A), as the most common internal modification of eukaryotic mRNA, fine-tunes gene expression by regulating many aspects of mRNA metabolism, such as splicing, nucleation, stability, translation, and degradation. Remarkably, recent reports have indicated that aberrant methylation of m6A-related RNA may directly or indirectly influence the expression of apoptosis-related genes, thus regulating the process of cell apoptosis. In this review, we summarized the relationship between m6A modification and cell apoptosis, especially its role in the nervous system, and analyzed the limitations of the current research.

Nano-seq analysis reveals different functional tendency between exosomes and microvesicles derived from hUMSC

BACKGROUND

Extracellular vesicles (EVs) from human umbilical cord mesenchymal stem cells (hUMSCs) are widely considered to be the best mediators for cell-free therapy. An understanding of their composition, especially RNA, is particularly important for the safe and precise application of EVs. Up to date, the knowledge of their RNA components is limited to NGS sequencing and cannot provide a comprehensive transcriptomic landscape, especially the long and full-length transcripts. Our study first focused on the transcriptomic profile of hUMSC-EVs based on nanopore sequencing.

METHODS

In this study, different EV subtypes (exosomes and microvesicles) derived from hUMSCs were isolated and identified by density gradient centrifugation. Subsequently, the realistic long transcriptomic profile in different subtypes of hUMSC-EVs was systematically compared by nanopore sequencing and bioinformatic analysis.

RESULTS

Abundant transcript variants were identified in EVs by nanopore sequencing, 69.34% of which transcripts were fragmented. A series of full-length and long transcripts was also observed and showed a significantly higher proportion of intact or near-complete transcripts in exosomes than that in microvesicles derived from hUMSCs. Although the composition of RNA biotypes transported by different EV subtypes was similar, the distribution of transcripts and genes revealed the inter-heterogeneity and intra-stability between exosomes and microvesicles. Further, 85 different expressed transcripts (56 genes) and 7 fusion genes were identified. Pathway enrichment analysis showed that upregulated-expressed genes in microvesicles were mainly enriched in multiple neurodegenerative diseases, while upregulated-expressed genes in exosomes were mainly enriched in neutrophil extracellular trap formation, suggesting different functional tendencies of EV subtypes.

CONCLUSIONS

This study provides a novel understanding of different types of hUMSC-EVs, which not only suggests different transcriptome sorting mechanisms between exosomes and microvesicles, but also shows that different EV subtypes from the same source have different physiological functions, suggesting distinct clinical application prospects.

Eukaryotic translation initiation factor 3 subunit B could serve as a potential prognostic predictor for breast cancer

The EIF3 gene family is essential in controlling translation initiation during the cell cycle. The significance of the EIF3 subunits as prognostic markers and therapeutic targets in breast cancer is not yet clear. We analyzed the expression of EIF3 subunits in breast cancer on the GEPIA and Oncomine databases and compared their expression in breast cancer and normal tissues using BRCA data downloaded from TCGA. Then we performed clinical survival analysis on the Kaplan–Meier Plotter database and clinicopathologic analysis on the bc-genexMiner v4.1 database. And EIF3B was chosen for mutation analysis via the Cancer SEA online tool. Meanwhile, we performed the immunohistochemical assay, real-time RT-PCR, and Western blotting to analyze EIF3B expression levels in breast cancer. An EIF3B knockdown and a negative control cell line were conducted for MTT assay and cell cycle analysis to assess cell growth. Specifically, the results of TCGA and online databases demonstrated that upregulated EIF3B was associated with poorer overall and advanced tumor progression. We also confirmed that EIF3B was more highly expressed in breast cancer cells and tissues than normal and correlated with a worse outcome. And knockdown of EIF3B expression inhibited the cell cycle and proliferation. Furthermore, EIF3B was highly mutated in breast cancer. Collectively, our results suggested EIF3B as a potential prognostic marker and therapeutic target for breast cancer.

Knockdown of GBAS regulates esophageal cancer cell viability and apoptosis

Esophageal cancer (EC) is the sixth leading cause of cancer‑related mortality worldwide, with the incidence gradually increasing each year. Therefore, further clarifying the mechanism underlying the development of EC may be beneficial for identifying novel biomarkers and targets for its treatment. The present study aimed to determine the functional roles of glioblastoma‑amplified sequence (GBAS), a newly identified gene that has been reported to play crucial roles in multiple types of cancer, including in the malignant behavior of EC cells, such as cell viability, colony formation, cell apoptosis and cell cycle progression. The results of the present study revealed that, in vitro, the knockdown of GBAS significantly suppressed cell viability and colony formation in TE‑1 and KYSE‑150 cell lines, using a Celigo cell count analysis and colony formation assay respectively, whereas the apoptotic rate of EC cells was significantly increased by the knockdown of GBAS using Annexin V APC staining. Furthermore, following GBAS knockdown, the cell cycle progression of TE‑1 and KYSE‑150 cells was arrested in the G1 phase using PI staining. In conclusion, the findings of the present study suggested that GBAS may serve a role in EC by regulating cell viability, apoptosis and cell cycle progression.

Eukaryotic Translation Initiation Factor 3 Subunit B Is a Promoter in the Development and Progression of Pancreatic Cancer

Background: Pancreatic cancer (PC) is a malignant tumor with hidden incidence, high degree of malignancy, rapid disease progression, and poor prognosis. Eukaryotic translation initiation factor 3 subunit B (EIF3B) is necessary for tumor growth, which is an alternative therapeutic target for many cancers. However, little is known about the relationship between EIF3B and PC.

Methods: The expression of EIF3B in PC was detected by immunohistochemistry. EIF3B knockdown cell models were constructed by lentivirus infection. The MTT assay, the wound-healing assay, the transwell assay, the flow cytometry, and the Human Apoptosis Antibody Array was used to detect the effects of EIF3B knockdown on cell proliferation, cell migration, cell apoptosis, and cell cycle in vitro. Also, the effects of EIF3B knockdown on the tumor growth of PC were determined in vivo.

Results: This study showed that the expression level of EIF3B was significantly up-regulated in PC tumor tissues and associated with pathological grade. In vitro, EIF3B knockdown inhibited the PC cell proliferation and migration, and the apoptosis levels were obviously promoted by regulating apoptosis-related proteins including Bcl-2, HSP27, HSP60, Survivin, sTNF-R2, TNF-α, TNF-β, TRAILR-3, TRAILR-4, and XIAP. Furthermore, the tumor growth of PC was inhibited after the knockdown of EIF3B in vivo.

Conclusion: EIF3B was up-regulated in PC and was a promoter in the development and progression of PC, which could be considered as a therapeutic target for the treatment of PC.

EIF3B promotes cancer progression in pancreatic cancer

BACKGROUND

This study aimed to analyze the relative expression of Eukaryotic Translation Initiation Factor 3 Subunit B (EIF3B) in pancreatic cancer and elucidate its contribution to this disease.

METHODS

Relative expression of EIF3B in pancreatic cancer was analyzed by immunohistochemistry. Cell viability was determined by the MTT assay and cell proliferation was measured by direct cell counting. Cell apoptosis was detected by Annexin V staining followed by flow cytometry analysis, and cell cycle was analyzed by PI staining. The differential expression gene analysis was performed by microarray. Tumor progression in response to EIF3B deficiency in vivo was investigated using the xenograft tumor model.

RESULTS

We found aberrantly high expression of EIF3B in pancreatic cancer, which associated with unfavorable prognosis. Knockdown of EIF3B greatly compromised cell viability and proliferation in both SW1990 and PANC-1 cells. Furthermore, EIF3B deficiency induced cell cycle arrest and spontaneous apoptosis. In vivo tumor progression was significantly suppressed by EIF3B silencing in the xenograft mouse model. Mechanistically, we characterized down-regulation of CDH1 and IRS1 and up-regulation of DDIT3, PTEN and CDKN1B, in response to EIF3B knockdown, which might mediate the oncogenic effect of EIF3B in pancreatic cancer.

CONCLUSIONS

Our data uncovered the oncogenic role of EIF3B in pancreatic cancer.

SLC7A2 serves as a potential biomarker and therapeutic target for ovarian cancer

The solute carrier (SLC) family is the largest group of membrane transporters, but their functions in ovarian cancer (OV) remain unclear. We analyzed SLC family members with amino acids-transporting functions in OV. The mRNA expression levels and prognostic values of SLCs in OV were analyzed in the Gene Expression Profiling Interactive Analysis and Kaplan–Meier Plotter database. Solute carrier family 7 member 2 (SLC7A2), which showed differential expression and the most significant prognostic value, was selected for further analyses. The cBioPortal database, Gene Set Enrichment Analysis and Weighted Correlation Network Analysis were used to explore the potential functions and molecular mechanisms of SLC7A2 in OV. Validations in our own samples and in Gene Expression Omnibus datasets were conducted. Functional validation in OV cell lines was carried out. In total, 73 SLC family members were analyzed. Seven members were upregulated while 11 members were downregulated in OV and 15 members were protective factors for prognosis while 12 members were risk factors. SLC7A2 was downregulated in OV, and it was positively associated with prognosis. Knockdown of SLC7A2 promoted viability, invasion and migration of OV cells. These SLC family members and in particular SLC7A2 represented novel biomarkers for diagnosis and treatment for OV.

Eukaryotic translation initiation factor 3 subunit b is a novel oncogenic factor in prostate cancer

Prostate cancer, the second most common cancer among male adults, affects millions globally. We sought to investigate the expression and contribution of Eukaryotic translation initiation factor 3 subunit b (EIF3B) in prostate cancer. Expression of EIF3B was analyzed in both human prostate patient tissues and prostate cancer cell lines. Small interfering RNA (siRNA) knockdown of EIF3B was introduced into prostate cancer cell line PC-3 and LNCaP, followed by examination of cell viability, proliferation and apoptosis using the MTT, cell counting and terminal deoxynucleotidyl transferase dUTP nick end labeling assays, respectively. An in vivo xenograft tumor mouse model was employed to address the role of EIF3B in tumorigenesis as well. Finally, a gene microarray analysis was performed to search for differentially expressed genes upon EIF3B knockdown. EIF3B was upregulated in prostate tumor tissues and prostate cancer cell lines. EIF3B knockdown inhibited viability and proliferation of prostate cancer cells, as well as promoted cell apoptosis. In the in vivo mouse model, inoculation of EIF3B knockdown PC-3 cells displayed inhibited growth of xenograft tumors. In addition, potential signaling pathways that might be involved in EIF3B action in prostate cancer were identified by the gene microarray. EIF3B is a novel oncogenic factor in prostate cancer both in vitro and in vivo, which could be employed as a novel therapeutic target in the treatment against prostate cancer.

Eukaryotic initiation factor 3B is overexpressed and correlates with larger tumor size, advanced FIGO stage, and shorter overall survival in epithelial ovarian cancer patients

Background

This study aimed to detect the eukaryotic initiation factor 3B (EIF3B) expression and explore its correlation with clinical features and prognosis in epithelial ovarian cancer (EOC) patients.

Methods

A total of 230 primary EOC patients underwent surgery treatment were retrospectively reviewed. Immunohistochemical (IHC) assay was used to determine EIF3B expression in tumor and adjacent tissue specimens of all patients. According to the total IHC score, the expression of EIF3B was classified as low expression and high expression, and the latter was further divided into 3 grades: high+, high++, and high+++ expressions. Overall survival (OS) was calculated.

Results

Eukaryotic initiation factor 3B expression was increased in tumor tissue compared with adjacent tissue. Tumor EIF3B high expression correlated with larger tumor size (>10 cm), lymphatic metastasis, and advanced International Federation of Gynecology and Obstetrics stage (FIGO) (III/IV). Besides, OS was decreased in patients with tumor EIF3B high expression compared with patients with tumor EIF3B low expression, and further analysis showed that the OS was shortest in patients with tumor EIF3B high+++ expression, followed by patients with tumor EIF3B high++ expression and patients with tumor EIF3B high + expression, and the longest in patients with tumor EIF3B low expression. Additionally, higher tumor EIF3B expression, peritoneal cytology (positive), ascites volume (>100 mL), differentiation (poor vs. well/moderate), tumor size (>10 cm), FIGO stage (III/IV vs. I/II), and cancer antigen 125 (>1000 U/mL) independently predicted shorter OS.

Conclusion

Eukaryotic initiation factor 3B exhibits a clinical value for monitoring disease progression and predicting prognosis in EOC patients.

Expression of eukaryotic translation initiation factor 3 subunit B in liver cancer and its prognostic significance

Liver cancer is one of the major malignancies with the worst prognosis among all solid tumor types. It is therefore ponderable to explore prognostic biomarkers and therapeutic targets for liver cancer. Eukaryotic translation initiation factor 3 subunit B (EIF3B) is closely linked to the transcription initiation of cancer-associated genes. In the present study, EIF3B was indicated to be a potential prognostic biomarker of liver cancer. The mRNA expression level of EIF3B in liver cancer was assessed by analyzing the Cancer Genome Atlas dataset. χ² and Fisher's exact tests were used to assess the association of EIF3B expression with clinical parameters. Receiver-operating characteristic curve analysis was used for evaluating the diagnostic value of EIF3B. Overall and relapse-free survival were assessed using Kaplan-Meier curves to determine the association between EIF3B expression and survival. Univariate and multivariate Cox regression analysis were performed to identify the factors affecting overall/relapse-free survival. Gene set enrichment analysis (GSEA) was used to identify signaling pathways associated with EIF3B in liver cancer. It was revealed that EIF3B was highly expressed in liver cancer tissues and it had a promising diagnostic ability. Furthermore, the survival analysis indicated that patients with high EIF3B expression generally had shorter overall as well as relapse-free survival. Univariate and multivariate Cox analysis suggested that high EIF3B mRNA expression may serve as an independent biomarker for the prognostication of patients with liver cancer. GSEA suggested that MYC-V1 (HALLMARK_MYC_TARGETS_V1 geneset; P=0.009), MYC-V2 (HALLMARK_MYC_TARGETS_V2 geneset; P=0.004) and DNA repair pathways (HALLMARK_DNA_REPAIR geneset; P<0.001) were differentially enriched in high EIF3B expression and low EIF3B expression groups. In conclusion, high EIF3B expression was indicated to be an independent prognostic biomarker for patients with liver cancer.