Eukaryotic translation initiation factor 3B accelerates the progression of esophageal squamous cell carcinoma by activating β-catenin signaling pathway

EIF3B stabilizes PTGS2 expression by counteracting MDM2-mediated ubiquitination to promote the development and progression of malignant melanoma

Malignant melanoma (MM) is a neoplasm that develops from human melanocytes. It was reported that eukaryotic translation initiation factor 3 subunit B (EIF3B) is associated with multiple types of cancers, but its role in MM has not been reported. In the present study, we found that EIF3B was abundantly expressed in MM and was strongly related to lymphatic metastasis and pathological stage of MM patients. In addition, EIF3B depletion could block the progression of MM in vitro and in vivo. In contrast, EIF3B overexpression increased cell proliferation and migration in melanoma cells. More importantly, we identified that EIF3B's driver role in MM was mediated by PTGS2. In detail, we found that EIF3B stabilized PTGS2 expression by inhibiting PTGS2 ubiquitination, which is mediated by the E3 ligase MDM2. Moreover, like EIF3B, silencing PTGS2 could suppress MM development, and more interestingly, it could reverse the situation caused by overexpression of EIF3B in vitro and in vivo. Furthermore, the proliferation and migration inhibited by silencing of EIF3B were also partially recovered by overexpression of PTGS2. Overall, our findings revealed the potential of EIF3B as a therapeutic target for MM. Identification of EIF3B's function in MM may pave the way for future development of more specific and more effective targeted therapy strategies against MM.

The Role of m6A Modification and m6A Regulators in Esophageal Cancer

N6-methyladenosine (m6A) modification, the most prevalent RNA modification, is involved in all aspects of RNA metabolism, including RNA processing, nuclear export, stability, translation and degradation. Therefore, m6A modification can participate in various physiological functions, such as tissue development, heat shock response, DNA damage response, circadian clock control and even in carcinogenesis through regulating the expression or structure of the gene. The deposition, removal and recognition of m6A are carried out by methyltransferases, demethylases and m6A RNA binding proteins, respectively. Aberrant m6A modification and the dysregulation of m6A regulators play critical roles in the occurrence and development of various cancers. The pathogenesis of esophageal cancer (ESCA) remains unclear and the five-year survival rate of advanced ESCA patients is still dismal. Here, we systematically reviewed the recent studies of m6A modification and m6A regulators in ESCA and comprehensively analyzed the role and possible mechanism of m6A modification and m6A regulators in the occurrence, progression, remedy and prognosis of ESCA. Defining the effect of m6A modification and m6A regulators in ESCA might be helpful for determining the pathogenesis of ESCA and providing some ideas for an early diagnosis, individualized treatment and improved prognosis of ESCA patients.

Eukaryotic translation initiation factor 3 subunit B promotes head and neck cancer via CEBPB translation

Background

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer type worldwide. Deregulation of mRNA translation is a frequent feature of cancer. Eukaryotic translation initiation factor 3 subunit B (EIF3B) has been reported as an oncogene; however, its role in HNSCC has yet to be fully elucidated.

Methods

In this study, the clinical significance of EIF3B expression was analyzed based on TCGA datasets. Then, EIF3B expression was knocked down and its role in HNSCC was revealed. To explore the molecular mechanisms of EIF3B, we applied RNA sequencing and proteomics and acquired deregulated pathways. RNA immunoprecipitation (RIP) sequencing was conducted to reveal the target mRNAs of EIF3B, and TCGA datasets were used to validate potential targets of EIF3B.

Results

Elevated expression of EIF3B was observed in the HNSCC cancer samples. The expression of EIF3B was significantly correlated with the patient’s sex, age, HPV infection status, T stage, N stage, perineural invasion status and survival status. EIF3B serves as a marker of an unfavorable HNSCC prognosis. EIF3B-silenced Fadu and Cal27 cells exhibited reduced cell numbers, and EIF3B knockdown induced apoptosis in both cell lines. The EIF3B-silenced cells demonstrated decreased invasion and migration capabilities, and the EIF3B knockdown group mice showed significantly decreased tumor volumes. The results show that EIF3B promotes CEBPB translation and activates the MAPK pathway and revealed that IL6R and CCNG2 are targets of EIF3B-regulated CEBPB translation.

Conclusion

In summary, the results indicated that EIF3B is a novel oncogene in HNSCC that promotes CEBPB translation and IL6R expression, and these findings provide a link between the molecular basis and pathogenesis of HNSCC.

Graphical Abstract

EIF3B is a prognostic biomarker for HNSCC risk;

EIF3B promotes HNSCC progression in vitro and in vivo;

EIF3B promotes CEBPB translation and activates the MAPK pathway;

IL6R and CCNG2 are targets of EIF3B-regulated CEBPB translation.

Prediction of biomarkers and therapeutic combinations for anti-PD-1 immunotherapy using the global gene network association

Owing to a lack of response to the anti-PD1 therapy for most cancer patients, we develop a network approach to infer genes, pathways, and potential therapeutic combinations that are associated with tumor response to anti-PD1. Here, our prediction identifies genes and pathways known to be associated with anti-PD1, and is further validated by 6 CRISPR gene sets associated with tumor resistance to cytotoxic T cells and targets of the 36 compounds that have been tested in clinical trials for combination treatments with anti-PD1. Integration of our top prediction and TCGA data identifies hundreds of genes whose expression and genetic alterations that could affect response to anti-PD1 in each TCGA cancer type, and the comparison of these genes across cancer types reveals that the tumor immunoregulation associated with response to anti-PD1 would be tissue-specific. In addition, the integration identifies the gene signature to calculate the MHC I association immunoscore (MIAS) that shows a good correlation with patient response to anti-PD1 for 411 melanoma samples complied from 6 cohorts. Furthermore, mapping drug target data to the top genes in our association prediction identifies inhibitors that could potentially enhance tumor response to anti-PD1, such as inhibitors of the encoded proteins of CDK4, GSK3B, and PTK2.

EIF3B Associates with Exacerbated Clinical Features, Poor Treatment Response and Survival in Adult Philadelphia Chromosome Negative Acute Lymphoblastic Leukemia Patients

Objective: This study was undertaken to investigate eukaryotic translation initiation factor 3 subunit B (EIF3B) expression and its clinical value for indicating disease progression and prognosis in adult Philadelphia chromosome negative acute lymphoblastic leukemia (Ph^- ALL) patients. Methods: Totally, 76 adult Ph^- ALL patients and 30 healthy donors (HDs) were included. Bone marrow (BM) samples before therapy (baseline), after 4-week therapy of Ph^- ALL patients and the BM samples of HDs were collected. Then, EIF3B expression in BM was detected by reverse transcription quantitative polymerase chain reaction. Results: EIF3B expression was increased in Ph^- ALL patients compared with HDs, which distinguished Ph^- ALL patients from HDs (area under the curve [AUC]: 0.928; 95% confidence interval [CI]: 0.882-0.974) by receiver operating characteristic curve. Furthermore, higher baseline EIF3B expression was associated with elevated white blood cell and bone marrow blasts, while it was associated with lower complete remission (CR) within 4 weeks and less allogeneic hematopoietic stem cell transplant achievements in Ph^- ALL patients. Additionally, higher baseline EIF3B expression was associated with decreased disease-free survival but not overall survival. However, it was associated with raised 1-year mortality and 3-year mortality in Ph^- ALL patients. After 4-week therapy, EIF3B expression was reduced in total Ph^- ALL patients. Notably, the reduction of EIF3B expression was more obvious in Ph^- ALL patients who achieved CR within 4 weeks compared with Ph^- ALL patients who did not achieve CR within 4 weeks. Conclusion: EIF3B overexpression is related to worsened clinical features, poor treatment response and survival in adult Ph^- ALL patients.

Systematic Target Screening Revealed That Tif302 Could Be an Off-Target of the Antifungal Terbinafine in Fission Yeast

We used a heterozygous gene deletion library of fission yeasts comprising all essential and non-essential genes for a microarray screening of target genes of the antifungal terbinafine, which inhibits ergosterol synthesis via the Erg1 enzyme. We identified 14 heterozygous strains corresponding to 10 non-essential [7 ribosomal-protein (RP) coding genes, spt7, spt20, and elp2] and 4 essential genes (tif302, rpl2501, rpl31, and erg1). Expectedly, their erg1 mRNA and protein levels had decreased compared to the control strain SP286. When we studied the action mechanism of the non-essential target genes using cognate haploid deletion strains, knockout of SAGA-subunit genes caused a down-regulation in erg1 transcription compared to the control strain ED668. However, knockout of RP genes conferred no susceptibility to ergosterol-targeting antifungals. Surprisingly, the RP genes participated in the erg1 transcription as components of repressor complexes as observed in a comparison analysis of the experimental ratio of erg1 mRNA. To understand the action mechanism of the interaction between the drug and the novel essential target genes, we performed isobologram assays with terbinafine and econazole (or cycloheximide). Terbinafine susceptibility of the tif302 heterozygous strain was attributed to both decreased erg1 mRNA levels and inhibition of translation. Moreover, Tif302 was required for efficacy of both terbinafine and cycloheximide. Based on a molecular modeling analysis, terbinafine could directly bind to Tif302 in yeasts, suggesting Tif302 as a potential off-target of terbinafine. In conclusion, this genome-wide screening system can be harnessed for the identification and characterization of target genes under any condition of interest.

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.

eIF3i regulation of protein synthesis, cell proliferation, cell cycle progression, and tumorigenesis

eIF3i, a 36-kDa protein, is a putative subunit of the eIF3 complex important for translation initiation of mRNAs. It is a WD40 domain-containing protein with seven WD40 repeats that forms a β-propeller structure with an important function in pre-initiation complex formation and mRNA translation initiation. In addition to participating in the eIF3 complex formation for global translational control, eIF3i may bind to specific mRNAs and regulate their translation individually. Furthermore, eIF3i has been shown to bind to TGF-β type II receptor and participate in TGF-β signaling. It may also participate in and regulate other signaling pathways including Wnt/β-catenin pathway via translational regulation of COX-2 synthesis. These multiple canonical and noncanonical functions of eIF3i in translational control and in regulating signal transduction pathways may be responsible for its role in cell differentiation, cell cycle regulation, proliferation, and tumorigenesis. In this review, we will critically evaluate recent progresses and assess future prospects in studying eIF3i.

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.

Eukaryotic translation initiation factor 3B is overexpressed and correlates with deteriorated tumor features and unfavorable survival profiles in cervical cancer patients

OBJECTIVE

This study aimed to detect the expression of eukaryotic translation initiation factor 3B (EIF3B) and investigate its correlation with tumor features and survival in cervical cancer patients.

METHODS

This study retrospectively reviewed 187 cervical cancer (squamous cell carcinoma) patients underwent tumor resection. Immunohistochemistry was performed to determine the expression of EIF3B in tissue samples. Besides, disease free survival (DFS) and overall survival (OS) were calculated. The median follow-up duration was 69 months, and the last follow-up date was 2017/12/31.

RESULTS

EIF3B expression was higher in tumor tissue compared to paired adjacent tissue (45.5% vs. 32.1%, P= 0.015). Besides, EIF3B high expression was associated with higher Federation of Gynecology and Obstetrics (FIGO) Stage (P= 0.001) and presence of lymph node metastasis (P= 0.002). As to survival profiles, Kaplan-Meier curves disclosed that DFS (P< 0.001) and OS (P< 0.001) were both shorter in EIF3B high expression group compared to EIF3B low expression group. Multivariate Cox's regression analysis disclosed that EIF3B high expression, pathological grade III (vs I/II) and FIGO Stage III/IV (vs I/II) were independent predictive factors for unfavorable DFS as well as OS in cervical cancer patients (all P value < 0.05).

CONCLUSION

EIF3B is overexpressed, and its high expression correlates with higher FIGO Stage, lymph node metastasis and unfavorable survival profiles in cervical cancer patients.

Knockdown of eukaryotic translation initiation factor 3 subunit B inhibits cell proliferation and migration and promotes apoptosis by downregulating WNT signaling pathway in acute myeloid leukemia

The study aimed to investigate the effect of eukaryotic translation initiation factor 3 subunit B (EIF3B) on cell proliferation, migration, and apoptosis as well as the underlying mechanism in acute myeloid leukemia (AML). EIF3B expression was detected in AML-193, HL-60, OCI-AML2, and KG-1 cell lines and human primary bone marrow mononuclear cells (BMMC). EIF3B knockdown was realized by transfecting EIF3B ShRNA plasmids, and EIF3B knockdown and WNT2 overexpression were established by transfecting EIF3B ShRNA plasmids and WNT2 overexpression plasmids into KG-1 cells. The effect of EIF3B knockdown, and EIF3B knockdown plus WNT2 overexpression on cell proliferation, apoptosis, migration, glycogen synthase kinase 3B (GSK3B) and catenin beta 1 (CTNNB1) was assessed. EIF3B mRNA and protein expression were higher in AML-193, OCL-AML2 and KG-1 cell lines, but unchanged in the HL-60 cell line compared with human primary BMMC. The expression of WNT2 was decreased by EIF3B downregulation, while it had no effect on EIF3B expression. As for cell activities, EIF3B knockdown inhibited the cell proliferation and migration but promoted apoptosis by inhibiting WNT2 expression. In addition, EIF3B knockdown downregulated the expression of CTNNB1 but upregulated the expression of GSK3B by blocking WNT2 expression in AML, implying an inhibitory effect of EIF3B downregulation on WNT signaling pathway. EIF3B is upregulated and its knockdown inhibits cell proliferation, and migration, while promoting apoptosis by downregulating the WNT signaling pathway in AML.

Upregulated expression of eIF3C is associated with malignant behavior in renal cell carcinoma

Eukaryotic initiation factor 3c (eIF3C) is involved in the initiation of protein translation. Aberrant eIF3C expression has been reported in different types of human cancer. The present study aimed to assess the role of eIF3C in the malignant behavior of renal cell carcinoma in vitro and in vivo. eIF3C expression was assessed in 16 pairs of renal cell carcinoma (RCC) and matched distant normal tissues, and in RCC cell lines using immunohistochemistry. Subsequently, eIF3C was depleted using lentiviral short hairpin RNA and cell proliferation, cell cycle distribution and apoptosis of these eIF3C‑depleted cells were examined. Additionally, tumor cell xenograft assays in nude mice, Affymetrix microarrays and ingenuity pathway analyses were performed. eIF3C expression was upregulated in RCC tissues and cell lines. Depletion of eIF3C reduced tumor cell proliferation and arrested them at the G1 stage, thus promoting their apoptosis in vitro. Depletion of eIF3C also inhibited the formation and growth of tumor cell xenografts in nude mice. In addition, depletion of eIF3C altered the expression levels of 994 differentially expressed genes in RCC cells (516 genes were upregulated and 478 genes were downregulated). The expression levels of phosphorylated‑AKT, c‑JUN and NFKB inhibitor α were lower in the shorth hairpin RNA eIF3C‑transfected RCC cells compared with in the control group. In conclusion, the present study demonstrated that upregulated eIF3C expression contributed to the development and progression of RCC. Future studies should further evaluate whether eIF3C could be used as a potential strategy for RCC targeting therapy.

Eukaryotic translation initiation factor 3B downregulation inhibits cell proliferation and promotes cell apoptosis through negatively regulating tumor necrosis factor receptor superfamily member 21 in gastric cancer

BACKGROUND

This study aimed to detect eukaryotic translation initiation factor 3B (EIF3B) expression in gastric cancer (GC) cell lines, and further explore the effect of EIF3B downregulation on GC cell proliferation and apoptosis.

METHODS

EIF3B mRNA expression and protein expression in human GC cell lines (NCI-N87, AGS, HGC-27, BGC-823 and MGC80-3) and human gastric mucosal epithelial cell line (GES-1) were detected. Control siRNA (Si-NC group) and EIF3B siRNA (Si-EIF3B group) were transfected into NCI-N87 cells. Rescue experiment was performed by transfection of EIF3B siRNA (Si-EIF3B group) and EIF3B siRNA plus tumor necrosis factor receptor superfamily member 21 (TNFRSF21) siRNA (Si-EIF3B & Si-TNFRSF21 group) into NCI-N87 cells. Besides, cell proliferation, apoptosis, TNFRSF21 expression and TRAF1 expression were assessed.

RESULTS

EIF3B mRNA expression and protein expression were elevated in NCI-N87, AGS, HGC-27 and BGC-823 cell lines compared to GES-1 cell line. In NCI-N87 cells, proliferation was reduced in Si-EIF3B group compared to Si-NC group. For cell apoptosis, its rate and apoptotic marker C-Caspase 3 expression were increased but anti-apoptosis marker Bcl-2 expression was reduced in Si-EIF3B group compared to Si-NC group. Moreover, mRNA expression and protein expression of TNFRSF21 were increased in Si-EIF3B group compared to Si-NC group, while mRNA expression and protein expression of TRAF1 were reduced in Si-EIF3B group compared to Si-NC group. In rescue experiment, cell proliferation was increased but apoptosis was decreased in Si-EIF3B & Si-TNFRSF21 group compared to Si-EIF3B group.

CONCLUSIONS

EIF3B is overexpressed in GC cell lines, and its downregulation inhibits cell proliferation while promotes apoptosis through negatively regulating TNFRSF21 in GC.

TEX9 and eIF3b functionally synergize to promote the progression of esophageal squamous cell carcinoma

Background

Esophageal squamous cell carcinoma (ESCC) is one of the most frequent malignant digestive tumors around the world. We previously demonstrated that eIF3b could promote the progression of ESCC. The exact mechanisms underlying these effects remained unknown.

Methods

Quantitative proteomics was applied to detect the potential targets of Eukaryotic translation initiation factor 3 subunit b (eIF3b). RT-qPCR and Western blot were performed to detect the expression of targeted gene and pathway related genes. RNA-immunoprecipitation was applied to verify the binding of eIF3b with targeted gene. Moreover, CCK-8 assay, colony-formation assay, transwell assay, flow cytometry for cell apoptosis and tumor xenograft assay were performed to analyze the regulation of the targeted gene on the bio-function of ESCC cells.

Results

Quantitative proteomics data showed that Testis-expressed protein 9 (TEX9) expression was positively associated with eIF3b expression. RT-qPCR and Western blot results confirmed the quantitative proteomics data and demonstrated that TEX9 expression was positively correlated with TNM stage in ESCC. Furtherly, RNA-immunoprecipitation confirmed that eIF3b binding to TEX9 mRNA. The bio-function related assay demonstrated that TEX9 and eIF3b functionally synergized to promote the proliferation and migration, and inhibited the apoptosis of ESCC cells. In the analysis of mechanism, we revealed that TEX9 and eIF3b promoted the progression of ESCC through the activation of AKT signaling pathway.

Conclusions

The synergized promoting role of TEX9 and eIF3b in the progression of ESCC may provide a novel mechanism for exploring viable therapeutic strategies for ESCC.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-6071-9) contains supplementary material, which is available to authorized users.

Eukaryotic initiation factor 3B downregulation suppresses cell proliferation, migration and invasion while it induces cell apoptosis by blocking the β-catenin pathway in endometrial cancer

This study aimed to evaluate the effect of eukaryotic initiation factor 3B (EIF3B) downregulation on cell proliferation, apoptosis, migration, invasion and the β-catenin pathway in endometrial cancer. EIF3B mRNA and protein expressions were determined in human endometrial cancer cell lines (Ishikawa, HEC-1A, RL95-2 and EFE-184) and in the normal human endometrial epithelial cell line (HEEC). EIF3B siRNA and a control siRNA were transfected into HEC-1A cells, then cell proliferation, apoptosis, apoptotic marker (C-caspase 3 and Bcl-2) expressions, cell migration, and invasion were determined. β-catenin and cyclin E1 (CCNE1) expressions were also measured. EIF3B mRNA and protein expressions were increased in the Ishikawa, HEC-1A and RL95-2 cell lines, but they were similar in the EFE-184 cell line compared to the HEEC cell line. In HEC-1A cells, EIF3B siRNA suppressed cell proliferation, but it elevated the cell apoptosis rate compared to the control siRNA, and EIF3B siRNA also enhanced C-caspase 3 expression, but it inhibited Bcl-2 expression. Also, EIF3B siRNA reduced cell migration and cell invasion compared to the control siRNA in HEC-1A cells. More interestingly, EIF3B siRNA reduced β-catenin and CCNE1 mRNA as well as protein expressions compared with the control siRNA in HEC-1A cells. In conclusion, EIF3B downregulation suppresses cell proliferation, migration, and invasion, but it induces cell apoptosis by blocking the β-catenin pathway in endometrial cancer.

EIF3B is associated with poor outcomes in gastric cancer patients and promotes cancer progression via the PI3K/AKT/mTOR signaling pathway

Purpose

Eukaryotic translation initiation factor (EIF) plays a vital role in protein synthesis. EIF3B is a core subunit of the EIF3 family, and is overexpressed in many tumors. EIF3B is associated with an unfavorable prognosis, as well as the genesis and development of tumors. However, the potential role of EIF3B in gastric cancer (GC) remains unknown. In the current study, we explored the clinical significance and the possible mechanism of EIF3B in the progression of GC.

Methods

EIF3B expression was analyzed in 78 GC tissue samples through quantitative PCR and in 94 GC tissue samples through immunohistochemistry (IHC) staining. The correlation between EIF3B and clinicopathological features was analyzed in GC tissues. The role of EIF3B in GC progression was investigated through in vitro and in vivo assays.

Results

EIF3B expression was upregulated in GC tissues (73.4%, IHC). High expression of EIF3B was significantly correlated with the depth of tumor invasion, lymph node metastasis and TNM stage (P=0.000, 0.000 and 0.000, respectively). Multivariate analysis indicated that GC patients with high EIF3B expression suffered a poorer 5-year survival. EIF3B promoted GC cell proliferation and was strongly associated with proliferating cell nuclear antigen (PCNA) expression in GC samples (P=0.009). It also enhanced tumor cell migration and invasion, which were affected through epithelial-mesenchymal transition (EMT) and the Stat3 signaling pathway. Knockdown of EIF3B in GC cells suppressed the growth of xenograft tumors and lung metastatic colonization in vivo. Furthermore, gene set enrichment analysis (GSEA) and Western blot results demonstrated that EIF3B activated the PI3K/AKT/mTOR signaling pathway.

Conclusion

Our results suggest that EIF3B plays an oncogenic role in GC progression and serves as an independent prognostic factor for GC patients.

Downregulation of eukaryotic translation initiation factor 3b inhibited proliferation and metastasis of gastric cancer

Eukaryotic translation initiation factor 3 (eIF3) plays an important role in the regulation of mRNA translation, cell growth and cancer development. eIF3b is the main scaffolding subunit in the eIF3 complex and has been demonstrated to contribute to the development of several cancers. First, our study found that the downregulation of eIF3b could inhibit the proliferation and metastasis of gastric cancer cells by regulating the expression of cancer-related genes. In addition, the expression of eIF3b correlated with the stage and progression of gastric cancer and was shown to be upregulated in human chronic gastritis and in gastric cancer tissues compared with the expression of eIF3b in normal gastric tissues. Moreover, Helicobacter pylori (H. pylori) infection could upregulate the expression of eIF3b in gastric cancer cells, suggesting that eIF3b might be involved in the carcinogenic process of H. pylori. The above findings identified the oncogenic role of eIF3b in gastric cancer development, and this may contribute to the exploration and discovery of novel therapeutic targets for gastric cancer treatment.

Short Review: Genomic Alterations in Hürthle Cell Carcinoma

Hürthle cell tumors (HCT), including Hürthle cell adenomas (HCA) and Hürthle cell carcinomas (HCCs), arise in the thyroid gland and are defined in part by an accumulation of mitochondria. These neoplasms were long considered a subtype of follicular neoplasm, although HCT is now generally considered a distinct entity. HCTs exhibit overlapping but distinct clinical features compared to follicular tumors, and several studies have demonstrated that HCTs harbor distinct genomic alterations compared to other forms of thyroid cancer. Two studies recently reported the most complete characterization of the HCC genome to date. These studies assessed complementary cohorts of HCC specimens. The study by Ganly et al. consisted of a large panel of primary HCCs, including 32 widely invasive and 24 minimally invasive primary tumors. Exome and RNA sequencing of material isolated from fresh-frozen tumor specimens was performed. The study by Gopal et al. utilized exome and targeted sequencing to characterize the nuclear and mitochondrial genomes of 32 primary tumors and 38 resected regional and distant metastases using DNA isolated from formalin-fixed paraffin-embedded tissues. Here, HCC is briefly reviewed in the context of these studies.

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

In order to investigate the role of EIF3B (eukaryotic translation initiation factor 3B, EIF3B) gene in the proliferation and apoptosis of ovarian cancer cells, a lentiviral vector system and shEIF3B lentiviral vector were constructed to transfect human ovarian cancer cells. SKOV3 and HO-8910 cells were used in this experiment. The cell growth was detected by Celigo cell counting assay, the apoptosis rate was measured by flow cytometry and the cell proliferation ability of lentivirus transfected cells was tested by MTT assay and clone formation assay. Results showed that the specific shRNA had a significant inhibitory effect on the expression of EIF3B gene. Compared with the negative control, the expression of EIF3B mRNA and protein in SKOV3 and HO-8910 cells were significantly inhibited in the knockdown group. Then the proliferation rate of each group was tested, we found that SKOV3 and HO-8910 cells in siRNA lentivirus infected group was significantly decreased. Same result was obtained from the clonogenic assay of which the colony formation of transfected cells was significantly inhibited compared with the control group. Further study showed that the proliferation inhibitory effect was associated with as increased apoptosis rate of SKOV3 and HO-8910 cells in EIF3B knockdown groups. All in all, inhibition of EIF3B gene expression significantly inhibit the proliferation of ovarian cancer cells and increase the apoptosis of ovarian cancer cells. These results provide a new basis for the study of the molecular mechanism of ovarian cancer development and provide new target gene for ovarian cancer treatment.

The Biological Roles of Translation Initiation Factor 3b

Translation has important roles in almost all physiological and pathological processes, and translation initiation factors are particularly relevant to the translation initiation step, which is the most important step in translation regulation. Translation initiation factor 3b (eIF3b), a key subunit of the largest translation initiation factor 3 (eIF3), is widely considered a scaffold protein that acts to ensure the accuracy of translation initiation. A series of recent finds has revealed that eIF3 is closely related to oncogenesis. However, the concrete mechanism by which eIF3b is involve in carcinogenesis remains elusive. Here, we summarize a series of research findings regarding the relationship between eIF3b, translation and cancer.

Integrated Genomic Analysis of Hürthle Cell Cancer Reveals Oncogenic Drivers, Recurrent Mitochondrial Mutations, and Unique Chromosomal Landscapes

The molecular foundations of Hürthle cell carcinoma (HCC) are poorly understood. Here we describe a comprehensive genomic characterization of 56 primary HCC tumors that span the spectrum of tumor behavior. We elucidate the mutational profile and driver mutations and show that these tumors exhibit a wide range of recurrent mutations. Notably, we report a high number of disruptive mutations to both protein-coding and tRNA-encoding regions of the mitochondrial genome. We reveal unique chromosomal landscapes that involve whole-chromosomal duplications of chromosomes 5 and 7 and widespread loss of heterozygosity arising from haploidization and copy-number-neutral uniparental disomy. We also identify fusion genes and disrupted signaling pathways that may drive disease pathogenesis.

Up-regulation Of EIF3e Is Associated with The Progression of Esophageal Squamous Cell Carcinoma and Poor Prognosis in Patients

Introduction: Esophageal cancer is one of the most common malignant tumors in the world. Eukaryotic translation initiation factors 3e (eIF3e) makes a notable difference in the initiation of protein synthesis and tumor progression. However, the role of eIF3e in ESCC has not been revealed yet. This study aims to investigate the bio-functional and prognostic role of eIF3e in human ESCC tissues and cells. Methods: Immunohistochemical staining and Western blot were performed to detect the eIF3e expression in ESCC patients' tissues. The Kaplan-Meier product limit method and Cox regression were conducted to analyze the association between eIF3e expression, together with other related clinical/pathological features, and patients' prognosis. In the analysis of bio-functional role of eIF3e, CCK-8 and Transwell assay were performed to compare the proliferative and migrative ability after knockdown of eIF3e. Results: Up-regulation of eIF3e were demonstrated in ESCC tissues compared with the corresponding para-cancerous tissues. Overexpression of eIF3e was associated with deep tumor depth, lymph nodes metastasis, and advanced TNM stage. Importantly, the patients with high eIF3e expression suffered shorter overall and disease-free survival. Lymph node metastasis and histological grade served as independent prognostic predictors in patients' prognosis. Knockdown of eIF3e could inhibit cell proliferation and migration, in vitro. Conclusions: The eIF3e expression, or combined with other members of eIF3 complex, might predict poor prognosis of ESCC and serve as a potential breakthrough in the multimodality therapy of ESCC.

eIF3: a factor for human health and disease

The eukaryotic initiation factor 3 (eIF3) is one of the most complex translation initiation factors in mammalian cells, consisting of several subunits (eIF3a to eIF3m). It is crucial in translation initiation and termination, and in ribosomal recycling. Accordingly, deregulated eIF3 expression is associated with different pathological conditions, including cancer. In this manuscript, we discuss the interactome and function of each subunit of the human eIF3 complex. Furthermore, we review how altered levels of eIF3 subunits correlate with neurodegenerative disorders and cancer onset and development; in addition, we evaluate how such misregulation may also trigger infection cascades. A deep understanding of the molecular mechanisms underlying eIF3 role in human disease is essential to develop new eIF3-targeted therapeutic approaches and thus, overcome such conditions.

Eukaryotic Translation Initiation Factor 3b is both a Promising Prognostic Biomarker and a Potential Therapeutic Target for Patients with Clear Cell Renal Cell Carcinoma

Eukaryotic translation initiation factors (eIFs) constitute a new class of therapeutic cancer targets. EIF3b is the major scaffold protein of eIF3 (the largest core of eIFs). We sought to define the role played by and the mechanism of action of eIF3b in patients with clear cell renal cell carcinoma (ccRCC). We found that high-level eIF3b expression in tumors was not only associated with an aggressive tumor phenotype, but was also independently prognostic for patients with ccRCC. Knockdown of eIF3b impaired the action of the Akt pathway, thus inhibiting cell proliferation by disrupting the cell cycle and triggering apoptosis. Furthermore, the epithelial-to-mesenchymal transition was impaired after eIF3b depletion, via suppression of cell migration and invasion. Additionally, eIF3b knockdown significantly inhibited the growth of subcutaneous xenografts in mice. Together, these data show that eIF3b is both a promising prognostic biomarker and a potential therapeutic target for patients with ccRCC.

Eukaryotic translation initiation factors and cancer

Recent technological advancements have shown tremendous mechanistic accomplishments in our understanding of the mechanism of messenger RNA translation in eukaryotic cells. Eukaryotic messenger RNA translation is very complex process that includes four phases (initiation, elongation, termination, and ribosome recycling) and diverse mechanisms involving protein and non-protein molecules. Translation regulation is principally achieved during initiation step of translation, which is organized by multiple eukaryotic translation initiation factors. Eukaryotic translation initiation factor proteins help in stabilizing the formation of the functional ribosome around the start codon and provide regulatory mechanisms in translation initiation. Dysregulated messenger RNA translation is a common feature of tumorigenesis. Various oncogenic and tumor suppressive genes affect/are affected by the translation machinery, making the components of the translation apparatus promising therapeutic targets for the novel anticancer drug. This review provides details on the role of eukaryotic translation initiation factors in messenger RNA translation initiation, their contribution to onset and progression of tumor, and how dysregulated eukaryotic translation initiation factors can be used as a target to treat carcinogenesis.