Detection of eukaryotic translation initiation factor 4E and its clinical significance in hepatocellular carcinoma

AIM:To study the expression of eukaryotic translation initiation factor 4E(eIF4E),which is closely correlated with malignant tumors,and its relationship to prognosis in hepatocellular carcinoma. METHODS:Western blotting was performed to quantify the elF4E protein expression in the normal human liver cell line L02 and the hepatoma cell lines Hep3B, HepG2,and Huh7.Forty-six hepatocellular carcinoma samples with complete clinical data were obtained from Changzheng Hospital during the period of December 2008 to July 2009.The expression of eIF4E in the tumor samples and their adjacent tissues were detected by immunohistochemistry.The relationship between the test results and hepatocellular carcinoma(HCC) prognosis was statistically analysed by using a COX proportional hazard model. RESULTS:Western blotting analysis showed that there were distinct eIF4E protein bands in all three of the hepatoma cell lines.In particular,the HepG2 cell line had the highest level of eIF4E protein expression.The L02 cell group had a low eIF4E expression.Immunohistochemical assay showed that there were 32 cases in which the tumour tissue expression was higher than their adjacent tissues,accounting for 69.57%.There were also 14 cases in which the tumour tissue expression was lower or no significant difference was found, accounting for 30.43%.COX proportional hazards model analysis showed that HCC prognosis was related to the depth of invasion,the overexpression of eIF4E and p53, possibly as independent HCC prognostic predictors. CONCLUSION:In summary,eIF4E expression is associated with liver cancer,and patients with high eIF4E expression levels have a higher risk of recurrence.

Relationship between Eukaryotic Translation Initiation Factor 4E and Malignant Angiogenesis in Non-Hodgkin Lymphoma

The relationship between angiogenesis and eukaryotic translation initiation factor 4E （EIF4E） expression level in non Hodgkin lymphoma （NHL） was studied. Mean microvessel density （MVD） and EIF4E were detected in 52 lymph node samples paraffin sections of patients with newly diagnosed NHL by the way of immunohistochemistry. Antisense EIF4E cDNA was cloned into plasmid pcDNA3.1 （＋） and transfected into Raji cells. A series of angiogenesis related factors,including vascular endothelial growth factor （VEGF）, matrix metalloproteinases 9 （MMP-9） and tissue inhibitor of metalloproteinases-2 （TIMP-2） proteins were detected by Western blot. The results showed that： （1） The Expression of EIF4E and MVD was higher in aggressive lymphomas than in indolent lymphomas（P〈0.05）and the expression of EIF4E was positively correlated with MVD in lymph node of NHL（r=0. 695, P〈0.01）. （2） Antisense EIF4E eukaryocytic expression vector （pcDNA3. 1-EIF4Eas） was constructed successfully. （3） EIF4E, VEGF and MMP-9 were expressed at high levels in Raji cells as compared to normal human peripheral blood monocular cells （NHPMC）, and blockage of EIF4E expression brought down the expression of VEGF and MMP-9. However, TIMP-2 was undetectable in Rail cells, although a moderate level of TIMP-2 was detected in NHPMC. It was concluded that the increased EIF4E expression was associated with aggressive property of NHL.

Cloning and Characterization of Eukaryotic Translation Initiation Factor 4E (eIF4E) Gene Family in Ipomoea batatas L. (Lam) for Understanding Hexaploid Sweetpotato-Virus Interactions

Characterization of genes related to sweetpotato viral disease resistance is critical for understanding plant-pathogen interactions, especially with feathery mottle virus infection. For example, genes encoding eukaryotic translation initiation factor (eIF)4E, its isoforms, eIF(iso)4E, and the cap-binding protein (CBP) in plants, have been implicated in viral infections aside from their importance in protein synthesis. Full-length cDNA encoding these putative eIF targets from susceptible/resistant and unknown hexaploid sweetpotato (Ipomoea batatas L. Lam) were amplified based on primers designed from the diploid wild-type relative Ipomoea trifida consensus sequences, and designated IbeIF4E, IbeIF(iso)4E and IbCBP. Comparative analyses following direct-sequencing of PCR-amplified cDNAs versus the cloned cDNA sequences identified multiple homeoalleles: one to four IbeIF4E, two to three IbeIF(iso)4E, and two IbCBP within all cultivars tested. Open reading frames were in the length of 696 bp IbeIF4E, 606 bp IbeIF(iso)4E, and 675 bp IbCBP. The encoded single polypeptide lengths were 232, 202, and 225 amino acids for IbeIF4E, IbeIF(iso)4E, and IbCBP, with a calculated protein molecular mass of 26 kDa, 22.8 kDa, and 25.8 kDa, while their theoretical isoelectric points were 5.1, 5.57, and 6.6, respectively. Although the homeoalleles had similar sequence lengths, single nucleotide polymorphisms and multi-allelic variations were detected within the coding sequences. The multi-sequence alignment performed revealed a 66.9% - 96.7% sequence similarity between the predicted amino acid sequences obtained from the homeoalleles and closely related species. Furthermore, phylogenetic analysis revealed ancestral relationships between the eIF4E homeoalleles and other species. The outcome herein on the eIF4E superfamily and its correlation in sequence variations suggest opportunities to decipher the role of eIF4E in hexaploid sweetpotato feathery mottle virus infection.

eIF-Three to Tango: emerging functions of translation initiation factor eIF3 in protein synthesis and disease

Studies over the past three years have substantially expanded the involvements of eukaryotic initiation factor 3 (eIF3) in messenger RNA (mRNA) translation. It now appears that this multi-subunit complex is involved in every possible form of mRNA translation, controlling every step of protein synthesis from initiation to elongation, termination, and quality control in positive as well as negative fashion. Through the study of eIF3, we are beginning to appreciate protein synthesis as a highly integrated process coordinating protein production with protein folding, subcellular targeting, and degradation. At the same time, eIF3 subunits appear to have specific functions that probably vary between different tissues and individual cells. Considering the broad functions of eIF3 in protein homeostasis, it comes as little surprise that eIF3 is increasingly implicated in major human diseases and first attempts at therapeutically targeting eIF3 have been undertaken. Much remains to be learned, however, about subunit- and tissue-specific functions of eIF3 in protein synthesis and disease and their regulation by environmental conditions and post-translational modifications.

Crystal structure of the C-terminal domain of the ε subunit of human translation initiation factor eIF2B

Eukaryotic translation initiation factor eIF2B,the guanine nucleotide exchange factor(GEF)for eIF2,catalyzes conversion of eIF2·GDP to eIF2·GTP.The eIF2B is composed of five subunits,α,β,γ,δandε,within which theεsubunit is responsible for catalyzing the guanine exchange reaction.Here we present the crystal structure of the C-terminal domain of human eIF2Bε(eIF2Bε-CTD)at 2.0-Åresolution.The structure resembles a HEAT motif and three charge-rich areas on its surface can be identified.When compared to yeast eIF2Bε-CTD,one area involves highly conserved AA boxes while the other two are only partially conserved.In addition,the previously reported mutations in human eIF2Bε-CTD,which are related to the loss of the GEF activity and human VWM disease,have been discussed.Based on the structure,most of such mutations tend to destabilize the HEAT motif.

The Prognostic Value of Pathological and Molecular Margins Marked by p53 and eIF4E in Laryngeal Carcinoma

Objective: To study the prognostic value of the pathological margin and molecular margin marked by eIF4E and P53 protein in laryngeal carcinoma. Methods: The prognostic value of pathological and molecular margin was studied in 253 cases and 67 cases respectively, the latter were pathological negative margin chosen from the former. Immunohistochemisty was used to detect the expression of eIF4E and p53 proteins. Results: The rate of pathological, p53 and eIF4E positive margins was 20.2%, 19.4% and 32.8% respectively. The recurrent rate of those with positive margins was higher than that of negative margins, which including pathological margin (70.6% vs 35.1%, P =0.0000), p53 margin (69.2% vs 33.3%, P =0.018) and eIF4E margin (63.6% vs 28.9%, P =0.018); The survival rate of those with negative margins was higher than those with positive margins, including pathological margin (the 5-year cumulative survival rate was 37.52% and 64.37% respectively, P =0.0023), p53 margin (the 5-year cumulative survival rate was 24.62% and 75.69% respectively, P =0.0012) and eIF4E margin (the 5-year cumulative survival rate was 43.31% and 77.52% respectively, P =0.0006). Conclusion: The prognosis of those with both pathological and molecular positive margins was worse than that of the negative margins; Both the eIF4E and p53 were useful markers to pick out the poor prognostic patients from those with pathological negative margin, and the former seemed to be more potential.

Valproate reduces retinal ganglion cell apoptosis in rats after optic nerve crush

The retinal ganglion cells of the optic nerve have a limited capacity for self-repair after injury.Valproate is a histone deacetylase inhibitor and multitarget drug,which has been demonstrated to protect retinal neurons.In this study,we established rat models of optic nerve-crush injury and injected valproate into the vitreous cavity immediately after modeling.We evaluated changes in the ultrastructure morphology of the endoplasmic reticulum of retinal ganglion cells over time via transmission electron microscope.Immunohistochemistry and western blot assay revealed that valproate upregulated the expression of the endoplasmic reticulum stress marker glucose-regulated protein 78 and downregulated the expression of transcription factor C/EBP homologous protein,phosphorylated eukaryotic translation initiation factor 2α,and caspase-12 in the endoplasmic reticulum of retinal ganglion cells.These findings suggest that valproate reduces apoptosis of retinal ganglion cells in the rat after optic nerve-crush injury by attenuating phosphorylated eukaryotic translation initiation factor 2α-C/EBP homologous protein signaling and caspase-12 activation during endoplasmic reticulum stress.These findings represent a newly discovered mechanism that regulates how valproate protects neurons.

ARID1A Inactivation Increases Expression of circ0008399 and Promotes Cisplatin Resistance in Bladder Cancer

Objective Cisplatin(CDDP)-based chemotherapy is a first-line,drug regimen for muscle-invasive bladder cancer(BC)and metastatic bladder cancer.Clinically,resistance to CDDP restricts the clinical benefit of some bladder cancer patients.AT-rich interaction domain 1A(ARID1A)gene mutation occurs frequently in bladder cancer;however,the role of CDDP sensitivity in BC has not been studied.Methods We established ARID1A knockout BC cell lines using CRISPR/Cas9 technology.IC50 determination,flow cytometry analysis of apoptosis,and tumor xenograft assays were performed to verify changes in the CDDP sensitivity of BC cells losing ARID1A.qRT-PCR,Western blotting,RNA interference,bioinformatic analysis,and ChIP-qPCR analysis were performed to further explore the potential mechanism of ARID1A inactivation in CDDP sensitivity in BC.Results It was found that ARID1A inactivation was associated with CDDP resistance in BC cells.Mechanically,loss of ARID1A promoted the expression of eukaryotic translation initiation factor 4A3(EIF4A3)through epigenetic regulation.Increased expression of EIF4A3 promoted the expression of hsa_circ_0008399(circ0008399),a novel circular RNA(circRNA)identified in our previous study,which,to some extent,showed that ARID1A deletion caused CDDP resistance through the inhibitory effect of circ0008399 on the apoptosis of BC cells.Importantly,EIF4A3-IN-2 specifically inhibited the activity of EIF4A3 to reduce circ0008399 production and restored the sensitivity of ARID1A inactivated BC cells to CDDP.Conclusion Our research deepens the understanding of the mechanisms of CDDP resistance in BC and elucidates a potential strategy to improve the efficacy of CDDP in BC patients with ARID1A deletion through combination therapy targeting EIF4A3.

Cloning and Expression Analysis of eIF5A Gene from Litopenaeus vannamei

Eukaryotic translation initiation factor 5A （eIFSA） is a protein-translation initiation factor in eukaryotic cells. Recent studies found that elFSA plays an important role in regulating the processes of cellular senescence and death, environmental stress response and immune response in animal and plant cells. In the present study, a cDNA containing the complete amino acid sequence of eIFSA was obtained for the first time by sequencing the Litopenaeus vannamei cDNA library, which contained a 474 bp long open reading frame encoding 157 amino acids, with the predicted molecular weight of about 17. 257 ku and theoretical isoelectric point of 5.06. Comparison analysis showed that the amino acid sequence of elFSA gene in L vannamei shared relatively high homology with that in other species. Real-time quantitative RT-PCR results indicated that the mRNA expression of elFSA gene in different tissues of L. vannamei exhibited no significant difference. Real-time quantitative RT-PCR analysis of L. vannamei hepatopancreas infected with WSSV, TSV and IHHNV showed that the mRNA levels of elFSA gene was re- spectively significantly increased, which was 2.2, 2.5 and 1.6 times of that in control group, indicating that eIFSA may be involved in the antiviral immune response of L. vannamei.

High expression of autophagy-related gene EIF4EBP1 could promote tamoxifen resistance and predict poor prognosis in breast cancer

BACKGROUND Breast cancer(BC) remains a public health problem. Tamoxifen(TAM) resistance has caused great difficulties for treatment of BC patients. Eukaryotic translation initiation factor 4E binding protein 1(EIF4EBP1) plays critical roles in the tumorigenesis and progression of BC. However, the expression and mechanism of EIF4EBP1 in determining the efficacy of TAM therapy in BC patients are still unclear.AIM To investigate the expression and functions of EIF4EBP1 in determining the efficacy of TAM therapy in BC patients.METHODS High-throughput sequencing data of breast tumors were downloaded from the Gene Expression Omnibus database. Differential gene expression analysis identified EIF4EBP1 to be significantly upregulated in cancer tissues. Its prognostic value was analyzed. The biological function and related pathways of EIF4EBP1 was analyzed. Subsequently, the expression of EIF4EBP1 was determined by real-time reverse transcription polymerase chain reaction and western blotting. Cell Counting Kit-8 assays, colony formation assay and wound healing assay were used to understand the phenotypes of function of EIF4EBP1.RESULTS EIF4EBP1 was upregulated in the TAM-resistant cells, and EIF4EBP1 was related to the prognosis of BC patients. Gene Set Enrichment Analysis showed that EIF4EBP1 might be involved in Hedgehog signaling pathways. Decreasing the expression of EIF4EBP1 could reverse TAM resistance, whereas overexpression of EIF4EBP1 promoted TAM resistance.CONCLUSION This study indicated that EIF4EBP1 was overexpressed in the BC and TAM-resistant cell line, which increased cell proliferation, invasion, migration and TAM resistance in BC cells.

Tumor necrosis factor a accelerates Hep-2 cells proliferation by suppressing TRPP2 expression

TRPP2, a Ca2＋-permeable non-selective cation channel, has been shown to negatively regulate cell cycle, but the mechanism underlying this regulation is unknown. Tumor necrosis factor a （TNF-a） is a proinflammatory cytokine extensively involved in immune system regulation, cell proliferation and cell survival. However, the effects and mechanisms for the role of TNF-a in laryngeal cancer remain unclear. Here, we demonstrated using western blot analyses and intracellular Ca〉 concentration measurements that TNF-a treatment suppressed both TRPP2 expression and ATP-induced Ca2＋ release in a laryngeal cancer cell line （Hep-2）. Knockdown of TRPP2 by a specific siRNA significantly decreased ATP-induced Ca2＋ release and abolished the effect of TNF-a on the ATP-induced Ca2＋ release. TNF-a treatment also enhanced Hep-2 cell proliferation and growth, as determined using cell counting and flow cytometry cell cycle assays. Moreover, TNF-a treatment down-regulated phosphorylated protein kinase R-like endoplasmic reticulum kinase （p-PERK） and phosphorylated eukaryotic translation initiation factor （p-elF2c0 expression levels, without affecting PERK and elF2ct expression levels in Hep-2 cells. We concluded that suppressing TRPP2 expression and TRPP2-mediated Ca2＋ signaling may be one mechanism underlying TNF〈t-enhanced Hep-2 cell proliferation. These results offer new insights into the mechanisms of TNF-a-mediated laryngeal cancer cell proliferation, and provide evidences showing a potential role of TNF-a in the development of laryngeal cancer.

Characterization of two constitutive promoters RPS28 and EIF1 for studying soybean growth,development,and symbiotic nodule development

Native promoters that can drive high and stable transgene expression are important tools for modifying plant traits.Although several such promoters have been reported in soybean(Glycine max),few of them function at multiple growth and development stages and during nodule development.Here,we report that the promoters of 40S RIBOSOMAL PROTEIN SMALL SUBUNIT S28(RPS28)and EUKARYOTIC TRANSLATION INITIATION FACTOR 1(EIF1)are ideal for high expression of transgene.Through bioinformatic analysis,we determined that RPS28 and EIF1 were highly expressed during soybean growth and development,nodule development,and various biotic and abiotic stresses.Fusion of both RPS28 and EIF1 promoters,with or without their first intron,with the reporter geneβ-GLUCURONIDASE(uidA)in transgenic soybean,resulted in high GUS activity in seedlings,seeds,and nodules.Fluorimetric GUS assays showed that the RPS28 promoter and the EIF1 promoter yielded high expression,comparable to the soybean Ubiquitin(GmUbi)promoter.RPS28 and EIF1 promoters were also highly expressed in Arabidopsis thaliana and Nicotiana benthamiana.Our results indicate the potential of RPS28 and EIF1 promoters to facilitate future genetic engineering and breeding to improve the quality and yield of soybean,as well as in a wide variety of other plant species.

Oral everolimus inhibits intimal proliferation in injured carotid artery in rats

Background Everolimus, a derivative of sirolimus, is a potent immunosuppressant that has important anti-proliferative properties. In the present study, we demonstrated the inhibiting neointimal hyperplasia in injured carotid arteries in rats by using two different doses of everolimus administrated via the oral route for a long time. Methods A rat model of carotid artery injury was established by balloon inflation. Eighty rats were randomly divided into the sham-operated group （n=20）, injury group （n=20）, low dosage of everolimus group （n=20）, and high dosage of everolimus group （n=20）. The low close of everolimus （1.5 mg/kg） was given one day before injuring the carotid artery by balloon, followed by 0.75 mg/kg per day for 28 days via intragastric gavage. High dose everolimus （2.5 mg/kg） was given one day before injuring the carotid artery by balloon, followed by 1 mg/kg per day for 28 days. Expression of eukaryotic translation initiation factor 4E （elF-4E） and phosphorylation of ribosomal proteinS6 kinase 1 （P70S6K） were determined by reverse transcription-polymerase chain reaction and Western blotting analysis. Results In the injured carotid artery, neointimal hyperplasia was normally observed four weeks after injury. Everolimus inhibited neointimal hyperplasia after balloon injury in a dose dependent manner. At the same time, the study demonstrated that everolimus reduced the expression of P-P70S6K, elF-4E, transforming growth factor （TGF）-131 and of proliferating cell nuclear antigen （PCNA）. Conclusions Everolimus significantly inhibited neointimal hyperplasia of the injured carotid artery. The effect depended on dosaqe and was associated with the reduction of phosphorylation of P70S6K and the elF-4E expression level.