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.

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.

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.

雷帕霉素对柯萨奇病毒B3诱导的大鼠心肌细胞mTOR和eIF-4E表达的调控作用

目的:研究雷帕霉素对柯萨奇病毒B3(coxsackievirus B3,CVB3)诱导的心肌细胞哺乳类雷帕霉素靶蛋白(mammalian target of rapamycin,mTOR)和真核起始因子4E(eukaryotic initiation factor-4E,eIF-4E)表达的调控,探讨mTOR/eIF-4E信号传导在病毒性心肌炎(viral myocarditis,VM)的作用。方法:CVB3感染原代培养的SD大鼠心肌细胞建立病毒性心肌炎的细胞模型。根据细胞毒力实验筛选10 nmol/L的雷帕霉素干预CVB3感染的心肌细胞,采用RT-PCR和Western免疫印迹方法检测mTOR和eIF-4E mRNA表达及蛋白质水平。结果:CVB3诱导心肌细胞变性,雷帕霉素可减轻其变性;CVB3使大鼠心肌细胞的mTOR和eIF-4E mRNA和蛋白表达上调,与对照组比较,有统计学差异(P<0.05),雷帕霉素可使CVB3感染的心肌细胞mTOR和eIF-4E mRNA和蛋白表达明显下调,与CVB3组比较,有统计学差异(P<0.05)。结论:雷帕霉素能明显抑制CVB3感染的大鼠心肌细胞mTOR和eIF-4E表达,提示mTOR/eIF-4E信号传导在病毒性心肌炎中可能起重要作用。

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.

Structure and functions of the translation initiation factor eIF4E and its role in cancer development and treatment

In eukaryotic cells, protein synthesis is a complex and multi-step process that has several mechanisms to start the translation including cap-dependent and cap-independent initiation. The translation control of eukaryotic gene expression occurs principally at the initiation step. In this context, it is critical that the eukaryotic translation initiation factor eIF4E bind to the 7-methylguanosine （m7G） cap present at the 5＇- UTRs of most eukaryotic mRNAs. Combined with other initiation factors, elF4E mediates the mRNA recruitment on ribosomes to start the translation. Moreover, the eIF4E nuclear bodies are involved in the export of specific mRNAs from the nucleus to the cytoplasm. In this review, we focus on the elF4E structure and its physiological functions, and describe the role of eIF4E in cancer development and progression and the current therapeutic strategies to target eIF4E.

Regulation of Eukaryotic Initiation Factor 4E and Its Isoform： Implications for Antiviral Strategy in Plants

In recent years, biotechnology has permitted regulation of the expression of endogenous plant genes to improve agronomlcally important traits. Genetic modification of crops has benefited from emerging knowledge of new genes, especially genes that exhibit novel functions, one of which is eukaryotlc initiation factor 4E （eIF4E）. eIF4E Is one of the most important translation initiation factors Involved in eukaryotic initiation. Recent research has demonstrated that virus resistance mediated by eIF4E and Its isoform elf （Iso）4E occurs in several plant-virus interactions, thus indicating a potential new role for eIF4E/elF（Iso）4E In resistance strategies against plant viruses. In this review, we briefly describe eIF4E activity In plant translation, its potential role, and functions of the eIF4E subfamily In plant-virus interactions. Other initiation factors such as elF4G could also play a role In plant resistance against viruses. Finally, the potential for developing eIF4E-mediated resistance to plant viruses in the future Is discussed. Future research should focus on elucidation of the resistance mechanism and spectrum mediated by eIF4E. Knowledge of a particu- lar plant-virus interaction will help to deepen our understanding of eIF4E and other eukaryotic Initiation factors, and their involvement in virus disease control.

Total Saponins of Rubus Parvifolius L.Exhibited Anti-Leukemia Effect in vivo through STAT3 and eIF4E Signaling Pathways

Objective： To investigate the anti-leukemia effect of total saponins of Rubus parvifo/ius L. （TSRP） on K562 cell xenografts in nude mice and the mechanisms of action. Methods： The K562 cell xenografts in nude mice were established, and then randomly divided into 5 groups, the control group, the cytosine arabinoside group（Am-c） and 3 TSRP groups （20, 40 and 100 mg/kg）. The tumor volume and mass of each group of nude mice were measured and the anti-tumor rates of TSRP were calculated subsequently. The apoptosis status of tumor cells was detected by hematoxylin-eosin （HE） and terminal dexynucleotidyl transferase （TdT）-mediated dUTP nick end labeling （TUNEL） staining analysis. Finally, the activities of apoptosis related signaling of signal transducer and activator of transcription 3 （STAT3）, eukaryotic initiation factor 4E （eIF4E） and B-cell lymphoma-2 （bcl-2） were determined with immunohistochemistry tests. Results： Subcutaneous injection of K562 cells induced tumor formation in nude mice, and the TSRP treated group showed a significant inhibitory effect on tumor formation. The nude mice treated with TSRP showed a significant decrease in tumor growth rate and tumor weight in comparison to the control group （all P〈0.05）. The HE staining and TUNEL assay showed that TSRP induced cell death by apoptosis. The immunohistochemical assay showed down-regulation of the bcl-2 gene in the TSRP treated cells. The phosphorylation levels of elF4E and STAT3 were decreased obviously after the treatment of TSRP. Conclusion： TSRP had an excellent tumor-suppressing effect on K562 cells in the nude mice xenograft model, suggesting that TSPR can be developed as a promising anti-chronic myeloide leukemia drug.

磷酸化哺乳动物雷帕霉素靶蛋白和磷酸化真核细胞翻译启示因子4E结合蛋白1在病理性瘢痕中的表达

目的 探讨磷酸化哺乳动物雷帕霉素靶蛋白（p-mTOR）和磷酸化真核细胞翻译启始因子4E结合蛋白l（p-4EBP1）在病理性瘢痕、非病理性瘢痕及正常皮肤组织中的表达水平,了解其在病理性瘢痕形成中的意义.方法 采用免疫组织化学SP法检测p-mTOR、p-4EBP1在20例瘢痕疙瘩、20例增生性瘢痕、20例非病理性瘢痕及20例正常皮肤组织中的表达水平,分析其在不同组织中表达阳性率及病理性瘢痕中两者相关关系.结果 瘢痕疙瘩和增生性瘢痕中p-mTOR、p-4EBP1蛋白阳性表达率分别为75.0％（15/20）和60.0％（12/20）、60.0％（12/20）和50.0％（10/20）,高于非病理性瘢痕20％（4/20）和10％ （2/20）及正常皮肤10％ （2/20）和5％ （1/20） （P＜0.05）;p-mTOR与p-4EBP1表达相关（r=0.338,P＜0.05）.结论 p-mTOR和p-4EBP1可能共同参与了病理性瘢痕的形成过程,且两者具有协同作用.

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.