MicroRNAs (miRNAs) recruit the RNA-induced silencing complex (RISC) to repress the translation of target mRNAs. While the 5' 7-methylguanosine cap of target mRNAs has been well known to be important for miRNA repression, the underlying mechanism is not clear. Here we show that TNRC6A interacts with eIF4E2, a homologue of eIF4E that can bind to the cap but cannot interact with eIF4G to initiate translation, to inhibit the translation of target mRNAs. Downregulation of eIF4E2 relieved miRNA repression of reporter expression. Moreover, eIF4E2 downregulation increased the protein levels of endogenous IMP1, PTEN and PDCD4, whose expression are repressed by endogenous miRNAs. We further provide evidence showing that miRNA enhances eIF4E2 association with the target mRNA. We propose that miRNAs recruit eIF4E2 to compete with eIF4E to repress mRNA translation.
Autoantigens ; metabolism ; Cell Line ; Eukaryotic Initiation Factor-4E ; metabolism ; Gene Silencing ; Humans ; MicroRNAs ; genetics ; Protein Transport ; RNA, Messenger ; biosynthesis ; genetics ; RNA-Binding Proteins ; metabolism

OBJECTIVETo determine whether the eukaryotic initiation factor-4E (eIF-4E) is involved in the cap-dependent translational regulation of heparanase and study the correlation between heparanase expression and metastatic potential of LS-174T cells.

METHODSThe protein and mRNA levels of inhibited eIF-4E were tested by Western blot and RT-PCR. Heparanase activity was defined as the ability to degrade high molecular weight (40-100 000) radiolabeled ((35)S) heparan sulfate (HS) substrate into low molecular weight (5-15 000) HS fragments. The invasive potential of tumor cells in vitro was observed by Matrigel invasion assay system.

RESULTSThe 20-mer antisense oligonucleotide (asODN) against eIF-4E specifically and significantly inhibited eIF-4E expression at both transcriptional and translational levels. The expression and the activity of heparanase were effectively lowered, which further decreased the invasive potential of LS-174T.

CONCLUSIONeIF-4E, probably being involved in translational regulation of heparanase in colon adenocarcinoma cell line LS-174T, can be a particularly interesting target for heparanase regulation, based on of its critical function.

Adenocarcinoma ; enzymology ; pathology ; Cell Line, Tumor ; Colonic Neoplasms ; enzymology ; pathology ; Eukaryotic Initiation Factor-4E ; antagonists & inhibitors ; genetics ; physiology ; Glucuronidase ; metabolism ; Humans ; Neoplasm Invasiveness

OBJECTIVETo study the expression of eIF4E, p-eIF4E (Ser 209) and Mcl-1 gene in the pathological scars and to investigate its role and its probable mechanism in the pathogenesis of abnormal scar.

METHODSQuantitative real-time PCR and Western Blot was performed to detect the expression and distribution of mRNA and protein of eIF4E and Mcl-1 in hypertrophic scar (10 cases), keloid (10 cases), normal scar (10 cases), and normal skin (10 cases). Western Blot was performed to detect the expression and distribution of protein of p-eIF4E in hypertrophic scar (10 cases), keloid (10 cases), normal scar (10 cases), and normal skin (10 cases).

RESULTSThe expression of eIF4E mRNA and protein were 1.38 +/- 0.45, 1.23 +/- 0.23 in the normal skin (10 cases); 5.400 +/- 0.450, 5.460 +/- 0.460 in normal scar (10 cases); 0.597 +/- 0.060, 0.590 +/- 0.040 in hypertrophic scar (10 cases) and 0.694 +/- 0.066, 0.697 +/- 0.022 in keloid (10 cases). The expression of p-eIF4E protein in the normal skin (10 cases), normal scar (10 cases), hypertrophic scar (10 cases), and keloid (10 cases) were 0.202 +/- 0.037, 0.216 +/- 0.019, 0.426 +/- 0.026, 0.433 +/- 0.027. The expression of Mcl-1 mRNA and protein were 1.510 +/- 0.660, 1.400 +/- 0.530 in the normal skin (10 cases); 6.65 +/- 0.85, 7.23 +/- 1.53 in normal scar (10 cases); 0.589 +/- 0.059, 0.660 +/- 0.063 in hypertrophic scar (10 cases) and 0.870 +/- 0.118, 0.914 +/- 0.064 in the keloid (10 cases). The positive rate of mRNA and protein of eIF4E and Mcl-1 was not statistically different between the hypertrophic scar and keloid (P > 0.05), while they were all remarkably significant between normal scar and abnormal scar (P < 0.05). The phosphorylation of eIF4E in pathological scar was higher than that in control group. In pathological scar, mRNA and protein of eIF4E and Mcl-1 showed a strong positive correlation.

CONCLUSIONSThe result indicates that the expression of eIF4E, p-eIF4E and Mcl-1 is increased in pathological scar. eIF4E plays an important role in pathological scar. Its activity is regulated by its phosphorylation. Therefore, eIF4E, p-eIF4E and Mcl-1 overexpression may play an important role in the proliferation of fibroblasts and in the pathogenesis of pathological scar.

Adolescent ; Adult ; Case-Control Studies ; Cicatrix ; metabolism ; Eukaryotic Initiation Factor-4E ; genetics ; metabolism ; Female ; Humans ; Keloid ; metabolism ; Male ; Myeloid Cell Leukemia Sequence 1 Protein ; genetics ; metabolism ; Phosphorylation ; RNA, Messenger ; genetics ; Young Adult

OBJECTIVE: To explore the possibility of 10-23DNAzyme becoming a new gene therapy for laryngeal carcinoma treatment at the cell level. METHOD: Thiosthorothioate 10-23DNAzyme specific to eIF4E gene mRNA 1059 was designed and synthesized, and its inhibition effects on the expression of eIF4E gene in Hep-2 cells were observed. RESULT: The expression of eIF4E gene was remarkable depressed after Hep-2 cells was transfected by DNAzyme. The level of inhibiting eIF4E in hep-2 cells transfected by DNAzyme was lower than that by only lipofectamine 2000 transfected and Hep-2. CONCLUSION The expression of eIF4E gene in Hep-2 cells 10-23DNAzyme can be highly blocked. It is a specific and effective gene therapeutic means.
Apoptosis ; Cell Line, Tumor ; DNA, Catalytic ; genetics ; DNA, Single-Stranded ; genetics ; Eukaryotic Initiation Factor-4E ; genetics ; metabolism ; Gene Expression ; Genetic Therapy ; Humans ; Laryngeal Neoplasms ; genetics ; RNA, Messenger ; genetics ; Transfection

This study was aimed to compare the expression level of eIF4E in patients with leukemia and normal controls, and to explore its role in leukemogenesis. White blood cells were collected in 76 leukemia patients and 10 healthy volunteers. The mRNA and protein expressions of eIF4E were detected by QT-PCR and Western blot in 39 cases of acute myeloid leukemia (AML), 15 cases of chronic myeloid leukemia (CML), 22 cases of acute lymphocytic leukemia (ALL) and 10 healthy volunteers as normal controls. The results demonstrated that compared with normal controls, the absolute expression levels of eIF4E mRNA increased in patients with AML, ALL and CML in blastic phase (P < 0.05), but had no significant change between groups of CML in chronic and accelerated phase although some increasing in group of CML in accelerated phase. The relative expression level of eIF4E mRNA had no significant change in AML, ALL, CML groups except the two subtypes of leukemia M4 and M5. Furthermore, the protein expression level in group of CML in accelerated phase and blastic phase and all acute leukemia patients including AML and ALL were higher than that in normal controls (P < 0.05). It is concluded that although its mRNA relative expressions had no significant change in most leukemia patients, the absolute expression level of eIF4E mRNA and its protein expression is up-regulated in most leukemia patients, which may play an important role in leukemogenesis, so the eIF4E may be a promising target for leukemia therapy and eIF4E-targeted therapy may be an option especially for the relapse and refractory leukemia.
Adolescent ; Adult ; Aged ; Case-Control Studies ; Eukaryotic Initiation Factor-4E ; genetics ; metabolism ; Female ; Humans ; Leukemia ; genetics ; metabolism ; pathology ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; Leukemia, Myeloid, Acute ; Male ; Middle Aged ; Precursor Cell Lymphoblastic Leukemia-Lymphoma ; RNA, Messenger ; genetics ; Young Adult

Activity-dependent dendritic translation in CNS neurons is important for the synapse-specific provision of proteins that may be necessary for strengthening of synaptic connections. A major rate-limiting factor during protein synthesis is the availability of eukaryotic translation initiation factor 4E (eIF4E), an mRNA 5'-cap-binding protein. In this study we show by fluorescence in situ hybridization (FISH) that the mRNA for eIF4E is present in the dendrites of cultured rat hippocampal neurons. Under basal culture conditions, 58.7 +/- 11.6% of the eIF4E mRNA clusters localize with or immediately adjacent to PSD-95 clusters. Neuronal activation with KCl (60 mM, 10 min) very significantly increases the number of eIF4E mRNA clusters in dendrites by 50.1 and 74.5% at 2 and 6 h after treatment, respectively. In addition, the proportion of eIF4E mRNA clusters that localize with PSD-95 increases to 74.4 +/- 7.7% and 77.8 +/- 7.6% of the eIF4E clusters at 2 and 6 h after KCl treatment, respectively. Our results demonstrate the presence of eIF4E mRNA in dendrites and an activity-dependent increase of these clusters at synaptic sites. This provides a potential mechanism by which protein translation at synapses may be enhanced in response to synaptic stimulation.
Animals ; Cells, Cultured ; Dendrites/*metabolism ; Eukaryotic Initiation Factor-4E/genetics/*metabolism ; Hippocampus/*cytology ; Immunohistochemistry ; In Situ Hybridization, Fluorescence ; Microscopy, Confocal ; Neurons/cytology/*physiology ; Potassium Chloride/pharmacology ; Protein Biosynthesis ; RNA, Messenger/genetics/*metabolism ; Rats ; Rats, Sprague-Dawley ; Synapses ; *Up-Regulation

OBJECTIVEThis study examined the effect of rapamycin, an inhibitor of mammalian target of rapamycin (mTOR), on eukaryotic initiation factor (eIF- 4E) expression in rat myocardial fibroblasts infected by Coxsackievirus B3 (CVB3) in order to identify the drug target for treatment of viral myocarditis.

METHODSPrimary cultured rat myocardial fibroblasts were treated with CVB3 with multiplicity of infection (MOI=0.5 PFU/cell). The experiment consisted of four groups in which the cultured rat fibroblasts cells were treated with CVB3, rapamycin (10 nM) and CVB3 + rapamycin or placebo (control). Experimental model of CVB3-infected myocardial fibroblasts was confirmed by detection of CVB3 mRNA expression with RT-PCR and observation of morphological changes of the infected cells with microscopy. eIF-4E expression was determined by both RT-PCR and Western Blot methods.

RESULTSMorphological changes were found in the fibroblasts treated with MOI 0.5 PFU/cell of CVB3 by transmission electron microscope and the viral particles were found in the cytoplasm. CVB3 mRNA was expressed in CVB3-infected fibroblasts after 1, 2, and 3 days after infection and 2 days after passage. The gray scale values of the eIF- 4E /beta -actin in the control, the CVB3, the rapamycin and the CVB3+rapamycin groups were 0.73 +/- 0.07, 0.87 +/- 0.03, 0.32 +/- 0.03 and 0.56 +/- 0.04 respectively detected by RT-PCR, and were 0.79 +/- 0.09, 1.35 +/- 0.12, 0.55 +/- 0.04, and 0.62 +/- 0.07 respectively detected by Western blot. EIF- 4E expression in the CVB3 group was higher than that in the control group. Both the rapamycin and the CVB3+rapamycin groups had lower eIF- 4E expression than the control and the CVB3 groups.

CONCLUSIONSCVB3 can infect myocardial fibroblasts and up-regulate the eIF- 4E expression in rat myocardial fibroblasts. Rapamycin can inhibit eIF- 4E expression and may be a potential medicine for treatment of viral myocarditis. It was suspected that mTOR/eIF- 4E signal pathway in rat myocardial fibroblasts might play an important role in the pathogenesis of viral myocarditis.

Animals ; Cells, Cultured ; Enterovirus B, Human ; Enterovirus Infections ; drug therapy ; metabolism ; Eukaryotic Initiation Factor-4E ; genetics ; Fibroblasts ; metabolism ; virology ; Gene Expression Regulation ; drug effects ; Myocarditis ; drug therapy ; etiology ; metabolism ; Myocardium ; metabolism ; Rats ; Sirolimus ; pharmacology ; therapeutic use

OBJECTIVE: To investigate the factors of laryngeal carcinoma recurrence, 103 patients of laryngeal carcinoma were analyzed retrospectively on carcinoma marker, molecular margin and clinical factors with univariate analysis and multivariate analysis. METHOD: CyclinD1, p27, p53 and eIF4E in primary site and surgery margins were detected in laryngeal carcinoma recurrence group and unrecurrence group with immunohistochemical staining to explore the significance of CyclinD1, p27, p53 and eIF4E on laryngeal carcinoma recurrence; The clinical data of 103 patients of laryngeal carcinoma were analyzed retrospectively to investigate the clinical factors of laryngeal carcinoma recurrence; At last above three factors were analyzed with multivariate analysis. RESULT: There was significant difference between laryngeal carcinoma recurrence group and unrecurrence group about CyclinD1, p27 and p53 in laryngeal primary site; There was no significant difference between laryngeal carcinoma recurrence group and unrecurrence group about eIF4E. There was significant difference between laryngeal carcinoma recurrence group and unrecurrence group about CyclinD1, p27, p53 and eIF4E in surgery margins. Laryngeal carcinoma recurrence after surgery was related with carcinoma site, T stage, node metastasis, laryngeal carcinoma pathology and operative method; However, it was not related with age, sex and postoperative irradiation therapy with univariate analysis. Laryngeal carcinoma recurrence after surgery was related with T stage, node metastasis, laryngeal carcinoma pathology and operative method with logistic multivariate analysis. At last, laryngeal carcinoma recurrence after surgery was related with T stage, node metastasis, laryngeal carcinoma pathology and positive molecular margins with logistic multivariate analysis. CONCLUSION The factors of laryngeal carcinoma recurrence is comprehensive. T stage, node metastasis,laryngeal carcinoma pathology and laryngeal carcinoma positive molecular margins were related with laryngeal carcinoma recurrence. Positive molecular margins were more reliable.
Aged ; Aged, 80 and over ; Biomarkers, Tumor ; Carcinoma, Squamous Cell ; genetics ; pathology ; Cyclin D1 ; metabolism ; Cyclin-Dependent Kinase Inhibitor p27 ; metabolism ; Eukaryotic Initiation Factor-4E ; metabolism ; Female ; Humans ; Laryngeal Neoplasms ; genetics ; pathology ; Male ; Middle Aged ; Neoplasm Recurrence, Local ; pathology ; Neoplasm Staging ; Prognosis ; Tumor Suppressor Protein p53 ; metabolism

We investigated how the dual inhibition of the molecular mechanism of the mammalian target of the rapamycin (mTOR) downstreams, P70S6 kinase (P70S6K) and eukaryotic initiation factor 4E (eIF4E), can lead to a suppression of the proliferation and progression of urothelial carcinoma (UC) in an orthotopic mouse non-muscle invasive bladder tumor (NMIBT) model. A KU-7-luc cell intravesically instilled orthotopic mouse NMIBC model was monitored using bioluminescence imaging (BLI) in vivo by interfering with different molecular components using rapamycin and siRNA technology. We then analyzed the effects on molecular activation status, cell growth, proliferation, and progression. A high concentration of rapamycin (10 microM) blocked both P70S6K and elF4E phosphorylation and inhibited cell proliferation in the KU-7-luc cells. It also reduced cell viability and proliferation more than the transfection of siRNA against p70S6K or elF4E. The groups with dual p70S6K and elF4E siRNA, and rapamycin reduced tumor volume and lamina propria invasion more than the groups with p70S6K or elF4E siRNA instillation, although all groups reduced photon density compared to the control. These findings suggest that both the mTOR pathway downstream of eIF4E and p70S6K can be successfully inhibited by high dose rapamycin only, and p70S6K and Elf4E dual inhibition is essential to control bladder tumor growth and progression.
Animals ; Cell Line ; Cell Proliferation/drug effects/genetics ; Cell Survival/drug effects ; Disease Progression ; Eukaryotic Initiation Factor-4E/*antagonists & inhibitors/genetics ; Female ; Mice ; Mice, Nude ; Mucous Membrane/pathology ; Phosphorylation/drug effects ; RNA Interference ; RNA, Small Interfering ; Ribosomal Protein S6 Kinases, 70-kDa/*antagonists & inhibitors/genetics ; Signal Transduction/drug effects ; Sirolimus/*pharmacology ; TOR Serine-Threonine Kinases/*antagonists & inhibitors/metabolism ; Urinary Bladder Neoplasms/genetics/*pathology ; Urothelium/pathology

We investigated how the dual inhibition of the molecular mechanism of the mammalian target of the rapamycin (mTOR) downstreams, P70S6 kinase (P70S6K) and eukaryotic initiation factor 4E (eIF4E), can lead to a suppression of the proliferation and progression of urothelial carcinoma (UC) in an orthotopic mouse non-muscle invasive bladder tumor (NMIBT) model. A KU-7-luc cell intravesically instilled orthotopic mouse NMIBC model was monitored using bioluminescence imaging (BLI) in vivo by interfering with different molecular components using rapamycin and siRNA technology. We then analyzed the effects on molecular activation status, cell growth, proliferation, and progression. A high concentration of rapamycin (10 microM) blocked both P70S6K and elF4E phosphorylation and inhibited cell proliferation in the KU-7-luc cells. It also reduced cell viability and proliferation more than the transfection of siRNA against p70S6K or elF4E. The groups with dual p70S6K and elF4E siRNA, and rapamycin reduced tumor volume and lamina propria invasion more than the groups with p70S6K or elF4E siRNA instillation, although all groups reduced photon density compared to the control. These findings suggest that both the mTOR pathway downstream of eIF4E and p70S6K can be successfully inhibited by high dose rapamycin only, and p70S6K and Elf4E dual inhibition is essential to control bladder tumor growth and progression.
Animals ; Cell Line ; Cell Proliferation/drug effects/genetics ; Cell Survival/drug effects ; Disease Progression ; Eukaryotic Initiation Factor-4E/*antagonists & inhibitors/genetics ; Female ; Mice ; Mice, Nude ; Mucous Membrane/pathology ; Phosphorylation/drug effects ; RNA Interference ; RNA, Small Interfering ; Ribosomal Protein S6 Kinases, 70-kDa/*antagonists & inhibitors/genetics ; Signal Transduction/drug effects ; Sirolimus/*pharmacology ; TOR Serine-Threonine Kinases/*antagonists & inhibitors/metabolism ; Urinary Bladder Neoplasms/genetics/*pathology ; Urothelium/pathology