Animals ; Eukaryotic Initiation Factors ; genetics ; metabolism ; Humans ; Phosphorylation ; physiology ; Proteomics ; Ribosomal Proteins ; genetics ; metabolism ; TOR Serine-Threonine Kinases ; genetics ; metabolism

Eukaryotic translation initiation factor 4B (eIF4B) plays an important role in mRNA translation initiation, cell survival and proliferation in vitro, but the in vivo function is poorly understood. In this study, via various experimental techniques such as hematoxylin-eosin (HE) staining, flow cytometry, Western blotting, and immunohistochemistry, we investigated the role of eIF4B in mouse embryo development using an eIF4B knockout (KO) mouse model and explored the mechanism. We found that the livers, but not lungs, brain, stomach, or pancreas, derived from eIF4B KO mouse embryos displayed severe pathological changes characterized by enhanced apoptosis and necrosis. Accordingly, high expression of cleaved-caspase 3, and excessive activation of mTOR signaling as evidenced by increased expression and phosphorylation of p70S6K and enhanced phosphorylation of 4EBP1, were observed in mouse embryonic fibroblasts and fetal livers from eIF4B KO mice. These results uncover a critical role of eIF4B in mouse embryo development and provide important insights into the biological functions of eIF4B in vivo.
Animals ; Apoptosis/genetics* ; Caspase 3 ; Eosine Yellowish-(YS) ; Eukaryotic Initiation Factors/metabolism* ; Fibroblasts ; Hematoxylin ; Liver/metabolism* ; Mice ; Ribosomal Protein S6 Kinases, 70-kDa/genetics* ; TOR Serine-Threonine Kinases

OBJECTIVEThe aim of this study was to investigate the expression and significance of P311 and ITGB4BP in non-small cell lung cancer (NSCLC).

METHODSTissue microarrays were prepared from 80 NSCLC specimens and examined by immunohistochemistry.

RESULTSThe positive rates of P311 and ITGB4BP expression were 77.5% (62/80) and 82.5% (66/80), respectively. The double positive expression rate was 73.8% (59/80). The consistency rate was 87.5%, and there was a significant consistency between P311 and ITGB4BP expressions (Kappa = 0.611, P < 0.001).

CONCLUSIONThere may be a new signaling pathway P311-ITGB4BP in NSCLC, and it may regulate the lung cancer cell migration.

Adenocarcinoma ; metabolism ; Carcinoma, Non-Small-Cell Lung ; metabolism ; Carcinoma, Squamous Cell ; metabolism ; Eukaryotic Initiation Factors ; metabolism ; Humans ; Immunohistochemistry ; Lung Neoplasms ; metabolism ; Nerve Tissue Proteins ; metabolism ; Oncogene Proteins ; metabolism ; Paraffin Embedding ; Signal Transduction ; Tissue Array Analysis

OBJECTIVETo analyze the relationship between malignant transformation and abnormal expression of eukaryotic initiation factor 3 (eIF3 p36) in human bronchial epithelial (16HBE) cells induced by cadmium chloride (CdCl2).

METHODS16HBE cells were treated several times with different concentrations of CdCl2. Tumorigenic potential of transformed cells was identified by assays for anchorage-independent growth in soft agar and for tumorigenicity in nude mice after the 35th passage. Total RNA was isolated from 16HBE cells induced by CdCl2, including non-transformed, Cd-transformed, and Cd-tumorigenic cell lines. Special primers for eIF3 p36 were designed and the expression of eIF3 mRNA in different cell lines was detected with fluorescent quantitative-polymerase chain reaction technique (FQ-PCR).

RESULTSThe 35th passage of 16HBE cells transformed by CdCl2 exhibited overlapping growth. Compared with the non-transformed cells, colonies of transformed cell lines in soft agar showed statistically significant increases and dose-dependent effects (P<0.01). All Cd-induced transformed cell lines formed tumors in nude mice within 2 weeks of inoculation, but none of the mice injected with non-transformed cells showed tumors even after 3 weeks. All tumors were pathologically identified as poorly differentiated squamous cell carcinoma. The eIF3 p36 genes in different stages of 16HBE cells transformed by CdCl2 were elevated as compared with the non-transformed control (P<0.01), and the eIF3 expression increased with the degree of cell malignancy.

CONCLUSIONCdCl2 is capable of inducing morphological transformation in 16HBE cells and transformed cells are potentially tumorigenic. Over-expression of eIF3 p36 is positively correlated with malignant transformation of 16HBE cells induced by CdCl2 and may be one of the molecular mechanisms potentially responsible for carcinogenesis due to Cd.

Animals ; Base Sequence ; Bronchi ; cytology ; drug effects ; metabolism ; Cadmium Chloride ; pharmacology ; Cell Transformation, Neoplastic ; DNA Primers ; Epithelial Cells ; drug effects ; metabolism ; Eukaryotic Initiation Factors ; metabolism ; Humans ; Mice ; Mice, Nude ; Polymerase Chain Reaction

Evidences show that eukaryotic mRNAs can perform protein translation through internal ribosome entry sites (IRES). 5'-Untranslated region of the mRNA encoding apoptotic protease-activating factor 1 (Apaf-1) contains IRES, and, thus, can be translated in a cap-independent manner. Effects of changes in protein translation pattern through rapamycin pretreatment on 4-(methylnitrosamino)-1-(3-pyridyl)-butanone(NNK, tobacco-specific lung carcinogen)-induced apoptosis in human bronchial epithelial cells were examined by caspase assay, FACS analysis, Western blotting, and transient transfection. Results showed that NNK induced apoptosis in concentration- and time-dependent manners. NNK-induced apoptosis occurred initially through cap-independent protein translation, which during later stage was replaced by cap-dependent protein translation. Our data may be pplicable as the mechanical basis of lung cancer treatment.
Antibiotics, Antineoplastic/pharmacology ; Apoptosis/*drug effects ; Apoptotic Protease-Activating Factor 1 ; BH3 Interacting Domain Death Agonist Protein ; Blotting, Western ; Bronchi/metabolism/*pathology ; Carcinogens/*pharmacology ; Carrier Proteins/metabolism ; Caspases/metabolism ; Cytochromes c/metabolism ; Dose-Response Relationship, Drug ; Epithelial Cells/metabolism/*pathology ; Eukaryotic Initiation Factor-4E/metabolism ; Flow Cytometry ; Humans ; Nitrosamines/*pharmacology ; Protein Biosynthesis ; Proteins/metabolism ; Proto-Oncogene Proteins c-bcl-2/metabolism ; RNA Cap-Binding Proteins/*physiology ; Sirolimus/pharmacology ; Time Factors ; bcl-2-Associated X Protein