High Expression of EIF4G2 Mediated by the TUG1/Hsa-miR-26a-5p Axis Is Associated with Poor Prognosis and Immune Infiltration of Gastric Cancer.

Objective: Eukaryotic translation initiation factor 4 gamma 2 (EIF4G2) is involved in the occurrence and development of various tumors. However, the effect of EIF4G2 in gastric cancer (GC) has not been fully explored. The purpose of this study was to explore the function and mechanism of EIF4G2 in GC. Methods: The Tumor Immune Estimation Resource 2.0 database was used to analyze EIF4G2 expression in various cancers and the relationship between EIF4G2 expression and tumor-infiltrating immune cells. Gene Expression Profiling Interactive Analysis was utilized to assess the EIF4G2 expression level and its effect on survival in GC. UALCAN was conducted to analyze EIF4G2 expression in various subgroups of GC. The Kaplan-Meier plotter was employed for survival analysis. Receiver operator characteristic (ROC) curve analysis was applied to evaluate the diagnostic role of EIF4G2 in GC. LinkedOmics was used to identify the co-expressed genes and Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathways. The Tumor-Immune System Interaction database was employed to analyze the correlation between EIF4G2 expression and tumor-infiltrating lymphocytes. The starBase web platform was used to predict the upstream microRNAs and long noncoding RNAs. Results: EIF4G2 expression was upregulated in GC tissues compared to normal controls. High expression of EIF4G2 indicated poor prognosis in GC. ROC analysis revealed that EIF4G2 had good diagnostic ability to distinguish GC from normal tissues. Immune infiltration analysis indicated that EIF4G2 expression may be involved in the modulation of tumor immune infiltration in GC. Finally, we determined that the Taurine Upregulated 1 (TUG1)/hsa-miR-26a-5p/EIF4G2 axis was the most likely regulatory pathway involved in GC development. Conclusions: EIF4G2 was upregulated in GC and elevated expression of EIF4G2 indicated unfavorable prognosis. Moreover, EIF4G2 expression may be involved in the regulation of tumor immune cell infiltration. The TUG1/hsa-miR-26a-5p axis is a likely upstream regulatory mechanism of EIF4G2 in GC. EIF4G2 may thus serve as a prognosis biomarker and present a new therapeutic target.

HNF1α Controls Liver Lipid Metabolism and Insulin Resistance via Negatively Regulating the SOCS-3-STAT3 Signaling Pathway.

This study is aimed at evaluating the effects, functions, and mechanism of HNF1α on hepatic glycolipid metabolism. In this study, free fatty acid- (FFA-) induced steatosis of hepatocyte liver cell LO2 was used as an in vitro model. The methods of Oil Red O staining, RT-qPCR, western blot, and immunofluorescence staining were used to detect LO2-regulated HNF1α expression and its effects on FFA-induced LO2 cell steatosis, the insulin signaling and SOCS-3-STAT3 signaling pathways, the expression of lipid metabolism-related regulators, and phosphorylation. With increased FFA induction time, the expression of HNF1α in the LO2 fatty degeneration hepatic cells gradually decreased. Downregulation of HNF1α expression aggravated FFA-induced steatosis of LO2 hepatocytes. HNF1α promotes activation of the insulin pathway and oxidative breakdown of fat and inhibits lipid anabolism. Inhibitors of STAT3 can reverse the regulation of decreased HNF1α expression on the insulin signaling pathway and fat metabolism. We also confirmed this pathway using HNF1α-/- mice combining treatment with STAT3 inhibitor NSC 74859 in vivo. HNF1α regulates hepatic lipid metabolism by promoting the expression of SOCS-3 and negatively regulating the STAT3 signaling pathway.

Expression of N-acetylglucosaminyltransferase V in gastric cancer correlates with metastasis and prognosis.

N-acetylglucosaminyltransferase V (GnT-V) is an enzyme that catalyzes ß1-6 branching of N-acetylglucosamine on asparagine (N)-linked oligosaccharides (N-glycan) of cell proteins and the dysfunction of which is a common feature of various carcinomas. Nevertheless, the role of GnT-V remains controversial. Therefore, the clinical implication of GnT-V expression may differ in each cancer type. The implication of GnT-V status in patients with gastric cancer has not been studied extensively. In the present study, we examined GnT-V expression in gastric cancer specimen both at protein and mRNA levels. We compared GnT-V expression with clinical and pathologic variables. Kaplan-Meier survival curves were generated to show the cause-specific survival. Furthermore, the small interfering RNA was devised to downregulate the GnT-V mRNA expression in SGC7901 and BGC 823 cells. We characterized the function implication of GnT-V by cell proliferation and invasiveness analysis. Analysis in gastric cancer specimen revealed that GnT-V expression correlated with tumor grade and stage. The overall survival time of positive GnT-V expression in gastric cancer was significantly shorter than that of negative GnT-V expression. Moreover, the downregulation of GnT-V expression by small interfering RNA resulted in a decrease of cell proliferation and invasiveness in SGC7901 and BGC 823 cells accompanied by morphological change. This supports that GnT-V correlates with metastasis and prognosis in gastric cancer. These results contribute to new insight into the underlying molecular mechanisms of GnT-V regulation in gastric cancer with potential translational clinical applications.

Downregulation of the GnT-V gene inhibits metastasis and invasion of BGC823 gastric cancer cells.

Metastatic and invasive potential is a barrier to the successful treatment of gastric cancer. N-acetylgluco-saminyltransferase V (GnT-V), a key enzyme catalyzing the formation of 1,6 N-acetylglucosamine (GlcNAc), has been demonstrated to display a distinct function in different types of tumors. The aim of this study was to investigate the role of GnT-V in the invasive potential of BGC823 human gastric cancer cells in vitro and the possible underlying mechanism. GnT-V was downregulated in BGC823 cells by oligo-siRNA transfection. Cell proliferation and invasiveness were assessed by CCK-8 assay, Tunel assay, scratch-wound assay as well as transwell assay. The products of GnT-V, ß1-6 branching of asparagine-linked oligosaccharides, were determined by L-PHA lectin blot analysis. The expression of EGFRs, E-cadherin/vimentin and MMP-2/MMP-9 was analyzed both at the mRNA and protein levels. The results showed that downregulation of GnT-V decreased proliferation and the metastatic/invasive potential of BGC823 cells. The expression of EGFRs, E-cadherin/vimentin and MMP-9, molecules related to cancer metastasis and invasion in various tumors, were influenced correspondingly. These findings suggest that downregulation of GnT-V inhibited cell metastasis and invasion of BGC823 cells via EGFR signaling-initiated EMT phenotype and MMP-9 expression. These results provide a novel mechanism to explain the role of GnT-V in cell metastasis and invasion.

TFF1 inhibits proliferation and induces apoptosis of gastric cancer cells in vitro.

Trefoil Factor Family (TFF) plays an essential role in the intestinal epithelial restitution, but the relationship between TFF1 and gastric cancer (GC) is still unclear. The present study aimed to determine the role of TFF1 in repairing gastric mucosa and in the pathogenesis of GC. The TFF1 expression in different gastric mucosas was measured with immunohistochemistry. Then, siRNA targeting TFF1 or plasmids expressing TFF1 gene were transfected into BGC823 cells, SGC7901 cells and GES-1 cells. The cell proliferation was detected with MTT assay and apoptosis and cell cycle measured by flow cytometry. From normal gastric mucosa to mucosa with dysplasia and to gastric cancer, the TFF1 expression had a decreasing trend. Down-regulation of TFF1 expression significantly reduced the apoptosis of three cell lines and markedly facilitated their proliferation but had no significant effect on cell cycle. Over-expression of TFF1 could promote apoptosis of three cell lines and inhibit proliferation but had no pronounced effect on cell cycle. TFF1 can inhibit proliferation and induce apoptosis of GC cells in vitro.

Effect of bone morphogenetic protein-2 on proliferation and apoptosis of gastric cancer cells.

OBJECTIVE: To investigate the effects of bone morphogenetic protein-2 (BMP-2) on the proliferation, differentiation and apoptosis of normal human gastric mucosal cells and gastric cancer cells. METHODS: Poorly differentiated gastric cancer BGC823 cells, moderately differentiated gastric cancer cells and normal human gastric mucosal epithelial GES-1 cells were independently treated with recombinant human BMP-2 or its inhibitor Noggin. MTT assay was performed to detect the proliferation, flow cytometry done to measure the cell cycle and apoptosis and immunohistochemistry carried out to determine the expression of cyclin-dependent kinase 4 (CDK4). RESULTS: BMP-2 exerted inhibitory effect on the growth of all types of cells and the inhibition become more evident with the increase of BMP-2 dose. After treatment with 200 ng/ml BMP-2, cancer cells arrested in G1 phase and those in S phase reduced. Gastric cancer cells had higher CDK4 expression than GES-1 cells. BMP-2 decreased CDK-4 expression in cancer cells but had no influence in GES-1 cells. Noggin conferred promotive effect on the growth of 3 types of cells. In 2 types of cancer cells, treatment with 2000 ng/ml Noggin significantly increased the proportion of cells in S phase but reduced that in G1 phase. However, Noggin did not affect the cell cycle of GES-1 cells. The CDK4 expression was markedly increased in 2 types of cancer cells but that of GES-1 remained unchanged after treatment with 2000 ng/ml Noggin. CONCLUSIONS: BMP-2 may inhibit the proliferation of both normal and malignant gastric epithelial cells, down-regulate CDK4 expression in gastric cancer cells and arrest gastric cancer cells in G1-phase in cell cycle. Through antagonizing BMP-2, Noggin, may accelerate the proliferation of gastric cancer cells. Thus, the abnormality of BMP signaling pathway may play an important role in the pathogenesis of gastric cancer.