Up-frameshift 1 (UPF1), as the most critical factor in nonsense-mediated messenger RNA (mRNA) decay (NMD), regulates tumor-associated molecular pathways in many cancers. However, the role of UPF1 in lung adenocarcinoma (LUAD) amino acid metabolism remains largely unknown. In this study, we found that UPF1 was significantly correlated with a portion of amino acid metabolic pathways in LUAD by integrating bioinformatics and metabolomics. We further confirmed that UPF1 knockdown inhibited activating transcription factor 4 (ATF4) and Ser51 phosphorylation of eukaryotic translation initiation factor 2α (eIF2α), the core proteins in amino acid metabolism reprogramming. In addition, UPF1 promotes cell proliferation by increasing the amino-acid levels of LUAD cells, which depends on the function of ATF4. Clinically, UPF1 mRNA expression is abnormal in LUAD tissues, and higher expression of UPF1 and ATF4 was significantly correlated with poor overall survival (OS) in LUAD patients. Our findings reveal that UPF1 is a potential regulator of tumor-associated amino acid metabolism and may be a therapeutic target for LUAD.
Activating Transcription Factor 4/genetics* ; Adenocarcinoma of Lung ; Amino Acids ; Cell Proliferation ; Eukaryotic Initiation Factor-2 ; Humans ; Lung Neoplasms ; RNA Helicases/metabolism* ; RNA, Messenger/metabolism* ; Trans-Activators/metabolism*

OBJECTIVE: Autophagy is a highly conserved intracellular degradation pathway. Many picornaviruses induce autophagy to benefit viral replication, but an understanding of how autophagy occurs remains incomplete. In this study, we explored whether coxsackievirus B3 (CVB3) infection induced autophagy through endoplasmic reticulum (ER) stress. METHODS: In CVB3-infected HeLa cells, the specific molecules of ER stress and autophagy were detected using Western blotting, reverse transcription polymerase chain reaction (RT-PCR), and confocal microscopy. Then PKR-like ER protein kinase (PERK) inhibitor, inositol-requiring protein-1 (IRE1) inhibitor, or activating transcription factor-6 (ATF6) inhibitor worked on CVB3-infected cells, their effect on autophagy was assessed by Western blotting for detecting microtubule-associated protein light chain 3 (LC3). RESULTS: CVB3 infection induced ER stress, and ER stress sensors PERK/eIF2α, IRE1/XBP1, and ATF6 were activated. CVB3 infection increased the accumulation of green fluorescent protein (GFP)-LC3 punctuation and induced the conversion from LC3-I to phosphatidylethanolamine-conjugated LC3-1 (LC3-II). CVB3 infection still decreased the expression of mammalian target of rapamycin (mTOR) and p-mTOR. Inhibition of PERK, IRE1, or ATF6 significantly decreased the ratio of LC3-II to LC3-I in CVB3-infected HeLa cells. CONCLUSION CVB3 infection induced autophagy through ER stress in HeLa cells, and PERK, IRE1, and ATF6a pathways participated in the regulation of autophagy. Our data suggested that ER stress may inhibit mTOR signaling pathway to induce autophagy during CVB3 infection.
Activating Transcription Factor 6 ; metabolism ; Autophagy ; Coxsackievirus Infections ; metabolism ; Endoplasmic Reticulum Stress ; Endoribonucleases ; metabolism ; Enterovirus B, Human ; HeLa Cells ; Humans ; Protein-Serine-Threonine Kinases ; metabolism ; Signal Transduction ; eIF-2 Kinase ; metabolism

PURPOSE: Lithium-pilocarpine induced status epilepticus (LPSE) causes selective and age-dependent neuronal death, although the mechanism of maturation-related injury has not yet been clarified. The activating transcription factor-2 (ATF-2) protein is essential for the normal development of mammalian brain and is activated by c-Jun N-terminal kinase (JNK). It induces the expression of the c-jun gene and modulates the function of the c-Jun protein, a mediator of neuronal death and survival. Therefore, we investigated the expression of c-Jun and ATF-2 protein in the immature and adult rat hippocampus to understand their roles in LPSE-induced neuronal death. MATERIALS AND METHODS: Lithium chloride was administrated to P10 and adult rats followed by pilocarpine. Neuronal injury was assessed by silver and cresyl violet staining, performed 72 hours after status epilepticus. For evaluation of the expression of ATF-2 and c-Jun by immunohistochemical method and Western blot, animals were sacrificed at 0, 4, 24, and 72 hours after the initiation of seizure. RESULTS: Neuronal injury and expression of c-Jun were maturation-dependently increased by LPSE, whereas ATF-2 immunoreactivity decreased in the mature brain. Since both c-Jun and ATF-2 are activated by JNK, and targets and competitors in the same signal transduction cascade, we could speculate that ATF-2 may compete with c-Jun for JNK phosphorylation. CONCLUSION: The results suggested a neuroprotective role of ATF-2 in this maturation-related evolution of neuronal cell death from status epilepticus.
Activating Transcription Factor 2/*metabolism ; Animals ; Antimanic Agents/pharmacology ; Blotting, Western ; Hippocampus/drug effects/*metabolism ; Immunohistochemistry ; Lithium/pharmacology ; Miotics/pharmacology ; Pilocarpine/pharmacology ; Proto-Oncogene Proteins c-jun/*metabolism ; Rats ; Status Epilepticus/*chemically induced

PURPOSE: To investigate the anti-apoptotic mechanism of leptin in non-small cell lung cancer. MATERIALS AND METHODS: The influences of leptin on apoptosis were investigated, analyzing the mechanism that triggers growth of A549 cells. The effects of leptin on cell proliferation were examined by XTT analysis. Leptin, C/EBP homologous protein (CHOP), phosphorylated-PKR-like ER kinase (p-Perk), inositol requiring proteins-1, spliced X-box transcription factor-1 (XBP1), cleaved activating transcription factor-6 (ATF6), eukaryotic translation initiation factor-2alpha, caspase-12 and CHOP protein were detected in four groups by western blot, and endoplasmic reticulum (ER) stress related mRNA were detected by reverse transcription PCR. RESULTS: The expression of leptin in A549 and leptin transfected cells inhibited cisplatin activated ER stress-associated mRNA transcription and protein activation. Two ER stress unfolded protein response pathways, PERK and ATF6, were involved, and XBP1 and tumor necrosis factor receptor-associated factor 2 (TRAF2) were increased significantly when treated with cisplatin in A549-siRNA against leptin cells. Furthermore, CHOP expression was inhibited upon leptin expression in A549, LPT-PeP and LPT-EX cells. CONCLUSION: Leptin serves as an important factor that promotes the growth of A549 cells through blocking ER stress-mediated pathways. This blocking is triggered by p-Perk and ATF6 via inhibition of CHOP expression.
Activating Transcription Factor 6/genetics/*metabolism ; Apoptosis/*drug effects/genetics ; Blotting, Western ; Cell Line, Tumor ; Cell Proliferation/*drug effects ; Humans ; Leptin/*pharmacology ; Reverse Transcriptase Polymerase Chain Reaction ; eIF-2 Kinase/*metabolism

OBJECTIVETo study the effect of Jianpi Jiedu Recipe (JJR) on the expression of cyclooxygenase (COX-2) in Helicobacter pylori (Hp) infected gastric cancer cell line MKN 45, and its regulatory mechanism of p38MAPK signal transduction.

METHODSThe expressions of COX-2 mRNA and protein in human gastric cancer cell line MKN 45 infected by Hp type strain NCTC 11637 and the regulatory effect of JJR containing serum were detected using Real-time fluorescent quantitative polymerase chain reaction (RFQ-PCR) and Western blot. The effects of Hp on COX-2 mRNA and protein expressions in human gastric cancer cell line MKN 45 were observed using blocking p38MAPK signal transduction pathway by p38MAPK specific inhibitor SB203580. The effects of JJR on Hp-infection activated p38MAPK signal transduction pathway and its downstream activating transcription factor 2 (ATF-2) were observed.

RESULTSCOX-2 mRNA and protein expressions were obviously higher after human gastric cancer cell line MKN 45 were infected by Hp (P<0.01). After blocking p38MAPK signal transduction pathway, COX-2 mRNA and protein expressions in Hp-induced MKN 45 cell line were obviously down-regulated (P<0.01). JJR containing serum down-regulated Hp-induced COX-2 mRNA and protein expressions in MKN 45 cell line in a dose dependent manner. Besides, it could inhibit the activation of Hp-induced p38MAPK signal pathway. It also showed obvious inhibition on the activity of its downstream transcription factor ATF-2.

CONCLUSIONSHp infection induced COX-2 expressions of gastric cancer cells via p38MAPK signal transduction pathway. JJR inhibited Hp-induced the expression of COX-2 through regulating p38MAPK/ATF-2 signal transduction pathway, which may be one of its mechanisms in prevention and treatment of Hp-induced gastric cancer.

Activating Transcription Factor 2 ; metabolism ; Animals ; Cell Line, Tumor ; Cyclooxygenase 2 ; metabolism ; Drugs, Chinese Herbal ; pharmacology ; Gene Expression Regulation, Neoplastic ; Helicobacter pylori ; drug effects ; Humans ; Imidazoles ; pharmacology ; MAP Kinase Signaling System ; drug effects ; Pyridines ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Serum ; Signal Transduction ; drug effects ; Stomach Neoplasms ; metabolism ; microbiology ; p38 Mitogen-Activated Protein Kinases ; antagonists & inhibitors

Expression of protein kinase C-delta (PKC delta) is up-regulated by apoptosis-inducing stimuli. However, very little is known about the signaling pathways that control PKC delta gene transcription. In the present study, we demonstrate that JNK stimulates PKC delta gene expression via c-Jun and ATF2 in response to the anticancer agent doxorubicin (DXR) in mouse lymphocytic leukemia L1210 cells. Luciferase reporter assays showed that DXR-induced activation of the PKC delta promoter was enhanced by ectopic expression of JNK1, c-Jun, or ATF2, whereas it was strongly reduced by expression of dominant negative JNK1 or by treatment with the JNK inhibitor SP600125. Furthermore, point mutations in the core sequence of the c-Jun/ATF2 binding site suppressed DXR-induced activation of the PKC delta promoter. Our results suggest an additional role for a JNK signaling cascade in DXR-induced PKC delta gene expression.
Activating Transcription Factor 2/*physiology ; Animals ; Anthracenes/pharmacology ; Antibiotics, Antineoplastic/*pharmacology ; Apoptosis ; Cell Line, Tumor ; Doxorubicin/*pharmacology ; Mice ; Mitogen-Activated Protein Kinase 8/*physiology ; Mutation ; Promoter Regions, Genetic ; Protein Kinase C-delta/genetics/*metabolism ; Proto-Oncogene Proteins c-jun/antagonists & inhibitors/*physiology ; Signal Transduction/physiology ; Transcription, Genetic

Wnt5a is a ligand that activates the noncanonical Wnt signaling pathways (beta-catenin-independent pathways). Human neutrophils expressed several Wnt5a receptors, such as Frizzled 2, 5 and 8. Stimulation of human neutrophils with Wnt5a caused chemotactic migration and the production of two important chemokines, CXCL8 and CCL2. CCL2 production by Wnt5a was mediated by a pertussis toxin-sensitive G-protein-dependent pathway. Wnt5a also stimulated the phosphorylation of three mitogen-activated protein kinases (MAPKs: ERK, p38 MAPK and JNK) and Akt. Inhibition of ERK, p38 MAPK or JNK by specific inhibitors induced a dramatic reduction in Wnt5a-induced CCL2 production. Supernatant collected from lipopolysaccharide-stimulated macrophages induced neutrophil chemotaxis, which was significantly inhibited by anti-Wnt5a antibody. Our results suggested that Wnt5a may contribute to neutrophil recruitment, mediating the inflammation response.
Activating Transcription Factor 2/metabolism ; Animals ; Cell Separation ; Chemokines/*biosynthesis ; Chemotaxis/*drug effects ; Culture Media, Conditioned/pharmacology ; Extracellular Signal-Regulated MAP Kinases/metabolism ; GTP-Binding Proteins/metabolism ; Humans ; JNK Mitogen-Activated Protein Kinases/metabolism ; Lipopolysaccharides/pharmacology ; Macrophages/drug effects/metabolism ; Mice ; NF-kappa B/metabolism ; Neutrophils/*cytology/drug effects/enzymology/*metabolism ; Pertussis Toxin/pharmacology ; Phosphatidylinositol 3-Kinases/metabolism ; Proto-Oncogene Proteins c-akt/metabolism ; Receptors, Wnt/metabolism ; Type C Phospholipases/metabolism ; Wnt Proteins/*pharmacology ; p38 Mitogen-Activated Protein Kinases/metabolism

OBJECTIVETo study the role of antenatal glucocorticoid (dexamethasone and betamethasone) on bone morphogenetic protein (BMP) signal transduction of the rat fetal lungs.

METHODSFifteen pregnant rats were randomly divided into five groups: the rats treated with dexamethasone for 1 day (1D-DEX) or 3 days (3D-DEX), with betamethasone for 1 day (1D-BEX) or 3 days (3D-BEX) or with normal saline (control group), followed cesarean section on the 19th day of gestation. The mRNA levels of BMP4, BMPR-II, Smad1 and ATF-2 of fetal rat lungs were ascertained by reverse transcriptase polymerase chain reaction (RT-PCR). The expression of BMP4, BMPR-II, Smad1 and ATF-2 antigen expression in fetal lungs was assessed by immune histochemical staining. The expression of BMP4 and BMPR-II was determined by Western blot.

RESULTSThe levels of BMP4, BMPR-II and Smad1 mRNA expression were up-regulated in the 1D-BEX, 3D-BEX and 3D-DEX groups compared with those in the control group (P<0.05). The immune histochemiscal analysis showed that the expression of BMP4, BMPR-II, Phospho-Smad1 (pSmad1) and ATF-2 in the 1D-BEX, 3D-BEX and 3D-DEX groups was significantly higher than that in the control group (P<0.01). The results of Western blot demonstrated that the expression of BMP4 and BMPR-II protein increased significantly in the 1D-BEX, 3D-BEX and 3D-DEX groups when compared with the control group (P<0.01).

CONCLUSIONSBetamethasone and dexamethasone may play important roles in the regulation of BMP signal transduction in the rat fetal lungs. Up-regulation of BMP4, BMPR-II and Smad1 might be one of crucial factors for the glucocorticoid-induced maturity of fetal lungs.

Activating Transcription Factor 2 ; analysis ; genetics ; Animals ; Betamethasone ; pharmacology ; Bone Morphogenetic Protein 4 ; analysis ; genetics ; physiology ; Bone Morphogenetic Protein Receptors, Type II ; analysis ; genetics ; Dexamethasone ; pharmacology ; Female ; Fetus ; drug effects ; metabolism ; Lung ; drug effects ; metabolism ; Pregnancy ; Rats ; Rats, Sprague-Dawley ; Reverse Transcriptase Polymerase Chain Reaction ; Signal Transduction ; drug effects ; Smad1 Protein ; analysis ; genetics

OBJECTIVE: To examine the effect of HPV-16 E6 expression on the transcription of cellular genes, we used cDNA microarray in HPV-16 E6 transfected stable cancer cell lines. METHODS: Using cDNA microarray consisting of 1,024 genes, we have performed a systematic characterization of gene expression in A549E6 human lung adenocarcinoma and RC10.1 human colon adenocarcinoma cell lines stably expressing HPV-16 E6 gene. The up-regulated and down-regulated genes were classified into the different functional categories; oncogenes, apoptosis, cell cycle, signal transduction, gene regulation, immune response, cell adhesion, protein transport, metabolism, redox control and angiogenesis. RESULTS: Among 1,024 known genes and ESTs (expressed sequence tags) tested, we found 27 up- regulated and 43 down-regulated genes in A549E6 (HPV-16 E6) compared to A549. The major up-regulated genes were as follows. GTPase-activating protein Rho 4, transcription factor D2, IKAROS, integrin-alpha 6, cadherin 11, ephrin-beta 2, RAN binding protein 2, branched-chain amino transferase 2. The major down-regulated genes were as follows. K-ras 2, CDC (cell division cycle) 37, CDC16, CDC7L1, IRF3, interferon-gamma-inducible protein 30, cadherin 6, desmoglein 1, desmocollin 2, endothelin 2. Also, we found 48 up-regulated and 34 down-regulated genes in RC10.1 (HPV-16 E6) compared to RKO. The major up-regulated genes were as follows. Colon cancer familial nonpolyposis type 1 (COCA 1), Bcl 2, jagged 1, MAP2K6, E2F1, ephrin receptor-beta 2, ephrin-beta 2, desmoglein 1, transforming growth factor-beta 3. The major down-regulated genes were as follows. KIT, Rad51C, Bcl 2 antagonist killer 1, STAT 4, epidermal growth factor receptor, high mobility group protein 2, cadherin 11, cadherin 12, cadherin 3, integrin-alpha 1, intergrin-alpha 8, chromosome segregation 1-like. CONCLUSION: Various expression patterns of cellular genes by HPV-16 E6 could be wholy grasped and classified into different functional groups using both cell line system stably expressed HPV-16 E6 and cDNA microarray analysis. These analysis methods must be helpful to understand multiple effects of a specific gene on cellular genes in a short period.
Adenocarcinoma ; Apoptosis ; Cadherins ; Carrier Proteins ; Cell Adhesion ; Cell Cycle ; Cell Line ; Centers for Disease Control and Prevention (U.S.) ; Chromosome Segregation ; Colon ; Colonic Neoplasms ; Desmoglein 1 ; DNA, Complementary* ; Endothelin-2 ; Expressed Sequence Tags ; Gene Expression* ; GTPase-Activating Proteins ; Hand Strength ; Human papillomavirus 16* ; Humans ; Lung ; Metabolism ; Oligonucleotide Array Sequence Analysis* ; Oncogenes ; Oxidation-Reduction ; Protein Transport ; Receptor, Epidermal Growth Factor ; Signal Transduction ; Transcription Factors ; Transferases