OBJECTIVETo study the relationship between the expression of serum amyloid A (SAA) and insulin resistance in 3T3-L1 adipocytes.

METHODS3T3-L1 adipocytes were incubated with different concentrations of dexamethasone (10, 100, and 1000 nmol/L) for 48 h to establish cell models of insulin resistance at different resistant levels (models 1, 2, and 3, respectively). The degree of insulin resistance of 3T3-L1 adipocytes was assayed by 2-deoxy-[(3)H]-D-glucose uptake. Semi- quantitative RT-PCR was performed for quantification of SAA mRNA expression. SAA concentrations in the culture medium were determined by ELISA.

RESULTDexamethasone did not affect the basal glucose transport (P>0.05). Insulin-stimulated glucose uptake was significantly decreased by 15% (P<0.05), 40% (P<0.01), and 55% (P<0.01) in models 1, 2, and 3 in comparison with the untreated group, respectively; the expressions of SAA mRNA were upregulated by 2.5 (P<0.01), 3.33 (P<0.01), and 4.08 folds (P<0.01) and SAA concentrations increased by 2.05, 3.13, and 4.23 folds, respectively. The expressions of SAA mRNA were positively correlated to the degree of insulin resistance (r=0.773, P<0.01) and SAA concentration (r=0.832, P<0.01).

CONCLUSIONA cell model of insulin resistance has been established in 3T3-L1 adipocytes by dexamethasone exposure. SAA is closely associated with insulin resistance and may serve as a marker of insulin resistance.

3T3-L1 Cells ; Adipocytes ; metabolism ; Animals ; Deoxyglucose ; metabolism ; Dexamethasone ; pharmacology ; Enzyme-Linked Immunosorbent Assay ; Insulin Resistance ; Mice ; RNA, Messenger ; genetics ; metabolism ; Serum Amyloid A Protein ; genetics ; metabolism

OBJECTIVES: Epilepsy is a syndrome of central nervous system dysfunction caused by many reasons, which is mainly characterized by abnormal discharge of neurons in the brain. Therefore, finding new targets for epilepsy therapy has always been the focus and hotspot in neurological research field. Studies have found that 2-deoxy-D-glucose (2-DG) exerts anti-epileptic effect by up-regulation of K_ATP channel subunit Kir6.1, Kir6.2 mRNA and protein. By using the database of TargetScan and miRBase to perform complementary pairing analysis on the sequences of miRNA and related target genes, it predicted that miR-194 might be the upstream signaling molecule of K_ATP channel. This study aims to explore the mechanism by which 2-DG exerts its anti-epileptic effect by regulating K_ATP channel subunits Kir6.1 and Kir6.2 via miR-194. METHODS: A magnesium-free epilepsy model was established and randomly divided into a control group, an epilepsy group (EP group), an EP+2-DG group, and miR-194 groups (including EP+miR-194 mimic, EP+miR-194 mimic+2-DG, EP+miR-194 mimic control, EP+miR-194 inhibitor, EP+miR-194 inhibitor+2-DG, and EP+miR-194 inhibitor control groups). The 2-DG was used to intervene miR-194 mimics, patch-clamp method was used to detect the spontaneous recurrent epileptiform discharges, real-time PCR was used to detect neuronal miR-194, Kir6.1, and Kir6.2 expressions, and the protein levels of Kir6.1 and Kir6.2were detected by Western blotting. RESULTS: Compared with the control group, there was no significant difference in the amplitude of spontaneous discharge potential in the EP group (P>0.05), but the frequency of spontaneous discharge was increased (P<0.05). Compared with the EP group, the frequency of spontaneous discharge was decreased (P<0.05). Compared with the EP+miR-194 mimic control group, the mRNA and protein expressions of Kir6.1 and Kir6.2 in the EP+miR-194 mimic group were down-regulated (all P<0.05). Compared with the EP+miR-194 inhibitor control group, the mRNA and protein expressions of Kir6.1 and Kir6.2 in the EP+miR-194 inhibitor group were up-regulated (all P<0.05). After pretreatment with miR-194 mimics, the mRNA and protein expression levels of K_ATP channel subunits Kir6.1 and Kir6.2 were decreased (all P<0.05). Compared with the EP+2-DG group, the mRNA and protein expression levels of Kir6.1 and Kir6.2 in the EP+miR-194 mimic+2-DG group were down-regulated (all P<0.05) and the mRNA and protein expression levels of Kir6.1 and Kir6.2 in the EP+miR-194 inhibitor+2-DG group were up-regulated (all P<0.05). CONCLUSIONS The 2-DG might play an anti-epilepsy effect by up-regulating K_ATP channel subunits Kir6.1 and Kir6.2via miR-194.
Adenosine Triphosphate ; Anticonvulsants ; Deoxyglucose/pharmacology* ; Epilepsy/genetics* ; Glucose ; Humans ; MicroRNAs/genetics* ; Potassium Channels, Inwardly Rectifying/metabolism* ; RNA, Messenger/metabolism* ; Signal Transduction

OBJECTIVETo investigate the antineoplastic effects of 2-Deoxy-D-glucose (2-DG) combined with Taxol on orthotopically transplanted breast cancer in C3H mice and explore the mechanism.

METHODSC3H mice bearing orthotopically transplanted breast cancer xenograft were randomly divided into 4 groups, namely the control group, 2-DG group, Taxol group, and 2-DG+Taxol group. The corresponding drugs were administered intraperitoneally every 3 days for 18 consecutive days, and the tumor volume was measured every 3 days to draw the tumor growth curve. The mice were then sacrificed to measure the tumor weight on day 19 and examine tumor cell apoptosis with TUNEL assay and VEGF expression using immunohistochemistry.

RESULTS2-DG combined with Taxol obviously suppressed the tumor growth with a tumor inhibition rate of 66.06% as compared to the rate of 36.97% in Taxol group. The combined treatment also caused more obvious cell apoptosis and significantly reduced VEGF expression in the tumor cells as compared with the other groups.

CONCLUSION2-DG can enhance the inhibitory effect of Taxol on orthotopically transplanted breast cancer xenograft in C3H mice probably by inducing tumor cell apoptosis and lowering VEGF expressions.

Animals ; Antineoplastic Agents ; pharmacology ; therapeutic use ; Apoptosis ; Breast Neoplasms ; drug therapy ; pathology ; Cell Line, Tumor ; Deoxyglucose ; pharmacology ; therapeutic use ; Drug Synergism ; Female ; Mice ; Mice, Inbred C3H ; Paclitaxel ; pharmacology ; therapeutic use ; Vascular Endothelial Growth Factor A ; metabolism ; Xenograft Model Antitumor Assays

OBJECTIVETo investigate the effect of 2-deoxy-D-glucose (2-DG) in enhancing the sensitivity of oral cancer cells to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis.

METHODSThe oral cancer cell line KB was incubated in the presence of different concentrations (0, 0.625, 1.25, 2.5, 5, and 10 mmol/L) of 2-DG with or without TRAIL (200 ng/ml). The cell viability was measured using MTT assay and cell apoptosis was detected using flow cytometry with propidium iodide (PI) staining. KB cells treated with 5 mmol/L 2-DG with or without TRAIL for 0, 6, 16, or 24 h were examined with Western blotting for protein expressions of death receptor 5 (DR5) and caspase-3.

RESULTSTreatment of the cells with 5 mmol/L 2-DG for 24, 48 and 72 h resulted in a cell viability of 25.25%, 69.06%, and 59.19%, respectively. Combined treatment with 5 mmol/L 2-DG with TRAIL for 24 significantly enhanced the cell apoptotic rate (72.5%) as compared to the rate induced by TRAIL alone (45.3%) and by 2-DG (15.9%) alone. 2-DG treatment markedly up-regulated DR5 and caspase-3 expression and enhanced the inhibitory effect of TRAIL on cell colony formation.

CONCLUSION2-DG sensitizes oral cancer cells to TRAIL- induced apoptosis by up-regulating DR5 and caspase-3 expressions.

Apoptosis ; drug effects ; Caspase 3 ; metabolism ; Cell Line, Tumor ; Deoxyglucose ; pharmacology ; Drug Synergism ; Gene Expression Regulation, Neoplastic ; Humans ; Receptors, TNF-Related Apoptosis-Inducing Ligand ; metabolism ; TNF-Related Apoptosis-Inducing Ligand ; pharmacology

This study was purposed to investigate the effects of 2-deoxy-D-glucose (2-DG) on sensitizing HL-60 cells to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis and its possible mechanism. The proliferative inhibition of HL-60 cells treated with different concentrations of 2-DG and TRAIL was measured by MTT assay. The cells were treated with 2-DG, TRAIL, and 2-DG combined with TRAIL at the concentration < IC50 value, i.e. 10 mmol/L for 2-DG and 100 ng/ml for TRAIL. Apoptosis was analyzed by flow cytometry with PI staining; the expression of RIP1, GRP78, and PARP was analyzed by Western blot; the activity of caspase-3 was detected by special detection kit. The results showed that the combined treatment of HL-60 cells for 48 h induced an apoptotic rate of (45.1 ± 4.3)%, which was significantly higher than that of treated with 2-DG or TRAIL alone; at the same time, the combined treatment potentiated the expression of GRP78 and caspase-3 activity, and down-regulated the expression of RIP1. It is concluded that 2-DG can sensitize HL-60 cells to TRAIL-induced apoptosis, which may be correlated with excessive endoplasmic reticulum stress response, down-regulation of RIP1, and increase of caspase-3 activity.
Apoptosis ; drug effects ; Caspase 3 ; metabolism ; Deoxyglucose ; pharmacology ; HL-60 Cells ; Heat-Shock Proteins ; metabolism ; Humans ; Nuclear Pore Complex Proteins ; metabolism ; RNA-Binding Proteins ; metabolism ; TNF-Related Apoptosis-Inducing Ligand ; metabolism ; pharmacology

OBJECTIVETo investigate the role of miR-181c in glycolysis of cancer-associated fibroblasts (CAFs) and explore the mechanism.

METHODSHuman lung CAFs and normal fibroblasts (NFs), isolated from fresh human lung adenocarcinoma tissue specimens by primary culture of tissue explants, were transfected with a miR -181c mimics, a miR-181c inhibitor, a siRNA siRNA-HK2 or the vector HK2-vector via Lipofectamine(TM) 2000. Quantitative real-time PCR was used to analyze the changes in miR-125b expression in the transfected cells; hexokinase-2 (HK2) protein expression in the cells was detected using Western blotting, and the cellular glucose uptake was assessed with 2-NBDG. Lactate production in the cells was examined and expression of HK2 mRNA was detected with dual luciferase reporter gene assay.

RESULTSNo obvious difference was found in the cell morphology between CAFs and NFs. Compared with the NFs, the CAFs showed obviously increased glucose uptake, lactate production and HK2 protein expression with decreased expressions of the miR-181 family (P<0.05). Transfection with the miR-181 inhibito- rsignificantly increased glucose uptake, lactate production and HK2 protein expression in the NFs. In CAFs, transfection with the miR-181 mimics caused significantly lowered glucose uptake, lactate production and HK2 protein expression of. Knockdown of endogenous HK2 by siRNA abolished miR-181 mimics-mediated decrease of glucose uptake and lactate production in CAFs, while transfection with miR-181 mimics suppressed HK2 overexpression-induced enhancement of glucose uptake and lactate production in NFs.

CONCLUSIONTransfection with miR-181 mimics can suppress glycolysis in CAFs by inhibiting HK2 expression.

4-Chloro-7-nitrobenzofurazan ; analogs & derivatives ; Adenocarcinoma ; pathology ; Deoxyglucose ; analogs & derivatives ; Fibroblasts ; drug effects ; Glycolysis ; Hexokinase ; antagonists & inhibitors ; Humans ; Lung Neoplasms ; pathology ; MicroRNAs ; pharmacology ; RNA, Messenger ; RNA, Small Interfering ; Real-Time Polymerase Chain Reaction ; Transfection ; Tumor Cells, Cultured

It has been known that O-linked beta-N-acetylglucosamine (O-GlcNAc) modification of proteins plays an important role in transcription, translation, nuclear transport and signal transduction. The increased flux of glucose through the hexosamine biosynthetic pathway (HBP) and increased O-GlcNAc modification of protein have been suggested as one of the causes in the development of insulin resistance. However, it is not clear at the molecular level, how O-GlcNAc protein modification results in substantial impairment of insulin signaling. To clarify the association of O-GlcNAc protein modification and insulin resistance in rat primary adipocytes, we treated the adipocytes with O-(2-acetamido-2deoxy-D-glucopyranosylidene)amino-N-phenylcarbamate (PUGNAc), a potent inhibitor of O-GlcNAcase that catalyzes removal of O-GlcNAc from proteins. Prolonged treatment of PUGNAc (100 micrometer for 12 h) increased O-GlcNAc modification on proteins in adipocytes. PUGNAc also drastically decreased insulin-stimulated 2-deoxyglucose (2DG) uptake and GLUT4 translocation in adipocytes, indicating that PUGNAc developed impaired glucose utilization and insulin resistance in adipocytes. Interestingly, the O-GlcNAc modification of IRS-1 and Akt2 was increased by PUGNAc, accompanied by a partial reduction of insulin-stimulated phosphorylations of IRS-1 and Akt2. The PUGNAc treatment has no effect on the expression level of GLUT4, whereas O-GlcNAc modification of GLUT4 was increased. These results suggest that the increase of O-GlcNAc modification on insulin signal pathway intermediates, such as IRS-1 and Akt2, reduces the insulin-stimulated phosphorylation of IRS-1 and Akt2, subsequently leading to insulin resistance in rat primary adipocytes.
Acetylglucosamine/*analogs & derivatives/metabolism/pharmacology ; Adipocytes/*metabolism ; Animals ; Deoxyglucose/pharmacokinetics ; Glycosylation ; Immunoprecipitation ; *Insulin Resistance ; Male ; Monosaccharide Transport Proteins/metabolism ; Oximes/*pharmacology ; Phenylcarbamates/*pharmacology ; Phosphoproteins/*metabolism ; Phosphorylation ; Protein-Serine-Threonine Kinases/*metabolism ; Proto-Oncogene Proteins/*metabolism ; Rats ; Rats, Sprague-Dawley ; Research Support, Non-U.S. Gov't ; Subcellular Fractions/metabolism ; beta-N-Acetylhexosaminidase/antagonists & inhibitors

Endoplasmic reticulum (ER) stress regulates a wide range of cellular responses including apoptosis, proliferation, inflammation, and differentiation in mammalian cells. In this study, we observed the role of 2-deoxy-D-glucose (2DG) on inflammation of chondrocytes. 2DG is well known as an inducer of ER stress, via inhibition of glycolysis and glycosylation. Treatment of 2DG in chondrocytes considerably induced ER stress in a dose- and time-dependent manner, which was demonstrated by a reduction of glucose regulated protein of 94 kDa (grp94), an ER stress-inducible protein, as determined by a Western blot analysis. In addition, induction of ER stress by 2DG led to the expression of COX-2 protein with an apparent molecular mass of 66-70kDa as compared with the normally expressed 72-74 kDa protein. The suppression of ER stress with salubrinal (Salub), a selective inhibitor of eif2-alpha dephosphorylation, successfully prevented grp94 induction and efficiently recovered 2DG-modified COX-2 molecular mass and COX-2 activity might be associated with COX-2 N-glycosylation. Also, treatment of 2DG increased phosphorylation of Src in chondrocytes. The inhibition of the Src signaling pathway with PP2 (Src tyrosine kinase inhibitor) suppressed grp94 expression and restored COX-2 expression, N-glycosylation, and PGE2 production, as determined by a Western blot analysis and PGE2 assay. Taken together, our results indicate that the ER stress induced by 2DG results in a decrease of the transcription level, the molecular mass, and the activity of COX-2 in rabbit articular chondrocytes via a Src kinase-dependent pathway.
Animals ; Cartilage, Articular/pathology ; Cells, Cultured ; Chondrocytes/drug effects/immunology/*metabolism/pathology ; Cyclooxygenase 2/genetics/*metabolism ; Deoxyglucose/*pharmacology ; Down-Regulation ; Endoplasmic Reticulum/drug effects/*metabolism/pathology ; Glycosylation/drug effects ; Inflammation ; Rabbits ; Signal Transduction/drug effects ; Stress, Physiological/drug effects/immunology ; src-Family Kinases/*metabolism

2-deoxy-D-glucose (2DG) is known as a synthetic inhibitor of glucose. 2DG regulates various cellular responses including proliferation, apoptosis and differentiation by regulation of glucose metabolism in cancer cells. However, the effects of 2DG in normal cells, including chondrocytes, are not clear yet. We examined the effects of 2DG on dedifferentiation with a focus on the beta-catenin pathway in rabbit articular chondrocytes. The rabbit articular chondrocytes were treated with 5 mM 2DG for the indicated time periods or with various concentrations of 2DG for 24 h, and the expression of type II collagen, c-jun and beta-catenin was determined by Western blot, RT-PCR, immunofluorescence staining and immunohistochemical staining and reduction of sulfated proteoglycan synthesis detected by Alcain blue staining. Luciferase assay using a TCF (T cell factor)/LEF (lymphoid enhancer factor) reporter construct was used to demonstrate the transcriptional activity of beta-catenin. We found that 2DG treatment caused a decrease of type II collagen expression. 2DG induced dedifferentiation was dependent on activation of beta-catenin, as the 2DG stimulated accumulation of beta-catenin, which is characterized by translocation of beta-catenin into the nucleus determined by immunofluorescence staining and luciferase assay. Inhibition of beta-catenin degradation by inhibition of glycogen synthase kinase 3-beta with lithium chloride (LiCl) or inhibition of proteasome with z-Leu-Leu-Leu-CHO (MG132) accelerated the decrease of type II collagen expression in the chondrocytes. 2DG regulated the post-translational level of beta-catenin whereas the transcriptional level of beta-catenin was not altered. These results collectively showed that 2DG regulates dedifferentiation via beta-catenin pathway in rabbit articular chondrocytes.
Animals ; Cartilage, Articular/*cytology ; Cell Dedifferentiation/*drug effects ; Cell Nucleus/drug effects/metabolism ; Chondrocytes/*cytology/drug effects/enzymology/*metabolism ; Deoxyglucose/*pharmacology ; Endoplasmic Reticulum/drug effects/pathology ; Glycogen Synthase Kinase 3/metabolism ; Mutant Proteins/metabolism ; Protein Transport/drug effects ; Proteoglycans/metabolism ; Rabbits ; Signal Transduction/*drug effects ; beta Catenin/*metabolism