OBJECTIVETo study the inhibition effect of HCV NS5A on p53 protein transactivity and its possible mechanism.

METHODSLuciferase reporter gene system was used for the study of p53 transactivity on p21 promoter and electrophorectic mobility-shift assay (EMSA) was applied to observe whether HCV NS5A could suppress the binding ability of p53 protein to its specific DNA sequence.

RESULTSEndogenous p53 protein could stimulate p21 promoter activity, and the relative luciferase activity increased significantly (3.49 x 10(5) vs 0.60 x 10(5), t = 5.92, P<0.01). Exogenous p53 protein also up-regulated p21 promoter driving luciferase expression, comparing to the control group (0.47 x 10(5)), the relative luciferase activity increased (5.63 x 10(5)) obviously (t = 10.12, P<0.01). HCV NS5A protein inhibited both endogenous and exogenous p53 transactivity on p21 promoter in a dose-dependent manner (F > or = 20.71, P<0.01). In the experiment of EMSA, p53 could bind to its specific DNA sequence, but when co-transfected with HCV NS5A expressing vector, the p53 binding affinity to its DNA decreased.

CONCLUSIONHCV NS5A can inhibit p53 protein transactivity on p21 promoter through its inhibiting of p53 binding ability to the specific DNA sequence.

Hepacivirus ; genetics ; Humans ; Promoter Regions, Genetic ; Transcriptional Activation ; drug effects ; Tumor Suppressor Protein p53 ; drug effects ; genetics ; metabolism ; physiology ; Viral Core Proteins ; genetics ; Viral Nonstructural Proteins ; genetics ; pharmacology

OBJECTIVETo investigate the effect of ginsenosides of ginseng stem and leaf (GSL) on the transcription activity of glucocorticoid receptor (GR).

METHODSHL7702 cells were transiently cotransfected by GR luciferase reporter plasmid pGRE-tk-Luc and inner referential gene pRL-SV40 plasmid, and the effects of dexamethasone (Dex) and GSL on the reporter gene expression were detected by dual-luciferase reporter assay.

RESULTSThe reporter gene expression Dex-induced in HL7702 was dose- and time-dependent, it could be multiplied to 93 times in maximum, and could be blocked by the GR antagonist RU486. GSL could not induce the expression of reporter gene but could elevate the induction of Dex for 61.4%.

CONCLUSIONGSL could enhance the inducing effect of Dex on transcription activity of GR in vitro.

Cell Line ; Dexamethasone ; pharmacology ; Gene Expression Regulation ; Genes, Reporter ; Ginsenosides ; isolation & purification ; pharmacology ; Humans ; Liver ; cytology ; Mifepristone ; pharmacology ; Panax ; chemistry ; Plant Leaves ; chemistry ; Plant Stems ; chemistry ; Receptors, Glucocorticoid ; drug effects ; physiology ; Transcriptional Activation ; drug effects ; Transfection

Glucocorticoid receptor (GR) is identified as a member of nuclear receptor family. To exert its biological action, the ligand bound GR is translocated from the cytoplasm into the nucleus by regulating transcriptional signals of related genes. In clinical practice, the effects of glucocorticoid are often mediated by GR signaling pathways. An increasing number of studies have indicated that GR signaling pathways play an essential role in the proliferation, invasion and prognosis of bladder cancer. Meanwhile, the new-generation selective GR activator improves its anti-tumor effects, and at the same time reduces the adverse reactions of hormones, which probably raises the prospect for the treatment of bladder cancer.
Animals ; Antineoplastic Agents ; pharmacology ; Cell Nucleus ; genetics ; Humans ; Prognosis ; Protein Transport ; genetics ; Receptors, Glucocorticoid ; agonists ; physiology ; Signal Transduction ; genetics ; Transcriptional Activation ; drug effects ; physiology ; Urinary Bladder Neoplasms ; genetics ; physiopathology

BACKGROUNDBone morphogenetic protein-6 (BMP-6) is closely correlated with tumor differentiation and skeletal metastasis. Estrogen is considered as a stimulant for the initiation and promotion of breast cancer. Previous studies demonstrated that 17beta-estadiol (E2) can selectively increase the expression of BMP-6. This experiment is designed to detect the molecular mechanism of estrogen activating BMP-6 gene transcription in human estrogen receptor positive (ER+) breast cancer cell line MCF-7.

METHODSAfter the treatment of MCF-7 cells with E2 at different concentrations (10(-11) mol/L, 10(-9) mol/L, 10(-7) mol/L), the BMP-6 expression level was examined through real-time polymerase chain reaction. Through restriction enzyme digestion, human BMP-6 1.2 kb long promoter, BMP-6 0.7 kb long promoter was cloned into pGL-3 basic vector; after the treatment with 10(-7) mol/L E2, luciferase activities of the two promoters were detected. Site-directed mutagenesis was performed to obtain the mutant forms of estrogen response element half-site (1/2 ERE) element and Sp1 sites in the BMP-6 promoter, the activities of these mutant form promoters were detected following the methods mentioned above. Chromatin immunoprecipitation (ChIP) assay was also used to confirm the binding of estrogen receptor alpha (ERalpha) on BMP-6 promoter in the presence of E2.

RESULTSE2 dose dependently increased BMP-6 mRNA expression in human ER+ breast cancer cell line MCF-7. At a dose of 10(-7) mol/L E2, human BMP-6 1.2 kb promoter activity was increased by 90% compared with the control group treated with ethanol (P < 0.05). Both the 1/2 ERE response element mutant form and the Sp1 site mutant form of the BMP-6 promoter abolished the activation of the BMP-6 promoter's response to E2. Through ChIP assay, the binding of ERalpha on 1/2 ERE response element in BMP-6 promoter was further validated.

CONCLUSIONEstrogen induces BMP-6 expression in human ER+ breast cancer cell line MCF-7 through its receptor ERalpha binding on 1/2 ERE element in the BMP-6 promoter.

Bone Morphogenetic Protein 6 ; Bone Morphogenetic Proteins ; genetics ; Breast Neoplasms ; genetics ; Cell Line, Tumor ; Dose-Response Relationship, Drug ; Estradiol ; pharmacology ; Estrogen Receptor alpha ; physiology ; Female ; Humans ; Parathyroid Hormone-Related Protein ; secretion ; Promoter Regions, Genetic ; Transcriptional Activation ; drug effects

Intravenous anesthetics are known to cause amnesia, but the underlying molecular mechanisms remain elusive. To identify a possible molecular mechanism, we recently turned our attention to a key intracellular signaling pathway organized by a family of mitogen-activated protein kinases (MAPKs). As a prominent synapse-to-nucleus superhighway, MAPKs couple surface glutamate receptors to nuclear transcriptional events essential for the development and/or maintenance of different forms of synaptic plasticity (long-term potentiation and long-term depression) and memory formation. To define the role of MAPK-dependent transcription in the amnesic property of anesthetics, we conducted a series of studies to examine the effect of a prototype intravenous anesthetic propofol on the MAPK response to N-methyl-D-aspartate receptor (NMDAR) stimulation in hippocampal neurons. Our results suggest that propofol possesses the ability to inhibit NMDAR-mediated activation of a classic subclass of MAPKs, extracellular signal-regulated protein kinase 1/2 (ERK1/2). Concurrent inhibition of transcriptional activity also occurs as a result of inhibited responses of ERK1/2 to NMDA. These findings provide first evidence for an inhibitory modulation of the NMDAR-MAPK pathway by an intravenous anesthetic and introduce a new avenue to elucidate a transcription-dependent mechanism processing the amnesic effect of anesthetics.
Amnesia ; chemically induced ; enzymology ; Anesthetics, Intravenous ; pharmacology ; Animals ; Cells, Cultured ; Extracellular Signal-Regulated MAP Kinases ; drug effects ; metabolism ; Hippocampus ; cytology ; drug effects ; enzymology ; Long-Term Potentiation ; drug effects ; physiology ; Memory ; drug effects ; physiology ; Mitogen-Activated Protein Kinase 1 ; drug effects ; Mitogen-Activated Protein Kinase 3 ; drug effects ; Neurons ; drug effects ; enzymology ; Propofol ; pharmacology ; Rats ; Receptors, N-Methyl-D-Aspartate ; metabolism ; Signal Transduction ; drug effects ; physiology ; Transcriptional Activation ; drug effects

Echinomycin is a small-molecule inhibitor of hypoxia-inducible factor-1 DNA-binding activity, which plays a crucial role in ovarian ovulation in mammalians. The present study was designed to test the hypothesis that hypoxia-inducible factor (HIF)-1alpha-mediated endothelin (ET)-2 expressions contributed to ovarian ovulation in response to human chorionic gonadotropin (hCG) during gonadotropin-induced superuvulation. By real-time RT-PCR analysis, ET-2 mRNA level was found to significantly decrease in the ovaries after echinomycin treatment, while HIF-1alpha mRNA and protein expression was not obviously changed. Further analysis also showed that these changes of ET-2 mRNA were consistent with HIF-1 activity in the ovaires, which is similar with HIF-1alpha and ET-2 expression in the granulosa cells with gonadotropin and echinomycin treatments. The results of HIF-1alpha and ET-2 expression in the granulosa cells transfected with cis-element oligodeoxynucleotide (dsODN) under gonadotropin treatment further indicated HIF-1alpha directly mediated the transcriptional activation of ET-2 during gonadotropin-induced superuvulation. Taken together, these results demonstrated that HIF-1alpha-mediated ET-2 transcriptional activation is one of the important mechanisms regulating gonadotropin-induced mammalian ovulatory precess in vivo.
Animals ; Cells, Cultured ; Chorionic Gonadotropin/*pharmacology ; Echinomycin/*pharmacology ; Endothelin-2/genetics/*metabolism ; Female ; Gonadotropins, Equine/*pharmacology ; Granulosa Cells/drug effects/metabolism ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit/*antagonists & inhibitors/genetics/metabolism/physiology ; Oligonucleotides/genetics ; Ovary/cytology/drug effects/physiology ; Rats ; Rats, Sprague-Dawley ; Superovulation/*drug effects ; Transcriptional Activation

Chemokines and chemokine receptors play a role in migration of circulating leukocytes to the region of inflammation. Human LZIP is an uncharacterized transcription factor and is known to participate in leukotactin (Lkn)-1/CCL15-induced cell migration. We investigated the role of human LZIP in expression of CC chemokine receptors (CCRs) and its involvement in monocyte migration. RNase protection analysis showed that LZIP increased mRNA expression of CCR2 and CCR1 in THP-1 cells. Surface expressions of both CCR2 and CCR1 were also increased by LZIP. Results from an electrophoretic mobility shift assay showed that LZIP binds to the C/EBP element in the CCR2 promoter. LZIP also enhanced the chemotactic activities of monocyte chemoattractant protein-1/CCL2 and Lkn-1. These results suggest that LZIP regulates expression of chemokine receptors that are involved in monocyte migration.
Atherosclerosis/drug therapy/etiology ; CCAAT-Enhancer-Binding Proteins/genetics/immunology/*metabolism ; Cell Line, Tumor ; Cell Movement/drug effects/*physiology ; Chemokine CCL2/*pharmacology ; Chemokines, CC/pharmacology ; Cyclic AMP Response Element-Binding ; Humans ; Macrophage Inflammatory Proteins/pharmacology ; Monocytes/drug effects/metabolism ; Promoter Regions, Genetic ; Protein Binding ; RNA, Messenger/analysis ; Receptors, CCR1/biosynthesis/genetics ; Receptors, CCR2/*biosynthesis/genetics ; Transcriptional Activation/drug effects ; Transfection ; Transgenes

The nuclear receptors, steroid and xenobiotic receptor (SXR) and constitutive androstane receptor (CAR) play important functions in mediating lipid and drug metabolism in the liver. The present study demonstrates modulatory actions of estrogen in transactivations of SXR-mediated liver X receptor response element (LXRE) and CAR-mediated phenobarbital response element (PBRU). When human estrogen receptor (hERalpha) and SXR were exogenously expressed, treatment with either rifampicin or corticosterone promoted significantly the SXR-mediated transactivation of LXRE reporter gene in HepG2. However, combined treatment with estrogen plus either rifampicin or corticosterone resulted in less than 50% of the mean values of the transactivation by rifampicin or corticosterone alone. Thus, it is suggested that estrogen may repress the SXR-mediated transactivation of LXRE via functional cross-talk between ER and SXR. The CAR-mediated transactivation of PBRU was stimulated by hERalpha in the absence of estrogen. However, the potentiation by CAR agonist, TCPOBOP, was significantly repressed by moxestrol in the presence of ER. Thus, ER may play both stimulatory and inhibitory roles in modulating CAR-mediated transactivation of PBRU depending on the presence of their ligands. In summary, this study demonstrates that estrogen modulates transcriptional activity of SXR and CAR in mediating transactivation of LXRE and PBRU, respectively, of the nuclear receptor target genes through functional cross-talk between ER and the corresponding nuclear receptors.
Corticosterone/pharmacology ; Estrogens/*metabolism ; Ethinyl Estradiol/analogs & derivatives/pharmacology ; Hep G2 Cells ; Humans ; Liver/*metabolism ; Orphan Nuclear Receptors/metabolism ; Phenobarbital/metabolism ; Pyridines/pharmacology ; Receptor Cross-Talk ; Receptors, Cytoplasmic and Nuclear/agonists/*metabolism ; Receptors, Steroid/*metabolism ; Response Elements ; Rifampin/pharmacology ; Transcriptional Activation/*drug effects/physiology

OBJECTIVETo study the specific expression of the antisense RNA against hepatitis B virus X (HBX) gene in hepatoblastoma cell line and its anti -HBV activity.

METHODSHBX gene (nt.1370-1827) was amplified by PCR, then cloned into EB virus vector pEBAF which contained human alpha-fetoprotein promoter and enhancer. After transfected into 2.2.15 hepatoma cells and ECV304 human endothelial cells by lipofectin, northern blot, ELISA and real-time qualitative PCR were carried out to assay the expression of HBX mRNA, HBV antigens and HBV DNA level, respectively.

RESULTSThe HBX antisense RNA expression vector pEBAF-as-HBX which could be expressed specifically in 2.2.15 hepatoblastoma cells was successfully constructed. Both HBV DNA level and the expressions of hepatitis B virus surface antigen (HBsAg) and e antigen (HBeAg) in 2.2.15 hepatoblastoma cells were inhibited by pEBAF-as-HBX. Compared with those in sense control (pEBAF-s-HBX), the inhibitory rates of HBsAg, HBeAg, and HBV DNA were 37.9%, 36.8%, and 25%, respectively.

CONCLUSIONSThe pEBAF-as-HBX expression vector may lead to targeted-expression of HBX antisense RNA in hepatoma cells and shows great inhibition effect on HBV.

Animals ; Carcinoma, Hepatocellular ; genetics ; pathology ; virology ; Cell Line, Tumor ; DNA Replication ; Enhancer Elements, Genetic ; genetics ; Gene Expression Regulation, Viral ; drug effects ; Genetic Therapy ; methods ; Hepatitis B virus ; genetics ; physiology ; Humans ; Liver Neoplasms ; genetics ; pathology ; virology ; Promoter Regions, Genetic ; genetics ; RNA, Antisense ; pharmacology ; Trans-Activators ; biosynthesis ; genetics ; Transcriptional Activation ; Transfection ; alpha-Fetoproteins ; genetics

Lysophosphatidic acid (LPA) is a bioactive phospholipids and involves in various cellular events, including tumor cell migration. In the present study, we investigated LPA receptor and its transactivation to EGFR for cyclooxygenase-2 (COX-2) expression and cell migration in CAOV-3 ovarian cancer cells. LPA induced COX-2 expression in a dose-dependent manner, and pretreatment of the cells with pharmacological inhibitors of Gi (pertussis toxin), Src (PP2), EGF receptor (EGFR) (AG1478), ERK (PD98059) significantly inhibited LPA- induced COX-2 expression. Consistent to these results, transfection of the cells with selective Src siRNA attenuated COX-2 expression by LPA. LPA stimulated CAOV-3 cell migration that was abrogated by pharmacological inhibitors and antibody of EP2. Higher expression of LPA2 mRNA was observed in CAOV-3 cells, and transfection of the cells with a selective LPA2 siRNA significantly inhibited LPA-induced activation of EGFR and ERK, as well as COX-2 expression. Importantly, LPA2 siRNA also blocked LPA-induced ovarian cancer cell migration. Collectively, our results clearly show the significance of LPA2 and Gi/Src pathway for LPA-induced COX-2 expression and cell migration that could be a promising drug target for ovarian cancer cell metastasis.
Butadienes/pharmacology ; Cell Line, Tumor ; Cell Movement/drug effects/*physiology ; Cyclooxygenase 2/*biosynthesis ; Extracellular Signal-Regulated MAP Kinases/antagonists & inhibitors/metabolism ; Female ; Flavonoids/pharmacology ; GTP-Binding Protein alpha Subunits, Gi-Go/antagonists & inhibitors/*metabolism ; Humans ; Lysophospholipids/pharmacology ; Nitriles/pharmacology ; Ovarian Neoplasms/metabolism/*pathology ; Pertussis Toxin/pharmacology ; Protein-Tyrosine Kinases/antagonists & inhibitors/*metabolism ; Proto-Oncogene Proteins/antagonists & inhibitors/*metabolism ; Pyrimidines/pharmacology ; Receptor, Epidermal Growth Factor/antagonists & inhibitors/metabolism ; Receptors, Lysophosphatidic Acid/*metabolism ; Receptors, Prostaglandin E/metabolism ; Signal Transduction ; Transcriptional Activation ; Tyrphostins/pharmacology