OBJECTIVETo establish an exonuclease protection mediated polymerase chain reaction (PCR) assay for the non-radioactive, sensitive detection of the binding of protein and DNA.

METHODSThe 1 pmol/L-10 nmol/L 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) dissolved in dimethyl sulphoxide (DMSO), was added into 100 microl SD rat hepatic cytosol in vitro, which contained different amount of aromatic hydrocarbon receptors (AhR) and relative proteins, and ligand-AhR-DRE complex were formed in addition to 1 fmol/L-100 nmol/L DNAs probes containing the sequence of DRE. With the digestion of Exonuclease III and S1 nuclease, free DNAs were digested to oligonucleotide and binding DNA remained due to protein (AhR) protection and be amplified by PCR. The results of PCRs were shown by loading on 2% agarose electrophoresis. DMSO was used as negative control and blank control was set up.

RESULTSTarget DNA (285 bp) could be observed in the ligand groups, but not in the control group. The minimal amount of receptor was 2.5 fmol/L and the minimal amount of DNA probes was 2 fmol.

CONCLUSIONSExonuclease protection mediated PCR assay should be a good non-radioactive tool to quantify the interaction of protein and DNA with high sensitivity and simplicity.

Animals ; Aryl Hydrocarbon Receptor Nuclear Translocator ; genetics ; metabolism ; Binding, Competitive ; DNA Probes ; genetics ; metabolism ; DNA-Binding Proteins ; genetics ; metabolism ; Exonucleases ; metabolism ; Male ; Polymerase Chain Reaction ; methods ; Rats ; Rats, Sprague-Dawley ; Receptors, Aryl Hydrocarbon ; genetics ; metabolism

OBJECTIVETo investigate the effects of ARNT2 on invasion and migration of HCCLM6 cells.

METHODSFour short hairpin oligos targeting to ARNT2 were s cloned into the pLVTHM vector. Lentiviral vectors shRNA-ARNT2i, pCMV-dR8.74 and pMD2G were cotransfected into 293T cells using Lipofectamine 2000. HCCLM6 was infected with virus supernatant. ARNT2 mRNA and protein expressions were detected using quantitative Real time-PCR and Western blot, respectively. The invasion and migration of HCCLM6 cells were evaluated using wound healing assay and cell invasion assay in vitro. Statistical analysis was performed with SPSS 16.0.

RESULTSThe relative mRNA levels of ARNT2 were 0.154+/-0.024, 0.860+/-0.145, 1.004+/-0.009 in shRNA-ARNT2i virus infected HCCLM6 cells, mock-infected cells and control vector virus infected cells (F = 113.14, P more than 0.01). The expression of ARNT2 at protein level was 16.45+/-1.6, 44.56+/-2.07 in the HCCLM6 cells infected with shRNA-ARNT2i virus and negative control vector virus, respectively (t = 18.58, P less than 0.01). The scrape wound of HCCLM6 cells infected with shRNA-ARNT2i virus healed faster than cells infected with control vector virus or mock-infected cells. The number of cells invading through Matrigel was higher in the HCCLM6 cells infected with shRNA-ARNT2i virus (13.25+/-1.04) than that in mock-infected HCCLM6 cells and the HCCLM6 cells infected with negative control vector virus (6.50+/-2.56, 6.75+/-2.05) (F = 29.645, P less than 0.01).

CONCLUSIONInhibition of ARNT2 gene promotes the invasion and migration of HCCLM6 cells.

Aryl Hydrocarbon Receptor Nuclear Translocator ; genetics ; metabolism ; Basic Helix-Loop-Helix Transcription Factors ; genetics ; metabolism ; Blotting, Western ; Carcinoma, Hepatocellular ; genetics ; metabolism ; pathology ; Cell Line, Tumor ; Cell Movement ; Gene Expression Regulation, Neoplastic ; Genetic Vectors ; genetics ; Humans ; Lentivirus ; genetics ; Liver Neoplasms ; genetics ; metabolism ; pathology ; Neoplasm Invasiveness ; Polymerase Chain Reaction ; methods ; RNA, Messenger ; genetics ; metabolism ; RNA, Small Interfering ; genetics ; Transfection

Hypoxia-inducible factors (HIFs) are transcription factors that activate the transcription of target genes involved in crucial aspects of cancer development. This study investigated the expression of HIFs and their contribution to the regulation of target genes related to angiogenesis and glucose metabolism in gastric cancer. The data showed that HIFs were over-expressed in gastric cancer and that activation of the target genes was observed mainly in the early stages. Moreover, the results of the present study revealed that only HIF-1alpha, but not HIF-2alpha dimerizes with HIF-1beta and then regulates expression of target genes in response to hypoxia. The results of the present study demonstrate that HIF-1alpha and HIF-1beta enhances expression of VEGF and glucose metabolism-related genes in response to hypoxia in gastric cancer. These data offer important information regarding HIF pathways in the development of gastric cancer.
Aryl Hydrocarbon Receptor Nuclear Translocator/*genetics/metabolism ; Basic Helix-Loop-Helix Transcription Factors/*genetics/metabolism ; Cell Line, Tumor ; Gene Expression Regulation, Neoplastic ; Glucose/*metabolism ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit/*genetics/metabolism ; Neovascularization, Pathologic/genetics/metabolism ; Stomach Neoplasms/*genetics/metabolism ; Vascular Endothelial Growth Factor A/*genetics/metabolism