title: Transcription regulation of rat glutathione S-transferase Ya subunit gene expression by chemopreventive agents.
abstract: OBJECTIVE
  To study the transcription regulation of rat glutathione S-transferase Ya (rGSTya) subunit gene expression by chemopreventive agents.
  
  
  METHODS
  The effects of chemopreventive agents; tamoxifen, genistein, oltipraz, indole-3-carbinol, and various isothiocyanates-sulforaphane, PMITC, PEITC, PBITC, and PPITC, on the transcriptional activation of rGSTya were investigated in cell culture. These were accomplished with a stable human hepatoma Hep G2 cell line transfected with a 1.6 kilobase (kb) 5'-flanking region of the rGSTya fused with the chloramphenicol acetyltransferase (CAT) reporter gene. Concentration-effect relationship and the kinetics of gene activation following treatments of the cells with different chemopreventive agents were carried out by quantitating CAT reporter protein using ELISA. Northern blot analysis of total RNA on the expression of CAT mRNA as well as potential transcription factors such as c-Jun, c-Fos, and LFR-1 were performed.
  
  
  RESULTS
  Treatment of the cells with increasing concentrations of different chemopreventive agents resulted in corresponding increases in the gene expression of CAT reporter protein. Kinetically, induction of CAT protein was seen as early as 3 hr and peaked at about 20 hr. Northern blot analysis revealed an increase in CAT mRNA transcripts and these mRNA inductions in general were in agreement with those quantitated by the production of CAT reporter protein. Induction of the transcription factor, c-Jun mRNA was observed with sulforaphane.
  
  
  CONCLUSIONS
  These results show that different chemopreventive agents transcriptionally activate rGSTya CAT in a time and dose-dependent fashion.
authors.affiliation: Divison of Clinical Pharmacology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.
authors.forename: P
authors.initials: P
authors.lastname: Fei
authors.forename: G A
authors.initials: GA
authors.lastname: Matwyshyn
authors.forename: T H
authors.initials: TH
authors.lastname: Rushmore
authors.forename: A N
authors.initials: AN
authors.lastname: Kong
mesh_terms: D016588:Anticarcinogenic Agents / Q000494:pharmacology*; D015152:Blotting, Northern; D015500:Chloramphenicol O-Acetyltransferase / Q000096:biosynthesis / Q000235:genetics; D004305:Dose-Response Relationship, Drug; D004790:Enzyme Induction; D005786:Gene Expression Regulation / Q000187:drug effects*; D017930:Genes, Reporter / Q000235:genetics; D005982:Glutathione Transferase / Q000096:biosynthesis / Q000187:drug effects* / Q000235:genetics; D006801:Humans; D017879:Isothiocyanates; D008099:Liver / Q000201:enzymology; D011719:Pyrazines / Q000494:pharmacology; D013454:Sulfoxides; D013629:Tamoxifen / Q000494:pharmacology; D013861:Thiocyanates / Q000494:pharmacology; D013871:Thiones; D013876:Thiophenes; D013997:Time Factors; D014158:Transcription, Genetic / Q000187:drug effects*; D015533:Transcriptional Activation; D014407:Tumor Cells, Cultured / Q000201:enzymology
chemical_list: D016588:Anticarcinogenic Agents; D017879:Isothiocyanates; D011719:Pyrazines; D013454:Sulfoxides; D013861:Thiocyanates; D013871:Thiones; D013876:Thiophenes; D013629:Tamoxifen; C026209:oltipraz; D015500:Chloramphenicol O-Acetyltransferase; D005982:Glutathione Transferase; C016766:sulforaphane