title: β-catenin accumulation in nuclei of hepatocellular carcinoma cells up-regulates glutathione-s-transferase M3 mRNA.
abstract: OBJECTIVE
  To identify the differentially over-expressed genes associated with β-catenin accumulation in nuclei of hepatocellular carcinoma (HCC) cells.
  
  
  METHODS
  Differentially expressed genes were identified in radiation-induced B6C3 F1 mouse HCC cells by mRNA differential display, Northern blot and RT-PCR, respectively. Total glutathione-s-transferase (GST) activity was measured by GST activity assay and β-catenin localization was detected with immunostaining in radiation-induced mouse HCC cells and in HepG2 cell lines.
  
  
  RESULTS
  Two up-regulated genes, glutamine synthetase and glutathione-s-transferase M3 (GSTM3), were identified in radiation-induced mouse HCC cells. Influence of β-catenin accumulation in nuclei of HCC cells on up-regulation of GSTM3 mRNA was investigated. The nearby upstream domain of GSTM3 contained the β-catenin/Tcf-Lef consensus binding site sequences [5'-(A/T)(A/T) CAAAG-3'], and the total GST activity ratio was considerably higher in B6C3F1 mouse HCC cells with β-catenin accumulation in nuclei of HCC cells than in those without β-catenin accumulation (0.353 ± 0.117 vs. 0.071 ± 0.064, P < 0.001). The TWS119 (a distinct GSK-3β inhibitor)-induced total GST activity was significantly higher in HepG2 cells with β-catenin accumulation than in those without β-catenin accumulation in nuclei of HCC cells. Additionally, the GSTM3 mRNA level was significantly higher at 24 h than at 12 h in TWS119-treated HepG2 cells.
  
  
  CONCLUSIONS
  β-catenin accumulation increases GST activity in nuclei of HCC cells, and GSTM3 may be a novel target gene of the β-catenin/Tcf-Lef complex.
authors.affiliation: Department of Pharmacology, College of Pharmacy, South-Central University for Nationalities, No. 708, Minyuan Road, Wuhan 430074, Hubei Province, China.
authors.forename: Yu-Sang
authors.initials: YS
authors.lastname: Li
authors.forename: Min
authors.initials: M
authors.lastname: Liu
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Nakata
authors.forename: He-Bin
authors.initials: HB
authors.lastname: Tang
mesh_terms: D000818:Animals; D006528:Carcinoma, Hepatocellular / Q000201:enzymology* / Q000235:genetics* / Q000473:pathology; D002467:Cell Nucleus / Q000378:metabolism; D005982:Glutathione Transferase / Q000235:genetics* / Q000378:metabolism; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D008113:Liver Neoplasms / Q000201:enzymology* / Q000235:genetics* / Q000473:pathology; D051379:Mice; D012333:RNA, Messenger / Q000378:metabolism*; D015854:Up-Regulation; D051176:beta Catenin / Q000378:metabolism*
chemical_list: D007527:Isoenzymes; D012333:RNA, Messenger; D051176:beta Catenin; D005982:Glutathione Transferase; C416969:glutathione transferase M3-3