title: Improved effects of a double suicide gene system on prostate cancer cells by targeted regulation of prostate-specific membrane antigen promoter and enhancer.
abstract: OBJECTIVE
  To explore the specific killing effect on prostate cancer cells of a dual cytosine deaminase (CD) and uracil phosphoribosyltransferase (UPRT) expression plasmid system controlled by the prostate-specific membrane antigen (PSMA) promoter and enhancer.
  
  
  METHODS
  The CD gene was used to construct the recombinant plasmid prostate-specific membrane antigen(promoter/enhancer)-CD (pPSMA(E/P)-CD). The specific regulatory function of the pPSMA(E/P) promoter was demonstrated by detection of enhanced green fluorescent protein (EGFP) expression in the LNCaP cell line. Survival of cells transfected with different plasmids and treated with 5-fluorocytosine (5-FC) was measured by microculture tetrazolium assay. Cell cycle changes were measured by flow cytometry.
  
  
  RESULTS
  Target-specific expression of PSMA(E/P) was observed in the prostate cancer cell line. Cytotoxicity of 5-FC was greater against LNCaP cells transfected with pPSMA(E/P)-CD and UPRT and pPSMA(E/P)-CD than control groups. Percentages of cells in S phase were 37.5% (LNCaP) and 30.6% (5-FC treatment) in the un-transfected groups, whereas they were 23.9% and 12.4% in the double and single suicide gene groups, respectively.
  
  
  CONCLUSIONS
  Our findings confirm the cytotoxic efficacy of the pPSMA(E/P)-CD + 5-FC and pPSMA(E/P)-CD and UPRT + 5-FC suicide gene systems. The CD and UPRT gene system quickly and directly converted 5-FC into 5-FU, and then into toxic metabolites. The CD and UPRT double suicide gene system was more effective in inducing tumor cell apoptosis with 5-FC than the single suicide gene system. Thus, this construct can specifically target prostate cancer cells and might have a role in gene therapy against prostate cancer.
authors.affiliation: Department of Urology, West China Hospital, Sichuan University, Sichuan, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Zhang
authors.forename: Hao
authors.initials: H
authors.lastname: Zeng
authors.forename: Qiang
authors.initials: Q
authors.lastname: Wei
authors.forename: Yiping
authors.initials: Y
authors.lastname: Lu
authors.forename: Xiang
authors.initials: X
authors.lastname: Li
authors.forename: Jia
authors.initials: J
authors.lastname: Wang
authors.forename: Fujun
authors.initials: F
authors.lastname: Zhao
authors.forename: Hong
authors.initials: H
authors.lastname: Li
mesh_terms: D000954:Antigens, Surface / Q000235:genetics*; D045744:Cell Line, Tumor; D043525:Cytosine Deaminase / Q000235:genetics*; D004742:Enhancer Elements, Genetic; D043425:Glutamate Carboxypeptidase II / Q000235:genetics*; D006801:Humans; D008297:Male; D010430:Pentosyltransferases / Q000235:genetics*; D011401:Promoter Regions, Genetic; D011471:Prostatic Neoplasms / Q000628:therapy*; D052416:Targeted Gene Repair
chemical_list: D000954:Antigens, Surface; D010430:Pentosyltransferases; C023269:uracil phosphoribosyltransferase; C473848:FOLH1 protein, human; D043425:Glutamate Carboxypeptidase II; D043525:Cytosine Deaminase