title: [Hyperthermia enhanced the killing effect of 5-fluorocytosine on human colon cancer cell line transfected with cytosine deaminase gene].
abstract: OBJECTIVE
  To investigate whether hyperthermia can enhance the killing effect of 5- fluorocytosine (5- FC) on human colorectal carcinoma cell lines SW480 transfected with carcinoembryonic antigen (CEA) tissue- specific cytosine deaminase (CD) gene in vitro,and study its mechanism.
  
  
  METHODS
  Human colorectal carcinoma cell lines SW480 transfected with G1CEACDNa were cultured. The proliferated colonies were treated with the combined therapy of 5-FC and hyperthermia at a temperature of 43 degrees C for 30 min. After eight days, MTT was used to calculate the cellular survival rate,to analyze the killing effect of 5-FC combined with hyperthermia on SW480 cells transfected with CD gene. Flow cytometry was performed to analyze the cellular cycle and transmission electron microscope was used to observe the morphologic changes of SW480 cells after thermochemotherapy.
  
  
  RESULTS
  Hyperthermia combined with 5-FC had an enhanced killing effect on SW480-CEACD cells than 5-FC alone (P< 0.05, t =2.403, n=9). Flow cytometry revealed that the proportion of S stage cell increased in the group treated with hyperthermia and 5- FC (P< 0.001, t =7.158, n=6). Transmission electron microscope showed apoptosis after thermo- chemotherapy.
  
  
  CONCLUSIONS
  Hyperthermia can improve the anti- tumor effect of 5- FC on human colorectal carcinoma cell lines SW480 transfected with CD gene, and the cells were blocked at S stage of cellular cycle and apoptosis was induced following thermochemotherapy.
authors.affiliation: Department of General Surgery, Tangdu Hospital, The Fourth Military Medical University, Xi'an 710038, China. LJMLYY@163.com
authors.forename: Jin-mao
authors.initials: JM
authors.lastname: Li
authors.forename: Cheng-jin
authors.initials: CJ
authors.lastname: Li
authors.forename: Da-nian
authors.initials: DN
authors.lastname: Lai
authors.forename: Xiao-jun
authors.initials: XJ
authors.lastname: Wang
authors.forename: Xian-li
authors.initials: XL
authors.lastname: He
authors.forename: Guo-qiang
authors.initials: GQ
authors.lastname: Bao
authors.forename: Tao
authors.initials: T
authors.lastname: Wu
authors.forename: Ji-kai
authors.initials: JK
authors.lastname: Yin
mesh_terms: D045744:Cell Line, Tumor; D043525:Cytosine Deaminase / Q000235:genetics*; D005437:Flucytosine / Q000494:pharmacology*; D041722:Genes, Transgenic, Suicide; D015316:Genetic Therapy / Q000379:methods*; D006358:Hot Temperature; D006801:Humans
chemical_list: D005437:Flucytosine; D043525:Cytosine Deaminase