[Hyperthermia enhanced the killing effect of 5-fluorocytosine on human colon cancer cell line transfected with cytosine deaminase gene].
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.
Li
Jin-mao
JM
Department of General Surgery, Tangdu Hospital, The Fourth Military Medical University, Xi'an 710038, China. LJMLYY@163.com
Li
Cheng-jin
CJ
Lai
Da-nian
DN
Wang
Xiao-jun
XJ
He
Xian-li
XL
Bao
Guo-qiang
GQ
Wu
Tao
T
Yin
Ji-kai
JK
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
D005437:Flucytosine; D043525:Cytosine Deaminase