[Experimental studies on the treatment of colon cancer by cytosine deaminase gene and 5-fluorocytosine].

OBJECTIVE

To investigate the effect of cytosine deaminase (CD) gene plus 5-fluorocytosine (5-Fc) on the growth of human colon cancer xenograftin nude mice.

METHODS

Retroviral vector expressing CD gene was transfected into human colon cancer SW1116 cells. Expression of the transfected CD gene in SW1116 (SWCD(2)) was confirmed by RT-PCR. The cytotoxicity of 5-Fc on SW1116 was determined by MTT assay in vitro. In vivo, the CD gene expression vector was injected intratumorally and 5-Fc was given by ip injections.

RESULTS

In vitro, SWCD(2) cells were killed by 5-Fc with an IC(50) of 66 micromol/L while the nontrasfected SW1116 cells needed an IC(50) of 16 000 micromol/L to be killed. The growth of SWCD(2) xenografts was significantly inhibited by systemic administration of 5-Fc.

CONCLUSION

CD gene/5-Fc system is a potential gene therapy strategy for human colon cancer.