OBJECTIVESTo study the change of ability to transform from 5'-deoxy-fluorouracil monophosphate (5'-DFUR) to fluorouracil (5-FU) in human colon cancer cell lines SW480 and LOVO which transfected with thymidine phosphorylase (TP) gene. And to discuss the anti-cancer activity of 5'-DFUR to SW480 and LOVO cells.

METHODSTP cDNA were transfected into human colorectal cancer cell lines SW480 and LOVO with the lentiviral vector, pLenti6.3_MCS_IRES2-EGFP. The transfection efficiency was analyzed by flow cytometer, the mRNA expression of TP was detected by RT-PCR, and the TP protein expression was detected by Western blot, and the volumes of 5-FU converted from 5'-DFUR both in 2 cells and medium were detected by high performance liquid chromatography (HPLC). The 50% inhibitory concentration (IC50) of 5'-DFUR on these 2 colon cancer cell lines both wild type and TP-transfected cells were evaluated by MTT assay.

RESULTSThe colorectal cancer cell lines SW480 and LOVO transfected with human TP cDNA were monitored 5 generations, and the transfections efficiency rate wea about 95%. Compared with wild type cell SW480 and LOVO, the RQ values of mRNA expression of SW480-TP and LOVO-TP were (695 ± 171) folds (t = -7.00, P = 0.002) and (282 ± 87) folds (t = -5.61, P = 0.030), respectively. Also TP protein expression in SW480-TP and LOVO-TP were higher than their parent cells shown by Western blot. The volume of 5-FU converted from 5'-DFUR in the medium cultured SW480-TP and LOVO-TP were increased compared with their parent cells, respectively (t = 19.406-66.921, P < 0.01), whereas few of 5-FU was detected both in wild, and TP-transfected cells. After transfected with TP cDNA, the IC50 of 5'-DFUR on SW480-TP and LOVO-TP were (587 ± 17) µmol/L and (1088 ± 89) µmol/L respectively, and there were significantly less than their parent cells (t = -32.59 and -8.52, P < 0.01).

CONCLUSIONSThe stabilized transfections of SW480 and LOVO with higher TP expression could be built with lentiviral vector. Transfected TP cDNA into SW480 and LOVO, could improve the expression both of TP mRNA and TP protein, increase the volume of 5-FU converted from 5'-DFUR in medium, and result in an enhancement of anticancer effect on these 2 cells.