OBJECTIVETo detect the effect of interferon-α2a(IFN-α2a) on thymidine phosphorylase(TP) mRNA expression levels and the anticancer activity of 5-fluorouracil(5-FU) and 5'-deoxy-fluorouridine(5'-DFUR) in human colon carcinoma cell lines LOVO and SW480.

METHODSTwo human colon cancer cell lines LOVO and SW480 were cultured and treated with IFN-α2a at a series of dosage, and fluorescence quantitative PCR was carried out to detect the TP mRNA expression levels in these 2 cell lines. Then MTT assay and software Templet were used to determine the change of 50% inhibition concentration of 5-FU or 5'-DFUR combined with IFN-α2a on the two cell lines.

RESULTSThe TP mRNA expressions were up-regulated significantly by IFN-α2a at the doses of 500 U/ml and 5000 U/ml in LOVO(P<0.01). Compared with untreated cells(IFN-α2a 0 U/ml), no significance was found for TP mRNA expression levels in LOVO and SW480 treated by IFN-α2a at the dose of 50 U/ml (P>0.05). There was no significant difference for TP mRNA expression in SW480 between the dose of 0 U/ml and 500 U/ml of IFN-α2a(P>0.05), while a significant increace was detected at the dose of 5000 U/ml (P<0.01). No significant difference was found for the IC50 values after treatment of 5-FU combined with IFN-α2a (20 U/ml) on LOVO and SW480 compared with 5-FU alone, while the IC50 values after treatment of 5'-DFUR combined with IFN-α2a decreased significantly compared with 5'-DFUR alone(P<0.05).

CONCLUSIONThere is no direct inhibition effect of IFN-α2a on LOVO and SW480 in vitro, while it can up-regulate TP mRNA expression levels both in LOVO and SW480, and enhance the anticancer effect of 5'-DFUR on these 2 cell lines.