Activation of tegafur to 5-FU in the presence of ALA / SFC.

<p>(A) Growth inhibition of tegafur was determined using an MTT assay after incubating MKN28 cells with 1.0 mM ALA alone or together with 0.5 mM SFC for 96 h. Data are percent growth rate relative to the drug-free controls. (B) 5-FU formation was determined using HPLC. Cells were incubated for 8 h in a culture medium containing 1.0 mM tegafur, 0.3 mM NADPH, 1.0 mM ALA, and 0.5 mM SFC. Data are expressed as means ± S.D. in four (A) or three (B) independent experiments. Statistical significance of difference is indicated by *p<0.01 determined with Student’s t-test.