Figure 2. MMR-deficient cells that are refractory to 5-FU are sensitive to FTD.

Clonogenic assay of HCT116 (hMLH1(−)) and 5-FU resistant HCT116 (hMLH1(−) [5-FU(R)]). A total of 1 × 10³ cells per 100-mm dish (A, B) or 1 × 10⁴ cells per 100-mm dish (C) were plated in media containing 0, 2.5, or 5 μM of 5-FU and were allowed to form colonies over 10 days. Same procedure as before with FTD (0, 0.5, 1 or 2.5 μM) (D, E, F). Each experiment was performed in triplicate, and the experiment was replicated three independent times. Data were expressed as the mean±SE. ^*P < 0.05.