TABLE 1
Chemosensitivity to Me-Lex of MR-proficient and MR-deficient leukemia cell lines determined by colony forming ability
Cells were incubated with graded concentrations of Me-Lex for 4 h and then plated at 1 cell/well using a 96-well plate for each drug concentration tested. After 10 days, plates were analyzed for colony forming ability (Tentori et al., 2003). Cell line chemosensitivity to Me-Lex was evaluated in terms of IC50, i.e., the concentration of the drug expressed in micromolar, capable of inhibiting colony-forming ability by 50%. The IC50 was calculated on the regression line in which the number of colonies was plotted versus the drug concentrations. Each value represents the mean of three independent experiments ± S.E.