Table 3

Comparison of folic acid binding to cells grown with 2.2 μm folic acid or 25 nm 5-CHO-THF

Folic acid binding was assessed in cells grown in complete RPMI 1640 containing 2.2 μm folic acid or folate free-RPMI 1640 supplemented with 25 nm 5-CHO-THF. The LL1 cell line, which was adapted for the growth in 0.4 nm 5-CHO-THF and which stably overexpresses folate receptor α, was used as positive control (48). The folic acid binding capacity in LL1 line was 1300 ± 180 pmol/g dry weight. The data are the mean ± SE from three separate experiments.

Cell lineFolic acid bound to cells grown in 2.2 μm folic acid (pmol/g dry weight)Folic acid bound to cells grown in 25 nm 5-CHO-THF (pmol/g dry weight)Fold change, 5-CHO-THF/ folic acid
L12105.8 ± 0.411 ± 11.9
L1210-G1a1.9 ± 0.23.6 ± 0.61.9
MTXTA8.5 ± 1.314 ± 21.6