Table 3.

HPLC analysis of intracellular pemetrexed

HCT-15 wild-typePT-1
≥Triglutamate (%)68.0 ± 3.362.5 ± 5.0
Diglutamate (%)10.5 ± 1.012.3 ± 2.3
Monoglutamate (%)21.8 ± 3.925.2 ± 4.6
Total pemetrexed (nmol/g protein)23.2 ± 3.312.6 ± 1.8
  • NOTE: [3H]Pemetrexed polyglutamate derivatives were analyzed after a 2-hour interval of uptake with 0.5 μmol/L of radiolabeled drug as described in Materials and Methods. The results are the average ± SE of three independent experiments. The P value between wild-type and PT1 cells for each category of cell pemetrexed was >0.1.