Inhibitory Effects, Accumulation of Polyglutamates and Kinetic Parameters of FPGS in ALL and AML Cell Lines With MTX, Tomudex, and 1843U89 as Substrates
| . | IC50 . | Long Chain Polyglutamates . | Long Chain Polyglutamates as % of Total Polyglutamates . | Km . | Vmax . |
|---|---|---|---|---|---|
| . | (nmol/L) . | (pmol/107 cells) . | . | (μmol/L) . | (pmol/mg/h) . |
| MTX | |||||
| CCRF-CEM | 171 ± 15 | 59.6 ± 2.6 | 85 | 44 ± 0.2 | 1,575 ± 152 |
| MOLT-3 | 50 ± 10 | 35.2 ± 3.3 | 80 | 23 ± 4.5 | 1,230 ± 41 |
| K562 | 740 ± 14 | 14.5 ± 2.3 | 28 | 92 ± 9 | 1,473 ± 13 |
| HL-60 | 103 ± 23 | 53.7 ± 8.6 | 73 | 89 ± 4.6 | 5,067 ± 1,167 |
| Tomudex | |||||
| CCRF-CEM | 15 ± 0.5 | 7.43 ± 2.2 | 90 | 0.5 ± 0.12 | 1,566 ± 350 |
| MOLT-3 | 12 ± 0.5 | 5.78 ± 0.4 | 83 | 1.2 ± 0.2 | 1,574 ± 89 |
| K562 | 11 ± 0.5 | 7.23 ± 1.2 | 88 | 0.6 ± 0.2 | 1,358 ± 365 |
| HL-60 | 8 ± 1 | 5.43 ± 0.4 | 85 | 1.6 ± 0.5 | 2,400 ± 575 |
| 1843U89 | |||||
| CCRF-CEM | 4 ± 1 | 102 ± 7 | 97 | 2.4 ± 0.9 | 3,274 ± 1,214 |
| MOLT-3 | 4 ± 0.6 | 41 ± 6 | 87 | 6.2 ± 0.3 | 3,320 ± 170 |
| K562 | 10 ± 4 | 59 ± 6 | 97 | 1.2 ± 0.3 | 1,423 ± 180 |
| HL-60 | 3 ± 1 | 56 ± 17 | 92 | 4.5 ± 0.7 | 4,200 ± 260 |
| . | IC50 . | Long Chain Polyglutamates . | Long Chain Polyglutamates as % of Total Polyglutamates . | Km . | Vmax . |
|---|---|---|---|---|---|
| . | (nmol/L) . | (pmol/107 cells) . | . | (μmol/L) . | (pmol/mg/h) . |
| MTX | |||||
| CCRF-CEM | 171 ± 15 | 59.6 ± 2.6 | 85 | 44 ± 0.2 | 1,575 ± 152 |
| MOLT-3 | 50 ± 10 | 35.2 ± 3.3 | 80 | 23 ± 4.5 | 1,230 ± 41 |
| K562 | 740 ± 14 | 14.5 ± 2.3 | 28 | 92 ± 9 | 1,473 ± 13 |
| HL-60 | 103 ± 23 | 53.7 ± 8.6 | 73 | 89 ± 4.6 | 5,067 ± 1,167 |
| Tomudex | |||||
| CCRF-CEM | 15 ± 0.5 | 7.43 ± 2.2 | 90 | 0.5 ± 0.12 | 1,566 ± 350 |
| MOLT-3 | 12 ± 0.5 | 5.78 ± 0.4 | 83 | 1.2 ± 0.2 | 1,574 ± 89 |
| K562 | 11 ± 0.5 | 7.23 ± 1.2 | 88 | 0.6 ± 0.2 | 1,358 ± 365 |
| HL-60 | 8 ± 1 | 5.43 ± 0.4 | 85 | 1.6 ± 0.5 | 2,400 ± 575 |
| 1843U89 | |||||
| CCRF-CEM | 4 ± 1 | 102 ± 7 | 97 | 2.4 ± 0.9 | 3,274 ± 1,214 |
| MOLT-3 | 4 ± 0.6 | 41 ± 6 | 87 | 6.2 ± 0.3 | 3,320 ± 170 |
| K562 | 10 ± 4 | 59 ± 6 | 97 | 1.2 ± 0.3 | 1,423 ± 180 |
| HL-60 | 3 ± 1 | 56 ± 17 | 92 | 4.5 ± 0.7 | 4,200 ± 260 |
Cell lines were exposed to different concentrations of these drugs and cell viability measured as described in Materials and Methods. Polyglutamates formation was measured after a 24-hour exposure to radiolabeled drugs as also described in Materials and Methods. Cells extracts were prepared as described in Materials and Methods. Substrates at different concentrations were used to measure enzyme activity and to determine Km and Vmax values. The results are the average of at least 3 or more experiments with standard deviations provided.