Chemosensitivities of CEM, CEM-ARAC/hENT2, CEM-ARAC/hCNT1, CEM-ARAC/hCNT2, and CEM-ARAC cells to BR and TR Actively proliferating cells were exposed to graded concentrations of BR or TR in 96-well plates for 4 and 48 h as described under Materials and Methods. In protection experiments, CEM cells were treated with 1 μM NBMPR 1 h before the addition of BR or TR in the presence of 1 μM NBMPR. IC50 values were obtained from the MTS-cytotoxicity relationships and are means of at least two experiments, each conducted with six replicates. Mean ± S.E. values were determined using GraphPad Prism software version 3.0.
| IC50 | ||||
|---|---|---|---|---|
| BR | TR | |||
| 4 h | 48 h | 4 h | 48 h | |
| μM | ||||
| CEMa | 11 ± 2.9 | 1.7 ± 0.28 | >500 | 78 ± 2.5 |
| + 1 μM NBMPR | 46 ± 5.7 | 6.0 ± 0.75 | >500 | 130 ± 6.2 |
| CEM-ARAC/hENT2 | 9 ± 3.5 | 2.5 ± 0.31 | >500 | 110 ± 5.1 |
| CEM-ARAC/hCNT1 | 42 ± 9.2 | 2.8 ± 0.18 | >500 | 130 ± 21 |
| CEM-ARAC/hCNT2 | 108 ± 15 | 6.6 ± 0.4 | >500 | 106 ± 15 |
| CEM-ARACb | 107 ± 17 | 6.5 ± 0.42 | >500 | 110 ± 5 |