IC50 values (μM) of drug-sensitive human lymphoblastic CCRF-CEM and multidrug-resistant CEM/ADR5000 leukemia cells treated with ancistrobreveines A (12), B (13), C (14), and D (6), 6-O-methylhamateine (4), and ent-dioncophylleine A (10), or with doxorubicin.
| Compound | IC50a [μM] | ||
|---|---|---|---|
| CCRF-CEM | CEM/ADR5000 | Degree of resistanceb | |
| Doxorubicin | 0.017 ± 0.002 | 30.07 ± 11.81 | 1769 |
| 4 | 3.948 ± 1.667 | 5.523 ± 1.756 | 1.40 |
| 5c | 3.501 ± 0.069 | 21.38 ± 1.302 | 6.11 |
| 6 | 24.27 ± 1.398 | 29.51 ± 4.297 | 1.21 |
| 7c | 4.731 ± 0.690 | 7.731 ± 0.992 | 1.63 |
| 8c | 23.34 ± 1.630 | 20.06 ± 2.231 | 0.86 |
| 10 | 26.88 ± 0.285 | 31.41 ± 3.550 | 1.17 |
| 12 | 24.78 ± 3.910 | >100 | — |
| 13 | 39.94 ± 6.864 | 50.64 ± 7.465 | 1.27 |
| 14 | 12.44 ± 1.661 | 12.64 ± 2.290 | 1.02 |
a
The lymphoblastic leukemia cells were treated with different concentrations of 4, 6, 10, and 12–14 or with doxorubicin. Cell viability was assessed by the resazurin assay. Mean values and standard deviation of three independent experiments with each six parallel measurements are shown.
b
The degrees of resistance were calculated by division of the IC50 values of the compounds for CEM/ADR5000 cells by the corresponding IC50 values for CCRF/CEM cells.
c
Values reported earlier, see ref. 21 and 30.