IC50 (micromolar) values of mitoxantrone cytotoxicity in resistant MCF-7/MX100 cells in the absence or presence of various concentrations of modulators The cytotoxicity of mitoxantrone in resistant MCF-7/MX100 cells was determined in the presence of specified concentrations of test compounds (nicardipine, nifedipine, niguldipine, nitrendipine, Im, and IIb) or the vehicle (0.1% DMSO, control) as described under Materials and Methods. Data are the mean ± S.D. from three independent quadruplicate experiments.
40 μM | 20 μM | 10 μM | 5 μM | 2.5 μM | 1.0 μM | ||
|---|---|---|---|---|---|---|---|
| Nicardipine | 6.29 ± 0.35 | 5.68 ± 0.80 | 10.07 ± 1.16 | 28.7 ± 3.66 | 80.1 ± 7.4 | 166.9 ± 19.0* | |
| Nifedipine | 143.1 ± 17.8* | 147 ± 22.2* | 159.6 ± 7.1* | 174.2 ± 19.4* | 153.1 ± 32.1* | ||
| Niguldipine | 6.23 ± 1.20 | 14.6 ± 4.32 | 43.0 ± 6.56 | 54.7 ± 5.6 | 58.6 ± 16.5 | 149.3 ± 36.1* | |
| Nitrendipine | 5.9 ± 0.69 | 8.66 ± 1.29 | 28.5 ± 11.0 | 68.1 ± 10.5 | 132.1 ± 24.3* | 162.7 ± 24.4* | |
| Compound Im | 4.65 ± 0.39 | 4.61 ± 0.99 | 7.82 ± 2.00 | 11.7 ± 2.1 | 18.8 ± 3.49 | 24.4 ± 4.34 | |
| Compound IIb | 4.79 ± 0.20 | 5.56 ± 0.12 | 6.03 ± 1.38 | 6.47 ± 1.55 | 11.5 ± 2.13 | 32.8 ± 15.2 | |
| Control |
|
| 142.5 ± 19.9 |
|
| ||
↵* p > 0.05, indicating no statistically significant difference compared to the control