Table 2.
Reversal effects of nomegestrol and other reversal agents on drug resistance in MCF7/WT and MCF7/ADR cells (MTT assay)
| MCF7/WT | MSF7/ADR | ||||
| Drug | Concentration (μM) | IC50 | Reversal (fold) | IC50 | Reversal (fold) |
| ADM | 0.40 ± 0.12 | 30.0 ± 6.24 | |||
| NOM | 20 | 0.38 ± 0.09 | 1 | 1.4 ± 0.32*** | 21 |
| 10 | 0.40 ± 0.08 | 1 | 2.5 ± 0.45**† | 12 | |
| 5 | 0.41 ± 0.07 | 1 | 3.8 ± 0.63*† | 8 | |
| MG | 20 | 0.41 ± 0.09 | 1 | 3.0 ± 0.84**‡ | 10 |
| 10 | 0.39 ± 0.11 | 1 | 4.3 ± 1.01*‡ | 7 | |
| 5 | 0.39 ± 0.12 | 1 | 10.0 ± 1.42*‡ | 3 | |
| TAM | 20 | 0.36 ± 0.07 | 0.9 | 1.7 ± 0.37** | 18 |
| 10 | 0.38 ± 0.05 | 1 | 3.0 ± 0.64** | 10 | |
| 5 | 0.41 ± 0.06 | 1 | 6.0 ± 1.14* | 5 | |
| DRO | 20 | 0.40 ± 0.12 | 1 | 2.7 ± 0.81**‡ | 11 |
| 10 | 0.42 ± 0.14 | 1 | 5.0 ± 0.87*‡ | 6 | |
| 5 | 0.39 ± 0.08 | 1 | 10.0 ± 2.04*‡ | 3 | |
| VRP | 20 | 0.36 ± 0.10 | 0.9 | 1.4 ± 0.43*** | 22 |
| 10 | 0.38 ± 0.07 | 1 | 2.1 ± 0.61** | 14 | |
| 5 | 0.39 ± 0.06 | 1 | 4.3 ± 0.91* | 7 | |
Results are means ± standard deviation. Statistical significance compared with control: ***, P < 0.005; **, P < 0.01; *, P <0.05; compared with 20 μM NOM: † P <0.05; compared with responsive concentration of NOM, ‡ P <0.05. ADM, adriamycin; DRO, droloxifene; MDR, multidrug resistance; MG, megestrol; MTT, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide; NOM, nomegestrol; TAM, tamoxifen; VRP, verapamil.