Table 1.
Potency of sodium current inhibition (IC50) by tamoxifen and related compounds
| Drug | NavMs, HEK cells | D220E, HEK cells | E227D, HEK cells | NaV1.2, HEK cells | MDA-MD-231 cells |
|---|---|---|---|---|---|
| Tamoxifen | 830 ± 85 nM (1.08 ± 0.1) | NT | NT | 2.4 ± 0.11 μM (1.05 ± 0.1) | NT |
| Endoxifen | 328 ± 89 nM (1.09 ± 0.1) | NT | NT | 3.1 ± 0.13 μM (0.97 ± 0.1) | NT |
| 4OH-Tam | 297 ± 75 nM (1.14 ± 0.1) | 3.6 ± 0.14 μM (1.17 ± 0.1) | 2.8 ± 0.16 μM (1.13 ± 0.1) | 2.1 ± 0.14 μM (0.96 ± 0.1) | 889 ± 98 nM (0.98 ± 0.1) |
| NM-Tam | 1.1 ± 0.16 μM (1.11 ± 0.1) | NT | NT | 3.2 ± 0.12 μM (0.96 ± 0.1) | NT |
| E-4OH-Tam | 2.3 ± 0.18 μM (1.15 ± 0.1) | NT | NT | 4.2 ± 0.15 μM (0.94 ± 0.1) | NT |
| Z-4OH-Tam | 239 ± 87 nM (1.05 ± 0.1) | NT | NT | 1.2 ± 0.12 μM (0.95 ± 0.1) | NT |
| TTX | NT | NT | NT | NT | 2.6 ± 0.17 μM (1.01 ± 0.1) |
Listed are the average IC50 values derived from fitting the dose-response data to the Hill equation. The average slopes of the fits are indicated in parentheses. The drugs tested in the study were tamoxifen, endoxifen, N-desmethyltamoxifen (NM-Tam), 4-hydroxytamoxifen (4OH-Tam), and the E and Z isomers of 4OH-Tam. NT indicates conditions not tested. Error is equal to SD.