Table 1.
Inhibitor constants of DNMT inhibitors for nucleoside transporters
| Ki (μM) | hENT1 | hENT2 | hCNT1 | hCNT3 |
|---|---|---|---|---|
| Azacytidine | 379.5 ± 3.5 | 25.0 ± 0.9 | 11.4 ± 1.6 | 3.5 ± 1.2 |
| Decitabine | 1000–5000 | 5.6 ± 0.5 | 21.6 ± 3.0 | 14.4 ± 4.6 |
| Zebularine | ≍1000 | 22.6 ± 6.1 | 31.3 ± 5.0 | 4.6 ± 0.5 |
Ki values for inhibition of [3H]uridine uptake by DNA-methyltransferase inhibitors in HeLa cells transiently transfected with either hCNT1 or hCNT3 encoding cDNAs. Drug interactions with hENT1 and hENT2 were determined based upon the endogenous activities present in HeLa cells. Ki values were obtained by fitting data by non-linear regression in GraphPad Prism 4.0 software. Data are shown as Ki values ± SEM from two to three independent experiments.