Table 1.
HTRF phosphor-MEK1 assay and HTRF phosphor-ERK2 assay results for PD0325901 and RGD-MEKI conjugates 9a–d, 9f, 9g and 13.
| Compound | BRAF-MEK1 assay (%) a | MEK1-ERK2 assay (%) b | A375 cell c | |||
|---|---|---|---|---|---|---|
| 1 μM | 0.1 μM | 0.01μM | 10 μM | 1 μM | IC50(μM) | |
| PD0325901 | 97.3 ± 1.9 | 95.0 ± 1.4 | 94.0 ± 1.4 | 100.6 ± 0.4 | 100.0 ± 1.5 | 0.00045 |
| 9a | 74.2 ± 7.2 | 30.0 ± 4.7 | 0.3 ± 0.0 | 88.4 ± 1.4 | 66.5 ± 7.7 | 4.4 |
| 9b | 77.6 ± 7.5 | 58.5 ± 8.5 | 6.7 ± 8.5 | 93.5 ± 2.2 | 69.9 ± 3.2 | 2.1 |
| 9c | 91.5 ± 0.7 | 48.5 ± 9.5 | 38.9 ± 10 | 99.5 ± 0.7 | 63.8 ± 2.9 | 4.0 |
| 9d | 97.9 ± 2.4 | 46.0 ± 12.5 | 26.1 ± 15 | 99.9 ± 1.4 | 80.5 ± 2.0 | 5.6 |
| 8b | 57.5 ± 1.7 | 39.6 ± 9.3 | 12.5 ± 3.2 | 83.4 ± 1.2 | 29.1 ± 12.0 | 14.2 |
| 9g | 78.8 ± 4.4 | 39.0 ± 7.2 | 25.9 ± 11 | 91.8 ± 2.5 | 40.6 ± 5.5 | 0.65 |
| 9f | 80.5 ± 2.9 | 42.6 ± 5.6 | 39.0 ± 7.4 | 95.0 ± 1.0 | 49.1 ± 7.8 | 3.1 |
| 13 | 95.7 ± 1.9 | 95.1 ± 0.9 | 48.4 ± 3.2 | - | - | 0.0176 |
a BRAF-MEK1 assay (HTRF phosphor-MEK1 assay) was used to determine the activity of RGD-MEKI conjugates to inhibit the phosphorylation of the inactive MEK1 kinase. Values are means of three experiments, standard deviation is given after them; b MEK1-ERK2 assay (HTRF phosphor-ERK2 assay) was used to determine the activity of RGD-MEKI conjugates to inhibit the active MEK1 kinase to phosphorylate the inactive ERK2 protein. Values are means of three experiments; standard deviation is given after them; c In vitro anti-proliferation assay on melanoma A375 cells by the SRB method.