They Often Laugh At cdk1 inhibitor Cell Cycle inhibitor - But These Days We Laugh At Them

To give more insights into the properties of this metric, some examples are useful. Having defined the entropy, we next investigated its performance relative to the most widely used methods, on a public profiling dataset of 38 inhibitors on 290 nonmutant kinases.

From each of these scores we determined an inhibitor selectivity ranking, and a rank order difference compared to the entropy Cell Cycle inhibitor method. In addition, to get an overview of the profiling raw data, we appended an activity based heat map. From the rankings it is apparent that each of the earlier methods such as the classic Gini score, S and S generate considerable ranking differences compared to all other methods. This was observed earlier. For the Gini score, this is related to the conversion from IC50 to % inhibition, because the Ka Gini gives more consistent rankings. For the S and the S, the use of a cut off is likely too coarse an approach. For instance in the case of S, there are six inhibitors with a score of 0, making it impossible to distinguish between those highly specific compounds. The newer methods such as Pmax, Ka Gini, and the selectivity entropy, give a more consistent ranking between them.

Therefore we think that Ka Gini and the selectivity entropy are a better general measure of selectivity in this case. Another inhibitor scored differently is MLN 518, which ranks 26st by Pmax, but 14th and 15th by Ka Gini and the selectivity entropy. Again, these differences arise because this inhibitor hits 4 kinases with roughly equal potencies between Cell Cycle inhibitor 2 10 nM, leading to a promiscuous Pmax. However, MLN 518 only hits 10 kinases below 3 uM, making it intuitively more selective than e. g. ZD 6474, which hits 79 kinases below 3 uM. These cases illustrate the earlier point that Pmax underscores inhibitors that only hit a few kinases at comparable potencies. The Gini score and selectivity entropy assign a higher selectivity to these cases. Finally, any selectivity score should be in line with the visual ranking from a heat map.

Also for these new data, we calculated the selectivity metrics. In the ideal case, the selectivity values are similar irrespective of profiling technology. The data of both methods are plotted in Figure 2. All metrics except the entropy and Pmax tend to be quite unevenly distributed.