NVP-CRL-457

Internal kinase profiling indicated a favourable selectivity profile versus 92 biochemical assays (tested at concentrations up to 10 μM). Activity against mTOR IC50 = 2474 ± 722 nM. KINOMEscan with NVP-CLR457 at a concentration of 1 μM showed <35% displacement of reporter-binding against all but a single off-target kinase from the panel of 456 kinases tested (CSF1R 81% reporter displacement). Profiling NVP-CLR457 against a panel of 112 enzymes, transporters, receptors, and ion channels (tested at concentrations of 10 and 30 μM) also indicated a favourable selectivity profile. The only weak activity was determined against two targets, the enzyme PDE4D (IC50 4.3 μM) and the melatonin G protein-coupled receptor MT2 (57% inhibition at 10 μM).

Internal kinase profiling indicated a favourable selectivity profile versus 46 BaF3 cellular assays (tested at concentrations up to 10 μM). Selectivity versus mTOR (mTORC1 complex) was further assessed in a cellular assay measuring Ser235/236-RPS6 phosphorylation in Tsc1–/– null mouse embryonic fibroblasts (MEFs). In this assay, NVP-CLR457 inhibited RPS6 phosphorylation with an IC50 value of 1633 ± 54 nM. To assess selectivity versus ATR and DNA-PK, U87MG cells were treated with the DNA intercalator doxorubicin (1 μM) to induce a DDR response. The addition of NVP-CLR457 at concentrations of 1 and 5 μM did not impact the DDR response as assessed by the activation of p53 (S15 phosphorylation following a 24 h incubation). In the same assay, ATM activity can also be monitored. ATM activity was measured by the extent of autophosphorylation of S1981 following doxorubicin treatment, and NVP-CLR457 at concentrations of 1 and 5 μM also had no effect on this readout.