IC50: 5 nM (PAK1)

NVS-PAK1-1 demonstrates high selectivity for inhibition of PAK1 over other PAK isoforms and the kinome in general. NVS-PAK1-1 has a biochemical PAK1 K _d of 7 nM and a PAK2 K _d of 400 nM. NVS-PAK1-1 shows excellent activity in biochemical assays and an exceptional selectivity profile against other known kinases. NVS-PAK1-1 at 6-20 μM inhibits the phosphorylation of the downstream substrate MEK1 Ser289. Consistent with the observation, NVS-PAK1-1 inhibits proliferation of Su86.86 cell line only above a concentration of 2 μM. In contrast, by applying a mixture of NVS-PAK1-1 and PAK2 shRNA, inhibition of downstream signaling and cell proliferation at a significantly lower 0.21 μM concentration are achieved.

NVS-PAK1-1 shows a relatively poor stability in rat liver microsomes (RLM) and this would limit its application for in vivo studies (t _1/2 in RLM 3.5 min).