In vitro activity: AZD0156 was identified as a first in class orally available ATM inhibitor with an IC50 of 0.58 nM, showing sub-nanomolar potency in cell based assays of ATM inhibition. Moreover, AZD0156 had selectivities of greater than 1000 fold over other members of the PIKK family enzymes.

Kinase Assay: AZD0156 inhibits the kinase activity of ATM and ATM-mediated signaling, prevents DNA damage checkpoint activation, and disrupts DNA damage repair, inducs tumor cell apoptosis, and leads to cell death in ATM-overexpressing tumor cells.

Cell Assay: HT29 cells are seeded into 384 well assay plates at a density of 6000 cells/well in 40 μL EMEM medium containing 1% L glutamine and 10% FBS and allowed to adhere overnight. The following morning compound of Formula (I) in 100% DMSO is added to assay plates by acoustic dispensing. After lh incubation at 37°C and 5% C02, 40 nL of 3 mM 4NQO in 100% DMSO is added to all wells by acoustic dispensing, except minimum control wells which are left untreated with 4NQO to generate a null response control. Plates are returned to the incubator for a further lh. Then cells are fixed by adding 20 μL of 3.7% formaldehyde in PBS solution and incubating for 20 mins at r.t.. Then 20 μL of 0.1% Triton XI 00 in PBS is added and incubated for 10 minutes at r.t., to permeabalise cells. Then the plates are washed once with 50 μL/well PBS, using a Biotek EL405 plate washer.