Ceralasertib (AZD6738)

In four Kras mutant cell lines: H23, H460, A549, and H358, AZD6738 inhibits ATR kinase activity and impairs cell viability. In ATM-deficient H23 cells, AZD6738 strongly synergizes with NSC 119875 to induce rapid cell death. ^[1] In p53 or ATM defective cells, AZD6738 treatment results in replication fork stalls and accumulation of unrepaired DNA damage, resulting in cell death by mitotic catastrophe. ^[2]

In nude mice bearing H460 and H23 tumors, AZD6738 (50 mg/kg, p.o.) results in tumor growth inhibition (TGI), and the the combination with NSC 119875 causes rapid regression of ATM-deficient H23 tumors. ^[1] In nude mice bearing LoVo xenografts, a combination of AZD6738 (50 mg/kg) + IR (2 Gy) avoids toxicity while still maintaining efficacy. ^[3]

• Cell lines

  H23, H460, A549, and H358 cells

• Concentrations

  ~30 μM

• Incubation Time

  48 h

• Method

  Cells are treated in white walled, clear bottom 96-well plates with the indicated doses of AZD6738, NSC 119875, LY-188011, or combination for 48 h. ATP levels are assessed as surrogate measure of viability is assessed using the CellTiter-Glo Luminescent Cell Viability Assay and Safire2 plate reader. Raw data are corrected for background luminescence prior to further analysis. For AZD6738 treatment, log dose response curves are generated in GraphPad Prism 6 by nonlinear regression (log(inhibitor) vs. response with variable slope) of log-transformed (x = log(x)) data normalized to the mean of untreated controls. GI50 values, defined as the dose X at which Y = 50%, were extrapolated from dose response curves.

• Animal Models

  Female athymic nude mice bearing H23 or H460 xenografts

• Dosages

  25 or 50 mg/kg

• Administration

  p.o.