Cell experiment:

KRAS-mutant Non-Small Cell Lung Cancer (NSCLC) A549, H2122, H2009, and Calu6 cell lines are seeded in 384-well black, clear bottomed plates, cultured for 18-24 hours and treated with increasing concentrations of AZD-0364 (7.143 nM, 61 nM, 357 nM, 2.143 μM and 10 μM) and Selumetinib (0-10 μM) in a 6×6 dosing matrix. Cells are seeded at a concentration such that cells in untreated wells are approximately 80% confluent at the end of the assay. After 3 days of treatment, live cell number is determined using a Sytox Green endpoint[1].

Animal experiment:

Mice[1]A549 is a human non small cell lung cancer line carrying an oncogenic mutation in the KRAS gene (G12S). Female nude mice are implanted subcutaneously (s.c.) on the left flank, with 5×106 A549 cells (ATCC) per mouse.Tumor growth is monitored by twice weekly calliper measurement and volumes are calculated. Once tumors have reached a volume of ~200-300mm3 animals are randomised into groups of 7-11 and are treated with a continuous combination schedule of Selumetinib (ARRY-142886) 25 mg/kg BiD and AZD-0364 ethanesulfonic acid 25 mg/kg QD (four hours after first Selumetinib dose), both are dosed by peroral route. Tumor volumes are measured twice weekly after dosing commenced[1].

AZD-0364 is a potent and selective ERK2 inhibitor extracted from patent WO2017080979A1, compound example 18, has an IC50 of 0.6 nM.

AZD-0364 is measured in the ERK2 mass spectrometry and A375 phospho-p90RSK assays with IC50s of 0.6 nM and 5.7 nM, respectively. AZD-0364 can inhibit the growth of a panel of cancer cell lines (A549, H2122, H2009, and Calu6 cell lines) with KRAS mutations as a monotherapy and this effect is synergistically enhanced by treatment with Selumetinib[1].

Tumor growth inhibition by AZD-0364 ethanesulfonic acid (Example 18a) in combination with MEK inhibitor Selumetinib is measured. Studies are performed in the A549 xenograft model. Selumetinib is dosed twice daily (BiD) 8 hours apart and AZD-0364 ethanesulfonic acid is dosed once daily (QD) 4 hours after the first Selumetinib dose. Both compounds are dosed continuously for 3 weeks. Both vehicles are dosed in the vehicle group. Both Selumetinib and AZD-0364 ethanesulfonic acid reduce tumor growth relative to vehicle only control. The combination of Selumetinib and AZD-0364 ethanesulfonic acid results in a reduction in tumor growth[1].

References:
[1]. WARD, Richard, Andrew, et al. DIHYDROIMIDAZOPYRAZINONE DERIVATIVES USEFUL IN THE TREATMENT OF CANCER. WO2017080979A1.