Prexasertib

Prexasertib (LY2606368) is a selective, ATP-competitive second-generation checkpoint kinase 1 (CHK1) inhibitor with a K_i of 0.9 nM and an IC₅₀ of <1 nM. Prexasertib inhibits CHK2 (IC₅₀=8 nM) and RSK1 (IC₅₀=9 nM). Prexasertib causes double-stranded DNA breakage and replication catastrophe resulting in apoptosis. Prexasertib shows potent anti-tumor activity^[1][2]. In Vitro:Prexasertib (LY2606368) inhibits MELK (IC₅₀=38 nM), SIK (IC₅₀=42 nM), BRSK2 (IC₅₀=48 nM), ARK5 (IC₅₀=64 nM). LY2606368 requires CDC25A and CDK2 to cause DNA damage^[1].
Prexasertib (33, 100 nM; for 7 hours) results in DNA damage during S-phase in HeLa cells^[1].
Prexasertib (8-250 nM; pre-treated for 15 minutes) inhibits CHK1 autophosphorylation (S296) and CHK2 autophosphorylation (S516) in HT-29 cells^[1].
Prexasertib (4 nM; 24 hours) results in a large shift in cell-cycle populations from G1 and G2-M to S-phase with an accompanied induction of H2AX phosphorylation in U-2 OS cells^[1].
Prexasertib (33 nM; for 12 hours) causes chromosomal fragmentation in HeLa cells. Prexasertib (100 nM; 0.5 to 9 hours) induces replication stress and depletes the pool of available RPA2 for binding to DNA^[1].
In Vivo:Prexasertib (LY2606368; 1-10 mg/kg; SC; twice daily for 3 days, rest 4 days; for three cycles) causes growth inhibition in tumor xenografts^[1].
Prexasertib (15 mg/kg; SC) causes CHK1 inhibition in the blood and the phosphorylation of both H2AX (S139) and RPA2 (S4/S8)^[1].