Figure 1. Prexasertib-mediated CHK1 inhibition promotes DNA double-strand breaks resulting in activation of the DNA damage response in vitro.

A, Whole cell lysates of pediatric sarcoma cell lines treated with increasing concentrations of prexasertib over 24h were probed for the indicated total and phosphorylated proteins. B, Cells were treated with prexasertib over a range of concentrations for 24h prior to fixation and immunostaining. Representative images show cells treated with DMSO or 111 nM prexasertib and were taken at 20× magnification using the appropriate filters for each channel. Experiments were conducted twice. (Left) Red: γH2AX; green: cleaved caspase 3; blue: DNA. (Right) Red: ATM phosphorylated at serine 1981; green: DNA-PKcs phosphorylated at serine 2056; blue: DNA.