Consequences of ROCK1 knockdown. Knockdown levels of 2 shRNAs targeting ROCK1 are presented for messenger RNA (mRNA) (A) and protein (B). (C) Fraction of apoptotic cells after ROCK1 knockdown (red) and a nontarget control shRNA (scramble, black) at indicated time points. (D) Percentage of initial cell counts after transduction of cells with shRNAs targeting ROCK1 (red) and a nontarget control (black) at indicated time points. Due to the limited amount of primary cells available, the experiments shown in panels A and B were done with HeLa cells, whereas primary AML cells from our donor (AML2) were used in the experiments depicted in panels C and D. The cell source is indicated at the top of each panel. The means and standard deviations of experiments done in triplicates are given in panels A and D; significance was assessed by means of Student t test; *P < .05, ****P < .0001.