Effect of target knockdown on radiation survival.

<p><b>A–I</b>) <b>Target knockdown affects survival of IR exposed cells.</b> HCT116 cells transfected with target siRNA alone or in combination with siRNA targeting CHK1. Cells were Mock-irradiated or irradiated with 2 Gy or 5 Gy and viable cells quantified 5 days later. Data plotted are normalized to the respective untreated controls. Filled squares = combined target and CHK1 knockdown (Target/CHK1), open squares = CHK1 only (Li/CHK1), filled triangles = Target only (Target/NT), open triangles = Mock (Li/NT). Error bars represent the variance from the mean from three technical replicates. <b>K</b>) <b>Modulation of RB1 phosphorylation by target knockdown.</b> Parallel POS-LoRBPS780 analysis was used to verify siRNA performance. <b>L</b>) <b>Statistical analysis.</b> Student t-test for cell viability data shown in A–I, (Li/NT vs Targ/NT) probing for a significant effect of target knockdown in unperturbed cells, (Li/CHK1 vs Targ/CHK1) probing for a significant effect of target knockdown in CHK1-perturbed cells, Target/NT vs Target/CHK1 probing for a significant effect of CHK1 knockdown in target-perturbed cells. <b>M, N</b>) <b>Treatment interaction.</b> Assessment for evidence of interaction between radiation and target knockdown. Values represent the degree of net synergism between target knockdown and IR in NT (M) or CHK1-perturbed (N) cell background.