Figure 3. KL cells and tumors require CPS1.

a, Effect of CPS1 silencing on KL, L and K cells (H1373 (n=4); H1437, H1755, H2023, H2073, H358 (n=6); other cell lines (n=3)). b, Abundance of CPS1 and another urea cycle enzyme, ASS1 in cells from Fig. 3a. CB, cyclophilin B (loading control). c, Effect of silencing CPS1 on H460-EV and H460-LKB1-WT cells (n=11). d, Effects of a doxycycline (Dox)-induced CPS1 shRNA (sh#1) on cell proliferation (n=3). shREN is a Dox-inducible control shRNA. e, Live and dead cell percentages 8 days after induction of CPS1-targeting (sh#1, sh#2) or control (shREN) shRNAs (n=3). f, Growth of anchorage-independent colonies 22 days after Dox induction (n=3). g, Growth of subcutaneous H460-derived xenografts in nude mice in presence and absence of Dox (200 mg/kg) introduced 1 day after implantation. Mean tumor volume and SEM are shown for each group (n=10 tumors except for shCPS#2-Dox, where n=8). Data in a, c-f are the average and SD of three or more independent cultures. In c-f, statistical significance was assessed using one-way ANOVA followed by Tukey’s multiple comparisons test. In g, to calculate significance on repeated measurements over time, two-way ANOVA was used. The mouse xenograft experiment was performed twice for shCPS1-#1 (n=5/experiment, total n=10) and once for shCPS1-#2 and shREN (n=10). All other experiments were repeated three times or more. **p<0.01; ***p<0.005; **** p<0.0001.