Overexpression of PDK1 partly rescues <i>MAPK4</i>-KO tumor cell resistance to PI3K blockade.

(A) Plate colony formation assays and (B) soft-agar assays on WT or engineered MAPK4-KO SUM159 and MDA-MB-231 cells with 0.5 μg/ml Dox-induced expression of PDK1 (iPDK1), MAPK4 (iMAPK4), or control (iCtrl). Scale bar: 500 μm. Quantification data as means ± SD. P values by two-way ANOVA followed by Sidak’s multiple comparisons. *P ≤ 0.05, **P ≤ 0.01, ***P ≤ 0.001, ****P ≤ 0.0001. ns, not significant. Data are representative of at least 3 independent experiments. The numerical values underlying the figures can be found in S1 Data. MAPK4, mitogen-activated protein kinase 4; PDK1, phosphoinositide-dependent kinase-1; WT, wild type.