si-HIF-1α inhibits Hippo-YAP pathway activation in non-small cell lung cancer cells. (A) Relative mRNA expression of YAP1 in A549 cells transfected with oe-NC and oe-YAP1. ***P<0.001 vs. oe-NC. (B) Relative expression of YAP1 mRNA in cells transfected with si-HIF-1α and/or oe-YAP1. (C) Cell Counting Kit-8 assay results showing the viability of A549 cells. (D) Fold-change in the p-YAP1/YAP1 ratio and GPX4 protein expression assessed using western blot analysis. *P<0.05 and ***P<0.001 vs. si-NC; ^^P<0.01 and ^^^P<0.001 vs. oe-YAP1. si-HIF-1α, small interfering RNA to hypoxia-inducible factor 1 α; YAP, Yes-associated protein; p-, phosphorylated; oe-YAP1, overexpression of YAP1; oe-NC, overexpression negative control; si-NC, small interfering RNA negative control; GPX4, glutathione peroxidase 4; OD, optical density.